SULPHONATION PLANTSULPHONATION PLANT

Capacity 3.000 Kg/hCapacity 3.000 Kg/h

OPERATING MANUALOPERATING MANUAL

Index

Introduction Page: 3

1 Plant capacity Page: 4

2 General process description Page: 5

3 Raw material and products specifications Page: 19

4 Plant start-up operations Page: 25

5 Normal run and controls Page: 49

6 Normal shut-down Page: 57

7 Emergency shut-down Page: 62

8 Interlock system Page: 56

9 Material balance Page: 58

10 General maintenance Page: 74

11 Annexes Page: 76

11.1 Alumina Tanks T-102 A/B Page: 76

11.2 General Notes About Sulphur Filtration Page: 77

11.3 Converter Catalyst Loading Instructions Page: 82

11.4 R-301 scrubber Page: 84

2

This operating manual has been developed following the criteria that the operators have

some knowledge of chemical plants and have consequently familiarity with equipment,

which normally are installed in them.

For this reason the manual will describe the operations showing their meaning leaving

to the operators’ experience the correct way to realize them.

For instance, when we say “start the organic pump“, the manual assumes that the

suction and delivery valve have been checked and are in correct position; or “open

steam to the exchanger”, the manual assumes that the steam and condensate valves

have been positioned in the right way, and so on.

Moreover, this manual is addressed to people who are expert in chemistry and in

chemical plants, so that they can manage the operations described there with the

necessary interpretation and responsibility.

3

1) PLANT CAPACITY

The plant has been designed to produce 3.000 Kg/h of duodecilbenzene sulphonic acid

(LABS), starting from sulphur and linear duodecilbenzene, using a multitube falling film

reactor.

On the base of 330 working days/year and continuous run the plant can produce 2.376

tons/year of LABS.

Alternatively it can work at campaigns, but it can not be managed stopping and

restarting it frequently, because the time necessary for its steady conditions is too long

and not compatible with frequent shut-downs. The shorter campaign time we suggest is

one week.

The produced LABS is stable and can be stored as it is in stainless steal tank. It can be

used inside the factory or sold outside. Its quality is in line with the international

standards.

The neutralization section has been not installed at the moment, but it can be erected

any time being the relevant space already foreseen.

This film reactor can also sulphonate the most common fatty alcohols used in

detergency, but the plant can not now process them without the neutralization section,

because the fatty alcohols sulphonic acid is unstable and must be neutralized

immediately at the exit of the sulphonation reactor.

Only when the neutralization section will be functioning, the fatty alcohol sulphonation

will be possible.

The nominal plant capacity in case of fatty alcohols decreases as per the following list

due to the necessity to operate at lower SO3 concentration in the reaction gas:

Raw materials M.w Production kg/h

Linear alkylbenzene 242 3.000

Branched alkylbenzene 245 3.000

Lauryl alcohol c12 / c-14 207 2.700

Ethoxylauryl alcohol3 moles e.o. 339 2.550

4

Natural alcohol c16/c18 258 2.700

2) GENERAL PROCESS DESCRIPTION

The LAB sulphonation is a reaction between SO3 (sulphuric anhydride) and LAB where

SO3 generates the SO3H group linking itself to the benzene ring.

Raw materials of this reaction are alkylbenzene, mainly linear, sulphur and air.

Sulphur, if supplied in solid form, is melted and burned with air excess to give SO2

which is oxidized to SO3 using V2O5 catalyst.

The exhaust gas, which after sulphonation contains some unreacted SO3, some not

converted SO2 and some dragged organics, is purified before sending it to the

atmosphere.

2 . 1 ) PROCESS CHEMISTRY

The sulphonation reaction takes place in mixed phase gas/ liquid, being the gas a

mixture of sulphuric anhydride (SO3) and air and the liquid linear duodecylbenzene

(LAB) or duodecylbenzene not linear (branched)(this last is rarely used because is not

biodegradable and so it is refused by the market).

The main reaction can be so shown:

C6H5-(CH2)11-CH3 + SO3 = C6H4-(CH2)11-CH3

(LAB) |

SO3H

(LABS)

The LABS is a quite strong acid, liquid and stable at room temperature. It can easily be

stored and shipped (see physical properties on paragraph 3) It can be neutralized by

the bases (caustic soda, sodium carbonate, others).

The above reaction is exothermic and so the reaction must be cooled.

5

The quality of the acid is judged by the colour (measured in Klett scale), by the

unsulphonated LAB (free oil), by the free sulphuric acid (H2SO4).

To understand how to manage the reaction, we have to examine these three

parameters:

a) Colour (from dark yellow to brawn)

It is due to the carbonisation of the organic compounds (LAB).This carbonisation

takes place because of too high reaction temperature, for too high SO3

concentration, for presence of sulphuric acid in the SO3 gas stream.

- Reaction temperature.

In the falling film multitube reactors the reaction between SO3 and LAB is very

soft, because SO3 reacts on a 0,3 mm film of LAB which forms in the inner face

of each reaction pipe, thanks to a special design of the distribution head of the

reactor itself.

Moreover, all the reaction pipes are cooled very deeply by means of a big mass

of water.

The water temperature should be as low as possible with a delta T between

inlet and outlet of 1-2 degrees centigrade.

The 80% of the reaction takes place in the first meter of the sulphonation

reactor where the reaction temperature reach a maximum pick around 80 ° C.

Lower is the pick lower is the Klett colour of the resulting LABS. For this reason

we divide the cooling water flow in two streams: 60% on the top, 40 % on the

rest.

- SO3 concentration.

6

As shown above, one mole of LAB reacts with one mole of SO3. This ratio must

be, of course, absolutely respected. As we will see later, this is obtained in a

simple way checking the acidity at reactor exit.

But the SO3 concentration in the air is also very important to avoid

carbonisation.

Normally 5% SO3 in air is considered a good value for getting a good colour

LABS and also an acceptable plant capacity. As a matter of fact that more

diluted is SO3 more gas mass must be circulated into the plant reducing, with

the same equipment, the plant capacity.

Any way, just to complete the picture, we can say that more diluted is SO3

smoother is the reaction and better is the colour.

- H2SO4 in the SO3/air stream

The sulphuric acid reacts strongly with LAB and out of control way, burning the

LAB itself. On the basis of this reality, in the film reactor sulphonation plants

much attention must be brought for avoiding its presence and formation and, if

any, for eliminating it as much as possible before the reaction.

The H2SO4 presence in the SO3/air stream, in form of droplets or mist, is

generated mainly by the reaction of SO3 with moisture .That explains way we

dry the air necessary for the reaction through a drying system enough

sophisticated as we will see later.

However, the air is not the only source of moisture. It can be introduced by the

LAB itself and this is the reason because we require a LAB specification much

restricted in this sense.

Sulphuric acid could be also present in the sulphur itself and also for this

reason, but not only, during the melting and before filtration could be added

some neutralising agent.

Anyway, before reaction, we have foreseen several traps where H2SO4 droplets,

if any, are collected and separated: at the bottom of the SO3/air coolers, in the

7

separator after coolers and at the bottom of the special filter installed just before

reactor.

b) Unsulphonated LAB

This impurity has the following meaning:

- LAB remained not sulphonated after reaction

- Material not sulphonated because is not sulphonable

The unsulphonated LAB (free oil) depends from the ratio between the moles of the

reactants: SO3 and LAB.

In other words, if we increase the ratio SO3/ LAB, the unsulphonated LAB decreases,

but the Klett colour could increase. There is a balance between colour and free oil,

which should be practically searched case by case.

The unsulphonables are materials which can not be sulphonated at least in the

conditions we are operating and must be considered lost raw material. They are

impurities of LAB and their maximum quantity is fixed in the LAB specifications (LAB

sulphonability).

c) Free sulphuric acid

Although we have done as much as possible to avoid the H2SO4 formation, in the final

product we will find always a certain concentration of free sulphuric acid, mainly due to

reaction of water content in LAB which reacts with SO3 in the sulphonator :

H2O + SO3 = H2SO4

Another source of free H2SO4 is the formation of anhydrides which gives free water

which reacts with SO3:

8

2 C6H5-(CH2)11-CH3 + 2 SO3 = C6H4-(CH2)11-CH3 + H2O

|

SO2

|

O

|

SO2

|

C6H4-(CH2)11-CH3

H2O + SO3 = H2SO4

These anhydrides are then decomposed before storage in the hydrolyses section by

addition of water giving again sulphonic acid:

C6H4-(CH2)11-CH3 + H2O

|

SO2

|

O =2 C6H4-(CH2)11-CH3

| |

SO2 SO3H

|

C6H4-(CH2)11-CH3

9

2 . 2 ) PLANT DESCRIPTION (reference to P and I: SP3-AM-1021/1027)

The plant can be divided in six sections:

2.2.1 Air drying

2.2.2 Sulphur melting and filtration

2.2.3 Sulphur combustion

2.2.4 Conversion

2.2.5 Sulphonation

2.2.6 Exhaust gas treatment

2 .2.1) Air Drying (P and I: SP3-AM-1021)

The air, drawn from the atmosphere, is measured by a calibrated flange (FIR-161) and

then distributed between combustion air in the sulphur furnace and quench air in the

converter; the rest, if any, is sent before the demister F-104.

The atmospheric air is compressed by compressor CO-101 at 0.9 bar maximum.

Really the pressure on the compressor delivery is fixed by the pressure drop through

the plant at the flow rate required by the plant conditions.

CO-101 is a volumetric type, that is it compresses always the same quantity of air,

being used only part of it venting the rest to the atmosphere through the valve PCV-101.

CO-101 is a noisy machine, it is closed in a noise proof container, has two silencers:

SL-101 on the suction and SL-102 on the delivery.

After compression the air temperature is about 130° C. This air has to be cooled and

dried. For this purpose there is the exchanger E-101, cooled by water, and E-102

cooled by chilled water. After E-101 the temperature is about 30°C and no condensate

is separated; after E-102 the temperature is about 3-5 °C and consequently being the

10

air in saturation condition, the water separates and is discharged from the bottom. The

separator F-102 provides to eliminate the last water mist still contained in the air stream.

At the exit of F-102 the moisture content corresponds to the saturation at the

temperature of 3-5 °C.

Also this small amount of moisture must be eliminated; this is realized with the driers T-

102 A/B filled with activated alumina. The air enters the bottom and goes out from the

top, reaching a dew point in the range of –50/-70 °C.

The driers T-102 A/B work alternatively, one in operation the other in regeneration,

being 8 hours the working cycle.

The regeneration is realized in counter-current with hot air (4 hours) coming from E-

108/109 exchangers at about 200° C and then with cooling (4 hours) by water in the

exchanger E-103. The fan BL-101 provides the circulation of regeneration air in the

heating and cooling phase.

The alumina drying system is completely automatic; it is controlled by PLC.

The exchanger E-104 is used only in start-up, when hot water from E-108/109 is not

available.

For details on this system see later the appendix n.1 “drying alumina beds”.

The dried air at the exit of T-102 A/B has about 30 °C and it is ready to be sent to

sulphur combustion and converter.

The chilled water necessary for the exchanger E-102 is supplied from the chilling unit

shown in the P and I SP3-AM-1022.

The tank T-101 contains a 30% glycol solution in water. This solution is recycled by

means of the pumps P-101 A/B through the chiller CB-101, where it is cooled at about –

2 °C. The chilled glycol/water solution enters the exchanger E-102, cooling the air in

counter-current.

At the exit of the exchanger the glycol solution has a temperature of about 5°C and

comes back to the tank T-101.

For detail of the chiller see the relevant technical documentation.

11

2 .2.2) Sulphur Melting And Filtration (P and I: SP3-AM-1023)

The sulphur is another raw material necessary for the sulphonation. It is usually

supplied in solid form or melted. If in solid form it has a flakes shape. In such a case it

must be melted and, if necessary, it must be filtered before being fed to the furnace BR-

101 for generating SO2.

The reason of the sulphur filtration is strictly connected to its quality, particularly to its

content of ashes. In fact the ashes makes dirty the furnace ,encrust the equipment,

damage the converter catalyst, but mainly give problems to the sulphur dosing pumps.

The plant is equipped with a complete section designed for a deep filtration (see P and

I SP3-AM-1023 ) and, moreover, with an additional light filtration after the tank T-104

(F-103A/B see SP3-AM-1024).

Being the deep filtration an always heavy operation, we suggest evaluating case by

case the real necessity to filter the sulphur deeply instead of bypassing this section and

use only the light filtration.

The deep filtration can be done without filter aid or with filter-aid, depending on the type

of impurities contained in the sulphur.

For sulphur quality specifications see appendix n.2, raw materials specifications.

The sulphur melting section is formed by:

- Melter H-101

- Filter aid tank T-105

- Filter F-105

- Filtrated sulphur tank T-104

The melter H-101 is divided in two connected parts: melting zone and mixing/pumping

zone.

12

In the first zone sulphur is charged in the relevant hopper .On the bottom of the hopper

a double order of coils, fed by 6 bar steam, provides to melt the sulphur which falls

down in liquid form.

The melting sulphur temperature is around 115°C .but it has to maintain at about 150°C,

because at this temperature it has the minimum viscosity.

In the mixing /pumping zone, the stirrer AG-101 maintains the ashes in suspension, so

that the pump P-105 can easily transfer liquid and solids to the filter F-105.

A floating level indicator is installed on the middle.

Inside the tank are installed several coils fed with steam to maintain the temperature

around 150°C.

The filter aid tank T-105 receives the liquid sulphur from H-101 by means of pump

P-105 and provides to prepare the filter aid suspension to form a proper panel on the

nets of the filter F-105.

The stirrer AG-102 maintains in suspension the filter aid, while the pump P-106

transfers it to the filter F-105.

A local floating level is installed.

The tank has a jacket fed by 6 bar steam.

The filter aid suggested for this use is EUROPERL® 700 (see specifications in appendix

n.2)

The filter F-105 is horizontal type, multi panels and completely jacketed and heated by 6

bar steam.

For more details about sulphur filtration see annexe n° 2 General Notes About Sulphur

Filtration.

After filtration, the liquid sulphur is stored in the tank T-104, from which is fed to the

sulphur burner BR-101 by means of the dosing pumps P-102A/B.

T-104 tank is vertical type, jacketed and heated by 6 bar steam. A level indicator with

min./max alarm is installed. Its capacity is around 4 m3 and, when full, will assure 24

hours of production.

All the lines and equipment of this section are jacketed and heated by 6 bar

steam .Much attention should be paid to a good functioning of the heating system of this

section, other wise the sulphur could solidify and cause troubles to the production.

13

There is a simple way to ascertain that a line or equipment is well heated: put on the

line or equipment a small piece of solid sulphur. If sulphur melts easily in short time the

line or the equipment is properly heated.

2.2.3) Sulphur Combustion (P and I: SP-AM-1024)

From tank T-104, the sulphur is filtered again through filters T-103 A/B, and then is fed

to the furnace BR-101 by the dosing pumps P-102 A/B.

The sulphur enters the top of BR-101 together with an excess of combustion air and

burns falling down in the combustion chamber which is filled of well set series of

refractory bricks. The sulphur place itself on the bricks surface and burns completely

giving SO2.

The reaction is exothermic and the temperature of the mixture SO2/air depends from

SO2 concentration. Practically we can say that the percent concentration corresponds to

the temperature multiplied by hundred:

6 % conc. corresponds about to 600 °C

7 % conc. corresponds about to 700 °C

And so on.

In the sulphonation plant we assume the furnace temperature at about 750 °C, which is

optimal for material resistance and equipment capacity .That means the air we supply

together with sulphur will give about 7,5 % concentration of SO2. The air quantity is

measured by the calibrated flange (FIR-162).

But for the conversion of SO2 to SO3 we have to cool the SO2/air mixture at 430 °C to

assure a good conversion yield. So, before conversion in the converter R-101, the gas

passes through an exchanger/boiler E-107, where it cools up to that temperature

producing 12 bar steam which is then reduced to 6 bars and sent to general steam net.

The boiler E-107 is fed by soft water through the pumps P-104 A/B. The tank T-106

receives soft water from the b.l. The temperature of outlet process gas is regulated

manually by a special internal by-pass of the boiler itself.

Sulphur furnace and converter preheating.

Before start-up the sulphur furnace and converter must be preheated.

14

Sulphur has its self ignition temperature at about 300 °C and the conversion catalyst

must work at 430 -450 °C. So we must bring the furnace to a temperature well higher

than 300°C and the converter to 430-450 °C.

This preheating is realized using dry air from drying air section which is first heated at

about 130°C in the exchanger E-105 and then brought to 500-550°C by the electric

exchanger E-106.

Sulphur furnace and converter are preheated in series/parallel venting the exhausted air

through the normal process line. This operation takes 5-6 hours starting from room

temperature.

After preheating, the exchangers E-105 and E –106 are excluded and stopped.

Furnace and converter are now ready for start-up.

2.2.4) Conversion (P and I: SP3-AM-1025)

(See Monsanto Converter Catalyst Loading Instructions, Annex 11.3)

The mixture SO2/air from the exit of E-107 is conveyed to the converter R101.

This equipment has four conversion beds filled by V2O5 catalyst in form of pellets or

rings.

The gas mixture passes through these beds and the SO2 is converted to SO3 following

the reaction:

2 SO2 + O2 = 2 SO3

This reaction is exothermic, so the gas must be cooled at each bed outlet by means of

cold and dry air (quench air from compressor delivery).

The gas enters the first bed at about 450 °C and goes out at about 614 °C. The quench

air cools it at 440 °C before entering the second bed. At second bed outlet the gas

temperature rises to 468°C and is again cooled to 440 °C before the third bed. At third

bed outlet the gas has reached 445 °C and it is cooled again to 425°C. At the fourth bed

outlet the gas has practically no temperature increment. That means the conversion is

15

already completed after the third bed, being about 80% realized after the first bed, the

last operating like a guard.

After converter 98.5% SO2 has been oxidized to SO3.

The mixture SO3/air before sulphonation reaction must cooled to 50-60 °C. This is

realized cooling the gas by two exchangers E-108/E-109 working in series and cooled

by atmospheric air.

The fan BL-102 sends the cooling air in parallel to the exchangers. The hot air from the

exchangers exit has about 200 –220 °C and is used for regeneration of drying alumina

beds (see P and I 1021)

After the cooling exchangers a mist separator is installed (F-104). From the bottom of

the exchangers and F104 some quantity of oleum is collected and periodically drained

to T –103 tank.

This oleum is a good quality by -product and its quantity depends, as already explained,

from the moisture content in the total system (normally 4-5 Kgs/day).

It can be recovered by the pump P-103 in a portable vessel and used where necessary

or sold.

2.2.5 ) Sulphonation (P and I:: SP3-AM-1026)

The mixture SO3/air 4% passes through the special filter F-202 separating the last

traces of sulphuric acid or oleum, if any. Then it enters the organic chamber in the top of

the reactor R-201.

The LAB stored in T-201, is also pumped by P-201 to the organic chamber in the top of

the reactor, being its quantity measured and regulated by a mass flow meter FIC-201,

by means of the inverters of the pumps.

The LAB is filtered by F-201 before entering the reactor.

In this way LAB and SO3 reacts in co-current in the reactor top giving the correspondent

sulphonic acid.

The reaction heat is taken off by the cooling water circulated through the reactor shell

by the pump P-204.

16

The delivery of this pump is divided in two streams: 60% roughly to the upper part, 40%

roughly to the lower part, being this distribution regulated manually checking the outlet

temperature.

The tank T-202 , kept in light pressure by the air bomb T –210 , provides in case of

emergency to feed a sufficient LAB quantity to the reactor head avoiding so the burning

of LAB itself because of excess of SO3.

From the reactor bottom we collect LABS, which is first sent to the separator R-202: the

liquid (LABS) falls to the bottom, while the gas flows from the top to the cyclone CY-201

for the liquid last separation. The exhausted gas flows to the depuration treatment (P

and I 1027)

From R-202 the LABS reaches the aging tank R-203, where the reaction is

completed .Then by the pump P-202 is sent to the storage. The level regulator LIC-201

drives the extraction pump inverter.

Before storage small amount of water is added to the LABS for breaking the anhydrides

and catch the unreacted SO3, stabilizing the LABS colour. This operation is lightly

exothermic and so the LABS is cooled by the plate exchanger E-202.

2.2.6) Exaust Gas Treatment (P and I: SP3-AM-1027)

The exhaust gas coming from the top of cyclone CY- 201 contains all the not converted

SO2, traces of not reacted SO3, small amount of organic and traces of H2SO4. This gas,

before being discharged to the atmosphere must be treated to eliminate the above

mentioned impurities.

In this section the SO3, H2SO4 and organic are caught by the electrofilter F-301, while

SO2 is absorbed in the tower R-301 by NaOH giving sodium sulphite/sulphate solution,

which can be recovered.

From the F-301 bottom we collect a dark viscous oil (the quantity depends from

sulphonation conditions and from LAB quality but is in range of 0,25-0,5 lts/h ).Its

composition is a mixture of

H2SO4 / oleum 30%, LAB/LABS 60%, 10% heavy sulphonated products.

This oil is generally recovered adding it to the final product.

17

As far as the sulphite/sulphate solution is concern, there are two ways for managing the

absorption tower R-301 with two different results: at high Ph (14) with formation of only

sodium sulphite or at Ph close to neutrality (7.2-7.5) with formation of roughly 80%

sulphate and 20% sulphite.

This sulphite/sulphate solution can have a variable concentration between 5 and 13%

depending from the operating condition.

If the absorption is carried out at almost neutrality, it is of course preferable because,

after complete oxidation, the sulphate solution could be recovered in the detergent

plant.

On the other hand, to operate close to neutrality requires much more accuracy.

The exhaust gas, after this depuration treatment, is vented to the atmosphere. It may

contain less than 5 ppm of SOx.

18

3) RAW MATERIALS, CHEMICALS AND PRODUCTS

SPECIFICATIONS

3.1) RAW MATERIALS

3.1.1) Sulphur

Characteristics of Amorphous Sulphur normally used in sulphonation.

- Humidity 0.01 %

- Bitumen 0.02 % max.

- Ashes 0.05 % max

- Titer 99.70 % min

- H2SO4 0.01 % max

- H2S Absent

- Arsenic Absent (0.25 ppm. max)

- Selenium Absent (2 ppm max)

- Tellurium absent

- Fluorine absent

19

3.1.2) Linear duodecylbenzene

- Sulphonability 98 % max

- Molecular weight 240-255

- Aspect Liquid, limpid

- Colour APHA 10 max

- Density at 15° C 0.850 – 0.870 kg/lt.

- Water 0.05 % max.

- Iron 1 ppm max.

- Bromine number 0.05 max

- Refraction index 1.485-1.487

- Aniline point 11° - 14°

- Pour-point -70° max.

- Distillation curve 285° - 305° C

- Doctor test negative

Composition (by weight)

- Below C10 0.5 % max

- C10 15 % max.

- C10+C11 38 – 60 %

- C12 25 – 40 %

- C13 30 % max

- C14 5 % max

- Above C14 0.5 % max

- 2 Phenyl Isomers 25 ÷ 35 %

- Visocsity 9 Cps at 38° C

- Flash Point 120° C

20

3.1.3) Branched duodecylbenzene

- Aspect Limpid, colourless, slightly fluorescent.

- Water Traces

- Density at 20° C 0.870 – 0.875 kg/lt.

- Molecular weight

(cryoscopic benzenic)

233 - 248

- Distillation curve

(method ASTM D158) IP123

- Dry point 300° C

- 95% 297° C

- Boiling point 275° C

- Bromine number 0.01 max

- Flash point 132 min.

- Doctor test negative

- Viscosity 8 – 9 Cps at 50° C

- Aniline point 11 – 14° C

- Colour 20 Hazen (30 Saybolt)

- Refractory index 1.4855 – 1.4865 25° C

3.1.4) Caustic soda 50%

- Appearance Clear colourless liquid

- Odour None

- Specific gravity (20° C) 1.49 – 1.51

- Sodium hydroxide 46.5 – 47.5 %

- Sodium carbonate 0.025 %

- Sodium chloride 40 ppm

- Sodium sulphate 8.0 ppm

21

- Iron oxide as Fe203 4.0 ppm

- Calcium oxide 10 ppm

- Magnesium oxide 1 ppm

- Silica as Si02 8.0 ppm

3.2 CHEMICALS

3.2.1) V2O5 catalyst

Supplier : Monsanto

Type : XLP-120

XLP-110

First bed : litres 800 XLP-120

Second bed : litres 900 XLP-110

Third bed : litres 1000 XLP-110

Fourth bed : litres 1000 XLP-110

Total : litres 3700

3.2.2) Activated alumina

Type: A.A.2-5 Grade D

Aspect: high purity alumina beads

Diameter: 2 to 5 mm.

Physical properties:

-smaller than 2 mm. 2% w. max.

-larger than 5 mm. 2% w. max.

-loss on ignition (1000°-300°C) 7% w. max.

-tapped bulk density 0,78 min.- 0,85 max. Kg/lt

-surface area 300 min. m2/gr

-particle crushing strength 14 min. daN

-attrition resistance (AIF) 99% w.

-static adsorption (at 60%RH) 19 min-24 max. % w.

Chemical analysis:

22

-Al2O3 93,8% w.

-Na2O 5.000 max. w.ppm

3.2.3) Ethylene Glycol ECOGEL: E

SPECIFICATIONS

Specific Weight at 15/15°c 1.125-1.130

pH (50% water solution in vol.) 9.0-10.0

Apparent content of water 3.5 max

Alkalinity reserve 15 min.

ashes 1.5 max

Freezing point (50% water solution vol.) -38° C max

Boiling point 170° C min

Boiling point (50% water solution vol.) 108° C min

Effects on the piping surfaces none

Odour light

foamy absent

Water solubility complete

Resistance to hard waters clear

3.2.4) Liquid sulphur filter aid: PERLITE FILTER AID (EUROPERL® 700)

TYPICAL PHYSICAL PROPERTIES

Physical form Dry powder

colour white

Permeability (darcy) 2.6

Cake Density (g/l) 205

Moisture (% as shipped) 1%

Floaters (% by volume) 44.8

23

TYPICAL CHEMICAL PROPERTIES (% by weight unless otherwise stated)

SiO2 72

Al2O3 14

Fe2O3 0.7

TiO2 0.1

CaO 0.3

MgO 0.1

Na2O 4

K2O 8.8

3.3. PRODUCTS

Linear alkylbenzene sulphonic acid

-active matter concentration 97% w. min.

-free oil 1,5%w.max.

-free H2SO4 1,5%w.max.

-Klett colour 30-40 max.

(5% A.M. water solution, 40 mm. CELL, n. 42 filter)

Branched alkylbenzene sulphonic acid

-active matter concentration 96,5 %w.min.

-free oil 1,8%w.min.

-free H2SO4 1,5%w.max.

Klett colour 50-60

(5% A.M. water solution, 40 mm. CELL, and n.42 filters)

24

4) PLANT START–UP OPERATIONS

INTRODUCTION

These operations must be considered normal start-up operations. That means the plant

commissioning and the first start-up have been already performed: all the equipment

has been tested and they worked properly, the electrical and process panel and all the

instrumentation have been calibrated for working in the requested range and they

controlled and regulated the plant run satisfactory.

All the utilities: steam at 10 and 6 bars, cooling water, softened water, compressed air

and electric power are ready and available.

The raw materials LAB and solid sulphur are available to be fed to the plant.

The plant is ready for normal start-up.

Plant conditions:

- Electrical power is regularly fed to the plant

- All the machinery is stopped.

- The sulphur melter and the other sulphur equipment (T-105., T-104, F-105) are

empty.

- The sulphur furnace is at room temperature.

- The converter is at room temperature.

- The R-301 is full of sulphite/sulphate solution at ph 7,2-7,5 .

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4.1) PRELIMINARY OPERATIONS

- Interlock exclusion

- Utilities availability check

- Sulphur melting and filtration start-up

- Exhausted gas section start-up

- Chilling station start-up

- Air drying section start-up

- Furnace and converter pre-heating start-up

4.1.1) Interlock Exclusion

The plant interlock must be excluded in this start-up phase. That means that all the

permissions or interlocks which before linked some machineries among them or with

some instrumentations have been temporally cancelled. Thus, all the machinery can be

independently started.

Consequently this start-up phase must be controlled by the operator with much attention

under the supervision of the plant supervisor.

4.1.2) Utilities Availability Check

1) Instrumentation compressed air:

Check the compressor is running and the pressure on the air line to the plant is in the

range of 8 bars.

Check that all the instrumentation is regularly fed by air.

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2) Cooling water

Be sure that the main raw water tank (main storage) is full of water.

Check the raw water make-up line is regularly in pressure feeding the cooling tower and

the softening station.

Check the top fan of the tower is working properly.

Check the pressure on the inlet plant line is in the range of 3 bars.

Check that the following equipment is regularly fed by cooling water and the relevant

inlet outlet valves are opened: E-101, E-103, R-201, and R-203.

Check the cooling water return line is working properly discharging to the cooling tower.

3) Steam

The main boiler must be running.

Be sure the softening station is regularly working and the alkalinised water is fed to the

main boiler and to T-106 when necessary.

Check the pressure of the main boiler outlet line is in the range of 12 bars and the

relevant reductions to 10 bars and 6 bars are operating.

The following equipment must be fed by steam: E-104 (10 bars), E-105, H-101, T-105,

F-105, T-104, T-103 A/B, all the jacketed sulphur lines, R203, E-301, and T-301. Check

the inlet and outlet (condensate) lines are properly prearranged and the steam is flowing

regularly.

4) Steam condensate

All the steam condensates are conveyed to the softened water tank where they are

integrated by the softening station, if necessary. After alkalinization

condensates/softened water are fed to main boiler and to T-106).

Check all the condensate return lines are working regularly.

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5) Softening station

Check that the softened water tank is full and all the system is running regularly. Check

the level of the alkaline solution tank.

4.1.3) Sulphur Melting And Filtration Start-Up

Before starting any operation in this section, we must be sure that all the equipment,

lines and machinery are hot enough to assure a temperature higher than sulphur

melting point (115 °C).

Normally the right temperature adopted is 150°, which is easily reached with 6 bars

steam fed to the jackets and coils.

It is practical procedure to check the temperature of lines and equipment putting a small

piece of sulphur on them: if the temperature is right the sulphur will melt in a few

seconds.

Check all the coils of the melter: all of them must be operating

Check the heating jacket of T-105

Check the heating jacket of T-104 tank

Check the heating of the filter F-105

Check the heating of all the jacketed lines and valves, including also those which at the

beginning we have not planned to use.

Check the heating of filters F-103 A/B

The vertical sulphur pumps P-105 and P-106 are jacketed: do not forget to check the

heating.

Check the heating of the dosing pumps P-102 A/B and be sure that the cooling water to

the transmission shaft) has been opened.

ONLY WHEN WE ARE SURE THAT ALL THE SECTION HAS BEEN CHECKED AND

IT IS HOT IN ALL THE POINTS, WE CAN PROCEED TO CHARGE, MELT THE

SULPHUR AND START THE STIRRERS AND PUMPS.

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Charge sulphur in the melter H101 and check periodically the level.

When the level reaches about 20% start the stirrer (AG –101) and check it is properly

working (amperage).

Check that all the valves in the sulphur lines are closed.

Following the sulphur quality, we have to decide whether is necessary to filter it and, if

yes, whether we have to perform the filtration with filter aid or without it. A sample

melted in laboratory can be useful to decide.

If is not necessary to filter it, the filter F-105 has to be by-passed, sending the melted

sulphur directly to the storage tank T-104.

If it has to be filtered without filter aid ,the tank T-105 has not to be used .The liquid

sulphur has to be pumped directly through the filter F-105 and then to the T-104.

In case of filtration with filter aid proceed as follows:

-after the level reached 70% about in H-101, start the pump P-105 ( check it is properly

working) and transfer sulphur to the T-105 tank until the level is at about 70 % .Stop P-

105.

Start AG-102 and check the amperage.

Charge the filter aid to the T-105 tank: n.1 Kg of filter aid / n. 1 m2 of filtering surface.

Total about 3 kg of filter aid.

Check that the valves are prearranged to recycle sulphur with filter aid through the filter

F-105 coming back to T-105.

Start pump P-106, checking amperage. All the other valves should be closed. Thus, the

filter aid will be set on the filter nets forming a panel, which will help the next filtration.

From this moment on the pressure at F-105 inlet should be never stopped; otherwise

the filter aid will come off from the filter nets and will fall down.

Leave in recycle mode for about 15-20 min. Then, close the valve at filter outlet to the T-

105. Start P-105, open its delivery valve at filter inlet and close the valve on the P-106

delivery. Open the valve at the filter outlet discharging to the T-104 tank. P-106 and

AG-102 can be stopped.

The sulphur filtration is now started and we are filling the storage (T-104).

Check level in H-101 and in T-104. When level in T-104 is 80 %, switch the filter outlet

to T-104 to recycle back to H-101. When level in H-101 is at 80 %, close steam to the

melting section.

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Check the valves on the delivery of the pumps P-102 A/B to the furnace BR-101 are

closed.

Choose one pump P-102 and prepare its line for recycling liquid sulphur from the

storage T-104 to T-104 itself. Check all the other valves are closed.

Regulate the pump piston stroke length at the minimum value and start the pump.

Check pump amperage and increase gradually the piston stroke length to the plan start-

up value.

4.1.4) Exhausted Gas Section Start-Up

1) Electrofilter (ESP) F-301 preparation

Start BL-301

Regulate the steam to E-301 exchanger: TI-301 should be at about 80 °C

Check the total flow is distributed about equally to the four niches by the position of the

relevant valves.

Check the bottom discharge valve of F-301 is closed

Check the heating on the bottom is working.

Switch on the current to the ESP

2) Scrubber R-301 preparation

We suppose that the scrubber was operating at pH 7,2-7,5 and so it is now full of a

sulphite/sulphate solution at about 10% concentration.

Check that the level in the 30% caustic soda tank T-301 is at maximum value.

Check the level in R-301. It should be full.

Check the valve on the P-301 delivery to Na2SO3/Na2SO4 storage is closed.

Prepare the line to recycle the sulphite/sulphate solution from R-301 bottom to the top

column.

Start the pump P-301 and regulate the flow at about 20-25 m3/h.

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Check that the pH meter pHIT-301 is in automatic mode and set pH at 8 value.

Start the pump P-302.

4.1.5) Chilling Station Start-Up

Check level in T-101.

Choose one pump P-101, open valves on the suction and delivery. Check that the

valves of the other pump are closed.

Check the inlet/outlet valves to E-102 are open.

Start pump T-101 and check pressure on the delivery and level in T-101.

Start chilling unit following the relevant instructions setting the outlet temperature of

glycol solution at about –2°C.

Wait until the system has reached a steady condition.

4.1.6) Air Drying Section Start-Up

The start-up of this section requires the air compressor CO-101 start-up. The air fed by

the compressor has to pass through all the plant and has to be vented to the

atmosphere after the scrubber R-301. Passing through the converter this air will drag

SO2 and SO3 contained in the converter catalyst, even if we are in pre-heating phase.

That means the sulphur burning section, the converter, the sulphonator and the

exhausted gas section must be ready to accept this gas.

4.1.6.1) Drying Section

The PLC should show available the drier T-102 just ready to work. Check that the on-off

valves controlled by PLC are in the right position.

Steam to E-104 should be already to operate.

Cooling water to E-103 should be already to operate.

Steam to E-101 should be already to operate.

Check that the bottom discharge of E-102 is open.

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Check that the bottom discharge of F-102 is closed.

Start fan BL-101.

4.1.6.2) Sulphur Burning Section

Check level in the T-106. It should be at least more than 50%.

Choose one pump P-104 and prepare the line to feed water to the boiler E-107.

Check that all the valves on the other pump are closed.

Prepare the feeding line on the pump delivery.

Start the pump and fill the boiler.

Check that level regulation valve LIC-161 is in automatic mode.

Prepare the line on the steam discharge line.

The pressure regulation valve on the boiler E-107 should be already regulated at 12

bars.

4.1.6.3) Converter Section

Close the quench air to the first, second and third beds.

Close dilution air to F-104 demister.

Close the pre-heating air valve from E-106 outlet.

4.1.6.4) Sulphonator Section

Check level in T-201 .It should be at maximum value.

Check the emergency tank T-202 is full of LAB, its bottom valve is closed and the

pressure is about 0,5 bar (PI-202).

Check the inlet water make-up to the cooling circuit of the reactor is open.

Check the valves on the suction and delivery of the pump P-204 are open.

Start pump P-204 and check pressure and amperage. Check by the vent on the top

outlet water line there is no air inside the reactor.

Set TIRCAHL –201 in automatic mode and 2°C more than P-204 delivery temperature

(TI-202).

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Close valve from R-202 to LG-203 and LG-204.

Open valve from R-202 to T-204

Check the vent from T-204 to the exhausted gas collector is open

Check the discharge valve from CY-201 to LG-203 is open.

Choose one P-201 pump and prepare the line for feeding LAB to the reactor head.

Select one filter F-201.

Check the valve on the line from T-204 to the P-201 suctions is closed.

Check the recycling line from P-201 to T-201 is closed.

Start pump P-201 feeding the reactor at 50% plant capacity (1140 Kg/h). The LAB will

be collected in the T-204 tank.

When in the T-204 we have collected about 100 lts. (after about 4-5min.), open the

valve between T-204 and P-201 suction and close immediately the valve on the T-

201 bottom.

Now LAB is recycling from T-204 by P-201 through the reactor R-201.

Open the valve HS-201 on the gas line in the top of reactor R-201.

Check the level in T-203 (hydrolysis water).

4.1.6.5 ) Exhausted gas section

As soon as the pre-heating gas starts passing through the ESP, adjust the voltage to a

below value that at which the electrical discharges start.

The scrubber R-301 is ready to absorb the traces of SO2 escaped from the converter

during its pre-heating phase.

4.1.7) Furnace And Converter Pre-Heating Start-Up

Check the air valve before FR-162 to the furnace BR-101 is closed.

Check the air valve on the E-106 by-pass is closed.

Steam to E-105 should be already open.

Open the air valve at inlet of E-105.

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Check the valve from E-106 outlet to converter is closed.

Open completely the valve of the internal by-pass of the boiler E-107.

At this point the plant is ready to accept the hot gas for pre-heating furnace and

converter.

Open completely in manual mode PIRCAH-101.

Start compressor CO-101. Check amperage.

Close slowly the PIRCAH-101 control valve until FIRAL-161 shows about 3.000 Kg/h

(about 1.700m3/h)

The pressure of PIRCAH-101 shows the value correspondent to the system pressure

drop. Put it in automatic mode.

Check E-101 outlet temperature (about 130 °C).

Check E-102 outlet temperature (about 3°C).

Check that E-102 is discharging water condensate from the bottom.

Check the moisture after T-102 is at least –50°C.

Check temperature after T-102 is around 30°C.

Check temperature after E-105. It should be 130° or more.

Check that the whole drying regeneration system is properly working.

Start gradually to increase the air temperature at E-106 outlet operating by LCP 161

(TIRAH-163) of its electrical exchanger. Set the regulation at final stage around 500-

550°C.

Now the furnace starts to be heated and, in series, through the internal by-pass of the

boiler E-107, also the converter begins to heat up.

The pressure and the temperature in the boiler E-107 will gradually increase .When it

will reach 12 barg and about 191°C, the pressure regulation valve will begin to

discharge steam to the 6 bar net.

Because in this phase the boiler E-107 lowers the efficiency of the converter heating,

after the furnace has reached about 400 °C, open the by-pass valve of BR-101/E-107

directly to the converter.

This pre-heating phase should take (starting from room temperature) about 6

hours. The average hourly temperature increment should be roughly 80-90°C /h,

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bringing the furnace internal temperature and the first converter bed at about

450°C.

So the air pushed by the compressor CO-101 and dried through the drying system, is

heated in E-105/106, passes through the sulphur furnace and conversion section where

some traces of SO2/SO3 can be drawn. Then it enters the sulphonation reactor where

meets fresh LAB, which is recycling through the reactor head; finally reaches the

exhausted gas section where it is depurated from traces, if any, of SO2/SO3.

When the furnace and the converter beds have reached about 450°C the

preheating can be considered finished and the plant can be started.

PLANT CONDITIONS AFTER SULPHUR FURNACE AND CONVERTER

PREHEATING

Compressor CO-101 is running. The pressure of PIRCAH-101 will sign the value

correspondent to the system pressure drop and the FIRAL-161 will show 3.000 Kg/h

(about 1.700 m3/h).

Chiller CH-101 is running, cooling the air at about 2-3°C.

Air drying section is running.

Sulphur melting section T-104 is full of liquid sulphur; P-105 is running recycling back

through the filter F-105 to H-101, sulphur melt is stopped, P-102 is running and

recycling back to T-104.

Sulphur furnace is hot and E-107 is working. Preheating phase is still operating.

Converter is hot and BL-102 is running. Preheating phase is still operating.

Sulphonation reactor LAB is recycled from T-204 to reactor head at 50% of plant

capacity, the cooling is working.

Exhausted gas treatment: ESP is working, R-301 is working and pH is around 8.

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4.2 ) PLANT START-UP

We decide to start at 50% plant capacity.

Start-up flow rate 1500 Kg/h of LABS.

4,5% by volume SO3 in the reaction gas.

Because the sulphonation reaction is normally managed and controlled by the analysis

of sulphonic acid at reactor outlet (acidity), the start-up parameters are fixed in not

rigorous way being they in second time adjusted following the analysis results.

We assume:

Air temperature = 30°C

Air pressure = 0,5 Kg/cm2

Air density 0° and 760mm.Hg = 1,29 kg/m3

Temperature correction factor = (273+30) / 273 = 1,11

Pressure correction factor = 1,0/1,5 = 0,67

Total correction factor = 1,11 X 0,67 = 0,74

From material balance we get:

Plant flow rate 50% of max. capacity = 1500 Kg/h of LABS

Sulphur = 152 Kg/h

LAB = 1140 Kg/h

Total air = 3223 Kg/h /1,29 x 0,74 = 1849 m3/h

Combustion air = 1860 Kg/h/1,29 x 0,74 = 1067 m3/h

Air regulation

The air flow rate regulation is realized operating on the compressor vent valve installed

in the compressor delivery. Operating with the PIRCAH-101, the valve PCV-101 drives

automatically part of the air compressed by CO-101 to the furnace and converter

passing through the calibrated flange FIRAL-161 where the total air is so measured.

The air pressure signed by PIRCAH-101 is that corresponding to the pressure drop of

the down stream system for that flow rate.

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Put in manual mode PIRCAH-101 and, operating on the pressure set, decrease the total

air flow rate at about 1067 mc/h (FIRAL-161)

Sulphur regulation

The liquid sulphur flow rate is regulated by the piston stroke length of the pump P-102.

Regulate the piston stroke length of the P-102 at 150 Kg/h by calibration curve.

LAB regulation

The LAB flow rate is controlled by the mass flow meter FIRCAL-201, which actuates the

inverter of pump P-201.

Regulate FIRCAL-201 at 1140 Kg/h

IMPORTANT RULES FOR THE SULPHONATION REACTION:

1) THE QUANTITY OF SO3 NECESSARY FOR SULPHONATING A CERTAIN

AMOUNT OF LAB IS CONTROLLED BY THE ANALYSIS OF ACIDITY

CHECKED PERIODICALLY AT THE REACTOR OUTLET.

THE ACIDITY IS THE QUANTITY OF SULPHONIC ACID + H2SO4

CONTAINED IN THE PRODUCT AT THE REACTOR OUTLET.

FOR PRACTICAL REASONS THE ACIDITY IS EXPRESSED AS THE

MILLIGRAMS OF KOH NECESSARY FOR NEUTRALIZING THE ACIDITY

CONTAINED IN 1 GR. OF PRODUCT.

FOR 98% SULPHONIC ACID AND 1% H2SO4, WHICH CAN BE RIGHT

VALUES OF SULPHONATION, THE FINAL ACIDITY IS IN THE RANGE OF

180.

2) WHEN THE RIGHT RATIO SO3/ LAB HAS BEEN REACHED, SMALL

ADJUSTMENTS CAN BE DONE VARYING THE LAB FLOW RATE. NEVER

MOVE THE SULPHUR FLOW RATE.

3) WHEN THE PLANT OUTPUT HAS TO BE INCREASED, FIRST INCREASE

THE AIR FLOW RATE, THEN LAB AND FINALLY SULPHUR.

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WHEN THE PLANT OUTPUT HAS TO BE DECREASED, FIRST DECREASE

SULPHUR , THEN LAB AND FINALLY THE AIR FLOW RATE.

ABSOLUTELY AVOID THE SO3 EXCESS WHICH BURNS LAB GIVING BLACK

COLOUR AND CARBON MATTERS WHICH OBLIGE TO STOP THE PLANT AND

TO CLEAN THE REACTOR HEAD.

4.2.1) Sulphur furnace

Stop preheating: close steam to E-105 and cut the power to E-106

Close the hot air valve to the converter (by-pass of BR-101/E-107)

Open the valve on air line to BR-101 before FIR-162.

Close the air inlet valve to E-105.

Regulate FIR-162 at about 1067 mc/h.

Open the valve on the delivery line of P-102 to the furnace BR-101 and then close

the valve on the recycling line to T-104.

Check through the sight glass SG-161 when liquid sulphur is falling down on the

internal bricks and if it ignites immediately.

The furnace temperature will increases rapidly: check TIRAH-160; when it approaches

to 750 °C, regulate FIR-162 to maintain it. Remember that the temperature increases

when the SO2 concentration increases and vice versa. If necessary increase the air

pressure operating on PIRCAH-101.

Regulate the gas outlet E-107 temperature at 450 °C, operating with the by-pass valve

of the boiler: closing the by-pass the temperature should decrease; opening it the

temperature should increase.

Check E-107: level, pressure, feeding pumps.

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4.2.2) Converter section

As soon as the SO2 concentration increases in the gas stream, the first bed outlet

temperature (TIRAH-182) increases, up to about 615 °C.

Start to open cooling air to the first bed outlet bringing back the temperature to 440 °C.

For this operation the needed total air (FIRAL-161) will increase. Thus, increase the

total air (FIRAL-161) operating on PIRCAH-101 to satisfy the quantity of needed air,

keeping constant FR-162.

Also in the second bed the temperature will increase up to about 468 °C (TIR-184).

Start to open cooling air to the second bed outlet bringing back the temperature to

440°C. Increase the total air flow rate as before.

In the third bed the temperature will arise up to about 445°C (TIR-186), but, opening the

cooling air, it will be brought back to 440°C. Increase the total air flow rate as before.

In the fourth bed, if the oxidation of SO2 to SO3 has been managed properly, the

temperature at the outlet will be around 425°C.

Check at this point the flow rate of the total air signed by FIRAL-161: It should be equal

or less than value foreseen by the material balance. If it is less, add the remaining air

through the line between E-109 and F-104. So open the relevant air valve to the F-104

and increase the total air flow rate up to the foreseen value actuating the PIRCAH-101.

Check flow rates and temperatures adjusting them, if necessary.

As soon as the temperature at converter outlet starts to increase, open the valve on the

BL-102 delivery cooling E-108 and E-109.

At E-108 outlet the process gas should maintained at about 250°C, while at the outlet of

E-109 the gas temperature should be around 70 °C

At this point the total air necessary for diluting the SO3 at 4,5% concentration is

distributed among:

1) The furnace BR-101, where its quantity is regulated by the furnace

temperature (750°C).

2) The three quench airs to the converter, where also is regulated by the

temperature at second, third and fourth bed inlets.

3) The rest being sent as final dilution before F-104.

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4.2.3) Sulphonation Reactor

As soon as sulphur starts to burn in the furnace, it generates SO2 and then SO3 through

the converter.

The converter temperatures start to increase in the four beds.

Starting from this time, we maintain LAB in recycle for some minutes, checking the

acidity continuously.

When the acidity is around 50/60, open the bottom valve of T-201 and close the T-204

bottom valve.

Now we are feeding fresh LAB to the reactor head, always collecting the reactor bottom

in the T-204 tank.

Check continuously the acidity.

After 20’ the sulphonation reaction should have reached 70-80 and the reactor outlet

can be switched to LG-203 and R-203.

In this way we will have collected in T-204 about 500 lts. of a mixture LAB/LABS about

50/50 which will be recovered little by little later.

Check continuously the acidity.

Prepare the suction and delivery line of the P-202 pump for sending LABS to the

storage.

Open water to R-203 jacket and then also steam just to heat the jacket for maintaining

the LABS at about 50°C.

Close the outlet valves of R-203 leaving LABS coming out from the higher outlet.

Start R-203 stirrer.

When LABS overflows from R-203, start P-202 and regulate the level by LIC-201.

Check always acidity.

The final acidity should be around 170/180. To adjust this value operates only

with small variations of the LAB flow rate followed by acidity checks. Never touch

the sulphur flow rate.

Open suction and delivery valves of pump P-203, start the pump and regulate FI-201 at

about 7 lts/h (0,05% ).

Open cooling water to E-202. TI-207 should be around 30/35°C.

Now the product is going to the storage.

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4.2.4) Exhaust Gas Treatment

4.2.4.1 Electrostatic precipitator

The operation of the electrofilter is very simple.

The gas is passing now through the filter.

Adjust the voltage to a value a little below that at which the electrical discharges start.

During the operation if there are frequent discharges or even a continuous arc, the

voltage drops and hence the filtering efficiency decreases: the voltage must be reduced

by hand until the discharges cease.

On the other hand, an attempt should be made from time to time to increase voltage in

order to restore filtering efficiency, which may be reduced if the filter is dirty.

During the operation the ESP is automatically cut out, ceasing to operate, and gives an

acoustic alarm if:

-the transformer oil temperature exceeds the permissible level

-there are frequent high intensity discharges (sign of excessively high voltage).

-voltage at filter is too low (sign of short-circuit in the filter).

-the filter current is too high.

4.2.4.2 Scrubber

SO2 contained in the exhausted gas is now arriving to the scrubber.

From material balance we get that at 50% capacity the plant produces 17,7 x 0,5 = 8,85

Kg/h of 100% sulphite which at 10% concentration gives 88,5 Kg/h (about 80 lt.) of

solution which we must be sent to the storage. So regulate manually the FI-302 at about

this value, transferring this hourly amount to the storage.

Set back the ph to the previous value (7,2-7,5 ): P-302 will stop and it will start again

when the ph will reach this value.

4.2.5 ) Interlock System

The interlock, which was excluded at the beginning of the start-up phase, must now be

again included.

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4.3 ) CAPACITY INCREASE

Now the plant start up can be considered finished but we have to reach the maximum

capacity, which is one of the main targets of the plant.

We suggest remaining at 50% capacity for 2-3 hours, and then proceed to increase

gradually the capacity.

The major part of process parameters will not change much, especially temperatures

and pressures; while the flow rates will change generally proportionally.

We report here the range of the main process parameters you should meet in the plant

management writing in red colour those which change substantially due to capacity

change:

AIR COMPRESSION AND DRYING P AND I 1021

TI-105 CO-101 delivery 130-150 °C

PI-102 after E-101 0.5-1,0 bar

TI-103 before E-102 20-50 °C

PI-103 after E-102 0.5-1,0 bar

TI-104 after E-102 2,0-5,0 °C

TIRAHL-101 after F-102 2,0-5,0 °C

MIRAHL-101 after T-102 -30/-80 °C

PIRCAH-101 after T-102 0,3-0,9 bar

PI-104 after T-102 0,3-0,9 bar

TIR-104 after T-102 20-50 °C

TIR-102 BL-101 suction 20-230 °C

TIR-103 after E-103/104 20-230 °C

TI-106 BL-101 suction 20-250 °C

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CHILLING UNIT P AND I 1022

TIR-121 after CB-101 -2 / +0,5 °C

TIR-122 before T-101 +5 / +10 °C

TI-121 T-101 tank +5 / +10°C

PI-121/122 delivery P-101 2-5 bar

SULPHUR MELTING AND FILTRATION P AND I 1023

TIAL-141 sulphur melter H-101 145-155 °C (?)

TI – 142 T-104 tank 145-155 °C

SULPHUR BURNING P AND I 1024

FIRAL-161

FIR-162

total air from T-102

combustion air

50-100% capacity

50-100% capacity

1849-3698 m3/h

1067-2134 m3/h

Piston stroke length P-102 sulphur pump 50-100% capacity 152-304 Kg/h

FIRAL-161 air in preheating phase 3000 m3/h

TI-161 after E-105 in preheating phase 130-150 °C

TIRAH-163 after E-106 in preheating phase 500-600 °C

TR-162 BR-101 top 650-750 °C

TIRAH-160 BR-101 outlet 700-800 °C

TIRAH-161 BR-101 outlet 700-800 °C

TR-164 E-107 outlet 440-460 °C

PI-160 steam from E-107 11-12 bar

PI-163 steam from E-107 11-12 bar

PI-164 steam from E-107 after reduction 5,5-6,5 bar

PI-161/162 P-104 delivery 12-15 bar

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SO2/SO3 CONVERSION - P AND I 1025

PI-161 before converter R-101 0.5-0,4 bar

TIR-181 first bed inlet 445-455 °C (Monsanto 450°C)

TIRAH-162 first bed outlet 600-620 °C (Monsanto 614°C)

TIR-183 second bed inlet 435-445 °C (Monsanto 440°C)

TIR-184 second bed outlet 460-470 °C (Monsanto 468°C)

TIR-185 third bed inlet 435-445 °C (Monsanto 440°C)

TIR-186 third bed outlet 440-450 °C (Monsanto 444°C)

TIR-187 fourth bed inlet 420-430°C (Monsanto 425°C)

TIR-188 fourth bed outlet 420-430°C (Monsanto 426°C)

PI-182 converter R-101 outlet 0,45-0,35 bar

TI-182 process after E-108 200-250°C

TI-185 process after E-109 70-80 °C

TI-181 cooling air after E-108 250-350°C

TI-184 cooling air after E-109 120-170°C

TI-183 air to regeneration 200-220°C

PI-183 after F-104 0,4-0,3 bar

44

SULPHONATION REACTION – P and I 1026

TI-201 before F-202 55-65 °C

PI-201 before F-202 0,4-0,3 bar

PI-202 T-202 top 0,5 bar

PI-210 after T-210 0,5 bar

TIRAHL-202 process gas reactor head 55-65°C

PI-203 process gas reactor head 0,35-0,25 bar

TI-210 R-201 cooling water upper outlet 29-33°C

TI-211 R-201 cooling water lower outlet 29-30°C

TIRCAHL-201 R-201 cooling water outlet 29-31°C

PI-206 P-204 delivery 3-6 bar

TI-202 P-204 delivery 28-30°C

TI-209 T-201 tank 20-40°C

PI-204 /205 P-201A/B delivery 1-2 bar

FIRCAL-201 LAB to reactor top (50-100 % capacity) 1140-2280 K/h

TI-205 R-201 bottom 30-50 °C

TI-204 R-203 aging 40-50°C

PI-209 Vent to exhaust gas treatment 0.2-0.15 bar

TI-208 Vent to exhaust gas treatment 40-50 °C

PI-207 P-202 delivery 3-10 bar

TI-206 After MX-201 50-55°C

TI-207 After E-202 30-40°C

FI-201 P-203 delivery (50-100% capacity) 7-15 lt./h

PI-206 P-203 delivery 3-5 bar

45

EXHAUST GAS TREATMENT – P AND I 1027

Adjust the voltage F-301 as per previous instructions

TI-301 after E-301 80-90 °C

PI-301 after F-301 0.1- 0,05 bar

TI-302 after F-301 40-50 °C

FI-301 P-301 recycle 20-30 m3/h

FI-302 P-301 delivery 80-160 lt./h

PhICAL after MX-301 7,2-7,5

TI-303 R-301 40-50°C

Capacity increase from 50% to 100%

Proceed by steps, increasing the capacity by 10% each step.

The total capacity increase time should take about two-three hours.

50% total air 1849 m3/h

combustion air 1067 m3/h

sulphur 152 Kg/h

LAB 1140 Kg/h

60% total air 2219 m3/h

combustion air 1280 m3/h

sulphur 182 Kg/h

LAB 1368 Kg/h

70% total air 2588 m3/h

combustion air 1494 m3/h

sulphur 213 Kg/h

LAB 1596 Kg/h

46

80% total air 2958 m3/h

combustion air 1707 m3/h

sulphur 243 Kg/h

LAB 1824 Kg/h

90% total air 3328 m3/h

combustion air 1921 m3/h

sulphur 273 Kg/h

LAB 2052 Kg/h

100% total air 3698 m3/h

combustion air 2134 m3/h

sulphur 304 Kg/h

LAB 2280 Kg/h

So now proceeding as per priority just before reported, we start to increase the plant

output as follows:

From 50% capacity to 60% capacity:

1) Increase the total air flow rate from 1849 to 2219 m3/h, operating with PIRCAH 101.

2) Increase the LAB flow rate from 1140 to 1368 Kg/h operating with FIRCAL 201.

3) Increase the combustion air from 1067 to 1280 m3/h operating with the manual valve

before FIR-162.

4) Increase sulphur feed to the furnace from 152 to 182 Kg/h operating with the piston

stroke length of the P-102.

5) Maintain the outlet gas temperature from furnace at 750°C. If necessary readjust the

combustion flow rate.

6) Check the acidity is in the range of 170-180. If necessary readjust the LAB flow rate.

7) Increase proportionally the hydrolysis water by pump P-203 (FI-201).

47

8) Increase proportionally FI-302 on the pump P-301 delivery).

9) If necessary, increase the voltage of the ESP.

10)Remain at this capacity for about 20 minutes.

11)The following others key parameters will change and must be brought back to the

previous value:

- Air temperature to driers TIRAHL-101 (increase the cooling effect of the

chiller).

- SO2/air temperature to converter TR-164 (regulate the internal by-pass of the

E-107).

- All the converter beds temperature (regulate the quench air to the beds).

- Outlet process temperatures of E-109(regulate the cooling air of the fan BL-

102).

- Aging tank temperature (TI-204) (increase steam in the jacket water bath of

R-203, if necessary).

- LABS temperature to storage (TI-207) (increase cooling water to E-202).

After about 20 minutes proceed to the next step from 60% to 70% operating in the same

way, assuming that the quantity of air, LAB and sulphur are just as shown before.

The same procedure up to 100% capacity.

If necessary, increase stand-by among each step.

When 100% capacity has been reached, verify that all the plant parameters listed

before in the PLANT START-UP chapter are included in the indicated range. If some of

them are out of their range, report it to the plant manager.

After some experience of plant start-up, we believe it could be convenient to

increase the plant capacity from 50% directly to 100% or to the final chosen

capacity.

48

5) NORMAL RUN AND CONTROLS

As soon as the plant has reached the 100% capacity, or, in any case, has reached the

capacity judged final in that moment, the plant enter normal run.

In this phase all the plant parameters should be stable and regular.

In details and for the key points:

P and I 1021 air compression and drying

- compressor delivery pressure must be constant at value maximum reached which

corresponds to the pressure drop of the system at that capacity. It should be 0,9 bar

max.

PIRCAH-101 should be in automatic mode.

- air temperature before driers (TIRAH-101) must be stable at 2-3 °C

- moisture meter (MIRAHL-101) should sign –40°C min.

- drying system must work automatically. Every 8 hours the driers should invert their

function:

Operation and regeneration.

- E-102 bottoms must discharge regularly the condensate.

- E-104 has to have the steam line close.

During the regeneration heating phase the hot air coming from E-108/9 should be

sucked regularly by the fun BL-101 .If necessary close a little the valve on the vent line.

P and I 1022 refrigerating group

The glycol temperature (TIR-121) should be stable.

P and I 1023 sulphur melting and filtration

- sulphur melting should start again. So open steam to the melting coils.

Check level in H-101 and switch the F-105 outlet from H-101 recycle to T-104

49

- Check the level in T-104

P and I 1024 sulphur burning

- FIRAL-161 and FIR-162 should be stable and constant.

- By SG-161 and SG-162 check sulphur is flowing regularly and is burning completely

in the upper chamber.

- TIRAH 160/161 must be stable and constant.

- LICAHL-161 must be stable and constant at prefixed value.

- PIRCAH-160 must be stable and constant.

P and I 1025 SO2/SO3 conversion

- Converter beds temperatures: after a first adjustment time these temperatures must

be straight and parallel lines.

-TI-185 should be around 70 °C

P and I 1026 reaction and aging

- Acidity must be checked at the beginning every hour for the first 8-10 hours after

start-up. Then, if the key parameters of the plant are constant and regular, it can be

checked every two hours.

Of course, if necessary, a re-adjustment of LAB flow rate should be done.

-Start to check free acidity (H2SO4), sulphonic acid and Klett colour every 4 hours

-FIRCAL-201 should be stable.

-TIRCAH-201 should have about 2°C more than TI-202.

-TI-210 should not be higher than TI-201. If necessary, operate with the relevant manual

valves on the pump delivery.

-Level LIC-201 must be absolutely constant.

In this phase should be necessary to proceed to recover the partially sulphonated

LAB collected in T-204, because the level in this tank should be kept enough low

to receive, in case of emergency, the content of the tank T-202.

50

On the other hand, the T-204 tank should not be completely empty, because in

case of emergency it could be useful to have available some LAB to be promptly

recycled.

100 lt. always in the tank is advisable.

P and I 1027 spent gas cleaning

-F-301: be sure that the voltage is at maximum value before getting arc discharges.

-Open the bottom valve: leave it opened only if gas is not going out.

-pHCAL-301 should be constant.

-FI-301 and FI-302 should be constant.

-Check that LCV-301 is maintaining constant the level in R-301

-Check that an almost not visible plume is going out from the R-301 stack.

THE OPERATOR MUST PERIODICALLY DO THE FOLLOWING CHECKS AND

WRITE THE RESULTS WITH CARE IN THE RELEVANT CONTROL CHART.

Although today the chemical plants are rich of automatic controls, alarms and interlocks

which of course assure a safe plant running and a good operator safety, we think that in

no case the operators should disregard the compilation of the daily control chart.

This service, besides the reading of many local indications not reported to the panel

board, obliges the operator to go on site and consequently to inspect the equipment

pointing out many plant signals as not normal noises, not usual vibrations, leakages of

liquids and gases and so on, which would not be noted from panel board.

For these reasons we recommend the daily chart compilation, following the hourly

timing here shown:

51

AIR COMPRESSION AND DRYING P AND I 1021

ITEM WHERE EXPECTED VALUES WHEN

TI-105 CO-101 delivery 130-150 °C every two hours

PI-102 after E-101 0.5-1,0 bar “ “ “

TI-103 before E-102 20-50 °C “ “ “

PI-103 after E-102 0.5-1,0 bar “ “ “

TI-104 after E-102 2,0-5,0 °C “ “ “

TIRAHL-101 after F-102 2,0-5,0 °C every one hours

MIRAHL-101 after T-102 -30/-80 °C “ “ “

PIRCAH-101 after T-102 0,3-0,9 bar “ “ “

PI-104 after T-102 0,3-0,9 bar every two hours

TIR-104 after T-102 20-50 °C “ “ “

TIR-102 BL-101 suction 20-230 °C “ “ “

TIR-103 after E-103/104 20-230 °C “ “ “

TI-106 BL-101 suction 20-250 °C “ “ “

CHILLING UNIT P AND I 1022

TIR-121 after CB-101 -2/+0,5 “ “ “

TIR-122 before T-101 +5 / +10 °C “ “ “

TI-121 T-101 tank +5 / +10°C “ “ “

PI-121/122 delivery P-101 A/B 2-5 bar “ “ “

SULPHUR MELTING AND FILTRATION P AND I 1023

TIAL-141 sulphur melter H-101 145-155 °C every one hour

TI – 142 T-104 tank 145-155 °C “ “ “

LI- 111 sulphur melter H-101 30-70 % “ “ “

52

SULPHUR BURNING P AND I 1024

FIRAL-161 total air from T-102 1849-3698 m3/h every one hour

FIR-162 air to BR-101 1067-2134 m3/h “ “ “

Piston stroke length P-102 sulphur pump 150-300 Kg/h “ “ “

FIRAL-161 air in preheat.phase 1940-2710 Nm3/h “ “ “

TI-161 after E-105 in preheat.phase 130-150 °C “ “ “

TIRAH-163 after E-106 in preheat.phase 500-600 °C “ “ “

TR-162 BR-101 top 650-750 °C every two hours

TIRAH-160 BR-101 outlet 700-800 °C every one hour

TIRAH-161 BR-101 outlet 700-800 °C “ “ “

TR-164 E-107 outlet 440-460 °C “ “ “

PI-160 steam from E-107 11-12 bar every two hours

PI-163 steam from E-107 11-12 bar “ “ “

PI-164 steam from E-107 after red. 5,5-6,5 bar “ “ “

PI-161/162 P-104 delivery 12-15 bar every one hour

LG-161 A/B E-107 70% min. “ “ “

LICAHL-161 E-107 70% min “ “ “

53

SO2/SO3 CONVERSION - P AND I 1025

PI-161 before converter R-101 0,5-0,4 bar every two hours

TIR-181 first bed inlet 455 °C (Mons.450°C) “ “ “

TIRAH-162 first bed outlet 600-620 °C (Mons. 614°C) “ “ “

TIR-183 second bed inlet 435-445 °C (Mons. 440°C) “ “ “

TIR-184 second bed outlet 460-470 °C (Mons.468°C) “ “ “

TIR-185 third bed inlet 435-445 °C (Mons.440°C) “ “ “

TIR-186 third bed outlet 440-450 °C (Mons.444°C) “ “ “

TIR-187 fourth bed inlet 420-430°C (Mons.425°C) “ “ “

TIR-188 fourth bed outlet 420-430°C (Mons. 426°C) “ “ “

PI-182 converter R-101 outlet 0,45-0,35 bar “ “ “

TI-182 process after E-108 200-250°C “ “ “

TI-185 process after E-109 70-80 °C every one hour

TI-181 cooling air after E-108 250-350°C every two hours

TI-184 cooling air after E-109 120-170°C “ “ “

TI-183 air to regeneration 200-220°C “ “ “

PI-183 after F-104 0,4-0,3 bar “ “ “

54

SULPHONATION REACTION – P and I 1026

TI-201 before F-202 55-65 °C every two hours

PI-201 before F-202 0,4-0,3 bar “ “ “

PI-202 T-202 top 0,5 bar “ “ “

PI-210 after T-210 0,5 bar every four hours

TIRAHL-202 process gas reactor head 55-65°C every two hours

PI-203 process gas reactor head 0,35-0,25 bar “ “ “

TI-210 R-201 cooling water up.outlet 29-33°C every hour

TI-211 R-201 cooling water low.outlet 29-30°C every hour

TIRCAHL-201 R-201 cooling water outlet 29-31°C every two hours

PI-206 P-204 delivery 3-6 bar “ “ “

TI-202 P-204 delivery 28-30°C “ “ “

TI-209 T-201 tank 20-40°C “ “ “

PI-204 /205 P-201A/B delivery 1-2 bar “ “ “

FIRCAL-201 LAB to reactor top 1125-2250 K/h every hour

TI-205 R-201 bottom 30-50 °C every two hours

TI-204 R-203 aging 40-50°C every hour

PI-209 vent to exhaust gas treat. 0.2-0.15 bar every two hours

TI-208 vent to exhaust gas treat. 40-50 °C “ “ “

PI-207 P-202 delivery 3-10 bar “ “ “

TI-206 after MX-201 50-55°C “ “ “

TI-207 after E-202 30-40°C “ “ “

FI-201 P-203 delivery 7-15 lt./h every hour

PI-206 P-203 delivery 3-5 bar every two hours

LG-201 T-202 70% min. every four hours

Acidity after LG-203 170-180 every hour

LG-203 colour normal every hour

LIC-201 after LG-204 normal “ “ “

F-202 bottom discharge empty ones a day

55

EXHAUST GAS TREATMENT – P AND I 1027

Plume at R-301 outlet stack almost not visible every hour

Voltage F-301 as per previous instructions ones a day

TI-301 after E-301 80-90 °C every two hours

PI-301 after F-301 0.1- 0,05 bar “ “ “

TI-302 after F-301 40-50 °C “ “ “

FI-301 P-301 recycle 20-30 m3/h “ “ “

FI-302 P-301 delivery 80-160 lt./h “ “ “

PhICAL after MX-301 7,2-7,5 every hour

TI-303 R-301 40-50°C every two hours

56

6) NORMAL SHUT-DOWN

With “normal shut-down” we intend the programmed plant shut-down for production or

maintenance reasons.

The normal shut-down can be for short time or for long time or, more specifically, for

about few hours / one-two days or for several days.

The difference between the two types of shut- down is as follows:

a) shut-down for short time

- All the machinery is shut.

- The sulphur furnace and converter are kept hot as much as possible to allow a shorter

pre-heating time. So the purge by process air should be short.

- All the tanks and equipment remain full of liquids contained at the shut–down moment,

if not necessary for maintenance reasons.

- Liquid sulphur section must be kept hot by steam.

After all the machinery is stopped the situation of utilities should be the following:

- Power should be on

- Cooling water can be stopped

- Instrumentation air should be working

- Steam should be working

b) shut-down for long time

- All the machinery are shut.

- Sulphur furnace and converter are purged and cooled by air process.

57

- The level of liquid sulphur equipment must be minimized before shut down. The

remaining sulphur can be left solidify closing steam to the section.

- All the other tanks and equipment must be emptied but glycol tank T-101, if not

necessary for maintenance reasons.

- After all the machinery is stopped the situation of utilities should be the following:

o Power can be off.

o Cooling water can be stopped.

o Instrumentation air can be stopped.

o Steam can be stopped.

6.1) SHUT-DOWN PROCEDURE FOR SHORT TIME

- Cut sulphur to the furnace BR-101: open the delivery valve of P-102 to T-104 and

close the valve to the furnace.

- Switch the reactor bottom from R-203 to T-204.

- After 3-4 minutes connect the P-201 suction with T-204 and close the bottom valve of

T-201: so LAB is now recycling to the reactor head.

- Stop the hydrolysis pump P-203.

- Leave the compressor running for about 15 minutes, purging so the furnace, the

converter and all the plant from the main quantity of SO2 and SO3.

- Stop sulphur melting and, if sulphur filtration was running, switch back from the filter

outlet to the melter H-101.

- Close the delivery valve of P-301 to the sulphite/sulphate storage.

- Operating on the PIRCAH-101 open gradually the vent valve on the compressor CO-

101 delivery.

- Stop the compressor CO-101 and close the automatic valve HS-201 on the reactor

head.

- Stop the chiller CH-101 and the glycol circulation pumps.

- Stop the recycling pump P-301 and P-302 on the R-301

58

- Stop BL-101 , BL-102 and BL-103

- Close the steam to E-301.

- Stop the pump P-201 which is recycling to the reactor head.

- Stop the sulphur pump P-102.

- Stop the feeding pump P-104 to E-107.

- Stop the cooling pump P-204 to reactor.

- Stop the extraction pump P-202.

- Cut the current to ESP F-301.

6.2) SHUT-DOWN PROCEDURE FOR LONG TIME

6.2.1 ) Preliminary Operations In View Of A Long Time Shut-Down

The plant shut-down in such a case should be preceded by a production program

finalized to reduce as much as possible the liquid level in some tanks and equipment.

Sulphur section.

The melter H-101 level must be minimized up to height of the suction of P-105 pump; T-

105 level must be reduced up to height of suction of P-106 pump; the feed of sulphur to

the furnace must be stopped when the level in T-104 reaches the minimum alarm.

Reaction section

Eventual off specification LAB contained in the T-204 tank should be totally recovered

before shut-down.

59

6.2.2 ) Shut-Down Procedures

- Cut sulphur to the furnace BR-101: open the delivery valve of P-102 to T-104 and

close the valve to the furnace.

- Switch the reactor bottom from R-203 to T-204.

- After 3-4 minutes connect the P-201 suction with T-204 and close the bottom valve of

T-201: so LAB is now recycling to the reactor head.

- Stop the hydrolysis pump P-203.

- Leave the compressor running for about 1 hour, purging so deeply the furnace, the

converter and all the plant from SO2 and SO3.

- Stop sulphur melting and, if sulphur filtration was running, switch back from the filter

outlet to the melter H-101.

- Close the delivery valve of P-301 to the sulphite/sulphate storage.

- Operating on the PIRCAH-101 open gradually the vent valve on the compressor CO-

101 delivery.

- Stop the compressor CO-101 and close the automatic valve HS-201 on the reactor

head.

- Stop the chiller CH-101 and the glycol circulation pumps.

- Stop the caustic soda feeding pump P-302 to R-301.

- Stop BL-101, BL-102 and BL-103.

- Stop the pump P-201 which is recycling to the reactor head.

- Stop the sulphur pump P-102.

- Stop the feeding pump P-104 to E-107.

- Stop the cooling pump P-204 to reactor.

- Empty R-203 opening the bottom valve.

- Stop the extraction pump P-202.

- Cut the current to ESP F-301.

- Close process water to R-301.

- Transfer all the content of R-301 to the storage, if necessary.

- Stop P-301.

60

6.2.3) Tanks And Equipment Which Can Be Left With Their Liquids, If Not

Necessary To Have Them Empty For Maintenance

- T-101 glycol tank.

- T-106 soft water tank.

- T-201 LAB tank.

- T-204 off spec. LAB tank.

- T-203 hydrolysis water tank.

- T-301 caustic soda tank.

If for some reasons these tanks should be emptied, we suggest to discharge their

content in drums to be recovered later (by portable pump), but T-106 and T-203 which

can be discharged to the sewer.

61

7) EMERGENCY SHUT-DOWN

The causes which can bring the plant to an emergency shut-down are as follows:

1) power failure

2) instrument air failure

3) cooling water failure

4) interlock intervention for these anomalous situations :

a) High pressure air compressor CO-101 delivery (PAH-101).

b) High temperature air compressor CO-101 delivery (TAH-101).

c) High temperature gas outlet furnace BR-101 (TIRAH-161).

d) Low-low level in E-107 boiler (LALL-161).

e) High pressure E-107 boiler steam side (PAH-160).

f) BL-102, cooling fun after conversion, failure.

g) Feed of LAB to reactor failure (FIRCAL-201).

5) Other emergency situation (SO2/SO3 leakages, pipes sudden breakdown, ecc.).

7.1) POWER FAILURE

- All the machinery is stopped. When the power will be back all the machinery has to

be restarted.

- Cooling water pressure is down.

- Steam pressure is down.

- Instrumentation air should be available for few minutes (about 4).

- The SO3/air valve on the reactor inlet UV-201 closes automatically.

- The bottom valve of T-202 tank opens automatically and LAB flows into reactor

(HS-202).

- The operator must immediately switch the reactor outlet from LG-203 to T-204

62

- PCV-101 on the compressor vent line opens completely.

- TCV-201 on reactor cooling water line opens completely.

- LCV-161 on E-107 regulation level close completely

- KV from 101 to 106 valves on air dryers / regeneration system remain in the same

position; KV from 107 to 111 close.

- When the power has been restored proceed with normal start-up procedures,

starting first the utilities.

7.2) INSTRUMENT AIR FAILURE

- The SO3/air valve on the reactor inlet UV-201 closes automatically and vent valve

on the compressor delivery PCV-101 opens completely.

- Sulphur pump P-102 stops immediately.

- The bottom valve of T-202 tank opens automatically and LAB flows to the reactor.

- The operator must immediately switch manually the reactor outlet from LG-

203 to T-204

- TCV-201 opens completely.

- LCV-161 opens completely.

- Stop compressor CO-101.

- Of course, some sections and machinery are still running.

- As soon as the instrument air has been restored, start the plant again following the

normal procedures.

7.3) COOLING WATER FAILURE

The lack of cooling water is not considered a weighty event, even if this can cause plant

shut-down in short time. The cooling water failure does not stop automatically the plant.

Generally the lack of cooling water should be due to out of service of cooling tower

feeding pump which is working in this moment.

63

After the alarm of low pressure on the feeding cooling water line, the operator should

immediately go to cooling tower site and start the stand–by pump. This operation should

bring back the plant to normality in few minutes without any sensible damage of

production.

Any way, for more complete information, we remind that the lack of cooling water could

temporarily cause the following effects:

- Temperature rises at driers outlet (due to lack of cooling water to E-101).

- Moisture rises at driers outlet (same cause).

- Temperature rises at the outlet of E-103 regeneration exchanger (due to lack of

cooling at the same).

- Temperature rises in the reactor cooling circuit (due to lack of cooling water make-

up).

- Increase of Klett colour in the product (same reason).

7.4) INTERLOCK INTERVENTION

7.4.1) If PAH or TAH-101 is on, the following consequence will be actuated:

- Air compressor CO-101 stops.

- Sulphur pump P-102 stops.

- UV-202 opens

- Switch reactor bottom from LG-203 to T-204.

- Put the pump P-102 recycling from T-204 to reactor head.

When the shut-down causes have been removed, star again compressor, fresh LAB

and sulphur.

7.4.2) If TIRAH-161/LALL-161/PAH-160 are on or BL-102 is off, the following

consequence will be actuated:

64

- Sulphur pump P-102 stops.

- Air compressor vent PCV-101 opens completely.

- SO3/air valve (UV-201) on reactor head closes.

- UV-202 opens.

- The operator must switch the reactor bottom from LG-203 to T-204.

- Put the pump P-102 recycling from T-204 to reactor head.

When the shut-down causes have been removed, start again compressor, fresh LAB

and sulphur.

7.4.3) If FIRCAL-201 is off, the following consequence will be actuated:

- Bottom valve of the emergency tank UV-202 opens.

- Stop sulphur pump P-102.

- The operator must switch the reactor bottom from LG-203 to T-204.

- Put the pump P-102 recycling from T-204 to reactor head.

- Open completely PCV-101 (compressor vent).

- Close UV-201 on reactor head.

When the shut-down causes have been removed, start again compressor, fresh LAB

and sulphur.

7.5) OTHER EMERGENCY SITUATION

If for some reason the plant must be brought immediately in safety conditions actuate

the following actions:

- Stop sulphur pump P-102.

- Open completely compressor vent line (PCV-101).

- Close UV-201.

- Put P-201 recycling from T-204 and reactor head.

- Stop compressor CO-101.

As soon as the causes of the emergency situation have been removed, start again the

compressor, LAB and sulphur.

65

If the plant can not restart, proceed for plant shut-down for short or long time.

8) INTERLOCK SYSTEM

The plant is provided with a safety system which protects personnel, machinery and

production from damages consequent to anomalous plant conditions and operator

mistakes.

The interlock can be excluded only in phase of start-up under responsibility of the plant

manager, who must again include it as soon as this phase has been overcome.

During the start-up phase, when the interlock is excluded, the plant manager must

personally check that the operation is executed by the operator in the correct way.

In the following schedule the causes/effects of the interlock have been collected.

SITUATION OF AUTOMATIC VALVES IF AIR OR ELECTRIC POWER ARE MISSING

Air off Power off

PCV - 101 opens opens

TCV - 101 opens opens

LCV - 161 closes closes

KV - 101 remains in the same position remains in the same position

KV - 102 remains in the same position remains in the same position

KV - 103 remains in the same position remains in the same position

KV - 104 remains in the same position remains in the same position

KV - 105 remains in the same position remains in the same position

KV - 106 remains in the same position remains in the same position

KV - 107 closes closes

KV - 108 closes closes

KV - 109 closes closes

KV - 110 closes closes

UV - 201 closes closes

UV - 202 opens opens

KV - 111 closes closes

66

P-1

05

P-1

06

AG

-101

AG

-102

F-3

01

P-3

02

P-1

01 A

/B

CO

-101

E-1

06

MY

-val

ve

UV

-202

UV

-201

PC

V-1

01

P-1

02A

/B

P-2

01A

/B

LAH-141 S

TAL-141 Ds Ds Ds Ds

BL-301 off Ds

LSL-301 Ds

LSL-121 Ds

PCV-101 close Ds

UV-201 close Ds

TAH-101 S

PAH-101 S

FSL-161 S

TSH-163 S

CO-101 off Ds

CO-101 on O

CO-101 off

C

P-201°/B off O

FICAL-201 O

POWER off O

LSLL-161 C O S

TSH-161 C O S

P-204 off C O S

BL-102 off S

FIRAL-161 S

PSH-160 S

LSL-201 Dc

UV-201 closes S

C = closesD.C. = doesn’t closeO = opensS = stopsD.S. = Doesn’t start

67

9) MATERIAL BALANCE

The material balance has been performed for:

- LAB molecular weight 242.

- 3000 Kg/h production LABS.

- 4,5 % SO3 concentration in the reaction gases.

- Gas temperature in the sulphur furnace exit 750°C.

- Quench air to the converter beds as per instruction received by the catalyst supplier

(Monsanto).

68

IMPUT DATA

parameters Unite values Notes

Sulphonic Acid Production at 100% kg/h 3.000,000  

percentage of sulphonic acid coming from reactor

% 0,985 98,5% from calculation data

percentage of free oil coming from reactor % 0,010 1% from calculation data

percentage of sulphuric acid coming from reactor

% 0,005 0,5% from calculation data

Organic's molecular weight kg/mole 240,000 from calculation data

SO3 molecular weight kg/mole 80,000

sulphonic acid molecular weight kg/mole 320,000

SO2 molecular weight kg/mole 64,000

Sulphur molecular weight kg/mole 32,000

Air molecular weight kg/mole 29,000 stated for depleted air, too.

Oxygen molecular weight kg/mole 16,000

Caustic soda molecular weight kg/mole 40,000

percentage of SO3 that reacts % 0,997 stated 99,7%

percentage of SO2 that becomes SO3 % 0,985 stated 98,5%

sulphur percentage that becomes SO2 % 0,995 stated 99,5%

SO3 molecular percentage at reactor inlet % 0,045 4,5% from practical experience.

Molecular percentage of SO2 at burner outlet. % 0,075 7,5% from practical experience

weight rate of 1st quench air / SO3 total kg/kg 2,275 from converter calculations (approx.)

weight rate of 2nd quench air / SO3 total kg/kg 0,246 from converter calculations (approx.)

weight rate of 3rd quench air / SO3 total kg/kg 0,065 from converter calculations (approx.)

Air lost through RO-101 (25-PA-115-CS01-P) kg/h 50,000 valuation equal for all the capacities.

humidity quantity in dry air g/kg 25,000 for T=35°C and RH = 70%

Humidity absorption ratio adim 1,000 100% with good approximation

Flow rate increment due to overflow % 7,500 to have a good regulation

caustic soda concentration (base water) % 30,000  

soda percentage that becomes sulphate-sulphite

% 0,775 77,5% ; the remaining becomes water

NOTES:      

the balance has some exemplifications, that means that the following elements are not considered:

1 - oleum blow down before reactor      

2 - H2SO4 formation process      

3 - presence of inerts in sulphur      

4 - some other details        

BALANCE OF REACTOR + SEPARATOR69

Take some product at reactor outlet

Solphonic Acid kg/h 3.000,000  

Free oil kg/h 30,457  

Solphoric Acid kg/h 15,228  

Total kg/h 3.045,685  

Organic capacity to send to the reactor

Moles of produced solphonic acid moles/h 9,375  

Moles of organic that do not react (free oil) moles/h 0,127  

Total moles of organic to be sent to the reactor moles/h 9,502  

Total organic kg/h 2.280,457  

Gaseous stream capacity to send to the reactor

SO3 reacting moles moles/h 9,375  

SO3 not reacting moles moles/h 0,028  

SO3 moles to send to the reactor moles/h 9,403  

total moles of gaseous stream to send to the reactor

moles/h 208,960  

Air moles + SO2 to reactor moles/h 199,557  

SO2 moles to reactor moles/h 0,143  

Moles of depleted air to reactor moles/h 199,414  

depleted air capacity to reactor kg/h 5.783,000  

depleted air capacity coming form converter kg/h 5.710,980  

capacity of normal air for dilution to reactor kg/h 72,021  

Summering of gaseous inputs      

  depleted air kg/h 5.783,000  

SO3 kg/h 752,257  

  SO2 kg/h 9,165  

material for H2SO4 kg/h 10,152

total gaseous input kg/h 6.554,574  

 

gaseous stream capacity at separator outlet

SO3 that did not react kg/h 2,257  

SO2 in/out kg/h 9,165  

depleted air in/out kg/h 5.783,000  

total gaseous output kg/h 5.794,422  

Group balance

Inlets in liquid phase kg/h 2.280,457  

70

  in gaseous phase kg/h 6.554,574  

total inlets kg/h 8.835,031  

Outlets in liquid phase kg/h 3.045,685  

  in gaseous phase kg/h 5.794,422  

Total outlets kg/h 8.840,107  

Difference between inlet and outlet kg/h -5,076 Should be 0, but can be accepted

CONVERTER BALANCE

Moles of SO2 from burner to converter. moles/h 9,546  

moles of SO2 that becomes SO3 moles/h 9,403  

moles of O2 kept from air for conversion moles/h 9,403  

O2 kept form air for conversion kg/h 150,451  

moles of SO2 that do not become SO3 moles/h 0,143  

obtained capacity of SO3 kg/h 752,257  

total moles of air stream from burner to converter moles/h 127,285  

moles of depleted air from burner to converter moles/h 117,739  

depleted air capacity from burner to converter kg/h 3.414,431  

depleted air capacity at converter outlet kg/h 3.263,980  

air capacity for 1st quench kg/h 1.745,000  

air capacity for 2nd quench kg/h 399,000  

air capacity for 23rd quench kg/h 303,000  

inlet depleted air kg/h 3.414,431  

  SO2 kg/h 610,970  

  sulphur innerts kg/h 1,535  

normal air at quenches kg/h 2.447,000  

total inlet kg/h 6.473,936  

outlet depleted air kg/h 5.710,980  

SO3 kg/h 752,257  

  SO2   9,165  

sulphur innerts kg/h 1,535  

total outlet kg/h 6.473,936  

difference between inlet and outlet kg/h 0,000

BURNER BALANCE

depleted air capacity at burner outlet kg/h 3.414,431  

moles of depleted air at burner outlet moles/h 117,739  

71

sulphur moles that become SO2 moles/h 9,546  

sulphur moles that do not become SO2 moles/h 0,048  

Total sulphur moles to be fed to the burner moles/h 9,594  

Oxygen moles to make SO2 moles/h 19,093  

total moles at burner outlet moles/h 127,285 depleted air summ + SO2

Moles concentration of SO2 at burner outlet % 7,500

sulphur capacity that becomes SO2 kg/h 305,485  

sulphur capacity that does not become SO2 kg/h 1,535  

oxygen capacity to make SO2 kg/h 305,485  

inlet normal air kg/h 3.719,916  

sulphur kg/h 307,020  

total inlet kg/h 4.026,936  

outlet depleted air kg/h 3.414,431  

SO2 kg/h 610,970  

sulphur innerts kg/h 1,535  

total outlet kg/h 4.026,936  

difference between inlet and outlet kg/h 0,000

AIR DRYERS BALANCE

Air percentage for the burner kg/h 3.719,916  

Air percentage for converter quenches kg/h 2.447,000  

Air percentage for dilution for reactor kg/h 72,021  

total dry air at airdryer outlet kg/h 6.238,937  

dry air lost from equalization hole kg/h 50,000

total air to dry kg/h 6.288,937  

total water in the air at airdryer inlet kg/h 157,223  

kept water in airdryer kg/h 157,223  

inlet humid water kg/h 6.446,160  

total inlet kg/h 6.446,160  

outlet dry air kg/h 6.288,937  

water kg/h 157,223  

total outlet kg/h 6.446,160  

difference between inlet and outlet kg/h 0,000

 

COMPRESSOR CALCULATION

overflow air quantity kg/h 483,462  

Total air to be sent to airdryers kg/h 6.446,160  

72

total compressor capacity kg/h 6.929,622  

 

ELECTROFILTER BALANCE

depleted air that in/out comes kg/h 5.783,000  

SO2 that in/out comes kg/h 9,165  

SO3 that incomes and becomes oleum kg/h 2,257  

Oleum at burner outlet kg/h 2,257  

total inlet kg/h 5.794,422  

total outlet kg/h 5.794,422  

difference between inlet and outlet kg/h 0,000

       

SCRUBBER BALANCE

depleted air at inlet kg/h 5.783,000  

SO2 at inlet kg/h 9,165  

Moles of SO2 at inlet moli/h 0,143  

needed moles of NaOH moli/h 0,286  

NaOH capacity (at 100%) kg/h 11,456  

Solution capacity of NaOH (at 30%) kg/h 38,186  

NaOH water solution capacity kg/h 26,730  

sulphate-sulphite capacity at outlet kg/h 18,043  

water capacity produced at outlet kg/h 2,578  

total inlet kg/h 5.830,351  

total outlet kg/h 5.830,351  

difference between inlet and outlet kg/h 0,000

10) GENERAL MAINTENANCE

73

For detailed maintenance of equipment see the technical documentation supplied by the

constructor.

For general maintenance rules relevant to the main plant equipment follow these

instructions:

- Once a year inspect the demister of F-102

- Once a year inspect from man-hole the driers T-102 A/B

- Once a year check aspect and freezing point of the glycol solution

- Once a year or when necessary clean the bottom of the melter H-101

- Once a year inspect T-105 and T-104

- Once a year inspect sulphur furnace BR-101 up and down and the process outlet of

E-107

- Converter R-101: the catalyst life is more than five years. However, the first bed

trends to pack and the pressure drop through the converter starts to increase. So

once a year could be necessary to remove the first bed, to sieve it and to put it back

to the relevant place.

- Once a year inspect the demister of F-104.

- Once a year or more inspect the distribution head of reactor R-201 without touching

the calibration nozzles.

- Once a year inspect the filter F-202.

- Once a year inspect the ESP F-301 up and down.

10.1) CLEANING OF REACTOR HEAD

74

If the Klett colour in the product is too high, the organic nozzles might be dirty of

carbonized material. In such a case proceed to clean the reactor head with water

following this procedure:

- Stop the plant as per “shut-down procedure for short time” but blowing air by the

compressor through the reactor and the plant for at least one hour.

- Stop the compressor and close UV-201.

- Disconnect the LAB feeding line to the reactor head.

- Disconnect the pipe from reactor bottom cone and R-202.

- Discharge the LAB from the organic chamber through the relevant hole (close by a

plug).

- Connect the organic chamber with a hose and feed water from the water net.

- Wash until the water is clean.

- Stop the cleaning operation and disconnect the water hose.

- Connect the organic chamber with instrument air by a hose and blow for 2-3 hours.

- Stop the drying operation and connect again the process pipes as before.

- Now the plant can be started following the relevant procedures.

11) ANNEXES 75

11.1) ALUMINA TANKS T-102 A/B

Instructions for activated alumina loading.

0) Open both man-holes of the tank T-102. At least two operators should be

assigned to this job.

One of them, small size, should be enter into the tank without shoes.

1) You have available, supplied by Marsina, 6720 kg ( 8400 lt.) of alumina type

A.A.2-5 grade D (sub-supplier Rhodiachem Italia), packed in 160 Kg ( 200 lt.)

drums (total drums 42 )

2) you have available n. 45 of ¾” ceramic balls packed in 25lt. bags (sub-supplier

Rauschert)

3) the volume inside T-102 foreseen for alumina + ceramic balls is about as follows:

diameter 1,8 x 1,8 x 3,14 / 4 = 2,54 m2 x 1,75 = m3 4,445

4) we have foreseen to set on the grid about 100 mm of ¾” ceramic balls layer to

avoid falling down of alumina through the grid openings and other 100 mm. of the

same balls on the upper alumina surface to avoid the alumina pellets dragging by

the air. That is about 250lt on the grid and 250 lt on the alumina surface.

5) the volume available for alumina is so 4445- 500 = 3945 lt. that is about 20

drums

6) finally for each T-102 proceed as follows :

- charge on the grid 250 lt. (10 bags) of ¾” ceramic balls and distribute

them equally as much as possible

- charge now on the balls 20 drums of alumina distributing it equally as

much as possible

- charge on the alumina 250 lt. (10 bags) of ¾” ceramic balls and distribute

them equally as much as possible

- close the man-holes

11.2) GENERAL NOTES ABOUT SULPHUR FILTRATION

76

Sulphur is present in the earth's crust as well as the ocean in its elemental state and as

sulphides and sulphates.

The most important sulphides are pyrite, chalcolite, sphalerite and galena.

The principle sulphates are gypsum and kieserite.

There are three major types of sulphur deposits:

- The gypsum type (95% of the world's sulphur), as found in the USA, Mexico and

Sicily

- The solfataras (volcanic vents, formed by oxidation of hydrogen sulphide gas), as

found in Japan and Chile.

- The fumarole deposits (sinter deposits formed by interaction of sulphur dioxide and

hydrogen sulphide), as found in Mammoth Hot Springs, Yellowstone park.

Sulphur found in the USA (Louisiana and Texas) is mined by the Frasch process, which

incorporates a multi-wall well, Hot water is pumped into the formation, melting the

sulphur which is subsequently "pumped" to the surface by compressed air.

11.2.1) Sulphur Filtration

Elemental sulphur, used to produce sulphuric acid, is burned to produce a mixture of

oxygen, nitrogen and sulphur dioxide and suspended solids and/or ash will ultimately

foul boiler tubing, etc. and therefore requires filtration.

Molten sulphur filtration poses special demands upon filtration equipment since filtration

takes place at elevated temperature and corrosion of the vessel and internals may

occur unless the Ph is continuously monitored.

The sulphur viscosity is not a linear function with respect to temperature changes so

that the operating temperature must be kept with in certain boundaries if relatively

Constant filter rates are expected. All vessels, tanks, pits or piping must also be steam

jacketed, in order to control above mentioned operating conditions.

Sulphur obtains its corrosive aspects from the contaminants and the introduction of

moisture and/or air and acid formation may form under those conditions. To reduce air

77

formation inside the filler part of the unfiltered sulphur may be recirculated back to the

unfiltered pit.

Basically, the filtration of sulphur is necessary in order to remove the ash content.

Precoating the filler will normally be done with medium D. E, precoat grades, Perlite or

combination of D. E. and fibrous precoat grades, the latter of value when leaves get old

and screening show minor wear and tear. Body feed is recommended, as blinding of the

filter cake otherwise will occur prematurely, Body feed grades are generally a little

tighter (D. E. b diatomaceous earth) than the precoat grades. Bleaching clay, in some

instances, may be used as body feed to assist in removal of carbonaceous, tarry solids

present.

In order to reduce the acid content of the sulphur, neutralization is accomplished by

adding hydrated lime, ammonium bicarbonate as neutralizing agents.

Depending upon the source of sulphur and its handling practices, in terms of filtration

requirements, sulphur filtration is based on the following average flows and cycles.

Sulphur filtration is a fixed leaf filter application. For small plants, vertical filters with full

top and bottom opening covers may be applied.

However, most flow rates will require a horizontal shell vertical fixed leaf design,

The cleaning step for sulphur filters needs further thought since the conventional HF

type (High frequency/low amplitude) vibrator does not get the cake off the leaves too

well. Most filter manufacturers have, in the past, been saddled with manual cleaning

recommendations such as the use of rubber or wooden mallets or non metallic cake

scrapers (to prevent screen damage), The reciprocating cylinder type vibrator has been

used with some degree of success and should be offered as part of the filter package.

Inspection of the leaves after cleaning however should be recommended.

The filter cake will release best, when left on the leaves after retraction for approx 15

minutes.

Filter cake is very combustible. Protect filter from wind to minimize Ignition of the cake

resulting in damage to the fine outer screening. Keep fire extinguisher near the filter

location.

Due to excessive strain placed upon the filter leaves in terms of operating temperature

(between 120 and 150° C), cleaning method and filter cake nature, it is important that

the filter leaves are of heavy duty design.

78

Even though residual amounts of precoat material (after leaf cleaning) will not impede

the flow during subsequent cycles, occasional soaking of the leaves in hot clean sulphur

(or a suitable cleaning compound) is recommended in order to prevent long range

blinding of the filter cloth.

More than anything else in Importance, the sulphur must be neutralized (to eliminate

acid corrosion upon the filter leaves) in the precoat pit and/or unfiltered sulphur pit.

Materials of constructions:

- Carbon steel shell and internals

- Filter leaves 316 ss with 24x110 mesh filter screens suitable for D.E. precoating.

Steam jackets for 5 to 6 bar working pressure.

Precoat and unfiltered sulphur pits provided with 5-6 bar steam coils.

Conventional precoat piping system (also jacketed).

Special submerged sulphur pumps.

Good piping design provides for jacketed piping to keep filter free of air (from top vessel

back to unfiltered sulphur pit) and jacketed piping to allow for filtered sulphur

recirculation back to the unfiltered sulphur pit during production interruptions &o that the

filter cake will not slough off the leaves.

11.2.2) Filtration Of Molten Sulphur

Basic filter design:

1. DRY CAKE DISCHARGE (preferred)

a. vertical tank with bottom opening head, minimum floor space, low first costs,

leaves not fully exposed for cleaning

b. horizontal tank with retractable carriage, easier to clean (leaves fully exposed)

more floor space, somewhat higher in costs in sqm of area than vertical tank.

2. SLURRIED CAKE DISCHARGE

79

Cake re-slurred in sulphur results in high sulphur load with cake or necessitates

recycle to melting pit which must than be cleaned more frequently (vertical! tank) filter

recommended with vibrator.

3. FILTER TANK

a. carbon steel (5 Bar)

b. steam jacket (5 Bar)

e. jacketed connections (flanged)

d. silicone or Viton gaskets.

4. LEAVES

a. 24x110 Mesh Plain Dutch Weave in SS 316

b. drainage screen and balance of leaf in carbon steel or SS 304

e. "O" ring gaskets in Viton

d. 4+5" leaf spacing.

5. ACCESSORIES

a. jacked carbon steel precoat tank (volume equal to 1,3 times the volume of the filter

tank).

b. jacketed interconnecting pipe, valves and fittings

c. jacketed submerged pumps for precoating and feed.

11.2.3) Operation

1. PRE TREATMENT OF SULPHUR IN PIT

a. Neutralize all free acid with hydrated lime (0,5 kg, lime per 0,5 kg free acid).

b. Boil off all moisture (12 ÷ 24 hrs holding time in melting pit).

c. Maintain 140 ÷ 150° C temperature (minimum viscosity).

2. PRECOAT

80

a. moderately coarse filler aid (Celite 503 or Dicaiite Speedex)

b. Hydrated time (0,3 ÷ 0,4 kg/sqm).

c. Mix filler aid and lime with previously filtered sulphur

d. Recirculate 10 +15 minutes.

3. FILTRATION

a. Maintain Constant filtration rate somewhat higher than burning rate to balance

filter down time and hold filtered sulphur level.

b. Variable speed pump drive recommended (steam turbine drive works out nicely).

11.2.4) Filter Sizing

1. BRIGHT SULPHUR

Area required 0,1 ÷ 0,3 sqm per ton S per day.

Cycles 1 ÷ 3 days between cleaning without filler aid admix.

2. DARK SULPHUR

a. With O,05 % filter aid admix.

Area required 0,15 ÷ 0,25 sqm per ton S per day.

Cycles 8 ÷ 24 hours between cleaning.

11.2.5) General comments

1. Filter leaves should occasionally be soaked in clean molten sulphur to prevent

gradual blinding of the wire screen.

2. Bolted leaf construction is recommended to allow field replacement of wire cloth if

necessary.

3. Filter should be sheltered from wind to minimize change of ignition of the cake when

the tank is opened. Sulphur flame can burn through 24x110 mesh wire cloth.

4. Filter cake and pit sulphur should be checked regularly for free acid which will

corrode the filters.

81

5. Use of combustible filter aids such as Solka Floc (cellulose and carbon) will minimize

ash in converter, should a broach occur in any of the leaves. These materials are

somewhat more expensive than diatomaceous earth, however proper filter operation

and leaf maintenance should eliminate their need.

For bright sulphur use Speedex or Celite 503. For dark sulphur use Hy-Flo.

Precoat quantity about 1 kg per 1 sqm of filter area. Lime is added to the unfiltered pit,

Generally additional lime is added past the neutralization mark to get rid of any free

acid.

11.3) CONVERTER CATALYST LOADING INSTRUCTIONS

After the installation of the four grids and the three air plate distribution, you can

proceed to the catalyst loading following the procedures here specified, operating from

the man-holes.

For the equalization of the layers, use a small rake or similar.

Take care of the thermocouples installed inside the converter.

1) Open all the four man-holes

2) Wad the gap between the grid edge and the inner converter wall using the

relevant packing supplied by Marsina with the help of a device like a screwdriver or

similar. This operation plugs a possible by-pass of the catalyst by the SO2/air gases.

3) You have available supplied by Marsina n .30 of 1” ceramic balls bags, 25 lts.

each bag. Sub-supplier “Rauschert”. These balls should be set on each grid before

the catalyst to avoid the catalyst pellets fall down through the grids openings and

after the catalyst to avoid dispersion of the pellets their self. In both cases the

thickness should be about 50 mm. that is about a two balls layer. Being the inner

converter diameter 1450 mm., each bed needs 1,45x1,45x3,14/4 =m2 1,65

82

1,65x0,05 = 0,0825 mcx2 = 0,165 mc = 165 lt.of 1” balls = 6,6 bags ; 3,3 bags on

the grid and 3,3 bags on the upper catalyst surface.

4) Proceed for each bed starting from the bottom (fourth bed), setting the lower

ceramic balls layer, the catalyst and then the upper ceramic balls layer.

5) During the catalyst handling the operators should wear anti-dust mask.

6) the Monsanto catalyst supplied by Marsina is of two types :

a. type XLP-120 to be installed in the first bed (top bed) lt. 800

b. type XLP-110 to be installed in the second bed lt. 900

c. type XLP-110 to be installed in the third bed lt.1000

d. type XLP-110 to be installed in the fourth bed(bottom)lt.1000

it has been supplied in 200 lts.drums , 4 drums XLP-220 and 15 drums XLP-

110.

So you should distribute it in this way:

- 4,0 drums XLP-120 in the first bed (top)

- 4,5 drums XLP-110 in the second bed

- 5,0 drums XLP-110 in the third bed

- 5,0 drums XLP-110 in the fourth bed (bottom)

7) After the operation has been completed, close the man-holes putting the

insulation inside the cover as per previous instructions already in your hands.

11.4) R-301 SCRUBBER

83

Information about possible ways for scrubber management.

The R-301 scrubber can be managed in two different ways:

1) At pH close to neutrality 7,2-7,5

In such a case the scrubber works continuously. A small amount of caustic is

continuously fed to scrubber by means of the dosing pump P-302 under control of

the pH-meter.

The SO2 absorbed gives Na2SO3 which is oxidized to Na2SO4 (roughly 80% sulphite

and 20 % sulphate).

The sulphite/sulphate solution is continuously transferred to the storage, being the

level in R-301 maintained by water make-up.

The management of the scrubber in this case requires more care and control, but

gives much more advantages from production and pollution point of view.

2) In excess of caustic soda at pH close to 14

In such a case the scrubber works batch wise. That is initially an amount of caustic

necessary to neutralize the SO2 for 24-36, it hours is fed to the scrubber with some

excess.

The pump P-302 is stopped, of course.

The scrubber will produce only sulphite.

The concentration of sulphite will start from zero and will gradually increase.

The level in R-301 will be maintained by water make-up.

When the concentration will reach the desired value (not more than 10-12 %), the

scrubber must be emptied and the caustic solution renewed.

The management of the scrubber in this case does not require much care, but the

production of sulphite can give pollution problems.

11.4.1) Procedures for R-301 management.

84

These procedures start with empty scrubber.

Volume of tank-scrubber about 7mc.

Useful volume about 6mc.

Plant capacity 3000 Kg/h

Solids concentration required in R-301 10%

Solution density 1,1

30% caustic soda density 1.33

Case n. 1

- Fill the scrubber with about 5000 lt. of water.

- Put the pH-meter in automatic mode and set the pH value at 9.

- Start the pump P-302.

- Start the recycling pump P-301 and fix the recycling rate at about 25 mc/h.

- Keep close the transfer line to the storage.

- When the pH will reach value 9 bring the level with water to the floating regulator.

- Bring back the set of the pH-meter to 7,5. The pump P-302 will stop immediately.

- Now the scrubber is ready to receive the exhausted gas. The sulphite/sulphate

concentration will increase gradually and in about 37 hours will reach 10%

concentration.

- When 10% concentration has been reached (check the density), the transfer to the

storage can be started.

- From material balance we get:

Na2SO3/Na2SO4 production about 18 Kg/h = 180 Kg/h al 10% = 164 lt/h

NaOH required 11,5 Kg/h at 100% = 38,2 Kg/h al 30% = lt/h 28,7

- So we have to transfer to the storage 164 Lt./h to maintain the concentration around

10%.

- Increasing the amount of the transfer decreases the concentration and viceversa.

Case n. 2

- Fill the scrubber with about 4000 lt. of water.

85

- Put the pH-meter in manual mode.

- Add 1413 Kg of NaOH at 30%.

- Start the recycling pump P-301 and fix the recycling rate at about 25 mc/h.

- Keep close the transfer line to the storage.

-The ph will be 14. Bring the level with water to the floating regulator.

- Now the scrubber is ready to receive the exhausted gas .The sulphite/sulphate

concentration will increase gradually and in about 37 hours will reach 10%

concentration.

- When 10% concentration has been reached (check the density) ,transfer as much as

possible the content of the R- 301 to the storage always maintaining the recycle.

- Add again 1413 Kg of NaOH 30%

- Add water up to floating regulation.

- After about 37 hours repeat the operation and so on.

Useful calculation

SO2 8,9 Kg/h

NaOH 11,5 Kg/h = 38,2 Kg/h al 30%

H2O with soda 30% = 26,7 Kg/h

Reaction water 2,4 K/h

Solids as sulphite 8,9+11,5 –2,4 = 18 Kg/h

For 10% conc. we have to add H2O = 180-18-2,4 = 159,6 Kg/h of which 26,7 come from

soda 30%, while the fresh one is 159,6-26,7= 129,9 Kg/h

Total : 8,9+11,5+159,6 = 180 Kg/h /1,1 = 163,6 Lt./h

18/180 = 10%

The water which goes out with the gas at 50 °C is about 350 Kg/h (7000 Kg/h x

50gr/Kg)

At about 6000 lt. R-301 should be almost full, that is after 6000/163,6 = 37 hours

compensating the water which evaporate with the exhausted gas.

In 37 hours the inputs should be :

86

8,9x 37 = 330 Kg SO2

38,2x37 = 1413 Kg NaOH 30%

129,9x 37 = 4806 Kg H2O

Total 6549 Kg/ 1,1 = lt.5954

The correspondent outputs should be:

18x37 = 666 Kg

666/6549 = 10 %

87