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Aromatics Uhde ThyssenKrupp A company of ThyssenKrupp Technologies

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Page 1: Aromatics - thyssenkrupp Industrial Solutions Mé · PDF fileThe main sources of aromatics (benzene, tolu-ene, xylenes) are reformate from catalytic re- ... • Light reformate from

Aromatics

Uhde

Thys

senK

rupp

A companyof ThyssenKrupp

Technologies

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Table of contents2

1. Company profile 3

2. Uhde and Aromatics 5

3. Aromatics – Sources, Demand and Applications 6

4. Process Configuration 84. 1 Aromatics from Pyrolysis Gasoline 84. 2 Aromatics from Reformate 124. 3 Aromatics from Coke Oven Light Oil 15

5. Technology 165. 1 Hydrogenation Technology 165. 1.1 Hydrogenation of Pyrolysis Gasoline 165. 1.2 Hydrogenation of Reformate 185. 1.3 Hydrogenation of Coke Oven Light Oil 195. 2 Fractionation Technology 205. 2.1 Conventional Distillation 205. 2.2 Divided Wall Column Distillation 205. 3 Morphylane® Extractive Distillation 225. 3.1 Conventional Morphylane® Process 225.3. 2 Nitrogen Guard Bed 235. 3.3 Single-Column Morphylane® Extractive Distillation 235. 4 Hydrodealkylation Technology 255. 5 Toluene Disproportionation Technology 255. 6 Toluene/C9+ Transalkylation Technology 265. 7 Para-Xylene Adsorption Technology 265. 8 Xylenes Isomerisation Technology 27

6. Operating Results of Extractive Distillation Plants 28

7. Laboratory, Analytical and R&D Services 307. 1 Analytical Facilities 307. 1.1 Gas chromatography 307. 1.2 Physical and chemical methods 307. 1.3 Other analytical methods 307. 2 Determination of thermohysical properties 307. 3 Pilot Plant Tests 317. 3.1 Separation techniques 317. 3.2 Absorption/adsorption techniques 31

8. Services for our customers 32

9. Main references 34

Page

Aromatics complex for BASF, Mannheim/Germany.

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1. Company profile 3

Uhde’s head office in Dortmund, Germany

With its highly specialised workforce of more than 4,900 employees and its international network of subsidiaries and branch offices, Uhde, a Dortmund-basedengineering contractor, has, to date, successfully completed over 2,000 projectsthroughout the world.

Uhde’s international reputation has been built on the successful application of its motto Engineering with ideas to yield cost-effective high-tech solutions for itscustomers. The ever-increasing demands placed upon process and application technology in the fields of chemical processing, energy and environmental protectionare met through a combination of specialist know-how, comprehensive service packages, topquality engineering and impeccable punctuality.

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2. Uhde and AromaticsRemarkably long experience

Uhde’s extensive knowledge in extractive distil-lation technology and its excellent laboratoryfacilities have led it to develop the most advancedprocess configurations for recovering aromaticsand other products, such as butenes, a-olefins,cumene, isoprene and phenols, from differentfeedstocks.

Uhde’s history in aromatics goes back to thefirst decades of the 20th century when HeinrichKoppers developed the Koppers coke oven tech-nology for the production of coke for the steelindustry. Right up to the fifties, coke oven lightoil, which is recovered as a by-product of crudecoke oven gas in coke oven plants, was theworld’s main aromatics source.

Due to the large quantity of impurities (diolefins,olefins, nitrogen, oxygen and sulphur compounds)the coke oven light oil had to be purified beforethe aromatics could be recovered. In thosedays, the lower benzene quality requirementscould be met by sulphuric acid treatment andconventional distillation processes. However, thelarge quantity of aromatics lost during sulphon-ation and the relatively high sulphur content inthe benzene product were the driving force inthe development of a hydrogenation processwhich was worked on together with BASF AG,Ludwigshafen, Germany and which solved theproblems caused by unsaturated and inorganicimpurities in the feedstock. The final purificationof aromatics continued to be achieved by distil-lation only.

At the beginning of the fifties, high-purity aro-matics recovered by liquid-liquid extraction inrefineries came on to the market. The superiorquality of these aromatics made it impossible forthe aromatics distilled from coke oven light oil tocompete. In addition, the improved purificationprocess using azeotropic distillation was linkedwith high investment costs and inefficient energyutilisation.

The liquid-liquid extraction process could not be used for coke oven light oil with an aromaticscontent of 95% as separable phases are notable to form when the aromatics content is thishigh. At the request of the German coal andsteel industry, Uhde initiated intensive R&D activities and developed a new process for cokeoven light oil to obtain aromatics of a similar or better quality than those from refineries.

The process developed by Uhde was based on a new solvent called N-formylmorpholine andused a different separation principle involvingextractive distillation. The process was able toproduce all the product purities required whilstreducing utilities consumption considerably ascompared to liquid-liquid extraction processes.

The first commercial plant based on this extract-ive distillation process (Morphylane® process)went on-stream in 1968 and produced excellentresults with regard to product quality and utilityconsumption figures.

Based on the outstanding performance of thisplant, the Morphylane® process was subse-quently adapted to other feedstocks, such aspyrolysis gasoline and reformate. The processhas undergone continuous improvements andoptimisation and its cost-effectiveness has led itto replace liquid-liquid extraction in all applica-tions. Furthermore, by optimising the combinationof all the processes involved, such as hydrogen-ation, fractionation and aromatics extractivedistillation, the complete process line for re-covering aromatics from all possible feedstockswas able to be improved to such an extent thatcompetitive processes were left standing.

Up to now, Uhde has been awarded contractsfor more than 60 Morphylane® plants worldwidefor recovering aromatics from pyrolysis gasoline,reformate and coke oven light oil. Leading aromatics producers, such as Chevron Phillips, Dow, BASF, Total, Shell and SK Corp., selectedthe Morphylane® process on the strength of itsoutstanding performance figures and its optimisedprocess configuration after comparing it withcompetitive technologies.

Uhde provides its customers with the followingservices in the field of aromatics production:

• Consulting services• Analytical services• Licensing• Engineering• Procurement• Construction• Plant operation• Maintenance services• Plant optimisation services

5

Erection of the 60 meter high benzeneextractive distillation column for TitanPetrochemicals, Pasir Gudang, Malaysia.Capacity: 168,000 mtpy benzene andtoluene from pyrolysis gasoline.

Benzene

Toluene

Para-Xylene

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3. Aromatics – Sources, Demand and Applications6

Aromatics (benzene, toluene

and xylenes) rank amongst the

most important intermediate

products in the chemical

industry and have a wide range

of applications.

SourcesThe main sources of aromatics (benzene, tolu-ene, xylenes) are reformate from catalytic re-forming, pyrolysis gasoline from steam-crackersand coke oven light oil from coke oven plants(Fig. 3-01). The reformate from catalytic refor-ming provides the basic supply of benzene,toluene, xylenes and heavier aromatics. Themajority of toluene and heavier aromatics fromreformate is converted to benzene and xylenesand is mainly used for p-xylene production. Theremaining supply of aromatics is produced frompyrolysis gasoline and from coke oven light oil.

Benzene, which has the highest production ratebeside xylenes and toluene, is mainly producedfrom pyrolysis gasoline, followed by reformate.A significant percentage of Benzene, i.e.15%, isalso obtained from the hydrodealkylation (HDA)of heavier aromatics and from toluene dispro-portionation (TDP). The smallest percentage ofabout 5% of benzene is obtained from cokeoven light oil (Fig. 3-02).

Pyrolysis Gasoline 47%

Reformate 33%

HDA/TDP 15%

Coke Oven Light Oil 5%

World Benzene Sources

Reformate 68%

Pyrolysis Gasoline 29%

Coke Oven Light Oil 3%

World Aromatics Sources

Fig. 3-01 Source: HPP Science

Fig. 3-02 Source: HPP ScienceHDA: Hydrodealkylation of heavier aromatics TDP: Toluene disproportionation

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DemandWorldwide, approx. 110 million tonnes of BTXaromatics are currently produced per year. Anincrease in demand of almost 4% p.a. is pre-dicted for benzene due to the growth of end-usemarkets such as polystyrene, polycarbonate,phenolic resins and nylon (Fig. 3-03).

In the case of xylenes the increase in demand isdetermined by p-xylene, the biggest isomer interms of quantity. Growth in consumption of thisisomer is expected to well exceed 5% p.a. in thenear future. Para-xylene is used almost exclusivelyfor the production of polyester via purifiedterephthalic acid.

2005

0

10

20

30

40

50

20072009

Benzene

Toluene

Xylenes

(Million metric tons/year)

World Aromatics Demand

Ethylbenzene

Cumene

Cyclohexane

Nitrobenzene

Alkylbenzene

Chlorobenzenes

Nitrotoluenes

Solvents

o-Xylene

m-Xylene

p-Xylene

Styrene

Phenol

α-Methylstyrene

Caprolactam

Adipic Acid

Cyclohexanone

Aniline

LAB

Toluene Diisocyanate

Explosives, Dyes

Phthalic Anhydride

Isophthalic Acid

Terephthalic Acid/

Dimethylterephthalate

Polystyrene, ABS Resins, SBR

Aniline, Phenolic Resins, Epoxy

Resins, Surfactants

Adhesives, ABS Resins, Waxes

Polyamide 6

Polyamide 66

Polyurethane Foams

Alkyd Resins, Methylacrylate

Polyesters, Alkyd Resins

Polyesters

Benzene

Toluene

Xylenes

Fig. 3-03Source: HPP Science

Fig. 3-04Main Applications of BTX Aromatics

The estimated growth in overall toluene con-sumption is less than 3% p.a. Its major directchemical use is toluene diisocyanate (TDI), araw material for the production of polyurethane.Toluene extraction will increase as toluene isconverted into benzene and xylenes via disproportionation.

ApplicationsThe wide range of applications involving themain aromatics, benzene, toluene and xylenes(Fig. 3-04), illustrates the importance of theseintermediate products to the chemical industry.

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4. Process Configuration Aromatics from Pyrolysis Gasoline,Reformate & Coke Oven Light Oil

8

Off-Gasto Steamcracker

SelectiveHydrogenation

H2

C5- Fractionto Gasoline Pool

FullHydrogenation

H2

Dep

enta

nize

r

Sta

biliz

er

Benzene

Toluene

Non-Aromaticsto Steamcracker

C8+ Fractionto Gasoline Pool

ExtractiveDistillation

B/T

Col

umn

Deh

epta

nize

r

Crude PyrolysisGasoline fromSteamcracker

Aromatics (benzene, toluene, xylenes) are mainly recovered from the following three feedstocks:• Pyrolysis gasoline from steamcrackers• Reformate from catalytic reformers• Light reformate from aromatics production• Coke oven light oil from coke oven plants

The type of aromatics recovered and the processconfiguration are dictated by the feedstock used,as the composition of these feedstocks differswith regard to the content of paraffins, olefins,naphthenes and aromatics (Fig. 4-01) and theamount of impurities, such as chlorine, oxygen,nitrogen and sulphur components.

4.1 Aromatics from Pyrolysis Gasoline

Pyrolysis gasoline is mainly used to recover benzene as well as benzene and toluene to-gether. Producing mixed xylenes from pyrolysisgasoline is uneconomical due to the low xylenecontent and the high ethylbenzene content inthe pyrolysis gasoline.

A typical process route for recovering benzeneand toluene, starting from crude pyrolysis gas-oline, is illustrated in Fig. 4-02. In the first step,the selective hydrogenation, diolefins are satur-ated at a relatively low temperature to avoid

Fig. 4-02Aromatics from Pyrolysis Gasoline

Fig. 4-01 Typical Composition [wt.%]

Component

Benzene

Toluene

Xylenes

Ethylbenzene

C9+ Aromatics

Total Aromatics

Naphthenes

Olefins

Paraffins

Sulphur

Pyrolysis Gasoline

30

20

4

3

3

60

High

High

Low

Up to 1000 ppm wt.

Reformate

3

13

18

5

16

55

Low

High

High

< 1ppm wt.

Light Reformate

24

46

< 0.5

< 0.5

0

70

Low

Low

High

Low

Coke Oven Light Oil

65

18

6

2

7

98

High

High

Low

Up to 1 wt.%

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Off-Gasto Steamcracker

SelectiveHydrogenation

H2

BenzeneNon-Aromatics

to SteamcrackerC5- Fraction

to Gasoline Pool

FullHydrogenation

ExtractiveDistillation

H2

Dep

enta

nize

r

C9+ Fractionto Gasoline

Pool

Heavy AromaticsH2

Hydro-dealkylation

Off-Gas

Aromatics

B/T

Col

umn

Sta

biliz

er

Deh

epta

nize

r

Deo

ctan

izer

Crude PyrolysisGasoline fromSteamcracker

polymerisation. The C5- fraction is usually separ-ated from the selectively hydrogenated pyrolysisgasoline in a depentaniser upstream of the fullhydrogenation stage and sent to the gasoline poolas an octane-blending component. Thereby,hydrogen consumption is minimised and the sizeof the full hydrogenation unit can be reduced.

If, however, the C5- fraction is sent back to thesteamcracker as feedstock, it should be fullyhydrogenated and separated with the non-aromatics downstream of the full hydrogenationunit in a combined depentaniser/stabiliser or anextractive distillation stage. This dispenses withthe need for a complete depentaniser system.

Olefins as well as impurities, such as nitrogen,sulphur and other components, are completelyhydrogenated in the full hydrogenation unit. The off-gas containing H2S is separated in thestabiliser and then returned to the steamcracker.

In order to extract the required aromatics, a specific aromatics cut has to be separated fromthe pretreated pyrolysis gasoline. In the case ofbenzene recovery, a C6- cut is separated, in caseof benzene and toluene recovery, a C7- cut isseparated in a predistillation column and sent tothe extractive distillation. The C7+ or C8+ fractionis sent to the gasoline pool as feedstock.

Benzene or benzene and toluene are separatedfrom the non-aromatics in the extractive distilla-tion unit which comprises a simple two columnsystem. The non-aromatics are sent back to thesteamcracker as feedstock. In the case of combined benzene and toluene recovery, bothproducts have to be separated downstream in abenzene/toluene column system.

In some cases it can be more economical toconvert the C7+ aromatics into benzene to maxi-mise the benzene output. In this case, a thermalhydrodealkylation unit is integrated in such away that the extracted toluene and xylenes fromthe predistillation stage are dealkylated to formbenzene (Fig. 4-03).

Fig. 4-03Maximum Benzene Recovery from Pyrolysis Gasoline

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Aromatics complex for BASF in Mannheim/Germany. Capacities: 405,000 mtpy aromatics extraction,

340,000 mtpy hydrodealkylation

The full range:Consisting of pyrolysis gasoline full hydrogenation, pyrolysis gasoline separation, reformate separation, benzeneextractive distillation, toluene/xylene extractive distillationand hydrodealkylation.

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The off-gas produced can then be used as fuelgas. The toluene does not necessarily have tobe extracted before being fed to the hydrode-alkylation stage. However, if the toluene fractionis fed directly from the predistillation stage, more hydrogen has to be consumed to crack theC7 non-aromatics and consequently more off-gasis produced.

Depending on the feedstock available and theproducts required, individual process configur-ations and heat integration of the individual unitscan be optimised whilst taking into account localconditions such as specific utility availability andcosts. Uhde finds the most cost-effective solu-tions with regard to investment and operatingcosts for its customers.

4.2 Aromatics from Reformate

As a result of its relatively low benzene contentand relatively high toluene and xylenes content,reformate is mainly used to produce p-xylene.Another application for aromatics recovery is the reduction of benzene in motor gasoline byextracting benzene from the catalytic reformate.

P-Xylene ProductionThe typical process route for the production ofp-xylene from reformate is illustrated in Fig. 4-04.

In this case catalytic reformate is split into a C7- fraction and a C8+ fraction. The C7- fractionis then sent to the extractive distillation stage,where benzene and toluene are separated fromthe C7- non-aromatics.

H2 Light Ends

H2

XylenesIsomerisation

Benzene

Non-Aromaticsto Gasoline Pool

p-XyleneAdsorption

ExtractiveDistillation

Ref

orm

ate

Spl

itter

C9+ Aromaticsto Gasoline Pool

Toluene Dis-proportionation

p-Xylene

Xyle

ne C

olum

n

Ben

zene

Col

umn

Tolu

ene

Col

umn

Reformate fromCatalytic Reformer

o-Xylene

Light Ends

o-Xy

lene

Col

umn

C8+

C7–

Fig. 4-04Aromatics from Reformate

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The C8+ fraction is sent directly to the p-xyleneloop without the xylenes being extracted. Thenon-aromatics content in this fraction is very low and can therefore be easily handled in the p-xylene loop. Consequently only benzene andtoluene have to be extracted and not full-rangeBTX.

The toluene is fed to the toluene disproportion-ation stage where it is converted into benzeneand xylenes.

The benzene produced is separated as a high-purity product together with the extracted benzene, whilst the unconverted toluene is recycled back to the disproportionation.

After separation, the mixed xylenes fraction fromthe disproportionation, the xylenes fraction fromthe reformate splitter and the recycled xylenesfrom the isomerisation are sent to the p-xyleneadsorption, where p-xylene is separated fromthe xylenes. The remaining xylenes (m-xylene,o-xylene and ethylbenzene) are sent to the isomerisation to be converted into p-xylene.

If o-xylene is also to be obtained as a product, itmust be removed as a pure product by distillationin a separate column system before the xylenesenter the p-xylene isomerisation loop.

If maximum p-xylene production is required, a toluene and C9+ aromatics transalkylation isintegrated into the process configuration (notillustrated). With respect to an optimised heatintegration, vapours from the xylenes separationcan be used to heat the benzene and toluenecolumns and other consumers.

Half a million tonnes of benzene from reformate for Chevron Phillips Chemical Company,

Pascagoula, MS, USA

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Reformatefrom CatalyticReformer

SelectiveHydrogenation

H2 Off-Gas

Ref

orm

ate

Spl

itter

Non-Aromaticsto Gasoline Pool

ExtractiveDistillation

Benzene

C7+ Fractionto Gasoline Pool

14

Benzene Reduction in Motor GasolineIn order to comply with the latest regulationslimiting the benzene content in motor gasoline,the refining industry has to adjust its operationsto either convert or recover benzene and otheraromatics.

Uhde has developed an optimised Morphylane®

extractive destillation process for recoveringbenzene from reformate with lower investmentand operating costs (Fig. 4-05) compared toaromatics saturation, liquid-liquid extraction andother processes.

The reformate from the catalytic reformer is fed to the selective hydrogenation stage to saturate the diolefins which influence the acidwash colour (AWC) of the benzene product.

The selective hydrogenation unit consists of asmall reactor which is operated at low tempera-tures and pressure in a trickle phase. The smallamount of off-gas is separated in the reactorusing only phase separation. This upstream

hydrogenation of diolefins eliminates the necessityfor a downstream clay treating and subsequentproduct distillation thus saving considerably oninvestment and operating costs.

The pretreated reformate is fractionated and theC6- fraction is sent to the extractive distillationwhere high purity benzene is removed from thenon-aromatics in a simple two column system.One of the advantages of the Morphylane® ex-tractive distillation process is that both dissolvedhydrogen and light hydrocarbons can be easilyremoved with the overhead product therebysaving on investment for an upstream depent-aniser system.

Another advantage of the process is the excellent benzene purity. A very low benzenecontent in the non-aromatics (< 0.1 wt%) canbe achieved in the optimised extractive distil-lation configuration.

Determined by the specific requirements of therefiners, Uhde also provides other process configurations, e.g. a combination of reformatefractionation (producing several blending cuts)and benzene extractive distillation or a combinedbenzene and toluene extraction.

Fig. 4-05Benzene from Reformate(Benzene Removal from Motor Gasoline)

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Deh

epta

nize

rCoke OvenLight Oil

C8+

Hydrorefining

ExtractiveDistillation

C7-

C9+

Non-Aromatics

Tar

Toluene

Benzene

H2 Off-Gas

Xylenes

B/T

Col

umn

C8

Col

umn

Sta

biliz

er

C8-

15

4.3 Aromatics from Coke Oven Light Oil

Coke oven light oil is generally used as a feed-stock for recovering benzene, toluene, xylenesand higher aromatics as it has a very high aromatics content. The general process line forrecovering aromatics from coke oven light oil isillustrated in Fig. 4-06.

In a first step, the feedstock, which has a highcontent of impurities and a high content of olefins and diolefins, is hydrogenated. A specialhydrorefining process with a specific heating/evaporation system and a two stage reactionsystem is used for this purpose.

The hydrogenated coke oven light oil is sent tothe stabiliser where the off-gas, which containsfor instance H2S, is separated.

The stabilised coke oven light oil is then sent toa deheptaniser. The overhead C7- fraction is sentto the extractive distillation in which benzene andtoluene are separated from the relatively smallamount of non-aromatics in a single extractivedistillation before being split into high-puritybenzene and toluene.

The C8+ fraction leaving the bottom of the de-heptaniser is usually sent to another fraction-ation system where xylenes and higher aromaticsare recovered by distillation.

Uhde engineered the entire aromatics recovery complex for ARSOL Aromatics

in Gelsenkirchen/Germany, consisting ofhydrorefining, benzene extractive distillation and distillation of the benzene homologues

(Toluene, Xylenes and C9+ aromatics)from coke oven light oil.

Fig. 4-06Aromatics from Coke Oven Light Oil

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5. TechnologyHydrogenation Technology

16

5.1 Hydrogenation Technology

If pure aromatics are to beobtained, the feed must undergoa pretreatment before the non-aromatics and aromatics can beseparated by extractive distil-lation. Catalytic hydrogenationprocesses have become themost appropriate technologiesfor eliminating impurities suchas diolefins, olefins, sulphur,nitrogen and oxygen com-ponents.

5.1.1 Hydrogenation of Pyrolysis Gasoline

Due to its high diolefin content,crude pyrolysis gasoline fromsteamcrackers has a tendencyto polymerise and to form gumeven when stored in tanks undernitrogen blanketing. In view of

the fact that polymerisation is encouraged at higher tempera-tures, the diolefins have to behydrogenated at relatively lowtemperatures by highly activecatalysts in the so-called selective hydrogenation process.Once the diolefins have beensubjected to selective hydrogen-ation, other impurities can behydrogenated in the full hydro-genation stage at high tem-peratures.

Selective Hydrogenation (see Fig. 5-01)In this process step, crudepyrolysis gasoline is sent to thehydrogenation reactor afterhaving been mixed with hydro-gen. The reaction takes placein the trickle phase or in theliquid phase on nobel metalcatalysts (palladium on aluminium oxide carrier) or on nickel catalysts.

The selectively hydrogenatedpyrolysis gasoline leaves thereactor and is sent to a separ-ator where the remaininghydrogen is separated from the liquid phase. Depending on the catalyst selected, thegas phase is sent either to the fuel gas unit or to the fullhydrogenation stage in whichthe remaining hydrogen is utilised as a make-up agent.

After cooling, part of the liquid phase is recycled to thereactor to control the reactortemperature. The selectivelyhydrotreated product is fed toa fractionation column or issent directly to the full hydro-genation.

H2

SelectivelyHydrogenated

Pyrolysis Gasoline

Liquid Recycle

H2 Off-Gas

Separator

Reactor

Crude PyrolysisGasoline fromSteamcracker

Fig. 5-01Selective Hydrogenation of Pyrolysis Gasoline

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Full Hydrogenation (see Fig. 5-02)Impurities such as sulphur,nitrogen and oxygen compo-nents and olefins are hydrogen-ated in the full hydrogenationstage. The reactions take placein the gaseous phase on nickel/molybdenum and/orcobalt/molybdenum catalystsat reactor inlet temperatures ofbetween 240°C and 320°C.

To this end, the selectivelyhydrogenated pyrolysis gas-oline is fed to the reactor viafeed/effluent heat exchangersand a process heater afterhaving been mixed with recycled

hydrogen. After cooling, thereactor product is sent to a highpressure separator where thehydrogen, which has not beenconsumed, is separated fromthe liquid phase.

The remaining hydrogen is mixedwith fresh make-up hydrogenand fed back to the reactor.

The liquid reactor product, fullyhydrogenated pyrolysis gas-oline, is sent to a stabiliser system in which the off-gascontaining H2S is separatedfrom the product. The off-gasis normally recycled back tothe steam cracker, whilst the

stabilised reactor product is sent either to a fractionationcolumn or directly to the aro-matics recovery unit.

Various optimised processdesigns are provided dependingon the specific criteria, such asfeedstock specification, hydrogenquality, etc. In this respect someof the most cost-effective solu-tions with regard to investmentand operating costs includereactor-side intermediatequenching by cooled liquidproduct recycle, steam generation and additional reactive catalyst layers for difficult feedstocks.

Selectively HydrogenatedPyrolysis Gasoline

Recycle H2

Reactor Separator

Fully HydrogenatedPyrolysis Gasoline

High PressureSeparator

Make-up H2 Off-Gas

Fig. 5-02Full Hydrogenation of Pyrolysis Gasoline

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5.1.2 Hydrogenation of Reformate

Although high quality benzenecontaining less than 30 ppmnon-aromatics is produced byextractive distillation, even asmall quantity of diolefins(around 5 ppm) can result inan acid wash colour (AWC)specification higher than thatwhich is actually required. Ifdiolefins are present, especiallythose of a naphthenic naturethe reformate must be subjectedto an additional treatment stage.

As the most common unsatur-ated components, such as olefins and diolefins, are mostlyremoved by clay treating combined with a conventionalliquid-liquid extraction plant.One alternative is to install aselective hydrogenation stagefor the olefins and diolefinsupstream of the extractive distillation process. The catalystused for the selective hydrogen-ation of reformate has a longservice life and can usually beregenerated several times. Themaintenance savings are thusquite remarkable. In addition,disposing of clay has becomemore and more difficult due tothe enforcement of environ-mental protection laws in anincreasing number of countries.

The essential features of thecatalyst can be summarised asfollows:• high conversion rate with

regard to diolefins• reduction of olefins • low benzene losses (as

compared to clay treating)• long cycle length between

regeneration• long service life• mild operating conditions

The typical process scheme isillustrated in Fig. 5-03.

The benzene-rich cut upstreamof the extractive distillationstage is passed to the selectivehydrogenation reactor once therequired inlet temperature hasbeen reached. Hydrogen isadded to the benzene-rich cut.

Selective hydrogenation takesplace in the trickle bed of thereactor at low temperaturesand pressures. The product,which is free of diolefins, isthen passed directly to theextractive distillation stage.Separation of the gas phasetakes place in the reactor bottom. Additional stripping ofthe product is not necessary.

Reformate Fraction

H2

Reformate Fraction

Off-Gas

Reactor

Fig. 5-03Reformate Selective Hydrogenation

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19

5.1.3 Hydrogenation of Coke Oven Light Oil

In a similar way to crude pyro-lysis gasoline, coke oven lightoil also has to be hydrogenated.Impurities, such as organicsulphur, nitrogen and oxygencomponents, have to be re-moved and diolefins and olefinshave to be saturated to stabilisethe coke oven light oil and toassure high-quality final pro-ducts.

The “BASF-Scholven” processmeets all the above require-ments. The reactions take placein the gas phase on a nickel/molybdenum catalyst in theprereactor and on a cobalt/molybdenum catalyst in themain reactor.

Special emphasis is placed onthe evaporation of the cokeoven light oil feed. Uhde hasdeveloped a proprietary systemwhich permits smooth evapor-ation in a special multistageevaporator thereby minimisingfouling whilst achieving highon-stream factors without theaddition of fouling inhibitors.

The coke oven light oil is mixedwith make-up hydrogen andrecycle hydrogen and passedthrough a system of feed/effluent exchangers which arecombined with the stage evap-orator (Fig. 5-04). With theexception of a small quantity ofheavy hydrocarbons which arewithdrawn at the bottom of themulti-stage evaporator, almostall the feedstock is evaporated.

After being subjected to add-itional heating, this material isfed to the prereactor where mostof the diolefins are converted.The effluent from the prereactoris then heated further by a process heater. In the main reactor the olefins are saturatedand the remaining sulphur,nitrogen and oxygen com-pounds are hydrogenated. Aftercooling, the effluent from themain reactor is sent to the highpressure separator to disengagethe hydrogen from the liquidphase.

The separated hydrogen ismixed with make-up hydrogen,recompressed and returned tothe coke oven light oil feed.

The fully hydrogenated raffinatefrom the high pressure separatoris sent to a conventional stabiliser system. Off-gas containing H2S and NH3 isseparated from the raffinateproduct. The stabilised raffinateis sent to a fractionation andaromatics recovery unit.

Uhde offers a variety of processconfigurations adapted to thefeedstock conditions and customer requirements. Theheavy hydrocarbon residuecan, for example, be subjectedto further treatment in a tardistillation unit to enhance BTX aromatics recovery or toproduce valuable tar-derivedproducts.

Coke OvenLight Oil

RecycleCompressor

StageEvaporator

H2

TardistillationColumn

Tar

Pre-Reactor Main Reactor

HydrogenatedCoke Oven Light Oil

High PressureSeparator

Off-Gas

Fig. 5-04Hydrorefining of Coke Oven Light Oil

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Reformate orPyrolysis Gasoline

C8+ Fraction

C5 Fraction

C6/C7 Fraction

Fractionation Technology20

5.2 Fractionation Technology

For many decades, distillationhas been one of Uhde's keyareas. From hydrocarbon C2 andC3 distillation to C9 and C10 distil-lation, from crude distillation topure component distillation,Uhde can provide fractionationtechnology for virtually anyhydrocarbon system.

Our extensive experience isvery efficiently backed up byour laboratory and pilot plantfacilities. Hydrocarbon equilib-rium data can be measured inour laboratories and then implemented in conventionalstandard process simulators.

Fig. 5-05Divided Wall Column

Pilot testing may also be usedto confirm or demonstrate theseadapted models. Special feed-stocks can be tested in ourpilot plants allowing distillationprocesses to be optimised tomeet customer requirements.

5.2.1 Conventional Distillation

Uhde’s expertise includes distillation systems which useconventional tray technologyas well as random and struc-tured packing technologies.We have designed columns upto 10 metres in diameter andas high as 100 metres.

5.2.2 Divided Wall Column Distillation

Whenever more than two fractions have to be separatedby distillation, the question arises as to which is the mostefficient configuration (Fig. 5-05).

Configurations involving columnswhich are fully thermodynam-ically coupled have certainenergetic advantages over conventional fractionation tech-nologies. Latest technologicaldevelopments have, however,laid the foundation for adequatecalculation techniques andestablished the generic guide-lines for thermodynamic simu-lations. This has resulted inthe development of engineer-ing tools which permit theapplication of the divided walltechnology and which makeuse of the thermodynamicadvantages.

These advantages are reflected in:• up to 20% less investment

costs• up to 35% less energy costs• up to 40% less plant space

requirements

Uhde successfully introducedthis technology to aromaticsapplications. Two commercial-scale divided wall columns haverecently been commissioned foraromatics recovery. In addition,Uhde has installed divided wallcolumn test facilities in its ownlatoratories to work on furtherimprovements.

The divided wall column tech-nology is an excellent tool forrevamping plants, enhancingtheir capacity and improvingproduct qualities and yields.Existing hardware can be modified within one weekresulting in a short shut-downtime and low production losses.

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21

Plant converted to the dividedwall technology in just five days.

The Uhde team at the Ruhr Oel GmbH refinery in Münchs-münster in Bavaria had justfive days to convert a distil-lation column to a divided wallcolumn using one of Uhde’snew developments. The Uhdeteam managed to completethe task in the allotted timedespite inclement weather.

The divided wall column savedRuhr Oel having to build asecond column for removal ofbenzene so that the more stringent benzene specificationsin gasoline could be met. (left: old section of the existingcolumn, right: new divided wallsection before installation ofpackings).

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Morphylane® Extractive Distillation22

Main Features of the Morphylane®

Extractive Distilla

tion Process

Process features:

Simple plant arrangement

Low number of equipment (2 columns)

Little space required

No raffinate wash system required

Low solvent filling

Low investment

Low energy consumption

Easy to operate

No chemical agents required

High on-stream time

N-formylmorpholine solvent features:

High selectivity

High solvent efficiency

High purity products even fro

m

feedstocks with high paraffinic contents

High permanent thermal stability

High heat transfer ra

te

No corrosive effect

High chemical stability

Negligible solvent consumption

Low solvent regeneration cost

No toxicity

Low price

Aromatics

ExtractiveDistillationColumn

StripperColumn

Solvent + Aromatics

Solvent

Non-Aromatics

AromaticsFraction

Fig. 5-06Morphylane® Extractive Distillation

Fig. 5-07

Solvent:N-formylmorpholine (NFM)

5.3 Morphylane®

Extractive DistillationDue to lower capital cost andutilities consumption, the Uhde Morphylane® extractive distil-lation process has replaced theformer liquid-liquid extractiontechnology.

5.3.1 Conventional Morphylane® Process

In the extractive distillation(ED) process (see Fig. 5-06),the solvent alters the vapour pressure of the components tobe separated. The vapour pres-sure of the aromatics is loweredmore than that of the lesssoluble non-aromatics. The EDprocess is relatively simple. Thesolvent is supplied to the headof a distillation column via acentral feed inlet. The non-aromatic vapours leave the EDcolumn with some of the solv-ent vapours. The internal refluxis controlled by the solvent feedtemperature. The solvent isrecovered from the overheadproduct in a small column withsectional reflux, which can beeither mounted on the maincolumn or installed separately.The bottom product from theED column is fed to a distil-lation stage, i.e. the stripper, to separate the pure aromaticsand the solvent. After intensiveheat exchange, the lean solventis recycled to the ED column.

The product purity is affectedby a number of different para-meters including solvent select-ivity, the number of separationstages, the solvent/feedstockratio and the internal reflux ratioin the ED column. The solventproperties needed for this pro-cess include high selectivity,thermal stability and a suitableboiling point. The solvent usedin the Morphylane® process isa single compound, namely

N-formylmorpholine (NFM). No agents or promoters areadded to the solvent. Thesalient features of NFM aresummarised in Fig. 5-07.

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23

Non-Aromatics

Aromatics

Solvent

Feed

3

2

1

4

5

5.3.3 Single-Column Morphylane®

Extractive Distillation

Uhde's new Single-Column Morphylane® extractive distil-lation process uses a single-column configuration whichintegrates the extractive distil-lation (ED) column and thestripper column of the conven-tional Morphylane® design. Itrepresents a superior processoption in terms of investmentand operation (Fig. 5-08).

In the Single-Column ED pro-cess, the aromatics are removedfrom the vaporised feed by thesolvent (NFM) in packing 2.Residual non-aromatics arestripped off by aromaticsvapours in packing 3. Solventtraces in the column head are washed back with the non-aromatics reflux in packing 1,while solvent traces in the aro-matics vapours are removed byaromatics reflux in packing 4.

Packings 3 and 4 are separ-ated by a dividing wall formingtwo chambers. The chambercontaining packing 4 is closedat the top side.

The aromatics-solvent mixture draining from the two chambersis fed to the stripping section (packing 5) where the aromatics are stripped off from the solvent.The lean solvent is returned tothe top of the column. Intensivestripping is crucial to the aro-matics yield.

The first industrial realisation of the new concept has been a toluene recovery plant forARSOL Aromatics GmbH inGelsenkirchen, Germany, com-missioned in October 2004.

Based on the Single-Column Uhde Morphylane® processdescribed above, the plantproduces pure toluene fromfully hydrogenated coke ovenlight oil.

The plant has a toluene capacityof 30,000 tonnes/year and itachieves purities of over99.99%. The column has proved easy to operate, evenunder varying feed conditionsand product specifications.

Uhde supplied the licence for the plant, provided engineering services and was on hand ina consulting capacity during commissioning.

In 2005, Uhde was presented with the 'Kirkpatrick HonorAward for Chemical EngineeringAchievement', a biennial awardfor innovative products or pro-cesses by the journal ChemicalEngineering. A vital prerequisitefor submission of an innovationis that its first-time industrial-scale implementation was withinthe past two years. Our techno-logy met this condition with thesuccessful commissioning of thearomatics plant based on theinnovative single-column con-cept for ARSOL AromaticsGmbH in 2004. An internationalteam of experts ranked theprocess among the five bestprocess innovations of the lasttwo years.

Fig. 5-08 Single-Column Morphylane®

Extractive Distillation

5.3.2 Nitrogen Guard Bed

The Morphylane® processwithholds the solvent in theunit almost completely. Theconcentration of NFM in theextract is typically less than 1 wt.-ppm, which correspondsto <0.15 wt.-ppm basic nitrogen.Therefore losses are of no im-portance to the economics ofthe process. However, marketdemands have increased: Dueto the invention and spread ofzeolithe catalysts for alkylationprocesses the requirements forthe extract of the Morphylane®

process have become stricter.The nitro- gen concentration isrequired to be as low as pos-sible. Uhde’s answer to thismarket demand is the NitrogenGuard Bed. This adsorptionbed is able to capture eventraces of basic nitrogen, suchthat the product concentrationis in the ppb-range, below thedetection limit. Therefore aro-matics from the Morphylane®

units can safely be fed to zeolithe-catalysts reactors, producing alkyl-aromatics inworld-scale.

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525,000 mtpy of pyrolysis gasoline extractive distillation for Rayong Olefins Corp., Thailand

24

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FreshToluene

Ben

zene

Col

umn

Xyle

ne R

evov

ery

Col

umn

Deh

epta

nize

r

Sep

arat

or

TDP

Rea

ctor

Sta

biliz

er

Make-upHydrogen

Light Endsto Fuel

Mixed Xylenes toPara-xylene Recovery

Benzene

C9+ Aromaticsto Gasoline Pool

B/T Aromaticsfrom Extraction

Vent

Benzene

Heavy Aromatics Purge

HD

A R

eact

or

C8+ Aromaticsfrom Predistillation

Ben

zene

Col

umn

Rec

ycle

Col

umn

Make-upHydrogen

Sta

biliz

er

Sep

arat

or

Hydrodealkylation and Toluene Disproportionation Technology

25

Fig. 5-09Hydrodealkylation (HDA) Unit

5.4 Hydrodealkylation Technology

Hydrodealkylation, commonlyknown as HDA, is a well-established process for converting C7 and C8 (even upto C9+) alkylbenzenes to highpurity benzene. Very few newplants are being built, how-ever, as the huge hydrogenconsumption makes the ben-zene quite expensive.

The preferred technology usesnon-catalytic thermal reactorsystems which have a highbenzene yield, extremely highon-stream factors and loweroperating costs as comparedwith catalytic systems. A typicalprocess configuration is shownin Fig. 5-09.

Several options, e.g. to enhancebenzene yield or to minimisehydrogen consumption are available, depending on thequality of the feedstock treatedin the HDA. Co-processing C8and even C9+ aromatics willenhance benzene output butwill also increase hydrogenconsumption considerably. An upstream extraction stagereduces the content of non-aromatics to such an extentthat the amount of hydrogenconsumed in the cracking reaction is minimised.

5.5 Toluene Disproportion-ation Technology

Toluene DisproportionationTechnology (TDP) convertstoluene to benzene and mixedxylenes in approximately equi-molar quantities. The reactionis carried out in the vapourphase on a variety of acidiczeolite catalysts. ConventionalTDP produces a xylenes fractionin which the xylene-isomerequilibrium is reached. Thepara-xylene concentration is

therefore limited to 24%. Furtherprocessing is required to in-crease the para-xylene yield.

This involves separating thepara-xylene isomer by select-ively adsorbing or by crystal-lising and isomerising theremaining meta-xylenes andortho-xylenes (optionally) toform para-xylene. Since the

para-xylene concentration inisomerisation is only 24% aswell, a large recycle loop isrequired to completely convertthe undesired isomers to para-xylene.

A major technological break-through was achieved when thezeolite catalyst geometry wasdeveloped to maximise para-

xylene selectivity. The TDP withimproved selectivity produces axylene fraction which containsup to 90% para-xylene.Consequently, the downstreampara-xylene recovery and xyleneisomerisation stages are smallerand more efficient.

Fig. 5-10 shows a typical pro-cess configuration for a TDP.

Fig. 5-10Toluene Disproportionation Unit

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Toluene/C9+ Transalkylation andPara-Xylene Adsorption Technology

26

5.6 Toluene/C9+ Trans-alkylation Technology

In contrast to the TDP, tolueneand C9+ aromatics are con-verted to mixed xylenes in thetransalkylation technology. The xylenes-to-benzene ratioincreases if more C9+ aromaticsare mixed with the toluenefeed and if the transalkylation reaction rate increases. Similarcatalysts to those used in TDPunits are used.

5.7 Para-Xylene Adsorption Technology

Para-xylene can practically notbe separated from meta-xyleneby conventional distillation dueto the closeness of their boilingpoints. In contrast, ortho-xylenecan be recovered by conven-tional distillation because itsboiling point is considerablyhigher than that of the otherisomers.

The most common para-xyleneseparation technology usedtoday involves adsorption usingmolecular sieves.

Crystallisation technology isalso widely used, especially inNorth America and in WesternEurope. However, one of themain advantages of adsorptionover crystallisation is its highrecovery rate per pass

(up to 97%). In contrast, crystallisation units have aeutectic limitation of 65%. All commercialised para-xyleneadsorption processes use iso-thermal, liquid phase adsorp-tion. The adsorbent’s selectivity,capacity and reversibility arethe key properties relevant todesorption.

At the heart of the adsorptionprocess are the adsorptioncolumns in which the followingsteps occur in a sophisticatedsemi-continuous operation:

• feeding in mixed xylenes

• diluting out extract (para-xylene) with a desorbent

• diluting out raffinate (ethyl-benzene, meta-xylene and ortho-xylene) with a desorbent

• feeding in recycled desorbent

Mixed Xylenes fromXylene Splitter

Raf

finat

e C

olum

nEx

trac

t Col

umn Fini

shin

g C

olum

n

Block scheme of theAdsorption System

Desorbent

Light Ends

Para-Xylene(Extract)

C8 -Aromaticsto Isomerisation

(Raffinate)

The diluted extract and raffinatestreams are fractionated in anextraction column and a raffin-ate column to recover the desorbent which is recycledback to the adsorbers.

Any residual toluene containedin the mixed xylenes feed andcarried over with the para-xyleneextracted is separated in a finishing column. The concen-trated raffinate, meta-, ortho-xylene and ethylbenzene, issent to the isomerisation stage.A simplified process configur-ation is shown in Fig. 5-11.

Fig. 5-11Para-Xylene Adsorption Unit

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Xylenes Isomerisation Technology27

5.8 Xylenes Isomerisation Technology

Once the C8 aromatics streamhas been depleted of para-xylene (and optionally of ortho-xylene as well), the stream issent to an isomerisation unit tore-establish the equilibrium ofthe xylene mixture. This occursby converting the meta-xylene(and ortho-xylene, if present)and the ethylbenzene (EB) topara-xylene by isomerisationuntil the equilibrium is reached.The isomerisate is then returnedto the xylene fractionation section in which valuable para-xylene, and optionally ortho-xylene, are recovered. Meta-xylene and EB are returned tothe recycle loop.

Alternatively, EB can be de-alkylated to form benzene andethane.

The method of EB conversionis influenced by the catalysttype. Xylene isomerisationcatalysts can be categorisedaccording to their ability to isomerise EB into additionalxylenes or their ability to de-alkylate EB. Both types ofcatalyst isomerise the xylenesto form a close equilibriumxylene isomerisate mixture.

EB isomerisation catalysts re-sult in the highest para-xyleneyield from a given feedstockdue to the conversion of EB toadditional xylenes. EB isomer-isation is more difficult thanxylene isomerisation and re-quires a bifunctional acid-metalcatalyst. EB isomerisationoccurs using C8-naphtheneintermediates. This type of catalyst must be operated witha substantial concentration ofC8-naphthenes in the reactorrecycle loop to allow efficientconversion of EB to xylenes.

Xylene feedstocks containinghigh EB concentrations, suchas pyrolysis gasoline feed-stocks, are particularly suitableas the EB is converted tonaphthenes thereby producingthe naphthene concentrationrequired. The EB isomerisationconversion rate typicallyamounts to 30 - 35%.

EB dealkylation is not limitedto equilibrium conditions and permits EB conversion rates ofup to 65%. EB dealkylationcatalysts generally contain ashape-specific molecular sievewith a given pore size, whichminimises xylene loss causedby xylene disproportionation,transalkylation or hydrocracking.

3CH

CH3

CH

CH3

CH3

3

CH3

meta-Xylene para-Xylene ortho-Xylene

Xylene Isomers

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6. Operating Results of Extractive Distillation Plants

28

Reformate feed with high aromatics contentTypically, reformates whichcontain large quantities of aromatics are processed inaromatics complexes in whicha high aromatics yield reformeris installed. The C6 core cutcontains aromatics levels whichwell in excess of 50%. Theoperating results of four plantsare summarised in Tables 7-01 and 7-02.

Table 7-01

Reformate feed with high aromatics content

Plant for

Year of commissioning

Benzene in ED-feedToluene in ED-feed

Benzene productionToluene production

Benzene quality

Toluene quality

Solvent loss

Steam consumption

Yield

Japan Energy, Kashima

2007

30%49%

136,000 mtpy223,000 mtpy

max. 400 wt.-ppm non-aromatics

99.0 wt.-%

max. 0.007 kg/t aromatics

480 kg/t ED-feed

Benzene: 99.92%

Repsol, Spain

2007

75%0%

221,000 mtpy-

400 wt.-ppm non-aromatics

-

max. 0.010 kg/t aromatics

470 kg/t ED-feed

Benzene: 99.7%

ED column and stripper, aromatics complexat the Kashima refinery, Japan

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29

Reformate feed with low aromatics contentReformates processed in gas-oline-based refineries generallycontain smaller quantities ofbenzene. Reformers are oftenoperated at lower severitylevels. If the benzene contentof gasoline is to be reduced,the benzene content of the C6core cut fed to the extractivedistillation stage needs to bewell below 50 wt%. In this typeof application, the energy con-sumption of extractive distil-lation processes is lower thanthat of reformate streams witha higher aromatics (benzene)content. Table 7-03 shows theoperating results of two plantsrecently commissioned forbenzene reduction.

Pyrolysis gasoline feedPyrolysis gasoline from steam-crackers has a relatively higharomatics content which is dictated by the cracker feed-stock and the severity of thecracker. The results obtainedfrom an aromatics distillationprocess in a typical naphtha-based steam-cracker are shownin Table 7-04. The two ex-amples are based on a benzeneED, which was started up inthe Netherlands at the end of2002, and a benzene/tolueneED, which went into operationin Poland in 2005.

*) including the benzene/toluene splitter

Table 7-04

Table 7-03

Reformate and pyrolysis gasoline feed with high aromatics content

Plant for

Year of commissioning

Benzene in ED-feedToluene in ED-feed

Benzene productionToluene production

Benzene quality

Toluene quality

Solvent loss

Steam consumption

Yield

PKN Orlen, Poland

2006

33%41%

178,000 mtpy222,000 mtpy

70 wt.-ppm non-aromatics

470 wt.-ppm non-aromatics

0.006 kg/t aromatics

540 kg/t ED-feed

Benzene: 99.9; Toluol: 98.2 %

Shell Moerdijk, The Netherlands

2002

65 wt.-%-

550,000 mtpy-

max. 200 wt.-ppm non-aromatics

-

max. 0.003 kg/t benzene

400 kg / t ED-feed

-

Reformate feed with high aromatics content

Plant for

Year of commissioning

Benzene in ED-feedToluene in ED-feed

Benzene productionToluene production

Benzene quality

Toluene quality

Solvent loss

Steam consumption

BASF Antwerp, Belgium

2000

~ 65 wt.%-

258,000 mtpy-

max. 100 ppm wt. non-aromatics

-

max. 0.005 kg/t benzene

450 kg/t ED-feed

SPC, PR China

1999

~ 75 wt.%~ 85 wt.%

135,000 mtpy65,000 mtpy

max. 80 ppm wt. non-aromatics

max. 600 ppm wt. non-aromatics

max. 0.08 kg/t aromatics

680 kg/t ED-feed *)

Reformate feed with low aromatics content

Plant for

Year of commissioning

Benzene in ED-feed

Benzene production

Benzene quality

Solvent loss

Steam consumption

Holborn Refinery, Germany

2003

~ 27 wt.%

66,000 mtpy

max. 10 ppm wt. non-aromatics

max. 0.002 kg/t benzene

450 kg/t ED-feed

Tonen, Kawasaki, Japan

1999

~ 30 wt.%

100,000 mtpy

max. 50 ppm wt. non-aromatics

max. 0.001 kg/t benzene

380 kg/t ED-feed

Table 7-02

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7. Laboratory, Analyticaland R&D Services

30

The new Uhde research centre

Uhde operates laboratory andpilot plant facilities in Ennigerloh,Germany. The facilities are usedfor ongoing developments tonew processes and for opti-mising established processes.In conjunction with their col-leagues in the central R&Ddivision, a highly qualified teamof 30 employees is committedto providing R&D services forour customers. This team in-cludes:• 12 chemists and chemical

engineers• 10 chemical technicians

and mechanics• 4 administrative staffis committed to providing R&Dservices for our customers.

Using the latest state-of-the-art equipment, our R&D staffis dedicated to:

• improving Uhde processes

• searching for new processes and process opportunities

• improving analytical methodsand preparing analytical instructions and manuals

• providing a wide range of analyses for feedstocks andproducts

• providing analytical supportduring the commissioning of our plants

Our process engineers inDortmund and Bad Soden workclosely with the laboratory staffand are able to support oper-ations whenever needed. Thelaboratory and pilot facilitiesare certified in accordance withISO 9001 to ensure consistentlyhigh standards.

7.1 Analytical facilities

The laboratory consists of 5 working sections:

• laboratory for inorganic chemistry/physical analyses

• gas chromatography• laboratory for fuel and coal

analysis• laboratory for oil and wax

analysis• test laboratory

The analytical facilities permitstandard DIN/ISO or ASTManalyses of virtually any typeof fuel and refinery/petro-chemical feedstock, as well asa variety of inorganic analyticalmethods and water analysismethods. Some of the mainmethods are summarisedbelow.

7.1.1 Gas chromatography

Our laboratory uses gas chromatographs to categoriseall types of hydrocarbon feed-stocks, products and inter-mediate products. The samplesare separated analytically incapillary, widebore or packedcolumns of suitable polarity.Standard analytical methodsusing flame ionisation detectors(FID) and thermal conductivitydetectors (TCD), are enhancedby special detection methodswhich use selective sulphurdetectors (S-CLD) or nitrogendetectors (NPD and N-CLD).Additionally, a powerful GC-MSD system enables us notonly to identify unknown com-ponents in a complex matrix,but also to quantify componentsof special interest even whenpresent as trace amounts.

7.1.2 Physical and chemical methods

Hydrocarbon components arecompletely broken down andother properties and impuritiesare also of interest. We usevarious analytical methods toanalyse these properties andimpurities, including elementalanalyses (CHNS), chloride con-tent, bromine index/number, acidwash colour, specific gravity,molecular weight, acidity, re-fraction index and many more.The methods used include:

• UV-Vis spectroscopy• ion chromatography• atom absorption

spectroscopyy• potentiometry• coulometry• viscosimetry (Hoeppler,

Ubbelhohe, Engler)• ignition point determination

(Abel-Pensky, Pensky-Martens)

• surface tension (DeNouy)• hydrogen/oxygen combustion• water determination

(Karl Fischer)• solidification point acc.

to ASTM D 852• boiling range acc. to

ASTM D 850 and D 1160• total sulphur acc. to ASTM

D 5453 and D 7183• total nitrogen acc. to ASTM

D 6069 and D 7184

7.1.3 Other analytical methods

In addition to the standardanalytical methods mentionedabove, our laboratory is ableto develop other analyticalmethods to cater to specialcustomer requirements, or tosupport troubleshooting in ourcustomers’ plants. This meansthat we can measure:

• thermal stability of chemicals• corrosion of materials in

chemicals• 2-liquid phase separation

abilities• polymer content in solvents• foaming tendencies• chemical stability

7.2 Determination of thermo-physical properties

Simulation models must beconstantly enhanced usingdata gained during plant oper-ation or in laboratory tests toensure the continuous improve-ment of process simulationand equipment design.

Uhde has continuously devel-oped and increased its thermo-physical property data bankswhich are used for processsimulation of its separationtechnologies. Vapour-liquidequilibrium (VLE) or liquid-liquidequilibrium (LLE) data for

Gas-phase chromatographs used in the separation and quantitative analysis of liquid and gaseous samples

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specific solvent/ hydrocarbonsystems (used in ED and LLE)is measured in our labora-tories, evaluated and linked toour process simulators. Simu-lation results can later be verified or checked in our pilotplant facilities under real oper-ating conditions. This procedureallows us to develop tailor-madeseparation processes for ourcustomers.

Uhde’s laboratory includesequipment to:

• determine the VLE data of binary and tertiary systems at temperatures of 20°C-160°C and pressuresof 0-40 bar

• determine the LLE data of binary, tertiary, and quaternary systems at tem-peratures of -40°C to 95°C for 1 bar, and temperaturesof 20°C-160°C for pres-sures ranging from 0-5 bar

• measure crystallisation equilibria

• measure the solubility of gases in liquids

• determine mass transfer coefficients

7.3 Pilot Plant Tests

The Uhde pilot plant tower is a three-storey building situatednext to the laboratory. The 3platforms cover an overallheight of 12 m. Larger pilotplant facilities can be erectedon various other ThyssenKruppsites if required.

The pilot plant is completelysurrounded by scaffoldingmade from Mero cuboid struc-tural components (edge length1 m) and can be accessedevery 2 m to permit simpleand fast installation of equip-ment and bulk.

Most modern DCS and instru-mentation elements are usedfor measuring and controllingthe pilot plant.

A 2-channel gas chromato-graph with FID is used for on-line liquid analysis. Thechromatograph is equippedwith 2 completely separatedsystems of recycle pumps andautomatic liquid injectors.Time-controlled processingand analytical operations areperformed using a computer.

7.3.1 Separation techniques

A variety of fractionation utilities is available:

• conventional distillation with up to 160 theoretical stages. Modules with an ID of 100mm, 72mm, and 50mm made of stainless steel or glass for laboratory-type structured packings (Sulzer DX/EX) and bubble cap trays

• extractive distillation with up to 70 theoretical stages. Modules with an ID of 72mmin stainless steel equipped with structured packings

• liquid-liquid extractors with up to 50 theoretical stages. Modules with an ID of 40 mm in glass equipped with structured packings (Sulzer BX)

• divided wall columns with up to 40 theoretical stages in the partition section.

The operating range can bevaried from a high vacuum to6 bar.

Several types of tubular react-ors, some of which are jacketed,and agitated autoclaves (CSTR)can be used for catalyst andabsorbents testing, and formeasuring reaction kinetics.Pressures of up to 200 barand temperatures of up to 600 °C can be applied to testcatalytic reactions and catalystformulations.

7.3.2 Absorption/adsorptiontechniques

The specially designed equip-ment in our pilot plant facilitiesallows us to test or measurestatic and dynamic absorptionequilibria and mass transferfor gas scrubbers. This equip-ment includes autoclaves, falling-film adsorbers andscrubbers fitted with a varietyof random or structured packings.

Research facility with PC-based process control system forprocess development in the fields of distillation, extractionand extractive distillation

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8. Services for our customers32

Uhde is dedicated to providing its customerswith a wide range of services and to supportingthem in their efforts to succeed in their line ofbusiness.

With our worldwide network of subsidiaries,associated companies and experienced localrepresentatives, as well as first-class backingfrom our head office, Uhde has the idealqualifications to achieve this goal.

We at Uhde place particular importanceon interacting with our customers at an earlystage to combine their ambition and expertisewith our experience.

Whenever we can, we give potential customersthe opportunity to visit operating plants and topersonally evaluate such matters as processoperability, maintenance and on-stream time.We aim to build our future business on theconfidence our customers place in us.

Uhde provides the entire spectrum of servicesassociated with an EPC contractor, from theinitial feasibility study, through financing con-cepts and project management right up to thecommissioning of units and grass-roots plants.

Our impressive portfolio of services includes:

• Feasibility studies/technology selection

• Project management

• Arrangement of financing schemes

• Financial guidance based on an intimateknowledge of local laws, regulations andtax procedures

• Environmental studies

• Basic/detail engineering

• Utilities/offsites/infrastructure

• Procurement/inspection/transportation services

• Civil works and erection

• Commissioning

• Training of operating personnel

• Plant operation/plant maintenance

The policy of the Uhde group and itssubsidiaries is to ensure utmost quality in theimplementation of our projects. Our head officeand subsidiaries worldwide work to the samequality standard, certified according to:DIN/ISO 9001/EN29001.

We remain in contact with our customers evenafter project completion. Partnering is ourbyword.

By organising and supporting technical sympo-sia, we promote active communication betweencustomers, licensors, partners, operators andour specialists. This enables our customers tobenefit from the development of new technolo-gies and the exchange of experience as well as troubleshooting information.

We like to cultivate our business relationshipsand learn more about the future goals of ourcustomers. Our after-sales services includeregular consultancy visits which keep the ownerinformed about the latest developments orrevamping options.

Uhde stands for tailor-made concepts andinternational competence. For more informationcontact one of the Uhde offices near you or visitour website:

www.uhde.eu

Further information on this subject can be foundin the following brochures:

• Edeleanu Refining Technologies• Organic chemicals and polymers

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9. Main referencesJust a few of more than 100 referenceplants in the last ten years

34

Completion Customer Process Prod. Capacity Licensor or Plant Site Plant mtpy Know-how

Morphylane® Extractive Distillation

2010 S-Oil Corporation Benzene/Toluene 680,000 UhdeUlsan, South Korea from Reformate

2010 Tangshan Risun Chemical Company Benzene/Toluene/Xylenes 173,000 UhdeTangshan, China from Coke Oven Light Oil

2010 Qatar Petroleum Benzene/Toluene 762,000 UhdeQatar from Reformate

2010 Atyrau Refinery Benzene 289,000 UhdeKazakhstan from Reformate

2009 Wuhan Iron and Steel Co. Ltd. Benzene/Toluene/Xylenes 94,000 UhdeWuhan, China from Coke Oven Light Oil

2009 Yunnan Dawei Group Co. Ltd. Benzene/Toluene/Xylenes 89,000 UhdeYunwei, China from Coke Oven Light Oil

2009 Tabriz Oil Refining Co. Benzene 33,600 UhdeTabriz, Iran from Reformate

2008 Total Jerp Benzene 140,000 UhdeAl-Jubail, Saudi Arabia from Reformate

2008 Xingtai Risun Coal & Chemical Co. Benzene/Toluene/Xylenes 88,000 UhdeXingtai, China from Coke Oven Light Oil

2008 Jiantao Chemical Co. Ltd. Benzene/Toluene/Xylenes 45,000 UhdeHebei, China from Coke Oven Light Oil

2008 Yunnan Kungang IT Co. Ltd. Benzene/Toluene/Xylenes 44,000 UhdeKunming, China from Coke Oven Light Oil

2008 GCW Anshan I&S Group Co. Benzene/Toluene/Xylenes 128,000 UhdeAnshan, China from Coke Oven Light Oil

2007 Sasol Benzene 100,000 UhdeSecunda, South Africa from Pyrolysis Gasoline

2007 Hood Oil Benzene 110,000 UhdeSanaa, Yemen from Reformate

2007 Shell Eastern Petroleum Ltd. Benzene 210,000 UhdeSingapore from Pyrolysis Gasoline

2007 Japan Energy Co. Benzene/Toluene 360,000 UhdeKashima, Japan from Reformate

2007 Oman Oil Company Benzene/Toluene 350,000 UhdeSohar, Oman from Reformate

2007 Shanxi Sanwei Group Co. Ltd. Benzene/Toluene/Xylenes 178,000 UhdeZhahocheng, China from Coke Oven Light Oil

2006 Copesul Companhia Petroquimica do Sul Benzene 135,000 UhdeTrifuno, Brazil from Pyrolysis Gasoline

2006 Shanghai Baosteel International Benzene/Toluene 68,000 UhdeTaiyuan, China from Coke Oven Light Oil

2006 Repsol S.A. Benzene 221,000 UhdeTarragona, Spain from Pyrolysis Gasoline and Reformate

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Completion Customer Process Feed Capacity Licensor or Plant Site Plant mtpy Know-how

Reformate Hydrogenation

2002 Shell Nederland Chemie B.V. Selective Hydrogenation 850,000 Axens Moerdijk, Netherlands

2000 Saudi Chevron Petrochemical Selective Hydrogenation 860,000 BASFAl Jubail, Saudi Arabia

Pyrolysis Gasoline Hydrogenation

2007 Shell Eastern Petroleum Ltd. First Stage and Second Stage 733,000 AxensSingapore Hydrogenation

2005 CNOOC/Shell Petrochemicals Co. Ltd. Hydrogenation 800,000 AxensHuizhou, China

2005 BASF/Yangzi Petrochemical Co. Hydrogenation 600,000 BASFNanjing, China of Pyrolysis Gasoline

2003 Bouali Sina Petrochemical Co. First Stage Hydrogenation 139,000 AxensBandar Imam, Iran Second Stage Hydrogenation 106,000

2001 BASF / FINA First Stage Hydrogenation 795,000 BASFPort Arthur, Texas, USA Second Stage Hydrogenation 563,000

Coke Oven Light Oil Hydrorefining

2010 Tangshan Risun Chemical Co. Hydrorefining 200,000 Uhde/BASFTangshan, China

2009 Wuhan Iron and Steel Co. Ltd. Hydrorefining 100,000 Uhde/BASFWuhan, China

2009 Yunnan Dawei Group Co. Ltd. Hydrorefining 100,000 Uhde/BASFYunwei, China

2008 Xingtai Risun Coal & Chemical Co. Hydrorefining 100,000 Uhde/BASFXingtai, China

2008 GCW Anshan I&S Group Co. Hydrorefining 150,000 Uhde/BASFAnshan, China

2007 Shanxi Sanwei Group co. Ltd. Hydrorefining 200,000 Uhde/BASFZhahocheng, China

Divided Wall Column Distillation and Single-Column Morphylane®

2000 Saudi Chevron Petrochemical Divided Wall Column Distillation 140,000 BASF/UhdeAl Jubail, Saudi Arabia

1999 VEBA OEL AG Divided Wall Column Distillation 170,000 BASF/UhdeMünchsmünster, Germany

2004 Aral Aromatics GmbH Single-Column Morphylane® 28,000 UhdeGelsenkirchen, Germany Toluene from Coke Oven Light Oil

Isomerisation, Transalkylation, Adsorption

2004 Bouali Sina Petrochemical Co. p-Xylene Adsorption 428,000 AxensBandar Imam, Iran

2004 Bouali Sina Petrochemical Co. Xylenes Isomerisation 1,970,000 AxensBandar Imam, Iran

2004 Bouali Sina Petrochemical Co. Transalkylation 883,000 SinopecBandar Imam, Iran

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