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Aromatics
Uhde
Thys
senK
rupp
A companyof ThyssenKrupp
Technologies
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.
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.
4
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
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
7
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.
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.%
9
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
10
11
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.
12
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
13
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
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)
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
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
17
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
18
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
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
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.
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).
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.
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.
525,000 mtpy of pyrolysis gasoline extractive distillation for Rayong Olefins Corp., Thailand
24
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
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
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
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
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
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
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
33
9. Main referencesJust a few of more than 100 referenceplants in the last ten years
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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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