Axens’ Portfolio of Selective Hydrogenation Catalysts
Axens
Axens North America, Inc
89, bd Franklin Roosevelt - BP 50802 92508 Rueil Malmaison Cedex - France Tel.: + 33 1 47 14 21 00 Fax: + 33 1 47 14 25 00
Houston Office 1800 St. James Place, Suite 500 Houston, TX 77056 - USA Tel.: + 1 713 840 1133 Fax: + 1 713 840 8375
www.axens.net
The cracked hydrocarbons are recovered in the ethylene plant separation train as different streams that include ethylene, propylene, C 4 cuts and pyrolysis gasoline (C 5+). These different cuts are usually purified by selective hydrogenation to eliminate undesirable by products or impurities.
Axens’ Portfolio of Selective Hydrogenation Catalysts Introduction
Selective hydrogenation of FCC C 4, C5 and naphtha cuts allows improved downstream plant operations, productivity and product quality.
Selective hydrogenation catalysts are used mainly for the purification of steam-cracker streams although they are also employed to treat FCC effluents. The main objective of a steam-cracker is to produce ethylene, which is accompanied by important co-products such as propylene, butenes, butadiene, and aromatics. Steam cracker feedstocks originate from a wide variety of sources that include ethane, propane, naphtha and gas oils.
Axens offers a large portfolio (figure 1) of industrially proven, efficient and cost-effective selective hydrogenation catalysts that allow the customers to stay competitive in a rapidly evolving market. These catalysts are perfectly suitable for all types of selective hydrogenation units.
Figure 1 - Axens’ Portfolio of Selective Hydrogenation Catalysts for Steamcrackers Effluents
2
Selective Hydrogenation of C2 Cuts
Liquid phase hydrogenation
Raw C2 cuts contain between 0.5 and 2% acetylene, which inhibits ethylene polymerization catalysts. The aim of C 2 cut selective hydrogenation is to reduce acetylene content as low as possible while maximizing ethylene yield and minimizing oligomer (green oil) formation.
LD 273 catalyst has been developed specifically to obtain high propylene yields. Through optimized chemical and structural characteristics, LD 273 achieves efficient MAPD conversion, typically to less than 1 ppm, and propylene yields surpassing 100%, green oil formation is suppressed and overhydrogenation to propane is minimized.
Axens’ catalyst for selective hydrogenation of C2 cuts, LT 279, is a promoted, low palladium catalyst, supported on a special high purity alumina. The highly efficient LT 279 reduces acetylene concentrations to less than 1 ppm at low operating temperatures, providing outstanding ethylene yields, typically superior to 100%. Moreover, it drastically reduces green oil production which results in very long cycles. In front-end operations (treatment of C 2cuts), its low tendency towards runaway reactions is a further advantage.
LD 273’s commercial performance compares well with that of its successful predecessor, LD 265. Both catalysts demonstrate very efficient MAPD removal, with effluent concentrations around 1 ppm, with typical MAPD conversions exceeding 99.99%. The catalysts, however, have different palladium (Pd) contents; LD 273 contains less Pd than LD 265 and yet its selectivity is remarkably better as Figure 2 illustrates. Propylene Concentration, %
Table 1 shows the performance of LT 279 in a typical commercial unit. Ethylene yield is increased while acetylene is virtually eliminated. Low acetylene content
High acetylene content
Acetylene in feed, wt%
0.95
1.28
Acetylene in outlet, ppm
<1
<1
Ethylene in feed, wt%
81.4
83.2
Ethylene in outlet, wt%
81.9
83.9
100.6
100.8
Ethylene yield,%
96
= 1.0%
94
95.5 94.5 94.0
92 Feed
LD 265
LD 273
Reactor Effluent
Figure 2 - Increased propylene concentrations after 99.996% MAPD conversion
Table 1 - Commercial performance of LT 279
The higher propylene concentration in the pro pylene/propane splitter feed makes the splitter’s task easier. In fact, some customers were even able to shut down their splitter because simple replacement of the existing catalyst by LD 273 was enough to meet the required propylene purity.
Selective Hydrogenation of C3 Cuts Typical steam cracker C 3 cuts contain 90% propylene and 2 to 6% methyl acetylene and propadiene (MAPD) which must be completely removed to meet propylene product specifications. To eliminate MAPD, maximize propylene yield and suppress oligomer (green oil) formation, a selective hydrogenation process is applied to the C 3 cut.
The comparison given in Figure 3 shows that the propylene yield increases by 1.1% after replacement of LD 265 by LD 273.
From a process point of view, selective hydrogenation can be carried out in either liquid or vapor phase. Axens has developed a specific catalyst for each option.
3
Propylene Yield, %
In refineries, selective hydrogenation of a FCC C4 cut results in reduced acid consumption in downstream alkylation plants and increased MON of HF alkylate. TAME unit feedstocks, containing essentially C5 compounds, can be upgraded by means of selective hydrogenation, in order to limit gum formation in the downstream TAME unit and to increase TAME production. Axens has developed optimized catalysts for each processing option.
102.0
= 1.1%
101.0
101.6
100.5 100.0
LD 265
Selective hydrogenation of acetylene com pounds in raw C 4 cuts for butadiene recovery
LD 273
Figure 3 - Increased propylene yield with LD 273
The selective hydrogenation process to convert vinyl acetylene (VAC) and 1-butyne or ethyl acetylene (ETAC) improves the efficiency and economics of downstream butadiene extraction processes.
LD 273 obtains better performance, reducing oligomer and polymer formation by 40%. These materials hinder a reactant’s access to the catalyst’s active sites and stifle the hydrogenation reactions. Also, LD 273 maintains its high performance longer, extending the cycle length.
LD 277 is the ideal catalyst for this application, achieving high acetylenes’ hydrogenation activities and high butadiene yields as illustrated in Figures 4 and 5. In addition, long catalyst lifetimes are typical. LD 277 is applied in two process configurations, with or without an acetylene removal column in the downstream extraction unit. Figure 4 shows feed and product butadiene concentrations in a commercial unit having acetylene removal columns.
Vapor phase hydrogenation Axens catalyst for vapor phase processes, LT-279, makes use of promoted Pd on a high purity alumina carrier. LT 279 features highly efficient MA and PD conversion even at low operating temperatures, outstanding propylene selectivity and a drastically reduced green oil formation, which results in very long cycles
Butadiene content, %
The following table shows the typical performance of a commercial LT 279 unit for vapor phase hydrogenation of C 3 cut. Feed
Product
Propylene,% wt
91.2
93.4
Propane,% wt
5.3
6.6
MA, ppm wt
23 000
<1
PD, ppm wt
12 000
< 10
Propylene yield,%
102.4
MAPD conversion,%
99.97
47
46
45
Feed
Effluent
Figure 4 - Selective hydrogenation with acetylene removal columns (LD 277)
Table 2 - Commercial performance of LT 279
If acetylene removal columns are available downstream from the hydrogenation unit, VAC and ETAC conversions can be limited to 50% as shown in Figure 5.
Selective Hydrogenation of C4 and C5 Cuts There are several processing options for the upgrading of a typical steam-cracker C 4 cut containing around 50% butadiene, 25% isobutene, 20% butenes and 2% acetylenes, depending on the market for the various C 4 components.
4
VAC Content, %
losses by a factor of ten. Lifetimes of several years can be typically achieved. Moreover, LD 277 tolerates the sulfur compounds that can appear during plant upsets and which act as inhibitors. The initial activity can be recovered simply by restoring the feedstock quality to its original specifications.
2.5 2.0 1.5 1.0 0.5 0
Feed
Effluent
Selective catalysts for butenes and iso-amylenes
Figure 5 - VAC conversion for unit configured with acetylene removal columns (LD 277)
100
Conventional Pd-only catalysts have poor butene-1 selectivity because they significantly promote 1-butene isomerization to 2-butene. Axens therefore developed LD 271, a special catalyst based on Pd and a promoter on an alumina carrier, endowing the catalyst with very high intrinsic selectivity. Axens’ LD 271 is suitable for the two major processing options concerning 1-butene recovery:
80
60
40
20
0
Product
Figure 6 - Butadiene content still remains high without acetylene removal columns (LD 277)
-
hydrogenation of raw C 4 cuts containing around 50% butadiene, - processing of C4 cuts after butadiene extraction, containing around 1% butadiene.
With no acetylene removal columns available, the acetylenes have to be converted more thoroughly to 100 ppm as seen in Figure 7.
In both cases the targets are the same: reducing butadiene content to the ppm range, achieving high 1-butene yields, and minimizing 2-butene and butane formation.
VAC & ETAC Content, % 1.2 1 0.8
Even for a very severe product specification of less than 2 ppm butadiene, about 50% of the butadiene is converted to 1-butene, as shown by the following industrial results for a butadiene-rich unit.
0.6 0.4 0.2 100 ppm 0
Feed
of
Selective catalyst for 1-butene production
Butadiene Content, %
Feed
production
Effluent
Figure 8 shows relatively steady concentrations of butadiene and 1-butene in the feed over a four-year period.
Figure 7 - Acetylene conversion in a unit configured with no acetylene removal columns (LD 277)
Concentration in Feed, wt %
In either case, LD 277 meets the specified conversion of acetylenes while attaining high butadiene yields, around 101% and 93% respectively.
60
Butadiene 50 40 30
Beyond activity and butadiene yield, catalyst stability is a key feature for this kind of application, since VAC reacts with Pd to form a soluble complex. Conventional Pd catalysts thus rapidly lose their Pd through leaching, resulting in very short lifetimes, typically a few months, and in high costs.
Figure 8 - Butadiene and 1-butene concentrations in feed to hydrogenation unit (LD 271)
LD 277 is a bimetallic catalyst, for which the Pd is stabilized by a dopant that reduces Pd
Figure 9 shows that, for the same period, the 1-butene concentration after the hydrogenation
20
1-Butene
10 0 0
500
1000
1500
Days on stream
5
step is generally over 30%, i.e., two or three times the concentration in the feed. The 1 butene increase is around 23% which corresponds to about 50% of the butadiene in the feed. Butadiene concentration in the product has remained consistently less than the 2 ppm maximum specification. 1-Butene Concentration, wt %
Butadiene in Butenes Product, ppm 1-Butene
40
Feed
Product
Butadiene, ppm
650
<10
1-Butene, wt%
22.2
3.2
Trans 2-Butene, wt%
14.1
26.7
cis 2-Butene, wt%
9.3
13.6
i-Butene, wt%
44.8
44.1
n-Butane, wt%
7.5
9.8
i-Butane, wt%
2.1
2.6
4.0
Butadiene conversion, %
30
3.0
20
2.0
Butadiene 10
Isomerization rate, %
85.6
Olefin yield, %
96.9
i-butene yield, %
98.4
Table 3 - Commercial performance of LD 267 R Catalyst
1.0
0
>98.5
0 0
500
1000
1500
High sulfur tolerance for butenes and isoamylenes recovery
Days on stream
Figure 9 - 1-Butene and butadiene concentrations in butenes after hydrogenation of 1,3 butadiene
FCC C4 cuts often contain sulfur compounds to such an extent that conventional Pd catalysts suffer from severe deactivation, resulting in low butadiene conversion. The consequences can be high acid consumption and equipment fouling in downstream alkylation units, causing operating problems and higher costs.
Hydroisomerization catalyst for production of 2-butenes LD 267 R is the catalyst of choice when high 2-butenes yields are essential, for example, upgrading steam-cracker C 4s to 2-butene, pretreatment of HF alkylation unit feedstocks from an FCC unit or pretreatment of feed to an Axens’ Isopure unit.
TAME unit feedstocks, containing essentially C5 compounds, can be upgraded by means of selective hydrogenation of C 5 diolefins in order to limit gum formation in the TAME unit. Gums cause shorter cycles and product discoloration. Another benefit of selective hydrogenation is that TAME production increases through an increased reactive isoamylenes yield. In this application too, high sulfur content feedstocks can deactivate conventional Pd catalysts.
LD 267 R achieves efficient residual butadiene removal with a high isomerization of 1-butene to 2-butene that approaches the thermodynamic equilibrium. Over-hydrogenation to butanes is held to a minimum. The catalyst’s selectivity for isomerization and olefin recovery is obtained by a specific pretreatment step that moderates the catalyst hydrogenation activity. A further advantage of this pretreatment is that the catalyst is delivered in its reduced form. The result is that the activation step during start-up can be performed quickly and easily.
LD 2773 is a promoted Pd catalyst, specially designed for high sulfur feedstocks. The promoter confers on LD 2773 an exceptional tolerance towards sulfur compounds contained in C4 and C5 cuts.
Table 3 shows the performance of a typical commercial unit containing LD 267 R catalyst.
6
Table 4 shows typical performance obtained by pretreatment with LD 2773 on feed to a commercial TAME unit. Feed
Product
Sulfur content, ppm wt
90
90
Diolefins,% wt
0.9
0.015
3-methyl-1-butene,% wt
1.7
0.6
2-methyl-1-butene,% wt
9.4
7.1
2-methyl-2-butene,% wt
17.2
20.7
Diolefins conversion,% Reactive amylene yield,%
petrochemical end use. Two process schemes are possible: 1. First stage pygas hydrogenation – This involves selective hydrogenation of most of the diolefins and alkenylaromatics in order to meet gasoline pool stability specifications. 2. Second stage pygas hydrogenation – following the first stage hydrogenation, this process removes the remaining diolefins, alkenyl-aromatics and olefins without aromatics hydrogenation, followed by desulfurization to meet high purity aromatic product specifications.
98 104.5
Table 4 - Performance obtained with LD 2773 on feedstock to a commercial TAME unit
The trend toward more stringent environmental regulations concerning gasoline has led to a reduction in the amount of pygas in the gasoline pool and to an increase in its use as a petrochemical feedstock.
The results show that LD 2773, despite the high sulfur content, efficiently and selectively hydrogenates the diolefins and increases the overall yield of the two amylene isomers used for TAME production, namely 2-methyl-1 butene and 2-methyl-2-butene.
Axens offers highly active, selective and stable catalysts for both options.
Total saturation to butanes
First stage pygas hydrogenation process
Taking into account the butadiene surpluses that have arisen in several countries, naphtha cracker operators have to find ways other than butadiene extraction to upgrade their C4 cuts. Total saturation of a C 4 olefins cut to a stream containing mainly butanes is one of the options. This stream can then be recycled to the cracking furnaces as its ethylene yield is higher than that of naphtha. Another option is to sell it as LPG.
Both Pd and nickel (Ni) catalysts are able to carry out the required reactions, i.e., the selective hydrogenation of diolefins and alkenylaromatics such as styrene, while minimizing olefin hydrogenation and avoiding aromatics hydrogenation. Nevertheless, the performance of Pd and Ni catalysts differs slightly in several respects:
1. Activity: Pd is intrinsically more active than Ni. High activity catalysts are therefore based on Pd. Switching from a conventional to a highly active catalyst could enable a variety of objectives to be achieved such as more stringent specifications, increased unit throughput, increased catalyst cycle-length and lifetime, reduced catalyst inventory provided that unit equipment ca pacities and reactor hydrodynamics are sufficient.
LD 265 is a Pd based catalyst characterized by an efficient hydrogenation activity and high long-term stability. Depending on the process conditions, a wide range of residual olefin contents can be attained, from a few ppm to several per cent. Typically, cycle lengths of more than two years are reached.
Selective Hydrogenation of Pygas cuts Pyrolysis gasoline (pygas) cuts are characterized by high aromatics content and by chemical instability, due to the presence of highly unsaturated compounds such as diolefins and alkenylaromatics.
2. Start-up behavior Fresh nickel catalysts containing insufficient levels of sulfur may be prone runaway reactions during start-up due to the presence of active sites for which the aromatics hydrogenation activity is too high.
Options for pygas upgrading include preparing it for use as a gasoline pool component or recovering the aromatics in the pygas for
7
Therefore, nickel catalysts must be inhibited prior to start-up, by deposition of a sufficient quantity of sulfur on the most active sites. This sulfur pretreatment can be carried out either ex situ, making the startup safe and quick, or in situ.
Axens has extensive commercial experience with both Ni and Pd catalysts, including several commercial references of Pd/Ni stacked beds, and was the first catalyst manufacturer to bring both Pd and Ni catalysts to the marketplace for first stage hydrogenation units.
The reliable and efficient ex situ pretreatment developed by Axens and Eurecat for nickel catalysts is called Resucat TM.
LD 265 (based on Pd) and LD 241 (based on Ni) are Axens’ first generation catalysts. They rapidly became the industry benchmarks owing to their successful and dependable operation and their, having achieved consistent customer satisfaction around the world.
On the other hand, Pd catalysts are intrinsically selective and avoid aromatics hydrogenation.
Based on industrial feedback and extensive research and development efforts, Axens has more recently developed a new generation of catalysts, Pd-based LD 365 and Ni-based LD 341. Through improved physical and chemical characteristics, LD 365 and LD 341 achieve highest of performance levels:
3. Sensitivity to poisons Nickel catalysts contain 20 to 50 times more active metal atoms than Pd catalysts. For this reason, Ni catalysts are more tolerant to poisons than Pd catalysts, and therefore they are preferred in case of highly contaminated feedstocks. Arsenic and mercury can be present in pygas mainly when natural gas condensate are used as feeds to steam crackers; such contamination occurs more rarely when regular naphtha is processed. Silicon contamination is often related to the co processing of imported feedstock stemming from coker or visbreaker units.
-
high conversion of diolefins, styrenes and indenes no conversion of aromatics low deactivation rates long cycles very good mechanical properties full regeneration potential
Axens’ portfolio of first stage hydrogenation catalysts is exhibited in Table 5.
4. Sensitivity to sulfur compounds Ni catalysts are more sensitive than Pd catalysts to mercaptans, disulfides and thiophenes contained in feedstocks. For feedstocks with high sulfur content, Pd catalysts are generally preferred. 5. Cost Ni is generally less expensive than Pd. Pd catalysts contain in general between 0.2 0.5% wt of the precious metal, whereas Ni catalysts contain between 10 - 20% wt of Ni.
Relative Cycle activity Relative length,* per years LHSV volume
Trade name
Metal
LD 265
Pd
2
1.5 - 2
0.8 - 1.5
LD 365
Pd
3
2.5 - 3
1-2
LD 241
Ni
1
1
0.5
LD 341
Ni
2
1.5 - 2
0.8 - 1.5
* Values obtained on full range gasoline i.e., C 5-200 °C
Table 5 - First stage hydrogenation catalysts
Commercial experience with LD 365
In conclusion, the choice between Pd and Ni catalysts depends on several site-specific constraints among which are: feedstock characteristics, product specifications, unit characteristics, Pd vs. Ni price differential.
There are many successful commercial applications of LD 365. A typical example is a pygas unit in Germany designed by others. This unit features a single first stage reactor catalyst bed with no quench and a liquid recycle stream distributed on the top of the bed. Before switching to LD 365, the unit operated using LD 265. The average feedstock characteristics are given in Table 6 and the average first cycle results are compared in Table 7.
A further option is to load the reactor with stacked beds: Pd catalyst on top and Ni catalyst at the bottom of the reactor. The advantage of this option is that it combines the benefit of the Pd catalyst’s higher activity with the abovementioned advantages of Ni catalysts.
8
Diene value, g I2/100 g
25
Bromine number, g Br 2/100 g
70
Sulfur, ppm
60
LD 365 was developed not only to improve diolefins hydrogenation activity but also to improve the hydrogenation of styrene contained in the pygas. Figure 11 presents commercial results and shows that with LD 365, styrene conversion levels are maintained between 80 and 90%. These levels are much higher compared to LD 265, for which a maximum 70% styrene conversion was possi ble. The improved styrene conversion is beneficial for the second stage hydrogenation cycle lengths.
Table 6 - Average feedstock characteristics LD 265
LD 365
1
0.5
Bromine number, g Br 2/100 g
60
60
Aromatics loss,%
0
0
First cycle, days
200
> 300
Diene value, g I2/100 g
Table 7 - Effluent characteristics and first cycle length for LD 365 compared to LD 265
Styrene Conversion, % 100 90
The specified product Diene Value (DV) of 1.2 g I2 / 100 g was reached in the past without problem with LD 265 catalyst, for a product DV of 1. Switching to LD 365 enabled the DV to be cut in half. The operator now enjoys a substantially longer cycle because the rate of pressure drop increase in the second stage reactor is considerably slower.
80 70 60 50 0
250
300
The objectives set by the customer have been met successfully as depicted in Figure 12. The first cycle reached with LD 341 was nine months, whereas a six-month cycle with LD 241 was typical in the past. This 50% increase demonstrates the higher activity and stability of LD 341, resulting lower start-of-run temperatures and lower deactivation slope.
Customer’s EOR Criterion
LD 265 End of Cycle 300
200
Longer cycles with LD 341 The following example concerns a first stage pygas hydrogenation unit that was operated satisfactorily for many years with LD 241, reaching the desired specification. Informed of the new catalyst’s higher activity and resistance to heavily contaminated feeds, the customer decided recently to switch to LD 341. The ob jectives were to achieve longer cycles and to operate the unit under similar conditions.
End of Cycle Due to Steam Cracker Shutdown
200
150
Figure 11 - Commercial performance of LD 365
LD 365 Reactor Inlet Temperature
100
100
Days on stream
Figure 10 shows the temperature variation at the reactor inlet versus time. The End-of-Run (EOR) temperature limit set by the operator for this unit is 85 °C. With LD 265, this level was reached after 200 days of operation. The first cycle of LD 365 catalyst was terminated after 300 days on stream. This occurred before the EOR limit was reached in order to allow for the steam cracker turnaround. The curve has been extrapolated to show that a cycle of 400 days, twice that which was obtained with LD 265, would have occurred. Further cycles have since confirmed the full regenerability and outstanding stability of LD 365. A unit designed by Axens with a higher EOR temperature standard would have taken even further advantage of the excellent performance of LD 365 catalyst.
0
50
400
Days on Stream
Figure 10 - Improved stability of LD 365 versus LD 265
9
Pressure Drop, bar
First Cycle Length, Months
0.80
10
0.60 8
0.40 6
0.20
4
0.00 0
2
50
100
150
200
Days on stream
Figure 14 - Pressure drop in first stage pygas unit using LD 341
0
LD 241
LD 341
Figure 12 - LD 341 extends cycle length by 50%
Second stage pygas hydrogenation process The second stage pygas hydrogenation process serves to hydrogenate any traces of diolefins, and the remaining olefins. It also completes the hydrodesulfurization (HDS) process in order to meet aromatics purity specifications.
High activity and long cycles even with heavily contaminated feedstocks The high tolerance of LD 341 to catalyst poisons was demonstrated recently in a first stage pygas hydrogenation unit processing gasoline containing arsenic in the 50 to 300 ppb concentration range. Due to the high arsenic content, the Pd catalyst originally planned for the unit would have experienced very short one-month cycle lengths. In order to reach acceptable cycle lengths, LD 341 was installed and the unit has since operated with great success: a first cycle of one year has been reached.
Axens strongly recommends a dual bed for the second stage reactor that has a layer of LD 145, a special NiMo catalyst, placed on top and a layer of HR 406, a CoMo catalyst, placed underneath. The purpose of the LD 145 layer is to ensure that all traces of diolefins and a large part of the olefins are converted before the flow reaches the layer of HR 406, a well-proven HDS catalyst that has an acidic alumina sup port. The acidic function of HR 406, necessary for complete HDS, also accelerates polymerization of unsaturated compounds. The polymerization products (gums) formed would foul the catalyst and cause a rapid increase in pressure drop.
Data shown in Figure 13 for the first six months of the cycle demonstrate the efficient styrene removal capacity of LD 341. The average styrene concentration in the feed was reduced from 3.7% to less than 0.5%. Styrene Concentration, wt% 5
Both catalysts are characterized by high activities, low deactivation rates, very good mechanical properties and full regenerability.
Average inlet styrene content
4 3 2
Styrene Content in Outlet
1
Performance of stacked-bed commercial units containing LD 145 and HR 406
0 0
50
100
150
200
The excellent performance of the LD 145 and HR 406 stacked bed system is illustrated by the following commercial data (figure 15, 16 and 17), obtained from a second stage pygas hydrogenation unit started-up recently and still running as of this date.
Days on stream
Figure 13 - Consistent styrene removal effectiveness using LD 341 in a first stage commercial pygas unit
Styrene polymerizing on the catalyst and causing pressure drop is a leading cause for ending the run. Figure 14 presents the pressure drop data for the same time period as represented in Figure 13 and demonstrates that the pressure drop remained stable.
Data for the first four months after start-up are reported and the following observations are noted as follows: -
10
no reactor inlet temperature increase has been necessary during this time
-
Axens for Advanced Catalytic Solutions
pressure drop increase is less than 0.05 bar very efficient sulfur removal, as shown by the outlet thiophene content of less than 0.05 ppm wt.
The catalysts described in this brochure are enjoying considerable commercial success. In fact, over the years Axens has become the world’s leading supplier of hydrogenation processes. There are many reasons for this enviable position: State-of-the-art production facilities in Savannah, Georgia and Salindres, France R&D support from one of the largest and most capable organizations in the world Huge bank of experience and industrial feedback acquired in a period of over fifty years Extensive and responsive worldwide sales network We are determined to enhance our position by offering our customers continuously improved, reliable, and up-to-date products and services.
Reactor inlet temperature, °C 282 281 280 279 278 277
•
276 275 0
500
1000
1500
2000
2500
•
3000
Hours on stream
Figure 15 - Constant activity of LD 145 and HR 406 in stacked bed reactor system
•
•
Pressure drop, bar 0.8
0.7
0.6
0.5
0.4 0
500
1000
1500
2000
2500
3000
Hours on stream
Figure 16 - Pressure drop through LD 145 and HR 406 stacked bed reactor system Thiophene in Outlet, ppm wt. 0.10 0.08 0.06 0.04 0.02 0 0
500
1000
1500
2000
2500
3000
Hours on stream
Figure 17 - Very low thiophene concentration in effluent from LD 145 and HR 406 stacked bed system
V P P / 3 0 0 2 l i r p A
11
