KR19990022632A - Reverse Step Method in Hydroprocessing Reactor System - Google Patents

Abstract

The present invention relates to a reverse step process for obtaining high conversion, proactive hydrotreatment and product selectivity in a hydroprocess reactor system.

Description

Reverse Step Method in Hydroprocessing Reactor System

There are two conventional methods for obtaining high conversion in petroleum hydroprocessing / hydrogenation techniques. High conversion includes removal of sulfur, removal of nitrogen, hydrocracking, reduction of bottom carbon, and the like. Two conventional methods include (a) a long residence time or low space velocity reaction, or (b) a separate reaction loop for the high conversion step after the feed impurities are reduced in the initial reaction loop.

The second approach, using a separate reaction loop, is effective. This is because removed feed impurity by-products such as H ₂ S, NH ₃ are not present in high concentrations in the first reaction loop. If present in high concentrations, it tends to interfere with the rate of reaction in the second reaction loop.

There are several conventional approaches to obtaining good product selectivity in the prior art. Selectivity includes the desired yield of intrinsic boiling range materials. These conventional methods include (a) recycling undesired products for reprocessing with fresh feed or (b) reprocessing undesirable products in a separation reaction loop. In the prior art, a general approach for selective hydroprocessing for intrinsic boiling range products is to overtreat the entire feed at the point where the most difficult product encounters, or (b) gradually reduce the total amount of feed and separate hydrotreatment of the unusual product. Blocking access to the most difficult product.

Hydrogenation processes that avoid the drawbacks of known processes and achieve higher conversion or deeper processing methods would be preferred.

Summary of the Invention

The present invention maintains the advantages of multi-loop systems that include catalysts applied for higher reaction rates or pretreated feeds, but is provided to achieve these goals at a lower cost in a single reaction loop than in multiple loops.

The present invention provides high performance in a hydroprocessing reactor system comprising performing a high conversion or in-depth process in a lead reactor or top layer of a reactor in a series of reaction loops in a single reactor loop and followed by a general feed in subsequent reactor zones. Reverse step methods for achieving conversion, selective hydrotreatment and product selectivity.

The present invention relates to a hydrogenation process method. In particular, the present invention relates to a hydrogenation process method having high conversion, high product selectivity and capable of selective hydrogenation of products in the intrinsic boiling range.

Figure 1 shows one aspect of the process flow diagram of the invention using a common vessel for the installation of different treatment zones.

2 shows an alternative embodiment showing the process flow diagram of the invention using a separate vessel for the installation of different treatment zones.

Detailed description of the drawings

It will be apparent to those skilled in the art of oil refining that the modifications of the methods described in the specification and shown in the drawings are within the scope of the invention.

A. Figure 1

As described in the process flow diagram of FIG. 1, the catalytic reaction used in the process takes place in two reaction zones 3 and 10. The vessel 2 comprises reaction zones 3 and 10. The initial process takes place in the second zone 10 and the high conversion process takes place in the first zone 3. Optionally, the process flow chart includes preheating of the liquid and gas supply to the reactor (preheater not shown), ammonia and hydrogen sulfide removal and zone 20 for cooling and separating the eluate, optional recycle gas purification zone ( 31) and other features common to hydrogenation processes such as recycle streams 30 and 32, and product separation and distillation zone 40. Liquid bottoms stream 50 from distillation zone 40 and / or by-product or intermediate 52 are combined with stream 54. Stream 54 passes through reaction zone 3. A supplemental hydrogen stream 60 is added to the gas recycle stream 32 (also referred to as hydrogen / light hydrocarbon stream 30 or hydrogen sulfide removal zone eluate 32). Optionally, supplemental hydrogen stream 70 is added to feed stream 1 instead of or in addition to adding supplemental hydrogen to stream 32.

Hydrocracking or deeper hydrotreating takes place in the reaction zone 3 depending on the type of catalyst used in the reaction zone. The eluate 65 in the reaction zone passes through the reaction zone 10. Fresh feed 1 is introduced at the midpoint between the reaction beds 3 and 10. It proceeds in the presence of eluate 65 from the upper reaction zone 3. The eluate 65 also acts as an endothermic portion for exothermic reaction in the reaction zone 10.

Eluate 15 from bottom region 10 is treated for removal of ammonia and hydrogen sulfide in region 20. Water washing, which is a common method, is used for the removal of ammonia and hydrogen sulfide. Zone 20 is also the cooling and separating zone where gas stream 30 is produced and is a liquid stream containing dissolved gas 35. Conventional processes are used in the separation process in zone 20 and the correlation of ammonia and hydrogen sulfide removal. The zone 20 may comprise multiple units or secondary zones according to conventional means for carrying out the removal, cooling and separation of ammonia and hydrogen sulfide. Hydrogen-rich gas stream 32 is recycled to the reactor and mixed with supplemental hydrogen stream 60 again. Mixing the hydrogen enriched gas stream 32 and the supplemental hydrogen stream 60 is optionally or additionally performed, and the supplemental hydrogen stream 70 is mixed with the oil feed stream 1. Recycle gas 30 in stream 30 is optionally purified, such as an amine adsorbent, for example for hydrogen sulfide removal in zone 31 before being recycled to the reactor. The recycle gas of stream 30 (or stream 32, if further refined in zone 31) is optionally injected into stream 54 for injection into the first reaction zone 3 or into the second reaction zone 10. To pass with stream 34.

B. Figure 2

The description of FIG. 2 is the same as that of FIG. 1 except for the following differences. In Figure 1 a general vessel was installed in the reaction zone. In FIG. 2, separation vessels 2 and 9 comprise reaction zones 3 and 10, respectively. In FIG. 1, there is a regeneration gas purification region 31. In FIG. 2, this purification unit 32 is omitted.

A. Overview of Process: Upper and Lower Reaction Zones

The present invention is directed to a reverse stage process for hydroprocessing a hydrocarbon feed to achieve high conversion, selective hydrotreatment and product selectivity in a hydroprocess reactor system. The process involves passing a hydrocarbon feed to the first hydrotreatment zone, such as the denitrification and desulfurization zones. Hydrocarbon feeds in this region are brought into contact with hydrotreating conditions such as denitrogen and desulfurization conditions with hydrotreating catalysts such as denitrogen and desulfurization catalysts. After this contact, the eluate in the dewaxing and desulfurization zone is recovered.

The denitrogen and desulfurization zone eluate is again passed through the purification / cooling zone (also called NH ₃ and H ₂ S and cooling zone). In general, ammonia and H ₂ S are removed by washing with water. Eluate is cooled using conventional means such as heat exchangers. Recovered from the purification / cooling zone is the liquid stream comprising the bottom dissolved gas and the top hydrogen / light hydrocarbon stream. The hydrogen / light hydrocarbon stream optionally passes through a second hydrogen sulfide removal zone which generally uses an amine adsorbent for removal of hydrogen sulfide. The eluate recovered from the optional H ₂ S removal zone will optionally pass through a second hydrotreatment zone, such as the hydrocracking zone mentioned below.

The liquid stream containing the dissolved gas passes through the separation zone. Conventional separations generally used distillation. Other fractions and light products selected from the bottom liquid, one or more by-products or intermediates and mixtures thereof are recovered. Other fractions, such as bottom liquid and / or one or more by-products or intermediates, will pass through a second hydrotreatment zone, such as a hydrocracking zone. Under hydrocracking conditions the bottom liquid and / or one or more by-products or intermediates are contacted with the hydrocracking catalyst. The hydrocracking zone eluate is recovered again. The hydrogenation zone eluate again passes through a denitrification and desulfurization zone, one aspect of the first hydrotreatment zone.

The use of the two reaction zones in the present invention can vary. That is, the first and second hydroprocessing or reaction zones may be hydroprocessing zones or denitrification and desulfurization zones, respectively. In one embodiment of the present invention, the lower zone that is first contacted with the fresh feed is the denitrogen and desulfurization zone. The top feed is the hydrocracking zone. The other area is also reversed. Optionally each zone may be a hydrocracking zone or each denitrification and desulfurization zone. Each may also be combined or mixed with the hydrocracking zone and with the denitrogen and desulfurization zone.

B. Advantages of the Method

The present invention provides a single reaction loop. This single reaction loop method is inexpensive compared to the use of multiple reaction loops. On the other hand, the single reaction loop of the present invention retains the advantages of the catalyst applied for pre-treated feeds of high reaction rates or multiple reaction loop systems. The present invention takes place in a series of reactors or in the top layer of the reactor or in the reactor bed or in the upper reaction zone while the general feed process is carried out in subsequent bottom reaction zones.

Another advantage of a series of arrangements over an equilibrium reactor arrangement for initial and high conversion stages is the minimization of gas circulation to reduce investment and operator costs. Capital is reduced by using less equipment and pipes. The operator is lowered because of less compression on the recycle gas. (a) the high conversion eluate from the top reaction zone serves as a partial endotherm, thereby reducing the immersion requirements for the initial process in the subsequent zone, and (b) the use of the high conversion eluate from the top zone. Unconcentrated hydrogen serves as a partial source of hydrogen in the initial process in the subsequent zones, and (c) high conversion eluate from the top reaction zone improves the distribution of hydrogen and fresh feed for reaction to the catalysts in the subsequent zones. Gas circulation is reduced compared to the initial process in an equilibrium reactor or separate loop in the same loop. Thus, the advantage of using a single loop is that it reduces the cost of investment and the operator, one for the initial process and the other for not duplicated equipment of two separate loops that are similar for high conversion stages.

The advantages of the process of separating the pretreated hydrocarbons from the fresh feed in the upper reaction zone or top layer are: (a) the top layer catalyst is not contaminated with feed impurities, and (b) the reaction rates in the top layer are NH ₃ , and H. unimpeded by the large amount of hydrogenation by-products, such as the ₂ S, (c) hydrogen partial pressure to maximize the finishing process.

The invention may also provide an advantage in the bottom reaction zone that reduces the pulsation tendency in certain aspects of the remaining processes.

C. Feeds and Products

Suitable feeds and preferred products obtained for the use of the present invention are conventional or known hydrocracking / hydrogenation feeds and products. Feeds and preferred products of the process are described in U.S. Patents 5,277,793; 5,232,577; 5,232,577; 5,073,530; 5,073,530; No. 4,430,203; And 4,404,088, which are incorporated herein by reference. In a preferred embodiment, the hydrocarbon feed is selected from residues, vacuum gas oils, middle distillates and mixtures thereof.

D. Reaction Conditions and Catalyst

Suitable hydrocracking and hydroprocessing catalysts and reaction conditions include conventional or known catalysts and reaction conditions. Suitable catalysts and reaction conditions for the process are described in U.S. Patents 5,277,793; 5,232,577; 5,232,577; 5,073,530; 5,073,530; No. 4,430,203; And 4,404,088, which are incorporated herein by reference. If the reaction zone is a denitrogen and / or desulfurization zone, the contact occurs under denitrogen and / or desulfurization conditions. If the reaction zone is a hydrocracking zone, the contact takes place under hydrocracking conditions.

If the process described above is used in hydrotreating the feed to remove sulfur and nitrogen impurities, the following reaction conditions will generally be used: reaction temperatures 400 to 900 ° F .; Pressure 500-5000 psig; LHSV 0.5 to 20; And total hydrogen consumption is between 300 and 2000 scf per barrel of liquid hydrocarbon feed. Hydrotreating catalysts for beds generally include compositions of Group VI metals and compounds thereof; And Group VIII metals or compounds thereof supported on a porous refractory base such as alumina. Examples of hydrotreating catalysts include alumina, nickel sulfide, tungsten-nickel sulfide, cobalt molybdate and nickel molybdate supported on cobalt-molybdenum.

Likewise, when the process is used in hydrocracking feeds, the following operating conditions will generally be preferred: reaction temperatures 400 to 950 ° F .; Pressure 500-5000 psig; LHSV 0.1-15; And total hydrogen consumption is between 500 and 2500 scf per barrel of liquid hydrocarbon feed. Hydrocracking catalysts for beds are generally oxides or sulfides supported on Group VI metals, Group VIII metals or porous refractory bases such as silica or alumina. Examples of hydrocracking catalysts are oxides or sulfides of Mo, W, V and Cr supported on substrates such as Mo, W, V and Cr.

In general, when the reaction zone is a denitrogen and / or desulfurization zone, the catalyst is any catalyst that will catalyze denitrogen and / or desulfurization under denitrogen and / or desulfurization conditions. If the reaction zone is a hydrocracking zone, the catalyst is any catalyst that will catalyze hydrocracking under hydrocracking conditions.

Claims (19)

(a) a hydrocarbon feed selected from the residue, vacuum gas oil, middle distillate and mixtures thereof passes through the denitrification and desulfurization zone; A temperature of about 400 to about 900 ° F .; A pressure of about 500 to about 5000 psig; A flow rate of about 0.5 to about 20 LHSV; And contacting said hydrocarbon feed with a denitrification and desulfurization catalyst at a total hydrogen consumption of about 300 to 2000 scf per barrel of liquid hydrocarbon feed; Recovering the eluate of the denitrification and desulfurization zones from them; (b) passing the eluate of the denitrification and desulfurization zones through a purification / cooling zone to remove ammonia and hydrogen sulfide and cooling the liquid stream and hydrogen / light hydrocarbon stream containing dissolved gases from the purification / cooling zone, Recover; (c) passing said liquid stream containing dissolved gas through a separation zone and recovering light product, liquid bottoms, and at least one by-product intermediate therefrom; (d) passing the liquid bottoms and the by-product intermediate and the hydrogen / light hydrocarbon stream of step (b) through a hydrocracking zone; A temperature of about 400 to about 950 ° F .; A pressure of about 500 to about 5000 psig; A flow rate of about 0.1 to about 15 LHSV; And contacting the liquid bottoms and the by-product intermediate with a hydrocracking catalyst at a total hydrogen consumption of about 500 to 2500 scf per barrel of liquid hydrocarbon feed; Recovering the eluate in the hydrocracking zone therefrom; (e) reverse feed hydrotreatment of the hydrocarbon feed to obtain high conversion, selective hydrotreatment and product selectivity in a hydroprocess reactor system, comprising passing the eluate of the hydrocracking zone through the denitrification and desulfurization zone. How to. Hydroprocessing reactors that include performing higher conversions in a single reaction loop or further processing in a lead reactor in a series of reaction loops or in the upper reaction zone of the reactor and subsequent general feed processes in subsequent reaction zones. Reverse step method to achieve high conversion, selective hydrotreatment and product selectivity in the system. 3. The method of claim 2, further comprising feeding supplemental hydrogen to the upper zone or subsequent reaction zone. The process of claim 2, further comprising: (a) recovering subsequent eluate in the reaction zone and passing the eluate through a cooling zone; (b) recovering from the cooling zone a liquid hydrocarbon stream containing hydrogen / light hydrocarbon stream and dissolved gas; (c) passing the hydrogen / light hydrocarbon stream through the upper reaction zone; (d) passing the liquid stream containing dissolved gas through a separation zone. The process of claim 3, wherein the general feed is selected from residue, vacuum gas oil, middle distillate and mixtures thereof and the hydrogen / light hydrocarbon stream of step (b) is subjected to the lead reactor or the top reaction of step (c). And passing the hydrogen sulfide removal zone before passing through the zone. 5. The process of claim 4, wherein the reaction zone subsequently comprises a hydrocracking zone and comprises a hydrocracking catalyst, the hydrocracking zone having a temperature of about 400 to about 950 ° F; A pressure of about 500 to about 5000 psig; A flow rate of about 0.1 to about 15 LHSV; And a total hydrogen consumption of about 500 to 2500 scf per barrel of liquid hydrocarbon feed. 6. The process of claim 5 wherein the reaction zone is subsequent to a denitrogen and desulfurization zone and the process comprises a temperature of about 400 to about 900 [deg.] F .; A pressure of about 500 to about 5000 psig; A flow rate of about 0.5 to about 20 LHSV; And denitrification and desulfurization catalysts in the denitrification and desulfurization zone at a total hydrogen consumption of about 300 to 2000 scf per barrel of liquid hydrocarbon feed with a general feed selected from residues, vacuum oils, intermediate distillates and mixtures thereof. And further comprising contacting and further recovering the eluate of the denitrification and desulfurization zones. The process of claim 4, wherein the reaction zone is subsequently hydrocracked and the process comprises a temperature of about 400 to about 950 ° F .; A pressure of about 500 to about 5000 psig; A flow rate of about 0.1 to about 15 LHSV; And contacting the hydrocracking catalyst in the hydrocracking zone with a general feed selected from residue, vacuum gas oil, middle distillate and mixtures thereof at a total hydrogen consumption of about 500 to 2500 scf per barrel of liquid hydrocarbon feed. How to include. 8. The method of claim 7, wherein the top reaction zone or lead reactor is a hydrocracking zone and the process comprises a temperature of about 400 to about 950 ° F; A pressure of about 500 to about 5000 psig; A flow rate of about 0.1 to about 15 LHSV; And contacting the hydrocracking catalyst in the hydrocracking zone with at least a portion of the eluate of the denitrification and desulfurization zone at a total hydrogen consumption of about 500 to 2500 scf per barrel of liquid hydrocarbon feed. 5. The process of claim 4 wherein the top reaction zone or lead reactor is a denitrogen and desulfurization zone. 10. The method of claim 9, wherein (a) the eluate of the denitrification and desulfurization zones is passed through a purification / cooling zone for removal of ammonia and hydrogen sulfide and the liquid stream and dissolved hydrogen / light hydrocarbon stream containing dissolved gases are purified. Cooling and withdrawing in the cooling zone; (b) passing said liquid stream containing dissolved gas through a separation zone and recovering light product, liquid bottoms, and at least one by-product intermediate from them; (c) passing said liquid bottoms and said by-product intermediate and said hydrogen / light hydrocarbon stream of step (b) through said top reaction zone. (a) passing a hydrocarbon feed through a second hydrotreatment zone and contacting the hydrocarbon feed with a second hydrotreatment catalyst under hydrotreatment conditions to recover an eluate from the second hydrotreatment zone; (b) passing the hydrotreated product through a vapor-liquid separation zone to recover other fractions selected from light product and liquid bottoms, one or more intermediates and mixtures thereof; (c) passing said other fractions through a first hydrotreatment zone and contacting said hydrocarbon feed with a first hydrotreatment catalyst under hydrotreatment conditions to recover an eluate from the first hydrotreatment zone; and (d) passing the eluate of said first hydroprocessing zone through said second hydroprocessing zone. 13. The method of claim 12 further comprising supplying supplemental hydrogen to said second hydroprocessing zone. 13. The process of claim 12, further comprising: (a) passing the eluate of the second hydroprocessing zone through the ammonia and hydrogen sulfide removal and cooling zone; (b) recovering a liquid hydrocarbon stream containing hydrogen / light hydrocarbon stream and dissolved gas in the ammonia and hydrogen sulfide removal and cooling zone; (c) passing the hydrogen / light hydrocarbon stream through the hydrotreatment zone; (d) passing said liquid hydrocarbon stream containing dissolved gas through said vapor-liquid zone. 15. The process of claim 14, wherein the hydrocarbon feed is selected from residues, vacuum gas oils, mid-distillates and mixtures thereof. 13. The method of claim 12, wherein said second hydroprocessing zone is at a temperature of about 400 to about 900 [deg.] F .; A pressure of about 500 to about 5000 psig; A flow rate of about 0.5 to about 20 LHSV; And a denitrification and desulfurization zone having a total hydrogen consumption of about 300 to 2000 scf per barrel of liquid hydrocarbon feed and the second hydrotreating catalyst is a denitrogen and desulfurization catalyst. 17. The method of claim 16, wherein said second hydroprocessing zone is a hydrocracking zone. 13. The method of claim 12, wherein said first hydroprocessing zone is at a temperature of about 400 to about 950 [deg.] F .; A pressure of about 500 to about 5000 psig; A flow rate of about 0.1 to about 15 LHSV; And a hydrocracking zone having a total hydrogen consumption of about 500 to 2500 scf per barrel of liquid hydrocarbon feed, wherein the first hydrotreating catalyst comprises a hydrocracking catalyst. 13. The process according to claim 12, wherein the first hydroprocessing zone is a denitrification zone and a desulfurization zone.