JPH0653875B2 - Multi-step contacting process for high conversion of heavy hydrocarbon liquid feedstocks - Google Patents

Description

Description: FIELD OF THE INVENTION This invention relates to a method for catalytically converting heavy hydrocarbon liquid feedstocks at high rates using a multi-stage catalytic reactor in which the flow arrays are connected in series. Is. Especially at least about 25V
% Multi-stage hydroconversion process for heavy petroleum feedstocks boiling above 524 ° C (975 ° F) with a vacuum bottoms material fraction recirculated to the final stage catalytic reactor to improve the hydrogen conversion rate of the feedstock. It relates to producing high and low boiling hydrocarbon liquids and gaseous products.

PRIOR ART AND PROBLEMS Hydroconversion of hydrocarbon feedstocks in single flow operation in a single contact reactor to produce low boiling hydrocarbon liquids and gases is usually limited to about 75V% conversion. Nothing more than. To convert petroleum residues at a high rate, the heavy resid fraction was recycled to the reactor and the resid fraction was recycled to the first stage catalytic reactor in a two stage reactor system. However, in this kind of two-stage catalytic operation of hydrocarbon liquid feedstocks, the conversion in the first-stage reactor generally does not exceed about 60 V%,
The addition of the heavy recycle liquid fraction to the first stage reactor, in combination with the total residence time of the bottoms fraction in the reactor conditions, results in relatively low bottoms concentration changes occurring therein. Not very effective.

Catalytic hydrogenation and conversion of petroleum residues in a single stage boiling bed catalytic reactor in which a vacuum bottoms fraction is recycled to the reactor is well known and is described in U.S. Pat.Nos. 2,987,465 and 34120.
No. 10 is disclosed. U.S. Pat. No. 3,184,402 discloses a two-stage catalytic hydrocracking process in which an intermediate fractionation and some distillation bottoms fraction recycle to either the first or second catalytic cracking zones. Also, U.S. Pat. No. 3,775,293 discloses a two-stage desulfurization process in which some heavy oil fractions boiling above diesel fuel oil are recycled to a second stage fixed bed reactor. However, these processes recycle relatively low-boiling materials, but provide high conversions of high-boiling heavy hydrocarbon liquid feedstocks such as petroleum residues that normally boil above about 426 ° C (800 ° F). In order to do so, an improved process is needed. Unexpectedly, the effect of recycling the heavy liquid fraction on the overall conversion of the heavy hydrocarbon feedstock is to transfer the heavy liquid fraction to the final stage reactor of a multi-stage catalytic reactor system. It is even more advantageous when recycled.

SUMMARY OF THE INVENTION The present invention provides a high rate of low hydrogen conversion of heavy hydrocarbon liquid feedstocks containing at least about 25 V% material that normally boil above 524 ° C (975 ° F). A multi-step contacting process for producing boiling hydrocarbon liquids and gaseous products is provided.
In this method, a liquid feed material is catalytically reacted with hydrogen in a liquid phase in a multi-stage catalytic reactor system at high temperature and high pressure to obtain a temperature of about 426 ° C.
A heavy vacuum bottoms fraction having a nominal cut-point temperature of (800 ° F) or higher, preferably about 454 ° C (850 ° F) or higher, is recycled to the final stage boiling catalyst bed reactor of the multi-stage reactor system. , Improves the conversion of feedstocks, especially 524 ° C ⁺ (975 ° F ⁺ ) material fractions, thereby increasing the yield of C ₄ -524 ° C (975 ° F) liquid products.

More particularly, the process of the present invention feeds a heavy hydrocarbon liquid feedstock and hydrogen to a first stage catalytic reactor containing a particulate catalyst, the reactor at a temperature of 415-455 ° C (780-850 ° F), 7
Hydrogen partial pressure of 0.3 to 210.9 kg / cm ² (1000 to 3000 psig) and total space velocity of 0.20 to 2.0 V _f / hour / V _r (fresh feed capacity vs. time vs. reactor capacity) are maintained and supplied. Partial hydrogen conversion of the feedstock produces effluent; 415-455 ° C (780-850
Final stage boiling bed contact reaction maintained at a temperature of ℃ (F), a hydrogen partial pressure of 70.3 to 210.9 kg / cm ² (1000 to 3000 psig), and a total space velocity of 0.20 to 2.0 V _f / hour / V _r The partially hydrogen-converted effluent through all subsequent catalytic reactors, including reactors, and further hydrogen-converting the material to produce hydrocarbon gas and low boiling liquid fractions; said hydrocarbon gas and liquid The fraction is removed from the final stage reactor, the hydrocarbon gas is separated from the liquid fraction and the liquid fraction is withdrawn; the fraction is distilled to obtain a normal boiling range of 204.4-399 ° C (400-750 ° F). ),
Medium boiling hydrocarbon liquid product from 399 to 524 ° C (750 to 975 ° F) and usually with a cut point temperature of about 524 ° C (975 ° F)
Producing the above vacuum bottoms material; Recycling at least a portion of said vacuum bottoms material to said final stage boiling bed catalytic reactor to produce said intermediate boiling hydrocarbon liquid product with increased yield. Consists of.

The present invention is effective in the hydroconversion of bi-smen and raw shale oil from petroleum residue tar sands. This method is continuous 3
Individual catalytic reactors can be used, using two boiling bed catalytic reactors connected in series with recycle of heavy vacuum bottoms cut to the second stage reactor Is preferred. The process can use any type of catalytic reactor system, but usually a boiling bed catalytic reactor is usually preferred for liquid feedstocks containing some solid particles and / or metal compounds.

The advantages of the present invention, in which at least a portion of the heavy hydrocarbon liquid fraction is recycled to the second or final stage catalytic reactor, includes higher hydrogen conversion of the feedstock to increase the hydrocarbon distillate partial product yield. To increase.

DETAILED DESCRIPTION OF THE INVENTION In a preferred embodiment of the present invention, a heavy hydrocarbon liquid feedstock such as petroleum residue is pressurized, heated and co-processed with hydrogen gas.
It is introduced into the first stage catalytic reactor of the staged catalytic reactor system. The first stage reactor is either a fixed bed or a bubbling bed catalytic reactor and is particularly preferred for feedstocks containing total metal content of about 300 ppm or greater, which is usually predominantly vanadium and nickel compounds. A boiling bed reactor can be used. The state of the first stage reactor sphere is 415
~ 455 ℃ (780 ~ 850 ℃) temperature, 70.3 ~ 210.9kg / cm ² (10
Maintaining the total space velocity of the hydrogen partial pressure and 0.2~2.0V _f / hr / V _r of 00~3000psig), to achieve a partial contact hydroconversion of the feedstock. Preferred reaction conditions are 421-449 ° C (790-840 ° F)
Temperature, 84.3 to 196.9 kg / cm ² (1200 to 2800 psig) hydrogen partial pressure and 0.25 to 1.8 V _f / hr / V _r total space velocity.

The gas obtained from the first stage reactor and the partially converted liquid material are passed through a second stage boiling bed catalytic reactor with additional hydrogen to carry out further hydroconversion reactions. The second stage reactor can be maintained at about the same conditions as in the first stage reactor by treating the feedstock and converting it at the desired rate. If the feedstock contains more than about 300 ppm of all metals such as vanadium and nickel, a demetallization type catalyst, i.e., a cheap catalytic material that can preferentially remove nickel and vanadium on sulfur, will cost less. It is preferable to use it in a one-step boiling bed reactor, and a hydroconversion or desulfurization type catalyst having high activity is used in the second stage.
Used in a stepped bed reactor. The demetallized catalyst can be a naturally occurring bauxite or aluminum oxide material with minor amounts of other metal oxides such as iron or molybdenum as known to those skilled in the art. The hydroconversion or desulfurization type catalyst is selected from the group consisting of cadmium, chromium, cobalt, iron, molybdenum, nickel, tin, tungsten and mixtures thereof supported on a support material selected from the group of alumina, silica, and combinations thereof. Activated metal oxide.

The effluent from the second stage reactor is phase separated and the resulting liquid portion is passed to the distillation stage at low pressure. The resulting vacuum bottoms fraction is recycled to the second stage boiling bed catalytic reactor,
The residual oil concentration in the reactor is now much lower than in the first stage, so that the effect of the heavy recycle liquor on the feed conversion is maximized.

According to the present invention, as shown in FIG. 1, there is no effect of recirculating the vacuum bottoms fraction due to conversion of the heavy hydrocarbon feedstock at a conversion level of about 60% or less, but conversion of about 60 V% or more. The effect of vacuum bottoms recycle with% conversion is even more beneficial when the recycle fraction is fed to the final stage reactor of a multi-stage catalytic reactor system, as shown in FIG.

The effect of% conversion of heavy hydrocarbon feedstock produced by recirculating vacuum bottoms material to a single stage reactor is shown in Figure 1, where% conversion using vacuum bottoms recycle to single stage reactor is shown. The results were plotted against a single stage conversion achieved without any such recycling. As can be seen from the graph, in line A, at conversions below about 60 V%, the effect of heavy liquid recycle to the reactor by% conversion is zero because the reason is relatively low occurring in the reactor. This is because the residual oil concentration change cannot offset the reduced residence time of the residual oil under the reactor conditions. However, as the% conversion increases, the concentration of the residual oil fraction (typically 524 ° C ⁺ (975 ° F ⁺ )) in the reactor liquor decreases, for example by increasing the severity of the reaction. Therefore, the change in the concentration of the residual oil fraction in the reactor caused by the addition of the vacuum bottoms fraction to the reactor is greater than that present for low conversion conditions. Even at lower residual oil residence times than single flow operation, this recycle arrangement will increase the% conversion of the feedstock. This result is shown by the data obtained by drawing the line B in FIG.

In the two-stage catalytic reactor operation, the conversion of the first-stage reactor is usually about 60 V% or less. Therefore, recirculation of the heavy liquid to the first stage reactor is effective in improving the residual oil conversion rate of only about 60% or more as shown by the line B in FIG. Is. However, as mentioned above, the conversion is achieved by recirculating the heavy liquid or resid fraction to the second stage instead of the first stage reactor, as shown in Figure 2 line C. We have found that it can be further improved. In both the first stage and the second stage, even if the residual oil recirculation to the first stage reactor results in a higher residual oil concentration, this increase in conversion occurs but the residual oil is converted to the second stage reaction. When recycled to the reactor, the first reactor benefits from the higher residual oil concentration therein. The overall conversion rate is still 1st
Only when compared to the recycle to the stage is it higher with the recycle of the residual fraction to the second stage, because the increase in the residual oil residence time is more than the compensation for the reduced concentration. Because you get Thus, when the bottoms fraction is recycled to the second or final stage reactor, the net result is a higher level of conversion than when it is recycled to the first stage reactor.

As an explanation for this recycle relationship, the% hydroconversion of the feed heavy liquid fraction is affected primarily by three factors. That is, the reactor temperature, the concentration of the heavy liquid or the residual oil fraction in the reactor, and the residual oil residence time in the reactor. Increasing the level of any of these factors will increase the conversion of the resid as the rate changes. When the concentrated portion of the unconverted heavy liquid is recycled to the catalytic reactor, it increases the concentration of this resid material in the reactor. However, the residence time for residual oil is actually reduced, and if the residence time is defined as the volumetric cut of the residual oil over the total reactor liquid feed time, the reactor volume is the total liquid volumetric feed to the reactor. Is broken by. This reduction in bottoms residence time results in more bottoms feed per unit time through the same reactor volume.

To show these changes in the residual oil residence time, the arrangement of the three streams for the two-stage catalytic reactor hydroconversion operation is shown in Figure 3 and the three types of operation are shown. Use a consistent basis for each placement. That is, the two reactors have the same temperature and the same capacity, and the new feed rate to the reactor system is the same for each. For the two recirculation arrangements B and C, the residual oil residence times are both lower than for arrangement A in the single flow operation.

A preferred embodiment of the present invention is shown in FIG. As shown in FIG. 4, a heavy petroleum feedstock, such as Kuwait vacuum bottoms or saffanier vacuum bottoms, is fed at 10, pressurized by a pump 12 and passed through a preheater 14 at least about 260 ° C. (500 Heat the feed up to ° F) but not to a temperature high enough to cause feedstream coking in the preheater. The heated feed stream 15 is fed to the first stage counter-current boiling bed catalytic reactor 20. Supply heated hydrogen at 16.
Lead to reactor 20. Reactor 20 includes an inlet flow distributor and a catalyst-supporting grid 21 so that feed liquid and gas pass uniformly upwardly through reactor 20 and have a fixed height of at least about 10% and usually less than about 50%. Spread the catalyst bed over and place the catalyst in a liquid in random motion. This reactor is typically that described in U.S. Pat. No. Re. 25,770, in which the liquid phase reaction occurs in the presence of a reaction gas and a particulate catalyst which causes the catalyst bed to expand.

The catalyst particles in bed 22 typically have a relatively narrow diameter range for uniform bed expansion under controlled upper liquid and gas flow conditions. A useful catalyst particle size range is 6-100 mesh (US sieve series), but the catalyst has a diameter of about 0.0254-0.254c.
Particles with a diameter of 6 to 50 mesh containing extrudates of m (0.010 to 0.100 inches) are preferred. In the reactor, catalyst particle density, liquid upflow, and countercurrent liquid and hydrogen gas rise are important factors in catalyst bed expansion and operation. By adjusting the catalyst particle size and density and the countercurrent liquid and gas velocities, and by taking into account the liquid particle size at the reactor operating conditions, the catalyst bed 22 expands to the desired degree,
It provides an upper level or interface of liquid as indicated at 22a.

The hydroconversion reaction of bed 22 is greatly facilitated by the use of active catalyst. The catalyst used is a typical hydrogenation catalyst containing an activated metal oxide supported on a support material of alumina, silica, and combinations thereof. Appropriate inlet connection device 2 with fresh catalyst periodically at a ratio of 45.4 to 908 g (0.10 to 2.01b) of catalyst / 159 petroleum feedstock (1 barrel)
Add directly to reactor 20 through 5 and withdraw spent catalyst through a suitable stripper 26 to maintain the desired catalyst residue and activity in the reactor. For hydrocarbon feedstocks containing greater than about 300 ppm total vanadium and nickel, it is necessary to use a demetallization type catalyst in the first stage reactor.

Recirculating the reactor liquid from above the solid interface 22a to below the flow distributor 21 maintains sufficient backflow liquid to maintain the catalyst in the desired expanded random motion in the liquid and facilitate effective reaction. Usually needed to establish. Such liquid recirculation is preferably accomplished by the use of a central downcomer conduit 18, the tube 18 extending to a recirculation pump 19 located below the flow distributor 21 for the catalyst bed 2
Ensure a positive and controlled backflow of liquid through 2. Recirculating the reactor liquid through the inner conduit 18 has some mechanical advantages and tends to reduce the number of external high pressure connecting tubes required for the hydrogenation reactor, but at the expense of the upper flow through the catalyst bed. Liquid recirculation to can be established by a recirculation conduit and a pump external to the reactor. In a boiling bed reactor system,
The space 23 is above the liquid level 23a.

The possibility of operating a boiling catalyst bed reactor system to ensure good contact and uniform (isothermal) temperature therein to achieve the desired hydroconversion results from the levitation effect of countercurrent liquids and gases. In addition to relying on the random motion of catalyst particles in a liquid environment, proper reaction conditions are also needed. Inadequate reaction conditions are used to achieve inadequate hydroconversion, which results in inhomogeneous liquid stream distribution and usually excessive coke deposits on the catalyst.

For hydroconversion of petroleum feedstocks using the present invention, the operating conditions required for reactor 20 are 415-455 ° C (780-850 ° F) temperature range, 70.3-210.9 kg / cm ² (1000-3000 psig). there the hydrogen partial pressure, and 0.2~2.0V _f / hr / V _r (fresh feed capacity vs. time vs. reactor volume) in the range of the total space velocity. Preferred reactor conditions are 421-449 ° C (790-840 ° F) temperature, 8
Hydrogen partial pressure of 4.36 to 196.84 kg / cm ² (1200 to 2800 psig) and total space velocity of 0.25 to 1.8 V _f / hr / V _r . Achieved feed hydrogen conversions of at least about 6 in single flow operation.
It is 0V%.

From the first stage reactor 20, an overhead stream containing a gas and liquid distillate mixture is withdrawn at 27 and is passed to the lower end of a second stage reactor 30 containing a boiling bed 32 of particulate catalyst. The catalyst 32 is usually the same particle size as that used in the reactor 20, but may be slightly larger and preferably has an effective diameter of 0.076 to 0.1778 cm (0.030 to 0.070 inch). The operation of this second stage ebullated bed reactor 30 is quite similar to that of the reactor 20, with the reactor liquid recirculating upward through the downcomer conduit 34 and pump 35 and then through the flow distributor 31. Ensure uniform, controlled expansion and boiling of the catalyst bed 32. Suitable reaction conditions used in the reactor 30 are temperature 415 to 455 ° C (780 to 850 ° F), hydrogen partial pressure 70.3 to 210.9 kg / cm ² (1000 to 3000 psig), and total space velocity 0.2 to 2.0 _Vf / Hour / V _r . Preferred reaction conditions are a temperature of 421 to 449 ° C (790 to 840 ° F) and a hydrogen partial pressure of 84.36 to 196.8.
4kg / cm ² (1200-2800psig), and total space velocity 0.25-
It is a 1.8V _f / hr / V _r. A new catalyst is added, and the catalyst drawn from the reactor 30 is used as necessary to make the reactor 2
Maintain the desired catalytic activity at the same time as zero.

An effluent stream 39 containing gas and low boiling hydrocarbon liquid fraction is withdrawn from the reactor 30 and passed through a high pressure phase separator 40.
The resulting gas fraction 41 contains mainly hydrogen recovered in the gas purification stage 42. Vent gas containing mainly H ₂ , CO ₂ , H ₂ S, light hydrocarbon gas and water is removed at 43. The hydrogen recovered at 44 is normally recycled through the conduit 45 by the compressor 44a, reheated at the heater 46 if necessary, and then at 45a with the make-up hydrogen at the bottom of the reactor 20 at 45a. Be led to.
In addition, a part of the hydrogen flow 45 is reheated by the heater 47 as needed, and is introduced into the reactor 30 together with the outflow flow 27.

The remaining liquid fraction 48 from the separator 40 is about 14.06 kg / cm ²
The pressure is reduced to 49 (200 psig) or less and passed through a fractionation stage 50 from which a low pressure hydrocarbon vapor stream 51 is withdrawn. This vapor stream is phase separated at 52 and the low pressure product gas 5
3, a liquid stream 54 that provides reflux liquid to the fractionator 50, and a naphtha product stream 55. The middle boiling range distilled liquid product stream is withdrawn at 56 and the heavy fuel oil liquid stream is withdrawn at 58.

From the fractionator 50, a heavy bottoms oil stream 58, which typically has a boiling temperature range of 343 to 524 ° C. (650 to 975 ° F.), is reheated with a heater 59 as needed and passed through a vacuum distillation stage 60. The vacuum gas oil product stream is drawn at 62 and the vacuum bottoms stream is drawn at 64. A portion 65 of the vacuum bottoms material having a nominal boiling point or cut point of about 426.7 ° C. (800 ° F.) or higher, preferably about 454.4 ° C. (850 ° F.) or higher is pressurized at 66 and, if necessary, to the heater 67. And reheat to reactor 30 for further hydrogen conversion reactions to achieve a conversion of 75-95 V% feed to low boiling hydrocarbon materials. Depending on the product and% conversion desired from this process, at least about 50 V% and preferably all of the vacuum bottoms material is recycled at 64 to reactor 30. The volume ratio of recycled 524 ° C ⁺ (975 ° F ⁺ ) material to fresh feed should be in the range of about 0.2 to 1.5. Heavy vacuum pitch material is withdrawn at 68 for further processing or optional use.

Hereinafter, the present invention will be described based on examples.

Example 1 The benefits to vacuum bottoms full contact two stage conversion and yield provided by the heavy liquid recycle arrangement of the present invention are summarized in Table 1 below. In this example, the vacuum bottoms fraction boiling above 426.7 ° C. (800 ° F.) is recycled to the first stage reactor of the two reactor system for Case 1 and the second for Case 2. Recycle to stage reactor.

As can be seen from the results in Table 1, under the same operating conditions, the feed conversion obtained by recirculating the vacuum bottoms fraction to the second stage reactor is the same as the recycle to the first stage reactor. About 6% higher than. A comparable improvement is shown for distillate yield, but the overall yield of C ₄ -524 ° C. (975 ° F.) material is also about 5.9 V% greater using the present invention.

Example 2 The heavy liquid recycle arrangement of the present invention can advantageously be extended to a three-stage catalytic reactor, using a three-stage catalytic reaction process operating at the same reaction conditions at each stage. Can be operated with the same heavy petroleum feedstock as. Vacuum Bottoms Recycled material is the first of the three-stage reactor system
Add to either stage reactor, second stage reactor, or third stage reactor. The results of comparative conversions achieved by using the recycle of vacuum bottoms cut to each stage reactor are shown in Table 2 below.

All other operating conditions are the same for all three cases.

From the above results, it can be seen that a very high conversion rate of 524 ° C ⁺ (975 ° F ⁺ ) substance in the feedstock has been achieved, and the conventional single-stage reactor or second-stage catalytic reactor According to the present invention using the recycle of vacuum bottoms cut to the third stage reactor rather than the recycle to 204.4-534 ° C.
It can be seen that it increases the yield of products in the boiling range (400-975 ° F).

[Brief description of drawings]

 1 and 2 show the vacuum bottoms fraction as a first or
The comparison result, which is recirculated to the final stage catalytic reactor, is operated as a single flow.
% Hydrogen conversion of feedstock to results obtained from
It is a graph. FIG. 3 is a schematic view of three catalytic hydroconversion devices,
Single-flow two-stage reactor with similar residence time for residual oil fraction
Floor operation, heavy liquid recirculation to the first stage reactor, and
How affected is the heavy liquid recirculation to the two-stage reactor
Indicates whether or not FIG. 4 is a vacuum bottoms for the final stage reactor according to the present invention.
For heavy hydrocarbon liquid feedstocks with fraction recycle
FIG. 3 is a schematic view of the two-step catalytic hydroconversion method of FIG. In Fig. 1, ○ is 4770 (30 barrels) / day □ is 397.5 (2.5 barrels) / day △ is 159 (1 barres) / day Residual oil supply = 7 API, sulfur 5.2W%In Figure 2, line A = single flow operation line B = vacuum bottoms recycle to single stage reactor line C = vacuum bottoms recycle to second reactor in a two stage system
ring. In Figure 3, the total reactor temperature is 440.5 ° C (825 ° F) and the total reactor capacity is 2.83m.³(100ft³) Total flow rate is 2.83 × 10^-2m³(1ft³) / Hour Fig. 3A shows two steps, single flow operationFigure 3B shows heavy liquid recycle to the two-stage, first-stage reactor.
ring.FIG. 3C shows heavy liquid recycle to the two stage, second stage reactor.1 ... 1st reactor, 2 ... 2nd reactor 3 ... Separation, fractional distillation, vacuum distillation apparatus 12 ... Pump, 14 ... Preheater 18,34 ... Central descending conduit 19, 35 ... Re Circulation pump 20 …… First stage backflow boiling bed contact reactor 30 …… Second stage boiling bed reactor 21,31 …… Flow distributor 22,32 …… Catalyst bed 25 …… Inlet connection device 26 …… Extractor 40 ... High-pressure phase separator, 42 ... Gas purification stage 44a ... Compressor, 46, 47, 59, 67 ...
Heater 50 …… Separator, 60 …… Vacuum distillation stage

Continuation of the front page (56) References JP-A-58-32694 (JP, A) JP-A-57-209993 (JP, A) JP-A-53-77204 (JP, A) JP-A-47-2230 (JP , A) JP-B 52-45321 (JP, B1) JP-B 49-34165 (JP, B1) JP-B 45-12009 (JP, B1)

Claims (16)

[Claims] 1. A first stage catalytic reactor containing (a) a granular catalyst is fed with a hydrocarbon feedstock containing at least 25 V% of a substance boiling above 524 ° C. (975 ° F.) with hydrogen. The reactor is heated to 415-455 ° C (780-
850 ° F), 70.3-210.9kg / cm ² (100
Hydrogen partial pressure of 0-3000 psig) and 0.20-2.0 V _f
/ Maintaining the total space velocity hr / _{V r,} the feed partially generates hydroconversion flowing material; (b) 415~455 temperature ° C. (seven hundred and eighty to eight hundred and fifty degrees F),
70.3-210.9kg / cm ² (1000-3000psig)
Hydrogen partial pressure, and was the partially hydrogenated converted to 0.20～2.0V f _/ hr / in V _r of all including the last stage boiling-bed catalytic reactor maintained at a total space velocity subsequent stage catalytic reactor Passing the effluent directly, and further hydrogen-converting this material to produce a hydrocarbon gas and a low boiling liquid fraction; (c) removing said hydrocarbon gas and liquid fraction from said final stage reactor, said carbonization Hydrogen gas is separated from the liquid fraction and the liquid fraction is withdrawn; (d) The liquid fraction is distilled to obtain a temperature of 204.4 to 426.7 ° C (400
To a medium boiling point hydrocarbon liquid product having a normal boiling range of ~ 800 ° F) and a vacuum bottoms material having a nominal boiling point of about 426.7 ° C (800 ° F) or higher; and (e) said vacuum bottoms material At least one part was recycled directly to the final stage boiling bed catalytic reactor to achieve a conversion of at least about 75 V% of the 524 ° C. ⁺ (975 ° F ⁺ ) cut to low boiling materials, yielding Multi-step contact for high conversion of heavy hydrocarbon liquid feedstock to increase the conversion rate and increase the production of low-boiling hydrocarbon liquids and gases to produce increased said medium boiling hydrocarbon liquid product Method. 2. The method of claim 1 wherein said first stage reactor comprises a fixed bed of particulate catalyst. 3. The method of claim 1 wherein said first stage reactor comprises a boiled bed of particulate hydrogenation catalyst. 4. The first stage reaction condition is 421 to 449 ° C.
Temperature (790-840 ° F), 84.3-196.9kg / cm
² (1200-2800 psig) hydrogen partial pressure, and 0.25
The method of claim 1, wherein the total space velocity is ˜1.8 V _f / hour / V _r . 5. The final stage reaction conditions are 421 to 449 ° C.
Temperature (790-840 ° F), 84.3-196.9kg / cm
² (1200-2800 psig) hydrogen partial pressure, and 0.25
The method of claim 1, wherein the total space velocity is ˜1.8 V _f / hour / V _r . 6. The recirculated vacuum bottoms material is about 454 ° C.
A method according to claim 1 having a nominal boiling point of (850 ° F) or higher. 7. The method of claim 1 wherein the volume ratio of vacuum bottoms recycle to the final stage to fresh feed to the first stage is about 0.2 to 1.5. 8. An activity wherein the catalyst is selected from cadmium, chromium, cobalt, iron, molybdenum, nickel, tin, tungsten and mixtures thereof supported on a support material selected from the group of alumina, silica and combinations thereof. The method according to claim 1, which contains a metal oxide. 9. The method of claim 1 wherein the catalyst in said first and said final stage catalytic reactor is cobalt-molybdenum on an alumina support. 10. A method according to claim 1 wherein the catalyst in said first and said final stage catalytic reactor is nickel-molybdenum on an alumina support. 11. A method according to claim 1 wherein the feedstock is petroleum residual oil. 12. A method according to claim 1 wherein the feedstock is bitumen derived from tar sands. 13. The method of claim 1 wherein the feedstock is raw shale oil. 14. The method according to claim 1, wherein the reaction system comprises two reactors. 15. The method of claim 3 wherein said feedstock comprises a demetallized catalyst containing greater than 300 ppm total metal and containing substantially particulate alumina oxide in said first stage reactor. Method. 16. (a) A hydrocarbon feedstock containing at least 25 V% of a substance boiling at 524 ° C. (975 ° F.) or higher with hydrogen in a first stage catalytic reactor containing a bubbling bed of granular catalyst. Feed the reactor to 421-449 ° C.
(790-840 ° F) temperature, and 0.25-1.8V _f /
Maintaining the total space velocity hr / _{V r,} the feed partially generates hydroconversion flowing material; (b) 415~455 temperature ° C. (seven hundred eighty to eight hundred fifty degrees F),
70.3-210.9kg / cm ² (1000-3000psig)
Through the hydrogen partial pressure, and the 0.20~2.0V f _/ hr / V the partially effluent was hydrogen converted to second stage boiling-bed catalytic reactor maintained at a total space velocity of _r directly further the (B) removing the hydrocarbon gas and the liquid fraction from the second stage reactor and converting the hydrocarbon gas from the liquid fraction to convert the material to hydrogen to produce a hydrocarbon gas and a low boiling liquid fraction; Separation and withdrawing the liquid fraction; (d) distilling the liquid fraction to obtain a temperature of 204.4 to 455 ° C (40
(B) a medium boiling point hydrocarbon liquid product having a normal boiling range of 0-850 ° F) and a vacuum bottoms material having a nominal boiling point of about 455 ° C (850 ° F) or higher; and (e) the vacuum bottoms material. Of at least 0.2 parts by direct recirculation of at least a part of the second stage boiling bed catalytic reactor
Giving a recycled ratio of recycled material to new feedstock of 1.5,
A low-boiling process comprising at least about 75 V% conversion of the 524 ° C. ⁺ (975 ° F ⁺ ) cut to produce the increased yield of the medium boiling hydrocarbon liquid product. A two-step catalytic process for high conversion of petroleum feedstocks that increases the yield of boiling hydrocarbon liquids and gases.