Two phase hydroprocessing

A process where the need to circulate hydrogen through the catalyst is eliminated. This is accomplished by mixing and/or flashing the hydrogen and the oil to be treated in the presence of a solvent or diluent in which the hydrogen solubility is “high” relative to the oil feed. The type and amount of diluent added, as well as the reactor conditions, can be set so that all of the hydrogen required in the hydroprocessing reactions is available in solution. The oil/diluent/hydrogen solution can then be fed to a plug flow reactor packed with catalyst where the oil and hydrogen react. No additional hydrogen is required, therefore, hydrogen recirculation is avoided and trickle bed operation of the reactor is avoided. Therefore, the large trickle bed reactors can be replaced by much smaller tubular reactor.

BACKGROUND OF THE INVENTION

The present invention is directed to a two phase hydroprocessing process and apparatus, wherein the need to circulate hydrogen gas through the catalyst is eliminated. This is accomplished by mixing and/or flashing the hydrogen and the oil to be treated in the presence of a solvent or diluent in which the hydrogen solubility is high relative to the oil feed. The present invention is also directed to hydrocracking, hydroisomerization and hydrodemetalization.

In hydroprocessing which includes hydrotreating, hydrofinishing, hydrorefining and hydrocracking, a catalyst is used for reacting hydrogen with a petroleum fraction, distillates or resids, for the purpose of saturating or removing sulfur, nitrogen, oxygen, metals or other contaminants, or for molecular weight reduction (cracking). Catalysts having special surface properties are required in order to provide the necessary activity to accomplish the desired reaction(s).

In conventional hydroprocessing it is necessary to transfer hydrogen from a vapor phase into the liquid phase where it will be available to react with a petroleum molecule at the surface of the catalyst. This is accomplished by circulating very large volumes of hydrogen gas and the oil through a catalyst bed. The oil and the hydrogen flow through the bed and the hydrogen is absorbed into a thin film of oil that is distributed over the catalyst. Because the amount of hydrogen required can be large, 1000 to 5000 SCF/bbl of liquid, the reactors are very large and can operate at severe conditions, from a few hundred psi to as much as 5000 psi, and temperatures from around 400° F.-900° F.

A conventional system for processing is shown in U.S. Pat. No. 4,698,147, issued to McConaghy, Jr. on Oct. 6, 1987 which discloses a SHORT RESIDENCE TIME HYDROGEN DONOR DILUENT CRACKING PROCESS. McConaghy '147 mixes the input flow with a donor diluent to supply the hydrogen for the cracking process. After the cracking process, the mixture is separated into product and spent diluent, and the spent diluent is regenerated by partial hydrogenation and returned to the input flow for the cracking step. Note that McConaghy '147 substantially changes the chemical nature of the donor diluent during the process in order to release the hydrogen necessary for cracking. Also, the McConaghy '147 process is limited by upper temperature restraints due to coil coking, and increased light gas production, which sets an economically imposed limit on the maximum cracking temperature of the process.

U.S. Pat. No. 4,857,168, issued to Kubo et al. on Aug. 15, 1989 discloses a METHOD FOR HYDROCRACKING HEAVY FRACTION OIL. Kubo '168 uses both a donor diluent and hydrogen gas to supply the hydrogen for the catalyst enhanced cracking process. Kubo '168 discloses that a proper supply of heavy fraction oil, donor solvent, hydrogen gas, and catalyst will limit the formation of coke on the catalyst, and the coke formation may be substantially or completely eliminated. Kubo '168 requires a cracking reactor with catalyst and a separate hydrogenating reactor with catalyst. Kubo '168 also relies on the breakdown of the donor diluent for supply hydrogen in the reaction process.

The prior art suffers from the need to add hydrogen gas and/or the added complexity of rehydrogenating the donor solvent used in the cracking process. Hence, there is a need for an improved and simplified hydroprocessing method and apparatus.

BRIEF SUMMARY OF THE INVENTION

In accordance with the present invention, a process has been developed wherein the need to circulate hydrogen gas through the catalyst is eliminated. This is accomplished by mixing and/or flashing the hydrogen and the oil to be treated in the presence of a solvent or diluent in which the hydrogen solubility is “high” relative to the oil feed so that the hydrogen is in solution.

The type and amount of diluent added, as well as the reactor conditions, can be set so that all of the hydrogen required in the hydroprocessing reactions is available in solution. The oil/diluent/hydrogen solution can then be fed to a reactor, such as a plug flow or tubular reactor, packed with catalyst where the oil and hydrogen react. No additional hydrogen is required, therefore, the hydrogen recirculation is avoided and the trickle bed operation of the reactor is avoided. Therefore, the large trickle bed reactors can be replaced by much smaller reactors (seeFIGS. 1,2and3).

The present invention is also directed to hydrocracking, hydroisomerization, hydrodemetalization, and the like. As described above, hydrogen gas is mixed and/or flashed together with the feedstock and a diluent such as recycled hydrocracked product, isomerized product, or recycled demetaled product so as to place hydrogen in solution, and then the mixture is passed over a catalyst.

A principle object of the present invention is the provision of an improved two phase hydroprocessing system, process, method, and/or apparatus.

Another object of the present invention is the provision of an improved hydrocracking. hydroisomerization, Fischer-Tropsch and/or hydrodemetalization process.

Other objects and further scope of the applicability of the present invention will become apparent from the detailed description to follow, taken in conjunction with the accompanying drawings, wherein like parts are designated by like reference numerals.

DETAILED DESCRIPTION OF THE INVENTION

We have developed a process where the need to circulate hydrogen gas or a separate hydrogen phase through the catalyst is eliminated. This is accomplished by mixing and/or flashing the hydrogen and the oil to be treated in the presence of a solvent or diluent having a relatively high solubility for hydrogen so that the hydrogen is in solution.

The type and amount of diluent added, as well as the reactor conditions, can be set so that all of the hydrogen required in the hydroprocessing reactions is available in solution. The oil/diluent/hydrogen solution can then be fed to a plug flow, tubular or other reactor packed with catalyst where the oil and hydrogen react. No additional hydrogen is required, therefore, hydrogen recirculation is avoided and the trickle bed operation of the reactor is avoided. Hence, the large trickle bed reactors can be replaced by much smaller or simpler reactors (seeFIGS. 1,2and3).

In addition to using much smaller or simpler reactors, the use of a hydrogen recycle compressor is avoided. Because all of the hydrogen required for the reaction is made available in solution ahead of the reactor there is no need to circulate hydrogen gas within the reactor and no need for the recycle compressor. Elimination of the recycle compressor and the use of, for example, plug flow or tubular reactors greatly reduces the capital cost of the hydrotreating process.

Most of the reactions that take place in hydroprocessing are highly exothermic and as a result a great deal of heat is generated in the reactor. The temperature of the reactor can be controlled by using a recycle stream. A controlled volume of reactor effluent can be recycled back to the front of the reactor and blended with fresh feed and hydrogen. The recycle stream absorbs some of the heat and reduces the temperature rise through the reactor. The reactor temperature can be controlled by controlling the fresh feed temperature and the amount of recycle. In addition, because the recycle stream contains molecules that have already reacted, it also serves as an inert diluent.

One of the biggest problems with hydroprocessing is catalyst coking. Because the reaction conditions can be quite severe cracking can take place on the surface of the catalyst. If the amount of hydrogen available is not sufficient, the cracking can lead to coke formation and deactivate the catalyst. Using the present invention for hydroprocessing, coking can be nearly eliminated because there is always enough hydrogen available in solution to avoid coking when cracking reactions take place. This can lead to much longer catalyst life and reduced operating and maintenance costs.

FIG. 1shows a schematic process flow diagram for a diesel hydrotreater generally designated by the numeral10. Fresh feed stock12is pumped by feed charge pump14to combination area18. The fresh feed stock12is then combined with hydrogen15and hydrotreated feed16to form fresh feed mixture20. Mixture20is then separated in separator22to form first separator waste gases24and separated mixture30. Separated mixture30is combined with catalyst32in reactor34to form reacted mixture40. The reacted mixture40is split into two product flows. recycle flow42and continuing flow50. Recycle flow42is pumped by recycle pump44to become the hydrotreated feed16which is combined with the fresh feed12and hydrogen15.

Continuing flow50flows into separator52where second separator waste gases54are removed to create the reacted separated flow60. Reacted separated flow60then flows into flasher62to form flasher waste gases64and reacted separated flashed flow70. The reacted separated flashed flow70is then pumped into stripper72where stripper waste gases74are removed to form the output product80.

FIG. 2shows a schematic process flow diagram for a resid hydrotreater generally designated by the numeral100. Fresh feed stock110is combined with solvent112at combination area114to form combined solvent-feed120. Combined solvent-feed120is the pumped by solvent-feed charge pump122to combination area124. The combined solvent-feed120is then combined with hydrogen126and hydrotreated feed128to form hydrogen-solvent-feed mixture130. Hydrogen-solvent-feed mixture130is then separated in first separator132to form first separator waste gases134and separated mixture140. Separated mixture140is combined with catalyst142in reactor144to form reacted mixture150. The reacted mixture150is split into two product flows, recycle flow152and continuing flow160. Recycle flow152is pumped by recycle pump154to become the hydrotreated feed128which is combined with the solvent-feed120and hydrogen126.

Continuing flow160flows into second separator162where second separator waste gases164are removed to create the reacted separated flow170. Reacted separated flow170then flows into flasher172to form flasher waste gases174and reacted separated flashed flow180. The flasher waste gases174are cooled by condenser176to form solvent112which is combined with the incoming fresh feed110.

The reacted separated flashed flow180then flows into stripper182where stripper waste gases184are removed to form the output product190.

FIG. 3shows a schematic process flow diagram for a hydroprocessing unit generally designated by the numeral200.

Fresh feed stock202is combined with a first diluent204at first combination area206to form first diluent-feed208. First diluent-feed208is then combined with a second diluent210at second combination area212to form second diluent-feed214. Second diluent-feed214is then pumped by diluent-feed charge pump216to third combination area218.

Hydrogen220is input into hydrogen compressor222to make compressed hydrogen224. The compressed hydrogen224flows to third combination area218.

Second diluent-feed214and compressed hydrogen224are combined at third combination area218to form hydrogen-diluent-feed mixture226. The hydrogen-diluent-feed mixture226then flows though feed-product exchanger228which warms the mixture226, by use of the third separator exhaust230, to form the first exchanger flow232. First exchanger flow232and first recycle flow234are combined at forth combination area236to form first recycle feed238.

The first recycle feed238then flows though first feed-product exchanger240which warms the mixture238, by use of the exchanged first rectifier exchanged exhaust242, to form the second exchanger flow244. Second exchanger flow244and second recycle flow246are combined at fifth combination area248to form second recycle feed250.

The second recycle feed250is then mixed in feed-recycle mixer252to form feed-recycle mixture254. Feed-recycle mixture254then flows into reactor inlet separator256.

Feed-recycle mixture254is separated in reactor inlet separator256to form reactor inlet separator waste gases258and inlet separated mixture260. The reactor inlet separator waste gases258are flared or otherwise removed from the present system200.

Reacted mixture266is separated in reactor outlet separator268to form reactor outlet separator waste gases270and outlet separated mixture272. Reactor outlet separator waste gases270flow from the reactor outlet separator268and are then flared or otherwise removed from the present system200.

Outlet separated mixture272flows out of reactor outlet separator268and is split into large recycle flow274and continuing outlet separated mixture276at first split area278.

Large recycle flow274is pumped through recycle pumps280to second split area282. Large recycle flow274is split at combination area282into first recycle flow234and second recycle flow246which are used as previously discussed.

Continuing outlet separated mixture276leaves first split area278and flows into effluent heater284to become heated effluent flow286.

Heated effluent flow286flows into first rectifier288where it is split into first rectifier exhaust290and first rectifier flow292. First rectifier exhaust290and first rectifier flow292separately flow into second exchanger294where their temperatures difference is reduced.

The exchanger transforms first rectifier exhaust290into first rectifier exchanged exhaust242which flows to first feed-product exchanger240as previously described. First feed-product exchanger240cools first rectifier exchanged exhaust242even further to form first double cooled exhaust296.

First double cooled exhaust296is then cooled by condenser298to become first condensed exhaust300. First condensed exhaust300then flows into reflux accumulator302where it is split into exhaust304and first diluent204. Exhaust304is exhausted from the system200. First diluent204flows to first combination area206to combine with the fresh feed stock202as previously discussed.

The exchanger transforms first rectifier flow292into first rectifier exchanged flow306which flows into third separator308. Third separator308splits first rectifier exchanged flow306into third separator exhaust230and second rectified flow310.

Second cooled exhaust312is then cooled by condenser314to become third condensed exhaust316. Third condensed exhaust316then flows into reflux accumulator318where it is split into reflux accumulator exhaust320and second diluent210. Reflux accumulator exhaust320is exhausted from the system200. Second diluent210flows to second combination area212to rejoin the system200as previously discussed.

Second rectified flow310flows into second rectifier322where it is split into third rectifier exhaust324and first end flow326. First end flow326then exits the system200for use or further processing. Third rectifier exhaust324flows into condenser328where it is cooled to become third condensed exhaust330.

Third condensed exhaust330flows from condenser328into fourth separator332. Fourth separator332splits third condensed exhaust330into fourth separator exhaust334and second end flow336. Fourth separator exhaust334is exhausted from the system200. Second end flow336then exits the system200for use or further processing.

FIG. 4shows a schematic process flow diagram for a 1200 BPSD hydroprocessing unit generally designated by the numeral400.

Fresh feed stock401is monitored at first monitoring point402for acceptable input parameters of approximately 260° F., at 20 psi, and 1200 BBL/D. The fresh feed stock401is then combined with a diluent404at first combination area406to form combined diluent-feed408. Combined diluent-feed408is the pumped by diluent-feed charge pump410through first monitoring orifice412and first valve414to second combination area416.

Hydrogen420is input at parameters of 100° F., 500 psi, and 40000 SCF/HR into hydrogen compressor422to make compressed hydrogen424. The hydrogen compressor422compresses the hydrogen420to 1500 psi. The compressed hydrogen424flows through second monitoring point426where it is monitored for acceptable input parameters. The compressed hydrogen424flows through second monitoring orifice428and second valve430to second combination area416.

First monitoring orifice412, first valve414, and FFIC434are connected to FIC432which controls the incoming flow of combined diluent-feed408to second combination area416. Similarly, second monitoring orifice428, second valve430, and FIC432are connected to FFIC434which controls the incoming flow of compressed hydrogen424to second combination area416. Combined diluent-feed408and compressed hydrogen424are combined at second combination area416to form hydrogen-diluent-feed mixture440. The mixture parameters are approximately 1500 psi and 2516 BBL/D which are monitored at fourth monitoring point442. The hydrogen-diluent-feed mixture440then flows though feed-product exchanger444which warms the hydrogen-diluent-feed mixture440, by use of the rectified product610, to form the exchanger flow446. The feed-product exchanger444works at approximately 2.584 MMBTU/HR.

The exchanger flow446is monitored at fifth monitoring point448to gather information about the parameters of the exchanger flow446.

The exchanger flow446then travels into the reactor preheater450which is capable of heating the exchange flow446at 5.0 MMBTU/HR to create the preheated flow452. Preheated flow452is monitored at sixth monitoring point454and by TIC456.

Fuel gas458flows though third valve460and is monitored by PIC462to supply the fuel for the reactor preheater450. PIC462is connected to third valve460and TIC456.

Feed-recycle mixture474is separated in reactor inlet separator476to form reactor inlet separator waste gases478and inlet separated mixture480. Reactor inlet separator waste gases478flow from the reactor inlet separator476through third monitoring orifice482which is connected to FI484. The reactor inlet separator waste gases478then travel through fourth valve486, past eighth monitoring point488and are then flared or otherwise removed from the present system400.

LIC490is connected to both fourth valve486and reactor inlet separator476.

Inlet separated mixture480flows out of the reactor inlet separator476with parameters of approximately 590° F. and 1500 psi which are monitored at ninth monitoring point500.

Inlet separated mixture480is combined with catalyst502in reactor504to form reacted mixture506. Reacted mixture506is monitored by TIC508and at tenth monitoring point510for processing control. The reacted mixture506has parameters of 605° F. and 1450 psi as it flows into reactor outlet separator512.

Reacted mixture506is separated in reactor outlet separator512to form reactor outlet separator waste gases514and outlet separated mixture516. Reactor outlet separator waste gases514flow from the reactor outlet separator512through monitor515for PIC518. The reactor outlet separator waste gases514then travel past eleventh monitoring point520and through fifth valve522and are then flared or otherwise removed from the present system400.

The reactor outlet separator512is connected to controller LIC524. The reactor outlet separator512has parameters of 60″ I.D.×10′-0″ S/S.

Outlet separated mixture516flows out of reactor outlet separator512and is split into both recycle flow464and continuing outlet separated mixture526at first split area528.

Recycle flow464is pumped through recycle pumps530and past twelfth monitoring point532to fourth monitoring orifice534. Fourth monitoring orifice534is connected to FIC536which is connected to TIC508. FIC536controls sixth valve538. After the recycle flow464leaves fourth monitoring orifice534, the flow464flows through sixth valve538and on to third combination area466where it combines with preheated flow452as previously discussed.

Outlet separated mixture526leaves first split area528and flows through seventh valve540which is controlled by LIC524. Outlet separated mixture526then flows past thirteenth monitoring point542to effluent heater544.

Outlet separated mixture526then travels into the effluent heater544which is capable of heating the outlet separated mixture526at 3.0 MMBTU/HR to create the heated effluent flow546. The heated effluent flow546is monitored by TIC548and at fourteenth monitoring point550. Fuel gas552flows though eighth valve554and is monitored by PIC556to supply the fuel for the effluent heater544. PIC556is connected to eighth valve554and TIC548.

Drain stream576flows out of rectifier reflux accumulator574and past monitor578out of the system400.

Gas stream580flows out of rectifier reflux accumulator574, past a monitoring for PIC582, through ninth valve584, past fifteenth monitoring point586and exits the system400. Ninth valve584is controlled by PIC582.

Diluent stream590flows out of rectifier reflux accumulator574, past eighteenth monitoring point594and through pump596to form pumped diluent stream598. Pumped diluent stream598is then split into diluent404and return diluent flow560at second split area600. Diluent404flows from second split area600, through tenth valve602and third monitoring point604. Diluent404then flows from third monitoring point604to first combination area406where it combines with fresh feed stock401as previously discussed.

Return diluent flow560flows from second split area600, past nineteenth monitoring point606, through eleventh valve608and into rectifier552. Eleventh valve608is connected to TIC564.

Rectified product610flows out of rectifier552, past twenty first monitoring point612and into exchanger444to form exchanged rectified product614. Exchanged rectified product614then flows past twenty second monitoring point615and through product pump616. Exchanged rectified product614flows from pump616through fifth monitoring orifice618. Sixth monitoring orifice618is connected to FI620. Exchanged rectified product then flows from sixth monitoring orifice618to twelfth valve622. Twelfth valve622is connected to LIC554. Exchanged rectified product614then flows from twelfth valve622through twenty third monitoring point624and into product cooler626where it is cooled to form final product632. Product Cooler626uses CWS/R628. Product cooler has parameters of 0.640 MMBTU/HR. Final product632flows out of cooler626, past twenty fourth monitoring point630and out of the system400.

FIG. 5shows a schematic process flow diagram for a multistage hydrotreater generally designated by the numeral700. Feed710is combined with hydrogen712and first recycle stream714in area716to form combined feed-hydrogen-recycle stream720. The combined feed-hydrogen-recycle stream720flows into first reactor724where it is reacted to form first reactor output flow730. The first reactor output flow730is divided to form first recycle stream714and first continuing reactor flow740at area732. First continuing reactor flow740flows into stripper742where stripper waste gases744such as H2S, NH3, and H2O are removed to form stripped flow750.

Stripped flow750is then combined with additional hydrogen752and second recycle stream754in area756to form combined stripped-hydrogen-recycle stream760. The combined stripped-hydrogen-recycle stream760flows into saturation reactor764where it is reacted to form second reactor output flow770. The second reactor output flow770is divided at area772to form second recycle stream754and product output780.

A feed selected from the group of petroleum fractions, distillates, resids, waxes, lubes, DAO, or fuels other than diesel fuel is hydrotreated at 620 K to remove sulfur and nitrogen. Approximately 200 SCF of hydrogen must be reacted per barrel of diesel fuel to make specification product. The diluent is selected from the group of propane, butane, pentane, light hydrocarbons, light distillates, naptha, diesel, VG0, previously hydroprocessed stocks, or combinations thereof. A tubular reactor operating at 620 K outlet temperature with a 1/1 or 2/1 recycle to feed ratio at 65 or 95 bar is sufficient to accomplish the desired reactions.

A feed selected from the group of petroleum fractions, distillates, resids, oils, waxes, lubes, DAO, or the like other than deasphalted oil is hydrotreated at 620 K to remove sulfur and nitrogen and to saturate aromatics. Approximately 1000 SCF of hydrogen must be reacted per barrel of deasphalted oil to make specification produce. The diluent is selected from the group of propane, butane, pentane, light hydrocarbons, light distillates, naptha, diesel, VG0, previously hydroprocessed stocks, or combinations thereof. A tubular reactor operating at a 620 K outlet temperature and 80 bar with a recycle ratio of 2.5/1 is sufficient to provide all of the hydrogen required and allow for a less than 20 K temperature rise through the reactor.

A two phase hydroprocessing method and apparatus as described and shown herein.

In a hydroprocessing method, the improvement comprising the step of mixing and/or flashing the hydrogen and the oil to be treated in the presence of a solvent or diluent in which the hydrogen solubility is high relative to the oil feed.

The Example 4 above wherein the solvent or diluent is selected from the group of heavy naptha, propane, butane, pentane, light hydrocarbons, light distillates, naptha, diesel, VG0, previously hydroprocessed stocks, or combinations thereof.

The Example 5 above wherein the feed is selected from the group of oil, petroleum fraction, distillate, resid, diesel fuel, deasphalted oil, waxes, lubes, and the like.

A two phase hydroprocessing method comprising the steps of blending a feed with a diluent, saturating the diluent/feed mixture with hydrogen ahead of a reactor, reacting the feed/diluent/hydrogen mixture with a catalyst in the reactor to saturate or remove sulphur, nitrogen, oxygen, metals, or other contaminants, or for molecular weight reduction or cracking.

The Example 7 above wherein the reactor is kept at a pressure of 500-5000 psi, preferably 1000-3000 psi.

The Example 8 above further comprising the step of running the reactor at super critical solution conditions so that there is no solubility limit.

The Example 9 above further comprising the step of removing heat from the reactor affluent, separating the diluent from the reacted feed, and recycling the diluent to a point upstream of the reactor.

A hydroprocessed, hydrotreated, hydrofinished, hydrorefined, hydrocracked, or the like petroleum product produced by one of the above described Examples.

A reactor vessel for use in the improved hydrotreating process of the present invention includes catalyst in relatively small tubes of 2-inch diameter, with an approximate reactor volume of 40 ft.3, and with the reactor built to withstand pressures of up to about only 3000 psi.

In a solvent deasphalting process eight volumes of n butane are contacted with one volume of vacuum tower bottoms. After removing the pitch but prior to recovering the solvent from the deasphalted oil (DAO) the solvent/DAO mix is pumped to approximately 1000-1500 psi and mixed with hydrogen, approximately 900 SCF H2per barrel of DAO. The solvent/DAO/H2mix is heated to approximately 590K-620K and contacted with catalyst for removal of sulfur, nitrogen and saturation of aromatics. After hydrotreating the butane is recovered from the hydrotreated DAO by reducing the pressure to approximately 600 psi.

At least one of the examples above including multi-stage reactors, wherein two or more reactors are placed in series with the reactors configured in accordance with the present invention and having the reactors being the same or different with respect to temperature, pressure, catalyst. or the like.

Further to Example 14 above, using multi-stage reactors to produce specialty products, waxes, lubes, and the like.

Briefly, hydrocracking is the breaking of carbon-carbon bonds and hydroisomerization is the rearrangement of carbon-carbon bonds. Hydrodemetalization is the removal of metals, usually from vacuum tower bottoms or deasphalted oil, to avoid catalyst poisoning in cat crackers and hydrocrackers.

Hydrocracking: A volume of vacuum gas oil is mixed with 1000 SCF H2per barrel of gas oil feed and blended with two volumes of recycled hydrocracked product (diluent) and passed over a hydrocracking catalyst of 750° F. and 2000 psi. The hydrocracked product contained 20 percent naphtha, 40 percent diesel and 40 percent resid.

Hydroisomerization: A volume of feed containing 80 percent paraffin wax is mixed with 200 SCF H2per barrel of feed and blended with one volume if isomerized product as diluent and passed over an isomerization catalyst at 550° F. and 2000 psi. The isomerized product has a pour point of 30° F. and a VI of 140.

Hydrodemetalization: A volume of feed containing 80 ppm total metals is blended with 150 SCF H2per barrel and mixed with one volume of recycled demetaled product and passed over a catalyst at 450° F. and 1000 psi. The product contained 3 ppm total metals.

Generally, Fischer-Tropsch refers to the production of paraffins from carbon monoxide and hydrogen (CO & H2or synthesis gas). Synthesis gas contains CO2, CO and H2and is produced from various sources, primarily coal or natural gas. The synthesis gas is then reacted over specific catalysts to produce specific products.

Fischer-Tropsch synthesis is the production of hydrocarbons, almost exclusively paraffins, from CO and H2over a supported metal catalyst. The classic Fischer-Tropsch catalyst is iron, however other metal catalysts are also used.

Synthesis gas can and is used to produce other chemicals as well, primarily alcohols, although these are not Fischer-Tropsch reactions. The technology of the present invention can be used for any catalytic process where one or more components must be transferred from the gas phase to the liquid phase for reaction on the catalyst surface.

A two stage hydroprocessing method, wherein the first stage is operated at conditions sufficient for removal of sulfur, nitrogen, oxygen, and the like (620 K. 100 psi), after which the contaminants H2S, NH3and water are removed and a second stage reactor is then operated at conditions sufficient for aromatic saturation.

The process as recited in at least one of the examples above, wherein in addition to hydrogen. carbon monoxide (CO) is mixed with the hydrogen and the mixture is contacted with a Fischer-Tropsch catalyst for the synthesis of hydrocarbon chemicals.

In accordance with the present invention, an improved hydroprocessing, hydrotreating, hydrofinishing, hydrorefining, and/or hydrocracking process provides for the removal of impurities from lube oils and waxes at a relatively low pressure and with a minimum amount of catalyst by reducing or eliminating the need to force hydrogen into solution by pressure in the reactor vessel and by increasing the solubility for hydrogen by adding a diluent or a solvent. For example, a diluent for a heavy cut is diesel fuel and a diluent for a light cut is pentane. Moreover, while using pentane as a diluent, one can achieve high solubility. Further, using the process of the present invention, one can achieve more than a stoichiometric requirement of hydrogen in solution. Also, by utilizing the process of the present invention, one can reduce cost of the pressure vessel and can use catalyst in small tubes in the reactor and thereby reduce cost. Further, by utilizing the process of the present invention, one may be able to eliminate the need for a hydrogen recycle compressor.

Although the process of the present invention can be utilized in conventional equipment for hydroprocessing, hydrotreating, hydrofinishing, hydrorefining, and/or hydrocracking, one can achieve the same or a better result using lower cost equipment, reactors, hydrogen compressors, and the like by being able to run the process at a lower pressure, and/or recycling solvent, diluent, hydrogen, or at least a portion of the previously hydroprocessed stock or feed.