Process and catalyst for upgrading heavy hydrocarbon

Abstract

A catalyst for use in a process for steam conversion of a heavy hydrocarbon feedstock includes the steps of: providing a heavy hydrocarbon feedstock; providing a catalytically active phase comprising a first metal and a second metal wherein said first metal is a non-noble Group VIII metal and said second metal is an alkali metal; and contacting said feedstock with steam at a pressure of less than or equal to about 300 psig in the presence of said catalytically active phase so as to provide a hydrocarbon product having a reduced boiling point. The catalyst may be supported on a support material or mixed directly with the feedstock and comprises a first metal selected from the group consisting of non-noble Group VIII metals and mixtures thereof and a second metal comprising an alkali metal wherein said catalyst is active to convert said heavy hydrocarbon at a pressure of less than or equal to about 300 psig.

Description

vy hydrocarbon feedstock to lighter more valuable hydrocarbon products.ious processes are known in the art for converting heavy hydrocarbonso lighter more valuable liquid and gaseous products. One known processolves thermal cracking such as visbreaking or delayed coking. However,rmal cracking processes typically provide a low rate of conversion (lessn 40% wt), and / or high rate of production of undesirable coke products.ital investment associated with hydrogen generation and compressionilities which require operation at high pressures. An alternative to theegoing processes involves contacting the feedstock with steam. Processeslizing steam are disclosed in U.S. Patent No. 3,676,331 to Pitchford and. Patent No. 4,743,357 to Patel et al. Therocarbons are obtained without high pressure, complicated and costlyipment, or costly ingredients or additives. It is therefore the primaryect of the present invention to provide a process and catalyst for steamversion of heavy hydrocarbons wherein a high rate of conversion toired lower boiling point products is achieved. It is another object ofinvention to provide a process and catalyst for steam conversion ofvyversion of heavy hydrocarbons which utilizes materials which areatively inexpensive and readily available. It is a further object of thesent invention to provide a catalyst and steam conversion process forng the catalyst to convert heavy hydrocarbons wherein high rates ofduction of undesirable coke products are avoided.ention. According to the invention, a process for steam conversion of avy hydrocarbon feedstock is provided which comprises the steps of:viding a heavy hydrocarbon feedstock; providing a catalytically activese comprising a first metal and a second metal wherein said first metala non-noble Group VIII metal and said second metal is an alkali metal;contacting said feedstock with steam at aprises a first metal selected from the group consisting of non-nobleup VIII metals and mixtures thereof and a second metal comprising anali metal wherein said catalyst is active to convert heavy hydrocarbona pressure of less than or equal to about 300 psi. According to theention, said first metal is preferably selected from the groupsisting of iron, cobalt, nickel and mixtures thereof, and said secondal is preferablyvert the feedstock into more desirable lower boiling point products.ording to the invention, heavy hydrocarbon feedstock treated with steamthe presence of the catalyst of the present invention is converted tohter more valuable products. During treatment, hydrogen is transferredm the steam to the hydrocarbon so as to provide a productdstock which fall into four boiling point ranges. The ranges of interestas follows: room temperature to 200[err]C (gasoline); 200[err]C to[err]C (diesel); 350C to 500C (gas-oil); and more than 500[err]Csidue). According to the invention, a process and catalyst are providedconverting the residue fraction having a boiling point greater than[err]C into lower boiling point products having increased commercialue.esirable increases in production of coke and other low value productswithout requiring costly equipment or process additives. The catalystording to the invention comprises an active phase including a firstal and a second metal which in combination serve to provide excellentivity toward the desired conversion reactions in steam treatmentcesses. The metals according to the invention may be supported on aport material or may be provided as an additive for direct mixing withfeedstock as will beording to the invention is an alkali metal, preferably potassium, sodiummixtures thereof. According to the invention, it has been found that thebination of first and second metals as set forth above for use in steamatment of heavy hydrocarbons under low pressures serves to provide anellent rate of conversionention is contacted with the feedstock during steam treatment. Theport material may preferably be selected from the group consisting ofica, aluminosilicate, alumina, carbon based material, and mixturesreof. The support material preferably has a pore volume of at leastut 0.3 ml / g, and may be provided as an extrusion, as a particulate ornular media or powder, or in any other desired form. Examples oftable support materials include silicas, aluminas, both naturalport material by impregnation or dispersion onto the support material inordance with known techniques, or by any other manner known in the art.support material with supported metals is also preferably calcined inordance with known techniques prior to use in the process of the presentention. The catalyst according to the invention may also be provided inform of an additive to be mixed directlysolved into the feedstock. Suitable oil soluble salts include acetyl-tonate salt, salts of fatty or naphthenic acids, organometallicpounds and the like. One or both metals may also be provided accordingthe invention in the form of a water soluble salt to be dissolved in theer phase of a water in oil emulsion which is then mixed with thedstock. Suitable water soluble salts include nitrates, chlorides,fates,dstock. Suitable surfactant includes anionic surfactants such as sodiumpotassium salts of fatty acids or naphthenic acids, soaps, alkylphonates, alkyl ether sulfates and the like. The catalyst according toinvention has been found to provide excellent rates of conversion ofhigh boiling point fractions of a heavy hydrocarbon feedstock when useding steam conversion processes. Such processes are desirable inordance with the invention because steam isth below. The catalyst according to the invention is useful in upgradingvy hydrocarbon feedstock so as to convert high boiling point fractionsthe feedstock into desired lower boiling point products. In furtherordance with the invention, a process is provided whereby a heavyrocarbon feedstock is contacted with steam in the presence of thealyst according to thevision of external hydrogen compression or generation facilities.ording to the invention, the feedstock is contacted with heated steam inpresence of the catalyst according to the invention at a pressure ofs than or equal to about 300 psig, preferably less than 200 psig. Thecess temperature according to the invention is preferably between about[err]C to about 550[err]C, preferably between 380 and 450[err]C. Eitherboth of the steam and feedstock may be preheated prior to entering thector if desired. As set forth above, the catalyst containing the firstording to the invention, one metal may suitably be supported on aport material while the other metal is added directly to the feedstock.ording to the invention, the catalyst in solid form preferably includesfirst and second metals supported on the support material through anyventional manner in and so as to provide a total concentration in the feedstock of at leastut 500 ppm by weight of the feedstock, and preferably of at least 1000. In either form, the catalyst according to the invention has a moleio of second metal (alkali) to first metal (non-noble Group VIII)ater than 0.25 and preferably greater than or equal to 1.0. According toinvention, the process may suitably be carried out in any of numerouses of reactors includingected and the process temperature, and may be as short as a few secondsas long as several hours or more. According to the process of thesent invention, a flow of steam is provided from any convenient source,the catalyst metals are arranged in the reactor or mixed with thedstock as desired. The feedstock is thenvide a more valuable product having lower boiling point and a higherrogen content without the use of external sources of hydrogen gas and atelatively low pressure. As will be demonstrated below, conventionalrmal cracking processes do not significantly increase the amount ofrogen in the hydrocarbon product. According to the process of theention, excellent rates of conversion of the residue fraction of thedstock having a boiling point greater than 500[err]C are accomplished.will be further demonstrated in the examples below,es is reduced during the process. Although the process of the presentention is a desirable alternative for processing any feedstock withnificant amounts of residue fractions, it is preferable that thedstock have a residue content of at least about 50% by weight prior tocessing in accordance with the present invention.dstock into valuable commercial products. The conversion of the residuection of the feedstock having a boiling point greater than 500[err]C aserred to herein is determined as follows: Conversion (%) = [err]rein: R[err] is the amount of hydrocarbon in the feedstock having aling point greater than 500[err]C;the catalyst and process of the present invention. Example 1 Thismple demonstrates the effectiveness of the catalyst of the presentention when the catalyst is directly dispersed into the feedstock ,hout any support. This example also illustrates the activity of thealyst of the present invention compared to a prior art catalystcentration (ppm) 0 1500 300 12000 1500 Group VIII metal conc. (ppm) 0 3000 300 300150 Gases - 11 14 15 810 Liquids 150 120 110 112 122116 Coke - 22 26 21 1924 Liquid product distribution (wt%) IBP-200[err]C11 19 11 11 18 15 230[err]C-350[err]C18 26 19 18 25 23 350[err]C-500[err]C31 52 32 31 49 38 >500[err]C40 3 38 40 8 25 All the trials wereried out under the samed a catalyst according to the prior art. Trial 3 was run with a-noble metal (nickel) only and trial 4 was run with an alkali metaltassium) only. -14- For trials 2-6, iron and nickel were added bysolving the corresponding acetyl-acetonate salts of iron and nickel infeedstock. In trial 6, the barium salt ofrespective alkali salt of oleic acid. The concentration in the finalture for each catalyst is shown in Table 1. The feedstock was a 150 gple of a heavy hydrocarbon containing 83% wt residue material with aling point greater than 500[err]C. A flow of 20 g / hr of water wasped into a heater and the generated steam was bubbled into the reactorough the feedstock. The reactor temperature and pressure were maintained420[err]C and 14 psig respectively for one hour. The feedstock was mixedh the catalyst and heated. While the flow of steam continued, lighter the condenser and its composition determined by gas chromatography.process was run for one hour, with the reactor temperature maintained420C and the flow of water at 20 g / hr. At the end of the treatment, avy liquid fraction that remained in the reactor was separated from theids (coke plus spent catalyst) and combined with the lightdetermined as set forth above (IBP to 200C; 200[err]C to 350C;[err]C to 500[err]C; and greater than 500[err]C). The catalyst of thesent invention (Trials 2 and 5) led to a higher conversion of the highling point fraction when compared with the thermal process (trial 1) andh the catalyst of the prior art (trial 6). Further, the catalyst of thesent invention having a mixture of alkali metal and non-noble Group VIIIal shows conversion rates significantly greater than each of themple illustrates the effectiveness of the catalyst of the presentention when the active phase is dispersed on a solid support. It alsoonstrates that the catalyst is more effective when the process pressureless than 300 psig.port, so as to provide a total metal loading of 3% by weight, at a moleio of potassium to nickel of 4.0. The catalyst was then calcined andded into a fixed bed reactor. The total catalyst volume in the reactor15 ml. The catalyst was exposed to a continuous flow of hydrocarbondstock. The system was operated as a fixed bed reactor with ascendingw of feedstock and steam, under isothermal conditions at 420[err]C, andpace velocity of 1.0 vol feed / vol catalyst / hr. The hydrocarbon feedstockaditions for 6 -17- hours. All liquid and gas products plus noncting steam were collected and separated at the exit of the reactor.e produced during the reaction and deposited on the catalyst surface wassured by weight. Residue conversions obtained after six hours at 150,and 450 psig are set forth below in Table 2.perature ([err]C) 420 420 420 Reactor pressurei) 150 300 450 Reaction time (hr)6.0 6.5 Residue flow rate (mL / hr) 6.34 6.344 Water flow rate (mL / hr) 4.50 4.50 4.50 Residueversion (%) 73 73 58 As shown in Table 2, thealyst of the present invention is most effective when the pressure iss thanrating conditions in a 300 mL stainless steel reactor. Trial 1 was runhout a catalyst according to a standard thermal process. Trials 2 and 3e run with catalysts according to the invention, containing differentarsurfactant was the potassium salt of naphthenic acids from crude oil.concentration in the final mixture for each catalyst is shown in TableThe feedstock was a heavy hydrocarbon containing 83% wt residue materialh a boiling point greater than 500[err]C. Flows of 30 gr / hr of feedstocktaining the catalyst and 20 gr / hr of water were pumped into the reactor.reactor temperature and pressure were maintained at 420[err]C and 14g respectively. Light hydrocarbons, gases and excess steam weretinuously flowing out of the reactor duringer the condenser and its composition determined by gas chromatography.process was run for one hour. At the end of the treatment, a heavyuid fraction that remained -19- in the reactor was separated from theids (coke plus spent catalyst) and combined with the light fractionduced during reaction.ws that the catalyst of the present invention (trials 2 and 3) led toher conversion of the high boiling point fraction when compared with thermal process (trial 1). Table 3 1 2 3 Nickel conc.m) 0 388 388 Potassium conc. (ppm)267 67 Molar Ratio K / Ni - 1.05 Reactor temperature ([err]C) 420 420 42071 57 Example 4 This example further demonstrates theectiveness of the catalyst of the present invention when operated underady state conditions in a continuous flow reactor with a continuousply of catalyst. Three trials are described in this example. Theye carried out under the same operating conditions, with thed as nickel acetyl-acetonate and as a water in oil emulsion where thefactant is the potassium salt of naphthenic acids. Trials for thismple were carried out in a slurry type continuous-flow system. In alles, 315 g / hr of heavy feedstock were pumped from a tank and heated to[err]C in a preheater. 83% by weight of the feedstock had a boilingnt greater than 500[err]C. After the preheater, the feedstock was mixedh a flow of 250 g / hr of steam, also at 200[err]C. The feedstock / steamture was further heated to 350[err]C, and introduced into a reactorre it reached[err]C, where the heavy liquid and solid products were separated fromlight products, gases and excess steam, which were introduced into aling chamber operated at 100[err]C, where the light products and excessam were condensed and separated from the gases. The flow of gases after- separation was measured and the composition of the gastillation, following ASTM standard test method D308, and the fraction oferial in the four above mentioned boiling point ranges was determined.trial 2 a supported catalyst containing nickel and potassium was mixedh the feed. It was prepared following a procedure similar to the onecribed in Example 2, but provided in powder form instead of anrusion. In trial 3 the catalyst was dissolved into the feed in the forman oil soluble nickel salt (acetyl-acetonate)kel concentrations in the feedstock after dispersing the catalyst were0 and 400 ppm respectively. The conditions and results for these trialsshown in Table 4. -22- Table 4 1 2 3Potassium loading in the feed (ppm) 0 12000 Reactor temperature ([err]C) 408 420 425ctor pressure (psi) 150 150 150 Space velocityhr) 0.9 0.6 0.6 Water / feed (wt / wt)0.6 0.6 Residue conversion (%) 4368 Asphaltene conversion (%) -70 19 19e yield (%) 2 5 1gged the reactor and prevented continuous steady state operation. Underconditions employed in trial 1, a heavy hydrocarbon conversion of onlywt was achieved. Furthermore, undesirable asphaltenic compounds wereerated rather than converted. In trial 2, the reaction temperature wassed to 420[err]C, and the residence time was increased to 2 hours. Underse conditions, 56% wt of the heavy hydrocarbon was converted. Theults were evendstock was converted, with a coke yield of only 2% wt. The resultsmarized in Table 4 demonstrate that the catalyst and process of thesent invention allow higher conversions of heavy hydrocarbon and lowere yield under steady state conditions than a conventional thermalcess. This represents a more efficient and economically attractivecess for the conversion of heavy hydrocarbon feedstock into valuableducts.ention. The trials described in this example were identical to trials 12 in Example 1. In this case, however, the hydrogen and carbon contentall the collected products was determined, as was a total hydrogen tobon ratio. Table 5 set forth below shows the results of this example.-1200 Residue conversion (%) - 44Weight of products (gr) 150 153 150 Gases11 14 Liquids 150 120Coke - 22 26 Liquidduct distribution (wt%) IBP-200[err]C 019 200[err]C-350[err]C 0 185 Gases 3.10 3.20 Liquids5 1.50 1.61 Solids 0.421 In the absence of the catalyst according to the present invention, thebined H / C mole ratio of the products was essentially the same as that offeedstock (1.46 vs. 1.45). When the nickel / potassium catalystording to the invention was used, there was an increase in the H / C ratiom 1.45 to 1.55. This indicates that with the use of the catalyst andcess according to the present invention,ce accomplishing the same task using hydrogen gas involves a highital investment associated with the production of hydrogen gas and theh pressures associated therewith. This invention may be embodied iner forms or carried out in other ways without departing from the spiritessential characteristics thereof. The presentning and range of equivalency are intended to be embraced therein.- C L A I M S 1. A process for steam conversion of a heavy hydrocarbondstock, comprising the steps of: providing a heavy hydrocarbondstock; providing a catalytically active phase comprising ag in the presence of said catalytically active phase so as to provide arocarbon product having a reduced boiling point. 2. A processording to claim 1, wherein said first metal is selected from the groupsisting of iron, cobalt, nickel and mixtures thereof and / or wherein saidond metal is selected from the group consisting of potassium, sodium andtures thereof. 3. A process according to claim 1 or 2, furtherprising the step of supporting at least one ofica, both natural and synthetic aluminosilicates, aluminas, cokes fromher petroleum or coals and mesoporous carbon based materials obtainedm either vegetable or animal sources, the said first -27- and secondals may be preferably both supported on said support material and may beferably presenth said feedstock. 6. A process according to claim 5, wherein said atst one metal is mixed with said feedstock in the form of an oil solublet of said at least one metal. 7. A process according to claim 5,rein said mixing step includes the step of mixing said feedstock with aer in oil emulsion and wherein said at least one metal is mixed withd emulsion in the form of a water soluble salt of said at least oneal, or wherein said mixing step includes the step of mixing7, preferably according to claim 5, wherein said first and second metalspresent in a total concentration of at least about 500 ppm andferably of at least 1000 ppm with respect to weight of said feedstock.-al to 1.0. 10. A process according to one of the claims 1 to 4,rein said contacting step is carried out at a temperature of betweenut 320[err]C to about 550[err]C, and preferably between about 380 tout 450[err]C. 11. A process according to one of the claims 1 to 10,rein said process is carried out substantially free of added hydrogener than hydrogen present in said steam. 12. A process according to onethe claims 1 to 11,nt product having a boiling point of less than about 500[err]C, thetial fraction of said feedstock being preferably at least about 50 % wtsaid feedstock. 13. A process according to one of the claims 1 to 12,rein said feedstock is selectedfrom the group consisting of hydrocarbonidue, bitumen and mixtures thereof.tures thereof and.a second metal comprising an alkali metal wherein saidalyst is active to convert said heavy hydrocarbon at a pressure of lessn or equal to about 300 psig. 15. A catalyst according to claim 14,rein said first metal is selected from the group consisting of iron,alt, nickel and mixtures thereof and / or wherein said second metal isected from the groupording to one of the claims 14 to 16, wherein said support material is.ected from the group consisting of silica, natural or syntheticminosilicates, aluminas, cokes from either petroleum or coals, carboned materials obtained from vegetable or animal sources, and mixturesreof and / or wherein said support material has a pore volume of at leastut 0.3 ml / g.ith respect to the total catalyst weight and / or wherein said first metalsaid second metal are present in a mole ratio of second metal to firstal greater than 0.25 and preferably greater than or equal to 1.0. 19.atalyst according to one of the claims 14 to 18, wherein at least one ofd first and second metals is in the from of an oil soluble salt, saidims 14 to 18, wherein at least one of said first and second metals is infrom of a water soluble salt selected from the group consisting ofrates, chlorides, sulfates, acetates and mixtures thereof. 21. Aalyst according to one of the claims 14 to 20, wherein at least one ofd first and second metals is in the form of an surfactant of a water inemulsion.

Claims

What is claimed is:

1. A process for steam conversion of a heavy hydrocarbon feedstock, comprising the steps of:providing a heavy hydrocarbon feedstock;providing a catalytically active phase comprising a first metal and a second metal wherein at least one of the said first metal and said second metal is in the form of an oil soluble compound and wherein said first metal is a non-noble Group VIII metal and said second metal is an alkali metal; andcontacting said feedstock with steam at a pressure of less than or equal to about 300 psig in the presence of said catalytically active phase so as to provide a hydrocarbon product having a reduced boiling point.

2. A process according to claim 1, wherein said first metal is selected from the group consisting of iron, cobalt, nickel and mixtures thereof.

3. A process according to claim 1, wherein said second metal is selected from the group consisting of potassium, sodium and mixtures thereof.

4. A process according to claim 1, further comprising the step of supporting at least one of said first and second metals on a support material.

5. A process according to claim 4, wherein said support material comprises a mesoporous material selected from the group consisting of silica, both natural and Synthetic aluminosilicates, aluminas, cokes from either petroleum or coals and mesoporous carbon based materials obtained from either vegetable or animal sources.

6. A process according to claim 5, wherein said first and second metals are both supported on said support material and are present in an amount of greater than or equal to about 0.5% of the total catalyst weight.

7. A process according to claim 1, further comprising the step of mixing at least one of said first and second metals with said feedstock.

8. A process according to claim 7, wherein said at least one metal is mixed with said feedstock in the form of an oil soluble salt of said at least one metal.

9. A process according to claim 7, wherein said mixing step includes the step of mixing said feedstock with a water in oil emulsion and wherein said at least one metal is mixed with said emulsion in the form of a water soluble salt of said at least one metal.

10. A process according to claim 7, wherein said mixing step includes the step of mixing said feedstock with a water in oil emulsion and wherein said at least one metal is mixed with said emulsion in the form of a surfactant for stabilizing said emulsion.

11. A process according to claim 7, wherein said first and second metals are present in a total concentration of at least about 500 ppm and preferably of at least 1000 ppm with respect to weight of said feedstock.

12. A process according to claim 1, further comprising the step of providing said first and second metals at a mole ratio of second metal to first metal greater than 0.25, and preferably greater than or equal to 1.0.

13. A process according to claim 1, wherein said contacting step is carried out at a temperature of between about 320 DEG C. to about 550 DEG C., and preferably between about 380 DEG to about 450 DEG C.

14. A process according to claim 1, wherein said process is carried out substantially free of added hydrogen other than hydrogen present in said steam.

15. A process according to claim 1, wherein said feedstock has an initial fraction having a boiling point of greater than or equal to about 500 DEG C., and wherein said contacting step converts at least about 50% wt of said initial fraction to a lower boiling point product having a boiling point of less than about 500 DEG C.

16. A process according to claim 15, wherein said initial fraction of said feedstock is at least about 50% wt of said feedstock.

17. A process according to claim 1, wherein said feedstock is selected from the group consisting of hydrocarbon residue, bitumen and mixtures thereof.