Feed mixture for producing hydrocarbons
10428276 · 2019-10-01
Assignee
Inventors
Cpc classification
C10G1/008
CHEMISTRY; METALLURGY
Y02E50/10
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
Y02P30/20
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
International classification
Abstract
The invention relates to a feed mixture for use in a process for producing hydrocarbons under increased pressure and temperature conditions, where the feed mixture comprises one or more carbonaceous feedstocks and water, where further a texturing agent has been added to the feed mixture, the texturing agent being adapted to stabilize the feed mixture to prevent separation and further to maintain the feed mixture as a homogenous mixture during a pressurization. Further the invention relates to processes for manufacturing such feed mixture.
Claims
1. A process for producing hydrocarbons comprising: combining one or more carbonaceous feedstocks with water and an additional component of a texturing agent to obtain a feed mixture; pressurizing said feed mixture to a pressure substantially in a range of 150 to 375 bar; and heating the pressurized feed mixture to a temperature substantially in a range of 300 to 430 C., wherein the texturing agent is adapted to stabilize the feed mixture to prevent separation and further to maintain the feed mixture as a homogenous mixture during the pressurizing step, wherein the texturing agent is adapted to be converted or degraded during the hydrocarbon production process, and wherein the texturing agent comprises a derivative of a cellulosic material and is selected from microcrystalline cellulose (MCC), nanocrystalline cellulose (NCC), polyanionic cellulose (PAC), a derivative of methylcellulose, and a combination thereof.
2. A process according to claim 1, wherein said pressurizing step pressurizes said feed mixture to a pressure of at least 218 bars.
3. A process according to claim 1, wherein the heating step heats the pressurized feed mixture to a temperature of at least 350 C.
4. A process according to claim 1, wherein said one or more carbonaceous material comprises lignocellulosic material.
5. A process according to claim 1, wherein the texturing agent is added in a concentration of 1-50% by weight of total dry matter content of said one or more carbonaceous feedstocks.
6. A process according to claim 1, further comprising treating part of said one or more carbonaceous feedstocks with a base at a temperature in the range of 150 to 230 C. to produce a pulp.
7. A process according to claim 6, wherein the base is selected from sodium hydroxide, potassium hydroxide, potassium carbonate, ammonia, and a combination thereof.
8. A process according to claim 7, wherein the concentration of said base added to produce said pulp is in the range 5 to 30 percent by weight.
9. A process according to claim 6, further comprising adding water soluble organics to the part of said one or more carbonaceous feedstocks before or during the treatment of part of said one or more carbonaceous feedstocks.
10. A process according to claim 9, wherein said water soluble organics comprise at least one of the following: an alcohol having a carbon chain length of 1-6, a phenol or phenol derivative, a catechol, a ketone having a chain length of 1-6, and organic acids having a chain length of 1-6.
11. A process according to claim 10, wherein said water soluble organics comprise glycerine, said texturing agent being different from said water soluble organics.
12. A process according to claim 10, wherein said water soluble organics are present in a concentration in the range 5-40% by weight.
13. A process according to claim 6, wherein the part of the one or more carbonaceous feedstocks being treated is in the range 20% to 80% by weight of the total carbonaceous feedstock in the feed mixture.
14. A process according to claim 1, wherein the texturing agent is a derivative of methylcellulose selected from carboxymethylcellulose (CMC) and hydroxypropyl methylcellulose, and a combination thereof.
15. A process according to claim 14, where the texturing agent comprises a carboxy methyl cellulose (CMC).
16. A process according to claim 1, wherein the molecular weight of said texturing agent is in the range 10000 to 1000000.
17. A feed mixture according to claim 1, wherein a degree of polymerization of said texturing agent is in the range 100 to 5000 repeat units.
18. A process according to claim 1, wherein a degree of substitution of said texturing agent is in the range 0.5-1.5.
19. A process according to claim 1, wherein the texturing agent is added in a concentration of 0.01 to 10% by weight.
20. A process according to claim 1, wherein a concentration of water in the feed mixture is less than 75% by weight.
21. A process according to claim 1, wherein a concentration of water in the feed mixture is at least 25% by weight.
22. A process according to claim 1, wherein a concentration of water in the feed mixture is in the range of 15 to 75% t.
23. A process according to claim 1, wherein the feed mixture includes at least one liquid organic compound that is a desired product that is at least partly produced within the process, wherein the concentration of said liquid organic compound contained in the feed mixture is at least 10% by weight.
24. A process according to claim 23, wherein said liquid organic compound comprises hydrocarbons produced by the process.
25. A process according to claim 24, wherein the concentrations of said hydrocarbons produced by the process is at least 10% by weight.
26. A process according to claim 23, wherein said liquid organic compound comprises water soluble organics produced by the process.
27. A process according to claim 26, wherein the concentration of said water soluble organics is in a concentration of at least 2% by weight.
28. A process according to claim 26, wherein the concentration of said water soluble organics is in the range 2 to 40% by weight.
29. A process according to claim 23, wherein the ratio of weight of said one or more liquid organic compounds to the dry weight of carbonaceous material in said feed mixture is in the range 0.1 to 2.0.
30. A process according to claim 1, wherein the feed mixture provided contains at least one homogeneous catalyst in the form of a compound of potassium and/or sodium so as to ensure a total concentration of potassium and sodium of at least 0.5% by weight.
31. A process according to claim 30, wherein the concentration of the homogeneous catalysts and base in the feed mixture are controlled so as to maintain a pH in the range of 6.5-14 at any location of the conversion process of said one or more carbonaceous materials.
32. A process according to claim 1, wherein the pH of said feed mixture is in the range of 7-14.
33. A process according to claim 1, wherein the feed mixture comprises a dry solid content of carbonaceous material in the range 15 to 60% dry matter by weight.
34. A process according to claim 1, wherein the feed mixture comprises a dry solid content of carbonaceous material that is in a concentration of at least 15% dry matter by weight.
35. A process according to claim 1, wherein the feed mixture comprises a dry solid content of carbonaceous material in the range 15 to 50% by weight.
36. A process according to claim 1, wherein the feed mixture comprises carbonaceous particles with a particle size of maximum 5 mm.
37. A process according to claim 1, wherein the viscosity of said feed mixture is in the range of 500 to 100000 cP at room temperature.
38. A process according to claim 1, wherein the feed mixture is further provided with a homogenous catalysts in the form of a compound of potassium and/or sodium, and a desired content of liquid organic compound, and wherein the one or more carbonaceous feedstocks, the water, the texturing agent, the homogeneous catalyst, and the liquid organic compound is mixed for a sufficient time to provide a homogeneous feed mixture.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1)
(2)
(3)
DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION
(4) The method and apparatus according to the invention will now be described in more detail with regard to the accompanying figures. The figures show one way of implementing the present invention and is not to be construed as being limiting to other possible embodiments falling within the scope of the attached claim set.
(5)
(6) The carbonaceous material to be converted in a process may be contained in one or more feedstock. The feedstock may be on a solid form or may have a solid appearance, but may also be in the form of sludge or a liquid. The desired dry solid content of the feed mixture according to many embodiments of the present invention is at least 20% by weight such as at least 25% by weight, and preferably the dry solid content of said carbonaceous material is at least 30% by weight such as at least 40% by weight. Characterizing for the feed mixture is the content of a texturizing agent that will ensure that the feed mixture remains homogeneous prior to entering the process and further during pressurization in the process.
(7) Non-limiting examples of suitable carbonaceous feedstock that may be converted by a process according to the present invention include ancient biomass such as low rank coals such as lignite, sub bituminous coals, peat, moss, spaghnum; biomass such as wood, wood chips, sawdust, forestry thinnings and waste, shavings, slash, bark, leaves, off spec fibres from paper production, paper sludge, lignin, cellulose, hemicellulose, sugars, protein, wine trash and agricultural residues and byproducts such as grasses, straw, stems, stover, husk, cobs, shells from e.g. wheat, rye, corn, rice, sunflowers; empty fruit bunches from palm oil production, palm oil manufacturers effluent (POME, bagasse), manure fibres from livestock production, greenhouse waste, garden waste and weeds; energy crops like jatropha, sorghum, switchgrass and miscanthus; aquatic biomass such as macroalgae, microalgae, bacteria such as cyanobacteria; waste, residues and byproducts from industry such as residues from olive production, residues and byproducts from juice production, residue from wine production, residues, byproducts and waste streams from vegetable oil production; Residues, byproducts and waste from food production such as brewers spent grains and yeast; residues and byproducts from fruit and vegetable processing such as pulp; residues and byproducts from fermentation processes such as wet distillers grain, vinasse, molasses, black liquor from paper production, aerobic and anaerobic digested sludges e.g. sewage sludge from wastewater cleaning and/or digested sludge from biogasification, leachate, clarifier sludge, paper waste, green fraction of household waste, restaurant waste, slaughter house waste, risk material from meat and bone processing, municipal solid waste, used and recycle oils, fat, organic solvents, glycerine such as crude glycerine from biodiesel production, refinery wastes, plastic and polymers and combinations thereof.
(8) A particularly preferred embodiment is where said one or more carbonaceous material comprises lignocellulosic material.
(9) A further preferred embodiment is where the carbonaceous material in the feed is provided from at least two different feed stocks.
(10) The carbonaceous material in said one or more feedstock is added to a pretreatment step, wherein said feed stock is transformed into a feed mixture in the form of a pumpable slurry or paste according to the present invention.
(11) Said addition may involve controlling the maximum particle size to less than 30 mm such as a particle size of maximum 10 mm, and preferably a particle size of maximum 5 mm such as a particle size of maximum 1 mm, and even more preferably a particle size of maximum 0.5 mm such as a particle size of less than 0.25 mm.
(12) Depending of the character of the specific feedstock, said controlling of the particle size may comprise one or more of the operations of sieving, filtering, and/or settling operation and/or size reduction by one or more crushing, cutting, grinding, attriting and/or milling operations.
(13) Control of maximum particle size in the pre-treating is important for the rheological properties of the feed mixture and also for the mass- and heat transfer within the particles during said second step of converting.
(14) In many embodiments of the present invention said one or more carbonaceous feedstocks comprises a fibous lignocellulosic material. Many size reduction techniques for such fibrous materials are available for dry materials e.g. knife mills, hammer mills, impeller mills, cone mills and stone mills or combinations thereof. Further a wide range of techniques are available for wet materials at low materials including different kind of wet milling techniques such as ball mills, colloidal mills, cutting mills, macerators, etc.
(15) At moisture contents up 20-30% such materials can be milled as is to particles sizes well below 1 mm in most dry milling systems such as hammermills without interrupting the operation of the mill due to clogging of the screens due to the moisture content. However, for more moist materials such as materials having a moisture content in the range 20 to 60% such size reduction is demanding without drying the feedstock material. Drying of the feedstock material is energy intensive and normally undesired. Such milling is according to an embodiment of the present invention performed using a hammer mill with a controlled vacuum on the screen for prevention of clogging of the screen. In another embodiment according to the present invention clogging of the said screens in the hammer mill may be prevented by mixing the moist material with a drier material.
(16) However, even with a size reduction to a particle size of less than 250 m feedstock such as lignocellulosic materials can be difficult to wet and to prepare as a homogenous feed mixture at desired dry solid contents having proper rhelogical properties for pumping to an elevated pressure without squeezing the fluid out of said feed mixture thereby leaving a solid clog of the carbonaceous feedstock in the pump and/or check valves.
(17) Hence, a preferred embodiment for preparing a feed mixture suitable for use in a process for producing liquid hydrocarbons at elevated pressure and temperature according to the present invention comprises: a. Providing at least one feedstock of carbonaceous material; b. Providing a desired water content; c. Providing a desired content of homogeneous catalyst in the form of a compound of potassium and/or sodium; d. Providing a desired content of liquid organic compounds e. Providing at least one texturing agent adapted to stabilize the feed mixture in a preprocess condition and further during pressurization; f. Mixing the ingredients a)-e) for a time sufficient to provide a homogeneous feed mixture.
(18) Water is important for the desired conversion of the carbonaceous material to proceed, and according to an embodiment of the present invention it needs to be within certain ranges. The desired concentration of water generally is less than 75% by weight such as less than 65% by weight, preferably less than 60% by weight such as less than 55% by weight, more preferably less than 50% by weight.
(19) Further the content of water is generally at least 15% by weight such as at least 30% by weight, preferably at least 35% by weight such as at least 40% by weight, more preferably at least 45% by weight such as at least 50% by weight.
(20) Hence, the feed mixture according to an embodiment the present invention further comprises water in an amount of at least 25% such as at least 40%, and preferably the water content of said feed mixture is in the range 30 to 80% such as in the range 30 to 70%. Advantageously, the water content in said feed mixture is in the range 40-60% by weight.
(21) The desired content of homogenous catalyst in the form of potassium and/or sodium is advantageously a total concentration of at least 0.5% by weight. preferably 1-10% by weight, more preferably in the range 2-5% by weight. Preferred forms of potassium and/or sodium according to the present invention include potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, potassium bicarbonate, sodium bicarbonate, potassium formate, sodium formate, potassium acetate, sodium acetate, potassium citrate, sodium citrate. In some embodiments of the present invention said addition of potassium and/or sodium at least partly includes mixing a feedstock with a high content of potassium with a feedstock having a lower content of potassium and/or sodium.
(22) Said at least one liquid organic compound may be added as a single compound. However, in many embodiments according to the present invention said at least one liquid organic compound may comprise a range of organic compounds, and is preferably at least partly produced in situ in the process, and separated, recovered and recycled to said first step of pre-treating.
(23) According to a preferred embodiment said at least one liquid organic compounds is/are at least partly produced within the process, and separated or recovered and subsequently recycled to said first step of pre-treating. According to a preferred embodiment according to the present invention said one or more liquid compounds comprise a liquid hydrocarbon produced by the process such as a fraction of said liquid hydrocarbon product produced by the process e.g. the heaviest fraction of said liquid hydrocarbons produced as further described and exemplified below. Further said one or more liquid hydrocarbons may or may further comprise water soluble organic compounds produced in the process.
(24) In a preferred embodiment according to the present invention said at least one liquid organic compound being added in said pretreatment step comprises liquid hydrocarbon product produced by the process and/or a fraction of said liquid hydrocarbon product produced by the process such as the heaviest fraction of said hydrocarbon product.
(25) In another preferred embodiment according to the present invention said at least one liquid organic compound comprises or further comprises water soluble organics produced in the process and recovered from said residual fraction.
(26) In a preferred embodiment further comprising at least one liquid organic compound, the concentration of said at least one liquid organic compound contained in the feed mixture is at least 10% by weight, preferably at least 15% by weight, more preferred at least 20% by weight and even more preferred at least 25% by weight such as at least 30% by weight.
(27) Said one or more liquid organic compounds in the form of water soluble organics is according to the present invention present in a concentration of at least 1% by weight such as at least 2% by weight. In a preferred embodiment of the present invention said one or more organic compounds is present in a concentration of at least 5% by weight such as at least 10 or at least 20% by weight.
(28) In many applications, the concentration of said water soluble organics are in the range 2 to 40%, preferably in the range 5 to 35% such as in the range 5 to 20% by weight.
(29) In general the amount of liquid organic compounds required depends on the amount of carbonaceous material added and needs to be within a desired range to obtain the desired effects according to the present invention e.g. too much liquid organic compounds results in the content of other ingredients being with out the desired range. Hence, in a preferred embodiment of the present invention, the ratio of weight of said one or more liquid organic compounds to the dry weight of carbonaceous material in said feed mixture is in the range 0.1 to 2.0, preferably in the range 0.5-1.5, more preferred in the range 0.75-1.25.
(30) The texturing agent according to the present invention is adapted to be converted or degraded to same products as the carbonanceous during the hydrocarbon production process.
(31) The texturing agent may according to a preferred embodiment according to the present invention comprise micro algae, bacteria such as cyanobacteria; peat, palm oil manufacturers effluent (POME); residues, byproducts and waste from food production such as brewers spent grains and yeast; residues and byproducts from fruit and vegetable processing such as pulp; residues and byproducts from fermentation processes such as wet distillers grain, vinasse, molasses, black liquor from paper production, aerobic and anaerobic digested sludges e.g. sewage sludge from wastewater cleaning and/or digested sludge from biogasification and/or an off sepc Kraft pulp and/or a pulp of carbonaceous material prepared according to the present invention and/or a combination thereof.
(32) The texturing agent may according to many embodiments of the present invention be added in a concentration of 1-50% by weight of total dry matter content of said carbonaceous feedstock, preferably 2-50% by weight, more preferred 5-50% of total dry matter such as in the range 10 to 20% by weight.
(33) An advantageous embodiment of the present invention is where at least part of the carbonaceous material is used to produce a texturing agent in the form of a pulp such as a process for preparing a feed mixture for use in a process for producing hydrocarbon, comprising: a. Producing of texturing agent in the form of a pulp by i. Providing at least one feedstock of carbonaceous material; ii. Providing a desired water content; iii. Providing a desired content of homogeneous catalyst in the form of a compound of potassium and/or sodium; iv. Providing a desired content of liquid organic compounds v. Mixing the ingredients a) to c); vi. Controlling and adjusting the pH of the mixture to a pH in the range 10-14, preferably in the range 11-12.5 by addition of base; vii. Heating said pH adjusted mixture to a temperature in the range 150-230 C. under stirring to produce a texturing agent in the form of a pulp; b. Providing at least one feed stock of carbonaceous material; c. Providing a desired amount of water; d. Providing a desired content of homogeneous catalyst in the form of a compound of potassium and/or sodium; e. Providing a desired content of liquid organic compound f. Mixing the ingredients a) to e) for a time sufficient to provide a homogeneous feed mixture.
(34) The particle size of the carbonaceous material added for said pulping process according to i. may be significantly larger than the particle size of the materials the feed mixture. In an advantageous embodiment the maximum particle size of the material being added to said pupling process may be at least 10 times larger than the maximum particle size of said feed mixture such as at least 50 times larger than the maximum particle size of said feed mixture. Preferably the maximum particle size of the carbonaceous material being added to said pupling process may be at least 100 times larger than the maximum particle size of said feed mixture such as at least 500 times larger than the maximum particle size of said feed mixture.
(35) The ratio of the carbonaceous material being used in the pulping process (i.-vii) may to the total amount carbonaceous material generally be in the range 10-80% by weight such as 25 to 75% by weight, preferably the ratio of the carbonaceous material being used in the pulping process (i.-vii) may to the total amount carbonaceous material generally be in the range 33-66% by weight such as 40-60% by weight.
(36) During the production of the texturing agent by pulping the macrostructure of the carbonaceous material is broken down by reactions such as alkaline hydrolysis and solvolysis type of reaction. Hence, in many applications it is advantageous to add all the liquid organic compounds (steps iv.+e) and homogeneous catalyst (steps iii+d) and base (v) to said pulping process steps i. to vii.
(37) The pH adjustment may be performed by measuring and adjusting the pH by base addition. Suitable bases for pH adjustment according to the present invention includes sodium hydroxide, potassium hydroxide, potassium carbonate, sodium carbonate and/or ammonia.
(38) The conversion process of said feed mixture according to the present invention is advantageously carried out under alkaline conditions at all locations in the process i.e. the pH is maintained at a value above 7 such as a pH in the range 7 to 14, and preferably in the range 8 to 12 such as a pH value in the range 8 to 10 at all locations in the process. Operation under such alkaline conditions assists enhances certain chemical reactions such as water gas shift and steam cracking, while suppressing undesired side reactions such as char formation.
(39) Alkaline conditions during said conversion minimize corrosion.
(40) Hence, in many embodiment of the present invention the process of producing said feed mixture includes measuring and adjusting the pH of the feed mixture so as to obtain a pH value in the above preferred ranges.
(41) Hence, a preferred embodiment according to the present invention includes a process for preparing a feed mixture for use in a process for producing hydrocarbon, comprising: a. Producing of texturing agent in the form of a pulp by i. Providing at least one feedstock of carbonaceous material; ii. Providing a desired water content; iii. Providing a desired content of homogeneous catalyst in the form of a compound of potassium and/or sodium; iv. Providing a desired amount of water soluble organics v. Providing a desired amount of liquid organic compounds vi. Mixing the ingredients i. to iv.; vii. Adjusting the pH of the mixture to a pH in the range 10-14, preferably in the range 11-12.5 by addition of base; viii. Heating said pH adjusted mixture to a temperature in the range 150-230 C. under stirring to produce a texturing agent in the form of a pulp; b. Providing the desired amount of carbonaceous feedstock from at least one feed stock of carbonaceous material; c. Providing a desired amount of water; d. Providing a desired content of homogeneous catalyst in the form of a compound of potassium and/or sodium; e. Controlling and adjusting pH and buffer capacity of the feed mixture to control the pH f. Mixing the ingredients a) to g) for a time sufficient to provide a homogeneous feed mixture.
(42) The controlling and adjusting of pH and buffer capacity of the feed mixture may according to an embodiment of the present invention be performed measuring the pH of the water phase after the conversion process, and controlling the pH by adding a more or less base. The base for said addition may be the same potassium and/or sodium source as used for control of said at least one homogeneous catalyst, but may also be another base such as ammonia and/or urea.
(43) A particularly preferred embodiment according to the present invention is where the mixing of the mixture of the ingredients a) to g) and controlling the particle size is at least partly performed by withdrawing said feed mixture, passing it through a size reduction step such as a macerator and recirculating said feed mixture to the mixing device for a time sufficient to provide a homogeneous feed mixture.
(44) Hence, an advantageous process for preparing a feed mixture for use in a process for producing hydrocarbon according to the present invention, comprises: a. Producing of texturing agent in the form of a pulp by i. Providing at least one feedstock of carbonaceous material; ii. Providing a desired water content; iii. Providing a desired content of homogeneous catalyst in the form of a compound of potassium and/or sodium; iv. Providing a desired amount of water soluble organics v. Mixing the ingredients i. to iv.; vi. Adjusting the pH of the mixture to a pH in the range 10-14, preferably in the range 11-12.5 by addition of base; vii. Heating said pH adjusted mixture to a temperature in the range 150-230 C. under stirring to produce a texturing agent in the form of a pulp; b. Providing at least one feed stock of carbonaceous material; c. Providing a desired amount of water; d. Providing a desired content of homogeneous catalyst in the form of a compound of potassium and/or sodium; e. Providing a desired content of liquid organic compound f. Providing a desired amount of water soluble organics g. Adjusting pH of the feed mixture and buffer capacity of the feed mixture to control the pH h. Mixing mixture the ingredients a) to g) and controlling the particle size by withdrawing said feed mixture, passing it through a size reduction step such as a macerator and recirculating said feed mixture to the mixing device for a time sufficient to provide a homogeneous feed mixture.
(45) A particularly preferred mixing and size reduction technique according to the present invention is where the size reduction is according to an embodiment of the present invention where said maceration is performed as an integral part of a pump for pre-pressurizing said feed mixture such as a Gorator pump or double or multiple screw extruders.
(46) Hence, a particularly preferred embodiment is process for preparing a feed mixture for use in a process for producing hydrocarbon, comprising: a. Producing of texturing agent in the form of a pulp by i. Providing at least one feedstock of carbonaceous material; ii. Providing a desired water content; iii. Providing a desired content of homogeneous catalyst in the form of a compound of potassium and/or sodium; iv. Providing a desired amount of water soluble organics v. Mixing the ingredients i. to iv.; vi. Adjusting the pH of the mixture to a pH in the range 10-14, preferably in the range 11-12.5 by addition of base; vii. Heating said pH adjusted mixture to a temperature in the range 150-230 C. under stirring to produce a texturing agent in the form of a pulp; b. Providing at least one feed stock of carbonaceous material; c. Providing a desired amount of water; d. Providing a desired content of homogeneous catalyst in the form of a compound of potassium and/or sodium; e. Providing a desired content of liquid organic compound f. Providing a desired amount of water soluble organics g. Adjusting pH of the feed mixture and buffer capacity of the feed mixture to control the pH h. Mixing mixture the ingredients a) to g) and controlling the particle size by withdrawing said feed mixture, passing it through a size reduction step such as a macerator and recirculating said feed mixture to the mixing device for a time sufficient to provide a homogeneous feed mixture. i. where h. is performed using a Gorator type pump.
(47) A preferred texturing agent or additional texturing according to an embodiment of the present invention is chosen among the following: Hydrocolloids, polysaccharides, carboxymethylcellulose (CMC), methylcellulose, hydroxypropyl methylcellulose, microcrystalline cellulose (MCC), nanocrystalline cellulose (NCC), polyanionic cellulose (PAC), pectin, hydrocolloids such saccahrides such as carrageenan, pullulan, konjac and alginate, agar-agar, cassia gum, gellan gum, guar gum, locust bean gum and xanthan gum and combinations thereof.
(48) A particularly preferred texturing agent comprises a cellulotic material or a derivative of a cellulotic material such as selected from carboxy methyl cellulose (CMC), methyl cellulose, hydroxypropyl methyl cellulose, microcrystalline cellulose, nanocrystalline cellulose, polyanionic cellulose and combination thereof.
(49) Advantageously the texturing agent comprises a carboxy methyl cellulose (CMC).
(50) The molecular weight of said texturing agent is generally in the range 10000 to 1000000, preferably in the range 50000 to 750000, and the degree of polymerization is preferably in the range 100 to 5000.
(51) Advantageously the degree of substitution is in the range 0.5-1.5 such as in the in the range 0.60-1.0.
(52) In many embodiments according to the present invention the texturing agent or additional texturing agent is added in a concentration of 0.01 to 10% by weight, preferably in the range 0.02-5% by weight, more preferably 0.05 to 2 by weight, most preferably in the range 0.1 to 1% by weight.
(53) The mixing time for mixing said ingredients is generally in the range from 10 seconds to about 3 hours, such as from 1 minute to 2 hours. Preferably said mixing time is in the range 10 minutes to 1 hour.
(54) The feed mixture is withdrawn from the process of preparing said feed mixture and is converted by first pressurizing the feed mixture to an operating pressure for said conversion in the range 250 to 400 bar, and even more preferably in the range 275 bar to 350 bar such as in the range 300 to 350 bar. It should be understood that conversion process may comprise several of such processes for producing said feed mixture e.g. these subprocesses may be operated batch wise and feeding the continuous conversion process via a buffer tank.
(55) The pressurization may be performed in one or more steps. Suitable pumps for pressurization include positive displacement pumps such as reciprocating or rotary vane or gear pumps. Examples of preferred pumps include rotary lobe pumps, progressing cavity pumps, rotary gear pumps, piston pumps, screw pumps, vane pumps and diaphragm pumps.
(56) The pressurized and pre-treated feed mixture is subsequently heated to the reaction temperature for said conversion in one or more steps. The reaction temperature may according to an embodiment the present invention be in the range 280 to 450 C. such as in the range 330 to 430 C., preferably in the range 350 to 430 C. such as in the range 370 to 425 C., more preferred in the range 385 to 420 C. such as in the range 390 to 415 C.
(57) The heating is preferably at least partly performed by recovery of heat from one or more of the process streams to be cooled such as the hot raw product stream being withdrawn from said conversion step to maximize the thermal efficiency of the process. This may according to a preferred embodiment of the present invention be performed by direct heat exchange between the incoming feed mixture and the outgoing raw product stream as indicated in
(58) A further heating step using an external heat source is required to heat and trim the temperature of feed mixture to the desired operating temperature. This heating may be performed by direct heat exchange of the partly heated feed mixture with a heating fluid such as steam or with hot flue gas from a burner or furnace.
(59) In accordance with the invention the steam may comprise steam from an external process such as hot low pressure steam from a turbine. The steam may be further heated by an external heat source before heat exchange with the partly heated feed mixture to obtain specific heating rates and/or to minimize the heat transfer surface area required.
(60) In the embodiment of the present invention, wherein the heating fluid comprises hot flue gas from a burner, said burner may be a furnace comprising heat transfer surfaces for further heating said partly heated feed mixture or the hot gas may be transferred to an external heat exchanger for said heat exchange. In both cases it is greatly preferred that the fuel for said burner or furnace is at least partly comprised by combustible gases produced by the process. The co-combustion of such combustible gases produced by the process in said burner and/or furnace increases the overall thermal efficiency of the process and/or reduces waste streams from the process by destroying pollutants, whereby some objectives of the current invention are accomplished.
(61) In another advantageous embodiment in accordance with the present invention said further heating of the partly heated feed mixture to the desired operating temperature for said conversion may comprise indirect heat exchange with a heat transfer medium such as hot oil or a molten salt. External heat may at least partly be transferred to said heat transfer medium in a burner and/or furnace. Said burner may advantageously comprise co-combustion of gas produced in the process, and/or be equipped with means for recirculation of flue gas in a similar manner as described above.
(62) It is advantageous that said heating is not too slow and advantageously fast. Hence, in a particular preferred embodiment the heating rate in the temperature range 140 C. to 300 C. is preferably at least 50 C./min such as 75 C./min and preferably at least 100 C./min such as at least 150 C./min.
(63) The residence time for said conversion to proceed at the desired operating pressure and temperature may according to the present invention be in the range 1 to 60 minutes such as in the range 1 to 30 minutes, and preferably the residence time is in the range 1 to 25 minutes such as a residence time in the range 2 to 20 minutes, and even more preferably said residence time is in the range 3 to 15 minutes such as in the range 4 to 10 minutes.
(64) The process according to the present invention is preferably a continuous process, and may be performed in a substantially in a plug flow of the feed mixture. The flow velocities in pipes are according to an embodiment of the invention further selected so as to minimize sedimentation or precipitation of particles that may be suspended or formed during said conversion process e.g. by keeping at velocity in said pipes of at least 0.20 m/s such as at least 0.5 cm/s, and preferably in the range 0.2 to 5 m/s second such as 0.5 to 3 m/s.
(65) The residence time needed may according to the present be obtained by applying one or more long tubes preferably vertically arranged and connected with bends designed to minimize dead zones that could cause settlement. Flow velocities in said reactor tubes should preferably be maintained within the above ranges to minimize that the risk of sedimentation and clogging of said tubular plug flow reactor(s).
(66) Whereas embodiments of present invention typically allow for management of suspended particles without substantial sedimentation, precipitation or fouling even when processing feedstock having a high ash content, it may be beneficial to at least partly separate said particles from said fluid containing converted carbonaceous material while its hot, thereby e.g. reducing downstream separation needs. Suitable means for such particle separation include one or more gravimetric settling chambers, inline filters and/or hydrocyclones or combination thereof.
(67) Subsequent to said second step of converting the fluid comprising converted carbonaceous material is cooled to a temperature in the range 25 to 150 C. and expanded to a pressure in the range 1-25 bar in a third step of cooling and expanding. Said cooling is preferably performed by heat exchange with said incoming feed mixture in one or more steps as described above.
(68) The expansion in third step of cooling and expanding may be performed prior to a last step of cooling e.g. by cooling to a temperature in the range 100-200 C. such as 150 C. by direct heat exchange with the incoming feed mixture. This allows for a less expensive cooler for the last part of the cooling as this only requires operation at a pressure of 1-25 bar. A second step of said fluid comprising converted carbonaceous material may comprise cooling by preheating the feed mixture in said first step of preheating and/or for producing steam for export to e.g. an external process.
(69) The cooled and expanded fluid containing converted carbonaceous material from said third step of cooling and expanding is subsequently lead to a fourth step of separating from said mixture at least a residual fraction and a fraction comprising said liquid hydrocarbon.
(70) The fluid containing converted carbonaceous material may comprise liquid hydrocarbon product, a water phase containing water soluble organic compounds and salts, gas and suspended particles.
(71) According to a preferred embodiment of the present invention said fourth step of separating comprises means for separating gas from said mixture such as a degasser and/or a multiphase gravimetric separator equipped with means for withdrawal of gas and/or comprising different liquid outlets for withdrawing different liquid streams such as a liquid hydrocarbon rich phase and/or a water rich phase and/or particle rich stream.
(72) A preferred option comprises separation means for degassing and a at least coarse separation of said mixture into a liquid hydrocarbons rich stream and a residual fraction stream preferably after degassing. The gas from said degassing step is preferably fed to burner and/or furnace to supply heat to the process as described above.
(73) The means for separating may comprise or further comprise centrifugation such as by centrifugation in one or more disc centrifuge(s) and/or basket centrifuge(s) for separation of said liquid hydrocarbons and/or water and/or suspended.
(74)
(75) The oxidizing agent may according to the present invention be selected from oxygen, oxygen enriched air, air or hydrogen peroxide and may according to the present invention be added in an amount so as to convert up to 25% of the energy contained in said feed mixture to heat such as up to 15% of the energy contained in said feed mixture, and preferably the amount of said oxidizing agent being added is controlled to convert up to 10% of the energy contained in said feed mixture such as up to 5% of the energy contained in said feed mixture.
(76) The superheated supercritical fluid is in accordance with the present invention preferably at least partly generated within the process and reused. This may according to an embodiment of the present invention be performed by including one or more flashing steps during said third step cooling and expanding, condensing water from the vapour phase, and applying means for superheating and re-pressuring said vapour e.g. by superheating in an external furnace.
(77)
(78) The residual fraction according to the present invention comprises a water phase that may contain dissolved homogenous catalysts such as potassium and/or sodium. Whereas beneficial for the conversion the carbonaceous material such homogeneous catalysts are relatively expensive and may constitute a major operating cost. Further in many applications of the present invention between 10 to 30% of the energy may be contained in said carbonaceous material contained in said feed mixture is converted into water soluble organic compounds contained in said water phase. The presence of these liquid organic compounds in the water phase represent both a process loss reducing the thermal efficiency of the process, and put further requirements to purification of the water effluent from the process.
(79) An advantageous embodiment of the present invention include a fifth step of recovering comprising at least partly recovering homogenous catalyst in the form of potassium and/or sodium and/or liquid organic compounds from said water phase in a concentrated form (concentrate) and recycling said concentrate to said first step of pre-treating. Hence, such embodiment according to the present invention improves the process economy by reducing operating cost, improving energy efficiency of the overall process and increasing yield of said desired liquid hydrocarbons.
(80) A preferred fifth step of recovering in accordance with the present invention comprises concentration by an evaporation technique. Said evaporation may be performed in a falling or rising film evaporator and may comprise a multi-effect evaporator comprising 2 or more stages. It is further preferred that at least the first evaparator is equipped with means for vapour compression such as mechanical vapour recompression (MVR) and/or thermal vapour recompression (TVR) or a combination thereof. In a preferred embodiment steam for heating and/or thermal recompression such as by thermal recompression is produced by the process and thereby reducing the energy requirements for said evaporation and the overall thermal efficiency of the process. The distillate from the evaporation step may after condensation be further treated in an absorber using an alkaline scrubbing agent such as sodium hydroxide to control the amount of water soluble organics in the water effluent from the evaporation step.
(81) Many applications according to the present invention comprises concentrating water phase at least by a factor of 2 such as a concentration factor of at least 3 preferably said water phase is concentrated by at least a factor of 5 such as a concentration factor of at least 7 on a mass basis.
(82) The amount of liquid organic compounds recovered from said water phase (residual fraction) in said concentrate in said fifth step of recovering and being recycled to said feed stock is according to an embodiment at least 80% of the water soluble organics in the put stream to said fifth step of recovering measured as the concentration of total organic carbon present in input water phase. Preferably at least 85% of the water soluble organics in said water phase is recovered, and even more preferably the amount of liquid organic compounds recovered from said water phase is at least 90% such as at least 95%.
(83) Further the amount of homogenous catalyst in the form of potassium and/or sodium recovered from said water phase being fed to said fifth step of recovering is at least 90% such as at least 95% and preferably more than 99%.
(84) The last step of said evaporator in said fifth step of recovering is according to a preferred embodiment of the present invention further equipped with means for condensing said vapour phase from said last evaporator stage in two or more steps of condensing having a decreasing condensation temperature so as to condense compounds having a boiling point lower than water in said second or third step of condensing. Alternatively said compounds may be condensed in the same step as water by selecting the condensation temperature so as to condense such compounds. Said condensation temperature in said last step of condensing may be selected to have a condensation temperature of 40 to 60 C., so as to condense compounds having a boiling point lower than water, and at the same time minimize the mixing of these lower boiling liquid organic compounds with the evaporated water. Hereby it is not only obtained that said compounds having a boiling point lower than water is recovered and may be recycled to the process, but also that the evaporated water are cleaned to a level where it in many applications may be directly used e.g. for irrigation or discharged e.g. to sewer.
(85) The condensed water phase from said evaporation system according to the present invention may comprise organic compounds corresponding to a concentration of less than 0.01-5 g/l such as a TOC concentration of less than 0.1-2 g/l. The water phase may in many applications according to the present be clean enough for use as technical water internally or for irrigation purposes. Optionally a further polishing treatment may be performed.
(86) The concentrate from said evaporation contains liquid organic compounds in the form of water soluble organics in a concentration of at least to 10% by weight such as at least 40% by weight; preferably up the concentration of water soluble organics is at least 30% by weight such as at least 40% by weight. The majority of said concentrate is recycled to said feed mixture preparation step along with homogeneous catalyst contained in the concentrate.
(87)
(88) Depending on the specific feedstock, processing conditions and process configuration the liquid hydrocarbon fraction after said fourth step may comprise a crude oil, which may contain more or less water, more or less ash and salts, a relatively high acid number and/or high viscosity. The liquid hydrocarbon fraction may be of sufficient quality for direct use e.g. as a heavy fuel oil or coal substitute in industrial combustion applications. The liquid hydrocarbons may also be of sufficient quality for upgrading to transportation fuels like in a conventional large centralized refinery. However in many cases according to the present invention it is desirable to further upgrade the liquid hydrocarbon fraction so it has more and higher value direct applications.
(89) Hence an embodiment of the present invention comprises the steps and features described and further a sixth step of upgrading said hydrocarbon fraction by hydrotreating. Said sixth step of upgrading is preferably performed by heating said liquid hydrocarbon fraction to a temperature in the range 300 to 500 C. such as heating to a temperature in the range 330 to 420 C. and preferably to a temperature in the range 350 to 400 C. such as in the range 360 to 390 C. at a pressure in the range 10 to 200 bar and contacting said heated liquid hydrocarbon fraction with hydrogen gas over a heterogeneous hydrotreating catalyst such as CoMo, NiMo, NiW, Pd or Pt on a carrier of Y-alumina, aluminoslicates, zeolites (X, Y, or modenite), titania, or zirconia, thereby producing at least one upgraded liquid hydrocarbon fraction and at least one residue fraction and at least one gas fraction and at least one fraction comprising water. The liquid hydrocarbon fraction may in a preferred embodiment be separated such as by filtering and/or fractionation so as to separate particles, water and/or heavy residues from the liquid hydrocarbon fraction prior to said hydrotreating. Heavy residues in this context is meant to be compounds having a boiling point of at least 450 C. such as a boiling point of at least 500 C.
(90) The hydrogen gas for said hydrotreating may according to preferred embodiments of the present invention be at least partly produced by the process, and may comprise hydrocarbon gases such as C1-C6 hydrocarbons. A particularly preferred embodiment is where substantially all of said hydrogen gas is produced by the process.
(91) The fraction comprising water is according to a preferred embodiment recycled to the fifth step of recovering such as by introducing it into and mixing it with the residual fraction from said fourth step of separating.
EXAMPLES
Example 1
(92) A feed mixture was prepared by mixing 12.5 g of finely milled pellets from Aspen wood with 86.5 g of water and 1.0 g of potassium carbonate. The finely milled pellets from aspen wood was produced in a hammermill with a 250 micron screen. The finely milled pellets had a moisture content of 8.0% and an ash content of 0.4 wt %. The resulting slurry was transferred to a standard 50 ml syringe without needle (piston area approximately 1 cm.sup.2, outlet hole/syringe (approximately 1 mm.sup.2). The slurry could be squeezed out in a homogeneous stream without clogging when the piston was pressed directly after transfer to the syringe. The syringe was subsequently filled with the same feed mixture and the feed mixture was allowed to stand for 1 minute before pressing the pistion. Sedimentation of the feed mixture was visually observed before pressing the pistion. When pressing the piston the water was squeezed out of the feed mixture and a residual solid clog of dry matter that could not be pressed out of the syringe remained in the syringe.
Example 2
(93) A feed mixture was prepared by mixing 18.75 g of finely milled pellets from Aspen wood with 83.5 g of water and 1.5 g of potassium carbonate. The resulting slurry was transferred to a standard 50 ml syringe without needle (piston area approximately 1 cm.sup.2, outlet hole/syringe (approximately 1 mm.sup.2). When pressing the piston the water was squeezed out of the feed mixture and a residual solid clog of dry matter that could not be pressed out of the syringe remained in the syringe.
Example 3 15 Wt % Rape Seed Oil and Water Soluble Organics
(94) A feed mixture was prepared by mixing 18.75 g of finely milled pellets from Aspen wood, 15.0 g of rape seed oil, 65.75 g of water and 1.5 g of potassium carbonate. The resulting slurry was transferred to a standard 50 ml syringe without needle (piston area approximately 1 cm.sup.2, outlet hole/syringe (approximately 1 mm.sup.2). When pressing the piston the water was squeezed out of the feed mixture and a residual solid clog of dry matter that could not be pressed out of the syringe remained in the syringe.
Example 4 15 wt % with Recycle Oil
(95) A feed mixture was prepared by mixing 18.75 g of finely milled pellets from Aspen wood with 15.0 g of recycle oil and 50 g of water with water soluble organics produced from the same mixture in a high pressure process at 312 bar and 403 C., 13.45 g of demineralized water and 1.5 g of potassium carbonate. The resulting slurry was transferred to a standard 50 ml syringe without needle (piston area approximately 1 cm.sup.2, outlet hole/syringe (approximately 1 mm.sup.2). When pressing the piston the water the feed mixture flowed out of the syringe as a homogeneous mixture.
Example 4 20 wt % with Recycle Oil
(96) A feed mixture was prepared by mixing 25.0 kg of finely milled pellets from Aspen wood with 20.0 kg of recycle oil from a previous run and 42.24 kg of water with water soluble organics produced from the same mixture in a high pressure process at 312 bar and 403 C., 10.56 kg of demineralized water and 2.2 kg of potassium carbonate. The resulting slurry was transferred to a standard 50 ml syringe without needle (piston area approximately 1 cm.sup.2, outlet hole/syringe (approximately 1 mm.sup.2). When pressing the piston the water was squeezed out of the feed mixture and a residual solid clog of dry matter that could not be pressed out of the syringe remained in the syringe.
Example 5 20 Wt % with Guar Gum
(97) A feed mixture was prepared by mixing 25.0 kg of finely milled pellets from Aspen wood with 20.0 kg of recycle oil and 42.94 kg of water with water soluble organics produced from the same mixture in a high pressure process at 312 bar and 403 C., 2.2 kg of potassium carbonate, and 0.300 kg Guar gum premixed in 10.56 kg demineralized water. The resulting slurry was transferred to a standard 50 ml syringe without needle (piston area approximately 1 cm.sup.2, outlet hole/syringe (approximately 1 mm.sup.2). When pressing the piston the water the feed mixture flowed out of the syringe as a homogeneous mixture.
Example 6 Conversion of 20 wt % with Guar Gum
(98) The feed mixture described in example 5 was pressurized to 318 bar and heated to 410 C. in an induction heater before entering into the reactor. The residence time in the reactor was 10 minutes. The outlet temperature from the reactor was 388 C. The resulting product mixture was cooled, filtered and depressurized. The gas was separated from the remaining product and the remaining product was separated by gravimetric separation. After approximately 3 hours of operation a pressure drop started to build up over the reactor. After 5 hours of operation the pressure drop had increased to 10 bar and the feed was switched to water, the plant was shut down. The pressure drop was found to be caused by char formation in the reactor.
Example 7 27.5 Wt % Mixture of Peat and Wood
(99) A feed mixture was prepared by mixing 14.95 kg of finely milled pellets from Aspen wood (8% moisture) and 35.25 kg peat moss (61% moisture) with 27.5 kg of recycle oil and 15.0 kg of water with water soluble organics produced from the same mixture in a high pressure process at 312 bar and 403 C., 5.1 kg of demineralized water and 2.2 kg of potassium carbonate. The resulting slurry was transferred to a standard 50 ml syringe without needle (piston area approximately 1 cm.sup.2, outlet hole of syringe (approximately 1 mm.sup.2). When pressing the piston the water the feed mixture flowed out of the syringe as a homogeneous mixture.
Example 8 27.5 wt % Mixture of Peat and Wood with Guar Gum
(100) A feed mixture was prepared by mixing 15.0 kg of finely milled pellets from Aspen wood (8% moisture) and 35.0 kg peat moss (61% moisture) with 27.5 kg of recycle oil and 15.0 kg of water with water soluble organics produced from the same mixture in a high pressure process at 312 bar and 403 C., 2.2 kg of potassium carbonate and 0.3 kg guar gum premixed in 5.1 kg demineralized water. The resulting slurry was transferred to a standard 50 ml syringe without needle (piston area approximately 1 cm.sup.2, outlet hole of syringe (approximately 1 mm.sup.2). When pressing the piston the water the feed mixture flowed out of the syringe as a homogeneous mixture.
Example 9 20 Wt % with CMC
(101) A feed mixture was prepared by mixing 25.0 kg of finely milled pellets from Aspen wood with 20.0 kg of recycle oil and 43.0 kg of water with water soluble organics produced from the same mixture in a high pressure process at 312 bar and 403 C., 2.2 kg of potassium carbonate and 0.600 kg Caboxy Methyl Cellulose (CMC) premixed in 10.3 kg demineralized water. The resulting feed slurry was transferred to a standard 50 ml syringe without needle (piston area approximately 1 cm.sup.2, outlet hole of syringe (approximately 1 mm.sup.2). When pressing the piston the water the feed mixture flowed out of the syringe as a homogeneous mixture.
Example 10 Conversion of Feed Mixture with Wood & Peat
(102) The feed mixture described in example 7 was pressurized to 310 bar and heated to 398 C. in an induction heater before entering into the reactor. The residence time in the reactor was 10 minutes. The outlet temperature from the reactor was 383 C. The resulting product mixture was cooled, filtered and depressurized. The gas was separated from the remaining product and the remaining product was separated by gravimetric separation. The conversion process to liquid hydrocarbons was operated for 10 hours without any measurable pressure drop over the reactor.
Example 11 Conversion of Feed Mixture with Wood & Peat & Guar Gum
(103) The feed mixture described in example 8 was pressurized to 310 bar and heated to 396 C. in an induction heater before entering into the reactor. The residence time in the reactor was 10 minutes. The outlet temperature from the reactor was 382 C. The resulting product mixture was cooled, filtered and depressurized. The gas was separated from the remaining product and the remaining product was separated by gravimetric separation. After approximately 1.5 hours of operation a pressure drop started to build up over the reactor. The pressure drop was found to be caused by char formation in the reactor.
Example 12 Conversion of Feed Mixture Comprising 20 wt % Wood and CMC
(104) The feed mixture described in example 9 was pressurized to 314 bar and heated to 401 C. in an induction heater before entering into the reactor. The residence time in the reactor was 10 minutes. The outlet temperature from the reactor was 386 C. The resulting product mixture was cooled, filtered and depressurized. The gas was separated from the remaining product and the remaining product was separated by gravimetric separation. No measurable pressure drop was observed during 10 hours of operation.
Example 13 Conversion of Feed Mixtures Comprising 22.8 wt % Wood and CMC with Different Amount of Recycled Oil
(105) 100 kg of two feed mixtures was prepared. Both feed mixtures had 23.0% by weight (25 kg finely milled aspen wood as received), 0.6 wt % of CMC (0.6 kg) premixed in 10.3 kg demineralized water (reverse osmosis) and 2.2 wt % (2.2 kg) of potassium carbonate. Feed mixture A was prepared by adding 20.0 wt % of recycled oil (20.0 kg liquid hydrocarbon product) and 41.9 wt % (41.9 kg) of recycled water with water soluble organics and dissolved potassium homogeneous catalyst. Feed mixture B was prepared by adding 30.0 wt % of recycled oil (35.0 kg liquid hydrocarbon product) and 26.9 wt % (26.9 kg) of water with water soluble organics and dissolved potassium homogeneous catalysts from a previous run. Both feed mixtures were tested by the syringe test described above and both flowed out of the syringe as a homogeneous mixture.
(106) The feed mixtures were both converted in a continuous process by pressurizing to a pressure in the range 320-325 bars, and heating the feed mixture to a temperature in the range 402-409 C. Both feed mixtures resulted in an oil yield from the wood of approximately 42% (dry ash free oil yield from wood=Total dry ash free oil yieldTotal dry ash free oil added). However, whereas feed mixture A resulted in an oil which were fluidic and relatively low viscosity at room temperature, and a relatively low viscosity and fluidic oil, feed mixture B resulted in a thick, viscous oil at room temperature. This observation indicates that an optimum feed composition e.g. a certain amount of water is required for the desired reactions to proceed.