DE2943494A1 - METHOD FOR PRODUCING LIQUID HYDROCARBONS FROM COAL - Google Patents

Description

EAYER AKTIENGESELLSCHAFT
Central area

Patents, brands and licenses 5090 Leverkusen, Bayerwerk

Gai / MKI

28. Ok .. 1979

Process for the production of liquid hydrocarbons made of coal

It is known to convert ground coal by cracking pressure hydrogenation in the sump phase, optionally with addition of catalysts to be converted into distillable products and these in the gas phase over fixed catalysts to hydrogenate further.

rsbei is generally ground coal with a Mixture of smock oil and heavy oil rubbed. The ground Coal are added to catalysts if such substances are not already sufficiently present in the coal.

The coal pulp thus obtained is then pressurized together with hydrogen and / or circulating gas, heated and passed through one or more reaction spaces in which the so-called sump phase hydrogenation (1st hydrogenation stage) takes place. The products leaving the Sumpfphasehydrierung be performed in a somewhat below the reaction temperature held Keißabscheider, \: z a separation into a bottom product (blowdown) on one hand and there is gas and vapor products on the other. The sludge contains the heaviest oil fractions, asphalt, unreacted coal particles and possibly other solids. The sludge can, for example, be thickened (topped) in a flash evaporation with a subsequent variable stage, for example to a solids content (insoluble in benzene) of approx. 40 to 60%.

The resulting distillate oil can be used to grind the

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Coal can be used. The topped sludge can be partially oxidized in the presence of water vapor at 1100 up to 1500 C to a mixture of carbon oxides and water vapor gasified, which can be worked up to hydrogen.

The gaseous and vaporous ones leaving the hot separator Products are grounded in heat exchangers against incoming coal dust and then cooled to near room temperature in a final cooling and fed to a scraper, 77ο the separation into liquid and gaseous products takes place and the gaseous products are returned as cycle gas. The liquid products will be on Relieved normal pressure and, after separation of the aqueous phase, subjected to a distillation at normal pressure,

5Where gasoline, medium oil, and heavy oil can be obtained.

Ground part of the heavy oil and part of the medium oil each generally used to grind the coal. The remaining parts and the gasoline that together make up the oil profit are generally solid in the gas phase arranged catalysts further hydrogenated.

It has been now found a process for the production of liquid hydrocarbons from coal found by cleaving hydrogenation under pressure, in which ground coal, optionally together with catalysts with a / out in the 'itself resulting mixture bus mean ol and heavy oil and the Kchiebrei thus obtained anreibt together with Hydrogen heats up under pressure and passes through one or more ReakTionsräuine, leads the reaction products into a hot separator kept slightly below the reaction temperature, the bottom product from the hot separator separates into a distillate oil for grinding the coal and a residue that is converted into synthesis gas, and

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the gases and vapors drawn off at the head of the hot separator, if necessary via a second hot separator conducts and then cools in series-connected heat exchangers, which is characterized in that the condensates occurring between and behind the heat exchangers are collected in wipers from these condensates a share for the grind oil and a share as oil profit withdraws and both parts without intervening distillation to grind carbon or the hydrogenation in supplies the gas phase or mixed phase.

In this process, the coal pulp can be produced, for example, by grinding the practically asphalt-free medium and heavy oils in the coal: oil ratio of 1: 1 to 1: 3. Suitable catalysts are, for example, mixtures containing iron compounds, such as Bayer mass or Lux mass (the latter also in used form), iron ores or iron salts. Bayer mass ¹ CZW. Lux masses are the residues that occur when bauxite is broken down with sodium hydroxide solution or soda, for example 48.6 % Fe ₃ O ₃ , 20 % AlpO ₅ , 9.2% SiO ₂ , 5.0 % TiO ₂ , 0.2% MnO ₂ , 1.2% CaO, 0.5% MgO, 6.2 % Na ₃ O, 0.2 % K _? 0 and 13 to 15 % H ₃ O (see Ullmann, Enzyklopadie der Technischen Chemie, Volume 10, page 499 (958)). An example of the iron salt is ferrous sulfate ir.i'rage, which occurs in aqueous solution the coal can be soaked up. The catalysts can be added, for example, in amounts of 0.5 to 5.0% by weight, based on the anhydrous and ash-free coal (pure coal) used. If the coal already contains such catalyst components, the addition of catalysts to the coal pulp can also be omitted.

The coal used for the process according to the invention is, for example, a wide variety of hard or lignite coals

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Annex to the submission dated December 4 , 1979, L.

Suitable for mining areas. Lignite is preferably used together with a catalyst.

The coal pulp is pressurized together with hydrogen, which generally consists of fresh hydrogen and cycle gas. For example, pressures in the range from 100 to 400 bar are suitable. The heating of coal pulp and hydrogen can take place ^{to 380 to 420 0 G, for example.} The reaction space or the fieaictiünsräume for the hydrogenation in the Sumpi ¹ phase can be, for example, maintained at 420 and 490 ⁰ C.

The reaction products from the sump phase hydrogenation are fed to a hot separator which is kept at a temperature a little below the temperature of the sump phase hydrogenation, for example 10 to 50 ^° C. below the temperature of the sump phase hydrogenation. The sludge separated in the hot separator can be processed further using known methods. For example, a distillate can be obtained from it by expansion evaporation with a downstream vacuum stage, which can be used (also) for grinding the coal, and a topped blowdown which is suitable for hydrogen production.

The first, above-described hot separator, a second hot separator can be followed by, optionally, can be operated less to 30 ⁰ C, for example, 10 than the first hot separator. In the second hot separator, small amounts of solids and asphaltenes that are entrained can be separated off. The substances separated in the second hot separator are generally added to the sludge from the first hot separator.

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The gases and vapors present after the hot separator (s) are grounded in heat exchangers connected in series chilled. It is an essential feature of the method according to the invention that the between and collects condensate in wipers behind the heat exchangers. For example, you can have 3 or more Use heat exchanger.

The heat exchangers can be operated, for example, in such a way that a heat exchange takes place in the first heat exchangers or the first heat exchanger between the gases and vapors from the hot separator (s) on the one hand and the carbon pulp and / or the circulating gas used in the first hydrogenation stage on the other hand. The last ¹ heat exchanger or heat exchangers are preferably operated with water or air as the coolant. Two heat exchangers are preferably used for the heat exchange between the outgoing gases and vapors and the incoming raw materials, coal pulp and cycle gas, and one or more air and / or water coolers in the further cooling path.

Zv.-i see or after individual or all heat exchangers the condensates that occur are separated off, for example in wipers.

The heat exchangers are preferably operated and the separation of the condensates carried out so that one collects at least three different condensates. Preferred option one works in such a way that a heavy oil condensate, which boils essentially above 325 ° C, a middle oil, densat, that essentially boils between 180 and 325 ° C and a gasoline condensate that essentially boils between 30 and 180 ° C, collects. Of course, it is also possible to use more than the three aforementioned Separate condensates, for example two heavy oil condensates, two medium oil condensates and / or two gasoline

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condensates. The boiling ranges given above for individual condensates relate to normal pressure and represent guide values, from which there are also major deviations are raw.

The gssförr.igen fractions which remain after the condensates have been separated off and which contain substantial amounts of hydrogen are preferably returned as cycle gas before the sump phase hydrogenation. Water occurs almost exclusively in the gasoline condensate, where it separates out as the lower insoluble phase and can be drawn off separately from the hydrocarbon phase. If necessary, the aqueous phase can also be separated off in a downstream settling tank. The regulation of the boiling limits of the condensates can be done in different ways. For example, the boiling limits of the condensates can be influenced by the design of the heat exchangers. Furthermore, the separated, high-boiling and still hot condensates or parts thereof, for example the heavy oil condensate, can be cooled by heat exchange for hydrogen and the hydrogen heated in this way can be fed to the cooking paste in quantities that are tailored to the requirements, for example before the first heat exchanger cdar passes the first heat exchanger. Preferably, that portion of the heavy oil condensate that is returned to grind the coal is used for heating the cycle gas.

The selectivity between the individual condensates can be increased if the condensates are in separators separated and then individually cooled in reflux condensers against circulating gas. If the heat exchange between the heavy oil condensate or parts thereof and the cycle gas the heavy oil condensate or parts of it for the further Not yet used, e.g. as a grinding oil for the charcoal

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has cooled sufficiently, the heavy oil condensate or parts thereof can be further cooled, for example by air cooling will.

The heavy oil and middle oil condensates obtained as described above are generally taken from provided quantities of oil. The remaining parts of the heavy oil and medium oil condensate are together with The gasoline condensate is available as oil for further processing. The oil gain can be made without significant pressure relief and lowering the temperature of the hydrogenation in cc-r gas phase or mixed phase. in the In general, the combined oil gain will be used as a whole in the further hydrogenation. Should this under aromatizing hydrogenation conditions are operated, it is advantageous to refine the gasoline condensate separately to hydrate.

In special cases it can be advantageous to pressurize individual condensates, in particular the gasoline condensate, to normal pressure to relax and thus to degas.

The hydrogenation in the gas phase or mixed phase (second hydrogenation stage) is preferably carried out over fixed catalysts carried out. This hydrogenation can be carried out, for example, at 100 to 400 bar and as a refined hydrogenation at 3 ^ 0 to 420 C or as a splitting hydrogenation 420 to 480 C can be carried out.

Suitable catalysts for the second hydrogenation stage are, for example, oxides, sulfides or phosphates of the metals of VI. or VIII. Group of the periodic table, such as tungsten or molybdenum, optionally mixed with

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Attachment to the entry of 4.12.79 '// (T- ■ - "..,"'

Oxides or sulfides of the iron group, expediently applied to supports such as aluminum oxide and its spinels, natural or synthetic bleaching earths ", in particular zeolites. Platinum and rhenium are also suitable as hydrogenation catalysts. Highly active catalysts are preferably used in this hydrogenation, for example nickel / tungsten sulfide on vehicles. in order to obtain such catalysts, the high activity for extended periods, a certain HPS partial pressure is during this hydrogenation needed. the use of products should therefore in the hydrogenation of a sulfur content in the order of about 0.1 have to 1%. one such The sulfur content can optionally also be maintained by adding sulfur or sulfur compounds.

The reaction products from this hydrogenation can be worked up in a customary manner, in particular by breaking it down into the desired fractions by distillation at normal pressure. The products consist of Hydrogen-rich hydrocarbons free of secondary components such as oxygen, nitrogen or sulfur compounds. They can be used as finished products, but are also fully suitable for use in further processing in the usual processes in the petroleum industry, such as catalytic cracking and reforming, hydrocracking, thermal and. pyrolytic cracking.

The main advantages of the process according to the invention are that, after the first hydrogenation stage, the Distillation of the condensed gases and vapors, carried out according to the prior art at normal pressure is avoided. In addition, pumping can be performed on reaction

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pressure for those fractions from the first hydrogenation stage that are used in the second hydrogenation stage are omitted will. Inden the heavy oil and middle oil condensates while still hot in the hydrogenation with a fixed catalyst are introduced, there are significant energy savings when heating to the reaction temperature. It should also be mentioned that after the sump phase hydrogenation if the gasoline condensate is produced separately, the aqueous phase is separated off because of the greater differences in density is much easier than with the single-stage condensation of the condensable products the gases and vapors of the hot separator.

When using lignite, after the gas phase hydrogenation Products are obtained that are practically free of nitrogen, oxygen and sulfur and at which the gasoline fraction over 13.4, the medium oil fraction over 12.6 and the heavy oil fraction over 11.8 wt .-? S "Contain hydrogen. Such products are particularly suitable for pyrolytic cracking for manufacture of basic chemicals, mainly olefins and Ar ο ma'c er ..

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example

106.5 t of dried Rhenish lignite, corresponding to 100.0 t of pure coal (anhydrous and ash-free) are mixed with 3 t of Eayer mass of the composition 43.6% Fe-O ^, 20 % AlpO ,, 9.2? I SiOp, 6, 0 % TiO ₂ , C, 2 ° i MnO _p> 1.2 JS CaO, 0.5 % MgO, 6.2 # Na ₂ O, 0.2 # K ₂ O and 13-15 % H ₂ O added and with 150 t of oil from the first hydrogenation stage, consisting of 20 t of vacuum distillate (from the final distillation), 45.1 t of medium oil condensate and 84 t of heavy oil condensate, ground to a coal pulp. The coal slurry is .gebracht to the operating pressure of 300 bar and heated together with fresh hydrogen and recycle gas heat exchanger, and a preheater to 430 ⁰ C and introduced into the first hydrogenation reactor, where the hydrogenation at 470 C is carried out under Wassersxoffaufnahme of 4.5 t. The reaction products pass from the reactor into a hot separator kept at 435 ° C, where they are separated into a sump phase product (blowdown) on the one hand, which is converted into vacuum distillate and topped blowdown by flash evaporation, and the gases and vapors drawn off from the upper part, which give off part of their latent arms in two heat exchangers connected in series to the incoming mixture of oil pulp, circulating gas and fresh hydrogen. In the first heat exchanger, the gases and vapors are cooled to 350 ° C, with 96.2 t of heavy oil condensing, which is taken up in a first scraper. In a second heat exchanger, the cooling to 225 ° C takes place, with 72.3 t of medium oil condensing, which is taken up in a second scraper. In the final cooling, the temperature is lowered to 40 ** Ό, with 7.5 "t gasoline condensing, which is picked up in a third scraper. In addition, 10 t gaseous hydrocarbon

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substances C ^ to C ,. 84 t of the heavy oil condensate are removed and, after cooling in a heat exchanger against circulating gas and subsequent air cooling to normal pressure, expanded and used as part of the grinding oil. 45.1 t of the middle oil condensate are used as a grinding oil component after cooling and relaxation. As oil gain • the following are withdrawn from the three scrapers: 12.2 t heavy oil, 27.2 t medium oil and 7.5 t gasoline and fed to the second hydrogenation stage with a fixed catalyst without pressure relief or temperature reduction. The hydrogenation of the combined oil profit (46.9 t) in the second hydrogenation stage is carried out in the hydrogen cycle gas at 42O ⁰ C and 290 bar on nickel / tungsten sulfide on alumina t under a hydrogen uptake of 1.6. After cooling to 40 ⁰ C and separation of the recycle gas in a further squealer are obtained: 12.1 t gasoline, 21,7 t middle oil and heavy oil 10.7 t.

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Claims (7)

Patent claims: 1) Process for the production of liquid hydrocarbons from coal by splitting pressure hydrogenation, in which ground coal, optionally together with catalysts, with a mixture of medium oil and heavy oil that occurs during the process itself, and so on The resulting coal pulp is heated together with hydrogen under pressure and passes through one or more reaction spaces, the reaction products in a slightly below The hot separator maintained at the reaction temperature leads the bottom product out of the hot separator separates into a distillate oil for grinding the coal and a residue, which is converted into synthesis gas, and the ac head of the hot separator extracting gases and If necessary, conducts vapors through a second heat separator and then in series-connected heat exchangers cools, characterized in that the 2v.'ischen and occurring behind the heat exchangers Collects condensate in wipers, from these condensates: a part for the grinding oil and a part 2C ^£ ls subtracts oil gain and supplies both parts without intermediate distillation for grinding coal or hydrogenation in the gas phase or mixed phase. 2) Method according to claim 1, characterized in that at least 3 different condensates are collected. Le A 19 969 130019/0385 ι- 3) Method according to claim 1 and 2, characterized in that a Schv / erölkondens-t which ^{boils substantially above 325 0} C, a middle oil condensate which boils substantially between 180 and 325 C and a gasoline condensate which is essentially Boils in the range between 30 and -180 C, collects. 4) Method according to claim 3, characterized in that the hot heavy oil condensate in heat exchange cooled against hydrogen and the thus heated hydrogen is fed to the coal pulp. 5) Method according to claim 1 to 4, characterized in that the withdrawn oil gain without substantial Relieving pressure and lowering the temperature supplies the hydrogenation in the gas phase or mixed phase. 6) Process according to claim 1 to 5, characterized in that the hydrogenation is carried out in the gas phase or mixed phase carried out on fixed catalytic converters. 7) Method according to claim 6, characterized in that that the catalyst is a highly active hydrogenation catalyst, the activity of which is optionally achieved by adding Maintain sulfur or sulfur compounds will. Le A 19 969 130019/0385