DE3028648A1 - METHOD FOR CONVERTING COAL TO GASEOUS HYDROCARBONS AND VOLATILE DISTILLATES - Google Patents

Description

Dr. Dieter Weber Klaus Seiffert

3028641

Godfather

I) Ip) -I 'ham. Dr. Dieter Weber · nipI.-Phyn. Claw SelXfert ΡοβΙΓημΙι ΙΙΙ4Π U2ÜO Wiesbaden

D-6200 Wiesbaden 1

f 26

Telephone 06121/872? 20 Telegram resee t Willpatent Τθ1θχι-4-1ΘΘ247

Po steche ale ι Frankfurt / Main βΤ68-βΟ2 Bank: Dreedner Bank AG, Wiesbaden, Account No. 276ΘΟ7 (sort code 610810060)

July 28, 1980 36266/36241

Chemroll Enterprises, Inc., 100 Wall Street,

New York, New York 10005 / USA

Process for converting coal into gaseous hydrocarbons and volatile distillates

Priority: USA - Ser. No. 063 824 of Aug. 6, 1979 U.S. - Ser. No. 114 207 of January 22, 1980

3 0013/0393

The present invention relates to a method of making various useful fabrics, principally gaseous substances from coal or peat and for converting djeser gaseous substances in different distillates. In particular be = The invention draws on the conversion of coal or Οίο rf into desired conversion products such as liquid or gaseous hydrocarbons by converting coal or peat mat one special reagent in the presence of water, steam and / or hydrogen at low to moderately elevated temperatures and at atmospheric pressure.

The invention further relates to the conversion of Using a special reagent, coal is divided into various pre-selected fractions, essentially gaseous components, the carbon being converted into useful degradation products in the presence of this reagent, by water, water vapor and / or hydrogen will. These breakdown products are mainly gaseous hydrocarbons, which are used for the production of liquid distillates can be traced back. Ultimately, at the high temperatures, the carbon in the presence of the reagent and of Water vapor also creates some hydrogen. The resulting residue contains ash from the coal and reagent and can be recovered of the reagent, which can then be reused.

It became more and more evident that the deposits of liquid and gaseous hydrocarbons such as oil deposits and natural gas reservoirs are being depleted so rapidly that strong efforts must be made to reduce the To be able to meet the expected future demand for energy and raw materials for the chemical industry and a corresponding one To create a replacement. One of the most readily available sources of hydrocarbons is coal, but there have not been any Opportunities from coal without substantial capital investment. Hydrocarbons in an economically feasible manner to manufacture. While there are different methods of converting

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BATH ORIGINAL

of coal at a high temperature of, for example, above 600 ^° C. and high pressure of, for example, more than 25 bar, known as coal gasification process, but currently there is no. Process for converting coal to hydrocarbons is available, which can be carried out at low temperature and low pressure.

In connection with the present invention, the applicant has US Patents 3,926,775, 3,933,475, 3,944,480, 3,960,513, 3 957 503, 4 018 572, 4 030 893, 4 057 422 and 4 078 917 are known.

It has been found that charcoal when treated with a special reagent in the presence of water vapor into various hydrocarbon fractions, mainly gaseous Hydrocarbons with 1 to 5 carbon atoms such as methane, ethane, Athens, etc. can be converted.

It was further found that this conversion was carried out at different temperatures, i.e. by using steam and coal in defined process steps, the quantitative ratio of the various hydrocarbons obtained from the coal is changed, and at low temperatures volatile liquid hydrocarbons and, at high temperatures, mainly gaseous hydrocarbons are formed.

It was also found that various coals, u.zw. Lignites of various compositions and sub-bituminous coal (black lignite), produce products of various types at the start of distillation, although always both liquid and gaseous Hydrocarbons are formed. Higher quality coals produce more liquid hydrocarbons than lower quality coals Coals under given reaction conditions, but it is possible by changing the working conditions or the reagent to increase the amount of liquid hydrocarbons. It is believed that when an alcoholic solution of KHS or such an additional sulfur-containing solution to form coal, a conversion according to the equation

KHS + S ₂ > 1/2 H ₂ S + 1 / K ₂ S ₅

expires. It follows that KHS can be used without the addition of sulfur, but KHS is given shape by sulfur a polysulfide stabilized to a lesser extent hydrolyzed

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sated. In the presence of water, KHS is partially converted into K ^ S, which is why both KHS and K ₂ S should be available for the conversion. If sulfur is added to Palis, the result is to a lesser extent hydrolysing and therefore more water-resistant polysulphide.

The reaction equation given above for KHS also applies to KaHS, which apparently does not contain elemental sulfur allows you to work better.

It is also possible KHS or NaHS in dry form, that is without adding any alcohol. NaHS is manufactured industrially and in the cone in the form of scales with a Water content of about 30 wt .- # supplied.

When K ^ S and various potassium polysulphides reacted with charcoal the oxygen, sulfur and nitrogen bound in the coal and the coal are preferably attacked withdrawn. When the coal is in the presence of water vapor or water oxygen, nitrogen and sulfur in various forms Compounds are removed, there is the possibility in the coal where oxygen, nitrogen and sulfur are split off introduced hydrogen and thus hydroaromatic, aromatic and shorter-chain aliphatic compounds to build.

It has been shown that there must be oxygen in the coal. Because of this, inferior coals are like lignite extremely suitable. As the quality of the coal increases, for example with sub-bituminous coal (black lignite), the oxygen content of the coal decreases, which is why a smaller amount of gaseous flow products and a larger amount of liquid sales products is obtained. It has shown, that even sub-lignites and peat are processed into various hydrocarbons by the process according to the invention can.

For the purpose of explaining the invention, reference is made to the drawing, the figure of which is a schematic diagram of a system for performing it of the process according to the invention and for separating off the products of the process.

In the system shown in the figure, the reaction vessel 11 is a retort or the like. Device to which finely ground coal is fed. In the case of lignite, the particle size is up to 6.55 mm, but the particle size can also be larger, since the conversion is independent of the grain size of the coal. In the case of sub-bituminous coal, the particle size can be up to 6.35 mm, but the particle size is preferably about 0.79 mm "S or KHS (or equivalent thereof) in an alkanol supplied closed and the system and the temperature is raised to 65 ⁰ C, at which temperature the reagent is distilled off the alkanol. Since the reaction mixture is stirred by the inert gas supplied, for example nitrogen or hydrogen, water is also given off together with the alkanol. As a rule, methanol or ethanol is used as the alkanol, but higher alcohols, the alkanols with up to four carbon atoms, can also be used.

As soon as the desired working temperature has been reached (after the alkanol used has been distilled off), steam is fed to the system at a suitable temperature so that the inert gas such as nitrogen that is initially used to remove the oxygen from the system is no longer necessarily passed through the system got to. The steam boiler 12 is equipped with a device for heating the water contained therein, but auxiliary heating, for example for heating the line leading from the steam boiler VI to the reaction vessel 11, can also be provided.

Suitable devices for monitoring and regulating the reaction taking place in the reaction vessel, e.g. heating coils, Cooling coils, temperature sensors, heat regulators, stirring devices etc. can be provided. The reaction vessel can if desired, they can also be heated from the outside.

£) 01

_ 11-

The reaction products flowing out of the reaction vessel pass into a cooler 13, which is in the manner of a
Reflux condenser can be formed, in which the inlet temperature and the outlet temperature of the cooling water is adjusted so that the heavy fraction from the coal
Condense coming fraction products first. The heavy fraction can condense on the walls of the condenser insert 13a and then down "into the collecting container 14
flow and are withdrawn from there, processed and occasionally also analyzed.

The products flowing out of the collecting container 14 in gaseous form are fed to a second condenser 15, where they are cooled and finally passed through a series of washers to which suitable washing liquids are fed
achieve that in each of the washing liquids the desired
Fraction is enriched in reaction products. When working on an industrial scale, one might like fractionation in one
Distillation column be cheaper.

The gaseous reaction products which have not gone into solution and which have not been washed are passed into the next washer, in which further reaction products are separated off in a manner to be explained later. Although seven washers are shown in the drawing, the number of washers depends on the
Number of gaseous fractions to be separated off. Accordingly, a larger or smaller number of washers can be provided. The amount of the finally remaining gaseous fraction is measured in the gas meter 17 and can be collected and further processed, for example washed again and purified, for example by distillation, or directly
can be reused.

Since the gaseous fraction obtained in the gasification of coals according to the invention is a narrow fraction consisting largely of hydrocarbons with 1 to 6 carbon atoms
this fraction can also be separated by fractionation into the individual components, some of which are close to the liquid state of aggregation. Suitable fractionation

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directions are, for example, distillation columns and Molecular sieves. Such fractionation devices, for example Distillation devices are sufficiently known to the person skilled in the art and do not need to be explained in more detail.

For the present purpose, however, there is a possibility described, which allows different fractions due to the different solubility of hydrocarbons with 1 to 6 carbon atoms to separate into their components.

This process can be carried out continuously. The separation of the individual reactants (for example the reagent containing an alcohol) can, for example can be made so that the system is continuously supplied with the reagent, charcoal and steam and is operated with continuous removal of the reaction products. Under these conditions, under certain circumstances flushing with inert gas can be dispensed with. The dissolved constituent can be separated from each of the washers 16 the washing liquid used therein is also separated off.

The given below solubility of the suitable gases are given for a temperature of 22.22 ⁰ C, so for room temperature, because the different scrubber at room temperature and can be operated near atmospheric pressure and, accordingly, the solubilities are interesting at this temperature. It should be noted that higher pressures, for example in a distillation plant, can also be maintained in order to avoid working at excessively low temperatures. If the pressure conditions are changed, the output can be estimated or calculated by a person skilled in the art of distillation technology when the pressures are changed.

Known solubilities of hydrocarbons withdrawn from the system, u.zw. the solubilities of hydrocarbons with 1 to 6 carbon atoms are the following:

Athens is soluble in ether, somewhat soluble in alcohol,

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Acetone and benzene and insoluble in water. Ethane is soluble in benzene, somewhat soluble in alcohol and acetone, and insoluble in water. Propane is soluble in water and alcohol, very well soluble in ether and benzene and slightly soluble in acetone but also very easily soluble in chloroform. Propene is very good soluble in water, alcohol and acetic acid. Butane is very soluble in alcohol, ether and chloroform and is soluble in water. 1-butene and 2-butene are very soluble in alcohol and ether, soluble in benzene and insoluble in water. 1-pentene, Pent-2-en and trans-pentene can be mixed with alcohol and ether, very easily soluble in dilute sulfuric acid, soluble in Benzene and insoluble in water. Pentane is miscible and slightly soluble with alcohol, ether, acetone, benzene, chloroform and heptane in water. Hexane is soluble in ether and chloroform, very soluble in alcohol and insoluble in water. Hex-1-en, Hex-2-en, hex-3-en and trans-hexene are soluble in alcohol, Ether, benzene, chloroform, petroleum ether, but insoluble in water. Methane is soluble in water, alcohol, ether, benzene, Methanol and Toliiol and somewhat soluble in acetone.

The reagent, for example potassium hydrosulphide or sodium triumhydrοsulphide or a polysulphide of these alkali metals, is regenerated in one of the reaction vessels if KOH or NaOH dissolved in an alkenol is used there as washing liquid and this is reacted with a corresponding amount of ^ S. Under these conditions, the reagent is precipitated in the form of a white precipitate, for example in the form of K ₂ S (hydrate) or NaAS (hydrate). The alkali metal sulfide is only slightly soluble in ethanol or higher alkanols, which is why the precipitated alkali metal sulfide can be removed from the system simply by removing the precipitate from the scrubber.

The ash remaining in the reaction vessel 11 is removed from the Reaction vessel removed in a suitable manner and worked up, for example the soluble ones contained in the ash Substances are dissolved and, for example, potassium on the basis of different solubilities of calcium hydroxide and potassium

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hydroxide is extracted, that is, when extracting potassium with calcium hydroxide, calcium sulfate is precipitated and potassium hydroxide can be separated off. Sodium hydroxide is contained in the ash and, as is known per se, can be removed therefrom in the same way or in a different way. Since sodium is contained in coals in much smaller amounts than potassium, it may be necessary to supplement sodium when the process is carried out continuously If a keagent based on sodium is used. Potassium is present in sufficient quantity in the coal. As can be seen from the above, a hydrocarbon reaction is obtained at low temperatures in the reaction of a lignite of the type given, for example, in the following example, which hydrocarbons with Contains 3 to 6 C atoms and on average mainly contains hydrocarbons with 4 C atoms. This fraction is generally worked up at temperatures up to about 120 C. At 220 ^° C., a fraction containing methane to butane and also corresponding unsaturated hydrocarbons is formed At 360 to 450 ^° C. essentially A is produced then and possibly some hydrogen. In order to ensure that no hydrogen sulfide is lost, the outflowing products are washed with a saturated alkanolic solution of an alkali metal hydroxide, for example potassium hydroxide or sodium hydroxide, the hydrogen sulfide reacting with the alkali metal hydroxide to form the corresponding alkali metal sulfide, in the selected example to form KS and Na ^ S, which reacts in The presence of water also regresses KHS and NaHS. The gas stream washed in this way only contains hydrogen sulfide in a very small amount, for example in an amount of less than 0.01%.

The method explained above is explained in more detail below by examples that do not restrict the subject matter of the invention.

Example 1: 50 ml of a methanolic solution of potassium hydrosulfide, which contains 0.37 g potassium hydrosulphide per ml, were used as the original keagent. There were 71 g

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processed a lignite which, based on ashless dry matter, contained 66 ^C J> C, 3.97 # H, 18.2 # O and 0.9 ^ N and also a small amount of volatile substances. The raw lignite contained 33 wt% water and 9 wt% ash. The ash content of the lignite delivered moist was 6% by weight. The lignite contained 0.69 wt -. "/> Organically bound sulfur, however, the content of the lignite of pyrite sulfur was unknown.

The Versucte were carried out with 2 hours at 135 ⁰ C dried lignite and lignite not dried. The fundamental difference between dry lignite and moist lignite was that the moist lignite produced very light hydrocarbons at temperatures below the boiling point of water as the reaction temperature increased. The water contained in the lignite provided the hydrogen for the resulting hydrocarbons. In other respects the implementation proceeds in the same way.

Elemental sulfur has been added to the lignite, but the sulfur can also be added to the alcoholic solution from KHS will. The total amount of sulfur was 8.25 g including the organically bound sulfur in the lignite.

According to the figure in the drawing, the device consisted of a container and a supply line for inert flushing gas, for example hydrogen or nitrogen. These inert gases can be introduced into the reaction vessel 11 directly or into the reaction vessel 11 via a steam generator and a steam line. The steam line was ^{heated to HO 0} C and opened into the reaction vessel, which was heated to the same temperature, near the bottom thereof.

Temperature measuring devices were also provided. In As a rule, the steam line opens through the central opening of a piston serving as a reaction vessel. Initially it was the reaction mixture was stirred by the nitrogen or the hydrogen, the methanol distilling off the reagent solution. The reaction mixture can also be mixed in another way, for example by stirring. That in the raw

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Water present in lignite is created during! Distillation a gaseous hydrocarbon soluble in methanol or ethanol.

When using dry lignite, the formation of such a liquid hydrocarbon is minimized pushed back. The reaction vessel 11 can be any have a suitable shape, but in this experiment one was equipped with a suitable feed nozzle on its top Round bottom flask used.

Another feed nozzle is used to feed in lignite and also as a discharge opening. The reagent is over a during of the experiment closed opening supplied.

Another connection leads to a vertically arranged condenser charged with water as a coolant which the condensate flows into a round-bottom flask 14 serving as a collecting container, which has an outlet opening and is equipped with an opening at the bottom for draining the condensate.

Remaining gases flow from the collecting container (round bottom flask) 14 into another one filled with water as a coolant Condenser 15, which is expediently arranged above the collecting container H.

The residual gases flowing out of the condenser are then passed through washers connected in series. In the embodiment shown is (a) a washer operated with water as washing liquid, (b) one with ethanol or with methanol washer operated as washing liquid, (c) a washer with a solution of 1 mol of KOH in 135 ml of methanol as washing liquid operated washer, (d) a washer operated with benzene as washing liquid, (e) one with a solution of 1 mol of KOH washer operated in 2 mol of water as washing liquid and (f) a washer with an approximately 24% solution of 98? iger HgSO * as washing liquid operated washer provided. An empty scrubber can be connected downstream to prevent kickback.

The remaining gases are discharged via a line and expediently discharged in a suitable manner.

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formed catching device. Before one switched into the line between the scrubbers and the collecting device Gas flow meter 17 can be a chromatography. pipe to be able to analyze gas samples. A chromatography tube can also be switched on at other desired points in the work-up section To be able to analyze gases or distillates.

A gas flow meter connected to this line and calibrated in fractions of a cubic meter shows the Sum of generated hydrocarbon gas.

In carrying out the process of the sulfur-containing lignite is introduced into the reaction According and heated to a temperature of 35 to 50 ⁰ C. After the system had been purged with hydrogen or nitrogen and thus removed atmospheric oxygen from the system, 50 ml of reagent was introduced. The system was then closed and then ^{heated to 65 0} G, at which temperature the methanol originating from the reagent distilled off. As already mentioned, the mixture of reagent and lignite can be kept sufficiently in motion by the nitrogen supplied. The reagent also contains water, which is present as an impurity contained in the starting materials used to produce the reagent and which is also partly formed during the production of the reagent. The water introduced with the reagent V / ater and introduced with the coal water is distilled off at temperatures up to 135 ⁰ C.

The distillate obtained during the distilling off of the methanol or the ethanol also contains in methanol or in Ethanol soluble hydrocarbons, including gaseous ones Hydrocarbons. The water distills from the reaction mixture only after most of the methanol or the ethanol has been distilled off. This water can contain a small amount of amber-colored liquid hydrocarbons contain, the amount of which increases as the quality of the coal increases. As a rule, a small amount goes out of the reaction mixture Amount of liquid hydrocarbons at a temperature

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from 135 to 190 ^° C., the amount of these liquid hydrocarbons also increasing as the quality of the coal increases. These liquid hydrocarbons condense in the water-cooled condenser 13 on its walls 13a in the form of a solid or semi-solid product.

After the mixture of water and methanol has been distilled off from the reaction mixture, the supply of hydrogen or nitrogen can be changed if necessary. At this point in time, that is to say when a temperature of about 170 to 190 ^° C. is reached, steam or a suitable stirrer can be used exclusively to mix the reaction mixture. Steam is therefore not introduced into the reaction vessel before the mixture of methanol and water is distilled off, because the mixture of methanol and water / water maintains the temperature within a certain temperature range during the distillation of methanol and water.

Following the supply of steam or of Water vapor with continued supply of hydrogen gives different lignites of sub-bituminous coals depending on their composition and their internal structure, various amounts of detectable gaseous hydrocarbons and various Distillation areas.

When introducing steam into the reaction vessel, it is advisable to terminate the supply of hydrogen, since in the In the case of supplying hydrogen into the device, an accurate reading of the volume measurement of the exiting the device Gas is made more difficult, but when using a further gas flow meter on the hydrogen container, the Amount of hydrogen supplied to the system can be detected and this amount is determined by the arranged at the outlet of the device Flow meter 17 displayed value can be subtracted. It should be mentioned, however, that some of the hydrogen the coal used is hydrogenated and therefore the amount of hydrogen is not precisely determined by the arrangement mentioned can be.

In the cone begins with the processing of inferior ones

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3028643

Coals at the boiling point of methanol or ethanol gradually develop gaseous hydrocarbons, the amount of gaseous hydrocarbons formed increasing as the reaction mass is heated ^{to about 280 ° C.} In the case of higher quality coals, at these low temperatures, that is to say at temperatures of up to about 280 ^° C., only a few gases or no gases at all are produced. Most of these gases are retained in the washers, so that only a very small amount of gas throughflow is displayed on the gas flow meter 17.

However, the amount of gas can be measured when the system is removed or bypassed by series-connected scrubbers and the reaction of the alkanolic reagent with the elemental and organic sulfur generated hydrogen sulfide separately blown off or measured or with a suitable aqueous reagent (the organic sulfur is chemically bound in the coal).

As already mentioned, the initially resulting quantity of gas is low and is, for example, lignite at temperatures below 280 ⁰ C for about 0,0015b 0,00067b to nr / g bO wet lignite, but this amount will vary depending on the type of coal used.

Methane is emitted first and is the largest in comparison to the other hydrocarbons that are formed Solubility in all washing liquids used in the washers. Pentane, hexane, hexene, and pentene are more effective in water also considerably soluble in the washing liquids used in the system. Hexenes and hexanes condense in the water-cooled Capacitor and are only carried to the extent that they enter as vapor in the lighter gases sweeping over the liquid, depending on the partial pressure. One of the gas flow meters 17 passing gas components is Athens. Athens is into petroleum hydrocarbons, water and Alcohol, which can be used in the various washers 16, is only sparingly soluble. Athens has the one for unsaturated Hydrocarbons characteristic odor, whereas

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ι
saturated hydrocarbons are odorless. The solubility of unsaturated gaseous hydrocarbons in sulfuric acid can be used to separate unsaturated hydrocarbons from saturated hydrocarbons.

As soon as a temperature of 535 ° C has been reached, the originally used 100 g of coal (moist lignite or sub-bituminous coal) produce 1 to 5 carbon atoms (gaseous hydrocarbons) at a faster rate. As soon as a temperature of 360 ^° C. has been reached, the gas production increases considerably. When a temperature between 380 and 450 ^° C. has finally been reached, gaseous hydrocarbons are produced at a very high rate, with some hydrogen also being produced. At a temperature of 360-380 ⁰ C and carbonyl sulfide, which can apply the total amount of gaseous hydrocarbons at sub-bituminous coal, for example in an amount of 4 wt .- ^ _f 7 is formed.

The gases produced at these higher temperatures pass through the scrubber and are recorded by the gas flow meter. For example, from 100 g of moist sub-bituminous coal, after deduction of hydrogen sulfide, in the cone up to 0.0378 nr (1.4 cubic feet) of gas when this coal contains 47 grams of carbon on a dry matter basis.

Under normal temperature and pressure conditions, approximately 3.7 moles of 47 grams of carbon-containing gas will contain one average carbon content of ii, 25 for a product. It must also be pointed out that the various Products obtained at temperatures consist of various breakdown products.

In the course of example 1 carried out gasChromatograph! Sch « Analyzes strongly suggest that there are two hydrogen atoms for every carbon atom in gases. The deployed Lignite contained one hydrogen atom per 1.38 carbon atoms or, converted, 0.7 ^ 5 hydrogen atoms per carbon atom. The gas chromatography analysis did not provide any for one either significant oxygen content of the gases

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and spoke in favor of the fact that the captured gases consist almost entirely of hydrocarbons. Containing 1 to 6 carbon atoms Hydrocarbons in this fraction are either gases or highly volatile liquids.

In the scrubbers, the carbon dioxide is converted into potassium carbonate by means of ethanolic or methanolic potassium hydroxide solution pleases. As a rule, a solution of 1 mole of KOH in 2 moles of water is used, this aqueous solution of an alkali metal hydroxide If necessary, an alkanol can be added can.

Example 2: 25 g of technically pure sodium hydrosulfide flakes were mixed with 100 g of sub-bituminous coal (Maverick sub-Bxtuminous coal). Technically pure, flaky NaHS often shows different analytical values. The sodium hydrosulfide used here contained about 30 wt. -Jo water. The sodium hydrosulfide flakes were piled up in the reaction vessel on the charcoal previously introduced into the reaction vessel. The coal used contained 3.3% by weight of water, 12.9% by weight of ash, 0.69% by weight of S, 70.2% by weight of C, 4.4% by weight of H, 1.13% by weight of N and 6.16% by weight of £ 0. The calorific value of the coal was 2.95.10 ⁷ J / kg (12 656 BTü / lb).

The equipment was ^{heated to 280 °} C. in the reaction vessel. Steam heated to 140 ° C. was blown into the reaction vessel from the bottom in order to keep the reaction mixture in motion and to supply the hydrogen required for the carbohydrate hydrogenation. The steam was injected after a temperature was reached by 17b ⁰ C '. There is reason to believe that the hydrosulfide used was at least partially converted into the sulfide during the heating of the reaction mixture because of the water content of the reagent and the carbon.

Below 175 ^° C., a few clear drops of hydrocarbons distilled off together with the originally expelled water. At a temperature up to 175 ° C the reagent rose, probably because of the formation of a lower hydrate of kaxrium sulfide and because of the subsequent decline.

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splitting water, high.

At 280 ⁰ C, gaseous hydrocarbons were produced continuously, so that at the end of the system a i'Iamme could be maintained in a glass tube. The gases were washed with water before flaring. In 5bO ⁰ C the experiment was discontinued after the coal was about halfway implemented.

In a water cooled condenser 15 of a liquid distillate was collected ml, which is 9.8 wt .- ^ is hydrogen, 87 wt .- ^ carbon, 0.67 wt .- $ sulfur and 0.07 weight - containing ⁰ Jo nitrogen.. According to gas chromatography, the gases consisted exclusively of Athens. About 0.8 cubic feet (0.0216 m ⁵ ) of gas was produced.

Without being limited to any particular theory, will assumed that in the process of the invention from the coal oxygen, sulfur and nitrogen in the course of a number are split off from complex reactions, which, as will be explained later, by sulfur compounds of potassium or, in an equivalent manner, by sulfur compounds of other alkali metals. Those in attendance Reactions of water and hydrogen sulfide yield hydrogen, which with coal is split off of oxygen, sulfur and / or nitrogen reacts, it seems necessary for the practical implementation of the invention to be that the coal contains oxygen, however, the desired effect may also be organic because of that in the coal bound sulfur or nitrogen can be achieved. Higher quality coals, such as bituminous coals (Bituminous coals) cannot be converted into gaseous hydrocarbons that easily, but can be explained in more detail later Way hydrocarbons can be obtained from hard coal if the reaction conditions are modified accordingly will.

It was found that coals with a carbon content of less than about 70 % by weight can be gasified almost entirely and only b % by weight of a solid residue and / or one

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liquid distillate incurred, tine about 75 wt .-> C containing coal provided about 10 wt .- $ of a liquid distillate and the remainder gases. A 82.5 wt .- $ C containing coal supplied 33 percent -. "/> A liquid distillate and the residual gases A 92 wt .- 6 C containing anthracite gave little gas and only about 2 percent .- ^ one.? Liquid to Solid Distillate If a sodium-based reagent was used in place of the potassium-based reagent, approximately the same amount of liquid distillate but a lesser amount of gases was obtained.

For the reasons mentioned, within the scope of the invention Process preferably gasified lignite and sub-bituminous coals. In addition, the inventive method also applicable to sub-lignites and even peat, however gasification of sub-lignites and peat is in view less economical due to their lower carbon content.

Rubidium sulphides are also effective, but for practical reasons potassium hydrosulphide is preferred. Sodium hydrosulfide and also sodium polysulfide also enable the necessary conversions. Hydrosulfides and polysulfides of cesium, rubidium and potassium can generally be used in the context of the invention, but hydrosulfides and polysulfides of cesium and rubidium are not advantageous for reasons of cost. Hydrosulfides and polysulfides of lithium are also useful, but less effective than those of sodium. The sulfides of the metals mentioned can also be used. A mixture of sulphides (hydrosulphides, sulphides and polysulphides) of rubidium, potassium and sodium gives a greater degree of effectiveness than any one of the hydrosulphides, sulphides and polysulphides mentioned. The preferred mixing ratio of hydrosulfides, sulfides and / or PoIysulfiden is expressed as the weight ratio of the elements, 14 wt -. $> Rubidium, 26 wt .- 4 potassium and 60 wt .- # sodium?. This weight ratio is generally 1: (1.5 to 2.5): (3.5 to 4.5) Rb: K: Na.

Potassium hydrosulfide is usually used in an amount of

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5 to 30 g per 100 g of coal, preferably about 10 to 25 g each 100 g charcoal, in particular 18 g per 100 g charcoal, are used. This reagent is recovered in a manner to be explained later. If the potassium contained in the ashes of the coal is converted to potassium hydrosulfide, there is no loss Potassium hydrosulfide, with which both the batch and continuous work according to the invention Method gives a very favorable reagent balance.

It must be pointed out that sulfur, sulfides, hydrosulfides and / or polysulfides should be present in such amounts that they can absorb the sulfur split off from the coal during the splitting off of oxygen and thus dehydration of the coal by the split off sulfur at a temperature above 17b ⁰ C, it must also be ensured that the various reagents are stable at temperatures above 325 ⁰ C, since at temperatures above 325 ⁰ C the carbon would be dehydrated by molten alkali metal hydroxide. But among other things, sulfur gives rise to the formation of more hydrolysis-resistant polysulfides, a decomposition of a possible hydrolysis product, u.zw. of the hydrosulfide, can be avoided by steam or water. The required amount of reagent can thus be determined for each type of coal on the basis of the above stated ranges of amount and composition of the reagents and on the basis of the sulfur content of the coal.

When calculating the sulfur contained in coal only the organically bound sulfur, i.e. the sulfur bound to carbon, is taken into account. More present in the coal Nitrogen is converted into ammonia, which is used when working can be recovered as a valuable by-product on an industrial scale.

As indicated above, steam is used at a temperature at which the reaction is to be carried out. Lie The temperature of the steam is therefore dependent on the type of coal used and the degree of degradation of the coal to be achieved and the desired products selected. Water vapor also delivers

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Hydrogen, which obviously ^{originates from H +} and not from OH ~ ". Water vapor of the desired temperature can be generated in the steam generator 10 shown in the figure Hydrocarbons with an average of 1 to 2 carbon atoms are formed from coal through hydrogenation.

As the sulfur content of the reagent increases due to the sulfur derived from coal and added elemental sulfur, the reaction temperature is reduced. A reaction temperature of 380 ⁰ C can be lowered to 310 ⁰ C, for example, when on - the basis of the sulfur balance can theoretically a compound of formula K ^ S * calculated. The reason for this measure is that higher molecular weight hydrocarbons, for example pentanes such as isopentane and n-pentane, are formed.

In addition, the composition of the distillate obtained is influenced by the quality of the coal under otherwise identical working conditions, for example when using the theoretical connection KpSv and adhering to the the same temperature conditions, the higher the quality of the coal, the greater the amount of liquid distillate will.

As already mentioned above, a change in temperature also changes the composition of the process product changes. As mentioned above, a change in the composition also results when the amount of sulfur changes of the process product.

Based on the above information, one can thus determine the working temperature and change the sulfur content, select a coal of a certain quality and add it later illustrative way recycle a mixture of an alcohol and a distillate to a process product of the desired Composition. TJm the composition of the

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Changing the driving product can also lead to a return of various other distillates occurring in the system according to FIG. 1 and / or products occurring in the washers are intended will.

For the changes in the working conditions specified above, the following options are available, among others: the working temperature is increased to 425 ^° C., but the distillation is started at 40 to 50 ^° C. The sulfur content; The example of a reagent based on potassium is changed in the reagent, it being possible for the sulfur content to be increased from the composition K "S to the composition K ₂ Sc. A coal in the quality range ranging from lignites to bituminous coal (hard coal) is expediently selected as coal. When using anthracite, the results are less favorable, although here, too, when using a (high-sulfur) reagent such as KgS. ^ ei ^e i can be obtained ^ner operating temperature of 380 ⁰ C, a distillate ·.

Usable reagents based on sodium result from the use of NaHS and sodium sulfides in the composition Na ^ S to Na ^ S ^. NaHS is opposite to coal or Water from the steam is more stable than KHS and delivers a distillate at correspondingly lower temperatures than KHS, whereby the temperatures are around 10 to 20 C lower than at KHS, but also a slightly smaller amount

the end

Distillate is obtained than at KHS. That is not advantageous in terms of cost Rubidium gives at least as good and often better results than potassium.

If the alcoholic distillate, which may contain hydrocarbons and is collected in the collecting vessel 14 of the figure, is returned to the reaction vessel 11, the composition of the process product is also changed. The amount of recycled alcoholic distillate can also be selected differently. At a working temperature of up to about 280 ^° C., the composition of the process product can be shifted in the direction of a liquid distillate with a boiling point below about 180 ^{° C.} at

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an operating temperature of up to about 310 ^° C., when the alcoholic distillate is returned to the reaction vessel, paraffin desxillates are obtained. When returning the alcoholic distillate to the reaction vessel, as before, water must be present in the form of steam at a temperature of about 135 ^° C. so that the reaction can take place.

If an alcoholic distillate is recycled, methanol is preferably used as the alkanol. By repatriation of the alcohol containing the original reaction products dissolved in the reaction vessel can thus be achieved that a larger amount of liquid distillates is obtained.

If the process is started by increasing the temperature outside of room conditions, sufficient elemental sulfur is added to the carbon or reagent to provide the chosen sulfur content of the reagent. The hydrogen sulphide produced when the sulfur reacts with the reagent in the system is washed out of the grass stream and reused from the scrubber outlet to produce reagent. Steam is not used in the initial temperature increase so that the hydrogenation of the coal must be effected by the water contained in the coal or in the reagent. Steam can be fed in at a temperature of about 135 ^° C. if light distillates are desired. In any case, water vapor is supplied at a temperature at which a hydrate of the reagent begins to convert into a lower hydrate. When using sines! SieagEJis on the basis of potassium is fed steam at a temperature of about 170 ⁰ C.

When hydrates change to lower hydrates and give off water of hydration, considerable amounts of steam are created. this is the signal that water vapor can be safely supplied as long as the water of hydration leaves the reaction vessel Has.

The process according to the invention can also be carried out continuously. As a rule, a specific one is used here Working temperature selected and carbon and reagent in one

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Reaction zone introduced with ash removed and reagent and alkali metal compounds formed from the reagent are recovered and the reagent, for example by means of Hydrogen sulfide, is fortified. ! Liquid and gaseous Fractions are usually in a distillation column or separated off in suitable washers, hydrogen sulfide also being separated off. In such a completely continuous process, in which also the reagent is recovered, a material recycling (alcoholic distillate for Reaction zones) are provided to a process product of the to obtain the desired composition. The working temperature and other working conditions can also be adjusted accordingly the above information can be varied.

If information on suspected complex reaction mechanisms it must be borne in mind that this information is based only on conclusions and numerous responses run at the same time, which is why the following declarations can in no way claim to be correct and represent a theory serving to explain the invention, to which the present invention is not limited.

If so, that K-Sc in a closed and Lxift oxygen-free system at elevated temperature with the oxygen of the coal and all coordinated sulfur atoms of the pentasulfide are replaced by oxygen is oxidized directly to K ^ SCK, then the reaction would lead to Come to a standstill when the K-Sc has been converted to ^ SO * is.

KpSO. would now represent an inert substance in the system, unless it would be converted to carbon monoxide and K-S by reduction by the carbon of the coal. If Should this process actually take place, there would be a risk of the potassium sulfide reacting with the carbon monoxide to form potassium carbonyl, an extremely explosive connection. In the method according to the invention, as can be seen from the analysis

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_ 29 _

of the gases in the chromatography lines does not yield any significant amount of carbon monoxide or carbon dioxide.

It is known that elemental sulfur at 'i'emperaturen above 175 ⁰ C dehydrated coal ^ "Mazumdar et al., Ff Fuel, Vol. 41, p.121., (1962} ^. Furthermore generated when oxidizing with air of Kaliuinpentasulfid elemental sulfur, potassium thiosulfate (K ₂ S ₂ O ₅ ) and potassium tetrathionate (K ₂ S ₄ O ₅ ) / Letoffe et al., Journal Chimie Physique, Vol. 71, pp. 427-430 (1974) 7 · Potassium pentasulfide is at 300 ⁰ C slowly decomposed to potassium tetrasulfide and sulfur, but the reaction rate increases with increasing temperature ^{above 300 0 C.}

Potassium sulfide retains 5 molecules of water of crystallization at temperatures up to 150 ^{° C. and converts to the dihydrate at 150 °} C., which is decomposed at 270 ° C. to a solid lower hydrate, which in turn is dehydrated ^{to a greater extent at temperatures between 779 to 840 ° C.} , with the potassium sulfide already being decomposed to potassium disulfide and elemental potassium within this temperature range, which in turn is soluble in the solid sulfide. Kaliumthiοsulfat (K ₂ SpO) is decomposed at temperatures above 200 ⁰ C to potassium sulphate and potassium pentasulfide, the latter what at 300 ⁰ C and higher temperatures potassium tetrasulfide and sulfur is decomposed.

If the reagent is potassium hyarosulfide (in an alkanol) is used, the potassium hydrosulfide is replaced by the in the Coal and that contained in the solution of potassium hydrosulphide Water hydrolyzed to hydrogen sulfide and potassium hydroxide. The resulting potassium hydroxide reacts with undecomposed Potassium hydrosulfide to form hydrated potassium sulfide and water. Das.by reaction of the organically bound in the coal Sulfur and the added elemental sulfur, the potassium pentasulphide formed correspondingly forms potassium hydrosulphide the equation

KHS + 2S = 1 / 2K ₂ S ₅ , + 1/2 H ₂ S pure sodium, the reaction equation applies

NaHS + 1 1/2 S = 1/2 Na ₃ S ₄ + 1/2 H ₂ S

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No polysulphides with a medium sulfur content are formed (Sulfides with 2 to 5 sulfur atoms), which is why inadequate Amount of sulfur a part of the KHS is not converted. This conversion only takes place in alcoholic solutions. at Only the tetrasulphide is formed from sodium compounds.

A lower sulfur content than the potassium pentasulphide Potassium sulfides containing potassium are converted to potassium by oxygen decomposed.

In summary, it follows that, to the extent that nitrogen is organically bound sulfur and also oxygen be split off, the water or the hydrogen sulfide formed from water and the reagent to that of oxygen, Sulfur and nitrogen-free coal gives off hydrogen. The nitrogen is mainly split off in the form of ammonia, whereas the split off sulfur is an alkali metal polysulphide, for example a potassium polysulfide, and at low Temperatures with the alkanol used as solvent forms a mercaptan. The resulting mercaptans are in the alcohol or dissolved in the alcoholic solution of the kOH.

That in one of the scrubbers in the form of a solution in methanol KOH used provides the thiosulfate, which is insoluble in alkanols. This reaction is due to a reduction in hydrogen sulfide to sulfur and water and the subsequent reaction of the sulfur with the KOH to form potassium thiosulfate and potassium sulfide traced back. The potassium sulphide can absorb further sulfur from hydrogen sulphide and thus a potassium polysulphide form and together with the potassium polysulphide forms the reagent used in the reaction.

As a rule, the breakdown products formed at different working temperatures have different compositions. The working temperatures can be chosen so that end products with a desired content of volatile distillates and gas fractions suitable for a specific application are obtained. For example, when processing a sub-bituminous coal according to the invention, the result was 80.19 ^c ß> methane, 9.12 ^c /> ethane, 1.41 ° J> Athens, 2.67 fo propane,

1300 13/0973

"If worked 1.41> propene, isobutane 9b 0.16, 0.31 ° f> n-butane, 0.001 $> hydrogen sulfide and carbonyl sulfide 4.72 fi and the balance unidentified gaseous components containing gas at 340-365 ⁰ C. became.

From the above, it can be seen that with the invention, a low temperature and low pressure recovery of the reagent in a simple manner feasible process for producing hydrocarbons from coal was created.

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Claims (1)

Patent claims: Ij / Process for converting coal into gaseous hydrocarbons and volatile distillates, characterized in that coal or peat and one hydrosulphide or sulphide at least of an alkali metal in the presence of water and optionally sulfur at a temperature between 50 and 450 ° C and volatile liquid distillates and gaseous hydrocarbons are recovered. 2. A method for converting coal into gaseous hydrocarbons and volatile distillates, characterized in that coal or peat and an alkanolic solution of an alkali metal allhydrosulf ids, an alkali metal sulfide, an alkali metal polysulfide or a mixture thereof at a temperature of 50 ⁰ C and above in the presence reacted by water and the reaction is continued at a temperature of up to 450 ⁰ C and volatile liquid distillates ur.d gaseous hydrocarbons are separated. 3. The method according to claim 2, characterized in that elemental sulfur is added to the alkanolic solution of the alkali metal hydrosulfide. 4. The method according to claim 2, characterized in that the alkali metal hydrosulfide is potassium hydrosulfide, liatrium hydrosulfide or a mixture of hydrosulfides and sulfides of rubidium, potassium and sodium is used. • 5. Process for converting coal into gaseous hydrocarbons and volatile distillates, characterized in that they contain oxygen, sulfur or nitrogen in bound form Coal or peat containing these elements in bound form is reacted with a reagent which is an alkali metal hydrosulfide Alkali metal polysulphide or a mixture thereof or a mixture of hydrosulphides or polysulphides of different alkali metals contains that the reaction is carried out in the presence of steam at temperatures between 135 and 450 g that volatile distillates and gaseous hydrocarbons are separated and that the reagent is recovered or regenerated will. 130013/0973 bad original 6. The method according to claim 5, characterized in that that as coal lignite, sub-lignite, bituminous coal (bituminous coal) or sub-bituminous coal (black lignite) or anthracite is used. 7. The method according to claim 5 or 6, characterized in that that a reagent containing potassium is used as an alkali metal will. 8. The method according to claim 5 or 6, characterized in that that as a keagent a mixture of hydrosulfides, sulfides and / or polysulfides of the alkali metals rubidium, potassium and Sodium is used. 9. The method according to claim 5 or 6, characterized in that a reagent containing sodium as an alkali metal is used. 10. The method according to any one of claims 5 to 9, characterized characterized in that part of the distillate is recycled in the form of an alcoholic solution during the reaction to participate in coal or peat with reagent. 11. The method according to any one of claims 5 to 10, characterized characterized in that the reaction takes place at a temperature 170 and 380 C is made. 12. Continuous process of converting coal or peat into gaseous hydrocarbons and volatile ones Distillates, characterized that in a reaction zone maintained at a temperature above 160 ° C. ^and up to 450 ^° C., steamed coal or peat at a temperature of 100 ^° C. or above is introduced continuously and freed from air by heating, that the reagent is a hydrosulfide, a sulfide or a polymiliid an alkali metal. or several alkali metals or a Mixture of hydrosulfides, sulfides and polysulfides or an alcoholic solution of this reagent is fed continuously will, that is introduced into the reaction zone of steam at a temperature between 160 and 4i? 0 ⁰ C, 1 3 OQ 13 / ö 9 1 3 BAD ORIGINAL that the coal "or the peat and the reagent in the reaction zone" are present at a predetermined temperature of the supplied steam are continuously reacted with one another, that volatile distillates and / or gaseous products are withdrawn from the reaction zone, that hydrogen sulfide or carbon oxysulfide are withdrawn from the reaction zone, that the ash is withdrawn from the coal or from the peat from the reaction zone, that contained in the ash of the coal or the peat unreacted reagent una in the ash of the coal or the Alkali metal compounds contained in peat are recovered as alkali metal hydroxides, that alkali metal hydroxides are reacted with hydrogen sulfide formed during the reaction and that Reagent is restored and that a sufficient amount of recovered reagent is introduced into the reaction zone to prevent the reaction to continue between the coal or peat and the reagent. 13. The method according to claim 12, characterized in that for the purpose of producing gaseous hydrocarbons Reaction zone is maintained at a predetermined, set temperature. 14. The method according to claim 12, characterized in that the reaction zone on a for obtaining a predetermined Hydrocarbon fraction is maintained at a suitable temperature. 15. The method according to claim 12, 13 or 14, characterized characterized in that an alcoholic solution containing a portion of the distillate in dissolved form is returned to the reaction zone will. '■■ 16. The method according to any one of claims 12 to 1ί>, characterized characterized in that the reagent is potassium sulfide, a potassium polysulfide, Potassium hydrosulfide or a mixture of at least two the same is used as a reagent. 17. The method according to any one of claims 12 to 16, characterized in that a temperature between 155 and 450 ⁰ C ₁ in particular between 170 and 450 ⁰ C is maintained in the reaction zone. 18. The method according to any one of claims 12 to 15 and 17, characterized in that the reagent sodium and potassium hydrosulfide, a sulfide, a polysulfide, or a mixture thereof is used. 19 · method according to one of claims 12 to 15 and 17, characterized in that a mixture of rubidium, Potassium and sodium polysulphide, sulphide or hydrosulphide or a mixture of such polysulfides, sulfides and hydrosulfides is used. 20. The method according to any one of claims 12 to 15 and 17 to 19, characterized in that sodium hydrosulfide technical Degree of purity is used as a reagent. 21. The method according to any one of claims 1 to 20, characterized in that the reagent by reacting an alkali metal hydroxide restored or regenerated in a saturated alcoholic solution with hydrogen sulfide is that the reagent is precipitated as a mixture of the sulfide and the hydrosulfide of the alkali metal of the hydroxide and that the precipitate is recovered as a reagent for reaction with the coal or peat. 22. The method according to any one of claims 12 to 21, characterized in that the gaseous hydrocarbon with a Washed solution of an alkali metal hydroxide and thus from the hydrogen sulfide formed as a reaction product with the alkali metal is freed and that the reagent is separated for recycling. 23 · The method according to any one of claims 12 to 22, characterized characterized in that the gaseous hydrocarbons are distilled to obtain a desired fraction. 24. The method according to any one of claims 12 to 23, characterized in that, based on the material balance, a reagent the theoretical composition K ^ S ^ is used. Ή 3 2ij. Method according to one of Claims 12 to 24, characterized characterized in that anthracite partially reacted with the keagent will. 130013/0973