DE3108798A1 - METHOD FOR LIQUIDIZING COAL - Google Patents

Abstract

The method for the liquefaction of coal by catalytic transformation of coal in a suspension of hydrocarbon oil having a high boiling point, and for the conversion of heavy and waste oils under high temperature and pressure in the presence of hydrogen, is carried out in the presence of a catalyst obtained by association of iron sulfate with an under-stoichiometric quantity of an alkaline compound. To this effect iron sulfate hydrates may be used.

Description

Process for liquefying coal

The invention relates to the use of an iron sulfate containing Catalyst for the liquefaction of coal in the presence of hydrogen under increased pressure and temperature.

The liquefaction of coal by heating a slurry of the Coal in hydrocarbon oils under increased pressure in the presence of hydrogen and a finely divided catalyst is known. While one in the beginning who carried out the coal conversion at pressures of around 500-700 bar is what we are today endeavors for reasons of economy, at lower pressures, z. B.

100-300 bar to work. However, this sets the presence accordingly more effective catalysts.

As catalytically effective substances are, for. B. Connections of Known as molybdenum, tungsten or nickel. However, these lose relatively quickly, z. B. by carbon deposits and the formation of high-boiling aromatic condensation products on them, their activity. One has therefore looked for cheaper connections that have sufficient catalytic activity, and is to be used Iron compounds passed, in particular iron oxides, as they are, for. Tie so-called lux or Bayer masses are available (Fuel Processing Technology 1 (1977) 10-13). Iron-rich bauxites or zeolites were also used as catalysts suggested, paying attention to the presence of H2S (DE-PS 926 664). It a complete neutralization of the iron sulfate z. B. with sodium carbonate suggested, whereby this was used in a superstoichiometric amount (FR-PS 793.108).

Another suggestion is to use subbituminous coal containing calcium initially z. B. treated with an aqueous solution of iron sulfate to thermally Form stable calcium compounds that are separated from the solution when used and then dried coal for hydrogenation in the presence of conventional catalysts, z. B. cobalt-molybdenum compounds, not to the otherwise frequently occurring deposits to lead in the reactor (DE-OS 28 07 203). Overall, the could for high Reaction pressures developed iron catalysts at the relatively low ones desired Pressing does not satisfy, so it was necessary to be sufficiently active, however to develop inexpensive catalysts.

It has now been found that one can solve this problem and coal, in particular Lignite, in a slurry in a high boiling hydrocarbon solvent catalytically at temperatures of 420-4900 C and under pressures of 80-500 bar in The presence of hydrogen can liquefy if one is in the presence of a catalyst works by reacting iron sulfate with a substoichiometric Amount of an alkali compound was obtained.

Pure iron sulphate, e.g.

in the form of iron (II) sulfate heptahydrate, but also corresponding ones technical salts, e.g. B. that in the production of titanium dioxide as a by-product Use any so-called green salt, which mainly consists of Fels04.7 H20. Alkali compounds include, in particular, caustic soda, but also potassium hydroxide and To understand ammonium hydroxide and the corresponding carbonates and sodium sulfide. You give a substoichiometric amount of these compounds, based on the present iron sulfate, too. This can e.g. B. done so that the iron salt mixed with water to a pulp and in this the appropriate amount of alkali compound enters, where z. B. a pH between 4.5 and 7.5, but also if desired even higher, can be set. Iron oxide can advantageously be added to the catalyst can be added in pure form or in the form of the known technical compositions. as such masses are mentioned z. B. Bavarian mass, lux mass, red mud, lawn iron ore.

It goes without saying that the addition of additional products is also more catalytically effective Metal oxides possible. You can also use iron sulfide, e.g. B. in the form of pyrite, admit.

If the catalyst is in dry form e.g. B. on the hydrogenation the intended charcoal is to be applied or added to a charcoal / oil mixture, becomes that in the reaction mixture obtained existing water in usual Way removed, generally setting a water content below 10% will. The dry catalyst is then used for the hydrogenation Ground grain fineness, the z. B. with a grain size smaller than 500 ß. Of course the catalyst can also be in aqueous form, for. B. applied to the coal and dried together with it. The catalyst of the invention is so active that in general, e.g.

even when using Rhenish lignite, quantities for hydrogenation of 1-5% Fe, based on the coal used, for sufficient liquefaction expansion suffice. It is advisable, in a known manner, in addition to the catalyst, sulfur, e.g.

2%, based on the coal, to be used or during coal liquefaction to ensure a sufficient content of hydrogen sulfide in the hydrogenation gas. the Coal liquefaction can moreover be carried out in a known manner and in the known apparatus be performed.

Example 1 kg of technical iron sulfate with a water content of 38% was mixed with 180 ml of water to a paste. There were 110 ml of 10% sodium hydroxide solution added, a pH of 5.5 being established. The well-mixed porridge was dried at 140 ° C to a water content of 3% and then so far ground that 82% of the catalyst was present with a grain size smaller than 50 ß.

To a mixture of finely ground brown coal (39 wt.%) And one High-boiling mashing oil originating from the lignite hydrogenation was 4% by weight Catalyst and 1.2% by weight of sulfur, based on the coal used, were added. Subsequently, the liquefaction of the brown coal at 470O C and under one Carried out a pressure of 280 bar, a coal conversion of 98% was achieved.

In another similar experiment, 4% of the figure in the first paragraph mentioned inventive catalyst used, the 20% Bayer mass, a mixture of mainly oxides of iron, aluminum, silicon and titanium, added was. The coal turnover here was 96.8%.

When repeating the first attempt, but with a catalyst from iron sulfate, which was neutralized with equimolar amounts of sodium hydroxide solution, was only get a coal turnover of about 86%.

Claims (4)

Claims 1. A method for liquefying coal, in particular Brown coal, by catalytically converting the coal into a slurry in one high-boiling hydrocarbon solvents at temperatures of 420-490 ° C and under pressures of 80 - 500 bar in the presence of hydrogen, characterized in that that one works in the presence of a catalyst which is produced by the reaction of iron sulfate was obtained with a sub-stoichiometric amount of an alkali compound. 2. The method according to claim 1, characterized in that hydrates of iron sulfate begins. 3. The method according to claims 1 and 2, characterized in that the pH of the reaction mixture is adjusted to 4.5-7.5. 4. Process according to Claims 1 to 3, characterized in that iron oxide or iron sulfide is added to the catalyst.