DE3124814A1 - METHOD FOR PROCESSING COAL EXTRACT - Google Patents

Description

Method of processing coal extract

The invention relates to the processing of coal extracts, in particular to the hydrogen cracking of
Coal extracts.

Coal extracts, well known in the coal chemistry art, are made useful by digesting coal particles in a solvent at high temperature
300-450 ⁰ C, produced under pressure for a period of 30 minutes to 2 hours. Thereafter, the remaining carbonaceous and mineral material is removed, which can be done in a number of ways, including centrifugation and filtration. Another method of producing coal extracts involves dissolving the coal substance in a supercritical fluid and separating the solution from the remaining material. These
"Supercritical gas extraction" processes have already been described.

It has recently been proposed that coal-derived materials be either catalytic or non-catalytic hydrogenate. to increase the yield of liquid products for fuel

To increase substances or chemical starting products. One such well-known proposal was the "Synthoil" process, which was carried out in a pilot plant in the USA for several years. A mixture of a slurry of coal in recirculated oil and hydrogen was passed through a tubular reactor which had previously been _{filled with Co-Mo / Si0 2} - AlpO ₃ catalyst spheres, the gas was separated off and the liquid was passed through a solids separation device to remove high-melting carbon and mineral material. The tubular reactor was then heated in an oven with temperature control of the exothermic reaction achieved in part by the addition of cooling oil. The reactor was operated under disturbance conditions which ensured turbulent disturbance as it was believed that this would prevent the deposition of ash on the catalyst surface. Experience, however, has shown a significant rate of catalyst deactivation and contamination which, among other problems, has resulted in the abandonment of the Synthoil process.

The invention provides a method for hydrotreating coal extract or coal oil containing less than 0.1% ash, wherein the extract or oil and hydrogen are passed through a tubular reactor immersed in a bath of fluidized particles , and at a temperature of 350-450 ⁰ C and under non-streamlined flow conditions, wherein the catalyst comprises a hydrotreating catalyst fixed bed.

The tubular reactor expediently has a possible small ratio of inner diameter to length, since this increases the area of the catalytic converter that is connected to the walls of the Reactor is in contact, is relatively increased. If the catalyst is completely or partially loaded with a dripping bed

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is driven / it has been found that the flow of fluid is caused by the formation of fluid channels in the vicinity of the walls shifts considerably, so that by increasing the relative extent of the contact between the catalyst and the wall, the contact between the catalyst and Fluid is increased. Preferably, however, the catalyst is operated flooded, since it has been shown that this a better contact between catalyst and liquid results. However, physical constraints make it regarding the reactor structure, for example the necessity to bend the reactor so that it fits into a fluidized bed requires successive lengths of the reactor as a dripping bed or flooded. The reactor can be of any convenient shape.

The use of a fluidized bed into which the reactor is immersed offers considerable advantages achieves that extremely precise temperature control is achieved without adding cooling oil or hydrogen to the reaction mixture, thereby causing the reaction to take place is obviously affected. Continuous reaction temperatures are endothermic in such catalytic Reactions pose a problem. The particles that make up the fluidized bed form, can be any particles that are stable at the reaction temperature and as a heat carrier without excessive output losses can be used. Corundum and aluminum oxide are suitable materials for the Layer to form.

A commercially available hydrogen cracking catalyst is suitable as the hydrogen treatment catalyst, expediently of the Co / Mo - or W / Ni - on-SiO ^ / Al-Oo type; however can also

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other catalyst can be used. Sometimes the use of a protective catalyst / such as alumina, which contains small amounts of cobalt and molybdenum, which is preferred for removing metals such as Iron, proving effective, is the hydrotreating catalyst can deactivate.

The reaction is expediently carried out at a pressure between 50 and 400 bar, preferably 150-250 bar. The liquid space-time velocity (LHSV) is, as has been shown by experiments, expediently at 1, however, under the circumstances it may of course deviate from it, depending on which Starting material and the desired products, the reactor dimensions, the catalyst, etc.

The invention is explained below using an example.

example

A reactor was built, which consisted of eight stainless steel tubes connected in series with pressure connectors through which each tube for charging and discharging the catalyst could be removed. The inner diameter of each tube was 8 mm and the entire length of the U-tubes and the connecting pieces that went into a fluidized bed was immersed was 20 meters. The first U-tube was with a protective catalyst made of 0.5% Co, 2.0% Mo on a 6.3 mm (1/4 inch) sphere carrier

^ -Aluminium loaded. The tubes 2 to 8 of the reactor were with a commercially available cobalt-molybdenum hydrogen cracking catalyst on an alumina support (comox 451, available from Laporte) in the form of 3.2 mm (1/8 inch) ■ pellets loaded,

^/:; ·· .νΟ "Ο λ- 3 1248 H

after the pellets had been calcined ^{at 550 ° C. for two hours.} The last 30 centimeters of the pipe 8 were also charged with a protective catalyst. The total volume of the Komox 451 catalyst was 853 cm (531 g)

3 and that of the protective catalyst 97cm (129g).

The tubular reactor was placed in a kettle, which was provided with external electrical heating devices and an air distribution base plate and which was sufficient Alundum grits (120 mesh, Norton Abrasives Ltd) were fitted to the top of the reactor overhead tubes cover.

The reactor was subjected to a sulfur pretreatment in which a 3 percent solution of carbon disulfide in hydrogenated anthracene oil was bubbled through the reactor for 24 hours.

The coal solution would be obtained by extracting a medium volatile bituminous coal in a hydrogenated anthracene oil, followed by filtering to nominally 20% coal in solution in the solvent containing 0.04% ash. The charcoal solution was in a heated, stirred Kettle stored and fed to the reactor by means of a high pressure pump. At the same time, hydrogen was on the same Pressure is compressed and the mixture of the solution and the hydrogen through the reactor under different conditions allowed to flow with the products collected and analyzed.

Temperatures during dec series of experiments were 376-443 ⁰ C, and the LHSV 0.4 to 1.8. The pressure fluctuated between 205 and 215 bar.

0.40 kg / h of the carbon solution were passed through the reactor together with 0.38 kg / h of hydrogen at a pressure of 215 bar, which was kept at an average temperature of 431 ^° C. The nominal LHSV was 0.5 h and the modified Reynolds number for the hydrogen was 269 and for the mixture 18, so that a laminar-turbulent change was observed through the reactor.

The analysis results are given below: E learn tar ana Iy s e:

Starting product

Light products

C% 90.4 88.7 H % 6.8 10.7 0% 1.7 0.3 N% 0.85 0.10 S ppm ND <50 H / C atomic ratio 0.90 1.45 nis ash 0.04 ND

Heavy products

89.9 9.6

<0.2

<0.10 <50 1.28

ND

ND = not determined

Boiling ranges (%)

1 BP - 170 ⁰ C 170 - 250 ⁰ C 250 - 300 ⁰ C 300 - 355 ⁰ C 355 - 420 ⁰ C + 420 ⁰ C

Starting product

2.4

7.8

36.4

25.6

27.8

Total liquid product 7.3

10.4 23.6 33.5 18.0 3.5

In general, it was found that a high conversion of the material with the high boiling point (> 420 ⁰ C) to a

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Material boiling below this temperature has been reached, with a conversion of 62% was increased to 89% when the temperature of 422 ⁰ C to 434 ⁰ C rising at an LHSV of 0.5; The yield of liquids which boiled below 250 ⁰ C, could be more than doubled by this temperature increase is more.

It was also found that the method according to the invention could result in a slate product in which a fraction was present in sufficient quantity to be considered Solvent to be recirculated to extract the coal at an LHSV of 1.0. In comparison tests with a conventional drop bed hydrogen cracking reactor An LHSV of 0.25-0.5 was required.

After 200 hours of operation, only one became very small deactivation of the catalyst noted, although carbon and iron deposition on the catalyst could be determined during a check.

Based on the results obtained, plan studies show that a charge of one tonne per hour of coal extract or hydrotreated oil in a reactor having an inner diameter of 15.2 cm (6 inches) and a length of 20 m while maintaining a non-streamlined flow.

Claims (6)

BROSED K "BROSE Diplom Ingenieure D-8023 Munchen-Pullach. Wiener Stf. 2; Tel. (Φ9) ί S3 30 71: Tele *" 5 2'2147 bros d: Cables- «Patentibus- Munich .x.: Λ: '"" ..,: * ■.:. 312A8T4 \ Tao: June 24, 1981 Date Your reference: t: Case 4255 '/ GER COAL INDUSTRY (PATENTS) LIMITED Hobart House, Grosvenor Place, London SW IX 7 AE, (Great Britain) Process for processing coal extract patent claims 1. A method for the catalytic hydrotreatment of coal extract or coal oil with an ash content of less than 0.1 percent, characterized gekennzeichn et that the extract or the oil passes through a tubular reactor which is not at a temperature of 350-450 ⁰ C and below under streamlined conditions is immersed in a bath of fluidized particles, the reactor containing a hydrotreating catalyst fixed bed, thereby providing precise temperature control and improved hydrogen cracking and / or hydrofining. 2. The method according to claim 1, characterized in that that the reactor is operated flooded or with a partially flooded, partially dripping bed. 3. The method according to claim 1 or 2, characterized in that the catalyst is a Co / Mo or W / Ni hydrogen cracking catalyst is. 4. The method according to claim 1, 2 or 3, characterized in that a protective catalyst in an initial treatment used to remove metals. 5. The method according to any one of claims 1 to 4, characterized in that the pressure in the reactor 50-400 bar, preferably 150-250 bar. 6. The method according to any one of claims 1 to 5, characterized in that the liquid period speed is about 1.