JPS59166587A - Coal purification - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to solvent refined coal (hereinafter also referred to as SRC).

According to the invention, in a two-step process, in a first step the coal is contacted with a solvent, whereby in a first reaction the coal is partially purified and some of the solvent removed, and in a second step a A method for purifying coal is provided that includes leaving partially purified coal from a first step in contact with residual solvent to further purify the coal in two reactions.

The method of the present invention may include removing at least some residual solvent after the second reaction, thereby producing solvent purified coal.

The solvent can be an oil. Oil is about 0℃~about 450℃
It can be an oil fraction derived from coal having a boiling point range of from about 00°C to about 45°C (1°C), for example.

The ratio of oil-sealed coal in the first step is about 1:1 to about 5 on a mass basis
=1, preferably 2:1, so that in the first step the oil and coal are in the form of an oil/coal slurry.

The method of the present invention can include adding a catalyst to the slurry. The ratio of catalyst to coal in the slurry in the first step may be about 1=50 on a mass basis. The catalyst is preferably a metal-based catalyst.

The contact in the first step is carried out at a temperature of about 50°C to about 480°C, e.g. about 400°C to 450°C, and about 5 x 10"kPa.
~about 30 X I Q3kPa1 e.g. about 20
This is preferably carried out at a pressure of X 103 kPa. The reaction is preferably carried out in a hydrogen-rich atmosphere. The reaction time of the first reaction is 2
It can be less than 0 minutes, such as about 10 minutes or less.

Oil removal can be accomplished by distillation.

The volume of oil to be distilled off is determined by the fact that the oil and coal residue are still in the form of a slurry in the second step, and the concentration of catalyst in the slurry in the second step is greater than the concentration of catalyst in the slurry in the first step. The amount should preferably be at least twice as large.

The contacting in the second step is also at a temperature of about 50°C to about 480°C, such as about 400°C to 450°C, and about 5 x 103
kPa to about 30 X I Q3kPa, for example about 2
It can be carried out at a pressure of 0 x l Q3kpa.

The reaction time in the second step can be about 15 minutes to about 150 minutes.

The invention also extends to solvent purified coal when made by the method described above.

The invention is now illustrated by the following non-limiting examples.

Example 1 1. Pulverized bituminous coal containing 136% persimmon content and 10% ash by weight, oil fraction (solvent) derived from the coal having a boiling point range of about 00°C to about 420°C 2
It was made into a slurry by weight. This slurry 1500y,
5I! The reaction was carried out in an autoclave with 2% by weight of Fe203 based on coal as added catalyst. In the first step,
Coal is heated approximately 20X with solvent in a hydrogen-rich atmosphere for 10 minutes.
The coal was partially purified by contacting at a pressure of IQ3 kPa and a temperature of 425°C. Sufficient solvent was then distilled off until a slurry remained in the fang-tralepe with a catalyst concentration that was approximately three times greater than the catalyst concentration in the slurry of the first step. The partially purified coal (i.e. coal residue) is now heated to a temperature of 425°C and about 2
It remained in contact with the residual solvent for a further 120 minutes in a second step at a pressure of 0X I Q3 kPa. The autoclave was then cooled and the contents treated to recover solvent-purified coal (e.g., to remove unreacted products and recover distillable oil).

1.2 Slurry 15005' of 1.1 was re-reacted in a 51 autoclave with 2 wt% Fe2O3 on coal as added catalyst. The reaction conditions were the same as the first step in 1.1. However, the reaction time in the first step was increased to 130 minutes, after which the solvent was not distilled off, ie the second step was not performed.

Comparison of products obtained from 1.1 and 10.2 above (
(calculated as net weight % based on dry ash-free coal)
was as follows.

Experiment 1,1 Experiment 1.2 GO+GO23,12,0 H208,07,2 C1~C38,211,7 C4~200℃ 14,1 25.9200
~420℃ 16,0 17.9SRC (42
0°c+) 42,2 67.9 Insoluble
2.3 3.2 SR obtained from both experiments
C was coked at 500°C (5 hours heating time and 4 hours coking time) and beach baked at 1370°C for 30 minutes.

The coefficient of thermal expansion of coke that had been burnt to a minimum was measured using an X-ray diffraction method. The coefficient of thermal expansion (CTE) was 0.4X10-6 for the calcined coke obtained from experiment 1.1 and 0.7X10-' for the Trt-baked coke obtained from experiment 1.2. Met.

From the above results, it can be seen that coke of excellent quality can be obtained from the two-step method of the present invention. This two-step process is self-sufficient in terms of solvent requirements. Run 1.2 gave inferior quality coke and was severely deficient in processing solvent.

Example 2 The slurry IJ-1500Y of Example 1 was again reacted with 2% by weight of coal-based FC203 in a 51 autoclave as an added catalyst. Approximately 2Q of coal is used in the first process.
x l 10 at a pressure of 03 kPa8 and a temperature of 425 °C
The solution was contacted with the solvent in a hydrogen-rich atmosphere for minutes. Sufficient solvent was then distilled off until a slurry remained in the autoclave having a catalyst concentration that was approximately three times greater than the catalyst concentration of the first step slurry. The temperature of the autoclave was increased to 445° C. and contact continued for an additional 60 minutes in a second step at a pressure of approximately 20×10” kPa.

The following product spectrum was obtained (calculated as a net mass of 96 based on dry ash-free coal).

Co + Co□ 2.4H708,5 C1~G313.2 04~200℃ 20.9 200~420℃ 14.4 srtc (420℃+) 385 Not dissolved
2.2 Teriyaki coke was made from SRC in the same manner as in Example 1, which was of high quality with a CTE value of 0.4 (C6~200℃ and 20℃ respectively)
0-420°C) to produce a 35% liquid product.

(10'Example 3) The slurry IJ-15009 of Example 1 was treated with coal based catalyst as catalyst under the same first and second steps as described above for Example 2 and under the same reaction conditions as Example 2. % by weight of FC203 in a 5I! autoclave. The only difference was that the reaction time in the second step was increased from 60 to 120 minutes, which increased the production of liquid fuel. .

The following product spectrum was obtained (calculated as % net weight based on dry ash-free coal).

Go + Co22.7 H2O2,6 C1~Cs 13.5 04~200℃ 20.4 200~420℃ 17.3 SRC (420℃+) 35.3 Not dissolved
24 The total yield of liquid product was 37.7%, while SRC
The CTH of γN-baked coke made from
) It was 10-6.

Example 4 The slurry 1500y of Example 1 was again used, to which was added 2% by weight of Fe2O3 based on coal as an added catalyst. Both the first and second steps were performed in a continuous flow reactor. For the first step a 11 autoclave was used; for the second step a vertical open tube reactor with a diameter of 25 πm was used. The reaction time was 15 minutes in the autoclave and 120 minutes in the open tube reactor.

The contact temperature and pressure for both steps were 425° C. and 20×I Q”kPa, respectively. The following product spectra were obtained (calculated as % net mass based on dry ash-free coal).

CD 10 Co22.8 H2° 10.0 C1 to C38,4 C4 to 200°C 19.3 200 to 420°C 20.3 SRC (420°C) 378 Undissolved 1.4 0.4 from the above SRC A burnt coke with a CT'E value of ' was produced.

The 200-420° C. fraction recovered after the first and second steps can be recycled (ie, used to form a slurry for the first step). Excess oil can be used elsewhere, for example, it can be upgraded into diesel oil.

The inventors have found that SRC, which is a solid pitch-like material under ambient conditions and conventionally usually obtained by direct hydrogenation of coal, can be used as a feedstock for making coke by the sylate coking process. The green coke thus produced can be terilized and then used to make electrodes.

The quality of the electrodes is highly dependent on the degrafting of the original or raw material coal used.

There are methods of depolymerizing coal that involve solvation of the coal with a solvent in a single step. During solvation, coal is depolymerized, but coal fragments have a strong tendency to combine with fragments or solvent molecules in side reactions, thus creating a shortage of recycled solvent. To prevent or reduce the occurrence of these undesirable (,13) side reactions, good catalyst systems and high hydrogen pressures are commonly used.

The prolonged reaction times required to reduce the foreign atom content under these conditions result in high yields of liquid and gaseous products and thus low yields of solid SRC. On the other hand, if short reaction times are used to maximize SRC production, the product still contains too high a foreign atom content, making it suitable for producing high quality electrode coke.

During the depolymerization reaction, gases such as hydrogen sulfide, carbon dioxide, -carbon oxide, ammonia and water are evolved, indicating that heteroatomic sulfur, nitrogen and oxygen are liberated from the coal molecules during depolymerization.

Without wishing to be bound by theory, the inventors believe that foreign atoms in the molecular structure of the coking feedstock induce its graphitization at high temperatures by increasing its viscosity and reducing the plasticity range of the mesophase. I believe that it will interfere (J Dubo
is, CAqacbe and J.L. White, Metallography Vol. 3, pp. 337-360, 19
(see 1970). Water C14) elemental cracking is therefore required to reduce the foreign atom content of the solvent-purified coal as much as possible.

N+S 10 U.S. Pat. No. 4,210,51.7 shows that the ratio of %--1 is correlated with the quality of the coke subjected to rFL baking, with the lowest value corresponding to good quality coke. Ta. This again shows that the base pitch must have a low foreign atom content (and a high carbon content).

In known methods either low yields of good quality SRC or high yields of poor quality SRC are obtained.

The present invention thus provides a two-step process in which the side reactions described above are minimized or reduced as a result of removing some of the solvent of the first step. The reaction conditions are modified to provide (1) self-sufficiency as seen in high yields of high quality (i.e., low outmoded atom content) and solvent requirements, or (II) high quality SRC with high yields of liquid products. can be selected to give a low yield of (
15) Believe. SRC is suitable for producing high quality electrode coke.

Additionally, without the use of added metal-based catalysts (i.e., utilizing only the natural catalytic activity present in the coal), the two-step process of the present invention provides self-sufficiency and high quality as seen in solvent requirements. I believe it is possible to obtain a large amount of SRC. However, when using metal-based catalysts (in which case higher reaction temperatures and shorter reaction times can be utilized to obtain similar product spectra), the same degree of self-sufficiency as seen in solvent requirements and the effects of high quality SRC The same amount can be obtained. By using metal-based catalysts and by varying the reaction conditions of the first and second steps, the amount of liquid product obtained can be varied.

The method of the present invention allows the use of lower initial catalyst concentrations when compared to the known methods described above, allowing lower overall catalyst usage than is possible with the known methods described above.

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Claims (1)

[Claims] 1. In a two-step process, the coal is brought into contact with a solvent in the first step, thereby partially refining the coal in the first reaction,
removing some of the solvent and leaving the partially purified coal from the first step in contact with the remaining solvent to further purify the coal in a second reaction in a second step. Characteristic coal refining method. 2 removing at least some residual solvent after the second reaction;
The method according to claim 1, wherein solvent-purified coal is produced by this method. 3. The method according to claim 2, wherein the solvent is oil and the coal is in pulverized form. 4. The method of claim 3, wherein the oil is an oil distillate derived from coal having a boiling range of about 0°C to about 450°C. 5. The oil to coal ratio in the first step is from about 1:1 to about 5:1 by weight, such that the oil and coal are in the form of an oil/coal slurry in the first step. or the fourth
The method described in section. 6. The method of claim 5 comprising adding a catalyst to the slurry. 7. The method according to claim 6, wherein the ratio of catalyst to coal in the slurry in the first step is about 1=50 on a mass basis. 8. The method according to claim 6 or 7, wherein the catalyst is a metal-based catalyst. 9. Temperature of about 50° C. to about 480° C., and about 5× ] 03 kPa to about 30×10
A method according to any one of claims 6 to 8, which is carried out at a pressure of 3 kPa. 10. The method according to any one of claims 6 to 9, wherein the first reaction is carried out in a hydrogen-rich atmosphere and the reaction time of the first reaction is less than 20 minutes. 11. The method according to claims 6 to 10, wherein the oil is removed by distillation. 12. The volume of oil distilled off is such that the oil and coal residue in the second step are still in the form of a slurry, and the concentration of catalyst in the slurry in the second step is greater than that of the catalyst in the slurry in the first step. 13. The method of claim 11 in which the concentration is lower (both twice as high). 30 x 103
The method according to claim 11 or claim 12, which is carried out at a pressure of kPa. 14. The method of claim 13, wherein the reaction time in the second step is about 15 minutes to about 150 minutes.