JPS6063283A - Coal liquefaction - Google Patents

Abstract

PURPOSE:An aqueous solution of compounds containing Sn and Zn is added to a coal slurry as a catalyst, then coal liquefaction is carried out with high-pressure hydrogen to achieve high-efficiency liquefaction of coal with a small amount of the catalyst, whereby inexpensive liquefied oil is obtained in high yield. CONSTITUTION:First, a solution of compounds containing Sn and/or Zn, preferably potassium stannate, in water or an organic solvent, as a catalyst, is added to a slurry of coal in a solvent, then the slurry is brought into contact with hydrogen under high-temperature and high-pressure conditions to liquefy the coal. The above reaction is effected usually at 100-300 atmospheric pressure and 400-480 deg.C.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a method for direct hydrogenation and liquefaction of coal, and in particular to a catalyst suitable for reacting coal slurry and hydrogen in a short time to obtain a large amount of liquid. , and its addition method.

[Background of the invention]

Many studies have been conducted on coal liquefaction methods, and these can be roughly divided into (1) direct hydrogenation and liquefaction methods;
There are four methods: 2) extraction hydrogenation liquefaction method, (3) synthetic liquefaction method, and (4) dry distillation liquefaction method.

Technically, method (3) is the most advanced, but it requires at least a two-step process of gasifying the coal and then liquefying it again, resulting in high product costs and low overall yields. (4
) is the simplest process, but it has the lowest yield, still produces a large amount of solids (char), and has processing problems. , (2) is a method of liquefying with hydrogen in a solvent without using high-pressure hydrogen, but the liquefied oil is heavy and has low utility value, and only certain types of coal can be used, and There are jlQ points during which the solvent must be reused by hydrogenation treatment, etc.

On the other hand, (1) is a method in which coal slurry is mixed with hydrogen under high pressure and heated to a reaction temperature of 911 degrees through a preheating step.

Catalysts are used to improve the yield of liquefied oil, but depending on the catalyst, there are two methods: (5) using a large amount of inexpensive catalyst with low catalytic activity, and (+3) using a relatively expensive catalyst with high catalytic activity. It is divided into two parts depending on the method used.

Since the catalyst is cheap, it can be disposed of, but it has drawbacks such as low activity, heavy liquefied oil, low utilization filli value, and frequent generation of residue, which poses problems in its disposal. With 03), the activity of the catalyst decreases quickly, so in order to maintain the liquefaction rate, it is necessary to replenish or replace the expensive catalyst. Therefore, it is necessary to select a highly active catalyst in a small amount and to efficiently recover the catalyst. There are always problems when you have to do it.

[Purpose of the invention]

An object of the present invention is to provide a catalyst that exhibits high catalytic activity in a small amount in a direct hydrogenation liquefaction method, and a coal liquefaction method in which the catalyst is mixed into a coal slurry so that it exhibits the highest activity in a reactor. .

[Summary of the Invention] Coal liquefaction methods can be roughly divided into four types as mentioned above, but the direct hydrogenation method is considered to be the most promising in the future in terms of the overall cost of the process and the quality of liquefied oil. . In the direct hydrogenation method, a slurry of coal and a solvent is mixed with hydrogen at 100-30%
Coal is reacted under high temperature and high pressure conditions such as 0 atm and 400 to 480C to reduce its molecular weight, and is dispersed in a solvent to form an ashless liquid from the unreacted coal containing ash. It's a method. At this time, the necessary hydrogen can be obtained by gasifying the separated unreacted carbon content or reforming the by-product gas.

In the direct hydrogenation method, a catalyst is added to the liquid to increase the proportion of light oil in the liquefied oil. There are two types of IN+ hv: an inexpensive disposable catalyst and a high-grade catalyst with high catalytic activity (13).
In order to obtain a large amount of light oil, it is desirable to use 0°. However, since the catalyst activity of (B) is significantly reduced, it is necessary to recover the expensive catalyst and reuse it by converting it into acid or V. However, since there is a limit to the recovery rate, there is a need for a catalyst and a method for adding the catalyst that can provide an excellent liquefaction rate even with a small amount added.

One method for this is to reduce the amount of catalyst added by mixing the catalyst in the form of fine powder into the slurry and recycling some of the unreacted carbon after the reaction to reuse it as a catalyst (
JP-A-53-106709). In this method, a water-soluble compound such as ammonium molybdate is used as a highly active catalyst, and the aqueous solution is dispersed as an emulsion in a coal slurry, and the reaction is carried out in the form of fine powder of molybdenum oxide in a reaction atmosphere. method is known. This is thought to be because molybdenum oxide becomes finer particles than when it is added as a powder, so the surface area of the catalyst becomes larger, and a smaller amount of molybdenum oxide exhibits the same level of catalytic activity. Therefore, if we can find a catalyst with higher activity using this method, we believe that the liquefaction rate can be maintained with a smaller amount of catalyst added, and the cost of liquefied oil can also be reduced.As a result of various studies, we have arrived at the present invention. .

Chlorides of tin and zinc are known as high-grade catalysts with high catalytic activity. These melt and become liquid under the reaction conditions, and since the active surface is constantly renewed, no reduction in activity occurs, and liquefied oil with a high light oil content can be obtained in high yield. However, at the same time, there were problems with equipment corrosion due to the hydrogen chloride and recovery of the catalyst. Therefore, the present invention was achieved by considering whether it is possible to create a state similar to the molten state under reaction conditions by using highly active compounds of tin and zinc without using chlorides. That is, water-soluble or organic solvent-soluble tin and iIF lead compounds are mixed into coal slurry as a solution in water or an organic solvent, and are made into fine powder in a reaction atmosphere so that they exhibit high liquefaction activity even in a small amount. [Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be explained using the 1''!11 plane.

Coal 1 pulverized to 0.1 mm or less is supplied from a hopper 2 to a mixer 3 in fixed quantities. In mixer 3, circulating solvent 25
and an aqueous solution 4 of tin or zinc are mixed and stirred to form a coal slurry 5 in which the aqueous solution 4 is dispersed as an emulsion. The coal slurry 5 is pressurized by a pump 6, mixed with hydrogen 32 which is similarly pressurized by a compressor 31, and mixed with hydrogen 32 by a preheater 7.
Preheat to about 50C. 400 ~ in reactor 8. p
The coal is heated to 480PC and reacted with hydrogen while stirring to liquefy the coal. The crude product 9 produced by the reaction contains gas, liquid matter, unreacted coal, ash, etc., so it is separated in the high-pressure gas-liquid separator 10 by hydrogen, by-product gas, light oil, heavy oil, etc.
Separate into unreacted carbon and ash. The gas and light oil are further passed through an atmospheric distillation column 11 to hydrogen and by-product gas 12,
It is separated into a product oil 13 and a distillation residue 14. Hydrogen and by-product gas 12 are subjected to cryogenic separation, etc., and then sent to reforming tower 15.
Steam 16 is blown into the hydrocarbon gas component to perform steam reforming to produce reformed hydrogen 17, which is reused together with unreacted hydrogen as hydrogen for the 7 shallowing reaction. High pressure gas/liquid minute R?
Heavy oil, unreacted coal, ash, etc. separated with 1ylO are subjected to solid-liquid separation using a method such as Hydroclone 18.
Divided into medium/heavy oil 19, unreacted coal, ash, etc. l'li
&do. The medium/heavy oil 19 is mixed with the atmospheric distillation residue 14 and separated into medium oil 22, heavy oil 23, and tar pitch 24 in a vacuum distillation column 21. Heavy oil 23 and tar
A portion of the pitch 24 and the vacuum distillation residue are mixed and reused as a coal solvent 25. Unreacted coal and ash are gasified in a 20-car gasifier 26 using oxygen and steam 33 to form gasified hydrogen 27 and ash 28.

Unreacted hydrogen, reformed hydrogen 17, and hydrogen scum 27 are combined to form hydrogen for liquefaction 29, but if the amount of hydrogen is small, supplementary hydrogen 30 is separately supplied.

Table 1 shows the results of a comparison of the coal liquefaction performance of God's Catalyst using a batch type reactor as a basic experiment directly to the device shown in the figure above.

Batch reaction tests include coal, solvent, and 7! II was placed in a reaction vessel in advance, then filled with hydrogen, and the heated melt (
The reactor is immersed in solder, rapidly heated and shaken, and then rapidly cooled after a certain period of time, after which the product is collected. Table 1 shows the type of 1111t medium, catalyst addition M to coal, hydrogen pressure, pJH straining rate, time, conversion rate of liquid in the product, light oil yield, and heavy oil yield. (hereinafter referred to as L/H). Comparing Flat 6 with no catalyst added and other results, the conversion rate and L/H were higher when the catalyst was added, indicating that these catalysts had an effect on the production of liquid products. I can tell when it's there. Looking at the catalyst activity, iron oxide and water rli adsorption properties are low, and the conversion rate hardly increases even when 5% is added, but the conversion rate increases significantly with other highly active catalysts. In particular, the effect of the water-soluble or organic solvent-soluble tin-based catalyst of the present invention is high, and both the clam formation rate and L/H are high.

When the amount of catalyst is as small as 0.5 W, the conversion rate and L/H decrease with any catalyst, but powdered tin oxide (Sn
02), water-soluble potassium stannate (K2Sn02) and ammonium molybdate (
(NH4)s Moy 024 ) did not decrease much. Especially in the case of potassium stannate, O,
(Even if the addition amount was reduced to 15 W t%, rn< , the same results were obtained as when ammonium molybdate was added at 0.5 W t%, indicating that the catalyst shows a high liquid yield with a small amount. I found out.

-4 Table 2 shows the reaction iMP1i4 s o c and 43D using the reaction system shown in Figure 1 based on the results in Table 1.
Show the results when the reaction was carried out in C. Even if the reaction temperature is lowered, the conversion rate and L/H do not change much.

Looking at the activity of the catalyst, potassium stannate was added at 0.05 Wi%.
It shows a high conversion rate and L/H even when adding .

When 0.5 Wt% of frozen potassium stannate was added, the conversion rate, L/H, was higher than when the same amount of tin oxide was added and the reaction was carried out at 450C. From this, it is possible to alleviate the reaction to the incident.

This result is an example of an aqueous solution of a tin compound, but as can be seen from Table 1, a similar tin-based compound, tetraphenyltin (S L' (C6115)4)
IE lead acetate (Zn(CH3C
Even when the aqueous solution of OO)2) is reacted with the same amount of potassium stannate aqueous solution, it shows a higher conversion rate, L/H, than the conventional aqueous ammonium molybdate solution. Therefore, when the compound of tin or zinc of this → Ramei is used as a solution in water or an organic solvent, compared to a solution of a conventional molybdenum compound or a catalyst made of a tin or zinc body, the amount of
4 can achieve high liquid yield.

It was assumed that the cause of this was that the catalyst liquid was dispersed as an emulsion in the coal slurry, turned into fine powder in the reaction atmosphere, and was uniformly distributed on the coal, but in reality, tin and zinc in unreacted clay were found. Comparing the distribution state of tin with that when powdered oxide was added, it was found that when oxide was added, tin was unevenly present in the unreacted clay (there were many hollow spots). When the solution was added, f:i was distributed almost uniformly, and it became clear that this was a factor in increasing the yield of the liquid product.

〔Effect of the invention〕

According to the present invention, a compound containing tin and/or zinc as a catalyst is added as a solution of water or a Buddhist solvent to a slurry of coal and a solvent, and a coal liquefaction reaction is carried out using high-pressure hydrogen. A solution of a molybdenum compound can yield a bright liquid product even with a smaller amount of catalyst than a powdered catalyst.

[Brief explanation of the drawing]

The drawing is a process flow sheet showing the coal power attraction method of the present invention. 1...Supplied coal, 3...Mixer, 4...River: I
/lL solution, 8... reactor, 10... gas-liquid separator,
II... Atmospheric pressure distillation column, 15... Modifying group, 17...
Reformed hydrogen, unreacted hydrogen, 18...solid-liquid t111 unit,
21...7 Compressive distillation column, 25... Circulating solvent, 26...
... Gasifier, 27... Gasified hydrogen, 30... Replenishment hydrogen, 32... Pressurized hydrogen. Agent Patent Attorney Tatsuyuki Unuma

Claims (1)

[Claims] 1. A coal liquefaction method in which coal is liquefied by contacting a slurry of coal mixed with a solvent and a catalyst with hydrogen under high pressure. A coal liquefaction method characterized by using a bath solution in which a compound containing 1F lead is dissolved in water or an organic solvent, and adding this solution to a slurry for reaction. 2,! 1. A method for liquefying coal according to claim 1, characterized in that the tin compound as a catalyst is potassium tin.