JPS63238197A - Liquefaction of coal - Google Patents

Abstract

PURPOSE:To secure liquid yield and a solvent for coal liquefaction regardless the kinds of used coal and contrive safety operation of a process, by adjust the toluene soluble content in distillation residue produced in a distillation process to a specific amount, when a plural coal mixture is liquefied. CONSTITUTION:Two or more kinds of coals are blended and subjected to liquefaction reaction, preferably at 430-470 deg.C for 0.5-2.0hr in 100-200atm. hydrogen pressure using an iron based catalyst (containing cocatalyst) while adjusting toluene soluble content in a distillation residue produced in a distillation process to >=20%. The distillation residue having good flowability regardless of the used kinds of coal is obtained by the adjustment.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of operating a liquefaction step and a distillation step in a coal liquefaction process.

(Prior art and its problems) The coal liquefaction process includes a liquefaction reaction step to liquefy coal, a distillation step to separate the liquefied product into liquefied oil and residue,
It consists of a solvent hydrogenation process in which hydrogen is added to liquefied oil to reform it into a liquefied solvent.

In the liquefaction reaction step, a solvent containing coal and coal liquefied oil as main components and a catalyst that promotes the liquefaction of coal are supplied.
Liquefaction is carried out by holding at a high temperature of about 400 to 500° C. for about 0.5 to 2.0 hours under hydrogen pressure of about 300 atm.

In the distillation process, the liquefied product is distilled after gas, raw material hydrogen, etc. have been separated, and light oil (BP; IBP ~ 200 ° C.
), medium oil (BP; 200-350℃), heavy oil (BP;
350 to 538°C) is extracted from the top of the distillation column, and distillation residue is extracted from the bottom. In the solvent hydrogenation process, hydrogen is added to medium oil and heavy oil using a high-grade catalyst (for example, Ni-Mo/A 1 , O,), and the oil is modified to have properties suitable as a solvent for coal liquefaction. .

It is desired that such a coal liquefaction process be applicable to all types of coal, since its construction costs are high and it is difficult to secure a large amount of raw material coal for one type of coal.

In addition, in the coal liquefaction process, it is important to ensure the separation of distillation residue during the distillation process and ensure stable operation of the process.
It is equally important to improve the liquid yield in the coal liquefaction process.

In other words, when coal is liquefied using a known process with a cut temperature of 538°C in the distillation column, the distillation process is stable when liquefying coal that has a low ash content and produces a large amount of distillation residue; When liquefying coal, which produces a small amount of coal, ash concentrates in the distillation residue during the distillation process, reducing the fluidity of the distillation residue, making it difficult to extract it from the bottom of the distillation column, and hindering the stable operation of the liquefaction process. There is a problem.

As a method to solve this problem, a method can be considered: (1) to remove ash in advance from coal that has a high ash content and produces a small amount of distillation residue. However, this method has the following drawbacks.

(a) Since deashing equipment is required that has a processing capacity greater than the amount of coal required for the coal liquefaction process, its construction and operating costs are high.

(b) Ash, which has the effect of promoting coal liquefaction, must be removed in advance, and a new catalyst must be added.

In addition, it is possible to remove ash in advance by methods such as solvent extraction, centrifugation, supercritical extraction, and addition of anti-solvents prior to the distillation process, but this method requires new equipment and the construction cost. , operating costs are high.

In addition, as a known liquefaction method in which two or more types of coal are mixed, a method that aims to improve the liquid yield (Japanese Patent Laid-Open No. 58-18929
2) Method for securing raw material solvent (Japanese Patent Application Laid-Open No. 52-14
5400), Method for reducing viscosity of raw material slurry (JP-A-57-170985, JP-A-58-185684)
There are various methods, but they have advantages and disadvantages, and none of them solves the above problems.

As described above, it has been difficult to liquefy coal with high ash content and little distillation residue using conventional operating methods.

(Objective of the Invention) The object of the present invention is to achieve stable operation of a coal liquefaction process, particularly a distillation process, regardless of the type of coal used.

(Structure of the Invention) In coal liquefaction using a mixture of two or more types of coal, the present inventors
■The fluidity of the distillation residue produced is closely related to the toluene soluble content in the distillation residue, and as the amount of toluene soluble content increases, the fluidity improves.

■This relationship holds true regardless of the amount of coal or reaction conditions.

■We found that additivity exists between the liquefaction reactivity of two or more types of coal and the properties of the distillation residue.

The gist of the present invention is to mix two or more types of coal and liquefy it, and reduce the amount of toluene soluble content in the distillation residue produced in the distillation process to 20%.
This is a method for liquefying coal, which is characterized by adjusting the coal content to % or more.

The reaction temperature, reaction time, hydrogen pressure, liquefaction catalyst, etc. in the liquefaction process are not particularly different from known methods. Preferred conditions are a reaction temperature of 430-470°C and a reaction time of 0.5-470°C.
The hydrogen pressure is approximately 100 to 200 atm for 2.0 hours.

As the liquefaction catalyst, it is preferable to use an inexpensive iron-based catalyst in combination with a promoter (sulfur compound).

In the present invention, two or more types of coal are mixed and liquefied, and the amount of toluene soluble content in the distillation residue produced in the distillation process is reduced to 20%.
Adjust so that the above is achieved. By this adjustment, a distillation residue with good fluidity can be obtained regardless of the type of coal used. The amount of toluene soluble content is preferably 20% or more, and if it is less than 20%, fluidity will be insufficient.

(Example) Next, the present invention will be explained by examples.

(Left below) Coal shown in Table 1 was liquefied using coal liquefaction equipment having a processing capacity of 5 J2/h. The operating conditions are shown in Table 2.

Gas and hydrogen are removed from the product after the liquefaction reaction, and the
It was distilled under reduced pressure and separated into a distillate oil with a boiling point of up to 538°C and a distillation residue.

Figure 1 shows the relationship between the softening point of the distillation residue obtained by liquefying various types of coal and the toluene soluble content in the distillation residue.

From FIG. 1, it is recognized that as the toluene soluble content in the distillation residue increases, the softening point of the distillation residue decreases. Moreover, it is recognized that this relationship holds regardless of the coal type and liquefaction reaction conditions. Therefore, by increasing the toluene soluble content of the distillation residue produced during the coal liquefaction process to 20% or more, the fluidity of the distillation residue can be improved and safe operation can be achieved.

Next, add Buddle River charcoal and River King charcoal to the third
Each was liquefied under the operating conditions shown in the table, and the material balance and properties of the obtained distillation residue are shown in Table 4 as a comparative example.

(Margins below) Table 4 (Comparative Example) In addition, Figures 2 and 3 show the results of liquefying mixed coal of River King coal and Buddle River coal at different mixing ratios as an example. From FIG. 2, it is recognized that additivity is established in the material balance when two types of coal are mixed and liquefied. Moreover, from FIG. 3, it is recognized that additivity is also established in the properties of the distillation residue obtained by mixing and liquefying two types of coal.

Compared to the case of using only Buddle River charcoal in Table 4, the second
As shown in Fig. 3, when two or more types of mixed coal are used, more stable operation is possible.

(Effect of the invention) According to the present invention, the following effects are produced.

■Regardless of the type of coal used, liquid yield and solvent for coal liquefaction are ensured, ensuring stable operation of the process.

■Compared to the case of pre-deashing, special treatment equipment is not required.

■ Ash, which has the effect of promoting coal liquefaction, can be supplied to the liquefaction process, which is effective in reducing the amount of catalyst used.

■The entire amount of raw coal can be supplied to the liquefaction process.

[Brief explanation of the drawing]

FIG. 1 shows the relationship between the softening point and toluene soluble content of distillation residues obtained from various types of coal. Figure 2 shows the mass balance when the mixing ratio of River King coal and Buddle River coal is changed. FIG. 3 shows the properties of the distillation residue when the mixing ratio of River King charcoal and Buddle River charcoal is changed.

Claims (1)

[Claims] A method for liquefying coal, which comprises mixing and liquefying two or more types of coal and adjusting the amount of toluene soluble content in the distillation residue produced in a distillation process to 20% or more.