JPS5956487A - Two-step liquefaction of coal - Google Patents

Abstract

PURPOSE:To make the conditions of cracking of solubilizable components into light components coincide with those of hydrogenation with effective ingredients of solent, by dissolving coal in a solvent for separation of oil component and heavy component and performing hydrogenation by feeding the heavy component into the 1st reactor of a reaction zone consisting of two or more reactors and feeding the heavy component midway into the reaction zone. CONSTITUTION:Coal is dissolved, under heating, in a solvent consisting of partially hydrogenated bi-quinque-cyclic aromatic hydrocarbon. The solution is distilled and separated into an oil component with a boiling point of 400-500 deg.C and a heavy component with a higher boiling point. For hydrogenation treatment, the heavy component is fed into the 1st reactor of a reaction zone consisting of two or more reactors under the same pressure arranged in a series and the oil component is fed midway into the reaction zone.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coal liquefaction method, and in particular, a first reaction step in which a solvent and coal are mixed and heated to solubilize the coal, and the first reaction step product is treated with a catalyst and a gaseous state. The present invention relates to an improvement in a two-stage liquefaction method comprising a second stage reaction step of hydrogenation in the presence of hydrogen.

In recent years, with the diversification of energy sources, the development of coal liquefaction processes has been accelerated, and numerous studies are being conducted.

Among them, the two-stage liquefaction method involves first solubilizing coal under relatively mild conditions using the ability of a solvent, and then using a catalytic action to decompose and lighten the solubilized components in the presence of hydrogen. ,
This is an excellent method because it reduces hydrogen consumption and increases the degree of freedom for product diversification.

On the other hand, in the two-stage liquefaction method, since the first stage reaction is controlled by the ability of the solvent, an important issue is how to maintain the properties of the solvent.

In the first stage reaction, coal is thermally decomposed under high temperature conditions and converted into polymeric components called pre-asphaltenes and asphaltenes, which are then solubilized. The radicals generated during this thermal decomposition receive hydrogen from hydrogen-donating solvents and/or hydrogen-rich parts of the coal, and the solvents that are likely to readily transfer hydrogen (this phenomenon is called the solvent shuttling effect). (Polycyclic aromatics are said to have this effect.)
It is thought that it absorbs hydrogen and stabilizes it.

Therefore, the solvent supplied to the first stage reaction must be a solvent with excellent functions as described above. If not, the active pre-asphaltenes and asphaltenes generated by thermal decomposition will recombine and be extremely difficult to decompose. It will be converted into a macromolecule.

As a high-quality solvent that meets the above conditions, the inventors
Other researchers have also mentioned partially hydrogenated polycyclic aromatic compounds having 2 to 5 rings. Therefore, the success or failure of the two-stage liquefaction method depends on how to rationally produce this solvent within the coal liquefaction process.

In order to produce partially hydrogenated polycyclic aromatics, polycyclic aromatics are treated with catalysts (e.g. nickel/molybdenum, cobalt/
Hydrogenation may be carried out in the presence of a molybdenum-based catalyst] and gaseous hydrogen;
This is a high-temperature, high-pressure reaction of Kg/cfG or more, and requires a high-pressure reactor, as well as a compressor 9 to supply hydrogen under high pressure.A device to recover and circulate excess hydrogen from the reaction, and supply raw materials under high pressure. Various peripheral equipment is required, such as a pump to heat the reaction liquid and a device to separate the heat from the gas and reduce the pressure at the same pressure.

In addition, since the solvent/coal ratio in the first stage reaction process is 15 to 3.0, the amount of solvent handled is 1.5 to 3.0 times the original amount of coal processed. construction cost,
This will account for a significant portion of operating costs.

-1+, there is also a conventional method in which the solvent component is simultaneously hydrogenated in the second reaction step for decomposing and lightening the solubilized coal in the presence of a catalyst and hydrogen.

In this case, the major problem lies in the fact that the conditions for decomposing and lightening the solubilized material and the conditions for appropriately hydrogenating the active components of the solvent do not match. In other words, the decomposition and lightening conditions for the solubilized material are more severe than the hydrogenation conditions for the active component of the solvent, so if the conditions are made to mainly decompose, the active component of the solvent will be overhydrogenated, and the solvent capacity will be extremely reduced. If the solvent is mainly hydrogenated, the decomposition rate will be insufficient.

The present invention proposes two new types of coal that overcome the drawbacks of the above-mentioned conventional methods.
This is a stage liquefaction method, which provides a method for rationally performing decomposition and lightening of coal solubilized materials and appropriate hydrogenation of the effective components of the solvent within the second stage reaction process.

That is, the present invention is a coal liquefaction process that consists of a first reaction step in which coal and a solvent are mixed and heated to solubilize the coal, and a second reaction step in which at least a part of the product of the first step reaction step is hydrotreated. In this method, the product of the first stage reaction step is separated into an oil component with a boiling point of 400 to 500°C or less and a heavy component with a boiling point higher than that, and the second stage reaction step is carried out in multiple stages with substantially equal pressure and , a two-stage coal coal production system comprising reaction zones connected in series, wherein the heavy component is supplied from the first of the plurality of reaction zones, and the oil component is supplied from the middle of the plurality of reaction zones. The gist is the liquefaction method.

According to the present invention, first, the mixture containing the solvent component produced in the first reaction step is distilled to a boiling point of 400 to 500°C.
It is separated into the oil component below and the heavy component with a boiling point higher than that. In this case, the distillation cut temperature should be set so that the active ingredients as a solvent (hydrogenated polycyclic aromatics and non-hydrogenated polycyclic aromatics) are recovered in the oil, but items 4 and 5 should be set. The range is preferably 400 to 500 from the boiling point of the aromatic ring.

Next, the second stage reaction step is composed of a plurality of reaction zones connected in series with substantially the same pressure, and the heavy component is supplied from the first reaction zone, while the oil component is supplied from the middle.

By feeding the heavy components and oil components separately in this way, the residence time in each reactor can be changed almost arbitrarily, and the above-mentioned lightening of the heavy components and hydrogenation of the solvent can be carried out in a series. The reaction can be carried out using a reactor.

As a specific embodiment, reactors such as a fixed bed, a fluidized bed, and a suspended bed may be connected in series, and oil (solvent component) may be supplied from a connection in the middle of the reactors. One example is a method in which a fixed bed reactor is alternately filled with catalyst layers and layers of inert fillers, and oil is supplied from the intermediate catalyst layers.

Furthermore, the method of supplying the oil is not limited to the method in which all the oil is supplied from the middle, and a part of the oil may be supplied to the first reaction zone together with the heavy components.

The present invention will be specifically explained below with reference to Examples.

[Example 1] Coal-based heavy oil containing multiple polycyclic aromatics was treated with nickel.
Molybdenum catalyst (16φ extruded product, composition MoO31
9.8wt%, NiO3,4wt%, A/, 2O37
6.8 wt%] and the coal were held at 450° C. and 15 KFX7crt12G for 7 minutes to solubilize the coal.

Thereafter, by using a high-temperature centrifuge and distillation operation, a solubilized substance of coal with a solid content of -9jiO, 3 wt% and a boiling point of 450°C or higher (hereinafter abbreviated as SC) and a boiling point of 300-45
The solvent fraction in the 0°C range was collected and used as a raw material for the hydrogenation test. In the solvent fraction, 42.9 wt% of typical 3.4-ring polycyclic aromatics (hereinafter abbreviated as PA component), which appear as a prominent peak in temperature-programmed gas chromatography, were partially hydrogenated. 4.2 wt% of (dihydride and tetrahydride, hereinafter abbreviated as HPA component) was present.

Next, a mixture of 1,000 g of the above SC and 3,300 g of oil was supplied to a fixed bed reactor at a feed rate of 250,117/hr, and the mixture was heated at 380°C and 150 Kg/cm.
At the request of G, a water purple reaction was carried out.

The fixed bed reactor has an N011 reactor and a NO,2 reactor connected in series, each with a 250 mA
It is filled with a nickel-molybdenum catalyst (same as above).

The reaction products were separated by distillation and measured by gas chromatography in the same manner as for the raw materials.

The results of this example are shown in Table 1.

The change in F2O amount was 10,100 O on the feed side and 537 g on the product side, giving a very good result with a conversion rate of 46.3%.

However, despite the decrease in the amount of PA components, the HP
It can be seen that the amount of component A increased slightly (it is not suitable for producing high-quality solvents).

[Example 2] The same fixed bed reactor as in Example 1 was used, using the same SC1,000, 300 g of the solvent fraction as in Example 1 as the test raw material.

A mixture of 801.000+7 and 700g of solvent fraction
No. 1 reactor at a feed rate of 0 g/hr, and the remaining solvent fraction 2.60 g/hr was added to their reaction products.
0g to 260F! The mixture was mixed under pressure at a feed rate of 7/hr and fed to the No. 2 reactor.

250 ml of nickel-molybdenum-based catalyst W (same as Example 1) was added to each reactor No. 1, No. 2, and No. 2.
.

is filled, the reaction temperature is 380℃, the pressure is 150Kg
/cm”G.

The reaction product was analyzed in the same manner as in Example 1, and the results shown in Table 1 were obtained.

In this example, the processing speed of both the SC and the solvent fraction is increased compared to Example 1.

In addition, the amount of HPA component increases in response to the decrease in the amount of PA component, and a high quality solvent is produced.

Furthermore, the change in SC amount is also equivalent to Example j.

Table 1

Claims (1)

[Claims] In a coal liquefaction method consisting of a first stage reaction step in which coal and a solvent are mixed and heated to solubilize the coal, and a second stage reaction step in which at least a part of the product of the first stage reaction step is hydrotreated. The product of the first stage reaction process has a boiling point of 400 to 5[1[
Separate the oil component with a boiling point of 1'C or less and the heavy component with a boiling point higher than that, and configure the second stage reaction step with a plurality of reaction zones connected in series with substantially equal pressure, and the heavy component is separated. A two-stage coal liquefaction method, characterized in that the oil is supplied from the first of the plurality of reaction zones, and the oil is supplied from the middle of the plurality of reaction zones.