JP2651532B2 - Pyrolysis method of coal - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for pyrolyzing coal.

Conventional technology and its problems High-calorie gas, benzene,
As a method of producing liquid products such as toluene and xylene, finely pulverized coal is mixed with high-temperature and high-pressure hydrogen gas, the temperature is rapidly increased, and the coal is rapidly pyrolyzed in a reaction time of several seconds to several tens of seconds. Methods are known. It has been found that the yield of liquid products in such rapid pyrolysis of coal greatly depends on the hydrogen content at the time of the generation of pyrolysis fragments. At the time of thermal decomposition of coal, it is necessary to supply hydrogen with good timing.

However, in the above-mentioned rapid thermal decomposition method of coal according to the prior art, the thermal decomposition of coal is simply performed in a hydrogen gas or a mixed gas atmosphere of hydrogen gas and methane, and such a method is substantially performed. It can be said that this is a hydropyrolysis method in which hydrogen is supplied from the gas phase in the form of hydrogen molecules. In the hydropyrolysis method, since the dissociation energy of hydrogen molecules into hydrogen atoms is large, the addition of hydrogen atoms to pyrolysis fragments depends on the hydrogen acceptor ability of coal. Therefore, hydrogen does not transfer efficiently to coal, and the yield of liquid product is limited.

Means for Solving the Problems The present inventor has conducted various studies in view of the current state of the art as described above, and as a result, when coal powder is pretreated with a hydrogen-donating solvent to swell, The physical effect that the tar radicals are easily trapped by the char radicals and are easily scattered out of the particles due to the expansion of the pore diameter of the coal, and efficient hydrogen transfer from the solvent through chemical interaction with coal It has been found that the chemical effect of stabilizing tar radicals significantly improves the yield of liquid products.

That is, the present invention provides the following method: "After a mixture of coal powder and a hydrogen-donating solvent is heated and swelled at 150 to 300 ° C in an inert gas atmosphere, an inert gas or hydrogen is used. 5 at a heating rate of 500 ° C / sec or more in a gas atmosphere
A method for pyrolyzing coal, wherein the method is heated to and maintained at 00 to 900 ° C. There is no restriction on the type of coal, the place of production, and the like for the coal that is the subject of the present invention. Coal has a particle size of 100 to increase reactivity.
It is preferable to use the powder in the form of a powder having a mesh size or less.

Examples of the hydrogen-donating solvent include tetralin, tetrahydroquinoline, dihydroanthracene, tetrahydroanthracene, dihydrophenanthrene, tetrahydrophenanthrene, dihydropyrene, tetrahydropyrene, dihydrochrysene, tetrahydrochrysene, and the like.

The mixing ratio of the coal and the hydrogen-donating solvent is about 10 to 60 parts, more preferably about 30 to 40 parts, per 100 parts by weight of the former (hereinafter simply referred to as "parts"). If the amount of the hydrogen-donating solvent is too small, the pretreatment of the coal is not sufficiently performed, whereas if an excessive amount is used, there is no problem in the thermal decomposition reaction itself. The solvent itself is only thermally decomposed and does not contribute to the improvement of the yield of the liquid product.Moreover, excessive heat energy is wasted to raise the temperature to a predetermined reaction temperature, and the plant is enlarged. For reasons, not preferred.

In the present invention, as a pretreatment, a mixture of coal powder and a hydrogen-donating solvent is nitrogen gas, about 150 to 300 ° C. in an inert gas atmosphere such as helium gas, more preferably 200 to 300 ° C.
Heat at 250250 ° C. for about 15 minutes to 1 hour to swell. The pressure of the inert gas is not particularly limited, but is usually 0.
It is about 5 to 2.0 MPa. Since the pretreatment needs to be performed under conditions where the coal itself does not thermally decompose, the treatment temperature and time should be appropriately selected depending on the type of coal.

The coal powder, which has been pretreated as described above, may be used as it is or after cooling, to a temperature range of about 500 to 900 ° C (more preferably, to a temperature range of about 700 to 800 ° C).
At a heating rate of 0 ° C / sec or more (more preferably, 1000 ° C /
The temperature is raised at a rate of not less than seconds, the temperature is maintained for about 1 to 60 seconds (more preferably, for about 5 to 15 seconds), and after thermal decomposition, rapid cooling is performed. If the heating rate is too low, the effect cannot be expected because the stabilization time of the pyrolysis fragment and the hydrogen donation time of the hydrogen-donating solvent do not match. The pyrolysis temperature and time must be selected so that the decomposition reaction of the hydrogen-donating solvent used in the swelling pretreatment itself is accelerated and hydrogen is not consumed, so that the solvent itself does not decompose. There is. The thermal decomposition may be performed under normal pressure to a pressure of about 10 MPa. The rapid cooling after the thermal decomposition reaction is for suppressing the secondary reaction of the liquid product.

Effects of the Invention According to the present invention, the yield of a liquid product is remarkably improved during pyrolysis of coal.

Examples Examples and comparative examples are shown below to further clarify the features of the present invention.

Example 1 To 100 parts of Pacific charcoal powder pulverized to a mesh size of 200 mesh or less, 50 parts of tetralin was added, and the mixture was filled in an autoclave.
It was heated at 250 ° C. for 1 hour in a N ₂ gas atmosphere of Pa to swell.

Next, the coal powder that has been subjected to the swelling pretreatment is wrapped in a ferromagnetic iron foil, housed in a reaction tube, heated at a high frequency under a normal pressure He atmosphere, and rapidly heated to 764 ° C. at a heating rate of 500 ° C./sec. , And maintained at the same temperature for 10 seconds.

Then, the generated volatiles were introduced during the reaction at room temperature.
The mixture was quenched by He gas and the tar was collected on the wall of the reaction tube and on quartz wool filled in the reaction tube.

Comparative Example 1 The coal powder was rapidly heated under the same conditions as in Example 1 without performing the swelling treatment.

Example 2 Coal powder was swollen under the same conditions as in Example 1, then wrapped in a ferromagnetic iron foil, housed in a reaction tube, and heated at a high frequency of 600 ° C./sec under a 5 MPa H ₂ gas atmosphere. The mixture was rapidly heated to 746 ° C. at the speed and kept at the same temperature for 10 seconds.

Then, the generated volatiles were introduced into the reaction tube at room temperature.
The mixture was quenched by He gas and the tar was collected on the wall of the reaction tube and on quartz wool filled in the reaction tube.

Comparative Example 2 The coal powder was rapidly heated under the same conditions as in Example 2 without performing the swelling treatment.

Table 1 shows the yield (%) of tar, char, and product gas in each of the examples and comparative examples.

As is evident from the results shown in Table 1, when coal is pre-swelled with a hydrogen-donating solvent, the tar yield is reduced from about 23% to 32% as compared with the case without pre-swelling. It is increasing.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-212494 (JP, A) JP-A-57-190090 (JP, A) JP-A-50-39294 (JP, A) JP-A-49-49 188 (JP, A)

Claims (2)

(57) [Claims] 1. A mixture of coal powder and a hydrogen-donating solvent is heated and swelled at 150 to 300 ° C. in an inert gas atmosphere, and then heated to 500 ° C./sec or more in an inert gas or hydrogen gas atmosphere. A method for pyrolyzing coal, wherein the method is heated to a temperature of 500 to 900 ° C. at a speed and held. 2. A method for pyrolyzing coal according to claim 1, wherein high-frequency heating is performed in an inert gas or hydrogen gas atmosphere to 500 to 900 ° C. at a heating rate of 500 ° C./sec or more. .