JPH06184549A - Rapid thermal cracking of coal - Google Patents

Abstract

PURPOSE:To prevent the stoppage due to the deposition of caking coal on the inside wall of a reactor and the high-temperature part of the equipment by feeding coal together with a noncaking substance in the rapid thermal cracking of coal. CONSTITUTION:Feed coal and an inert substance (e.g. char obtained by rapid thermal cracking) are added to a coal hopper 4 to form a mixture of Roga index in the range of 0-10. This mixture is ground to a grain size of 500mum or below, and fed to a thermal cracking reactor 2 through a feeder 3. The falling rate of the product is adjusted by blowing a coal gas from a pipe 35. The coal particles heated with a heater 12 are mixed with an atmospheric gas preheated to 500-1100 deg.C with a gas preheater 6 and fall through the reactor in an inert atmosphere under a pressure of 10atm or below at a temperature rise rate of 10<3> deg.C/min or above for a residence time of 0.5-10sec. The product is cooled to 300-700 deg.C by heat exchange during the passage through a pipe 16, and the solid component is collected in char vessels 15 and 18 and cooled to 10-100 deg.C with a cooling pipe 23, while the tar component is collected in tar pots 19a to 19c.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel method for rapid pyrolysis of coal. More specifically, in the rapid thermal decomposition of coal, a rapid thermal decomposition method of coal capable of preventing troubles such as adhesion to the inside of the rapid thermal decomposition apparatus and clogging inside the apparatus due to the caking property of coal. Regarding

[0002]

2. Description of the Related Art Conventionally, there have been technologies for producing coke from coal, and technologies for liquefying and gasifying coal whose main products are liquids and gases. For example, Hygas (Instit
ute of Gas Technology), gasification in a fluidized bed at 1010 ° C. and about 70 atm, and coal combined cycle power generation at NEDO in Japan perform gasification at 1300 to 1600 ° C. and 20 to 30 atm. Originally, when coal is heat-treated, solid (coke, char), liquid and gas are generated. With the exception of coke, coal liquefaction and gasification techniques are carried out at high temperatures and pressures.

The inventors of the present invention have diligently studied a technique for efficiently producing and rationally utilizing a useful product from coal in the above heat treatment technique, and as a result, 10 ³
It was found that by heating rapidly at ℃ / min or more, even under 10 atm, useful gas, liquid, and solid products as high as under 200 atm can be obtained. The present invention has found a rapid coal pyrolysis method characterized by rapidly heating coal at a pressure rise rate of 10 ³ ° C / min or more at 10 atm or less.

However, in the above-mentioned rapid thermal decomposition method for coal, the coal is rapidly heated at a temperature rising rate of 10 ³ ° C / min or more, so that the conventional coal heat treatment carried out at a relatively low speed under high temperature and high pressure. According to the method, even if the coal type of coal is considered to be difficult to melt, it may show a caking property depending on the coal type of the raw material coal. Therefore, in the above rapid coal pyrolysis method, even when using such conventionally used coal species, the inner wall of the rapid pyrolysis reactor and the apparatus high temperature part (400 ° C. or higher) are caking. The biggest problem is blockage caused by coal adhesion.

Further, even coal that causes caking under the rapid pyrolysis conditions with a temperature rising rate of 10 ³ ° C./min or more is 3 to 10 ° C./mi which is a normal coking condition.
At a heating rate of n, it does not show caking like coal that does not cause caking. For this reason, the softening / melting property determination method developed as a conventional coking technique is 3 ° C /
It is impossible to measure whether the coal is a coal that causes caking or a coal that does not cause it when rapidly pyrolyzed with a JIS method Giesler plastometer, dilatometer, etc. with a temperature rising rate of min (fluidity 0 Therefore, it cannot be an effective judgment method for identifying the presence or absence of caking property of coal in advance in the rapid pyrolysis of coal, and the presence or absence of the caking property of coal in such rapid pyrolysis of coal can be distinguished. To date, no effective judgment method has been found yet.

On the other hand, JP-A-55-23174 discloses a method for cooling a gaseous product obtained by catalytically gasifying, pyrolyzing or gasifying hydrocarbons without coking. The lower the bottom of the cooler into which the gaseous products are fed from the bottom, the smaller the cross-sectional area, and the particles filled with water gasification reaction are filled in this part to form a fixed bed. In order to remove the coke to be produced, the particles having a smaller particle size than that of the above are filled to form a fluidized bed, and at the same time, the particles having a smaller particle diameter are dropped in a fluidized state into the gap of the fixed bed. A method of cooling gasification products of hydrocarbons is disclosed.

In this method, the cross-sectional area is made smaller toward the bottom of the cooler into which the gas product is fed from the lowermost part, and particles having a large particle size active in the water gasification reaction are fixed bed in this part. By filling the upper part with a small particle size in a fluidized state and dropping a part of the small particle size into the fixed bed upper layer to form coke adhering to the surface of the large particle due to the small particle size. It is removed by collision, peeling action, and water gasification reaction with steam.
Sand, zircon sand, or the like is used for the particles having a small particle size.

However, in the above cooling method, as a means for forcibly removing coke once generated by physical action after generation, a fluidized bed is formed by particles having a small particle size, and the fluidized bed is formed into particles having a small particle size. While the gravitational force of downward gravity and the buoyancy of the gas flow from the bottom to the top are used to flow in the container and cause frequent collisions between particles, the coke adhering to the particle surface is separated and removed. ,
In the thermal decomposition method of coal, coal is rapidly pyrolyzed within a very short period (usually 0.5 to 10 seconds) of charging and dropping into the thermal decomposition reactor. When using particles with a small particle size, etc., the pressure due to the gravity and the gas flow applied to it is downward,
As described above, it is very difficult to make particles flow repeatedly and to repeatedly collide, which complicates the apparatus, and there are many problems that must be solved.In addition, the inner wall of the reactor and the high temperature part of the apparatus are not cohesive. If the tinged coal is once attached and then is to be peeled off, if it is not done by colliding only the particles or the like with the caking coal and imparting sufficient energy for peeling, it will be attached instead. Further, the coal, the particles, and the like adhere to the caking coal that is present, which in turn causes blockage, which is not preferable. Therefore, in order to selectively cause only the particles or the like to collide with each other, a magnetic particle or the like is used, and a magnetic field is intermittently formed from the outside by using an electromagnet or the like to form the magnetic particle on the inner wall of the reactor or the high temperature part of the apparatus. Etc. can collide with each other, but it requires extremely large-scale equipment including an electromagnet and the like, and there is a problem in that the cost of magnetic particles and the like becomes high economically.

Therefore, to date, an effective means has been found that can easily prevent clogging due to the adhesion of the caking coal to the inner wall of the rapid coal pyrolysis reactor and the high temperature part of the apparatus. Not not.

[0010]

Accordingly, it is an object of the present invention to provide a new method for rapid pyrolysis of coal.

Another object of the present invention is to prevent coal clogging caused by adhesion of caking coal to the inner wall of the rapid pyrolysis reactor and the high temperature part of the apparatus during rapid pyrolysis of coal. A thermal decomposition method is provided.

Further, an object of the present invention is to prevent the adhesion of coal to the inner wall of the rapid pyrolysis reactor by judging the caking property of the raw material in advance and using the raw material which does not cause the caking property. It provides a rapid thermal decomposition method for coal.

[0013]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have earnestly studied a novel rapid coal pyrolysis method for preventing the caking property of coal, and as a result, have a caking property as a raw material. When the raw material is rapidly pyrolyzed by supplying a substance (hereinafter, also simply referred to as an inactive substance) together with coal in a specific mixing ratio, the inner wall of the rapid pyrolysis reactor is preferably used. And it was found that it is possible to prevent clogging due to the adhesion of caking coal to the high temperature part of the equipment, and an effective judgment to distinguish the presence or absence of caking property of coal in advance in the rapid thermal decomposition of coal. As a method, focusing on the fact that the logger test method for coal is close to the conditions for rapid pyrolysis, the measured values of loggers for raw materials (mixtures of non-caking substances and coal) and blockage troubles during rapid pyrolysis of coal As a result of examining the relationship between The raw material in the range of index 0 onsets saw that does not cause clogging problems, in which the present invention has been completed based on these findings.

That is, the object of the present invention is achieved by (1) a rapid thermal decomposition of coal, which is characterized in that a substance having no caking property is supplied together with the coal.

Another object of the present invention is (2) the Roga index of the mixture of coal and the substance having no caking property is 0 to 0.
It can also be achieved by the rapid coal pyrolysis method described in (1) above, wherein the mixing ratio of the coal and the substance having no caking property is adjusted so as to be 10.

Still another object of the present invention is also achieved by (3) the rapid pyrolysis method for coal shown in the above (1) or (2), wherein the Loga index is 0 to 5.

Still another object of the present invention is (4)
It is also achieved by the rapid coal pyrolysis method described in any one of (1) to (3) above, wherein the coal is in the form of particles having a particle size of 500 μm or less.

Another object of the present invention is: (5) The temperature rising rate in the rapid thermal decomposition step of coal is 10 ³ ° C / min.
It is also achieved by the rapid coal pyrolysis method described in any one of the above (1) to (4).

[0019]

The present invention will be described in more detail based on the embodiments.

First, in the rapid coal pyrolysis method according to the present invention, the Roga index is used as an effective determination method for distinguishing the presence or absence of caking properties of coal used as a raw material. In order to prevent adhesion of the raw material coal to the inner wall of the thermal decomposition reactor due to the caking property of the raw material coal, the Loga index of the raw material (a mixture of a substance having no caking property and coal) is usually 0 to 10. It is necessary to use the raw material coal of coal type which is preferably 0 to 5. When the Loga index exceeds 10, it is not preferable because a clogging trouble or the like due to the caking property of coal occurs. Here, the Loga index is a value obtained by adding standard anthracite to a sample (raw material), carbonizing under constant conditions, performing a drum test on the resulting crucible coke, and expressing its mechanical strength as an index. For details, JIS
M 8801 10. The value calculated according to the mathematical formula described in the calculation of 10.6 in the logger test method.

Next, as raw material coal, the raw material (a mixture of a substance having no caking property and coal) has a Roga index of 0 to 10.
When the raw coal has a Roga index of more than 10, since the Roga index of a substance having no caking property is almost 0, the addition of the substance having no caking property Since the Roga index of the entire raw material can be arbitrarily adjusted by the above method, it is not particularly limited, and for example, any of anthracite, semi-anthracite, bituminous coal, subbituminous coal, lignite, etc., or a mixed coal thereof can be used.

The non-caking substance used as a part of the raw material of the present invention may be any substance that does not have a caking property under the rapid thermal decomposition conditions described later, and examples thereof include sand and silica. Powder, alumina powder, zircon sand, ceramics or coal or rapid pyrolysis char of coal can be used, but preferably, it is not necessary to separate it from the product char in the subsequent step, and it is recycled by recycling to use latent heat. The char is a rapid pyrolysis char of coal with less reduction of gas and useful gas generation.

In the above raw material, by adding a substance having no caking property to coal, almost both of the raw material mixture are uniformly dispersed. Therefore, when dropping in the rapid pyrolysis reactor 2, Coal particles having a caking property, by contacting and adhering with a substance having no caking property in the vicinity of the coal particles, the caking force of the coal particles is weakened, and then rapid thermal decomposition. Even if it contacts the inner wall of the reactor, it hardly adheres, and even if it adheres, it easily separates from the wall due to collision with other non-caking substances that have fallen later. Since it will fall, clogging due to adhesion to the inner wall of the thermal decomposition reactor due to the caking property of the coal particles does not occur, extremely stable continuous operation becomes possible, stable and useful gas, liquid, solid That the product can be obtained .

Therefore, as the average particle size of the substance having no caking property, it is preferable that the substance can be conveyed by air flow during thermal decomposition and can be uniformly dispersed with the coal particles used.
The average particle size of the coal particles used is 0.1 to 5 times, preferably 0.5 to 3 times, and more preferably 0.8 to 2 times.

Next, FIG. 1 is a state of use diagrammatically showing the construction of an embodiment of a rapid coal pyrolysis apparatus used in the rapid coal pyrolysis method according to the present invention.

As shown in FIG. 1, the coal rapid thermal decomposition apparatus 1 according to the present invention includes a thermal decomposition reactor 2, and a coal hopper 4 is provided above the thermal decomposition reactor 2 via a feeder 3. is set up. A gas supply port 5 is provided on the upper side surface of the thermal decomposition reactor 2, and the gas supply port 5 and the gas exhaust port 7 of the gas preheating pipe 6 are connected by a pipe 8. The gas supply port 9 of the gas preheating pipe 6 is connected to the gas cylinder 10 by a pipe 11. Further, a reactor heater 12 and a preheater tube heater 13 are installed as heaters around the entire periphery of the side surfaces of the thermal decomposition reactor 2 and the gas preheater tube 6 at regular intervals.

A product outlet 14 such as a liquid produced by the thermal decomposition of coal is provided in the lower part of the thermal decomposition reactor 2, and the product outlet 14 and the char vessel 15 are connected by a pipe 16. It is connected. Similarly, the char vessel 15
Char vessel 18 with cyclone 17, first
The gas analyzer (not shown) through the tar pot 19a, the second tar pot 19b, the third tar pot 19c, the tar filter 20 and the gas meter 21 through the pipes 22, 23, 24, 25, 26 and 27, respectively. It is connected.

A pipe 28 for heat exchange is installed on the outer periphery of the pipe 16, and one end of the pipe 28 is connected to the path of the pipe 11 by a 3-port switching valve 29. A blower 30 is provided on the path, and the other end of the pipe 28 is connected to the pipe 27 by a 3-port switching valve 31. Further, a water cooling type cooling pipe 32 is arranged on the outer peripheral portion of the pipe 23.

The pipe 33 branched from the pipe 28 from the blower 30 to the 3-port switching valve 31 is connected to the pipe 27 between the gas meter 21 and the 3-port switching valve 31, and the route of the pipe 33. An opening / closing valve 34 is provided above. A pipe 35 branched from the blower port side pipe 28 of the blower 30 is connected to the feeder 3 and the coal hopper 4.

Using the coal rapid thermal decomposition apparatus 1 having the above-mentioned structure, the coal is rapidly pyrolyzed and the thermal decomposition reactor 2 is used.
In order to obtain a useful gas, liquid, or solid product that can be continuously operated without causing blockage due to the caking property of the coal on the inner wall of the coal, first of all, in the coal hopper 4, raw coal and an inert substance are mixed. The raw material coal and the inert material are charged so that the logarithmic index of the mixture may be in the range of 0 to 10, and the mixed material is then fed from the coal hopper 4 to the mixture. The coal particles in powder form which have been supplied and crushed to a certain size or less and an inert substance are dropped into the pyrolysis reactor 2 through the feeder 3. It should be noted that the feeder 3 and the coal hopper 4 are blown with a fixed amount of coal gas from the pipe 35 in accordance with the content of the required product, whereby the coal is agitated to facilitate the crushing and the thermal decomposition reaction. Bowl 2
It can also be used for adjusting the dropping and charging speed of the coal particles into the coal.

Subsequently, the coal particles dropped and loaded into the pyrolysis reactor 2 which has been heated by the heater 12 to a predetermined temperature are approximately charged by the gas preheating pipe 6 supplied from the gas supply port 5. Mixing with atmospheric gas preheated to about 500 to 1100 ° C., in an inert or reducing atmosphere, at a heating rate of 10 ³ ° C./min or more at 10 atm or less, and a residence time within a range of 0.5 to 10 seconds The thermal decomposition treatment is performed by dropping the inside of the thermal decomposition reactor 2.

Then, when passing through the pipe 16, the pipe 28
The product of coal pyrolyzed by heat exchange with the coal gas is cooled to about 300 to 700 ° C., and solid components (mainly char) and inert substances in the coal product are cooled in the char vessel 15. The solid component in the coal product, which was collected and then sent to the cyclone 17 and partially remaining in the gasification component as a product of coal, was completely charged in the char vessel 1.
Collect at 8. The rapid pyrolysis char collected in the char vessels 15 and 18 can be recycled as an inert substance by supplying it to the coal hopper 4 through a pipe (not shown). Further, inactive substances other than the rapid pyrolytic char can be separated into the rapid pyrolytic char and the inactive substance by a separation device (not shown) outside the system, and then the inactive substance can also be recycled. it can.

Subsequently, the gasified component from which the solid component has been removed is cooled to about 10 to 100 ° C. by a water-cooling type cooling pipe 32 when passing through the pipe 23 and sent to the tar pot 19a, where the gasified component is supplied. Part of tar component (liquid product)
As a tar pot 19b, 1
After being condensed in 9c to almost completely collect the tar component, the tar filter 20 completely collects the tar component.

Thereafter, the low-temperature gasification component, which is the rest of the coal product, is sent to a gas analyzer (not shown) through a gas meter 21 and benzene, toluene, xylene (BT).
X) and hydrocarbon gas (HCG), or
Alternatively, the low-temperature gasification component can be adjusted by adjusting the 3-port switching valve 31 so as to pass through the gas preheating pipe 6 and the thermal decomposition reactor 2
It can be used as a coal gas for rapid thermal decomposition reaction of coal.

The particle size of the coal particles crushed by the coal hopper 4 is usually 500 μm or less, preferably 100 μm or less.

As the gas preheated by the gas preheating pipe 6, an inert or reducing gas can be used. Nitrogen gas or the like is used as the inert gas, and hydrogen or the like is used as the reducing gas, but benzene, toluene, xylene (BTX) produced by continuous operation of the rapid thermal decomposition apparatus 1 is used. ) And coal gas components such as hydrocarbon gas (HCG) may be circulated for reuse. The gas is preheated to 500 to 1100 ° C, preferably 700 to 900 ° C by the gas preheating tube.

Further, the conditions for rapid pyrolysis in the rapid coal pyrolysis method according to the present invention include, when the mixture of coal particles having the above-mentioned Roga index falls in the pyrolysis reactor 2, the reactor The internal pressure is usually 10 atm or less, preferably atmospheric pressure to 5 atm, and the temperature raising rate of coal particles is usually 10 ³ ° C / min.
Or more, preferably 10 ³ to 10 ⁷ ° C / min, more preferably 10 ³ to 10 ⁴ ° C / min, and the maximum temperature of the atmosphere gas in the reactor 2 (corresponding to the final temperature of coal particles) is usually 700 to 1100 ° C, preferably 700
˜900 ° C., and the residence time of the coal particles in the reactor 2 is usually 0.5 to 10 seconds, preferably 1 to 5 seconds, more preferably 2 to 3 seconds. By rapidly pyrolyzing coal particles in a mixture with a Roga index of 0 to 10 under the above conditions, continuous operation can be performed without causing clogging trouble, and stable and useful gas, liquid, and solid products can be obtained. Is what you can get. The temperature rising rate of the coal particles in the rapid thermal decomposition of coal is calculated by the temperature rising rate calculation formula shown below.

[0038]

[Equation 1]

In the above equation for calculating the rate of temperature increase, it is assumed that there is no partial temperature change of the particles and there is no change in the physical properties such as density and specific heat due to the thermal decomposition reaction.

[0040]

EXAMPLES Examples of the present invention will be described below.

Example 1 Using the coal rapid thermal decomposition apparatus 1 shown in FIG. 1, rapid thermal decomposition of coal according to the present invention was performed.

In the first embodiment, first, as the sample raw materials (12 kinds of A1 to F1 and A2 to F2) having the Loga index shown in Table 1 in the coal hopper 4, as raw material coal (2 kinds), as inactive substances, respectively. Table 1 also shows the rapid pyrolysis char of
After charging the mixture mixed at the ratio shown in the above with a supply rate of 5 kg / hr, the mixture was crushed by the coal hopper 4 and crushed to a particle size of 74 μm or less (100%) and powdery coal particles and The rapid pyrolysis char was dropped into the pyrolysis reactor 2 through the feeder 3. Subsequently, the mixture particles dropped into the pyrolysis reactor 2 heated so that the maximum temperature of the atmospheric gas reaches 900 ° C. were preheated to about 900 ° C. from the gas supply port 5. Under a reducing (inert) atmosphere by circulating the coal gas produced by the thermal decomposition reaction at 40 liters / min (using nitrogen gas until the coal gas is produced),
Temperature rise rate is 10 ³ ° C / min, residence time is 2 s as normal pressure
As ec, the thermal decomposition treatment was performed for each sample raw material for 5 hours, and it was confirmed whether or not there was a clogging trouble due to the caking property of coal to the inner wall of the rapid thermal decomposition reactor 2. The results obtained are shown in Table 1.

[0043]

[Table 1]

[0044]

EFFECT OF THE INVENTION By the method for rapid pyrolysis of coal according to the present invention, by using a mixture of coal and an inert substance having a Loga index of 0 to 10, preferably 0 to 5, the cohesiveness of coal is improved. The rapid pyrolysis operation can be carried out without the risk of clogging trouble.

Further, the supply ratio of the coal and the inert substance which can operate without clogging trouble can be easily selected by the measurement of the Loga index, and the measurement of the Loga index itself is simple and effective in terms of workability. It is a judgment method.

[Brief description of drawings]

FIG. 1 is a use state diagram schematically showing a configuration of an embodiment of a coal rapid pyrolysis apparatus that can be used in a coal rapid pyrolysis method according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Coal rapid thermal decomposition apparatus 2 ... Thermal decomposition reactor 3 ... Feeder 4 ... Coal hopper 5, 9 ... Gas supply port 6 ... Gas preheating pipe 7 ... Gas exhaust port 10 ... Gas cylinder 8, 11, 16, 22-28, 33, 35 ... Piping 12 ... Reactor heater 13 ... Preheating tube heater 14 ... Product take-out port 15, 18 ... Chervessel 17 ... Cyclone 19a, 19b, 1
9c ... Tar pot 20 ... Tar filter 21 ... Gas meter 29, 31 ... 3 port switching valve 30 ... Blower 32 ... Water cooling type cooling pipe 34 ... Open / close valve

Claims (5)

[Claims] 1. A rapid thermal decomposition method for coal, characterized in that in the rapid thermal decomposition of coal, a substance having no caking property is supplied together with the coal. 2. The mixing ratio of the coal and the non-caking substance is adjusted so that the Loga index of the mixture of the coal and the non-caking substance is 0-10. The rapid pyrolysis method for coal according to claim 1, which is characterized in that. 3. The rapid coal pyrolysis method according to claim 1, wherein the Loga index is 0 to 5. 4. The rapid coal pyrolysis method according to claim 1, wherein the coal is in the form of particles having a particle size of 500 μm or less. 5. The rapid pyrolysis method for coal according to claim 1, wherein the rate of temperature rise in the rapid pyrolysis step for coal is 10 ³ ° C./min or more.