JPH06179870A - Char fusion prevention method - Google Patents

Abstract

(57) [Summary] [Purpose] In the rapid thermal decomposition of new coal, coal with fusible properties is used, and there is no need to separate it from the additive material for anti-fussion. Provided is a method for preventing fusion of char, which does not carry latent heat out of the system due to an additive substance for prevention and allows stable and continuous operation. [Structure] In the rapid thermal decomposition of coal, as a method of preventing the fusion of char to the inner wall of the rapid thermal decomposition reactor, coal powder having fusible properties and coal powder having no fusible properties Y ≧ 0.5X +
44 (where Y is the blending ratio (wt%) of coal powder having no fusible property to the total blending amount of coal powder having fusible property and coal powder having no fusible property, and X is fusible property) Which is the Roga index of coal powder having the formula (1). [Effect] After achieving the above object, the rapid pyrolysis operation can be carried out without the risk of char fusion problems.

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 preventing char fusion in rapid pyrolysis of coal. More specifically, the present invention relates to a char fusion preventing method that can effectively use coal powder having a fusion property in a novel rapid thermal decomposition of coal.

[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, a useful gas, liquid, or solid product can be obtained at a pressure of 10 atm or less as high as at a pressure of about 200 atm. A rapid coal pyrolysis method characterized by rapidly heating coal at 10 atm or less at 10 ³ ° C / min or more, as a large amount of useful gas, liquid and solid products can be obtained without I found it.

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 species of coal are considered to be difficult to melt, there are coals that cause char fusion and others that do not cause char fusion, depending on the coal species of the raw material coal, and there is a case where soft fusion properties are exhibited. For this reason, in the above-mentioned rapid coal pyrolysis method, when the coal species that have been conventionally used are used, the inner wall of the rapid pyrolysis reactor and the apparatus high temperature part (4
The biggest problem is the fusion of char to above 00 ° C.

As a means for solving such a problem, a method of adding non-fusing substance powder such as sand, silica powder, alumina powder or char powder to raw coal powder and blending it into the above rapid pyrolysis reactor Is proposed.

However, when an inorganic substance powder such as sand, silica powder, or alumina powder is added and blended, char fusion can be prevented, but it is necessary to separate the inorganic substance powder and the char produced from the raw coal powder. Become. Moreover, since substances other than the raw coal powder are charged into the rapid pyrolysis reactor, the amount of raw coal supplied is reduced, and the productivity is reduced. Furthermore, due to the latent heat loss due to the non-fusible substance powder, there is a problem such as increasing the energy consumption rate, and the method of adding and blending the non-fusible substance powder still has many problems to be solved. As a method for preventing the fusion of char to date, it has not been possible to be a preferable solution, and it is not necessary to add the non-fusing substance powder to the mixture to separate it from the anti-fusion substance. At present, there is no method for preventing char fusion, which has high productivity, does not carry out latent heat to the outside of the system by the fusion prevention additive substance, and can be stably operated continuously.

[0007] Under the rapid pyrolysis conditions at a temperature rising rate of 10 ³ ° C / min or more, coal which causes char fusion due to softening and melting property is also a normal coking condition of 3 to 3.
At a heating rate of 10 ° C./min, it does not exhibit softening and fusion properties like coal that does not cause fusion of char, so it is a method of determining softening and fusion properties developed as a conventional coking technique. It is impossible to measure with a Giessler plastometer, dilatometer, etc. of the JIS method at a heating rate of 3 ° C / min whether coal causes char fusion or not during rapid thermal decomposition (either Since the fluidity also becomes 0), it could not be an effective judgment method for distinguishing the presence or absence of char fusion in advance in rapid thermal decomposition of coal.

The inventors of the present invention prevent the fusion of char to the inner wall of the rapid pyrolysis reactor, efficiently produce useful products from coal, and utilize them rationally in such fusion determination technology. As a result of earnest research on the technology, focusing on the fact that the coal logger test method is close to the conditions for rapid pyrolysis, the relationship between the measured values of raw coal loggers and the fusion problems during rapid coal pyrolysis was examined. It was found that coal coal types with an index of 10 or less do not cause fusion problems, and as a result, in coal rapid pyrolysis, by using coal with a Roga index of 10 or less as a raw material, the rapid pyrolysis reactor The inventors have found a method for preventing char fusion, which is characterized by preventing fusion of char to the inner wall.

[0009] However, there are a limited number of coal brands that do not have a cohesive property with a Roga index of 10 or less, and it is not preferable to use only such coal as a raw material because it imposes a large restriction on the raw material coal. .

Therefore, in such a resource environment, coal which is rather fusible must be used.
To date, no method has been developed for preventing char fusion by using coal having fusibility in rapid pyrolysis.

[0011]

Therefore, in view of the present state of the art of rapid pyrolysis of coal which has been made by the present inventors, it is an object of the present invention to provide char for rapid pyrolysis of coal. A fusion preventing method is provided.

Further, an object of the present invention is to use coal having a fusible property in the rapid thermal decomposition of a novel coal, which does not need to be separated from the anti-fusing additive substance and has high productivity. It is intended to provide a method for preventing fusion of char which enables stable and continuous operation without carrying out latent heat from the system due to the anti-fusion substance.

[0013]

[Means for Solving the Problems] In order to achieve the above-mentioned objects, the present inventors have proposed a novel rapid coal pyrolysis,
As a result of diligent research on the technology for preventing char fusion while using fusible coal, as a result of paying attention to the coal characteristics that there are fusible coals and non-fusible coals, It was found that 100% coal can be used as a raw material while preventing char fusion by using coal that does not have coal as a non-fusing substance that is added and blended to prevent char fusion. The present invention has been completed based on this finding.

That is, the object of the present invention is (1) in rapid coal pyrolysis, as a method for preventing the coal from adhering char to the inner wall of the rapid pyrolysis reactor, coal powder having fusible properties has fusible properties. No coal powder Y ≧ 0.5X + 44 (where Y is the ratio of coal powder having no fusibility to the total amount of coal powder having fusibility and coal powder having no fusibility) And X is the Roga index of coal powder having fusible properties) is added and blended in a ratio satisfying the formula (4).

Another object of the present invention is also achieved by (2) the coal fusion prevention method as described in (1) above, wherein the coal is in the form of particles having a particle size of 500 μm or less.

Still another object of the present invention is (3) X
Can be achieved by the char fusion preventing method as described in (1) or (2) above, which satisfies X> 10.

Still another object of the present invention is (4)
The temperature rising rate in the rapid thermal decomposition process of coal is 10 ³ ° C /
It is also achieved by the char fusion preventing method according to any one of the above (1) to (3), which is at least min.

[0018]

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

First, in the method for preventing char fusion in the rapid thermal decomposition of coal according to the present invention, the Roga index is used as an effective determination method for distinguishing the presence or absence of char fusion in advance. As the coal which does not have the raw material coal, a coal type having a Loga index of usually 10 or less, preferably 5 or less is used. Therefore, as the coal having the fusible property, the raw material coal of the coal type having the Loga index of more than 10 is used. Therefore, the raw material coal used in the present invention is not particularly limited, and coal of all existing coal types can be used as either coal having no fusible property or coal having fusible property. You can Here, the logarithmic index is one in which standard anthracite is added to a sample, which is subjected to carbonization under constant conditions, a drum test is performed on the resulting crucible coke, and its mechanical strength is expressed as an index. JIS M 880110. The value calculated according to the mathematical formula described in the calculation of 10.6 in the logger test method.

Further, in the method for preventing char fusion in the rapid pyrolysis of coal according to the present invention, since coal is operated with 100% coal, coal powder having fusibility is fused with coal powder having no fusibility. As additive powder for prevention, Y ≧ 0.5X + 44
The composition is added and blended at a ratio satisfying the formula. Here, Y is a blending ratio (% by weight) as coal powder having no fusible property (additive substance powder for anti-fusing property) with respect to the total blending amount of coal powder having fusible property and coal powder having no fusible property. And X is the Loga index of coal powder having fusibility, and X> 10. If the above formula Y ≧ 0.5X + 44 is not satisfied, the effect of preventing char fusion is not sufficient, which is not preferable.

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

As shown in FIG. 1, a rapid thermal decomposition apparatus 1 for coal according to the present invention includes a thermal decomposition reactor 2, and a coal hopper 4 is provided above a thermal decomposition reactor 2 via a feeder 3. Is installed. 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.

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

A pipe 28 for heat exchange is installed on the outer peripheral portion 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.

In order to obtain useful gas, liquid, and solid products by rapidly pyrolyzing coal using the coal rapid thermal decomposition apparatus 1 having the above-mentioned structure, based on the char fusion prevention method of the present invention. First, in the coal hopper 4, as described above, the coal having the fusible property is set to Y ≧ 0.5X +.
Each coal is charged at a rate satisfying the formula (44).
Incidentally, the coal is crushed in advance to a certain particle size or less,
Use a powder. The powdery coal particles,
Drop into the pyrolysis reactor 2 through the feeder 3.
Note that the feeder 3 and the coal hopper 4 are blown with a constant amount of coal gas from the pipe 35 in accordance with the content of the required product, so that the coal particle drop charging speed into the pyrolysis reactor 2 is increased. It can also be used for adjustment.

Subsequently, the coal particles dropped into the pyrolysis reactor 2 which has been heated by the heater 12 to a predetermined temperature in advance are discharged 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. At this time, by using the mixed coal powder satisfying the above formula, when the mixed coal powder falls in the rapid thermal decomposition reactor 2, the cohesive force of the fusible char is weakened, and then the rapid thermal decomposition is performed. Even if it is fused to the inner wall of the reactor, it drops during the operation, so that the fusible char does not block the rapid thermal decomposition reactor.

Thereafter, the pyrolyzed coal product is cooled to about 300 to 700 ° C. by heat exchange with the coal gas in the pipe 28 while passing through the pipe 16, and the coal product is cooled in the char vessel 15 as described above. The solid components in the coal product (mainly char) are collected and then sent to the cyclone 17 to completely remove the solid components in the coal product partially remaining in the gasification component as the product of coal. Collect at 18.

Subsequently, the gasified component from which the solid component has been removed is cooled to about 10 to 100 ° C. by the 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 remaining coal product, is sent to a gas analyzer (not shown) via 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 supplied by the feeder 3 is usually 500 μm or less, preferably 100 μm or less.

Further, 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, carbon monoxide or the like is used as the reducing gas, and benzene and toluene produced by continuous operation of the rapid thermal decomposition apparatus 1 are used. , Xylene (BTX)
And coal gas components such as hydrocarbon gas (HCG) may be circulated for reuse. In addition, the gas is usually heated to 500 to 1100 ° C, preferably 700 by the gas preheating tube.
It is used by preheating to ~ 900 ° C.

Further, as the rapid thermal decomposition conditions used in the char fusion preventing method according to the present invention, the thermal decomposition reactor 2 is used.
When the coal particles having the above-mentioned Roga index fall inside, the reactor internal pressure is usually 10 atm or less, preferably atmospheric pressure to 5 atm, and the temperature raising rate of the 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. Under the above-mentioned conditions, the above Y ≧ 0.5X + 44 (where Y is the blending ratio of coal powder having no fusibility to the total amount of coal powder having fusible properties and coal powder having no fusible properties ( %), And X is the Roga index of coal powder having fusibility.) Use a mixed coal powder of fusible coal powder and non-fusible coal powder satisfying the formula Since, in the mixed coal powder, almost both coal powders are uniformly dispersed, when falling in the rapid pyrolysis reactor 2, the char generated from the coal powder having a fusion property is Since the coal that is generated in the vicinity of coal powder that does not have fusible properties is relatively easy to contact with chars and preferentially adheres, the cohesive force of the fusible chars weakens, and rapid heat Even if it adheres to the inner wall of the cracking reactor, it then comes into contact with other coal particles during operation. As a result, the fusible char does not clog the rapid pyrolysis reactor, and extremely stable continuous operation is possible. Stable and useful gas, liquid, and solid products are obtained in large quantities. Is something that can be done. In addition,
Here, the temperature rising rate of the coal particles in the rapid thermal decomposition of coal is calculated by the following temperature rising rate calculation formula.

[0034]

[Equation 1]

In the above formula for calculating the rate of temperature rise, it is defined 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.

[0036]

EXAMPLES Examples of the present invention will be described below.

Example 1 Based on the char fusion prevention method according to the present invention, rapid coal pyrolysis was performed using the coal rapid pyrolysis apparatus 1 shown in FIG.

In the first embodiment, first, the raw material coal is first used in the coal hopper 4 in advance with a particle size of 74 μm or less and 100% or less.
1 coal of fusible coal having the Loga index shown in Table 1 (Coal A) and 3 brands of non-fusible coal (Coal B to Coal D) crushed into And coal B,
Table 2 shows the blending ratio of coal A with respect to the total blending amount of C or D.
40% to 70% as shown in Fig. 1, and after charging each mixed coal at a supply rate of 5 kg / hr, the powdery coal particles were dropped into the pyrolysis reactor 2 through the feeder 3. .

[0039]

[Table 1]

Then, the maximum temperature of the atmospheric gas is 900 ° C.
The coal particles dropped into the pyrolysis reactor 2 heated so that
The coal gas produced by the thermal decomposition reaction preheated to about ℃ is circulated at 40 liters / min (using nitrogen gas until coal gas is produced), and the atmospheric pressure is increased under a reducing (inert) atmosphere. Temperature rate of 10 ⁴ ° C / mi
n and a residence time of 2 sec, pyrolysis treatment was performed for each coal type for 5 hours, and it was confirmed whether char was fused to the inner wall of the rapid pyrolysis reactor. Of the results obtained,
Fig. 2 shows the relationship between the possibility of continuous operation in rapid coal pyrolysis, the Roga index of fusible coal, and the blending ratio (wt%) of non-fusible coal. The propriety is shown in Table 2.

[0041]

[Table 2]

From FIG. 2 above, in the rapid thermal decomposition of coal, in order to prevent the fusion of char to the inner wall of the rapid thermal decomposition reactor, coal powder having fusible properties and coal powder having no fusible properties are used. Was confirmed to be achievable by adding and blending at a ratio satisfying the formula of Y ≧ 0.5X + 44 (where Y
Is a blending ratio (% by weight) of coal powder having no fusible property to the total blending amount of coal powder having fusible property and coal powder having no fusible property, and X of coal powder having fusible property. Loga index).

[0043]

EFFECTS OF THE INVENTION The char fusion prevention method according to the present invention enables rapid pyrolysis operation without risk of char fusion trouble. Furthermore, it is not necessary to separate the char produced by rapid thermal decomposition of coal from the additive material for preventing fusion,
There is no carry-out of latent heat by the anti-fusing additive substance except that the productivity is not reduced due to the anti-fusing due to the operation with 0% coal.

[Brief description of drawings]

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

FIG. 2 shows the relationship between the possibility of continuous operation in rapid pyrolysis of coal, the Roga index of fusible coal, and the blending ratio (% by weight) of non-fusible coal in Examples of the present invention. It is a graph.

[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 (4)

[Claims] 1. As a method for preventing the fusion of char to the inner wall of a rapid pyrolysis reactor in the rapid pyrolysis of coal, coal powder having fusible properties and coal powder having no fusible properties of Y ≧ 0. 5
X + 44 (where Y is the blending ratio (% by weight) of coal powder having no fusible property to the total blending amount of coal powder having fusible property and coal powder having no fusible property, and X is the fusible property) Which is the Roga index of coal powder having the formula (1). 2. The method for preventing char fusion according to claim 1, wherein the coal is in the form of particles having a particle size of 500 μm or less. 3. The char fusion preventing method according to claim 1, wherein the X satisfies X> 10. 4. The method for preventing char fusion according to any one of claims 1 to 3, wherein the rate of temperature rise in the rapid thermal decomposition step of coal is 10 ³ ° C / min or more.