JPH06184552A - Rapid thermal cracking of coal - Google Patents

Abstract

PURPOSE:To control the product without changing the type of coal by irradiating coal with a radiation at a specified dose and subjecting the irradiated coal to rapid thermal cracking. CONSTITUTION:Coal irradiated with a radiation at a does of 10<3>R or above is fed to a coal hopper 4 and ground to a particles of a grain size of 500mum or below. The particles are allowed to fall and fed to a thermal cracking reactor 2 through a feeder 3. A coal gas is sent from a pipe 35 to adjust the feed rate of coal particles. The coal particles are mixed with an atmospheric gas preheated with a preheater 6 and thermally cracked during fall through the reactor 2 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 maximum temperature of the atmospheric gas is 700-1100 deg.C. The solid component is collected in char vessels 15 and 18, and the tar component is collected in tar pots 19a to 19c, while the low-temperature gas component is recovered through a gas meter 21. According to this process, the yields of the desired gaseous, liquid and solid products can be increased without changing the type of the coal used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel coal rapid pyrolysis method. More specifically, the present invention relates to a rapid coal pyrolysis method capable of preliminarily treating coal to obtain a large amount of effective products in the rapid pyrolysis of coal.

[0002]

2. Description of the Related Art Currently, there are technologies for producing coke from coal, and technologies for liquefying and gasifying coal whose main products are liquid and gas. For example, Hygas (Institut
In e of Gas Technology), gasification in a fluidized bed at 1010 ° C. and about 70 atm is performed, and in coal combined cycle power generation at NEDO in Japan, gasification is performed at 1300 to 1600 ° C. at 20 to 30 atm. However, with the exception of coke, coal liquefaction and gasification technologies are both carried out under high temperature and high pressure.

Accordingly, the inventors of the present invention have earnestly studied a technique for efficiently producing a useful product from coal in the above-mentioned coal liquefaction and gasification techniques, and as a result, rapidly heat the coal at a specific heating rate. According to this finding, it is possible to obtain useful gas, liquid, and solid products at the same level as under the pressure of about 200 atm, which is conventionally required even under extremely low pressure, and based on this finding, liquefaction of coal under high pressure and As a technique capable of performing gasification, a rapid thermal decomposition method of coal was found by rapidly heating coal at a temperature rising rate of 10 ³ ° C / min or more at 10 atm or less.

By rapidly pyrolyzing coal by the above method, solids (mainly char), liquids and gases are produced, and these products can be effectively used according to their respective uses. .

However, in the above-mentioned rapid pyrolysis of coal, it is necessary to control each product mainly by changing the coal brand, and therefore the control range of the product is narrow and limited. In addition to that, by changing the lot, a storage must be installed for each coal brand, and in processing such as crushing, in order to ensure products with stable characteristics for each coal brand, for example, Each time the lot is changed, it is necessary to wash the crusher and the like to prevent the coal of the previous lot from mixing in, which causes a problem in terms of equipment and work.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to treat coal in advance in order to solve various problems in the novel rapid coal pyrolysis technology made by the present inventors. It is intended to provide a rapid coal pyrolysis method capable of controlling a product without changing a coal brand.

[0007]

In order to achieve the above-mentioned object, the inventors of the present invention treated the coal in advance,
As a result of diligent research on a rapid coal pyrolysis method capable of controlling products without changing the coal brand,
By irradiating coal with radiation, a chemical reaction occurs,
Focusing on the change in coal properties, various studies were conducted to apply radiation to the pretreatment technology of raw coal for rapid pyrolysis of coal.As a result, the chemical reaction differs depending on the atmosphere when the coal is exposed to radiation. It was discovered that the rapid thermal decomposition products obtained due to different properties also differ greatly.According to this finding, when irradiation is carried out in a reducing atmosphere, the carbon skeleton structure is a polycyclic structure rich in aromatic compounds. Is decomposed by radiation, and an active hydrogen atom is added to the decomposed coal molecule (for example, the one in which the polycyclic structure polymer bond is broken and decomposed into a monocyclic structure molecule). By doing so, the coal becomes a low molecular weight coal property, so that the yield of tar and gas can be increased by rapid thermal decomposition using the coal, and conversely, when irradiation is performed in an oxidizing atmosphere. Is above Radiation decomposes coal, which is a polymer with a ring structure, and the decomposed coal molecules and active oxygen atoms are crosslinked, resulting in polymerized coal properties. Pyrolysis can increase the yields of heavy tar and char, and the present invention has been completed based on these findings.

That is, the object of the present invention is achieved by (1) a rapid pyrolysis method for coal, which comprises irradiating coal with radiation of 10 ³ roentgen or more and then rapidly pyrolyzing the coal.

Another object of the present invention is (2) in the rapid thermal decomposition step of coal, wherein the coal is used at 10 atm or less for 10 times or less.
^It can also be achieved by the rapid coal pyrolysis method described in (1) above, in which heating is performed rapidly at a temperature rising rate of ³ ° C./min or more.

Another object of the present invention is (3) the rapid thermal decomposition of coal in the rapid thermal decomposition step of coal as described in (1) or (2) above, wherein the coal is in the form of particles having a particle size of 500 μm or less. It can also be achieved by a decomposition method.

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, in which the maximum temperature of the atmospheric gas in the rapid coal pyrolysis step is 700 to 1100 ° C.

[0012]

In the method for rapid thermal decomposition of coal of the present invention, the coal is preliminarily irradiated with radiation in an oxidizing or reducing atmosphere to cause a chemical reaction to arbitrarily change the coal property, and the coal having the changed coal property is subjected to a novel rapid reaction. By rapidly heating using a pyrolysis method, the yield of the desired product can be increased or changed as needed without changing the coal brand, and the rapid pyrolysis products can be freely controlled. Is something that can be done.

In such a rapid coal pyrolysis method according to the present invention, as a method for pretreating the coal before the rapid pyrolysis of the coal, the coal is treated with 10 ³ roentgen or more, preferably 10 ⁴ to 10 ⁶ roentgen. It is irradiated with radiation. If the radiation irradiation is less than 10 ³ roentgen, sufficient change in coal properties cannot be achieved, and even if rapid thermal decomposition is performed using the coal, the yield of the target product is increased. It cannot be done and is not preferable.

The atmosphere at the time of irradiation with the above-mentioned radiation is arbitrarily selected depending on the desired rapid thermal decomposition product, and when the yield of light tar and gas is increased as the rapid thermal decomposition product. Irradiate in a reducing atmosphere. By irradiating under the reducing atmosphere, the molecular weight of coal is lowered, so that the yield of light tar and gas can be increased in the case of rapid thermal decomposition using the coal. The reducing atmosphere gas is not particularly limited, and for example, hydrogen, ammonia, carbon monoxide gas or the like can be used. Further, when increasing the yields of heavy tar and char as the above products, irradiation is performed in an oxidizing atmosphere. By irradiating under the oxidizing atmosphere, the coal is polymerized and the yield of heavy tar and char can be increased when the coal is rapidly pyrolyzed. The oxidizing atmosphere gas is not particularly limited, and for example, an atmosphere of oxygen, air, oxygen-enriched air, or the like, preferably an economically inexpensive air atmosphere can be used.

Further, as the above-mentioned radiation, cobalt 6
Γ rays, β rays, electron beams or X rays obtained by using 0 etc. as a radiation source
It is possible to use relatively high energy radiation such as rays. Further, radioactive wastes generated by nuclear reactor operation and nuclear fuel reprocessing can be effectively used as a radiation source.

The apparatus for irradiating the coal with radiation is not particularly limited, and an existing radiation apparatus can be used. For example, a cylindrical β-ray provided in a water tank whose periphery is shielded by lead. For example, a radiation source such as cobalt 60 is loaded into a fixing device capable of transmitting only specific radiation, and an object to be irradiated is suspended from the upper portion of the water tank, and by adjusting this, the object to be irradiated is placed in the hollow cylindrical portion. An example of such a device is a device that can be taken in and out. The reason why the radiation source is placed in water is that water is preferable because it can be used as a cooling agent and a moderator. In addition, as a temperature condition for performing the radiation irradiation, it is usually desirable to use room temperature (normal temperature in the case of water) from the viewpoint of preventing the risk of melting the radiation source due to high temperature. Further, the pressure condition does not have to be specified in particular, and the pressure may be normal pressure.

The raw material coal used in the rapid coal pyrolysis method of the present invention is not particularly limited, and anthracite, semi-anthracite, bituminous coal, subbituminous coal, lignite and the like can be used. Coal is preferable because it is relatively easily available and is inexpensive.

The particle size of the raw coal is not particularly limited, and may be any that can be obtained on the general market.

Next, a more detailed description will be given based on an embodiment of the rapid coal pyrolysis method of the present invention.

FIG. 1 is a use state diagram schematically 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, as a coal rapid thermal decomposition apparatus 1 according to the present invention, there is a thermal decomposition reactor 2, and a coal hopper 4 is provided above a 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 preheating tube heater 13 are arranged as heaters along the entire circumference of the pyrolysis reactor 2 and the gas preheating pipe 6 with a certain distance from the side surface outer peripheral portions.

A coal product outlet 14 is provided in the lower portion of the thermal decomposition reactor 2, and the product outlet 14 and the char vessel 15 are connected by a pipe 16. 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 pipes 22, 23, 24, 25, respectively.
Connected by 26 and 27. In addition, the pipe 16
A pipe 28 for heat exchange is installed on the outer peripheral portion of the pipe 2.
One end of 8 is connected to the path of the pipe 11 by a 3-port switching valve 29, and a blower 30 is provided on the path of the pipe 28, and the other end of the pipe 28 is connected to the pipe 2
7 and 3 port switching valve 31 are connected. 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 rapid coal pyrolysis apparatus 1 having the above-mentioned structure, the yield of the desired gas, liquid or solid product can be obtained as needed without changing the coal brand based on the method of the present invention. In order to control the product freely so that it can be increased or changed, in order to rapidly pyrolyze the radiation-treated coal, the coal hopper 4 is first charged with the radiation-treated coal. Then, it is 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. It can also be used for adjusting the dropping and charging speed of the coal particles into the vessel 2.

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 Then, the thermal decomposition treatment is performed by dropping the inside of the thermal decomposition reactor 2.

Thereafter, 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 the solid component (mainly char) in the coal product is collected by the char vessel 15, Subsequently, the solid component in the coal product, which is sent to the cyclone 17 and partially remains in the gasification component as the product of coal, is completely collected by the char vessel 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 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.

Regarding the particle size of the coal particles which have been radiated with the radiation and crushed by the coal hopper 4, coal melts during rapid heating, causing a melting phenomenon in which the coal particles adhere to each other or to the inner wall of the pyrolysis reaction tube. In general, the thickness is 500 μm or less, preferably 100 μm or less so that the coal can be smoothly supplied.

Next, as the gas preheated by the gas preheating pipe 6, an inert or reducing gas can be used. As the inert gas, for example, nitrogen gas or the like is used, and as the reducing gas, hydrogen, carbon monoxide, or the like is used. Benzene produced by continuous operation of the coal rapid thermal decomposition apparatus 1, Toluene, 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.

As the rapid pyrolysis conditions used in the rapid coal pyrolysis method according to the present invention, when the coal particles fall in the pyrolysis reactor 2, the reactor internal pressure is usually 10 atm or less, preferably Is from atmospheric pressure to 5 atm, and the rate of temperature rise 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 / mi
n, and the maximum temperature of the atmospheric gas in the reactor 2 (corresponding to the final temperature of coal particles) is usually 700 to 1
100 ° C., preferably 700 to 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. is there. Rapidly decomposing coal particles that have been previously irradiated with radiation under the above conditions to change the coal type of the coal raw material to be used without performing under high pressure (50 atm or more) as in the past. In addition, the yield of the target gas, liquid or solid product can be increased, and the product can be controlled freely. In addition, 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.

[0032]

[Equation 1]

In the above formula 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.

[0034]

EXAMPLES Examples of the present invention will be described below.

Example 1 As the raw material coal, Australian steam coal, which is relatively easy to obtain and inexpensive, was used with a volatile content of 35%. As the radiation irradiating device, a fixed device, which is provided in a water layer whose periphery is shielded by lead and transmits only cylindrical γ-rays, is loaded with a cobalt 60 radiation source and is irradiated with an object to be irradiated (installed in a specific atmosphere). An apparatus having a structure in which the irradiated object is put in and taken out of the cylindrical hollow portion by suspending the coal) from the upper part of the water tank and adjusting the amount is used.

Before the coal is rapidly pyrolyzed by using the above apparatus, 1 kg of the coal is made of stainless steel of 10 liters in order to irradiate the coal with gamma rays of 10 ⁴ roentgen in hydrogen and air atmospheres respectively. After placing in a container and replacing the inside of the container with a hydrogen atmosphere (without replacing in the case of an air atmosphere), the container is closed, and the closed container is hung from the upper part of the water tank, and by adjusting this, the cylindrical hollow portion is formed. After irradiating 10 ⁴ roentgen γ-rays with the hermetically-sealed container left stationary so as to be positioned, the hermetically-sealed container was lifted from a water tank to obtain radiation-irradiated coal.

Next, rapid coal pyrolysis was carried out using the rapid coal pyrolysis apparatus 1 used in the rapid coal pyrolysis method shown in FIG.

In the first embodiment, first, the coal which has been subjected to the irradiation treatment with the above-mentioned radiation is supplied to the coal hopper 4 at a coal supply amount of 5 kg.
/ Hr, then the coal was crushed by the coal hopper 4 and powdered coal particles crushed to a particle size of 100 μm or less were dropped into the pyrolysis reactor 2 from the coal hopper 4 through the feeder 3 . Then, the coal particles dropped into the pyrolysis reactor 2 heated so that the maximum temperature of the atmospheric gas reaches 800 ° C. are
Coal gas produced by the thermal decomposition reaction preheated to about 900 ° C is circulated at 40 liters / min (using nitrogen gas until coal gas is produced) under a reducing (inert) atmosphere, The heating rate is 1 as pressure
Pyrolysis treatment was carried out for 2 hours for each of the radiation-treated coals in hydrogen and air atmospheres at a temperature of 0 ³ ° C / min and a residence time of 2 sec.

Thereafter, char (solid component) and tar component (for the tar component, respectively) for each rapid thermal treatment of coal which has been subjected to radiation treatment in hydrogen and air atmospheres, respectively.
Further, by distilling at 220 ° C., light tar and heavy tar components are separated), low temperature gas components (benzene, toluene, xylene (BTX) and hydrocarbon gas (HC
G)) was measured.

The yields of the rapid pyrolysis products of the obtained coal are shown in Table 1.

Comparative Example 1 β of the coal obtained in Example 1 before the rapid thermal decomposition of the coal
Rapid thermal decomposition was performed using the coal rapid thermal decomposition apparatus 1 in the same manner as in Example 1 except that the line irradiation treatment was not performed.

After that, char (solid component) and tar component obtained by rapid thermal treatment of unirradiated coal (the tar component is further distilled at 220 ° C. to separate into light tar and heavy tar component). , Low temperature gas components (benzene, toluene, xylene (BTX) and hydrocarbon gas (HCG)) were measured.

The yields of the rapid pyrolysis products of the obtained coal are shown in Table 1.

[0044]

[Table 1]

From the results shown in Table 1 above, when irradiation was not performed, light tar was 5% by weight, heavy tar was 10% by weight, gas and char were 31% by weight and 54% by weight, respectively. On the other hand, with coal irradiated with 10 ⁴ roentgen radiation in a hydrogen (reducing) atmosphere, the yields of light tar and gas were significantly increased, while on the other hand, 10 ⁴ roentgen irradiation was irradiated in an air (oxidizing) atmosphere. On the contrary, in the case of coal, it was confirmed that the yields of char and heavy tar increased.

[0046]

According to the present invention, in the rapid pyrolysis of coal, the control of the rapid pyrolysis products can be performed according to the usage pattern without changing the coal brand. As a result, the coal storage facility and the crushing facility can be significantly saved, and a highly economical rapid coal pyrolysis process can be realized.

[Brief description of drawings]

FIG. 1 is a use state diagram schematically showing a configuration of an embodiment of a coal rapid pyrolysis apparatus 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

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C10J 3/46 G 3/72 D

Claims (4)

[Claims] 1. A method for rapid pyrolysis of coal, which comprises irradiating the coal with radiation of 10 ³ roentgen or more and then rapidly pyrolyzing the coal. 2. The rapid pyrolysis method for coal according to claim 1, wherein in the rapid pyrolysis step for coal, the coal is rapidly heated at a temperature rise rate of 10 ³ ° C./min or more at 10 atmospheric pressure or less. . 3. The rapid coal pyrolysis method according to claim 1, wherein the coal in the rapid coal pyrolysis step is in the form of particles having a particle size of 500 μm or less. 4. The rapid coal pyrolysis method according to claim 1, wherein the maximum temperature of the atmospheric gas in the coal rapid pyrolysis step is 700 to 1100 ° C.