COAL PYROLYSIS DEVICE

The present invention relates to a coal pyrolysis device.

Low grade coal (low rank coal) with a high moisture content such as lignite and subbituminous coal has a low calorific content per unit weight, and therefore such coal is dried and pyrolyzed by heating and then modified in a low-oxygen atmosphere so that the surface activity is reduced, whereby the low grade coal is turned into modified coal having a high calorific content per unit weight while preventing spontaneous combustion.

Here, direct heating type devices that directly heat dried coal with a heating gas (see Patent Documents 1, 2) and indirect heating type devices that indirectly heat dried coal with a heating gas are known as coal pyrolysis devices for pyrolysis of dried coal obtained by drying low grade coal as described above. The indirect heating type of device includes, for example, the rotary kiln type device that includes a fixed supported outer cylinder (jacket), and a rotatably supported inner cylinder on the inside of the outer cylinder. In such a coal pyrolysis device, heating gas is supplied within the outer cylinder (between the outer cylinder and the inner cylinder), and the dried coal is supplied to a first end side of the inner cylinder. By rotating the inner cylinder, the dried coal is heated and pyrolyzed while being agitated and moving from the first end side of the inner cylinder to a second end side. The pyrolyzed coal and the pyrolyzed gas are output from the second end side of the inner cylinder.

Patent Document 1: Japanese Unexamined Patent Application Publication No. 561-64788A

Patent Document 2: Japanese Unexamined Patent Application Publication No. 2012-241992A

The pyrolyzed gas includes not only water vapor, carbon dioxide, low molecular weight hydrocarbons (for example, methane, ethane, and the like), tar, and the like, but also a minute quantity of sulfur included in the dried coal. In order to promote the release of this minute component in the pyrolysis process, it is necessary to increase the difference in partial pressure between the pyrolyzed gas component in the atmosphere gas within the inner cylinder and the pyrolyzed gas component at the surface of the dried coal. For example, supplying low-oxygen concentration inert gas from the exterior into the inner cylinder to reduce the concentration of pyrolyzed gas in the atmosphere within the inner cylinder can be considered.

Normally nitrogen gas is used as the inert gas, but in order to produce nitrogen gas by separating the nitrogen gas from air, a pressure swing adsorption (PSA) or cryogenic separation device is necessary. The quantity of nitrogen gas consumed by the coal pyrolysis device increases in accordance with the size of the coal pyrolysis device (the quantity of dried coal processed by the coal pyrolysis device), so the capacity of the PSA or cryogenic separation device increases, which increases the plant cost and the electrical power cost for producing the nitrogen gas.

In light of the above, in order to solve the above problems, an object of the present invention is to provide a coal pyrolysis device capable of obtaining at low cost an inert gas (low-oxygen concentration gas) for promoting release of the pyrolyzed gas from the coal.

The coal pyrolysis device according to a first invention for solving the above problems includes: a rotary kiln type coal pyrolysis device main body that rotatably supports an inner cylinder inside an outer cylinder, the rotary kiln type coal pyrolysis device main body being configured to supply coal into the inner cylinder from a first end side of the inner cylinder as well as supplying heating gas into the outer cylinder and rotate the inner cylinder to heat and pyrolyze the coal while moving the coal from the first end side of the inner cylinder to a second end side and agitating the coal, and to output the pyrolyzed coal and pyrolyzed gas from the second end side of the inner cylinder; exhaust means provided connected to the outer cylinder, the exhaust means being for exhausting the heating gas within the outer cylinder; gas extraction means for extracting a portion of the heating gas exhausted by the exhaust gas means; and low-oxygen concentration gas supply means for supplying the heating gas extracted by the gas extraction means into the inner cylinder so that the concentration of oxygen contained in the heating gas is reduced.

The coal pyrolysis device according to a second invention for solving the above problems is the coal pyrolysis device according to the first invention as described above. In such a coal pyrolysis device, the low-oxygen concentration gas supply means include deoxygenation means for removing the oxygen contained in the heating gas, and low-oxygen concentration gas delivery means for delivering the low-oxygen concentration gas obtained from the deoxygenation means into the inner cylinder.

The coal pyrolysis device according to a third invention for solving the above problems is the coal pyrolysis device according to the second invention as described above. In such a coal pyrolysis device, the deoxygenation means include fuel addition means for adding fuel to the heating gas, and a combustion catalyst provided so as to come into contact with the heating gas to which the fuel has been added.

The coal pyrolysis device according to a fourth invention for solving the above problems is the coal pyrolysis device according to the third invention as described above. Such a coal pyrolysis device further includes heating means provided in the gas extraction means, the heating means being for heating the heating gas.

The coal pyrolysis device according to a fifth invention for solving the above problems is the coal pyrolysis device according to the third invention as described above. Such a coal pyrolysis device further includes desulfurization means provided in the exhaust means, the desulfurization means being for removing sulfur oxide contained in the heating gas.

The coal pyrolysis device according to a sixth invention for solving the above problems is the coal pyrolysis device according to the fourth invention as described above. Such a coal pyrolysis device further includes: oxygen concentration measuring means for measuring an oxygen concentration of the low-oxygen concentration gas delivered by the low-oxygen concentration gas delivery means; and fuel addition quantity control means for controlling a quantity of the fuel added by the fuel addition means on the basis of information obtained by the oxygen concentration measuring means so that the oxygen concentration of the low-oxygen concentration gas is 1.5% or less.

The coal pyrolysis device according to a seventh invention for solving the above problems is the coal pyrolysis device according to the second invention as described above. In such a coal pyrolysis device, the deoxygenation means include an alternating combustion device that includes a combustion chamber to which the heating gas is delivered, a burner provided within the combustion chamber, and an alternating type heat exchanger provided within the combustion chamber in a location to which the heating gas is delivered, and fuel addition means for adding fuel to the combustion chamber.

The coal pyrolysis device according to an eighth invention for solving the above problems is the coal pyrolysis device according to the seventh invention as described above. Such coal pyrolysis device further includes: oxygen concentration measuring means for measuring the concentration of oxygen contained in the heating gas delivered by the low-oxygen concentration gas delivery means; and fuel addition quantity control means for controlling a quantity of the fuel added by the fuel addition means on the basis of information obtained by the oxygen concentration measuring means so that the oxygen concentration of the low-oxygen concentration gas is 1.5% or less.

The coal pyrolysis device according to a ninth invention for solving the above problems is the coal pyrolysis device according to the first invention as described above. In such a coal pyrolysis device, the low-oxygen concentration gas supply means include heating gas delivery means for delivering the heating gas extracted by the gas extraction means into the inner cylinder, and fuel addition means for adding fuel to the heating gas delivered into the inner cylinder by the heating gas delivery means.

The coal pyrolysis device according to a tenth invention for solving the above problems is the coal pyrolysis device according to the ninth invention as described above. Such a coal pyrolysis device further includes: heating gas flow rate measuring means for measuring a flow rate of the heating gas delivered by the heating gas delivery means; oxygen concentration measuring means for measuring a concentration of oxygen contained in the heating gas delivered by the heating gas delivery means; and fuel addition quantity control means for controlling a quantity of the fuel added by the fuel addition means on the basis of information obtained by the heating gas flow rate measuring means and the oxygen concentration measuring means so that the oxygen concentration of the low-oxygen concentration gas is 1.5% or less.

According to the coal pyrolysis device of the present invention, it is possible to obtain the inert gas by reducing the concentration of oxygen contained in the heating gas that has indirectly heated the coal, using the low-oxygen concentration gas supply means. The cost of the low-oxygen concentration gas supply means itself and the operating cost thereof are lower than those of a PSA or cryogenic separation device, so the inert gas that promotes release of the pyrolyzed gas from the coal can be obtained at low cost. In the case that generating the inert gas raises the temperature of the inert gas itself, the coal within the coal pyrolysis device main body can be heated by the inert gas, which allows the size of the coal pyrolysis device main body to be reduced.

The following is a description of embodiments of the coal pyrolysis device according to the present invention based on the drawings, but the present invention is not limited to only the following embodiments described based on the drawings.

The following is a description of the first embodiment of the coal pyrolysis device according to the present invention based on FIG. 1.

As illustrated in FIG. 1, a coal pyrolysis device 100 according to the present embodiment includes a coal pyrolysis device main body 110 that is coal pyrolysis means for obtaining pyrolyzed coal 2 by indirectly heating dried coal 1 with a heating gas 11. The coal pyrolysis device main body 110 includes a hopper 111, an inner cylinder (main body trunk) 112, an outer cylinder (jacket) 113, and a chute 114. The hopper 111 is a device that receives the dried coal 1 and supplies the dried coal 1 into a first end side (proximal end side) of the inner cylinder 112. The inner cylinder 112 is rotatably supported. The inner cylinder 112 is a device that rotates to cause the dried coal 1, which has been supplied into the inner cylinder 112, to move from the first end side to a second end side of the inner cylinder 112 while agitating the dried coal 1. The outer cylinder 113 is fixed and supported so as to cover the outer peripheral surface of the inner cylinder 112 while enabling the inner cylinder 112 to rotate. The outer cylinder 113 is a device that heats the inner cylinder 112 with the heating gas 11, which is a heating medium, that is delivered to the inside of the outer cylinder 113. The chute 114 is a device that is connected to the second end side (distal end side) of the inner cylinder 112 so that the inner cylinder 112 can rotate and is configured to drop the pyrolyzed coal 2, which is obtained by subjecting the dried coal 1 to indirect heating with the heating gas 11 to pyrolyze the dried coal 1, down from the second end side of the inner cylinder 112. In other words, the coal pyrolysis device main body 110 is a rotary kiln type device.

For example, low grade coal (low rank coal) having a high water content such as lignite or subbituminous coal that has been supplied to a dryer (not illustrated on the drawings), and that is dried by hot gas (150° C. to 500° C.) that is distributed within the dryer so that the water content is substantially 0% can be used as the dried coal 1.

A first end side (proximal end side) of a pyrolyzed gas exhaust line 115 is connected to the top portion of the chute 114 of the coal pyrolysis device main body 110. A second end side (distal end side) of the pyrolyzed gas exhaust line 115 is coupled to a combustion furnace 116, which is heating gas generation means. Therefore, pyrolyzed gas (thermal decomposition gas) 15 released from the dried coal 1 when the dried coal 1 is indirectly heated by the heating gas 11, and that includes water vapor, carbon dioxide, low molecular weight hydrocarbons, tar, and the like is exhausted from within the inner cylinder 112 to the combustion furnace 116 via the chute 114 and the pyrolyzed gas exhaust line 115.

The combustion furnace 116 is connected to a first end side (proximal end side) of a heating gas delivery line 117. The combustion furnace 116 is connected to a second end side (distal end side) of an exhaust gas recirculation line 121 that is described in detail later. A second end side (distal end side) of the heating gas delivery line 117 is connected to the inside of the outer cylinder 113 of the coal pyrolysis device main body 110. The pyrolyzed gas 15 has a combustion heat value of 5 to 15 MJ/Nm³, and the pyrolyzed gas 15 delivered to the combustion furnace 116 is processed by combustion together with supporting fuel (combustion improver) 16 such as natural gas, and the exhaust gas 13. Therefore, the heating gas (combustion gas) 11 generated within the combustion furnace 116 is delivered to the inside of the outer cylinder 113 via the heating gas delivery line 117.

The outer cylinder 113 is connected to a first end side (proximal end side) of an exhaust gas exhaust line 118. A boiler 118a, a flow rate adjustment valve 118b, and an exhaust fan 118c are provided from a first end side of the exhaust gas exhaust line 118. The waste heat of heating gas 12 after heating the inner cylinder 112 is recovered by the boiler 118a. By controlling the flow rate adjustment valve 118b and the exhaust fan 118c, the heating gas 12 after heating the inner cylinder 112 flows from the first end side to the second end side (distal end side) of the exhaust gas exhaust line 118.

A first end side (proximal end side) of a heating gas bypass line 119 is connected between the proximal end side and the distal end side of the heating gas delivery line 117. A second end side (distal end side) of the heating gas bypass line 119 is connected to the exhaust line 118 between the flow rate adjustment valve 118b and the exhaust fan 118c. A boiler 119a and a flow rate adjustment valve 119b are provided on the heating gas bypass line 119 from a first end side thereof. The waste heat of the heating gas 11 is recovered by the boiler 119a. By controlling the flow rate adjustment valve 119b and the exhaust fan 118c, a portion of the heating gas 11 generated within the combustion furnace 116 is fed to the second end side (distal end side) of the exhaust gas exhaust line 118 from the heating gas delivery line 117 via the heating gas bypass line 119.

Therefore, by controlling the flow rate adjustment valves 118b, 119b and the exhaust fan 118c, the exhaust gas 13 that is a mixed gas from mixing the heating gases 11, 12 is fed to the second end side (distal end side) of the exhaust gas exhaust line 118.

An exhaust gas processing device 130 that processes the exhaust gas 13 is provided on the second end side (distal end side) of the exhaust gas exhaust line 118.

The exhaust gas processing device 130 includes a denitrification device (denitrification means) 131, an electrical dust collector (dust removal means) 132, and a desulfurization device (desulfurization means) 133.

The denitrification device 131 removes nitrogen oxides (N0x) contained in the exhaust gas 13. For example, a device that reduces nitrogen oxides such as nitric oxide to nitrogen gas by spraying an aqueous solution of ammonium chloride (not illustrated on the drawings) into the exhaust gas 13 can be used as the denitrification device 131.

The electrical dust collector 132 separates and removes fine particulate solid matter such as dust included in the exhaust gas 13.

The desulfurization device 133 removes sulfur oxides (S0x) included in the exhaust gas 13. For example, a wet type device that converts sulfur oxides such as sulfur dioxide into calcium sulfide or the like by blowing a calcium carbonate slurry (not illustrated on the drawings) into the exhaust gas 13 can be used as the desulfurization device 133. In this way, the SOx concentration of the exhaust gas 13 can be reduced to 50 ppm or less, so the reduction in performance due to S poisoning the combustion catalyst that is described later can be minimized, and the increase in operating cost due to replacement of the combustion catalyst can be minimized.

Therefore, the NOx, dust, and SOx is removed from the exhaust gas 13 by processing in the devices 131 to 133 as described above. The exhaust gas 13 that has been processed in this way is exhausted outside the system.

A first end side (proximal end side) of the exhaust gas recirculation line 121 is connected to the exhaust gas exhaust line 118 between the exhaust fan 118c and the denitrification device 131. The second end side (distal end side) of the exhaust gas recirculation line 121 is connected to the combustion furnace 116. A flow rate adjustment valve 121a is provided on the exhaust gas recirculation line 121. By controlling the exhaust fan 118c and the flow rate adjustment valve 121a, a portion of the exhaust gas 13 flowing through the exhaust gas exhaust line 118 is recirculated to the combustion furnace 116 via the exhaust gas recirculation line 121.

The coal pyrolysis device main body 110 as described above further includes an inert gas generation device 140 that generates inert gas 14 for promoting the release of pyrolyzed gas 15 from the dried coal 1.

The inert gas generation device 140 includes an exhaust gas extraction line 141 provided connected at a first end side (proximal end side) thereof between the second end side (distal end side) of the exhaust gas exhaust line 118 and the desulfurization device 133. The second end side (distal end side) of the exhaust gas extraction line 141 is connected to a gas inlet of a combustion catalyst deoxygenation device (deoxygenation device) 142. A flow rate adjustment valve 141a, an extraction fan 141b, and a heat exchanger (heating means) 143 are provided on the exhaust gas extraction line 141 from the first end side (proximal end side) thereof. By controlling the flow rate adjustment valve 141a and the extraction fan 141b, a portion of the exhaust gas 13 that has passed through the desulfurization device 133 flows to the exhaust gas exhaust line 141 via the exhaust gas exhaust line 118.

A first end side (proximal end side) of an exhaust gas bypass line 144 is connected to the exhaust gas exhaust line 141 between the extraction fan 141b and the heat exchanger 143. A second end side (distal end side) of the exhaust gas bypass line 144 is connected to the exhaust gas extraction line 141 between the heat exchanger 143 and the combustion catalyst deoxygenation device 142. A flow rate adjustment valve 144a is provided on the exhaust gas bypass line 144. By controlling the flow rate adjustment valves 141a, 144a, and the extraction fan 141b, the proportion of the exhaust gas 13 flowing to the combustion catalyst deoxygenation device 142 via the heat exchanger 143, and the exhaust gas 13 flowing to the combustion catalyst deoxygenation device 142 via the exhaust gas bypass line 144 can be adjusted, so the temperature of the exhaust gas 13 flowing to the combustion catalyst deoxygenation device 142 is adjusted.

A first end side (distal end side) of an oxygen consuming fuel supply line 145 that delivers an oxygen consuming fuel 17 for consuming oxygen in the exhaust gas 13, for example a hydrocarbon fuel such as natural gas, is provided connected to a gas inlet of the combustion catalyst deoxygenation device 142. A tank 146 that stores the oxygen consuming fuel 17 is provided connected to a second end side (proximal end side) of the oxygen consuming fuel delivery line 145. A flow rate adjustment valve 145a is provided on the oxygen consuming fuel delivery line 145.

The combustion catalyst deoxygenation device 142 includes a pre-mixing chamber (not illustrated on the drawings) capable of generating a pre-mixed gas that is a mixture of the exhaust gas 13 and the oxygen consuming fuel 17, and a combustion catalyst (not illustrated on the drawings) filling a location adjacent to the pre-mixing chamber and coming into contact with the pre-mixed gas, that causes the oxygen in the exhaust gas 13 to react with the oxygen consuming fuel 17 to consume the oxygen.

For example, a base material formed in a honeycomb shape and the catalyst that includes a noble metal provided on the base material can be used as the combustion catalyst. For example, the base material can be made of cordierite. The noble metal may be platinum or palladium, for example. The method of providing the noble metal on the base material can be, for example, an impregnation and supporting method or a coating method.

A first end side (proximal end side) of an inert gas delivery line 147 that delivers the inert gas 14 obtained by reducing the oxygen concentration of the exhaust gas 13 obtained from the combustion catalyst deoxygenation device 142 is provided connected to a gas outlet of the combustion catalyst deoxygenation device 142. A second end side (distal end side) of the inert gas delivery line 147 is connected to a first end side (proximal end side) of the inner cylinder 112 of the coal pyrolysis device main body 110 via the heat exchanger 143. As described in detail later, the temperature of the inert gas 14 is raised to 550° C. to 750° C., and the exhaust gas 13 can be preheated to the ignition temperature 150° C. to 350° C. of the fuel 17 by the inert gas 14 in the heat exchanger 143. The inert gas 14 is delivered to the inner cylinder 112 of the coal pyrolysis device main body 110.

A temperature sensor 141c that can measure the temperature of the exhaust gas 13 flowing through the exhaust gas extraction line 141 is provided between the distal end side of the exhaust gas extraction line 141 and the heat exchanger 143. The temperature sensor 141c is connected to the flow rate adjustment valve 144a of the exhaust gas bypass line 144 via a temperature signal cable. The degree of opening of the flow rate adjustment valve 144a can be adjusted on the basis of information (exhaust gas 13 temperature) obtained by the temperature sensor 141c.

An oxygen sensor (oxygen concentration measurement means) 147a capable of measuring the oxygen concentration of the inert gas 14 flowing through the inert gas supply line 147 is provided on the inert gas delivery line 147.

The oxygen sensor 147a is connected to the flow rate adjustment valve 145a provided on the oxygen consuming fuel delivery line 145 via an oxygen concentration signal cable. The degree of opening of the flow rate adjustment valve 145a can be adjusted on the basis of information (oxygen concentration of the inert gas 14) obtained by the oxygen sensor 147a. In other words, the coal pyrolysis device 100 includes a control device (fuel addition quantity control means) that is not illustrated on the drawings, and the control device can control the quantity of oxygen consuming fuel 17 added by the oxygen consuming fuel delivery line 145, the flow rate adjustment valve 145a, and the tank 146 so that the oxygen concentration of the inert gas 14 is, for example, 1.5% or less, on the basis of the information (oxygen concentration of the inert gas 14) obtained by the oxygen sensor 147a.

In the present embodiment as described above, exhaust means include the exhaust gas exhaust line 118, the boiler 118a, the flow rate adjustment valve 118b, the exhaust fan 118c, the exhaust gas processing device 130, and the like. Gas extraction means include the exhaust gas extraction line 141, the flow rate adjustment valve 141a, the extraction fan 141b, the heat exchanger 143, the exhaust gas bypass line 144, the flow rate adjustment valve 144a, and the like. Fuel addition means include the oxygen consuming fuel delivery line 145, the flow rate adjustment valve 145a, the tank 146, and the like. Deoxygenation means include the combustion catalyst deoxygenation device 142, the fuel addition means, and the like. Low-oxygen concentration gas delivery means include the exhaust gas extraction line 141, the flow rate adjustment valve 141a, the extraction fan 141b, the inert gas delivery line 147, and the like. Low-oxygen concentration gas supply means include the low-oxygen concentration gas delivery means, the deoxygenation means, and the like. The coal pyrolysis device 100 includes the coal pyrolysis device main body 110, the exhaust means, the gas extraction means, the low-oxygen concentration gas supply means, the fuel addition control means, and the like.

The following is a description of a coal pyrolysis processing method for pyrolysis of dried coal 1 using the coal pyrolysis device 100 according to the present embodiment configured in this way.

When dried coal 1 is fed into the hopper 111 of the coal pyrolysis device main body 110, the dried coal 1 within the hopper 111 is supplied from the first end side (proximal end side) to the interior of the inner cylinder 112. The dried coal 1 within the inner cylinder 112 is moved from the first end side (proximal end side) to the second end side (distal end side) of the inner cylinder 112 by the rotation of the inner cylinder 112. The inner cylinder 112 is heated by the heating gas 11 delivered within the outer cylinder 113, so when the dried coal 1 is moving from the first end side to the second end side of the inner cylinder 112, the dried coal 1 is indirectly heated (300° C. to 500° C.) by the heating gas 11. In this way, the pyrolyzed gas (thermal decomposition gas) 15 that includes water vapor, carbon dioxide, low molecular weight hydrocarbons, tar, and the like, together with minute quantities of sulfur is released from the dried coal 1, and the separated pyrolyzed coal 2 is obtained.

The pyrolyzed coal 2 drops down from the second end side of the inner cylinder 112 via the chute 114. The pyrolyzed coal 2 that has dropped down from the chute 114 is supplied to a cooler that is not illustrated on the drawings, for example, and is cooled (150° C. to 200° C.). Active sites (radicals) produced by pyrolysis are inactivated by an inactivation processing device (not illustrated on the drawings), then the product is mixed with binder and water by a mixing device (not illustrated on the drawings), and coal briquettes are formed by compression and molding in a molding device (not illustrated on the drawings).

The pyrolyzed gas 15 separated and removed from the dried coal 1 is delivered to the combustion furnace 116 via the pyrolyzed gas exhaust line 115.

Within the combustion furnace 116, the heating gas (combustion gas) 11 is generated by combustion processing of the pyrolyzed gas 15 together with the supporting fuel 16 and the exhaust gas 13. In the combustion furnace 116, the ratio of the supporting fuel 16 and the air flow rate is controlled by controlling the combustion air ratio, and normally the combustion excess air ratio is set to 1.0 or higher in order to prevent generation of unburned components such as soot, and prevent lowering of the combustion efficiency. Therefore, the oxygen concentration in the heating gas (combustion gas) 11 is in the order of 2 to 5%. By controlling the flow rate adjustment valve 118b and the exhaust fan 118c, a portion of the heating gas 11 is delivered to within the outer cylinder 113 through the heating gas delivery line 117, and after the inner cylinder 112 is heated, the heating gas 12 flows to the distal end side of the exhaust gas exhaust line 118 from within the outer cylinder 113. The remainder of the heating gas 11 is delivered to the exhaust gas exhaust line 118 via the heating gas bypass line 119. The heating gas 12, from which the waste heat has been recovered by the boiler 118a, has a specific temperature (for example, 350° C.). The heating gas 11 flowing through the heating gas bypass line 119, from which the waste heat has been recovered by the boiler 119a, has a specific temperature (for example, 350° C.). Exhaust gas (mixed gas) 13 that is a mixture of the heating gas 12 from which the waste heat has been recovered in the boiler 118a and the heating gas 11 from which the waste heat has been recovered in the boiler 119a is delivered to the second end side (distal end side) of the exhaust gas exhaust line 118 by the exhaust fan 118c, and is processed in the exhaust gas processing device 130.

A portion of the exhaust gas 13 that flows through the exhaust gas exhaust line 118 is recirculated to the combustion furnace 116 via the exhaust gas recirculation line 121, by controlling the flow rate adjustment valve 121a.

The exhaust gas 13 that is not circulated to the exhaust gas recirculation line 121 but flows to the distal end side of the exhaust gas exhaust line 118 has NOx removed by the denitrification device 131, solid matter removed by the electrical dust collector 132, and SOx removed by the desulfurization device 133, and is released outside the system.

When producing the pyrolyzed coal 2 from the dried coal 1 in this way, the quantity of inert gas that promotes release of the pyrolyzed gas 15 from the dried coal 1 increases in accordance with the quantity of pyrolyzed coal 2 produced, and the capacity of the PSA or cryogenic separation device that produces the inert gas is increased accordingly, so the plant cost and the electrical power cost are increased.

In the coal pyrolysis device 100 according to this embodiment that addresses this problem, in order to reuse the exhaust gas 13 exhausted outside the system through the exhaust gas exhaust line 118, the following operation is additionally carried out.

By controlling the flow rate adjustment valve 141a and the extraction fan 141b provided on the exhaust gas extraction line 141, a portion of the exhaust gas 13 that has passed through the desulfurization device 133 is not exhausted outside the system via the exhaust gas exhaust line 118 but flows to the exhaust gas extraction line 141. By controlling the flow rate adjustment valve 144a on the basis of the information (temperature of the exhaust gas 13) obtained from the temperature sensor 141c, the proportion of the exhaust gas 13 flowing to the combustion catalyst deoxygenation device 142 via the heat exchanger 143, and the exhaust gas 13 flowing to the combustion catalyst deoxygenation device 142 via the exhaust gas bypass line 144 is adjusted, so the exhaust gas 13, which has been preheated to the ignition temperature 150° C. to 350° C. of the oxygen consuming fuel 17 in the heat exchanger 143, flows to the combustion catalyst deoxygenation device 142. By providing the exhaust gas bypass line 144 and the flow rate adjustment valve 144a, the preheating temperature of the exhaust gas 13 can be adjusted accordingly, even if the ignition temperature of the oxygen consuming fuel 17 rises due to degradation in the performance of the combustion catalyst of the combustion catalyst deoxygenation device 142 with time.

By controlling the flow rate adjustment valve 145a on the basis of the information (oxygen concentration of the inert gas 14) obtained from the oxygen sensor 147a, a specific quantity of oxygen consuming fuel 17 is delivered to the combustion catalyst deoxygenation device 142. In other words, the oxygen concentration of the inert gas 14 can be reduced to a specific value or lower by feedback control. Preferably, the specific value is 1.5% or less. In this way, the pyrolysis loss due to the oxygen in the inert gas 14 reacting with the dried coal 1 can be minimized.

In the combustion catalyst deoxygenation device 142, the mixed gas obtained by pre-mixing the exhaust gas 13 and the oxygen consuming fuel 17 comes into contact with the combustion catalyst, which causes the oxygen consuming fuel 17 to burn and the oxygen in the exhaust gas 13 to be consumed, to reduce the oxygen concentration of the exhaust gas 13. At this time, the temperature of the inert gas 14 formed by reducing the oxygen concentration of the exhaust gas 13 is raised to 550° C. to 750° C. by the heat of reaction. The inert gas 14 is supplied to the inner cylinder 112 of the coal pyrolysis device main body 110 via the inert gas delivery line 147. The quantity of inert gas 14 to be delivered is adjusted to 0.1 N·m³to 0.3 N·m³per 1 kg of dried coal 1 supplied to the inner cylinder 112. In this way, the partial pressure of the pyrolyzed gas 15 at the surface of the dried coal 1 is reduced, which promotes the release of the pyrolyzed gas 15 from the dried coal 1.

Therefore, according to the coal pyrolysis device 100 of the present embodiment, it is possible to process the exhaust gas 13 produced by the coal pyrolysis device main body 110 in the combustion catalyst deoxygenation device 142 to obtain the inert gas 14. The cost of the combustion catalyst deoxygenation device 142 itself and the operating cost thereof are lower than those of a PSA or cryogenic separation device, so the inert gas 14 that promotes release of the pyrolyzed gas 15 from the dried coal 1 can be obtained at low cost.

Also, the temperature of the inert gas 14 obtained from the combustion catalyst deoxygenation device 142 is about 550° C. to 750° C., so the dried coal 1 within the inner cylinder 112 is directly heated by the inert gas 14 in addition to being indirectly heated by the heating gas 11. In other words, in addition to the heating gas 11, the inert gas 14 can be used as the heat source (pyrolysis heat source) when pyrolyzing the dried coal 1. In this way, the quantity of heat supplied from outside the coal pyrolysis device main body 110 as the pyrolysis heat source, in other words the flow rate of the heating gas 11, can be reduced, and the heat load of the coal pyrolysis device main body 110 can be reduced. As a result, the total length of the outer cylinder 113 (coal pyrolysis device main body 110) can be reduced compared with when the heating gas 11 only is used as the pyrolysis heat source.

The following is a description of a second embodiment of the coal pyrolysis device according to the present invention based on FIGS. 2A and 2B.

The present embodiment is configured by modifying the deoxygenation device provided in the first embodiment as described above and illustrated in FIG. 1. The rest of the configuration is generally the same as that described above and illustrated in FIG. 1, so the same equipment is given the same reference numeral and duplicated descriptions are omitted as appropriate.

As illustrated in FIGS. 2A and 2B, a coal pyrolysis device 200 according to the present embodiment includes an inert gas generation device 240 that generates inert gas 24 for promoting the release of pyrolyzed gas 15 from dried coal 1.

The inert gas generation device 240 includes an exhaust gas extraction line 241 provided connected at a first end side (proximal end side) thereof between the second end side (distal end side) of the exhaust gas exhaust line 118 and the desulfurization device 133. The second end side (distal end side) of the exhaust gas extraction line 241 is connected to a gas inlet of an alternating combustion deoxygenation device (deoxygenation device) 242. A flow rate adjustment valve 241a and an extraction fan 241b are provided on the exhaust gas extraction line 241 from the first end side (proximal end side) thereof. By controlling the flow rate adjustment valve 241a and the extraction fan 241b, a portion of the exhaust gas 13 that has passed through the desulfurization device 133 flows to the exhaust gas extraction line 241 via the exhaust gas exhaust line 118.

A first end side (distal end side) of an oxygen consuming fuel delivery line 245 that delivers an oxygen consuming fuel 27 for consuming oxygen in the exhaust gas 13, for example, a hydrocarbon fuel such as natural gas, is provided connected in the vicinity of a gas inlet (a side wall in the vicinity of the top portion of a device main body 242b that is described later) of the alternating combustion deoxygenation device 242. A tank 246 that stores the oxygen consuming fuel 27 is provided connected to a second end side (proximal end side) of the oxygen consuming fuel supply line 245. A flow rate adjustment valve 245a is provided on the oxygen consuming fuel delivery line 245.

The alternating combustion deoxygenation device 242 includes the device main body 242b provided with a combustion chamber 242a in the interior thereof. A burner 242c is provided in the lower portion of the device main body 242b. Temperature maintaining fuel 28 and temperature maintaining fuel combustion air 29 are supplied to the burner 242c. The temperature maintaining fuel 28 is burned in the burner 242c, thereby maintaining the temperature of the atmosphere in the combustion chamber 242a at a high temperature of about 1200° C. In this way, even when the concentration of oxygen in the exhaust gas 13 is a low concentration of 2 to 5%, the oxygen consuming fuel 27 can be stably burned with the low concentration of oxygen contained in the exhaust gas 13.

An alternating type heat exchanger 242d is provided in the device main body 242b. The alternating type heat exchanger 242d includes a first heat exchanger main body 242da and a second heat exchanger main body 242db that are provided adjacently. The second end side (distal end side) of the exhaust gas extraction line 241 is connected to the first heat exchanger main body 242da. A first end side (proximal end side) of an inert gas delivery line 247 is connected to the second heat exchanger main body 242db. A rotary valve 242e is provided in the vicinity of the distal end side of the exhaust gas extraction line 241 and in the vicinity of the proximal end side of the inert gas supply line 247, so that the distal end side of the exhaust gas extraction line 241 and the proximal end side of the inert gas delivery line 247 can be switched using the rotary valve 242e. In this way, the exhaust gas 13 delivered to the alternating combustion deoxygenation device 242 from the exhaust gas extraction line 241 is preheated to 800° C. to 1000° C. by the alternating type heat exchanger 242d provided at the gas inlet of the alternating combustion deoxygenation device 242 and supplied to the combustion chamber 242a of the alternating combustion deoxygenation device 242.

By burning the oxygen consuming fuel 27 in the burner 242c together with the temperature maintaining fuel 28, the oxygen in the exhaust gas 13 is consumed and the inert gas 24, which is a gas with a low-oxygen concentration, is generated.

A second end side (distal end side) of the inert gas delivery line 247 is connected to the first end side (proximal end side) of the inner cylinder 112 of the coal pyrolysis device main body 110. In this way, the inert gas 24 whose temperature has become 70° C. to 150° C. in the alternating type heat exchanger 242d provided at the gas outlet of the alternating combustion deoxygenation device 242 is delivered to the inner cylinder 112 of the coal pyrolysis device main body 110.

An oxygen sensor (oxygen concentration measuring means) 247a capable of measuring the oxygen concentration of the inert gas 24 flowing through the inert gas delivery line 247 is provided on the inert gas supply line 247.

The oxygen sensor 247a is connected to the flow rate adjustment valve 245a provided on the oxygen consuming fuel delivery line 245 via an oxygen concentration signal cable. The degree of opening of the flow rate adjustment valve 245a can be adjusted on the basis of information (oxygen concentration of the inert gas 24) obtained by the oxygen sensor 247a. In other words, the coal pyrolysis device 200 includes a control device (fuel addition control means) that is not illustrated on the drawings, and the control device can control the quantity of oxygen consuming fuel 27 added by the oxygen consuming fuel delivery line 245, the flow rate adjustment valve 245a, and the tank 246 so that the oxygen concentration of the inert gas 24 is, for example, 1.5% or less, on the basis of the information (oxygen concentration of the inert gas 24) obtained by the oxygen sensor 247a.

In the present embodiment as described above, exhaust means include the exhaust gas extraction line 241, the flow rate adjustment valve 241a, the extraction fan 241b, and the like. Fuel addition means include the oxygen consuming fuel delivery line 245, the flow rate adjustment valve 245a, the tank 246, and the like. Deoxygenation means include the alternating combustion deoxygenation device 242, the fuel addition means, and the like. Low-oxygen concentration gas delivery means include the exhaust gas extraction line 241, the flow rate adjustment valve 241a, the extraction fan 241b, the inert gas delivery line 247, and the like. Low-oxygen concentration gas supply means include the low-oxygen concentration gas delivery means, the deoxygenation means, and the like. The coal pyrolysis device 200 includes the coal pyrolysis device main body 110, the exhaust means, the gas extraction means, the low-oxygen concentration gas supply means, the fuel addition control means, and the like. The other means each include similar equipment as the first embodiment described above.

In the coal pyrolysis device 200 according to the present embodiment that includes the inert gas generation device 240 as described above, it is possible to produce the pyrolyzed coal 2 from the dried coal 1 by causing the same central operation as the coal pyrolysis device 100 according to the first embodiment as described previously.

Also, by controlling the flow rate adjustment valve 241a and the extraction fan 241b provided on the exhaust gas extraction line 241, a portion of the exhaust gas 13 that has passed through the desulfurization device 133 via the exhaust gas exhaust line 118 is not exhausted outside the system but flows to the exhaust gas extraction line 241. By controlling the flow rate adjustment valve 245a on the basis of the information (oxygen concentration of the inert gas 24) obtained from the oxygen sensor 247a, a specific quantity of oxygen consuming fuel 27 is delivered to the alternating combustion deoxygenation device 242. In other words, the oxygen concentration of the inert gas 24 can be reduced to a specific value or lower by feedback control. Preferably, the specific value is 1.5% or less. In this way, the pyrolysis loss due to the oxygen in the inert gas 24 reacting with the dried coal 1 can be minimized.

By preheating the exhaust gas 13 to 800° C. to 1000° C. in the alternating type heat exchanger 242d and delivering it to the combustion chamber 242a within the alternating combustion deoxygenation device 242, the temperature maintaining fuel 28 is burned together with the oxygen consuming fuel 27, the oxygen within the exhaust gas 13 is consumed, and the oxygen concentration of the exhaust gas 13 is reduced. The temperature of the inert gas 24, which is the exhaust gas 13 with a reduced oxygen concentration, becomes 70° C. to 150° C. in the alternating type heat exchanger 242d, and is delivered to the inner cylinder 112 of the coal pyrolysis device main body 110 via the inert gas delivery line 247. The quantity of inert gas 24 to be delivered is adjusted to 0.1 N·m³to 0.3 N·m³per 1 kg of dried coal 1 supplied to the inner cylinder 112. In this way, the partial pressure of the pyrolyzed gas 15 at the surface of the dried coal 1 is reduced, which promotes the release of the pyrolyzed gas 15 from the dried coal 1.

In this way, in the present embodiment, by processing the exhaust gas 13 produced in the coal pyrolysis device main body 110 using the alternating combustion deoxygenation device 242, it can be used as the inert gas 24 to promote the release of the pyrolyzed gas 15 from the dried coal 1.

Therefore, according to the coal pyrolysis device 200 of to the present embodiment, it is possible to process the exhaust gas 13 produced by the coal pyrolysis device main body 110 in the alternating combustion deoxygenation device 242 to obtain the inert gas 24. The cost of the alternating combustion deoxygenation device 242 itself and the operating cost are lower than those of a PSA or cryogenic separation device, so the inert gas 24 that promotes release of the pyrolyzed gas 15 from the dried coal 1 can be obtained at low cost.

Also, the temperature of the inert gas 24 obtained from the alternating combustion deoxygenation device 242 is about 70° C. to 150° C., so the dried coal 1 within the inner cylinder 112 is directly heated by the inert gas 24 in addition to being indirectly heated by the heating gas 11. In other words, in addition to the heating gas 11, the inert gas 24 can be used as the heat source (pyrolysis heat source) when pyrolyzing the dried coal 1. In this way, the quantity of heat supplied from outside the coal pyrolysis device main body 110 as the pyrolysis heat source, in other words, the flow rate of the heating gas 11, can be reduced, and the heat load of the coal pyrolysis device main body 110 can be reduced. As a result, the total length of the outer cylinder 113 (coal pyrolysis device main body 110) can be reduced compared with when the heating gas 11 only is used as the pyrolysis heat source.

The following is a description of a third embodiment of the coal pyrolysis device according to the present invention based on FIG. 3.

The present embodiment is configured by modifying the deoxygenation device provided in the first embodiment as described above and illustrated in FIG. 1. The rest of the configuration is generally the same as that described above and illustrated in FIG. 1, so the same equipment is given the same reference numeral and duplicated descriptions are omitted as appropriate.

As illustrated in FIG. 3, a coal pyrolysis device 300 according to the present embodiment includes an inert gas generation device 340 that generates from the exhaust gas 13 inert gas (not illustrated on the drawings) for promoting the release of pyrolyzed gas 15 from the dried coal 1.

The inert gas generation device 340 includes an exhaust gas extraction line 341 provided connected at a first end side (proximal end side) thereof between the second end side (distal end side) of the exhaust gas exhaust line 118 and the desulfurization device 133.

A second end side (distal end side) of the inert gas supply line 341 is connected to the first end side (proximal end side) of the inner cylinder 112 of the coal pyrolysis device main body 110. A flow rate adjustment valve 341a and an extraction fan 341b are provided on the exhaust gas extraction line 341 from the proximal end side thereof.

In addition, a flow rate meter (exhaust gas flow rate measuring means) 341c that measures the flow rate of the exhaust gas 13 flowing through the exhaust gas extraction line 341, and an oxygen sensor (oxygen concentration measuring means) 341d that measures the oxygen concentration of the exhaust gas 13 flowing through the exhaust gas extraction line 341 are provided on the exhaust gas extraction line 341.

In addition, a first end side (distal end side) of an oxygen consuming fuel supply line 345 that delivers an oxygen consuming fuel 37 for consuming oxygen in the exhaust gas 13, for example a hydrocarbon fuel such as natural gas, is provided connected to the exhaust gas extraction line 341 between the oxygen sensor 341d and the second end side (distal end side) of the exhaust gas extraction line 341. A tank 346 that stores the oxygen consuming fuel 37 is provided connected to a second end side (proximal end side) of the oxygen consuming fuel delivery line 345. A flow rate adjustment valve 345a is provided on the oxygen consuming fuel delivery line 345.

The inert gas generation device 340 further includes a control device (computer) 348 connected to the flow rate meter 341c via a flow rate signal cable, connected to the oxygen sensor 341d via an oxygen concentration signal cable, and connected to the flow rate adjustment valve 345a via a control signal cable. The control device 348 controls the degree of opening of the flow rate adjustment valve 345a on the basis of information (flow rate of the exhaust gas 13) obtained from the flow rate meter 341c and information (oxygen concentration of the exhaust gas 13) obtained from the oxygen sensor 341d, to adjust the supply flow rate of the oxygen consuming fuel 37 to be delivered to the exhaust gas extraction line 341.

In the present embodiment as described above, gas extraction means include the exhaust gas extraction line 341, the flow rate adjustment valve 341a, the exhaust fan 341b, and the like. Fuel addition means include the oxygen consuming fuel delivery line 345, the flow rate adjustment valve 345a, the tank 346, and the like. The gas extraction means and the like form heating gas delivery means. Low-oxygen concentration gas supply means include the heating gas delivery means, the fuel addition means, and the like. The control device 348 forms fuel addition quantity control means. The coal pyrolysis device 300 include the coal pyrolysis device main body 110, the exhaust means, the gas extraction means, the low-oxygen concentration gas supply means, the fuel addition control means, and the like. The other means each include similar equipment as the first embodiment described above.

In the coal pyrolysis device 300 according to the present embodiment that includes the inert gas generation device 340 as described above, it is possible to produce the pyrolyzed coal 2 from the dried coal 1 by causing the same central operation as the coal pyrolysis device 100 according to the first embodiment as described previously.

Also, by controlling the flow rate adjustment valve 341a and the extraction fan 341b provided on the exhaust gas extraction line 341, a portion of the exhaust gas 13 that has passed through the desulfurization device 133 is not exhausted outside the system but flows to the exhaust gas extraction line 341 via the exhaust gas exhaust line 118. By controlling the flow rate adjustment valve 345a on the basis of information (flow rate of the exhaust gas 13) obtained from the flow rate meter 341c and information (oxygen concentration of the exhaust gas 13) obtained from the oxygen sensor 341d, a specific quantity of the oxygen consuming fuel 37 is delivered to the first end side (proximal end side) of the inner cylinder 112 of the coal pyrolysis device main body 110 via the exhaust gas extraction line 341. The control device 348 calculates the oxygen flow rate of the exhaust gas 13 on the basis of information (flow rate of the exhaust gas 13) obtained from the flow rate meter 341c and information (oxygen concentration of the exhaust gas 13) obtained from the oxygen sensor 341d, and performs feedback control of the flow rate of the oxygen consuming fuel 37 so that the flow rate of the oxygen consuming fuel 37 is equal to or greater than equivalence of the calculated oxygen flow rate of the exhaust gas 13, in other words, so that the excess oxygen ratio of the oxygen consuming fuel 38 is 1.0 or less.

The inner cylinder 112 is heated by the heating gas 11 delivered to within the outer cylinder 113, so the exhaust gas 13 and the oxygen consuming fuel 37 supplied to within the inner cylinder 112 is heated, the exhaust gas 13 and the oxygen consuming fuel 37 react in priority over the exhaust gas 13 and the dried coal 1, so the oxygen in the exhaust gas 13 is consumed and the oxygen concentration of the exhaust gas 13 is reduced. By reducing the oxygen concentration of the exhaust gas 13, it is used as inert gas within the inner cylinder 112.

In this way, in the present embodiment, the exhaust gas 13 produced by the coal pyrolysis device main body 110 is premixed with the oxygen consuming fuel 37, and by heating the dried coal 1 during pyrolysis using the heat source, the oxygen in the exhaust gas 13 is consumed and its oxygen concentration is reduced, so it can be used as the inert gas to promote the release of the pyrolyzed gas 15 from the dried coal 1.

Therefore, according to the coal pyrolysis device 300 of the present embodiment, by adjusting the quantity of the oxygen consuming fuel 37 to be delivered to the exhaust gas 13 on the basis of information (flow rate of the exhaust gas 13, oxygen concentration of the exhaust gas 13) regarding the exhaust gas 13 flowing through the exhaust gas extraction line 341, so that the oxygen in the exhaust gas 13 within the inner cylinder 112 of the coal pyrolysis device main body 110 is burned by the oxygen consuming fuel 37 and the oxygen concentration is reduced, the inert gas can be obtained. The cost of the flow rate meter 341c, the oxygen sensor 341d, the oxygen consumption fuel supply line 345, the flow rate adjustment valve 345a, and the control device 348 and the operating cost are less compared with those of a PSA, a cryogenic separation device, or the like. Therefore, the inert gas that promotes release of the pyrolyzed gas 15 from the dried coal 1 can be obtained at low cost.

The oxygen consuming fuel 37 reacts with the oxygen in the exhaust gas 13 within the inner cylinder 112 and generates heat, so during pyrolysis of the dried coal 1, the heat of reaction between the oxygen in the exhaust gas 13 and the oxygen consuming fuel 37 can be used as a heat source (pyrolysis heat source) in addition to the heating gas 11. In this way, the quantity of heat supplied from outside the coal pyrolysis device main body 110 as the pyrolysis heat source, in other words, the flow rate of the heating gas 11, can be reduced, and the heat load of the coal pyrolysis device main body 110 can be reduced. As a result, the total length of the outer cylinder 113 (coal pyrolysis device main body 110) can be reduced compared with when the heating gas 11 only is used as the pyrolysis heat source.

Note that in the above, the coal pyrolysis device 100, 200, 300 have been described with a single exhaust fan 118c provided in the exhaust gas exhaust line 118, but a coal pyrolysis device in which a portion of the exhaust gas exhaust line 118 is divided into two systems, and an exhaust fan and a flow rate adjustment valve are provided in each system is also possible.

• 1 Dried coal
• 2 Pyrolyzed coal
• 11 Heating gas
• 12 Heating gas
• 13 Exhaust gas (mixed gas)
• 14 Inert gas (low-oxygen concentration gas)
• 15 Pyrolyzed gas (thermal decomposition gas)
• 16 Supporting fuel (combustion improver)
• 17 Oxygen consuming fuel
• 24 Inert gas (low-oxygen concentration gas)
• 27 Oxygen consuming fuel
• 28 Temperature maintaining fuel
• 29 Temperature maintaining fuel combustion air
• 37 Oxygen consuming fuel
• 110 Coal pyrolysis device main body
• 111 Hopper
• 112 Inner cylinder (main body trunk)
• 113 Outer cylinder (jacket)
• 114 Chute
• 115 Pyrolyzed gas exhaust line
• 116 Combustion furnace
• 117 Heating gas delivery line
• 118 Exhaust gas exhaust line
• 118a Boiler
• 118b Flow rate adjustment valve
• 118c Exhaust fan (outlet blower)
• 119 Heating gas bypass line
• 119a Boiler
• 119b Flow rate adjustment valve
• 121 Exhaust gas recirculation line
• 121a Flow rate adjustment valve
• 130 Exhaust gas processing device
• 131 Denitrification device
• 132 Electric dust collector
• 133 Desulfurization device
• 140 Inert gas generation device
• 141 Exhaust gas extraction line
• 141a Flow rate adjustment valve
• 141b Extraction fan (suction fan)
• 141c Temperature sensor
• 142 Combustion catalyst deoxygenation device (deoxygenation device)
• 143 Heat exchanger
• 144 Exhaust gas bypass line
• 144a Flow rate adjustment valve
• 145 Oxygen consuming fuel delivery line
• 145a Flow rate adjustment valve
• 146 Tank
• 147 Inert gas supply line
• 147a Oxygen sensor
• 240 Inert gas generation device
• 241 Exhaust gas extraction line
• 241a Flow rate adjustment valve
• 241b Extraction fan (suction fan)
• 242 Alternating combustion deoxygenation device (deoxygenation device)
• 242a Combustion chamber
• 242b Device main body
• 242c Burner
• 242d Alternating type heat exchanger
• 242da First heat exchanger main body
• 242db Second heat exchanger main body
• 242e Rotary valve
• 245 Oxygen consuming fuel delivery line
• 245a Flow rate adjustment valve
• 246 Tank
• 247 Inert gas delivery line
• 247a Oxygen sensor
• 340 Inert gas generation device
• 341 Exhaust gas extraction line
• 341a Flow rate adjustment valve
• 341b Extraction fan (suction fan)
• 341c Flow rate meter
• 341d Oxygen sensor
• 345 Oxygen consuming fuel delivery line
• 345a Flow rate adjustment valve
• 346 Tank
• 348 Control device (computer)