JP5575565B2 - Gasifier fuel supply method - Google Patents

Description

  The present invention relates to a gasifier fuel supply method. More specifically, the present invention relates to a fuel supply method suitable for application to a two-stage entrained bed gasifier that produces gas using coal as a raw material.

  As shown in FIG. 3, a two-stage entrained bed gasification furnace that produces gas using coal (pulverized coal) as a raw material includes a combustor 102 that generates thermal energy, and a reductor 103 that performs a gasification reaction using the thermal energy. It consists of. The combustor 102 and the reductor 103 are each provided with one or more combustor burners 104 and reductor burners 105 (only one is shown in the figure) depending on the purpose. Also, a slag discharge port 107 is provided below the combustor burner 104, and the molten slag falls downward. Cooling water 108 for cooling the dropped slag is stored at the bottom. Coal as fuel is introduced into the reductor burner 105 as pulverized coal pulverized to a particle size appropriate for gasification, and pulverized coal is also introduced into the combustor burner 104. Further, air or oxygen is supplied to the combustor burner 104 and is put into the combustor 102 together with the pulverized coal, and high-temperature combustion gas is generated mainly by the combustion of the coal. And in the reductor 103, it mixes with the high temperature combustion gas which generate | occur | produced in the combustor 102, gasification reaction is performed in a high temperature reducing atmosphere field, and combustible gas is produced | generated (patent document 1).

  For example, in the gasification furnace as described above, bituminous coal having a large calorific value is often used as fuel coal (pulverized coal). The gas produced by such a gasification furnace is used, for example, as a fuel gas for a gas turbine operating in a power generation facility or as a raw material gas for a synthesis process.

JP 2009-179790 A

  As described above, the two-stage entrained bed gasifier produces gas using coal as a raw material, but there is also rapid development in emerging countries, and the supply and demand state of fossil fuels, particularly coal, is becoming severe. In the future, in order to secure fuel for power generation, it is necessary to expand the use of sub-bituminous coal and lignite, not only high-quality bituminous coal that has been used in the past, but also high moisture and less calorific value than bituminous coal. .

  However, sub-bituminous coal and lignite have a large amount of volatile components and a small amount of ash, while calorific value is smaller than bituminous coal, and lignite has a moisture content of 60%. There is a problem that it is difficult to use subbituminous coal and lignite by simply replacing it with bituminous coal.

  Then, an object of this invention is to provide the gasifier fuel supply method which can manufacture gas with a two-stage spouted bed type gasifier using subbituminous coal and lignite which cannot be said to be high quality.

In order to achieve this object, the gasifier fuel supply method according to claims 1 and 2 uses a lower combustor for burning the lower fuel to generate heat necessary for the gasification reaction, and the combustion heat of the combustor. In the gasification furnace having a two-stage structure with the upper stage gasifier for gasifying the upper stage fuel, a fuel having a larger calorific value than the upper stage fuel is supplied to the combustor as the lower stage fuel, and the lower stage is supplied with the lower stage. A fuel having a fuel ratio smaller than that of the fuel and less ash is supplied as the upper stage fuel.

Therefore, according to the gasifier fuel supply method of these, the generation of the char in the upper reductor is suppressed, and discharge of molten slag in the gasification reaction and the lower combustor in upper reductor in the lower combustion chamber Sufficient combustion heat is generated. The fuel ratio is a ratio of fixed carbon to volatile matter, and is obtained by dividing fixed carbon by volatile matter.

Further, the invention of claim 1 wherein the fuel for the upper stage is sub-bituminous or lignite, is lower for fuel so that at least bituminous. The invention of claim 2, wherein the fuel for the upper stage is sub-bituminous or lignite, is lower for fuel so that at least petroleum coke. In this case, since sub-bituminous coal and lignite have a small fuel ratio and low ash content, the generation of char in the upper reductor is reliably suppressed, and bituminous coal and petroleum coke generate a large amount of heat so Generation is sufficiently promoted.

Further, the invention according to claim 3 is the gasifier fuel supply method according to claim 1 or 2 , wherein when lignite is used as the upper stage fuel or the lower stage fuel, the lignite is dried and pulverized to be dried in a fine powder state. It further comprises a pulverized coal machine for producing brown coal and a heating unit for supplying a drying gas heated to an appropriate drying temperature to the pulverized coal machine, and steam or IGCC ( Integrated coal Gasification Combined Cycle: Coal gasification combined power generation) The heating section heats the drying gas to an appropriate drying temperature by exchanging heat with steam in the system. In this case, heat generated by gas production in the gasification furnace is effectively utilized in the gas production system.

  According to the gasification furnace fuel supply method of the present invention, it is possible to suppress the generation of char in the upper stage reducer, and in the lower stage combustor, the gasification reaction in the upper stage inductor and the discharge of molten slag in the lower stage combustor. Since sufficient combustion heat can be generated, it is possible to reduce the load on the char recovery device and reduce the maintenance cost of the device itself and the labor and cost of maintenance of the device. In addition, by using sub-bituminous coal or lignite as the upper stage fuel, it is possible to expand the use of coal, which cannot be said to be of high quality, and it is possible to effectively use the fuel.

  Moreover, according to the gasifier fuel supply method of the present invention, heat generated by gas production in the gasifier can be effectively used in the gas production system, and the lignite is dried when lignite is used as fuel. Therefore, it is possible to reduce the cost because no additional fuel is required. Also from this point, the use of coal, which cannot be said to be of high quality, can be expanded, and the fuel can be effectively used.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure explaining an example of embodiment of the gasifier fuel supply method of this invention, and is a schematic block diagram of a two-stage entrained bed type gasifier. It is a figure explaining other embodiment of the gasifier fuel supply method of this invention, and is a schematic block diagram of a two-stage entrained bed type gasifier. It is a schematic block diagram of the two-stage spouted bed type gasifier used conventionally.

  Hereinafter, the configuration of the present invention will be described in detail based on an example of an embodiment shown in the drawings.

  FIG. 1 shows an example of an embodiment of a gasifier fuel supply method of the present invention. In this gasification furnace fuel supply method, the lower stage fuel 5 is combusted to generate heat necessary for the gasification reaction, and the upper stage fuel 4 is gasified using the combustion heat of the combustor 2. The combustor 2 of the two-stage gasification furnace 1 with the upper stage reductor 3 is supplied with a fuel capable of generating combustion heat necessary for the gasification reaction as the lower stage fuel 5, and the lower stage fuel is supplied to the reductor 3. A fuel having a fuel ratio smaller than 5 and less ash is supplied as the upper stage fuel 4.

  As shown in FIG. 1, a gasification furnace 1 to which the gasification furnace fuel supply method of the present invention can be applied is also called a two-stage entrained bed gasification furnace, and communicates with a lower combustor 2 and an upper stage reducer. 3 and a two-stage structure. The gasification furnace 1 burns the lower fuel 5 with the combustor 2 to generate heat necessary for gasification reaction and slag elution, and the upper fuel with the reductor 3 using the combustion heat of the combustor 2. 4 is gasified to produce gas.

  Here, in order for the gasification furnace fuel supply method of the present invention to be applied, if the gasification furnace has a mechanism for supplying different types of fuel to the combustor 2 and the reductor 3, there is a special case. A simple structure and configuration are not necessary. That is, the gasifier fuel supply method of the present invention can be applied to a conventional two-stage entrained bed gasifier.

  The combustor 2 is provided with an ejection nozzle (not shown) for injecting and supplying the lower fuel 5 into the combustor 2, and the upper fuel 4 is combined with a gasifying agent such as air at the lower part of the reductor 3. A jet nozzle (not shown) is provided for jetting into the reductor 3 and supplying it.

  Further, a discharge port for discharging the molten slag 9 is provided at the bottom of the combustor 2, and a line for taking out the generated gas is provided at the top of the reductor 3, and a char recovery device 8 connected to the line is provided. It is done. In order to burn the lower fuel 5, air or oxygen-enriched air is supplied to the combustor 2. However, when the lower fuel 5 has a large amount of water, the combustion heat in the combustor 2 decreases. May increase the concentration of oxygen supplied to the combustor 2.

  The upper-stage fuel 4 is gasified by the reductor 3 to generate gas containing char (reference numerals 6 and 7). A line is provided in the downstream of the gasifier, and the gas (reference numerals 6 and 7) generated by the reductor 3 flows to the char recovery device 8 via the line. Then, the gas (reference numerals 6 and 7) is separated into the product gas 6 and the char 7 by the char recovery device 8 and recovered.

  The product gas 6 separated and recovered by the char recovery device 8 is temporarily stored in a storage facility (not shown) and traded as a product gas or used as a fuel gas for a gas turbine operating in a power generation facility.

  A line is also provided between the char recovery device 8 and the combustor 2, and the char 7 separated and recovered by the char recovery device 8 is re-supplied (in other words, recycled) to the combustor 2 and burned together with the lower-stage fuel 5. To do. In addition, as the char collection device (also called a cyclone) 8, for example, a porous filter or the like conventionally used as a mechanism for collecting char is used.

  Most of the char 7 in the gasification furnace 1 is char generated from the upper stage fuel 4. Further, the ash content of the upper fuel 4 is contained in the char 7, recovered by the char recovery device 8, and recycled together with the char 7. Therefore, it is possible to reduce the load applied to the char recovery device 8 by using a fuel with low ash content as the upper stage fuel 4, thereby reducing the maintenance cost of the char recovery device 8 itself and the labor and cost of maintenance of the device. Can be made.

  The lower fuel 5 burned in the combustor 2 and the ash content in the char 7 become molten slag 9 and are discharged from the discharge port at the bottom of the combustor 2 and fall into the water and recovered.

  The combination of the lower-stage fuel 5 and the upper-stage fuel 4 in the gasifier fuel supply method of the present invention is such that the lower-stage fuel 5 can generate combustion heat necessary for the gasification reaction in the reductor 3 in the combustor 2. At the same time, it is sufficient that the upper stage fuel 4 has a smaller fuel ratio and lower ash content than the lower stage fuel 5, and various combinations are conceivable. In the present invention, not only a single type of fuel is used as the lower stage fuel 5 and the upper stage fuel 4, but the above conditions may be satisfied for a plurality of types of fuel as a whole. Further, in the combustor 2, it is necessary to slag coat the surface of the combustor 2, so a fuel containing a certain amount of ash is used as the lower stage fuel 5.

Specifically, for example, the combinations shown in Table 1 can be considered as combinations satisfying the above conditions. For example, two fuels, bituminous coal and subbituminous coal, are listed in the lower fuel column of the combination B. In this case, the two fuels are mixed in advance or the two fuels are mixed. The two supply lines corresponding to each may be input simultaneously.

  Among the fuels in Table 1, sub-bituminous coal and lignite have less ash content [%] than other fuels, and less char is generated when used as fuel for gasifiers. By using it, the generation of char in the reductor 3 is suppressed.

  Further, subbituminous coal and lignite have a small fuel ratio and a large volatile content [%] as compared with other fuels. Therefore, when used as the upper stage fuel 4, there is little generation of char and the product gas is efficiently generated in the reductor 3. .

  In addition, bituminous coal and petroleum coke (also called pet coke) have a large calorific value [MJ / kg] compared to other fuels, so that they can be used as lower stage fuel 5 for gasification reaction and ash melting in combustor 2. The necessary heat is generated.

  Then, by using subbituminous coal, lignite, and high ash coal together with bituminous coal and petroleum coke having a large calorific value as the lower stage fuel 5, effective utilization of coal that cannot be said to be of high quality is achieved.

  The combination of the lower stage fuel 5 and the upper stage fuel 4 in the gasifier fuel supply method of the present invention is such that the lower stage fuel 5 can generate combustion heat required for the gasification reaction in the reductor 3 in the combustor 2. In addition, the upper fuel 4 may be any fuel that has a smaller fuel ratio and lower ash content than the lower fuel 5, and various combinations are conceivable.

  Here, among the combinations in Table 1, A, B, C, and D, subbituminous coal as the upper stage fuel 4 has a large amount of volatile components and a small amount of ash, and bituminous coal as the lower stage fuel 5 generates heat. Since the amount is large, it is preferable as a combination of the upper fuel 4 and the lower fuel 5. That is, since the upper fuel 4 has a small fuel ratio and low ash content, the generation of char in the reductor 3 is suppressed, and since the volatile content of the upper fuel 4 is large, the generated gas is efficiently generated. Since the calorific value of the industrial fuel 5 is large, combustion heat necessary for gasification reaction and ash melting is sufficiently generated, which is preferable. For combinations B and C, sub-bituminous coal and high ash coal are used as lower stage fuel 5 in addition to bituminous coal. Based on the properties of the coal and the specifications and performance of each gasification furnace 1, sufficient for lower stage combustor 2 is sufficient. The mixing ratio of bituminous coal, subbituminous coal, and high ash coal is determined so as to ensure combustion heat.

  Of the combinations shown in Table 1, D and E have sub-bituminous coal as the upper stage fuel 4 having a large amount of volatile components and a small amount of ash, and petroleum coke as the lower stage fuel 5 has a large calorific value. A combination of the upper fuel 4 and the lower fuel 5 is preferable. That is, since the upper fuel 4 has a small fuel ratio and low ash content, the generation of char in the reductor 3 is suppressed, and since the volatile content of the upper fuel 4 is large, the generated gas is efficiently generated. Since the calorific value of the industrial fuel 5 is large, combustion heat necessary for gasification reaction and ash melting is sufficiently generated, which is preferable. For combination E, when high ash coal is used as the lower stage fuel 5 in addition to petroleum coke, sufficient combustion heat is secured in the lower stage combustor 2 based on the specifications and performance of each gasifier 1. The mixing ratio between petroleum coke and high ash coal is determined.

  Of the combinations shown in Table 1, F, G, H, I, and J include lignite with high volatile content and low ash content as upper fuel 4, and bituminous coal as lower fuel 5 generates heat. Since the amount is large, it is preferable as a combination of the upper fuel 4 and the lower fuel 5. That is, since the fuel for the upper stage 4 has a small fuel ratio and a small amount of ash, the generation of char in the reductor 3 is suppressed. Further, since the calorific value of the lower stage fuel 5 is large, the combustion heat necessary for the gasification reaction and ash melting is increased. This is preferable because it occurs sufficiently. For combinations G, H, and I, sub-bituminous coal, lignite, and high ash coal are used as lower stage fuel 5 in addition to bituminous coal. Based on the properties of the coal and the specifications and performance of each gasifier 1, the lower stage combustor is used. The mixing ratio of bituminous coal, subbituminous coal, lignite, and high ash coal is determined so that sufficient combustion heat in 2 is secured.

  Of the combinations shown in Table 1, J and K are lignite as the upper stage fuel 4 has a large amount of volatile components and a small amount of ash, and petroleum coke as the lower stage fuel 5 has a large calorific value, so the upper stage. This is preferable as a combination of the working fuel 4 and the lower-stage fuel 5. That is, since the fuel for the upper stage 4 has a small fuel ratio and a small amount of ash, the generation of char in the reductor 3 is suppressed. Further, since the calorific value of the lower stage fuel 5 is large, the combustion heat necessary for the gasification reaction and ash melting is increased. This is preferable because it occurs sufficiently. For combination K, when high ash coal is used as the lower stage fuel 5 in addition to petroleum coke, sufficient combustion heat is secured in the lower stage combustor 2 based on the specifications and performance of each gasifier 1. The mixing ratio between petroleum coke and high ash coal is determined.

  Here, when supplying dry lignite in a pulverized state obtained by drying and pulverizing lignite to the combustor 2 or the reductor 3 as the lower fuel 5 or the upper fuel 4, a mechanism for drying and pulverizing the lignite is shown in FIG. As shown, the gas generator 1 may be incorporated into a gas production system. In the example shown in FIG. 2, pulverized dry lignite is supplied to the reductor 3 as the upper stage fuel 4. However, the present invention is not limited to this, and the pulverized dry lignite is supplied to the combustor 2 as the lower stage fuel 5. In this case, the mechanism for drying and pulverizing lignite is the same as that described below.

  Specifically, in the present invention, as a mechanism for drying and pulverizing lignite, gasification of a pulverized coal machine 10 for producing a pulverized dry lignite and a mechanism for heating a drying gas 14 supplied to the pulverized coal machine 10 is gasified. It is incorporated into the gas production system using the furnace 1.

  The pulverized coal machine 10 is an apparatus for producing pulverized dry lignite by drying and pulverizing the raw material in an environment in which the drying gas 14 is introduced using the lignite 12 as a raw material. The drying gas 14 supplied to the pulverized coal machine 10 is heated to a temperature suitable for drying the lignite 14 supplied to the pulverized coal machine 10 (referred to as an appropriate drying temperature) while keeping the oxygen concentration low. The appropriate drying temperature is, for example, about 200 ° C.

  In order to supply the drying gas 14 heated to an appropriate drying temperature to the pulverized coal machine 10, an air heater is provided as the heating unit 11. The air heater 11 is a mixture of air and air 13 having a low oxygen concentration by mixing air and, for example, nitrogen gas in a desired ratio, steam 15 heated through the gasification furnace 1, or part of steam in the IGCC system. Is a heat exchanger for increasing the temperature of the air 13 or the like by exchanging heat with each other. In the example shown in FIG. 2, the steam 15 absorbs heat at the heat exchanging portion 1 a of the gasification furnace 1 and dissipates heat at the heat exchanging portion 11 a of the air heater 11, so that the air 13 is heated to an appropriate drying temperature in the air heater 11. The gas 14 is supplied to the pulverized coal machine 10. The supply source of the steam 15 is not limited to a specific one. Specifically, for example, gasifier furnace wall tube steam may be used (FIG. 2), or a part of the steam in the IGCC system may be used.

  In the mechanism in which the lignite 12 configured as described above is dried, pulverized, and supplied to the gasification furnace 1, air is exchanged by heat exchange with the steam 15 heated by the heat of the gasification furnace 1 or the steam in the IGCC. Since the air heater 11 is provided as a heating unit capable of producing the drying gas 14 by heating the etc. 13 to an appropriate drying temperature, the heat of the gasification furnace 1 generated by the gas production is effectively utilized. That is, the high-temperature drying gas 14 can be obtained by effectively utilizing the heat of gas production in the gasification furnace 1 without burning a separate fuel for gas production.

  According to the gasifier fuel supply method of the present invention configured as described above, the generation of the char 7 in the upper stage reductor 3 can be suppressed, and the gasification reaction in the upper stage reductor 3 can be performed in the lower stage combustor 2. And the combustion heat sufficient for discharging the molten slag 9 in the lower combustor 2 can be generated, so that the load on the char recovery device 8 can be reduced and the maintenance cost of the device 8 itself and the maintenance of the device 8 can be reduced. It is possible to reduce labor and cost.

  In addition, although the above-mentioned form is an example of the suitable form of this invention, it is not limited to this, A various deformation | transformation implementation is possible in the range which does not deviate from the summary of this invention.

DESCRIPTION OF SYMBOLS 1 Gasification furnace 2 Combustor 3 Reductor 4 Upper stage fuel 5 Lower stage fuel 6 Generated gas 7 Char 8 Char recovery device 9 Molten slag

Claims (3)

A gasifier having a two-stage structure comprising a lower combustor that burns lower fuel and generates heat necessary for a gasification reaction, and an upper reductor that gasifies upper fuel using the combustion heat of the combustor. The lower fuel is supplied to the combustor as a fuel having a larger calorific value than the upper fuel, and the lower fuel is supplied with a fuel having a smaller fuel ratio and lower ash content than the lower fuel. supplied as and said a top fuel is sub-bituminous or lignite, features and be Ruga gasification furnace fuel supply method that the lower fuel includes at least bituminous. A gasifier having a two-stage structure comprising a lower combustor that burns lower fuel and generates heat necessary for a gasification reaction, and an upper reductor that gasifies upper fuel using the combustion heat of the combustor. The lower fuel is supplied to the combustor as a fuel having a larger calorific value than the upper fuel, and the lower fuel is supplied with a fuel having a smaller fuel ratio and lower ash content than the lower fuel. supplied as and said a top fuel is sub-bituminous or lignite, features and be Ruga gasification furnace fuel supply method that the lower fuel includes at least petroleum coke. When lignite is used as the upper stage fuel or the lower stage fuel, a pulverized coal machine for drying and pulverizing the lignite to produce a pulverized dry lignite, and a drying gas heated to a suitable drying temperature in the pulverized coal machine A heating unit that supplies the gasification furnace with heat, and heat-exchanged with the steam raised in temperature by absorbing the heat of the gasification furnace or the steam in the IGCC system so that the heating unit brings the drying gas to the proper drying temperature. The gasifier fuel supply method according to claim 1 or 2, wherein heating is performed.

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