JP2019143099A - Powder fuel supply system, gasification furnace equipment, gasification combined power generating unit, and method of controlling powder fuel supply system - Google Patents

Abstract

To provide means to stably supply powder fuel even if a quality state of the powder fuel varies.SOLUTION: A powder fuel supply system comprises: powder transport pipelines 84, 89, and 95 in which mixed gas obtained by mixing powder fuel and nitrogen is transported; burners that are connected to downstream ends of the powder transport pipelines 84, 89, and 95 and supply the mixed gas to an inside of a furnace; dilution nitrogen systems 90 that are connected to the powder transport pipelines 84, 89, and 95 and additionally supply nitrogen; and a control unit that calculates flow rates of the mixed gas flowing in the powder transport pipelines 84, 89, and 95. The control unit, when the flow rates of the mixed gas calculated by mixed gas flow volumes and cross sections of the powder transport pipelines 84, 89, and 95 are less than a predetermined threshold, increases additional inert gas volumes supplied by the additional inert gas supply means 90.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a pulverized fuel supply device for supplying pulverized fuel toward a furnace, a gasification furnace facility, a gasification combined power generation facility, and a control method for the pulverized fuel supply device.

  Conventionally, as a gasifier facility, carbon-containing fuel gasification that generates combustible gas by supplying carbon-containing solid fuel such as coal into the gasifier and partially combusting the carbon-containing solid fuel for gasification Equipment (coal gasification equipment) is known.

  In a coal gasification facility, a fuel supply device that supplies powdered fuel such as pulverized coal or char together with nitrogen (inert gas) into a gasification furnace is known. In order to transport the pulverized fuel, it is necessary to transport the pulverized fuel at a flow rate equal to or higher than a predetermined threshold value so that the pulverized fuel does not settle in the transport pipe and the transport becomes unstable. For this reason, in order to adjust the flow velocity in a conveyance pipe, supplying dilution nitrogen is performed additionally (for example, patent documents 1).

Japanese Patent No. 4070325

  The flow rate of diluted nitrogen supplied into the transfer tube is determined based on a preset relational expression. This relational expression is made on the assumption that the coal supplied to the gasifier is operated with only one coal type.

  However, in the case where the coal supplied to the gasification furnace is multi-coal and the operation is performed while switching the coal type, it is necessary to obtain a plurality of relational expressions corresponding to the coal type in advance. The operator selects and changes the relational expression every time the coal type is switched. However, since there is a time delay after the coal type is switched, it is difficult to grasp the timing for changing the setting. For this reason, there is a problem that not only the labor of the operator increases but also experience is required, and further, the control circuit becomes complicated.

  The control method for the pulverized fuel supply device, the gasification furnace facility, the gasification combined power generation facility, and the pulverized fuel supply device of the present disclosure has been made in view of such circumstances. An object is to stably supply pulverized fuel even if it changes.

  A pulverized fuel supply apparatus according to an aspect of the present disclosure includes a powder carrier in which a mixed gas including a gas in which a pulverized fuel and an accompanying inert gas conveyed along with the pulverized fuel are mixed is conveyed. A pipe, a burner connected to the downstream end of the powder conveying pipe, and supplying a mixed gas toward the gasification furnace for gasifying the pulverized fuel, and connected to the powder conveying pipe and additionally inactive An additional inert gas supply means for additionally supplying gas; and a control unit for calculating a mixed gas flow rate and a mixed gas flow rate flowing in the powder transfer pipe, wherein the control unit includes the mixed gas flow rate and the powder. When the mixed gas flow rate calculated from the cross-sectional area of the body transfer pipe is less than a predetermined threshold, the additional inert gas flow rate supplied from the additional inert gas supply means is increased.

  The accompanying inert gas, which is an accompanying inert gas that flows along with the powder, passes through the powder conveying pipe together with the powder. A mixed gas containing a gas in which the pulverized fuel and the accompanying inert gas are mixed is guided to the burner through the powder conveying pipe and burned in the gasification furnace. When the flow rate of the mixed gas flowing in the powder transfer pipe is calculated, the flow rate of the mixed gas is calculated from the flow rate of the mixed gas and the cross-sectional area of the powder transfer pipe, and the calculated mixed gas flow rate is less than the predetermined threshold In addition, the flow rate of the additional inert gas that is added to the powder conveyance pipe from the additional inert gas supply means to supply the inert gas is increased. Thereby, it is possible to suppress the mixed gas flow rate in the powder transfer pipe from being equal to or higher than a predetermined threshold value, and the powdered fuel settling in the powder transfer pipe to cause a transfer failure. As described above, since the determination is made based on the mixed gas flow velocity, it is not necessary to switch the control to the relational expression obtained in advance according to the type of the pulverized fuel (for example, the coal type), and stable powder conveyance is possible. Can be realized.

  Furthermore, in the pulverized fuel supply apparatus according to an aspect of the present disclosure, the control unit is configured to calculate a filling ratio that is a mass ratio of the pulverized fuel to a mixed gas in the powder conveyance pipe and a flow rate of the pulverized fuel. The filling rate calculation data indicating the relationship is provided in the storage unit, the filling rate is calculated from the powder flow rate using the filling rate calculation data from the set value of the powder flow rate, and the accompanying rate is calculated using the filling rate. The flow rate of the inert gas is calculated, the seal inert gas flow rate is calculated from the set value of the pressure of the gasifier, the powder flow rate, the accompanying inert gas flow rate, the additional inert gas flow rate, or the powder The mixed gas flow rate is calculated from the body flow rate, the accompanying inert gas flow rate, the additional inert gas flow rate, and the seal inert gas flow rate.

  The control unit includes in the storage unit filling rate calculation data indicating the relationship between the filling rate, which is the mass ratio of the pulverized fuel to the mixed gas, and the powder flow rate. Using this filling rate calculation data, the filling rate is calculated from the set powder flow rate, and the accompanying inert gas flow rate in the mixed gas is calculated. Further, a seal inert gas, which is an inert gas having a pressure necessary for sealing a transport pipe that is not used for the gasification furnace, is joined from the middle of the powder transport pipe. The seal inert gas is calculated from the relational expression with respect to the pressure of the supply system. The mixed gas flow rate is obtained from the set powder flow rate and the calculated associated inert gas flow rate, or an added value obtained by adding a seal inert gas flow rate. In this way, the mixed gas flow rate can be obtained at each position where the mixed gas flow rate is evaluated without actually measuring the powder flow rate and the inert gas flow rate supplied to the powder conveyance pipe, so that complicated control is possible. Is no longer necessary.

  Furthermore, in the pulverized fuel supply apparatus according to an aspect of the present disclosure, a powder flow rate measuring unit that measures a powder flow rate that is a mass flow rate of the pulverized fuel flowing in the powder transfer piping, and the powder transfer piping An inert gas flow rate measuring means for measuring an inert gas flow rate supplied to the control unit, wherein the control unit is configured to measure the powder flow rate measured by the powder flow rate measuring means and the inert gas flow rate measuring means. The mixed gas flow rate is calculated from the measured inert gas flow rate.

  The powder flow rate flowing through the powder conveyance pipe is measured by the powder flow rate measuring means. The inert gas flow rate measuring means measures the flow rate of the inert gas supplied to the powder conveyance pipe. The mixed gas flow rate was calculated based on the measured powder flow rate and the measured inert gas flow rate. Thus, since the mixed gas flow velocity can be obtained based on the measured current state quantity, more stable powder conveyance can be realized.

  Furthermore, in the pulverized fuel supply device according to one aspect of the present disclosure, a supply hopper that supplies the pulverized fuel to the powder transfer pipe, and a powder that measures the weight of the pulverized fuel stored in the supply hopper A weight measuring unit, wherein the control unit is a powder having a mass flow rate of the pulverized fuel flowing in the powder conveying pipe based on a change in the weight of the pulverized fuel obtained by the powder weight measuring unit. Estimate body flow.

Based on the weight change of the pulverized fuel stored in the supply hopper, the powder flow rate, which is the mass flow rate of the pulverized fuel flowing through the powder transfer pipe, is estimated. This eliminates the need for a sensor for measuring the powder flow rate in the powder conveyance pipe. For example, it is suitable when the powder conveyance pipe is in a high temperature (for example, 400 ° C. or higher) or low density and a sensor such as a flow meter for measuring the powder flow rate cannot be installed.
When a plurality of supply hoppers are provided and the supply hoppers are switched and used, the powder flow rate obtained from the weight change of the supply hopper before switching may be estimated as the current value.

  Furthermore, in the pulverized fuel supply device according to an aspect of the present disclosure, the control unit mixes each powder conveyance pipe having a different flow path cross-sectional area and / or every powder conveyance pipe branched. The gas flow rate is calculated, and when the smallest mixed gas flow rate is less than a predetermined threshold, the flow rate of the additional inert gas supplied from the additional inert gas supply means is increased.

  If the cross-sectional area of the powder conveyance pipe is different or the powder conveyance pipe is branched, the mixed gas flow velocity will be different in each place. Therefore, the mixed gas flow velocity is calculated for each powder conveying pipe having a different flow path cross-sectional area and / or for each branched powder conveying pipe, and the smallest mixed gas flow velocity is calculated. Based on this, the additional inert gas flow rate was increased.

  A gasification furnace facility according to an aspect of the present disclosure includes the powder fuel supply device according to any one of the above, and a gasification furnace to which the powder fuel is supplied from the powder fuel supply device. .

  A gasification combined power generation facility according to an aspect of the present disclosure includes the gasification furnace facility described above, a gas turbine that is rotationally driven by burning at least a part of the generated gas generated in the gasification furnace facility, A steam turbine that is rotationally driven by steam generated by an exhaust heat recovery boiler that introduces turbine exhaust gas discharged from the gas turbine; and a generator that is rotationally connected to the gas turbine and the steam turbine.

  In the method for controlling a pulverized fuel supply apparatus according to one aspect of the present disclosure, a mixed gas including a gas obtained by mixing a pulverized fuel and an accompanying inert gas conveyed accompanying the pulverized fuel is conveyed. A powder transfer pipe, a burner connected to the downstream end of the powder transfer pipe, and supplying a mixed gas toward the gasification furnace for gasifying the pulverized fuel, and connected to the powder transfer pipe, A method for controlling a pulverized fuel supply apparatus, comprising: an additional inert gas supply means for additionally supplying an additional inert gas; and a controller for calculating a mixed gas flow rate and a mixed gas flow rate flowing in the powder transfer pipe. If the mixed gas flow rate calculated from the mixed gas flow rate and the cross-sectional area of the powder transfer pipe is less than a predetermined threshold, the additional inert gas flow rate supplied from the additional inert gas supply means is increased. Let

  Since the increase in the flow rate of the additional inert gas is determined based on the mixed gas flow rate in the powder conveyance pipe, the pulverized fuel can be stably supplied even if the properties of the pulverized fuel change.

It is the schematic block diagram which showed the coal gasification combined cycle power generation equipment which concerns on 1st Embodiment of this invention. It is the schematic block diagram which showed the gasification furnace installation of FIG. It is the schematic block diagram which showed the system | strain which supplies pulverized coal fuel to a gasifier. It is the graph which showed the filling rate relational expression which is the relationship between a filling rate and pulverized coal fuel. It is the schematic block diagram which showed the supply system | strain of nitrogen supplied to a hopper. It is the schematic block diagram which showed the char supply system | strain which concerns on 2nd Embodiment of this invention. It is the graph which showed the filling rate relational expression which is a relationship between a filling rate and char.

Embodiments according to the present invention will be described below with reference to the drawings.
[First Embodiment]
FIG. 1 shows a schematic configuration of a combined coal gasification combined power generation facility 10 to which a gasification furnace facility 14 is applied.
An IGCC (Integrated Coal Gasification Combined Cycle) 10 uses air as an oxidant mainly, and in the gasifier 14, air that generates combustible gas (product gas) from fuel. The combustion method is adopted. And the coal gasification combined cycle power generation facility 10 refines the produced gas generated in the gasification furnace facility 14 into a fuel gas by the gas purification facility 16, and then supplies it to the gas turbine 17 to generate power. That is, the coal gasification combined power generation facility 10 is an air combustion type (air blowing) power generation facility. As the fuel supplied to the gasifier facility 14, for example, a carbon-containing solid fuel such as coal is used.
In the present embodiment, the positional relationship of each component described using the upper and lower expressions indicates the vertically upper side and the vertically lower side, respectively.

  As shown in FIG. 1, a coal gasification combined power generation facility (gasification combined power generation facility) 10 includes a coal supply facility 11, a gasification furnace facility 14, a char recovery facility 15, a gas purification facility 16, and a gas turbine. 17, a steam turbine 18, a generator 19, and an exhaust heat recovery boiler (HRSG) 20.

  The coal supply facility 11 is supplied with coal, which is a carbon-containing solid fuel, as raw coal, and pulverizes the coal with a coal mill (not shown) to produce finely pulverized coal (powder fuel). To do. The pulverized coal produced in the coal supply facility 11 is pressurized by nitrogen gas as a transfer inert gas supplied from an air separation facility 42 to be described later at the outlet of the coal supply line 11a, toward the gasifier facility 14. Supplied. Inert gas is an inert gas having an oxygen content of about 5% by volume or less, and typical examples include nitrogen gas, carbon dioxide gas, and argon gas. However, the inert gas is not necessarily limited to about 5% by volume or less. .

  The gasifier facility 14 is supplied with the pulverized coal produced in the coal supply facility 11, and the char (unreacted coal and ash: pulverized fuel) recovered in the char recovery facility 15 is returned to the gasifier facility 14. Supplied for use.

  In addition, a compressed air supply line 41 from a gas turbine 17 (compressor 61) is connected to the gasifier furnace 14, and a part of the compressed air compressed by the gas turbine 17 is given a predetermined pressure by a booster 68. The gas can be supplied to the gasifier facility 14 after being boosted. The air separation facility 42 separates and generates nitrogen and oxygen from air in the atmosphere, and the air separation facility 42 and the gasifier facility 14 are connected by a first nitrogen supply line 43. The first nitrogen supply line 43 is connected to a coal supply line 11 a from the coal supply facility 11. In addition, a second nitrogen supply line 45 branched from the first nitrogen supply line 43 is also connected to the gasification furnace facility 14, and a char return line 46 from the char recovery facility 15 is connected to the second nitrogen supply line 45. It is connected. Further, the air separation facility 42 is connected to the compressed air supply line 41 by an oxygen supply line 47. Then, the nitrogen separated by the air separation facility 42 is used as coal or char transport gas by flowing through the first nitrogen supply line 43 and the second nitrogen supply line 45. The oxygen separated by the air separation facility 42 is used as an oxidant in the gasifier facility 14 by flowing through the oxygen supply line 47 and the compressed air supply line 41.

  The gasifier furnace 14 includes, for example, a two-stage spouted bed gasifier 101 (see FIG. 2). The gasification furnace facility 14 is gasified by partially burning coal (pulverized coal) and char supplied therein with an oxidant (air, oxygen) to produce a product gas. The gasifier facility 14 is provided with a foreign matter removing facility 48 for removing foreign matter (slag) mixed in the pulverized coal. The gasification furnace facility 14 is connected to a gas generation line 49 for supplying a generated gas toward the char recovery facility 15 so that the generated gas containing char can be discharged. In this case, as shown in FIG. 2, a syngas cooler 102 (gas cooler) may be provided in the gas generation line 49 to cool the generated gas to a predetermined temperature before supplying it to the char recovery facility 15.

  The char collection facility 15 includes a dust collection facility 51 and a supply hopper 52. In this case, the dust collection facility 51 is configured by one or a plurality of cyclones or porous filters, and can separate char contained in the product gas generated by the gasification furnace facility 14. The product gas from which the char has been separated is sent to the gas purification facility 16 through the gas discharge line 53. The supply hopper 52 stores the char separated from the generated gas by the dust collection equipment 51. A bin may be disposed between the dust collection facility 51 and the supply hopper 52, and a plurality of supply hoppers 52 may be connected to the bin. A char return line 46 from the supply hopper 52 is connected to the second nitrogen supply line 45.

The gas purification facility 16 performs gas purification by removing impurities such as sulfur compounds and nitrogen compounds from the product gas from which the char has been separated by the char recovery facility 15. The gas purification facility 16 then refines the produced gas to produce fuel gas, and supplies this to the gas turbine 17. Since the product gas from which the char has been separated still contains sulfur (H ₂ S, etc.), the gas purification facility 16 removes and recovers the sulfur with an amine absorption liquid and effectively uses it. To do.

  The gas turbine 17 includes a compressor 61, a combustor 62, and a turbine 63, and the compressor 61 and the turbine 63 are connected by a rotating shaft 64. A compressed air supply line 65 from the compressor 61 is connected to the combustor 62, a fuel gas supply line 66 from the gas purification facility 16 is connected to the combustor 62, and a combustion gas supply line 67 extending toward the turbine 63 is connected. Is connected. In addition, the gas turbine 17 is provided with a compressed air supply line 41 extending from the compressor 61 to the gasifier facility 14, and a booster 68 is provided in the middle. Accordingly, the combustor 62 generates combustion gas by mixing and combusting a part of the compressed air supplied from the compressor 61 and at least a part of the fuel gas supplied from the gas purification facility 16. The generated combustion gas is supplied to the turbine 63. The turbine 63 rotates the generator 19 by rotating the rotating shaft 64 with the supplied combustion gas.

  The steam turbine 18 includes a turbine 69 that is connected to a rotating shaft 64 of the gas turbine 17, and the generator 19 is connected to a base end portion of the rotating shaft 64. The exhaust heat recovery boiler 20 is connected to an exhaust gas line 70 from the gas turbine 17 (the turbine 63), and heat exchange is performed between the feed water to the exhaust heat recovery boiler 20 and the exhaust gas of the turbine 63, thereby generating steam. Is generated. The exhaust heat recovery boiler 20 is provided with a steam supply line 71 and a steam recovery line 72 between the steam 69 and the turbine 69 of the steam turbine 18, and a condenser 73 is provided in the steam recovery line 72. Further, the steam generated in the exhaust heat recovery boiler 20 may include steam generated by heat exchange with the generated gas in the syngas cooler 102 of the gasification furnace 101. Therefore, in the steam turbine 18, the turbine 69 is rotationally driven by the steam supplied from the exhaust heat recovery boiler 20, and the generator 19 is rotationally driven by rotating the rotating shaft 64.

  A gas purification facility 74 is provided from the outlet of the exhaust heat recovery boiler 20 to the chimney 75.

Next, the operation of the coal gasification combined power generation facility 10 will be described.
In the coal gasification combined power generation facility 10, when raw coal (coal) is supplied to the coal supply facility 11, the coal is pulverized into fine particles by being pulverized into fine particles in the coal supply facility 11. The pulverized coal produced in the coal supply facility 11 is supplied to the gasifier facility 14 through the first nitrogen supply line 43 by nitrogen supplied from the air separation facility 42. Further, the char recovered by the char recovery facility 15 described later is supplied to the gasifier facility 14 through the second nitrogen supply line 45 by the nitrogen supplied from the air separation facility 42. Further, compressed air extracted from a gas turbine 17 described later is boosted by a booster 68 and then supplied to the gasifier facility 14 through the compressed air supply line 41 together with oxygen supplied from the air separation facility 42.

  In the gasifier furnace 14, the supplied pulverized coal and char are combusted by compressed air (oxygen), and the pulverized coal and char are gasified to generate product gas. The generated gas is discharged from the gasifier facility 14 through the gas generation line 49 and sent to the char recovery facility 15.

  In the char recovery facility 15, the product gas is first supplied to the dust collection facility 51, whereby fine char contained in the product gas is separated. The product gas from which the char has been separated is sent to the gas purification facility 16 through the gas discharge line 53. On the other hand, the fine char separated from the product gas is deposited in the supply hopper 52, returned to the gasifier facility 14 through the char return line 46, and recycled.

  The product gas from which the char has been separated by the char recovery facility 15 is subjected to gas purification by removing impurities such as sulfur compounds and nitrogen compounds in the gas purification facility 16 to produce fuel gas. The compressor 61 generates compressed air and supplies it to the combustor 62. The combustor 62 mixes the compressed air supplied from the compressor 61 and the fuel gas supplied from the gas refining facility 16 and combusts to generate combustion gas. By rotating the turbine 63 with this combustion gas, the compressor 61 and the generator 19 are rotationally driven via the rotating shaft 64. In this way, the gas turbine 17 can generate power.

The exhaust heat recovery boiler 20 generates steam by exchanging heat between the exhaust gas discharged from the turbine 63 in the gas turbine 17 and the feed water to the exhaust heat recovery boiler 20, and the generated steam is used as the steam turbine 18. To supply. In the steam turbine 18, the turbine 69 is rotationally driven by the steam supplied from the exhaust heat recovery boiler 20, whereby the generator 19 can be rotationally driven via the rotating shaft 64 to generate electric power.
Note that the gas turbine 17 and the steam turbine 18 may be configured to rotationally drive a plurality of generators as separate shafts instead of the configuration in which the single generator 19 is rotationally driven as the same shaft.

  Thereafter, in the gas purification equipment 74, harmful substances in the exhaust gas discharged from the exhaust heat recovery boiler 20 are removed, and the purified exhaust gas is released from the chimney 75 to the atmosphere.

  Next, with reference to FIG.1 and FIG.2, the gasification furnace equipment 14 in the coal gasification combined cycle power generation equipment 10 mentioned above is demonstrated in detail.

  As shown in FIG. 2, the gasification furnace facility 14 includes a gasification furnace 101 and a syngas cooler 102.

  The gasification furnace 101 is formed so as to extend in the vertical direction. Pulverized coal and oxygen are supplied to the lower side in the vertical direction, and the product gas gasified by partial combustion is directed from the lower side in the vertical direction toward the upper side. Are in circulation. The gasification furnace 101 includes a pressure vessel 110 and a gasification furnace wall 111 provided inside the pressure vessel 110. In the gasification furnace 101, an annulus portion 115 is formed in a space between the pressure vessel 110 and the gasification furnace wall 111. Further, the gasification furnace 101 has a combustor unit 116, a diffuser unit 117, and a reductor unit 118 in order from the lower side in the vertical direction (that is, the upstream side in the flow direction of the product gas) in the space inside the gasification furnace wall 111. Is forming.

  The pressure vessel 110 is formed in a cylindrical shape having a hollow space inside, a gas discharge port 121 is formed at the upper end portion, and a slag hopper 122 is formed at the lower end portion (bottom portion). The gasification furnace wall 111 is formed in a cylindrical shape whose inside is a hollow space, and the wall surface thereof is provided to face the inner surface of the pressure vessel 110. In this embodiment, the pressure vessel 110 has a cylindrical shape, and the diffuser portion 117 of the gasification furnace wall 111 is also formed in a cylindrical shape. The gasification furnace wall 111 is connected to the inner surface of the pressure vessel 110 by a support member (not shown).

  The gasification furnace wall 111 separates the interior of the pressure vessel 110 into an internal space 154 and an external space 156. The gasification furnace wall 111 has a cross-sectional shape that changes in a diffuser portion 117 between the combustor portion 116 and the reductor portion 118. The upper end portion of the gasification furnace wall 111 on the vertically upper side is connected to the gas discharge port 121 of the pressure vessel 110, and the lower end portion on the vertically lower side is provided with a gap from the bottom portion of the pressure vessel 110. ing. The slag hopper 122 formed at the bottom of the pressure vessel 110 stores stored water, and the lower end of the gasification furnace wall 111 is immersed in the stored water, thereby sealing the inside and outside of the gasification furnace wall 111. It has stopped. Burners 126 and 127 are inserted into the gasification furnace wall 111, and the syngas cooler 102 is disposed in the internal space 154. The structure of the gasification furnace wall 111 will be described later.

  The annulus 115 is a space formed inside the pressure vessel 110 and outside the gasification furnace wall 111, that is, an external space 156. Nitrogen, which is an inert gas separated by the air separation equipment 42, is not shown in the figure. Supplied through the supply line. For this reason, the annulus portion 115 becomes a space filled with nitrogen. An in-furnace pressure equalizing tube (not shown) for equalizing the pressure in the gasification furnace 101 is provided in the vicinity of the upper portion of the annulus portion 115 in the vertical direction. The pressure equalizing pipe in the furnace is provided so as to communicate between the inside and outside of the gasification furnace wall 111, and the pressure between the inside (combustor part 116, diffuser part 117 and reductor part 118) and outside (annulus part 115) of the gasification furnace wall 111. The pressure is almost equalized so that the difference is within a predetermined pressure.

  The combustor unit 116 is a space for partially burning pulverized coal, char, and air, and a combustion apparatus including a plurality of burners 126 is disposed on the gasification furnace wall 111 in the combustor unit 116. The high-temperature combustion gas obtained by burning part of the pulverized coal and char in the combustor unit 116 passes through the diffuser unit 117 and flows into the reductor unit 118.

  The reductor unit 118 is maintained at a high temperature necessary for the gasification reaction, and supplies the pulverized coal to the combustion gas from the combustor unit 116 to partially burn the pulverized coal (for example, carbon monoxide, hydrogen, lower hydrocarbons, etc.). And a gasification furnace wall 111 in the reductor unit 118 is provided with a combustion device composed of a plurality of burners 127.

  The syngas cooler 102 is provided inside the gasification furnace wall 111 and is provided above the burner 127 of the reductor unit 118 in the vertical direction. The syngas cooler 102 is a heat exchanger, and in order from the lower side in the vertical direction of the gasification furnace wall 111 (upstream side in the flow direction of the product gas), an evaporator 131, a superheater (superheater) 132, A charcoal unit (economizer) 134 is arranged. These syngas coolers 102 cool the generated gas by exchanging heat with the generated gas generated in the reductor unit 118. Further, the quantity of the evaporator (evaporator) 131, the superheater (superheater) 132, and the economizer 134 is not limited.

The gasifier facility 14 described above operates as follows.
In the gasification furnace 101 of the gasification furnace facility 14, nitrogen and pulverized coal are supplied and ignited by the burner 127 of the reductor unit 118, and pulverized coal and char and compressed air (oxygen) are generated by the burner 126 of the combustor unit 116. It is turned on and ignited. Then, in the combustor unit 116, high-temperature combustion gas is generated by the combustion of pulverized coal and char. Further, in the combustor section 116, molten slag is generated in the high-temperature gas by the combustion of pulverized coal and char, and this molten slag adheres to the gasification furnace wall 111 and falls to the furnace bottom, and finally in the slag hopper 122. Discharged into the water storage. Then, the high-temperature combustion gas generated in the combustor unit 116 rises to the reductor unit 118 through the diffuser unit 117. In this reductor unit 118, the high temperature state necessary for the gasification reaction is maintained, the pulverized coal is mixed with the high temperature combustion gas, the pulverized coal is partially burned in a high temperature reducing atmosphere, and the gasification reaction is performed. Is generated. The gasified product gas flows from the lower side to the upper side in the vertical direction.

[Pulverized coal supply system]
Next, pulverized coal and nitrogen are supplied from a pulverized coal supply hopper storing pulverized coal to a pulverized coal burner to which pulverized coal (powder) is supplied among a plurality of burners 126 and 127 (see FIG. 2). A pulverized coal supply system (pulverized fuel supply device) for supplying a mixed gas of (inert gas) will be described.

  FIG. 3 shows a schematic configuration of the pulverized coal supply system 1A. The pulverized coal supply system 1 </ b> A is provided so as to supply pulverized coal from the pulverized coal supply hopper 80 (hereinafter, simply referred to as “hopper 80”) to the gasifier facility 14. A plurality of hoppers 80 (for example, three in FIG. 1) are provided. Each hopper 80 is switched so that pulverized coal is discharged one by one during use. Therefore, when one hopper 80 is discharging pulverized coal, the other hoppers 80 are in a standby state for discharge. To the hopper 80, an upper pressure adjustment nitrogen system 81, a lower pressure adjustment nitrogen system 82, and a fluidized nitrogen system 83 are connected.

  The upper pressure adjusting nitrogen system 81 is configured to supply nitrogen from the upper part of the hopper 80, and the pressure difference from the pressure in the pressure vessel 110 (see FIG. 2) of the gasifier facility 14 during discharge of the hopper 80. Is to keep the constant. The nitrogen flow rate of the upper pressure adjustment nitrogen system 81 is controlled by the control unit 30.

  The lower pressure adjusting nitrogen system 82 applies pressure to the hopper 80 for sending pulverized coal to a discharge port at the bottom of the hopper 80. The nitrogen flow rate of the lower pressure adjusting nitrogen system 82 is controlled by the control unit 30.

The fluidized nitrogen system 83 fluidizes the pulverized coal around the entrance of the transport pipe 84. The nitrogen flow rate of the fluidized nitrogen system 83 is controlled by the control unit 30.
The nitrogen flow rate charged into the hopper is the sum of the upper pressure adjustment nitrogen system 81, the lower pressure adjustment nitrogen system 82, and the fluidized nitrogen system 83 and converted in terms of nitrogen specific gravity. The adjoining nitrogen volume flow rate described later is obtained by converting a nitrogen flow rate obtained by subtracting a nitrogen flow rate used for maintaining the pressure of the hopper from a nitrogen flow rate supplied to the hopper into a nitrogen specific gravity.

  A transport pipe (powder transport pipe) 84 is connected to each hopper 80. A transport pipe seal nitrogen system 85 is connected to each transport pipe 84 on the upstream side before the merger 86. The transfer pipe seal nitrogen system 85 pressurizes the pressure in the transfer pipe 84 corresponding to the unused hopper 80 to a predetermined value or more. Thereby, even if the unused hopper 80 is released to the atmosphere, the gasifier equipment 14 is sealed.

  The downstream ends of the transport pipes 84 are connected to the merger 86 so as to merge. The merger 86 is connected to a distributor 88 via a merged conveyance pipe 87. A plurality (for example, two in FIG. 1) of distribution pipes (powder transfer pipes) 89 are connected to the distributor 88 in parallel.

  In each distribution pipe 89, a diluted nitrogen system (additional inert gas supply means) 90, a flow meter (powder flow rate measurement means) 91, a γ-ray density meter (powder density measurement means) 92, fine powder, in order from the upstream side A charcoal flow rate adjustment valve 93 is provided. The γ-ray density meter 92 only needs to be able to measure the density of pulverized coal in the mixed gas, and is not limited to γ-rays.

  The diluted nitrogen system 90 additionally supplies diluted nitrogen, which is nitrogen for dilution, into the distribution pipe 89 to adjust the flow rate in the pipe of the mixed gas of pulverized coal and nitrogen. The diluted nitrogen flow rate (additional inert gas flow rate) obtained by adding the diluted nitrogen of the diluted nitrogen system 90 is set so that the in-pipe flow rate of the mixed gas is equal to or higher than a predetermined threshold value. The threshold value of the flow velocity in the tube is set, for example, from a range of 1.5 m / s or more and 8 m / s or less, and is adjusted by the diluted nitrogen flow rate. The diluted nitrogen flow rate of the diluted nitrogen system 90 is controlled by the control unit 30. If the flow velocity in the pipe is less than 1.5 m / s, the pulverized coal settles in the pipe and the conveyance becomes unstable. Moreover, if the flow velocity in the tube exceeds 8 m / s, the overall flow velocity becomes too fast, which causes an increase in pressure loss of the diluted nitrogen system 90 and acceleration of pipe wear.

  The flow meter 91 measures the volume flow rate of the mixed gas. The measurement output of the flow meter 91 is transmitted to the control unit 30. The γ-ray density meter 92 measures the density of pulverized coal in the mixed gas. The measurement output of the γ-ray density meter 92 is transmitted to the control unit 30. The mass flow rate of the mixed gas can be calculated by the control unit 30 based on the volume flow rate obtained by the flow meter 91 and the density obtained by the γ-ray density meter 92.

  The opening degree of the pulverized coal flow rate adjustment valve 93 is controlled by the control unit 30 and adjusts the flow rate of the mixed gas flowing in the distribution pipe 89.

  The downstream end of each distribution pipe 89 is connected to the burner distributor 94. A plurality of (for example, four in FIG. 3) branch pipes (powder transport pipes) 95 are connected to the burner distributor 94 in parallel. Each branch pipe 95 is provided with a γ-ray density meter 96. Downstream of each branch pipe 95, burners 126 and 127 (see FIG. 2) are connected, and the mixed gas is guided into the gasification furnace wall 111 (see FIG. 2) of the gasification furnace facility. . The γ-ray density meter 96 only needs to be able to measure the density of pulverized coal in the mixed gas, and is not limited to γ-rays.

  The control unit 30 includes, for example, a central processing unit (CPU), a random access memory (RAM), a read only memory (ROM), and a computer-readable storage medium. A series of processes for realizing various functions is stored in a storage medium or the like in the form of a program as an example, and the CPU reads the program into a RAM or the like to execute information processing / arithmetic processing. As a result, various functions are realized. The program is preinstalled in a ROM or other storage medium, provided in a state stored in a computer-readable storage medium, or distributed via wired or wireless communication means. Etc. may be applied. The computer-readable storage medium is a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like.

[Calculation of mixed gas flow velocity]
Next, calculation of the flow velocity of the mixed gas flowing in the piping of the pulverized coal supply system 1A having the above configuration will be described. In the present embodiment, the mixed gas flow rate is not directly measured, but is calculated using a predetermined set value.

  The mixed gas flow velocity is calculated for each pipe having a different flow path cross-sectional area and / or for each branched pipe. For example, as shown in FIG. 3, the first position M1 of the transport pipe 84, the second position M2 downstream of the pulverized coal flow rate adjustment valve 93 of the distribution pipe 89, and the downstream side of the γ-ray density meter 96 of the branch pipe 95. The mixed gas flow velocity at the third position M3 is calculated.

  The pulverized coal flow rate (solid volume flow rate) is obtained by dividing the set value (mass flow rate) of the pulverized coal flow rate given to the control unit 30 by the true specific gravity of the pulverized coal. Here, the pulverized coal true specific gravity is the specific gravity of the pulverized coal itself (solid), unlike the pulverized coal bulk specific gravity.

  The accompanying nitrogen volume flow rate, which is the accompanying nitrogen flowing along with the pulverized coal, is calculated from the nitrogen flow rate obtained by adding the upper pressure adjusting nitrogen system 81, the lower pressure adjusting nitrogen system 82, and the fluidized nitrogen system 83 of the hopper 80. The accompanying nitrogen flow rate (accompanied inert gas flow rate) obtained by subtracting the nitrogen flow rate used for holding is converted into the nitrogen specific gravity. The accompanying nitrogen flow rate is set by the control unit 30 using the pulverized coal flow rate. The adjoining nitrogen flow rate may be set using the filling rate shown below or calculated from measured values as described later.

  The adjoining nitrogen volume flow rate is obtained from a filling rate relational expression (filling rate calculation data) showing a relationship between a filling rate which is a mass ratio of pulverized coal to the mixed gas and a pulverized coal flow rate. FIG. 4 shows a filling rate relational expression. This filling rate relational expression is stored in the storage unit of the control unit 30. In the figure, the horizontal axis represents the pulverized coal flow rate ratio, and the vertical axis represents the filling rate. The pulverized coal flow rate ratio is made dimensionless by dividing by the reference pulverized coal flow rate. As a result of intensive studies, the present inventors have found that there is a certain relationship between the pulverized coal flow rate (or the pulverized coal flow rate ratio calculated from the pulverized coal flow rate) and the filling rate. If this filling rate relational expression is obtained, the filling rate can be obtained from the pulverized coal flow rate ratio calculated from the pulverized coal flow rate, and as a result, the accompanying nitrogen volume flow rate can be obtained from the ratio of nitrogen flowing in the pipe.

  The flow rate of the seal nitrogen supplied to the conveying pipe 84 of the hopper 80 that is not used can be obtained by using the set value of the gasifier pressure given to the control unit 30. For example, since the pressure required for sealing is determined according to the gasifier pressure, a function for the gasifier pressure is set and stored in the storage unit of the control unit 30, and given to the control unit 30 according to this function. A seal nitrogen flow rate (seal inert gas flow rate), which is a flow rate of sealing nitrogen, is calculated from the set value of the gasifier pressure.

  By adding the pulverized coal flow rate (solid volume flow rate) and the accompanying nitrogen volume flow rate obtained as described above, the volume flow rate of the mixed gas flowing through the pipe of the transfer pipe 84 is obtained. For example, the flow of the pipe at the position M1 By dividing by the road cross-sectional area, the mixed gas flow velocity at the position M1 is obtained. Further, the distribution pipe 89 on the downstream side of the confluencer 86 is summed by adding the volume flow rate of the mixed gas (pulverized coal flow rate (solid volume flow rate) and associated nitrogen flow rate), the seal nitrogen flow rate, and the diluted nitrogen flow rate. A volumetric flow rate of the mixed gas flowing in the pipe is obtained. The mixed gas flow rate is obtained by dividing the volume flow rate of the mixed gas by the channel cross-sectional area of each pipe. For example, the mixed gas flow rates at the positions M2 and M3 are obtained.

[Control of dilute nitrogen flow rate]
As described above, for example, when the mixed gas flow velocity at each position M1, M2, M3 is obtained, the control unit 30 sets the smallest minimum mixed gas flow velocity among the preselected positions such as each position M1, M2, M3, for example. It is determined whether or not this minimum mixed gas flow rate is greater than a predetermined threshold value (in this embodiment, for example, selected from a range of 1.5 m / s to 8 m / s). When the minimum mixed gas flow rate is equal to or higher than the predetermined threshold, the flow rate of the diluted nitrogen supplied from the diluted nitrogen system 90 is kept constant without changing. When the minimum mixed gas flow rate becomes less than the predetermined threshold value, the diluted nitrogen flow rate is increased by a predetermined amount, and when the threshold value is exceeded, the diluted nitrogen flow rate is maintained. Further, an upper limit value obtained by adding a predetermined amount from the threshold value may be provided, and the diluted nitrogen flow rate may be decreased when the upper limit value is exceeded (for example, when the mixed gas flow rate exceeds 8 m / s).

According to this embodiment, there exist the following effects.
When the mixed gas flow rate calculated by the control unit 30 is less than a predetermined threshold, the flow rate of diluted nitrogen supplied from the diluted nitrogen system 90 to the distribution pipe 89 is increased. As a result, the mixed gas flow rate becomes equal to or higher than a predetermined threshold, and it is possible to suppress the occurrence of poor conveyance due to pulverized coal settling in the piping. Thus, since it determined based on mixed gas flow velocity, it is not necessary to switch control according to the coal type of pulverized coal, and stable pulverized coal conveyance (powder conveyance) is realizable.

  The control unit 30 includes a storage unit of the control unit 30 that has a filling rate relational expression showing a relationship between a filling rate that is a mass ratio of the pulverized coal to the mixed gas and a pulverized coal flow rate. Using this filling rate relational expression, the filling rate is calculated from the pulverized coal flow rate ratio calculated from the pulverized coal flow rate, and the adjoining nitrogen flow rate in the mixed gas is calculated. Further, a function indicating the relationship between the gasification furnace pressure and the seal nitrogen flow rate is set and provided in the storage unit of the control unit 30. According to this function, the seal nitrogen flow rate is calculated from the set value of the gasifier pressure given to the control unit 30. Then, the mixed gas flow rate is obtained from the added value of the accompanying nitrogen flow rate, pulverized coal flow rate (set value), seal nitrogen flow rate, and diluted nitrogen flow rate. Thus, the mixed gas flow rate can be obtained without measuring the pulverized coal flow rate or the nitrogen flow rate at each position where the mixed gas flow rate is evaluated, and complicated control becomes unnecessary.

  If the cross-sectional areas of the pipes are different or the pipes are branched, the mixed gas flow velocity will be different at each location. Therefore, the mixed gas flow rate is calculated for each pipe having a different channel cross-sectional area and / or for each branched pipe, and the dilute nitrogen flow rate is increased based on the smallest mixed gas flow rate to determine the mixed gas flow rate. Therefore, the pulverized coal does not settle down in the pipe and the conveyance becomes unstable, and the pulverized coal fuel can be stably stabilized even if the properties of the pulverized coal fuel (powder fuel) change. Can be supplied.

[Modification of First Embodiment]
In calculating the filling rate for setting the adjoining nitrogen flow rate that flows along with the pulverized coal, the filling rate is used without using the relational expression of the filling rate set between the pulverized coal flow rate ratio and the filling rate described above. Is calculated from the measured value and set. That is, the filling rate may be calculated from the measured value, and the mixed gas flow rate may be calculated.
A calculation example in this modification will be described below. FIG. 5 shows a nitrogen system supplied to the hopper 80 shown in FIG. Nitrogen of a hopper input nitrogen flow rate (measured value) Wu (kg / h) is supplied to the hopper 80 as a total nitrogen flow rate of the upper pressure adjustment nitrogen system 81, the lower pressure adjustment nitrogen system 82, and the fluidized nitrogen system 83. The hopper input nitrogen flow rate (measured value) Wu is a flow meter (inert gas flow measuring means) 81a provided in the upper pressure adjustment nitrogen system 81 and a flow meter (inert gas) provided in the lower pressure adjustment nitrogen system 82. It can be obtained in total from the flow rate measured by the flow rate measurement means) 82a and the flow rate measured by the flow meter (inert gas flow rate measurement means) 83a provided in the fluidized nitrogen system 83.

Nitrogen at a transfer pipe seal nitrogen flow rate Ws (kg / h) is supplied from the transfer pipe seal nitrogen system 85 to the transfer pipe 84. The transfer pipe seal nitrogen flow rate Ws can be calculated from a calculated value from the pressure around the resistor 32.
The transport pipe seal nitrogen flow rate Ws does not flow through the connection portion between the transport pipe 84 and the hopper 80 that transports pulverized coal from the hopper 80. That is, the connection position with the transport pipe seal nitrogen system 85 is in front of the upstream side of the merger 86 (see FIG. 3), and the transport pipe seal is connected to the connection position between the transport pipe 84 and the transport pipe seal nitrogen system 85. The nitrogen flow rate Wt in the transport pipe is calculated using the filling rate when nitrogen is not supplied. Therefore, below, it calculates with the filling rate which does not include the conveyance pipe seal nitrogen flow rate Ws.

In the calculation of the nitrogen flow rate Wt and the filling rate in the transfer pipe flowing in the transfer pipe 84, the calculation is performed in consideration of the nitrogen flow rate Wg (kg / h) in the pulverized coal particles contained in the pulverized coal. Therefore, the nitrogen flow rate Wg in the pulverized coal particles is added to the nitrogen flow rate Wt in the transport pipe. The nitrogen flow rate Wg in the pulverized coal particles is expressed by the following formula.
Wg = Wp / (γt−γp) × γn
Here, Wp is the pulverized coal flow rate (measured value), γt is the pulverized coal true specific gravity, γp is the pulverized coal bulk specific gravity, and γn is the nitrogen density. The pulverized coal flow rate (measured value) Wp can be obtained from the flow meter 91 and the γ-ray density meter 92 shown in FIG.
γn (nitrogen density) is as follows.
γn = 1.25 × (P + 0.101325) /0.101325×273/ (T + 273)
Here, P (MPa) is the pressure in the hopper 80, and T (° C.) is the temperature in the hopper 80.
The term of Wp / (γt−γp) in the above formula representing Wg corresponds to the space volume within the pulverized coal particles.

When a predetermined amount of pulverized coal is consumed in the hopper 80 as indicated by an arrow A1 in FIG. 5 among the hopper input nitrogen flow rate Wu input to the hopper 80 during conveyance, the volume flow rate corresponding to this consumption amount The nitrogen corresponding to is replaced in the hopper 80. The in-hopper nitrogen replacement flow rate Wc, which is this replacement amount, is subtracted from the hopper input nitrogen flow rate Wu. The hopper nitrogen replacement flow rate Wc is expressed by the following equation.
Wc = (Wp / γp) × γn

According to the calculation example in the present modification, the nitrogen flow rate Wt in the transport pipe is expressed as follows under the above assumption.
Wt = Wu−Wc + Wg (kg / h)

Therefore, the filling rate in the transport pipe according to the calculation example in the present modification is expressed by the following formula using the nitrogen flow rate Wt in the transport pipe.
[Filling rate] = (Wp / γp) / (Wp / γp + Wt / γn)
The solid-gas ratio is represented by Wp / Wt, and the volume ratio is represented by (Wp / γp) / (Wt / γn).
The volume of the mixed gas flowing through the pipe of the transport pipe 84 by adding the volume flow of pulverized coal (solid volume flow, Wp / γt) and the nitrogen volume flow of the transport pipe (volume flow of inert gas, Wt / γn). The flow rate is obtained, and the mixed gas flow velocity at the position M1 is obtained, for example, by dividing by the flow passage cross-sectional area of the pipe at the position M1. That is, the mixed gas flow rate can be obtained using the pulverized coal flow rate (measured value) Wp and the filling rate.

According to this modification, the following operational effects can be obtained.
The pulverized coal flow rate (measured value) Wp obtained using the flow meter 91 and the γ-ray density meter 92, the nitrogen flow rate (measured value) supplied into the hopper 80 obtained by the flow meters 81a, 82a, 83a, and From the nitrogen replacement flow rate Wc in the hopper calculated from the pressure change of the hopper 80, the nitrogen flow rate Wt in the transfer tube flowing through the transfer tube 84 is obtained, and the volume flow rate of the mixed gas obtained by adding the respective volume flow rates obtained from these is calculated. be able to. Since the volumetric flow rate of the mixed gas flowing through the inside of the transfer pipe 84 is obtained, the mixed gas flow velocity at the position M1 is obtained by dividing by the flow path cross-sectional area of the pipe at the position M1, for example. Thus, since the mixed gas flow velocity can be obtained based on the measured current state quantity, more stable powder conveyance can be realized.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. In the present embodiment, the char property is changed in accordance with the change in the property of the pulverized coal fuel (powder fuel) and the char is stably supplied, and the pulverized coal supply system through which the pulverized coal flows is described. In one embodiment, the present invention relates to a char supply system through which char flows. Further, since the flow meter 91 and the γ-ray density meter 92 provided in the distribution pipe 89 (FIG. 3) of the pulverized coal supply system 1A of the first embodiment are not provided, the method for obtaining the char flow rate is different. However, since it is used in the same coal gasification combined power generation facility 10 and is common in terms of conveying powder, description of common parts will be omitted.

  FIG. 6 shows a char supply system (powder fuel supply) for supplying char from a char supply hopper 80 ′ storing char to a char burner to which char is supplied among a plurality of burners 127 (see FIG. 2). Device) 1B is shown.

  The char supply system 1 </ b> B is provided so as to supply char from the char supply hopper 80 ′ (hereinafter simply referred to as “hopper 80 ′”) to the gasifier facility 14. A plurality of (for example, three in FIG. 1) hoppers 80 'are provided. Each hopper 80 'is switched to discharge char one by one during use. Accordingly, when one hopper 80 'is discharging char, the other hopper 80' is in a standby state for discharging. Connected to the hopper 80 'are an upper pressure regulating nitrogen system 81', a lower pressure regulating nitrogen system 82 ', and a fluidized nitrogen system 83'.

  The upper pressure-regulating nitrogen system 81 ′ supplies nitrogen from the upper part of the hopper 80 ′, and the pressure in the pressure vessel 110 (see FIG. 2) of the gasifier facility 14 during use of the hopper 80 ′. This is to keep the differential pressure of the pressure constant. The nitrogen flow rate of the upper pressure adjusting nitrogen system 81 ′ is controlled by the control unit 30.

  The lower pressure adjusting nitrogen system 82 'applies a pressure for delivering the char into the hopper 80'. The nitrogen flow rate of the lower pressure adjusting nitrogen system 82 ′ is controlled by the control unit 30.

The fluidized nitrogen system 83 ′ fluidizes the char around the inlet of the transfer pipe 84 ′. The nitrogen flow rate of the fluidized nitrogen system 83 ′ is controlled by the control unit 30.
An accompanying nitrogen flow (an accompanying inert gas) obtained by subtracting the nitrogen flow used for maintaining the pressure of the hopper from the nitrogen flow obtained by adding the upper pressure adjusting nitrogen system 81 ′, the lower pressure adjusting nitrogen system 82 ′, and the fluidized nitrogen system 83 ′. The flow rate) is converted into the nitrogen specific gravity, which becomes the accompanying nitrogen volume flow rate described later.

  A transport pipe (powder transport pipe) 84 ′ is connected to each hopper 80 ′. A transport pipe seal nitrogen system 85 ′ is connected to each transport pipe 84 ′ on the upstream side before the merger 86. The transfer pipe seal nitrogen system 85 'pressurizes the pressure in the transfer pipe 84' corresponding to the unused hopper 80 'to a predetermined value or more. Thereby, even if the unused hopper 80 'is released to the atmosphere, the gasifier equipment 14 side is sealed.

  The downstream ends of the transport pipes 84 ′ are connected to the merger 86 ′ so as to merge. A merging pipe (powder conveying pipe) 89 ′ is connected to the downstream side of the merging device 86 ′.

  A dilute nitrogen system (additional inert gas supply means) 90 ′ and a char flow rate adjusting valve 93 ′ are provided in the joining pipe 89 ′ in order from the upstream side. The merging pipe 89 'is not provided with the flow meter 91 and the γ-ray density meter 92 provided in the distribution pipe 89 (FIG. 3) of the pulverized coal supply system 1A of the first embodiment. This is because, unlike the pulverized coal supply system 1A, the char supply system 1B has a high temperature (for example, about 400 ° C.) and flows to a high temperature, so it is difficult to provide a flow meter.

  The diluted nitrogen system 90 ′ additionally supplies diluted nitrogen into the junction pipe 89 ′ to adjust the flow rate in the pipe of the mixed gas of char and nitrogen. The diluted nitrogen flow rate obtained by adding the diluted nitrogen of the diluted nitrogen system 90 'is set so that the in-tube flow rate of the mixed gas is equal to or higher than a predetermined threshold value. The threshold value of the flow velocity in the tube is set, for example, from a range of 1.5 m / s or more and 8 m / s or less, and is adjusted by the diluted nitrogen flow rate. The diluted nitrogen flow rate of the diluted nitrogen system 90 ′ is controlled by the control unit 30. If the flow velocity in the pipe is less than 1.5 m / s, the char is settled in the joining pipe 89 'and the conveyance becomes unstable, which is not preferable. On the other hand, if the flow velocity in the tube exceeds 8 m / s, the overall flow velocity becomes too fast and the pressure loss increases, which is not preferable.

  The opening of the char flow rate adjusting valve 93 ′ is controlled by the control unit 30, and adjusts the flow rate of the mixed gas flowing in the joining pipe 89 ′.

  The downstream end of the merging pipe 89 'is connected to the burner distributor 94'. A plurality of (for example, four in FIG. 6) branch pipes (powder conveying pipes) 95 'are connected in parallel to the burner distributor 94'. A burner 127 (see FIG. 2) is connected to the downstream side of each branch pipe 95 ′, and the mixed gas is introduced into the gasification furnace wall 111 (see FIG. 2) of the gasification furnace facility 14. .

[Calculation of mixed gas flow velocity]
Next, calculation of the flow velocity of the mixed gas flowing in the pipe of the char supply system 1B having the above configuration will be described. The calculation of the mixed gas flow velocity is basically the same as that of the first embodiment. However, since the flow rate meter for measuring the char flow rate (powder flow rate) is not provided in the joining pipe 89 ′, there is a method for obtaining the char flow rate. Different. The char flow rate is obtained as follows.

Each hopper 80 'is provided with a weight meter (powder flow rate measuring means). By measuring the time change of the flow rate, the mass flow rate of the char supplied from the hopper 80 ′ can be obtained. More specifically, the char flow rate (mass flow rate) can be obtained by dividing the weight difference between the start of use and the end of use of the used hopper 80 'by the use time of the hopper.
Char flow rate = (weight at start of use-weight at end of use) / (use time)

  The char flow rate of the hopper 80 'used immediately before is estimated to be the same as or close to the char flow rate of the hopper 80' currently used. Thus, even if the char flow rate of the hopper 80 ′ used immediately before is used, the char flow rate is gentle compared to the pulverized coal flow rate that varies depending on the load, and the amount of change is small. Absent.

  The char flow rate (solid volume flow rate) is obtained by dividing the char flow rate (mass flow rate) obtained as described above by the true char specific gravity. Here, the true char specific gravity is the specific gravity of the char itself (solid), unlike the char bulk specific gravity.

  The mixed gas flow velocity is calculated for each pipe having a different flow path cross-sectional area and / or for each branched pipe. For example, as shown in FIG. 6, the first position M1 ′ of the transport pipe 84 ′, the second position M2 ′ downstream of the char flow rate adjusting valve 93 ′ of the joining pipe 89 ′, and the third position M3 of the branch pipe 95 ′. Calculate the mixed gas flow velocity at '.

  The adjoining nitrogen volume flow that flows with the char is obtained from a filling rate relational expression (filling rate calculation data) showing the relationship between the filling rate, which is the mass ratio of char to the mixed gas, and the char flow rate. FIG. 7 shows a filling rate relational expression. This filling rate relational expression is stored in the storage unit of the control unit 30. In the figure, the horizontal axis represents the char flow rate ratio, and the vertical axis represents the filling rate. The char flow rate ratio is made dimensionless by dividing by the reference char flow rate. As a result of intensive studies, the present inventors have found that there is a certain relationship between the char flow rate (or the char flow rate ratio calculated from the char flow rate) and the filling rate. If this filling rate relational expression is obtained, the filling rate can be obtained from the char flow rate ratio calculated from the char flow rate, and as a result, the adjoining nitrogen volume flow rate can be obtained from the ratio of nitrogen flowing in the pipe.

  The seal nitrogen flow rate supplied to the conveying pipe 84 ′ of the hopper 80 ′ that is not used can be obtained by using the set value of the gasifier pressure given to the control unit. For example, since the pressure required for sealing is determined according to the gasifier pressure, a function for the gasifier pressure is set, and the seal nitrogen flow rate is calculated according to this function.

  By adding the char flow rate (solid volume flow rate) obtained as described above and the accompanying nitrogen volume flow rate, the volume flow rate of the mixed gas flowing in the pipe of the transfer pipe 84 ′ is obtained. By dividing by the cross-sectional area of the flow path, the mixed gas flow velocity at the position M1 ′ is obtained. Further, by adding the volume flow rate of the mixed gas (char flow rate (solid volume flow rate) and adjoining nitrogen volume flow rate), the seal nitrogen flow rate, and the diluted nitrogen flow rate, the diluted nitrogen system 90 ′ on the downstream side of the merger 86 ′ A volumetric flow rate of the mixed gas flowing in the pipe obtained by adding up the merging pipes 89 ′ after the merging point is obtained. By dividing the volume flow rate of the mixed gas by the flow path cross-sectional area of each pipe, the mixed gas flow velocity at each position M2 ', M3' is obtained.

[Control of dilute nitrogen flow rate]
As described above, for example, when the mixed gas flow velocity at each position M1 ′, M2 ′, M3 ′ is obtained, the control unit is the smallest among the preselected positions such as each position M1 ′, M2 ′, M3 ′. A minimum mixed gas flow rate is selected, and it is determined whether or not this minimum mixed gas flow rate is greater than a predetermined threshold value (for example, selected from a range of 1.5 m / s to 8 m / s in this embodiment). When the minimum mixed gas flow rate is equal to or higher than a predetermined threshold value, the flow rate of the diluted nitrogen supplied from the diluted nitrogen system 90 ′ is kept constant without changing. When the minimum mixed gas flow rate becomes less than the predetermined threshold value, the diluted nitrogen flow rate is increased by a predetermined amount, and when the threshold value is exceeded, the diluted nitrogen flow rate is maintained. Further, an upper limit value obtained by adding a predetermined amount from the threshold value may be provided, and the diluted nitrogen flow rate may be decreased when the upper limit value is exceeded (for example, when the mixed gas flow rate exceeds 8 m / s).

According to this embodiment, there exist the following effects.
When the mixed gas flow velocity calculated by the control unit 30 is less than a predetermined threshold, the flow rate of diluted nitrogen supplied from the diluted nitrogen system 90 ′ to the joining pipe 89 ′ is increased. Thereby, it can suppress that mixed gas flow velocity becomes more than a predetermined threshold value, char settles in piping, and conveyance failure arises. As described above, since the determination is made based on the mixed gas flow velocity, there is no need to switch the control according to the coal type of the pulverized coal, and stable char conveyance (powder conveyance) can be realized.

  The control unit 30 includes a filling rate relational expression showing a relationship between a filling rate, which is a mass ratio of char to the mixed gas, and a char flow rate in the storage unit of the control unit. Using this filling rate relational expression, the filling rate is calculated from the char flow rate ratio calculated from the char flow rate, and the adjoining nitrogen flow rate in the mixed gas is calculated. In addition, a function indicating a relationship between the gasification furnace pressure and the seal nitrogen flow rate is set and provided in the storage unit of the control unit. According to this function, the seal nitrogen flow rate is calculated from the set value of the gasifier pressure given to the control unit. Then, the mixed gas flow rate is obtained from the added value of the accompanying nitrogen flow rate, char flow rate, seal nitrogen flow rate, and diluted nitrogen flow rate. In this way, the mixed gas flow rate can be obtained without measuring the char flow rate or the nitrogen flow rate at each position where the mixed gas flow rate is evaluated, and complicated control becomes unnecessary.

  If the cross-sectional areas of the pipes are different or the pipes are branched, the mixed gas flow velocity will be different at each location. Therefore, the mixed gas flow rate is calculated for each pipe having a different channel cross-sectional area and / or for each branched pipe, and the dilute nitrogen flow rate is increased based on the smallest mixed gas flow rate to determine the mixed gas flow rate. Therefore, the char does not settle in the pipe and the conveyance becomes unstable, and even if the char property changes with the change in the property of the pulverized coal fuel (powder fuel). Char can be supplied stably.

  The mass flow rate of the char is estimated based on the change in the weight of the char stored in the hopper 80 '. This eliminates the need for a sensor such as a flow meter for measuring the char flow rate.

  Note that the mixed gas flow rate may be calculated from the measured nitrogen flow rate without using the filling rate relational expression as in the modification of the first embodiment described with reference to FIG.

  In each of the above-described embodiments, pulverized coal or char has been described as an example of pulverized fuel. However, the present invention is not limited to this, and the coal is other carbon-containing solid fuel such as high-grade coal or low-grade coal. However, it is not limited to coal, and may be biomass used as an organic resource derived from renewable organisms. For example, thinned wood, waste wood, driftwood, grass, waste It can also be applied to other pulverized fuels obtained by pulverizing materials, sludge, tires, and recycled fuels (pellets and chips) made from these.

1A Pulverized coal supply system (Powder fuel supply device)
1B Char supply system (powder fuel supply device)
10 Coal gasification combined power generation facility (gasification combined power generation facility)
DESCRIPTION OF SYMBOLS 11 Coal supply equipment 11a Coal supply line 14 Gasification furnace equipment 15 Char recovery equipment 16 Gas purification equipment 17 Gas turbine 18 Steam turbine 19 Generator 20 Waste heat recovery boiler 30 Control part 41 Compressed air supply line 42 Air separation equipment 43 1st Nitrogen supply line 45 Second nitrogen supply line 46 Char return line 47 Oxygen supply line 49 Gas generation line 51 Dust collection facility 52 Supply hopper 53 Gas discharge line 61 Compressor 62 Combustor 63 Turbine 64 Rotating shaft 65 Compressed air supply line 66 Fuel Gas supply line 67 Combustion gas supply line 68 Booster 69 Turbine 70 Exhaust gas line 71 Steam supply line 72 Steam recovery line 74 Gas purification equipment 75 Chimney 80 Pulverized coal supply hopper 80 'Char supply hopper 81, 81' Upper pressure control nitrogen system 81a Flow meter (Inert gas flow measurement hand Step)
82, 82 'lower pressure adjustment nitrogen system 82a flow meter (inert gas flow measuring means)
83, 83 'Fluidized nitrogen system 83a Flow meter (Inert gas flow measuring means)
84,84 'Conveying pipe (powder conveying pipe)
85, 85 'Conveying pipe seal nitrogen system 86, 86' Confluence 87 Confluence conveying pipe 88 Distributor 89 Distributing piping (powder conveying piping)
89 'Junction piping (powder transfer piping)
90,90 'diluted nitrogen system (additional inert gas supply means)
91 Flowmeter (powder flow rate measuring means)
92 γ-ray density meter (powder density measuring means)
93 Pulverized coal flow control valve 93 'Char flow control valve 94, 94' Burner distributor 95, 95 'Branch pipe (powder transfer pipe)
96 Gamma ray density meter 101 Gasification furnace 102 Syngas cooler 110 Pressure vessel 111 Gasification furnace wall 115 Annulus part 116 Combustor part 117 Diffuser part 118 Reductor part 121 Gas outlet 122 Slag hopper 126 Burner 127 Burner 131 Evaporator 132 Superheater 134 Charcoal 154 Internal space 156 External space

Claims (8)

A powder transport pipe for transporting a mixed gas containing a mixed gas of a powdered fuel and an accompanying inert gas transported accompanying the powdered fuel;
A burner connected to the downstream end of the powder conveying pipe and supplying a mixed gas toward a gasification furnace for gasifying the pulverized fuel;
An additional inert gas supply means connected to the powder conveying pipe and additionally supplying an additional inert gas;
A control unit for calculating a mixed gas flow rate and a mixed gas flow rate flowing in the powder conveying pipe;
With
When the mixed gas flow rate calculated from the mixed gas flow rate and the cross-sectional area of the powder transport pipe is less than a predetermined threshold, the control unit supplies the additional inert gas flow rate supplied from the additional inert gas supply unit. Increase the powder fuel supply device. The control unit includes, in a storage unit, filling rate calculation data indicating a relationship between a filling rate which is a mass ratio of the pulverized fuel to a mixed gas in the powder transport pipe and a flow rate of the pulverized fuel,
The filling rate is calculated from the powder flow rate using the filling rate calculation data from the set value of the powder flow rate, the flow rate of the accompanying inert gas is calculated using the filling rate, and the gasification furnace Calculate the seal inert gas flow rate from the set pressure value,
The powder flow rate, the accompanying inert gas flow rate, and the additional inert gas flow rate, or the powder flow rate, the accompanying inert gas flow rate, the additional inert gas flow rate, and the seal inert gas flow rate, the mixing. The pulverized fuel supply device according to claim 1, wherein the gas flow rate is calculated. A powder flow rate measuring means for measuring a powder flow rate which is a mass flow rate of the pulverized fuel flowing in the powder transfer pipe;
An inert gas flow rate measuring means for measuring a flow rate of the inert gas supplied to the powder transfer pipe;
With
The said control part calculates a mixed gas flow rate from the said powder flow rate measured by the said powder flow rate measurement means, and the said inert gas flow rate measured by the said inert gas flow rate measurement means. Powder fuel supply device. A supply hopper for supplying pulverized fuel to the powder transfer pipe;
Powder weight measuring means for measuring the weight of the pulverized fuel stored in the supply hopper;
With
The said control part estimates the powder flow rate which is the mass flow rate of the pulverized fuel which flows through the inside of the said powder conveyance piping based on the weight change of the pulverized fuel obtained by the said powder weight measurement means. The pulverized fuel supply device described in 1.   The control unit calculates a mixed gas flow rate for each of the powder transport pipes having different flow path cross-sectional areas and / or for each of the branched powder transport pipes, and the smallest mixed gas flow speed is less than a predetermined threshold value. In this case, the pulverized fuel supply device according to any one of claims 1 to 4, wherein the flow rate of the additional inert gas supplied from the additional inert gas supply means is increased. A pulverized fuel supply device according to any one of claims 1 to 5,
The gasification furnace to which pulverized fuel is supplied from the pulverized fuel supply device;
Equipped with gasifier equipment. A gasifier facility according to claim 6;
A gas turbine that is rotationally driven by burning at least a portion of the product gas generated in the gasifier facility;
A steam turbine that is rotationally driven by steam generated by an exhaust heat recovery boiler that introduces turbine exhaust gas discharged from the gas turbine;
A generator rotationally coupled to the gas turbine and the steam turbine;
Gasification combined power generation facility equipped with. A powder transport pipe for transporting a mixed gas containing a mixed gas of a powdered fuel and an accompanying inert gas transported accompanying the powdered fuel;
A burner connected to the downstream end of the powder conveying pipe and supplying a mixed gas toward a gasification furnace for gasifying the pulverized fuel;
An additional inert gas supply means connected to the powder conveying pipe and additionally supplying an additional inert gas;
A control unit for calculating a mixed gas flow rate and a mixed gas flow rate flowing in the powder conveying pipe;
A method for controlling a pulverized fuel supply apparatus comprising:
Powder that increases the flow rate of the additional inert gas supplied from the additional inert gas supply means when the mixed gas flow rate calculated from the cross-sectional area of the mixed gas flow rate and the powder transfer pipe is less than a predetermined threshold value Control method of fuel supply device.

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