JP6079430B2 - Operation method of circulating fluidized bed gasification gas generation system - Google Patents

Description

  The present invention relates to a method for operating a circulating fluidized bed gasified gas generation system that generates gasified gas using a circulating fluidized bed.

  In recent years, a technology for generating gasification gas by gasifying gasification raw materials such as coal, biomass, tire chips and the like has been developed instead of natural gas, which is expected to increase in price. The gasified gas thus generated is used for power generation systems, hydrogen production, synthetic fuel (synthetic petroleum) production, chemical fertilizer (urea) and other chemical products. Among gasification raw materials used as raw materials for gasification gas, coal, in particular, has a recoverable period of about 150 years, which is more than three times the extractable period of oil, and reserves are unevenly distributed compared to oil. Therefore, it is expected as a natural resource that can be supplied stably over a long period of time.

  As a technology for gasifying gasified raw materials such as coal, the fluidized medium is circulated between a combustion furnace for heating the fluidized medium and a gasification furnace (fluidized bed furnace) for gasifying the gasified raw material. A technique (steam gasification) in which a fluidized bed of a fluidized medium is formed in the gasification furnace by supplying steam at about 800 ° C. to the furnace, and the gasification raw material is gasified in the gasification furnace. ) Has been developed.

  When starting the circulating fluidized bed gasification gas generation system that circulates the fluidized medium between the combustion furnace and the gasification furnace described above, the temperature of the fluidized medium is normal temperature (for example, 30 ° C.). When water vapor is supplied to the gasifier, the water vapor condenses in the gasifier to become water (liquid), the fluidity of the fluidized medium is impaired, and the equipment and piping that make up the circulating fluidized bed gasification gas generation system are blocked. There is a risk that.

  Therefore, as a start-up operation of the circulating fluidized bed gasification gas generation system, first, normal temperature air is supplied to the combustion furnace and the gasification furnace to circulate the fluid medium, and the combustion furnace is started to heat the fluid medium. The technique to do is disclosed (for example, patent document 1). In the technique of Patent Document 1, when the temperature of the fluidized medium reaches a predetermined temperature, the flow rate of air supplied to the gasification furnace is gradually reduced, and the amount of water vapor supplied to the gasification furnace is gradually increased. Has increased. Then, when the switching from the gas air supplied to the gasification furnace to the water vapor is completed, introduction of the gasification raw material into the gasification furnace is started, and generation of gasification gas (normal operation) is started.

JP 2009-227752 A

  However, since air and water vapor have different physical properties such as mass density and viscosity, simply making the flow rate for reducing air (reduction flow rate of air) and the flow rate for increasing water vapor (increase flow rate of water vapor) equal, The flow state of the fluid medium will fluctuate greatly. In addition, since the frequency of performing the start-up operation is extremely low, adjustment of the reduced flow rate of air and the increased flow rate of water vapor is often performed according to an operation input by an operator without providing a special control device. In this case, a time lag occurs between the reduction of air and the increase of water vapor, and the flow state of the fluid medium greatly fluctuates. If it does so, there exists a possibility that a flowing medium may cause circulation failure and a flowing medium may accumulate in the place which is not assumed.

  Here, if the reduced flow rate of air and the increased flow rate of water vapor are changed little by little (if the rate of change is reduced), the fluctuation range of the flow state can be suppressed. Although it is possible to avoid the accumulation of the medium, an enormous amount of time is required only for switching from air to water vapor. For this reason, development of the technique which shortens the time which starts is avoided while avoiding the accumulation of the fluid medium in the location which is not assumed.

  Then, this invention aims at provision of the operating method of the circulating fluidized bed gasification gas production system which can shorten starting time, avoiding deposition of the fluid medium in the location which is not assumed.

  In order to solve the above-mentioned problem, the operation method of the circulating fluidized bed gasified gas generation system according to the present invention is such that a fluidized bed of a fluidized medium is formed and gasified raw material is gasified with heat of the fluidized bed. A gasification furnace for generating gas, a fluidizing medium from the gasification furnace, a combustion furnace for heating the fluidizing medium, a fluidizing medium heated by the combustion furnace, and a combustion exhaust gas generated in the combustion furnace are separated. And a medium separator for introducing the fluidized medium into the gasifier, the medium separator is provided between the medium separator and the gasifier, and the fluidized medium flows between the medium separator and the gasifier, and the medium An inlet loop seal that seals one or both of the inflow of gas from the separator to the gasifier and the outflow of gasified gas generated in the gasifier to the medium separator, and the gasifier and the combustion furnace Between the gasifier and the fuel The fluidizing medium is flowed to and from the furnace, and either one or both of the gasification gas generated in the gasification furnace and the gas inflow from the combustion furnace to the gasification furnace are sealed. An operation method of a circulating fluidized bed gasification gas generation system comprising an outlet loop seal, the step of supplying air to the inlet loop seal, the gasification furnace, and the outlet loop seal to flow the fluid medium; When determining whether the temperature of the fluidized medium is equal to or higher than the temperature at which the water vapor is not condensed, and when determining that the temperature of the fluidized medium is equal to or higher than the temperature at which the water vapor is not condensed, either the gasification furnace or the outlet loop seal Circulating the fluidized medium in the circulating fluidized bed gasification gas generation system by stopping the supply of air to one or both mechanisms and depositing the fluidized medium on the mechanism where the supply of air is stopped While reducing the flow rate of the air supplied to the inlet loop seal and the mechanism in which the supply of air is not stopped among the one or both of the gasification furnace and the outlet loop seal, The method includes a step of increasing the flow rate and a step of supplying water vapor to the mechanism in which the fluid medium is deposited by stopping the supply of air.

  According to the present invention, it is possible to shorten the start-up time while avoiding the accumulation of the fluid medium at an unexpected location.

It is a figure for demonstrating the specific structure of a circulating fluidized bed gasification gas production | generation system. It is a flowchart for demonstrating the flow of a process of the operating method of a circulating fluidized bed gasification gas production system.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for facilitating the understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

(Circulating fluidized bed gasification gas generation system 100)
FIG. 1 is a diagram for explaining a specific configuration of a circulating fluidized bed gasified gas generation system 100. As shown in FIG. 1, the circulating fluidized bed gasification gas generation system 100 includes a combustion furnace 110, a medium separator (cyclone) 112, an inlet loop seal 114, an outlet loop seal 116, a gasifier 130, The wind box 140 includes a first supply unit 160, a second supply unit 170, valves 180a, 180b, and 180c, a temperature measurement unit 190, and a control unit 192. In FIG. 1, the flow of a substance such as a fluidized medium, gasified raw material, gasified gas, air, water vapor, and combustion exhaust gas is indicated by solid arrows, and the signal flow is indicated by broken arrows.

  In the present embodiment, the circulating fluidized bed gasification gas generation system 100 circulates as a heat medium a fluid medium composed of sand such as dredged sand (silica sand) having a particle size of about 300 μm as a whole. Specifically, the fluid medium is first heated to about 900 ° C. to 1000 ° C. in the combustion furnace 110 and introduced into the medium separator 112 together with the combustion exhaust gas. In the medium separator 112, the combustion exhaust gas and the high-temperature fluid medium are separated, and the separated combustion exhaust gas is heat recovered by a heat exchanger (for example, a boiler) not shown. On the other hand, the high-temperature fluid medium separated by the medium separator 112 is introduced into the gasification furnace 130 through the inlet loop seal 114.

  An inlet loop seal 114 is provided between the media separator 112 and the gasifier 130. The inlet loop seal 114 contains a fluid medium, and a fluid gas is supplied from one of a first supply unit 160 and a second supply unit 170 described later, and the fluid medium is fluidized by the fluid gas. . As a result, the inlet loop seal 114 is filled with the fluid medium, and the inlet loop seal 114 flows into the gasifier 130 from the medium separator 112 and the gas generated in the gasifier 130. Either or both of the outflow of the chemical gas or the flowing gas to the medium separator 112 will be sealed.

  The fluid medium introduced from the medium separator 112 into the gasification furnace 130 via the inlet loop seal 114 flows by the fluid gas supplied from the wind box 140 described later, and the combustion furnace 110 via the outlet loop seal 116. Returned to

  The outlet loop seal 116 is provided between the gasification furnace 130 and the combustion furnace 110. The outlet loop seal 116 accommodates a fluid medium. The fluid gas is supplied from one of the first supply unit 160 and the second supply unit 170, and the fluid medium is fluidized by the fluid gas. As a result, the outlet loop seal 116 is filled with a fluid medium, and the outlet loop seal 116 flows out of the gasification gas generated in the gasification furnace 130, the flowing gas into the combustion furnace 110, and the gas from the combustion furnace 110. Either or both of the inflows of gas (combustion exhaust gas) to the chemical conversion furnace 130 are sealed.

  As described above, in the circulating fluidized bed gasified gas generation system 100 according to the present embodiment, the fluidized medium includes the combustion furnace 110, the medium separator 112, the inlet loop seal 114, the gasifier 130, and the outlet loop seal 116. By moving in order and re-introducing into the combustion furnace 110, they are circulated.

  A wind box 140 is provided below the gasification furnace 130. When the circulating fluidized bed gasification gas generation system 100 is normally operated, the first supply unit 160 is driven, and the flowing gas (here, water vapor) supplied from the first supply unit 160 is converted into the wind box 140. Is supplied into the gasifier 130 from the bottom of the gasifier 130. Thus, by supplying water vapor to the high-temperature fluid medium introduced from the medium separator 112, a fluidized bed (bubble fluidized bed) is formed in the gasification furnace 130.

  A gasification raw material (solid raw material) such as coal, biomass, and tire chips is introduced into the gasification furnace 130, and the introduced gasification raw material is generated by heat and steam of about 800 ° C. to 900 ° C. that the fluidized medium has. It is gasified, and thereby gasified gas (syngas) is generated.

  Here, the start-up operation and the normal operation of the circulating fluidized bed gasification gas generation system 100 will be described. The state before the circulating fluidized bed gasification gas generation system 100 is started, that is, the circulating fluidized bed gasification gas generation system 100. In the stopped state, the fluid medium accommodated in the gasification furnace 130 is at room temperature (for example, 30 ° C.). Therefore, when water vapor is suddenly supplied as the flowing gas to the inlet loop seal 114, the outlet loop seal 116, and the gasification furnace 130 when starting the operation, the inlet loop seal 114, the outlet loop seal 116, and the gasification furnace 130 are suddenly supplied. The water vapor condenses into water (liquid) and the fluidity of the fluid medium is impaired (the fluid medium is fixed), and the inlet loop seal 114, the outlet loop seal 116, the gasification furnace 130, and the piping connecting them are provided. There is a risk of blockage.

  Therefore, when starting up the circulating fluidized bed gasification gas generation system 100, first, a fluid gas such as air that does not condense even at room temperature is supplied to the inlet loop seal 114, the outlet loop seal 116, and the gasification furnace 130. A fluidized bed is formed in the inlet loop seal 114, the outlet loop seal 116, and the gasification furnace 130. Then, with the formation of the fluidized bed, the fluidized medium floats up, the vertical height of the fluidized medium accommodated in the inlet loop seal 114, the outlet loop seal 116, and the gasification furnace 130 is increased. It overflows from the gasification furnace 130, is sent to the outlet loop seal 116, and is introduced into the combustion furnace 110. As described above, when the formation of the fluidized bed is started in the gasification furnace 130, the circulation of the fluidized medium is started.

  Then, by starting the operation of the combustion furnace 110, the temperature of the circulating fluid medium rises, and the temperature of the fluid medium introduced into the gasification furnace 130 becomes a temperature at which water vapor is not condensed (for example, about 200 ° C.). Then, the flowing gas supplied to the inlet loop seal 114, the outlet loop seal 116, and the gasification furnace 130 is switched to a gasifying agent (water vapor) for gasifying the gasification raw material, and normal operation is started. .

  Thus, when starting the gasification furnace 130, air is supplied and when normal operation is performed, water vapor is supplied. Therefore, when moving from the start operation to normal operation, the flowing gas is converted from air to water vapor. Will be switched to. Hereinafter, a specific configuration for switching the flowing gas will be described.

  As shown in FIG. 1, a wind box 140 is provided below the gasification furnace 130. The air box 140 is provided with a plurality of nozzles, and the plurality of nozzles are arranged in the gasification furnace 130.

  The first supply unit 160 is connected to the inlet loop seal 114, the wind box 140, and the outlet loop seal 116 through the pipe 162, and in accordance with a control command from the control unit 192 described later, the inlet loop seal 114, the wind box 140 (gas Steam 130 (flowing gas) is supplied to the outlet loop seal 116. The first supply unit 160 is used when switching from the startup operation to the normal operation and when performing the normal operation.

  The second supply unit 170 is connected to the inlet loop seal 114, the wind box 140, and the outlet loop seal 116 through the pipe 172, and the inlet loop seal 114, the wind box 140 (gasifier 140) according to a control command from the control unit 192. 130), air (fluid gas) is supplied to the outlet loop seal 116. The second supply unit 170 is used when performing the start-up operation and when switching from the start-up operation to the normal operation. The second supply unit 170 supplies air heated to about 200 ° C. to the inlet loop seal 114, the wind box 140, and the outlet loop seal 116 by exchanging heat with the combustion exhaust gas separated by the medium separator 112. To do.

  The valve 180 a is provided on the downstream side of the wind box 140 in the pipe 162 and upstream of the outlet loop seal 116. The valve 180 b is provided on the upstream side of the inlet loop seal 114 in the pipe 162 and on the downstream side of the first supply unit 160. The valve 180c is provided in the pipe 172. The valves 180a, 180b, and 180c are controlled to open and close by the control unit 192. The opening / closing control of the valves 180a, 180b, and 180c by the control unit 192 will be described in detail later.

  The temperature measurement unit 190 measures the temperature of the fluidized medium in the gasification furnace 130.

  The control unit 192 is composed of a semiconductor integrated circuit including a CPU (Central Processing Unit), reads programs and parameters for operating the CPU itself from the ROM, and cooperates with the RAM as a work area and other electronic circuits. Thus, the entire circulating fluidized bed gasification gas generation system 100 is managed and controlled. In the present embodiment, the control unit 192 controls the drive of the combustion furnace 110, the drive control of the medium separator 112, the drive control of the first supply unit 160, the drive control of the second supply unit 170, the valves 180a, 180b, and 180c. Perform opening and closing control.

  Below, the operating method of the circulating fluidized bed gasification gas production system 100 by the control part 192 is demonstrated.

(Operation Method of Circulating Fluidized Bed Gasified Gas Generation System 100)
FIG. 2 is a flowchart for explaining the processing flow of the operation method of the circulating fluidized bed gasified gas generation system 100. Before starting the circulating fluidized bed gasified gas generation system 100, the circulating fluidized bed gasified gas generation system 100 is in a stopped state, and the valves 180a, 180b, and 180c are in a closed state. And Further, in the operation method of the circulating fluidized bed gasified gas generation system 100 in the present embodiment, when an instruction to stop is given by an operator, the process being performed at that time is stopped.

(Start instruction determination step S310)
The control unit 192 determines whether or not an instruction indicating that the start operation by the worker is to be started has been received. And if the instruction | indication which starts starting operation is received (YES in S310), a process will be moved to air supply process S312. On the other hand, when there is no instruction indicating the start operation by the operator (NO in step S310), the standby state of the instruction indicating the start operation is maintained.

(Air supply process S312)
When receiving an instruction indicating that start-up operation is to be started, the control unit 192 opens the valves 180 a and 180 c and starts driving the second supply unit 170. Then, air is supplied to the inlet loop seal 114, the gasification furnace 130, and the outlet loop seal 116, and a fluidized bed of a fluidized medium is formed in the inlet loop seal 114, the gasification furnace 130, and the outlet loop seal 116. Thereby, circulation of a fluid medium is started.

(Heating start process S314)
The control unit 192 starts the operation of the combustion furnace 110 and the medium separator 112, and starts heating the fluidized medium.

(First temperature determination step S316)
The control unit 192 determines whether or not the temperature Tb of the fluid medium in the gasification furnace 130 measured by the temperature measurement unit 190 is equal to or higher than the temperature TA at which water vapor is not condensed. Then, when the temperature Tb of the fluid medium in the gasification furnace 130 becomes equal to or higher than the temperature TA (YES in S316), the process is moved to the circulation stop step S318. On the other hand, when the temperature Tb of the fluidized medium in the gasification furnace 130 is lower than the temperature TA (NO in S316), the process waits until the temperature Tb of the fluidized medium in the gasification furnace 130 becomes equal to or higher than the temperature TA.

(Circulation stop step S318)
When the temperature Tb of the fluid medium becomes equal to or higher than the temperature TA at which water vapor does not condense, the control unit 192 closes the valve 180a and stops supplying air to the outlet loop seal 116. As a result, the outlet loop seal 116 functions as a shut-off valve, the fluidized medium cannot move from the outlet loop seal 116 to the combustion furnace 110, and the fluidized medium accumulates on the outlet loop seal 116 and the gasifier 130. Thus, the circulation of the fluidized medium in the circulating fluidized bed gasified gas generation system 100 is stopped.

(First switching step S320)
When the circulation of the fluid medium is stopped, the control unit 192 starts driving the first supply unit 160, adjusts the opening degree of the valve 180c, and adjusts the opening degree of the valve 180b corresponding to the opening degree of the valve 180c. Then, while decreasing the flow rate of air supplied to the gasification furnace 130 and the inlet loop seal 114, the flow rate of water vapor is increased, and finally the valve 180c is closed and the driving of the second supply unit 170 is stopped. Then, only water vapor is supplied to the gasification furnace 130 and the inlet loop seal 114.

(Second switching step S322)
When the first switching step S320 is completed, the control unit 192 adjusts the opening degree of the valve 180a to gradually increase the flow rate of water vapor supplied to the outlet loop seal 116, and when the flow rate reaches a predetermined flow rate, Stop increasing.

(Second temperature determination step S324)
The control unit 192 determines whether or not the temperature Tb of the fluid medium in the gasification furnace 130 measured by the temperature measurement unit 190 is equal to or higher than a predetermined temperature TB. Here, the temperature TB is a temperature desired in the gasification furnace 130 (for example, a temperature suitable for gasification of the gasification raw material), and is, for example, 800 ° C to 900 ° C. Then, when the temperature Tb of the fluid medium in the gasification furnace 130 becomes equal to or higher than the temperature TB (YES in S324), the process is moved to the gasification step S330. On the other hand, when the temperature Tb of the fluidized medium in the gasifier 130 is lower than the temperature TB (NO in S324), the process waits until the temperature Tb of the fluidized medium in the gasifier 130 becomes equal to or higher than the temperature TB.

(Gasification step S330)
When the temperature Tb of the fluidized medium in the gasification furnace 130 becomes equal to or higher than the temperature TB, the gasification raw material is introduced into the gasification furnace 130 and normal operation is started.

(Stop instruction determination step S332)
The control unit 192 performs normal operation until a stop instruction is issued by the worker (NO in S332), and when the stop instruction is received (YES in S332), the operation process ends.

  As described above, according to the operation method of the circulating fluidized bed gasified gas generation system 100 according to this embodiment, first, air is supplied to the inlet loop seal 114, the gasifier 130, and the outlet loop seal 116 in the air supply step S312. , And the fluid medium is fluidized and circulated with air. Then, when switching the flowing gas from air to water vapor, the supply of air to the outlet loop seal 116 is temporarily stopped to stop the circulation of the flowing medium (circulation stopping step S318).

  By the way, when the flowing gas is switched from air to water vapor, when the flow rate of air supplied to the inlet loop seal 114, gasifier 130, and outlet loop seal 116 is gradually reduced and the amount of water vapor is gradually increased, Due to the difference in physical properties between water and water vapor, the flow state of the fluid medium will fluctuate greatly. In this case, the fluid medium may cause poor circulation, and the fluid medium may accumulate at an unexpected location such as between the medium separator 112 and the inlet loop seal 114.

  Therefore, in this embodiment, when the flowing gas is switched from air to water vapor, the supply of air to the outlet loop seal 116 is temporarily stopped to stop the circulation of the flowing medium, thereby intentionally supplying the gasifier 130. Deposit the fluid medium. Since the capacity of the gasification furnace 130 is large enough to accommodate the entire fluidized medium in the circulating fluidized bed gasification gas generation system 100, the fluidizing medium remains in the inlet loop even if the fluidizing medium is deposited in the gasification furnace 130. There is no risk of backflow to the seal 114. Further, since the outlet loop seal 116 and the gasification furnace 130 are made of a refractory material, even if a high-temperature fluid medium is deposited, a situation in which damage is caused can be avoided.

  As described above, according to the operation method of the circulating fluidized bed gasified gas generation system 100 according to the present embodiment, the supply timing and stop timing of air and water vapor to the inlet loop seal 114, the gasification furnace 130, and the outlet loop seal 116. It is possible to reduce the start-up time while avoiding the accumulation of fluid media at unexpected locations at low cost without adding new equipment or software. Become.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to this embodiment. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Is done.

  For example, in the above embodiment, the supply of air to the outlet loop seal 116 is stopped in the circulation stop step S318. However, the gasification furnace 130 is replaced with or in addition to the outlet loop seal 116. The supply of air may be stopped.

  It should be noted that each step of the operation method of the circulating fluidized bed gasified gas generation system of the present specification does not necessarily have to be processed in time series in the order described in the flowchart, and may include processing in parallel or by a subroutine. Good.

  INDUSTRIAL APPLICATION This invention can be utilized for the operating method of the circulating fluidized bed gasification gas production | generation system which produces | generates gasification gas using a circulating fluidized bed.

S312 Air supply process S316 First temperature determination process S318 Circulation stop process S320 First switching process S322 Second switching process 100 Circulating fluidized bed gasification gas generation system 110 Combustion furnace 112 Medium separator 114 Inlet loop seal 116 Outlet loop seal 130 Gas Furnace

Claims (1)

A gasification furnace in which a fluidized bed of a fluidized medium is formed, and gasified raw material is gasified with heat of the fluidized bed to generate a gasified gas;
A combustion furnace for introducing the fluid medium from the gasification furnace and heating the fluid medium;
A medium separator for separating the fluid medium heated by the combustion furnace and the combustion exhaust gas generated in the combustion furnace and introducing the fluid medium into the gasification furnace;
The fluid separator is provided between the medium separator and the gasifier, and causes the fluidized medium to flow between the medium separator and the gasifier, and the gas from the medium separator to the gasifier An inlet loop seal that seals either or both of the inflow and the outflow of gasification gas produced in the gasifier to the media separator;
The combustion furnace provided between the gasification furnace and the combustion furnace, causing the fluidized medium to flow between the gasification furnace and the combustion furnace, and the gasification gas generated in the gasification furnace An outlet loop seal that seals either or both of the outflow to and the inflow of gas from the combustion furnace to the gasifier;
An operation method of a circulating fluidized bed gasification gas generation system comprising:
Supplying air to the inlet loop seal, the gasifier, and the outlet loop seal to flow the fluid medium;
Determining whether the temperature of the fluidized medium is equal to or higher than a temperature at which water vapor does not condense;
When it is determined that the temperature of the fluidized medium is equal to or higher than the temperature at which water vapor does not condense, the supply of air to one or both of the gasification furnace and the outlet loop seal is stopped, and the supply of air is stopped. Depositing the fluidized medium on a stopped mechanism to stop circulation of the fluidized medium in the circulating fluidized bed gasification gas generation system;
The flow rate of water vapor while reducing the flow rate of air supplied to the inlet loop seal and the mechanism in which the supply of air is not stopped among either or both of the gasification furnace and the outlet loop seal Increasing the process,
Supplying water vapor to the mechanism in which the fluid medium is deposited by stopping the supply of air; and
A method for operating a circulating fluidized bed gasified gas generation system, comprising:

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