KR20020034448A - Control circuit and method of starting system for boiler - Google Patents

Abstract

The present invention newly starts a boiler combustion chamber purge configuration and a gas fuel piping purge configuration circuit for smooth restarting when a large-sized natural boiler installed in a cogeneration plant is started after large, heavy repair and tripped during normal operation. The present invention relates to a boiler starting system control circuit and method for shortening the time and preventing the risk of a safety accident due to gas dissipation when the waterside and gas piping seal ports are destroyed.

More specifically, the power of the power generation equipment and the control apparatus is normal 403, the blowers 102 and 103 are driven 404, the air dampers 105 to 107 are all opened 405, and the air flow is continuously continuous. If the purge start signal 402 is applied when the fuel shutoff valve 203 is all closed 407 when the fuel shutoff valve 203 is closed 407, the boiler start system is reset 401 after 5 minutes by a timer. In the boiler starting reset circuit, a boiler combustion chamber purge circuit 409 in which the fuel shutoff valve 203 is replaced with fuel gas burner valves 205 to 213, and five minutes by the timer are used for the blowers 102 and 103. Gas running time is set to 60 minutes, the air flow is 25% or more of the maximum continuous rated output, the driving time of the press-fitting blower 103 is set within 30 minutes, and the gas fuel for applying the reset switch of the boiler starting system is applied. Beam comprising a pipe purge circuit 408, characterized in that Provide multiple activation system control circuit.

The present invention relates to a boiler starting system control circuit so that the nitrogen purge can be stably carried out without breaking the water seal and seal ports when the nitrogen purge in the gas pipe after the boiler stops and the fuel cutoff valve 203 is closed. The circuit was reconfigured so that the combustion chamber purge could be purged only in a state where the fuel cutoff valve 203 was opened, and the blowers 102 and 103 were operated at the time of the boiler trip. The new circuit was set up to enable the boiler to be reset within minutes, contributing significantly to the stable operation and productivity improvement of the steel mill by shortening the startup time of the cogeneration plant.

Description

CONTROL CIRCUIT AND METHOD OF STARTING SYSTEM FOR BOILER}

The present invention newly starts a boiler combustion chamber purge configuration and a gas fuel piping purge configuration circuit for smooth restarting when a large-sized natural boiler installed in a cogeneration plant is started after large, heavy repair and tripped during normal operation. The present invention relates to a boiler starting system control circuit and method for shortening the time and preventing the risk of a safety accident due to gas dissipation when the waterside and gas piping seal ports are destroyed.

The problems of the prior art will be described with reference to FIGS. 1 and 2. First, Figure 1 is a general boiler combustion flow chart, the combustion air sucked from the inlet blower 103 is subjected to heat exchange in the waste gas heat exchanger 104, the upper, middle and lower air dampers 105 to 107 of the burner Air is supplied through the burner and the air shortage of the burner is supplemented by opening the air supplement supply damper 108 so as to perform secondary combustion, and the burned gas mixed with the fuel in the burner is discharged through the chimney (102). 101 shows the discharge to step. 2 is a flow chart of a general boiler gas fuel, in which a cogeneration power plant boiler as a self-generating facility of a steel mill is burning various by-product gases (BFG, COG, LDG) and heavy oil fuel (H-OIL) generated in the steel mill. When the boiler is restarted after repairing due to a breakdown of the boiler during normal operation or during normal operation, the residual temperature inside the boiler is high because of the high temperature inside the boiler. Fuel control valve (214) is installed in the state where the upper, middle, and lower burner valves (205 to 213) are completely closed after water sealing is performed to fill the V-shaped pipe to maintain water tightness. 202 and fuel shutoff valve 203 are opened, burner side dissipation valve 204 is opened, and nitrogen supply control valve 201 is opened to carry out nitrogen purge in the TM pipe. However, in order to perform the boiler start reset (401) as in the prior art indicated by the solid line of FIG. 4, the various fuel (BFG, COG, LDG, H-OIL) shutoff valves 203 must be closed (407). During the nitrogen purge, the fuel shutoff valve 203 and the nitrogen supply control valve 201 are closed to reset the boiler, and the fuel shutoff valve 203 and the nitrogen supply control valve 201 are opened again to carry out the nitrogen purge. This causes the delay of purge time in the gas pipe and delay of boiler start-up due to the oxygen inflow generated at the time of gas pipe purge stop, and the loss of energy due to the production of by-product gas at the steelworks. When the boiler interlock test (INTERLOCK TEST) is performed and the fuel shutoff valve 203 is closed, the water seal side 214 and the gas due to the increase in nitrogen pressure in the gas pipe. The seal ports 215 and 216 are destroyed to cause worker poisoning accidents and gas dissipation accidents due to the release of toxic gases. When the boiler trips during normal operation of the boiler, the gas fuel shutoff valve 203 and each burner valve 204 to 212 Even if the inlet blower 103 and the waste gas heat exchanger 104 are operated normally, the boiler start-up delay is delayed even if the boiler combustion chamber is purged due to the conventional boiler combustion chamber purge system logic circuit (solid line zone in FIG. 4). The frequent occurrence of this phenomenon caused a huge impact on costs, such as power shortages in steel mills and energy losses due to the release of by-product gas.

The present invention is to solve the problems as described above to ensure that the boiler start reset 302 can be carried out even during the nitrogen purge in the gas pipe as shown in Figure 3 when the gas fuel shutoff valve 203 when nitrogen purge in the gas pipe When it is closed 501, the nitrogen supply control valve 201 and the burner gas dissipation valve 204 are automatically closed 504, thereby preventing the accident and the inflow of gas in the gas pipe. The prolonged nitrogen purge time in the gas pipe is prevented from being prolonged, and in case of a trip accident that stops during the normal operation of the boiler, the press-fit blower 103 and the waste gas heat exchanger 104 operate normally, and due to other factors such as equipment and generator turbine abnormalities. If judged, boiler start-up reset room without boiler boiler purge Its purpose is to shorten the start-up time and to contribute to cost reduction at the steel mill by operating the cogeneration plant at a short time.

The present invention is to achieve the above object, the power of the power plant and the control device is a normal 403, the blowers (102, 103) are driven 404, the air dampers (105 to 107) are all open (405), When the air flow is 25% or more of the maximum continuous rated output 406 and the fuel shutoff valves 203 are all closed 407, if the purge start signal 402 is applied, the boiler starts the system after 5 minutes by a timer. In the boiler starting reset circuit which is reset 401, the boiler combustion chamber purge circuit 409 in which the fuel shutoff valve 203 is replaced with the fuel gas burner valves 205 to 213, and 5 minutes by the timer, The drive time of the blowers (102, 103) is 60 minutes, the air flow is 25% or more of the maximum continuous rated output, the drive time of the press-fit blower (103) is set within 30 minutes, the reset switch of the boiler starting system Including a gas fuel piping purge circuit 408 for applying The boiler start-up is that on the system control circuit according to claim.

1 is a general boiler combustion flow chart,

2 is a general boiler gas fuel flow diagram,

Figure 3 is a gas piping nitrogen purge control method of the present invention,

4 is a boiler start reset circuit diagram of the present invention;

Explanation by the main part of the drawing

10: boiler 101: chimney

102: manned blower 103: pressurized blower

104: (waste gas) heat exchanger 105,106,107: (burner upper, middle, lower) air damper

108: air supplement supply damper 201: nitrogen supply control valve

202: (gas fuel) control valve 203: (gas fuel) shutoff valve

204: dissipation valve 205 to 213: gas fuel burner valve

214: Water sealing valve (valve) 215 to 216: Gas seal port (GAS SEAL POT)

302: boiler start reset 402: purge start

403: Normal power plant and control device

404: blower operation 405: air damper fully open

406: 25% or more of air flow

408: (Gas Fuel) Piping Fuzzy Circuit

409: Boiler Combustion Chamber Purge Configuration Conditions

501: gas fuel shutoff valve closing request

502: request for closing the nitrogen supply control valve and the discharge valve

503: nitrogen supply control valve and dissipation valve closed

504: nitrogen supply control valve and burner discharge valve closed

Hereinafter, with reference to the accompanying drawings for an embodiment of the present invention will be described in detail.

3 is related to the gas pipe purge control method of the present invention, the nitrogen supply control valve 201 and the burner discharge valve 204 automatically when the situation where the gas fuel shutoff valve 203 is closed (501) occurs The logic circuit is newly configured to be closed (502) so that the nitrogen supply control valve (201) and the burner discharge valve (204) are automatically closed when the fuel shutoff valve (203) is closed during the nitrogen purge of the gas fuel line. In addition, the phenomenon of water seal and seal pod destruction caused by the increase in nitrogen pressure in the gas pipe was prevented in advance, and the flow of oxygen was prevented by blocking the discharge valve 204 to shorten the purge time. Reference numeral 503 in FIG. 3 denotes a conventional circuit.

Figure 4 is a boiler start reset circuit diagram of the present invention to perform the boiler start reset 302 of the nitrogen purge in the gas pipe in the water seal valve state of the existing power generation equipment automatic operation system, automatic burner device, power generation equipment automatic start system, etc. The power supply of the power generation equipment and the control device is normal (403), the manned blower (102) and the press-fit blower (103) are driven (404), and the air dampers (105 to 107) at the top, middle, and bottom of the burner are all turned on. When the air flow is set to 25% or more of the maximum continuous rated output (MCR) and the fuel shutoff valves 203 are all closed (407), the purge start start signal (402) is applied to the nitrogen supply control valve of the gas pipe again. The boiler reset 302 should be performed after closing the fuel control valve 202 and the burner discharge valve 204 and starting the combustion chamber purge of the boiler 402 to prevent the nitrogen purge in the gas pipe from being stopped. Wanna burner In the state where all the valves 205 to 213 (dashed line display) are closed (409), a boiler combustion chamber purge circuit (409: point island display) has been newly established to enable the boiler reset 302 even when the fuel shutoff valve 203 is opened. In addition, conventionally, the air dampers 105 to 107 of each stage are opened while each control power source is normal and the induced blower 102 and the press-fit blower 103 are started and the fuel shutoff valve 203 is closed. When the flow rate satisfies the condition of 25% or more of the maximum continuous rated output (AIR FLOW 120TON / HR), the boiler starts to be reset (302) after 5 minutes after the purge start (402). If the reset circuit is set, but the boiler combustion chamber abnormality during the operation of the boiler, the main fuel of the boiler must be shut off urgently due to the abnormality of the water supply and other safety protection systems or generators and turbines, not the blowers (102,103). Was also established: (dotted display 408), the boiler combustion chamber purge start 402 without resetting the boiler 302, the embodiment 401, the fuel shut-off valve 201 is open doeyeo boiler purge gas circuit to allow the fuel pipe purge.

The present invention is to solve the problems as described above to ensure that the boiler start reset 302 can be carried out even during the nitrogen purge in the gas pipe as shown in Figure 3 when the gas fuel shutoff valve 203 when nitrogen purge in the gas pipe When it is closed 501, the nitrogen supply control valve 201 and the burner gas dissipation valve 204 are automatically closed 504, thereby preventing the accident and the inflow of gas in the gas pipe. The prolonged nitrogen purge time in the gas pipe is prevented from being prolonged, and in case of a trip accident that stops during the normal operation of the boiler, the press-fit blower 103 and the waste gas heat exchanger 104 operate normally, and due to other factors such as equipment and generator turbine abnormalities. If it is determined, the boiler start-up reset room without performing the boiler combustion chamber purge (conventional boiler start-up reset circuit diagram: solid line zone of FIG. 4) Its purpose is to shorten the start-up time and to contribute to cost reduction at the steel mill by operating the cogeneration plant at a short time.

The present invention is to achieve the above object, the power of the power plant and the control device is a normal 403, the blowers (102, 103) are driven 404, the air dampers (105 to 107) are all open (405), When the air flow is 25% or more of the maximum continuous rated output 406 and the fuel shutoff valves 203 are all closed 407, if the purge start signal 402 is applied, the boiler starts the system after 5 minutes by a timer. In the boiler starting reset circuit to be reset 401, the boiler combustion chamber purge circuit 409 in which the fuel shutoff valve 203 is replaced with fuel gas burner valves 205 to 213, and 5 minutes by the timer are described. Set the drive time of the blowers 102 and 103 to 60 minutes, the air flow to be 25% or more of the maximum continuous rated output, set the drive time of the press-fit blower 103 to within 30 minutes, and reset the reset switch of the boiler starting system. It comprises a gas fuel piping purge circuit 408 to apply It relates to a boiler starting system control circuit characterized in that.

The present invention relates to a boiler starting system control circuit to ensure a stable nitrogen purge without accidental breakage of the water seal and seal ports when the nitrogen purge in the gas pipe after the boiler stops and the fuel cutoff valve 203 is closed. The circuit was reconfigured so that the combustion chamber purge could be purged only in a state where the fuel cutoff valve 203 was opened, and the blowers 102 and 103 were operated at the time of the boiler trip. The new circuit was set up to enable the boiler to be reset within minutes, contributing significantly to the stable operation and productivity improvement of the steel mill by shortening the startup time of the cogeneration plant.

Claims (2)

The power of the power plant and the control device is normal (403), the blowers (102, 103) are driven (404), the air dampers (105-107) are all open (405), and the airflow is 25% of the maximum continuous rated output. If the purge start signal 402 is applied when the fuel shutoff valves 203 are all closed 407, In the boiler start reset circuit in which the boiler start system is reset 401 after 5 minutes by a timer, A boiler combustion chamber purge circuit 409 in which the fuel shutoff valve 203 is replaced with fuel gas burner valves 205 to 213; 5 minutes by the timer, The driving time of the blowers (102, 103) is 60 minutes, The air flow is at least 25% of the maximum continuous rated power, And a gas fuel piping purge circuit (408) for setting the driving time of the press-fit blower (103) to within 30 minutes and applying a reset switch of the boiler starting system. In the boiler starting system, And a logic circuit is provided so that when the gas fuel shutoff valve (203) is closed (501), the nitrogen supply control valve (201) and the burner discharge valve (204) are automatically closed (502).