Operation of Ende powder gasifier

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Cold-start operation of the Ende powder gasifier – Pre-start checks: 1. Upon receiving the start-up notification, get in touch with the relevant teams. 2. Adjust the air spray tower and Venturi to ensure normal overflow. 3. Adjust the liquid level in the waste boiler drum to a normal level, keeping it between 1/2 and 2/3 of its capacity. 4. The water filling and overflow of the three water seals in the waste heat boiler are normal. 5. Check that the material level in the coal storage tank is normal, and manually add safety gas to the tank. 6. Check the reliability of the coal feeder, ash discharger, electrical equipment, and instruments. 7. Start the ash discharge machine depending on the material level (inside the furnace). 8. Open the manual safety gas purge valve to purge the furnace through the upper nozzle; after sampling and analysis, CO ≤ 0.5%. 9. Open the viewing window and the one-way valve, and use an iron rod to check the material level and the condition of the loose layers, so as to ensure smooth startup of the furnace. 10. Close the annular tube vent valve. Boiler startup procedure: 1. Drain the condensate from the steam system, as well as the condensate in the mixer. 2. Inform the fan operator to start the fan and adjust the current to an appropriate level. 3. Open the primary valves of nozzles 1, 3, and 5 once to ensure the air supply pressure and facilitate successful primary boiling. 4. Open the valve of the oxygen-enriched air main pipe, close the vent valve of the oxygen-enriched air main pipe, and adjust the pressure using the vent valve at the same time. Air is supplied using the primary air automatic control valve, and the air supply volume should be higher than the sum of the normal primary air amount, the oxygen added, and the steam volume. 5. Once the furnace is properly fluidized, open the other three nozzles. Adjust the speed of the coal feeder as needed based on the temperature inside the furnace, increase the coal supply, and control the temperature. 6. When the lower temperature stabilizes at 850–900°C, steam is added. 7. While gradually increasing the steam, use an oxygen-enriched air blower to adjust the oxygen concentration so that the composition of the gas becomes normal. 8. When the O2 level in the gas from the gasification furnace is less than 0.2%, or when sampling at the exhaust pipe of the wet electrostatic precipitator shows an O2 level of less than 0.2%, contact the dispatch team to supply gas, inform the relevant personnel to remove the water seal and close the exhaust pipe valve. At the same time, open the outlet of the wet electrostatic precipitator, follow the established procedures, power up the system, and connect the gas to the main pipeline. Cold-start operation of the Ende powder gasifier at a certain factory – Cold-start procedures for the gasifier: 1. Preparatory work before operation: 1) Inform the operators in each position to be on site, and conduct a thorough inspection of the equipment in each position. The valves of each system are in the correct open/closed position as specified. 2) Ensure that the phone and telephone system are functional. 3) Verify the reliability of the screw coal feeder, screw ash discharger, DCS measurements, instrument interlocks, and electrical equipment. It is in closed state. 4) Ensure that there is sufficient water in the sedimentation tank; start all circulation pumps to supply circulating water to the empty spray tower, and supply combined water to the Venturi. After checking that the overflow and water pressure are normal, the valve remains in the open position. 5) Prepare for starting the induced draft fan. The valve is in the closed position. Turn on while waiting for instructions from the commander. 6) Ensure that there is sufficient amount of softened water in the softening tank; start the softening water pump to supply softened water to the degassing tank. Once the water level is normal, open the water supply valve of the degassing tank and add deoxygenated softened water to the waste boiler. Adjust the water level to the normal level by controlling the liquid level in the steam drum of the waste heat boiler. At the same time, open the circulating water valve to supply water to the three safety water seals, ensuring normal overflow. 7) After confirming that all explosion-proof panels are intact and all manholes are in order, close them. 8) Seal the U-shaped water seal properly to ensure normal overflow. 9) Through the manhole on the fourth floor of the generating furnace, dry ash with a particle size of less than 5 mm shall be spread to a depth of about 100 mm below the bottom of the lower nozzle, after which the manhole shall be sealed. 10) Open all windows of the lower nozzle, with the valve in the open position. 11) Confirm that the coal storage tank level is normal. All pneumatic valves are in the closed position. 12) Prepare a torch for ignition and wait for the ignition command. 13) Contact the instrumentation personnel to put the instruments and DCS into operation ； The electrical duty officer supplies power to the electrical equipment. 2. Ignition procedure: (1) Open the exhaust pipe valve and start the induced draft fan to maintain a slight negative pressure in the system. (2) Fill the starting gas water seal with water, and after assembling the burner, replace the gas pipeline system with safety gas. (3) After confirming that the gas composition is suitable for use, light a torch and bring it close to the burner; then slowly open the burner valve to ignite the burner. (4) After the burner has caught fire, gradually open the burner valve and observe the flame condition; once it is normal, insert them into the corresponding ignition holes on both sides of the generator. (5) During ignition, air is drawn into the generator furnace through the lower nozzle sight hole. At this stage, it is the heat storage phase of the generating furnace; the negative pressure should not be too high, as excessive pressure can easily cause the burner to go out, resulting in insufficient heat storage inside the furnace. 3. Heating operation: (1) When the temperature in the middle of the regenerative furnace reaches 700°C, (if this temperature has not been attained, the interval can be appropriately extended. ) Contact the fan operator, start the fan in accordance with the operating procedures, and control the fan current to prevent surging. Open PV113 for venting. (2) The lower nozzle FIC101 is closed, and the main controller adjusts the air supply to the furnace, gradually increasing it to create a slight negative pressure inside the furnace. (3) Open the valves of the lower nozzles 1, 3, and 5 (valves 2, 4, and 6 remain closed). The operator shall activate FIC101 to supply air into the furnace; while adjusting the amount of air entering the furnace through the lower nozzles, the coal feeder shall add coal intermittently to ensure proper fluidization of the pulverized coal. (4) Once the pulverized coal starts burning, gradually reduce the amount of gas supplied. When the temperature reaches above 800°C, the pulverized coal burns completely; at that point, cut off the starting gas, remove the two burners, close the ignition hole valves, stop the induced draft fan, and use the exhaust pipe located behind the electrostatic precipitator to discharge the gases. (5) After the pulverized coal is completely burned, the remaining three lower nozzles should be fully opened. While gradually increasing the value of FIC101, the amount of pulverized coal should be increased while monitoring the furnace temperature, in order to ensure thorough fluidization of the pulverized coal. (6) When the intermediate temperatures TI103 and TI104 reach 900°C, the waste boiler has produced qualified superheated steam. Open the manual valve of the steam pipeline for the lower nozzle, as well as the condensate discharge valve; after draining all the condensate, close the condensate discharge valve. Supply steam to the generator furnace, and the operator should gradually adjust FIC103 based on the furnace temperature. (7) When a ash layer begins to form, the screw ash discharger should be operated appropriately to loosen the ash layer and prevent slagging; when the resistance of the coal layer reaches 1000–1500 Pa, the screw ash discharger should be started to remove the ash. (8) When the temperature in the furnace reaches 900–950°C, gradually increase the steam supply while the operator at the fan station adjusts the inlet oxygen valve to control the oxygen-to-carbon ratio and ensure that the composition of the gas meets the required standards. (9) Once the oxygen content in the producer gas is ≤0.2% and the gas composition is normal, the U-shaped water seal is removed; simultaneously, the valve on the exhaust duct of the exhaust fan is closed to stop any emissions. In accordance with the procedures, the electrostatic precipitator is powered on and connected to the gas users’ systems. Conditions for emergency shutdown of the Ende powder gasifier: 1) Slagging. 2) Overtemperature. 3) The coal supply machine is faulty; it should not be able to supply coal after repair. 4) Water supply cut off to the waste boiler drum. 5) Fan trip. 6) The drum liquid level keeps dropping, and no measures can resolve the issue. 7) Power outage. 8) The microcomputer has failed and cannot be operated. 9) In the event of an emergency in the local system of a gas user, it is necessary to quickly cut off the gas supply.