A few questions about parking

1. Should the pressure be reduced before parking? (Do not) 2. If one of the two operating gasification furnaces plus one standby furnace comes to a stop, and the slurry tanks are matched one-to-one with the gasification furnaces, is it necessary to lower the liquid level in the slurry tanks before shutting down? (Not necessary, as there is a stirrer.) 3. Should the amount of water used for quenching be adjusted before shutting down the machine? (It is best not to make any adjustments; protecting the quenching ring is of utmost importance.) By how much and for how long should the temperature of the slag furnace be increased? (20–30 minutes is sufficient; it’s not necessary either, but be more careful when raising the temperature next time.) 4. When will the coal slurry pipeline be depressurized and cleaned? (If there are enough people, as soon as possible) 5. Is it necessary to relieve pressure from the oxygen tube? When to relieve pressure? (Do not relieve pressure to ensure safety.) 6. When is the best time to open the nitrogen plug during the shutdown sequence? What method to use? (I don’t know what it means)

1. Personally, it is best to reduce pressure and the load. 2. The liquid level can be lowered slightly. 3. It may not be necessary to lower it; a temperature of 30–50 degrees Celsius is sufficient. 20-30 minutes 4. If injecting under pressure, it should be done as soon as possible ； If not, wait until the system pressure drops. 5. It’s not necessary to release pressure; oxygen tubes can be inspected while the pressure remains. 6. It’s best to open it immediately

1. Should the pressure be reduced before parking? (Preventing pressure fluctuations after shutdown: it is advisable to reduce the load to 60% while simultaneously lowering the system pressure.) 2. If one of the two operational gasification furnaces in a three-unit setup is shut down, and the slurry tanks are paired one-to-one with the gasification furnaces, should the liquid level in the slurry tanks be reduced before shutdown? (Treat according to specific circumstances) 3. Reduce the load before stopping the machine – should the amount of water used for cooling be adjusted? (After parking, no process gas carries water, so the liquid level will rise; it is best to lower the liquid level.) By how much and for how long should the temperature of the slag furnace be increased? (50 degrees Celsius. 30 minutes) 4. When will the coal slurry pipeline be depressurized and cleaned? (Shut off the burner valve promptly to relieve pressure in the slurry pipeline.) 5. Is it necessary to relieve pressure in the oxygen pipeline? When to relieve pressure? (Protected by nitrogen plugs and oxygen-inlet/nitrogen-supply valves, operation is possible without depressurization.) 6. When is the best time to open the nitrogen plugs during the shutdown sequence? What method to use? (Agree with the opinion above)

1/ Before stopping the machine, reduce the load first, and adjust the pressure of the gasification furnace accordingly to the load level； 2/ Regardless of the number of operating units versus standby units, it is sufficient for the slurry tank level to remain stable; however, the load on the grinder must be reduced accordingly ； 3/ Generally speaking, as the load on the gasifier decreases, the amount of water used for quenching also needs to be reduced, since the thermal load on the gasifier decreases at that time; however, this is possible only if the liquid level in the gasifier remains stable ； The slag temperature is 50°C higher than the normal operating temperature, and it takes about half an hour to reach that level ； 4/ The pressure relief of the slurry pipeline should be determined based on the pressure in the gasifier; however, it is better to do this as soon as possible. This can be done when the pressure difference at PDTA18 is less than -0.5 MPa ； 5/ There is no need to depressurize the oxygen tube in a single furnace; isolated nitrogen is introduced to ensure the safety of the equipment ； 6/What does it mean?

1. Should the pressure be reduced before parking? (Preventing pressure fluctuations after shutdown: it is advisable to reduce the load to 60% while simultaneously lowering the system pressure.) 2. If one of the two operational gasification furnaces in a three-unit setup is shut down, and the slurry tanks are paired one-to-one with the gasification furnaces, should the liquid level in the slurry tanks be reduced before shutdown? (Treat according to specific circumstances) 3. Reduce the load before stopping the machine – should the amount of water used for cooling be adjusted? (After parking, no process gas carries water, so the liquid level will rise; it is best to lower the liquid level.) By how much and for how long should the temperature of the slag furnace be increased? (50 degrees Celsius. 30 minutes) 4. When will the coal slurry pipeline be depressurized and cleaned? (Shut off the burner valve promptly to relieve pressure in the slurry pipeline.) 5. Is it necessary to relieve pressure in the oxygen pipeline? When to relieve pressure? (Protected by nitrogen plugs and oxygen-inlet/nitrogen-supply valves, operation is possible without depressurization.) 6. When is the best time to open the nitrogen plugs during the shutdown sequence? What method to use? (It’s best to open it immediately.)

The amount of quench water must be reduced; otherwise, how can the liquid level in the scrubber be maintained>?

Upstairs, I agree with reducing the amount of water used for cooling, but this has nothing to do with the liquid level in the scrubber tower. The liquid level in the scrubber tower is regulated by the graywater supplied by the high-pressure ash water pump; once the desired liquid level is set, the flow rate of the graywater adjusts itself. Also, whether the liquid level in the quench chamber needs to be lowered depends on the actual conditions of the production process. In a company in Shanxi, during normal operation the liquid level in the quenching chamber was only 30%; adjusting the flow rate at the outlet of the quenching water pump often caused the pump to stop working. The solution they adopted was not to adjust the liquid level, but rather to fully open the flow control valve for the black water going to the venturi mixer right after shutdown, thereby reducing the amount of quenching water used in the gasification furnace and stabilizing the liquid level in the quenching chamber.

1. Should the pressure be reduced before parking? (Not necessary, but the load should be reduced to 60%) 2. If one of the two operating gasification furnaces in a three-unit setup is shut down, and the slurry tanks are matched one-to-one with the gasification furnaces, is it necessary to lower the liquid level in the slurry tanks before shutting down that furnace? (If parking for an extended period, it is recommended to lower the liquid level under safe conditions; otherwise it will be of little use.) 3. Should the cooling water volume be adjusted before stopping the operation? (If the load drops to 60%, it is recommended to reduce it by 30%) What should be the appropriate temperature increase of the slag furnace, and over what period of time? (According to the viscosity-temperature properties of the coal, it is generally operated at an increased temperature of 50 to 100 degrees Celsius for half an hour.) 4. When is the right time to relieve pressure and clean the coal slurry pipeline? (Within 20 minutes, depending on the situation; the sooner, the better) 5. Is it necessary to relieve pressure from the oxygen tube? When to relieve pressure? (Generally, factories do not perform this operation.) 6. When is the best time to open the nitrogen plug during the shutdown sequence? What method to use? (If the poster is referring to the nitrogen seal between the oxygen cut-off valves, it is recommended to open it immediately, without any delay.)