Synthetic Ammonia Process Technology Exchange Area [Daily Question 2009-03-01]

Drive after a short stop (maintain temperature and pressure): The system does not require purging; contact the steam supply team to send steam, gradually open the steam main to warm it up, activate the backflow valve to drain any water accumulated in the pipes, start the hot water pump, and adjust the liquid level in the saturated hot water tower. 2 Start the cooling tower. 3. Contact the compression section to supply gas, open the vent valve before the saturation tower, and close it after appropriate venting. When the pressure in the inlet pipe is slightly higher than the system pressure, open the gas inlet valve of the saturation tower to pressurize the system, and slightly open the steam valve to add steam to the system. Open each drain valve simultaneously to discharge condensate, and gradually increase the steam valve opening as the system’s production load rises. The system pressure and catalyst bed temperature are adjusted using the cooling tower discharge volume. 4 Adjust the steam addition amount and the cooling water between catalyst sections based on the temperature of the catalyst bed, as well as the temperatures and gas flow rates at various points in the system. 5 Once the carbon monoxide content in the treated gas meets the specified standards, contact the carbonization unit, open the gas outlet valve of the cooling tower to supply gas, and close the vent valve of the cooling tower. Once the qualified production section is back to normal operation, contact the boiler team and the synthesis team to shut down steam supply from the boiler and switch to using steam generated by the synthesis waste boiler. 7. After receiving the notification, send hot water to the refining station.

Driving after a short stop (without maintaining temperature or pressure): After the system is purged, cleaned, tested for airtightness and leaks, and the replacement is verified to be successful, the blind flanges at the inlet and outlet of the converter are removed. 2 If the catalyst bed temperature is within the active temperature range, the startup procedure can be followed as if the system had not been overhauled, with insulation and pressure maintenance in place. 3 If the temperature of the catalyst bed is below the active temperature, the electric heater should be turned on simultaneously when gas is fed into the system; the power of the electric heater and the amount of gas vented from the condenser tower should be adjusted to control the rate of temperature increase. Once the temperature of the catalyst bed reaches the active temperature, the electric heater is turned off, and the process proceeds according to the steps for starting up the system while maintaining pressure. When the bed temperature is below the dew point, semi-water gas should be introduced to raise the temperature; once the temperature rises above 30 degrees Celsius above the dew point, high-temperature shift converters can use wet semi-water gas, while low-temperature shift converters can use medium-temperature shifted semi-water gas. Otherwise, it causes condensate to enter the catalyst bed, reducing its activity.

How to start up the transformation section system after maintenance? Answer: ① After the system has been purged, cleaned, leak-tested, and the gas replacement process has been verified to be successful, the blind flanges at the inlet and outlet of the converter are removed. ②Contact the steam supply team to send steam, gradually start up the steam for pipe warming, carry out blowdown on various equipment, start the hot water pump, and adjust the liquid level in the saturated hot water tower. ③Activate the cooling tower to supply air to the compression section; pressurize the system. Slightly open the steam valve to add steam to the system while increasing the amount of waste water removed. As the system pressure rises, adjust the valves controlling the gas flow and the amount of steam added, as well as other related parameters, based on changes in the catalyst temperature. This post was last edited by 7276166 on 2009-3-1 22:28]

How should the medium-temperature catalyst be maintained when parking? Answer: Pressure should be relieved when parking for an extended period to prevent the catalyst layer temperature from dropping below the dew point of water vapor, which would cause condensation of water and reduce the strength of the catalyst. The pressure relief rate should not be too fast and must be less than 0.2 MPa/min, in order to avoid hazards such as the fragmentation of catalyst particles, loosening of the bed layer, gas bias flow, and reduced activity. During long-term parking, the converter must be purged with inert gas, isolated from the system using blind flanges, and nitrogen must be continuously supplied to it to maintain a slightly positive pressure inside the converter.