How should an emergency shutdown be carried out in a urea plant in the event of a carbon dioxide gas outage?

This post was last edited by Xieshui on 2010-3-3 at 18:28. The so-called CO2 interruption occurs in two scenarios: either there is no CO2 available upstream, or the reciprocating compressor (the large centrifugal unit) fails and shuts down. In such cases, emergency shutdown procedures must be followed as per the regulations. Since CO2 supply is interrupted, it is important to: 1. prevent backflow of liquid into the synthesis tower, and 2. prevent backflow of liquid from the stripping tower into the CO2 pipelines. Each plant has established emergency response plans for CO2 interruptions.

The inlet flow rate of the CO2 compression unit is one of the main causes of surge in the unit. In the event of a CO2 supply interruption, anti-surge measures for the unit must be taken immediately; if necessary, the unit should have its load reduced or it should be shut down. In the event of an emergency shutdown of the process system: 1. It is necessary to contact the dispatch team promptly in order to adjust the steam supply to the steam and water treatment plant, thereby preventing overpressure in the high-pressure steam system and avoiding situations where the boiler could be damaged. 2. The tower should be sealed during the system shutdown, in accordance with the procedures specified in the operating guidelines. 3. When parking, the isolation valve on the pipeline from the CO2 compressor to the stripping tower should be closed promptly to prevent a large amount of methylammonium solution from flowing back, and this should be verified on site. 4. Prevent backflow of liquid