Startups and shutdowns are relatively risky for process production devices at refineries or chemical plants. According to the CCPS, process safety incidents occur five times more often during driving than during normal operations, although plant start-up operations make up only a small part of the overall plant operation.
In 2010, an accident of oil refining industry, the study found 50% of process safety accident happened in the first drive, open parking, parking driving, again after a short time for a long time driving such as stage, after this is because the process involves many irregular open parking time period, and such period may lead to unexpected and unusual situations. Although the enterprise has also taken some safety measures in these stages, because the safety layer is mostly in the bypass and so on can not play a functional state, these stages are actually the disaster areas.
In order to prevent the occurrence of similar major process safety accidents, the factory shall formulate strict and up-to-date operating procedures and emergency plans for production devices, provide appropriate training for operators and conduct effective communication. In this issue, we share eleven key principles and best practices for process plant safety management.
The following are three safety incidents reported by the U.S. chemical safety commission (CSB) during parking operations and lessons learned to prevent similar incidents in the future:
1/02:40 on March 13, 2001, a BP Amoco Polymers, NC corporation emergency tank in Augusta, Georgia, caused a thermal breakdown overpressure explosion that killed three people.
At the time of the accident, three workers were trying to open the end cover of a hot-melt plastic process tank, a polymer collection tank designed to recycle some of the waste plastics that have been partially reactivated in its chemical reactors during driving and parking. The workers were killed when a partially bolted end cap burst and spewed molten plastic. The jet's energy caused a nearby pipeline to burst, igniting the hot liquid flowing from the pipeline, which then formed a vapor cloud and ignited.
The CSB investigation found that 12 hours before the accident, the workers tried to start the car, which was stopped due to some malfunction of the extruder downstream of the reactor, and a large amount of raw material that was not fully reacted was sent into the polymer recovery tank. The hot and molten plastic continues to undergo a chemical reaction in the polymer recovery tank and begins to decompose, creating a gas that causes the polymer to bubble and swell in the tank, eventually filling the entire tank. The pressure of expansion presses the polymer down on the pipelines connected to the tank, including normal and emergency discharge pipelines. Once inside the pipe, the plastic solidifies as it cools and blocks the pipe's entrance. The inability of the gas in the pipeline to escape resulted in pressurization of the polymer storage tank. CSB also found that BP Amocro's process hazard analysis (PHA) and process safety information about the design basis and operating principles of the polymer storage tank were inadequate.