Investigation report of a chemical accident

Investigation report of a chemical accident

The official website of guangxi Zhuang Autonomous Region emergency Management Department released the Investigation Report on a Large Fire accident in Beihai LNG Co., LTD on November 2, 2020. According to the report, 7 people died, 2 people were seriously injured and the direct economic loss was 20.293 million yuan.

Immediate cause of accident

During the implementation of the second phase of the project, the isolation valve is opened, and THE LNG (liquefied natural gas) in the low-pressure external transmission manifold is ejected from the cut pipe mouth, and the mixture of the LNG atomized air mass and air generates combustion when the ignition energy is possible.

Indirect cause of accident

Improper valve isolation method, instrument engineer not according to provisions of the instrument interlock for examination and approval procedures and operating procedures, hot working conditions confirmed that inadequate, insufficient safety risk consciousness and control, “small business owners big contracting” labor production organization mode make the safe production management responsibility implementation does not reach the designated position, the contractor management does not reach the designated position, etc.

The investigation report mentioned

In the morning of that day, instrument engineer Lai Xiaolin did not execute a series of procedures such as the follow-up examination and confirmation of the instrument interlocking work ticket, but entered the engineer station and operated alone without the supervision of other instrument engineers.

At 11:44 minutes and 48 seconds, Lai Xiaolin operated the SIS system to forcibly close valve 0301-XV-2001. Immediately, valve 0301-XV-2001 was opened and the LNG began to spray. At 11:45 minutes 00 seconds, the valve is fully open. About 10 seconds after the LNG injection, a fire broke out on the platform in front of the TK-02 storage tank. There were 8 people, including Liang, on the platform in front of the TK-02 storage tank and 1 person, Including Tian, on the top of the tank when the LNG burst into flames.

The report said

In this accident, sinopec Zhongyuan Petroleum Bureau natural Gas Technology service Center, Beihai LNG Company, Sinopec Tenth Construction, Henan Hongyu, Sichuan Yitong, Sinopec Guangzhou Engineering, Qingdao Transocean have illegal and illegal situations. Among them, the Natural Gas Technical Service Center of Zhongyuan Petroleum Bureau of Sinopec violated the management regulations of instrument interlocking protection system and did not strictly implement the approval procedure of instrument interlocking according to the regulations. Instrument engineer Lai Xiaolin conducted compulsory interlocking operation before the approval of the interlocking operation ticket was completed and there was no guardian.

A group of chemical HSE experts of a certain profession specially discussed the accident. After seeing the speeches of each expert, I learned a lot. Here are the analysis and summary:
1.This accident occurred without effective isolation of dangerous energy sources. There were problems in the logic of ESD emergency shutdown system in SIS system, and the blind plate pumping failed to play a role. More importantly, do not trust the “system” too much, any system has the possibility of failure. LOTOTO(Lockout/tagout/ test) with physical linkage where possible. Confirmation and approval shall be made according to the authority and responsibility of management personnel at all levels.

2.Did not have an effective approval procedure for performing hazardous work, and did not conduct a pre-work safety assessment (JSA) prior to work. According to the strict examination and approval procedures for dangerous operations, the applicant and supervisor should strictly implement the safety assessment before the operation, and the approval should go to the site for confirmation before approval.

3.The accident investigation report seems to be very careful, and even the points and minutes are very clear: at 11:20, the side near the tank has been cut, and at 11:40, why do you urge to handle the instrument interlocking work ticket? Second, this valve should be a low liquid level cut-off valve. When and how was it closed? Not so many people did not understand the valve closed to urge the engineer to close the valve again. A lot of questions about details, but no focus, no thread. It’s hard to understand.