How to precent the pump leakage?Today let us talk together.
On April 10, 2015, the bottom centrifugal pump of the stripper in the hydrocracking unit of Dalian West Pacific Petrochemical Co., Ltd. leaked and caught fire.
A pipeline (with a diameter of 200 mm) above the bottom centrifugal pump of the tower cracked, and the oil and gas in the pipeline burned at the cracking place. The accident caused the over fire of three centrifugal pumps, the frame above the centrifugal pump, a small number of instruments and power cables, and a pipeline cracked, without damage to other equipment and casualties. The cause of the accident is: the bottom centrifugal pump of the stripper has failed to seal and the leakage is on fire.
Through the disassembly and inspection of the centrifugal pump, the bearing damage is the main cause of the rapid failure of the seal. During the high-speed operation of the centrifugal pump, due to the serious damage of the bearing and the violent vibration of the equipment, the mechanical double seal failed rapidly and simultaneously, the medium leaked, and the high temperature caused by the friction of the bearing body caused the fire. At 22:57 on April 10, 2015, through video monitoring, the operator in the main control room found that the pump area near the stripper of hydrocracking unit was on fire. It was confirmed that the centrifugal pump at the bottom of stripper was on fire due to leakage.
The unit of Sitai company released pressure in an emergency manner, cut off the valves of the inlet and outlet pipelines of the isolated stripper, and the unit operation retreated to a stable state to eliminate the possibility of further expansion of the accident. At 23:00, the fire fighting vehicles of the company arrived at the site to put out the fire and cool down. At 23:30, the fire weakened. Due to the over fire of the cable, all the cut-off valves must be closed manually. To ensure the safety of personnel and avoid secondary disasters, the open fire of the bottom pump of the tower will be put out at 1:35 on the 11th after the stripper and the bottom centrifugal pump of the tower are completely isolated to ensure the safety. In order to prevent the accumulation of combustible gas, leading to secondary accidents, fire-fighting cooling control combustion method is adopted to keep open fire at the fire point of pipeline cracking. After the oil and gas in the pipeline and its connecting device are basically burnt out, the remaining fire is completely extinguished at 4:50, and the remaining oil and gas in the pipeline and device are successfully blocked. In fact, the occurrence of the above accidents can completely analyze the relevant risks in HAZOP Analysis:
Cause: the centrifugal pump bearing is damaged and the seal fails due to vibration.
Consequence: in case of medium leakage and high temperature caused by bearing body friction, it will cause fire. In serious cases, fire and explosion will occur.
Protective measures: 1. Combustible gas alarm; 2. On site fire-fighting facilities; 3. Video monitoring; 4. Regular inspection of operation procedures and equipment.
It is precisely because of the protection measures in place that the on-site operators can deal with the accident quickly and the accident has not been further expanded.