Incidents of spontaneous combustion of ferrous sulfide during maintenance collected
Thread Content
Case 1: On April 25, 2004, a catalytic unit came to a complete stop due to a failure in the power supply system, and the shutdown was carried out following emergency shutdown procedures. Due to the shutdown of the blower, the furnace in the acidic water stripping system went out of operation. The operators promptly cut off the gas supply, and the remaining gas in the stripping tower was discharged through the furnace’s chimney. Approximately 4–5 hours after the shutdown, thick smoke was observed coming from the furnace’s exhaust chimney, and monitoring instruments showed a sharp rise in the temperature of the flue. The plant operators immediately closed the valve at the inlet of the acidic gas furnace and introduced temporary steam into the furnace for purging ； Thanks to timely detection and proper handling, which prevented further escalation of the incident, subsequent inspections revealed severe deformation in the carbon steel chimney at a height of 10 meters above the ground. Case 2: On May 2, 2001, during maintenance work in the catalysis unit of a petrochemical plant, the distillation system was purged and the equipment was opened for venting. At 2 p.m. the next day, thick smoke was observed coming from the manhole of the oil-gas separator at the top of the fractionation tower; shortly thereafter, a flash explosion occurred, accompanied by an irritating odor, which was identified as sulfur dioxide gas. The workers in the workshop immediately poured water into that tank to cool it down, thereby preventing the situation from worsening and avoiding significant losses. I wonder how things are at your workplaces, brothers: Q
If the deodorization tank located on top of the hot and cold coke water tanks in a coking plant is not properly controlled, it can also catch fire spontaneously!
The acidic water tank (catalytic), during demolition, caught fire on its bottom 3 days later due to the release of water.
It is mainly the spontaneous combustion of FeS. Many current oil refining plants use crude oil with high sulfur content, which increases corrosion of the equipment. When the equipment stops operating, without nitrogen purging or steam cleaning, it comes into contact with oxygen in the air and catches fire on its own, causing damage to the equipment
The unit was shut down for maintenance; due to the failure to carry out cleaning and passivation treatments using ferrous sulfide, ferrous sulfide on the foam breaker mesh caught fire spontaneously. Lesson: After the plant is shut down, the containers and equipment containing ferrous sulfide that need to be opened must be cleaned and passivated to prevent spontaneous combustion of ferrous sulfide and damage to the equipment!
Last year, during the shutdown for maintenance of our catalytic unit, passivation treatment was applied to the ferrous sulfide areas, and the result was excellent – no spontaneous combustion occurred.