Various accidents that have occurred in sulfur plants over the past few years
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From personal experience, I went straight to the sulfur processing workshop right after graduating to work as an operator. Our workshop was newly established, and the skill level of the operators there was quite poor. Below are the accidents that have occurred over the years; such things might be seen as laughable in other companies, but as someone who has been through this, I feel it’s necessary to leave some record of these years of growth. 1. When we first arrived at the sulfur processing workshop, our sulfur sealing device was a large tank located underground, with 5 sulfur discharge ports extending to the bottom of the tank. During one start-up, one of the liquid sulfur pipelines was put into use too early without sulfur being removed, which caused a large amount of black slag (rust) to clog the pipeline. By the time it was discovered, the system pressure had already risen – what should be done? We closed all the valves of the liquid sulfur pipelines that lead to the sulfur sealers, used buckets to collect the sulfur, and then poured it into the flow cell. At that time, the company assigned over 10 people from various workshops to specialize in using buckets to collect and pour sulfur. All the sulfur inside the sulfur sealer was scooped out using buckets; the jacket heating was turned off. At the bottom of the sulfur sealer, there was 20 centimeters of hard black residue, which had to be broken up using a pneumatic hammer. Finally, the pipelines connected to the sulfur sealer were removed and heated with fire. Install! It was a dark time; at work we dealt with sulfur, and it was extremely smoky.
2. Fire accident in the middle section of the sulfur production furnace! I guess there aren’t many sulfur production furnaces that catch fire across the country either~! And that’s how we got caught! The specific issue is that our device is small in scale, which results in a high volume of data that it cannot handle. . . The leader saw that there was still the central acidic gas line after all. . . I’ve never used it before either. I looked it up online, and it seems to be quite good! (Previously, don’t discuss the air distribution ratio; there was no online monitoring, hydrogen addition wasn’t activated, and when the furnace head temperature couldn’t be reached, we simply increased the air supply.) Then it was put into use, and it turned out to be quite good. . . . . Two days later, at night, an acid gas line in the central area leaked and caught fire; there was positive pressure inside, causing the flames to shoot out up to 5 meters away. Fortunately, there were no facilities in the vicinity. It was immediately removed at that time. In the end, it was found that there was no problem with the sulfur production furnace; instead, the elbow in the acidic gas line had been burned through. The short-circuiting component was removed, and the elbow was replaced overnight. It was thrown again. Upon further investigation, the reasons were: the activation of the central acidic gas line and the activation of the backflow ventilation system. Fluctuations in acidic gas led to backflow, which then caused burning through. . . That’s why ignorance can be deadly sometimes. . . It’s a simple principle, but due to insufficient theoretical knowledge, in new workshops, it seems safer to have wind blowing in. Tragic!
3. Do not drain the remaining water in the pot! This one is even more embarrassing to talk about. . . At that time, sulfur production had just started, there were not many employees, and there was no market for liquid sulfur. Sell sulfur fixation agents. This version is also fine; the problem is that our molding equipment is of poor quality and breaks down frequently, which means that employees and managers spend most of their time fixing it. A few months passed (I can’t remember the exact time), and I noticed that the heat exchange in the remaining boiler wasn’t working well.... How is that possible? It’s a new installation, new equipment – how could the heat exchange function poorly? Contact the Equipment Department to find out the reason. . . . The final result was that the residual pot was never cleaned of its dirt. Damn, I’ve never cleaned the residual pot. . . . At that moment, I was stunned. Why did the surplus pot need to discharge waste? Why didn’t anyone tell me this?! ! ! The final treatment involved a residual pot with a value of 1.0; this was reduced to 0.4, until maintenance and treatment were carried out half a year later. Ignorance, ignorance, ignorance! !
There’s still work to be done; I’ll update it whenever I have time, discussing the problems that have arisen over the years and so on. I hope the users of Haichuan won’t laugh at us, and I also hope that Chinese chemical companies will become more mature and experience fewer accidents. Whenever I hear news online about explosions or fires somewhere, I feel sad for some reason; there are always such sad moments on China’s path of development!
This post was last edited by ylb913 on 2016-3-15 09:58. We have each experienced the first two situations mentioned by the original poster once. But the severity seems to be lower. Due to a blockage in the liquid sulfur pipeline, we had to carry the sulfur up bucket by bucket; the total amount was about 3 tons. This was done by the workshop staff themselves. Then, we turned off the heat tracing, cooled the area with water from outside, and introduced industrial air. Workers went down to the site and chiseled out a hole at one of the outlets. After that, we drained the water outside the tank and reactivated the heat tracing... One of our units for handling acidic gases in furnaces has been in use for 10 years, and it has always utilized reverse blowing. This time, we installed a larger sulfur-handling unit. Initially, both units were supposed to operate in parallel for a week. However, just a few hours after startup, the elbow joint in the new unit’s furnace section where the acidic gases flowed through got burned through. As a result, all the acidic gases were redirected back to the original unit; the elbow joint was replaced, and operations resumed. Reverse blowing in the furnace was switched to nitrogen instead. Additionally, operational measures were taken: the flow rate at the acidic gas inlet valve in front of the furnace was restricted, and pressure was increased to prevent any interruption in the flow of acidic gases within the furnace.
Actually, when the acidic gas in the middle section is in use, there is no need to use backflow; we only employ backflow when it is not in use. There is also backblowing nitrogen, but it has never been used! It’s been several years now; it’s not in use, and that’s normal! The three elements of combustion: without wind, there is no combustion~!
1. What is the purpose of backwashing? Isn’t it to prevent blockages at the pipe outlets due to a sudden interruption in the supply of acidic gases? In 1998, when I was learning * at another factory, the acidic gas line in their furnace wasn’t working. 2. The acid gas flow control valve of our new sulfur unit is located before the diversion into the furnace, which results in too low a pressure downstream of the valve; as a result, there is no force to divert the gas into the furnace. Therefore, we are forced to use the manual valve in front of the furnace, and our furnace also has a flow control valve.
4. Frequent backwashing of the rich liquid filter. Previously, after backwashing our rich liquid filters, the liquid was discharged directly into the drain ditch, the sewage ditch (in the pump area). One night while on shift, I suddenly heard over the intercom that the rich liquid filter was being backwashed, and the flash tank immediately ran out of liquid. . . I ran over to check and found that the rich solvent filter kept undergoing backwashing—constantly switching between backwash cycles. The drainage in the ditch was slow, and the amine solution started to overflow. . . At that time, an experienced technician immediately turned on the auxiliary line, and everything returned to normal. Later, calculations showed that some amine solution was lost, but this did not have a significant impact on subsequent operations. Later, modifications were made to redirect the waste discharge from the rich liquid filter to an underground storage tank.
5. Frequent backwashing of the regeneration tower. After half a year of operation, our regeneration tower finally stopped working properly. . . Start frequent backwashing. The specific reason is unknown; it won’t happen. According to what I found, it’s caused by foaming in the lean liquid; adding an antifoaming agent to the lean liquid tank doesn’t seem to work very well either. Because the surge is very strong, it rushes directly into the buffer tank, carrying with it most of the lean liquid. The liquid level in the lean liquid storage tank drops rapidly. To the best of my memory, the worst incident involving fluid surging occurred when the acid gas buffer tank was filled to capacity, causing the amine solution to flow into the sulfur production furnace. . . It almost caused the engine to stall. The final solution was simple: the lean liquid filter was put into use. . . .
6. Turning the shaft is very important. It’s been about half a year since the new equipment started operating. One day, the manager had an idea and said we should switch the sulfur production blowers. Upon arrival, it was found that the backup fan’s crank could not be turned. . . It’s been about half a year; the staff didn’t realize that the backup pump still needed to be turned by hand. It’s really unbelievable. Finally, a blacksmith was called to remove it and apply grease. . Solution: Perform regular operations; each shift should crank the engine at least twice. . .
7. Install a check valve at the outlet of the sulfur production blower. This should be very necessary. At the time when our equipment was started up, this wasn’t present; it seemed to be a power fluctuation, and the fan stopped. . Then halt operations urgently~~! As a result, the outlet control valve of the fan could not be closed properly, causing a large amount of flue gas from the sulfur production furnace to flow back through the fan. The personnel on duty were quick enough to react, so no injuries occurred. This left a deep impression on me. Two days later, we installed a check valve with welding. So, after working with sulfur for a few years, I learned that one shouldn’t rely on butterfly valves to close tightly; it’s really necessary to have an extra safety measure!