The significance of replacing burners in the gasification furnace and its impact on subsequent processes
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Does anyone know whether restarting the gasifier after replacing the burner during a shutdown, or starting it up again after normal maintenance or repairs, is more beneficial for its long-term operation? There was once a manufacturer whose gasifier operated for over 500 days, setting a world record for the longest operating time. But what impact does such long operation have on the lifespan of the gasifier’s bricks? And does it contribute to stable production? Based on our company’s operational records, when the furnace operates for extended periods of time, the maintenance required is longer, and various problems arise, such as severe erosion of the furnace bricks, overheating of the furnace walls, and scaling in the equipment pipelines. In my opinion, prolonged operation poses certain risks to the stable production process. What are your thoughts?
I have been working in water-coal slurry gasification for 13 years; I am the fifth person in the country to be in charge of this technology. I have never heard of a case where water-coal slurry gasification operated for over 500 days without interruption. If someone tells you that it has operated that long, tell them they are lying.
I started working in water-coal slurry gasification in 2003, under the guidance of Wang Xubin from Shanghai Coking. Our plant began operating for water-coal slurry gasification in June 2004, making us the fifth plant of its kind in the country. Our factory is Haolianghe Fertilizer Plant in Heilongjiang Province, and I was the first person in charge of gasification there. Back then, it wasn’t like now when we could hire expert teams to operate the plants; we also tried to do that by reaching out to Shanghai Coking, but their team said they didn’t have time. At that time, Huaihua Fertilizer Plant in Anhui had been in operation for less than two years, and when we asked them for help, they said they lacked experience. Weihe Fertilizer Plant and Lunan Fertilizer Plant didn’t even consider helping us – we didn’t even get a chance to discuss things with them. Our own team received 50 days of training at Shanghai Coking, and after returning, we managed to operate the plant successfully on our own. It was really not easy back then.
It’s not a single batch of material; currently, the material used for the burners is not capable of withstanding such long operating times. They have replaced the burners over time and continued to use them, but it’s already quite good that they can operate continuously for such a long period.
By 500 days of continuous operation, he meant the entire system, achieved through backup boilers, not a single boiler. I remember it seems like Thorpe was running continuously for 511 days.
The maximum operating time for a single furnace in multi-nozzle gasification is 150 days, a record set by Lunan Chemical; the normal operating time for such a furnace is 120 days； The maximum operating time for a single nozzle is also around 250 days for the gasifiers in Lunan. There are many people from Lunan on the forum; could you provide the specific time? The so-called 511 days indeed does not refer to the time per furnace; there are standby furnaces, and I am the supervisor of this setup. The promotional materials mention coal chemical plants; some misleading materials claim that the gasification furnace operated continuously for 511 days, which I find amusing as well. Under normal circumstances, we perform furnace turnover every 75 days; the burners operate for at most 110 days at most (in cases where a backup furnace is not available). I think whether a unit operates stably depends on the execution of planned start-up and shutdown procedures. In my opinion, although long-term implementation can yield significant benefits, the difficulties involved are immense; dealing with faults online on multiple occasions, and any mistake in the planning or execution stages can lead to accidents. When the gasification furnace has no level indicator or temperature indicator for two full months, the composition of the syngas fluctuates frequently, and the ash melting point of the coal can vary by up to 200°C – who would think that 511 days is a simple period of time? Those who drove during the same period as us have a record of 192 days of continuous operation. . . I think while efficiency is important, safety cannot be ignored either; stable and safe operation is what we strive for. Long period? I laughed when a plant used excessive pulverized coal in order to keep operating with a single burner over a long period of time. For such a mere illusion of success, ignoring efficiency and disregarding safety – what’s the point of such a long operation period?
Yes, the risks associated with long-term operation are quite high. The conditions in gas chemical plants are poor, and various forms of corrosion – especially abrasion – are severe. In many cases, it is necessary to carry out repairs while the system is still under pressure. Here, we have encountered multiple instances of leaks in the packing of the drainage valves in the gasification furnaces, as well as sand holes in high-flash-point and high-pressure pipelines. In such situations, it is impossible to shut down the system for repairs. Moreover, due to the high temperatures, it is not possible to measure the wall thickness of these pipelines, making the repair process extremely dangerous. But I wonder why many factories still prefer to keep the gasification furnaces running for long periods – what is the advantage of doing this for the whole system? I wonder if this represents the future trend in gasification operations – whether it is aimed at accumulating experience and parameters over time as gasifiers operate for extended periods, so as to guide optimized operations.
Additional note: When communicating with many manufacturers, it’s inevitable to ask about the maximum operating time of the gasification furnace.
It is safer to plan a furnace change if there is a spare furnace available. If there is no backup furnace, it is necessary to accumulate as much data as possible under conditions of technical reliability, and to operate for as long as safe to do so; over time, experience-based data will be available. This is just my personal opinion.
You’re absolutely right, but I want to know what the standards and timing for furnace conversion are. Is it necessary to carry out gasification-based furnace conversion when everything is working normally? It’s understandable to do so in cases of abnormal situations that cannot be resolved during operation. However, if the decision is based on the operating records of other manufacturers or on the lifespan of burners, I don’t think we should always let past experiences dictate our current procedures. Progress comes from continuous innovation, and every action involves risks; sometimes we need to take action because the potential benefits outweigh the risks. Competition in the chemical products sector is becoming increasingly fierce, so it is essential to reduce costs. If risks can be kept within acceptable levels, I think it’s worth giving it a try. Operating the gasification furnace for extended periods certainly saves costs compared to regular shutdowns for maintenance; however, it’s necessary to calculate exactly how much this savings amounts to. After all, this is a good example of a lean initiative.
Those upstairs are all at an expert level; they’ve mastered it. The longer it goes on, the more terrified I become.