Approaches for modifying high flash point in water-coal slurry gasification

Does the wear mentioned by the poster refer to the high-flash inlet?

Wear in flash vaporization systems has been a problem since the inception of water-coal slurry gasification. The solutions available include changing the installation angle of the angle valves or using wear-resistant materials; other methods involve using control valves to reduce pressure step by step. There is no better solution, and practice has shown that optimizing operations is the best way to reduce wear.

It is understood that there are two such modification methods in practice: 1. Change the elbow behind the corner valve to a tee； 2. Replace the elbow pipe behind the angle valve with an expanded pipe. The effects of these two methods are quite noticeable in actual operation. Regarding the issue of ash accumulation due to flashing, the elbow in the black water pipeline at the bottom of the high flash vessel can be replaced with a tee; two high-pressure valves should be installed in the straight sections of the pipeline, which lead to the sewage tank. During normal operation, discharge should take place periodically to prevent ash from accumulating inside the equipment. When the system is shut down, the black water can be discharged from this location under slight pressure, thereby preventing sludge from remaining inside the high flash vessel after shutdown.

Regarding the issue of high steam causing ash buildup, please share your ideas on how to address it

Yes, do you have any good ideas?

What you’re saying is too general; it’s impossible to solve the problem based on that. Could you be more specific?

Your approach is quite reasonable, but you still haven’t addressed the issue of ash being carried in the flash vapor.

Your approach is quite reasonable, but you still haven’t addressed the issue of ash being carried in the flash vapor.

Many posts on these forums have discussed these issues countless times; I’ve gathered them together to see what solutions exist. As for the problem of high flash point accompanied by ash formation that you mentioned, I haven’t encountered it, as the quality of coal varies from one manufacturer to another, and the control of gasification temperature also differs. Additionally, adjustments to the amount of oxygen used have different effects on the composition of the syngas as well as on the amount of fly ash produced. I have been working as a supervisor for water-coal slurry gasification for 12 years, and I have never faced the issue of high flash point with ash formation that you described. For some problems, one can only suggest approaches; there is no way to apply fixed solutions directly.

I don’t think it’s as complicated as you say. I’m already making changes on my end; I just want to hear everyone’s opinions.