I would like to ask what the purpose is of installing a separate preheating pipeline for the Texaco gasifier

During the heating-up process in GE designs, it is necessary to establish a certain level of liquid seal – that is, the overflow level of the water seal tank should be positioned between the rising pipe and the descending pipe, so as to prevent high liquid levels from blocking the descending pipe and affecting negative pressure. With a water seal tank in place, a drainage pipeline is naturally required. The slag removal method mentioned by the original poster is after all an ad-hoc approach, based on experience gained by various manufacturers through practical operations; it relies on the liquid level in the slag tank to seal the lower end of the slag discharge pipe, thereby creating a water seal

There is a reason behind designing preheating water pipelines. If only pipelines from the lockhopper or gasifier to the slag pool are used, and limestone is added to the system, the total alkalinity and total hardness of the ashwater will be high, leading to easy scaling in the black water pipelines. When the system pressure drops, the black water can only flow through the pipelines from the gasifier to the slag pool and the lockhopper. If the lockhopper valve needs to be repaired at this time, then water can only flow through the pipeline from the gasifier to the slag pool. However, as the temperature drops after the system stops operating, and due to the difference between the rate of scaling and the rate of metal expansion, the scale breaks off and blocks the pipeline from the gasifier to the slag pool. (With no pressure in the system and the lockhopper valve under repair, where does the quench water from the gasifier go?)

What to do when the slag pool is under maintenance and the furnace drying process is on schedule?

Once, when we replaced the lock slag valve, the overflow seal pipeline became clogged as well; there was no other option but to reverse the direction of the check valve at the outlet of the lock hopper circulation pump, and remove the short pipe at the pump outlet to allow drainage on-site

However, our unit doesn’t have the water seal groove that you mentioned. Our separate preheating water pipeline is connected to the black water pipeline of the gasification furnace and leads directly to the slag pool; it’s not the pipeline that carries the black water from the gasification furnace to the slag pool. However, I still don’t understand the issue of the liquid seal you mentioned!

The preheated water pipeline that we have set up separately here also leads to the slag tank. If maintenance of the slag tank is required and there is a need to accelerate the process, it is likely that the water will be directed to the actual flash tank or to the sedimentation tank.

It should be the pipeline that, as you said, bypasses the lock hopper and the gasifier black water to reach the slag pool. I didn’t know until I looked; there are so many things inside. Thank you all very much.

By the way, what exactly does this overflow seal pipeline that keeps being mentioned refer to? Is it just the rising pipe and the space around the furnace wall of the vaporizer? Or add an overflow line for the water seal tank.

The overflow seal pipeline shares the same outlet as the gasifier black water pipeline