Catalytic cracking waste heat boiler
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The flue gas from our factory is exchanged heat with deaerated water in a waste heat boiler before being discharged into the chimney. The flue gas first passes through a water seal tank, but this tank isn’t in use (no water is added to it). I don’t know why the management hasn’t activated it, nor do I understand what function this water seal tank serves. In my opinion, it should be used to clean the flue gas and settle any catalysts present, with regular sewage discharge following~~~ (Is this just my personal understanding? ) But if flue gas at 500~600 degrees enters the water seal tank during use, wouldn’t that cause the water to boil violently? :o
The function of a water seal tank is similar to that of a sealing valve; it is usually used in pipelines. When needed, water is poured into the tank to block the path of smoke, as using water for sealing provides the tightest seal possible.
Once established, the water seal functions as a safety shut-off valve; it can be pushed open when the system pressure is high, but it does not serve any cleaning purpose
The flue gas entering the waste heat boiler should have a bypass line, and this bypass line should be equipped with a water seal; this water seal is filled with water normally to prevent the flue gas from taking a short circuit. There is also a water seal on the flue gas line entering the waste heat boiler, which is the water seal without water as mentioned by the original poster. If the waste heat boiler fails and needs to be taken out of service, it is first necessary to open the bypass water seal to release the water stored there, thereby clearing the bypass line. After that, water is filled into the water seal in front of the waste heat boiler to prevent smoke from entering it again. The flue gas water seal is just a special valve with no other functions.
The one upstairs is really good; our supervisor also said it’s used for sealing during the maintenance of the waste heat boiler~~~ That’s probably what it’s for: handshake. This post was last edited by tyjlovebxy on 2008-11-26 at 11:33
The poster is wrong; the water seal tank is used to cut off smoke in case of a failure, acting as a shut-off valve. During normal operation, the water seal tank mentioned by the poster is left without water and connected directly. When there is a fault in the boiler that requires repair, the water in the water seal tank on the smoke duct bypass is drained, allowing smoke to flow directly into the chimney; the original water seal tank is then filled with water to serve its purpose again.
The original poster is misunderstanding things. The water seal tank at the inlet of the waste heat boiler is used only when the boiler is shut down for maintenance, in order to prevent smoke from entering the boiler and interfering with the maintenance work. During normal operation, it functions merely as a pipe, and all that’s needed is to fill it with a small amount of water as a seal !
The water seal tank serves a sealing function; it’s like a valve. LZ should know that the valves on the flue cannot be closed.
Our spare furnace bypass line does not have a water seal tank; when there is a problem with the spare furnace, it is sufficient to open the valve on the bypass line. There are water seal tanks on the main line; they are not filled with water under normal conditions. When used as smoke ducts, only the small water seal tanks located on the outer walls of these tanks are filled with water, so that pressure can be released by allowing water to flow out when the pressure in the smoke ducts is high. Large water seal tanks are filled with water only when the remaining furnace needs repair.
The water seal tank functions like a valve; there is one at the point where the flue gas enters the waste heat boiler, and another one where the flue gas goes directly into the chimney. During normal operation, the water seal tank that leads to the chimney remains open, while the one connected to the waste heat boiler is closed. When there is a malfunction in the waste heat boiler, the water seal tank leading to the chimney is opened, and the one connected to the waste heat boiler is closed in order to prevent flue gas from entering the boiler. After the temperature drops, repairs can be carried out.
OP, how thick are your flue pipes? Think about how much it would cost to install a valve on those pipes in order to control the amount of smoke flowing through them. On the other hand, using a water seal tank is much simpler, more cost-effective, and also more efficient – water fills it up quickly, while closing the valve takes longer! The original poster, take your time to think!