Cavitation problem in quench water pumps for water-coal slurry gasification
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In water-coal slurry gasification, a quench water pump is used to pressurize the liquid at the top of the scrubber tower and feed it into the quench ring of the gasifier, where it serves as cooling water for the quench ring as well as for washing and cooling in the quench chamber. Since cooling water pumps are generally designed as cascade pumps, with an inlet and outlet pressure difference of around 15 kilograms, and the temperature of the fluid being transported is very high, this makes cavitation in such pumps more likely to occur. The risk of cavitation is especially high during the start-up and shutdown processes of the gasification furnace. What good suggestions do everyone have to avoid this problem?
Hasn’t everyone encountered such a problem?
Raise the system pressure as soon as possible; it’s sufficient if the pressure is higher than the saturated vapor pressure of water at the corresponding temperature.
When the gasifier is shut down, the system pressure can be controlled at will, which makes it easy to avoid this issue. If parking time is limited, for example in the case of continuous operation, it is also possible to rapidly cool down by supplying deoxygenated water to the pump inlet for an extended period of time. But if there is no pressure in the system while the machine is running, and the water circulates and gets heated in the cooling jacket and downcomer, the water temperature in the system rises rapidly; as a result, cavitation can easily occur before the vaporizer starts operating. I wonder if other companies have encountered this issue?
There are two approaches: cooling down and increasing pressure. . Cooling down means adding water for parking. Boost it up, installation height? Dig a hole and try installing the pump; P
A high-pressure ash water pipeline can be led to the inlet of the quench water pump
I’ve really never encountered this while driving
Cavitation has not occurred when parking. It happens easily when driving. In recent years we have been using accident cooling water for driving; after driving and experiencing pressure, turning on the cooling water pump prevents cavitation
Try to maintain a balance between the temperature of the quench water and the pressure of the system
The selection of the pump and the material of the impeller are very important! ! ! Cavitation in chilled water pumps is inevitable! !
We use high-pressure gray water for feeding while driving, and then start the chilled water pump after lifting.