Measures to prevent materials from flowing back into steam pipes
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Dear experts, our company produces by-product steam, and all the steam within the company is usually supplied by the by-product steam. The homogenization pool and anaerobic pool of our company's sewage station must maintain the temperature of the wastewater at 20 degrees due to bacterial environment reasons. The design has steam pipes leading to the homogenization pool and anaerobic pool. Problems encountered: When all the equipment is stopped, the steam supply is cut off. After the steam is condensed, a slight negative pressure may be generated. The water level in the anaerobic tank may also be higher than the height of the pipe gallery. Due to reasons such as insufficient handover or forgetting to close the valve at the sewage station station, our company once shut down, and the sewage in the anaerobic tank flowed back into the steam pipe network, polluting the steam pipe network. Solutions: I would like to ask you all, apart from installing check valves before and after the steam valve, is there any other way to technically solve the problem of technical modifications or measures to prevent sewage from flowing back to the steam pipe when the valve is forgotten to close?
An inverted U-shaped bend is installed behind the valve. The height is 10m higher than the maximum liquid level of the homogenization tank and anaerobic tank, which can effectively prevent backflow.
Install a quick closing valve and control it with a solenoid valve
There are relevant chapters in the chemical process design manual, which mainly use the principle of vacuum breaking.
1. Calculate the pipeline volume. Add buffer tank and check valve. Even if it flows back, it flows back into the buffer tank. ； 2. Add an automatic continuous device to detect the pressure of the front-end steam, set a critical value, and automatically close the valve.
The steam here actually has two pipelines with different pressures, one is 0.3MPa, and the other is 1.4MPa, which can be switched. If you use the principle of breaking the vacuum as you said, it is generally sealed with water. If it is used here, it is probably not suitable. Water seal vacuum breaking is generally used in storage tanks with slight positive pressure or normal pressure.