Tail gas recovery issues in different pressure storage tanks
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During a recent conference on this topic, experts suggested that the exhaust gases from storage tanks should not be connected in parallel to a single exhaust pipe, in order to prevent backflow of exhaust gases. However, many companies currently connect the exhaust gases from their tanks in parallel to one exhaust pipe. This raises another issue: if there is a storage tank at atmospheric pressure and another at high pressure, and their exhaust pipes are connected together, won’t the exhaust gases from the high-pressure tank flow back into the atmospheric-pressure tank? Atmospheric-pressure tanks usually have breather valves, which are designed to prevent gas from entering the tank. But what pressure can the valve discs of these breather valves withstand before being damaged? I’ve also seen some manufacturers install check valves; however, the operating pressure of breather valves is very low, while the pressure drop across check valves is significant. So, after installing a check valve, will the gas pressure coming out of the atmospheric-pressure tank through the breather valve be able to pass through the check valve? Are there any other viable measures? I would like to ask all of you for your valuable opinions.
It depends on the backpressure in your pipeline network; if the backpressure is too high, cross-pressure will occur. Only through detailed calculations can this be determined.
An outlet check valve is installed to close when the back pressure rises, preventing backflow. This chain takes precedence over the regulation control for tank venting.
Is there no oil and gas recovery system? Where do the posterior collecting ducts go?
Isn’t there an exhaust fan installed on the main pipe?
There is an oil and gas recovery system, as well as a recovery device for tanks under high pressure; no exhaust fan is installed, so the exhaust gas from those high-pressure tanks can also flow into the tanks at normal pressure
This poses a danger; for example, when a vacuum distillation unit is in operation during production and another system is performing pressure filtration, an external pressure greater than 400 Pa can cause problems such as poor drainage from the vacuum distillation system, pressure buildup, and even safety incidents.