Anti-negative pressure measures for the suction pipeline of combustible gas compressors
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Article 4.6.8 of the Code for Fire Protection Design of Petrochemical Enterprises: The suction pipeline of combustible gas compressors shall be equipped with measures to prevent the formation of negative pressure. May I ask what measures are taken to prevent negative pressure from occurring? I would be extremely grateful if all of you experts could kindly offer your guidance
A bypass with pressure regulation can be provided to prevent negative pressure from forming at the compressor inlet.
Bypass with pressure regulation? How is it specifically set up? Could you provide a diagram explanation? Thank you!
For media that are gaseous at room temperature, usually a pressure gauge together with a gas pipe connecting it to the large tank is sufficient. The valve at the root should remain open. If the medium tends to condense at room temperature, insulation, heating, and condensate drainage are required. Of course, a pressure gauge is also necessary.
It is possible to set up a circulation circuit for the compressor, or what is known as an anti-knockback circuit, and to install an alarm interlock on the inlet pipe; an alarm is issued first, and once the pressure drops below a certain value, the anti-knockback valve opens, ensuring that the inlet pressure of the combustible gas compressor remains within a safe range.
A bypass pneumatic valve is installed between the compressor outlet and inlet, with its opening degree being controlled automatically. A pressure transmitter is placed at the inlet, and a specific pressure range is set for it; the signal from this transmitter is used to control the opening and closing of the pneumatic valve as well as its degree of opening. When the pressure at the inlet drops to a certain value, the bypass pneumatic valve opens, allowing high-pressure gas from the outlet to flow into the inlet. Once the inlet pressure reaches the set value, the pneumatic valve closes. This process repeats continuously.
1: Set the pressure control valve to return the gas from the compressor outlet to the inlet or to a high-pressure flare. 1: Install a compressor suction flow control valve, so that the gas exiting is returned to the inlet. 3: Set the pressure control valve to supply nitrogen when the suction pressure is low.
Can the compressor inlet pressure operate at a minimum negative pressure during continuous operation? For example, -4500 Pa.
A reflux bypass circuit is established, allowing a portion of the gas at the outlet of the centrifugal compressor to flow back to the compressor inlet after passing through a cooler. This increases the flow rate at the compressor inlet and reduces the likelihood of surge occurring. When designing process pipelines, the capacity of the compressor outlet piping and return piping should be minimized according to actual needs (including reducing the pipe diameter and length). Because the larger the capacity of the pipeline, the greater the amplitude and lower the frequency of oscillation; the smaller the capacity of the pipeline, the smaller the amplitude and higher the frequency of oscillation.
I don’t know much about this topic; I suggest the original poster check out the answers from other users above. I’m also learning about it