Does anyone know where the compressor anti-surge valve and the cooler should be located?
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As the title suggests, I would appreciate some guidance from those with more experience: what is the relative positioning between the anti-surge cooler and the anti-surge valve? Does it not matter who is in front and who is behind? Thank you!
I think the cooler should be at the front and the anti-surge valve at the back. Otherwise, the heat generated during the compression process by the compressor keeps returning to the inlet, causing the temperature of the medium at the compressor inlet to rise continuously. The anti-surge valve gradually opens wider until it is fully open, after which the system experiences surge. The cooler is used to make the compression in a centrifugal compressor as close to isothermal compression as possible, thereby saving compression work; it is not intended solely to prevent surge.
The cooler and the anti-surge valve in the compressor unit each serve their own purpose； During the compression process, when the gas reaches a certain temperature, in order to reduce the power consumption of the compressor, the hot gas is drawn out of the compressor to be cooled, and then fed back into the compressor for further compression ； The purpose of the anti-surge valve is to prevent surge in the unit when the compressor operates at low flow rates. Therefore, a cooler is installed in each section of the compressor, but an anti-surge valve is not necessarily present ； The anti-surge valve is simply installed between the cylinders or sections as required, depending on the characteristics of the unit ； When the gas delivered by the compressor cannot be discharged into the atmosphere, a cooler and an anti-surge valve must both be installed in the anti-surge circuit to ensure that the cooled gas returns to the compressor system; generally, a cooler is placed first at the compressor outlet, with the anti-surge valve following it. When the gas delivered by the compressor can be discharged into the atmosphere, a surge control valve is generally installed only in the surge protection circuit, with the gas behind the valve being directly released into the atmosphere. Such as air compressors
Generally, a cooler is installed first, followed by an anti-surge valve; this allows the selection parameters for the valve to be reduced appropriately, thereby saving costs.
Reply to 2# lshx888: Thank you, but can the gas be cooled either in front of or behind the cooler’s relief valve?
Reply to 4# sevfor: Thank you! If the valve is placed before the cooler, although the cost of the valve decreases, the cost of the cooler increases due to high pressure. If the cooler is equipped with a relief valve, I think the reduction in the cost of the cooler will be greater than the increase in cost due to the valve, but I’m not sure if it will have any impact on pipeline vibration or anything similar
Reply to 3# srita: Thank you for your explanation. But if the cooler is at the back, it can also achieve the purpose of cooling the gas. What are the advantages and disadvantages of this compared to before the cooler relief valve was opened?
Reply to 6# bellexw: From the perspective of the entire process, it’s better to have the cooler at the front. Take the ammonia refrigeration process as an example; it is a closed-loop system. Ammonia is pressurized and heated by a compressor; after passing through the cooler, the process pipeline splits into two branches. One branch passes through a condenser again to be converted into liquid ammonia, which then enters the liquid ammonia storage tank, while the other branch is used for anti-surge protection. Due to the different types of compressors, such as three-stage compressors, the anti-surge protection circuits are divided into three branches, with a set of anti-surge valves in each branch that open back to the inlet of their respective stage. The advantage of this design is that one cooler is sufficient to meet the requirements of the entire process. If a surge valve is installed first and then a cooler follows, then first, the line for converting liquid ammonia must be placed before the surge valve; this requires a separate cooler to be provided for it ； Secondly, on each anti-surge circuit, a separate cooler must be installed behind the anti-surge valve; as a result, the costs associated with additional equipment and piping layout will **increase**. I’m not sure if this example will be useful to you.
Original poster, look here – I’ll give you the correct answer! ! The sequence of the main pipeline at the compressor outlet is: outlet -- cooler -- followed by a surge valve, a vent valve, a main pipeline control valve, and a shut-off valve. Why put it behind the cooler? Saved a cooler! ! If a surge valve is placed in front of the cooler, then the cooler in the main pipeline cannot be removed; an additional cooler will have to be added to the surge prevention pipeline as well. Place in the front = 2 coolers, place at the back = 1 cooler!
Reply to 8# sevfor Thank you! What you’re saying about this situation makes sense. But what if there are two surge circuits with different gas compositions, each requiring its own cooler? Why can’t the cooler valve be opened in this situation? In this way, the total cost of the cooler and valves will be lower. . .
Reply to 9# Lazy Sheep: Thank you for your reply! If there is no main line cooler, there are two anti-surge circuits, each requiring its own cooler. In this case, can the cooler be placed after the valve?