Synthetic Ammonia Process Technology Exchange Area [Daily Question 2009-03-18]
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Synthetic Ammonia Process Technology Exchange Area [Daily Question 2009-03-18] What are the reasons for overpressure in the fourth stage of the compressor?
There is a problem with the valve or piston rings in section 5, or the pipes are blocked. Alternatively, the amount of air returning to the balance chambers in sections 6 and 7 is too high.
Regarding the compressor itself, there might be a leak in the air valves, and it’s also possible that there is an internal leak in the 6-to-4 mechanism. If there is overpressure and the trace level is also high, then the issue of three-or-four-way direct connection needs to be considered.
The compressor process design is based on the properties of pure gases. At (absolute) zero, gases, just like hydrogen, nitrogen, and air, obey the ideal gas law; however, as pressure increases, the volume of some gases decreases more rapidly than that of an ideal gas. Therefore, there is an overpressure issue in sections 3 and 4; to resolve the overpressure problem in section 4, the method of enlarging the cylinder body of section 5 can be adopted. The northern plant reduces the cooling temperature of the gas at the fourth stage outlet (from the originally designed value of °C to °C) in order to reduce the gas volume and lower the pressure ； The high water temperature in the south allows for an increase in the area of the four-stage cooler. As the gas purity decreases, the overpressure at the outlets of stages 3 and 4 becomes more severe, especially with a faster increase in the pressure at the outlet of stage 4.
1. Check carefully whether the five-stage gas valve is damaged. Are 2 four-stroke cylinders and four cooling water outlets sufficient? Or the heat exchange efficiency deteriorates. 3. Whether the piston rings are leaking. 4. Check whether the opening degree of the four-way valve is appropriate or if the valve head has fallen off.
1. Check whether the four piston rings are severely worn, which could lead to an increase in the cylinder clearance and thus cause overpressure at stage 3. 2. Check whether the intake and exhaust valves at stage 4 are damaged or not closing properly, as this could also result in an increased cylinder clearance and overpressure at stage 3. 3. The exhaust temperature might also be a factor involved.
Inspect the five-stage piston rings and the four-stage cooling system