Air separation system's product compression system

Product compression system of air separation plant

Nitrogen penetration can meet the requirements of general compressed air. The pressure of nitrogen turbine compressor is high, and the gear type is more energy-saving.

According to the discharge pressure, there are single cylinder (low pressure) and double cylinder (high pressure cylinder and low pressure cylinder) (8-stage compression to 30bar), generally below 30barg, 5barG sealing gas is required (pressure nitrogen can meet the requirements). At the same time, due to the high pressure and high temperature fire of oxygen medium, all overflow components are made of copper alloy, and security nitrogen is required, which is generally considered by the Engineering Design Institute; The price of imported oxygen permeable membrane is relatively high, which is about twice that of domestic oxygen permeable membrane. It is generally not used. At present, oxygen permeable membrane is generally used. The discharge pressure is 3 ∽ 30barg, and the flow rate is more than 8000nm /h. However, the flow rate is small and the oxygen permeation efficiency is low, generally 8000nm /h (55%) ∽ 80000nm /h (68%).

Oxygen permeance is generally used in external compression process, ranging from 3 to 30barg. However, it is generally compared with internal compression process with booster (the efficiency is generally more than 70%, there are flow restrictions, and the efficiency is more than 10 points higher than oxygen permeance, which can even offset the advantage that external compression has less additional energy loss for reheating than internal compression, but internal compression needs to be improved for pressure discharge in steel plant to avoid fluctuation of heat exchange system). Finally, the scheme is determined.