1. Pressure and energy saving:

A. Nitrogen compressor high-purity nitrogen process: When the product nitrogen pressure is high, it is not obtained by increasing the pressure of the fractionation tower, but by first obtaining low-pressure nitrogen out of the fractionation tower, and then pressurizing it with a nitrogen compressor to obtain the product nitrogen at the required pressure . This not only improves the distillation efficiency of the fractionation tower, but also saves energy consumption.

B. Pressurized product nitrogen or positive flow air at the booster end of the expander: Use the booster end of the expander to pressurize the product nitrogen, which can not only use the booster end of the expander, but also reduce the pressure of the raw material compressor and save energy, but it has disadvantages It is the volume of the expander that changes during the production of liquid, which causes the pressure of the product nitrogen to be unstable.

　　 Two, positive flow and reflux

A. Positive flow air expansion process: Generally, the expanded air is directly expanded after being pressurized at the booster end of the expander. The expansion is close to normal pressure and directly vented. Product volume.

　　 B reflux exhaust gas expansion process: Effective use of pressurized non-product gas, divided into full expansion and partial expansion processes, full expansion produces a larger amount of liquid than partial expansion, but the expansion machine investment will increase appropriately.

Three, single tower and twin towers

　　A Single-tower rectification: Single-tower rectification is suitable for devices with a scale of less than 20000Nm³/h, and its product extraction rate is generally around 40%, and the investment is small.

　　 B double-tower rectification: The suitable device scale of double-tower rectification is above 20000Nm³/h, and the product extraction rate is generally about 60%, and the investment is relatively large.

　　 Four, room temperature and low temperature

A Room temperature nitrogen production device: The room temperature nitrogen production device is pressure swing adsorption nitrogen production, which is characterized by small scale of the device, low product purity, flexible starting and stopping of the nitrogen generator, and low energy consumption for multiple configurations of changing working conditions. Produce liquid.

　　B Low-temperature nitrogen production device: The low-temperature nitrogen production device is cryogenic nitrogen production. Its characteristics are that the equipment is generally large in scale and the product purity is high.

　　 Five, single condenser head and double condenser head

　　A Single condenser head: The condenser head is the condenser. Generally, single-column rectification is equipped with a single condenser head. The rectification efficiency of the single condenser head is average, and the product extraction rate is average.

B Double condenser head: The double condenser head is generally configured in the double-tower rectification nitrogen production device. When the condensing capacity is large, the reflux ratio of the fractionation tower will increase, and the rectification efficiency will be high. The double condenser head can effectively enhance the rectification and the product extraction rate is relatively high. high.

　　 6. With and without reboiler

A has a reboiler: the function of the reboiler is to evaporate the high boiling point gas in the bottom liquid of the tower by reboiling and rising to the gas phase. The reboiler has a strengthening effect on the rectification, which can increase the product extraction rate and increase the rectification. Circulation rate, adjust the reflux ratio, and make it to the best working condition.

　　 B without reboiler: The product extraction rate is lower than that with a reboiler.

　　 Seven, energy saving and routine

A. Energy saving: The reflux expansion process adopts full expansion, and the excess cold is taken after the expander to pump a stream of low-temperature gas and mixed with dirty nitrogen to a low temperature, and then go to the aluminum plate-fin heat exchanger to exchange heat, eliminating the need for a chiller. Invest in aluminum heat exchangers and mixers.

　　The positive flow expansion process also adopts full expansion, which reduces the pressure of the air compressor, and appropriately increases the pressure of the air compressor when liquid is produced to save energy consumption.

　　B Conventional: Reflux expansion process: not all use of exhaust gas expansion and refrigeration potential.

　　 Positive flow expansion process: Positive flow air is directly throttled and not used.