How should the pressure difference of the raw material fed into the liquid nitrogen washing process and the temperature at the end face of the heat exchanger be adjusted?
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Our company’s liquid nitrogen washing unit uses liquid nitrogen washing technology provided by Hangyang; ammonia synthesis is carried out through pressurized gasification of water-coal slurry at 6.5 MPa, while desulfurization and decarburization are achieved using the low-temperature methanol washing process. During operation, the pressure difference between the raw gas entering and leaving the cold box is 1 MPa, and this value fluctuates. There is also a significant temperature difference across the end surfaces of the entire liquid nitrogen washing cold box. In particular, the temperature difference in the first raw gas heat exchanger is 120°C, while that in the second raw gas cooler is only 10°C. There is an imbalance in the cooling capacity. I would like to ask everyone how to balance the cooling capacity of the cold box, and how is the refined nitrogen and crude nitrogen allocated? The temperature of the raw gas entering the cryogenic tank is -188°C; the temperature at the outlet of the nitrogen washing tower is -195°C. The pressure difference across the nitrogen washing tower is around 15 kPa. Thank you! Thank you!
This depends on a comprehensive analysis of the process, design, and operating parameters: if the first heat exchanger is not designed to be too large, and if the levels of CH4 and trace amounts of CO2 in the feed gas are well controlled, then the pressure difference across the feed gas channel should not be that high. Try increasing the temperature of the feed gas entering the tower slightly, increase the amount of nitrogen used for washing, and reduce the internal nitrogen supply to see what effect that has.
Typical carbon dioxide freezing blockage. Take a sample before it enters the cold box and conduct an analysis
Thank you! Remove the inlet gas sample.