Comparison between slurry nitrogen process and liquid nitrogen process
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What are the differences between a process with contaminated liquid nitrogen and a process where only liquid nitrogen is used in the lower column? What are the operational differences, and does it have an impact on the extraction efficiency?
In current molecular sieve processes with high nitrogen production, there is basically no outlet for liquid nitrogen anymore~~ Moreover, pressurized expansion is used nowadays, which reduces the amount of air expanded and fed into the upper tower; therefore, there is no need to extract liquid nitrogen in order to increase the reflux ratio~~
This post was last edited by wx_I99Wh47b on 2016-6-6 at 17:52. Liquid nitrogen is referred to as 2nd PL by foreigners. In the processes I’ve seen, the ratio of 2nd PL to Air ranges from 0% to 7%. Within this range, the extraction rates of LOX and LAr increase in proportion to this ratio; the increase is more noticeable for LOX, with its extraction rate rising from 94.2% at 0% to 96.3% at 7%, while the extraction rate of LAr changes little. This can be used for fine-tuning. Of course, as the levels of LOX and LAr increase, the yield of LIN decreases
“\"2nd PL/Air at 0%-7%” – is this the amount of liquid nitrogen?
The inlet and outlet pressures and temperatures of the compressor are used to determine its polytropic index. Find the adiabatic index K of the medium to calculate the polytropic efficiency.
Yes, for example, if the air entering the tower is 100,000 Nm3/h, then 7% of that amount in the form of contaminated nitrogen, which corresponds to the 2nd PL level, is 100,000*7% = 7,000 Nm3/h