Process for maximizing the recovery of argon from an air separation system at high argon recovery rates.

摘要

Process for maximising the recovery of argon at high argon recovery rates from an air sepn. system having a high and low pressure distn. column contg. multiple distn. stages of rectification with the high pressure column providing a nitrogen rich reflux fluid to wash the rising vapours in the low pressure distn. column and having a separate sidearm column for argon recovery, comprises (a) introducing an oxygen enriched fluid into the low pressure column at a feed point where comparable oxygen-nitrogen equilibrium exists; (b) withdrawing a fluid feedstream from the low pressure column where the argon content is relatively high for use as an input stream to the argon side-stream column; (c) identifying each stage of rectification within the low pressure column between the feedstream location and the feed point which exhibits a relatively high sensitivity to process changes in the air sepn. system; (d) selecting at least one of the identified stages of rectification which exhibits high sensitivity to process changes for monitoring the compsn. of the input feedstream to the argon sidearm column; (e) formulating a model defining the relationship between the nitrogen content in the feedstream and a compsn. variable in the low pressure column at the selected stage of rectification; (f) measuring the compsn. variable at the selected stage of rectification; (g) computing the concn. of nitrogen in the input feedstream to the argon sidearm column from the model in accordance with the value of the measured compsn. variable; and (h) controlling the operation of the process in response to the computation of nitrogen in the input feedstream.