Pure argon recovery in an air separation plant

摘要

If the condensed head fraction from the pure argon column is returned at varying rates the operation of the column becomes unstable. In order to avoid this a storage facility is provided in the return line so that these variations can be compensated on commands from associated instruments. This storage facility is shown as (6, 7) and is the actual return line, now kept about 90% full of condensate under control of valve (8). This valve is actuated according to the volume present in the return line by controller (10) acting on a signal from instrument (9). The head fraction, together with the head fraction from the raw argon column (not shown), is condensed in heat exchanger (5). The column works at a pressure slightly above 1 bar so that gas can be vented to atmosphere. The permissible variation of pressure is to be less than 0.2 bar.