(179a) Periodic Cycled Separation Using Cops Trays

A realization of periodic cycled separation is presented which enables continuous vapor flow also during liquid drainage from the trays. With the proposed design, a new operation form is introduced where the trays are drained sequentially rather than simultaneously. Thus the vapor flow is not interrupted during the liquid drainage.

Previously we have compared separation factors and column efficiencies for a column stripping ammonia from water with air, using three different sets of internals: Conventional sieve trays, Sulzer BX gauze packings and periodically cycled trays. The periodic trays are advantageous compared to their predecessors. For different ratios of countercurrent vapor/liquid flow rates, column efficiencies are two times greater for periodically cycled columns than for columns with sieve trays. Depending upon the holdup and gas flow, the tray efficiency of a single periodic tray can be up to 300 % of an ideal stage.

In this communication we have explored operation at higher hold-up-to-gas-flow ratios, in order to obtain even higher column efficiencies. Also, the influence of carbon dioxide on pH measurement - central to the data logging procedure â?? are investigated. Also, aspects of design of period times are investigated.