Periodic cycling of distillation columns using a new tray design

Computer simulations of periodically cycled columns predicted improvements in column performance of greater than 200% for systems with nonlinear equilibrium curves. Experiments distilling methanol‐water mixtures have verified those predictions for periodic cycling with a single plate. The extension of the theory to multiple‐plate columns fails in usual distillation apparatus due to liquid mixing during the liquid flow period. To overcome this problem a new tray design consisting of a sieve plate and inclined surfaces has introduced an effective liquid time delay. Although the predicted efficiencies of 200% were not realized due to vapor movement hindering the tray action, a wide range of operating conditions provided good overall column efficiencies of 140%.