GAS SEPARATION USING MEMBRANES .2. DEVELOPING A NEW MEMBRANE FOR THE SEPARATION OF HYDROGEN AND CARBON-MONOXIDE USING THE TARGETING APPROACH

This paper describes the concept of ''targeting'' the development of n ew membranes such that the resulting membrane separator will be econom ically viable in a particular commercial process. The separation of ca rbon monoxide and hydrogen for the production of acetic acid is used t o illustrate the development of a new membrane material using the targ eting procedure. It is shown by economic evaluation of the complete pr ocess that the cost of separation can be related to the permeability a nd selectivity of the membrane. Costs upstream and downstream of the s eparator are taken into account. The same cost may be achieved by many different combinations of membrane permeability and selectivity; ther efore, iso-cost lines can be drawn on a plot of permeability and selec tivity which provides a guide for the development of new membranes. A new membrane material has been selected for the separation of carbon m onoxide and hydrogen for the acetic acid process. The copolymer was sy nthesized and dense homogeneous membranes were manufactured for the me asurement of gas transport and physical properties. The membrane has s ubstantially different gas transport properties from currently used co mmercial membranes. If this membrane was developed, it would be expect ed to result in a reduction in the cost of carbon monoxide separation to 40% of the cost of the currently used method, cryogenic distillatio n.