Asymmetric integrally skinned capillary tubes were produced from the polymers PEI (polyetherimide) and PVP (polyvinylpyrrolidone) for vapour permeation modules which were applied for the separation of water from organic compounds and gases. Water treatment and recovery of desirable organic compounds was achieved. The capillary tubes had intrinsic permeability coefficients of 7.5 x I@' mol/m2+Pa for water and 1.6 x IC9 mol/rn'.s.Pa for 1 -propano1 for a 1 : 1 mass ratio vapour feed mixture under pyrolysis conditions. The vapour was fed at the interior of the capillary tubes with total pressure of 30 kPa; the permeate total pressure was 14 kPa, and the temperature was 86°C. Modules, with surface areas up to 1.0 m2, were constructed and tested with feed flow rates as high as 4 kg/h with a process development unit. Tests were performed with the vapours from wood chips and contaminated soils subjected to vacuum pyrolysis. he application of vapour permeation membranes to T industry is very recent. However, it is rapidly growing, aided by previous experience with reverse osmosis and pervaporation technology. The first industrial vapour permeation application was in 1989 (Sander and Janssen, 1991; Sander, 199 1) using flat sheet composite membranes originally designed for pervaporation for the dehydration of ethanol from 94% to 99.9%. Will and Lichtenthaler (1 992a,b) showed that polyvinyl alcohol/polyacrylonitrile composite membranes can be used for the separation of water/alcohol mixtures by pervaporation and vapour permeation. Deng et al. (1995) prepared flat sheet asymmetric polyetherimide (PEI) membranes and studied the recovery of solvents from air exhaust streams. Tanihara et al. (1992) prepared polyimide hollow fibers to study the separation of alcohol/water mixtures by vapour permeation.Regarding the effect of polyvinylpyrrolidone (PVP) additive to the casting solution, Cabasso et al. (1 976) made an intensive study. Miyano et al. (1990) showed that residual PVP remained in the membrane even after extraction of PVP in the gelation bath.