In this work, we prepared asymmetric composite membranes based on carboxymethyl cellulose (CMC) with degree of substitution (DS) of 1.06 in order to develop a new dehydration membrane having high selectivity and permeability. New composity membranes were produced by casting CMC polymer solution on high density nonwoven fabrics. We have investigated practical pervaporation performances of aqueous alcohol solutions; especially iso-propyl alcohol(IPA) which is usually used during the semi-conductor rinsing process. For the application of the membranes on a technical scale, we have made a plate and frame type pervaporation module unit. The separation factor and the flux for the composite membrane DS were 85~811 and 0.07~0.52 kg/$m^2$.h in 90~98 wt% aqueous IPA solutions at 6$0^{circ}C$, respectively. The IPA concentration on the membrane performance using pervaporation module system could be increased from 95.04 wt% to more than 98.50 wt% in about 9h at operation temperature of 7$0^{circ}C$ using the pervaporation module system.