This program was divided into two phases. The objective of Phase I was to demonstrate on a laboratory scale the economical separation of nitrogen from nitrogen-methane gas mixtures using a novel inorganic membrane to obtain pipeline quality natural gas with less than 4 percent nitrogen. The objectives of Phase II included bench-scale demonstration of nitrogen rejection from an actual, high nitrogen content natural gas source to produce pipeline quality gas and an economic comparison of this inorganic membrane separation technology with commercial nitrogen removal processes. The proposed method utilizes thin ceramic membranes on the surfaces of channels passing through a ceramic monolith support to selectively remove nitrogen from nitrogen-hydrocarbon gas mixtures. The membrane layer is composed of fine ceramic nanosize particles having an average diameter of 4 to 6 nanometers, produced by an IGT-patented process. A new proprietary fabrication method developed by IGT overcomes the limitations of solvent and sol-gel type inorganic membrane production methods. In this novel solvent-free process, membranes are formed by isostatic pressing. No expensive precursors are needed, and the membrane defects caused by solvent drying are avoided. Nitrogen is selectively removed from natural gas with this membrane at ambient temperature with low hydrocarbon gas loss and inlet gas pretreatment requirement. Separation efficiency is high because a high differential pressure provides the driving force to draw nitrogen through the membrane by size exclusion (molecular sieving) and surface diffusion mechanisms. Since the methane andother hydrocarbons do not pass through to the low pressure side of the membrane, no natural gas recompression is necessary.