Review on natural gas denitrification process

For speeding up the development of compact oil and gas reservoirs, shale gas and sub-quality natural gas(SQNG), the natural gas denitrification process has been received widespread attention all over the world in recent years. At present, four kinds of denitrification process are used in natural gas industry which including cryogenic, solvent absorption (Mahra process), pressure swing adsorption(PSA) and membrane separation. The flow-sheet of cryogenic process is complicated and the investment and cost are high. So it is only suitable for large unit treating high pressure feed gas with high concentration of N₂. The Mahra process is rarely adopted in industry recently as the selection of solvent because Mahra process is difficult and the solvent circulation rate is high, additionally, it needs refrigerating system. The titanium silicate molecular sieve of which the aperture size can be adjusted and controlled was applied to the Molecular Gate denitrification process. The key technology made it become the main technique of medium and small denitrification units. Along with the successful development of special membrane separation material, the membrane separation denitrification process advances very fast, but the properties of the membrane materials need to be further improved.