Molecular Sieve is porous solid, usually synthetic or natural Zeolite. Molecular Sieve is used as a desiccant, containing tiny pores of precise and uniform size that adsorb gases and liquids. It operates on molecular level and traps the adsorbed substance. Molecular Sieve offer adsorption selectivity based on molecular size, and the shape of the molecule. Molecular Sieve can absorb water up to 22% of its own weight. Molecular Sieve is often used in the Petroleum Industry, especially for purification of gas streams and in chemistry laboratory for separating compounds and drying reaction starting materials. Methods for regeneration of molecular sieve include pressure change (as in Oxygen concentrators), heating and purging with a carrier gas (as when used in Ethanol dehydration) or heating under high vacuum.