(A) study on freon-12 hydrate formation for desalination

Abstract

The yield and formation rate of freon-12 hydrate in the system of freon 12-sodium chloride-water were investigated by the semi-batch and continuous experiments. The effects of stirring speed, temperature difference from equilibrium point and freon-12 flow rate ( or amount of freon) on the yield and formation rate of freon-12 hydrate were obtained. The yield and formation rate of freon-12 hydrate increased as the stirring speed increased. This stirring effect was more serious as increasing the amount of liquid freon in a crystallizer. In the semi-batch experiment, unevaportated freon or freon loss considered to the flow rate of liquid freon at the same yield. In the continuous experiment. the formation rate of freon 12-hydrate in sodium chloride solution (about 3.5wt\%) was directly proportional to the ratio of inlet flow rate of NaCl solution to that of liquid freon(W/F). But the formation rate of freon 12-hydrate was slower than those of propane and freon 31 hydrates. The cold energy of liquefied natural gas(LNG) can be used to liquefy the freon-12 gas produced from the hydrate process. The regasified LNG by giving up its cold energy can be fractionted to a highly pure methane and heavy hydrocarbons through the simple process which consists of a flash drum and a six stage distillation column. And the effectiveness of the process is confirmed by a computer calculation.