Abstract: A process for the pyrolysis of 1,2-dichloroethane (EDC) in a pyrolysis furnace (1) involves feeding liquid EDC into a convection heat transfer tube (2) for preheating, channeling an intermediate flow of preheated EDC into a radiation heat transfer tube (3) for further heating, thereby pyrolyzing a part of EDC into vinyl chloride monomer, and discharging a decomposition gas flow from the pyrolysis furnace. Potential heat is recovered from the decomposition gas by using a double tube type heat exchanger (10) consisting of outer and inner tubes, that is, by channeling the intermediate flow through the outer tube (11), channeling the decomposition gas through the inner tube (15) for heat exchange between the intermediate flow and the decomposition gas, and feeding the heat acquired intermediate flow into the radiation heat transfer tube (3).

Abstract: A process for the pyrolysis of 1,2-dichloroethane (EDC) in a pyrolysis furnace (1) involves feeding liquid EDC into a convection heat transfer tube (2) for preheating, channeling an intermediate flow of preheated EDC into a radiation heat transfer tube (3) for further heating, thereby pyrolyzing a part of EDC into vinyl chloride monomer, and discharging a decomposition gas flow from the pyrolysis furnace. Potential heat is recovered from the decomposition gas by using a double tube type heat exchanger (10) consisting of outer and inner tubes, that is, by channeling the intermediate flow through the outer tube (11), channeling the decomposition gas through the inner tube (15) for heat exchange between the intermediate flow and the decomposition gas, and feeding the heat acquired intermediate flow into the radiation heat transfer tube (3).

Abstract: Semipermeable membranes useful in reverse osmosis and a process of preparing them comprising deacetylating naturally occurring chitin to produce chitosan, making a film of chitosan salt from an acid diluted aqueous solution of the chitosan, converting the film of chitosan salt to a film of chitosan having free amino groups by neutralizing the acid groups, and then subjecting the film of chitosan to a chemical treatment with an organic acid, by which to convert the chitosan to the acetylated form, having a degree of acetylation from about 0.3 to 0.8, to produce the reverse osmotic membranes.The products have excellent chemical properties as well as mechanical strengths sufficient to withstand the pressure difference in the operating condition.