SEPARATION OF FLUORINE COMPOUND FROM EXHAUST GAS IN SEMICONDUCTOR PRODUCTION USING MEMBRANE AND ADSORPTION CONTINUOUSLY

摘要

PROBLEM TO BE SOLVED: To efficiently separate and recover fluorine-containing chemicals from a gaseous stream containing a specific diluent gas and the fluorine- containing chemicals by contacting the gaseous stream with a membrane made from a specific material according to specified procedure. SOLUTION: The fluorine-containing chemicals B such as NF3, SF6 and CF4 are separated and recovered from the gaseous stream containing the diluent gas A such as nitrogen, helium and air and the chemicals B by contacting the gaseous stream with the membrane C made from polysulfone, polyetherimide, polypropylene, cellulose acetate, etc. In that case, the gaseous stream is pressurized to a prescribed pressure and heated and then contacted with the membrane. An impermeable materials rich in the chemicals B is further contacted with one or more additional membranes to produce a permeated stream rich in the diluent gas A and the impermeable material rich in the chemicals B. The impermeable material thus obtained is passed through an adsorption system to adsorb the stream further rich in the chemicals B.