Abstract: When tap water was used as the source of circulating cooling water,the increasing bicarbonate concentration resulted from water evaporation,and chlorine ions in tap water led to corrosion and chemical deposit in the dry ice expanded tobacco system and many negative consequences,such as,higher discharge pressure and temperature of CO₂ high-ow pressure compressors,CO₂ exhaust to atmosphere because the pressure in storage tank was higher than the setting value,serious rust on condenser pipeline,sludge resided in system pipeline and heat exchanger,and the normal running of the system was affected accordingly.Therefore,the chemically treated tap water of low chlorine level was used,washing and precoating were carried out at the beginning of running,and anticorrosive,bactericide and algicide were applied regularly.The improved system ran well,deposit and corrosion were contained within a normal range through dynamically water quality monitoring,timely agent dosage adjusting and regular cleaning.