When oil is transported in a cold region in winter,the pipelines that pass through the frozen earth will become so cold because of the water in the oil that there will be some ice blocks in the pipelines.

For the light hydrocarbon recovery unit at Qiulin, ice jam has occurred many times since August 22, 2002 and has bought many troubles to normal production.

Ice jam of pipes for transporting oil and gas in winter threatens momently the safety running of petrochemical units in cold area.

Method According to physical and chemical features of CO2, through studying phase pattern of CO2 gas well during testing, primary throttling process was adopted to maintain pressure at the level before throttling, to maintain proper temperature, and to keep the equipment and lines from dry ice blockage.

The problem of freezing damage for Hailer type air-cooling system is presented, the mechanism for the random freezing damage of air-cooling column elements in the system are analyzed, and the technical measures to solve the problem caused by ice-burl block are contributed.