The invention provides a method for preparing
dichloroethane through direct chlorination by using
dry gas, which includes the following steps that
chlorine used as a
raw material is fed into a pipeline reactor through a
chlorine inlet
nozzle, simultaneously
dichloroethane mother liquor at the bottom of a bubble
tower enters the pipeline reactor from a
dichloroethane mother liquor inlet, the
dry gas is fed into the pipeline reactor through a
dry gas inlet
nozzle, and dichloroethane is produced through reactions. The dichloroethane enters the bubble
tower through a pipeline reactor outlet, steam on top of the bubble
tower enters a condenser,
tail gas is fed to following sections to be processed, condensed liquid of the dichloroethane enters a
storage tank, partial dichloroethane enters the bubble tower through a pump to be recycled, partial dichloroethane is used as products, and the dichloroethane
mother liquor at the bottom of the bubble tower is returned to the pipeline reactor to be recycled through a mother liquor pump. By means of the method, weight concentration of the obtained dichloroethane can reach more than 90%,
ethylene conversion rate in the dry gas is larger than 95%, reaction selectivity of
ethylene is larger than 98%, and the obtained dichloroethane can be used as a basic
raw material for preparing
polyvinyl chloride.