Analysis of the quick corrosion of blast furnaces’gas pipes after the installation of dry-type de-dusting equipment and discussion about measures

Compared with the traditional wet-type de-dusting technology,the dry-type de-dusting technology is considered to be environmentally friendly and energy-saving.However,the pipes carrying the de-dusted blast furnace gas (BFG) tends to be corrosive more quickly and seriously.In order to investigate the reasons for the quick corrosion,the gas pipes and auxiliary bellows installed in Baosteel’s newly built BFG dry-type de-dusting system are studied.The corrosive properties of the condensed water,such as the pH value,are measured and analyzed.Meanwhile,various factors that may influence the corrosion rate of the pipes are studied by experiment.On the basis of the investigation and research,the causes of corrosion and leakage on the pipes are discovered.It is the process of dry de-dusting that is responsible,to a large extent,for the quick corrosion of the pipes.The equipment of spray tower is introduced and its effects are then discussed.This tower is designed to eliminate most of chloridion and neutralized the acid by spraying the alkaline water to the de-dusted gas flow.The practical operation shows that the tower helps to lessen the corrosiveness of the dry de-dusted gas effectively.The last part of this study analyzes the possible impacts of the dry-type de-dusting process of the newly built blast furnace (BF) on the main BFG piping which has been in the state of being corroded for years by estimating its potential corrosion rate,and some suggestions on maintenance are given as well.