| It has been wide-accepted that the dominance of the coal-fired power generation in china’s power generation industry will not change within a short time,because of the primary energy structure of rich coal and poor gas as well as petroleum,and that mercury pollution comes from the gas emissions from coal-fired power plants.As for the subject of the Experts at home and abroad have shown that activated carbon modified by halogen compounds and fly ash have a good effect on the removal of mercury from flue gas,while the addition of halogen compounds will lead to the corrosion of metals in power plants.There are less studies on the corrosion of bromine,compared with that on the chlorine because of its small amount in coal.So,Q235 carbon steel and 304 stainless steel were selected as the experimental material with sodium bromide,potassium bromide,calcium bromide,hydrogen bromide and hydrogen chloride as the halogen compound modifier to analyse the corrosion characteristics of these two kinds of metal under the same concentration,by weight loss method,electrochemical test method and scanning electron microscope observation method.Practically,HBr modifier,which has been taken into practice,was also applied to analyzing the corrosion characteristics of the fly ash modified with and without HBr modifier under80℃,130℃ and 180℃,by salt coating method.Experimental results show that Q235 steel losts the most of its weight in HCl solution and has the highest corrosion velocity,followed by HBr solution;among the four bromide solution,the least corrosion weight loss and the lowest corrosion velocity both come to Q235 steel,and as the soak time increases,the corrosion velocity of carbon steel sample firstly increases and then decreases.As for the salt coating experiment,hydrobromic acid will come up and dew point corrosion will appear on the metal surface when the temperature is close to HBr dew point;and when it is above the HBr dew point,g aseous bromine directly eroded metal sample,and a ctive oxidation will appear.304 steel will be locally errosed the velocity of that comes the highest in the HCl solution.Moerover,HBr will be pitting corrosed and the more the temperature increases,the serious the pitting corrosion will be,the concentration of bromine in the hole will increase,and the b romide concentration inside the hole is higer than that of the outside ones. |
