The Research On Corrosion Mechanism That Making Fly Ash Into Crystal AlCl3 System

Fly ash is after coal burning solid waste emissions from heat-engine plants.With the development of Chinese economic in recent year,the storage volume of fly ash is increased by the increasing application amount of coal.Fly ash as a kind of solid pollution which serious damage to the ecological environment.As the found a high aluminum fly ash in our country,So many attitudes paid on how to make full use of fly ash.The present study is just to verify the feasibility of extraction of alumina on the chemical process of fly ash,and no corrosion study in the process of chemical production equipment research,so the study on corrosion mechanism that making fly ash into crystal AICl3 system is of great significance.In this paper,the equipments working conditions and equipment conditions are considered.The corrosion failure of that making fly ash into crystal AICl3 system's heat exchanger is analyzed,through the study on failure forms of heat exchanger made by TA10 alloy,obtained the corrosion type of the heat exchanger is dew point corrosion and corrosion of welds,the corrosion of equipment is accelerated by hydrogen brittleness and erosion corrosion under the condition of dew point corrosion.Temperature and concentration of HCl gas are the main factors that make the heat exchanger shell side failure,Temperature concentration of AlC13 and pH are the main factors of tube side.TA10 alloy,used to make the equipment making fly ash into crystal AlC13,is tested electrochemically by Princeton 2773 electrochemical workstation.With the help of orthogonal test,TA10 alloy is tested under the working condition of tube side by using the electrochemical noise test,the electrochemical impedance spectroscopy test and polarization curve test.By range analysis confirm temperature and pH value are main factors influencing the metal corrosion.In the temperature range of 70??90?,The noise resistance and the charge transfer resistance are the biggest when the temperature is 90?.The pitting potential is the biggest when the temperature is 80?;pH range of 1?3,The noise resistance and the charge transfer resistance are the biggest when the pH is 2.According to the research conclusion has been making a test analysis,for the choice of materials and chemical process improvement suggestions were put forward.