Study On Corrosion Characteristics Of Alcohol-based Fuel During Combustion And Utilization

Alcohol-based fuel has been rapidly developed under the background of increasing diversified energy demand.Composed of methanol and diesel fuel in a certain proportion,alcohol-based fuel is divided into MF100,MF75,MF50 according to the volume fraction of methanol.The fuel is simple to prepare and environmentally friendly,to some extent,can alleviate fossil fuel crisis.It has been generalized and applied to small equipments such as industrial boilers and kiln.The corrosion of alcohol-based fuel during combustion and utilization mainly exists in storage process,low-temperature corrosion of combustion and flue gas condensed acid.The conventional corrosion of three kinds of alcohol-based fuel during storage was studied.The results show that the indexes of alcohol-based fuel are all ideal,and copper corrosion is at level lb.The metals show passivation behavior with the increase of diesel oil proportion in alcohol-based fuel.The corrosion resistance of stainless steel is stronger in MF100 fuel and MF75 fuel than in carbon steel.Brass has poor corrosion resistance in MF50 fuel.The corrosion rate of metals decreases as the proportion of diesel in fuel increases.Under normal standard storage conditions,the macro parameters of chloroprene rubber(CR),nitrile rubber(NBR)and silicone rubber(MVQ)increase with the diesel fuel content in alcohol-based fuel,which are suitable for alcohol-based fuel with high proportion of methanol.As for fluorine rubber(FKM),its macro parameters increase as the proportion of diesel in alcohol-based fuel decreases,which is suitable for alcohol-based fuel with low proportion of methanol.The research about acid gas and acid dew point of the flue gas indicates that under standard operating conditions with an oxygen content of 3.5%,the moisture in the flue gas decreases as the proportion of diesel in the fuel increases,but the SO3 content in the flue gas increase with the diesel proportion in the fuel.And there is almost no acid gas in flue gas of MF100 fuel.The acid dew point of flue gas increases with the diesel content in fuel.As for MF 100,the acid dew point is close to the temperature of moisture condensation.At 200℃ flue gas temperature operating conditions,the total number of acid ions in the flue gas condensate of diesel fuel is large,and the sulfate ions increase with the diesel content in the fuel.But the acid condensation of other flue gas has weak acidity.The corrosion phenomenon and corrosion rate of the metals in acid condensation of flue gas were compared and analyzed by electrochemistry and static immersion.Stainless steel had better corrosion resistance to four kinds of acid condenstion,of which Q245 steel had inferior corrosion resistance and brass had the same corrosion resistance as corten steel.The acid condensation of diesel fuel combustion flue gas has strong corrosiveness to metal,and the corrosion rate decreases as the proportion of methanol in the alcohol-based fuel increase.