Study On Corrosion Characteristic Of Further Biochemical Treated Coal Chemical Wastewater Reusing

Coal chemical industries result in a large amount of wastewater.It is one ofkey measures using coal chemical reclaimed water as circulating cooling water toalleviate the industrial water crisis in china.The primary challenges ofwastewater reuse for cooling arise from low quality.In circulating coolingsystem,the water constituents can cause severe metal corrosionproblems.Researching the corrosion characteristics and the changing rules of thewater concentration when coal chemical wastewater reused as circulating coolingwater would help us solve practical problems.The effect of inorganic ions and organic matters on the mineral corrosionwas studied in this paper and the control factors for carbon steel corrosion wereresearched;microbiological induce corrosion of carbon steel,316stainless steeland H61copper were researched comprehensively by electrochemicalmethod;Using further treated coal chemical wastewater, a dynamic test was setup to simulate the circulating cooling water system.It is indicated that NH4+-N, SO42-and Cl-showed strong effect on mineralcorrosion on carbon steel specimen.TDS and SS increased the corrosion ratewhen their concentration rise. The effect of flow velocity was larger thandissolve oxygen.The mains organic pollutants of coal chemical wastewater actedas an organic inhibitor.The scanning electron microscopy (SEM) analysis resultsindicated that corrosion of carbon steel occurred on all the surface and exhibitedpitting corrosion characteristics.Through energy dispersive pectrum (EDS)analysis,main component of corrosion products were Fe and O,also include littleS.MIC on stainless steel was the biggest though corrosion of carbon steel andcooper was more serious than stainless steel in further treated coal chemicalwastewater.so microorganisms in stainless steel system should be pain moreattention in practical industry. The present of microorganisms didn’t change thetime rules of corrosion potential, current density and corrosion rate, but thepresent of microorganisms aggravated corrosion of both stainless steel andcarbon steel,while alleviate the corrosion of cooper at the beginning ofmicroorganisms present.Dynamic simulation experiment indicated that maximum concentration ratioof the reclaimed water in this study was3.328. Concentration of NH4+wasdeclined in the precess of circulating and HCO3-concentration increasedslowly.The concentration ratio of Ca2+,COD and SO42-were all smaller than the system concentration ratio.Also microorganisms was present in circulatingsystem.