Study On The Improvement Of Exhaust Gas Treatment Of Polyformaldehyde

Waste gas-formaldehyde is a kind of harmful pollutant discharged from chemical production.Its odor could be easily identified even decreased to PPM level.It will cause environment pollution and be harmful to human if waste gas-formaldehyde was discharged into the atmosphere directly without any treatment,which are of restricting the survival and development.In this theme,the nitrogen circulation is used to granulate and dry the materials from the spray granulation unit of paraformaldehyde production via the analysis of our company.The formaldehyde content of circulating process gas is higher than 80mg/Nm3.Comparaly,the old treatment system can only reduce the content to 40-50mg/Nm3 through the absorption tower by physical absorption of water,which is far from the new national standard:less than 10 mg/Nm3,the main study is listed as follow:1.The process route of formaldehyde disposal by combustion method was confirmed at home and abroad.In order to maintain lower working temperature,platinum was used as catalyst and alumina as carrier the catalysts for gas treatment were investigated.Furthermore,palladium catalyst was added in the upper layer to reduce energy consumption in order to reduce the initial triggering temperature of the reaction.2.After determining the catalyst and the initial process,the preliminary design and calculation of the process package were carried out,including the confirmation of the process flow,the formulation of the process parameters,the hazard analysis of HAZOP process,the steam heating system in the operation unit,the electric heating system,the reaction system,the recovery and utilization of heat,etc.Installation,pressure test and purge were carried out after the equipment and catalyst were in place.3.Air debugging was carried out for the tail gas treatment unit&connect with paraformaldehydespray granulation exhaust emission system after confirming that all the system can run normally.Start production as standard,the results show that the concentration of formaldehyde is less than 5 mg/Nm~3,which meets and exceeds the design requirements.Through the calculation for investment and operation cost,the cost of paraformaldehyde products decrease about CNY4.5/MT.Finally,the problem for over-standard discharging of waste gas has been resolved and ensures the normal production.