Study On Emission Characteristics Of VOCs Exhausted From Fiber Hot-pressing Of Continuous Press

VOCs, which is one of the key precursors of atmospheric secondary organic aerosolpollution, plays an important role in the formation of fine particle aerosol and PM2.5, also leads tothe haze phenomenon. Wood-based panels will release large amounts of volatile organiccompounds in the process, which is harmful to human and the environment. This thesisinvestigated the VOCs emission of poplar as the main raw material from an annual output of100,000m~3MDF hot-pressing, composition, concentration, total emissions and per unit ofproduct emissions of VOCs were analyzed by HPLC and GC/MS.In order to grasp the poplarMDF VOCs of continuous presses exhaust, total VOCs emissions control of fiberboardmanufacturing, evaluation of green products and provided purification of the hot exhaust VOCs.The main conclusions obtained from the research are as follows:Firstly, analysis of poplar as raw materials commonly used in East China, the annualproduction capacity of100,000m~3of MDF continuous flat pressure pressing machine exhaustVOCs. The results showed that the exhaust TVOC mainly composed of toluene(31.13%),n-hexane(12.51%), andα-pinene(11.21%), the exhaust aldehyde and ketone mainly composed offormaldehyde(40.78%), acetaldehyde(22.22%), butyraldehyde(10.62%) and acetone(12.12%).The concentration of TVOC was0.7793mg/m~3, aldehydes and ketones was2.8145mg/m~3.Secondly, by the actual total exhaust volume and concentration of TVOC, aldehydes andketones, estimated annual output of100,000m~3of MDF continuous press exhaust, the annualemissions of TVOC was272kg, unit product of VOCs releasing quantity was3.09g/m~3, theannual emissions of aldehydes and ketones was982kg, unit product of aldehydes and ketonesreleasing quantity was10.54g/m~3. From the total amount control and artificial clean productionlevel’s point of view, hot-pressing in the production of MDF as an important section, the releaseof VOCs should not be ignored, to reduce its production and emission worthy of attention andstudy.Thirdly, under the same conditions as in the raw materials, the pressing parameters,adhesives, etc, analyzing and comparing of the VOCs component in the multi-opening press andcontinuous press, it showed that multi-opening press hot-pressing exhaust contains morealdehydes and ketones, and terpenes, and continuous press hot-pressing exhaust contains moreBTEX and alkanes.Because the continuous press used the lubricant. The unit product of theTVOC and aldehydes and ketones emissions of the continuous press is lower than the emissionsof multi-opening press.Fourthly, analysis the effect of wet processing method purification VOCs, the data indicatedthat the concentration of treated exhaust VOCs were2.0215mg/m~3, annually reduce the547.5kg VOCs emissions, the annual emissions of VOCs still was706.9kg. At the same time it brongthe sewage problem.Fifthly, an overview of the nature of the main component of the continuous presshot-pressing exhaust VOCs, by comparing the direct oxidation and catalytic oxidation process,analyzed the feasibility of catalytic oxidation to purify the hot-pressing exhaust VOCs, provideda theoretical basis for the latter part of the purification.