Research On The Release Characteristics And Purification Technology Of Wood UV Painting Exhaust VOCs

The volatile organic waste gas released in the process of industrial production is a kind of toxic and harmful gas,which will not only cause environmental pollution but also seriously harm to the health of residents when discharged into the atmosphere.With the progress of the society,the improvement of residents’environmental awareness,organic waste gas pollution problem has already become the focus of attention,according to current situation of pollution of the environment,national and local government departments have promulgated a series of regulations and environmental standards,but to a specific industry standard of exhaust pollution was not yet perfect,so how to solve the organic waste gas pollution in industrial process,and can efficiently to deal with waste recycling,to save energy and protect the environment,realized the goal of green sustainable production,has become the real challenges facing the industry in the process of upgrading.In the process of wood floor processing,paint finishing was an indispensable part.This study takes representative paint finishing exhaust in a certain floor production process as the research object,and measures the coating by thermal desorption-gas chromatography.The main components of VOCs released in the exhaust gas and their mass concentration;According to the type of pollutants exceeding the standard in the exhaust gas,phosphoric acid modified activated carbon was used as the adsorbent,and the adsorption device developed by ourselves has studied the influence of the thickness of the adsorbed layer on the adsorption efficiency.The saturation time of activated carbon was determined and the corresponding adsorption saturation curve was obtained.The variation law of characteristic pollutant removal rate was obtained.The regeneration test of adsorption saturated activated carbon was carried out by low temperature microwave desorption.The experimental determination of activated carbon was carried out.Desorption conditions,according to the adsorption results,the adsorption capacity,regeneration rate,replacement time and other parameters of activated carbon were calculated.Desorption and regeneration of activated carbon was again subjected to adsorption test to ensure the number of cycles of adsorption-desorption regeneration-resorption test.According to the results of the adsorption-desorption cycle of this study,an adsorption-desorption implementation scheme was designed for the response emission of wood floor UV finishing exhaust,and preliminary economic analysis was carried out.The main conclusions could be described as follows:(1)The composition and total mass concentration of VOCs in the UV coating exhaust of won floors were measured and analyzed,and the types of VOCs and their mass concentrations exceeding the current national ambient air quality standards were identified.The study found that the total concentration of VOCs in the UV finishing of wood flooring was 2.565～3.146 mg/m~3.The main pollutants were benzene series(48.16%),alkanes(5.82%)and esters(34.33%).Main features Contaminants were benzene(1.266 mg/m~3),toluene(0.017 mg/m~3)xylene(0.078 mg/m~3),styrene(0.077 mg/m~3),ethyl acetate(0.963 mg/m~3),of which benzene concentration Exceeding the limits of relevant national and local standards.(2)The one-stage,two-stage and three-stage adsorption and purification of exhaust pollutants were carried out,and the effects of different adsorption layers on the purification effect of VOCs were studied.The results showed that the one-stage,two-stage and three-stage adsorptions reach adsorption saturation at 70 min,90 min and 120 min respectively,and the removal rate increases with the increase of the thickness of the adsorption layer.The multi-stage removal effect was more remarkable than the one-stage removal effect.(3)Through the multi-stage adsorption-desorption after three cycles,the two-stage and three-stage adsorption amount attenuation changes were studied.The results showed that the two-stage adsorption amount was higher than the three-stage adsorption amount,and the two-stage adsorption was more sufficient.Activated carbon was partially not fully saturated during the staged filling purification.(4)Microwave desorption of adsorbed saturated activated carbon was carried out at 170°C using a microwave reactor.The results showed that the desorption rate of saturated activated carbon reached 97.48%after desorption for 20 min.Desorption temperature rised sharply and then gradually stabilizes.(5)The optimum parameters of the UV coating process for wood floor cleaning were determined by adsorption-desorption regeneration-resorption test:the amount of activated carbon was 2000 kg,the filtration wind speed was 1.97 m/s,the regeneration cycle was 59 days,and the replacement cycle was 240 days.