Design And Development Of Integrated System For Spraying Exhaust Gas Treatment Technology In Furniture Industry

Surface coatings are widely used in the furniture manufacturing industry.Spraying exhaust gas is generated during the coating process,including paint mist and volatile organic pollutants(VOCs).At present,there is no good technologies and methods for the treatment of paint mist in the industry.At the same time,the equipment for mainstream VOCs processing technology has a high investment,complicated operation and maintenance,and puts great environmental pressure on small and medium-sized enterprises in the paint spraying industry.Aiming at this environmental protection situation,this paper designs a reasonable and economical technology integration system.Based on laboratory research,through integrated device design,manufacturing,and field tests,the treatment effect of the system process in actual furniture spraying exhaust gas is investigated to provide technical support for the treatment of spraying exhaust gas in the furniture industry.First,this paper carried out wet integrated process design and paint mist purification test.Analysis of paint mist characteristics shows that under simulated spraying conditions,the optimal pressures for water-based paint and oil-based paint are 0.3 MPa and 0.4 MPa,respectively.At the same time,the particle size distribution of paint mist produced by oily paint under the optimal pressure ranges from 5.4?43.4?m,which is almost normal distribution.Among them,paint mist smaller than 10?m accounts for about 50%of the total paint mist.Subsequently,this article combined the paint mist characteristics to carry out the design,manufacture and test of wet paint mist purification device,to investigate the treatment effect of paint mist on the device,and to verify the rationality of the design.During the test period,the concentration of paint mist of the exhaust gas sprayed by the furniture factory was 85?200 mg/m~3.After the treatment of the device,the paint mist concentration was reduced to 1.5?3.1mg/m3,and the removal rate reached 98%.in which the improved sieve-tray tower contributed 94%particles removal.Secondly,a vacuum ultraviolet(VUV)oxidation degradation experiment was carried out for VOCs in spray paint.Pilot site exhaust gas sampling analysis showed that the main pollutants in the exhaust gas were ethyl acetate,toluene,butyl acetate,ethylbenzene,and xylene(m-,p-xylene,ortho-xylene).Comprehensive consideration to determine laboratory pollutants toluene and butyl acetate.Subsequently,an experimental device was designed,and a structure in which VUV lamps were arranged in parallel with the exhaust gas flow was used to carry out experiments on influencing factors and by-products of ultraviolet vacuum oxidation(VUV).Experiments showed that the separate VUV oxidation technology was suitable for processing ultra-low concentration(?25 ppm)VOCs exhaust gas at a reasonable configuration power.At the same time,some of the degradation by-products(such as formic acid,acetic acid,etc.)have better water solubility and can be treated by spray absorption.Finally,this paper explores the purification effect of VUV oxidation and ozone catalytic coupling technology on pollutants.Experiments showed that under the conditions of relative humidity of 75%and residence time of 3 s,the coupling technology has a better treatment effect on low-concentration(25 ppm)pollutants,and the removal rates of toluene and butyl acetate reach 86.3%and 90.1%,respectively.Finally,based on the above research,the paper designs,manufactures and tests integrated system devices,and examines its purification effect on paint mist and VOCs in spraying exhaust gas from furniture factories.At the same time,the analysis and discussion of secondary pollution generation,treatment and system equipment operation cost were carried out.Field test results showed that the concentration of imported paint mist was 97?198 mg/m~3,and the concentration of imported VOCs was55?82 mg/m~3.At the end of treatment,the concentration of paint mist was reduced to1.5?2.0 mg/m~3,and the removal rate was 98.6%.The average removal rates of OVOCs and BTEX were 80.6%and 38.4%,respectively.The removal rates of total volatile organic compounds(TVOCs)were 47?54%.In terms of secondary pollution,the amount of paint slag for treating 1000 m3 of exhaust gas was about 0.933 kg,which need to be disposed of by a professional hazardous waste treatment company.The replacement time of the circulating wastewater was 15 days,and the coagulation air flotation-delayed biological treatment process can be adopted.In terms of operating costs,the comprehensive operating cost of the 1000 m~3/h pilot plant was10.44 yuan/h.