Experimental Research On Degradation Of Indoor Formaldehyde By Plasma Combined With Catalyst

The issue of indoor air pollution is mainly caused by formaldehyde andbenzene series compounds. The research on indoor formaldehyde degradationis of great importance for IAQ management and human health. Recentlyindoor air pollution control has already achieved great progress, anddeveloped several ways to control indoor air pollutant were developed,including absorption, negative ions, plasma, photocatalytic degradation and soon. Although plasma could be used as sterilizer, deodorization and dustprecipitation, highly efficient VOCs removal rate still cannot be realized andexcessive ozone was generated in the process which could be harmful tohuman. Photocatalytic degradation method was developed in past twodecades with great potential value, but the required UV light put a lot ofinconvenience and restrictions to actual applications. This thesis adopted thecombination method of formaldehyde degradation by non-thermal plasmacombined with catalyst, which utilizes the plasma generator to replace UVlight as energy source, and generates the coupling effect to efficiently removal formaldehyde.This thesis adopted the method of formaldehyde degradation bynon-thermal plasma combined with catalyst. The plasma generator wasdesigned by our research team, and the catalyst used in this experiment wassynthesized by loading H-ZSM-5/TiO2(P25) catalysts on the active carbonsupport. The thesis simulated the degradation of formaldehyde in a sealed testcabin and a tunnel ventilation system. The following conclusions can bedrawn:(1) Through formaldehyde degradation experiments in a sealed test cabinby three methods, the efficiency and rate of formaldehyde degradation byplasma combined with catalyst is the highest among them. The higher level ofdegradation and velocity mainly comes from massive active ions in plasmaflow and the coupling effect of plasma combined with catalyst. The synthesisof catalyst and techniques are important influence factors concerning thedegradation efficiency. The catalyst plate loading H-ZSM-5/TiO2(P25)catalyst on the active carbon support realized ideal degradation offormaldehyde.(2) Through comparison experiments with different experimentalconditions in the sealed test cabin, the study focused on influence factorsincluding distance between catalyst-plate and central electrode, anode or cathode of central electrode. The formaldehyde degradation efficiencyreached83%and formaldehyde concentration decreased to0.07ppm within1.5hours after the adsorption balance, under the experiment condition ofcentral anode electrode, the distance between catalyst-plate and centralelectrode15mm and flow velocity4.5m/s.(3) Through degradation of formaldehyde experiments in tunnel systemto simulate the open ventilation system, byproducts research verified that NOxconcentration has not been obviously increased. And the ozone generated inthe degradation process, has been controlled by adding a ozone removal plate.(4) The integration structure design of plasma and active carbon catalystplate, as well as optimized experimental results, may be utilized in design anddevelopment of indoor air purifier.