An In-Situ Thermally Regenerated Purification Slice And Purifying Method For Indoor Gaseous Pollutants Removal

In the past two decades,China is facing rapid urbanization and the urban residential building area has been increasing.The application of indoor decoration materials has caused serious indoor volatile organic compounds(VOCs)pollution,which greatly threatens human health.Therefore,effective purifying methods for indoor VOCs are urgently needed in China.Thermal regeneration is a promising purifying method nowadays.By regenerating the material regularly,the performance of the material can be recovered and is suitable for the purification of indoor pollutants with low concentration.However,thermal regeneration method has following disadvantages:the pollutants are difficult to desorb,causing the regeneration time is long and the energy consumption is large.To overcome these shortcomings,following researches have been carried out:(1)The concept of energy consumption per unit of effective dimensionless clean air volume(W~*)was put forward considering both the purifying performance and energy consumption of regeneration.Based on the parameter,a suitable material for adsorption-regeneration cycle was selected.In addition,hybrid storage/catalysis(HSC)material based on transition metals for formaldehyde was studied and evaluated.(2)A thermal regeneration module is proposed:an in-situ thermally regenerated purification slice for indoor gaseous pollutants removal.By mechanical design and mass transfer process optimization,the purification slice overcomes the problem of high mass transfer resistance inside the purifying material.This module achieves rapid and efficient purification and regeneration process with low pressure drop.(3)The adsorption material and HSC material as described in(1)were used to prepare purification slice with optimized preparation method.With face velocity of 0.8m/s,the one-pass efficiency of the slice using adsorption material for formaldehyde and xylene reached 49.9%and 71.9%,respectively.The one-pass efficiency of HSC purification slice for formaldehyde was 87%.The thermal regeneration ratios of both two kinds of purification slices exceed 98%.(4)A mathematical model describing the mass transfer process of the purification slice was proposed.Given operation parameters,this model can predict the performance of the purification module,thus providing an effective tool for optimizing the design of the purification module and the purification-regeneration process.In addition,based on the model of the purification slice and the fix bed model,the regeneration performance of two types of purification modules were compared.The dimensionless effective clean air volume W~*for formaldehyde were 8.07 k J/m~3 for purification slice and 129.68 k J/m~3for fix bed,respectively.The W~*for xylene was 9.37 k J/m~3 for purification slice and and70.87 k J/m~3 for fixed bed,respectively.Compared with granular fix bed,W~*of the purification slice decreased by 94%for formaldehyde and 87%for xylene.The above work provides method and design tool for long-term and efficient purification of indoor gaseous pollutants.