| With the gradual improvement of life quality,indoor air quality has been paid more and more attention by people,government and media.VOCs released from building decoration materials and indoor furniture seriously pollute indoor air,endanger human health,and even have the risk of cancer,among which formaldehyde is one of the pollutants with the widest source and the most serious pollution.Effective control of indoor formaldehyde concentration,improvement of indoor air quality and provision of a healthy and comfortable living and office environment for people are indispensable parts of a better life.PCO technology has the characteristics of energy-saving,environmental protection,wide application range,high mineralization efficiency,simple operation conditions,low oxidation temperature and no secondary pollution.It is an effective means to remove indoor air pollutants.The application of the PCO technology to the varying environment,and the designation of the small,practical and low-cost photocatalytic air purifier is of great significance.In addition,reflecting the photocatalytic air purifier VOCs removal performance in the actual environment is of great theoretical and practical significance for improving IAQ and developing PCO technology.Based on PCO reaction principle and numerical simulation,a new type of photocatalytic air purification device was developed,which focused on the degradation of indoor formaldehyde by PCO technology.With formaldehyde as the target pollutant and Ti O2as the photocatalyst,three factors affecting the photocatalytic reaction:catalyst load,VOCs concentration and air flow rate were analyzed by orthogonal experiment.The effects of different purification methods to improve IAQ were compared and analyzed,and the use strategy of the reactor was discussed.The main conclusions of this paper are as follows:（1）Combined with Fluent,the photocatalytic reactor was designed and optimized,and the error between simulation and experimental results were compared.The overall error was less than 20%,which indicated that it is highly feasible to study the PCO reaction process by numerical simulation.（2）The clean air delivery rate is selected as the photocatalytic performance evaluation index in this paper.According to the orthogonal experimental results and data analysis,the primary and secondary order of factors affecting the performance of baffled wall-mounted photocatalytic reactor are:gas flow rate,initial formaldehyde concentration and photocatalyst loading.The optimal combination level of the three influencing factors is A1B2C2,which means:the loading of P25 Ti O2 is 1 mg/cm2,the initial concentration of formaldehyde is 0.8mg/m3,and the air flow rate is 1.4 m/s.（3）Under the optimal matching level,the purification energy efficiency of the baffled wall-mounted photocatalytic reactor is 0.56 m3/W·h.When the two reactors share the combination of ultraviolet lamps,the reactorηis 0.93 m3/W·h,which is close to the high-efficiency air purifier,and the purification energy efficiency is significantly improved.The photocatalytic reactor designed in this paper has high application value and research significance.（4）The comparative analysis shows that the self-designed baffled wall-mounted photocatalytic reactor has better performance in degrading formaldehyde than the traditional flat plate type,and the setting of the guide plate is beneficial to the photocatalytic reaction.The analysis showed that the formaldehyde degradation efficiency of the traditional plate reactor was 34.94%,while that of the non-direction flow reactor was 61.84%,an increase of26.9%.While the addition of the reactor after the baffle,the degradation efficiency of formaldehyde was further improved,reaching 75.32%.（5）The purification effect of different purification methods in air-conditioned rooms is studied,and the use strategy of a photocatalytic reactor is given based on numerical simulation.The results showed that:When upgrading IAQ,introducing fresh air by the fresh air system or using a photocatalytic reactor should give priority to buildings with certain requirements for temperature and humidity;For rooms without temperature and humidity requirements,the natural ventilation should be preferred.In an air-conditioned room,when the operating energy consumption of the photocatalytic reactor is less than the energy consumption generated by the introduction of fresh air purification,the technical advantages of the PCO reactor to improve IAQ can be reflected. |
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