Numerical Simulation Of Formaldehyde In A Wood-based Panel Production Department And Health Assessment

Along with the rapid development of economy, the demand of construction industry, interior decoration industry, et al, for wood-based panel is rapidly growing, all kinds of wood-based panel production increase sharply year by year. As there are large amounts of VOC generated during the wood-based panel processes, the air quality in the production department is bad, some test results show that the air pollutants are far more unacceptable in the production department, and formaldehyde concentration exceed 6 times of the standard value. In order to study the ventilation effect on the distribution of formaldehyde concentration in the department, in this paper, commercial CFD software is used to simulate a certain wood-based panel production department in China.In this paper, the combination research methods of field testing, investigation and CFD was adopted. The simplified physical model had been obtained by field testing and survey; the boundary conditions of the model were confirmed by testing formaldehyde concentration, air temperature, humidity, wind speed, mat surface temperature. As the department is divided into some zones, the two step simulation method was adopted to solve the problems that the CFD can only simulating one zone at a time.The department is for the hot-pressing process, there are two sets of exhaust systems composing the entire exhaust system, a large number of VOC are generated in hot-pressing section, so formaldehyde concentration here is the highest in the department, thus a local exhaust system is fixed here, while another ventilation system installed in the department roof.Panel rated production rate is 30m3/h, assuming, the production rate reduce to 22.5 m3/h,15m3/h,7.5m3/h in turn.In this paper, the two following situations were simulated:1. Panel production rate gradually decreased, while air volume of the local exhaust ventilation system and the roof exhaust system remained unchanged; 2. Panel production rate was gradually reduced, and the roof exhaust system air volume did not vary, on the premise of that the air quality of the department did not decrease, then reduced the air volume of the exhaust system.Simulation 1 results show that:With the production rate decline, the average formaldehyde concentration in hot-pressing section and the main work area decrease, but the rate of formaldehyde decline is less than the rate of production decrease; the same time the proportion of formaldehyde removed by local exhaust decrease, correspondingly, the proportion of formaldehyde removed by the roof exhaust system increase gradually.Simulation 2 results show that:when the production rate is 22.5m3/h, in order to ensure that the indoor air quality in department is good, air volume of local exhaust system should not be reduced; when the production rate is 15m3/h, by reducing air volume of the local exhaust system, can make the entire exhaust system achieving the energy saving rate of 39.5%; when the production rate of 7.5m3/h, by reducing air volume of the local exhaust system, can make the entire exhaust system achieving the energy saving rate of 65.52%.According to the simulation results, when the production rate decline, on the premise of that the air quality of the department does not decrease, by reducing the air volume of the exhaust system, so as to achieve energy saving.