| In recent years,as China has made a series of major technological breakthroughs in the related industries of electronic manufacturing,China has become the largest production base of liquid crystal display in the world.In thin film transistor liquid crystal display(TFT-LCD)manufacturing industry,there are many new occupational health problems,especially organic matter in photolithography.The main components of some organic compounds are not stipulated in their occupational exposure limits,there is no relevant occupational health testing methods,and even the relevant toxicological studies are relatively few.Factories smell everywhere,causing employees to worry about the impact of these organic substances on their health.Therefore,it is meaningful to study the occupation health problems of TFT LCD.In this paper,the numerical simulation method is used to study the organic gas dispersion law in the TFT-LCD manufacturing industry,the ventilation effect and the optimization index of the ventilation system.The research objection is a famous film TFT-LCD manufacturer in China.The three-dimensional geometric model was established by the software fluent,and the numerical simulation of the ventilation effect under the conditions of different exhaust air volume and air outlet area was simulated.The velocity field and concentration field distribution of propylene glycol methyl ether acetate(PGMEA)diffusion are analyzed.The results of the study are as follows:(1)In the absence of design of ventilation system,airtight cover external z=0m section propylene glycol ether acetate mainly gathered in the 0<x<4.2(closed cover gap length)of the Y axis range,and with the increase of the distance and gap,propylene glycol ether acetate to gather near the center;The concentration of V1 point in the gap is 141.47mg/m~3,and the concentration of V2 is 94.34mg/m~3.The concentration range of v3-v6 point is 32.09mg/m~3-13.34mg/m~3(The v3-v6 point is located outside the airtight cover,and the inspectors often go through the breathing height of the location.)The larger the distance from the gap to the closed cover,the lower the concentration.(2)In the case of the same exhaust air volume,When the exhaust volume is8000m~3/h,1000 m~3/h,12000 m~3/h and 14000 m~3/h,The reasonable air outlet area can improve the uniformity of the air flow,reduce the eddy current and improve the ventilation effect.When the ventilation quantity,different outlet area,the concentration of PGMEA was similar in airtight cover changes in the distance along the way,the airtight cover gap 4m v6 point was the highest,at a distance of 1m at the v4 point closed cover of low concentration,airtight cover and international v3,v4,v5,v6 the air outlet width is 1.0m,the concentration of PGMEA decreased to the lowest.(3)The increase of exhaust air volume can accelerate the discharge of the volatile gas of PGMEA,reduce the aggregation of the volatile gas of the propylene glycol methyl ether acetate,and reduce the diffusion range.With the increase of exhaust air volume,the concentration of propylene glycol methyl ether acetate on the z=1.5m section gradually decreased,and the pollution area gradually decreased.The concentrations of v3,v4,v5 and V6 outside the airtight cover decrease.(4)Through the analysis of the diffusion of harmful gas in the exhaust air exhaust system,it is found that the 1m wide airflow outlet is set at the bottom of the closed cover,the discharge volume is 14000m~3/h,and the concentration of the propylene glycol methyl ether acetate in the closed cover is almost zero.After optimization,the discharge rate of propylene glycol methyl ether acetate increased significantly,the diffusion area outside the airtight cover decreased significantly,and the concentration of propylene glycol methyl ether acetate decreased.So this working condition can discharge harmful gas centrally when meeting the requirement of process conditions,and will not spread to the whole workshop. |
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