Abstract: Based on the Tanks 4.0.9d model published by US EPA, the paper quantitatively studied the emission characteristics and influence factors on VOCs emission from the storage tank. The difference between the measured data and the model calculation results was analyzed. The results showed that the emissions of storage tanks were affected by tank structural characteristics, environmental factors, and operating conditions. The emission of the internal floating roof tank was the smallest, and the emission of the fixed roof tank was 110.5 times that of the former tank. The reduction of the tank emission could be realized by measures of painting the outer wall of the tank with white primer, regularly spraying water, installing heat insulation baffle, using anti-rust and anti-corrosion coating on the inner wall of the tank, and using LDAR (leak detection and repair) technology to regularly and quantitatively check the leakage of storage tank and repair them in time. It was found that the measured data of internal floating roof gasoline tank was 3.5 times that calculated by the model, showing that the emission from field monitoring was higher than that of calculation by the model. There are limitations in both actual measurement and model calculation. It is suggested that developing new optimized calculation softwares are of great necessity based on the domestic situation.

Key words: storage tank, VOCs emission, Tanks 4.0.9d, emission calculation methods