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I. Introduction to the basic data for VOCs control in the methanol intermediate tank area: In the methanol production process, the intermediate tanks include pure alcohol tanks, crude alcohol tanks, and miscellaneous alcohol tanks. The pure alcohol tank serves as a storage tank for the finished methanol; the purified methanol coming out of the distillation tower during production is first stored in this tank, and after 8 hours, the finished methanol is pumped into the final product tank. Due to the early construction of this plant, all the intermediate tanks are dome-shaped tanks; during the filling process, a high concentration of methanol is released along with the gas, which is what is known as \"large breathing\"” ； During the fluctuations in day-night temperature differences, methanol also volatilizes and is released into the atmosphere through the breathing window, a phenomenon known as \"minor breathing\". In accordance with the emission standards related to organic substances as well as the requirements outlined in Sinopec’s Document No. 127, storage tanks containing triphenyl compounds and methyl A compounds need to have their VOC emissions from both \"major\" and \"minor breathing\" processes controlled. As required by Letter No. 127, first the breathing window must be sealed; second, the breathing gas must be led down from the top of the tank, a single-exhaust valve system shall be used, and a nitrogen seal shall be installed in the storage tank system to ensure its safety. http://www.gxhjtc.com/uploads/180711/1-1PG1224S5429.png II. Components of the exhaust gas from the methanol intermediate storage tanks: The main VOCs emitted from the pure methanol tanks are methanol, while the exhaust gas from the crude methanol tanks contains methanol, dimethyl ether, and other substances. The tanks holding mixed alcohols contain mainly formaldehyde, monomethylamine, dimethylamine, trimethylamine, acetaldehyde, methyl formate, pentane, propanal, ethyl formate, and other compounds. III. Treatment processes for methanol VOCs: For the vent gases from storage tanks, common treatment methods include pressure swing adsorption (PTA), condensation, and condensation + pressure swing adsorption ； However, given the complex composition of the crude alcohol tanks and other related tanks in the methanol intermediate tank area, the recovery method is not suitable; therefore, the water absorption + activated carbon adsorption process is more appropriate for this project. The VOCs exhaust gas first passes through a water absorption tower, where methanol is absorbed into the water, and then enters an activated carbon adsorption unit. The rich liquid resulting from absorption in the absorber is pumped into the distillation tower for further distillation, while the activated carbon can be sent to a sintering plant for combustion. http://www.gxhjtc.com/uploads/180711/1-1PG1224923D9.png V. Conclusion: The VOC emissions from the methanol intermediate tank area meet the required standards after treatment. No secondary pollution is generated. The most important thing is that the safety of the tank area is ensured. Regarding nitrogen sealing, subsequent modifications to the tank area will inevitably affect the plant’s production. Welding is not allowed in the tank storage area, and it is even more prohibited to weld on the tank bodies themselves. Therefore, when implementing nitrogen sealing, these two factors must be taken into account, which adds complexity to the actual work. The above is for reference only. The above article is from the official website of Beijing Shared Environment Engineering Co., Ltd. at www.gxhjtc.com