Effect of VOCs treatment in the methanol tank farm

The recovery and treatment of volatile gases as well as trace amounts of methyl formate, dimethyl ether, ethylene glycol, etc., from crude methanol is a complex process that involves multiple steps and technologies. The following is a detailed explanation of this process: 1. Recovery and treatment of volatile gases. For the volatile gases present in crude methanol, common recovery methods include condensation, absorption, and adsorption. Condensation method: Gaseous volatile organic compounds are converted into a liquid state by lowering the temperature or increasing the system pressure, thereby separating them from the gas. The condensation method is suitable for volatile organic compounds with high concentrations and high boiling points. For low-concentration volatile gases, due to the high energy consumption associated with low temperature and high pressure as well as the high operating costs of the equipment, the condensation method is generally not used alone for treatment; instead, combined processes are employed. Absorption method: Utilizing solutions or adsorbents to absorb methanol and other volatile organic compounds. Common absorbents include water and organic solvents. The solution after absorption can be used to separate methanol and organic compounds from it through evaporation or heating, followed by further processing or recycling. Adsorption method: This approach uses porous solid adsorbents such as activated carbon, silica gel, and molecular sieves to treat organic waste gases. By means of chemical bonding forces or molecular attraction, harmful components are effectively adsorbed onto the surface of the adsorbents, thereby achieving the purification of organic waste gases. The adsorption method is suitable for the purification of organic waste gas with high flow rates and low concentrations. II. Recovery and treatment of methyl formate: Methyl formate has relatively low volatility in methanol, so it can be separated through distillation. The distillation method takes advantage of the difference in boiling points between methyl formate and methanol, separating methyl formate from methanol through heating and condensation processes. Furthermore, the adsorption method can also be used to remove methyl formate from methanol, by using a fixed-bed adsorbent to absorb and separate methyl formate. III. Recovery and treatment of dimethyl ether: Dimethyl ether is a by-product of the methanol purification process, and its economic value can be increased through recovery and reuse. Methods for recovering dimethyl ether include condensation, absorption, and adsorption. Among them, the condensation method is one of the most commonly used approaches; it involves lowering the temperature to cause dimethyl ether to condense from the exhaust gases into a liquid state, which can then be further processed or recycled. IV. Recovery and treatment of ethylene glycol Ethylene glycol is an important chemical raw material, and trace amounts of it may be present in crude methanol. For the recovery and treatment of ethylene glycol, methods such as distillation, extraction, or adsorption can be employed. Distillation utilizes the difference in boiling points of ethylene glycol and methanol for separation ； The extraction method utilizes the selective extraction of ethylene glycol by a solvent for separation ； The adsorption principle utilizes porous adsorbents to adsorb and separate ethylene glycol. V. Comprehensive recovery and treatment process: In practical applications, in order to more effectively recover and treat the volatile gases present in crude methanol, as well as trace amounts of methyl formate, dimethyl ether, ethylene glycol, etc., a comprehensive recovery and treatment process is generally employed. This process combines various recovery methods, such as condensation, absorption, adsorption, and distillation, to achieve the effective separation and recovery of different components. In summary, the recovery and treatment of volatile gases as well as trace amounts of methyl formate, dimethyl ether, ethylene glycol, etc., in crude methanol is a complex and important process. By selecting appropriate recovery methods and process parameters, the effective separation and recovery of these components can be achieved, thereby improving resource utilization and economic benefits.