Can VOC waste gas treatment equipment handle mixed solvents? Membrane condensation is equally effective for multiple components

    VOCWaste gas treatment equipmentCan it handle mixed solvents? Membrane condensation is equally effective for multiple components

    VOCwaste gas treatmentMixing solvents is a common situation. The exhaust gases emitted from industries such as chemical, pharmaceutical, printing, and coating are often not single components, but a mixture of multiple solvents, such as toluene+ethyl acetate, dichloromethane+acetone, n-hexane+cyclohexane, and other combinations. The membrane condensation process is also applicable to multi-component mixed solvents.

The principle of membrane condensation treatment for mixed solvents is the same as that for single components. The exhaust gas first enters the condensing unit, where the temperature drops to a certain extent. The components with higher boiling points in the mixed solvent are first condensed and liquefied, while the components with lower boiling points are condensed or still exist in a gaseous state. By staged condensation or setting a reasonable condensation temperature, most components in the mixed solvent can be recovered simultaneously. The condensed mixed solvent can be collected and stored, and then separated and reused through distillation or other methods, or directly used as a mixed solvent in processes that do not require high purity.

The uncondensed exhaust gas enters the membrane separation unit. There are differences in the permeability selectivity of membrane components for different organic compounds, but membrane materials on the market have good permeability for common solvents, including aromatic hydrocarbons, alkanes, ketones, esters, halogenated hydrocarbons, etc. After the mixed exhaust gas enters the membrane module, various VOC molecules preferentially pass through the membrane layer to form concentrated gas, which is sent back to the front end of the system for circulation treatment. The air is intercepted and directly discharged. Membrane separation does not require a single component, as long as the total organic concentration is sufficient, it can be effectively separated.

From practical applications, there have been mature cases of mixed solvent recovery. The exhaust gas from the Shinao oil tank area and crude aromatic hydrocarbon tank area of Tianjin Petrochemical contains various components such as benzene, toluene, and xylene. After being treated with two-stage membrane separation coupling technology, the benzene concentration in the exhaust gas remains stable below 4 milligrams per cubic meter, toluene below 15 milligrams per cubic meter, and xylene below 20 milligrams per cubic meter, which meets national emission standards. Membrane separation is equally effective for multi-component mixed exhaust gases.

It should be noted that the influence of mixed solvents on membrane materials needs to be evaluated. The permeation behavior of different components in the membrane varies, and the interactions between components may also affect the separation efficiency. Some components with low boiling points and high permeability may carry other components through, and the overall recovery rate is often higher than the weighted average of a single component. The specific effect depends on the composition of the mixture and the matching of the membrane material.

LuoyangWohong PetrochemicalThe compression condensation membrane separation unit of Equipment Co., Ltd. can match the condensation temperature and membrane component parameters for mixed solvent exhaust gas. Enterprises with demand can first provide data on exhaust gas components, and then conduct process matching and effect evaluation.