Halogenated hydrocarbon waste gas treatment technology, membrane condensation recovery, safe alternative to high temperature combustion

Haloalkanewaste gas treatmentTechnology: membrane condensation recovery, safe alternative to high temperature combustion

Halogenated hydrocarbon waste gas (dichloromethane, chloroform, chlorobenzene, etc.) is a difficult problem in the chemical and pharmaceutical industries. The particularity of this kind of exhaust gas is that it is easy to produce dioxin and other highly toxic by-products under high temperature of combustion method;activated charcoalAdsorption saturation is fast, carbon exchange is frequent, saturated carbon as a hazardous waste disposal cost is not low. The membrane condensation recovery process provides a technical route for physical separation, which avoids the safety risk of combustion method from the source.

Process Principle

The process uses a combination of "compression condensation membrane separation. The exhaust gas is first compressed and pressurized, and then enters the condensing unit. Most of the halogenated hydrocarbons are directly liquefied from gaseous to liquid under low temperature conditions, and can be directly reused for production after collection. The condensed tail gas enters the membrane separation unit, and by taking advantage of the difference in permeation rate between halogenated hydrocarbon molecules and air molecules in the membrane material, halogenated hydrocarbons preferentially permeate the membrane layer to form concentrated gas, which is sent back to the front end of the system for circulating treatment. The whole system operates in closed circuit.

Security is the biggest difference.

Membrane separation is pure physical separation, the whole process does not involve combustion, no open flame, from the source to avoid the risk of dioxin. For halogen-containing waste gas, this difference is fundamental-the combustion method faces the double hidden dangers of dioxin emissions and hydrogen chloride corrosion, and physical separation does not have these problems.

Economic benefits

Compared with the traditional cryogenic technology, the combined process can reduce the energy consumption by about 60%, and the solvent recovery rate can reach more than 95%. The concentration of recovered halogenated hydrocarbons is higher than 90%, which can be directly reused in the production line, reducing the cost of raw material procurement. The equipment has no active carbon consumables and no hazardous waste. The daily maintenance is mainly to clean up the heat exchanger and check the pressure difference of the membrane module. The process can recover aromatics, alkanes, alkenes, halogenated hydrocarbons, alcohols, esters, ketones, ethers and other organic substances.

For halogenated hydrocarbon waste gas, membrane condensation recovery is a mature choice to realize solvent resource utilization under the premise of ensuring safety. It is recommended to complete the working condition test before selection, and match the process parameters according to the concentration, composition and air volume.