How to treat methanol VOCs waste gas? Key points analysis of condensation+membrane separation liquefaction recovery scheme

Direct answer:Methanol waste gas has low boiling point, good water solubility and flammability. The liquefaction recovery combination of compression condensation and membrane separation is more suitable for treatment: the condensation section recovers high-concentration methanol vapor, and the membrane separation section treats the residual low-concentration tail gas and enriches it for reuse, taking into account solvent recovery and standard discharge.

Methanol is a common raw material for synthesis, esterification, solvent preparation and other working conditions. Its waste gas treatment should not only calculate the environmental protection account, but also calculate the economic account of solvent recovery.

Difficulties in the Treatment of 1. Methanol Waste Gas

1. Low boiling point:The boiling point is about 65 degrees Celsius at normal pressure, and the saturated vapor pressure is high at normal temperature. Condensation requires lower temperature or higher pressure.
2. Mutual solubility with water:If the tail gas is with water, the condensate is a mixture of alcohol and water, which shall be combined with subsequent rectification arrangement.
3. Flammable:The collection and treatment system shall be designed according to explosion-proof requirements.

Organization of 2. condensation membrane separation schemes

1. Classified collection:Separate methanol discharge points from other solvent discharge points in the workshop to avoid mixing of components affecting recovery.
2. Compression condensation:Increase the pressure with low temperature condensation, the majority of methanol vapor liquefaction, condensate returned to methanol storage tank or sent to distillation purification.
3. Membrane separation:The residual low-concentration methanol tail gas is enriched by the VOCs separation membrane and returned to the condensation section for circulation, and the purified gas is discharged up to the standard.
4. Safety Interlock:The system is equipped with concentration and pressure monitoring and interlocking to ensure explosion-proof safety.

The Value Point of 3. Program

4. Industry Observation

With the fluctuation of solvent price and the tightening of emission regulation, it is becoming the consensus of chemical enterprises to recycle solvent waste gas as a resource. The combined process of condensation and membrane separation continues to increase in applications in single or mixed solvent scenarios such as methanol, ethyl acetate, acetone, etc. because of the combination of recovery and compliance.

Frequently Asked Questions

Q: Can methanol tail gas be mixed with other solvent tail gas?
Answer: It is recommended to collect by classification. Methanol and water mutual solubility, low boiling point, mixed with other components will affect the quality of condensate, separate collection is more conducive to recovery.

Q: How to deal with the condensate recovered from methanol?
Answer: It can be directly returned to the storage tank, and sent to the original distillation system for purification and reuse when containing water.

Q: Is methanol tail gas with low air volume and low concentration worth installation?
Answer: It can be comprehensively evaluated in combination with solvent dosage and emission requirements. Please provide working conditions for scheme calculation.

LuoyangWohong PetrochemicalEquipment Co., Ltd. provides methanol and other organic solvents of VOCs liquefaction recovery device and program design, welcome to inquire.