The vacuum desolvation process of pharmaceutical fine chemicals mainly includes operations such as raw material concentration, solvent evaporation, double cone drying, three in one filtration, washing and drying, and vacuum distillation desolvation. The exhaust port of the vacuum pump continuously discharges a large amount of VOCs exhaust gas, and the exhaust gas components include high-value pharmaceutical solvents such as dichloromethane, ethyl acetate, acetone, tetrahydrofuran, methanol, isopropanol, etc. Vacuum desolvation belongs to a typical intermittent negative pressure working condition, with a large amount of solvent evaporation in the early stage of desolvation, and the exhaust concentration of the vacuum pump is at a high level; The solvent content of the material decreases in the later stage of desolvation, and the concentration of exhaust gas rapidly decreases; There will be concentration pulse impact during batch switching and pressure recovery stage, and the entire process has a large range of exhaust gas concentration and significant fluctuations in gas volume. The exhaust gas flow is prone to carry solvent droplets, trace material aerosols, and saturated water vapor. Halogenated solvents hydrolyze with water vapor to generate acidic corrosive media, which can corrode the back-end pipelines and equipment heat exchange components of the vacuum pump. The vacuum dissolution section belongs to Class A explosion-proof control area, where the medium is flammable and explosive, and some materials are toxic. Strict technical requirements are put forward for the aerosol and droplet pretreatment ability, wide concentration range adaptability, pulse impact resistance, corrosion resistance, explosion-proof interlock protection system, and negative pressure intake working condition adaptability of solvent recovery and treatment equipment.
There are many practical application shortcomings in the use of traditional exhaust gas treatment processes for vacuum desolvation exhaust gas conditions. The incineration process can oxidize and decompose organic pollutants, but high-value organic solvents in the exhaust are directly burned, resulting in high material loss costs. When the exhaust gas contains halogenated components such as dichloromethane, high-temperature incineration can easily generate hydrogen chloride and toxic by-products, leading to severe equipment corrosion. Complex quenching, desulfurization, and denitrification post-treatment systems also need to be built, resulting in long-term high equipment investment, fuel consumption, and daily operation and maintenance costs.activated charcoalAdsorption is a pollutant transfer treatment method that cannot achieve solvent resource recovery. Faced with the high and low concentration fluctuations of exhaust gas in the vacuum desolvation process, combined with solvent droplets and aerosol impurities carried by the intake air, the adsorption packing is prone to gel and plate formation, quickly reaching adsorption saturation and causing penetration failure. High concentration impact conditions also pose safety hazards for adsorption heat release, requiring frequent shutdown and replacement of adsorption consumables. The output of hazardous waste is large, and the burden of enterprise operation and maintenance is heavy. The simple condensation process relies on low temperature to achieve solvent liquefaction, and the recovery effect is better only in the high concentration exhaust stage in the early stage of desolvation. In the late stage of desolvation, the organic vapor partial pressure under low concentration conditions is insufficient, and the solvent liquefaction recovery efficiency is greatly reduced. A large number of organic components are directly discharged with the exhaust gas of the vacuum pump, making it impossible to achieve stable resource utilization throughout the entire cycle. A large number of project practices have shown that a single process mode is difficult to adapt to the real working conditions of wide concentration and intermittent pulse of vacuum desolvation exhaust gas. The equipment processing capacity is insufficient at the peak exhaust time of desolvation, and the emission indicators in the low concentration range in the later stage of desolvation are prone to exceed the standard, which cannot simultaneously meet the multiple demands of workshop safety production, environmental compliance, and solvent recovery cost reduction.
The compression condensation film is coupled with a complete set of physical processing technology, which operates without combustion or chemical reactions, and is highly suitable for pharmaceutical and fine chemical vacuum desolvation tail gas solvent recovery treatment equipment. The exhaust port of the vacuum pump of each vacuum dissolution equipment collects the exhaust gas through a closed negative pressure gas collection network. The exhaust gas first enters the equipment pretreatment unit, and uses a multi-stage filtration and foam removal structure to remove solvent droplets, material aerosols, and free moisture carried by the airflow, avoiding impurities from entering the back-end compressor, heat exchanger, and membrane components, causing blockages, adhesives, and irreversible pollution of membrane components. In response to the characteristics of significant aerosol entrainment and large fluctuations in working conditions in vacuum desolvation exhaust gas, the pretreatment unit adopts a graded interception structure to purify impurities step by step according to their particle size, effectively protecting the precision core components of the back-end and extending the service life of the entire equipment. After completing pre-treatment and purification, the exhaust gas enters the compression unit to increase the organic vapor partial pressure, change the gas-liquid phase equilibrium conditions, and create favorable conditions for solvent liquefaction. The gas is sent to the multi-stage gradient condensation module, and gradient cooling is carried out based on the boiling point differences of various solvents. Most of the organic solvents liquefy and precipitate, completing the preliminary solvent recovery work.
After condensation treatment, the exhaust gas still retains some un liquefied organic components, which enter the organic membrane separation unit. With the help of polymer membrane materials, the difference in permeation rate between organic solvent molecules and air molecules is used to complete the enrichment and concentration of organic components. The exhaust gas that meets the standards is discharged to the outside, and the high concentration organic gas flow enriched on the membrane side is refluxed to the inlet of the compressor, forming a closed-loop system and further improving the overall recovery rate of various mixed solvents. The liquid mixed organic solvents obtained from recycling can be sent back to the vacuum desolvation process for recycling after precipitation, water separation filtration, and indicator testing to meet the quality requirements of pharmaceutical production processes. The solvent resources that were originally lost with the exhaust gas of the vacuum pump can be recovered, reducing the amount of hazardous waste generated from the source, lowering the cost of solvent procurement and hazardous waste disposal for enterprises. The entire equipment adopts a pry mounted integrated structure, and the factory completes the assembly, explosion-proof verification, and pressure testing of the whole machine. The on-site installation work is small, and it can directly connect to the original exhaust pipeline of the vacuum pump group, maximizing the compression of the technical transformation shutdown period and reducing the interference on the production operation of raw material vacuum desolvation.
The entire equipment is designed strictly in accordance with the pharmaceutical and chemical explosion-proof standards. All pipelines, valves, and heat exchange components that come into contact with exhaust gas media are made of corrosion-resistant materials to resist the acidic corrosion caused by the hydrolysis of halogenated media and ensure long-term continuous operation of the equipment. The equipment is equipped with complete overpressure, overtemperature, combustible gas detection, and automatic interlocking protection mechanisms to cope with the instantaneous concentration impact caused by high concentration exhaust and pressure relief gas in the early stage of desolvation, and to avoid various safety risks caused by flammable and explosive media. The intelligent frequency conversion self-control system automatically adjusts the operating load of the equipment according to changes in intake air volume and concentration, matching the characteristics of wide interval intermittent exhaust emissions in the vacuum desolvation process, avoiding equipment overload operation or ineffective idling, and optimizing the overall energy consumption level. Based on on-site measurements of exhaust gas volume, component composition, concentration fluctuation range, aerosol impurity content, pipeline layout, and workshop site conditions, customized design can be carried out without using standardized general models. We can provide full process services including on-site working condition survey, process design, equipment manufacturing and production, on-site installation and commissioning, operator training, and later operation and maintenance.Standardized production and manufacturing, standardized on-site construction, and regular inspection and maintenance ensure the long-term reliable operation of the entire vacuum desolvation tail gas solvent recovery treatment equipment, achieving the dual goals of meeting the standards for tail gas treatment in the pharmaceutical and fine chemical vacuum desolvation section and reducing costs and increasing efficiency in organic solvent resource recovery.
Mr. Li 13526990215
Hotline
