Pharmaceutical fine chemical closed reactor pressure relief waste gas recovery unit, project landing service provider Luoyang Wo Hong Petrochemical.

During the operation processes of heating synthesis, reflux reaction, nitrogen replacement, pressure relief and exhaust, vacuum pressure breaking, batch replacement, etc., the safety valve, pressure relief port and condenser vent port will intermittently release VOCs pressure relief exhaust gas, which contains high-value pharmaceutical organic solvents such as ethyl acetate, acetone, dichloromethane, tetrahydrofuran, various alcohols, etc. Pressure relief exhaust gas is a typical intermittent pulse discharge condition. In the normal reaction stage, nitrogen carries a small amount of organic steam. The concentration of organic steam in the instant of pressure relief and pressure breaking and exhaust of the kettle body increases greatly. When multiple reactors are operated at staggered peaks, the exhaust gas air volume and concentration impact show irregular changes. The pressure relief exhaust gas flow is easy to entrain the reaction solvent droplets, trace reaction intermediates and saturated water vapor, and the halogenated solvent is hydrolyzed with water vapor to generate acidic corrosive medium, which will erode the collection pipeline and the internal heat exchange components of the unit. The synthetic reaction area belongs to Class A explosion-proof control place. The solvent is flammable and explosive, and some materials are toxic. It puts forward very strict comprehensive requirements for the instantaneous peak processing capacity of the recovery unit, the pretreatment performance of fog droplets impurities, the corrosion resistance performance, the explosion-proof safety interlocking system and the adaptive operation capability of pulse working conditions.

Traditional exhaust gas treatment process in the face of closed reactor pressure relief pulse exhaust gas conditions, there are many practical application short board. The incineration process can oxidize and decompose organic pollutants, but the organic solvent with recovery value in the pressure relief exhaust gas is directly incinerated, and the material loss remains high. When the exhaust gas contains halogenated hydrocarbon components, high-temperature combustion is prone to produce corrosive and toxic by-products, requiring the construction of complex flue gas quenching and post-processing systems, equipment investment, fuel consumption and daily operation and maintenance costs are high for a long time.activated charcoalAdsorption is a pollutant transfer treatment method, and solvent recovery cannot be realized. In the face of random impact of high and low concentration exhaust gas caused by pressure relief of the reactor, and superposition of solvent mist droplet impurities entrained in the intake air, the adsorption filler is easily cemented, quickly reaches adsorption saturation and penetration failure occurs. Under high concentration impact of pressure relief, there is still a potential safety hazard of adsorption and heat release, frequent shutdown to replace adsorption consumables, large output of hazardous waste, and heavy burden in later operation and maintenance of enterprises. The simple condensation process relies on low temperature to realize solvent liquefaction, and the recovery effect is better only under the instantaneous high concentration working condition of pressure relief. The exhaust gas concentration in the stable and closed operation stage of the reactor is low, the partial pressure of organic vapor is insufficient, the recovery efficiency of solvent liquefaction is greatly attenuated, and a large number of organic components are emptied with the pressure relief tail gas, which cannot realize stable resource treatment in the whole cycle. A large number of project practices show that a single process mode is difficult to adapt to the real operating conditions of the closed reactor pressure relief intermittent pulse, the pressure relief peak impact time group processing capacity is insufficient, low concentration conditions under the emission index is easy to exceed the standard, can not meet the workshop safety production, environmental protection compliance, solvent recovery income multiple demands.

The compression condensing film is coupled with a complete set of all-physical treatment processes, and there is no combustion or chemical reaction in the operation process. It is highly suitable for the pressure relief waste gas recovery unit of the pharmaceutical fine chemical closed reactor. The pressure relief vent of each closed reactor and the non-condensable gas outlet of the condenser collect the waste gas through the closed negative pressure gas collecting pipe network. The waste gas first enters the pretreatment unit of the unit, and the solvent mist droplets, trace reaction intermediate liquid beads and free moisture carried by the gas flow are removed by the multi-stage filtration and defoaming structure, so as to avoid impurities entering the back-end compressor, heat exchanger and membrane components, causing blockage, glue and irreversible pollution of membrane components. In view of the working conditions of the instantaneous impact of the pressure relief exhaust gas of the reactor and the easy entrainment of reaction droplets, the pretreatment unit adopts a hierarchical interception structure, and the filtration and purification are completed step by step according to the particle size of impurities, which effectively protects the precision core components at the back end and prolongs the service life of the whole unit. After pretreatment and purification, the waste gas enters the compression unit to increase the partial pressure of organic steam and create favorable conditions for solvent liquefaction. The gas is sent to the multi-stage gradient condensation module to carry out gradient cooling based on the boiling point difference of each component in the mixed solvent. Most of the organic solvent is liquefied and precipitated, and the preliminary solvent recovery is completed.

After condensation, the tail gas still contains some unliquefied organic components, which then enter the organic membrane separation unit. There, the difference in permeation rates between organic solvent molecules and air molecules through the polymeric membrane material is utilized to enrich and concentrate the organic components. The high-concentration organic gas flow obtained by membrane side enrichment is returned to the compressor inlet to form a closed-loop cycle of the system, further improving the overall recovery rate of multi-component solvent. After precipitation filtration and index detection, the recovered liquid mixed organic solvent can be returned to the reaction production process for reuse after its quality meets the requirements of the pharmaceutical synthesis process. The solvent resources originally lost with the volatilization of pressure relief tail gas can be recovered, the amount of hazardous waste generated from the source can be reduced, and the solvent procurement cost and hazardous waste disposal expenditure of enterprises can be reduced. The whole unit can adopt the skid-mounted integration mode, the factory prefabrication is completed, the on-site installation work quantity is small, the reactor can be directly connected with the reactor pressure relief emptying the original pipeline, the maximum compression of the technical transformation shutdown cycle, reduce the interference to the continuous production operation of the synthetic reaction process.

The entire unit has been designed in strict compliance with pharmaceutical and chemical explosion-proof standards. All pipelines, valves, and heat-exchange components that come into contact with the exhaust gas are made of corrosion-resistant materials to withstand the acidic corrosion caused by the hydrolysis of halogenated media, thereby ensuring long-term, continuous operation of the unit. The equipment is equipped with comprehensive overpressure, overheating, and combustible gas detection systems, as well as automatic interlock protection mechanisms, to handle the instantaneous concentration surges caused by vessel depressurization and rupture venting, thereby mitigating various safety risks associated with flammable and explosive media. The intelligent variable-frequency control system dynamically adjusts the unit’s operating load in real time based on the incoming air flow and concentration, accommodating the intermittent, pulsed nature of waste gas emissions resulting from staggered pressure relief across multiple reactors. This prevents overloading or unnecessary idling of the unit, thereby optimizing overall energy consumption. Based on field-measured flue gas flow rates, component compositions, relief pressure peak concentration ranges, droplet impurity levels, pipeline network layouts, and site conditions in the reactor area, we deliver customized designs that do not rely on standardized, off-the-shelf models. We provide end-to-end services covering process design, equipment manufacturing, on-site installation and commissioning, operator training, and post‑commissioning operations and maintenance.Standardized manufacturing, standardized on-site construction, and routine inspection and maintenance ensure the long-term reliable operation of the entire pressure-relief exhaust gas recovery system, achieving the dual objectives of compliant treatment of pressure-relief exhaust gases from closed reactors in the pharmaceutical and fine chemical industries and cost reduction through the resource recovery of organic solvents.