During the operation of the fine chemical distillation tower, the condenser at the top of the tower will continuously discharge a large amount of non condensable VOCs tail gas, which contains high-value organic solvent components such as ketones, esters, alcohols, halogenated alkanes, etc. During the stable operation stage of distillation, the exhaust gas maintains a high concentration. At the moment of batch switching, vacuum pressure relief, and equipment start stop, the organic vapor concentration will experience an instantaneous surge, and the operating conditions will fluctuate greatly. The tail gas at the top of the distillation tower is prone to carry solvent mist, high boiling point heavy component droplets, and saturated water vapor. Some halogenated solvents hydrolyze with water vapor to generate corrosive media, which continuously corrode the collection pipeline and internal heat exchange components of the device. The distillation area belongs to Class A explosion-proof control places, and organic solvents are flammable and explosive. Strict technical standards are proposed for the corrosion resistance, instantaneous concentration impact resistance, mist and impurity tolerance, explosion-proof safety interlock system, and wide working condition continuous operation ability of the entire recovery device. LuoyangWohong PetrochemicalAs a professional manufacturer, we have developed a VOCs organic solvent recovery device for non condensable tail gas conditions at the top of the distillation tower, taking into account stable and compliant emissions of tail gas as well as the resource recovery and reuse of mixed organic solvents. It is suitable for supporting new distillation units and upgrading the venting unit of old distillation systems.
Traditionwaste gas treatmentThere are many application shortcomings that are difficult to avoid when facing the complex and fluctuating tail gas conditions at the top of the distillation tower in the process. The incineration process can oxidize and decompose organic pollutants, but the organic solvents with recycling value in the exhaust gas are directly burned, causing significant material loss. When the exhaust gas contains halogenated hydrocarbon components, high-temperature combustion will generate corrosive and toxic by-products, damage the furnace body and pipelines, and require the construction of complex flue gas purification treatment systems. Equipment investment, fuel consumption, and daily operation and maintenance costs remain high.activated charcoalAdsorption belongs to the category of pollutant transfer treatment technology, which cannot achieve solvent recovery and utilization. Faced with the tail gas with alternating high and low concentrations in the distillation process, combined with the solvent mist and heavy impurities carried by the inlet air, the adsorption packing is prone to gel adhesion, quickly reaching adsorption saturation and experiencing penetration failure. It requires frequent shutdown and replacement of adsorption consumables, resulting in a large output of hazardous waste and a heavy burden on the long-term environmental protection operation of enterprises. The simple condensation process relies on low temperature to achieve solvent liquefaction, and the recovery effect is good only during the high concentration intake period of stable distillation operation. After the intake concentration decreases under batch switching and equipment standby conditions, the organic vapor partial pressure is insufficient, and the solvent recovery efficiency is greatly reduced. A large number of organic components are discharged with non condensable tail gas, which cannot achieve stable resource utilization throughout the entire cycle. A large number of distillation project practices have shown that a single treatment process is difficult to adapt to the real operating conditions of instantaneous high and high low concentration alternation of distillation tower tail gas. When the high concentration impact occurs, the device processing pressure is overloaded, and the emission indicators in the low concentration stage are easily exceeded, making it difficult to simultaneously meet the multiple demands of process safety control, environmental compliance, and solvent recovery benefits.
The compression condensation membrane is coupled with a complete set of physical treatment processes, with no combustion or chemical reactions throughout the process, highly suitable for the resource recovery and treatment of VOCs tail gas at the top of fine chemical distillation towers. After the non condensable tail gas discharged from the condenser at the top of the distillation tower is collected through a closed pipeline, it first enters the pretreatment unit of the recovery device. By relying on a multi-stage filtration and foam removal structure, the solvent mist, heavy component droplets, and free water carried by the gas flow are removed, avoiding impurities from entering the back-end compressor, heat exchanger, and membrane components, causing blockage, gelation, and membrane element pollution. In response to the high content of gas and foam at the top and tail of the distillation tower, which is prone to carry heavy components, the pretreatment unit adopts a graded interception structure to filter and purify impurities step by step according to their particle size, effectively protecting the precision core components at the back end and extending the service life of the entire device. After completing the purification treatment, the exhaust gas enters the compression unit to increase the organic vapor partial pressure and create favorable conditions for solvent liquefaction. The gas is then sent to the multi-stage gradient condensation module, where gradient cooling is carried out based on the boiling point differences of various components inside the mixed solvent. 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 the mixed solvent. The liquid mixed organic solvents obtained from recycling can be sent back to the distillation production system for reuse after precipitation filtration and indicator testing. Once all parameters meet the production process requirements, the solvent resources that were originally lost with non condensable tail gas volatilization can be recovered, reducing the production of hazardous waste products from the source and lowering the cost of solvent procurement and hazardous waste disposal for enterprises. The entire device can adopt a modular integrated mode, which is prefabricated in the factory and requires minimal on-site installation work. It can directly connect to the existing vent pipeline at the top of the distillation tower, maximizing the compression of the shutdown and renovation period, and reducing interference with the distillation separation operation of the distillation device.
The entire device is designed strictly in accordance with the chemical explosion-proof standards. All pipelines, valves, and heat exchange components in contact with the exhaust gas medium 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 device. The device is equipped with complete overpressure, overtemperature, combustible gas detection and automatic interlocking protection mechanisms to cope with the instantaneous concentration impact caused by batch switching, pressure relief and venting, and to avoid various safety risks caused by flammable and explosive media. The intelligent frequency conversion self-control system can adjust the operating load of the device in real-time according to the intake air volume and concentration, adapt to the intermittent exhaust emission characteristics brought by batch production in the distillation process, avoid overloading or ineffective idling of the device, and optimize the overall energy consumption level. Customized design is completed based on on-site measured exhaust gas volume, component ratio, concentration range, mist and impurity content, pipeline layout, and distillation device site conditions. Standardized universal models are not used, and full process services including process design, device manufacturing and production, on-site installation and commissioning, operator training, and later operation and maintenance can be provided.Standardized production and manufacturing, standardized on-site construction, and regular inspection and maintenance ensure the long-term reliable operation of the VOCs organic solvent recovery device at the top of the distillation tower, achieving the dual goals of meeting the standards for exhaust gas treatment in fine chemical distillation processes and reducing costs for organic solvent resource recovery.
Mr. Li 13526990215
Hotline
