Toluene waste gas recovery device
Core process
Condensation method: Utilize the refrigeration system to cool the exhaust gas to below the toluene dew point, causing it to liquefy and be recovered in liquid form.
Absorption method: Use organic solvents or new ionic liquids as absorbents to absorb toluene from the exhaust gas, and then separate and purify it.
Adsorption method: The most classic method. Utilize the strong adsorption capacity of porous materials such as activated carbon, zeolites, or macroporous resins to capture toluene, and after saturation, desorb it through heat media (steam, hot air, hot nitrogen) to recover high-concentration toluene.
Membrane separation method: Utilize the selective permeability of special molecular membranes to separate and concentrate toluene from the exhaust gas, and it is often used in combination with the condensation method.
Combination process and system composition
In practical applications, to improve processing efficiency and economic benefits, various technologies are usually combined:
Pre-treatment unit: Utilizes filtration and cooling devices to remove dust and reduce temperature, preparing for the subsequent processes.
Multi-stage adsorption unit: Typically, 2 to 4 adsorption vessels are designed to operate in parallel to achieve continuous and uninterrupted operation.
High-concentration gas desorption: Using low-pressure steam or inert gas, the toluene adsorbed on the saturated adsorbent is desorbed.
Condensation recovery unit: This unit conducts deep condensation on the highly concentrated gas that has been desorbed, causing it to liquefy into clean solvents.
Solvent separation and purification: Obtain high-purity toluene products through gravity stratification (in conjunction with water vapor condensation) or by using a distillation tower.
Control system: Utilizes digital and intelligent systems such as PLC to achieve automatic regulation of key parameters, process switching, and safety interlocks.
Application cost and economic benefits
Investment cost: The investment amounts for different technical routes vary significantly. When choosing, it is necessary to evaluate comprehensively based on investment and long-term returns.
Condensation + Adsorption Combined Process: For a small project with a capacity of 1000 m³/h, the initial investment is relatively low, approximately 500,000 yuan.
Adsorption + Desorption Complete System: The total investment for medium-sized equipment is relatively high. For example, a project with a capacity of 6000 m³/h would require approximately 1.2 million yuan.
Regenerative thermal oxidation system: The investment is the highest, usually ranging from 1.5 million to 3 million yuan per unit.
Economic benefits: The resource gains from toluene recovery can significantly offset and even completely cover the operating costs of environmental protection equipment.
Direct savings: Based on an annual operation of 300 days, a highly efficient toluene recovery system can achieve an annual recovery benefit of over 1.5 million yuan.
Investment return period: In industries where the value of organic solvents is relatively high (such as printing, dyeing and coating), the equipment investment can usually be recovered within 1-2 years.
