Environment-friendly and energy-saving thermal-desorption remediation treatment system for organic contaminated soil

Abstract

The invention relates to an environment-friendly and energy-saving thermal-desorption remediation treatment system for organic contaminated soil and aims to provide the energy-saving, environment-friendly and efficient thermal-desorption remediation treatment system for organic contaminated soil. The system comprises a feeding system, a thermaldesorption system, a soil discharging system, a combustion and tail gas treatment system, a flue gas temperature control system, a tail gas temperature-reduction and dust-removal system and a tail gas exhaust system, wherein the feeding system is led to the thermaldesorption system, the thermaldesorption system is led to the soil discharging system and the combustion and tail gas treatment system respectively, the combustion and tail gas treatment system is led to the flue gas temperature control system, the flue gas temperature control system is led to the thermal desorption system, the thermaldesorption system is led to the tail gas temperature-reduction and dust-removal system, and the tail gas temperature-reduction and dust-removal system is led to the tail gas exhaust system.

Description

technical field [0001] The invention relates to the field of soil restoration, in particular to a thermal desorption restoration treatment system for organic polluted soil. Background technique [0002] Thermal desorption technology is one of the effective technologies for remediation of volatile / semi-volatile organic contaminated soil, and has been successfully applied to polycyclic aromatic hydrocarbons, non-chlorinated volatile and semi-volatile organic pollutants, benzene series, organic pesticides, Remediation of soil contaminated by herbicides. The earliest thermal desorption remediation process in China is a treatment process and device for soil contaminated by volatile and semi-volatile organic compounds (ZL200410056888.7). This process uses low-temperature direct heating to heat up the soil relatively quickly, but the system cannot Continuous feeding, low processing efficiency; Tsinghua University invented a drum-type reverse direct heating thermal desorption equip...

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Problems solved by technology

Both the activated carbon adsorption method and the organic solvent method need to cool down the high-temperature gas before treatment. Generally, a washing cooling tower or a condenser is used to cool down. Due to the large amount of tail gas and high temperature in the thermal desorption process, the cooling cost is high and the efficiency is low. The activated carbon with saturated adsorption belongs to Hazardous waste needs to be transported to institutions with relevant treatment qualifications for unified treatment. The transportation and treatment procedures are complicated and costly

The UV photocatalysis / O3 oxidation method mainly uses ultraviolet light radiation to destroy pollutants, but the energy of ultraviolet light is low, so it can only deal with simple and easily oxidized organic gases, such as methyl mercaptan

Low-temperature plasma has high energy and can destroy most of the molecules of organic gases. However, this technology is mainly used to treat gases at room temperature. For high-temperature rotary kiln exhaust gas, it needs to be greatly cooled, and the one-time investment in equipment is relatively large.

The combustion method in the second combustion chamber can completely decompose harmful substances. When the exhaust gas is at a furnace temperature ≥ 1000°C and the residence time is ≥ 2.0s, the removal rate of organic pollutants can reach 99.999%. However, the combustion method in the second combustion chamber consumes a lot of energy. According to general Based on the experience of contaminated soil treatment, the energy consumed by the secondary combustion chamber in the traditional thermal desorption system is about 1.5 times the energy consumed by the rotary kiln heating

Although the treatment efficiency of the second combustion chamber combustion method is high, the huge energy consumption limits the application of this method, and it is generally used for tail gas treatment with high organic gas content

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