In the treatment of synthetic and distillation tail gases from silicone production, our company employs a combined process of thermal incineration, waste heat recovery, high-temperature dedusting, and flue gas absorption and neutralization, integrating our proprietary technology. The heat generated from incineration is recovered by a waste heat boiler to produce 1.1 MPa steam for factory use. After high-temperature dedusting, the flue gas containing hydrogen chloride is subjected to rapid cooling and absorption treatment, recovering 30% hydrochloric acid. It is then neutralized with alkali wash before being discharged in compliance with the standard GB18484-2001 "Pollution Control Standard for Incineration of Hazardous Waste."
Process Features:
1. The synthetic and distillation off-gases emitted during silicone production have high calorific values, and their combustion can fully meet the requirements for off-gas incineration, with theoretical incineration temperatures reaching about 1400°C. Effective measures must be taken to prevent temperature surges during the incineration process. This process employs the method of injecting 10% waste hydrochloric acid into the furnace to lower the combustion temperature, reduce the amount of excess oxygen in the flue gas, inhibit the formation of Cl2, and create conditions for recovering 30% of the hydrochloric acid. The amount of 10% waste hydrochloric acid injected is automatically adjusted to control the furnace temperature.
2. This technology employs a micro-negative pressure operating system for incineration, keeping the entire system under negative pressure. There is no leakage of waste gas or hydrogen chloride-containing flue gas, ensuring both safety and preventing secondary pollution.
3. After flaring organic silicon off-gases, the flue gas contains HCL gas and produces a large amount of SiO2 dust. The use of a vertical waste heat boiler, along with the installation of an ultrasonic descaling device on the boiler, effectively resolves the issue of dust blockage in the waste heat boiler. The design pressure of the waste heat boiler is 1.1 MPa, with a corresponding saturation temperature of R180℃. This can effectively increase the wall temperature of the heat exchange tubes. The exhaust gas temperature is controlled around 250℃, significantly higher than the dew point temperature of HCL in the flue gas, thereby effectively preventing dew point corrosion in the waste heat boiler.
4. Post-exhaust gas boiler, a high-temperature bag dust collector is used to prevent dust from entering the subsequent absorption system, effectively ensuring the quality of the recovered hydrochloric acid.
5. The absorption of HCL in flue gas employs an emergency cooling condensation absorption tower and a secondary acid washing tower to enhance the absorption efficiency of hydrochloric acid, absorbing over 90% of the HCL gas from the flue gas and recovering 30% of the hydrochloric acid.
6. Added a demister before the alkali washing tower to capture the hydrochloric acid droplets carried by the flue gas, reducing the consumption of alkali solution in the alkali washing tower and ensuring that the HCL gas in the emitted flue gas meets the emission standards.
