Study On Thermal Safety Of Toluene Adsorption By Activated Carbon

The calorific value of activated carbon is high,and in the process of adsorbing flammable volatile organic gases（VOCs）,heat is accumulated by the action of hot air flow,which is prone to accidents such as combustion of adsorption devices,and there are potential safety hazards in the process of activated carbon adsorption treatment of VOCs.Therefore,this paper studies the thermal safety of gas-solid hybrid system in the process of activated carbon adsorption of toluene,analyzes the explosion mechanism of toluene gas,activated carbon solid and gas-solid multiphase hybrid system,uses self-made temperature-sensitive materials to monitor the temperature and heat changes of different adsorption sites in the process of activated carbon adsorption of toluene,and reduces the thermal safety risk of the process of activated carbon adsorption of toluene by modifying coconut shell activated carbon by ionic liquid.The results of the study showed that:1)The pyrazole/L-proline carbon quantum dots（CDs）fluorescence effect was better at 11 h and 200°C in hydrothermal reaction,and the particles were approximately spherical particles with an average particle size of 4.45 nm.The color of temperature-sensitive materials responds to changes in temperature,and new absorption peaks are generated while retaining the characteristic absorption peaks of CDs.The temperature-sensitive material has a stable stage with obvious mass loss at 120.5～253.9°C.2)The activation energy required for coconut shell activated carbon combustion was E=35.78 k J·mol^-1,when the temperature was 45°C,the maximum thermal power of activated carbon was 584.3 m W,and 1000 g of coconut shell activated carbon adsorbed and exothermic 937.58 k J at 60°C.The spontaneous ignition temperature of coconut shell activated carbon with a median diameter of 51μm was 319.3°C,the lower explosion limit of activated carbon powder was 1.5～2.5 g·m^-3,and the maximum explosion pressure was0.57 MPa.3)After the modification of quaternary ammonium salt ionic liquid,the number of pores of activated carbon increased and the pore size became larger,and the adsorption capacity of paratoluene increased by 3 times.The spontaneous ignition point of modified activated carbon was increased by 19.4°C compared with that before modification,and compared with the original activated carbon adsorption of toluene,the lower explosion limit concentration of the system after adsorption of toluene by modified activated carbon increased,and the maximum burst pressure decreased from 0.57 MPa to 0.53 MPa.The activation energy required for combustion of activated carbon after modification was increased by 21.33 k J·mol^-1 compared with that before modification.At an adsorption temperature of 60°C,the heat release during the adsorption of toluene by 1000 g of modified activated carbon was 854.25 k J,which was 83.33 k J less than that of the original activated carbon.