The removal of volatile organic compounds by dry sorbent injection technique from gas streams

In this study, the adsorption of volatile organic compounds (chloroform and carbon tetrachloride) on porous solids (activated carbon and clinoptilolite) was investigated by the use of a fixed bed and dry sorbent injection (DSI) technique. Furthermore, DSI model equations were solved and compared with the experimental results.The fixed bed experiments were carried out at atmospheric pressure, the temperature of 40 °C, 3 L/min. gas flow rate and varying initial gas phase concentrations (130-1250 ppmv). Two different DSI experiments were conducted: 1. particle residence time experiments (at 1 atm, the temperature of 40 °C; at different gas flow rates, 3-5 L/min., initial gas phase concentrations, 500-2000 ppmv, and solid feeding rates, 0.0025-0.009 g/s) and 2. the dry sorbent injection system?s filter out experiments (at the same of experimental conditions at the particle residence time experiments, but for temperatures ranging from 30 °C to 50 °C).The experimental adsorption equilibrium knowledge of volatile organic compounds studied in activated carbon and clinoptilolite was proved by the use of breakthrough curves obtained from the fixed bed experimental results. The Freundlich and the Langmuir isotherm parameters were calculated by using the experimental adsorption equilibrium data. As a result, it was observed that the experimental adsorption equilibrium data of chloroform and carbon tetrachloride on activated carbon and clinoptilolite samples studied was also in agreement with the both isotherms.The particle residence time experimental results show that the adsorbed percent values of chloroform and carbon tetrachloride on activated carbon and clinoptilolite studied increase with both the increasing particle residence time and the increasing solid feeding rate. In contrast to, it is observed that the adsorbed percent values of chloroform and carbon tetrachloride on activated carbon and clinoptilolite studied decrease with the increasing initial bulk gas phase concentration and the increasing gas flow rate.In DSI filter out experiments, it was observed that the concentration of gas phase at the filter out decreased with time. This situation showed that the adsorption process in the filter was still undertaken. The decrease of gas phase concentration at the filter out was dramatically occurred with the increasing solid feeding rate. The adsorbed percent values of chloroform and carbon tetrachloride on the both solids in the filter decreased with the increasing initial bulk gas concentration. The concentration of gas phase at the filter out also decreased with the increasing of the gas flow rate. The filter out experiment results showed that the adsorbed percent values were decreased with the increasing temperature.It is observed that the adsorption of chloroform on activated carbon and clinoptilolite was more than that carbon tetrachloride for all experimental results carried out in the fixed bed and DSI system. However, adsorption on activated carbon of volatile organic compounds studied was more than that clinoptilolite.The results of DSI model equations solution were generally in agreement with the experimental results for the adsorption on activated carbon of chloroform and carbon tetrachloride. Because of the geometric standard deviation value, the DSI model solution for the adsorption on clinoptilolite of the both volatile organic compounds was weakly in agreement with experimental data.