|
Biogas, which is a new renewable energy, has been purified and used comprehensively as the automobile compressed natural gas (CNG) in the world, thus reduce the discharge of PM2.5in comparison with using typical fossil fuel. Biogas purification process including deoxidation(02), desulphurization(H2S), decarburization(CO2), and etc. Due to the lower concentration of O2and H2S in the biogas, using traditional catalytic deoxygenation and chemical absorption desulfurization methods would result in larger energy consumption and high cost, what’s more, deoxidation and desulphurization processes were typically carried out individual. To this end, a new method using dielectric barrier discharge (DBD) plasma was put forward to simultaneous removing the O2and H2S in oxygenated simulated biogas, the main content as well as the achieved conclusions are as follows:(1) The biogas deoxidation experiments were conducted in the DBD plasma reactor without H2S in the simulated biogas. Effects of energy density, initial volume concentration of O2, with and without CO2on the removal efficiency of O2, selectivity of gaseous product and selectivity of liquid product were investigated, respectively. Results showed that biogas deoxidation products were mainly inflammable gas and liquid. Increasing energy density was beneficial to deoxidation process and the production of liquid products. Higher concentration of O2was beneficial to the generation of liquid products. When energy density was more than21kJ/L, CO2concentration has the slightly effect on the removal of O2.(2) The biogas desulphurization experiments were conducted in DBD plasma reactor with O2in the simulated biogas. Effects of energy density, initial volume concentration of H2S, residence time and initial volume concentration of O2on the removal efficiency of H2S were investigated, respectively. Results showed that H2S in simulated biogas with O2in the simulated biogas could be removed completely under higher energy density in the DBD plasma reactor, and the mainly oxidation products of H2S were sulfur dioxide and a few of solid sulfur. The removal efficiency of H2S increases with the increase of energy density, residence time and initial volume concentration of O2, decreases with the increase of initial volume concentration of H2S. When energy density was up to24.1kJ/L, H2S could be removed completely, meantime, the volume concentration of O2in simulated biogas was also decreased below0.5%, which reached the national standard of CNG, as a result, O2and H2S in oxygenated simulated biogas could be simultaneous removed.(3) A dynamic model was developed for the removal of H2S in oxygenated simulated biogas using DBD plasma technology. Effect of initial volume concentration of H2S on the reaction rate coefficient based on the dynamic model was investigated. Results showed that the reaction rate coefficient increased with the increase of the initial volume concentration of H2S, which is consistent with the experimental results.
|