Influence of Carbon Particle Characteristics on Oxidative Filtration Under Biomass Gasification Gas Atmosphere

The oxidation of filter cake particles (FCPs) is beneficial for preventing filter media blockage during the hot filtration of raw biomass gasification gas. The influence of particle characteristics on hot oxidative filtration was investigated through characterization, kinetic study, and lab-scale experiments. The characterization results indicated that FCPs are particles with C content of more than 60%, containing –CHn and C=O functional groups. After pyrolysis treatment, these functional groups gradually diminished, while the degree of atomic nucleus condensation increased. The oxidation kinetic calculation indicated that the oxidation activation energy of particles ranged from 55.24 to 117.84 kJ/mol, and higher treatment temperatures could reduce the particle reactivity. The hot oxidative filtration at 400 °C revealed that the primary reaction was C + O2 = CO2 rather than combustion or oxidation of combustive gas components. Furthermore, it was observed that the active minerals on the surface of carbon particles would promote the catalytic oxidation of CO. Experimental findings confirmed that the untreated FCPs containing abundant –CHn functional groups could effectively react with low-concentration O2. However, the presence of active minerals on the particle surface likely promoted CO oxidation within the FCP layer, thereby reducing the calorific value of the product gas.