Study On The Performance Of Recycling Carbon Dioxide By Modified Papermaking

The excessive CO2 emission is the primary reason for global warming. It is well accepted that CaO is a kind of sorbents most likely to be industrialized due to its affordability and high CO2 adsorption capacity. Operating at high temperatures is advantageous for heat recovery and reasonable use of the additional heat generated from CaCC3 decomposition. Therefore, using calcium-based sorbent under high temperatures to capture the CO2 of exhaust gas.China has occupied approximately 50 wt%of the global paper yield (over 50 million tons per year). Lime mud, a kind of toxic industrial waste, comes from the causticization reaction in alkali recovery process of paper-making industry. One ton of pulp produces about 0.5 ton of lime mud. Therefore, it is urgent to find out one way to reuse lime mud and decrease the burden of environment. Lime mud is composed of CaCO3. As for the performance of lime mud, this study is divided into four parts:Lime mud were directly doped with mineral rejects-bauxite-tailings (or aluminum nitrate nonahydrate) in this study. Effects of BTs content, precalcining temperature and time on CO2 cyclic absorption stability were illustrated to obtain the sorbent of best performance.The impurities of lime mud will affect the cyclic absorption and stability. Therefore, using sucrose method to purify lime mud. The single factor method was used to select the best extraction conditions of sucrose solution. In order to obtain the best performance sobent, the effects of precalcining temperature, precalcining time and mineral rejects-auxite-tailings content on CO2 cyclic absorption stability was study.According to the above study, GLM-BTs-10-4-800 has both good cyclic performance and economic benefits. The effect of different CO2 content on cyclic absorption property was studied.Because of the continuity of the industrial production, the practicability of the calcium-based sorbent after a longer series cycles was tested in this paper.Using common dynamics model (mechanism model, grain model) to subsection simulate the dynamics of GLM-BTs-10-4-800, the reaction mechanism of adsorption were based on simulation results.According to the study. LM-BTs-15-4-800 with being 25.4%conversion after 15 cycles, there was a 19.1%improvement of LM; LM-A1N-15-5-800 with being 43.5%conversion after 15 cycles, there was a 37.2%improvement of LM; GLM-BTs-10-4-800 with being 38.8%conversion after 15 cycles, there was a 32.5%improvement of LM.The conversion will increase suddenly with switching atmosphere, which will aggravate sorbent sintering. This phenomenon decreased when the CO2 concentration was low. GLM-BTs-10-4-800 exhibited good stability and low deactivation rate duiring 30 cycles (only decreased 14.3%). Finally, according to the carbonation simulation results, the adsorption kinetics of GLM-BTs-10-4-800 were divided into three part:pure chemical reaction, simultaneous chemical reaction and diffusion control stage and pure diffusion stage.