响应面曲线法优化含盐污水协同电石渣矿化封存CO2

针对电石渣湿法矿化消耗水资源较多的问题，采用实际化工含盐污水作为反应介质，开展电石渣湿法矿化封存CO₂实验。探究温度、压力、液固比等单因素对电石渣矿化固碳封存率的影响，并采取Box-Behnken响应面曲线法对工艺条件进行优化。结果表明，污水和去离子水为介质的电石渣矿化封存CO₂封存率分别为59.59%和59.89%。温度和液固比对CO₂封存率的影响较大，压力影响较小，且在温度65 ℃、压力1.0 MPa和液固比5 mL·g⁻¹的优化实验条件下的CO₂封存率分别达到47.56%、52.79%和63.47%。响应面曲线法实验结果表明，温度和液固比之间的交互作用最为显著，温度和压力、液固比和压力的交互作用不显著。同时确定，在反应温度85 ℃、初始反应压力0.5 MPa、液固比7.5 mL·g⁻¹的最优工艺条件下，含盐污水协同电石渣矿化的CO₂封存率为66.1%。本研究结果可为研发“气 (CO₂) - 液 (含盐污水) - 固 (电石渣) ”协同的二次资源循环利用技术提供参考。

Optimization of carbon dioxide sequestration by carbide slag mineralization with chemical salty wastewater by response surface methodology

In view of the problem that the wet mineralization of carbide slag consumes a lot of water resource, an experimental study on carbon dioxide sequestration by carbide slag wet mineralization was carried out using actual chemical salty wastewater as the reaction medium. The effect of temperature, pressure, liquid-solid ratio and other single factors on carbon sequestration rate of calcium carbide slag was studied, and then Box-Behnken response surface curve method was used to optimize the process conditions. The results showed that the CO2 sequestration rates of calcium carbide slag mineralization with wastewater and deionized water as media were 59.59% and 59.89%, respectively, basically unchanged. The experiment revealed that temperature and liquid-solid ratio had a great influence on CO2 sequestration rates, while pressure had a small influence. Under the optimized experimental conditions of temperature 65 ℃, pressure 1.0 MPa and liquid-solid ratio 5 mL·g−1, the CO2 sequestration rate reached 47.56%, 52.79% and 63.47%, respectively. The results of response surface curve method showed that the interaction between temperature and liquid-solid was the most significant, while temperature and pressure, liquid-solid and pressure were not significantly interacted. At the same time, under the optimal conditions of reaction temperature 85 ℃, initial reaction pressure 0.5 MPa and liquid-solid ratio 7.464 mL·g−1, the CO2 sequestration rate of salt wastewater coordinated calcium carbide slag mineralization reached 66.1%. This study can provide a reference for the further development of synergy technology of the secondary resource cycle of the industrial enterprise “three pollutants emissions”, for example CO2, salty wastewater and calcium carbide slag.