钙基吸附剂热解/碳酸化循环分离CO_2过程的研究

Study on CO_2 Sequestration Using Calcium-Based Sorbent during Cyclic Carbonation/Pyrolysis Process

钙基吸附剂热解/碳酸化循环再生CaO吸附CO2是燃煤电站控制CO2排放的有效方法之一。随着热解/碳酸化循环反应次数的增加,烧结使再生的CaO的碳酸化转化率迅速降低。为了使CaO在长期循环热解/碳酸化再生过程中保持较高的CO2吸附能力,分别采用3种溶液改性钙基吸附剂,包括乙醇水溶液、醋酸溶液和KMnO4溶液。同时对贝壳循环吸附CO2的特性进行了研究。研究表明,经乙醇和醋酸溶液改性后,热解产生的CaO的循环碳酸化转化率得到明显提高,抗烧结性能得到增强,并且比表面积和比孔容显著增大。经KMnO4溶液改性后的钙基吸附剂的循环转化率也得到了提高,这是由于KMnO4分解的活性物质催化了CaO的碳酸化反应。数据表明贝壳作为钙基CO2吸附剂是可行的。改性的钙基吸附剂和贝壳作为CO2吸附剂具有良好的应用前景。

The process of the regenerable CaO adsorbing CO2 during calcium-based sorbents pyrolysis/carbonation cycles is one of the efficient ways to capture CO2 from coal-fired power plants. CaO calcined from limestone exhibits a sharp decrease in carbonation conversion due to sintering as the number of carbonation/pyrolysis cycles increases. So it was proposed that calcium-based sorbents were modified with three kinds of solvents including ethanol water solution,acetic acid solution and KMnO4 water solution to improve CO2 adsorption capacity of CaO during long-term pyrolysis/carbonation cycles. The results show that the ethanol water solution and acetic acid solution modifications obviously increase cyclic carbonation conversion of CaO,and its anti-sintering performance is also enhanced,as well as the specific surface area and pore volume of CaO are significantly increased. The cyclic conversion of sorbent modified with KMnO4 solution is also improved because the active material decomposed from KMnO4 catalyses the carbonation reaction of CaO. The experimental data show that shells are proved to be fe-3sible as a CO2 sorbent. The modified calcium-based sorbent and shells are new and efficient CO2 sorbents for industrial applications.