Arias Borja, Criado Yolanda A, Abanades J Carlos
CSIC-INCAR, C/Francisco Pintado Fe, 26, 33011 Oviedo, Spain.
ACS Omega. 2020 Mar 3;5(10):4844-4852. doi: 10.1021/acsomega.9b03552. eCollection 2020 Mar 17.
The CO capture from back-up power plants by making use of calcium looping systems combined with large piles of Ca-solids has been studied in this work. A flexible CO capture system based on a concept described in a previous work has been integrated into an existing power plant by including a small oxy-fired calciner (that represents just 8% of the total thermal capacity) to steadily regenerate the sorbent and a carbonator reactor following the back-up power plant operation periods to capture 90% of the CO as CaCO and two large piles of rich CaO and CaCO solids stored at modest temperatures. When the back-up plant enters into operation, the calcined solids are brought into contact with the flue gases in the carbonator reactor; meanwhile, the oxy-calciner operates continuously at a steady state. In order to improve the flexibility of the CO capture system and to minimize the increase of CO capture costs associated with the additional new equipment used only during the brief back-up periods, we propose using the steam cycle of the existing power plant to recover a large fraction of the heat available from the streams leaving the carbonator. This makes it possible to maintain the electrical power output but reducing the thermal input to the power plant by 12% and thus the size of the associated CO capture equipment. To generate the auxiliary power required for the oxy-calciner block, a small steam cycle is designed by integrating the waste heat from the streams leaving this reactor. By solving the mass and heat balances and proposing a feasible thermal integration scheme by using Aspen Hysys, it has been calculated that the CO emitted by long-amortized power plants operated as back-up can be captured with a net efficiency of 28%.
在本研究中，利用钙循环系统结合大量钙固体从备用发电厂捕获二氧化碳。基于先前工作中描述的概念，一个灵活的二氧化碳捕获系统已被集成到现有的发电厂中，该系统包括一个小型氧燃烧煅烧炉（仅占总热容量的8%），用于稳定地再生吸附剂，以及一个碳酸化反应器，在备用发电厂运行期间之后捕获90%的二氧化碳生成碳酸钙，并在适度温度下储存两堆大量的富氧化钙和碳酸钙固体。当备用发电厂投入运行时，煅烧后的固体在碳酸化反应器中与烟道气接触；同时，氧煅烧炉在稳定状态下持续运行。为了提高二氧化碳捕获系统的灵活性，并尽量减少仅在短暂备用期间使用的额外新设备所带来的二氧化碳捕获成本的增加，我们建议利用现有发电厂的蒸汽循环来回收离开碳酸化器的物流中可用的大部分热量。这使得在维持电力输出的同时，将发电厂的热输入降低12%，从而减小相关二氧化碳捕获设备的尺寸。为了产生氧煅烧炉模块所需的辅助电力，通过整合离开该反应器的物流中的废热设计了一个小型蒸汽循环。通过求解质量和热量平衡，并使用Aspen Hysys提出可行的热集成方案，计算得出作为备用运行的长期摊销发电厂排放的二氧化碳可以以28%的净效率被捕获。
