利用碳捕集、封存系统（CCS）减排燃煤电厂CO2是碳中和必经之路，但目前较高的碳捕集、封存成本限制了该技术的发展和应用。针对某300 MW燃煤机组，利用Aspen Plus模拟软件提出并搭建了基于碱金属基干法碳捕集、封存耦合供冷系统，利用凝结水循环进行深度耦合，达到回收CO2压缩封存过程中冷量的目的，有效降低碳捕集成本。在不耦合供冷过程的情况下，通过回收CO2吸附过程释放的反应热，降低碳捕集系统单位耗电量至413.79 kWh/t（以CO2计，下同）；此时CO2压缩封存过程能耗仍巨大。为此，在上述碳捕集封存系统进一步耦合供冷机组。通过模拟计算可得集成后新系统降低了CO2压缩程度，此时加压封存过程的单位耗电量降至247.54 kWh/t，降低了2.3%，CO2捕集封存总运行成本进一步降低33.77%。此外，供冷机组的引入还会降低额外投资成本，如通过提高CO2吸附床内的换热温差，减少受热面布置量和吸附剂装载量，从而减少吸附床尺寸，优化效果明显。上述工作为CO2捕集、封存技术推广和应用提供支撑，拓宽了CO2的利用途径。

The use of carbon capture and storage (CCS) system to reduce CO2 in coal-fired power plants is one of the necessary paths to carbon neutrality, but the current high cost of CCS has limited the development and application of this technology. For a 300 MW coal-fired unit, an alkali metal-based dry carbon capture and storage coupled cooling system was proposed and built using Aspen Plus simulation software, which used condensate circulation for deep coupling to achieve the purpose of recovering the cold volume in the CO2 compression and storage process and effectively reduce the carbon capture cost. Without coupling the cooling process, the unit power consumption of the carbon capture system is reduced to 413.79 kWh/t (in terms of CO2, the same below) by recovering the reaction heat released from the CO2 adsorption process. The energy consumption of the CO2 compression and storage process is still significant at this point. For this reason, the carbon capture and storage system described above was further coupled to a refrigeration unit. The simulation calculation shows that the new integrated system reduces the degree of CO2 compression and the unit power consumption of the compression storage process is reduced to 247.54 kWh/t, a reduction of 2.3%, resulting in a further 33.77% reduction in the total operating cost of CO2 capture and storage. In addition, the introduction of cooling units can reduce additional investment cost reductions, such as reducing the amount of heated surface arrangement and adsorbent loading by increasing the heat transfer temperature difference within the CO2 adsorption bed, and thus reducing the adsorption bed size with obvious optimization effects. Therefore, the above work provides an important support for the promotion and application of CO2 capture and storage technology, and also broadens the way of CO2 utilization.

0 引言

1 模型与方法

   1.1 模型介绍

   1.2 性能分析方法

2 模型建立与验证

   2.1 汽水系统模型

   2.2 碳捕集系统模型

   2.3 压缩制冷系统模型

   2.4 碳捕集、封存耦合供冷系统模型

3 经济性评价

4 结论