A compact CO2 capture process to combat industrial emissions

工业排放是大气二氧化碳的重要来源，英国必须解决这一问题，才能实现其具有法律约束力的目标。工业排放的二氧化碳通常来自一些小的、低浓度的来源，具有广泛的烟气成分和杂质分布。例如，在一家炼油厂，许多工艺炉、制氢装置和发电厂排放二氧化碳，排放点散布在几平方公里的范围内。如果采用集中式CCS工厂，将需要庞大的管网和压缩功率。此外，捕集器需要处理各种杂质。这并不是最佳选择。相反，更有效的捕获过程设计包括在现场不同位置的几个单独的定制捕获单元，仅共享一条共同的高浓度二氧化碳出口管道。因此，拥有几个紧凑和灵活的捕获设备是有益的，这些设备具有低运营和资本成本，能够利用来自不同工艺单元的废热的高效率。使用胺溶剂捕获二氧化碳是大多数碳捕获工厂采用的最成熟的技术，包括位于加拿大边界大坝的世界上第一个大型CCS工厂。这项技术被认为是下一代技术的参考。通过使用容量较高和/或再生/降解成本较低的替代胺或胺混合物进行逐步改进是有可能的。然而，这种传统工艺的主要问题仍然是没有根本不同的设计。这些问题包括：(A)吸收和解吸塔的传质效率低，导致设备尺寸大，资本和运营成本高；(B)溶剂再生能耗高，导致能源惩罚和运营成本非常高；(C)浓胺溶液造成腐蚀，这使得需要使用更昂贵的材料；(D)100 oC以上的胺的热和氧化降解。更多的溶剂组成意味着更高的操作成本我们建议通过结合旋转填充床吸收和微波辅助再生两种技术来应对这一挑战，这将使小型且灵活的捕获设备能够安装在广泛的工业现场。与传统的吸收塔相比，旋转填充床柱的体积大大减少了90%，而微波再生是一种革命性的方法，可以在70oC(而不是120oC)下再生胺溶液，该方法可以在不发生温度波动的情况下运行，并且非常快速，从而进一步显著降低了资本成本(约50%)，用于二氧化碳解吸的显热，以及腐蚀和溶剂降解超过90%。二氧化碳在70摄氏度下的解吸也使再生器能够使用低品位的工业废热。

Industrial emissions are an important source of atmospheric CO2 that must be tackled for the UK to meet its legally binding targets. CO2 emissions from industry occur typically from a number of small, low concentration sources with a wide range of flue gas compositions and impurity profiles. For example, in a refinery, CO2 is emitted from many process furnaces, hydrogen production units and power generation plant, and emission points are scattered over several km2. If a centralized CCS plant is applied, a large piping network and compression power will be required. Moreover, the capture unit would need to deal with a wide range of impurities. This is not optimal. Instead, a much more efficient capture process design involves several separate and bespoke capture units at different locations on site, sharing only a common high concentration CO2 export pipeline. It is therefore beneficial to have several compact and flexible capture units, with low operating and capital costs and high efficiency able to use waste heat from different process units.CO2 capture by using amine solvents is the most mature technology employed in most carbon capture plants, including the world's first large-scale CCS plant at Boundary Dam, Canada. This technology is considered a reference for next-generation technologies. Incremental improvements through the use of alternative amines or amine mixtures with higher capacity and/or lower regeneration/degradation costs are potentially possible. However, major problems with this conventional process remain without a fundamentally different design. They include (a) low mass transfer efficiency in the absorber and desorber, resulting in large equipment size and high capital and operating costs, (b) high energy consumption in solvent regeneration, causing a very high energy penalty and operating cost, (c) corrosion caused by concentrated amine solutions, which makes it necessary to use more expensive materials, (d) thermal and oxidative degradation of amines above 100oC. More solvent make-up means high operating costWe propose to meet this challenge by combining two technologies, rotating packed bed absorption and microwave-assisted regeneration, which will enable small and flexible capture devices to be installed at a wide range of industrial sites. A rotating packed bed column offers a dramatically reduced volume by 90% compared to a traditional absorption column, while microwave regeneration is a revolutionary method for regenerating amine solutions at 70oC (rather than 120oC) that can operate without a temperature swing and is very fast, leading to further significant reduction in capital costs (by around 50%), in the sensible heat used for CO2 desorption, and in corrosion and solvent degradation by over 90%. CO2 desorption at 70oC also enables the regenerator to use low grade industrial waste heat.