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Post-combustion carbon capture is a well-established technology for removing CO from industrial emissions. However, research is still underway to optimise the process and make it more energy efficient. The current work aims to present the results from pilot-scale (with a capacity of 1 tonne CO/day) studies of CO capture conducted at Amager Bakke, a Waste-to-Energy facility in Copenhagen, Denmark. The pilot operation is fully automated, and the process control structure helps achieve multiple steady states at regular intervals. In addition, the pilot is capable of several configurations which can assist in optimising the energy required for solvent regeneration. The current work discusses the base case configuration of the pilot plant by employing 30 wt MEA as the solvent. Experiments were conducted to analyse the influence of reboiler duty, solvent flow rate, and gas flow rate on the pilot’s performance. The influence of these parameters on several aspects is discussed in detail, and recommendations for the optimal operation of such plants are provided. An optimum specific reboiler duty of 3.46 GJ/tonne CO is obtained at a solvent flow rate of 306 kg/h, flue gas flow rate of 113 kg/h, and reboiler duty of 17.5 kW excluding heat loss.

Post-combustion carbon capture is a well-established technology to limit CO2 from industrial emissions. However, challenges such as high energy requirements for solvent regeneration persist. Research is still being conducted to improve the energy efficiency of the process. This study aims to present the results of process intensification in a pilot-scale CO2 capture plant. The pilot-scale investigations were carried out at Amager Bakke, a Waste-to-Energy facility in Copenhagen, Denmark. The tests were conducted by implementing the split flow configuration as a method of process intensification. The CO2 rich stream was split before flowing through the rich/lean heat exchanger. One of the split streams was fed to the stripper top, and the other was sent through the heat exchanger and then fed to the stripper. The cold split stream at the stripper top is heated by the overhead vapours which would otherwise escape the stripper. The current work discusses the split flow configuration results of the pilot plant by employing 30 wt MEA as the solvent and compares it to the base-case performance of the pilot. Experiments were conducted by splitting 22% of the rich solvent and feeding it to the stripper top. The performance of the split flow configuration was analysed at different reboiler duties. A minimum specific reboiler duty of 3.45 GJ/tonne CO2 is obtained for the split flow configuration, which is less than the base case by 7.8%. Additionally, a reduction in the condenser duty by at least 68% was achieved by the implementation of the split flow configuration.

Monoethanolamine (MEA) is the most used solvent compared to other amines for CO2 capture in the post-combustion processes [1]. However, disadvantages like the requirement of high energy for desorption [4], reduction in CO2 carrying capacity of the solvent [2], and thermal degradation of MEA at the stripper operating conditions [3] are major causes of concern for large scale post-combustion CO2 capture plants.These drawbacks can be countered by intensifying the capture process. Use of ultrasound to assist the stripping of the solvents by heat can significantly unlock cost savings in CO2 capture plants [5]. Ultrasound results in cavitation in liquids leading to the formation of bubbles which grow by further diffusion of gas into them, thus providing an easier way for the gas to escape in the form of bubbles [6].The aim was to determine the rate and amount of CO2 desorbed from loaded MEA solventsand the impact of various parameters like the concentration of MEA, intensity of ultrasonic power, temperature, and loading of the solvent. In addition, innovative additives developed at DTU known as the Vapor Reduction Additives (VRAs) have also been tested at different concentrations. VRAs have the capacity to reduce the vapour pressure of water and similar solvents including amines, which reduces the amount of water evaporated and thus the energy required in the condenser and reboiler sections. Use of ultrasound in addition to the VRAs can significantly reduce the size of the equipment in addition to the reduction in operational costs.