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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.

Crystallisation fouling is a challenge in numerous applications. To mitigate fouling we need to determine the basic mechanisms involved in the process. While ex situ techniques have been widely used in previous studies, they cannot capture complex dynamic effects. We conducted an in situ investigation of the dynamic effects of crystallisation fouling in a steel pipe (length 3 cm, diameter 3 mm) using X-ray micro-computed tomography (µCT) over more than six days. We employed a custom-developed image reconstruction algorithm, which ensured high spatiotemporal resolution from a laboratory instrument. We quantified the evolving fouling using advanced segmentation techniques of 4D images. To understand how the pipe interface structure impacts reactive transport, the experimental geometries of the flow system were used to perform computational fluid dynamic simulations. These new data allowed us to identify three growth phases: initiation, expansion, and densification

Crystallization fouling in heat exchangers, subsurface energy production, and membrane technology remains a challenge. The reactive crystallization process is governed by whether growth or nucleation dominates the precipitation process. However, there is little direct experimental evidence on the fundamentals of nucleation and growth on surfaces over a wide range of supersaturations. We investigated the crystallization fouling of BaSO4 at 10 different supersaturations (saturation ratios from 6.6 to 457.1). We show that deposition behavior changes from a growth-dominated regime to a nucleation-dominated regime as the supersaturation increases; these changes in the dominant regime affect the resilience of the surface deposits. At low supersaturations, crystals have a secondary order, which increases their surface resilience. At high supersaturations, where nucleation processes dominate, crystals aggregate on the surface with no discernible secondary structure. At a saturation ratio of 457, nucleation processes are accelerated, causing previously aggregated crystals to become isolated. Due to increased isolation, the crystal resilience decreases, and the crystals become more vulnerable to detaching from the surface. To characterize surface deposition, we introduced the sticking factor as a measure of the stickability. We present an analysis of the stickability of BaSO4, CaCO3, and CaSO4, based on published data, and observe mean sticking factors of 1.15%, 0.80%, and 0.11%, respectively.

Fouling processes present significant challenges in many industries; understanding these processes is crucial for accurate prediction and planning effective mitigation protocols. Composite fouling is prevalent in many industrial applications, however, studies of these systems are scarce. In this work, we investigate crystallization fouling in composite systems to understand how substrate properties affect foulant growth behaviour. Crystal (BaSO4 and CaCO3) deposition studies were performed in a once-through flow setup. We used high-resolution X-ray micro-computed tomography scanning to visualize the formed crystals. We extracted the distribution of the shapes, frequencies of the protuberances, surface coverage and density of clusters through image analysis. Our results reveal that deposition behaviour depends on complex substrate-foulant interactions. Whereas the net deposition of CaCO3 on a BaSO4 substrate increased with time, significant detachment processes were observed for the reverse case. The increased detachment of BaSO44on a CaCO3 substrate can be attributed to either the weak interaction within the CaCO3 crystal structure or the CaCO3/steel interface. We also observe that substrate properties govern crystal cluster sizes and distribution. The results from this work provide a basis for the development of more accurate prediction models.

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