Process intensification technologies for CO2 capture and conversion – a review

Abstract

With the concentration of CO 2 in the atmosphere increasing beyond sustainable limits, much research is currently focused on developing solutions to mitigate this problem. Possible strategies involve sequestering the emitted CO 2 for long-term storage deep underground, and conversion of CO 2 into value-added products. Conventional processes for each of these solutions often have high-capital costs associated and kinetic limitations in different process steps. Additionally, CO 2 is thermodynamically a very stable molecule and difficult to activate. Despite such challenges, a number of methods for CO 2 capture and conversion have been investigated including absorption, photocatalysis, electrochemical and thermochemical methods. Conventional technologies employed in these processes often suffer from low selectivity and conversion, and lack energy efficiency. Therefore, suitable process intensification techniques based on equipment, material and process development strategies can play a key role at enabling the deployment of these processes. In this review paper, the cutting-edge intensification technologies being applied in CO 2 capture and conversion are reported and discussed, with the main focus on the chemical conversion methods.

Electrochemical carbon dioxide capture to close the carbon cycle

“…In addition to fuels, chemicals such as ethylene, alcohols, formic acid (or formate), syngas, urea and other organic materials can be produced from CO 2 , electrochemically, thermo-chemically or by other approaches [323,[329][330][331][332][333][334][335][336][337]. Such organic chemicals are often more expensive than fuels and may offer advantages in the techno-economic analysis.…”

Emerging applications of process intensification for enhanced separation and energy efficiency, environmentally friendly sustainable adsorptive separations: A review

“…Much better intensification levels can be obtained by the combination of materials, methods and equipment, or two or more technologies in a given process. 42,43 Many kinds of adsorbents are utilised in adsorptive separations, such as activated carbon, zeolites and carbon molecular sieves. However, they might be associated with low adsorption capacities towards an adsorbate especially at large-scale processing.…”

“…So, many efforts have been devoted to means to further improve the performance of various adsorbents. 43 In this study, emerging applications of PI on adsorptive separations as an innovative approach in recent years were considered, and the selected trends were identified with comparison in terms of the applied adsorption technology, intensification technique and the achieved process enhancements. Selected PI studies from the literature for different cases of adsorption separations are shown in Table 2.…”

“…Much better intensification levels can be obtained by the combination of materials, methods and equipment, or two or more technologies in a given process. 42,43 There is a growing research trend on means to further develop the performance of various adsorbents. 43 The PI techniques applied to adsorption separation mainly involved the use of modified adsorption systems, extended mass transfer, setting higher overall driving force, process integration, thermal integration, novel adsorbents, hollow-fibre bed, microreactor, acoustic cavitation/ultrasonication or heat pump coupled with adsorption, low-temperature processes and microwave reactor.…”

Operability and control in process intensification and modular design: Challenges and opportunities

“…In Table 1, we provide a summary of the latest review/perspective papers to highlight the major scientific and industrial interests in this field since 2018. As can be noted, a diversity of intensified and modular technologies are being investigated to address the dual challenge of energy productivity/efficiency and environmental sustainability, 30 for example, reactive distillation, 24 intensified reactors, 15 alternative energy sources, 14 and advanced materials 33 . Another rapidly emerging research theme is computer‐aided process intensification 11,32 .…”