Enabling continuous capture and catalytic conversion of flue gas CO 2 to syngas in one process

Abstract

Albeit a variety of available strategies for CO 2 conversion to useful chemicals and fuels, most technologies require relatively pure CO 2 , especially without oxygen and water.This requires additional steps of CO 2 capture and purification before its efficient conversion. This necessity increases energy requirement, leading to poorer carbon footprints and higher capital expenditures lowering the viability of overall CO 2 conversion processes. We have developed an effective technology which combines CO 2 capture and conversion processes using isothermal unsteady-state operation and a catalyst consisting of earth-abundant chemical elements (FeCrCu/K/MgO-Al 2 O 3 ).Diluted CO 2 streams common in process flue gases, even containing oxygen and water, can be fed to the process and relatively pure product stream such as syngas, i.e. carbon oxides (CO and CO 2 ) and hydrogen mixture, can be produced. A possible scheme of reactor integration for continuous CO 2 abatement and conversion based on a tworeactors system is presented.

Continuous CO2 capture and reduction in one process: CO2 methanation over unpromoted and promoted Ni/ZrO2

“…In this study, sufficiently long CO2 capture and reduction periods were used to compare the performance of the catalyst materials investigated. In practice, by shortening the periods, one can optimize a CCR process by maximally avoiding release of uncaptured CO2 and waste of H2, respectively [8]. It is worth noting that matching the duration of CO2 capture and reduction periods is important for process intensification using a two-reactor system [8].…”

“…During the capture phase, CO2 is chemically stored over catalyst, and before/upon reaching the maximum CO2 capture capacity of the catalyst, the gas atmosphere is switched to reduction phase, such as hydrogen atmosphere to convert the stored CO2 into a targeted product. In our first studies, a catalyst containing Cu as the main active reduction sites and K as CO2 capture sites was developed and CCR was demonstrated with >99% CO2 capture efficiency with diluted CO2 effluent streams even in the presence of oxygen and water and with high conversion efficiency to CO (in practice to syngas due to the presence of unconverted hydrogen) via reverse water-gas shift reaction (RWGS) [8,9].…”

“…Among active metal components for CO2 methanation, nickel was chosen for its widely recognized methanation activity and its high natural abundance, whereas ZrO2 was chosen as the support material for its good synergetic function in the reaction when used in conjunction with Ni [15,16]. Besides K which was found effective in promoting CO2 capture in our previous study [8,9], the use of La was investigated for its distinct property to capture CO2 under CCR conditions. Furthermore, the effects of each material components on the formation of active surface species and the reaction mechanism were studied in depth by operando space-and timeresolved diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS).…”

2D‐Layered Ni–MgO–Al2O3 Nanosheets for Integrated Capture and Methanation of CO2

“…Bobadilla et al. reported a two‐step unsteady C 4 process for capturing CO 2 from diluted sources and its reduction to CO with H 2 . Recently, a thermodynamically downhill “amine swing” process was demonstrated, where CO 2 could be rapidly absorbed by amines and then converted to calcium carbonate in high efficiency …”

Improving Fe/Al2O3 Catalysts for the Reverse Water-Gas Shift Reaction: On the Effect of Cs as Activity/Selectivity Promoter

“…Among the alkaline metals, potassium has been the most extensively studied as a catalytic promoter, often in conjunction with iron [25,26]. Caesium, on the other hand, has been subject to far fewer studies in the field.…”