Energy-Saving Effect of Low-Cost and Environmentally Friendly Sepiolite as an Efficient Catalyst Carrier for CO₂ Capture

Abstract

Recently, the development of efficient solid acid catalysts to promote the CO 2 desorption rate while reducing energy consumption has attracted much attention. In this work, low-cost environmentally friendly sepiolite (SEP) clay was evaluated as a support of metal oxide (Fe 2 O 3 , CuO) catalysts. By comparing their catalytic performances for CO 2 desorption from CO 2 -rich monoethanolamine (MEA) solution at 100 °C, the obtained results showed that the tested catalysts can accelerate the CO 2 release rate and reduce heat consumption in comparison with the non-catalytic MEA solution. The relative heat duty found decreased in the following order: blank (100%) > SEP (66.4%) > CuO-SEP (58.8%) > Fe 2 O 3 -SEP (54.0%). Recycling tests to study stability demonstrated that Fe 2 O 3 -SEP can maintain its catalytic efficiency after six recycling runs. Characterization studies revealed that a high mesoporous specific surface area and a high ratio of Brønsted and Lewis acid sites are beneficial to enhancing the activity of the catalysts. In addition, a possible catalytic mechanism for CO 2 desorption was proposed. As a result, this work proved that SEP has the potential to be a low-cost and competitive catalyst carrier for CO 2 capture.

An investigation on the effects of organic additives on CO2 capture performance of Na2CO3 solution

“…To explore the promotional effect of TBAB in Na 2 CO 3 solution, FT-IR and 13 C NMR tests were used to analyze TBAB/Na 2 CO 3 solution samples before and after CO 2 absorption.…”

“…On this base, the infrared spectra of absorbent samples were obtained by selecting the transmission mode with 32 repetitions of scanning in the wave number range of 600-4000 cm −1 and 4 cm −1 resolution. Reaction products in the absorbent after CO 2 absorption were identified by 13 C NMR. D 2 O was chosen as a deuterium reagent and tetramethylsilane (TMS) was used as an internal standard in the test.…”

“…[8][9][10] But they still face some challenges including high investment and operation cost, especially high energy consumption during regeneration. [11][12][13] Besides, there are some other drawbacks limiting their large-scale application, such as the generation of poisoning by-products, evaporation loss of alkanolamine, together with corrosion from alkaline aqueous solution in high-temperature regeneration process. By contrast, carbonate solution seems a promising CO 2 absorbent due to its low cost, non-corrosion, low toxicity, and good thermal stability.…”

“…Furthermore, the regeneration behavior of additive/Na 2 CO 3 solution at different desorption temperatures was investigated, and the stability of absorbent during cyclic absorption-desorption was studied. Finally, the regeneration energy consumption of Na 2 CO 3 solutions with additive introduction was evaluated, and the possible reaction mechanism for CO 2 capture by the additive-promoted Na 2 CO 3 solution was explored by FT-IR and 13 C NMR characterization.…”

“…Due to their high selectivity and absorption ability, organic amine solvents such as Monoethanolamine (MEA) and N‐Methyl monoethanolamine (MDEA), are commonly used as alkaline solutions to absorb CO 2 8‐10 . But they still face some challenges including high investment and operation cost, especially high energy consumption during regeneration 11‐13 . Besides, there are some other drawbacks limiting their large‐scale application, such as the generation of poisoning by‐products, evaporation loss of alkanolamine, together with corrosion from alkaline aqueous solution in high‐temperature regeneration process.…”