Low-Viscosity Nonaqueous Sulfolane–Amine–Methanol Solvent Blend for Reversible CO₂ Capture

Abstract

In this work, the absorption−desorption performance of CO 2 in six new solvent blends of amine (diisopropylamine (DPA), 2amino-2-methyl-1-propanol (AMP), methyldiethanolamine (MDEA), diethanolamine (DEA), diisopropanolamine (DIPA), and ethanolamine (MEA)), sulfolane, and methanol has been monitored using ATR-FTIR spectroscopy. Additionally, NMR-based species confirmation and solvent viscosity analysis were done for DPA solvent samples. The identified CO 2 capture products are monomethyl carbonate (MMC), carbamate, carbonate, and bicarbonate anions in different ratios. The DPA solvent formed MMC entirely with 0.88 mol CO2 /mol amine capture capacity, 0.48 mol CO2 /mol amine cyclic capacity, and 3.28 mPa•s CO 2 -loaded solvent viscosity. MEA, DEA, DIPA, and MDEA were shown to produce a low or a negligible amount of MMC while AMP occupied an intermediate position.

Recent Progress on CO2 Capture Based on Sterically Hindered Amines: A Review

“…However, at a loading of 0.88 mol CO 2 /mol amine, the viscosity of the nonaqueous SHA absorbent DPA-methanolsulfolane increased only slightly from 1.02 mPa•s (unloaded) to 3.28 mPa•s (loaded) at 40 °C, which is comparable to the viscosity of 30 wt % MEA absorbent (1.7−2.7 mPa•s). 19,158 Ma et al 151 introduced AMP as a modulator to the nonaqueous amine absorbent DA2MP-PrOH to regulate the high viscosity of its saturated absorbent in their experiments. Prior to the addition of AMP, the products consisted of DA2MP-carbamate that was engendered through the process of self-deprotonation of DA2MP-zwitterion, a compound that exhibited formidable hydrogen bonding and pronounced polarity, thus rendering it challenging to dissolve in solvents.…”

“…155 The potential of methanol as one of the constituents in hybrid solvents is studied to reduce the cost of regeneration, owing to its low heat capacity, low boiling point, and low viscosity compared to water. 156 Wagaarachchige et al 19 investigated nonaqueous solvents sulfolane and methanol for CO 2 capture which could regenerate at a low temperature. The CO 2 absorption and desorption of the nonaqueous amine absorbents DPA/AMP/DEA/DIPA/MEA-sulfone-methanol were investigated and monitored by ATR-FTIR spectroscopy, where DPA and AMP were SHAs.…”

“…The emission of an inordinate quantity of greenhouse gases into the atmosphere has been recognized as a significant instigator of worldwide climate alteration. − Carbon dioxide (CO 2 ) is one of the most prominent greenhouse gases. − The emission of CO 2 into the atmosphere is a major environmental concern as it has a direct impact on the rising temperatures of the planet. − As per the statistics published by the International Energy Agency, the worldwide CO 2 emissions stemming from energy utilization surged to an all-time high of 36.3 billion tons in 2021, which marks a 6% rise in contrast to the figures for 2020 . Fossil fuel combustion is responsible for more than two-thirds of the world’s net CO 2 emissions for electricity and heat production. − The implementation of carbon capture, utilization, and storage (CCUS) is widely regarded as a pivotal technology in mitigating CO 2 emissions by the year 2050. − As shown in Figure , CCUS involves the capture of CO 2 from sources like power plants and industrial processes, followed by the storage of CO 2 in underground geological formations or the utilization of it for other purposes such as enhanced oil recovery. − According to the location of CO 2 capture, there are precombustion capture, oxygen-rich combustion, and postcombustion capture. − Precombustion capture technology has high equipment investment costs and complex systems; oxygen-enriched combustion technology has high energy consumption in the oxygen production process. Postcombustion capture technology necessitates solely the adjustment of the tail gas treatment system of the power plant, thereby incurring measly modification expenses and exhibiting favorable adaptability to the power plant, rendering it a fitting option for retrofitting extant power plants. − Capturing CO 2 after combustion is seen as an essential measure toward decreasing worldwide emissions of CO 2 generated by the combustion of fossil fuels. − …”

Development of Novel Amp-Based Absorbents for Efficient Co2 Capture with Low Energy Consumption Through Modifying the Electrostatic Potential

“…In CO 2 capture process, the high energy cost is primarily due to the regeneration of absorbents [28]. In this work, CO 2 capture was conducted in a microwave swing system.…”

“…The addition of ethanol or 1-propanol as buffer solvents could effectively reduce the viscosity of the absorbents. Their results showed that these two absorbents had high loading capacities around 0.9 mol (CO 2 )/mole (Amine) and could be regenerated under 80-90 • C. Wagaarachchige et al [28] proposed a low-viscosity non-aqueous binary solvents blend for reversible CO 2 capture. In their study, nonaqueous diisopropylamine (DPA) solutions were prepared by mixing 30 wt% DPA, 35 wt% methanol, and 35 wt% sulfolane.…”