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• A modified ESP model suitable for high temperature gas was established. • The effect of temperature on ESP performance was investigated numerically. • An optimized ESP with assistant electrodes was developed and compared with the conventional ESP. High-temperature electrostatic precipitators (ESPs) are a potentially effective technology for purifying high-temperature gases. In this study, a comprehensive numerical model was developed to investigate the electric field and particle migration characteristics of an ESP at temperatures ranging from 400 to 600 °C. Moreover, an optimized ESP with assistant electrodes for improved high-temperature particle capture was proposed. The electric field, flow field and particle capture characteristics of the two types of ESPs were compared to demonstrate the superiority of the optimized ESP. Results indicated that high temperatures had a negative impact on ESP performance. As the temperature increased, the operating voltage of the ESP decreased, leading to decreases in both the electric field strength and space charge density. The effective migration velocity of the particles also decreased with increasing temperature, and the inhibitory effect of high temperature on particle capture increased with increasing particle size. The optimized ESP with assistant electrodes exhibited more favorable electric field and flow field characteristics for particle capture compared to those of the conventional ESP. The optimized ESP exhibited higher electric field strength, which increased the electric field force on the particles and promoted particle capture. Meanwhile, the space charge density of the optimized ESP was lower, effectively inhibiting the occurrence of back corona. Moreover, the optimized ESP enhanced the ionic wind downstream of the discharge electrode, thereby promoting particle migration towards the collection electrode. Consequently, the ESP with assistant electrodes effectively improved the collection efficiency. [ABSTRACT FROM AUTHOR]

[Display omitted] • Using alkanolamine to regulate the viscosity of biphasic solvents is proposed. • A novel polyamine-based biphasic solvent with low costs is developed. • The phase split mechanism is investigated by NMR analysis. • A molecular-scale understanding of the viscosity regulation mechanism is revealed. Biphasic solvent has attracted widespread attention in CO 2 chemical absorption technology due to its significant potential for reducing capture energy consumption. However, the high viscosity of CO 2 -rich phase after phase split could lead to issues such as high flow resistance, low heat transfer efficiency, and phase separation instability in application. To address these limitations, a strategy of using alkanolamine as a viscosity regulator for biphasic solvents was proposed. Diethanolamine(DEA), an alkanolamine regulator, was introduced to a system of polyamine/amide absorbent, and then a novel biphasic solvent of diethylenetriamine (DETA)/diethanolamine(DEA)/N, N-Dimethylacetamide(DMAC)/water(H 2 O) was developed. The viscosity of the CO 2 -rich phase solvent was reduced to 19.02 mPa⋅s, a significant decrease compared to the solution without DEA regulation. The novel solvent exhibited a high cyclic capacity of 2.08 mol/kg, which was 43.4 % higher than that of the solution without DEA, and a desorption rate twice as high as 30 wt% monoethanolamine(MEA). Quantitative 13C Nuclear Magnetic Resonance (NMR) and Molecular Dynamics (MD) simulations revealed the phase split and viscosity regulation mechanisms. It was proved that DETA species, especially carbamates, tend to self-aggregate with each other due to intermolecular hydrogen bonding with the CO 2 loading increases, which leads to phase split and high viscosity of the saturated solution. Through DEA regulation, the protonation of carbamates and the generation of HCO 3 –/CO 3 2– were promoted, which weakened the self-aggregation of carbamates species, decreasing the viscosity and the regeneration energy of saturated CO 2 -rich phase solution. The regeneration energy reached 2.19 GJ/ton CO 2 , which exhibited a 42.4 % reduction compared with that of 30 wt% MEA. [ABSTRACT FROM AUTHOR]

• We proposed a novel desorption process based on ion exchange for CO 2 sorbents. • The sorbents were demonstrated with high working capacity and improved desorption kinetics. • Key factors of kinetics improvement were discussed among optimization of the OH–/HCO 3 – ratio at inlet, concentration, and external diffusion. • The solution after desorption (ion exchange) could be regenerated through an electrochemical DAC system to utilize renewable energy efficiently. To satisfy the Paris Agreement's 1.5 °C goals, direct air capture (DAC) has become an increasingly crucial technology. However, the ultralow partial pressure of CO 2 in ambient air contributes to a low desorption rate and high regeneration energy consumption. In this study, we proposed a fast regeneration method for CO 2 sorbents based on an ion exchange process. Utilizing an alkaline solution rich in hydroxide (OH–) ions, the quaternary ammonium (QA)-based ion exchange resin can be changed from carbonate (CO 3 2–) to OH– form, which directly captures CO 2 from ambient air. The results showed that the working capacity of the sorbents in the OH– form was 1.85 mmol⋅g−1, which was double that of the CO 3 2– form (0.88 mmol⋅g−1). The kinetics showed that the ratio of OH–/HCO 3 – at inlet, concentration, and external diffusion influence the desorption rate of CO 3 2– because of the ion exchange reaction. With a high ratio of OH–/HCO 3 – at inlet, 1 M alkaline solution, and 3 mL⋅s−1 cyclic flow rate, the desorption time of the sorbents was approximately 20 min. Finally, because the energy consumption of the entire process comprises mainly electric energy required to regenerate the alkaline solution after ion exchange, it is expected to establish an electrochemical DAC system to utilize renewable energy efficiently. [ABSTRACT FROM AUTHOR]

• China has implemented a huge CO 2 capture project, the 150,000 tons/year CO 2 capture and purification project of Shaanxi Guohua Jinjie Power Plant, which is the largest flue gas capture project in China. • The energy consumption level of regeneration reaches the leading level of flue gas CO 2 capture demonstration project. New energy-saving process of "interstage cooling + MVR heat pump + desorption heat energy recovery" is applied, and comprehensive regeneration energy consumption is less than 2.4GJ/tCO 2. • The final research results show that the project has technical feasibility and economic feasibility. The results show that the regeneration energy consumption per unit product is 2.32GJ/tCO 2 , and the loss of absorbent is less than or equal to 1.0 kg/tCO 2. There was little research and demonstration experience in large flue gas carbon projects in China. 150 kt/a flue gas CO 2 capture project in the Guohua Jinjie power plant, which is the largest-scale flue gas carbon capture project in China, effectively solved this technical bottleneck. The performance of the used compound amine absorbent, phase change absorbent, and the ionic liquid was described, and the compatibility of performance was considered in the project; new energy-saving processes integrated mechanical vapor recompression heat pump, interstage cooling, and split flow desorption. The plane layout of the project was put forward, and the utility consumption of the capture system was analyzed. The paper explained the health, safety, and environmental protection instructions, presented test category tables, and developed energy consumption and economic analyses. The results showed that the renewable energy consumption per unit product was 2.32 GJ/t CO 2 , the loss of absorbent was less than or equal to 1.0 kg/t CO 2 , and the total investment (excluding tax) of the project was 13.8398 million yuan. When the CO 2 sales price (excluding tax) was 203.43 Yuan/t, the yield was 0 %, and when the CO 2 sales price (excluding tax) was 260.949 Yuan/t, the yield was 8 %. The feasibility study research conclusions indicated that the project was technically and economically feasible. [ABSTRACT FROM AUTHOR]