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Chemical absorbents with low-energy requirements have become the primary focus of the research on CO2 capture from flue gas in power plants. To verify the absorption performance of the NICE absorbent developed by the National Institute of Clean-and-Low-Carbon Energy in China, a performance optimization test was conducted in Zhejiang University's pilot-scale platform, and the effects of the liquid–gas ratio, regeneration pressure, rich liquid fractional flow, and interstage cooling on the absorption performance and regeneration energy consumption were investigated. The results showed that in the CO2 pilot test, the optimized minimum regeneration energy consumption was 2.85 GJ/t CO2, and the corresponding process parameters were as follows: a liquid–gas ratio of 1.82 L/m3, regeneration pressure of 191 kPa, an interstage cooling temperature of 40 °C, and a rich liquid fractional flow ratio of 0.18. This study preliminarily verified the low-energy consumption performance of the NICE absorbent and showed its good potential for industrial applications. Additionally, the NICE absorbent showed promise for capital and operating cost savings because of its low liquid–gas ratio. [ABSTRACT FROM AUTHOR]

An experimental-scale electrostatic precipitator (ESP) was built to investigate the influence of temperature and gas media on collection efficiency and energy consumption. High temperature was harmful to the performance of the ESP and had a considerable influence on large particles. The maximum collection efficiency was lower and energy consumption was higher under coal pyrolysis gas media than under air. Two improvement methods, namely, gas media conditioning and positive polarity power supply, were studied in this work. Both methods can improve the performance of high-temperature ESP under coal pyrolysis gas media. The improvement in collection efficiency under the effect of gas conditioning decreased and that under the effect of a positive power supply increased with the increase in temperature. Gas conditioning and positive power supply increased the maximum collection efficiencies of the ESP at 600 °C under coal pyrolysis gas media by 3.0% and 11.8%, respectively. Unlabelled Image • High temperature was harmful to the performance of the ESP. • The performance of ESP in coal pyrolysis gas is inferior to that in air. • Gas conditioning and positive power supply can improve the performance of ESP. [ABSTRACT FROM AUTHOR]

• Novel alkanolamine-based biphasic solvent with low regeneration energy and viscosity is proposed for CO 2 capture. • Tertiary amine 3-(dimethylamino)propan-1-ol(3DMA1P) is firstly introduced to decrease regeneration energy. • Phase separation mechanism is revealed by NMR and LogP analysis. • Molecular dynamics simulation is applied to study liquid structure and monitor the phase separation process. Biphasic solvents for CO 2 capture have received significant attention due to their potential for energy conservation. However, traditional biphasic solvents result in highly viscous CO 2 rich-phases and high amine losses. To overcome these drawbacks, we have developed a novel alkanolamine-based biphasic solvent by blending 2-(methylamino) ethanol (MAE), 3-(dimethylamino)propan-1-ol (3DMA1P), diethylene glycol dimethyl ether (DGM), and water. The aqueous MAE/3DMA1P/DGM solvent showed a cyclic capacity of 0.45 mol CO 2 /mol amine, which is 1.8 times that of monoethanolamine (MEA), and a desorption rate and regeneration efficiency twice those of MEA. The viscosity of the biphasic solvents can be reduced to 13.12 mPa⋅s at 313 K, which is lower than that of reported biphasic solvents. The evaluated regeneration energy was 2.33 GJ/ton CO 2. Cation chromatography measurements revealed the tendency of MAE to accumulate in the CO 2 -rich phase with increasing CO 2 absorption loading. Quantitative 13C NMR analyses were performed to investigate the species distribution in both phases, and DGM was found to be the major component of the CO 2 -lean phase. Different solubilities of the MAE molecules and MAE carbamate in DGM resulted in phase separation. Molecular dynamics (MD) simulations on the CO 2 -unloaded and CO 2 -loaded solutions verified the phase separation mechanism. MAE molecules tended to cluster, and the interactions between MAE and DGM dropped significantly, with increasing DGM concentration. [ABSTRACT FROM AUTHOR]

Highenergy consumption is a crucial issue for the regenerationof solvent for postcombustion CO2capture by chemical absorption.Primary modeling results show the potential to reduce the energy consumptionthrough a novel solvent regeneration process by direct steam stripping.This work is an extension of our previous exploration and aims tovalidate the direct steam stripping process by experimental studieson a lab-scale stripping platform. We investigated the direct steamstripping and the conventional stripping mode in terms of energy consumptionand steam condensation. The results showed, for the direct steam strippingmode, the optimum energy consumption at 1 atm was 2.98 MJ/kg CO2, 23.2% lower than that of the conventional stripping mode.Higher solvent feeding temperature and carrier steam superheatingtemperature were beneficial to reduce steam condensation in the column.We found 96–99.5 °C feeding solvent temperature was suitableconsidering both the energy consumption and steam condensation. Besides,we proposed an improved direct steam stripping process using carriergases such as hydrocarbon, which could further reduce the latent heatrequired. [ABSTRACT FROM AUTHOR]

Abstract: The novel regeneration process by using membrane vacuum technology was put forward to reduce the regeneration energy consumption in the chemical absorption process for CO2 separation from flue gas. The rich MEA solution was flowed in the lumen of the hydrophobic PP hollow fiber membrane contactors, and the shell side was maintained at a reduced pressure by a vacuum pump. In addition, the additional low temperature steam whose temperature is the same to rich MEA solution was also provided to act as the sweep gas to improve the regeneration performance and to prevent the water loss of the lean solution. Results showed that this membrane vacuum regeneration process can regenerate rich MEA solution to reach a relatively better regeneration performance and can effectively utilize the low temperature energy or waste heat in the power plants. [Copyright &y& Elsevier]

Abstract: The novel regeneration concept by using reduced thickness and vacuum technology was put forward in this paper to solve the higher regeneration energy consumption in the chemical absorption process for CO2 separation from flue gas. A 120-mm I.D. vessel was precisely designed to regenerate the CO2-rich solution, and the change of the thickness of thin-layer solutions was simulated by controlling the volume of rich solution added into the vessel. The experimental results show that vacuum regeneration may be viable if the CO2-rich solution can be easily partitioned into the continuous single thin-layer solutions with an appropriate thickness. The great decrease of thin-layer solution thickness and regeneration pressure, and the increase of liquid temperature can improve the regeneration performance considerably. In addition, it is worthy to determine the optimum initial CO2 loading of rich solution, regeneration time and absorbent concentration due to the contradiction between the CO2 loading of lean solution and regeneration energy consumption per kg of CO2. Finally, the simple comparison between vacuum and heating regeneration methods shows that the novel regeneration method may have the potential to reduce the regeneration energy requirement. [Copyright &y& Elsevier]

• The world's largest carbon capture projects from flue gas of coal power plants of Shengli oilfield 2 million tons/year of flue gas CO 2 capture project is introduced. • The blend amine absorbent performance, chemical absorption process, energy-saving method, and the layout area of engineering were interpreted. The health, safety, and environmental affect was analyzed and economic analysis was also carried out. The conclusion showed that the project has technical and economic feasibility. It is a comprehensive introduction of large-scale CO 2 capture process and parameters. • 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 2.2 GJ/tCO 2. • The level of total energy consumption is advanced in the world. The study showed that the total energy consumption per unit product is 121.4 kg (standard coal equivalent (SCE))/tCO 2 , which reduces the net CO 2 emission by 1.3687 million tons per year. The world's largest 2 million tons/year CO 2 capture project from flue gas of coal power plants for EOR at Shengli oilfield of China was introduced. The blend amine absorbent performance, chemical absorption process, energy-saving method, and the layout area of engineering were interpreted. The health, safety, and environmental affect was analyzed and economic analysis was also carried out. The conclusion showed that the project has technical and economic feasibility. The study showed that the total energy consumption per unit product is 121.4 kg (standard coal equivalent (SCE))/tCO 2 , and the comprehensive regeneration energy consumption of the project is less than 2.2GJ/tCO 2. The total investment of the project is 1329.4 million CNY; the after-tax internal rate of return reaches 8% when the ex-factory price of CO 2 is 301.84 CNY /t(excluding tax). [ABSTRACT FROM AUTHOR]

[Display omitted] • The ILs biphasic absorbent [TEPAH][CPL]/EG/DGDE was developed for CO 2 capture. • Phase separation was due to polarity change of the absorbent after CO 2 absorption. • The regeneration energy consumption is 51% lower than that of 30 wt% MEA solution. • The absorbent showed obvious low-corrosive advantage since the absence of H+. To achieve low regeneration energy consumption and low corrosion, a novel ILs nonaqueous biphasic absorbents composed of Tetraethylenepentamine (TEPA) Caprolactam (CPL), Ethylene glycol (EG), and Diethylene glycol dimethyl ether (DGDE) have been proposed for CO 2 capture. The maximum CO 2 loading of the optimal absorbent ([TEPAH][CPL]/EG/DGDE) could reach 1.88 mol·mol−1, with 40 % of the saturated phase volume containing 98 % of the mass percentage of CO 2 products. Furthermore, the regeneration energy consumption was only 1.88 GJ·t−1 CO 2 , approximately 51 % lower than that of 30 wt% monoethanolamine (MEA) aqueous solution. 13C NMR analysis has shown that the amino group on the cation [TEPAH]+ reacted with CO 2 to form CO 2 products-carbamate, and the anion [CPL]- assisted the proton transfer during the reaction. Combined with the results from quantum chemical calculation, the phase separation behavior of the absorbent was mainly due to the polarity difference between the CO 2 products and the solvent. Additonally, [TEPAH][CPL]/EG/DGDE was non-corrosive to 20# carbon steel before and after CO 2 absorption, and exhibited superior stability than MEA aqueous solution. [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]

Abstract Carbonation curing to produce building products could provide a promising route to energy-efficient cementation process and economic CO 2 sequestration. The potential benefit from material selection and optimization should be explored to optimize the environmental performance of CO 2 -cured materials. In this study, the accelerated mineral carbonation of wollastonite-Portland cement (WPC), a low carbon binder, is investigated by combining a detailed study on its CO 2 mineralization capacity and on the physicochemical evolution in microstructure. Up to 25 wt.% of natural wollastonite is employed to replace the CO 2 -intensive ordinary Portland cement. During the carbonation curing process, WPC pastes exhibited CO 2 uptakes up to 20 wt.% under moderate pressures (≤2.5 MPa). Also, a dense structure with substantially high polymerization degree and fine pores was clearly discerned in cured WPC paste. The pore-creating effect from evaporated pore water and the porosity-filling effect from carbonated calcium silicates were found to dominate the microstructure in the early-stage and mid-late stage reactions, respectively. Results also revealed the positive impacts of adding the wollastonite mineral: (i) The diluted effect of wollastonite enhanced the pore-creating effect in the early-stage; (ii) The consumption of wollastonite and formation of Ca-modified silica gel primarily happened in the mid-late stage, which helped increasing the degree of polymerization. Associated with the structural evolution, the cured WPC pastes exhibited superior compressive strength (over 80 MPa) after the carbonation curing: the maximum increment could exceed 350%. These results demonstrate the feasibility of CO 2 mineralization of WPC to produce green building material without compromising mechanical performance. Graphical abstract Image 1 Highlights • CO 2 mineralization of wollastonite-Portland cement (WPC) is proposed for concrete curing. • WPC containing 5–25% of natural wollastonite show considerable CO 2 uptake capacity. • Dominating effects controlling the evolution of pore structure are revealed. • CO 2 mineralization of wollastonite remarkably enhances the compressive performance. [ABSTRACT FROM AUTHOR]

Using an inert, immiscible organic component as the purging gas is an innovative technology in the CO 2 stripping process. It allows stripping at a lower temperature and overcomes the inherent problem of high energy consumption in steam-based CO 2 stripping processes. This work focused on developing a novel, direct non-aqueous gas stripping process and exploiting its potential for energy saving through experiments. An elaborate pre-screening of carrier gases was conducted through hydrocarbon, alcohols, aldehydes, ketones, and their isomers, etc. Pentane, hexane, and cyclohexane were selected as the carrier candidates for their good immiscibility with water/amine, low vaporization energy, mild condensation conditions, and low toxicity. The effects of carrier gas category, carrier gas flow rate, and rich solvent feeding temperature on the stripping performance were investigated. Pentane was found to be the superior carrier gas due to its low heat of vaporization, high regeneration rate, and low energy requirement. A unique phenomenon of water evaporation from the solvent was discovered in the organic gas stripping process, providing a promising approach to break the gas-liquid interface for enhanced diffusion kinetics. The feasibility of low temperature CO 2 stripping was analyzed by varying the rich solvent feeding temperature (70–100 °C). With pentane as the stripping gas, it was interesting to find an optimum rich-feed temperature lower than 90 °C, indicating great potential for a reduction in the overall energy requirement. Under the optimal conditions, the energy consumption during CO 2 regeneration, using pentane as the carrier gas, was 2.38 GJ/t CO 2 , 38.8% lower than that of the conventional stripping process. Furthermore, parasitic issues, such as water loss and solvent loss, were discussed. An improved direct non-aqueous gas stripping process with two-stage compression was used to tackle the carrier gas recovery problem. The simulation results show that more than 98% of the carrier gas can be recovered through preliminary separation approaches. [ABSTRACT FROM AUTHOR]

• LCA of transformation from a power plant to a polygeneration plant was conducted. • The complete transformation scenario even performed better than IGCC and USC. • The complete transformation increased the energy efficiency by 15.71 percent. • Coal transport will noticeably weaken the improvement effect of transformation. • This paper provided a new idea for the upgrading of small coal-fired power plants. Coal-fired power plants retirement is a worldwide problem due to the universal desire to control temperature increase less than 2 °C. Chinese government has also made clear plans to develop renewable electricity gradually in place of coal-fired electricity. The first to be affected are the small power units, which suffer from decreased operation hours and environmental protection problems simultaneously. The two possible fates of these small power plants are to be decommissioned or to be retrofitted into more advanced energy systems. Recently, we transformed a sub-critical power plant into a polygeneration plant using the dual fluidized bed pyrolysis technology and proposed two transformation methods, including the partial and complete transformation. A life cycle assessment (LCA) of the three scenarios, including two transformation scenarios and the original power plant scenario, is also performed to assess the transformation effect. The life cycle results are also compared with that of the ultra-supercritical (USC) unit and the integrated coal gasification combined cycle (IGCC) unit. As a result, 3600 MJ of energy output is adopted as the function unit. The LCA analysis indicates that the complete transformation for polygeneration is the best of all the five scenarios in view of almost all impact categories (CML 2001) and energy utilization performance. Compared with the original sub-critical power plant, the complete transformation can reduce greenhouse gas emissions by 36.5 percent. Besides, the complete transformation can also reduce acidification potential by up to 50.1 percent relative to IGCC. Moreover, the net energy efficiency of the complete transformation scenario is 3.65 percent higher than that of USC technology. Therefore, the current study may demonstrate the feasibility of transformation from the existing power plants to the polygeneration plants to achieve the goal of cleaner production, which may also provide a new idea for the upgrading of small power plants. [ABSTRACT FROM AUTHOR]