Light spectrum regulation is an effective way to promote carbon fixation of haematococcus pluvialis. The carbon fixation capacity of haematococcus pluvialis was compared under different light conditions, and the effects of the mixed red and blue light with different spectral ratios on the carbon fixation performance of haematococcus pluvialis were studied. Gene expressions at different vegetative stages were compared to figure out the dynamic changes of haematococcus pluvialis metabolism on the time scale. The results show that, the carbon fixation rate in red light was 40% higher than that in blue light. By comparing the whole-genome transcriptome of the haematococcus pluvialis, the metabolic responses of the haematococcus pluvialis to different light qualities, including biomass accumulation, energy transfer, photosynthesis, stress and transcription, were analyzed at the molecular level. The metabolism and energy transfer of the haematococcus pluvialis were more active in red light than that in blue light. At the early growth stage, cells under the red light dominant condition tended to accumulate regulatory substances rather than energy storage substances, and genes involved in glycolysis/ gluconeogenesis pathway, tricarboxylic acid cycle (TCA) and AMP-activated protein kinase (AMPK) pathway were up-regulated. Cells under the blue light dominant condition performed better in stress response.

Due to the low-carbon transformation requirement of domestic coal power units in the “carbon peak and carbon neutrality” situation, exploring a new industrialization way in solid adsorption CO₂ capture technology on CCUS, and developing a new solid chemical sorbent to capture CO₂ from coal-fired flue gas, are important for realizing large-scale application of such technology. Current researches on solid adsorption CO₂ capture technology in China mainly focus on the theory level. This study systematically reviews and analyzes the research progress on solid sorbent materials at low, medium and high temperatures, points out the directions for further research, and identifies the research content needed for scaled application. A typical high-temperature calcium-based sorbent is used as an example to analyze the industrial applications of the entire process, including the sorbent preparation, sorbent scaling up, sorbent granulation and molding, reactor design, and CO₂ capture system verification for calcium looping. This study can provide references for aspects including further key technology research and breakthroughs, the construction of a full process for solid adsorption CO₂ capture with high activity and low energy requirement, and the realization of the large-scale application of solid adsorption CO₂ capture technology.

The TiO₂ surface is functionalized with different concentrations of K₂CO₃ and polyethyleneimine (PEI), and in-depth research on CO₂ adsorption performance and mechanism is conducted. CO₂ low-temperature adsorbent was successfully prepared by ultrasonic impregnation method using K₂CO₃ and PEI as functionalized materials and commercial selective catalytic reduction (SCR) catalyst white embryo (porous TiO₂) as carrier. The physicochemical properties of the modified adsorbents were characterized using X-ray diffraction (XRD), differential thermogravimetry (DTG), Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The results indicate that, K₂CO₃ and PEI activate the porous structure of TiO₂, enhancing the density of surface alkaline active sites. This enhancement facilitates the accommodation of PEI and K₂CO₃, exposes adsorption active sites, and promotes CO₂ diffusion and CO₂ adsorption. 50%PEI@TiO₂ introduces numerous active functional groups and alkaline amine sites, achieving a CO₂ adsorption capacity of 2.11 mmol/g. By measuring the CO₂ adsorption by 50%PEI@TiO₂ adsorbent and fitting to Langmuir and Freundlich adsorption isotherm models, it finds that CO₂ is mainly adsorbed physically, and van der Waals force plays a major role during adsorption. The optimal adsorption and desorption temperatures for CO₂ are 50 ℃ and 110 ℃, respectively. The cyclic experiment showed that, compared with PEI, K₂CO₃-loaded adsorbents exhibit greater stability, with a decrease in adsorption capacity of less than 10% after 30 cycles. These findings suggest that functionalized materials based on commercial SCR catalyst TiO₂ pellets hold promise for low-temperature CO₂ capture in industry flue gases.

Carbon capture, utilization and storage (CCUS) is a key technology to mitigate the impact of CO₂ emissions on the environment, and CO₂ geological storage and utilization is an important part of CCUS. This paper analyzes the global development trend of CO₂ geological storage and utilization technology, reviews the current development situation in China from the aspects of policy system construction, project implementation and research results, interprets the research frontiers in this field through literature analysis, and prospects the development of CO₂ geological storage and utilization. Current research focuses on the CO₂ geological storage and utilization in depleted oil and gas reservoirs, induced seismic mechanism and monitoring, leakage monitoring and environmental assessment, CO₂ geological storage and energy resources cooperative development and utilization, and rapid mineralization storage. In the future, research in this field should focus on the complex multi-field and multi-phase study in CO₂ geological storage and utilization, building a whole-process intelligent CO₂ geological storage and utilization system, and exploring diversified CCUS industry development models.

Xinjiang Zhundong coal has abundant reserves and contains a relatively high content of alkaline earth metal elements. The high-calcium fly ash generated from its combustion serves as an excellent raw material for CO₂ sequestration. By adopting the atmospheric pressure direct wet carbonation process, research and optimization analysis were carried out on the carbonation of high-calcium fly ash, focusing on key parameters such as flue gas flow rate, temperature, and solid-liquid ratio. A kinetic model was constructed to determine the key factors and rate-controlling steps. Meanwhile, the performance of this process in chlorine removal and heavy metal removal was evaluated. It was found that, increasing the flue gas flow rate and reducing the solid-liquid ratio can effectively enhance the degree of carbonation per unit mass of fly ash. During the rapid carbonation stage (0~20 min), low temperature is beneficial for increasing the degree of carbonation, but the effect is not significant. In the rapid carbonation zone, the reaction of fly ash is mainly controlled by solid-film diffusion, with a correlation coefficient of 0.917 37 and an activation energy of 10.36 kJ/mol. After optimization by the response surface method, the optimal operating condition parameters are as follows: temperature of 57.1 ℃, flue gas flow rate of 2.86 L/min, and solid-liquid ratio of 200.0 g/L. Under these conditions, the average actual degree of carbonation reaches 30.2%. The chlorine content of the fly ash processed according to these parameters meets the requirements for reinforced products in the JC/T 409—2016 standard. For typical heavy metals such as arsenic and copper, the removal rates reach 88.4% and 55.6% respectively, indicating that this process has a certain detoxification ability. Therefore, the atmospheric wet carbonation of high calcium fly ash in Zhundong has great potential for application.

With the launch and promotion of national carbon trading market, accurate carbon emission data of emission control enterprises is crucial for the government to formulate policies and build carbon trading mechanisms. The current official carbon emission accounting method in China, the emission factor method, is simple and easy to use, but is highly influenced by human factors and can easily lead to quality issues with carbon data. Therefore, a rapid analysis method for coal quality indicators suitable for coal-fired power plants in the carbon market is developed based on laser induced breakdown spectroscopy (LIBS) technology. Combined with partial least squares regression (PLSR), a predictive model for carbon content and heat generation of coal elements is established. The results show that, the average absolute error (AAE) of the prediction set for the established dry based high calorific value and carbon content model is 1.10 MJ/kg and 2.72%, respectively, which can achieve fast and high-frequency detection of daily coal samples in power plants. In the application research of carbon accounting, examples show that, compared with the conventional daily measurement method, the relative deviation of monthly carbon emissions accounting obtained by the LIBS rapid detection method for daily measurement is only 0.40%, which is more accurate than that obtained by the monthly reduced coal sample detection method. In the application research of carbon verification, based on the results of the element carbon content measurement method, the average relative error (ARE) of the carbon emissions calculated using the LIBS rapid detection method has a reduction of 6.73~18.99 percentage points compared with that using the complete default value method. The LIBS rapid detection method has a testing accuracy that is close to conventional laboratory results, which can be applied to carbon verification and coal quality data verification, and be developed into a fast and low-cost practical technology to assist carbon accounting.

Post-combustion carbon capture is the underpinning technology and necessary choice for low-carbon power generation, yet its integration into natural gas combined cycle (NGCC) power plants will significantly reduce the plants’ power generation efficiency. In order to reduce the efficiency penalty of the power plants integrated with decarbonization system and improve the energy utilization efficiency of the integrated system, a novel post-combustion carbon capture process that comprehensively recovers the waste heat and liquefied natural gas cold energy is innovatively proposed. Firstly, the key operating parameters of the conventional carbon capture process, including stripper pressure and lean solvent loading, are optimized with sensitivity analysis. On this basis, design and evaluation of novel process is performed. In the novel process, a back-pressure turbine is utilized to recover the pressure energy of the extracted low-pressure steam and assist the lean vapor compression as well as recover the inter-cooling heat of CO₂ compression to heat the reflux condensate of the stripper, which reduces the minimum regeneration energy consumption by 17.3% (to 3.35 GJ) at the flash pressure drop of 90 kPa. Furthermore, the extracted low-pressure steam is reduced from 68.40 kg/s to 48.95 kg/s by recovering the superheat of steam extraction. Aiming at solving the problems of high energy consumption of the conventional CO₂ compression process and the waste of cold energy in the liquefied natural gas regasification process, a novel CO₂ two-stage compression and intermediate liquefication process is proposed, reducing compression work by 34.5%, and the cooling load and the number of equipment were significantly decreased. Exergy analysis results show that the exergy efficiencies of the novel carbon capture process and CO₂ compression process increase from 23.12% and 62.19% to 29.48% and 65.96%, respectively. The simulation results show that, the net power output of the plant integrated with the novel carbon capture process increases from 341.93 MW to 358.75 MW, resulting in a significant energy saving by increasing the net power output efficiency from 48.85% to 51.25% and decreasing the efficiency penalty from 13.77% to 9.53%.

Direct air carbon capture (DAC) technology has been booming in the past decade, and now it has gradually developed from laboratory toward commercial device. Because the adsorption DAC is more promising than absorption DAC, some companies have launched DAC demonstration projects based on adsorption. However, there is relatively little introduction to these companies and projects based on adsorption DAC in current research, and a comprehensive study has not yet been formed. In view of the above reasons, some representative companies owning adsorption DAC technologies and their projects are investigated through existing literatures and their corporate websites, and the key contents are focused. In addition, the device types of these enterprises are divided into centralized devices and integrated devices according to the arrangement of equipment, and the characteristics of these two types of devices are introduced. By summarizing the characteristics of DAC enterprises and technologies, it is found that most enterprises are committed to reducing operation and investment costs, so the possible cost reduction methods in the future industrialization process are put forward and the effects are analyzed.

Post-combustion capture is a bottom-up technology for achieving carbon neutrality, but the high costs associated with carbon capture are detrimental to the application of this technology. In order to investigate the sensitivities to changes in the cost of carbon capture, compression and liquefaction, the costs incurred by different process parameters and absorbent types were modelled. The results show that, increasing the number of plates in the absorption tower promotes the efficiency of CO₂ capture by absorbent, with a corresponding rise in investment costs. The increase of absorber temperature at the inlet of the absorber tower does not show a significant decrease in capture rate, but the reduction of coolant and water usage reduces the operating cost to a certain extent. In addition, the reboiling ratio has the greatest influence on the CO₂ capture rate and cost, which may be the key factor for cost reduction. At the same time, the energy consumption of the system with different liquefaction pressures and different numbers of compression stages was compared, and it is found that the lower the liquefaction pressure and the higher the number of compression stages, the higher the total cost, and the equipment investment cost and operation and maintenance cost changes more obviously, while the utility costs are less affected.

Carbon capture, utilization and storage technology is an important way to realize the carbon peaking and carbon neutrality goals in China. Among them, the non-aqueous phase absorbents have great energy-saving potential, and it is suitable for the existing mixed amine reactor, which has a large development potential. However, there are still problems such as high viscosity of CO₂ saturated solution and low circulating load. In this regard, a non-aqueous absorption system with low viscosity and regeneration temperature was constructed using secondary amine MCA as the absorbing component and EG as the organic solvent. The absorption and regeneration performance of MCA/EG was investigated. The results showed that, the absorption load of 3 mol/L MCA/EG solvent was up to 2.14 mol/L, and the viscosity was only 44.19 mPa∙s. Under the condition of absorption at 40 ℃ for 30 min and regeneration at 80 ℃ for 25 min, the cyclic load was as high as 0.98 mol/L, which is 1.46 times of the cyclic load of 30% MEA/H₂O solution at 105.5 ℃. The reaction heat of the absorbent was measured to be -82.85 kJ/mol by C80 microcalorimeter, which was lower than that of the MEA/H₂O solution. The reaction mechanism of CO₂ capture by MCA/EG was explored by ¹³C NMR and quantum chemical calculations. It was found that the stability of the reaction products was reduced for the steric hindrance effect of MCA. The carbamates transform into alkyl carbonate by reacting with EG to realize the regeneration at low temperatures. MCA/EG can realize the stable operation of non-aqueous phase absorbent and expand the scope of waste heat utilization in absorbent regeneration, which has a great advantage of energy reduction.