International experience of carbon neutrality and prospects of key technologies:Lessons for China

Carbon neutrality(or climate neutrality)has been a global consensus,and international experience exchange is essential.Given the differences in the degree of social development,resource endowment and technological level,each country should build a carbon-neutral plan based on its national conditions.Compared with other major developed countries(e.g.,Germany,the United States and Japan),China's carbon neutrality has much bigger challenges,including a heavy and time-pressured carbon reduction task and the current energy structure that is over-dependent on fossil fuels.Here we provide a comprehensive review of the status and prospects of the key technologies for low-carbon,near-zero carbon,and negative carbon emissions.Technological innovations associated with coal,oil-gas and hydrogen industries and their future potential in reducing carbon emissions are particularly explained and assessed.Based on integrated analysis of international experience from the world's major developed countries,in-depth knowledge of the current and future technologies,and China's energy and ecological resources potential,five lessons for the implementation of China's carbon neutrality are proposed:(1)transformation of energy production pattern from a coal-dominated pattern to a diversified renewable energy pattern;(2)renewable power-to-X and large-scale underground energy storage;(3)integration of green hydrogen production,storage,transport and utilization;(4)construction of clean energy systems based on smart sector coupling(ENSYSCO);(5)improvement of ecosystem carbon sinks both in nationwide forest land and potential desert in Northwest China.This paper provides an international perspective for a better understanding of the challenges and opportunities of carbon neutrality in China,and can serve as a theoretical foundation for medium-long term carbon neutral policy formulation.

Simulation study of supercritical carbon dioxide jet fracturing for carbonate geothermal reservoir based on fluid-thermo-mechanical coupling model

Geothermal energy is a kind of renewable,sustainable and clean energy resource.Geothermal energy is abundant in carbonate reservoirs.However,low matrix permeability limits its exploitation.The super-critical carbon dioxide(SC-CO_(2))jet fracturing is expected to efficiently stimulate the carbonate geothermal reservoirs and achieve the storage of CO_(2) simultaneously.In this paper,we established a transient seepage and fluid-thermo-mechanical coupled model to analyze the impact performance of sc-CO_(2) jet fracturing.The mesh-based parallel code coupling interface was employed to couple the fluid and solid domains by exchanging the data through the mesh interface.The physical properties change of sC-CO_(2) with temperature were considered in the numerical model.Results showed that SC-CO_(2) jet frac-turing is superior to water-jet fracturing with respect to jetting velocity,particle trajectory and pene-trability.Besides,stress distribution on the carbonate rock showed that the tensile and shear failure would more easily occur by SC-CO_(2) jet than that by water jet.Moreover,pressure and temperature control the jet field and seepage field of sC-CO_(2) simultaneously.Increasing the jet temperature can effectively enhance the impingement effect and seepage process by decreasing the viscosity and density of SC-CO_(2).The key findings are expected to provide a theoretical basis and design reference for applying SC-CO_(2) jet fracturing in carbonate geothermal reservoirs.

Recent advances,challenges,and perspectives on carbon capture

Carbon capture,utilization and storage(CCUS)technologies play an essential role in achieving Net Zero Emissions targets.Considering the lack of timely reviews on the recent advancements in promising CCUS technologies,it is crucial to provide a prompt review of the CCUS advances to understand the current research gaps pertained to its industrial application.To that end,this review first summarized the developmental history of CCUS technologies and the current large-scale demonstrations.Then,based on a visually bibliometric analysis,the carbon capture remains a hotspot in the CCUS development.Noting that the materials applied in the carbon capture process determines its performance.As a result,the state-of-the-art carbon capture materials and emerging capture technologies were comprehensively summarized and discussed.Gaps between state-of-art carbon capture process and its ideal counterpart are analyzed,and insights into the research needs such as material design,process optimization,environmental impact,and technical and economic assessments are provided.

Experimental Investigation on the Performance of[APMIm][NTf_(2)]for Capturing CO_(2)from Flue Gas of the Cement Kiln Tail

Facing the global warming trend,humanity has been paying more and more attention to the Carbon Capture,Utilization and Storage.Large amounts of CO_(2)is emitted with burning fossil fuel as well as by some special industrial processes like the decomposition of calcium carbonate in a cement plant.The cement industry contributes about 7%of the total worldwide CO_(2)emissions and the CO_(2)concentration of flue gas of the cement kiln tail even exceeds 30%.Ionic liquid is considered to be an effective and potential material to capture CO_(2).In order to investigate the performance of ionic liquids for capturing CO_(2)from flue gas of the cement kiln tail,an experiment system was established and an ionic liquid,[APMIm][NTf_(2)](1-aminopropyl-3-imidazolium bis(trifluoromethylsulfonyl)imine),was tested using pure CO_(2)and simulated gas.The results showed that both physical and chemical absorption play roles while physical absorption dominates in the absorption process.Both the absorption capacity and rate decrease with raising the operating temperature.In the experiment with pure CO_(2),the absorption capacity is 0.296molCO_(2)⋅molIL−1 at 30℃ and 0.067molCO_(2)⋅molIL−1 at 70℃.Meanwhile,the ionic liquid can be regenerated for recycling without obvious changes of the absorption capacity.When the ionic liquid is used for flue gas of the cement kiln tail rather than pure CO_(2),a sharp decrease of the absorption capacity and rate was observed obviously.The absorption capacity at 30℃ dropped even to 0.038molCO_(2)⋅mol_(IL)^(−1),12.8%of that for pure CO_(2).Additionally,a natural desorption of CO_(2)from the ionic liquid was observed and affected the experimental results of the absorption capacity and the absorption-desorption rate to some extent.