Abstract:Carbon capture,utilization,and storage(CCUS)has emerged as a pivotal technology in combating climate change,garnering significant attention worldwide.However,despite its potential,CCUS commercialization faces numerous challenges,including technological advancements,cost-effectiveness,policy frameworks,business models,and public acceptance.With a focus on coal-fired power plants,this study delves into the investment decisions surrounding CCUS under the integrated"carbon capture-utilization-storage"business mode.Drawing upon the real option theory,we formulate an investment decision model that accounts for the uncertainty of carbon prices and the diminishing cost of CCUS ventures.Additionally,we assess the impact of carbon price volatility and various incentive policies such as extra power quota,electricity price subsidy,and investment subsidy on the investment decisions of coal-fired power plants.Our findings highlight several key points:① Higher CO2 utilization rates favor better CCUS investments.When the CO2 utilization rate is higher than 47.27%,coal-fired power plants can invest immediately;② Stable carbon prices positively influence CCUS investment promotion;③ Electricity price subsidy proves to be the most effective incentive policy.

Abstract:Coal-fired power plants are an important part of the global energy supply and also a major source of greenhouse gases such as carbon dioxide,exerting a profound impact on climate change.Accurately quantifying the carbon emissions from coal-fired power plants is a key technical challenge in achieving the"dual carbon"goals.Only through reliable emission quantification methods can the emission base be accurately grasped and effective emission reduction paths be formulated.In recent years,machine learning technology,with its powerful data modeling and prediction capabilities,has provided a new solution to this difficult problem.For this reason,this article briefly summarizes the development history and classification of machine learning technology,and systematically reviews the application progress and cutting-edge directions of machine learning technology in the research of carbon emissions from coal-fired power plants.Firstly,in view of the limitations of insufficient real-time performance of traditional accounting methods and high cost and low coverage of continuous Emission Monitoring Systems(CEMS),this paper discusses how the Predictive Emission Monitoring System(PEMS)can achieve real-time prediction and data repair of carbon emissions through machine learning.Secondly,the electricity-carbon model based on power big data and machine learning technology were analyzed,and the application potential of Non-Intrusive Load Monitoring(NILM)in multi-device refined carbon emission decomposition was explored,significantly improving the interpretability of emission sources.Finally,by integrating satellite remote sensing and machine learning,wide-area inversion and outlier reconstruction of CO2 emissions from coal-fired power plants were achieved,verifying the complementarity between satellite monitoring and ground-based inventories.Relevant studies have shown that machine learning has promoted the development of carbon emission monitoring towards real-time and intelligence through the integration of multi-dimensional technologies(PEMS-electricity-carbon model-satellite remote sensing),but it still faces challenges such as model generalization and interpretability.In the future,it is necessary to strengthen the collaborative innovation of physical models and data-driven approaches,and build an integrated monitoring system of"air-space-ground"to provide technical support for the low-carbon transformation of global coal-fired power plants.

Abstract:CO2 capture from the flue gas of coal-fired power plants is an important part of China's goal of carbon pegging and carbon neutrality,and the key lies in the development of highly efficient CO2 adsorbents.However,water vapor and other impurities are inevitably present in the coal flue gas,which affects the structure of the adsorbent and the CO2 adsorption mechanism.Therefore,clarifying the influence of water vapor on the structure of adsorbents and the CO2 adsorption mechanism is the key to developing efficient and stable adsorbents.The effect of water vapor on the structure and CO2 adsorption mechanism of typical solid adsorbents(including solid amine,activated carbon,metal-organic framework,zeolite,MgO and CaO-based adsorbents)is discussed in detail.For hydrophilic adsorbents such as activated carbon and zeolite,CO2 adsorption is competed with by water vapor;For the adsorbents with regular pore structure such as metal-organic framework,the structure is destroyed and caused to collapse by water vapor.For solid amine adsorbents,the dehydration reaction is inhibited and the amine efficiency is changed by water vapor.For MgO and CaO-based adsorbents,the specific surface area,pore structure and CO2 molecular diffusion efficiency are affected by the presence of water vapor.Methods to optimize the structure of adsorbent include hydration reactivation,water vapor pretreatment,adjusting pore size and surface hydrophobic modification,etc.Among them,the hydration reactivation method is associated with large energy consumption and reduces the crush strength of the adsorbent.Therefore,the pore size adjustment method is considered to have limitations for adsorbents with developed and adjustable voids,while the surface hydrophobic modification method complicates the synthesis process,resulting in increased production costs..In the future,it is necessary to further explore the method of optimizing the modification of the adsorbent based on the influence of water vapor,achieve the reduction of energy consumption through process optimization,and enhance the crushing strength of the adsorbent by adding reinforcement materials and regulating hydration conditions.

Abstract:Under the strategic goal of"dual carbon",Carbon Capture,Utilization,and Storage(CCUS)is a key pathway to achieving green,low-carbon,and sustainable development.Among various CCUS approaches,electrochemical CO2 reduction(CO2ER)is considered highly promising.This technology uses clean electricity to directly convert captured CO2 into value-added chemicals—such as carbon monoxide,ethylene,and methanol—under ambient temperature and pressure.It not only enables the resource utilization of CO2 but also offers a practical way to integrate renewable energy,providing clear advantages over other carbon utilization methods.At present,research on CO2ER is still largely limited to the laboratory,and significant progress is needed for industrial application.Membrane electrode assembly(MEA)electrolyzers,a type of low-temperature CO2ER reactor,have advantages such as low ohmic resistance,compact design,and scalability,making them a promising option for large-scale CO2 electrolysis.However,scaling up MEA electrolyzers presents several major challenges.Their complex internal multiphase transport environment is prone to electrode"flooding"(liquid water accumulation at the cathode)and"salt precipitation"(salt crystallization at the cathode).These issues not only reduce catalyst stability but also hinder CO2 transport to active sites.As electrode size increases,uneven distribution of reactants,current density,and product concentration becomes more significant,both across the electrode surface and between stack units.In addition,heat buildup within the electrolyzer intensifies,posing risks to stable operation.This review begins with the basic working principles of CO2ER in MEA electrolyzers and systematically examines the key factors limiting their large-scale industrial deployment.It focuses on four main areas:long-term catalyst durability,operational stability of the electrolyzer,engineering scale-up from laboratory to industrial level,and system-level optimization through modeling.By integrating and analyzing the latest research advancements in this field,this paper aims to provide relevant references for the industrial development of CO2 electrolysis.

Abstract:The coal-based humic acid-based graphitized carbon(HAGC)was prepared from coal humic acid using carbonization-high temperature graphitization process.The study focuses on the effect of graphitization temperature on the microstructure of humic acid-based graphitized carbon and explored its electrochemical energy storage properties as an anode material for lithium-ion batteries(LIBs).The results demonstrated that the coal-based humic acid-based graphitized carbon coexisting graphite microcrystalline structure and amorphous structure can be prepared from coal-based humic with different graphitization temperatures(2 200-2 800℃).The graphitization temperature is an important factor affecting the microstructural features such as graphitization degree,microcrystalline lamellae,nanopores and structural defects of coal-based humic acid-based graphitized carbon.When the graphitization temperature was 2 800℃,the graphitization degree of coal-based humic acid-based graphitized carbon HAGC-2800 reaches 78.6%,with long-range ordered graphite microcrystalline lamellar structure and abundant amorphous carbon such as nanopore,structural defects,etc.,and both of them are tightly combined with each other and overlap and coexist.The coal humic acid-based graphitized carbon showed excellent lithium storage performance when used as anode materials for LIBs,with a reversible capacity of 352 mAh/g at a current density of 50 mA/g,a reversible capacity of 175 mAh/g at a high current density of 2 000 mA/g,and a capacity retention of up to 116%after 400 cycles,which shows good multiplicative performance and excellent cycle stability,making it an ideal anode material for LIBs.The excellent lithium storage properties of coal-based humic acid-based graphitized carbon HAGC-2800 are closely related to its microstructure,which is rich in amorphous carbon such as graphite microcrystalline lamellae with nanopores and structural defects.

Abstract:Technical innovation is indispensable for driving the low-carbon transition of the cement industry.Bioenergy with carbon capture and storage(BECCS)emerges as a critical technology to facilitate carbon neutrality.Quantifying the technical potential and economic costs of BECCS application in the cement industry is of significant importance.Based on the china biomass-emission-sink matching model(C-BESMM),the potential application of BECCS in the cement industry by 2060 was assessed.The results show that to achieve net-zero emissions in existing cement facilities,the biomass consumption could reach 29 million tons/year and the volume of CO2 storage could reach 535 million tons/year by 2060,with cement plants integrating biomass blending and carbon capture generating approximately 42 million tons/year of negative emissions.Biomass consumption plays a crucial role in emission reduction before 2040,while carbon capture becomes the primary driver after 2040,with energy efficiency improvements contributing steadily throughout the period.Regions with high biomass consumption include Guangdong,Shandong,Yunnan,and Henan.Hebei,Henan,Liaoning,and Guangxi lead in CO2 capture.98%of the unit emission reduction costs are between-100-800 yuan/ton of CO2.Among them,about 4%can achieve negative costs.Provinces with relatively large amounts of negative-cost emission reductions include Hebei,Shandong.Improving the biomass blending ratio,enhancing the biomass utilization rate as energy,and expanding the types of available biomass are conducive to increasing the biomass utilization volume in the cement industry,which is more beneficial for cement plants in reducing residual emissions and achieving"net zero".

Abstract:The offshore geological storage and utilization technology for carbon dioxide(CO2)is crucial for China to achieving the national dual carbon goals.However,the technological development pathways and policy roadmap remain unclear.This study develops a multi-dimensional assessment framework,covering technological,economic and contribution-based aspects,which is tailored to the characteristics of offshore CO2 geological storage in China.The framework systematically evaluates the status,storage potential,and emission reduction contribution of CO2 storage in offshore saline aquifers and oil fields towards realizing these dual carbon objectives,while proposing corresponding technological development pathways.The results indicate that the technology readiness level of offshore CO2 storage technologies in saline aquifers and oil fields in China ranges between levels 3 and 4.This highlights a considerable gap before commercial demonstration and large-scale application can be achieved.The current annual emission reductions remain at only 300 thousand tons,constrained by high costs,key technological bottlenecks,and insufficient policy support.We propose a phased development pathway characterized by demonstration-led scale promotion and cluster deployment.In the short term,efforts should focus on overcoming core technical barriers and integrating industrial chains.In the medium to long term,priorities should shift towards scaled application and institutional development.As scale expands,technological advances and systemic improvements,the cost of offshore CO2 storage is projected to decline to 50～150 RMB/tonCO2 by 2060,with an annual storage capacity of 200-300 million tons.This would contribute 15-20%of the cumulative carbon neutrality effort in China,significantly enhancing emission reduction capabilities while also promoting innovation in marine technology and climate governance.

Abstract:The CO2-assisted oxidation dehydrogenation of ethane to ethylene can achieve the low-carbon production of ethylene industry by reducing emissions from the source and the end products while realizing the resource utilization of CO2.Therefore,the research on the CO2-assisted oxidation dehydrogenation of ethane to ethylene not only holds significant theoretical significance but also boasts broad industrial application prospects.High-silica ZSM-5 zeolite are regarded as ideal carriers for ethane oxidative dehydrogenation reaction due to their tunable acidity,excellent stability,and unique pore structure.However,its Si/Al ratio significantly affects the distribution of acidic sites on the catalyst and the dispersion of metal species.The alkali treatment method can selectively remove Si or Al from the zeolite framework,thereby modifying its acidity.The effects of alkali treatment conditions on the structure,acidity and catalytic performance of high-silica ZSM-5 were investigated by modulating the acidity and alkalinity of zeolite through modulating the temperature of alkali-treated ZSM-5 carriers(40,60,80℃)and introducing zinc active sites on alkali-treated ZSM-5.The physical properties of the catalysts were characterized using methods including X-ray diffraction,N2 physisorption,field-emission scanning electron microscopy,high-angle annular dark-field scanning transmission electron microscopy,energy-dispersive X-ray spectroscopy,inductively coupled plasma optical emission spectrometry,NH3-temperature programmed desorption,ultraviolet-visible absorption spectroscopy,and X-ray photoelectron spectroscopy.Additionally,the catalytic performance of the catalysts for the oxidative dehydrogenation of ethane to ethylene were evaluated in a fixed-bed reactor.Finally,the structure-activity relationship of the ZnZ5-270-T catalyst was established.The results show that the alkali treatment preferentially removed the silicon species in the ZSM-5 skeleton and successfully introduced mesopores in ZSM-5 to form a multistage pore structure.This structure led to an increase in the zinc loading of the alkali-treated ZnZ5-270-T catalyst.Meanwhile,alkali treatment could change the type of ZnZ5-270-T zinc species from ZnO to ZnOH+with higher catalytic activity.The reaction network of the ZnZ5-270-T catalysts was revealed by analyzing the H2/C2H4 and CO/C2H4 mole ratios of the reaction products,indicating that indirect oxidative dehydrogenation was the main reaction pathway for all catalysts.It was also found that the loss of Zn species could be the main reason for catalyst deactivation.

Abstract:In response to the negative effects of greenhouse gas emissions,CO2 capture technologies are increasingly emphasized.Due to low energy consumption and operational simplicity,solid adsorption processes are regarded as promising candidates for next-generation technologies,which means that solid adsorbent has become the technical key of this process.Twelve-membered ring pore zeolites show great application potential in the field of gas separation due to their high mass transfer efficiency and high selectivity.Since the one-dimensional twelve-membered ring pores of ECR-1 and MOR zeolites have similar structural units,so by adjusting the raw material Si/Al ratio and super alkalinity,the transition between the two crystal phases and morphological changes can be achieved.The changes are verified by XRD,SEM and TEM methods.Slurry crystallization,a new preparation route,prepared a fibrous ECR-1 structure under the conditions of an over alkalinity of 0.33 and a Si/Al ratio of 7.On this basis,further increasing the Si/Al ratio can successfully synthesize MOR zeolite fiber rods with a diameter of 60-100 nm and a specific surface area of 425.58 m2/g.As the Si/Al ratio further increases,the sample becomes granular.In dynamic CO2 adsorption tests,the CO2 adsorption capacity of ECR-1 is observed to reach 3.98 mmol/g at 298 K and 1 bar.Furthermore,considering the actual working conditions of flue gas adsorption,adsorption tests are conducted using simulated flue gas containing water.It is found that compared with dry conditions,the CO2 adsorption capacity of fibrous zeolite decreased by 15%,and the MOR granules decreased by 4%～5%,indicating that the fibrous zeolite is more sensitive to the influence of water vapor.The inhibitory effect of H2O on CO2 adsorption is investigated by combining Si/Al ratio and morphology factors,indicating that the exposed 8-membered ring channels of the fibrous morphology may be the main factor for the decrease in adsorption capacity;the stable cyclic performance of ECR-1 is also tested.

Abstract:Accurate monitoring of carbon sinks and carbon emissions at the urban scale in China is of great significance for assessing the progress towards carbon neutrality.To precisely characterize carbon source-sink features at high resolution,an integrated model for urban net carbon emissions was developed and applied to the Yangtze River Delta(YRD)urban agglomeration in China as a case study.Firstly,the CASA model was employed to calculate the spatiotemporal distribution of monthly net primary productivity(NPP)for 2021-2022.The results reveal significant seasonal variations in NPP,with peak carbon sequestration during summer reaching 70-100 g/(m2·month)in major cities,while winter values generally remained below 15 g/(m2·month).Spatially,NPP exhibited a pattern of lower values in urban built-up areas and higher values in the vegetated southern regions.Additionally,an improved high-resolution spatial disaggregation method for carbon emissions,based on nighttime light data and population weighting,was proposed to downscale provincial-level emissions to a grid level.Results indicate that high carbon emission values are concentrated in urban centers,with per-grid emissions exceeding 5 000 t.Finally,the spatiotemporal distribution of net carbon emissions(NCE)was calculated at a 250 m resolution.The findings show that NCE in most cities exceeds 700 g/(m2·a),with only a few cities,such as Chizhou and Xuancheng in Anhui Province,acting as carbon sinks.The overall carbon sink proportion relative to total carbon emissions in the YRD region is 13.1%,reflecting a currently high level of net carbon emissions in this urban agglomeration.Significant disparities in NCE exist among cities,with Shanghai exhibiting markedly higher annual NCE compared to cities rich in vegetation resources,such as Hangzhou and Huzhou.The model demonstrates a strong capability to accurately capture the characteristics of urban carbon sinks and emissions,offering finer spatiotemporal resolution and more detailed spatial variability than existing data products.Owing to the comprehensive data coverage and methodological generalizability,the model can be applied to estimate NCE distributions in other urban areas across China,thereby aiding in understanding disparities in urban carbon neutrality levels and supporting decision-making for urban development and the construction of low-carbon cities.

Abstract:CO2 generated from the combustion of fossil fuels is the primary cause of global warming.Carbon capture and storage(CCS)is considered a key approach for reducing greenhouse gas emissions.Amine scrubbing,a mature technology currently being demonstrated at a commercial scale,is a suitable retrofit option for coal-fired power plants.However,the energy demand for solvent regeneration in chemical absorption-based CO2 capture significantly reduces power plant efficiency and power output.Therefore,new technologies with lower efficiency losses need to be developed.The promising Calcium Looping(CaL)technology has garnered significant attention for its potential to reduce efficiency losses and associated electricity costs.This technology is based on the reversible carbonation/calcination reaction of calcium-based sorbents under high-temperature conditions.This review summarizes the integration of CaL technology into coal-fired power plants and cement plants,evaluating ways to improve the performance of integrated systems.For the integration of CaL technology into coal-fired power plants,the review primarily focuses on three aspects:the heat source for the calciner in the CaL system,methods to reduce calciner energy consumption,and strategies for obtaining high-purity CO2.For the integration of CaL technology into cement plants,the emphasis is on summarizing the CO2 avoided costs in cement plants of varying scales,with and without CO2 capture systems.The findings indicate that when CaL technology is integrated into coal-fired power plants,the system efficiency penalty ranges from 2.6%to 7.9%,with CO2 avoided costs between €16～€53.1/t.For integration into cement plants,the CO2 avoided costs range from€17.1～€83.2/t.

Abstract:Direct air capture(DAC)technology is a crucial pathway to achieve carbon neutrality.Coupling with renewable energy is a necessary requirement for the deployment of DAC technology.With the rise of global commercial demonstration projects for adsorption-based DAC,the coupling technology of adsorption-based DAC and renewable energy has become a research hotspot.In terms of coupling system design,renewable energy powers the DAC system through methods such as electricity-driven and electricity-thermal combined energy supply.It also ensures stable operation by integrating electrical energy storage and thermal energy storage and can optimize the energy supply mix through multi-energy complementarity.The system operation modes include continuous operation and intermittent operation.The key equipment involves renewable energy power generation devices,adsorption reactors,energy storage equipment,etc.Additionally,their integration technology ensures the matching of energy transmission and conversion.The adaptability of different renewable energy sources(wind energy,solar energy,etc.)coupled with DAC needs to consider energy stability,accessibility and cost.In the evaluation and optimization of the coupling system,key indicators include CO2 capture efficiency,energy utilization efficiency and system stability.Modeling methods such as linear programming,mixed-logic dynamic,and Markov decision process are used to analyze system performance and explore the impact of factors such as the volatility of renewable energy as well as the performance degradation of adsorbents on the system.Moreover,the volatility of the atmospheric environment significantly affects the efficiency of adsorption-based DAC,and optimizing process parameters to adapt to changes in atmospheric conditions can improve its performance.The bottleneck in the current development of adsorption-based DAC technology is the high cost caused by high energy consumption and low net capture rate.The solution paths focus on optimizing the performance of adsorption materials and coupling with renewable energy.In the future,it is necessary to further optimize the coupling method to improve energy utilization efficiency.Carrying out technical-economic analysis studies and policy analyses on the coupled system technology is conducive to promoting the large-scale commercial deployment of adsorption-based DAC.

Abstract:Currently,while CCUS technologies have seen widespread research and demonstration efforts across numerous countries and regions,systematic studies on regional coordination and knowledge spillovers in their diffusion remain virtually absent.Moreover,a pronounced disconnect persists between the growth in patenting activity and the actual scale-up of deployment.Drawing on global CCUS patent data from IncoPat spanning 2000 to 2024,this paper innovatively integrates multiple spatial analytical methods,including the gravity model,Shapley decomposition,dynamic Logarithmic Mean Divisia Index(LMDI)decomposition,and Moran's I/LISA spatial autocorrelation to systematically characterize the evolutionary trajectories,regional contributions,and driving mechanisms of CCUS patent diffusion under a novel"space-contribution-driver"integrative framework.The results reveal that the global CCUS innovation hub has shifted eastward from the North Sea in Europe and the Gulf of Mexico in North America to East Asia and the broader Asia-Pacific region,demonstrating a catch-up pattern from west to east and from north to south.Regional spatial contributions exhibit a tripartite structure of"engine-counter-engine-hedging growth,"with the Asia-Pacific region serving as the dominant engine(55.7%),while Europe(4.8%)and North America(-28.6%)act as weak pull and strong counter-driving forces,respectively;South America and Africa display hedging growth patterns due to insufficient spatial coupling.Dynamic LMDI analysis reveals that global CCUS innovation has been primarily driven by economic scale and R&D efficiency,with a combined contribution of 142%;in contrast,the technology prioritization effect averages-25%,and input intensity contributes less than 5%,highlighting a structural imbalance characterized by"quantitative growth without qualitative enhancement."Spatial autocorrelation analysis indicates that,as of 2023,all CCUS segments except for transportation exhibit significantly positive global Moran's I values(I>0.13);however,"high-high"clusters comprise only 5%of observations,while over 90%of countries fall into"low-low"or statistically insignificant categories.This pattern reflects a Matthew effect,wherein technological diffusion is dominated by a few leading countries while the majority remain marginal followers,indicating that CCUS innovation diffusion remains at an early stage of"point-based concentration and surface-level insufficiency."To address these diffusion bottlenecks,it is imperative to establish cross-regional collaborative innovation networks,standardize cross-border permitting systems for CO2 transport and storage,enhance technological originality and quality orientation,and develop context-specific deployment strategies,thereby enabling CCUS to transition from scale-driven competition toward value-based synergy and equitable global diffusion.

Abstract:Amid the accelerating global response to climate change,carbon capture,utilization,and storage(CCUS)technologies have attracted increasing international attention due to their indispensable role in carbon-neutrality strategies.In recent years,governments across multiple countries have actively advanced CCUS demonstration projects through diverse policy instruments,including legislation,fiscal incentives,and technology roadmaps,in order to expedite commercialization.Against this backdrop,this study systematically reviews global CCUS-related policies from 1970 to 2024 using the International Energy Agency(IEA)policy database,categorizing them into 13 policy tools according to functional attributes,target groups,and implementation pathways,and developing a four-dimensional framework comprising economic incentives,national strategies,legislative and regulatory measures,and social demand.Using the top ten countries by announced project numbers as the sample,we identify 178 policy texts and 319 project cases for integrated qualitative and quantitative analysis.The results reveal three concurrent trends in the global CCUS policy landscape:Temporal acceleration,diversification of policy types,and cross-country heterogeneity.Specifically,economic incentives are most prevalent in the United States(19%),national strategies in the United Kingdom(16%),legislative and regulatory measures in the United States(53%),and social demand policies in Australia(15%).Furthermore,a panel fixed-effects regression further indicates a significant positive correlation between policies and the number of project announcements,with the dynamic effect of economic incentives being the most pronounced—highlighting the critical role of fiscal and subsidy instruments in facilitating project implementation.Guided by China's dual-carbon targets,policy design could draw on international experience by establishing diversified,CCUS-specific economic incentive mechanisms within the existing carbon market,while continuously strengthening regulatory frameworks and deepening international cooperation to achieve policy synergies and accelerate large-scale CCUS deployment.

Abstract:hydrogen energy,as a rich,clean and efficient energy carrier,is of great significance for building a new energy system and achieving the goal of"Carbon Peaking and Carbon Neutrality".The development of hydrogen storage technology is the key to promote the development of hydrogen energy industrialization.Carbon materials have become one of the most potential solid hydrogen storage carriers because of their excellent physical and chemical properties.The hydrogen storage mechanisms of carbon materials are mainly divided into physical adsorption,chemical adsorption,spillover mechanism and Kubas interaction.These four hydrogen storage mechanisms interact in the process of hydrogen storage.According to the physical and chemical properties of carbon materials such as specific surface area,pore structure and functional groups,the hydrogen storage characteristics show great differences.The hydrogen storage performance of carbon materials can be greatly improved by controlling the physical and chemical activation of carbon materials,metal and non-metal doping and multi-element co doping.Among them,the enhancement of metal doping is more significant due to its unique spillover mechanism and Kubas interaction.The hydrogen storage capacity can be increased about 6 times after metal doping at room temperature and atmospheric pressure.This paper systematically discussed the research progress of carbon materials in the field of hydrogen storage from the aspects of hydrogen storage mechanism,hydrogen storage characteristics of different types of carbon materials and modification of carbon materials,and summarized and prospected,aiming to provide theoretical basis and engineering guidance for the construction of efficient,low-cost,safe and reliable hydrogen storage system of carbon materials.

Abstract:In the context of the"dual carbon"goals,biomass energy,as a key component of renewable energy,is gradually becoming an important technological pathway to achieve carbon neutrality.Self-heating adsorption-enhanced biomass gasification(SSEG),as an emerging gasification technology,demonstrates significant advantages in improving hydrogen production and reducing carbon emissions through the synergistic effect of adsorption and gasification.Therefore,the self-heating adsorption-enhanced biomass gasification coupled with steam reforming(SSEG-SR)process was proposed.The process is modeled and simulated using Aspen Plus software,with thermodynamic modeling of the gasification and reforming processes conducted through a Gibbs reactor.Physical property estimations are performed using the Peng-Robinson cubic equation of state combined with the Boston-Mathias function.A comprehensive analysis of the SSEG-SR process chain is conducted from aspects of material flow,energy flow,economic viability,and environmental impact.The accuracy and reliability of the model construction are verified by comparing the simulation results with existing experimental and industrial operation data.Material flow analysis indicates that the SSEG-SR process consumes 7.63 tons of biomass feedstock to produce 1 ton of hydrogen,with a hydrogen conversion rate of 77.35%.Energy analysis shows that,of the 7 468.11 kW input energy to the system,279.99 kW is used for gasification energy supply,and 4362.52 kW is converted into hydrogen energy,with an overall system energy conversion efficiency of 58.42%.Economic analysis reveals that the total capital investment for the SSEG system is 9.2×108 Ұ,which is 1.2 times that of a coal-to-hydrogen plant of the same scale,with the final hydrogen cost being 18.2 Ұ/kg.Environmental analysis shows that the global warming potential(GWP)and acidification potential(AP)of the SSEG-SR process are 1 036.83 kg and 6.40 kg,respectively.The development and application of the SSEG-SR process provides theoretical support,playing a significant role in advancing the adoption of efficient,low-carbon biomass conversion technologies within the green hydrogen industry.It accelerates the transition to sustainable energy under the dual carbon goals.

Abstract:Green methanol,as a key carrier of sustainable energy and chemical feedstocks,demonstrates significant potential for achieving global carbon neutrality.Biomethanol,benefiting from the renewability of its feedstocks and low-cost advantages,is becoming a crucial low-carbon solution in the fields such as shipping and hydrogen storage and transportation.This review systematically summarizes the technological routes and industrialization progress for biomethanol production,evaluating the strengths and weaknesses of various routes,key unit operations and technological challenges,while offering perspectives on future developments.The primary technological routes include biomass gasification synthesis,biogas reforming,bio-CO2 hydrogenation,and pulp mill stripper off gas purification,among which the gasification route is the most representative due to its high maturity and scalability.Advances in gasification,tar removal,and methanol synthesis in the gasification route are highlighted,and the effect of wind-solar green hydrogen coupling on the carbon efficiency of biomethanol production is assessed.Additionally,the principles,technologies and the future potential of biogas direct conversion and dry distillation,which are still in experimental or pilot stages,are explored.The review provides a global overview of the biomethanol-based commercial projects,detailing process types,locations,capacities and development status in industrialization.Currently,there are over 80 biomethanol projects worldwide,primarily located in China,Europe and North America.These projects employ a variety of production techniques,with gasification being the dominant technology,alongside parallel development of biogas reforming,bio-CO2 hydrogenation and stripper off gas utilization technologies.Overall,the biomethanol industry is transforming from demonstration to large-scale production,with future progress dependent on breakthroughs in catalysts,energy integration and supply chain optimization.Biomethanol will continue to play a vital role in the green fuel sector and energy transition with its renewable and carbon neutrality advantages.

Abstract:Circulating fluidized bed combustion technology is a clean coal combustion technology that has witnessed rapid development in recent years.During rapid load changes in circulating fluidized bed units,substantial bed material remains within the furnace,containing unburned residual carbon and unreacted calcium-based desulfurizers.These substances not only affect the boiler's load change rate but also influence pollutant emissions.Therefore,how to effectively utilize the active reserves within the boiler plays a crucial role in improving the boiler's heat release rate and enhancing its load response speed.A 350 MW supercritical CFB boiler was selected as the research subject.Numerical simulations were conducted on the periodic fire suppression and startup process of the CFB boiler.Dynamic models for the active residual carbon inventory and active limestone inventory were established to analyze the gas-solid flow and active inventory during the periodic fire-down and restart process.The results indicate that after the secondary air fan and induced draft fan are shut down,the boiler enters a sealed state.In this state,the falling-back speed of the material in the furnace accelerates.The material in the return leg returns to the furnace under the influence of gravity.The average particle volume fraction in the dense phase zone reaches 0.45,while the particle volume fraction in the return chamber increases to 0.52 following material deposition.During the periodic fire suppression and startup process,the active residual carbon inventory under the stable operating condition stage 1 is 6353.11 kg,and the oxygen volume fraction is 5.35%.After starting the secondary air fan and coal feeder,the oxygen volume fraction drops significantly,while the active residual carbon inventory increases to 2868.76 kg.Regarding the periodic fire suppression and startup process,the desulfurization efficiency under the stable operating condition is 59.58%,and the active limestone inventory is 2702.29 kg.After starting the secondary air fan and coal feeder,the active limestone inventory rises to 1482.93 kg,and the desulfurization efficiency reaches 50.35%.

Abstract:Hydrogen energy,as a secondary energy source,possesses significant advantages such as abundant availability,environmental friendliness,wide-ranging applications,and high efficiency with low carbon emissions.It is widely regarded as an ideal clean energy.With the continuous growth of global energy demand and the escalating environmental challenges,the development and utilization of hydrogen energy have become increasingly important.Moreover,as a clean energy,hydrogen has immense development potential;it can be applied not only in transportation,industrial production,and household energy supply but also in various sectors such as the chemical and metallurgical industries.The development of hydrogen energy has become a key approach to addressing climate change,reducing greenhouse gas emissions,achieving energy transformation,and promoting sustainable development globally.Biomass,as a renewable energy source,is widely available in nature and offers advantages such as abundant resources,carbon neutrality,and environmental friendliness.It is one of the key sources for hydrogen production.Biomass-based hydrogen production technology aligns with the concept of resource recycling and can help reduce dependence on fossil fuels and lower environmental pollution.In this context,this paper reviews the development of biomass and its waste-based hydrogen production technologies,introduces several different biomass and waste hydrogen production methods,and summarizes the reaction mechanisms of these technologies.It also analyzes the main factors influencing the hydrogen production process and hydrogen storage technologies.Biomass hydrogen production technology is a viable and promising alternative.Research indicates that scholars both domestically and internationally have conducted extensive studies on the hydrogen production efficiency,catalysts,and reactors of various types of biomass,yet many technological bottlenecks remain.Furthermore,in response to the challenges of large-scale hydrogen energy applications,the development of diversified hydrogen storage integration technologies is expected to be a key trend for future advancements.

Abstract:The hydrothermal carbonization of microalgae has attracted much attention in recent years because it is a relatively mild process that can produce high-quality carbon materials such as N-doped carbon dots(CDs)without additional additives.However,the multicomponent coexistence of microalgae has led to complex hydrothermal reaction paths,and the interaction between components is unclear,which cannot effectively improve the yield and performance of CDs,becoming a core challenge for the controlled synthesis of microalgae-based CDs.In this study,glucose and glycine were selected as model compounds for carbohydrates and proteins to systematically investigate the effects of HTC parameters(temperature:190-250℃,time:2-8 h)on the synthesis of CDs.The results showed that the mass yields of glucose-based and glycine-based CDs prepared under the hydrothermal conditions in this study did not exceed 4.05 mg/g,whereas the interaction reaction between glucose and glycine could significantly enhance the mass yield of CDs,which could reach up to 29.85 mg/g.The fluorescence properties of glucose-based CDs were poor,with fluorescence quantum yields of less than 0.50%under all conditions,whereas the in situ N-doping of glycine-based CDs can reach 1.67%of fluorescence quantum yields.During the interaction reaction between glucose and glycine,not only retained hydrophilic groups such as—OH and—COOH on the surface of CDs,but also successfully doped with N in the carbon core,which made the glucose/glycine-based CDs with both high mass yield and fluorescence quantum yield.The effects of reaction temperature and time on the hydrothermal reaction of carbohydrate-protein model compounds were revealed,and it was found that the interaction between glucose and glycine could significantly improve the mass yield of CDs,and the N-containing compounds such as proteins could promote the N-doping of CDs to enhance the fluorescence performance.This study provides theoretical support for the characterization of the interaction reaction between the main components of microalgae and the design of high-performance N-doped CDs.