2024年12期目次

  • Design of efficient catalysts and research of catalytic mechanisms for CO2 hydrogenation to liquid products

    XIN Yue;ZENG Jie;Hefei National Laboratory for Physical Sciences at the Microscale,University of Science and Technology of China;School of Chemistry and Chemical Engineering,Anhui University of Technology;

    The conversion of CO_2 into high value-added chemicals with green hydrogen is of great significance in the resource utilization of CO_2,which effectively alleviates the ecological and environmental problems caused by excessive CO_2 emissions while improving energy efficiency. Recently,thermal-catalytic CO_2 hydrogenation have developed rapidly to produce a variety of renewable chemicals. Compared with gaseous product(such as CH_4 and CO),the resulting liquid products,such as methanol,gasoline,and aviation kerosene,are preferred due to their advantages of high energy density as well as easy storage and transportation,and have received extensive attention from both academia and industry. However,considering the chemical inertness of CO_2 molecules and the high energy barrier of C—C bond coupling,the activation of CO_2 and the selective conversion to liquid products are extremely challenging. Key issues such as low conversion per pass of CO_2,high selectivity of by-products such as CO,and easy deactivation of catalysts are still present. Herein,recent advancements of CO_2 hydrogenation to liquid products are systematically summarized. The mechanism of CO_2 hydrogenation to liquid products is introduced from the viewpoint of reaction pathway. Moreover,the design strategies of efficient catalysts are elaborated in detail. The effects of size,exposed facets,defect sites,alkali metal promoters,transition metal promoters,supports,surface groups,and hydrophilicity on the catalytic activity, selectivity, and stability are systematically summarized. In addition, the mechanisms of constructing and regulating the multifunctional active sites of catalysts in CO_2 hydrogenation to liquid products are also introduced from different scales. Future perspectives for the further development of CO_2 catalytic hydrogenation to liquid products are finally proposed.The fine design of catalysts,exploration of process conditions,optimization of reactors,and research on catalytic mechanism at the atomic and molecular levels will greatly promote the practical process of CO_2 hydrogenation to liquid products technology.

    2024 12 v.30;No.172 [Abstract][OnlineView][Download 2569K]

  • Recent advances in full-spectrum solar photothermocatalytic hydrogen production

    GUAN Jian;MA Rong;LI Donghui;YAN Xiaoqing;WEI Jinjia;SUN Jie;School of Chemical Engineering and Technology,Xi'an Jiaotong University;

    Solar hydrogen production is one of the key technological approaches for the vigorous development and utilization of renewable energy in China under the backdrop of the “carbon peak and neutrality” goals. Full-spectrum solar photothermolcatalytic hydrogen production,as a novel green hydrogen generation technology,leverages the synergistic advantages of photocatalysis and thermal catalysis to efficiently drive hydrogen production reactions under relatively mild conditions,achieving comprehensive utilization of full-spectrum solar energy. Currently,this technology significant development potential across various hydrogen production systems has demonstrated.However,there are significant differences in the photothermal catalytic mechanisms and hydrogen production efficiencies across various hydrogen generation systems,which urgently require further systematic organization and integration. Hence,recent advances in relevant research both domestically and internationally are reviewed in this paper. The solar photothermocatalytic hydrogen production technology of different hydrogen source systems(water systems, carbon-based fuel systems, and nitrogen-based raw material systems) is comprehensively reviewed and categorized. In addition, the mechanisms, performance advantages, and technical characteristics of photothermocatalysis are emphatically summarized. Specifically, photothermaocatalytic hydrogen production systems from water are categorized into two approaches: freshwater-based hydrogen production and seawater-based hydrogen production. The promotion of hydrogen production reactions and the enhancement of the full-spectrum solar utilization efficiency in photothermocatalytic water splitting are due to the elevation of the reaction temperature and the acceleration of charge carrier migration and separation,which are facilitated by the unique heterojunction structure or localized surface plasmon resonance effects of the catalyst. Photothermocatalytic hydrogen production systems from carbon-based fuels are subdivided into hydrogen production from methanol, methane, and other carbon-based fuels. The characteristics of the photothermocatalytic technology in this system are to reduce reaction activation energy,enhance the selective conversion of intermediate products, and prevent catalyst poisoning or deactivation. In addition, the photothermocatalytic systems for nitrogen-based raw materials include hydrogen production via ammonia decomposition and from urea wastewater. Water and urea in urea wastewater are simultaneously utilized for hydrogen production through photothermocatalytic technology, realizing a reaction pathway for dual hydrogen source hydrogen generation, while potentially solving the problem of wastewater treatment. Under the trend of energy transition in China, full-spectrum solar photothermocatalytic hydrogen production,characterized by its wide availability of hydrogen sources, mild reaction conditions, and high hydrogen production performance, is expected to become a significant technology for green hydrogen production.

    2024 12 v.30;No.172 [Abstract][OnlineView][Download 1827K]

  • Research progress and challenges of photovoltaic-driven electrolysis water splitting for hydrogen production

    CHEN Xin;REN Liping;CHEN Chunying;WANG Qi;LIU Keyan;FAN Jinpeng;WEI Jinjia;CHEN Jie;School of Chemical Engineering and Technology,Xi'an Jiaotong University;

    Photovoltaic driven hydrogen electrolysis,using photovoltaic power to produce hydrogen by electrolysis of water,is a promising green hydrogen production technology,and has significant advantages compared with other types of hydrogen production technology.This technology not only possesses notable advantages such as low energy consumption, pollution-free operation, and a simple structure,but it also converts unstable solar energy into stable hydrogen energy, offering reliable energy storage and peak-shaving capabilities for power systems. It is of great significance for establishing a sustainable energy system. In this paper,the research progress of photovoltaic driven water electrolysis technology is summarized, and optimization strategies for water electrolysis catalysts as well as the integration methods of photovoltaic-electrolysis systems are discussed. Firstly,given the background of energy crisis, the importance of photovoltaic driven hydrogen electrolysis in constructing the sustainable energy system is highlighted. Subsequently, the basic concepts of photovoltaic-electrolysis are introduced, by analyzing the principles and characteristics of different water electrolysis technologies, the key factors for enhancing electrolysis efficiency are revealed. Then, the design and optimization strategies of water electrolysis catalysts are explored, especially innovative approaches in electronic structure modulation, interface engineering, and surface engineering, and the existing strategies for improving the efficiency of hydrogen production by photovoltaic-electrolysis are summarized. Furthermore, the impact of coupling configurations on the efficiency of photovoltaic electrolysis systems is evaluated, and the technical difficulties associated with system integration and scaling-up are discussed. Finally,the challenges and future research directions of photovoltaicelectrolysis technology for hydrogen production are prospected. A detailed overview of the photovoltaic driven hydrogen electrolysis technology was provided,giving reference for the large-scale application and promotion of photovoltaic-electrolysis.

    2024 12 v.30;No.172 [Abstract][OnlineView][Download 2129K]

  • Photothermal synergistic catalytic water splitting for H2 production:Challenges and breakthroughs from the perspective of energy and mass transfer and conversion

    YAN Xueli;WANG Xinyi;ZENG Ziyu;ZHANG Shiyue;ZHANG Yongwang;ZHAO Xinyuan;ZHAO Shidong;WANG Biao;WANG Shujian;LIU Maochang;State Key Laboratory of Multiphase Flow for Power Engineering,Xi'an Jiaotong University;

    Solar photocatalytic water splitting for H2 production, with a simple and cost-effective reaction system, holds significant promise for addressing the current energy and environmental crises while achieving the “dual carbon” goals. However,traditional studies have primarily centered on the design of photocatalytic materials,lacking a systematic and cross-scale understanding of the energy and mass transfer and conversion processes at the reaction interface(involving gas, liquid, and solid phases). This oversight has resulted in low solar-to-H2 efficiency. This review elucidates the basic principle and processes of photocatalytic water splitting from the perspective of energy and mass flow,and delves into the bottlenecks,including non-steady-state light absorption and energy conversion,slow mass transfer processes(especially the nucleation,growth,and detachment of reaction interface bubbles,and the scarcity of water resources in extreme regions. In response to these challenges, this review elaborates on several breakthrough approaches. Firstly, it introduces a solar concentrating-photothermal coupling reaction system,which significantly enhances the wide-spectrum utilization of solar energy and the reaction potential and conversion efficiency of photogenerated carriers by utilizing concentrated photothermal technology to synergize light and heat. Secondly,this review elaborates on the theoretical and methodological foundations for constructing a new liquid-solid/gas-solid decoupled reaction system based on photothermal substrate, effectively overcoming the mass transfer limitations caused by bubble formation in traditional three-phase systems. Thirdly,it discusses the strategy for hydrogen production by coupling with atmospheric water harvesting and photocatalytic water splitting to address water scarcity issues,utilizing solar frequencydivision technology and gas-solid interface construction. Finally,from an engineering perspective,it emphasizes the significant impact and importance of system design and large-scale demonstration,and proposes future research directions in this field.

    2024 12 v.30;No.172 [Abstract][OnlineView][Download 2719K]

  • Study and application of six-component high-entropy two-dimensional materials in photothermal methanol reforming for hydrogen production

    HUANG Senyan;LIU Xin;LEI Runan;DU Kai;YU Chenyang;LI Yaguang;Research Center for Solar Driven Carbon Neutrality, Hebei University;

    To enhance the stability and efficiency of copper-based catalysts in photothermal methanol reforming for hydrogen production,this study proposes a catalyst design strategy based on high-entropy principles. A six-component high-entropy two-dimensional Cu_2Zn_1Al_(0.5)Ce_5Zr_(0.5)In_(0.5)O_x catalyst was successfully synthesized using a polyvinylpyrrolidone(PVP)-assisted freeze-drying method.Characterization techniques, including X-ray diffraction(XRD), scanning electron microscopy(SEM), transmission electron microscopy(TEM), and nitrogen adsorption-desorption analysis, confirmed the single-phase crystal structure and nanosheet morphology of the catalyst,along with its superior anti-sintering and anti-oxidation properties. In thermal catalytic reactions,the catalyst exhibited a hydrogen production rate of 1 887.94 mmol/（g·h） at 450 °C. When integrated with a novel photothermal conversion device,the catalyst demonstrated remarkable photothermal catalytic activity under a solar intensity of 2 kW/m2,achieving a methanol steam reforming hydrogen production rate of 1 402.12 mmol/（g·h） while maintaining stability over 72 hours,indicating exceptional long-term durability.Further experiments revealed that the high performance of this catalyst is primarily attributed to the thermodynamic stability and unique porous structure derived from its high-entropy characteristics. These features significantly increased the number of catalytic active sites and enhanced resistance to high-temperature conditions. Compared to traditional catalysts,the six-component highentropy Cu_2Zn_1Al_(0.5)Ce_5Zr_(0.5)In_(0.5)O_x exhibited significantly improved catalytic performance and stability in photothermal methanol reforming for hydrogen production, addressing the sintering challenges caused by temperature fluctuations in outdoor photothermal systems. This study not only provides a novel and efficient catalyst design strategy for the photothermal catalysis field but also advances the practical application of high-entropy materials under complex reaction conditions. By integrating high-entropy materials with photothermal catalytic technology,this work offers theoretical support and practical solutions for the sustainable and efficient production of hydrogen energy,showcasing the broad industrial application potential of this catalyst in hydrogen production.

    2024 12 v.30;No.172 [Abstract][OnlineView][Download 1748K]

  • Efficient conversion and carbon deposition inhibit strategy of photothermal-driven methane reforming on Ni@SrTiO3 catalyst

    MA Xu;YANG Weiwei;School of Energy and Power Engineering,Xi'an Jiaotong University;

    This study delves into the exploration of efficient reaction characteristics of methane and carbon dioxide in a photothermal heterogeneous catalyst system,aiming to provide a more promising catalytic solution for methane dry reforming.To achieve this objective,three catalysts:Ni@CaAl_xO_y,Ni@SrTiO_3,and Ni@Sr_(0.5)Ba_(0.5)TiO_3 were selected and comprehensively evaluated for their performance within a broad temperature range of 400—800℃.The experimental results demonstrated that the Ni@SrTiO_3 catalyst exhibited the highest stability and catalytic activity,particularly at 800℃,where its methane conversion peaked at 89.12%,significantly outperforming the other two catalysts.This performance not only underscores the potential application of Ni@SrTiO_3 in methane dry reforming but also highlights the significant advantages of photothermal drive technology in enhancing catalytic performance.Furthermore,this study employed advanced characterization techniques,including hydrogen temperature-programmed reduction (H_2-TPR),carbon dioxide temperature-programmed desorption (CO_2-TPD),and electron paramagnetic resonance (EPR),to delve into the underlying mechanisms of Ni@SrTiO_3’s superior performance.Through these characterization techniques,it was found that Ni@SrTiO_3’s exceptional performance is primarily attributed to its unique surface defect structure, abundant alkaline centers, and high concentrations of oxygen vacancies. These characteristics not only facilitate the adsorption and activation of reactants but also optimize the oxygen migration mechanism, thereby enhancing catalytic efficiency. Additionally, Ni@SrTiO_3 demonstrated robust anti-coking performance, benefiting from its optimized ternary catalytic interface, which effectively inhibits side reactions in methane dry reforming, further ensuring the stability and durability of the catalyst. These findings not only provide a more promising catalytic solution for methane dry reforming but also offer important theoretical guidance and practical basis for the design and optimization of catalysts. Future research will further optimize the composition and structure of the Ni@SrTiO_3 catalyst to achieve more efficient and sustainable methane conversion and hydrogen production processes.

    2024 12 v.30;No.172 [Abstract][OnlineView][Download 1831K]

  • Simulation analysis of an energy storage system for solar-driven chemical looping reforming of methane to produce hydrogen and methanol

    WANG Yanjuan;LONG Yunfei;XIN Yu;JIANG Qiongqiong;XU Chao;QU Wanjun;HONG Hui;School of Energy,Power and Mechanical Engineering,North China Electric Power University;Institute of Engineering Thermophysics,Chinese Academy of Sciences;Guangdong Provincial Key Laboratory of Distributed Energy Systems,School of Chemical Engineering and Energy Technology,Dongguan University of Technology;

    To achieve safe storage and transportation of hydrogen energy,converting hydrogen gas into liquid methanol has become an important method for hydrogen storage. Hydrogen and carbon monoxide(CO) are used to produce methanol via the Fischer-Tropsch synthesis,which is widely applied due to its excellent performance. Traditional methods of producing hydrogen and CO mainly involve methane steam reforming and dry reforming of methane. However,these methods require high temperatures （≥850 ℃） and have high energy consumption,often relying on the combustion of methane to provide heat for the reaction. This paper proposes a solar-driven chemical looping reforming system for hydrogen production and methanol synthesis, using nickel oxide as the oxygen carrier. The reaction temperature can be reduced to 600 ℃, and the system is powered by solar thermal energy, avoiding methane combustion,reducing energy consumption,and lowering environmental impact. Additionally,following the principle of “temperature matching and cascading utilization”, the high-temperature flue gas and gas steam generated by methane chemical looping reforming are coupled in a combined cycle for power generation. Energy,efficiency,and sensitivity analysis results show that when the fuel reactor and air reactor temperatures are 600 °C and 1 200 °C,respectively,the molar ratio of nickel oxide to methane is 0.8,and the molar ratio of water to methane is 1.9,the system achieves an energy utilization efficiency of 62.82%,an efficiency of 64.75%,and a methanol yield of 69.73%.Under these conditions,the methane conversion rate is 80.58%,which is 250 ℃ lower than traditional methane reforming methods,while significantly improving the methane conversion rate.

    2024 12 v.30;No.172 [Abstract][OnlineView][Download 1606K]

  • Techno-economic and environmental assessment of a novel hydrogen production system based on complementary coal and biomass gasification technology

    ZHANG Zhong;LI Sheng;School of Mechanical Engineering,Beijing Institute of Technology;

    Gasification technology is one of the core processes in coal-based hydrogen production systems,and in this research,the copyrolysis behavior of coal and biomass was investigated through a vertical tube furnace,and a novel hydrogen production system based on complementary gasification technology of coal and biomass was proposed. The synergistic effect of coal and biomass co-pyrolysis promotes pyrolysis gas generation and improves the gasification efficiency. Biomass with lower combustion energy grade supplies heat for the gasification reaction, which improves the grade matching between gasification and combustion reactions. In addition, the use of carbon-neutral biomass fuels for complementary gasification technologies can significantly reduce carbon emissions. In this research,the novel and reference systems were simulated using Aspen Plus software to evaluate the performance of the novel and reference systems in terms of thermodynamics,carbon emission and economic feasibility. The results showed that the synergistic effect of the pyrolysis process was most significant at a biomass blending ratio of 0.25,and the energy and yield efficiencies of the novel system were higher than that of the reference system at 76.82% and 64.56%,respectively. The carbon emission of the novel system is 1.12 t/h,which can significantly reduce the carbon emission relative to the conventional coal-water slurry hydrogen generation system. The DPP, NPV and cost of hydrogen production of the novel system during the whole life cycle are 3.41 years,269 535.58×103 $ and 1.37 $/kg,respectively,which have good economic benefits and application prospects.

    2024 12 v.30;No.172 [Abstract][OnlineView][Download 1785K]

  • Research progress about liquid organic hydrogen carriers technology

    LU Shuhan;GONG Xiang;WANG Bin;YANG Fusheng;FANG Tao;New Energy System Engineering and Equipment Shaanxi Provincial University Engineering Research Center,Key Laboratory of Energy and Chemical Process Enhancement in Shaanxi Province,College of Chemical Engineering and Technology,Xi'an Jiaotong University;Hydrotransformer Co.,Ltd.;Shaanxi Province Normal Temperature and Pressure Liquid Hydrogen Storage Technology Innovation Consortium;

    In the context of the current global energy structure transformation and carbon peaking and carbon neutrality goals,effective energy storage technology has become critical. Particularly for clean energy sources such as solar and wind power, the application of energy storage technology is the core for their efficient utilization and stable supply. Hydrogen,as a kind of energy carrier with high energy density and clean,renewable characteristics,has received extensive attention. However,issues such as the poor stability of hydrogen,its tendency to leak,and the risk of combustion and explosion have limited its widespread application in energy storage and transportation.To address these challenges,researchers have proposed various hydrogen storage technologies,including high-pressure gaseous hydrogen storage, liquid hydrogen storage, and solid-state hydrogen storage, among others. Among these, Liquid Organic Hydrogen Carriers(LOHC) technology has garnered particular interest due to its ability to store hydrogen long-term,on a large scale,and stably,while effectively avoiding hydrogen diffusion losses. Additionally,LOHC technology offers advantages such as mild storage conditions and the utilization of existing infrastructure for transportation,endowing it with significant potential in the field of hydrogen energy storage and transportation. Based on this, this paper systematically reviews LOHC technology from three dimensions: the development of liquid organic hydrogen carriers,the design of hydrogenation and dehydrogenation catalysts,and industrialization research,elaborating on the latest research trends in this technology. Firstly,regarding the research progress of liquid organic hydrogen carriers,this paper introduces in detail the physical and chemical properties of common liquid organic hydrogen carriers, the requirements of hydrogenation and dehydrogenation reactions,as well as their advantages and limitations,and discusses newly proposed hydrogen storage systems in recent years, including amide and ester hydrogen storage systems. Secondly, concerning the research progress in hydrogenation and dehydrogenation catalysts,this paper explores new research directions in this field. Researchers have proposed more diversified new ideas for the design and development of catalysts for hydrogenation reactions using crude hydrogen,wet hydrogen,and other hydrogen sources;suggestions for optimizing the use of liquid organic hydrogen carriers and implementing reaction cascades have been made to address the stringent conditions of dehydrogenation reactions and the slow rate of hydrogen release. Furthermore,this paper reviews the research on industrialization, including economic analysis, reactor design, and process optimization. Economic analysis indicates that LOHC technology has significant economic advantages over the currently most commonly used high-pressure gaseous hydrogen storage for high hydrogen demand and long-distance transportation. In terms of process optimization, researchers have proposed methods such as microwave radiation and mixed liquid organic hydrogen carriers to enhance the heat and mass transfer effects in LOHC hydrogenation and dehydrogenation reactions. Finally, this paper will summarize the progress in each research direction and outlook on the future development and application of LOHC technology, with the aim of promoting the advancement of liquid organic hydrogen carriers technology through comprehensive discussion.

    2024 12 v.30;No.172 [Abstract][OnlineView][Download 1722K]

  • Comparative study of machine learning regression algorithms for predicting thermal energy storage performance of metal hydrides with high hydrogen density

    YANG Yikun;WU Zhen;LIU Honghao;ZHANG Zaoxiao;School of Chemical Engineering and Technology,Xi'an Jiaotong University;State Key Laboratory of Green Hydrogen and Electricity;

    Metal hydride thermal/hydrogen energy storage material is considered ideal candidate due to high energy density,wide working temperature range and lack of corrosive pollutants. Multi-component metal hydride alloys can be formed by doping with different elements to obtain various target properties. However, conventional material development method relies on experimental synthesis,having the disadvantages of time-consuming and costly. Data-driven machine learning prediction model is capable of addressing this problem. By comparing varieties of regression algorithms such as least squares regression,least absolute shrinkage and selection operator regression,ridge regression,elastic net regression,supporting vector regression,and random forest regression,the relationship between the microscopic properties of metal hydride materials and their macroscopic formation energy are established. Results show that random forest regression have the best prediction performance,with lowest relative errors on both the training and test sets of 3.078 and 8.201 1,high R-squared values,and great generalization and regression abilities. SHAP analysis reveals extreme and mean value of ground state atom of metal hydride exhibit the greatest SHAP value of 5.56 and 1.26,suggesting their significant influence on the formation energy.Analysis for the prediction value of Mg-base,Ca-base,AB type,AB2 type,and AB5 type metal hydrides shows the highest relative error below 9%,further proving the accuracy and universality of the model for all types of metal hydride. This model can be used to predict the formation enthalpy of unknown datasets.

    2024 12 v.30;No.172 [Abstract][OnlineView][Download 4127K]

  • Electricity-hydrogen coupled integrated energy system: Resilience quantification and multi-objective optimization

    HUANG Jingzhi;XIAO Ning;HUANG Xianan;LIN Changzhui;HU Zhenda;LIU Lin;WU Nianyuan;ZI Zhengyu;LIN Jian;XIE Shan;JING Rui;ZHAO Yingru;College of Energy,Xiamen University;State Power Investment Corporation;State Grid Fujian Economic Research Institute;Shenzhen Research Institute of Xiamen University;

    In recent years,interest in electricity-hydrogen coupled integrated energy system is growing to enhance system resilience. This paper proposes a quantitative evaluation method of energy system resilience with high time resolution(hourly level),and constructs a bottom-up multi-objective optimization model to plan the park-level electricity-hydrogen coupled integrated energy system,to cope with the triple dilemma of the energy system(economic-environmental-resilience),and to assess the benefits of the application of electricityhydrogen coupled technology to integrated energy system. In this paper,the methods and models proposed are applied to the energy system of an industrial park along the southeast coast of China as a case study,and multi-objective optimization is carried out under four carbon emission limitation scenarios according to the disturbance pattern of extreme events on the energy system in order to determine the optimal solution under each scenario. The results of the case studies indicate that,due to the current high cost of electricity-hydrogen coupled technology applications,electric-hydrogen coupled technology applications are of greater value only when both environmental and resilience of the energy system are required. With the strengthening of carbon emission constraints,the net present value cost of the economics objective function increases from 4.48×1010 RMB in the global scenario to 4.74×1010 RMB in the strongest carbon emission limitation scenario,which is an increase of 5.80%. The resilience indicator,on the other hand,decreases by 21% from 5 061.62 MWh to4 184.01 MWh,and the electricity-hydrogen coupling significantly improves the environmental and resilience of the system. The optimal solution shows that hydrogen storage is not only an effective solution for long-term energy storage across seasons, but its unique advantages in short-term energy storage are also worthy of attention. Finally,comparing the new method of quantitative evaluation of resilience proposed in this paper with the representative previous method,it can improve the net present value of the optimized solution by 0.9%,the minimum level of system energy supply by 5.19%,and the system resilience by 12.57%.

    2024 12 v.30;No.172 [Abstract][OnlineView][Download 1687K]

  • Integration and evaluation of a natural gas-ammonia complementary power generation system based on ammonia-driven calcium looping for CO2 capture

    ZHENG Yawen;ZENG Xuelan;LIU Jianhui;WANG Junyao;HE Song;YANG Guang;FAN Junming;Collaborative Innovation Institute of Carbon Neutrality and Green Development,Guangdong University of Technology;Shenzhen Gas Co.,Ltd.;School of Material and Energy,Guangdong University of Technology;

    Natural gas power plants will play an important role in scenarios with high renewable energy input due to their clean,efficient and excellent peak-shaving capacity. Although natural gas power plants have lower carbon emission intensity compared to coal-fired power plants,they remain a major source of global CO_2 emissions. CO_2 capture,utilization,and storage(CCUS) technologies are essential for achieving carbon neutrality, with post-combustion calcium looping technology drawing significant attention due to the widespread availability and low cost of its absorbents. Traditional oxy-fuel calcium looping capture technology uses pure oxygen and fossil fuels to supply heat for the calcination process and recovers the constant-temperature heat from the carbonation reaction by directly heating steam,resulting in high energy penalties. A novel ammonia-driven calcium looping CO_2 capture system for natural gas-ammonia complementary power generation has been proposed,in which ammonia replaces fossil fuels as a zero-carbon fuel. This new system avoids the additional carbon capture demand caused by fossil energy heating and utilizes ammonia pyrolysis to recover medium-temperature heat released from the carbonation reaction, avoiding large temperature difference heat exchange losses when directly heating steam. The results show that,compared to traditional oxy-fuel calcium looping systems,the efficiency penalty of the new system drops from 9.4% to 0.6%, and the CO_2 avoided energy consumption decreases from 4.7 to -8.1 MJ/kg, significantly improving its thermodynamic performance. At the same time,the carbon emission intensity of the new system is significantly reduced compared to the oxy-fuel calcium looping system,reaching 18.6 kg/MWh. An analysis of the effect of gas turbine inlet temperature and pressure at ammonia side on the new system's performance shows that the new system performs well across a wide range of operating parameters.

    2024 12 v.30;No.172 [Abstract][OnlineView][Download 1611K]

  • Distributed integrated energy system integration and optimization for full-spectrum solar and hydrogen energy utilization

    ZHAI Yukai;WANG Jiongchao;WU Hanyi;WANG Ruilin;ZHAO Chuanwen;School of Energy and Mechanical Engineering,Nanjing Normal University;School of Architecture and Engineering,Zhejiang University;

    Existing hybrid energy systems using solar and hydrogen often face challenges such as low energy utilization efficiency and mismatches between energy supply and demand. To address these issues,a distributed integrated energy architecture for full-spectrum solar and hydrogen utilization is proposed. Considering the optimal output of solar energy,a spectral splitting window of 700–1 100 nm is established. Targeting an industrial park in Nanjing,Jiangsu Province,as the energy supply object,the study analyzed the park's hourly demand for electricity,cooling,heating,and domestic hot water over the course of a year. A system was designed,and a full-condition dynamic digital model was developed in Matlab. Simulation results showed that, compared to a reference system, the new system improved annual energy utilization efficiency by 10.43% and reduced greenhouse gas emissions by 655 660 kg,demonstrating its superior energy efficiency and environmental friendliness. The effects of solar concentrator area and thermal storage capacity on system performance were explored individually. After balancing system performance and economic costs, capacity optimization for the new system was performed,identifying an optimal configuration with a solar concentrator area of 6 000 m~2 and a thermal storage capacity Nstore of 0.9. Post-optimization, the system's energy efficiency reached 29.03%, an increase of 3.56% from the initial configuration. This distributed integrated energy system,which synergistically utilizes full-spectrum solar and hydrogen energy,not only enhances energy utilization efficiency but also significantly reduces greenhouse gas emissions, offering a novel approach to achieving sustainable development goals.

    2024 12 v.30;No.172 [Abstract][OnlineView][Download 2202K]

  • System assessment of integrating calcium looping and chemical looping hydrogen generation processes for cement plants decarbonization

    HE Song;WANG Dan;ZHENG Yawen;GAO Lifan;WANG Junyao;YANG Zhi;ZENG Xuelan;Collaborative Innovation Institute of Carbon Neutrality and Green Development,Guangdong University of Technology;State Power Investment Group Hydrogen Energy Technology Development Co.,Ltd.;China Shenzhen Gas Corporation Ltd.;School of Material and Energy,Guangdong University of Technology;

    Zero-carbon fuel substitution and CO_2 capture will play a crucial role in the decarbonization of cement plants. This paper proposes an integration scheme that combines the calcium looping process with the chemical looping hydrogen generation process(Ca LCLHG). The CaL-CLHG scheme offers the advantage of recovering waste heat from the cement production process for hydrogen generation. Besides, the CaL-CLHG scheme avoids the power consumption associated with air separation in the traditional calcium looping process(CaL-Oxy). Results indicate that the specific primary energy consumption for CO_2 avoided can be achieved at 2.68 GJ/t in the CaL-CLHG scheme. This represents a reduction of 33.5% compared to the CaL-Oxy scheme. Economic analysis indicates that the cost of CO_2 avoided can be reduced from 56.6 $/t in the CaL-Oxy scheme to the range of 34.2-41.6 $/t in the CaL-CLHG scheme. In conclusion,adopting the CaL-CLHG process for the decarbonization of existing cement plants presents a techno-economically feasible option.

    2024 12 v.30;No.172 [Abstract][OnlineView][Download 1581K]



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