Abstract:A three-dimensional numerical model integrating electrochemical processes with gas-liquid two-phase Euler-Euler turbulent flow is developed,considering the collision forces caused by gas-liquid two-phase distribution at the microscale within an industrial filter-press alkaline electrolyzer.The individual and coupled effects of electrolyte flow rate,temperature,and concentration on the performance of the electrolyzer are systematically investigated.The results indicate that bubble accumulation along the flow channel reduces current density and causes uneven electrode utilization.Increasing the electrolyte flow rate to 0.25-0.30 m/s enhances turbulence,facilitating bubble detachment and improving current density;however,excessively high flow rates significantly increase the risk of equipment corrosion.At temperatures between 60 and 70℃,the positive effects on electrolyte conductivity and ion transport significantly enhance current density,which peaks within this range.Conversely,temperatures above 70℃induce performance degradation due to bubble accumulation.At a KOH concentration of 6-7 mol/L,an optimal balance between electrolyte conductivity and ion transport efficiency is achieved,yielding the most uniform current density distribution.Multi-parameter coupling analysis further reveals that a high flow rate can effectively suppress the negative effects caused by high temperature or high concentration,significantly improving current density.In contrast,the combination of high temperature,high concentration,and low flow rate leads to a sharp performance deterioration due to the synergistic effects of bubble curtain and ion blockage.These findings elucidate how gas-phase distribution and individual and synergistic effects of operating parameters influence electrolyzer performance,providing theoretical guidance for optimizing the design and operation of filter-press alkaline electrolyzers.

Abstract:To scientifically evaluate the true environmental performance of China's hydrogen fuel cell industry under the"dual carbon"goals and overcome the limitations of existing research,which heavily relies on foreign databases and lacks consideration of spatial heterogeneity,this study established a localized carbon emission assessment model integrating Geographic Information System(GIS)and Life Cycle Assessment(LCA).The carbon emissions in five stages including raw material production,transportation,assembly,usage and recycling after scrapping was calculated.The carbon footprints of PEMFC under four different hydrogen production pathways which were coal gasification,methane reforming,purification of industrial by-products and green electricity-water electrolysis were compared.The calculation results based on a functional unit of 80 kW rated power showed that the base carbon emissions excluding usage phase are 1 198.57 kg CO2-eq,with the raw material production stage contributing 66.26%.The production of platinum was the largest emission source in this stage,accounting for 30.73%of the base carbon emissions.When considering the indirect carbon emissions from different hydrogen sources,the usage phase becomes the dominant link in the total carbon emissions.It was the highest when the hydrogen for fuel cells was produced through coal gasification,reaching 28 698 kg CO2-eq,followed by that from CH4 reforming of 14 948 kg CO2-eq.When hydrogen is sourced from green electricity-water electrolysis,the carbon emissions was the lowest of 4 848 kg CO2-eq,making the total carbon emissions under this path only 16.9%of those from coal gasification hydrogen production.

Abstract:The two-step metal oxide thermochemical cycle hydrogen production technology is a clean hydrogen production method that utilizes a high-temperature heat source to drive the oxidation-reduction reaction of metal oxides to achieve water splitting.This technology involves two steps:first,at high temperatures(1 000-1 500℃),metal oxides undergo thermal splitting in an inert atmosphere to release oxygen and form low-valent oxides.Then,at moderate to low temperatures(500-800℃),the low-valent oxides react with water to produce hydrogen and revert to their initial form.This two-step cycle enables efficient,high-purity hydrogen production.Compared to direct thermal hydrolysis,its core advantages lie in its strong temperature adaptability,enabling deep integration with zero-carbon heat sources such as solar and nuclear energy;hydrogen and oxygen are produced in separate steps,allowing hydrogen to achieve high purity without separation;and metal oxides,as oxygen carriers,can be reused,providing an important pathway for large-scale clean hydrogen production.Based on this,a systematic review of the research progress of this technology is presented,with detailed introductions to three representative reaction systems:single metal oxides,composite metal oxides,and synergistic reduction with the introduction of a reducing medium.The selection and structural design of metal oxide materials,reaction temperature and atmosphere control,reaction kinetics and mass transfer process optimization,catalyst and additive selection,as well as system design and process integration.Strategies to enhance hydrogen production efficiency and stability under each reaction system are summarized,and challenges such as high-temperature sintering,slow reaction kinetics,and high system costs are identified as key obstacles to further technological development.Future research could focus on developing new high-efficiency oxygen carriers,regulating oxygen vacancy concentration to further reduce reaction temperature;innovative reactor structure design to enhance efficiency;and constructing multi-heat source coupled intelligent control systems,among other areas,to advance the two-step metal oxide thermochemical cycle hydrogen production technology toward large-scale,low-cost development.As the"dual carbon"goals continue to advance,this technology is expected to provide an effective and feasible pathway for energy structure transformation and green,low-carbon development.

Abstract:Coal gangue,a solid waste generated during coal mining and washing processes,poses significant environmental risks when left to accumulate naturally.Prolonged accumulation not only occupies land and causes soil erosion but also increases hazards like spontaneous combustion and explosions.Moreover,its heavy metal content contributes to soil and groundwater contamination.Statistics show China's annual coal gangue production exceeds 700 million tons,with cumulative stockpiles surpassing 6 billion tons.Consequently,effective management and utilization of coal gangue have become critical challenges for the coal industry.Current applications primarily include road construction using waste rock,mine backfilling,and producing low-performance building materials like bricks and tiles.These rough applications fail to make full use of the rich chemical components and rare elements of coal gangue,such as SiO2,Al2O3,Fe2O3,K2O,MgO,CaO,Na2O,Ni,B,Be,Ti and Ga.With China's sustainable development strategy,the industry is shifting toward green,high-value utilization.Innovative approaches include:extracting alumina and silica gel through acid leaching;developing geopolymer materials with 1.5 times the strength of traditional cement via alkali-activated processes;synthesizing zeolite molecular sieves for wastewater treatment and gas adsorption using thermal activation technology;and optimizing formulations to produce high-performance ceramics or microbial-modified soil conditioners that regulate pH levels and supplement trace elements.From the perspective of coal gangue mineral composition,this study systematically discusses the current status of high-value utilization of coal gangue as raw material,including chemical product extraction,synthetic geopolymer production,and preparation of ceramics,zeolite molecular sieves,and soil amendments.It analyzes the main challenges in coal gangue application and the development trends of multi-component cascade utilization models,aiming to provide insights and references for related research on coal gangue and the high-value utilization of solid waste.

Abstract:The medium-and low-temperature phase change thermal storage systems can effectively store solar energy,low-grade industrial waste heat,and other thermal energy.They help alleviate the mismatch between energy supply and demand,promoting the integration of renewable energy and the comprehensive development of distributed energy systems.However,phase change packed bed thermal storage systems face the issue of low energy utilization efficiency when utilizing medium-and low-temperature heat sources,which has become a critical bottleneck limiting the improvement of their overall performance.This paper begins by introducing the structural composition,working principles,and internal heat transfer mechanisms of phase change packed bed thermal storage systems.It analyzes the heat transfer characteristics during the charging and discharging processes.Next,the performance evaluation methods and key influencing factors are discussed in detail,including operational parameters,material parameters,and structural parameters.The impact of these parameters on the thermal performance of packed bed thermal storage systems is further examined.Special attention is given to the effects of tank structure and size,filler structure and size,distributor design,and filling methods on the flow and heat transfer characteristics within the packed bed.Strategies for enhancing system performance through multi-parameter optimization are summarized,providing theoretical and experimental support for the optimized design and efficient operation of the packed bed thermal storage systems.Finally,the applications of phase change packed bed thermal storage systems in medium-and low-temperature fields,such as solar thermal utilization,industrial waste heat recovery,and power load leveling,are outlined.The future development prospects and challenges of this technology are also discussed.

Abstract:The challenges of inadequate combustion stability and excessive NO*emissions remain critical bottlenecks for the utilization of ammonia as a zero-carbon fuel.Gliding arc plasma technology is employed to enhance the combustion performance of methane/ammonia premixed mixtures.The stability and emission characteristics of methane/ammonia/air premixed swirling flames are examined under various equivalence ratios(Φ)and ammonia contents(xNH,).Increasing ammonia contents raises the flame height and reduces flame stability,whereas the application of gliding arc plasma significantly improves stability.With xNH,ranging from 0 to 1.0,the use of gliding arc plasma extends the lean blow-off limit to 0.46-0.79(an increase of approximately 10.2％-40.3％)and the rich blow-off limit to 1.92-2.31(an increase of approximately 28％-32％).Spectral diagnostic indicate that the emission intensities of H*,OH*and NH*active species increase with ammonia content,promoting combustion.The NH2* species play a major role in reducing NOx emissions during combustion.At Φ=1.1 and low ammonia contents(xNH,＜0.6),gliding arc plasma slight increases NO emissions,reaching a peak at xNH3=0.4(an increase of about 9％)due to the elevated flame temperature and enhanced thermal NOx formation.As xNH3 increases further,gliding arc plasma strengthens the NH2*-induced NO reaction pathways,achieving a maximum NO reduction of 15.5％.Reaction pathway analysis shows that ammonia is first converted to NH*,which subsequently participates in two competing processes:oxidation through the HNO intermediate to produce NO,or direct NO reduction to form N2 and NNH.The negative sensitivity coefficient of NO confirms that NH*plays dominant role in NO reduction.Gliding arc plasma effectively enhances the stability of methane/ammonia premixed flames,extends the lean and rich flammability limits,and reduces NOx emissions,providing a promising route for clean and efficient ammonia combustion.

Abstract:Parabolic-trough solar thermal power,characterized by its green,low-carbon,and grid-friendly attributes,is a highly promising renewable energy generation technology.However,existing research lacks in-depth analysis of the dynamic response characteristics of the heat collection field and the steam generation system in the parabolic-trough solar thermal power plant.To address this gap,this study focuses on China's operational 50 MW parabolic-trough solar thermal power plant in Delingha.A dynamic simulation model of the plant's collector field and steam generation system was established on the domestic STAR-90 software platform and validated against the plant's actual operational data.Subsequently,the dynamic responses under step perturbations of two critical parameters-Direct Normal Irradiance(DNI)and heat transfer oil flow rate-were investigated.Key findings reveal that when DNI fluctuates by±50 W/m2 around its design parameter of 900 W/m2,the outlet temperature of the heat collection field exhibits a response time of 4 minutes and fluctuates within±5.6℃;the steam generation system demonstrates a response time of 12.5 minutes for both main and reheat steam,with temperatures fluctuating by±5.6 and±4.0 ℃,respectively,and pressures varying by±0.46 MPa(main steam)and±0.07 MPa(reheat steam).When the heat transfer oil flow rate of the steam generation system fluctuates by±10％from its design value,the main and reheat steam exhibit response times of 8 minutes(for a step increase)or 9 minutes(for a step decrease),with temperature fluctuations of±0.4 and±2.0 ℃,respectively,and pressure variations of±0.4 and±0.07 MPa.

Abstract:CaCO3/CaO is rich in resources,low in price,and has large energy storage/release capacity.It is a potential thermochemical energy storage material,but its energy storage capacity decays rapidly after multiple cycles.Based on the separation and purification treatment of egg shell waste,three organic acids(including acetic acid,citric acid and gluconic acid)and purified egg shells were used to prepare the corresponding calcium acetate(DCA),calcium citrate(DCCi)and calcium gluconate(DCG).A detailed study was conducted on its energy storage and heat release efficiency as well as the evolution of its structural and morphological characteristics during multiple cycles.It was found that DCG-CaO has the highest energy storage capacity and heat release efficiency,but its cycle stability is poor.In order to improve the sintering resistance and cyclic exothermic performance of DCG-CaO,the sol-gel combustion synthesis method(SGCS)was used to dope Al2O3 with different mass ratios.Research on its cyclic energy release showed that the optimized DCG-CaO/Al2O3 mass ratio was 9∶1,the cyclic energy storage capacity and heat release efficiency are significantly improved compared to DCG-CaO without Al2O3 load,but as the number of cycles increases,they decrease slightly and the interaction between Al2O3 and CaO will also lose part of the energy storage capacity of CaO.Therefore,based on the mass ratio of DCG-CaO/Al2O3 as 9∶1 and further introduction of MgO with higher heat capacity,the DCG-CaO/MgO/Al2O3 composite was prepared by the wet mixing method of DCG and the three-step SGCS method with the corresponding nitrates.It was found that the energy storage capacity and heat release efficiency of the CaO composite absorbent prepared by the three-step method were stable at 2.59 kJ/g and 90.55％respectively.It not only has more outstanding energy storage capacity and cycle stability but also avoids the interaction between CaO and Al2O3 Therefore,it has great application potential and development prospect.

Abstract:Calcium-based thermochemical energy storage technology utilizes reversible reactions(namely,CaO/CaCO3 and CaO/Ca(OH)2 systems),to achieve efficient thermal energy storage and release.This technology can be integrated with solar thermal energy to drive the calcination reaction for heat storage,while the carbonation exothermic reaction provides high-temperature heat during peak electricity demand for power generation.This effectively mitigates the intermittency of solar energy and promotes the operational flexibility and power generation capacity of power plants.With advantages such as wide availability of raw materials,low cost,and high energy storage density,calcium-based thermochemical energy storage is regarded as a highly promising large-scale thermal energy storage technology.calcium-based materials are susceptible to sintering-induced deactivation and mechanical wear during long-term cycling,a problem exacerbated under solar irradiation conditions.Additionally,challenges exist in reactor structural design and system integration optimization.This paper systematically reviews recent advances in the integration of calcium-based thermochemical energy storage with concentrated solar power generation.It focuses on three critical areas:modification of energy storage materials,development of directly and indirectly irradiated reactors for solar thermal applications,and thermodynamic optimization of solar-driven calcium looping systems.The review summarizes key research efforts,identifies major technical bottlenecks,and outlines promising future research directions.

Abstract:Perovskite solar cells(PSCs),as an emerging photovoltaic technology,have attracted extensive attention from both the academic and industrial communities worldwide due to their excellent photoelectric conversion efficiency,low raw material costs and mild solution processing technology.Since its first report in 2009,the efficiency of the laboratory's certification process has soared from the initial 3.8％to over 27％,demonstrating significant commercial potential.However,during the commercialization process,there are still some problems such as poor long-term stability,difficulties in scalable fabrication,performance degradation in large-area modules and relatively high production costs.From the dual perspectives of international policies and industrial layout,this review systematically examines the policy support and industrial guidance measures adopted by major countries and regions worldwide for the development of perovskite solar cells,along with the current commercialization status and key challenges.It further discusses the current landscape and future trends of leading domestic and international enterprises in terms of technological routes,production capacity deployment,and market strategies.In terms of industrialization challenges,four core issues are analyzed in detail:insufficient long-term stability,poor environmental safety,immature large-scale production processes,and incomplete cost structures and supply chain systems.The current mainstream technologies and corresponding strategies were summarized,such as additive engineering,packaging technology,multi-layer solar cell technology,upgrading of large-scale production processes,artificial intelligence collaboration,and diversified product application expansion.Finally,the future development of perovskite solar technology is envisioned.It was pointed out that perovskite solar technology will advance along the entire value chain through the integration of material innovation,process optimization,and industrial upgrading.Future progress is expected to focus on achieving higher efficiency,enhanced stability,and lower cost,thereby providing essential technological support for the transformation of the global energy structure and the realization of carbon neutrality goals.

Abstract:With the advent of the large-scale decommissioning period of photovoltaic modules,their resource treatment has become key to promoting the green development of the photovoltaic industry throughout its entire life cycle.To achieve efficient recovery of high-value materials such as aluminum,silver,and silicon,this study proposes a combined process of"thermal treatment+three-stage wet stepwise leaching".Retired crystalline silicon cells were mechanically crushed and thermally treated at 800℃,followed by a three-stage leaching process:primary leaching with hydrochloric acid/sulfuric acid to dissolve aluminum,secondary leaching with nitric acid to extract silver,and tertiary leaching with hydrofluoric acid to remove the Si3N4 anti-reflection layer and purify silicon.The study systematically investigated the effects of parameters such as acid type,concentration,reaction time,liquid-solid ratio,and temperature on the leaching behavior at each stage.The results showed that under the conditions of HCl with mass fraction 10％,a liquid-solid ratio of 5∶1 mL/g,50 ℃,and 30 min,the primary leaching achieved an aluminum leaching rate exceeding 80％,with a silver leaching rate below 3％,demonstrating good selectivity for aluminum.Increasing the HCl concentration or using H2SO4 with mass fraction 60％could increase the aluminum leaching rate to over 94％,but silver dissolution significantly increased,and the high concentration of sulfuric acid easily caused operational issues.In the secondary leaching,low-concentration nitric acid(mass fraction 15％)showed relatively high silver leaching performance due to reduced aluminum surface passivation;increasing the liquid-solid ratio to 8∶1 mL/g promoted silver dissolution,while raising the temperature to 70 ℃ decreased the leaching rate due to nitric acid volatilization.In the tertiary leaching,under the conditions of HF with mass fraction 5％,25℃,50 min,and a liquid-solid ratio of 5∶1 mL/g,the anti-reflection layer was effectively removed,yielding silicon powder with a purity exceeding 60％;the HF system was sensitive to reaction time and temperature,with lower temperatures favoring reduced volatilization and extended reaction time significantly increasing silicon content.This stepwise leaching process fully utilizes the differences in reactivity of aluminum,silver,and Si3N4 in different acid media,achieving sequential separation and enrichment of multiple components,significantly improving reagent utilization efficiency,and reducing the consumption of strong acids and waste liquid discharge.Compared to direct single-step wet processing,this process demonstrates clear advantages in aluminum/silver selectivity,silicon recovery purity,and environmental friendliness,providing a reliable technical pathway for the high-value recycling and industrial application of decommissioned crystalline silicon photovoltaic modules.

Abstract:Solar energy is widely used under the carbon neutrality target of carbon peak.The increase of the temperature of the photovoltaic panel will significantly reduce the photoelectric conversion efficiency,so the effective cooling of the photovoltaic panel is the key to improve the efficiency of solar power generation.Aiming at the problem of high temperature and low efficiency of photovoltaic panels on sloping roofs in rural areas,this paper proposes a method to optimize heat transfer in photovoltaic systems on sloping roofs by adding partitions to the air flow channel between photovoltaic panels and roofs to take advantage of the"chimney effect".Based on this method,a slope roof photovoltaic experimental platform was built,and the verified CFD model was used for numerical simulation.By comparing the width-to-height ratio of the flow channel between five different baffles,the optimal width-to-height ratio is determined to be 1∶1.Based on this model,the effects of ambient wind speed,roof inclination and photovoltaic array length on the"chimney effect"are studied.The results show that the average temperature of photovoltaic panels decreases with the increase of the ambient wind speed,roof inclination angle and photovoltaic array length.When the ambient wind speed increases from 0.2 m/s to 5.0 m/s,the average temperature of the photovoltaic panel decreases from 64.31 ℃ to 49.06 ℃.When the roof inclination angle increases from 20° to 35°,the temperature of each part of the photovoltaic panel decreases slowly.When the roof inclination angle increases from 35° to 50°,the temperature of each part of the photovoltaic panel decreases faster.The average temperature on the photovoltaic panel decreased from 61.62℃ to 55.66℃.When the length of the photovoltaic array increases from 1 to 5,the average temperature of the photovoltaic panel decreases from 64.68℃ to 57.65℃.

Abstract:Aiming at addressing the critical issues of power supply,heating,oxygen supply,and purified water provision for buildings in alpine and high-altitude areas,this study proposes a distributed energy system based on photovoltaic power generation,taking a typical single-story building in Lhasa,Tibet Autonomous Region,as the research object.Simulation calculations using DeST software determined the building's average heating index to be 51.82 W/m2 and the annual electricity demand to be 3 040.4 kWh.A mathematical model of the system was established,incorporating PV generation,air-source heat pumps,a hydrogen-oxygen production system via electrolysis,energy storage systems,and fuel cells.The system's annualized cost,energy self-sufficiency rate,and energy system efficiency were set as optimization objectives.The optimization process involved efficient solving using the CPLEX and IPOTO solvers.The normalized weighted sum method was employed to obtain the Pareto solution set for system capacity configuration.The entropy weight-TOPSIS method was then applied for multi-dimensional evaluation of the solution set,determining the weight distribution among the three objectives as 0.23,0.29,and 0.48,respectively,thereby obtaining the optimal system capacity configuration.The optimization results show an annualized cost of 8 700 yuan,an energy self-sufficiency rate of 87.59％,and an energy system efficiency of 83.34％.Power balance analysis on typical days verified the system's capability for multi-energy flow coordination across different seasons,demonstrating that the configured system achieves good economic performance and stability while meeting complex load demands,and realizes reliable operation and multi-energy complementarity under extreme environmental conditions.Finally,sensitivity analysis identified the photovoltaic feed-in tariff and the coefficient of performance of the heat pump unit as the primary factors influencing the investment payback period and the energy system efficiency,respectively.This study provides theoretical support for the integrated design and application of distributed energy systems in buildings located in alpine and high-altitude regions.

Abstract:With the large-scale integration of renewable energy into power grids,the demand for flexible regulation of coal-fired power units is increasing.Complementary operation between solar energy and coal-fired units is considered an effective approach to enhancing system flexibility and reducing carbon emissions.Meanwhile,biomass,as another form of green renewable energy,can be co-fired or thermochemically coupled with coal units to partially replace coal and further reduce carbon emissions.Based on this concept,a novel system integrating a coal-fired unit with solar-driven biomass supercritical water gasification(SCWG)is proposed.In this system,a portion of the main steam from the coal-fired boiler is extracted to participate in the solar-driven SCWG process,achieving synergistic coupling among coal,solar,and biomass energy sources.During gasification,biomass reacts with high-temperature and high-pressure water to produce CH4,H2,and CO gases,which are subsequently converted into CH4 through a methanation process and stored in a gas tank.When the grid load fluctuates,the stored methane can be rapidly fed into a gas turbine for power generation,leveraging its high ramping rate to compensate for the slower response of the coal unit.This forms an integrated"electricity-heat-gas"multi-energy complementary regulation mechanism.A solar-biomass supercritical water gasification coupled coal-fired power plant system is established based on Aspen HYSYS.The effects of key parameters such as gasification temperature and water-carbon ratio(the molar ratio of water to carbon in biomass)on the thermodynamic performance of the supercritical water gasification process are analyzed.The system's overall performance-energy conversion efficiency,specific coal consumption,and ramping capability-was evaluated under typical operating conditions.Results show that at 50％load,a gasification temperature of 700℃,and a steam-to-carbon ratio of 1.3,the total energy conversion efficiency reaches 71.27％,with methane accounting for 56.03％of the total energy output as the primary energy carrier,and net electricity generation accounting for 15.23％.Across the 20％-75％load range,the system efficiency remains stable between 61.29％and 73.75％,indicating excellent stability and flexibility in the coordinated operation of solar and coal-fired units.Compared with conventional coal-fired units,the proposed system exhibits significant potential for coal consumption reduction under deep peak-shaving conditions.The specific coal consumption of a traditional unit rises to 311.49 g/kWh at 30％load,whereas the coupled system achieves 242.85 g/kWh at 20％load,showing a marked improvement in efficiency.The system employs a Mitsubishi 701F gas turbine(240 MW),which has the potential to enhance the overall system ramp rate to 15.3 MW/min.The proposed coal-fired unit coupled with solar energy and biomass supercritical water gasification not only improves the flexibility of coal-fired power plants,but also offers the potential for reducing coal consumption,efficiently utilizing biomass conversion,and ensuring grid security and flexible dispatch.

Abstract:In recent years,immense attention is attracted by the implementation of amine functionalized solid adsorbents for direct air capture(DAC)of CO2.However,a great reduction of pore volume and specific surface area within the adsorbents is led to by the amine functionalization of traditional supports(such as SBA-15).In the context of DAC,the CO2 adsorption dynamics is significantly limited by the extremely low partial pressure of CO2(400×10-6),thus with lower CO2 adsorption capacity.To address this issue,silica hollow spheres(RHMS-4)with large pore aperture and high structural tunability are prepared by using phenolic resin microspheres as templates and adjusting the mass fraction of tetraethyl orthosilicate(TEOS)with the introduction of a reaming agent.The amine functionalization is achieved by impregnating silica support in tetraethylenepentamine(TEPA)solution.The structure-performance relationship of RHMS-4-TEPA series adsorbents is investigated by XRD,FT-IR,and other characterization techniques.The effect of amine content,adsorption temperature and ambient humidity on the CO2 adsorption capacity are also investigated.The experimental results show that:Under dry condition(50 ℃ and 400×10-6 CO2),the adsorption capacity of RHMS-4-TEPA70 reach to about 2.400 mmol/g,while the CO2 uptake is improved by about 42％with the presence of moisture.After 10 sorption-desorption cycles,relatively high CO2 adsorption capacity and excellent cycling stability are still maintained by RHMS-4-TEPA70.

Abstract:Solar energy is characterized by enormous reserves,cleanliness,and low carbon emissions.Vigorously developing solar energy constitutes a key pathway to achieving the"dual carbon"goals.Photon-Enhanced Thermionic Emission(PETE)is an emerging solar power generation technology that couples the photovoltaic effect with the thermionic effect.It boasts advantages such as high efficiency,simple structure,and stable operation,thus demonstrating great development potential.Solar PETE systems are strongly coupled light-heat-electricity systems,and the establishment of their theoretical models is crucial for the development and research of PETE technology.However,the mathematical and physical models for light-heat-electricity coupling typically suffer from high computational costs and low efficiency.A back propagation(BP)neural network model is employed to predict the power generation performance of PETE systems.Three parameters,concentration ratio,electron affinity,and cathode thickness,are selected as input variables,while six key indicators,including cathode temperature and energy conversion efficiency,serve as output targets.A research sample is constructed using 990 sets of numerical simulation data.The dataset is divided based on the latin hypercube sampling(LHS)method,and logarithmic preprocessing is applied to the photon enhancement coefficient to optimize data distribution.The constructed BP neural network features a node configuration of 3-10-12-6.The Levenberg-Marquardt algorithm is adopted for model training,with two complementary metrics,the coefficient of determination(R2)and mean absolute percentage error(EMAP),used for evaluation.Results show that the model achieves extremely high prediction accuracy for all six parameters,with R2 values exceeding 0.99 and EMAP values approaching 0.Validation using the test set confirms that the model exhibits strong generalization ability.Compared with traditional numerical simulations,the prediction speed is significantly improved,enabling real-time optimization of the system.The effectiveness of the BP neural network model in predicting the performance of solar PETE power generation systems is verified,and an efficient approach for their development and application is provided.

Abstract:To expand the resource utilization of fly ash,the desulfurization performance of fly ash as a desulfurization agent for wet flue gas desulfurization was studied using a flue gas desulfurization simulation device;And use the slurry of wet desulfurization with fly ash to prepare filling paste(desulfurization group),and compare the performance of ordinary fly ash filling paste(blank group);The pollution risks of Pb,Cr,Cd,Hg,Zn,As,Cu ions in two types of filling pastes were analyzed using the Nemero comprehensive pollution index method and the Hakanson potential ecological risk index method.The results show that under the conditions of wet desulfurization experiment,the desulfurization efficiency of coal ash slurry is high,and the duration above 95％increases with the increase of slurry concentration;The compressive strength of the desulfurization group at curing period of 3,7,14,and 28 days is 0.83,1.59,3.52,and 4.09 MPa,which is 1.5,1.1,1.26 and 1.3 times higher than that of the blank group with the same ratio.The slump,bleeding rate,initial setting time,and final setting time are reduced by 5.2％,6.5％,13.6％,and 11.1％compared to the blank group,respectively;The evaluation results using the Nemero index method indicate that the comprehensive pollution index of the desulfurization group is 0.517 4,indicating a safe level of pollution.The comprehensive pollution index of the blank group is 0.946 7,indicating a relatively safe level of pollution.The results of the Hakanson potential ecological risk index method indicate that the ecological hazard index of the desulfurization group is 8.848,while the ecological hazard index of the blank group is 31.509,and the risk level is mild.It can be seen that the risk of metal contamination in the filling paste prepared from desulfurized fly ash slurry has been reduced,making it suitable for use as a filling paste.

Abstract:Under carbon peaking and carbon neutrality goals,the demand for energy transition in China is increasingly urgent.Addressing the inherent challenges of solar energy,such as its discontinuous temporal distribution(day-night cycles)and uneven seasonal availability(summer-winter variations),through advanced energy storage technologies is a critical bottleneck that needs to be overcome.This study proposes a solar thermal power generation system integrated with a CaO/Ca(OH)2 thermochemical energy storage system for cross-seasonal energy storage.The system features a fast-response and technologically mature MgCl2/KCl molten salt storage system for daily energy storage,coupled with a high-energy-density and low-loss CaO/Ca(OH)2 thermochemical storage system for seasonal energy storage.By synergistically combining these two systems,the proposed solution enables"daytime energy for nighttime use"and"summer energy for winter use",significantly improving the annual utilization efficiency of solar energy.A 100 MWe integrated solar power generation system with cross-seasonal energy storage was designed,comprising a tower-based solar concentrator subsystem,a molten salt storage subsystem,a calcium-based thermochemical storage subsystem,a supercritical CO2 Brayton cycle power generation subsystem,and an organic Rankine cycle power generation subsystem.To accommodate varying daily and seasonal operational conditions,six system operation modes were proposed,including daytime and nighttime modes for summer,winter,and transitional seasons,along with corresponding control strategies.Dynamic performance simulations were conducted using hourly meteorological data from Lenghu Town,Qinghai Province,China.The results demonstrate that the system generates 187.01,183.08,178.42,and 180.14 GWh of electricity in spring,summer,autumn,and winter,respectively.The annual average values for system energy efficiency and solar power generation efficiency are 26.24％and 21.09％,respectively.Notably,under a summer-to-winter solar energy input ratio of 1.509(indicating a seasonal fluctuation of 50.9％),the power generation ratio remains at 1.016(indicating a seasonal fluctuation of 1.6％),significantly mitigating the fluctuations in electricity output caused by seasonal solar energy variability.

Abstract:Under the backdrop of"carbon neutrality",the synergistic conversion of methane and carbon dioxide is considered one of the key pathways to achieve greenhouse gas emissions reduction and high-value utilization of carbon resources.However,the current methane dry reforming process suffers from high energy consumption,severe side reactions,and difficulty in product control;while the electrocatalytic CO2 reduction process faces issues such as poor temperature matching,high electrical energy consumption,and low reaction efficiency.How to achieve efficient synergy among heat sources,power sources,and carbon sources,and establish an integrated energy conversion system,has become a major challenge in this field.To address the aforementioned issues,a solar-powered"methane co-reforming-high-temperature co-electrolysis"coupled system has been proposed.This system utilizes photothermal catalysis to simultaneously convert CH4,CO2,and H2O into synthesis gas,while also producing high-temperature exhaust gas to provide a stable heat source and reactants for the downstream co-electrolysis unit,thereby synergistically achieving the electrolytic reduction of CO2 and H2O,forming an efficient carbon conversion pathway.For this system,a dual-module numerical model of thermal catalysis and electrocatalysis was constructed to systematically analyze its reaction performance and energy utilization efficiency under different conditions such as intake temperature,mole fraction,and feed ratio.The results show that the synergistic reforming system can increase methane conversion rates by 2.40％to 64.83％and solar-to-fuel efficiency by 2.70％to 53.92％.After introducing the co-electrolysis system,the electrolysis efficiency is significantly improved,reaching a maximum of 99.47％,an increase of nearly 30％compared to ambient temperature conditions.Increasing the CO2 feed ratio further enhances the overall synergistic efficiency of the system.The thermo-electrochemical synergistic system constructed in this study not only effectively integrates the"heat source-water source-carbon source"chain,achieving hierarchical energy utilization and maximizing carbon resource conversion,but also provides a theoretical foundation and technical pathway for the construction of solar multi-energy integration utilization and green synthesis gas platforms.

Abstract:Microalgae can convert CO2 into energy-rich organic matter through photosynthesis.With advantages such as high photosynthetic efficiency and no competition with food crops for arable land,microalgae-based carbon reduction technology is recognized as a key approach to achieving China's carbon peaking and carbon neutrality goals.Light intensity and nitrogen availability are two crucial factors influencing the photosynthetic growth and metabolite synthesis of microalgae.While light provides the energy driving photosynthesis,nitrogen is essential for the synthesis of pigments-the cellular"light absorbers"—highlighting the need for coordinated regulation of light and nitrogen.Moreover,the optimal requirements for light and nitrogen vary with growth stages and target metabolite types.To achieve economically efficient carbon sequestration and organic matter production,this study proposes a light-nitrogen synergistic phased regulation strategy,in which light intensity is gradually increased and nitrogen is supplied in two distinct stages,based on the specific requirements of Chlorella vulgaris at different growth phases.The effects of this light/nitrogen phased control on the microalgal photosynthetic growth rate,CO2 fixation rate,and organic composition were systematically investigated.The results showed that pigment content in microalgal cells was positively correlated with the initial nitrogen mass concentration.Under low nitrogen conditions(NaNO3 mass concentration of 0.15-0.55 g/L),lipid accumulation was favored,while nitrogen-rich conditions(0.75-1.05 g/L)led to higher protein and carbohydrate contents which increased by 20％.The maximum carbon dioxide fixation rate of microalgae was increased by 13％to 0.56 g/Ld by synergistic regulation of light intensity and nitrogen source mass concentration during microalgae growth.The maximum biomass concentration of microalgae increased by 14.78％and the percentage of oil quality increased by 36.2％,which realized the synchronous improvement of microalgae yield and productivity.Therefore,the coordinated regulation of light,nitrogen and energy proposed in this study is an effective method to improve the carbon fixation efficiency of microalgae.