Thermochemical splitting of CO_(2) on perovskites for CO production: A review

Energy supply dominated by fossil energy has been and remains the main cause of carbon dioxide emissions,the major greenhouse gas leading to the current grave climate change challenges.Many technical pathways have been proposed to address the challenges.Carbon capture and utilization(CCU) represents one of the approaches and thermochemical CO_(2) splitting driven by thermal energy is a subset of the CCU,which converts the captured CO_(2) into CO and makes it possible to achieve closed-loop carbon recirculation.Redox-active catalysts are among the most critical components of the thermochemical splitting cycles and perovskites are regarded as the most promising catalysts.Here we review the latest advancements in thermochemical cycles based on perovskites,covering thermodynamic principles,material modifications,reaction kinetics,oxygen pressure control,circular strategies,and demonstrations to provide a comprehensive overview of the topical area.Thermochemical cycles based on such materials require the consideration of trade-off between cost and efficiency,which is related to actual material used,operation mode,oxygen removal,and heat recovery.Lots of efforts have been made towards improving reaction rates,conversion efficiency and cycling stability,materials related research has been lacking-a key aspect affecting the performance across all above aspects.Double perovskites and composite perovskites arise recently as a potentially promising addition to material candidates.For such materials,more effective oxygen removal would be needed to enhance the overall efficiency,for which thermochemical or electrochemical oxygen pumps could contribute to efficient oxygen removal as well as serve as means for inert gas regeneration.The integration of thermochemical CO_(2) splitting process with downstream fuel production and other processes could reduce costs and increase efficiency of the technology.This represents one of the directions for the future research.

Energy storage for black start services:A review

With the increasing deployment of renewable energy-based power generation plants,the power system is becoming increasingly vulnerable due to the intermittent nature of renewable energy,and a blackout can be the worst scenario.The current auxiliary generators must be upgraded to energy sources with substantially high power and storage capacity,a short response time,good profitability,and minimal environmental concern.Difficulties in the power restoration of renewable energy generators should also be addressed.The different energy storage methods can store and release electrical/thermal/mechanical energy and provide flexibility and stability to the power system.Herein,a review of the use of energy storage methods for black start services is provided,for which little has been discussed in the literature.First,the challenges that impede a stable,environmentally friendly,and cost-effective energy storage-based black start are identified.The energy storagebased black start service may lack supply resilience.Second,the typical energy storage-based black start service,including explanations on its steps and configurations,is introduced.Black start services with different energy storage technologies,including electrochemical,thermal,and electromechanical resources,are compared.Results suggest that hybridization of energy storage technologies should be developed,which mitigates the disadvantages of individual energy storage methods,considering the deployment of energy storage-based black start services.

Filtration characteristics of a binary multi-layer granular bed flter based on CFD-DEM coupling simulation

The coupled CFD-DEM method with the JKR(Johnson-Kendall-Roberts)model for describing the contact adhesion of dust to filter particles(FPs)is used to simulate the distribution pattern of dust particle deposition in the granular bed filter(GBF)with multi-layer media.The minimum inlet flow velocity must meet the requirement that the contact probability between dust and FPs is in the high contact probability region.The air flow forms vortices on the leeward side of the FPs and changes abruptly at the intersection of different particle size FPs layers.Dust particles form large deposits at the intersection of the first and second layers and the different particle size filter layers.Dual element multilayer GBF can further optimize the bed structure by interlacing filter layers with different particle sizes.Compared with single particle size multi-layer GBF,the bed pressure drop is reduced by 40.24%-50.65%and the dust removal efficiency is increased by 21.93%-55.09%.

篮状菌Talaromyces leycettanus JCM12802来源的高温葡萄糖淀粉酶性质与结构

葡萄糖淀粉酶作为淀粉糖化的关键用酶之一,广泛应用于食品、医药和发酵工业等行业。由于整个制糖过程都是在高温下完成的,因此对葡萄糖淀粉酶的反应温度和热稳定性有较高要求。本研究从嗜热篮状菌Talaromyces leycettanus JCM12802中克隆到一个糖苷水解酶第15家族(GH15)葡萄糖淀粉酶基因(Tlga15A)并在毕赤酵母GS115中实现异源表达。重组葡萄糖淀粉酶TlGA的最适pH为4.5,在75℃下表现出最高酶活。TlGA热稳定性好,65℃条件下处理1 h剩余70%以上酶活力;70℃处理30min后仍有43%酶活力。TlGA有较强的离子抗性和宽泛的底物特异性,TlGA水解可溶性淀粉、支链淀粉、糖原、糊精和普鲁兰的比活力分别为(255.6±15.3) U/mg、(342.3±24.7) U/mg、(185.4±12.5) U/mg、(423.3±29.3) U/mg和(65.7±8.1) U/mg。从葡萄糖淀粉酶TlGA的一级结构、二级结构和三级结构3个层面对其进行比较分析,发现一级结构中较少的Gly组成和三级结构中较低的非极性基团溶剂可及表面积可能是维持葡萄糖淀粉酶TlGA温度稳定性的主要原因。综合其性质特点和对结构的分析,葡萄糖淀粉酶TlGA在工业葡萄糖生产中有较大应用潜力。

Experimental study on filtering mixed solid-liquid dust with a sliding granular bed filter

The filtration of mixed dust that included a small number of melted(liquid)particles was studied in an experimental granular bed filter(GBF).Results show that the collection efficiency of dust containing melted particles is higher than that of dust composed of solid particles but the pressure drop from the former is higher than that of the latter.The collection efficiency and pressure drop increase as the concentration of melted particles increases.A surface sliding GBF exhibits good comprehensive performance when filtering dust,especially dust containing a mix of solid and liquid particles.The effects of the gas temperature,gas velocity,sliding filter bed thickness,and sliding collector flux on filter performance were also examined.Based on the experimental results,correlations for the collection efficiency and pressure drop for mixed dust are presented.

Dust distribution of solid and adhesive mixed dust in a granular bed filter

Granular bed filters can effectively filter adhesive dust in high-temperature flue gas.In this study.polyvinyl chloride(PVC)powder was used as adhesive dust,and the mixture of PVC and ash powder was used to simulate solid and adhesive mixed dust.The effects of gas temperature,velocity,and inlet adhesive dust mass content on dust distribution in granular bed(GBF)were discussed.Results show that the mixed dust mainly accumulates on the upper part of the granular bed,and the mass of the collected dust decreases exponentially from the upper layer to the bottom layer in the GBF.The adhesive dust content collected in each layer differs from that of the incoming dust,and their deviation varies approximately linearly along with the depth of the bed.The total dust distribution and adhesive dust content deviation are influenced by gas temperature and inlet adhesive dust content but independent of gas velocity.The correlations of dust distribution of solid and adhesive mixed dust are presented based on the experimental results.

Carbon capture and storage(CCS):development path based on carbon neutrality and economic policy

In order to limit global warming to 2°C,countries have adopted carbon capture and storage(CCS)technologies to reduce greenhouse gas emission.However,it is currently facing challenges such as controversial investment costs,unclear policies,and reduction of new energy power generation costs.In particular,some CCS projects are at a standstill.To promote the development of CCS projects in different countries,this paper reviews and compares energy conservation and emission reduction policies and different national goals.From a policy perspective,CCS-driven policies are analyzed.Based on this,corresponding policy recommendations are put forward,in order to promote the healthy development of global CCS technology and deal with climate issues more effectively.With less than 10 years away from the short-term goal,promoting the development and application of CCS projects requires scientific research from universities,enterprises and governments in order to attain zero or negative CO_(2)emission.On the basis of focusing on the development of CCS technology,according to the actual situation of each country,the appropriate application of CCS engineering should focus on the development of science and technology,rather than a unified requirement around the world.