The essence of achieving "carbon emission peak" and "carbon neutrality" is to completely get rid of the dependence of economic and social development on carbon-containing mineral resources. The key solution towards this issue is to develop innovative science and technology. As an efficient and energy-saving generic separation technology, what role can membrane technology play in this process? This paper discusses the important functions of membrane technology in the pivotal technical approaches to realizing "carbon emission peak" and "carbon neutrality" targets from four aspects: zero-carbon energy system reconstruction, low-carbon-process engineering, non-CO₂ gas emission reduction and negative-carbon-system creation. The involved technical approaches mainly included zero-carbon-electricity storage, green hydrogen preparation and utilization, process optimization and energy consumption reduction of current industrial processes, CO₂ and non-CO₂ gas capture, CO₂ conversion and reuse. The recent developments of membrane technology in the relevant fields are analyzed, and the future development directions and goals of the membrane technology in China are prospected. It is anticipated that the large-scale applications of various disruptive membrane technologies in the future could contribute to achieving the two strategic objectives of the lowest renewable energy cost in the world and the minimum price of low-carbon-process engineering, and then provide technical supports for realizing "carbon neutrality" in China.

Carbon capture is one of the most critical technical means to reduce CO₂ emissions. Compared with various carbon capture technologies, membrane separation features operational simplicity, low energy consumption and low ecological footprint, which has attracted wide attention. The complete research chain of membrane technology for CO₂ separation includes the development of membrane materials, the large-scale preparation of membranes, the structural design of membrane modules, and the integrated simulation and optimization of membrane separation processes and devices. Focusing on the above four links to develop the CO₂ separation membrane technology, this article reviews the technical and research progress worldwide and analyzes the bottleneck problems of the CO₂ separation membranes from laboratory research to industrial scale-up. The research results accumulate by the team led by Tianjin University in each technical link are also summarized. Based on the above description, the possible research direction to further develop membrane technology for carbon capture is proposed.

CO₂ capture with a low energy consumption is of application significance for reducing CO₂ emission. Chemical absorption, commercialized for decades, has been regarded as an effective method for CO₂ capture. However, a high energy consumption and a high cost limit the large-scale industrial applications. Some new absorbents and specific devices are developed. With the reduce of energy consumption of chemical absorption, several demonstration projects have been established in China recently. And reducing the capture energy consumption and lowering the capture cost are the constant pursuits for achieving “carbon neutrality”. The following suggestions of chemical absorption are proposed on the basis of the previous researches: developing a broadly applicable absorption theory for phase-change absorption system, building an database of the absorption systems, and establishing some quantitative models are proposed for effectively developing new solvents for CO₂ absorption; strengthening the gas-liquid mass transfer and designing heat transfer components with high performance are proposed for improving carbon capture efficiency; coupling chemical absorption and mineralization are proposed to achieve in-situ CO₂ absorption and fixation, which may increase the economy of the process. All those accumulated researches are expected to promote carbon capture and to achieve “carbon neutrality”.

As the global high-quality energy carrier, hydrogen can be produced via thermochemical processing of hydrocarbons, such as natural gas, coal and biomass, or water electrolysis using any source of electricity including renewables, such as wind, solar or nuclear power. The current technology of water electrolysis is not economically competitive for large-scale hydrogen production, and there is an eager need to develop new technologies for green hydrogen production. A dramatic transformation towards renewable and low carbon hydrogen production must be taken to achieve the carbon neutrality in 2060. It is predicted that the low carbon hydrogen production by steam reforming of hydrocarbons with carbon capture, utilization and storage (CCUS) will be dominating, and gradually afterward shifted to renewable hydrogen production together with low carbon hydrogen production, and even negative carbon hydrogen production and fully realize zero-carbon hydrogen production. China has rich biomass resource, however, the technology readiness level of hydrogen from biomass wastes is still relatively low. There is an eager need to develop new technology for efficient renewable hydrogen production from biomass to increase the hydrogen yield and lower the cost significant. Sorption enhanced reaction represents a promising new technology for sustainable production of hydrogen. The hydrogen yield and purity are significantly increased by the process intensification. The process of hydrogen production can be intensified in multifunctional reactors, where reforming and/or gasification, water-gas shift (WGS) and CO₂ removal steps are integrated into one reactor over a mixture of reforming/WGS catalysts and CO₂ acceptors. Owing to it is huge potential, the process development of renewable hydrogen production from biomass wastes by combined gasification and sorption enhanced reaction should be accelerated. The process needs to be commercialized as soon as possible to catalyze the transitions to carbon neutral.

The low-, zero- or negative-carbon transformation of existing industrial processes relies on energy conservation, pollution reduction and carbon dioxide mitigation in the short term and substitution of traditional fossil resources with sustainable supplies in the long term. Wind, solar and hydropower electricity drives future energy supply. However, sustainable resources need to be explored to meet the increasing demands of materials and products. Biomass can be processed into fuels, materials, and chemicals, which is considered an important substitute of fossil resources. In the bio-energy route, technologies for scale-up production of bio-methane, bio-ethanol and bio-diesel have been well developed and pilot-plants have been established. The integration of biomass conversion with existing industrial process supports the carbon reduction of industrial processes, and it also has great potential to drive zero-carbon or even negative-carbon process in the future. By presenting biomass conversion examples such as biomass gasification for combined heating and power, co-combustion of biomass and coal, biomass-substituted fuel in cement production, this work puts forward the challenges of process integration with biomass conversion and calls for the establishment of new fundamental theories and breakthrough technologies.

The hydrogenation of CO₂ to dimethyl ether (DME) is a potential method for the efficient utilization of CO₂ as a renewable resource. In comparison with the photocatalytic and electrocatalytic routes, the thermal conversion of CO₂ over a solid catalyst exhibits a higher efficiency. However, the reported catalysts for the one-step hydrogenation of CO₂ to DME commonly suffer from a lower activity and a poorer stability. In this perspective, progresses on the structure of active sites and the reaction mechanism of the one-step hydrogenation of CO₂ to DME are summarized for the Cu-based bifunctional catalyst and the recently reported GaN catalyst. In the case of the Cu-based bifunctional catalyst, DME is formed via the CO₂ hydrogenation to methanol and the dehydration of the intermediate methanol to DME. Moreover, copper at reduced state (Cu⁰, Cu⁺ or Cu ^δ+, 0<δ<2) is the active site for the CO₂ hydrogenation, and the DME yield and the stability of the bifunctional catalyst are mainly determined by the dispersion and the stability of reduced Cu, the strength and distribution of acid sites, and the synergetic effect between reduced Cu and the acid sites. In contrast, the GaN catalyzed DME synthesis proceeds via the direct hydrogenation of CO₂ to the primary product of DME, which is totally different from that over the Cu-based bifunctional catalysts. Based on these analyses, the challenges and the further researches on the one-step hydrogenation of CO₂ to DME are provided, and the benefit of the DME economy is remarked.

Inorganic metallic carbonate is a kind of mineral resources with high supplementary value and abundant reserves on earth. The thermal decomposition of carbonate is the main way to prepare metal oxides. However, it usually requires roasting under high temperature and oxygen atmosphere, resulting in a large amount of carbon dioxide emissions. In addition, the total carbon emissions related to it exceed 50% of the national industrial carbon emissions. In order to resolve this problem, the thermal decomposition of inorganic metallic carbonate via hydrogenation reduction attract gradually much attention. This paper firstly introduces the research progress of the thermal composition of carbonate via hydrogenation reduction, combined with the latest results of hydrogen generation from electrochemical water splitting and carbonate reduction in our research group. A new technology model perspective of electrochemical water splitting coupling carbonate reduction is put forward, which can become a new technology route to prepare metal oxides. It is the significant reference for greatly reducing carbon emission and improve efficiency of heavy emission process industries.

The present carbon dioxide emission of the electric power industry from fossil resource is one of the principal sources for carbon dioxide emission in our country. To realize carbon neutrality, the development and utilization of renewable energy has been the strategic direction for the reform in the energy field. It is imperative to take great efforts developing low carbon and zero carbon energy system like renewable energy and constructing a new energy-based electric power system. Photovoltaic power generation is one of the main ways for power generation of renewable energy. Here, the present situation and problems on the utilization of photovoltaic power generation, the key technologies, development tendency in future and related strategies are analyzed. The crystalline silicon solar cells, thin film solar cells (silicon, gallium arsenide, copper indium gallium selenide, cadmium telluride), perovskite solar cells and other new types of solar cells (organic solar cells, dye-sensitized solar cells, quantum dos solar cells) are stated in detail. These can provide scientific basis for the rapid development of photovoltaic industry and the construction of an efficient and safe new system of clean energy.

Under the background of global warming and China’s "double carbon" goal, the concept of "chemical wastewater treatment and CO₂co-utilization" is proposed in this paper, and purified terephthalic acid (PTA) production wastewater treatment and CO₂co-utilization are selected to produce microalgal biomass. Laboratory study and pilot test lasted for 124 days are carried out. The experimental results show that the COD removal rate is more than 92%, the CO₂ (10%volume fraction) capture rate is more than 93%, and the CO₂ capture intensity was 9—11kg/t wastewater. The residual biomass is treated by pyrolysis, and the pyrolysis rate of biomass is >95%. A closed-loop carbon conversion and utilization system is applied to treat and utilize carbon in wastewater, gases and solids. The conversion from "useless carbon" to "usable carbon" is realized, which provided a new way for the goal of carbon neutralization in chemical enterprises.

The global warming caused by excess carbon dioxide (CO₂) emission has been a worldwide focus. The development of carbon neutralization technologies is a strategic choice for the sustainability of human society. CO₂ capture and conversion to high value-added chemicals is an ultimate technology for the goal of carbon neutralization, which can optimize the fossil fuel-dominated energy structure, effectively alleviate environmental problems, and achieve carbon recycling. This paper focuses on the efficient CO₂ utilization by the route of CO₂-syngas-high value-added chemicals. As an important intermedia product, syngas is the most feasible for CO₂ conversion and can be further transformed into value-added chemicals. Recent progresses in three CO₂ to syngas technologies of thermo-catalysis, electrocatalysis and photocatalysis are reviewed, including the mechanism, catalysts design strategies, and the current industrial application prospects. Moreover, the conversion of syngas to light olefins and aromatics through the Fischer-Tropsch synthesis and relay catalytic routes are also reviewed. By analyzing and comparing the key technologies, we summarize the challenges of catalyst design and reactor optimization for the large-scale industrial applications of CO₂ to syngas and further to high value-added products, and proposed the prospects of CO₂ capture and utilization. At the same time, the problems of unclear reaction mechanism, high cost of catalysts and lack of large-scale producing are explained. The effort to promote application of the technologies in the future is to develop low-cost and long-life catalyst with high activity and efficiency.

The emerging carbon-negative technologies like direct air capture (DAC) guarantee the carbon neutral and therefore receive growing attention. In this study, the characteristics of DAC are briefly analyzed. Amine-functionalized inorganic materials, polymers, metal hydroxides and carbonates are compared and reviewed in terms of trace carbon dioxide capture performance. And the relationship between adsorption capacity and kinetics with loading methods, and hierarchy texture of support are clarified. Finally, the challenges in this field and the suggestions from the point of energy-consuming and capture efficiency are put forward. Firstly, amine functionalized materials and solid base sorbent display better potential in practical application than physisorption materials. Secondly, integration and use of the existed deep removal processes as references could develop and optimize the process. At last, facing the sever environmental problems, the development of the new material and low energy-consuming regeneration method should be concentrated in the future.

Carbon dioxide conversion to value-added chemicals is one of the effective strategies to achieve the “carbon neutral” target. Carboxylation of unsaturated hydrocarbons with CO₂ as carboxyl source and transition metal as catalyst is a new technology for valuable utilization of CO₂ to synthesize acrylic acid derivatives. This review summarizes the application of different metal catalysts (Ni, Pd, Cu, etc.) in the carboxylation of CO₂ with olefins, alkynes, and allenes, which focuses on the metal-ligand optimization and the regulation of reaction conditions in different catalytic systems. The catalytic characteristics and mechanism of different catalysts are systematically compared, and some key issues such as the rate-controlling step in the catalytic reaction cycle and catalyst regeneration are discussed. Finally, the future research directions and applications of the catalytic reaction systems involving the above three unsaturated hydrocarbons are prospected. It is speculated that the process of coupling carboxylation of CO₂ and ethylene to prepare acrylic acid has industrial prospects, while the development and optimization of the related reactions in the reductive carboxylation systems of CO₂ with alkynes or allenes would provide new ideas for the efficient synthesis of highly regioselective unsaturated carboxylic acid derivatives.

Ionic liquids (ILs) and deep eutectic solvents (DESs) have been widely used in the conversion of CO₂ to organic carbonates due to their excellent dissolving capacity and catalytic performance. In this work, the progress of CO₂ conversion to organic carbonates catalyzed by ILs and DESs is reviewed. The catalytic performance of ILs and DESs for CO₂ converted to dimethyl carbonates and cyclic carbonates and the reaction mechanism are introduced, where the ILs mainly include conventional ILs, protic ILs, and functionalized ILs while the DESs consist of choline chloride, quaternary ammonium salts, quaternary phosphine salts, or organic bases as hydrogen bond acceptor. The basic principles of catalyst design for these reaction systems are analyzed. However, the transformation of CO₂ to organic carbonates with ILs and DESs are facing the problems of low activity, low stability and subsequent separation difficulties. Therefore, future research could utilize computer-aided design to explore efficient ILs and DESs of new structures.

The use of new adsorbent materials to adsorb and separate CO₂ and catalytically convert them into high value-added products, which has the advantages of green and clean, and is one of the important technological choices for the global response to climate change in the future. However, the CO₂ capture process in a complex environment has the problems of inefficient adsorption and separation and high cost. This article briefly describes the latest research progress of CO₂ adsorption materials and effective ways of resource utilization, mainly introducing the influence of the physical and chemical properties of adsorption materials such as metal-organic framework (MOF), molecular sieves, porous carbon materials and covalent organic framework (COF) on adsorption capacity and selectivity. From the perspective of catalytic conversion, the synthesis of small molecule compounds such as formic acid, methanol and olefins are discussed. Based on the comprehensive treatment of CO₂ waste gas, the feasibility of hydrogenating flue gas and blast furnace gas in the iron and steel industry is discussed, which opend up new ideas in the scientific and technological progress of CO₂ capture and conversion. It is prospected for the cleaner and more efficient use of CO₂, and the realization of low-carbon, intelligent and multi-energy integration.

In the context of carbon neutrality, the carbon dioxide utilization, as an important low carbon technology, has received extensive attention from academia and industry, the low carbon performance evaluation becomes very important for the top-level design of technology research and layout. However, the existing researches mainly focus on qualitative priority judgment of technical characteristics, and lack of systematic evaluation method. This paper firstly combed the development status of carbon dioxide utilization technology, and then based on the four aspects of technical characteristics, carbon neutralization effect, economic effect and social effect, a comprehensive low carbon performance evaluation methodology had been constructed by combining the method of analytic hierarchy process and proximity to target, and it had been applied to current status and future potential low carbon performance evaluation of the typical carbon dioxide utilization technology in China. Through the horizontal low carbon performance comparison of different carbon dioxide utilization technologies and the vertical low carbon performance comparison of different technologies at different stages, the results showed that at the present stage, the overall low carbon performance of carbon dioxide utilization technology in China was relatively low, and the key differences of low carbon performance mainly came from two aspects: technical characteristics and carbon neutralization effect. Among the existing typical carbon dioxide utilization technologies in China, the technology of hydrogenation of carbon dioxide to methanol and reforming of carbon dioxide and methane to syngas had relatively remarkable low carbon performance. In addition, through the comparative analysis of the low carbon performance in the future, the low carbon performance of different carbon dioxide utilization technologies varied greatly, among which the low carbon performance of carbon dioxide mineralization curing concrete technology and carbon dioxide photoelectric catalytic conversion technology was significantly improved.

The electrocatalytic reduction of carbon dioxide (CO₂) to produce carbon-containing products can effectively relieve the greenhouse effect and energy shortage caused by excessive CO₂. However, the electrocatalytic reduction of CO₂ could form a variety of products simultaneously, and thus catalysts with both high selectivity and catalytic activity is the focus of such researches. This review briefly describes the basic principles of electrocatalytic reduction of CO₂, the formation pathways of different reduction products, the active intermediates, the rate control steps, the active catalysts. The existing problems are also analyzed, and a method to improve the catalytic activity is proposed. The development trend of the catalyst is summarized and the common strategies include manufacturing nanostructured materials, supporting catalysts on carriers with high specific surface areas, heteroatom doping, alloying, and introducing defects. The effects of changing the factors such as electron transport by using these methods on the catalyst activity and selectivity are analyzed.

Electrocatalytic CO₂ reduction to syngas is one of the effective ways to realize CO₂ utilization, but some problems, such as high overpotential, poor selectivity and difficulty in accurately regulating the composition of syngas, still exist in its application. This paper reviews the research progresses of the electrocatalysts for CO₂ reduction to syngas, including metal catalysts, metal complex catalysts, metal oxide and sulfide catalysts, as well as single atom catalysts and non-metallic catalysts. Furthermore, the characteristics of H-type cell, continuous flow cell, solid oxide electrolytic cell and membrane reactor electrolytic cell are introduced. Also, effective strategies to improve the catalytic efficiency of CO₂ electroreduction to syngas are summarized, including anodic reaction coupling, structure design of double-active site catalysts and control of catalysts' hierarchical morphology. Finally, the future development directions of syngas production by CO₂ electroreduction are discussed, including machine learning aided catalyst design, understanding the interfacial electrochemical process with multi-scale simulation and exploring the reaction mechanism using operando characterizations.

Pipeline is the optimal way in transporting large amounts of carbon dioxide (CO₂) in CCUS (carbon capture, utilization and storage) technology industrial chain. In this paper, the research progress on decompression and fracture propagation of CO₂ pipeline leakage was reviewed from aspects of experiment and computer simulation. The influence of phase state, pipe material and buried condition on crack propagation was analyzed. The influence of equation of state (EOS), impurity factor and theoretical model on experimental and simulation calculation were discussed. The EOS suitable for the establishment of decompression wave prediction model was summarized and the theoretical method and simulation software of fluid-structure coupling research, as well as the technical documentations for the design of CO₂ transport pipelines, were mentioned. The scientific problems that need to be studied further in CO₂ pipeline leakage decompression and fracture propagation control were summarized. Prospecting the research contents that need to be carried out include: ①establishing the EOS calculation model of multivariate mixture at three phase point and phase line, ②seting up the coupling relationship between the thermal properties of CO₂ and crack propagation furtherly, ③establishing the stop criterion of pipeline fracture, and ④developing and optimizing the special crack stop devices to avoid fracture propagation for CO₂ transportation pipelines.

Electrochemical reduction of CO₂ to chemicals receives worldwide attention owing to its ambient operation conditions and potentials to utilize distributed renewable energies, and is regarded as an effective strategy for mitigating global warming and energy crisis. Assessment of potential economic and environmental benefits of this novel technology can promote its industrialization. Using the electroreduction of CO₂ to methanol in ionic liquid electrolyte as a case study, a comprehensive model for evaluating its cost and net carbon emissions based on the conceptual design and simulation was established under life cycle framework. A sensitivity analysis was also conducted to identify key cost drivers, such as faradaic efficiency, electricity cost and cell voltage. The results showed compared with the coal-to-methanol process, this novel process had both economic benefit and carbon emission reduction potential. Under the best technical assumptions, it can save cost by around 11.67%. Meanwhile, a negative carbon emission of up to 1.29kg CO₂ per kg methanol produced can be achieved if the process is powered by renewable electricity, providing important references for the development of transformative technologies in low-carbon methanol production.

Ostwald ripening behavior widely exists in bubbles in porous media. In order to explore the ripening characteristics of bubbles in porous media, air was used as the simulation gas to study the ripening process of double porosity and four porosity bubbles through visualization experiment and numerical calculation, and the influence of heterogeneity of porous media on the ripening process was explained. The results showed that although the double porosity gas saturation was small, the forward ripening also occurred. However, due to the existence of pore structure, the ripening rate was obviously lower than that of free fluid. The four porosity study showed that the heterogeneity of porous media had a significant effect on the bubble ripening process. Due to the geometric constraints of pores, the bubble will undergo reverse Ostwald ripening in some cases, that is, the growing bubble will stop growing and reverse ripening after filling the pore space, resulting in the size reduction. In heterogeneous porous media, due to ripening, bubbles tend to transfer to the macropore area, which led to the enrichment of macrobubbles in the macropore area and the risk of leakage, thus affecting the storage.

Theoretical identification method of flameless combustion was established and validated considering the swirl inlet and CO₂ dilution based on temperature criterion and time criterion. The effects of structural and operational parameters on the combustion mode and flame stability were discussed. The critical oxygen concentration for swirl flameless combustion had an error within 8% compared to those reported in literature. With decreasing oxygen concentration, reducing equivalence ratio, or increasing flow rate, the temperature criterion barely changed, while the time criterion was easier to be satisfied, which was good for flameless combustion. The flame stability was worse for flameless combustion with a lower swirl number. As the height of combustion chamber increased, the temperature criterion was easier to be satisfied, while the time criterion was more difficult to be satisfied and the boundary corresponding to the temperature criterion moved downwards faster, which was good for flameless combustion. As the intersecting surface of combustion chamber decreased, the temperature criterion changed little, while the time criterion was easier to be satisfied, which was good for flameless combustion. As the outlet surface of combustor increased, both the temperature criterion and time criterion were more difficult to be satisfied, while the boundary corresponding to the time criterion moved downwards faster, which was bad for flameless combustion.

Carbon capture and utilization is an effective way to achieve the carbon reduction target. Gas absorption by alkaline solution on membrane can store CO₂ in the form of \mathrm{H}\mathrm{C}{\mathrm{O}}_{\mathrm{3}}^{-} and \mathrm{C}{\mathrm{O}}_{\mathrm{3}}^{\mathrm{2}-}, and the solution can be further used to convert the absorbed CO₂ into clean fuels. The structure and mass transfer characteristics of PTFE, PVDF, PP membranes in the membrane absorption of CO₂ by NaOH solution were investigated by single-sided membrane immersion and mass transfer experiments. The results showed that the swelling rates of PTFE and PP membranes in NaOH solution increased, and their pore size, porosity, hydrophobicity and mass transfer coefficient decreased. The mass transfer coefficient of PVDF membrane system was close to that of absorption without membrane, which could be attributed to the reaction between the membrane and NaOH solution, causing the structure damage and inability to function as the phase-interface.

Based on the eggshell waste discarded in the food industry, three kinds of organic calcium adsorbents, including calcium acetate, calcium citrate and calcium gluconate, were prepared using the corresponding organic acids. Their cyclic CO₂ capture performance and carbonation characteristics were studied on a tailored dual temperature tubular reactor and thermogravimetric analyzer, respectively. Furthermore, variation of the crystalline phases, structural characteristic and microscopic morphology of the prepared CaO adsorbents over the cyclic CO₂ capture process were analyzed. The results indicated that the CaO adsorbent derived from calcium gluconate owned highest reactivity and the most pronounced CO₂ capture performance with the first carbonation conversion reaching as high as 85.33%, but it also had smaller crystalline grains of CaO than other absorbents with more developed pores within 20—100nm. After the twenty CO₂ capture cycles, the neighboring CaO particles involved were found to melt and agglomerate into larger particles, which resulted in loss of the pore structure and reduced porosity, and thereby its carbon capture performance decayed.

The excessive emission of greenhouse gas CO₂ has caused global climate change. Catalytic conversion of CO₂via hydrogenation is a promising route for the achievement of carbon circular economy and carbon neutralization target. In this study, the bio-SAPO-34 with multiple meso- and macro- structures was synthesized by using rice husk as the bio-template. The hierarchical structure of bio-SAPO-34 facilitated the diffusion of reaction intermediates and improved the catalytic activity. The effect of synthesis parameters such as precursor concentration, structure-directing agent and the amount of rice husks on the replication the architecture of rice husks biotemplate have been systematically studied. Moreover, the ZnZrO _x was composited with bio-SAPO-34 to form ZnZrO _x &bio-SAPO-34 bifunctional catalyst for CO₂ hydrogenation to light olefins. Under reaction conditions of 380℃ and 3MPa, the selectivity of low olefins was 66.4% (in hydrocarbon products) with a CO₂ conversion of 11.8%. Furthermore, the obtained ZnZrO _x &bio-SAPO-34 bifunctional catalysts showed excellent stability in a 60h long-term test.

We will strive to achieve carbon neutrality by 2060. The fundamental route to achieve carbon neutrality is to transform energy use form from fossil energy to renewable energy. Liquid sunshine is an integrated technology, which utilizing solar energy or other renewable energy to produce green hydrogen from water splitting, then converting CO₂ with green hydrogen into methanol. It is not only a new energy storage form for renewable energy, but also an effective way to solve the problem of rigid CO₂ emissions from industry, such as metallurgy, and building materials, chemical industry. In this paper, the latest research progress of liquid sunshine is summarized, including two key technologies: hydrogen production from water splitting and CO₂ hydrogenation to methanol. Finally, the industrial application of liquid sunshine technology is briefly introduced.

As an important renewable biofuel, the use of bioethanol can greatly reduce greenhouse gas emissions. In order to establish a more efficient and low-energy bioethanol recovery process, in situ separation (ISPR) technology came into being. This paper reviews the research progress of ISPR technology of ethanol in recent years, and introduces the principle and application in detail, including gas stripping, vacuum fermentation, adsorption, liquid-liquid extraction, pervaporation, membrane distillation and other separation technologies. Aiming at the problems of separation performance, energy consumption and cost, this paper analyzes the advantages and disadvantages of different separation technologies coupled with fermentation process. Meanwhile, this paper focuses on the membrane separation technology represented by pervaporation, and summarizes the selection of membrane materials and the preparation methods of membrane, in order to improve the performance of ethanol separation membrane and optimize ethanol separation process. Furthermore, to integrate the characteristics and advantages of different separation technologies, focusing on the development of multi-stage coupling separation system, the performance and potential for the combination of separation technologies are evaluated, to which the development prospect is judged on this basis.

With the rise of new energy industry in various countries, hydrogen energy has become the most potential renewable energy. Catalytic reforming of bio-oil is an excellent and efficient method for hydrogen production and it broadens the way of high-value utilization of bio-oil. This article reviews the related research in this field in recent years, focusing on the effects of raw materials on the reforming reaction (different sources of bio-oil and its models), the effects of catalyst characteristics on the reforming reaction (loaded precious and non-precious metals), and the effects of operating conditions on the reforming reaction. The microwave catalytic reforming technology is briefly introduced. In view of the difficulties faced in this field, some prospects and development directions are put forward, which provides an important theoretical basis for the field of hydrogen production by catalytic reforming of bio-oil.

Due to the component diversity of aqueous bio-oil, it faces the problems of uneven component gasification and low conversion efficiency of raw materials in the process of catalytic reforming for hydrogen production. In this study, the feeding system was optimized to make the aqueous bio-oil instantaneously vaporized in the reaction tube. On this basis, a set of catalytic reforming hydrogen production device integrating fixed bed and fluidized bed was designed and processed. A series of experiments were carried out to explore the conversion efficiency and hydrogen production effect of aqueous bio-oil in two reactors by in-situ gasification strategy. The results showed that the conversion efficiency of aqueous bio-oil in fluidized bed (about 95%) was significantly higher than that in fixed bed (about 80%), and the H₂ selectivity in both reaction systems could remain stable at 100% for a long time. The obvious deactivation of catalyst by carbon deposition occurred in the later stage (about 100min) of the fixed bed reaction system, while in the fluidized bed, the catalysts always maintained high activity without carbon deposition. Their liquid products were analyzed, and all the components of aqueous bio-oil were nearly completely transformed in fluidized bed, while a small amount of acetic acid and phenol remained for fixed bed and some ketones (acetone, etc.) were generated at the same time. These results prove that the in-situ gasification strategy greatly promotes the total component transformation of aqueous bio-oil. Combined with the fluidization effect of catalyst in fluidized bed, which can greatly enhance the catalytic conversion efficiency and stability, it will greatly promote the industrial chain process from biomass to bio-oil to hydrogen.

In recent years, deep eutectic solvent (DES) has attracted extensive attention in biomass pretreatment owing to its advantages of easy preparation, low cost and easy recovery. In this study, DES was synthesized with choline chloride as hydrogen bond receptor and ethanolamine as hydrogen bond donor. The effects of pretreatment conditions of different temperature, time and solid-liquid ratio on the components and enzymatic hydrolysis of herb residue were studied. The results showed that, the lignin removal rate was 78.42% and the cellulose recovery rate was 83.89% after pretreatment at 120℃ for 4 hours with the solid-liquid ratio of 1∶20. After 96 hours of enzymatic hydrolysis, it was found that the enzymatic hydrolysis efficiency of the substrate under the optimal conditions was 78.57%, which was 1.58 times higher than that of untreated herb residue(30.40%). Fractal like kinetic analysis showed that the pretreatment temperature had the greatest impact on the enzymatic hydrolysis effect. SEM, XRD and FTIR analysis showed that the changes of substrate morphology, crystallization index and functional group after pretreatment were conducive to the improvement of enzymatic hydrolysis effect.

Bamboo shell (BS) was pretreated by ultra-high pressure (UHP), alkaline-heating method (AH), UHP combined with AH (UHP+AH) and AH combined with UHP (AH+UHP). The chemical composition was determined. And scanning electron microscopy (SEM), crystal structure (XRD), infrared spectroscopy (FTIR), specific surface area and pore structure, and enzymatic hydrolysis were used to analyze the changes of samples before and after pretreatment. The results showed that AT+UHP pretreatment had the best effect under 450MPa pressure compared with other pretreatment methods. After pretreatment with AT+UHP at 450MPa, 86.87% of the lignin was removed, the surface was loose and coarse, and the crystallization index increased, the specific surface area and pore size were 2.590m²/g and 0.010cm³/g, respectively, while the enzymatic hydrolysis efficiency was 97.89%. There was no obvious difference between the pretreatment effects of UHP+AT and AT+UHP. The enzymatic hydrolysis efficiency of UHP+AT pretreatment sample was up to 96.94%. Therefore, alkaline combined with ultra-high pressure pretreatment can be a potential alternative for biomass pretreatment in biofuel production.

In 2019, CO₂ emissions of China were 2.11 billion tons, accounting for 21% of the total emissions. Under the goal of China's 2060 carbon neutral goal, petrochemical industry needs technology innovation. This article discussed the petrochemical industry carbon neutral policies and measures at home and abroad and analyzed the petrochemical industry’s carbon neutral technology path from three aspects: carbon-reduction emission, carbon-zero emission and carbon-negative emission. Carbon-reduction emission technology includes green oil/gas development, process low-carbon utilization, and coordinated technologies for pollution and carbon reduction. Carbon-zero emission technology includes renewable energy and nuclear power generation, green hydrogen, and zero-carbon materials/fuel substitution such as biomass to gasoline and diesel, aromatics and other bulk energy chemical technologies. Carbon-negative emission technology includes bioenergy with carbon capture and storage (BECCS) and the technology of CO₂ conversion to fuel chemicals. Besides, some carbon neutral information technologies such as artificial intelligence, big data and internet of things were introduced. This article would provide technical references of carbon neutral path for petrochemical industry.

Carbon emissions from industrial processes account for up to 70% in China. Energy saving and efficiency enhancement, clean fuels, CO₂ capture, etc. are the key pathway to achieve carbon emission reduction in industrial processes. High-efficient membrane separation has been deemed as a generic technology for energy saving, emission reduction and environmental protection. Focusing on carbon emission reduction, this paper summarized the main research progress in our group including organic solvent dehydration, clean fuel production, CO₂ separation, and chemical reaction intensification using zeolite membranes. Based on the more than ten years of experience on organic solvent dehydration, we proposed hollow fiber zeolite membranes for lower investment and membrane process optimization, which would be the key point for large-scale application. Since there is no practical application for industrial gas separation, it is highly desired to strengthen the preparation of high-/all-silica zeolite membranes and the separation of complex gas mixture. This would prove the way of zeolite membrane to practical application for gas separation.

The carbon neutrality goal set by Chinese government in 2060 poses very strong constrains to the Chinese iron and steel industry on the one hand, and also provides a very good opportunity for the industry to compete with foreign counterparts on the other hand. In the present paper, the development history and technical status were analyzed for green hydrogen direct reduction, molten oxide electrolysis, electrowinning of iron in alkaline solution and electrowinning of iron in acid solution, etc. Under the scenario of sufficient low-cost green electricity, the theoretical and practical electricity consumption were evaluated for these routes together with the analyses about technique maturity, electricity consumption, technical difficulty and application prospect, etc. Through the analyses, it was found that the alkaline solution electrowinning of iron demonstrated the lowest electricity consumption, followed by the acid solution electrowinning of iron and the hydrogen smelting reduction with endothermic reaction heat provided by electricity. From technical point of view, the acid solution electrowinning of iron and the hydrogen direct reduction routes, both had completed pilot plant operation, were among the easiest to be implemented, while the hydrogen smelting reduction, alkaline solution electrowinning and the molten oxide electrolysis routes were still in the early stage of development. By the analyses, it was concluded that the acid solution electrowinning, the hydrogen direct reduction and the hydrogen smelting reduction routes were quite promising, while the molten oxide electrolysis and alkaline solution electrowinning were too challenging to be usable in 2060.

The implementation of carbon neutralization target will have a profound impact on the development of coal chemical industry and technology in China. This paper analyzes the overall CO₂ emission of coal consumption and coal chemical industry and the role of coal chemical industry in the national economy, proposes that the coupling of carbon emission reduction technology and coal chemical process is the key to realize the carbon emission reduction and sustainable development of coal chemical industry and realistically choosing measures to optimize industrial structure and improve energy efficiency can significantly but limited reduce CO₂ emission. In order to achieve CO₂ emission reduction in 100 million ton scale, these technologies of green electricity and green hydrogen, CCS/CCUS and CO₂ resource utilization must be adopted. The paper reviews the main progress on the technologies of green electricity and green hydrogen, CCS/CCUS and CO₂ resource utilization in recent years, and points out that in the 10 years before the carbon peak in 2030, these carbon emission reduction technologies will be in the key demonstration test period. Whether they are mature and reliable will determine the development trend of coal chemical industry after the carbon peak. It is predicted that the demonstration application of hydrogen metallurgy and green ammonia synthesis will possibly lead to significant changes in the structure of coal chemical industry. Finally, the paper prospects and outlines the possible zero carbon chemical industry system based on the research progress of air direct capture CO₂ technology and photo/electro-catalytic CO₂ conversion or simulated photosynthetic reaction via CO₂ and water.

Since the discovery of highly selective and efficient hexagonal boron nitride(h-BN) in 2016 as the catalyst for oxidative dehydrogenation of propane(ODHP) to propene, the boron-based materials have aroused significant research interests. Unlike traditional metal and transition metal oxide-based ODHP catalysts, the metal-free boron-based materials exhibit high industrial prospects due to their low overoxidation, high olefin productivity and environmental friendliness. In this review, the characteristics of different boron-based catalysts have been systematically discussed from the aspects of catalyst design, synthesis strategy and ODHP performance. Meanwhile, the reaction mechanisms are elaborated based on the potential reaction routes, key intermediates, rate-determining step as well as the catalytic kinetics behaviors, which could provide a comprehensive and insightful understanding of the active sites and structure-activity relationship of boron-based catalysts. It is recognized that the effective construction of the tri-coordination B-O/B-OH active sites and the realization of the synergistic catalysis of the surface and gas radical reactions are the key to improve the performance of propane dehydrogenation over boron-based catalysts. Based on the current researches and existing problems, the future development and industrial application of boron-based catalyst systems are prospected.

Alkylated oil is the key blending component for the quality upgrade of the Ⅵ gasoline, and its market demand and production capacity in China continue to increase. The quality of alkylation products and the cleanliness of the production process are the keys of alkylation development. This paper reviews the current status of treatment technology of sulfuric acid alkylation effluent. It briefly describes the traditional wet treatment STARCTCO process by acid washing, alkaline washing and water washing, and highlights the engineering development and successful application of fiber reinforced coalescence separation technology in domestic SINOALKY process. Based on the experimental research and the sideline test, the multi-stage fine coalescence dry treatment technology was developed. The application of dry deacidification in refining system significantly reduces the energy consumption and related environmental pollution, and hence contributes to the green and low-carbon development of alkylation technology in China.

Electromagnetic induction heating (EIH) is a non-contacting heating technology that directly absorbs and converts electromagnetic energy into heat. Heat is rapidly induced on magnetic materials without the need to heat the whole reactor, which improves energy transfer efficiency and reduces heat dissipation. Therefore, EIH provides a unique solution for high-temperature chemical processes of slow heating / cooling rate, uneven heating and low energy efficiency. This article briefly described the heating mechanism and related measurement methods of EIH, focusing on the energy efficiency evaluation. Then we summarized the research advances of EIH for high-temperature catalytic reactions. Finally, the prospect of the industrialization of EIH in the future was put forward.

Plastics play an important role in social and economic development, while their mass production and inappropriate disposal have caused serious ecological disasters. The transformation of waste plastics into value-added products through chemical recycling and upcycling is one of the key technologies to achieve sustainable development of plastic resources. This review comprehensively summarizes recent progress in waste plastic valorization by various methods (e.?g., catalytic pyrolysis, solvolysis, hydrogenolysis, photocatalysis, chemical oxidation, etc.), focusing on discussing the effects of reaction conditions on product distribution and yields, structure-activity relationships, and reaction mechanisms. In view of the existing problems such as harsh reaction conditions, high catalyst cost and low reuse ability, future research directions are proposed, including optimization of process conditions, clarification of catalyst deactivation mechanism and development of inexpensive and efficient catalysts, which are expected to realize the industrial development of plastic resource utilization.

The growing demand towards plastic products for human production and life contributes to a huge increase in plastic waste. The consequent environmental crisis and social problems have become a serious issue that urgently need to be addressed. This paper reviews the development of plastic waste recycling by pyrolysis at home and abroad under the background of carbon neutrality. The technology advancement of plastic waste pyrolysis is summarized including catalyst, reactor and co-pyrolysis with other waste solid. The progress of plastic recycling companies and oil companies is concluded, including production of fuel oil and production of chemicals. The significance of resource-saving effect, carbon emission reduction and economic benefits of plastic waste recycling is elucidated. It is pointed out that there still exist some problems in domestic plastic waste recycling by pyrolysis such as lack of regulations, unclear classification of waste plastics, imperfect industrial chain and lack of in-depth academic research. It is advised that domestic oil companies should recycle waste plastics from the perspective of the whole life cycle. Combined with the upstream and downstream industrial chain, the oil production route and chemical production route of waste plastic pyrolysis should be implemented in stages.

China's industrial by-product gas emissions is large, which makes pollution to the environment, and meanwhile wastes the valuable resources such as H₂ and CO. Hydrogen is an important chemical raw material, and also is a carbon-free and high-efficiency energy. The separation and purification of hydrogen from industrial by-product gas could reduce resources waste and CO₂ emission. This article introduces the current emissions status of hydrogen-containing industrial by-product gas in China, three typical industrial hydrogen production processes, the calculation and analyses of their costs and CO₂ emissions. These three typical processes are hydrogen production from Coke Oven Gas, refinery gas, and chlor-alkali emission gas. Taking into account factors such as carbon dioxide emissions and carbon transaction costs, the comprehensive cost advantage of hydrogen production from industrial by-product gas is more competitive. In the context of carbon neutrality, hydrogen production from industrial by-product gas is an effective and feasible way to obtain low-carbon hydrogen energy. Further researches and development of industrial by-product gas hydrogen production technologies would provide an efficient way to reduce carbon emissions.

Vigorously developing hydrogen energy is an important way to achieve the goal of "carbon peak and carbon neutrality". Mixing hydrogen gas into existing natural gas grids is conducive to the economical, efficient and large-scale transportation and application of hydrogen energy. Appropriate hydrogen mixing ratio is one of the key problems to be solved in hydrogen-mixed natural gas pipeline system. It is said that when the ratio of hydrogen mixing into natural gas is below 10%, it can be transported directly through the natural gas grids without verification. However, this view is untenable at present. The reasons were expounded in this paper from three aspects: adaptability of pipe network system to hydrogen mixing, discussion on hydrogen mixing ratio of demonstration project, and standard specification. Pipeline transportation technology of hydrogen-mixed natural gas was in its initial stage and its safety guarantee still faced many challenges. Any conclusion needed to be demonstrated and verified repeatedly in order to steadily promote the development of hydrogen energy.

Industrial kiln co-processing solid waste technology is an effective way to scientifically dispose of solid waste. The high temperature environment of industrial kilns is conducive to the thorough transformation and decomposition of solid waste, and effectively controls secondary pollution such as dioxins and heavy metals. At the same time, it can save the investment and operating costs of special solid waste disposal facilities and replace part of the fossil fuels or production raw materials needed for industrial production. In this paper, the co-processing technology of solid waste in industrial kilns, such as cement kilns, steel smelting kilns, coal-fired boilers in power plants and coal-water slurry gasifiers, are introduced. The technical research and engineering application status of co-processing solid waste in industrial kilns is reviewed. Combining the properties of solid waste and the characteristics of industrial kilns in various industries, the applicability of solid waste is analyzed. Comparing the common non-heat treatment technology of solid waste and heat treatment technology of solid waste, it is pointed out that the industrial kiln co-processing solid waste technology had the advantages of high potential of solid waste elimination, high level of resource utilization, good environmental benefits and no neighbor avoidance effect. Finally, the future development of the field of solid waste co-processing is prospected. The industry standards, technical specifications, laws and regulations for the co-processing of solid waste in cement kilns are becoming mature, while there is still more technology optimization space and development potential in the co-processing of solid waste technology in steel smelting kilns, coal-fired boilers in power plants and coal-water slurry gasifiers.

Under the background of "carbon neutralization", sludge treatment and disposal is an important field of emission reduction. Anaerobic digestion is one of the key technologies of sludge safety disposal and energy recovery. As a low-carbon technology, the carbon emission of anaerobic digestion is mainly the result of the balance between the "energy source carbon emission" produced by energy consumption in the process of treatment and the "carbon compensation" formed by biomass energy (such as methane) produced after treatment and disposal. Therefore, reducing energy consumption and improving methane production are the main ideas to realize "carbon neutralization". Thermal, chemical, and mechanical pretreatment are effective means to break the rate-limiting hydrolysis of anaerobic digestion, mainly focusing on increasing methane production to form more "carbon compensation". However, from the perspective of thermodynamics, pretreatment is the process of dissolving a large amount of organic matter through the consumption of electric, heat, and chemical energy, thereby obtaining more biomass energy. As an energy input form, pretreatment increases the energy consumption of anaerobic digestion. The inhibitory factors produced in the process prevent the solubilized organic matter from being completely converted into methane. Increasing methane production is usually difficult to balance this part of the energy consumption. Therefore, the selection of low energy consumption pretreatment methods can effectively reduce carbon emissions. Previous studies usually used methane production as the evaluation index of anaerobic digestion performance, which was difficult to objectively evaluate the actual benefits of various anaerobic digestion pretreatments. In this paper, the mechanism of various sludge pretreatment methods and their inhibitory factors on anaerobic digestion were reviewed. The research results of typical thermal pretreatment, alkali pretreatment, ultrasonic pretreatment and combined treatment on methane production, net energy and net profit were compared. Based on the evaluation of anaerobic digestion efficiency of sludge, the feasibility of the above pretreatment methods at the energy and economic levels was analyzed, which provides multi-dimensional basis for the selection of pretreatment methods and intensity.

HNCERI (Huaneng Clean Energy Research Institute) two-stage dry powder pressurized gasifier was used was the research object. A random pore model that considers the effect of gas diffusion on the surface of char particle was used to calculate the char gasification reactions rate to evaluate carbon conversion efficiency. The slag sub-model was used to calculate the slag distribution characteristics and the wall heat loss of the first stage. The effect of coal size on carbon conversion efficiency and the slag distribution characteristics in HNCERI gasifier were studied. The results showed that the model can accurately predict the main gas components at the outlet of the gasifier, the carbon conversion efficiency and the wall heat loss. The carbon conversion efficiency of the first stage was mainly controlled by the intrinsic gasification reaction rate and the particle residence time, while the second stage carbon conversion efficiency was mainly controlled by particle residence time. Therefore, the decrease of coal size which significantly reduces the gas diffusion resistance on the surface of char particles was beneficial to increase carbon conversion efficiency of the first stage, while the appropriate increase of coal size which is conducive to increase the particle residence time was beneficial to increase the carbon conversion efficiency of the second stage. The simulation results showed that when the particle size increased from 20μm to 200μm, the first-stage carbon conversion efficiency decreased from 99.68% to 95.06%, while the second-stage carbon conversion rate increases from 69.03% to 89%. The coal size had little effect on the liquid slag distribution on the neck and straight wall of the gasifier, but had significantly effect on the development of solid slag layer.

A bubble column carbonation reactor was set up. The CO₂ mineralization capacity through the direct aqueous carbonation of carbide slag under ambient temperature and atmospheric pressure was evaluated. The effects of the important operating parameters, including the superficial gas velocity, liquid to solid ratio and CO₂ concentration, on the capacity of CO₂ mineral carbonation and carbonation efficiency of carbide slag were revealed. The response surface model was built to analyze the effects of the operating parameters and to obtain the maximum of the carbonation efficiency. The results indicated that the increase in the gas velocity was beneficial to the calcium ion dissolution and CO₂ absorption, but it will have the gas channeling effect in the reactor when the gas velocity was high, which has an effect on the solid-liquid mass transfer and reduces the carbonation efficiency. When the liquid to solid ratio reduced, the concentration of calcium ions rose, which was good for the carbonation reactions. However, when the liquid to solid ratio was very small, it was disadvantageous for the solid-liquid mass transfer. Proper increase in the CO₂ concentration was beneficial to enhance the carbonation efficiency. When the CO₂ concentration increased to a certain level, it had a rare effect on the carbonation efficiency. According to the response surface modeling, the impact degree on the carbonation efficiency ranged as liquid-solid ratio > CO₂ concentration > superficial gas velocity. The optimization carbonation efficiency was 93.58% found by the response surface optimization, and the corresponding superficial gas velocity was 0.07m/s, the liquid-solid ratio 8.26mL/g and the CO₂ concentration was 20.91%. Therefore, the results showed that it had a good CO₂ mineralization capacity and a high carbonation efficiency for the direct aqueous carbonation of carbide slag under ambient temperature and pressure in a bubble column. This study provides the theoretical data for CO₂ capture by aqueous mineral carbonation of carbide slag. Accelerated carbonation of carbide slag in the bubble column is a promising process for CO₂ capture due to its higher carbonation conversion of carbide slag within a shorter reaction time.

Proton exchange membrane fuel cell (PEMFC) has been considered as one of the most promising next-generation power sources for clean automobiles because of their advantages in efficiency, power density, environmental friendliness, low temperature start ability, etc.. However, the gap between the durability and cost of PEMFC and those of commercialization requirements is still large. To overcome the above-mentioned two major problems, joint efforts and progress of the entire fuel cell process chain are required. In this paper, the recent research progress of the entire PEMFC process chain, from catalysts, membrane electrode assemblies (MEA), fuel cell stacks to fuel cell engines, are analyzed and classified reviewed, and research hotspots such as single-atom catalysts, non-noble metal catalysts, special morphology catalysts, ordered catalyst layers, high-temperature proton exchange membranes, MEA interlayer interface optimization, integrated porous bipolar plates, hydrogen circulation, are introduced. This paper points out that low/non-platinum catalyst layers, ultra-thin proton exchange membranes, gradient/ordered MEA, high-temperature operation and self-humidification of fuel cells are the future development trends, of which further innovation and breakthrough are urgently needed.

Water splitting by alkaline electrolysis for hydrogen production has gained considerable attention in recent years due to its merits of low cost, environmental friendliness and available intermittent power from PV and wind farm. As the core components, ion-conducting membranes have crucial effects on the performance, durability and safety of the electrolyzers. Therefore, it is of great significance to develop ion-conducting membranes with good hydroxide ion conductivity, highly alkaline stability and low hydrogen permeability. This paper reviews the latest research progress in porous separation membranes, ion-solvation membranes and anion exchange membranes. Moreover, the research progress and technical problems of ion-conducting membranes used in alkaline water electrolysis were analyzed from the perspectives of hydroxide conductivity, alkali resistance stability and electrolysis performance. New ideas for the design and synthesis of next-generation high-performance membranes are also proposed.

Membrane with both high ion selectivity and conductivity is crucial to the new energy battery technologies (such as flow batteries, fuel cells, lithium batteries). In recent years, researchers have proposed to construct porous ion conductive membranes to break the trade-off effect between ion selectivity and ion conductivity. This review briefly summarizes the latest research progress of porous ion conductive membranes as battery membranes from three aspects of inorganic, organic and composite porous ion conductive membranes, and summarizes the advances of porous ion conductive membranes in new energy batteries such as flow batteries, fuel cells and lithium batteries. Finally, this review points out that the future research of porous ion conductive membranes should focus on the adjustment of porous membrane structure, the development of high-performance porous membrane materials, and the application of porous membranes in novel battery systems.

Functional hydrogels, which are soft and wet materials containing three-dimensional polymeric networks with flexibly tunable functions and properties, provide ideal materials for developing high-perfromance soft supercapacitors. This review summarizes recent progress of functional hydrogel materials for soft supercapacitors with emphasis on the introduction of the design, fabrication and performance enhancement of soft supercapacitors for electrochemical double-layer capacitors and pseudocapacitors. Strategies for enhancing the electrochemical and mechanical properties of supercapacitors are discussed via designing the composition and structures of hydrogels and regulating their performances. Meanwhile, the important roles of the compositional and structural design of hydrogels and their performance regulation in the achievement of function diversity such as self-healing and high anti-freezing properties are analyzed. In the final part, the prospects on the future development of functional-hydrogel-based soft supercapacitors towards the ones with properties such as high energy storage, high flexibility, high water-retention, self-healing, high cold-tolerance and degradability are provided.

Thermal management system is essential for power batteries to ensure their optimal operation temperature range of 20—50℃. Phase change materials (PCM) can absorb or release a lot of heat while keep the temperature unchanged by phase change, and have been widely used in battery thermal management. This paper reviews the research progress of battery thermal management systems based on phase change heat storage technology, mainly introducing the passive thermal management system, active thermal management system, and thermal management system coupled with active heat dissipation and phase change. As a result, composite PCMs have good shape stability, high thermal conductivity that can effectively reduce the temperature of the battery pack and improve the temperature uniformity. The capability of electro-thermal conversion of conductive composite PCM allows it to be used to preheat the battery at a low temperature so that the PCM can have both the heating and cooling functions. However, in the passive thermal management system, the heat absorbed by PCM cannot be released in time, and the heat accumulation will lead to system failure. The thermal management system coupled with active heat dissipation and PCM has better temperature control performance, stability and security. Phase change emulsion has the advantages of large specific heat capacity and phase change, and can replace water as the cooling medium of battery thermal management system to obtain better temperature uniformity and lower power consumption. However, the problems such as poor stability and high-degree undercooling of phase change emulsion still need to be overcome. In conclusion, the battery needs effective temperature control at both high and low temperatures, and the design of battery thermal management working in the full temperature-range deserves further research.

The application of proton exchange membrane fuel cell (PEMFC) in combined cooling, heating and power (CCHP) system can improve the system efficiency effectively and realize the sustainable development of CCHP. In this paper, the research progress in mathematical modeling, operation strategy, energy management, multi-dimensional evaluation, system optimization theory and application of the CCHP system based on PEMFC was introduced. The limitations of current research in energy endowment, supply and demand integration, multi-scale modeling, multi-energy complementary energy supply, evaluation system, system integration and optimization and so on are summarized. The future development of CCHP system can be carried out from aspects of multi-scale modeling, deep integration of source, network, load and storage, improving evaluation system, system optimization and real-time regulation, which provide some new ideas for a more comprehensive and stable CCHP system based on PEMFC.

China has put forward the ambitious goal of "carbon peak by 2030 and carbon neutral by 2060" in order to cope with global climate change. Under the dual carbon target, China's energy structure will transform from the traditional fossil energy to the renewable energy. The transformation of energy structure changes the connotation and evaluation methodology of energy security. The quantitative evaluation methods of energy security are summarized. The advantages and disadvantages of these quantitative methods are analyzed and the scope of their application is marked. The evaluation methods based on energy supply security and national and regional energy security are elaborated. Under the dual carbon target, the parameter of energy security index is different from the previous evaluation index of fossil energy supply security. In parameter selection, more attention is paid to environmental indicators such as emissions of carbon dioxide, sulfur dioxide and particulate matter, and related water and food are also included in the quantitative evaluation system of energy security as important evaluation indicators. Under the dual carbon target, especially during the transition period of energy structure transformation, it is of great practical significance to establish a reasonable quantitative evaluation system of energy security.

The new chemical materials are an important part of new materials and the key materials required for national economic construction. The development of new chemical materials has become an important direction for the transformation and upgrading of the refining and chemical industry. The industrial development status of new chemical materials at home and abroad was analyzed in this paper, focusing on the carbon sequestration of renewable raw materials and typical new materials (including high-end carbon materials, automobile lightweight materials, new energy materials and carbon capture materials) from the perspective of the whole life cycle (LCA) of raw material supply, new material production, product recovery and recycling of new chemical materials carbon sequestration in production and carbon reduction in waste material recovery and recycling. The development status and prospect of China's new material industry were analyzed. It was considered that new chemical materials had a significant effect in reducing CO₂ emission and realizing the goal of carbon neutralization. Based on the strong demand of China's new chemical material market, China should increase investment in technology R & D and make breakthroughs technological bottlenecks, accelerate the industrialization of independent products, meet the urgent needs of China's economic development and promote the green, low-carbon and high-quality development of social economy.

How to achieve the goal of building a modern socialist country in an all-round way and achieving carbon neutrality by 2060 is a necessary question for the future development of manufacturing industry. Pushing energy intensive and highly polluting manufacturing enterprises to "green manufacture" is a key step to achieve the goal of peak carbon dioxide emission and carbon neutrality. The current situation of carbon emission in manufacturing industry from accounting methods, macro indicators, industry distribution and energy structure were summarized and analyzed in this study. And then, the common carbon emission reduction countermeasures and low-carbon technology in key industries of manufacturing industry were introduced. Finally, the relevant commercial applications were listed and the technical development bottlenecks were explained. Common mitigation strategies for manufacturing were source reduction, clean energy using, carbon capture, utilization and storage, and the industrial internet. Low-carbon production technology in the key industries mainly included direct reduction of hydrogen to produce iron and steel, hydrogenation of carbon dioxide to methanol, biomass to bio-oil, etc. Iron and steel, chemical industry, building materials, petrochemical and coking, non-ferrous metal smelting as the important parts for manufacture, should contribute to the goal of carbon neutrality by choosing mitigation strategies adapted to their own production processes.

The consistently high dependency on importing ethylene glycol and the resource characteristics of rich coal and less oil of China make coal-to-ethylene glycol technology have better cost and raw material advantages and develop rapidly. The present situation and development trend of coal-to-ethylene glycol technology at home and abroad are summarized, and the technical characteristics, flowsheet and technological progress of key unit technologies such as coal gasification, dimethyl oxalate synthesis and ethylene glycol synthesis and refining units are emphatically introduced. The influence of the relevant units on the technical and economic performance of the whole coal-to-ethylene glycol system is analyzed. Aiming at the problems of high energy consumption, low mass and energy efficiency and large CO₂ emission in the existing technology of coal-to-ethylene glycol, it focuses on the development of the novel process for the production of ethylene glycol from coal and hydrogen-rich resources that integrates the efficient utilization of CO₂, including the novel processes that couple with coke oven gas, shale gas and green hydrogen resources. Taking coke oven gas as an example, compared with the traditional process, the novel processes integrating different reforming technologies can improve carbon efficiency and exergy efficiency by 23.35%—39.17% and 4.25%—10.12%, reduce production cost by 8.73%—19.88%, and increase internal rate of return by 3.6%—9.6%, respectively. Therefore, the coal to ethylene glycol process integrated with the effective utilization of coke oven gas, shale gas and green hydrogen is the promising direction for the efficient, economic, and clean development of this industry.

With the increasing demand for energy in various countries around the world, new types of energy are urgently needed to supplement the supply of conventional fossil fuels. Natural gas hydrate may become the main alternative energy source in the future due to its wide distribution and high energy density. Compared with traditional mining methods, CO₂ replacement mining can store the greenhouse gas CO₂ on the seabed, and the environmental benefits are more obvious; secondly, and for a natural gas hydrate offshore mining platform, the use of economical and reasonable energy equipment operation schemes can effectively reduce operating cost and improves economic benefits. Nowadays, with the continuous development of offshore wind power, the introduction of offshore wind power into the energy system of offshore platforms has attracted more and more attention. This paper took the energy system of a natural gas hydrate mining platform coupled with a methane reformer as an example. And the lowest total annual cost was set as the objective function to establish a new energy system optimization model under the consideration with and without wind energy access. The commercial solver GUROBI is used to solve the problem. After solving the problem, the best equipment operation plan can be found, and a detailed analysis of the energy system operation plan with wind energy access was conducted. The results showed that the total annual cost of the system after connecting to wind energy was reduced by 21.92%, and the consumption of natural gas was reduced by 35.41%. In addition, through sensitivity analysis, it was found that the optimal proportion of wind energy was affected by the price of natural gas. Based on the price of natural gas currently, the optimal proportion of wind energy was 49.56%. As the price of natural gas increased, the proportion of wind energy gradually increased.

Production of SNG from a waste incineration power plant-power to gas hybrid system can reduce greenhouse gas emissions and storage renewable energy on a massive scale. However, an optimization of this process is still needed due to the low efficiencies of waste incineration power plants and poor waste heat utilization. In this paper, an integrated process was modeled by using Aspen Plus software. Based on energy balance analysis, an innovative way was proposed to improve the efficiency of a waste incineration power plant by recovering the methanation reaction heat. A two-stage methanation process was designed where an adiabatic fixed bed reactor and a low-temperature fluidized bed reactor connected in series. Energy recovered from the hot gas flow at the outlet of the fixed bed reactor was used to improve steam parameters and optimize the steam cycle, and the power generation efficiency was increased from 22.05% to 31.72%. The low-temperature fluidized bed reactor ensured the quality of synthetic natural gas. Moreover, the type of flue gas recirculation in the waste oxy-combustion process had an impact on the overall process efficiency. And the energy conversion efficiency was higher with dry flue gas recirculation. The above results have some guidance for improving process economy and competitiveness.