The chemical looping reforming reaction of methane (CLRM) employs a solid oxygen carrier material as an intermediate to split the traditional methane reforming reaction into two reactions, reduction and oxidation, in which the oxygen carrier is continuously oxidized and reduced, forming a cyclic reaction and realizing the continuous production of syngas or hydrogen. More importantly, the CLRM reaction delivers a high purity product without the requirement of a costly air separation unit compared to conventional reforming reactions. And the key to the research of CLRM reaction lies on the design and selection of oxygen carriers. This paper summarized the recent research progress of metal-based oxygen carriers (Ni, Fe, Cu, Co, Mn, Ce-based) and composite oxygen carriers (including calixarenes and hexaaluminates) in recent years, focusing on the effects of the composition and structure of these oxygen carriers on the reactivity, and concluded the strategy of design and optimization of these oxygen carriers. Furthermore, the methods for the synthesis of the oxygen carriers were summarized and discussed. In addition, the current status of reactor process design was reviewed and potential issues were proposed in terms of the industrialization of CLRM. Finally, some existing challenges and future perspectives on the current studies of oxygen carriers for CLRM reactions were presented.

The development and application of circulating fluidized bed gasification with high-alkaline coal technology was systematically reviewed, with a focus on fundamental physicochemical properties, gasification reaction characteristics, alkali-metal migration behavior, anti-slagging technology research, and industrial demonstration of high-alkaline coal gasification. The characteristics of high-alkaline coal, the distribution and content of alkali metals, the influence of pretreatment methods on sodium content determination, and combustion and ash formation properties of high-alkaline coal were outlined. The effects of coal type, gasification temperature, oxygen-to-carbon molar ratio, reaction atmosphere, and reaction extent on gasification performance of high-alkaline coal and slagging characteristics of gasification residue were summarized. The role and reaction mechanisms of blending coals, additives, and replacing bed materials in preventing slagging during high-alkaline coal gasification were elucidated, leading to stable operation of a pilot-scale circulating fluidized bed gasification of high-alkaline coal by using corundum as bed material. The paper also reviewed the original innovation of circulating fluidized bed gasification of high-alkaline coal and its successful applications in production of industrial fuel gas and syngas. Finally, future directions for high-alkaline coal gasification technology were discussed from four perspectives: establishing a database for high-alkaline coal gasification, developing gasification technologies specifically for pure use of high-alkaline coal, developing efficient alkali removal and in-situ coupling utilization innovation technology, and exploring synergistic utilization techniques of high-alkaline coal with other materials to produce high-performance materials.

The clean and efficient utilization of low rank coal is one of the important strategic needs of China. Among coal thermal conversion technologies, catalytic reforming of coal pyrolysis volatile has high efficiency and wide application prospect. Changing process conditions is an important way to increase pyrolysis conversion and product yield. Optimizing reactor design and developing catalysts with high activity and stability are the important development directions of this technology. This paper firstly introduced the catalytic reforming method of low rank coal and its volatiles, on the basis of which the influence of process parameters such as temperature, atmosphere, and residence time, as well as the strategies and challenges for the application of fixed-bed and fluidized-bed reactors, were reviewed. Then, the modification methods of metal catalysts, carbon-based catalysts and zeolite catalysts and the action principles of their post-treatment and in-situ control were analyzed. The catalytic cracking mechanism of pyrolytic volatiles was summarized. The paper also pointed out the bottlenecks of the catalytic reforming of coal pyrolysis volatiles in industrialized production. The key role of the catalytic conversion path of volatile low carbon hydrocarbons and macromolecular compounds in the directional regulation of secondary reactions during coal pyrolysis was identified, and the influence of acid-catalyzed protonation on the deactivation mechanism of catalysts was deeply explored.

Coal slurry electrolysis for hydrogen production (CSE) is a novel technology that enables electrochemical hydrogen production and the low-carbon clean utilization of coal under mild conditions. The theoretical decomposition voltage of hydrogen production from electrolyzed coal slurry is only 0.21V, and the actual energy consumption is about 1/3—1/2 of that of hydrogen production from electrolyzed water. This method has the advantages of low energy consumption, minimal pollution, and being integrated with the process of separating coal macerals and preparing coal-based fine chemicals. However, the challenges of low coal conversion rate and unclear mechanism of coal slurry electrolysis remain extremely daunting. This review discussed the current status of research on CSE mechanism, outlined the influence of coal rank and minerals on the electrooxidizing activity of CSE, summarized the changing rules of coal surface elements, functional group structure, and coal carbon skeleton structure during CSE in the anode zone, and expound the effects of electrochemical reduction in the cathode zone on the coal surface properties such as coal surface wettability and Zeta potential, as well as hydrogen production by electroreduction with the addition of coal slurry in the cathode zone and its coupling technology. The aim was to provide theoretical support for CSE in hydrogen production and low-carbon clean utilization of coal. In addition, this review also anticipated the future development direction of CSE and suggested that achieving a breakthrough in this technology relied on the development of high-performance electrode catalytic materials for CSE and the investigation of the regulation mechanism behind coal oxidation-reduction reactions.

High-value utilization of coal-based solid wastes is in urgent demands for the sustainable development of natural resources, and one promising strategy is to prepare zeolites by using coal-based solid wastes as raw materials. In this review, the formation mechanism and primary properties including chemical composition, mineral property, structural and morphological characteristics of four typical coal-based solid wastes (gangue, fly ash, gasification slag, and liquefaction slag) were introduced in detail. The main methods of activation pretreatments and zeolite crystallization were further summarized systematically. Moreover, the application advantages of zeolites prepared from coal-based solid wastes in gas/liquid adsorption and heterogeneous catalysis were discussed by specific cases. It is expected that more prospective studies on low-energy activation, diverse framework, and application exploration are highly desired for the synthesis and utilization of zeolites from coal-based solid wastes.

Treatment of the SO₂ and CO₂ in coal-fired flue gas is gradually developing to remove them simultaneously, and combined technologies based on the wet process of desulfurization and decarbonization have thus gained wide attention. Firstly, this paper systematically reviewed the main research directions of the stepwise (sequential) SO₂ and CO₂ removal technology. It was found that amine degradation caused by SO₂ is the core problem for this technology, but the mechanism was still in debate. The roles of desulfurization intensification and amine degradation inhibitors in alleviating the negative effects of SO₂ were analyzed from the perspectives of emission control and degradation prevention, respectively. Compared with stepwise treatment, the simultaneous SO₂ and CO₂ removal technology could achieve cyclic absorption and desorption based on a single solvent. Therefore, the latest progress of the simultaneous SO₂ and CO₂ removal technology was then summarized, including those using calcium-based, ammonia-based, and amine-based solvents. The principles and process design of each type of absorption system were sorted out and compared, and the most developed one was the ammonia-based combined processes. This paper also briefly described the advantages, disadvantages and development prospects of the two types of synergistic removal technologies. Finally, this paper suggested that future attention for the stepwise SO₂ and CO₂ removal technology should be focused on the mechanism of SO₂ caused_{amine degradation and its role in the development of degradation prevention measures, while for the combined removal technology, studies on reaction theory and integrated process modeling should be pursued.}

Our country has a large import volume of crude oil. At the same time, crude oil has gradually become heavier globally. The clean conversion of heavy oil in the refining industry is crucial, especially the efficient utilization of residue. Based on the difference kinds of residue, this paper analyzes the characteristics and catalysts R&D progress of different hydrotreating technologies, such as fixed bed, fluidized bed and slurry bed. This article also summarizes the conversion process of unconverted residue from hydrogenation to high value-added chemicals, and looks forward to several future development directions of refineries, including transitioning towards green, low-carbon, and integrated refining; utilizing the advantages of hydrogenation technology combination; developing high activity and low-cost catalysts, etc. Combination processing techniques can be reasonably chosen based on the properties of feedstock and product purpose. The hydrogenation technology of residue should better play its bridging role. Namely, using inferior feed oil to provide higher quality products for downstream processes, thereby achieving efficient utilization of residue.

The deployment of dry gas seal technology in supercritical carbon dioxide Brayton cycle turbine machinery, endowed with its exceptional sealing efficacy and stability, confers a safeguard for the secure operation of rotating machinery, while notably enhancing the shaft end sealing effect. In light of the distinctive physical properties of the sealing medium and the necessities of high-parameters operational milieu, intricate fluid lubrication theory is invoked in the investigation of thermodynamic performance of S-CO₂ dry gas seal. Owing to above discussion, this paper centered on the action mechanism and influence law of multifarious fluid effects and phase transition characteristics on the performance of S-CO₂ dry gas seal and flow heat transfer characteristics, elucidated in meticulous detail the analytical models and solution algorithms commonly employed in theoretical research, and thoroughly reviewed the theoretical and experimental investigations on the thermodynamic performance of S-CO₂ dry gas seal domestically and internationally. Subsequently, combining the demands of the field and existing advanced technologies, future developmental research trajectories were further proposed, with the aim of furnishing a theoretical reference for further inquiry into the correlative research and advancing the more application of dry gas seal technology in the future energy sector.

The Ordos lignite was separated into vitrinite-rich group (EL-V) and inertinite-rich group (EL-I) by floating-sinking separation method, and the structures and compositions of the raw coal and its maceral were analyzed by industrial analysis, elemental analysis, X-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FTIR) and solid state nuclear magnetic resonance (¹³C NMR). The pyrolysis characteristics and the escape pattern of gaseous volatiles of the raw coal and its maceral were investigated by powder-particle fluidized bed and TG-FTIR devices, respectively, to further construct the macromolecular structure models of the raw coal and its maceral and quantum chemical calculations were carried out to recognize the law of chemical bonds breaking. The results showed that the vitrinite-rich group had a higher content of volatiles, contained abundant alkyl side chains, and the largest heat weight loss rate, suggesting that the vitrinite-rich group was more reactive in pyrolysis. Compared with the raw coal and inertinite-rich group, the vitrinite-rich group had higher the pyrolysis gas content and tar contend, and its pyrolysis tar contained more aliphatic hydrocarbons and light aromatic hydrocarbons (TXE). The inertinite-rich group had lower H/C ratio, and higher oxygen content and aromatic ring condensation, and its pyrolysis tar contained higher PAHs and phenolics. In addition, the precipitation behaviors of CO₂, CO, CH₄, aliphatic hydrocarbons and aromatic hydrocarbons were analyzed by TG-FTIR. Based on the breaking of chemical bonds in the macromolecular structure of coal samples and the escape pattern of gaseous volatiles, the possible reaction routes carried out in the coal pyrolysis process were proposed.

Supported NiC/Al-MCM-41 and NiMoC/Al-MCM-41 catalysts were prepared by hydrothermal synthesis and utilized in pyrene hydrogenation. The catalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N₂ physical adsorption, NH₃ temperature-programmed desorption (NH₃-TPD), and thermogravimetric analysis (TG). The hydrogenation activity of the catalysts was evaluated in a batch high-pressure reactor. The effects of Mo doping on the physical-chemical structure and hydrogenation activity of NiC/Al-MCM-41 catalyst were investigated, and the structure-activity relationship between the physical and chemical properties of the catalyst and hydrogenation activity was explored. The results showed that the NiMoC/Al-MCM-41 catalyst exhibited the best hydrogenation activity and could be partially regenerated at a reaction temperature of 340℃, H₂ pressure of 6MPa, and continuous reaction for 2h. Compared with NiC/Al-MCM-41 catalyst, Mo doping increased the conversion of pyrene from 65.2% to 90.8% and deep hydrogenation selectivity from 58.9% to 76.2%, which effectively improved the hydrogenation performance of the catalyst. However, the stability of NiMoC/Al-MCM-41 catalyst was poor due to the carbon deposition caused by pore channel blocking of the catalyst, which hindered the diffusion and transfer of pyrene molecules in the pore channels. Therefore, the catalyst resistance to carbon deposition should be further improved in the future.

In this paper, a series of cordierite-loaded Fe/Ce composite oxygen carriers were prepared by ball milling method and the performance of the composite oxygen carriers for methane chemical looping reforming was evaluated on a fixed-bed reactor. The effects of cordierite mass fraction, Fe/Ce molar ratio, coconut shells addition and ball milling parameters on the redox properties of the composite oxygen carriers were systematically investigated and corresponding characterizations (XRD, H₂-TPR, BET, SEM, XPS) were performed. It was found that the composite oxygen carrier with 30% cordierite that loaded Fe/Ce at a molar ratio of 1∶9 and prepared under the ball milling parameters of ball material ratio of 10∶1, rotational speed of 500r/min, and time of 1h, had superior redox properties. The addition of 15% coconut shell carbon increased the actual oxygen output of the composite oxygen carrier by 38.7%, and also demonstrated a good reaction stability and oxygen release capability in the reduction-oxidation cycle reactions.

Pyrolysis is an important way to achieve the clean and efficient utilization of coal resources, and an in-depth understanding of the changes of volatile radicals during coal pyrolysis is crucial to the regulation of pyrolysis products, but it is difficult to capture the details of experimental methods. A classical lignite molecular model was used to investigate the evolution of volatile radicals and the reaction mechanism during the pyrolysis of low-rank coal in combination with reactive molecular dynamics (ReaxFF MD) simulations. The simulation results showed that the yield of volatile products increased with the increase of heating rate, and the faster heating rate inhibited the formation of gas products and increased the yield of tar products, but the degree of heavy tar was serious. The cracking of oxygen-containing functional groups was the triggering mechanism of coal pyrolysis, and the pyrolysis process was mainly divided into three stages: activation (800—1200K), pyrolysis (1200—2400K) and condensation (2400—2800K). In the high-temperature condensation stage, the tar fragments were more easily cross-linked with each other, and then the condensation reaction occured to form char, which was accompanied by gas generation, leading to a decrease in tar yield and an increase in gas and char production. Therefore, the key to improve tar yield and quality was to promote the cleavage of tar fragments and inhibit their polycondensation. The formation mechanism of gas-phase products was analyzed. CO₂ is mainly produced by the cleavage of carboxyl and ester groups; the cleavage of methoxy side chains and bridge bonds forms ·CH₃ and ·CH₂ radicals, which capture ·H and finally form the CH₄ molecule; the secondary pyrolysis and condensation of tar release a large amount of ·H and H₂, and the further reaction between ·H produces H₂; the thioether structure and nitrogen-containing branch chains in coal are decomposed, and then stabilized to H₂S and NH₃ by ·H free radicals. These mechanisms obtained from the molecular level can provide important references for experimental or industrial regulation of pyrolysis products.

At present, the use of binder additives for coal blending to reduce the proportion of coking/fat coal is an important way to decrease the cost and enhance the efficiency of the coking industry. Domestic and international studies have already demonstrated the feasibility of the substitution of coking/fat coal for coking by extracts from degradative solvent extraction of low-rank coals in the laboratory, but there has been no actual coking validation on a large scale. Accordingly, This paper built a low-rank coal degradative solvent extraction device and cooperated with several coking plants to complete the experimental validation of extracts replacing coking/fat coal in small coke ovens. The results showed that the extracts could significantly reduce the ash content of coke and maintain the coking performances of coke basically unchanged when replacing 20% of fat coal or 10% of coking coal. Moreover, the extract had a 72%—77% retention rate in the coke, which did not result in a significant reduction in coke yield. Therefore, this study clarified the feasibility of the extracts from degradative solvent extraction of low-rank coal to replace coking/fat coal, provided a new option for cost reduction and efficiency increase in the coking industry, and further promoted the progress of industrialization of the degradative solvent extraction of low-rank coal technology.

Electroflotation technology is an effective way to achieve efficient separation of coal macerals and it is also a hydrogen and oxygen production technology with significant advantages. Electrolytic bubbles in electroflotation are carriers for flotation separation and are also effective hydrogen/oxygen products. This study explored the impact mechanism of electrolytic bubbles on the separation efficiency of macerals in high-inertinite coal electroflotation. Induced timer, infrared spectroscopy, contact angle measurement, and gas chromatography were used to investigate the selectivity of hydrogen and oxygen bubbles for coal macerals, and the impact of electrochemical reaction on coal structure, flotability and gas product composition. The results showed that the yield and vitrinite content of the concentrates obtained by electrolytic hydrogen bubble flotation were higher than those with oxygen bubbles, and the corresponding vitrinite recovery rate was also higher than that with oxygen bubbles. The electrolytic action during the electroflotation process improved the surface structure of coal macerals, causing changes in wettability. The cathode region of electroflotation had an electrochemical reduction effect on coal, which could reduce the hydrophilic functional groups such as —OH, —COOH, and C\stackrel{}{̿}O in coal, thereby increasing the contact angle of coal samples and reducing the induction time of hydrogen bubbles on coal, thus increasing the floatability of coal. And the anode region had the opposite effect. In the electroflotation process of coal slurry, hydrogen gas with a purity of >94% and oxygen gas with a purity of >96% were obtained, and the purity of the gas products using vitrinite as electrolyte was higher than that with inertinite, but the inertinite could achieve a higher gas production rate. The two-stage series process was used for the electroflotation of coal macerals, and it had a maximum comprehensive efficiency of 83.7% for flotation separation. The recovery rate of vitrinite in the concentrates was 86.7%, and the recovery rates of the two sink products were 41.6% and 54.9%, respectively, while the hydrogen production rate reached 6.49mL/(min∙cm²).

The molecular structures of nitrogen compounds change regularly with the increase of oil distillation range. The relationship between the molecular structure of the nitrogen compounds and the hydrogenation behavior is an important guiding theory for the design of hydrodenitrogenation (HDN) catalysts. This study used theoretical calculation to investigate the variation in the properties and reaction behaviors of basic and non-basic nitrogen compounds with their structures. The results showed that the adsorption strength and charge transfer increased with the number of aromatic rings on the nitrogen compounds. In addition, the horizontal adsorption gradually became the dominated morphology instead of vertical adsorption. As the number of aromatic rings increased, it became more difficult to break C—N bonds through a low activation energy pathway. Instead, the bonds could only be broken through the substitution pathway with a high activation energy. Therefore, the break of the C—N bond required the saturation of the aromatic rings through full hydrogenation. The major nitrogen compounds in the products of the high hydrogenolysis capacity catalyst were polycyclic aromatics, whereas those of the catalyst with high hydrogenation saturation capacity contained more compounds with double aromatic rings. The results of hydrogenation experiments indicated that the catalyst with high hydrogenolysis ability offered higher HDN activities for the light distillate, whereas the catalyst with high hydrogenation ability performed better for the heavy distillate.

Wucaiwan sub-bituminous coal (WSBC) was subjected to alkanolysis using isopropanol as solvent at 300℃, and the soluble (SP) and insoluble (ISP) compounds were obtained. The GC/MS analysis showed that the aromatic content of SP accounted for the largest percentage of the total amount of SP, which was 27.9%, followed by phenolic compounds, which indicated that the compounds containing benzene rings were more easily extracted during the isopropanol alkanolysis. The infrared spectra showed that the intensity of the absorption peaks of ISP in both aliphatic and aromatic regions increased significantly relative to that of the original coal, suggesting that the alkanolysis process destroyed the macromolecular structure of the coal, and generated new functional groups through bond breaking and alkanolysis reactions. From the TG-DTG curves, it could be seen that the weight loss rate of the raw coal was larger than that of ISP, and the second weight loss rate peak appeared in the temperature range of 400—500℃ for both of them, in which the weight loss rate of WSBC reached the maximum at 450℃, and the temperature corresponding to the peak of the maximum weight loss rate of ISP was shifted to the right (480℃). The pyrolysis reaction of both samples was the most intense in the temperature interval of the second weight loss peak, which was attributed to the thermal cracking of the organic matter and a large amount of volatilization. The results of the Py-GC/MS showed that the detectable compounds in the pyrolysis products of WSBC and ISP at 450℃ were mainly aliphatic hydrocarbons and oxygenated compounds, and alkanolysis led to a significant decrease in oxygenated compounds, but did not obviously remove nitrogenous compounds from ISP.

Driven by the carbon neutrality goal, refining enterprises must find a new way to develop new low-carbon and zero-carbon refining technologies. The performance of bio-based fuels is similar to that of petroleum-based fuels, but its carbon emissions have been significantly reduced throughout its life cycle. Biomass fuels technology is becoming one of the important means for refineries to achieve low-carbon and zero-carbon development. Based on this, the research progress and development trend of the technologies related to the production of hydrocarbon fuels from biomass (b-Fuels) are reviewed, including the transesterification technology without glycerol generation and the transesterification technology controlling the selectivity of the products, the technologies of biomass pyrolysis, catalytic cracking and hydrocracking, and co-refining technologies of biomass and petroleum fractions. The technological development path of carbon neutrality for future refining and chemical enterprises is also discussed, with a view to the refinery transformation and development.

Biomass is a kind of renewable resource with great application potential, which has the characteristics of wide source, abundant reserves and low price. The preparation of biomass activated carbon is an important route to promote the resource utilization of biomass materials. In this paper, the preparation of activated carbon from biomass and the regulation of preparation conditions for its microstructural characteristics including specific surface area, pore structure and surface properties are reviewed. The effects of biomass composition, carbonization and activation conditions (such as carbonization method, activator type, activator dosage, and reaction residence time) on the microstructure characteristics of activated carbon are emphatically expounded. The regulation mechanism of pore structure and surface properties by common activators (such as water vapor, CO₂, ZnCl₂, H₃PO₄, KOH, etc.) is discussed in detail. Finally, this paper summarizes the applications of activated carbon with different microstructure characteristics.

Gas-pressurized (GP) torrefaction has the advantages of mild reaction conditions, low energy consumption, high deoxygenation efficiency, high energy recovery efficiency, and semi-coke fuel quality similar as subbitumiunous coal. It is one of the novel technologies promising to replace the traditional torrefaction. This review introduces the development of GP torrefaction, reviews the optimization of GP torrefaction conditions (including the raw biomass type, temperature, pressure and time) and product composition and physicochemical properties, explains the macroscopic reaction pathways and microscopic reaction mechanisms, focuses on the combustion, pyrolysis and gasification utilisation pathways of semi-coke, reviews the reactor design and expansion in solid waste treatment such as chlorinated solid waste, sludge, etc. Finally, the GP torrefaction technology converting biomass into high fuel quality solid fuel which can directly replace coal is summarised and prospected.

Lignin can be used to obtain many kinds of fuels, chemicals and materials through rational processing and conversion. Extracting lignin by gentle method is the premise of realizing the high value utilization of lignin. In this paper, the separation methods and research progress of lignin in recent years are reviewed, with emphasis on the separation mechanism of various separation methods and the composition and structure characteristics of lignin. The advantages and disadvantages, applicability and industrial application of different separation methods are summarized. Acid method promotes the hydrolysis of ether bond in polysaccharide polymer to depolymerize hemicellulose and cellulose. Alkali method mainly cracks the ether and ester bond between lignin and carbohydrate. Acid method and alkali method are mature as traditional lignin separation methods, but they are easy to cause the self-polymerization of lignin. Organic solvent method mainly destroys the β-aryl ether bond, and its separation condition is mild, which can better retain the original structure and reactivity of lignin. New green solvent systems such as ionic liquid and deep eutectic solvent have dual functions of solvent and reaction medium, and have received extensive attention. The coupling of separation methods and the assistance of physical, chemical or biological technology will play an important role in optimizing the separation process of lignin and exploring the high-value utilization of lignin.

5-hydroxymethylfurfural (HMF) is one of paramount platform chemicals for converting biomass into chemicals, fuels and polyester materials. The rational design of efficient catalysts, optimization of catalytic reaction processes, and development of the novel separation and reaction-separation coupling technologies can enhance the comprehensive efficiency in production of HMF, simplify the unit processes, and reduce carbon emissions and energy consumption. In this paper, the state-of-the-art towards catalytic reactions, separation technology and process coupling related during acid-catalyzed dehydration of hexoses to HMF were reviewed from the fundamentals in designing the bifunctional active sites for relay catalysis, integration of tandem reactions, regulation of surface hydrophilicity and hydrophobicity, selection of reaction medium, adsorbent materials, adsorption mechanism and structure-performance relationship, as well as process intensification. The knowledge and learning points gained from this review would be instructive for research communities working on catalysis and separation in biomass utilization.

The ammonia industry has made outstanding contributions to human food security and economic and social development, while also causing a large amount of carbon dioxide emissions in the production process. Green ammonia produced using renewable energy has the characteristic of “zero carbon” and significant carbon reduction effects throughout its lifecycle. It has become one of the hotspots for low-carbon industry development worldwide. this paper introduces the policies of the green ammonia industry, the current development status and progress of the green ammonia industry, and analyzes the market competitiveness of green ammonia in four downstream applications such as vehicle and ship fuel, hydrogen storage carriers, fuel power generation, and chemical raw materials. It is considered that the major global ship engine technology companies and ship manufacturers are developing ammonia fuel engines and ammonia powered ships which are gradually conducting operational tests. And the ammonia fuel engines for vehicles have achieved breakthroughs in related technologies in China. It is believed that ocean shipping is the first breakthrough area for green ammonia, and when the price of green electricity drops to around 0.20CNY/kWh with the advancement of new energy technology, global green ammonia vehicle and ship fuel will usher in significant development. Green ammonia will become increasingly cost competitive in the heavy-duty truck and ocean shipping industries. At the same time, ammonia has great potential for development as a hydrogen storage carrier. The cost of liquid ammonia synthesis and dehydrogenation accounts for over 85% of the total cost, and it is not sensitive to transportation distance. In the future, it will become one of the main forms of global long-distance transportation of bulk hydrogen. The sustainable development of the green ammonia industry requires support from technological innovation, industrial policies, and standard formulation.

Due to the new policies in the sector of marine transportation and strict emission regulations, fuel cells for marine application have received more and more attention, especially the proton exchange membrane fuel cell (PEMFC) system with high efficiency, low noise and modularity. This paper introduces the marine PEMFC system developed by Sunrise Power Co., Ltd., which is equipped with multiple safety parameter detection devices, adopts a targeted scheme for the selection of BOP components, and achieves the rated efficiency and peak efficiency of 45% and 62% respectively through water and heat management optimization and calibration. In order to prove the PEMFC system meeting the requirements of perfect function, safety and reliability, the performance evaluation test is studied and formulated by the methods of design tests, which are reliability test, cold start test and dual-machine parallel test. The test results show that after 200h dynamic working condition test, the performance of the system does not change at intermediate power, and the performance degradation rate of the stack is 1.2% at the rated power. Based on good water and heat management and multi-mode control methods, the purge time and cell voltage deviation are greatly reduced, and the cold start is successfully achieved when the ambient temperature is -30℃, which exceeds the most demanding requirements in the marine specification. Under the high-power demand and redundancy design goals, the double-PEMFCs makes the power output of the system assembly more stable and reliable. The system durability is improved through the alternate start strategy, and different working modes provide the basic conditions for system maintenance and trouble shooting. The PEMFC system has the ability to carry real ship applications. This paper provides a reference for the design and development of marine PEMFC systems.

To effectively address the low-temperature heat and CO₂ in industrial flue gas, a thermal regenerative battery stack coupled with an electrochemical reduction reaction of carbon dioxide system (TRB-CO₂RR) was developed. A stack was constructed by connecting several non-aqueous thermally regenerative batteries in series, serving to drive an electrochemical reduction of CO₂. The characteristics of CO₂RR, the performance of the non-aqueous TRB stack, and the coupling characteristics of the non-aqueous TRB-CO₂RR system were studied. The results demonstrated a relatively uniform distribution of catalyst on a carbon paper-supported silver nanoparticle porous electrode. The optimal CO₂RR_{performance was observed at a potential of -1.8V (corresponding to a slot voltage of 5.1V), with a CO Faraday efficiency reaching a peak of 78.7%. Therefore, a series stack of six batteries was constructed. The open circuit voltage reached approximately 7.2V, with a maximum power of 235mW and a relatively stable discharge lasting for 34min. In the non-aqueous TRB-CO2RR coupled system, no reverse pole phenomenon was observed in the stack, and the CO Faraday efficiency (73.1%) closely approached the optimum value achieved by a stable power supply. Further research could be focused on optimizing catalysts and stack design, aiming to improve the efficiency of CO2RR in this coupled system.}

In order to verify the long-term operation stability of the two-stage fluidized bed gasification process, commercial fruit charcoal semi-coke is used as the catalytic bed material for the preparation of clean gas by pine fluidized two-stage gasification in this experiment. In the early stage of the experiment, a stable and effective catalytic semi-coke bed layer is formed to reduce the accumulation period of semi-coke, so as to quickly reach high-efficiency tar removal in the system. The excess air coefficient (ER) is maintained at 0.35, the gas velocity in the riser is 3m/s, and the oxygen concentration in the fluidization medium is gradually adjusted to gradually increase the biomass processing capacity. The results show that as the feed rate of pine particles increases from 1kg/h to 3kg/h, the volume percentages of CO and H₂ in the product gas increase from 7.71% and 3.13% to 16.15% and 12.60%, respectively, while the volume percentage of CH₄ slightly decreases. The gas yield also increases from 0.90m³/kg to 1.36m³/kg, and the corresponding calorific value of the product gas increases from 3.26MJ/m³ to 4.80MJ/m³. Through multiple manual start-stop and change of operating parameters, during the entire 12h operating cycle, the semi-coke produced by the fluidized two-stage gasification matches the speed of semi-coke consumption, and the temperature and pressure show good operating stability. This result proves that the two-stage fluidized bed gasification process has technological advancement and long-term operation stability in the production of gas from biomass.

Phthalic anhydride is an important raw material for synthesizing high-value fine chemicals, such as plasticizers and coatings. In the recent decades, the production of phthalic anhydride from o-xylene is the main industrial process with minor from naphthalene. Vanadium-based catalysts are primarily employed in industry and have been widely studied due to their high selectivity for phthalic anhydride. In order to increase the yield of phthalic anhydride and reduce the bed temperature, strategies of multi-stage catalyst beds and high load have been gradually developed. This article focuses on the o-xylene synthesis process with a brief introduction of the development history of catalysts. Especially, the synthetic routes and catalytic mechanisms are discussed in detail. The application of industrial catalysts often faces deactivation problems, such as carbon compound deposition, loss of active components and TiO₂ anatase-rutile transformation. Thus, the deactivation mechanism of catalysts is also discussed in detail. Finally, prospects for the development of synthetic technologies of phthalic anhydride are proposed. Towards the industrial problems of high energy consumption, CO _x generation, and short catalyst life, efforts should be made to develop new efficient catalysts and green reaction processes for the phthalic anhydride synthesis, so as to promote the sustainable development of this technology in the future.

As an important carrier of acid-catalyzed thermal reaction, zeolite has the advantages of controllable acidity, strong thermal stability and shape selectivity, but its special rigid pore structure and internal charge distribution make it have a limiting effect, which will affect the zeolite’s acidic characterization and catalytic reaction performance. Since the catalytic role of zeolite is mainly the Brønsted acid site, the formation mechanism of the Brønsted acid site and the confinement effect is introduced, the influence of the restriction effect on the acid strength and acid density characterization of the Brønsted acid site is briefly described, and the influence of spatial constraint and local electric field on the catalytic reaction performance in the restriction effect is reviewed. It is pointed out that in the acidic characterization, spatial constraints limit the accessibility of probe molecules to acid sites, which further affects the measurement of acid density. The local electric field affects the adsorption and desorption of probe molecules, which in turn directly affects the acid intensity. Therefore, in the acidic characterization of zeolites, probe molecules with similar size and structure to reactants should be selected to measure the acid density and acid strength that can be acquired as the actual results close to the Brønsted acid site. In catalytically dominated thermochemical reactions, spatial constraints make zeolites shape-selective, and the reaction process, intermediate-transition-state product and final product distribution of thermochemical reactions can be selected by controlling the pore size of zeolite. At the same time, since the local electric field affects the apparent acid intensity, the catalytic performance of zeolite is related to the apparent acid intensity. The smaller the pore size of the zeolite, the greater the van der Waals interaction of the reaction molecules, which affects the formation of the transition state of the reaction and then changes the activation energy of the reaction, thereby affecting the catalytic thermochemical reaction efficacy. Comprehensive analysis shows that only a zeolite with appropriate acid strength and an accessible pore size similar to that of the reactant molecule is an ideal acid carrier for catalyzing the thermal reaction.

Direct methanol fuel cells (DMFCs) have gained attention because of their potential to provide clean, sustainable energy at lower temperatures. However, the slow methanol oxidation reaction (MOR) at anode has limited their commercial use. In contrast, photo-assisted direct methanol fuel cells (PMFCs) can accelerate the MOR process by a photoelectric coupling mechanism, which efficiently converts methanol’s chemical energy into electricity, and thus show great promise for developing efficient and sustainable energy conversion systems. This paper begins with a brief review of the background, significance, and value of PMFCs in energy research. It then summarizes the research progress of anode photocatalysts for PMFCs, starting from the basic structure and pathway of methanol photo electrocatalytic oxidation under an acid-base medium. According to different types of anodic photocatalysts for PMFCs, we discuss the mechanisms that may intensify the photo-assisted MOR, such as the catalyst size effect, crystal surface effect, light absorption property, electrical conductivity, and surface plasmon resonance (SPR). The future research direction for PMFCs should focus on understanding the mechanism of photoelectric coupling and the constitutive relationship of anodic catalysts in-depth. Additionally, it is crucial to address the design problems of the PMFCs photo-anode under the actual two-electrode system.

Sorption enhanced water gas shift reaction (SEWGS) is one of the critical reactions for high-purity hydrogen preparation and carbon dioxide emission reduction. The composite catalyst is utilized to couple catalytic water gas shift (hydrogen production) with in-situ CO₂ removal (decarbonization) during SEWGS, which could break the thermodynamic limitations by moving the chemical equilibrium towards the hydrogen production to achieve enhanced hydrogen production. SEWGS has the characteristic of one-step production of high-purity hydrogen. However, problems with the composite catalyst, such as sintering and hindered CO₂ diffusion during continuous SEWGS hydrogen production, lead to a decrease in cycle stability, thereby affecting the hydrogen production efficiency. This work elaborates on the current research status of high-temperature Ni/CaO-based composite catalysts for sorption enhanced hydrogen production. The existing problems of Fe/CaO-based composite catalysts in SEWGS for hydrogen production are briefly described. The current status and core problems of medium temperature Cu/MgO-based and Cu/layer double hydroxides are discussed. From the perspectives of the catalytic components and the sorbent components of composite catalysts, the reasons for the reduced stability are analyzed, and the most effective modification methods currently available are briefly described. Furthermore, modification strategies are proposed from the design of the composite catalyst, operational conditions, and bed loading methods of reactor, to improve the cycle stability of composite catalyst, focusing on enhancing CO₂ diffusion and lowering sintering resistance. It highlights that the design and development of composite catalysts that are simple in composition, easy to prepare, as well as high activity and stability, for the coupled production of hydrogen and decarbonization, are the future research direction in SEWGS for hydrogen production.

Leather collagen is a kind of natural biomass material derived from animal skin. The advantages of good biocompatibility, degradability, low antigenicity and easy functionalization make the leather collagen showing great application potential in flexible intelligent wearable fields such as flexible sensing, electromagnetic shielding, human thermal management and energy storage. However, some inherent shortcomings, such as poor thermal stability, low mechanical strength and easy to mildew and insufficient functionality, limite the application of leather collagen in the field of flexible intelligent wearable. In this review, the multilevel structure and performance advantages of leather collagen were briefly introduced. Different modification methods of collagen were discussed, including physical crosslinking, chemical crosslinking and blending modification. In addition, this review paid more attention to the research progress of leather collagen as flexible wearable materials in flexible sensing, electromagnetic shielding, human thermal management and supercapacitors. Finally, the development trend of leather collagen in the field of flexible wearable electronics was forecasted, and it was pointed out that the development of multi-functional integrated leather collagen flexible wearable electronic materials with extreme environmental stability and the realization of on-demand customization of flexible intelligent wearable materials based on leather collagen would be the focus of further research.

Single-crystalline hierarchical ZSM-5 zeolite with intracrystalline mesopore was successfully synthesized by using L-lysine as a mesoporous template, and the Si/Al ratio was changed by adjusting the adding amount of aluminum source (sodium metaaluminate). Then the effect of acidic properties on zeolite’s activity and mass transfer in n-heptane catalytic cracking was investigated in detail. The physical structure, acidic properties and micromorphology of single-crystalline hierarchical ZSM-5 zeolite were characterized by using X-ray diffraction (XRD), nitrogen physical adsorption, ammonia temperature-programmed desorption (NH₃-TPD), pyridine infrared (Py-IR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In addition, the zero-length column (ZLC) device was employed to test the apparent diffusivity of n-heptane in single-crystalline hierarchical ZSM-5 zeolite,which was used to characterize its mass transfer performance. The results showed that the physical structure of single-crystalline hierarchical ZSM-5 zeolite kept almost the same with the increase of Si/Al ratio, while the zeolite’s mass transfer performance was improved with the decrease of acid amount, but the catalytic cracking performance was enhanced with the increase of acid amount. When the Si/Al ratio of the single-crystalline hierarchical ZSM-5 zeolite increased from 80 to 140, the apparent diffusivity of n-heptane could be improved by more than 87%. When the Si/Al ratio was 80, the conversion rate of n-heptane could reach up to 97.5%, and the selectivity of ethylene and propylene were 24.3% and 35.1%, respectively.

Aqueous zinc ion capacitors (ZICs) composed of porous carbon cathode and Zn metal anode have attracted great research interest in recent years due to their advantages of low cost, environmental friendliness, high safety, and long-term durability. This work first synthesized a N-containing polymer as the precursor by condensation of melamine chloride and p-phenylenediamine, and then fabricated N-enriched porous carbon nanosheets (NPCN-x) with a high N content (>10%) by a carbonization and self-activation strategy. The influence of carbonization temperature on the morphology, microstructure, surface chemical properties, and electrochemical performance of NPCN-x was investigated in detail. The results showed that carbonization temperature had a significant regulation effect on the N-doped configurations. It was revealed that the pyrrolic N configuration within NPCN-x materials played a crucial role in improving their electrochemical performance. As a consequence, the optimized NPCN-800 sample with the highest pyrrolic N content of 2.15% delivered a high specific capacity up to 158mAh/g at 0.5A/g and excellent cycling performance as the cathode for ZICs. To further explore the storage mechanism of Zn ions on the N-doped carbon surface during the electrochemical process, density functional theory (DFT) calculations were performed, which showed that the pyrrolic N configuration possessed the strongest adsorption capability for Zn ions, suggesting superior electrochemical activity in comparison to other N-doped configurations. This work provided a new insight from both theoretical and experimental perspectives for constructing porous carbon materials for high-performance ZICs.

The selectivity of syngas-to-C₂ oxygenates still faces a big challenge. Using density functional theory calculation methods, this study explores the influence of the confined environment of Rh active sites on the reaction performance of syngas conversion to CH _x over four types of RhCu confined catalysts, which further reveals the essential reasons of the confinement effect to regulate the catalytic performance. The results showed that the confined environment of Rh active sites in the RhCu confined catalysts can regulate the activity and selectivity of syngas conversion to generate CH _x . The screened catalyst could perform the highest catalytic activity toward syngas conversion to generate CH _x (x=1—3) monomer. The moderate confinement effect of catalyst made the d-band center of surface atoms far away from the Fermi level, leading to an appropriate electron gain and loss between the transition state of CH₂OH dissociation and RhCu surface, which was conducive to the dissociation of CH₂OH into CH₂ and thus exhibited excellent CH _x formation activity. This study provides theoretical basis for improving the catalytic performance of syngas conversion to C₂ oxygenates by adjusting the confined environment of active site and provides the structural clues for the design of the confined metal single-atom catalysts.

The external surface of 2D (two-dimensional) ZSM-5 zeolite was passivated by fabricating full silica Silicalite-1 through secondary crystallization technique. The obtained catalysts were characterized by XRD, SEM, TEM, N₂ adsorption-desorption isotherms, and Py-IR, etc. The catalytic performances of the surface passivated two-dimensional ZSM-5 zeolite in the alkylation between toluene and methanol were evaluated in a fixed-bed reactor. The characterization results showed that the full silica Silicalite-1 passivated 2D ZSM-5 zeolites with internal 2D lamellar structure were successfully constructed, and the Silicalite-1 not only effectively shielded the Brønsted acid sites on the external surface of 2D ZSM-5 zeolite and inhibited the occurrence of xylene isomerization, but also possessed the ability of shape-selectivity towards PX (p-xylene), which greatly improved the selectivity of p-xylene. The surface passivated 2D ZSM-5 zeolite also showed a long lifetime at 673K, and WHSV=10h^-1, and maintained high activity after 40h, with the selectivity of p-xylene about 35%, indicating an excellent catalytic performance in the alkylation of toluene with methanol. The present research could accelerate the industrialization procedure of alkylation between toluene and methanol.

Carbon dioxide and methane are the main greenhouse gases, and their conversion and utilization could contribute to the realization of “dual carbon” target. CH₄/CO₂ conversion via plasma method gets both gas and liquid products, giving the target product low selectivity. Plasma combined with catalysts can effectively improve the selectivity of target product. In this work, active metals of Ni, Fe, and Cu are loaded on γ-Al₂O₃ by micro-combustion method, and their reaction performance for CH₄/CO₂ conversion is significantly improved in combination with plasma. Metal loading changes the oxygen vacancy ratio of the catalyst and strengths the intensity of basic sites, which boosts CO₂ conversion. The weak acid of the metal catalyst enhances the liquid product selectivity, such as Lewis acid benefits the conversion to alcohol products, while Brønsted acid promotes the generation of acetic acid. Metal catalysts enhance the dielectric barrier discharge power, transfer more charge and increase the reaction energy efficiency. This study reveals the influence of catalyst structure on product selectivity and is conducive to the rational design of catalysts for plasma catalysis.

Photosynthesis of high-value multi-carbon chemicals from carbon dioxide (CO₂) represents an exceptionally promising avenue for green technology development, offering a dual solution to the challenges of greenhouse gas accumulation and the looming energy crisis. Designing photocatalysts with charge-polarized active sites can effectively lower the energy barriers for C-C coupling reaction, which significantly boosts the selectivity and efficiency of multi-carbon chemical synthesis. This paper provides a comprehensive review of the latest advances in the photocatalytic reduction of CO₂ to C₂ chemicals, exploring the pivotal strategies for engineering charge asymmetry at active sites. It also elucidates the activity and selectivity of C₂ products regulatory mechanisms at the microscopic level influenced by charge polarization effects. This paper summarizes the most promising approach for the design and development of efficient photocatalysts, providing theoretical and practical guidance for the actual application of photocatalytic technology. Moving forward, it is imperative to concentrate on the precise control at the atomic level of catalysts, and to develop more efficient and specific multi-carbon product preparation systems, thereby supporting the low-carbon transformation of the energy industry structure.

The urgency of addressing the greenhouse effect produced by CO₂ emissions is growing due to the economy’s rapid development. Reducing CO₂ emissions and slowing down global warming can be accomplished by reacting CO₂ with green hydrogen to produce value-added chemical compounds like methanol. Recently, CeO₂-supported metal catalysts for CO₂ hydrogenation to methanol have received extensive attentions. In this review, the importance of CeO₂ surface oxygen vacancy, basic sites, Ce³⁺/Ce⁴⁺ reversible redox ability, and unique geometric morphology were highlighted in the processes of CO₂/H₂ adsorption and activation and methanol formation. Moreover, the catalytic activities between CeO₂ and ZrO₂, ZnO and composite metal oxides supports were compared. Finally, the shortcomings and challenges in identifying active key intermediates, compromising between CO₂ conversion and methanol selectivity, and improving the catalytic activity and stability of CeO₂-based catalysts were highlighted. This work could provide useful advises for further design of CO₂ hydrogenation to methanol catalysts.

Supported amine adsorbents are a prominent subject of research within the realm of solid adsorption techniques for CO₂ capture, representing an area of considerable interest and applicability in the field of flue gas carbon capture and direct air capture technologies, and have received extensive attention. Nevertheless, there exists substantial room for improvement regarding the adsorption-desorption performance and thermochemical stability of supported amine adsorbents. This review focused on the study of the performance improvement of supported amine adsorbents through introducing additives. It provided a review of recent research on enhancing the adsorption performance of supported amine adsorbents through the utilization of additives, encompassing surfactants, amine-based additives and inorganic additives. Additionally, it delved into the achievements of research efforts aimed at enhancing the thermochemical stability of supported amine adsorbents through the application of epoxides, chelators and sulfur-containing additives. Furthermore, this review elucidated the underlying mechanisms governing the performance improvement of supported amine adsorbents via various categories of additives and summarized the performance improvement characteristics of distinct types of additives for supported amine adsorbents under different carbon capture conditions. Despite some progress in research, the performance improvement of supported amine adsorbents through additives still faced challenges. Presently, research had not fully achieved the dual objectives of enhancing the adsorption performance and thermochemical stability of supported amine adsorbents. Moreover, given the significant variation in gas composition under different carbon capture conditions, future research needed to clarify the impact of additives on the thermodynamics, kinetics and thermochemical stability of supported amine adsorbents under different carbon capture scenarios, and design additive modification strategies accordingly.

The conversion of carbon dioxide (CO₂) to valuable syngas (CO/H₂) by electrocatalytic carbon dioxide reduction reaction (CRR) has attracted widespread attention. The development of electrocatalysts for CRR is crucial for efficient and accurate synthesis of syngas. This article reviews the research progress on the reaction process, reaction mechanism, and the electrocatalysts of CRR to syngas. The types, advantages, existing problems, and development directions of existing CRR catalysts were introduced. The influence of the types and proportions of doping elements in catalysts on the reaction intermediates were analyzed in detail. The effects of the edge and active site of the metal atom doped with non-metallic elements on CRR were pointed out. The precise regulation CO and H₂ by catalyst design and reaction condition adjustment were discussed. The article also discusses the ways to promote CRR and regulate the hydrocarbon ratio of syngas such as increasing reaction active sites and reducing the reaction energy barrier of intermediates. Furthermore, it was concluded that the efficiency of CRR to syngas could be improved through multi-stage regulation of catalyst morphology, multi-active site design, and the coupling of CO₂ reduction and anodic reaction. Finally, the challenges and issues in future industrial production of syngas through CRR were discussed.

The synthesis of high value-added methanol by hydrogenation of excess CO₂ is limited by thermodynamics equilibrium, resulting in lower conversion and utilization efficiency of raw materials. Product transformation and separation can promote the forward progress of CO₂ hydrogenation reaction. This article centers around two most typical methods, namely using methanol as an intermediate to further produce low-carbon olefins and aromatics, and utilizing membrane reactors to remove by-product water in situ. The research progress in promoting CO₂ hydrogenation process through the above two means is specifically discussed from the aspects of condition optimization of coupled reaction, catalysts preparation, and membrane reactors design and modification. The influence of acidity and pore structure of molecular sieve supports on coupled reaction performance is also analyzed. Moreover, the key and challenge for further research of membrane reactors is to improve the preparation repeatability.

To overcome the problems of uncontrollable active sites and microstructures of catalysts, the utilization of solid precursor as a controlled-release source of metal ions has emerged as a promising approach for fabricating metal-based integrated catalysts with precise microstructures and well-defined spatial configuration of active sites, therefore realizing the rational design of catalysts. This review highlights four types of solid precursor materials, namely transition metal phyllosilicates, layered double hydroxides, metal-organic frameworks, and bismuth vanadate materials, for the preparation of catalysts for thermal catalytic hydrogenation of CO₂. The review provides an overview of preparation mechanisms and application examples of these four integrated catalyst materials, along with an outlook on the research direction of developing multi-component integrated catalysts based on solid precursors.

The cycloaddition of CO₂ with epoxide is an effective and sustainable strategy for the chemical conversion of CO₂, and its product, cyclic carbonate, is applied widely in the fields of lithium-ion batteries and polymer materials. For the cycloaddition of CO₂ with epoxide, it is crucial to construct catalysts with efficient epoxide adsorption activation sites since the ring-opening of the epoxide is deemed to be the key step. In this paper, TA-Zr-2, a non-homogeneous tannic acid-zirconium mesoporous material containing both Lewis acid site of zirconium metal center and hydrogen-bonding site of phenolic hydroxyl, was prepared via the coordination of tannic acid and zirconium ions. XPS and epichlorohydrin TPD-MS results showed that the zirconium metal center of TA-Zr-2 had stronger Lewis acidity and adsorption activation to epoxypropane compared to UiO-66 which was also a zirconium-based porous material. The TA-Zr-2-FD catalyst was obtained by freeze-drying treatment on basis of TA-Zr-2, and the catalytic performance was improved 1 times to TA-Zr-2 with 97.6% yield of butylene carbonate due to the larger specific surface area and suitable pore volume. In summary, a tannic acid-zirconium mesoporous material with large specific surface area was constructed by using a simple and green preparation method. The synergy of zirconium Lewis acid site and phenol hydroxyl hydrogen-bonding was beneficial to the adsorption and activation of epoxide, thus facilitating the epoxide ring-opening and enabling the catalyst to exhibit good catalytic performance for cycloaddition of CO₂ with epoxide at 25℃.

The rectisol process for capturing CO₂ requires low-temperature environment, a significant amount of freezing energy, and considerable energy consumption. Introducing nanoparticles into absorbents can effectively enhance the gas-liquid mass transfer rate and reduce energy consumption. This study aimed to develop methanol-based nanofluids with reduced cooling demand and improved absorption and desorption performance. The effects of factors such as the type of nanoparticles, solid loading, particle size, surfactant content, temperature, and initial CO₂ concentration on CO₂ capture performance were investigated, and the impact mechanisms were studied. The results indicated that the CO₂ absorption and desorption enhancement effect of TiO₂-methanol nanofluid with a concentration of 0.4g/L was the best among TiO₂, Al₂O₃ and SiO₂ nanofluids with concentrations ranging from 0.2—1.0g/L. After adding 0.10% polyethylene glycol octylphenyl ether (Triton X-100), the absorption and desorption enhancement effect of the nanofluid were the highest, and it still showed a noteworthy enhancement effect after 5 cycles. Furthermore, this article provided an in-depth analysis of the mechanism of enhanced absorption of nanofluids and proposed an empirical formula to predict the enhancement factor E and optimal solid loading of TiO₂-methanol nanofluids.

In order to obtain the safe shutdown time of supercritical CO₂ pipeline, the commercial software OLGA was used to establish a calculation model of pipeline safety shutdown time under multi-factor synergy. Based on the parameter range of supercritical CO₂ pipeline engineering planned by PetroChina Xinjiang Oilfield Company, the influencing factors of pipeline safety shutdown time, such as pipeline capacity, pipe diameter, pipe length, initial station outlet temperature, soil environment temperature, total heat transfer coefficient, and terminal station inlet pressure, were studied, and sensitive factors such as soil environmental temperature and pipe length were obtained based on the gray correlation analysis method. In order to predict safe shutdown time of pipelines, based on above parametric analysis of 1728 sets of safe shutdown time results, a database of pipeline safety shutdown time was established. Combined with the methods of dimensional analysis, Python fitting was used to obtain a high nonlinear regression calculation formula for mapping seven variable parameters (independent variables) and supercritical CO₂ pipeline safety shutdown time (dependent variable). The results showed that the maximum relative error of prediction results of fitting formula was less than 10%, showing good prediction accuracy, and the method has high computational efficiency.

In recent years, the production of methanol by CO₂ hydrogenation with green hydrogen produced from renewable energy sources has received a lot of attention. However, the CO₂ conversion and methanol selectivity of the reaction are limited by the thermodynamic equilibrium of CO₂ catalytic hydrogenation reaction. Moreover, the presence of water as a byproduct usually leads to catalyst deactivation. In this study, a mother liquid seeding method was used to prepare defect-free single-channel NaA zeolite membrane. Then Cu-based catalysts were filled on the membrane to create a zeolite membrane-catalyst bifunctional reaction system that allowed for the simultaneous hydrogenation of CO₂ to produce methanol and the on-line selective removal of water. XRD, SEM, N₂ isothermal adsorption-desorption, and H₂-TPR were used to characterize the physical and chemical properties of the NaA zeolite membranes and the catalysts. The catalysts performance for CO₂ hydrogenation were evaluated by the membrane reactor. The results showed that the reaction system can significantly increase the CO₂ conversion and effectively drive the reaction equilibrium forward compared with the conventional fixed-bed reactor. The CO₂ conversion was increased from 3.34% to 28.78% and the methanol yield was promoted from 3.28% to 27.62% at 250℃ and 3MPa.

The utilization rate of CO₂ and H₂ raw materials is an important factor affecting the process economy of CO₂ hydrogenation to methanol. The influences of catalyst type, temperature, pressure, space velocity and H₂/CO₂ feed ratio on CO₂ conversion and methanol selectivity, and the influences of process conditions on the loss of carbon and hydrogen in gas and liquid phase were discussed, respectively. A cycle process for CO₂ hydrogenation to methanol was proposed by introducing the stripping unit to recover the dissolved CO₂ from liquid phase. The effects of purge gas on carbon and hydrogen utilization and process economy were studied to determine the optimal rate of purge gas. The results showed that the loss of dissolved CO₂ was negligible after stripping separation and the loss of carbon and hydrogen mainly depended on the purge gas. The equipment investment cost decreased gradually with the increase of the purge gas flowrate while the unit production cost firstly decreased and then increased. The utilization rate of CO₂ and H₂ were respectively 98.9% and 65.9% when the flow rate ratio of purge to feed was set as 1%. Compared with the traditional process, the proposed process had an effective utilization of raw materials. This study provides a feasible path for efficient conversion of CO₂ hydrogenation to methanol.

The life cycle assessment (LCA) method is widely used for the systematic identification and assessment of environmental issues among different products and processes, especially for identifying pollutant emissions and minimizing the environmental impacts of products and processes. Pharmaceutical chemicals and intermediates are usually more complex, which result in greater environmental impacts than basic bulk chemicals. Therefore, LCA can systematically quantify and analyze the potential environmental impacts of the entire life cycle of products in the pharmaceutical field to support the “dual-carbon” goal of China. This paper briefly describes the four steps of the LCA method, including goal and scope definition, life cycle inventory, life cycle impact assessment, and life cycle interpretation. On this basis, the current status and research progress of the application of LCA in the pharmaceutical field are specified from the aspects of drug production, medical devices, and medical services. Additionally, the crucial existing problems in the pharmaceutical LCA studies are identified, such as relatively rare studies, difficult in the data collection, especially for drug intermediates which usually have complex structures, lack of the life cycle upstream data, the low accuracy of the data, and inconsistency in the LCA method. Finally, relevant suggestions are proposed to support the sustainable development of the pharmaceutical field from the life cycle perspective.

China’s coke production amounts to 4.73×10⁸t million tons, and the by-production of coke oven gas is about 2×10¹¹m³. Coke oven gas is rich in hydrocarbon resources such as H₂, CH₄, and CO. Its effective utilization and integration with the hydrogen energy demand of upstream and downstream industries are expected to generate significant carbon reduction benefits in the industry chain. This study constructs a spatial geographic coordinate and production capacity database of coke enterprises nationwide and conducts material flow and carbon flow analysis for typical coke enterprises. It systematically compares the environmental impacts, carbon emission reduction benefits, and hydrocarbon resource utilization efficiency of different utilization paths of coke oven gas, and proposes optimized strategies for the utilization of coke oven gas. The results show that the concentration of coking enterprises in China is relatively low. Shanxi is the province having the largest number of independent coking enterprises, with an a scale of less than 2×10⁶t. Hebei, Liaoning, Jilin and Jiangsu have steel and coke joint ventures, which are mainly large-scale coking enterprises. The coke industry produces a large amount of by-product coke oven gas, which can generate hydrogen gas up to 1×10¹¹m³ of hydrogen gas. The results of the life cycle assessment show that coke oven gas used for chemical conversion and reductant blast furnace blowing can effectively reduce carbon emissions compared with direct power generation as a fuel. Especially the hydrogen production pathway and blast furnace blowing pathway have 5 times and 67 times higher GWP reductions than the methanol production pathway, respectively. In addition, for the various coke oven gas utilization pathways, the total environmental impacts are ranked in descending order as methanol production, power generation, LNG production, ammonia production, hydrogen production, and blast furnace blowing. Based on with the analysis of various coke oven gas utilization paths and the spatial distribution of steel and coke enterprises, Shanxi and other places with more independent coking enterprises can give priority to the transition to the direction of coke oven gas hydrogen production. And in regions with conditions for the development of steel and coke joint, such as Hebei, Liaoning, Jilin, Jiangsu and other places, the transformation to the blast furnace blowing coke oven gas process is more conducive to produce inter-industry synergistic benefits, and effectively promote the development of pollution reduction and carbon reduction.

As a by-product in coking production, coke oven gas (COG) has been widely utilized for liquefied natural gas (LNG) production due to rich in H₂ and CH₄. To systematically evaluate the energy depletion and environmental impacts, as well as the carbon emission, life cycle assessment (LCA) method was applied to compare two COG-based LNG processes (decarbonization process and methanation process). The results show that LNG production is the crucial phase in the overall environmental impacts for both COG-based LNG processes. In decarbonization process, medium-pressure steam is the main contributing substance of life cycle environmental impacts. Recovering the waste heat of red coke by coke dry quenching system and supplementing LNG production consumption with by-product steam can largely reduce environmental loading. In methanation process, electricity is the key substance, accounting for 41.09% in carbon emission index. The environmental impact can be reduced by using renewable electricity (solar, hydroelectric and wind). Methanation process shows favorable environmental performance in comparison with decarbonization process because methanation process largely enhances the CH₄ productivity. This work intends to provide theoretical support for the comprehensive utilization of COG in the coking industry from the life cycle perspective.

Methods for modeling the steam cracking process were reviewed, and the problem of data scarcity faced in industrial realities was described. Facing the massive small dataset modeling requirements in petrochemical industry, an ensemble transfer learning framework was proposed by making full use of the historical production data. First, basic deep learning models were established on a specific working condition with sufficient data. Then, transfer learning techniques were applied to the new working conditions with a small dataset. The process knowledge from the source domain was transferred to the target domain using parameter-based methods. Finally, ensemble learning was introduced to integrate the obtained transfer learning models, resulting in enhanced performance. The performance of entire modeling framework was found to be industrially acceptable on several practical cases, and further layer transferability analysis and SHapley Additive exPlanation (SHAP) feature importance analysis were implemented to provide a better understanding of the model. The results illustrated that the model trained by this method had good accuracy, stability, computational efficiency and interpretability to meet industrial requirements.

The product synthetic gas compositions in methane combined reforming are governed by thermodynamic equilibrium and the relevant coke deposition reactions are also dependent on operation conditions. Hence, quantitative thermodynamic analysis of the influences of operation conditions (feedstock composition, temperature, pressure) on product compositions and coke formation reactions are desirable for process design. In this contribution, the RGibbs reactor in Aspen Plus software was used to calculate Gibbs free energies at varied temperatures, the influence of feeding compositions, temperature and pressure on the compositions of equilibrated reaction mixtures by taking into consideration all relevant reactions. Both methane and carbon dioxide conversions increased as a consequence of temperature increase or pressure decrease, as reflected by the endothermic nature of the volume expansion reaction. When stoichiometric feed [CH₄∶(CO₂+H₂O)=1∶1] was adopted, the influence of different conditions on the composition of reaction products was explored by changing the reaction temperature, pressure and feed composition and the equilibrium conversion of CH₄ and CO₂ increased with increasing temperature and tended to the limit with increasing temperature for all stoichiometric ratios. Meanwhile, methane conversion increased and the carbon deposition increased with increasing carbon dioxide to methane ratios, while methane conversion elevation and suppression of carbon deposition could be achieved by increasing the proportion of steam, even under pressurized operations. The H₂/CO ratios in the product syngas could be manipulated to meet the required low concentrations for unconverted methane. With respect to specified downstream use of syngas, to generated methanol, ethanal, acetic acid and Fischer-Tropsch synthesis, the optimized operation conditions was identified. These calculations provided a thermodynamic basis for selection of bi-reforming conditions, process and catalyst design.