2024年04期目次

  • Advances and prospects of integrated carbon dioxide capture-hydrogenation conversion

    ZHAO Chuanwen;HUANG Pu;GUO Yafei;School of Energy and Mechanical Engineering,Nanjing Normal University;School of Environment,Nanjing Normal University;

    Developing and applying integrated CO_2 capture-hydrogen conversion technology is a key strategy for coping with climate change and achieving carbon peaking and carbon neutrality. Dual functional materials with adsorption and catalytic components are the core technology. In this paper, the main work of the principal national and international research institutions were summarized systematically on synthetic methods, adsorption properties, reaction kinetics, promotion mechanisms, deactivation mechanisms, and applications of dual functional materials for CO_2 capture using in-situ methanation and in-situ reverse water gas shift technologies. An overview of the principal national and international research institutions′latest progress on CO_2 capture-hydrogenation conversion was provided. DFMs are composites with both catalytic and adsorption components. In the selection of catalytic components, noble metal catalysts are highly active but expensive, while Ni-based catalysts are less costly but less reducible and prone to deactivation in oxygen-containing atmospheres. In the selection of adsorption components, metal oxides(e.g., CaO, MgO) and alkali metal carbonates(e.g., Na_2CO_3, K_2CO_3) are the most promising adsorption components due to their high theoretical adsorption capacity, especially MgO and CaO, although they face the challenges of poor actual adsorption capacity and poor cyclic stability. Current studies have focused on enhancing the actual adsorption capacity of MgO by doping with alkali metal molten salts, and improving the cycling performance and sintering resistance of CaO adsorbents by doping with metal additives(e.g., La, Co, Fe, etc.). Kinetic studies have shown that the reaction rate is highly dependent on the H_2 partial pressure and that the average CH_4 yield can be increased by adjusting the timing of adsorption and catalysis. ICCU technology shows promising applications, especially in key areas such as iron and steel, energy, and chemicals. However, a comprehensive assessment of the environmental impact of the technology, especially from a life cycle assessment(LCA) perspective, is essential for a full understanding of the environmental sustainability of ICCU technology and its contribution to carbon reduction. In the future, through continuous research and technological innovation to solve the existing challenges, ICCU technology is expected to achieve significant results in industrialized applications and make important contributions to global carbon emission reduction.

    2024 04 v.30;No.164 [Abstract][OnlineView][HTML全文][Download 6354K]

  • Research progress in solar-driven CH4 and CO2 dry reforming technologies

    XUE Yao;LI Jinhao;YANG Zhijia;WANG Ruoyu;MENG Xianguang;LIN Meng;ZHAO Yufei;State Key Laboratory of Chemical Resource Engineering,College of Chemistry,Beijing University of Chemical Technology;College of Material Science and Engineering,North China University of Science and Technology;Southern University of Science and Technology,Energy Institute for Carbon Neutrality;Quzhou Institute for Innovation in Resource Chemical Engineering;

    With the rapid development of the world economy, energy scarcity and environmental pollution have become focal points of concern. The rapid consumption of fossil fuels has led to the continuous enhancement of the green house effect, causing severe impacts on global environment and climate. Utilizing abundant and clean solar-driven approaches can rapidly target heating supply, converting two major greenhouse gases(CH_4/CO_2) into valuable syngas under mild conditions, thereby significantly reducing the energy consumption and carbon emissions generated by traditional thermocatalytic processes. However, the current solar-driven dry reforming syngas technology still faces several challenges on its path towards industrial application, including low conversion rates of reactant molecules, low efficiency of solar-to-chemical energy conversion, catalyst sintering, and catalyst deactivation caused by carbon deposition. This paper focused on the inherent characteristics of dry reforming reactions and the common issues in the field of solar thermal research, detailing the research progress on photo-thermal dry reforming reactions concerning catalyst preparation, support construction, reactor and system establishment, and optimization. Finally, the prospects and challenges of solar-driven photo-thermal catalytic dry reforming systems were discussed.

    2024 04 v.30;No.164 [Abstract][OnlineView][HTML全文][Download 8324K]

  • Design strategies for copper-based catalysts in electrochemical reduction of carbon dioxide

    ZHENG Yiqun;LI Dun;MIN Yuanyuan;LI Yuyao;HUANG Hongwen;School of Chemistry,Chemical Engineering and Materials,Jining University;College of Materials Science and Engineering,Hunan University;

    With the growth of the global economy, the demand for energy is continuously increasing, which in turn has driven the development and utilization of energy resources. This trend has inevitably led to a steady rise in carbon dioxide(CO_2) emissions. To effectively address this environmental challenge, the technology of electrocatalytic CO_2 reduction(CO_2RR) has emerged and quickly become a focal point in scientific research. This technology not only has the potential to convert CO_2 into fuels and chemicals but also contributes to the storage of renewable energy. Among various catalysts, copper-based catalysts have attracted attention for their ability to efficiently convert CO_2 directly into high-value multi-carbon chemicals, such as ethylene and ethanol. In recent years, there have been significant advancements in the optimization and design of copper-based CO_2RR catalysts, primarily focusing on enhancing catalytic activity, selectivity, and stability. An overview of the recent progress in the research on optimization strategies for copper-based CO_2RR catalysts was provided. Representative strategies were discussed such as crystal facet engineering, alloying treatments, modulation of copper oxidation states, catalyst surface functionalization, and defect engineering, examining how these approaches influence catalytic performance by tuning core parameters like composition, microstructure, morphology, and size, which collectively exerted a synergistic effect on the catalyst performance. Finally, the future prospects of electrocatalytic CO_2RR technology was look forward and the current challenges faced was analyzed.

    2024 04 v.30;No.164 [Abstract][OnlineView][HTML全文][Download 6368K]

  • Progress and prospects of electrocatalytic reduction of CO2 by metal and carbon-based materials

    ZHAO Junbiao;YU Qiuyang;JIANG Yang;HAO Haigang;GAO Rui;School of Chemistry and Chemical Engineering,Inner Mongolia University;

    With the rapid development of global industrialization, the massive use of fossil fuels has led to a sharp increase in carbon emissions, causing serious environmental problems. Therefore, it has become an urgent task to find effective ways to reduce carbon dioxide concentration to curb global warming. Currently, the main strategies to reduce CO_2 include limiting the use of traditional fossil energy sources and converting excess CO_2 into high value-added chemicals. Since economic development is still heavily dependent on fossil energy, there are significant difficulties in simply restricting its use. Therefore, efficient conversion of CO_2 into high value-added chemicals is crucial. Among the many CO_2 conversion technologies(bioreduction, thermochemical hydrogenation reduction, photoelectrochemistry, and electrochemical CO_2 reduction), electrochemical CO_2 reduction stands out due to its high efficiency and good prospects for industrial applications. Based on this, this paper reviewed the current research status of carbon dioxide conversion technology, the principle of electrocatalytic reduction of carbon dioxide, main products, reaction pathways, evaluation parameters, and electrocatalysts of metal-based and non-metallic carbon-based materials, which were developing rapidly at present. The combination of metal-based and non-metal carbon-based materials can improve the catalytic activity of the catalysts and has good research prospects. The following outlooks were proposed for CO_2RR which were the development of new efficient and low-cost catalysts, and the micro-regulation of their morphology and surface active sites, the deepening of the revelation of the reaction mechanism by using in-situ characterization techniques and density-functional theory calculations, the acceleration of the design and development of the assembled devices to promote the industrial application of CO_2RR.

    2024 04 v.30;No.164 [Abstract][OnlineView][HTML全文][Download 4977K]

  • Research progress on catalytic methane and low carbon alcohols production from coke oven gas

    YAN Xiaofeng;ZHOU Hanchao;YAN Zhanhui;QI Dachao;MENG Xianguang;College of Material Science and Engineering,North China University of Science and Technology;College of Yisheng,North China University of Science and Technology;Steel Rolling Operation Department of Shougang Jingtang United Iron and Steel Co.,Ltd.;Enterprise Management Department of Hebei Wenfeng Industrial Group Tangshan Wenfeng Special Steel Co.,Ltd.;

    Metallurgical gas, produced in the metallurgical industry, if mishandled, can lead to serious carbon emissions and air pollution, posing significant challenges for carbon neutrality in the steel industry. Metallurgical gas, especially coke oven gas, serves not only as a fuel but also holds significant chemical resources in its carbon and hydrogen elements. Utilizing co-production processes to manufacture chemicals in the steel industry offers promising solutions to environmental and energy issues such as greenhouse gas emissions, resource wastage, energy consumption, and air pollution. In the catalytic carbon sequestration process, the catalytic production of methane and low-carbon alcohols using coke oven gas has attracted considerable attention due to its advantages in process efficiency and operational feasibility. Firstly, the process conditions and reaction mechanisms for catalytic methane and methanol production from coke oven gas were introduced, along with discussions on the influence of factors such as additives and carriers on the catalyst′s resistance to coking and stability. Secondly, the importance of constructing dual active centers with high activity and stability in the design of catalysts for the production of other low-carbon alcohols from coke oven gas was emphasized, elucidating the impact mechanisms of precursor structure and additives on the modified Fischer-Tropsch synthesis catalysts and modified methanol catalysts. Regarding reaction conditions, methane conversion requires higher temperatures, while methanol production requires higher pressures. In terms of process complexity, methane conversion is the simplest, whereas formic acid production is the most complex. In terms of hydrogen consumption, formic acid production does not require hydrogen consumption, while methane conversion consumes the most hydrogen. Carbon sequestration co-production should be carried out adaptively, considering various practical factors and product economic benefits, to continuously promote catalytic carbon reduction, driving innovation in carbon sequestration co-production technology and the development of clean energy technologies.

    2024 04 v.30;No.164 [Abstract][OnlineView][HTML全文][Download 7558K]

  • Co-thermal in situ hydrogenation of cement raw material to synthetic gas

    ZHANG Weitao;YU Shaokang;XU Ming;DONG Meng;GUO Dabing;YANG Yusen;SHAO Mingfei;DUAN Xue;State Key Laboratory of Chemical Resource Engineering,Beijing University of Chemical Technology;College of Chemistry,Chemical Engineering and Resource Utilization,Northeast Forestry University;Quzhou Resources Chemical Innovation Research Institute;

    The cement industry is the world′s third largest energy consumer and second largest CO_2 emitter, accounting for 7% of global CO_2 emissions. Cement raw material(mixture of CaCO_3, Fe_2O_3, Al_2O_3 and SiO_2) was calcined at high temperature(>900 ℃) to obtain cement clinker, which had high energy consumption and releases a huge amount of CO_2. Based on the dual-carbon background, this paper prepared cement raw material by ball milling method, adopted the innovative strategy of carbonate co-thermal coupling in situ hydrogenation reduction, and realized the in situ hydrogenation of cement raw material to produce CO at 700 ℃. The selectivity reaches 94.8%, and the CO generation rate reaches 0.76 mmol/min. The pyrolysis temperature of carbonate is significantly reduced, CO_2 emission is inhibited, and uniformly porous CaO particles are obtained. X-ray powder diffraction(XRD), specific surface area(BET), scanning electron microscopy(SEM), Raman spectroscopy(Raman) and in situ diffuse Fourier transform infrared spectroscopy(In situ DRIFTS) and other characterization methods were used to investigate the effects of reaction temperature and different ponents(Fe, Si and Al) on the hydrogenation performance of carbonate. The results show that Fe helps to improve the selectivity of CO products and produce a small amount of methane, and the addition of Si and Al elements reduces the rate of carbonate hydrogenation. In situ DRIFTS indicate that CO generation from cement raw material hydrogenation may follow the formate intermediate species mechanism. Synthetic gas is prepared by in situ hydrogenation of cement raw materials through co-thermal coupling. This study can reduce consumption and increase efficiency at the source of cement industry, and provide a new strategy and theoretical basis for the preparation technology of low-carbon cement clinker.

    2024 04 v.30;No.164 [Abstract][OnlineView][HTML全文][Download 7708K]

  • Kinetics and process flow simulation and optimization of CO2 hydrogenation to methanol

    QIU Haoshu;SONG Lei;YANG Qiulin;YUE Hairong;LIANG Bin;School of Chemical Engineering,Sichuan University;Sichuan Development Environmental Science and Technology Research Institute Co.,Ltd;

    Carbon capture, utilization and storage(CCUS) technology has received increasing attention in order to cope with environmental problems such as global warming. CO_2 hydrogenation to methanol is an important CCUS technology, realizing both CO_2 resource utilization and chemical storage of renewable energy. In order to explore and optimize the process of CO_2 hydrogenation to methanol, the catalytic performance of commercial Cu-ZnO/Al_2O_3 catalyst in the process of CO_2 hydrogenation to methanol was tested in a fixed bed reactor. The catalytic effects of the catalyst at 448.15-543.15 K, 1-3 MPa, and 3-9 molar ratio of H_2 and CO_2 were investigated. The results show that the CO_2 conversion rate increases with the increase of reaction temperature. Methanol selectivity is mainly affected by temperature and hydrogen/carbon molar ratio: the higher the temperature is, the lower the methanol selectivity is, and the higher the hydrogen/carbon molar ratio is, the higher the methanol selectivity is. Both CO_2 conversion and methanol selectivity are enhanced by increasing pressure. Taking formate hydrogenation step as the rate control step of the reaction, the reaction kinetic model of the catalyst used in the process of CO_2 hydrogenation to methanol was derived and established on the basis of LHHW kinetic theory. The model optimization function was constructed in MATLAB to solve the model parameters, and the reaction kinetic equation was obtained. The activation energies of the two reactions are 42.4 and 122.1 kJ/mol, respectively. The recycling process of CO_2 hydrogenation to methanol was established in Aspen Plus software, and the energy consumption of the recycling process was optimized by increasing the heat transfer between streams. The heat of the reactor outlet gas was recovered by a shell and tube heat exchanger for the preheating of the feedstock gas, which reduced the energy consumption of the preheating process by 86.2%. At the same time, the sensitivity analysis of flash separation temperature and raw material gas preheating temperature was carried out, and the final choice of flash separation temperature was 323.15 K, raw material gas preheating temperature was 498.15 K. The process product is refined methanol with molar purity above 99.5% and methanol recovery >99%. The optimal methanol production energy consumption is 4.84 GJ/t.

    2024 04 v.30;No.164 [Abstract][OnlineView][HTML全文][Download 2737K]

  • Potential of CO2 emission reduction of coal gasification combined with green electricity

    SUN Yi;GUO Xiaojin;XU Xiang;Key Laboratory of Advanced Energy and Power,Institute of Engineering Thermophysics (IET),Chinese Academy of Sciences(CAS);University of Chinese Academy of Sciences;Jiangsu Zhongke Research Center for Clean Energy and Power;

    For the processes to produce coal-based chemicals using coal gasification processes, combining with green electricity is an effective method to achieve CO_2 emission reduction because not only the CO_2 emissions caused by combustion of coal to provide needed heat in gasifiers can be eliminated but also the higher hydrogen to carbon ratio(H/C) of synthesis gas can be obtained and the CO_2 emissions in water-gas-shift unit can be reduced. The models of different conventional gasifiers were simulated and verified, and the corresponding green electric heating gasifiers were simulated. The trends on the composition of the gaseous products and the H/C of the syngas were simulated, and the influences on the products by temperature, sorts of coals, and sequence of reactor models were analyzed. Furthermore, the trends of H/C with temperature are investigated and the potential of CO_2 emission reduction are calculated. It is found that the CO_2 emissions of the reactors combining with green electricity decrease by 12.63%(fixed bed), 11.01%(entrained flow bed), 9.23%(transport bed) and 5.12%(fluidized bed), respectively. Besides, the H/C shows an upward trend. Temperature has a significant impact on the composition of syngas, and the reactors for decoupling pyrolysis and gasification reactions to some extent affect the composition of syngas. When the temperature is below 1 500 K, the H/C decreases with the increase of temperature. When the temperature is above 1 500 K, the hydrogen to carbon ratio slowly increases with the increase of temperature. Decoupling pyrolysis and operating under lower pressure can help to achieve a higher H/C and lower CO_2 emission, and the gasifiers operating under more moderate conditions have more potential of CO_2 emission reduction. The efficiency advantage of the fixed bed coupling with green electricity is obvious. Considering the technical difficulties of high-temperature reactors coupled with green electricity, fixed bed, fluidized bed, and transport bed reactors coupled with green electricity are more feasible.

    2024 04 v.30;No.164 [Abstract][OnlineView][HTML全文][Download 4185K]

  • Preparation of ultra-thin and ultra-small nickel-iron layered double hydroxide by acoustic levitation

    JIA Xiaodan;LI Jinlong;ZHANG Shaobing;JIA Jinxin;ZHAO Shunsheng;YANG Zaiwen;YANG Zheng;LIU Xiangrong;College of Chemistry and Chemical Engineering,Xi′an University of Science and Technology;Key Laboratory of Coal Resources Exploration and Comprehensive Utilization,Ministry of Natural Resources;

    The development of efficient and low-cost clean energy contributes to the reduction of CO_2 emissions. Hydrogen and oxygen production from electrocatalytic water splitting may be a promising solution to the future demand for clean energy. Among many nanomaterials, ultrathin two-dimensional materials have shown excellent performance in electrocatalytic reactions due to the fact that they can expose more active sites and have higher specific surface area. Nickel-iron layered double hydroxide(NiFe-LDH) is a very promising transition metal electrocatalytic catalyst for oxygen evolution reaction(OER). Therefore, Ni_xFe_1-LDH(x=1,2,3) precursors were synthesized by hydrothermal method, then the ultra-thin and ultra-small LDH nanosheets were quickly synthesized by acoustic levitation. The acoustic levitation method utilizes the high-intensity acoustic radiation force generated between the emitting and reflecting ends of ultrasound to counteract the gravity of the sample, which in turn levitated the sample. The high acoustic intensity standing wave formed by repeated superposition of ultrasound waves makes it easier to realize the rapid preparation of ultra-thin and ultra-small nanomaterials. It is found that the Ni_1Fe_1-LDH precursor could be successfully exfoliated into ultra-thin and ultra-small hydrotalcite nanosheets with only 20 μL formamide within 20 min by acoustic levitation. The transverse size of the Ni_1Fe_1-LDH precursor is 1 500 nm and the thickness is 25.66 nm. The ultra-thin and ultra-small Ni_1Fe_1-LDH-20 min transverse size is 10 nm, and the thickness is as low as 0.649 nm. It shows excellent OER catalytic performance. For different molar ratios of nickel-iron hydrotalcites, with the increasing of the acoustic levitation time, the OER properties is improved. When the current density reaches 10 mA/cm~2, the overpotential of Ni_1Fe_1-LDH-20 min is 309 mV, compared to the overpotential of 673 mV of Ni_1Fe_1-LDH precursor, it decreases by 364 mV. The tafel slope decreased from 137 to 67 mV/dec, and the electrochemically active surface area was increased by 2.4 times. Compared with other transition metal-based catalysts, it demonstrates excellent performance in OER.

    2024 04 v.30;No.164 [Abstract][OnlineView][HTML全文][Download 6013K]

  • Properties and mechanism of carbon dioxide mineralization portland cement paste

    MA Chao;WANG Tao;WU Bing;YI Zhenwei;State Key Laboratory of Clean EnergyUtilization,Zhejiang University;State Grid Zhejiang Electric PowerCo.,Ltd.,Economic and Technological Research Institute;

    Carbon dioxide capture, utilization and storage(CCUS) technology has been paid more and more attention as an important technical means to deal with the global climate and environmental crisis. Using the mineralization reaction of cement-based materials to absorb carbon dioxide can not only achieve the permanent storage of CO_2 and improve the mechanical properties of the products, but also reduce the amount of cement in concrete, thus reducing a large amount of carbon dioxide emissions. In this paper, using OPC paste as raw material, the effects of different factors(temperature, CO_2 content and CaCO_3 doping amount) on the carbon sequestration and mechanical properties of cement were systematically studied, and the composition, micro-morphology and micro-pore structure of mineralization products were tested and analyzed. The interaction mechanism of temperature, CO_2 and CaCO_3 on the mineralization process of OPC paste was summarized, and the micro reaction model of carbon dioxide mineralization OPC paste with calcium carbonate was summarized. The results show that it possesses 77.99% carbon sequestration at 70 ℃ and 6.7% strength gain at 28 days, and the optimal addition of CO_2 is 0.5%, and the addition of CaCO_3 is able to increase the carbon sequestration and strength of OPC slurry, and the CO_2 doping can be increased to 3% while maintaining the strength gain when the CaCO_3 addition is 10%.

    2024 04 v.30;No.164 [Abstract][OnlineView][HTML全文][Download 4609K]

  • Investigation on high-purity CaCO3 by ammonium sulfate enhanced gypsum dissolution mineralization

    LIU Yanru;ZHONG Shan;TANG Siyang;YANG Ke;SONG Lei;LI Hongjiao;LIANG Bin;School of Chemical Engineering,Sichuan University;Sichuan Development Environmental Science and Technology Research Institute Co.,Ltd.;Sichuan Provincial Industrial Wastewater Pollution Control and Low Carbon Resource Utilization Engineering Technology Research Center;Research Institute of New Energy and Low Carbon Technology,Sichuan University;

    In recent years, the technology of using solid waste gypsum to mineralize CO_2 and co-produce CaCO_3 and ammonium sulfate has received widespread attention. However, due to the complex composition of solid waste gypsum, difficult separation and purification processes, and the difficulty in balancing cost and mineralization products quality, the gypsum mineralization technology is unable to achieve large-scale industrial utilization. Therefore, calcium sulfate and phosphogypsum were used as raw materials and proposed an indirect mineralization process, which firstly using ammonium sulfate solution, a liquid phase product of gypsum mineralization, to enhance the dissolution and leaching of calcium sulfate, followed by liquid-solid separation, and then mineralized with the calcium sulfate solution. The effects of ammonium sulfate concentration and dissolution leaching time on the dissolution strengthening process were experimentally investigated, and the effects of ammonium concentration, temperature and mineralization reaction time on the mineralization process and mineralization products were discussed as well. The optimized dissolution and mineralization process conditions were determined, basing on which the indirect mineralization process of phosphogypsum was further studied. The experimental results show that, compared with direct mineralization, indirect mineralization can increase the purity of CaCO_3 products from 82.2% to 98.6%, and can decrease the particle size D_(50) from 22.00 μm to 10.98 μm. The indirect mineralization process can effectively strengthen the dissolution and leaching process of gypsum, avoid the introduction of external media, and prepare high-purity light CaCO_3. The present research can provide basic support for the economic application of CO_2 technology for solid waste gypsum mineralization.

    2024 04 v.30;No.164 [Abstract][OnlineView][HTML全文][Download 3732K]

  • Preparation and CO2 adsorption performance of a phosphine-containing porous organic polymer supported magnesium oxide

    TIAN Tian;ZHANG Xueqi;WANG Yuqing;YU Gewen;DING Jian;HE Wenxiu;Laboratory of Carbon Capture and Efficient Utilization,School of Chemistry and Chemical Engineering,Inner Mongolia University of Science & Technology;Inner Mongolia Key Laboratory of Coal Chemical Engineering & Comprehensive Utilization,Inner Mongolia University of Science & Technology;

    MgO adsorbent has been widely used in the field of CO_2 adsorption due to its advantages of low cost, wide source and low regenerative energy consumption, but its adsorption performance is limited by its low surface ratio. In this paper, a phosphine-containing porous organic polymer POL-PPH_3 with high surface area and hierarchical pore structure was used as a carrier, and POL-PPH_3-loaded MgO adsorbent(MgO/POL-PPH_3) was prepared by impregnation-calcination and ultrasonic calcinations to obtain the MgO adsorbent(MgO/POL-PPH_3) for CO_2 capture. Effects of preparation conditions such as preparation method, calcination temperature and calcination time on the CO_2 adsorption performance on MgO/POL-PPH_3 adsorbents were investigated. It is found that the impregnation calcination method is superior to the ultrasonic calcination method, and the CO_2 adsorption capacity on the MgO/POL-PPH_3 samples gradually decreases with the increase of calcination temperature and calcination time. The optimum CO_2 adsorption capacity of 0.55 mmol/g on MgO/POL-PPH_3-300-1 adsorbent is obtained when the impregnation calcination method is used with a calcination temperature of 300 ℃ and a calcination time of 1 h. In the simulated flue gas with a composition of 12% CO_2 and the rest of nitrogen, the CO_(2 )adsorption capacity of 0.02 mmol/g on the MgO/POL-PPH_3-300-1 adsorbent is obtained. Under the conditions of adsorption at 200 ℃ for 60 min and desorption at 370 ℃ for 15 min, the CO_2 adsorption capacity of this adsorbent remains unchanged after five times of stable recycling. The structure-property relationship of CO_2 adsorption on MgO/POL-PPH_3 adsorbent was elucidated by combining N_2 physical adsorption, thermogravimetric, FT-IR, XRD, SEM-EDX and other characterization methods. Kinetic modelling analysis of the CO_2 adsorption behaviours on the three adsorbents obtained at different calcination temperatures by impregnation calcination method is dominated by physical adsorption, whereas those of the three adsorbents obtained at different calcination times, including the MgO/POL-PPH_3-300-1 adsorbent, are dominated by chemical adsorption. The high specific surface area and hierarchical pore structure are conducive to the exposure of more active sites and the transport and diffusion of CO_2, which in turn increases the CO_2 adsorption capacity of the MgO/POL-PPH_3 adsorbent, and the high dispersion of MgO on the support is also benificial to the enhancement of the contact with CO_2 to accelerate the CO_2 adsorption rate.

    2024 04 v.30;No.164 [Abstract][OnlineView][HTML全文][Download 4771K]

  • Carbon emission reduction potential and life cycle assessment of calcium carbon slag utilisation

    LIAO Xueyan;CHENG Huaigang;QIAN Aniu;PAN Zihe;CHENG Fangqin;Engineering Research Centre for CO2 Emission Reduction and Resource Utilisation,Ministry of Education,Institute of Resources and Environmental Engineering,Shanxi University;Huairou Laboratory Shanxi Research Institute;

    Recycling of calcium carbide slag in areas such as building materials, environmental treatment and chemical products can realize the utilization of industrial waste slag and carbon dioxide emission reduction. Under the dual-carbon background, it is particularly important to analyse the carbon reduction potential of calcium carbide slag in terms of carbon sequestration and its recycling pathway. The particle size distribution and chemical composition of calcium carbide slag in the representative production areas were counted in detail, the theoretical carbon sequestration was calculated based on the calcium oxide content in each slag, the carbon emission reduction effect of various recycling pathways of calcium carbide slag was analysed systematically as well as the specific implementation steps in the life-cycle assessment(LCA), and the application cases of LCA in the field of calcium carbide slag were introduced. The calculation results show that the theoretical carbon sequestration of calcium oxide is positively correlated with the content of calcium oxide of calcium carbide slag. The calcium oxide mass fraction of calcium oxide in calcium carbide slag from Xinjiang and Hebei are both about 90%, and the calcium oxide mass fraction of calcium carbide slag from Shandong is lower, about 61%, and the theoretical carbon sequestration of calcium carbide slag from six origins, including Shandong and Xinjiang, floats in the range of 0.48 to 0.72 t/t(electrochemical slag). In the field of calcium carbide slag recycling, calcium carbide slag, whether it is a substitute for limestone raw materials for the production of cement, bricklaying, calcium chloride and calcium carbonate and other construction and chemical products, or its alkaline characteristics for flue gas desulphurisation and industrial wastewater treatment, according to the respective differences in the scale of the industry can be different degrees of reduction of carbon dioxide emissions, to achieve the purpose of carbon emission reduction. Among them, calcium carbide slag in the field of building materials application is mature, the production scale is large, so the total amount of carbon emissions reduction is larger, on behalf of the enterprise can reduce carbon dioxide emissions by 10 000 t per year on average. Four case analyses using life cycle assessment to calculate carbon emissions from recycling of calcium carbide slag show that 1 t of cement clinker made from calcium carbide slag emits 669 kg of CO_2. The CO_2 emissions of 1 t of light calcium carbonate made from calcium carbide slag in NH_4Cl and( NH_4)_2SO_4 leaching systems are comparable, 308.21 and 300.7 kg, respectively, and the CO_2 emissions of 1 t of cemented products made from calcium carbide slag are the lowest, about 151.7 kg, and the CO_2 emissions of 1 t of cemented products made from calcium carbide slag are the lowest, about 151.7 kg. The lowest carbon emission is about 151.11 kg. It is assumed that the drying pre-treatment process of cement produced by calcium carbide slag consumes a lot of energy, which leads to the high CO_2 emission. Compared with cemented products, calcium carbonate prepared by calcium carbide slag needs to be added with chemical reagents, such as NH_4Cl or(NH_4)_2SO_4, and the indirect emission brought by the increase in the raw and auxiliary materials makes the former′s carbon emission greater. The net CO_2 emission of calcium carbide slag-cemented products is-301.47 kg/t(cemented products), and the net CO_2 emission of calcium carbide slag in NH_4Cl and(NH_4)_2SO_4 leaching system to make 1 t light calcium carbonate is-157.5 and-139.3 kg, respectively. It can be seen that calcium carbideslag recycling in the field of cemented products is the best carbon emission reduction. It is suggested that the carbon emission reduction of calcium carbide slag can be studied from this aspect. If the study of carbon emission reduction in the field of calcium carbonate slag cement/calcium carbonate is carried out, it can start from the optimisation of the drying and treatment process of calcium carbonate slag and the addition of raw and auxiliary materials to formulate targeted carbon emission reduction plans.

    2024 04 v.30;No.164 [Abstract][OnlineView][HTML全文][Download 4384K]

  • Cross-industry coupling carbon dioxide recycling technology in chemical and metallurgy

    LI Shuangde;LI Zhenrong;DONG Xiao;CHEN Wei;LIU Yifan;LI Shaopeng;CHENG Jingcai;LI Huiquan;CHEN Yunfa;Institute of Process Engineering,Chinese Academy of Sciences;University of Chinese Academy of Sciences;Institute of Coal Chemistry,Chinese Academy of Sciences;Shanghai Advanced Research Institute,Chinese Academy of Sciences;

    The dual carbon strategy is a major national strategy, which will also promote the high-quality and sustainable development of the national economy. The time of China′s carbon peak to carbon neutrality is short and the task is heavy. Carbon dioxide emissions from chemical and metallurgy in China are about 3.6 billion tons per year, accounting for about 36% of the country′s industrial carbon emissions. In addition, waste gas, solid waste, waste heat generation from chemical and metallurgical possess large heap stock, difficult to use, low recycling rate. The development of low-carbon transformation and revolution of chemical and metallurgy is the fundamental guarantee for the realization of the dual carbon goal in China′s industrial field. Most of China′s chemical and metallurgy are mature processes of more than 100 years, and the carbon reduction capacity is limited only through raw material and fuel substitution, together with green process transformation, so it is urgent to carry out cross-industry coupling and recycling technology of chemical and metallurgy, which can further promote carbon reduction in these industrial field. Most of China′s chemical and metallurgy are isolated, non-cyclic continuous processes, which will cause the difficult of cross-industry coupling and recycling. In response to the above problems, the current situation of the control for carbon emission and national strategic for the realization of the dual carbon goal in chemical and metallurgy were firstly analyzed. Secondly, three strategies for carbon reduction and efficiency improvement were proposed: The coupling of waste gas and waste heat for transferring into high-quality gas, the coupling of waste gas and waste gas to produce high-end chemicals, and the coupling of waste gas and solid waste to produce low-carbon based materials. Finally, in order to provide support for the low-carbon and green development of industry, the specific technology for cross-industry coupling carbon dioxide recycling of chemical and metallurgy were proposed.

    2024 04 v.30;No.164 [Abstract][OnlineView][HTML全文][Download 1936K]

  • Preparation of encapsulated Ni-based catalyst and its performance in-situ upgrading of coal pyrolysis tar

    JIA Peng;WANG Mingyi;WANG Yugao;WANG Junwen;WANG Jiaofei;College of Chemical Engineering and Technology,Taiyuan University of Technology;Huayang New Material Technology Group Co.,Ltd.;State Key Laboratory of High-Efficiency Utilization of Coal and Green Chemical Engineering,Ningxia University;

    In order to realize the in-situ upgrading process of coal pyrolysis tar, Ni-based catalysts were prepared by in-situ encapsulation method and impregnation method respectively, and the effects of these two catalysts on the in-situ catalytic upgrading of pyrolysis tar were investigated. Compared with no catalyst, Ni/HZSM-5 with Ni content of 2% can increase the yield of light components in tar from 5.8% to 6.9%, while Ni@HZSM-5 with the same Ni content can increase the yield of light tar to 7.6%.The influence of Ni/HZSM-5 and Ni@HZSM-5 catalysts on the yield of each component of tar was further analyzed. The results shows that both catalysts significantly reduces the heavy components in tar, and the asphaltene yield decreases from 5.4% to 1.3% and 2.0%, respectively. However, compared with Ni/HZSM-5, Ni@HZSM-5 increases the yield of light oil and phenol oil by 38.5% and 25.5%, respectively, and naphthalene oil also increases to a certain extent, indicating that the Ni based catalyst prepared by encapsulation method can maximize the retention of light components in tar. This is because in Ni/HZSM-5, both tar cracking and activation of hydrogen-rich components in pyrolysis gas occur on the Ni surface, which promotes the activation of hydrogen-rich gas and also causes excessive tar cracking. The Ni in Ni@HZSM-5 is mainly distributed in the pore of molecular sieve. Its excellent shape selection catalytic performance enables hydrogen-rich gas molecules to enter into the HZSM-5 and contact with Ni, producing hydrogen-rich free radicals such as ·H and ·CH_x, while large molecules in tar cannot enter into the pore of molecular sieve. The cracking can only occur on the acid site on the outer surface of HZSM-5, avoiding the participation of metal Ni in tar cracking, so as to regulate the amount of tar cracking fragments and hydrogen-rich free radicals, so as to achieve the balance of hydrogen and carbon in the system. As a result, the excessive cracking of tar fragments is effectively avoided and the yield of light tar is improved.

    2024 04 v.30;No.164 [Abstract][OnlineView][HTML全文][Download 2970K]

  • Synergetic effect during co-pyrolysis of low-rank coal and polypropylene

    WANG Xueting;ZHONG Mei;DAI Zhenghua;JIN Lijun;ZHOU Qi;YANG Xiao;School of Chemical Engineering and Technology Xinjiang University,State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources,Xinjiang Key Laboratory of Coal Clean Conversion & Chemical Engineering;State Key Laboratory of Fine Chemicals,Institute of Coal Chemical Engineering,School of Chemical Engineering,Dalian University of Technology;National Energy Technology &Equipment Laboratory of Coal Utilization and E

    The coal reserves in Xinjiang are rich, with a high proportion of low-rank coal. Among them, the coal in Hami region is generally characterized by high volatile content, which is suitable for the tar and gas by pyrolysis. However, there are many problems with pyrolysis tar, such as high content of heavy components, high viscosity and easy to carry dust. Therefore, how to reduce the content of heavy components in tar and improve the quality of tar is the key to realize high value utilization. Plastics and coal have similar pyrolysis intervals but the H/C atoms of plastics is much higher than that of coal. The hydrogen-rich components produced during pyrolysis could promote the primary pyrolysis reaction of coal or inhibit the cross-linking phenomenon during coal pyrolysis. Volatiles interaction exists during co-pyrolysis of coal and plastics, which is closely related to the contact mode of raw materials. The co-pyrolysis of polypropylene(PP) and Naomaohu coal(NMH) were investigated by combing TG, TG-MS and TG-FTIR-GC/MS. TG-MS results show main pyrolysis temperature range of the two rapid decomposition stages basically coincided, and the formation of ·CH_3 during PP pyrolysis. When PP layer is placed on top of NMH layer with different mass ratios, the weight loss characteristics and the volatiles evolution of NMH exhibit an obvious difference. The strongest synergy appears on the mass ratio of 8∶2 for NMH and PP during the co-pyrolysis process. TG-FTIR-GC/MS experimental results reveal that the synergistic effect of NMH and PP changes the release form of oxygen because the radicals from PP pyrolysis facilitates the cleavage of covalent bonds of NMH, leading to the increase of CO and H_2O yields but the decrease of CO_2 yield. Compared with the theoretical calculated values, the relative content of alkene and alcohols increases by 30.58% and 16.18%, while those for CO_2 and alkanes decreases by 8.89% and 14.43%, respectively. The activation energy of co-pyrolysis calculated by Flynne-Walle-Ozawa is 6.8 kJ/mol lower than the theoretical value, confirming that PP is conducive to the release of NMH volatiles.

    2024 04 v.30;No.164 [Abstract][OnlineView][HTML全文][Download 4001K]

  • Products characteristics and char gasification reactivity of Naomaohu coal hydropyrolysis

    GUO Erguang;WANG Guijin;CHEN Jiaqi;JIN Lijun;HU Haoquan;Institute of Coal Chemical Engineering,School of Chemical Engineering,Dalian University of Technology;

    The pyrolysis experiments of Naomaohu coal(NMH) at atmospheric pressure and 1.5 MPa H_(2 )and N_2 were carried out in a pressurized fixed-bed reactor. The products yield and composition and char structure under H_2 and N_2 were comparatively investigated by various characterization methods. The CO_2 gasification reactivity of char was studied by a thermogravimetric analyzer. The results indicate that pyrolysis of coal in pressurized H_2 can effectively increase the yield of CH_4 and C_2-C_3, from 53.5 and 16.6 mL/g in atmospheric N_2 to 345.6 and 20.8 mL/g in pressurized H_2, respectively, during the coal pyrolysis at 800 ℃. Tar yield and quality is also effectively improved. Compared coal pyrolysis at 600 ℃ under 1.5 MPa H_2 with that under atmospheric pressure N_2, the tar yield increases from 19.3% to 22.8%, the aliphatic hydrocarbon content decreases from 35.5% to 14.8%, the monocyclic aromatic hydrocarbon content increases from 8.3% to 28.9%, and the light tar content and yield increases to 95% and 21.8%, respectively. The results of N_2 adsorption and Raman spectroscopy show that the specific surface area and pore volume of the char in pressurized hydropyrolysis increase from 40 m~2/g and 0.05 cm~3/g in atmospheric N_(2 )to 289 m~2/g and 0.16 cm~3/g, and the pore structure is significantly developed. This is beneficial to the CO_2 gasification reaction of char. The graphitization degree and the proportion of large aromatic ring increase, which is not conducive to the gasification reaction of char. The thermogravimetric analysis results show that the gasification reactivity of char from pressurized hydropyrolysis is significantly higher, which indicates that pore structure plays a main role in the influence on the CO_2 gasification reactivity of the char.

    2024 04 v.30;No.164 [Abstract][OnlineView][HTML全文][Download 6498K]

  • Influencing factors of coal liquefaction residue induced polycondensation to prepare metallurgical coke

    LUO Huafeng;LI Tongda;WEI Zheng;QIAO Yuandong;School of Coal Engineering,Shanxi Datong University;

    The asphaltene and heavy oil contained in coal liquefaction residue can generate a large number of free radicals during pyrolysis. If they cannot be stabilized and polycondensation in time, they will be transformed into a large number of tar and gas, forming pore structure, affecting the density of metallurgical coke. Therefore, a certain amount of additives to induce high efficiency polycondensation was introduced, polymer density was improved, high-quality metallurgical coke was prepared after carbonization. The effects of different additives(furfural, methanol, furan and hydroxyacetone), temperature(350, 400, 450, 500 and 550 ℃), residence time(0, 30, 60 and 120 min) and addition amount(0, 4, 8 and 16 g) on the polycondensation rate, structural properties, density and thermal stability of the prepared polymer were systematically studied. The optimum experimental conditions for induced polycondensation of coal liquefaction residue were obtained. Under the optimal conditions, the surface morphology, microcrystal structure and element changes of the prepared polymer and carbonization were investigated respectively, and the induced polycondensation mechanism of coal liquefaction residue was obtained. The results show that the additive(furfural) have the best effect on inducing polycondensation, followed by hydroxyl acetone. Therefore, the superior additive should contain at least one aldehyde or ketone group. The different additives can promote the polycondensation of coal liquefaction residue and increase the specific surface area, pore volume, average pore size and true density of the polymer. The temperature and residence time have great influence on the thermal stability and surface properties of coal liquefaction residue/furfural polymer. The increasing temperature and residence time can promote the phenolic groups and H of aromatic compounds in the coal liquefaction residue to participate in the polycondensation reaction and improve the polycondensation′ degree of polymer. The coal liquefaction residue/furfural(coke) is lamellar dense and contains more amorphous carbon.

    2024 04 v.30;No.164 [Abstract][OnlineView][HTML全文][Download 2652K]

  • Chemical regulation of FeSO4/K2S2O8 on micro-fine high-viscosity coal slime

    WU Jinchuan;FAN Minqiang;LIU Airong;YANG Hongli;BI Haiyi;College of Mining Engineering,Taiyuan University of Technology;

    Coal slime water containing a large number of high-ash slime usually adds a large amount of polyacryla-mide( PAM) in the sedimentation and concentration stage, so that the underflow of the thickener will be more viscous, resulting in prolonged pressure filtration cycle. In this paper, by adding inorganic salts FeSO_4 and K_2S_2O_8 solution to the slurry containing a large amount of polyacrylamide, the slime pressure filtration test under different dosage of reagents was carried out. The viscosity of PAM solution and PAM containing slurry before and after the addition of reagents, the surface electrical properties of particles and the morphology of particle agglomeration were tested and analyzed, and the mechanism of FeSO_4 and K_2S_2O_8 was discussed. The results show that FeSO_4 and K_2S_2O_8 can degrade the macromolecular polypro-pylene aminoamide in the pulp, reduce the viscosity of the pulp, form loose large flocs, improve the pressure filtration speed, shorten the pressure filtration cycle, and reduce the water content of the filter cake. Because FeSO_4 has both chemical degradation of PAM and aggregation of fine particles, its filter aid effect is better than K_2S_2O_8. When the dosage of FeSO_4 is 1 000 g/t, the slurry viscosity is reduced by 482 mPa·s, the pressure filtration time is shortened by 70.97%, and the moisture content of the filter cake is reduced by 2.31%. FeSO_4 is cheap and easy to obtain, which can play an active role in the dewatering and filtra-tion of high mud coal slime in coal preparation plant.

    2024 04 v.30;No.164 [Abstract][OnlineView][HTML全文][Download 4121K]
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