Zeolite derived from coal-based solid wastes(coal gangue and coal fly ash)can overcome the environmental problems caused by coal-based solid wastes and achieve valuable utilization.In this paper,the physicochemical pr...Zeolite derived from coal-based solid wastes(coal gangue and coal fly ash)can overcome the environmental problems caused by coal-based solid wastes and achieve valuable utilization.In this paper,the physicochemical properties of coal gangue and coal fly ash are introduced.The mechanism and application characteristics of the pretreatment processes for zeolite synthesis from coal-based solid wastes are also introduced.The synthesis processes of coal-based solid waste zeolite and their advantages and disadvantages are summarized.Furthermore,the application characteristics of various coal-based solid waste zeolites and their common application fields are illustrated.Finally,we propose an alkaline fusion-assisted supercritical hydrothermal crystallization as an efficient method for synthesizing coal-based solid waste zeolites.In addition,more attention should be given to the recycling of alkaline waste liquid and the application of coal-based solid waste zeolites in the field of volatile organic compound adsorption removal.展开更多
To understand the migration mechanisms of phosphorus(P)during coal-based reduction,a high-phosphorus oolitic iron ore was reduced by coal under various experimental conditions.The migration characteristics and kinetic...To understand the migration mechanisms of phosphorus(P)during coal-based reduction,a high-phosphorus oolitic iron ore was reduced by coal under various experimental conditions.The migration characteristics and kinetics of P were investigated by a field-emission electron probe microanalyzer(FE-EPMA)and using the basic principle of solid phase mass transfer,respectively.Experimental results showed that the P transferred from the slag to the metallic phase during reduction,and the migration process could be divided into three stages:phosphorus diffusing from the slag to the metallic interface,the formation of Fe P compounds at the slag metal interface and P diffusing from the slag metal interface to the metallic interior.The reduction time and temperature significantly influenced the phosphorus content of the metallic and slag phases.The P content of the metallic phase increased with increasing reduction time and temperature,while that of the slag phase gradually decreased.The P diffusion constant and activation energy were determined and a migration kinetics model of P in coal-based reduction was proposed.P diffusion in the metallic phase was the controlling step of the P migration.展开更多
NaY zeolites were in-situ synthesized from coal-based kaolin via thehydrothermal method. The effects of various factors on the structure of the samples were extensivelyinvestigated. The samples were characterized by N...NaY zeolites were in-situ synthesized from coal-based kaolin via thehydrothermal method. The effects of various factors on the structure of the samples were extensivelyinvestigated. The samples were characterized by N_2 adsorption, XRD, IR and DTG-DTA methods, andthe results show that the crystallization temperature and amount of added water play an importantrole in the formation of the zeolite structure. The 4A and P zeolites are the competitive phasepresent in the resulting product. However, NaY zeolites with a higher relative crystallinity,excluding impure crystals and the well hydrothermal stability, can be synthesized from coal-basedkaolin. These zeolites possess a larger surface area and a narrow pore size distribution, and thismeans that optimization of this process might result in a commercial route to synthesize NaYzeolites from coal-based kaolin.展开更多
In this study,the Heishan coal was used to prepare a series of activated carbon(AC)samples via a vapor deposition method.The effects of the Fe(NO_(3))3/coal weight ratio on the physicochemical properties of the activa...In this study,the Heishan coal was used to prepare a series of activated carbon(AC)samples via a vapor deposition method.The effects of the Fe(NO_(3))3/coal weight ratio on the physicochemical properties of the activated carbon were systematically investigated,and the AC samples were analyzed by the N2 adsorption-desorption technique,the scanning electron microscopy,the X-ray diffraction,the Raman spectroscopy,and the Fourier transform infrared spectroscopy.Furthermore,the adsorption properties of ethyl acetate were investigated.The results indicated that as the Fe(NO_(3))3/coal mass ratio increased from 1:8 to 1:2,the specific surface area,the total pore volume and the micropore volume initially increased and then decreased.The specific surface area increased from 560.86 m^(2)/g to 685.90 m^(2)/g,and then decreased to 299.56 m^(2)/g.The total pore volume and micropore volume increased from 0.29 cm^(3)/g and 0.17 cm^(3)/g to 0.30 cm^(3)/g and 0.22 cm^(3)/g,and then decreased to 0.16 cm^(3)/g and 0.10 cm^(3)/g,respectively.The optimized ratio was 1:8.During the activation process,iron ions infiltrated the activated carbon to promote the development of the pore structure,the pore size of which was between 2.5 nm and 3 nm in daimeter.This approach could enhance the capacity for adsorption of ethyl acetate.It is worth noting that the ACs displaying the largest specific surface area and total pore volume(685.90 m^(2)/g and 0.30 cm^(3)/g)were formed under the optimized activation conditions(950℃,20%(volume)of CO_(2),ratio 1:5),and the maximum AC capacity for adsorption of ethyl acetate was 962.62 mg/g.After seven repeated thermal regeneration experiments,the saturated AC adsorption capacity was still above 90%.展开更多
The application of coal-based reduction in the efficient recovery of iron from refractory iron-bearing resources is comprehensively reviewed.Currently,the development and beneficiation of refractory iron-bearing resou...The application of coal-based reduction in the efficient recovery of iron from refractory iron-bearing resources is comprehensively reviewed.Currently,the development and beneficiation of refractory iron-bearing resources have attracted increasing attention.However,the effect of iron recovery by traditional beneficiation methods is unacceptable.Coal-based reduction followed by magnetic separation is proposed,which adopts coal as the reductant to reduce iron oxides to metallic iron below the melting temperature.The metallic iron particles aggregate and grow,and the particle size continuously increases to be suitable for magnetic separation.The optimization and application of coal-based reduction have been abundantly researched.A detailed literature study on coal-based reduction is performed from the perspectives of thermodynamics,reduction kinetics,growth of metallic iron particles,additives,and application.The coal-based reduction industrial equipment can be developed based on the existing pyrometallurgical equipments,rotary hearth furnace and rotary kiln,which are introduced briefly.However,coal-based reduction currently mainly adopts coal as a reductant and fuel,which may result in high levels of carbon dioxide emissions,energy consumption,and pollution.Technological innovation aiming at decreasing carbon dioxide emissions is a new trend of green and sustainable development of the steel industry.Therefore,the substitution of coal with clean energy(hydrogen,biomass,etc.)for iron oxide reduction shows promise in the future.展开更多
Based on the process of coal-based self-reduction and melting separation at high temperature, it was investigated that the effect of process factors on the reduction of iron and nickel oxide, the metal yield and the n...Based on the process of coal-based self-reduction and melting separation at high temperature, it was investigated that the effect of process factors on the reduction of iron and nickel oxide, the metal yield and the nickel content in ferronickel about the laterite nickel ore, was from Philippines and contented low nickel, high iron and aluminum. The results showed that if the C/O mole ratio was not higher than 0.5 and the reduction temperature was kept as 1200°C and then increased up to 1500°C, the metal could not separate from molten slag for the A series of experiments, which were only added CaF<sub>2</sub>. However, when the C/O ratio was added up to 0.6 - 0.8, the metal could separate well from the slag, and the yields of Fe and Ni increased gradually. But the nickel content in the metal declined from 1.79% to 1.34%. When the C/O ratio increased to 1.2, and the temperature of melting products obtained at 1200°C and rose to 1550°C, the separation of metal from slag could not be realized in B group of tests, which were only added hydrated lime. However, when both of CaF<sub>2</sub> and hydrated lime were added, the metal could separate from slag in C group. In order to increase the content of nickel in the metal, it is necessary to restrain the reduction of iron oxide. When the C/O mole ratio is 0.6, the nickel content of metal could be 1.79%, which was higher than the theoretical ratio 1.65% of Ni/(Ni + Fe) of the latcritic nickel ore, but the yield of nickle was only 71.3%.展开更多
The scalable production of high grade activated carbon from abundant coal for supercapacitors application is an efficient way to achieve high value-added utilization of coal sources.However,this technology is challeng...The scalable production of high grade activated carbon from abundant coal for supercapacitors application is an efficient way to achieve high value-added utilization of coal sources.However,this technology is challenging due to lack of comprehensive understanding on the mechanism of activation process and effect of external factors.In this paper,the effect of activating temperature and time on the specific capacitance of coal-based activated carbon prepared by H2O steam activation was studied using the response surface method.Under optimal conditions,coal-based activated carbon exhibits the largest specific capacitance of 194.35 F·g^(−1),thanks to the appropriate pore/surface structure and defect degree.Density functional theory calculations explain in detail the mechanism of contraction of aromatic rings and overflow of H2 and CO during the activation.Meanwhile,oxygen-containing functional groups are introduced,contributing to the pseudocapacitance property of coal-based activated carbon.This mechanism of reactions between aromatic carbon and H2O vapor provides understanding on the role of water during coal processing at the molecular level,offering great potential to regulate product distribution and predict rate of pore generation.This insight would contribute to the advancement of other coal processing technology such as gasification.展开更多
A novel composite photocatalyst for photocatalytic decomposition of water for hydrogen evolution was successfully synthesized by in-situ growth of nitrogen and sulfur co-doped coal-based carbon quantum dots(NSCQDs)nan...A novel composite photocatalyst for photocatalytic decomposition of water for hydrogen evolution was successfully synthesized by in-situ growth of nitrogen and sulfur co-doped coal-based carbon quantum dots(NSCQDs)nanoparticles on the surface of sheet cobalt-based metal-organic framework(Co-MOF)and graphitic carbon nitride(g-C_(3)N_(4),CN).The structure and properties of the obtained catalysts were systematically analyzed.NSCQDs effectively broaden the absorption of Co-MOF and CN in the visible region.The new composite photocatalyst has high hydrogen production activity and the hydrogen production rate reaches 6254μmol/(g·h)at pH=9.At the same time,NSCQDs synergy Co-MOF/CN composites have good stability.After four cycles of hydrogen production,the performance remains relatively stable.The tran sient photocurrent response and Nyquist plot experimental results further demonstrate the improvement of carrier separation efficiency in composite catalysts.The semiconductor type(n-type semico nductor)of the single-phase catalyst was determined by the Mott-Schottky test,and the band structure was analyzed.The conductive and valence bands of CN are-0.99 and 1.72 eV,respectively,and the conduction and valence bands of Co-MOF are-1.85 and 1.33 eV,respectively.Th e mechanism of the photocatalytic reaction can be inferred,that is,Z-type heterojunction is formed between CN an d Co-MOF,and NSCQDs was used as cocatalyst.展开更多
Despite the long tradition of fossil carbon(coal,char,and related carbon-based materials)for fueling mankind,the science of transforming them into chemicals is still demandingly progressing in the current energy scena...Despite the long tradition of fossil carbon(coal,char,and related carbon-based materials)for fueling mankind,the science of transforming them into chemicals is still demandingly progressing in the current energy scenario,especially when considering its responsibilities to the global climate change.Traditionally,there are four routes of preparing chemicals directly from fossil carbon,including hydrogasification,gasification,direct liquefaction,and oxidation,in the macroscope of gas-solid reaction(hydrogasification and gasification)and liquid-solid reaction(direct liquefaction and oxidation).When the study goes to microscale,the gas-solid reaction can be considered as the reaction between the severe condensed radicals and gas,while the liquid-solid reaction is the direct reaction between the radical and the activated-molecule.To have a full overview of the area,this review systematically summarizes the main factors in these processes and shows our own perspectives as follows,(ⅰ)stabilizing the free radicals generated from coal and then directly converting them has the highest efficiency in coal utilization;(ⅱ)the research on the self-catalytic process of coal structure will have a profound impact on the direct preparation of chemicals from fossil carbon.Further discussions are also proposed to guide the future study of the area into a more sustainable direction.展开更多
A technique comprising coal-based direct reduction followed by magnetic separation was presented to recover iron and copper from copper slag flotation tailings.Optimal process parameters,such as reductant and additive...A technique comprising coal-based direct reduction followed by magnetic separation was presented to recover iron and copper from copper slag flotation tailings.Optimal process parameters,such as reductant and additive ratios,reduction temperature,and reduction time,were experimentally determined and found to be as follows:a limestone ratio of 25%,a bitumite ratio of 30%,and reduction roasting at 1473 Kfor 90 min.Under these conditions,copper-bearing iron powders(CIP)with an iron content of 90.11% and copper content of 0.86%,indicating iron and copper recoveries of87.25% and 83.44%respectively,were effectively obtained.Scanning electron microscopy and energy dispersive spectroscopy of the CIP revealed that some tiny copper particles were embedded in metal iron and some copper formed alloy with iron,which was difficult to achieve the separation of these two metals.Thus,the copper went into magnetic products by magnetic separation.Adding copper into the steel can produce weathering steel.Therefore,the CIP can be used as an inexpensive raw material for weathering steel.展开更多
A new process for preparing high-purity iron(HPI)was proposed,and it was investigated by laboratory experiments and pilot tests.The results show that under conditions of a reduced temperature of 1075°C,reduced ti...A new process for preparing high-purity iron(HPI)was proposed,and it was investigated by laboratory experiments and pilot tests.The results show that under conditions of a reduced temperature of 1075°C,reduced time of 5 h,and CaO content of 2.5wt%,a DRI with a metallization rate of 96.5%was obtained through coal-based direct reduction of ultra-high-grade iron concentrate.Then,an HPI with a Fe purity of 99.95%and C,Si,Mn,and P contents as low as 0.0008wt%,0.0006wt%,0.0014wt%,and 0.0015wt%,respectively,was prepared by smelting separation of the DRI using a smelting temperature of 1625°C,smelting time of 45 min,and CaO content of 9.3wt%.The product of the pilot test with a scale of 0.01 Mt/a had a lower impurity content than the Chinese industry standard.An HPI with a Fe purity of 99.98wt%can be produced through the direct reduction?smelting separation of ultra-high-grade iron concentrate at relatively low cost.The proposed process shows a promising prospect for application in the future.展开更多
In order to ascertain the reaction behavior of rare earth minerals in coal-based reduction, X-ray diffraction(XRD), scanning electron microscopy(SEM), and energy dispersive spectroscopy(EDS) analyses were applie...In order to ascertain the reaction behavior of rare earth minerals in coal-based reduction, X-ray diffraction(XRD), scanning electron microscopy(SEM), and energy dispersive spectroscopy(EDS) analyses were applied to investigate the rare earth minerals in Bayan Obo.The occurrence state and regularity of rare earth elements were analyzed under different reduction time. The results reveal that rare earth elements in rare earth minerals exist in RE(CO3)F(bastnaesite) and REPO4(monazite). In this research, at 1,498 K with a C/O molar ratio(i.e., molar ratio of fixed carbon in the coal to reducible oxygen in the ore) of2.5, rare earth minerals primarily decompose into RE2O3at5 min. When the time is extended to 10 min, solid-phase reactions occur among RE2O3, CaO, and SiO2, and the resultant is cerium wollastonite(CaO·2RE2O3·3SiO2). At reaction time 〉20 min, rare earth elements mainly exist in cerium wollastonite(CaO·2RE2O3·3SiO2), and the grain size varies in the range of 10–30 μm. The results show that coal-based reduction is efficient to recover rare earth minerals in reduced materials.展开更多
Coal has been the main energy source in China for a long period.Therefore,the energy industry must improve coal power generation efficiency and achieve near-zero CO_(2) emissions.Integrated gasification fuel cell(IGFC...Coal has been the main energy source in China for a long period.Therefore,the energy industry must improve coal power generation efficiency and achieve near-zero CO_(2) emissions.Integrated gasification fuel cell(IGFC)systems that combine coal gasification and high-temperature fuel cells,such as solid oxide fuel cells or molten carbonate fuel cells(MCFCs),are proving to be promising for efficient and clean power generation,compared with traditional coal-fired power plants.In 2017,with the support of National Key R&D Program of China,a consortium led by the China Energy Group and including 12 institutions was formed to develop the advanced IGFC technology with near-zero CO_(2) emissions.The objectives of this project include understanding the performance of an IGFC power generation system under different operating conditions,designing master system principles for engineering optimization,developing key technologies and intellectual property portfolios,setting up supply chains for key materials and equipment,and operating the first megawatt IGFC demonstration system with near-zero CO_(2) emission,in early 2022.In this paper,the main developments and projections pertaining to the IGFC project are highlighted.展开更多
As the limiting factor for an energy storage technique from lab-scale to industrial-scale,cost means not only the price of raw materials but also the simplicity of processing technics.In this work,the oxygen functiona...As the limiting factor for an energy storage technique from lab-scale to industrial-scale,cost means not only the price of raw materials but also the simplicity of processing technics.In this work,the oxygen functionalized carbon materials were obtained from three representative different metamorphic-grade coals,that is,lignite,bitumite,anthracite.Oxygen functional groups like quinones,carboxylic anhydrides,and lactones are easier to form near defects according to the thermogravimetric-mass spectrometry measurements and density functional theory calculation.Considering the highest amount of defects and C=O contained functional groups,the low metamorphic-grade lignite derived carbon exhibits a reversible capacity of 259.7 mA h g^(-1)after 50 cycles at 0.03 A g^(-1),best among these micron sized coal-based carbons.The surface active sites contribute highly stable and majority of sodium storage capacity evidenced by in situ Raman spectra and cyclic voltammetry curves at different scan rates.The coal-based carbon materials in this work offer options for industrial applications of sodium-ion battery anode materials.展开更多
The filling mining method is important in realizing the green mining of mineral resources.Aiming at the problems of land resource occupation,environmental pollution,and rational utilization of coal-based solid wastes ...The filling mining method is important in realizing the green mining of mineral resources.Aiming at the problems of land resource occupation,environmental pollution,and rational utilization of coal-based solid wastes such as coal gangue,fly ash,and desulfurization gypsum,a new paste filling material was developed with coal gangue,fly ash,and desulfurization gypsum as raw materials.The microstructure of the raw materials was analyzed by XRD and SEM.Combined with the Box-Behnken experimental design,the effect of each component on the fluidity of the filling slurry was analyzed through the response surface analysis.The significance of each component on its bleeding and fluidity was determined,and the optimal ratio of the filling slurry was obtained.Experimental results show that the microcosmic morphology of coal gangue,desulfurization gypsum,and gasification slag presents an irregular block and rough particle surface;the microcosmic morphology of fly ash and bottom slag presents first out spherical or quasi spherical particles.Moreover,obvious sintering traces exist on the surface of the bottom slag.The main crystal mineral of coal gangue and fly ash is SiO_(2),the desulfurization gypsum is composed of Ca(SO_(4))(H_(2)O)and Ca(CO_(3))crystal minerals,the gasification slag is composed of carbon and nitrogen compounds,and the main crystal mineral components in the bottom slag sample are SiO_(2) and Al_(x)Si_(y)O_(z) compounds.The order of significance of each key factor on slurry fluidity is as follows:C(desulfurization gypsum)>D(gasification slag and bottom slag 1:1)>A(coal gangue)>B(fly ash).The order of the significance of each key factor on slurry bleeding is as follows:B(fly ash)>C(desulfurization gypsum)>D(gasification slag and bottom slag 1:1)>A(coal gangue).Considering the material preparation,field application,and other conditions,the mass percentage of each factor content of the new paste filling material is as follows:49.5%coal gangue,8.3%fly ash,4.1%desulfurization gypsum,6.2%gasification slag,and 6.2%bottom slag.展开更多
To deal with problems in synergetic development of coal-based energy engineering,this paper,guided by the philosophy of engineering,proposes the synergetic management philosophy of "factors coordination,systems s...To deal with problems in synergetic development of coal-based energy engineering,this paper,guided by the philosophy of engineering,proposes the synergetic management philosophy of "factors coordination,systems synergy,dynamic optimization and three-dimension planning." The paper also establishes the synergetic management system characterized by systems factor synergy,resource-environment synergy and systems boundary extension and supported by the "two-wheel driven"management innovation and technological innovation.In addition,the paper presents a multi-objective dynamic optimization model for energy engineering,designed based on Shenhua's own engineering practice,to analyze Pareto optimal solution in three scenarios:best resource allocation,minimal environmental impact and maximal value creation.This provides important reference to synergetic development strategies and decision-making in engineering management.展开更多
Graphite formed in response to thermal contact metamorphism of coal bodies with magmatic intrusion is referred to as coal-based graphite. The first-order Raman spectrum of all the coal-based graphite taken from the Lu...Graphite formed in response to thermal contact metamorphism of coal bodies with magmatic intrusion is referred to as coal-based graphite. The first-order Raman spectrum of all the coal-based graphite taken from the Lutang area, Hunan Province exhibits a single Raman band near 1585cm-1, which comes directly from in-plane vibration of aromatic layer assigned to the E2g mode. Their Raman band of the structural defect in-plane can be divided into 2 types: one is the defect band (D peak) caused by the primary structural delect of the graphite in graphitization process, which is called D2-peak located at 1 360 cm-1; the other is the defect bank caused by the secondary structural defect in the graphite subject to tectonic shearing stress, which is called D1 peak located at 1370cm-1. The second Raman spectrum of the coal-based graphite shows three-dimensional lattice degree in the coal-based graphite. If the three-dimensional lattice of graphite is not well developed, it exhibits only a band of 2700cm-1; if展开更多
Preparation of activated carbons by a physical activation technique is performed using the methods of coal pyrolysis and gasification at different temperatures. As increasing pyrolysis temperature from 520°C ...Preparation of activated carbons by a physical activation technique is performed using the methods of coal pyrolysis and gasification at different temperatures. As increasing pyrolysis temperature from 520°C to 700°C, the yield of activated carbons from the Khuut (KH) sub-bituminous coal is lowered, and amount of micropores increases gradually;however there is no development of mesopores by the KH coal pyrolysis. When the KH coal has a small loss during its physical activation due to difficulty and inactivity of its macrostructure decomposition, the smaller porosity is developed in the resulting carbons. The Aduunchuluun (AD) lignite is activated by pyrolysis and gasification at the highest temperature of 700°C in the present study. It is identified that the gasification of AD lignite develops well a porous structure with the highest surface area of 522 m2/g which is three times larger than that (155 m2/g) of the activated carbon produced by pyrolysis of the same lignite. The IR and SEM analysis confirm a significant difference in chemical and structural changes between the AD, KH raw coals and corresponding carbon samples in the physical activation processes.展开更多
Over the past 80 years,dozens of underground coal gasification(UCG)mine field tests have been carried out around the world.However,in the early days,only a small number of shallow UCG projects in the former Soviet Uni...Over the past 80 years,dozens of underground coal gasification(UCG)mine field tests have been carried out around the world.However,in the early days,only a small number of shallow UCG projects in the former Soviet Union achieved commercialised production.In this century,a few pilot projects in Australia also achieved short-term small-scale commercialised production using modern UCG technology.However,the commercialisation of UCG,especially medium-deep UCG projects with good development prospects but difficult underground engineering conditions,has not progressed smoothly around the world.Considering investment economy,a single gasifier must realise a high daily output and accumulated output,as well as hold a long gasification tunnel to control a large number of coal resources.However,a long gasification tunnel can easily be affected by blockages and failure,for which the remedial solutions are difficult and expensive,which greatly restricts the investment economy.The design of the underground gasifier determines the success or failure of UCG projects,and it also requires the related petroleum engineering technology.Combining the advantages of the linear horizontal well(L-CRIP)and parallel horizontal well(P-CRIP),this paper proposes a new design scheme for an“inclined ladder”underground gasifier.That is to say,the combination of the main shaft of paired P-CRIP and multiple branch horizontal well gasification tunnels is adopted to realise the control of a large number of coal resources in a single gasifier.The completion of the main shaft by well cementation is beneficial for maintaining the integrity of the main shaft and the stability of the main structure.The branch horizontal well is used as the gasification tunnel,but the length and number of retracting injection points are limited,effectively reducing the probability of blockage or failure.The branch horizontal well spacing can be adjusted flexibly to avoid minor faults and large cracks,which is conducive to increasing the resource utilisation rate.In addition,for multi-layer thin coal seams or ultra-thick coal seams,a multi-layer gasifier sharing vertical well sections can be deployed,thereby saving investment on the vertical well sections.Through preliminary analysis,this gasifier design scheme can be realised in engineering,making it suitable for largescale deployment where it can increase the resource utilisation rate and ensure stable and controllable operations.The new gasifier has outstanding advantages in investment economy,and good prospects for application in the commercial UCG projects of medium-deep coal seams.展开更多
Hydrogen is considered a secondary source of energy,commonly referred to as an energy carrier.It has the highest energy content when compared to other common fuels by weight,having great potential for further developm...Hydrogen is considered a secondary source of energy,commonly referred to as an energy carrier.It has the highest energy content when compared to other common fuels by weight,having great potential for further development.Hydrogen can be produced from various domestic resources but,based on the fossil resource conditions in China,coal-based hydrogen energy is considered to be the most valuable,because it is not only an effective way to develop clean energy,but also a proactive exploration of the clean usage of traditional coal resources.In this article,the sorption-enhanced water-gas shift technology in the coal-to-hydrogen section and the hydrogen-storage and transport technology with liquid aromatics are introduced and basic mechanisms,technical advantages,latest progress and future R&D focuses of hydrogen-production and storage processes are listed and discussed.As a conclusion,after considering the development frame and the business characteristics of CHN Energy Group,a conceptual architecture for developing coal-based hydrogen energy and the corresponding supply chain,is proposed.展开更多
基金This work was financially supported by the National Key R&D Program of China(Nos.2020YFC1806504 and 2019YFC1904903)the Yue Qi Young Scholar Project,China University of Mining&Technology(Beijing)(No.2017QN12).
文摘Zeolite derived from coal-based solid wastes(coal gangue and coal fly ash)can overcome the environmental problems caused by coal-based solid wastes and achieve valuable utilization.In this paper,the physicochemical properties of coal gangue and coal fly ash are introduced.The mechanism and application characteristics of the pretreatment processes for zeolite synthesis from coal-based solid wastes are also introduced.The synthesis processes of coal-based solid waste zeolite and their advantages and disadvantages are summarized.Furthermore,the application characteristics of various coal-based solid waste zeolites and their common application fields are illustrated.Finally,we propose an alkaline fusion-assisted supercritical hydrothermal crystallization as an efficient method for synthesizing coal-based solid waste zeolites.In addition,more attention should be given to the recycling of alkaline waste liquid and the application of coal-based solid waste zeolites in the field of volatile organic compound adsorption removal.
基金financially supported by the National Natural Science Foundation of China (No.51604063)
文摘To understand the migration mechanisms of phosphorus(P)during coal-based reduction,a high-phosphorus oolitic iron ore was reduced by coal under various experimental conditions.The migration characteristics and kinetics of P were investigated by a field-emission electron probe microanalyzer(FE-EPMA)and using the basic principle of solid phase mass transfer,respectively.Experimental results showed that the P transferred from the slag to the metallic phase during reduction,and the migration process could be divided into three stages:phosphorus diffusing from the slag to the metallic interface,the formation of Fe P compounds at the slag metal interface and P diffusing from the slag metal interface to the metallic interior.The reduction time and temperature significantly influenced the phosphorus content of the metallic and slag phases.The P content of the metallic phase increased with increasing reduction time and temperature,while that of the slag phase gradually decreased.The P diffusion constant and activation energy were determined and a migration kinetics model of P in coal-based reduction was proposed.P diffusion in the metallic phase was the controlling step of the P migration.
文摘NaY zeolites were in-situ synthesized from coal-based kaolin via thehydrothermal method. The effects of various factors on the structure of the samples were extensivelyinvestigated. The samples were characterized by N_2 adsorption, XRD, IR and DTG-DTA methods, andthe results show that the crystallization temperature and amount of added water play an importantrole in the formation of the zeolite structure. The 4A and P zeolites are the competitive phasepresent in the resulting product. However, NaY zeolites with a higher relative crystallinity,excluding impure crystals and the well hydrothermal stability, can be synthesized from coal-basedkaolin. These zeolites possess a larger surface area and a narrow pore size distribution, and thismeans that optimization of this process might result in a commercial route to synthesize NaYzeolites from coal-based kaolin.
基金The authors thank the National Natural Science Foundation of China(No.51906130)the Natural Science Foundation of Shandong Province(No.ZR2019BEE053)+1 种基金the Key R&D and Development Plan of Shandong Province(2020CXGC011401)the Foundation of Shandong Key Lab of Energy Carbon Reduction and Resource Utilization,Shandong University(No.ECRRU201804)for the financial support.
文摘In this study,the Heishan coal was used to prepare a series of activated carbon(AC)samples via a vapor deposition method.The effects of the Fe(NO_(3))3/coal weight ratio on the physicochemical properties of the activated carbon were systematically investigated,and the AC samples were analyzed by the N2 adsorption-desorption technique,the scanning electron microscopy,the X-ray diffraction,the Raman spectroscopy,and the Fourier transform infrared spectroscopy.Furthermore,the adsorption properties of ethyl acetate were investigated.The results indicated that as the Fe(NO_(3))3/coal mass ratio increased from 1:8 to 1:2,the specific surface area,the total pore volume and the micropore volume initially increased and then decreased.The specific surface area increased from 560.86 m^(2)/g to 685.90 m^(2)/g,and then decreased to 299.56 m^(2)/g.The total pore volume and micropore volume increased from 0.29 cm^(3)/g and 0.17 cm^(3)/g to 0.30 cm^(3)/g and 0.22 cm^(3)/g,and then decreased to 0.16 cm^(3)/g and 0.10 cm^(3)/g,respectively.The optimized ratio was 1:8.During the activation process,iron ions infiltrated the activated carbon to promote the development of the pore structure,the pore size of which was between 2.5 nm and 3 nm in daimeter.This approach could enhance the capacity for adsorption of ethyl acetate.It is worth noting that the ACs displaying the largest specific surface area and total pore volume(685.90 m^(2)/g and 0.30 cm^(3)/g)were formed under the optimized activation conditions(950℃,20%(volume)of CO_(2),ratio 1:5),and the maximum AC capacity for adsorption of ethyl acetate was 962.62 mg/g.After seven repeated thermal regeneration experiments,the saturated AC adsorption capacity was still above 90%.
基金financially supported by the National Natural Science Foundation of China (No. 52022019)the National Key R&D Program of China (No. 2021YFC2901000)the Fok Ying Tung Education Foundation (No. 161045)
文摘The application of coal-based reduction in the efficient recovery of iron from refractory iron-bearing resources is comprehensively reviewed.Currently,the development and beneficiation of refractory iron-bearing resources have attracted increasing attention.However,the effect of iron recovery by traditional beneficiation methods is unacceptable.Coal-based reduction followed by magnetic separation is proposed,which adopts coal as the reductant to reduce iron oxides to metallic iron below the melting temperature.The metallic iron particles aggregate and grow,and the particle size continuously increases to be suitable for magnetic separation.The optimization and application of coal-based reduction have been abundantly researched.A detailed literature study on coal-based reduction is performed from the perspectives of thermodynamics,reduction kinetics,growth of metallic iron particles,additives,and application.The coal-based reduction industrial equipment can be developed based on the existing pyrometallurgical equipments,rotary hearth furnace and rotary kiln,which are introduced briefly.However,coal-based reduction currently mainly adopts coal as a reductant and fuel,which may result in high levels of carbon dioxide emissions,energy consumption,and pollution.Technological innovation aiming at decreasing carbon dioxide emissions is a new trend of green and sustainable development of the steel industry.Therefore,the substitution of coal with clean energy(hydrogen,biomass,etc.)for iron oxide reduction shows promise in the future.
文摘Based on the process of coal-based self-reduction and melting separation at high temperature, it was investigated that the effect of process factors on the reduction of iron and nickel oxide, the metal yield and the nickel content in ferronickel about the laterite nickel ore, was from Philippines and contented low nickel, high iron and aluminum. The results showed that if the C/O mole ratio was not higher than 0.5 and the reduction temperature was kept as 1200°C and then increased up to 1500°C, the metal could not separate from molten slag for the A series of experiments, which were only added CaF<sub>2</sub>. However, when the C/O ratio was added up to 0.6 - 0.8, the metal could separate well from the slag, and the yields of Fe and Ni increased gradually. But the nickel content in the metal declined from 1.79% to 1.34%. When the C/O ratio increased to 1.2, and the temperature of melting products obtained at 1200°C and rose to 1550°C, the separation of metal from slag could not be realized in B group of tests, which were only added hydrated lime. However, when both of CaF<sub>2</sub> and hydrated lime were added, the metal could separate from slag in C group. In order to increase the content of nickel in the metal, it is necessary to restrain the reduction of iron oxide. When the C/O mole ratio is 0.6, the nickel content of metal could be 1.79%, which was higher than the theoretical ratio 1.65% of Ni/(Ni + Fe) of the latcritic nickel ore, but the yield of nickle was only 71.3%.
基金support by Shaanxi Province Technological Innovation Guidance Special (Grant No.2021QFY04-01)technical support by Analytical Instrumentation Center of XUST.
文摘The scalable production of high grade activated carbon from abundant coal for supercapacitors application is an efficient way to achieve high value-added utilization of coal sources.However,this technology is challenging due to lack of comprehensive understanding on the mechanism of activation process and effect of external factors.In this paper,the effect of activating temperature and time on the specific capacitance of coal-based activated carbon prepared by H2O steam activation was studied using the response surface method.Under optimal conditions,coal-based activated carbon exhibits the largest specific capacitance of 194.35 F·g^(−1),thanks to the appropriate pore/surface structure and defect degree.Density functional theory calculations explain in detail the mechanism of contraction of aromatic rings and overflow of H2 and CO during the activation.Meanwhile,oxygen-containing functional groups are introduced,contributing to the pseudocapacitance property of coal-based activated carbon.This mechanism of reactions between aromatic carbon and H2O vapor provides understanding on the role of water during coal processing at the molecular level,offering great potential to regulate product distribution and predict rate of pore generation.This insight would contribute to the advancement of other coal processing technology such as gasification.
基金Project supported by the Ningxia Natural Science Foundation of China(2023AAC03285)National Natural Science Foundation of China(21666001)+1 种基金Innovative Team for Transforming Waste Cooking Oil into Clean Energy and High Value-added Chemicals,ChinaNingxia Low-grade Resource High Value Utilization and Environmental Chemical Integration Technology Innovation Team Project,China。
文摘A novel composite photocatalyst for photocatalytic decomposition of water for hydrogen evolution was successfully synthesized by in-situ growth of nitrogen and sulfur co-doped coal-based carbon quantum dots(NSCQDs)nanoparticles on the surface of sheet cobalt-based metal-organic framework(Co-MOF)and graphitic carbon nitride(g-C_(3)N_(4),CN).The structure and properties of the obtained catalysts were systematically analyzed.NSCQDs effectively broaden the absorption of Co-MOF and CN in the visible region.The new composite photocatalyst has high hydrogen production activity and the hydrogen production rate reaches 6254μmol/(g·h)at pH=9.At the same time,NSCQDs synergy Co-MOF/CN composites have good stability.After four cycles of hydrogen production,the performance remains relatively stable.The tran sient photocurrent response and Nyquist plot experimental results further demonstrate the improvement of carrier separation efficiency in composite catalysts.The semiconductor type(n-type semico nductor)of the single-phase catalyst was determined by the Mott-Schottky test,and the band structure was analyzed.The conductive and valence bands of CN are-0.99 and 1.72 eV,respectively,and the conduction and valence bands of Co-MOF are-1.85 and 1.33 eV,respectively.Th e mechanism of the photocatalytic reaction can be inferred,that is,Z-type heterojunction is formed between CN an d Co-MOF,and NSCQDs was used as cocatalyst.
基金supported by National Natural Science Foundation of China(52161145403 and 22072164)the Joint Fund of the Yulin University and the Dalian National Laboratory for Clean Energy(Grant.YLU-DNL Fund 2022002)。
文摘Despite the long tradition of fossil carbon(coal,char,and related carbon-based materials)for fueling mankind,the science of transforming them into chemicals is still demandingly progressing in the current energy scenario,especially when considering its responsibilities to the global climate change.Traditionally,there are four routes of preparing chemicals directly from fossil carbon,including hydrogasification,gasification,direct liquefaction,and oxidation,in the macroscope of gas-solid reaction(hydrogasification and gasification)and liquid-solid reaction(direct liquefaction and oxidation).When the study goes to microscale,the gas-solid reaction can be considered as the reaction between the severe condensed radicals and gas,while the liquid-solid reaction is the direct reaction between the radical and the activated-molecule.To have a full overview of the area,this review systematically summarizes the main factors in these processes and shows our own perspectives as follows,(ⅰ)stabilizing the free radicals generated from coal and then directly converting them has the highest efficiency in coal utilization;(ⅱ)the research on the self-catalytic process of coal structure will have a profound impact on the direct preparation of chemicals from fossil carbon.Further discussions are also proposed to guide the future study of the area into a more sustainable direction.
基金the Natural Science Foundation of China(No.51304012)the State Key Laboratory of High-Efficient Mining and Safety of Metal Mines for the financial support for this research
文摘A technique comprising coal-based direct reduction followed by magnetic separation was presented to recover iron and copper from copper slag flotation tailings.Optimal process parameters,such as reductant and additive ratios,reduction temperature,and reduction time,were experimentally determined and found to be as follows:a limestone ratio of 25%,a bitumite ratio of 30%,and reduction roasting at 1473 Kfor 90 min.Under these conditions,copper-bearing iron powders(CIP)with an iron content of 90.11% and copper content of 0.86%,indicating iron and copper recoveries of87.25% and 83.44%respectively,were effectively obtained.Scanning electron microscopy and energy dispersive spectroscopy of the CIP revealed that some tiny copper particles were embedded in metal iron and some copper formed alloy with iron,which was difficult to achieve the separation of these two metals.Thus,the copper went into magnetic products by magnetic separation.Adding copper into the steel can produce weathering steel.Therefore,the CIP can be used as an inexpensive raw material for weathering steel.
基金the National Natural Science Foundation of China(No.51904063)the Fundamental Research Funds for the Central Universities,China(Nos.N172503016,N172502005,and N172506011)the China Postdoctoral Science Foundation(No.2018M640259).
文摘A new process for preparing high-purity iron(HPI)was proposed,and it was investigated by laboratory experiments and pilot tests.The results show that under conditions of a reduced temperature of 1075°C,reduced time of 5 h,and CaO content of 2.5wt%,a DRI with a metallization rate of 96.5%was obtained through coal-based direct reduction of ultra-high-grade iron concentrate.Then,an HPI with a Fe purity of 99.95%and C,Si,Mn,and P contents as low as 0.0008wt%,0.0006wt%,0.0014wt%,and 0.0015wt%,respectively,was prepared by smelting separation of the DRI using a smelting temperature of 1625°C,smelting time of 45 min,and CaO content of 9.3wt%.The product of the pilot test with a scale of 0.01 Mt/a had a lower impurity content than the Chinese industry standard.An HPI with a Fe purity of 99.98wt%can be produced through the direct reduction?smelting separation of ultra-high-grade iron concentrate at relatively low cost.The proposed process shows a promising prospect for application in the future.
基金financially supported by the National Natural Science Foundation of China (Nos. 51204033 and 51134002)
文摘In order to ascertain the reaction behavior of rare earth minerals in coal-based reduction, X-ray diffraction(XRD), scanning electron microscopy(SEM), and energy dispersive spectroscopy(EDS) analyses were applied to investigate the rare earth minerals in Bayan Obo.The occurrence state and regularity of rare earth elements were analyzed under different reduction time. The results reveal that rare earth elements in rare earth minerals exist in RE(CO3)F(bastnaesite) and REPO4(monazite). In this research, at 1,498 K with a C/O molar ratio(i.e., molar ratio of fixed carbon in the coal to reducible oxygen in the ore) of2.5, rare earth minerals primarily decompose into RE2O3at5 min. When the time is extended to 10 min, solid-phase reactions occur among RE2O3, CaO, and SiO2, and the resultant is cerium wollastonite(CaO·2RE2O3·3SiO2). At reaction time 〉20 min, rare earth elements mainly exist in cerium wollastonite(CaO·2RE2O3·3SiO2), and the grain size varies in the range of 10–30 μm. The results show that coal-based reduction is efficient to recover rare earth minerals in reduced materials.
基金This work was financially supported by the National Key R&D Program of China(2017YFB0601900).
文摘Coal has been the main energy source in China for a long period.Therefore,the energy industry must improve coal power generation efficiency and achieve near-zero CO_(2) emissions.Integrated gasification fuel cell(IGFC)systems that combine coal gasification and high-temperature fuel cells,such as solid oxide fuel cells or molten carbonate fuel cells(MCFCs),are proving to be promising for efficient and clean power generation,compared with traditional coal-fired power plants.In 2017,with the support of National Key R&D Program of China,a consortium led by the China Energy Group and including 12 institutions was formed to develop the advanced IGFC technology with near-zero CO_(2) emissions.The objectives of this project include understanding the performance of an IGFC power generation system under different operating conditions,designing master system principles for engineering optimization,developing key technologies and intellectual property portfolios,setting up supply chains for key materials and equipment,and operating the first megawatt IGFC demonstration system with near-zero CO_(2) emission,in early 2022.In this paper,the main developments and projections pertaining to the IGFC project are highlighted.
基金financially supported the National Natural Science Foundation of China(No.21878207)Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi Province(2019)Key Research and Development Project(International Science and Technology Cooperation Program)(No.201803D421011)。
文摘As the limiting factor for an energy storage technique from lab-scale to industrial-scale,cost means not only the price of raw materials but also the simplicity of processing technics.In this work,the oxygen functionalized carbon materials were obtained from three representative different metamorphic-grade coals,that is,lignite,bitumite,anthracite.Oxygen functional groups like quinones,carboxylic anhydrides,and lactones are easier to form near defects according to the thermogravimetric-mass spectrometry measurements and density functional theory calculation.Considering the highest amount of defects and C=O contained functional groups,the low metamorphic-grade lignite derived carbon exhibits a reversible capacity of 259.7 mA h g^(-1)after 50 cycles at 0.03 A g^(-1),best among these micron sized coal-based carbons.The surface active sites contribute highly stable and majority of sodium storage capacity evidenced by in situ Raman spectra and cyclic voltammetry curves at different scan rates.The coal-based carbon materials in this work offer options for industrial applications of sodium-ion battery anode materials.
基金We acknowledge the financial support for this work provided by the National Natural Science Foundation of China(Grant No.51774010)National Key R&D Program of China(Grant No.2019YF1904304).
文摘The filling mining method is important in realizing the green mining of mineral resources.Aiming at the problems of land resource occupation,environmental pollution,and rational utilization of coal-based solid wastes such as coal gangue,fly ash,and desulfurization gypsum,a new paste filling material was developed with coal gangue,fly ash,and desulfurization gypsum as raw materials.The microstructure of the raw materials was analyzed by XRD and SEM.Combined with the Box-Behnken experimental design,the effect of each component on the fluidity of the filling slurry was analyzed through the response surface analysis.The significance of each component on its bleeding and fluidity was determined,and the optimal ratio of the filling slurry was obtained.Experimental results show that the microcosmic morphology of coal gangue,desulfurization gypsum,and gasification slag presents an irregular block and rough particle surface;the microcosmic morphology of fly ash and bottom slag presents first out spherical or quasi spherical particles.Moreover,obvious sintering traces exist on the surface of the bottom slag.The main crystal mineral of coal gangue and fly ash is SiO_(2),the desulfurization gypsum is composed of Ca(SO_(4))(H_(2)O)and Ca(CO_(3))crystal minerals,the gasification slag is composed of carbon and nitrogen compounds,and the main crystal mineral components in the bottom slag sample are SiO_(2) and Al_(x)Si_(y)O_(z) compounds.The order of significance of each key factor on slurry fluidity is as follows:C(desulfurization gypsum)>D(gasification slag and bottom slag 1:1)>A(coal gangue)>B(fly ash).The order of the significance of each key factor on slurry bleeding is as follows:B(fly ash)>C(desulfurization gypsum)>D(gasification slag and bottom slag 1:1)>A(coal gangue).Considering the material preparation,field application,and other conditions,the mass percentage of each factor content of the new paste filling material is as follows:49.5%coal gangue,8.3%fly ash,4.1%desulfurization gypsum,6.2%gasification slag,and 6.2%bottom slag.
文摘To deal with problems in synergetic development of coal-based energy engineering,this paper,guided by the philosophy of engineering,proposes the synergetic management philosophy of "factors coordination,systems synergy,dynamic optimization and three-dimension planning." The paper also establishes the synergetic management system characterized by systems factor synergy,resource-environment synergy and systems boundary extension and supported by the "two-wheel driven"management innovation and technological innovation.In addition,the paper presents a multi-objective dynamic optimization model for energy engineering,designed based on Shenhua's own engineering practice,to analyze Pareto optimal solution in three scenarios:best resource allocation,minimal environmental impact and maximal value creation.This provides important reference to synergetic development strategies and decision-making in engineering management.
基金Project supported by the National Natural Science Foundation of China.
文摘Graphite formed in response to thermal contact metamorphism of coal bodies with magmatic intrusion is referred to as coal-based graphite. The first-order Raman spectrum of all the coal-based graphite taken from the Lutang area, Hunan Province exhibits a single Raman band near 1585cm-1, which comes directly from in-plane vibration of aromatic layer assigned to the E2g mode. Their Raman band of the structural defect in-plane can be divided into 2 types: one is the defect band (D peak) caused by the primary structural delect of the graphite in graphitization process, which is called D2-peak located at 1 360 cm-1; the other is the defect bank caused by the secondary structural defect in the graphite subject to tectonic shearing stress, which is called D1 peak located at 1370cm-1. The second Raman spectrum of the coal-based graphite shows three-dimensional lattice degree in the coal-based graphite. If the three-dimensional lattice of graphite is not well developed, it exhibits only a band of 2700cm-1; if
文摘Preparation of activated carbons by a physical activation technique is performed using the methods of coal pyrolysis and gasification at different temperatures. As increasing pyrolysis temperature from 520°C to 700°C, the yield of activated carbons from the Khuut (KH) sub-bituminous coal is lowered, and amount of micropores increases gradually;however there is no development of mesopores by the KH coal pyrolysis. When the KH coal has a small loss during its physical activation due to difficulty and inactivity of its macrostructure decomposition, the smaller porosity is developed in the resulting carbons. The Aduunchuluun (AD) lignite is activated by pyrolysis and gasification at the highest temperature of 700°C in the present study. It is identified that the gasification of AD lignite develops well a porous structure with the highest surface area of 522 m2/g which is three times larger than that (155 m2/g) of the activated carbon produced by pyrolysis of the same lignite. The IR and SEM analysis confirm a significant difference in chemical and structural changes between the AD, KH raw coals and corresponding carbon samples in the physical activation processes.
文摘Over the past 80 years,dozens of underground coal gasification(UCG)mine field tests have been carried out around the world.However,in the early days,only a small number of shallow UCG projects in the former Soviet Union achieved commercialised production.In this century,a few pilot projects in Australia also achieved short-term small-scale commercialised production using modern UCG technology.However,the commercialisation of UCG,especially medium-deep UCG projects with good development prospects but difficult underground engineering conditions,has not progressed smoothly around the world.Considering investment economy,a single gasifier must realise a high daily output and accumulated output,as well as hold a long gasification tunnel to control a large number of coal resources.However,a long gasification tunnel can easily be affected by blockages and failure,for which the remedial solutions are difficult and expensive,which greatly restricts the investment economy.The design of the underground gasifier determines the success or failure of UCG projects,and it also requires the related petroleum engineering technology.Combining the advantages of the linear horizontal well(L-CRIP)and parallel horizontal well(P-CRIP),this paper proposes a new design scheme for an“inclined ladder”underground gasifier.That is to say,the combination of the main shaft of paired P-CRIP and multiple branch horizontal well gasification tunnels is adopted to realise the control of a large number of coal resources in a single gasifier.The completion of the main shaft by well cementation is beneficial for maintaining the integrity of the main shaft and the stability of the main structure.The branch horizontal well is used as the gasification tunnel,but the length and number of retracting injection points are limited,effectively reducing the probability of blockage or failure.The branch horizontal well spacing can be adjusted flexibly to avoid minor faults and large cracks,which is conducive to increasing the resource utilisation rate.In addition,for multi-layer thin coal seams or ultra-thick coal seams,a multi-layer gasifier sharing vertical well sections can be deployed,thereby saving investment on the vertical well sections.Through preliminary analysis,this gasifier design scheme can be realised in engineering,making it suitable for largescale deployment where it can increase the resource utilisation rate and ensure stable and controllable operations.The new gasifier has outstanding advantages in investment economy,and good prospects for application in the commercial UCG projects of medium-deep coal seams.
文摘Hydrogen is considered a secondary source of energy,commonly referred to as an energy carrier.It has the highest energy content when compared to other common fuels by weight,having great potential for further development.Hydrogen can be produced from various domestic resources but,based on the fossil resource conditions in China,coal-based hydrogen energy is considered to be the most valuable,because it is not only an effective way to develop clean energy,but also a proactive exploration of the clean usage of traditional coal resources.In this article,the sorption-enhanced water-gas shift technology in the coal-to-hydrogen section and the hydrogen-storage and transport technology with liquid aromatics are introduced and basic mechanisms,technical advantages,latest progress and future R&D focuses of hydrogen-production and storage processes are listed and discussed.As a conclusion,after considering the development frame and the business characteristics of CHN Energy Group,a conceptual architecture for developing coal-based hydrogen energy and the corresponding supply chain,is proposed.