Gasification is a highly effective technology for converting biomass into fuel gas or syngas.While various gas-ifiers have been commercialized for fuel gas production,mitigating tar formation in gasifiers remains chal...Gasification is a highly effective technology for converting biomass into fuel gas or syngas.While various gas-ifiers have been commercialized for fuel gas production,mitigating tar formation in gasifiers remains chal-lenging.This review is devoted to summarizing the general strategies adopted in various gasifiers to reduce tar formation for high-efficiency clean gasification.For single-bed and staged-gasification processes,their low-tar strategies are typically different.In the single-bed processes,the low-tar strategies involve in-bed intensifica-tion achieved by controlling flow directions of gas and particles inside the gasifier.During the gasification,these two components often have different temperatures to facilitate thermochemical interactions between them.Meanwhile,the two-stage gasifiers are generally designed to decouple pyrolysis,gasification and tar cracking reactions for maximizing the benefits(such as yield and efficiency)realized from the interactions among these reactions.In addition to minimizing tar formation,the approach of reaction decoupling can also raise the calorific value of product gas,even without use of oxygen,and/or improve the adaptability of gasification technology to the feedstocks with various moisture contents and particle sizes.The reanalysis based on those essential low-tar strategies is expected to gain alternative insights into the reaction principles implicated in most advanced biomass gasification technologies.展开更多
As a renewable energy source,the thermal conversion of poultry manure,is a promising waste treatment solution that can generate circular economic outputs such as energy and reduce greenhouse gas emissions.Currently,pr...As a renewable energy source,the thermal conversion of poultry manure,is a promising waste treatment solution that can generate circular economic outputs such as energy and reduce greenhouse gas emissions.Currently,pressurized gasification of poultry manure is still a novel research field,especially when combined with a novel technological route of oxy-fuel gasification.Oxy-fuel gasification is a newly proposed and promising gasification technology for power generation that facilitates future carbon capture and storage.In this work,based on a commercially operated industrial-scale chicken manure gasification power plant in Singapore,we presented an interesting first exploration of the coupled pressurization technology for oxy-fuel gasification of poultry manure using CFD numerical simulation,analyzed the effects of pressure and oxygen enrichment concentration as well as the coupling mechanism between them,and discussed the conversion and emission of nitrogen-and sulfur-containing pollutants.The results indicate that under oxy-fuel gasification condition(Oxy-30,i.e.,30%O_(2)/70%CO_(2)),as the pressure increases from 0.1 to 0.5 MPa,the CO concentration in the syngas increases slightly,the H_(2)concentration increases to approximately 25%,and the CH4 concentration(less than 1%)decreases,resulting in an increase in the calorific value of syngas from 5.2 to 5.6 MJ·m^(-3).Compared to atmospheric pressure conditions,a relatively higher oxygen-enriched concentration interval(Oxy-40 to Oxy-50)under pressurized conditions is advantageous for autothermal gasification.Pressurization increases NO precursors production and also promotes homogeneous and heterogeneous reduction of NO,and provides favorable conditions for self-desulfurization.This work offers reference for the realization of a highly efficient and low-energy-consumption thermochemical treatment of livestock manure coupled with negative carbon emission technology.展开更多
The utilization of iron coke provides a green pathway for low-carbon ironmaking.To uncover the influence mechanism of iron ore on the behavior and kinetics of iron coke gasification,the effect of iron ore on the micro...The utilization of iron coke provides a green pathway for low-carbon ironmaking.To uncover the influence mechanism of iron ore on the behavior and kinetics of iron coke gasification,the effect of iron ore on the microstructure of iron coke was investigated.Furthermore,a comparative study of the gasification reactions between iron coke and coke was conducted through non-isothermal thermogravimetric method.The findings indicate that compared to coke,iron coke exhibits an augmentation in micropores and specific surface area,and the micropores further extend and interconnect.This provides more adsorption sites for CO_(2) molecules during the gasification process,resulting in a reduction in the initial gasification temperature of iron coke.Accelerating the heating rate in non-isothermal gasification can enhance the reactivity of iron coke.The metallic iron reduced from iron ore is embedded in the carbon matrix,reducing the orderliness of the carbon structure,which is primarily responsible for the heightened reactivity of the carbon atoms.The kinetic study indicates that the random pore model can effectively represent the gasification process of iron coke due to its rich pore structure.Moreover,as the proportion of iron ore increases,the activation energy for the carbon gasification gradually decreases,from 246.2 kJ/mol for coke to 192.5 kJ/mol for iron coke 15wt%.展开更多
Molten salt gasification is a promising technology for biomass conversion due to its advantages of superior heat transfer and the ability of utilizing solar energy to reduce carbon emission.In this study,the character...Molten salt gasification is a promising technology for biomass conversion due to its advantages of superior heat transfer and the ability of utilizing solar energy to reduce carbon emission.In this study,the characteristics of corncob CO_(2)-gasification in molten salt environments is thoroughly investigated,and the approach of introducing Fe_(2)O_(3) as catalyst to enhance the syngas yield is proposed.The results showed that the molten salts significantly promoted the conversion of corncob into gaseous products with very low tar and char yield.Compared to O_(2) and H_(2)O atmospheres,utilizing CO_(2) as gasifying agent enhanced the yield of gaseous products during the corncob gasification,especially the yields of CO and H_(2).The introduction of Fe_(2)O_(3) as a catalyst could further increase the yield of gaseous products and the cold gas efficiency(CGE),and the yield of syngas was increased into 2258.3 ml·g^(−1) with a high CGE of 105.8%in 900℃.The findings evidenced that CO_(2) gasification in the molten salt environment with Fe_(2)O_(3) addition can promote the cracking of tar,increasing the syngas yield significantly.Moreover,the energy required to drive the gasification process was calculated,and the total energy consumption was calculated as 16.83 GJ·t^(−1).The study opened up a new solution for the biomass gasification,exhibiting a great potential in distributed energy or chemical systems.展开更多
Temperature is a critical factor influencing the performance of coal catalytic hydrogasification in bubbling fluidized bed gasifiers.Numerical simulations at various temperatures(1023 K,1073 K,1123 K,and 1173 K)are co...Temperature is a critical factor influencing the performance of coal catalytic hydrogasification in bubbling fluidized bed gasifiers.Numerical simulations at various temperatures(1023 K,1073 K,1123 K,and 1173 K)are conducted to elucidate the mechanisms by which temperature affects bubble size,global reaction performance,and particle-scale reactivity.The simulation results indicate that bubble size increases at elevated temperatures,while H_(2)-char hydrogasification reactivity is enhanced.Particle trajectory analyses reveal that particles sized between 100 and 250μm undergo intense char hydrogasification in the dense phase,contributing to the formation of hot spots.To assess the impact of temperature on the particle-scale flow-transfer-reaction process,the dimensionless quantities of Reynolds,Nusselt,and Sherwood numbers,along with the solids dispersion coefficient,are calculated.It is found that higher temperatures inhibit bubble-induced mass and heat transfer.In general,3 MPa,1123 K,and 3-4 fluidization numbers are identified as the optimal conditions for particles ranging from 0 to350μm.These findings provide valuable insights into the inherent interactions between temperature and gas-particle reaction.展开更多
A new adsorbent was successfully prepared by hydrothermal treatment and chemical activation through coal gasification fine slag(CGFS)and blue algae(BA)as raw materials and used for CO_(2)capture.The CO_(2)chemisorptio...A new adsorbent was successfully prepared by hydrothermal treatment and chemical activation through coal gasification fine slag(CGFS)and blue algae(BA)as raw materials and used for CO_(2)capture.The CO_(2)chemisorption capacity of the adsorbent was further enhanced by taking advantage of the nitrogenous bases contained in the BA.In the hydrothermal process,the addition of BA significantly increased the content of pyrrole nitrogen in the adsorbent.In the activation process,pyrrole nitrogen gradually changed into pyridine nitrogen and graphite nitrogen.Increased BA addition result in a higher specific surface area and microporosity of the adsorbent.The CO_(2)adsorption performance test proved that the CGFS-50%-CA sample has the strongest CO_(2)adsorption capacity at low temperature,up to 15.59 cm^(3)/g,which is mainly through physical adsorption,and the CGFS-10%-CA sample has the strongest CO_(2)adsorption capacity at high temperature,up to 7.31 cm^(3)/g,which is mainly through chemical adsorption.CO_(2)uptake of the CGFS-10%-CA sample was well maintained after 10 cycles,with regeneration efficiencies above 99%.The results indicate that the novel adsorbents with coexistence of physical and chemical adsorption have great potential for CO_(2)adsorption applications.展开更多
The gasification behaviors of coke were investigated under conditions simulating a hydrogen-rich blast furnace atmosphere,composed of N_(2),CO,CO_(2),H_(2),and H_(2)O.Systematic experimental studies were conducted to ...The gasification behaviors of coke were investigated under conditions simulating a hydrogen-rich blast furnace atmosphere,composed of N_(2),CO,CO_(2),H_(2),and H_(2)O.Systematic experimental studies were conducted to examine the effects of gasification temperature and H_(2)O content on the microstructural and macroscopic properties of coke.The results indicated that increasing temperature and H_(2)O content enhanced the gasification and dissolution loss of coke,with temperature having a more significant impact.Pore structure analysis of the gasified coke revealed that small pores and micropores predominated at 900 and 1000℃.However,at gasification temperatures above 1100℃,oversized holes formed,some of which extended into the coke's interior.The compressive strength of the coke was also assessed,showing that higher gasification temperatures or increased H_(2)O content reduced this property.This reduction is primarily due to the increased coke porosity and the degradation of the pore wall structure.X-ray diffraction analysis results suggested that higher gasification temperatures and H2O content could improve the degree of order in the carbon microcrystals of the gasified coke.展开更多
This study systematically investigated the catalytic gasification of two distinct petroleum coke(PC)using magnesium-based tailings(MT)as the catalyst.The research objectives focused on comparative analysis of gasifica...This study systematically investigated the catalytic gasification of two distinct petroleum coke(PC)using magnesium-based tailings(MT)as the catalyst.The research objectives focused on comparative analysis of gasification reactivities and elucidation of carbon microstructure evolution during PC gasification.Experimental results demonstrate that PC-B(derived from Liaohe Oilfields delayed coking)exhibited significantly higher gasification activity than PC-A(from Karamay Oilfields delayed coking),with aromatic C–H content and polycondensation index showing stronger correlations with reactivity than graphitization parameters.Notably,the MT catalyst exhibited material-dependent catalytic behaviors during gasification.MT catalyst enhanced structural ordering in PC-B by:(i)developing denser aromatic carbon layers,(ii)improving microcrystalline alignment,and(iii)elevating graphitization degree.These structural modifications contrasted sharply with PC-A’s response,where MT introduction generated active MgO species in the ash phase,boosting gasification reactivity.Conversely,in PC-B ash systems,MgO preferentially reacted with Al_(2)O_(3) to form inert MgAl_(2)O_(4) spinel,effectively deactivating the catalyst.Kinetic investigations validated the shrinking core model(SCM)as the dominant mechanism,with calculated activation energies of 172.12 kJ/mol(PC-A+5%MT)and 137.19 kJ/mol(PC-B+5%MT).展开更多
Brackish water(BW)irrigation may cause soil quality deterioration and thereby a decrease in crop yields.Here we examined the impacts of applying gasification filter cake(GFC),intercropping with Portulaca oleracea(PO),...Brackish water(BW)irrigation may cause soil quality deterioration and thereby a decrease in crop yields.Here we examined the impacts of applying gasification filter cake(GFC),intercropping with Portulaca oleracea(PO),and their combination on soil quality,nutrient uptake by plants and tomato yields under BW irrigation.The treatments evaluated included(i)freshwater irrigation(Control),(ii)BW irrigation,(iii)GFC application under BW irrigation(BW+GFC),(iv)intercropping with PO under BW irrigation(BW+PO),and(v)the combined application of GFC and PO under BW irrigation(BW+PO+GFC).Overall,the use of BW for irrigation resulted in a decline in both soil quality(assessed by a soil quality index(SQI)integrating a wide range of key soil properties including salinity,nutrient availability and microbial activities)and crop yields.Nevertheless,when subjected to BW irrigation,the application of GFC successfully prevented soil salinity.Additionally,the intercropping of PO decreased the soil sodium adsorption ratio and improved the absorption of nutrients by plants.As a result,the BW+GFC+PO treatment generally showed higher tomato yield as compared to other BW-related treatments(i.e.BW,BW+GFC and BW+PO).Compared to BW,the BW+GFC+PO treatment had an average increase of 24.7% in the total fruit yield of four Cropping Seasons.Furthermore,the BW+GFC+PO treatment consistently exhibited the highest fruit quality index(FQI).Taken together,the combined application of GFC and PO is effective in promoting soil quality and crop yields under BW irrigation.展开更多
The production of medical waste(MW)is a growing concern,particularly in light of the increasing annual generation and the exacerbating effects of the COVID-19 pandemic.Traditional techniques such as incineration and l...The production of medical waste(MW)is a growing concern,particularly in light of the increasing annual generation and the exacerbating effects of the COVID-19 pandemic.Traditional techniques such as incineration and landfilling present significant limitations.In this study,a self-designed 50 kW arc plasma reactor was employed to conduct gasification experiments on nitrile-butadiene rubber(NBR)which served as a model of MWand a mixture of NBR/SiO_(2) which served as a model of glass-containing MW,using CO_(2)as the working gas.The CO_(2)thermal plasma gasification process not only ensures the safe and efficient disposal of MW,but also facilitates its effective conversion into H_(2)and CO,achieving a carbon conversion efficiency of 94.52%.The yields of H2 and CO reached 98.52%and 81.83%,respectively,and the specific energy consumption was as low as 3.55 kW·h·kg^(-1).Furthermore,the addition of SiO_(2) was found to inhibit the gasification of NBR and cause damage to the reactor.Therefore,it is recommended that glass waste should be removed prior to the treatment of MW.The CO_(2)thermal plasma gasification technology can not only eliminate environmental and health risks posed by MW,but also convert it into syngas for further utilization.This provides a promising approach to the harmless and resource disposal of MW,while also contributing to the comprehensive utilization of greenhouse gases.展开更多
Coal pillars are critical supporting structures between underground coal gasification gasifiers.Its bearing capacity and structural stability are severely threatened by high-temperature environments.To elucidate the h...Coal pillars are critical supporting structures between underground coal gasification gasifiers.Its bearing capacity and structural stability are severely threatened by high-temperature environments.To elucidate the high-temperature deterioration mechanism of coal pillars at multiple scales,coal strength features as a function of temperature were investigated via uniaxial compression and acoustic emission equipment.The pyrolysis reaction process and microstructure evolution were characterized via X-ray diffractometer(XRD),scanning electron microscope(SEM),thermogravimetric(TG),Fourier transform infrared spectroscopy(FTIR),and computed tomography(CT)tests.Experimental results reveal a critical temperature threshold of 500℃for severe degradation of the coal bearing capacity.Specifically,both the strength and elastic modulus exhibit accelerated degradation above this temperature,with maximum reductions of 45.53%and 61.34%,respectively.Above 500℃,coal essentially undergoes a pyrolysis reaction under N_(2)and CO_(2)atmospheres.High temperatures decrease the quantity of O_(2)-based functional groups,growing aromaticity and the degree of graphitization.These changes induce dislocation and slip inside the coal crystal nucleus and then lead to deformation of the coal molecular structural units and strain energy generation.This process results in a great increase in porosity.Consequently,the stress deformation of coal increases,transforming the type of failure from brittle to ductile failure.These findings are expected to provide scientific support for UCG rock strata control.展开更多
The thermal conversion process known as biomass gasification has the potential to produce environmentally friendly fuels such as hydrogen.However,tar generation during the gasification remains an issue,affecting opera...The thermal conversion process known as biomass gasification has the potential to produce environmentally friendly fuels such as hydrogen.However,tar generation during the gasification remains an issue,affecting operational efficiency and environmental health.Biochar has been confirmed as an inexpensive and efficient catalyst for tar removal.The challenge lies in creating a highly reactive biochar which can be applied for different types of biomass with varying properties.This review discusses the factors that affect biochar’s reactivity as a catalyst for tar reforming.Additionally,incorporating biochar into a gasification scenario with raw biomass offers a practical solution by leveraging the synergistic behavior.However,this synergy could be either positive or negative:the positive synergy enhances tar removal while the negative synergy has the opposite effect.The numerous factors affecting the results of gasification are presented in this review.It is concluded that the positive synergistic effect resulted from the balance between the available reactants from biomass and biochar,the optimal gas flowrate and the active sites on the carbon surface.Understanding these interactions is crucial for optimizing biochar performance for tar removal.Ultimately,this research provides insights into biochar’s role in biomass gasification and suggests improvements for future studies to enhance the feasibility of biomass gasification with the assistance of biochar.展开更多
Soot is a flocculent carbon nanoparticle that results the imperfect combustion of fossil fuel,and numerous studies are dedicated to the reduction of soot production to alleviate the associated environmental problems.H...Soot is a flocculent carbon nanoparticle that results the imperfect combustion of fossil fuel,and numerous studies are dedicated to the reduction of soot production to alleviate the associated environmental problems.However,soot as a functional material is also widely used in energy storage and superhydrophobic materials.As a partial oxidation technology,the entrained flow coal gasification process will produce part of the soot.It is important to separate soot from the coal gasification fine slag(CGFS)and understand its structural characteristics for soot utilization.For this purpose,two industrial typical pulverized coal gasification fine slag(PCGFS)and coal-water slurry gasification fine slag(WCGFS)were selected for this study.The results showed that both fine slags were rich in soot,and the dry ash free mass fraction of soot in PCGFS and WCGFS was 6.24%and 2.91%,respectively,and the soot of PCGFS had a hollow carbon nanosphere morphology,while the soot of WCGFS showed a flocculent irregular morphology.The average fringe length,fringe tortuosity,and fringe spacing of the soot were 0.84 nm,1.21,and 0.45 nm,respectively.Compared to the WCGFS,the soot particles of PCGFS have less continuity of molecular bonds within the lattice,the larger the defects within the lattice,the fewer isolated lattice carbon layers there are.This study provides important theoretical support for understanding the structural characteristics and next applications of soot in the entrained flow coal gasification fine slag.展开更多
CGCS(coal gasification coarse slag)and desert sand composite aggregate replacing river sand for the preparation of concrete(coal gasification coarse slag and desert sand composite fine aggregate concrete,abbreviated a...CGCS(coal gasification coarse slag)and desert sand composite aggregate replacing river sand for the preparation of concrete(coal gasification coarse slag and desert sand composite fine aggregate concrete,abbreviated as CDFC)were investigated to study the effect of different CGCS dosages,the sand rate of concrete,and the dosage of fly ash(FA)in cementitious material on the mechanical properties of the concrete and the excessive zone at the aggregate interface.The experimental results show that,with the increase of CGCS admixture,the CDFC water-cement ratio decreases,and the strength shows first increase and then decrease;with the increase of concrete sand rate,the CDFC strength shows first increase and then decrease,and with the increase of FA,the CDFC strength shows first increase and then decrease,when the dosage of cementitious material is 360 kg/m^(3),the composite fine aggregate dosage is 872 kg/m^(3),and the coarse aggregate dosage is 983 kg/m^(3),the maximum compressive strength of its CGCS is 47.4 MPa.The microstructures of CGCS and hydration products were analyzed by X-ray fluorescence spectrometry(XRF),X-ray diffraction(XRD),Fourier transform infrared spectrometry(FTIR),and scanning electron microscopy(SEM).It is found that the CDFC as fine aggregate can generate hydration products such as hydrated calcium silicate gel(C-S-H)in the transition zone of the concrete interface,which can greatly improve the weak zones of the concrete,and improve the strength.展开更多
Following global catastrophic infrastructure loss(GCIL),traditional electricity networks would be damaged and unavailable for energy supply,necessitating alternative solutions to sustain critical services.These altern...Following global catastrophic infrastructure loss(GCIL),traditional electricity networks would be damaged and unavailable for energy supply,necessitating alternative solutions to sustain critical services.These alternative solutions would need to run without damaged infrastructure and would likely need to be located at the point of use,such as decentralized electricity generation from wood gas.This study explores the feasibility of using modified light duty vehicles to self-sustain electricity generation by producing wood chips for wood gasification.A 2004 Ford Falcon Fairmont was modified to power a woodchipper and an electrical generator.The vehicle successfully produced wood chips suitable for gasification with an energy return on investment(EROI)of 3.7 and sustained a stable output of 20 kW electrical power.Scalability analyses suggest such solutions could provide electricity to the critical water sanitation sector,equivalent to 4%of global electricity demand,if production of woodchippers was increased postcatastrophe.Future research could investigate the long-term durability of modified vehicles and alternative electricity generation,and quantify the scalability of wood gasification in GCIL scenarios.This work provides a foundation for developing resilient,decentralized energy systems to ensure the continuity of critical services during catastrophic events,leveraging existing vehicle infrastructure to enhance disaster preparedness.展开更多
This research focused on the feasibility of applying the forward and reverse combustion approach to the in situ gasification of lignite with the production of hydrogen-rich syngas(H_(2)and CO).The so-called forward co...This research focused on the feasibility of applying the forward and reverse combustion approach to the in situ gasification of lignite with the production of hydrogen-rich syngas(H_(2)and CO).The so-called forward combustion gasification(FCG)and reverse combustion gasification(RCG)approach in which oxygen and steam are simultaneously fed to the simulated system of underground coal gasification(UCG)was studied.A simulated system of UCG was designed and established.The underground conditions of the coal seam and strata were simulated in the system.The combustion gasification of lignite has been carried out experimentally for almost 6.5 days.The average effective content(H_(2)+CO)of syngas during the FCG phase was 62.31%and the maximum content was 70.92%.For the RCG phase the corresponding figures are 61.33%and 67.91%.Thus,the feasibility of using RCG way for UCG has been demonstrated.The temperature profiles have been provided by using of 85 thermocouples during the model experiment,which portrayed the several nephograms of thermal data in the gasifier were of significance for the prospective gasification processes.展开更多
A three-dimensional numerical model verified by previous experimental data is developed to simulate the fluidized bed gasification of refuse derived fuel （RDF）. The CaO dechlorination model obtained by the thermal g...A three-dimensional numerical model verified by previous experimental data is developed to simulate the fluidized bed gasification of refuse derived fuel （RDF）. The CaO dechlorination model obtained by the thermal gravity analysis （TGA） is coupled to investigate the process of CaO dechlorination. An Eulerian-Eulerian method is adopted to simulate the gas-solid flow and self-developed chemical reaction modules are used to simulate chemical reactions. Flow patterns, gasification results and dechlorination efficiency are obtained by numerical simulation. Meanwhile, simulations are performed to evaluate the effects of Ca/Cl molar ratio and temperature on dechlorination efficiency. The simulation results show that the presence of bubbles in the gasifier lowers the CaO dechlorination efficiency. Increasing the Ca/Cl molar ratio can enhance the dechlorination efficiency. However, with the temperature increasing, the dechlorination efficiency increases initially and then decreases. The optimal Ca/Cl molar ratio is in the range of 3. 0 to 3. 5 and the optimal temperature is 923K.展开更多
Numerical simulation study is conducted for a pressurized spouted fluidized bed coal carbonizer, in which hydrodynamics of pressurized spouted fluidized bed, chemical reactions and energy balance are taken into accoun...Numerical simulation study is conducted for a pressurized spouted fluidized bed coal carbonizer, in which hydrodynamics of pressurized spouted fluidized bed, chemical reactions and energy balance are taken into account. The effect of operating conditions such as bed pressure, air and steam mass flow ratio, temperature on product compositions in the bed is investigated. According to the calculated results, bed pressure and bed temperature have the key effects on coal semi gasification.展开更多
In the last decades the interest in the biomass gasification process has increased due to the growing attention to the use of sustainable energy. Biomass is a renewable energy source and represents a valid alternative...In the last decades the interest in the biomass gasification process has increased due to the growing attention to the use of sustainable energy. Biomass is a renewable energy source and represents a valid alternative to fossil fuels. Gasification is the thermochemical conversion of an organic material into a valuable gaseous product, called syngas, and a solid product, called char. The biomass gasification represents an efficient process for the production of power and heat and the production of hydrogen and second-generation biofuels.This paper deals with the state of the art biomass gasification technologies, evaluating advantages and disadvantages, the potential use of the syngas and the application of the biomass gasification. Syngas cleaning though fundamental to evaluate any gasification technology is not included in this paper since; in the authors＇ opinion, a dedicated review is necessary.展开更多
Two-stage underground coal gasification was studied to improve the caloric value of the syngas and to extend gas production times.A model test using the oxygen-enriched two-stage coal gasification method was carried o...Two-stage underground coal gasification was studied to improve the caloric value of the syngas and to extend gas production times.A model test using the oxygen-enriched two-stage coal gasification method was carried out.The composition of the gas produced,the time ratio of the two stages,and the role of the temperature field were analysed.The results show that oxygen-enriched two-stage gasification shortens the time of the first stage and prolongs the time of the second stage.Feed oxygen concentrations of 30%, 35%,40%,45%.60%,or 80%gave time ratios（first stage to second stage） of 1：0.12,1：0.21.1：0.51,1：0.64, 1：0.90.and 1：4.0 respectively.Cooling rates of the temperature field after steam injection decreased with time from about 19.1-27.4℃/min to 2.3-6.8℃/min.But this rate increased with increasing oxygen concentrations in the first stage.The caloric value of the syngas improves with increased oxygen concentration in the first stage.Injection of 80%oxygen-enriched air gave gas with the highest caloric value and also gave the longest production time.The caloric value of the gas obtained from the oxygenenriched two-stage gasification method lies in the range from 5.31 MJ/Nm^3 to 10.54 MJ/Nm^3.展开更多
基金supported by Youth Fund of National Natural Science Foundation of China(NO.22108175)Basic scientific research Project of colleges and universities of Liaoning Provincial Department of Educa-tion(No.LJKMZ20220798)+1 种基金National Natural Science Foundation of China(No.U1903130)Natural Science Foundation of Liaoning province(No.2021-NLTS-12-09),China,and JST Grant Number JPMJPF2104,Japan.
文摘Gasification is a highly effective technology for converting biomass into fuel gas or syngas.While various gas-ifiers have been commercialized for fuel gas production,mitigating tar formation in gasifiers remains chal-lenging.This review is devoted to summarizing the general strategies adopted in various gasifiers to reduce tar formation for high-efficiency clean gasification.For single-bed and staged-gasification processes,their low-tar strategies are typically different.In the single-bed processes,the low-tar strategies involve in-bed intensifica-tion achieved by controlling flow directions of gas and particles inside the gasifier.During the gasification,these two components often have different temperatures to facilitate thermochemical interactions between them.Meanwhile,the two-stage gasifiers are generally designed to decouple pyrolysis,gasification and tar cracking reactions for maximizing the benefits(such as yield and efficiency)realized from the interactions among these reactions.In addition to minimizing tar formation,the approach of reaction decoupling can also raise the calorific value of product gas,even without use of oxygen,and/or improve the adaptability of gasification technology to the feedstocks with various moisture contents and particle sizes.The reanalysis based on those essential low-tar strategies is expected to gain alternative insights into the reaction principles implicated in most advanced biomass gasification technologies.
基金supported by the National Natural Science Foundation of China(52306131)the Natural Science Foundation of Jiangsu Province(BK20230847)+2 种基金the Key Project of the National Natural Science Foundation of China(52336005)the Fundamental Research Funds for the Central Universities(2242024RCB0036)the Open Project Program of State Key Laboratory of Low-carbon Smart Coal-fired Power Generation and Ultra-clean Emission(D2024FK156).
文摘As a renewable energy source,the thermal conversion of poultry manure,is a promising waste treatment solution that can generate circular economic outputs such as energy and reduce greenhouse gas emissions.Currently,pressurized gasification of poultry manure is still a novel research field,especially when combined with a novel technological route of oxy-fuel gasification.Oxy-fuel gasification is a newly proposed and promising gasification technology for power generation that facilitates future carbon capture and storage.In this work,based on a commercially operated industrial-scale chicken manure gasification power plant in Singapore,we presented an interesting first exploration of the coupled pressurization technology for oxy-fuel gasification of poultry manure using CFD numerical simulation,analyzed the effects of pressure and oxygen enrichment concentration as well as the coupling mechanism between them,and discussed the conversion and emission of nitrogen-and sulfur-containing pollutants.The results indicate that under oxy-fuel gasification condition(Oxy-30,i.e.,30%O_(2)/70%CO_(2)),as the pressure increases from 0.1 to 0.5 MPa,the CO concentration in the syngas increases slightly,the H_(2)concentration increases to approximately 25%,and the CH4 concentration(less than 1%)decreases,resulting in an increase in the calorific value of syngas from 5.2 to 5.6 MJ·m^(-3).Compared to atmospheric pressure conditions,a relatively higher oxygen-enriched concentration interval(Oxy-40 to Oxy-50)under pressurized conditions is advantageous for autothermal gasification.Pressurization increases NO precursors production and also promotes homogeneous and heterogeneous reduction of NO,and provides favorable conditions for self-desulfurization.This work offers reference for the realization of a highly efficient and low-energy-consumption thermochemical treatment of livestock manure coupled with negative carbon emission technology.
基金financially supported by the National Science Foundation of China(Nos.51974212 and 52274316)the China Baowu Low Carbon Metallurgy Innovation Foundation(No.BWLCF202116)+1 种基金the Science and Technology Major Project of Wuhan(No.2023020302020572)the Foundation of Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education(No.FMRUlab23-04)。
文摘The utilization of iron coke provides a green pathway for low-carbon ironmaking.To uncover the influence mechanism of iron ore on the behavior and kinetics of iron coke gasification,the effect of iron ore on the microstructure of iron coke was investigated.Furthermore,a comparative study of the gasification reactions between iron coke and coke was conducted through non-isothermal thermogravimetric method.The findings indicate that compared to coke,iron coke exhibits an augmentation in micropores and specific surface area,and the micropores further extend and interconnect.This provides more adsorption sites for CO_(2) molecules during the gasification process,resulting in a reduction in the initial gasification temperature of iron coke.Accelerating the heating rate in non-isothermal gasification can enhance the reactivity of iron coke.The metallic iron reduced from iron ore is embedded in the carbon matrix,reducing the orderliness of the carbon structure,which is primarily responsible for the heightened reactivity of the carbon atoms.The kinetic study indicates that the random pore model can effectively represent the gasification process of iron coke due to its rich pore structure.Moreover,as the proportion of iron ore increases,the activation energy for the carbon gasification gradually decreases,from 246.2 kJ/mol for coke to 192.5 kJ/mol for iron coke 15wt%.
基金supported by the National Natural Science Foundation of China(52066007,22279048)the Major Science and Technology Project of Yunnan Province(202202AG050017).
文摘Molten salt gasification is a promising technology for biomass conversion due to its advantages of superior heat transfer and the ability of utilizing solar energy to reduce carbon emission.In this study,the characteristics of corncob CO_(2)-gasification in molten salt environments is thoroughly investigated,and the approach of introducing Fe_(2)O_(3) as catalyst to enhance the syngas yield is proposed.The results showed that the molten salts significantly promoted the conversion of corncob into gaseous products with very low tar and char yield.Compared to O_(2) and H_(2)O atmospheres,utilizing CO_(2) as gasifying agent enhanced the yield of gaseous products during the corncob gasification,especially the yields of CO and H_(2).The introduction of Fe_(2)O_(3) as a catalyst could further increase the yield of gaseous products and the cold gas efficiency(CGE),and the yield of syngas was increased into 2258.3 ml·g^(−1) with a high CGE of 105.8%in 900℃.The findings evidenced that CO_(2) gasification in the molten salt environment with Fe_(2)O_(3) addition can promote the cracking of tar,increasing the syngas yield significantly.Moreover,the energy required to drive the gasification process was calculated,and the total energy consumption was calculated as 16.83 GJ·t^(−1).The study opened up a new solution for the biomass gasification,exhibiting a great potential in distributed energy or chemical systems.
基金supported by the National Natural Science Foundation of China(22308170).
文摘Temperature is a critical factor influencing the performance of coal catalytic hydrogasification in bubbling fluidized bed gasifiers.Numerical simulations at various temperatures(1023 K,1073 K,1123 K,and 1173 K)are conducted to elucidate the mechanisms by which temperature affects bubble size,global reaction performance,and particle-scale reactivity.The simulation results indicate that bubble size increases at elevated temperatures,while H_(2)-char hydrogasification reactivity is enhanced.Particle trajectory analyses reveal that particles sized between 100 and 250μm undergo intense char hydrogasification in the dense phase,contributing to the formation of hot spots.To assess the impact of temperature on the particle-scale flow-transfer-reaction process,the dimensionless quantities of Reynolds,Nusselt,and Sherwood numbers,along with the solids dispersion coefficient,are calculated.It is found that higher temperatures inhibit bubble-induced mass and heat transfer.In general,3 MPa,1123 K,and 3-4 fluidization numbers are identified as the optimal conditions for particles ranging from 0 to350μm.These findings provide valuable insights into the inherent interactions between temperature and gas-particle reaction.
基金supported by the National Natural Science Foundation of China(22168032)the National Key Research and Development Program of China(2023YFC3904302,2023YFB4103500)the Key Projects of Ning Dong Energy and Chemical Industry Base(2023NDKJXMLX022).
文摘A new adsorbent was successfully prepared by hydrothermal treatment and chemical activation through coal gasification fine slag(CGFS)and blue algae(BA)as raw materials and used for CO_(2)capture.The CO_(2)chemisorption capacity of the adsorbent was further enhanced by taking advantage of the nitrogenous bases contained in the BA.In the hydrothermal process,the addition of BA significantly increased the content of pyrrole nitrogen in the adsorbent.In the activation process,pyrrole nitrogen gradually changed into pyridine nitrogen and graphite nitrogen.Increased BA addition result in a higher specific surface area and microporosity of the adsorbent.The CO_(2)adsorption performance test proved that the CGFS-50%-CA sample has the strongest CO_(2)adsorption capacity at low temperature,up to 15.59 cm^(3)/g,which is mainly through physical adsorption,and the CGFS-10%-CA sample has the strongest CO_(2)adsorption capacity at high temperature,up to 7.31 cm^(3)/g,which is mainly through chemical adsorption.CO_(2)uptake of the CGFS-10%-CA sample was well maintained after 10 cycles,with regeneration efficiencies above 99%.The results indicate that the novel adsorbents with coexistence of physical and chemical adsorption have great potential for CO_(2)adsorption applications.
基金the financial support provided by the National Natural Science Foundation of China(Nos.52174300 and 52404340)Natural Science Foundation of Chongqing,China(No.cstc2020jcyj-msxmX0583)+2 种基金Research Foundation of Chongqing University of Science and Technology(No.ckrc20240612)Chongqing Talent Plan Project(cstc2021ycjh-bgzxm0211)Chongqing Doctoral“Through Train”Project(No.sl202100000343).
文摘The gasification behaviors of coke were investigated under conditions simulating a hydrogen-rich blast furnace atmosphere,composed of N_(2),CO,CO_(2),H_(2),and H_(2)O.Systematic experimental studies were conducted to examine the effects of gasification temperature and H_(2)O content on the microstructural and macroscopic properties of coke.The results indicated that increasing temperature and H_(2)O content enhanced the gasification and dissolution loss of coke,with temperature having a more significant impact.Pore structure analysis of the gasified coke revealed that small pores and micropores predominated at 900 and 1000℃.However,at gasification temperatures above 1100℃,oversized holes formed,some of which extended into the coke's interior.The compressive strength of the coke was also assessed,showing that higher gasification temperatures or increased H_(2)O content reduced this property.This reduction is primarily due to the increased coke porosity and the degradation of the pore wall structure.X-ray diffraction analysis results suggested that higher gasification temperatures and H2O content could improve the degree of order in the carbon microcrystals of the gasified coke.
基金supported by Natural Science Foundation of Henan Province(Nos.242300421531)Doctor Program of Nanyang Normal University(No.2022ZX006)+1 种基金National Natural Science Cultivation Fund of Nanyang Normal University(No.2023PY013)Fundamental Research Program of Shanxi Province(No.202303021222038).
文摘This study systematically investigated the catalytic gasification of two distinct petroleum coke(PC)using magnesium-based tailings(MT)as the catalyst.The research objectives focused on comparative analysis of gasification reactivities and elucidation of carbon microstructure evolution during PC gasification.Experimental results demonstrate that PC-B(derived from Liaohe Oilfields delayed coking)exhibited significantly higher gasification activity than PC-A(from Karamay Oilfields delayed coking),with aromatic C–H content and polycondensation index showing stronger correlations with reactivity than graphitization parameters.Notably,the MT catalyst exhibited material-dependent catalytic behaviors during gasification.MT catalyst enhanced structural ordering in PC-B by:(i)developing denser aromatic carbon layers,(ii)improving microcrystalline alignment,and(iii)elevating graphitization degree.These structural modifications contrasted sharply with PC-A’s response,where MT introduction generated active MgO species in the ash phase,boosting gasification reactivity.Conversely,in PC-B ash systems,MgO preferentially reacted with Al_(2)O_(3) to form inert MgAl_(2)O_(4) spinel,effectively deactivating the catalyst.Kinetic investigations validated the shrinking core model(SCM)as the dominant mechanism,with calculated activation energies of 172.12 kJ/mol(PC-A+5%MT)and 137.19 kJ/mol(PC-B+5%MT).
基金supported by the Key Research and Development Program of Ningxia(Grant No.2023BCF01046)。
文摘Brackish water(BW)irrigation may cause soil quality deterioration and thereby a decrease in crop yields.Here we examined the impacts of applying gasification filter cake(GFC),intercropping with Portulaca oleracea(PO),and their combination on soil quality,nutrient uptake by plants and tomato yields under BW irrigation.The treatments evaluated included(i)freshwater irrigation(Control),(ii)BW irrigation,(iii)GFC application under BW irrigation(BW+GFC),(iv)intercropping with PO under BW irrigation(BW+PO),and(v)the combined application of GFC and PO under BW irrigation(BW+PO+GFC).Overall,the use of BW for irrigation resulted in a decline in both soil quality(assessed by a soil quality index(SQI)integrating a wide range of key soil properties including salinity,nutrient availability and microbial activities)and crop yields.Nevertheless,when subjected to BW irrigation,the application of GFC successfully prevented soil salinity.Additionally,the intercropping of PO decreased the soil sodium adsorption ratio and improved the absorption of nutrients by plants.As a result,the BW+GFC+PO treatment generally showed higher tomato yield as compared to other BW-related treatments(i.e.BW,BW+GFC and BW+PO).Compared to BW,the BW+GFC+PO treatment had an average increase of 24.7% in the total fruit yield of four Cropping Seasons.Furthermore,the BW+GFC+PO treatment consistently exhibited the highest fruit quality index(FQI).Taken together,the combined application of GFC and PO is effective in promoting soil quality and crop yields under BW irrigation.
基金supported by the National Key Research and Development Program of China(2016YFB0301800)the National High Technology Research and Development Program of China(2015AA020201).
文摘The production of medical waste(MW)is a growing concern,particularly in light of the increasing annual generation and the exacerbating effects of the COVID-19 pandemic.Traditional techniques such as incineration and landfilling present significant limitations.In this study,a self-designed 50 kW arc plasma reactor was employed to conduct gasification experiments on nitrile-butadiene rubber(NBR)which served as a model of MWand a mixture of NBR/SiO_(2) which served as a model of glass-containing MW,using CO_(2)as the working gas.The CO_(2)thermal plasma gasification process not only ensures the safe and efficient disposal of MW,but also facilitates its effective conversion into H_(2)and CO,achieving a carbon conversion efficiency of 94.52%.The yields of H2 and CO reached 98.52%and 81.83%,respectively,and the specific energy consumption was as low as 3.55 kW·h·kg^(-1).Furthermore,the addition of SiO_(2) was found to inhibit the gasification of NBR and cause damage to the reactor.Therefore,it is recommended that glass waste should be removed prior to the treatment of MW.The CO_(2)thermal plasma gasification technology can not only eliminate environmental and health risks posed by MW,but also convert it into syngas for further utilization.This provides a promising approach to the harmless and resource disposal of MW,while also contributing to the comprehensive utilization of greenhouse gases.
基金supported by Young Scholar Program(Category A Continuation Funding)of National Natural Science Foundation of China(No.52525401)General Program of National Natural Science Foundation of China(No.52174125)+4 种基金Outstanding Youth Cultivation Project in Shanxi Province(No.202103021222008)Major Program of National Natural Science Foundation of China(No.52334005)New Cornerstone Science Foundation through the XPLORER PRIZEShanxi-Zheda Institute of Advanced Materials and Chemical Engineering(No.2022SX-TD010)Shanxi Science and Technology Major Project(No.20201102004).
文摘Coal pillars are critical supporting structures between underground coal gasification gasifiers.Its bearing capacity and structural stability are severely threatened by high-temperature environments.To elucidate the high-temperature deterioration mechanism of coal pillars at multiple scales,coal strength features as a function of temperature were investigated via uniaxial compression and acoustic emission equipment.The pyrolysis reaction process and microstructure evolution were characterized via X-ray diffractometer(XRD),scanning electron microscope(SEM),thermogravimetric(TG),Fourier transform infrared spectroscopy(FTIR),and computed tomography(CT)tests.Experimental results reveal a critical temperature threshold of 500℃for severe degradation of the coal bearing capacity.Specifically,both the strength and elastic modulus exhibit accelerated degradation above this temperature,with maximum reductions of 45.53%and 61.34%,respectively.Above 500℃,coal essentially undergoes a pyrolysis reaction under N_(2)and CO_(2)atmospheres.High temperatures decrease the quantity of O_(2)-based functional groups,growing aromaticity and the degree of graphitization.These changes induce dislocation and slip inside the coal crystal nucleus and then lead to deformation of the coal molecular structural units and strain energy generation.This process results in a great increase in porosity.Consequently,the stress deformation of coal increases,transforming the type of failure from brittle to ductile failure.These findings are expected to provide scientific support for UCG rock strata control.
基金supported by JST Grant Number JPMJPF2104,Japan.Az Zahra and Alahakoon gratefully acknowledge MEXT of Japan for the scholarship.
文摘The thermal conversion process known as biomass gasification has the potential to produce environmentally friendly fuels such as hydrogen.However,tar generation during the gasification remains an issue,affecting operational efficiency and environmental health.Biochar has been confirmed as an inexpensive and efficient catalyst for tar removal.The challenge lies in creating a highly reactive biochar which can be applied for different types of biomass with varying properties.This review discusses the factors that affect biochar’s reactivity as a catalyst for tar reforming.Additionally,incorporating biochar into a gasification scenario with raw biomass offers a practical solution by leveraging the synergistic behavior.However,this synergy could be either positive or negative:the positive synergy enhances tar removal while the negative synergy has the opposite effect.The numerous factors affecting the results of gasification are presented in this review.It is concluded that the positive synergistic effect resulted from the balance between the available reactants from biomass and biochar,the optimal gas flowrate and the active sites on the carbon surface.Understanding these interactions is crucial for optimizing biochar performance for tar removal.Ultimately,this research provides insights into biochar’s role in biomass gasification and suggests improvements for future studies to enhance the feasibility of biomass gasification with the assistance of biochar.
基金supported by the National Natural Science Foundation of China(22168032,21968024)the National Key Research and Development Program of China(2023YFC3904302).
文摘Soot is a flocculent carbon nanoparticle that results the imperfect combustion of fossil fuel,and numerous studies are dedicated to the reduction of soot production to alleviate the associated environmental problems.However,soot as a functional material is also widely used in energy storage and superhydrophobic materials.As a partial oxidation technology,the entrained flow coal gasification process will produce part of the soot.It is important to separate soot from the coal gasification fine slag(CGFS)and understand its structural characteristics for soot utilization.For this purpose,two industrial typical pulverized coal gasification fine slag(PCGFS)and coal-water slurry gasification fine slag(WCGFS)were selected for this study.The results showed that both fine slags were rich in soot,and the dry ash free mass fraction of soot in PCGFS and WCGFS was 6.24%and 2.91%,respectively,and the soot of PCGFS had a hollow carbon nanosphere morphology,while the soot of WCGFS showed a flocculent irregular morphology.The average fringe length,fringe tortuosity,and fringe spacing of the soot were 0.84 nm,1.21,and 0.45 nm,respectively.Compared to the WCGFS,the soot particles of PCGFS have less continuity of molecular bonds within the lattice,the larger the defects within the lattice,the fewer isolated lattice carbon layers there are.This study provides important theoretical support for understanding the structural characteristics and next applications of soot in the entrained flow coal gasification fine slag.
基金Funded by the Scientific Research Program of Jilin Provincial Department of Education(No.JJKH20250981KJ)。
文摘CGCS(coal gasification coarse slag)and desert sand composite aggregate replacing river sand for the preparation of concrete(coal gasification coarse slag and desert sand composite fine aggregate concrete,abbreviated as CDFC)were investigated to study the effect of different CGCS dosages,the sand rate of concrete,and the dosage of fly ash(FA)in cementitious material on the mechanical properties of the concrete and the excessive zone at the aggregate interface.The experimental results show that,with the increase of CGCS admixture,the CDFC water-cement ratio decreases,and the strength shows first increase and then decrease;with the increase of concrete sand rate,the CDFC strength shows first increase and then decrease,and with the increase of FA,the CDFC strength shows first increase and then decrease,when the dosage of cementitious material is 360 kg/m^(3),the composite fine aggregate dosage is 872 kg/m^(3),and the coarse aggregate dosage is 983 kg/m^(3),the maximum compressive strength of its CGCS is 47.4 MPa.The microstructures of CGCS and hydration products were analyzed by X-ray fluorescence spectrometry(XRF),X-ray diffraction(XRD),Fourier transform infrared spectrometry(FTIR),and scanning electron microscopy(SEM).It is found that the CDFC as fine aggregate can generate hydration products such as hydrated calcium silicate gel(C-S-H)in the transition zone of the concrete interface,which can greatly improve the weak zones of the concrete,and improve the strength.
基金This work was funded in part by the Alliance to Feed the Earth in Disasters(ALLFED).
文摘Following global catastrophic infrastructure loss(GCIL),traditional electricity networks would be damaged and unavailable for energy supply,necessitating alternative solutions to sustain critical services.These alternative solutions would need to run without damaged infrastructure and would likely need to be located at the point of use,such as decentralized electricity generation from wood gas.This study explores the feasibility of using modified light duty vehicles to self-sustain electricity generation by producing wood chips for wood gasification.A 2004 Ford Falcon Fairmont was modified to power a woodchipper and an electrical generator.The vehicle successfully produced wood chips suitable for gasification with an energy return on investment(EROI)of 3.7 and sustained a stable output of 20 kW electrical power.Scalability analyses suggest such solutions could provide electricity to the critical water sanitation sector,equivalent to 4%of global electricity demand,if production of woodchippers was increased postcatastrophe.Future research could investigate the long-term durability of modified vehicles and alternative electricity generation,and quantify the scalability of wood gasification in GCIL scenarios.This work provides a foundation for developing resilient,decentralized energy systems to ensure the continuity of critical services during catastrophic events,leveraging existing vehicle infrastructure to enhance disaster preparedness.
基金The work has been supported by the National High Technology Research and Development Program 863 of China(2011AA050106)the Fundamental Research Funds for the Central Universities(2012YH01).
文摘This research focused on the feasibility of applying the forward and reverse combustion approach to the in situ gasification of lignite with the production of hydrogen-rich syngas(H_(2)and CO).The so-called forward combustion gasification(FCG)and reverse combustion gasification(RCG)approach in which oxygen and steam are simultaneously fed to the simulated system of underground coal gasification(UCG)was studied.A simulated system of UCG was designed and established.The underground conditions of the coal seam and strata were simulated in the system.The combustion gasification of lignite has been carried out experimentally for almost 6.5 days.The average effective content(H_(2)+CO)of syngas during the FCG phase was 62.31%and the maximum content was 70.92%.For the RCG phase the corresponding figures are 61.33%and 67.91%.Thus,the feasibility of using RCG way for UCG has been demonstrated.The temperature profiles have been provided by using of 85 thermocouples during the model experiment,which portrayed the several nephograms of thermal data in the gasifier were of significance for the prospective gasification processes.
基金The National Natural Science Foundation of China(No.51476032)
文摘A three-dimensional numerical model verified by previous experimental data is developed to simulate the fluidized bed gasification of refuse derived fuel （RDF）. The CaO dechlorination model obtained by the thermal gravity analysis （TGA） is coupled to investigate the process of CaO dechlorination. An Eulerian-Eulerian method is adopted to simulate the gas-solid flow and self-developed chemical reaction modules are used to simulate chemical reactions. Flow patterns, gasification results and dechlorination efficiency are obtained by numerical simulation. Meanwhile, simulations are performed to evaluate the effects of Ca/Cl molar ratio and temperature on dechlorination efficiency. The simulation results show that the presence of bubbles in the gasifier lowers the CaO dechlorination efficiency. Increasing the Ca/Cl molar ratio can enhance the dechlorination efficiency. However, with the temperature increasing, the dechlorination efficiency increases initially and then decreases. The optimal Ca/Cl molar ratio is in the range of 3. 0 to 3. 5 and the optimal temperature is 923K.
文摘Numerical simulation study is conducted for a pressurized spouted fluidized bed coal carbonizer, in which hydrodynamics of pressurized spouted fluidized bed, chemical reactions and energy balance are taken into account. The effect of operating conditions such as bed pressure, air and steam mass flow ratio, temperature on product compositions in the bed is investigated. According to the calculated results, bed pressure and bed temperature have the key effects on coal semi gasification.
文摘In the last decades the interest in the biomass gasification process has increased due to the growing attention to the use of sustainable energy. Biomass is a renewable energy source and represents a valid alternative to fossil fuels. Gasification is the thermochemical conversion of an organic material into a valuable gaseous product, called syngas, and a solid product, called char. The biomass gasification represents an efficient process for the production of power and heat and the production of hydrogen and second-generation biofuels.This paper deals with the state of the art biomass gasification technologies, evaluating advantages and disadvantages, the potential use of the syngas and the application of the biomass gasification. Syngas cleaning though fundamental to evaluate any gasification technology is not included in this paper since; in the authors＇ opinion, a dedicated review is necessary.
基金financial support of the National Natural Science Foundation of China(No.50876112)the Fundamental Research Funds for the Central Universities (No.2009QH13)the Program of International S&T Cooperation (No.2009DFR60180,No.2010DFR60610)
文摘Two-stage underground coal gasification was studied to improve the caloric value of the syngas and to extend gas production times.A model test using the oxygen-enriched two-stage coal gasification method was carried out.The composition of the gas produced,the time ratio of the two stages,and the role of the temperature field were analysed.The results show that oxygen-enriched two-stage gasification shortens the time of the first stage and prolongs the time of the second stage.Feed oxygen concentrations of 30%, 35%,40%,45%.60%,or 80%gave time ratios（first stage to second stage） of 1：0.12,1：0.21.1：0.51,1：0.64, 1：0.90.and 1：4.0 respectively.Cooling rates of the temperature field after steam injection decreased with time from about 19.1-27.4℃/min to 2.3-6.8℃/min.But this rate increased with increasing oxygen concentrations in the first stage.The caloric value of the syngas improves with increased oxygen concentration in the first stage.Injection of 80%oxygen-enriched air gave gas with the highest caloric value and also gave the longest production time.The caloric value of the gas obtained from the oxygenenriched two-stage gasification method lies in the range from 5.31 MJ/Nm^3 to 10.54 MJ/Nm^3.
