Gasification of furfural residue with coal can realize its efficient and clean utilization.But the high alkali metal content in furfural slag is easy to cause the corrosion of gasifier refractory.Two gasification coal...Gasification of furfural residue with coal can realize its efficient and clean utilization.But the high alkali metal content in furfural slag is easy to cause the corrosion of gasifier refractory.Two gasification coals with different silica alumina ratio and a furfural residue were selected in the study.The effects of furfural residue additions on corrosion of silica brick,corundum brick,high alumina brick and mullite brick were investigated by using XRD,SEM-EDS and Factsage Software,and the corrosion mechanism was analyzed.With increasing furfural residue addition,the permeability of the slags to high-aluminium-bearing refractories first decreases and then increases,while the permeability on silica brick shows a slight decrease trend.Leucite(KAlSi_(2)O_(6))with high-melting temperature is generated from the reaction of K_(2)O and SiO_(2)in slag with Al_(2)O_(3)in refractories after furfural residue is added,which hinders the infiltration of slag in refractories.Kaliophilite(KAlSiO_(4))of low-melting point is formed when K_(2)O content increases,and this contributes to the infiltration of slag in refractories.The acid-base reaction between slag and silica brick is distinctly occurred,more slag reacts with SiO_(2)in the silicon brick,resulting in a decrease in the amount of slag infiltrating into the silicon brick as furfural residue is added.The corrosion of silica brick is mainly caused by the acid-base reaction,while the corrosion of three alumina based refractory bricks of corundum,mullite and high alumina brick is determined by slag infiltration.A linear correlation between the percolation rate and slag viscosity is established,the slag permeability increases with decreasing viscosity,resulting in stronger permeability for the high Si/Al ratio slag with lower viscosity.展开更多
Co-gasification of coal and biomass is emerging as potential clean fuel technology to achieve high thermodynamic efficiency with relatively low CO2 emission. The coal and biomass have been exclusively gasified more th...Co-gasification of coal and biomass is emerging as potential clean fuel technology to achieve high thermodynamic efficiency with relatively low CO2 emission. The coal and biomass have been exclusively gasified more than a century to obtain gas–liquid fuels and the production of chemicals. Co-gasification has higher efficiency than the solitary coal gasification because the cellulose, hemicellulose and lignin content of biomass help to ignite and enhance the rate of gasification. It is suggested that the extensive research on carbon reactivity pattern, heat release, reaction kinetics, etc. may support to reduce the uncertainties in the co-gasification performance of coal and biomass blends, particularly in India. The prospects of co-gasification technology in Indian context have been discussed considering the abundance of varieties of coal and biomass. The suitability of existing gasifier procedures and their limitations with operating parameters like temperature, residence time, density optimisation, feed rate, agglomeration intensity, the tar formation and techno-economics involved are described. Also, this paper reviews the research highlights of the history of co-gasification and the advancement in upcoming challenges like a design of gasifier, access and preparation of biomass, disposal of residue, environmental concerns and reassurance to the operators for execution of large and small-scale projects.展开更多
As one of promising clean coal technologies used to reduce pollutant emission and CO2 discharge, co gasification has been extensively investigated. In this paper, a new co-gasification technology using coal and natura...As one of promising clean coal technologies used to reduce pollutant emission and CO2 discharge, co gasification has been extensively investigated. In this paper, a new co-gasification technology using coal and natural gas was developed. The distinct advantages of this technology are the excellent fuel flexibility and the availability to establish the gasifier by reconstructing the blast furnace or similar shaft furnace. Based on the concept of the new co-gasification technology, lab-scale experiments and modeling study were carried out. The obtained results indicate that gasification is undertaken at ideal thermodynamic environment where quasi-equilibrium could be reached without catalysts. The modeling results are in agreement with experimental data, demonstrating the validity of the model and that Aspen Plus is a useful tool for the analysis of the co-gasification process. Furthermore, the effect of major operation parameters, including oxygen flow rate and steam flow rate, on co-gasification process was investigated using the developed model.展开更多
A new co-gasification technology was proposed. The core of this co-gasification technology is a gasifier capable of being operated on a wide range of fuels and being reconstructed from blast furnace or shaft furnace. ...A new co-gasification technology was proposed. The core of this co-gasification technology is a gasifier capable of being operated on a wide range of fuels and being reconstructed from blast furnace or shaft furnace. Based on this innovative concept, the lab-scale experiment and modeling study were carried out to demonstrate its technical validity and thermodynamic characteristics. The obtained results indicate that co-gasification process can be undertaken under ideal thermodynamic conditions where quasi-equilibrium could be reached without catalysts and Aspen Plus is a useful tool for this process development. Furthermore, potential applications of co-gasification were discussed.展开更多
The present study aims to investigate the physico-chemical structural evolution characteristics of char structure of CO_(2) atmosphere torrefaction pretreated sludge with Yangchangwan bituminous coal(YC)during co-gasi...The present study aims to investigate the physico-chemical structural evolution characteristics of char structure of CO_(2) atmosphere torrefaction pretreated sludge with Yangchangwan bituminous coal(YC)during co-gasification.The co-gasification reactivity of torrefied sludge and YC was measured using a thermogravimetric analyzer.The co-gasification reactivity of torrefied sludge with YC was thoroughly explored in depth by in situ heating stage microscope coupled with traditional characterization means of char sample(Scanning electron microscope,nitrogen adsorption analyzer,laser Raman spectroscopy).The results show that the gasification reaction rate of sludge treated under CO_(2) atmosphere and coal blended char was better than other char samples at 1100–1200℃.The torrefied sludge under CO_(2) atmosphere promoted its thermal decomposition to the maximum extent,so that it eventually was transformed into a large number of small broken particles.The specific surface area and ID1/IG ratio of blended char of torrefied sludge under CO_(2) atmosphere and YC were 1.70 and 1.07 times higher than that of YC,respectively.The in situ technique revealed that YC char with the addition of torrefied sludge undergo gasification by shrinking core modes and the presence of obvious ash melting flow phenomenon.It was more obvious than that of YC.展开更多
Lignin and cellulose chemicals were used as artificial biomass components to make-up a simulated biomass. Alkali and Alkaline Earth Metal (AAEM) as well as volatile matter contents in these chemicals were much differe...Lignin and cellulose chemicals were used as artificial biomass components to make-up a simulated biomass. Alkali and Alkaline Earth Metal (AAEM) as well as volatile matter contents in these chemicals were much different from each other. Co-gasification of coal with simulated biomass shows improved conversion characteristics in comparison to the average calculated from separate conversion of coal and simulated biomass. Two conversion synergetic peaks were observed whereby the first peak occurred around 400℃ while the second one occurred above 800℃. Although co-gasification of coal with lignin that has high AAEM content also shows two synergy peaks, the one at higher temperature is dominant. Co-gasification of coal with cellulose shows only a single synergy peak around 400℃ indicating that synergy at low temperature is related with interaction of volatiles. Investigation of morphology changes during gasification of lignin and coal, suggests that their low reactivity is associated with their solid shape maintained even at high temperature.展开更多
Co-gasification of industrial sludge(IS)and coal was an effective approach to achieve harmless and sustainable utilization of IS.The long-term and stable operation of a co-gasification largely depends on fluidity of c...Co-gasification of industrial sludge(IS)and coal was an effective approach to achieve harmless and sustainable utilization of IS.The long-term and stable operation of a co-gasification largely depends on fluidity of coal-ash slag.Herein,the effects of IS addition on the crystallization and viscosity of Shuangmazao(SMZ)coal were investigated by means of high temperature stage coupled with an optical microscope(HTSOM),a scanning electron microscopy coupled with an energy dispersive Xray spectrometry(SEM-EDS),X-ray diffraction(XRD),a Fourier transform infrared spectrometer(FTIR),and FactSage software.The results showed that when the proportion of IS was less than 60%,with the addition of IS,the slag existed in an amorphous form.This was due to the high content of SiO_(2) and Al_(2)O_(3) in SMZ ash and blended ash,which had a high glass-forming ability(GFA).The slag formed at a high temperature had a higher polymerization degree and viscosity,which led to a decrease in the migration ability between ions,and ultimately made the slag difficult to crystallize during the cooling.When the proportion of IS was higher than 60%,the addition of IS increased the CaO and FeO content in the system.As network modifiers,CaO and FeO could provide O^(2−)at a high temperature,which reacted with silicate network structure and continuously destroyed the complexity of network structure,thus reducing the polymerization degree and viscosity of slag.At this time,the migration ability between ions was enhanced,and needle-shaped/rod-shaped crystals were precipitated during the cooling process.Finally,the viscosity calculated by simulation and Einstein-Roscoe empirical formula demonstrated that the addition of IS could significantly improve the fluidity of coal ash and meet the requirements of the liquid slag-tapping gasifier.The purpose of this work was to provide theoretical support for slag flow mechanisms during the gasifier slagging-tapping process and the resource treatment of industrial solid waste.展开更多
Potato is the fifth largest agricultural crop in Canada and contributes to the generation of an abundant amount of potato peel.However,disposal/recycling this peel remains a challenge due to the stringent environmenta...Potato is the fifth largest agricultural crop in Canada and contributes to the generation of an abundant amount of potato peel.However,disposal/recycling this peel remains a challenge due to the stringent environmental regulations.Consequently,there is a lack of an appropriate recycling and valorization methods of potato peel.Gasification is an effective technology for producing syngas and an ecofriendly waste disposal approach.Syngas is an important industrial intermediate to produce synthetic fuels and chemicals.To develop an ecofriendly and cost-effective valorization approach for potato peel,this study used a mixture of woody biomass(i.e.,wood chips)and potato peel to produce syngas by co-gasification using O_(2) as the gasifying agent at a constant equivalence ratio of 0.3 using Aspen Plus simulation software.The influences of gasification temperature and wood chip/potato peel weight ratio on the carbon conversion efficiency(CCE),and product gas composition(molar fraction)and lower heating value(LHV)of product gas were investigated.This simulation indicated that a positive synergistic interaction occurs between wood chips and potato peel in co-gasification process in terms of an increase in CCE by comparing the arithmetic value and real value at all simulated wood chip to potato peel weight ratios(44.9%to 85.8%,46.5%to 76.2%,and 48.1%to 78.6%at ratios of 25:75,50:50,and 75:25,respectively,for wood chips to potato peel).While the molar fraction of H_(2) and CO decreased continuously with increase in the weight percentage of wood chips in the wood chip-potato peel mixture from 0 wt%to 100 wt%(H_(2),at 42.1 mol%to 41.4 mol%;and CO at 44.0 mol%to 40.4 mol%),accompanied by a decrease of the LHV of the product gas(10.3 to 9.78 MJ·Nm^(−3)).The study concluded that co-gasification for producing syngas is feasible and environmental-friendly option to recycle and valorize potato peel.展开更多
Some ash related problems,such as slagging at furnace bottom and fouling at the air pre-heater surface,are frequently encountered during circulating fluidized bed gasification(CFBG)of Zhundong coal.Low ash fusion temp...Some ash related problems,such as slagging at furnace bottom and fouling at the air pre-heater surface,are frequently encountered during circulating fluidized bed gasification(CFBG)of Zhundong coal.Low ash fusion temperatures(AFTs)and intense sodium release should be responsible for those problems.In industry,coal blending is deemed to be a feasible method to both improve AFTs and control sodium release.In this work,Wuhai coal was selected as blending coal.The ratio is varied from 0%to 40%by mass with 10%interval.The mixed samples were gasified by steam at 950°C in a lab-scale furnace.Some key indices,such as sodium release behaviors,ash slagging characteristics and char gasification performances,were investigated by ICP-OES,AFTs,XRD and TG analyzers,respectively.The results indicated that coal blending could significantly decrease sodium release behaviors.For ash slagging characteristics,it is surprised to find that three out of four AFTs(deformation temperature,softening temperature,hemispherical temperature)show an U-shaped correlation with blending ratio,indicating that a low ratio possibly causes more severe ash slagging problem.It is ascribed to the formation of substantial percentage of fusible Na-containing silicates and aluminosilicates.In addition,coal blending greatly increases ST-DT,implying that the ability of resistance to bed temperature fluctuation is markedly enhanced.Due to the high level of alkali and alkaline species,the synergistic effect is clearly observed during co-gasification.Taking all key indices into consideration,30%blending ratio of Wuhai coal is recommended.展开更多
In this work,to efficiently utilize waste fruit and low-rank coal for the hydrogen(H_(2))-rich syngas production,steam co-gasification of banana peel(BP)and brown coal(BC)was studied in a fixed-bed reactor.The results...In this work,to efficiently utilize waste fruit and low-rank coal for the hydrogen(H_(2))-rich syngas production,steam co-gasification of banana peel(BP)and brown coal(BC)was studied in a fixed-bed reactor.The results showed that the gasification rate of BC was highly enhanced after mixing it with BP and the obvious synergistic effect was observed in all investigated three mixing weight ratios(i.e.,1:1,1:4,4:1),resulting in a higher carbon conversion as well as a H_(2)-rich gas production yield for the co-gasification.However,the extent of promotion by synergistic effect was affected by the reaction temperature,mixing ratio,and steam amount.It was found that the high potassium(K)species content in the BP provided the catalytic effect not only on water-gas shift reaction but also on tar reforming/cracking,thereby enhancing the gasification of BC.In addition,it is confirmed that steam should be an important factor to promote the synergistic effect and H_(2)-rich gas production.展开更多
Co-thermal chemical conversion of coal and biomass is one of the important ways to realize efficient and clean utilization of coal.In this study,a typical Ningdong coal-Yangchangwan bituminous coal and cow manure were...Co-thermal chemical conversion of coal and biomass is one of the important ways to realize efficient and clean utilization of coal.In this study,a typical Ningdong coal-Yangchangwan bituminous coal and cow manure were used to study the synergistic effect of intrinsic alkali,alkaline earth metals(AAEM)and organic matter on the co-gasification of coal and biomass by thermogravimetry analyzer(TG).The results showed that AAEM had obvious synergistic promotion effect on the gasification of a bituminous coal-cow manure mixture in the isothermal gasification(1000℃),whereas the organic matter will show the opposite effect on the process.To further investigate the effect of organic matter on the gasification process,the influence of organic matter on non-isothermal(25-1000℃)gasification reaction was investigated with heating rate of 10℃/min,the kinetic parameters of the gasification reaction were obtained by Coats-Redfern method.The increase of biomass mass fraction in the sample facilitates the migration of alkali metals from the material to the solid phase.The possible mechanism of the synergistic effect of intrinsic AAEM/organic matter on the co-gasification process was proposed.展开更多
The co-gasification of sewage sludge and palm oil empty fruit bunch(EFB) in supercritical water(SCW) was conducted at 400 °C with a pressure of over 25 MPa. This study aimed to investigate the influence of EFB ad...The co-gasification of sewage sludge and palm oil empty fruit bunch(EFB) in supercritical water(SCW) was conducted at 400 °C with a pressure of over 25 MPa. This study aimed to investigate the influence of EFB addition on the syngas production and its composition. The heavy metal distribution and the leaching potential of the solid residue were also assessed. The results showed that syngas yield significantly increased with the addition of EFB into the feedstock. The cold gas efficiency(CGE) and carbon efficiency(CE) of co-gasification were higher than those of individual gasification. The actual syngas production from co-gasification of sludge and EFB was 45% higher than the theoretical total volume. The results indicated that the addition of EFB to sludge had the synergetic promotion effect on syngas production from sludge and EFB in supercritical water. This enhancement might be due to the dissolution of alkali metals from EFB and the adjustment of organic ratio. In addition, higher percentage of heavy metals were deposited and stabilized in the solid residue after SCWG. The leaching concentration of heavy metals from the solid residues was decreased to a level below the standard limit which enables it to be safely disposed of in landfill. In conclusion, the EFB addition has been proved to promote syngas production,as well as, stabilize the heavy metal in solid residues during co-SCWG.展开更多
This study investigates the potential of solid fuel blending as an effective approach to manipulate ash melting behaviour to alleviate ashrelated problems during gasification,thus improving design,operability and safe...This study investigates the potential of solid fuel blending as an effective approach to manipulate ash melting behaviour to alleviate ashrelated problems during gasification,thus improving design,operability and safety.The ash fusion characteristics of Qinghai bituminous coal together with Fushun,Xinghua and Laoheishan oil shales(and their respective blends)were quantified using a novel picture analysis and graphing method,which incorporates conventional ash fusion study,dilatometry and sintering strength test,in a CO/CO_(2)atmosphere.This imagebased characterisation method was used to monitor and quantify the complete melting behaviour of ash samples from room temperature to 1520℃.The impacts of blending on compositional changes during heating were determined experimentally via Xray diffraction and validated computationally using FactSage.Results showed that the melting point of Qinghai coal ash to be the lowest at 1116℃,but would increase up to 1208℃,1161℃and 1160℃with the addition of 30%50%of Laoheishan,Fushun,and Xinghua oil shales,respectively.The formation of highmelting anorthite and mullite structures inhibits the formation of lowmelting hercynite.However,the sintering point of Qinghai coal ash was seen to decrease from 1005℃to 855℃,834℃,and 819℃in the same blends due to the formation of lowmelting aluminosilicate.Results also showed that blending directly influences the sintering strength during the various stages of melting.The key finding from this study is that it is possible to mitigate against the severe ash slagging and fouling issue arising from high calcium and iron coals by cogasification with a high silicaalumina oil shale.Moreover,blending coals with oil shales can also modify the ash melting behaviour of fuels to create the optimal ash chemistry that meets the design specification of the gasifier,without adversely affecting thermal performance.展开更多
This paper describes a single fluidized bed by the two-step gasification of the working method, process and biomass and coal co-gasification by a certain proportion of the results of a typical run. The results show th...This paper describes a single fluidized bed by the two-step gasification of the working method, process and biomass and coal co-gasification by a certain proportion of the results of a typical run. The results show that the biomass gasifi-cation technology for raw materials has a wide adaptability, the tar content in the gas is less than 10mg/m3,component in it ,the H2+CO>70%, H2/C ≈1~2,especially suitable for biomass from hydrogen, synthetic alcohol fuel, is a promising approach.展开更多
基金Shandong Province Natural Science Foundation,China(ZR2020KB014,ZR2022QB206)the National Natural Science Foundation of China(22178001)+1 种基金Anhui Provincial Natural Science Foundation(2308085Y19)Research Project for Outstanding Youth of Department of Education of Anhui Province(2022AH030045).
文摘Gasification of furfural residue with coal can realize its efficient and clean utilization.But the high alkali metal content in furfural slag is easy to cause the corrosion of gasifier refractory.Two gasification coals with different silica alumina ratio and a furfural residue were selected in the study.The effects of furfural residue additions on corrosion of silica brick,corundum brick,high alumina brick and mullite brick were investigated by using XRD,SEM-EDS and Factsage Software,and the corrosion mechanism was analyzed.With increasing furfural residue addition,the permeability of the slags to high-aluminium-bearing refractories first decreases and then increases,while the permeability on silica brick shows a slight decrease trend.Leucite(KAlSi_(2)O_(6))with high-melting temperature is generated from the reaction of K_(2)O and SiO_(2)in slag with Al_(2)O_(3)in refractories after furfural residue is added,which hinders the infiltration of slag in refractories.Kaliophilite(KAlSiO_(4))of low-melting point is formed when K_(2)O content increases,and this contributes to the infiltration of slag in refractories.The acid-base reaction between slag and silica brick is distinctly occurred,more slag reacts with SiO_(2)in the silicon brick,resulting in a decrease in the amount of slag infiltrating into the silicon brick as furfural residue is added.The corrosion of silica brick is mainly caused by the acid-base reaction,while the corrosion of three alumina based refractory bricks of corundum,mullite and high alumina brick is determined by slag infiltration.A linear correlation between the percolation rate and slag viscosity is established,the slag permeability increases with decreasing viscosity,resulting in stronger permeability for the high Si/Al ratio slag with lower viscosity.
基金funding agencies for grant-in-aid S&T projects such as 11th and 12th five-year plan projects of CSIR for co-gasification and multi-feed gasification project of DRDO under which research has been carried out
文摘Co-gasification of coal and biomass is emerging as potential clean fuel technology to achieve high thermodynamic efficiency with relatively low CO2 emission. The coal and biomass have been exclusively gasified more than a century to obtain gas–liquid fuels and the production of chemicals. Co-gasification has higher efficiency than the solitary coal gasification because the cellulose, hemicellulose and lignin content of biomass help to ignite and enhance the rate of gasification. It is suggested that the extensive research on carbon reactivity pattern, heat release, reaction kinetics, etc. may support to reduce the uncertainties in the co-gasification performance of coal and biomass blends, particularly in India. The prospects of co-gasification technology in Indian context have been discussed considering the abundance of varieties of coal and biomass. The suitability of existing gasifier procedures and their limitations with operating parameters like temperature, residence time, density optimisation, feed rate, agglomeration intensity, the tar formation and techno-economics involved are described. Also, this paper reviews the research highlights of the history of co-gasification and the advancement in upcoming challenges like a design of gasifier, access and preparation of biomass, disposal of residue, environmental concerns and reassurance to the operators for execution of large and small-scale projects.
文摘As one of promising clean coal technologies used to reduce pollutant emission and CO2 discharge, co gasification has been extensively investigated. In this paper, a new co-gasification technology using coal and natural gas was developed. The distinct advantages of this technology are the excellent fuel flexibility and the availability to establish the gasifier by reconstructing the blast furnace or similar shaft furnace. Based on the concept of the new co-gasification technology, lab-scale experiments and modeling study were carried out. The obtained results indicate that gasification is undertaken at ideal thermodynamic environment where quasi-equilibrium could be reached without catalysts. The modeling results are in agreement with experimental data, demonstrating the validity of the model and that Aspen Plus is a useful tool for the analysis of the co-gasification process. Furthermore, the effect of major operation parameters, including oxygen flow rate and steam flow rate, on co-gasification process was investigated using the developed model.
文摘A new co-gasification technology was proposed. The core of this co-gasification technology is a gasifier capable of being operated on a wide range of fuels and being reconstructed from blast furnace or shaft furnace. Based on this innovative concept, the lab-scale experiment and modeling study were carried out to demonstrate its technical validity and thermodynamic characteristics. The obtained results indicate that co-gasification process can be undertaken under ideal thermodynamic conditions where quasi-equilibrium could be reached without catalysts and Aspen Plus is a useful tool for this process development. Furthermore, potential applications of co-gasification were discussed.
基金supported by the Scientific Research Fund Project of Yunnan Provincial Department of Education(2022J0756)the National Natural Science Foundation of China(32260321,21968024).
文摘The present study aims to investigate the physico-chemical structural evolution characteristics of char structure of CO_(2) atmosphere torrefaction pretreated sludge with Yangchangwan bituminous coal(YC)during co-gasification.The co-gasification reactivity of torrefied sludge and YC was measured using a thermogravimetric analyzer.The co-gasification reactivity of torrefied sludge with YC was thoroughly explored in depth by in situ heating stage microscope coupled with traditional characterization means of char sample(Scanning electron microscope,nitrogen adsorption analyzer,laser Raman spectroscopy).The results show that the gasification reaction rate of sludge treated under CO_(2) atmosphere and coal blended char was better than other char samples at 1100–1200℃.The torrefied sludge under CO_(2) atmosphere promoted its thermal decomposition to the maximum extent,so that it eventually was transformed into a large number of small broken particles.The specific surface area and ID1/IG ratio of blended char of torrefied sludge under CO_(2) atmosphere and YC were 1.70 and 1.07 times higher than that of YC,respectively.The in situ technique revealed that YC char with the addition of torrefied sludge undergo gasification by shrinking core modes and the presence of obvious ash melting flow phenomenon.It was more obvious than that of YC.
文摘Lignin and cellulose chemicals were used as artificial biomass components to make-up a simulated biomass. Alkali and Alkaline Earth Metal (AAEM) as well as volatile matter contents in these chemicals were much different from each other. Co-gasification of coal with simulated biomass shows improved conversion characteristics in comparison to the average calculated from separate conversion of coal and simulated biomass. Two conversion synergetic peaks were observed whereby the first peak occurred around 400℃ while the second one occurred above 800℃. Although co-gasification of coal with lignin that has high AAEM content also shows two synergy peaks, the one at higher temperature is dominant. Co-gasification of coal with cellulose shows only a single synergy peak around 400℃ indicating that synergy at low temperature is related with interaction of volatiles. Investigation of morphology changes during gasification of lignin and coal, suggests that their low reactivity is associated with their solid shape maintained even at high temperature.
基金supported by the project of Key Research Plan of Ningxia(2019BEB04030 and 2019BCH01001)the project of CHN Energy Ningxia Coal Industry Co.,Ltd.(NXMY2112).
文摘Co-gasification of industrial sludge(IS)and coal was an effective approach to achieve harmless and sustainable utilization of IS.The long-term and stable operation of a co-gasification largely depends on fluidity of coal-ash slag.Herein,the effects of IS addition on the crystallization and viscosity of Shuangmazao(SMZ)coal were investigated by means of high temperature stage coupled with an optical microscope(HTSOM),a scanning electron microscopy coupled with an energy dispersive Xray spectrometry(SEM-EDS),X-ray diffraction(XRD),a Fourier transform infrared spectrometer(FTIR),and FactSage software.The results showed that when the proportion of IS was less than 60%,with the addition of IS,the slag existed in an amorphous form.This was due to the high content of SiO_(2) and Al_(2)O_(3) in SMZ ash and blended ash,which had a high glass-forming ability(GFA).The slag formed at a high temperature had a higher polymerization degree and viscosity,which led to a decrease in the migration ability between ions,and ultimately made the slag difficult to crystallize during the cooling.When the proportion of IS was higher than 60%,the addition of IS increased the CaO and FeO content in the system.As network modifiers,CaO and FeO could provide O^(2−)at a high temperature,which reacted with silicate network structure and continuously destroyed the complexity of network structure,thus reducing the polymerization degree and viscosity of slag.At this time,the migration ability between ions was enhanced,and needle-shaped/rod-shaped crystals were precipitated during the cooling process.Finally,the viscosity calculated by simulation and Einstein-Roscoe empirical formula demonstrated that the addition of IS could significantly improve the fluidity of coal ash and meet the requirements of the liquid slag-tapping gasifier.The purpose of this work was to provide theoretical support for slag flow mechanisms during the gasifier slagging-tapping process and the resource treatment of industrial solid waste.
基金funding provided through the Natural Sciences and Engineering Research Council of Canada(NSERC)Discovery grant and as the University of Prince Edward Island start up award to Yulin Hu.
文摘Potato is the fifth largest agricultural crop in Canada and contributes to the generation of an abundant amount of potato peel.However,disposal/recycling this peel remains a challenge due to the stringent environmental regulations.Consequently,there is a lack of an appropriate recycling and valorization methods of potato peel.Gasification is an effective technology for producing syngas and an ecofriendly waste disposal approach.Syngas is an important industrial intermediate to produce synthetic fuels and chemicals.To develop an ecofriendly and cost-effective valorization approach for potato peel,this study used a mixture of woody biomass(i.e.,wood chips)and potato peel to produce syngas by co-gasification using O_(2) as the gasifying agent at a constant equivalence ratio of 0.3 using Aspen Plus simulation software.The influences of gasification temperature and wood chip/potato peel weight ratio on the carbon conversion efficiency(CCE),and product gas composition(molar fraction)and lower heating value(LHV)of product gas were investigated.This simulation indicated that a positive synergistic interaction occurs between wood chips and potato peel in co-gasification process in terms of an increase in CCE by comparing the arithmetic value and real value at all simulated wood chip to potato peel weight ratios(44.9%to 85.8%,46.5%to 76.2%,and 48.1%to 78.6%at ratios of 25:75,50:50,and 75:25,respectively,for wood chips to potato peel).While the molar fraction of H_(2) and CO decreased continuously with increase in the weight percentage of wood chips in the wood chip-potato peel mixture from 0 wt%to 100 wt%(H_(2),at 42.1 mol%to 41.4 mol%;and CO at 44.0 mol%to 40.4 mol%),accompanied by a decrease of the LHV of the product gas(10.3 to 9.78 MJ·Nm^(−3)).The study concluded that co-gasification for producing syngas is feasible and environmental-friendly option to recycle and valorize potato peel.
基金financially supported by National Natural Science Foundation of China(No.22008236)。
文摘Some ash related problems,such as slagging at furnace bottom and fouling at the air pre-heater surface,are frequently encountered during circulating fluidized bed gasification(CFBG)of Zhundong coal.Low ash fusion temperatures(AFTs)and intense sodium release should be responsible for those problems.In industry,coal blending is deemed to be a feasible method to both improve AFTs and control sodium release.In this work,Wuhai coal was selected as blending coal.The ratio is varied from 0%to 40%by mass with 10%interval.The mixed samples were gasified by steam at 950°C in a lab-scale furnace.Some key indices,such as sodium release behaviors,ash slagging characteristics and char gasification performances,were investigated by ICP-OES,AFTs,XRD and TG analyzers,respectively.The results indicated that coal blending could significantly decrease sodium release behaviors.For ash slagging characteristics,it is surprised to find that three out of four AFTs(deformation temperature,softening temperature,hemispherical temperature)show an U-shaped correlation with blending ratio,indicating that a low ratio possibly causes more severe ash slagging problem.It is ascribed to the formation of substantial percentage of fusible Na-containing silicates and aluminosilicates.In addition,coal blending greatly increases ST-DT,implying that the ability of resistance to bed temperature fluctuation is markedly enhanced.Due to the high level of alkali and alkaline species,the synergistic effect is clearly observed during co-gasification.Taking all key indices into consideration,30%blending ratio of Wuhai coal is recommended.
基金supported by JST Grant Number JPMJPF2104 and Hirosaki University Fundthe scholarship from the Ministry of Education,Culture,Sport,Science and Technology(MEXT)of Japan.
文摘In this work,to efficiently utilize waste fruit and low-rank coal for the hydrogen(H_(2))-rich syngas production,steam co-gasification of banana peel(BP)and brown coal(BC)was studied in a fixed-bed reactor.The results showed that the gasification rate of BC was highly enhanced after mixing it with BP and the obvious synergistic effect was observed in all investigated three mixing weight ratios(i.e.,1:1,1:4,4:1),resulting in a higher carbon conversion as well as a H_(2)-rich gas production yield for the co-gasification.However,the extent of promotion by synergistic effect was affected by the reaction temperature,mixing ratio,and steam amount.It was found that the high potassium(K)species content in the BP provided the catalytic effect not only on water-gas shift reaction but also on tar reforming/cracking,thereby enhancing the gasification of BC.In addition,it is confirmed that steam should be an important factor to promote the synergistic effect and H_(2)-rich gas production.
基金The work was supported by the Outstanding Youth Science Foundation of Ningxia(2022AAC05016).
文摘Co-thermal chemical conversion of coal and biomass is one of the important ways to realize efficient and clean utilization of coal.In this study,a typical Ningdong coal-Yangchangwan bituminous coal and cow manure were used to study the synergistic effect of intrinsic alkali,alkaline earth metals(AAEM)and organic matter on the co-gasification of coal and biomass by thermogravimetry analyzer(TG).The results showed that AAEM had obvious synergistic promotion effect on the gasification of a bituminous coal-cow manure mixture in the isothermal gasification(1000℃),whereas the organic matter will show the opposite effect on the process.To further investigate the effect of organic matter on the gasification process,the influence of organic matter on non-isothermal(25-1000℃)gasification reaction was investigated with heating rate of 10℃/min,the kinetic parameters of the gasification reaction were obtained by Coats-Redfern method.The increase of biomass mass fraction in the sample facilitates the migration of alkali metals from the material to the solid phase.The possible mechanism of the synergistic effect of intrinsic AAEM/organic matter on the co-gasification process was proposed.
基金financially supported by the National International Cooperation Project(2017YFE0107600 and 2016YFE0202000)the Zhejiang Provincial Natural Science Foundation Project(LY17E060005).
文摘The co-gasification of sewage sludge and palm oil empty fruit bunch(EFB) in supercritical water(SCW) was conducted at 400 °C with a pressure of over 25 MPa. This study aimed to investigate the influence of EFB addition on the syngas production and its composition. The heavy metal distribution and the leaching potential of the solid residue were also assessed. The results showed that syngas yield significantly increased with the addition of EFB into the feedstock. The cold gas efficiency(CGE) and carbon efficiency(CE) of co-gasification were higher than those of individual gasification. The actual syngas production from co-gasification of sludge and EFB was 45% higher than the theoretical total volume. The results indicated that the addition of EFB to sludge had the synergetic promotion effect on syngas production from sludge and EFB in supercritical water. This enhancement might be due to the dissolution of alkali metals from EFB and the adjustment of organic ratio. In addition, higher percentage of heavy metals were deposited and stabilized in the solid residue after SCWG. The leaching concentration of heavy metals from the solid residues was decreased to a level below the standard limit which enables it to be safely disposed of in landfill. In conclusion, the EFB addition has been proved to promote syngas production,as well as, stabilize the heavy metal in solid residues during co-SCWG.
基金The authors gratefully express gratitude to all parties which have contributed towards the success of this project,both financially and technically,especially the S&T Innovation 2025 Major Special Programme(grant number 2018B10022)the Ningbo Natural Science Foundation Programme(grant number 2018A610069)+1 种基金funded by the Ningbo Science and Technology Bureau,China,as well as the Industrial Technology Innovation and Industrialization of Science and Technology Project,China(grant number 2014A35001-2)the UNNC FoSE Faculty Inspiration Grant,China.The Zhejiang Provincial Department of Science and Technology is also acknowledged for this research under its Provincial Key Laboratory Programme(2020E10018).
文摘This study investigates the potential of solid fuel blending as an effective approach to manipulate ash melting behaviour to alleviate ashrelated problems during gasification,thus improving design,operability and safety.The ash fusion characteristics of Qinghai bituminous coal together with Fushun,Xinghua and Laoheishan oil shales(and their respective blends)were quantified using a novel picture analysis and graphing method,which incorporates conventional ash fusion study,dilatometry and sintering strength test,in a CO/CO_(2)atmosphere.This imagebased characterisation method was used to monitor and quantify the complete melting behaviour of ash samples from room temperature to 1520℃.The impacts of blending on compositional changes during heating were determined experimentally via Xray diffraction and validated computationally using FactSage.Results showed that the melting point of Qinghai coal ash to be the lowest at 1116℃,but would increase up to 1208℃,1161℃and 1160℃with the addition of 30%50%of Laoheishan,Fushun,and Xinghua oil shales,respectively.The formation of highmelting anorthite and mullite structures inhibits the formation of lowmelting hercynite.However,the sintering point of Qinghai coal ash was seen to decrease from 1005℃to 855℃,834℃,and 819℃in the same blends due to the formation of lowmelting aluminosilicate.Results also showed that blending directly influences the sintering strength during the various stages of melting.The key finding from this study is that it is possible to mitigate against the severe ash slagging and fouling issue arising from high calcium and iron coals by cogasification with a high silicaalumina oil shale.Moreover,blending coals with oil shales can also modify the ash melting behaviour of fuels to create the optimal ash chemistry that meets the design specification of the gasifier,without adversely affecting thermal performance.
文摘This paper describes a single fluidized bed by the two-step gasification of the working method, process and biomass and coal co-gasification by a certain proportion of the results of a typical run. The results show that the biomass gasifi-cation technology for raw materials has a wide adaptability, the tar content in the gas is less than 10mg/m3,component in it ,the H2+CO>70%, H2/C ≈1~2,especially suitable for biomass from hydrogen, synthetic alcohol fuel, is a promising approach.
