Chemical-looping gasification of biomass in a 10 kW_(th) interconnected fluidized bed reactor using Fe_2O_3/Al_2O_3 oxygen carrier

Abstract:The aim of this research is to design and operate a 10 kW hot chemical-looping gasification(CLG)unit using Fe2O3/Al2O3as an oxygen carrier and saw dust as a fuel.The effect of the operation temperature on gas composition in the air reactor and the fuel reactor,and the carbon conversion of biomass to CO2and CO in the fuel reactor have been experimentally studied.A total60 h run has been obtained with the same batch of oxygen carrier of iron oxide supported with alumina.The results show that CO and H2concentrations are increased with increasing temperature in the fuel reactor.It is also found that with increasing fuel reactor temperature,both the amount of residual char in the fuel reactor and CO2concentration of the exit gas from the air reactor are degreased.Carbon conversion rate and gasification efficiency are increased by increasing temperature and H2production at 870℃reaches the highest rate.Scanning electron microscopy(SEM),X-ray diffraction(XRD)and BET-surface area tests have been used to characterize fresh and reacted oxygen carrier particles.The results display that the oxygen carrier activity is not declined and the specific surface area of the oxygen carrier particles is not decreased significantly.

Thermodynamic Analysis and Synthesis Gas Generation by Chemical-Looping Gasification of Biomass with Nature Hematite as Oxygen Carriers

Thermodynamic parameters of chemical reactions in the system were carried out through thermodynamic analysis. According to the Gibbs free energy minimization principle of the system, equilibrium composition of the reactions of chemical-looping gasification (CLG) of biomass with natural hematite (Fe2O3) as oxygen carrier were analyzed using commercial software of HSC Chemistry 5.1. The feasibility of the CLG of biomass with hematite was experimental verified in a lab-scale bubbling fluidized bed reactor using argon as fluidizing gas. It was indicated the experimental results were consistent with the theoretical analysis. The presence of oxygen carrier gave a significant effect on the biomass conversion and improved the synthesis gas yield obviously. It was observed that the gas content of CO and H2 was over 70% in CLG of biomass. The reduced hematite particles mainly existed in form of FeO. It was showed that the reduction of natural hematite with biomass proceeds in a stepwise manner from Fe2O3 →Fe3O4→ FeO. Reduction product of natural hematite can be restored the lattice oxygen by oxidation with air.

Structural properties of residual carbon in coal gasification fine slag and their influence on flotation separation and resource utilization:A review

Coal gasification fine slag(FS)is a typical solid waste generated in coal gasification.Its current disposal methods of stockpil-ing and landfilling have caused serious soil and ecological hazards.Separation recovery and the high-value utilization of residual carbon(RC)in FS are the keys to realizing the win-win situation of the coal chemical industry in terms of economic and environmental benefits.The structural properties,such as pore,surface functional group,and microcrystalline structures,of RC in FS(FS-RC)not only affect the flotation recovery efficiency of FS-RC but also form the basis for the high-value utilization of FS-RC.In this paper,the characteristics of FS-RC in terms of pore structure,surface functional groups,and microcrystalline structure are sorted out in accordance with gasification type and FS particle size.The reasons for the formation of the special structural properties of FS-RC are analyzed,and their influence on the flotation separation and high-value utilization of FS-RC is summarized.Separation methods based on the pore structural characterist-ics of FS-RC,such as ultrasonic pretreatment-pore-blocking flotation and pore breaking-flocculation flotation,are proposed to be the key development technologies for improving FS-RC recovery in the future.The design of low-cost,low-dose collectors containing polar bonds based on the surface and microcrystalline structures of FS-RC is proposed to be an important breakthrough point for strengthening the flotation efficiency of FS-RC in the future.The high-value utilization of FS should be based on the physicochemical structural proper-ties of FS-RC and should focus on the environmental impact of hazardous elements and the recyclability of chemical waste liquid to es-tablish an environmentally friendly utilization method.This review is of great theoretical importance for the comprehensive understand-ing of the unique structural properties of FS-RC,the breakthrough of the technological bottleneck in the efficient flotation separation of FS,and the expansion of the field of the high value-added utilization of FS-RC.

Agglomeration of coal and polyethylene mixtures during fixed‑bed co‑gasification

The article presents the results of experimental studies on the gasification of mixtures of brown coal and polyethylene(up to 20 wt%fraction)in a laboratory reactor.The work aims to study the agglomeration process during the heating and oxidation of the mixtures.The measurement results(gas composition,pressure drop)provide indirect information on the dynamics of thermal decomposition and structural changes in the fuel bed.We have shown that the interaction between polyethylene and a coal surface leads to the formation of dense agglomerates,in which the molten polymer acts as a binder.Clinkers form as a result of interfacial interactions between components and filtration flow rearranging.The hydrogen/carbon ratio in the solid residue of coal-polyethylene co-gasification increases from 0.07–0.2 to 1.11,indicating the formation of stable hydrocarbon compounds on the carbon surface.The conducted research makes it possible to identify possible interactions between chemical reactions and transfer processes that lead to agglomeration in mixtures of coal with polyethylene.

Upcycling municipal solid waste to sustainable hydrogen via two-stage gasification-reforming

As global municipal solid waste(MSW)quantities continue to escalate,serious socio-environmental challenges arise,necessitating innovative solutions.Waste-to-hydrogen(WTH)via two-stage gasification-reforming(TSGR)presents an emergent technology for MSW upcycling,offering to ease waste management burdens and bolster the burgeoning hydrogen economy.Despite early initiatives to advance TSGR technology,a cohesive and critical analysis of cutting-edge knowledge and strategies to enhance hydrogen production remains lacking.This review aggregates literature on MSW upcycling to hydrogen via TSGR,with a focus on optimizing process control and catalytic efficiency.It underscores technological avenues to augment hydrogen output,curtail catalyst costs,and refine system performance.Particularly,the review illuminates the potential for integrating chemical and calcium looping into TSGR processes,identifying opportunities,and pinpointing challenges.The review concludes with a summary of the current state of techno-economic analysis for this technology,presenting outstanding challenges and future research directions,with the ultimate goal of transitioning WTH from theoretical to practical application.

Multiscale analysis of fine slag from pulverized coal gasification in entrained-flow bed

Fine slag(FS)is an unavoidable by-product of coal gasification.FS,which is a simple heap of solid waste left in the open air,easily causes environmental pollution and has a low resource utilization rate,thereby restricting the development of energy-saving coal gasification technologies.The multiscale analysis of FS performed in this study indicates typical grain size distribution,composition,crystalline structure,and chemical bonding characteristics.The FS primarily contained inorganic and carbon components(dry bases)and exhibited a"three-peak distribution"of the grain size and regular spheroidal as well as irregular shapes.The irregular particles were mainly adsorbed onto the structure and had a dense distribution and multiple pores and folds.The carbon constituents were primarily amorphous in structure,with a certain degree of order and active sites.C 1s XPS spectrum indicated the presence of C–C and C–H bonds and numerous aromatic structures.The inorganic components,constituting 90%of the total sample,were primarily silicon,aluminum,iron,and calcium.The inorganic components contained Si–O-Si,Si–O–Al,Si–O,SO_(4)^(2−),and Fe–O bonds.Fe 2p XPS spectrum could be deconvoluted into Fe 2p_(1/2) and Fe 2p_(3/2) peaks and satellite peaks,while Fe existed mainly in the form of Fe(III).The findings of this study will be beneficial in resource utilization and formation mechanism of fine slag in future.

A critical review on direct catalytic hydrogasification of coal into CH_(4):catalysis process configurations,evaluations,and prospects

Coal catalytic hydrogasification(CCHG)is a straightforward approach for producing CH_(4),which shows advantages over the mature coal-to-CH_(4) technologies from the perspectives of CH_(4) yield,thermal efficiency,and CO_(2) emission.The core of CCHG is to make carbon in coal convert into CH_(4) efficiently with a catalyst.In the past decades,intensive research has been devoted to catalytic hydrogasification of model carbon(pitch coke,activated carbon,coal char).However,the chemical process of CCHG is still not well understood because the coal structure is more complicated,and CCHG is a combination of coal catalytic hydropyrolysis and coal char catalytic hydrogasification.This review seeks to shed light on the catalytic process of raw coal during CCHG.The configuration of suitable catalysts,operating conditions,and feedstocks for tailoring CH_(4) formation were identified,and the underlying mechanisms were elucidated.Based on these results,the CCHG process was evaluated,emphasizing pollutant emissions,energy efficiency,and reactor design.Furthermore,the opportunities and strategic approaches for CCHG under the restraint of carbon neutrality were highlighted by considering the penetration of“green”H2,biomass,and CO_(2) into CCHG.Preliminary investigations from our laboratories demonstrated that the integrated CCHG and biomass/CO_(2) hydrogenation process could perform as an emerging pathway for boosting CH_(4) production by consuming fewer fossil fuels,fulfilling the context of green manufacturing.This work not only provides systematic knowledge of CCHG but also helps to guide the efficient hydrogenation of other carbonaceous resources such as biomass,CO_(2),and coal-derived wastes.

A Gasification Technology to Combine Oil Sludge with Coal-Water Slurry:CFD Analysis and Performance Determination

The development of more environment-friendly ways to dispose of oil sludge is currently regarded as a hot topic.In this context,gasification technologies are generally seen as a promising way to combine oil sludge with coal–water slurry(CWS)and generate resourceful fuel.In this study,a novel five-nozzle gasifier reactor was analyzed by means of a CFD(Computational fluid dynamic)method.Among several influential factors,special attention was paid to the height-to-diameter ratio of the gasifier and the mixing ratio of oil sludge,which are known to have a significant impact on the flow field,temperature distribution and gasifier performances.According to the numerical results,the optimal height-to-diameter ratio and oil mixing ratio are about 2.4:1 and 20%,respectively.Furthermore,the carbon conversion rate can become as high as 98.55%with the hydrolysis rate reaching a value of 53.88%.The consumption of raw coal and oxygen is generally reduced,while the effective gas production is increased to 50.93 mol/%.

Effective separation of coal gasification fine slag: Role of classification and ultrasonication in enhancing flotation

Effective separation of residual carbon and ash is the basis for the resource utilization of coal gasification fine slag(CGFS).The conventional flotation process of CGFS has the bottlenecks of low carbon recovery and high collector dosage.In order to address these issues,CGFS sample taken from Shaanxi,China was used as the study object in this paper.A new process of size classification-fine grain ultrasonic pretreatment flotation(SC-FGUF)was proposed and its separation effect was compared with that of wholegrain flotation(WGF)as well as size classification-fine grain flotation(SC-FGF).The mechanism of its enhanced separation effect was revealed through flotation kinetic fitting,flotation flow foam layer stability,particle size composition,surface morphology,pore structure,and surface chemical property analysis.The results showed that compared with WGF,pre-classification could reduce the collector dosage by 84.09%and the combination of pre-classification and ultrasonic pretreatment could increase the combustible recovery by 17.29%and up to 93.46%.The SC-FGUF process allows the ineffective adsorption of coarse residual carbon to collector during flotation stage to be reduced by pre-classification,and the tightly embedded state of fine CGFS particles is disrupted and surface oxidizing functional group occupancy was reduced by ultrasonic pretreatment,thus carbon and ash is easier to be separated in the flotation process.In addition,some of the residual carbon particles were broken down to smaller sizes in the ultrasonic pretreatment,which led to an increase in the stability of flotation flow foam layer and a decrease in the probability of detachment of residual carbon particles from the bubbles.Therefore,SCFGUF could increase the residual carbon recovery and reduce the flotation collector dosage,which is an innovative method for carbon-ash separation of CGFS with good application prospect.

Experimental study on the activation of coal gasification fly ash from industrial CFB gasifiers

Coal gasification fly ash(CGFA)is an industrial solid waste from the coal circulating fluidized bed(CFB)gasification process,and it needs to be effectively disposed to achieve sustainable development of the environment.To realize the application of CGFA as a precursor of porous carbon materials,the physicochemical properties of three kinds of CGFA from industrial CFB gasifiers are analyzed.Then,the activation potential of CGFA is acquired via steam activation experiments in a tube furnace reactor.Finally,the fluidization activation technology of CGFA is practiced in a bench-scale CFB test rig,and its advantages are highlighted.The results show that CGFA is characterized by a high carbon content in the range of 54.06%–74.09%,an ultrafine particle size(d50:16.3–26.1 μm),and a relatively developed pore structure(specific surface area SSA:139.29–551.97 m^(2)·g^(-1)).The proportion of micropores in CGFA increases gradually with the coal rank.Steam activation experiments show that the pore development of CGFA mainly includes three stages:initial pore development,dynamic equilibrium between micropores and mesopores and pore collapse.The SSA of lignite fly ash(LFA),subbituminous fly ash(SBFA)and anthracite fly ash(AFA)is maximally increased by 105%,13%and 72%after steam activation;the order of the largest carbon reaction rate and decomposition ratio of steam among the three kinds of CGFA is SBFA>LFA>AFA.As the ratio of oxygen to carbon during the fluidization activation of LFA is from 0.09 to 0.19,the carbon conversion ratio increases from 14.4%to 26.8%and the cold gas efficiency increases from 6.8%to 10.2%.The SSA of LFA increases by up to 53.9%during the fluidization activation process,which is mainly due to the mesoporous development.Relative to steam activation in a tube furnace reactor,fluidization activation takes an extremely short time(seconds)to achieve the same activation effect.It is expected to further improve the activation effect of LFA by regulating the carbon conversion ratio range of 27%–35%to create pores in the initial development stage.

Ca_(2)MnO_(4)-layered perovskite modified by NaNO_(3)for chemical-looping oxidative dehydrogenation of ethane to ethylene

Chemical-looping oxidative dehydrogenation(CL-ODH)is a process designed for the conversion of alkanes into olefins through cyclic redox reactions,eliminating the need for gaseous O_(2).In this work,we investigated the use of Ca_(2)MnO_(4)-layered perovskites modified with NaNO_(3) dopants,serving as redox catalysts(also known as oxygen carriers),for the CL-ODH of ethane within a temperature range of 700-780℃.Our findings revealed that the incorporation of NaNO_(3) as a modifier significantly-nhanced the selectivity for-thylene generation from Ca_(2)MnO_(4).At 750℃and a gas hourly space velocity of 1300 h^(-1),we achieved an-thane conversion up to 68.17%,accompanied by a corresponding-thylene yield of 57.39%.X-ray photoelectron spectroscopy analysis unveiled that the doping NaNO_(3) onto Ca_(2)MnO_(4) not only played a role in reducing the oxidation state of Mn ions but also increased the lattice oxygen content of the redox catalyst.Furthermore,formation of NaNO_(3) shell on the surface of Ca_(2)MnO_(4) led to a reduction in the concentration of manganese sites and modulated the oxygen-releasing behavior in a step-wise manner.This modulation contributed significantly to the enhanced selectivity for ethylene of the NaNO_(3)-doped Ca_(2)MnO_(4) catalyst.These findings provide compelling evidence for the potential of Ca_(2)MnO_(4)-layered perovskites as promising redox catalysts in the context of CL-ODH reactions.

Advancements in biomass gasification research utilizing iron-based oxygen carriers in chemical looping:A review

Biomass,recognized as renewable green coal,is pivotal for energy conservation,emission reduction,and dualcarbon objectives.Chemical looping gasification,an innovative technology,aims to enhance biomass utilization efficiency.Using metal oxides as oxygen carriers regulates the oxygen-to-fuel ratio to optimize synthesis product yields.This review examines various oxygen carriers and their roles in chemical looping biomass gasification,including natural iron ore types,industrial by-products,cerium oxide-based carriers,and core-shell structures.The catalytic,kinetic,and phase transfer properties of iron-based oxygen carriers are analyzed,and their catalytic cracking capabilities are explored.Molecular interactions are elucidated and system performance is optimized by providing insights into chemical looping reaction mechanisms and strategies to improve carrier efficiency,along with discussing advanced techniques such as density functional theory(DFT)and reactive force field(ReaxFF)molecular dynamics(MD).This paper serves as a roadmap for advancing chemical looping gasification towards sustainable energy goals.

Mechanism of K/Ni Etching for Biochar-H_(2)O Gasification

Biomass-H_(2)O gasification is a complex thermochemical reaction,including three processes of volatile removal:homogeneous/heterogeneous reforming,biochar gasification and etching.The rate-determining step is biochar-H_(2)O gasification and etching so the DFT is carried out to see the catalytic role of different metal elements(K/Ni)in the zigzag biochar model.The calculation results show that the gasification of biochar-H_(2)O needs to go through four processes:dissociative adsorption of water,hydrogen transfer(hydrogen desorption,hydrogen atom transfer),carbon dissolution and CO desorption.The energy barrier indicated that the most significant step in reducing the activation energy of K is reflected in the hydrogen transfer step,which is reduced from 374.14 kJ/mol to 152.41 kJ/mol;the catalytic effect of Ni is mainly reflected in the carbon dissolution step,which is reduced from 122.34 kJ/mol to 84.8 kJ/mol.The existence of K causes the edge to have a stronger attraction to H and does not destroy theπbonds of biochar molecules.The destruction ofπbonds is mainly due to the role of H free radicals,while the destruction ofπbonds will lead to easier C-C bond rupture.Ni shows a strong attraction to O in OH,which forms strong Ni-O chemical bonds.Ni can also destroy the aromatic structure directly,making the gasification easier to happen.This study explored the catalytic mechanism of K/Ni on the biochar-H_(2)O gasification at the molecular level and looked forward to the potential synergy of K/Ni,laying a foundation for experimental research and catalyst design.

Occurrence,leaching behavior,and detoxification of heavy metal Cr in coal gasification slag

Coal gasification slag(CGS)is a type of solid waste produced during coal gasification,in which heavy metals severely restrict its resource utilization.In this work,the mineral occurrence and distribution of typical heavy metal Cr in CGS is investigated.The leaching behavior of Cr under different conditions is studied in detail.Acid leaching-selective oxidation-coprecipitation method is proposed based on the characteristics of Cr in CGS.The detoxification of Cr in CGS is realized,and the detoxification mechanism is clarified.Results show that Cr is highly enriched in CGS.The speciation of Cr is mainly residual fraction(74.47%-86.12%),which is combined with amorphous aluminosilicate.Cr^(3+)and Cr^(6+)account for 90.93%-94.82%and 5.18%-9.07%of total Cr,respectively.High acid concentration and high liquid-solid ratio are beneficial to destroy the lattice structure of amorphous aluminosilicate,thus improving the leaching efficiency of Cr,which can reach 97.93%under the optimal conditions.Acid leaching-selective oxidation-coprecipitation method can realize the detoxification of Cr in CGS.Under the optimal conditions,the removal rates of Fe^(3+)and Cr^(3+)in the leaching solution are 80.99%-84.79%and 70.58%-71.69%,respectively,while the loss rate of Al^(3+)is only 1.10%-3.35%.Detoxification slag exists in the form of Fe-Cr coprecipitation(Fe_(1-x)Cr_xOOH),which can be used for smelting.The detoxification acid leaching solution can be used to prepare inorganic polymer composite coagulant poly-aluminum chloride(PAC).This study can provide theoretical and data guidance for detoxification of heavy metal Cr in CGS and achieve resource utilization of coal gasification solid waste.

Recycling and utilization of coal gasification residues for fabricating Fe/C composites as novel microwave absorbents

Under the background of a transformation of the global energy structure,coal gasification technology has a wide application prospect,but its by-product,the coal gasification residue(CGR),is still not being efficiently utilized for recycling.The CGR contains abundant carbon components,which could be applied to the microwave absorption field as the carbon matrix.In this study,Fe/CGR composites are fabricated via a two-step method,including the impregnation of Fe^(3+)and the reduction process.The influence of the different loading capacities of the Fe component on the morphology and electromagnetic properties is studied.Moreover,the loading content of Fe and the surface morphology of the Fe/CGR can be reasonably controlled by adjusting the concentration of the ferric nitrate solution.Meanwhile,Fe particles are evenly inserted on the CGR framework,which expands the Fe/CGR interfaces to enhance interfacial polarization,thus further improving the microwave-absorbing(MA)properties of composites.Particularly,as the Fe^(3+)concentration is 1.0 mol/L,the Fe/CGR composite exhibits outstanding performance.The reflection loss reaches-39.3 dB at 2.5 mm,and the absorption bandwidth covers 4.1 GHz at 1.5 mm.In this study,facile processability,resource recycling,appropriately matched impedance,and excellent MA performance are achieved.Finally,the Fe/CGR composites not only enhance the recycling of the CGR but also pioneer a new path for the synthesis of excellent absorbents.

Gasification kinetic studies of low volatile weakly caking coal

Present investigation focuses on the fractional conversion of low volatile weakly caking coal(LVWC)under the standard set of operating conditions for gasification.For this purpose,samples of LVWC of different ash content have been collected from Kusunda Area of Bharat Coking Coal Ltd.Gasification results were validated using Homogenous and Shrinking Core kinetic models and the suitability of selected samples for gasification was assessed by estimating the activation energy.The values of activation energy for LVWC samples were obtained in the range of 25.17-44.09 kJ/mol.Further,empirical models were developed to correlate the response of interest with the input variables(temperature,residence time and CO_(2) flow rate).The significance of these developed empirical models was checked using analysis of variance(ANOVA).

Microscopic mechanism study and process optimization of dimethyl carbonate production coupled biomass chemical looping gasification system

Biomass chemical looping gasification technology is one of the essential ways to utilize abundant biomass resources.At the same time,dimethyl carbonate can replace phosgene as an environmentfriendly organic material for the synthesis of polycarbonate.In this paper,a novel system coupling biomass chemical looping gasification with dimethyl carbonate synthesis with methanol as an intermediate is designed through microscopic mechanism analysis and process optimization.Firstly,reactive force field molecular dynamics simulation is performed to explore the reaction mechanism of biomass chemical looping gasification to determine the optimal gasification temperature range.Secondly,steady-state simulations of the process based on molecular dynamics simulation results are carried out to investigate the effects of temperature,steam to biomass ratio,and oxygen carrier to biomass ratio on the syngas yield and compositions.In addition,the main energy indicators of biomass chemical looping gasification process including lower heating value and cold gas efficiency are analyzed based on the above optimum parameters.Then,two synthesis stages are simulated and optimized with the following results obtained:the optimal temperature and pressure of methanol synthesis stage are 150℃ and 4 MPa;the optimal temperature and pressure of dimethyl carbonate synthesis stage are 140℃ and 0.3 MPa.Finally,the pre-separation-extraction-decantation process separates the mixture of dimethyl carbonate and methanol generated in the synthesis stage with 99.11%purity of dimethyl carbonate.Above results verify the feasibility of producing dimethyl carbonate from the perspective of multi-scale simulation and realize the multi-level utilization of biomass resources.

Integrated vacuum pressure swing adsorption and Rectisol process for CO_(2) capture from underground coal gasification syngas

An integrated vacuum pressure swing adsorption(VPSA) and Rectisol process is proposed for CO_(2) capture from underground coal gasification(UCG) syngas. A ten-bed VPSA process with silica gel adsorbent is firstly designed to pre-separate and capture 74.57% CO_(2) with a CO_(2) purity of 98.35% from UCG syngas(CH_(4)/CO/CO_(2)/H_(2)/N_(2)= 30.77%/6.15%/44.10%/18.46%/0.52%, mole fraction, from Shaar Lake Mine Field,Xinjiang Province, China) with a feed pressure of 3.5 MPa. Subsequently, the Rectisol process is constructed to furtherly remove and capture the residual CO_(2)remained in light product gas from the VPSA process using cryogenic methanol(233.15 K, 100%(mass)) as absorbent. A final purified gas with CO_(2) concentration lower than 3% and a regenerated CO_(2) product with CO_(2) purity higher than 95% were achieved by using the Rectisol process. Comparisons indicate that the energy consumption is deceased from 2.143 MJ·kg^(-1) of the single Rectisol process to 1.008 MJ·kg^(-1) of the integrated VPSA & Rectisol process, which demonstrated that the deployed VPSA was an energy conservation process for CO_(2) capture from UCG syngas. Additionally, the high-value gas(e.g., CH_(4)) loss can be decreased and the effects of key operating parameters on the process performances were detailed.

Effects of Different Calcining Temperatures on the Properties of Ceramsite Prepared by High-carbon Gasification Slag

The structure and characteristics of high-performance lightweight aggregates produced by high-carbon gasification slag were investigated by X-ray diffraction,scanning electron microscopy,thermogravimetry/differential thermogravimetr,differential scanning calorimetry-Fourier transform infrared,and mercury intrusion porosimetry,respectively.The experimental results show that the ceramsite undergoes two weightless stages in the calcining process.With the increase in the calcining temperature,a large number of pores are formed inside the ceramsite,its structure becomes denser,but the calcining temperature band of the ceramsite becomes narrow.The crystalline phase of the ceramsite changes at different calcining temperatures and the mineral phase changes from the earlieralbite,quartz,oligoclase,hematite,etc,to a silica-aluminum-rich glass phase.The 1130℃ is a more suitable calcining temperature,and the cylinder compressive strength of ceramics is 11.59 MPa,the packing density,apparent density,porosity,and water absorption are 939.11 kg/m^(3),1643.75 kg/m^(3),28.11%,and 10.35%,respectively,which can meet the standards for high-strength lightweight aggregates.

Gasification of Organic Waste:Parameters,Mechanism and Prediction with the Machine Learning Approach

Gasification of organic waste represents one of the most effective valorization pathways for renewable energy and resources recovery,while this process can be affected by multi-factors like temperature,feedstock,and steam content,making the product’s prediction problematic.With the popularization and promotion of artificial intelligence such as machine learning(ML),traditional artificial neural networks have been paid more attention by researchers from the data science field,which provides scientific and engineering communities with flexible and rapid prediction frameworks in the field of organic waste gasification.In this work,critical parameters including temperature,steam ratio,and feedstock during gasification of organic waste were reviewed in three scenarios including steam gasification,air gasification,and oxygen-riched gasification,and the product distribution and involved mechanism were elaborated.Moreover,we presented the details of ML methods like regression analysis,artificial neural networks,decision trees,and related methods,which are expected to revolutionize data analysis and modeling of the gasification of organic waste.Typical outputs including the syngas yield,composition,and HHVs were discussed with a better understanding of the gasification process and ML application.This review focused on the combination of gasification and ML,and it is of immediate significance for the resource and energy utilization of organic waste.