Hydrogen-enriched ironmaking presents a promising approach to mitigate coke consumption and carbon emission in blast furnace(BF)operations.This work investigated the relationship between the structural features of cok...Hydrogen-enriched ironmaking presents a promising approach to mitigate coke consumption and carbon emission in blast furnace(BF)operations.This work investigated the relationship between the structural features of cokes and their reactivity towards solution loss(SL),especially under hydrogen-enriched atmospheres.Six cokes were characterized,and their SL behaviors were examined under varying atmospheres to elucidate the effects of hydrogen enrichment.The results indicate that an increase in fixed carbon content leads to a decrease in the coke reactivity index(CRI)and an increase in coke strength after reaction(CSR),in the CO_(2) atmosphere,the CSR of coke increases from 35.76%−62.83%,while in the 90CO_(2)/10H_(2) atmosphere,the CSR of coke increases from 65.67%−84.09%.There is a good linear relationship between CRI and microcrystalline structure parameters of coke.Cokes with larger crystalline size,lower amorphous content,and smaller optical texture index(OTI)values show enhanced resistance to degradation and maintain structural integrity in BF.Kinetic analysis performed with the shifted-modified-random pore model(S-MRPM)reveals that alterations in pore structure and intrinsic mineral composition significantly influence the reaction rate.The introduction of a small amount of water vapor raises SL rates,whereas a minor addition of hydrogen(<10%)decelerates SL due to its incomplete conversion to water vapor and the reduced partial pressure of the gasifying agent.Thermodynamic calculations also indicate that the introduced hydrogen does not convert into the same fraction of water vapor.The shift from chemical reaction control to gas diffusion control as the rate-determining step with rising temperatures during SL process was confirmed,and the introduction of hydrogen does not notably alter SL behavior.This result demonstrated that introducing a small amount of hydrogen(<10%)can mitigate SL rates,thereby enhancing coke strength and reducing coke consumption and carbon emissions.展开更多
Shot cokes are frequently formed in the delayed coking unit treating the super viscous oil at PetroChina＇s Liaohe Petrochemical Company. Considerable work has been carded out to avoid the formation of shot cokes. The...Shot cokes are frequently formed in the delayed coking unit treating the super viscous oil at PetroChina＇s Liaohe Petrochemical Company. Considerable work has been carded out to avoid the formation of shot cokes. The test results obtained have shown that the property of super viscous oil has played a key role in the formation of shot cokes. After adjusting and optimizing the process indices the operating regime of the delayed coking unit at a throughput of 118t/h of the super viscous oil is specified as follows： a reaction temperature of 498-502℃, a reaction pressure of 0.17-0.25 MPa, a recycle ratio of 0.5-0.6 and a fractionation tower bottom temperature of 355-365 ℃. In the meantime, the delayed coking process has adopted measures to enhance pre-fractionation of the feedstock to rationally remove light fractions and maintain a steady gas velocity in order to avoid the formation of shot cokes.展开更多
In order to effectively utilize the high reactivity coke, the gasification characteristics of high and low reactivity cokes were investigated at 1100 ℃. Low reactivity coke A and high reactivity coke B were chosen an...In order to effectively utilize the high reactivity coke, the gasification characteristics of high and low reactivity cokes were investigated at 1100 ℃. Low reactivity coke A and high reactivity coke B were chosen and charged into the reaction tube in two methods. The results indicated that the mass loss ratio of high reactivity coke in mixed cokes was more significant than that of single high reactivity coke in the middle stage of reaction. Nevertheless, the mass loss ratio of low reactivity coke in mixed cokes was less than that of single low reactivity coke. It was mainly attributed to gas diffusion and internal reaction of coke. When high and low reactivity cokes were mixed, the practical average mass loss ratio was nearly the same as the weighted average. The microscopic structures of coke indicated that with the increase of reaction time, the external and internal layers of low reactivity coke reacted more uniformly with CO2, whereas the reaction degree of external layer of high reactivity coke was obviously higher.展开更多
It is difficult to distinguish tamping coke and top charging coke by conventional testing methods, such as cold strength, abrasion resistance, reactivity and strength after reaction. Some of tamping coket s properties...It is difficult to distinguish tamping coke and top charging coke by conventional testing methods, such as cold strength, abrasion resistance, reactivity and strength after reaction. Some of tamping coket s properties were even bet-ter than those of top charging coke, hut from practical using effects of blast furnace, tamping coke was not as good as top charging coke. The reaction conditions were featured as high temperature, high alkali condition, intense reac-tion atmosphere and short time. Distribution of porosity in profile, microstructure and slag forming property of ash were analyzed and following conclusions were obtained. After alkali-rich reaction, there were obvious differences be- tween top charging coke and tamping coke in microstructure, The porosityts unevenness of tamping coke was greater than those of top charging coke, and tamping coke was with less and big pores in out space and inner part was dense with more throughout pores. After phase diagram and microstructure analysis, it could he obtained that ash forming characteristics of top charging coke were better than those of tamping coke, and top charging coke＇ s pores were blocked more seriously than those of tamping coke. From analysis of tuyere samples, it could be found that calcium content of ash in coke＇s pores was small and it should belong to coke＇s inherent ash; kalium （wκ =28%） was unusu-ally high in coke. so the situation of high alkali was close to real blast furnace reaction condition.展开更多
A needle coke was graphitized at different heat treatment temperature (2 000℃ to 3 000℃). The electrochemical intercalation mechanism of Li into the graphitized coke has been studied in Li|1 mol·L 1 LiClO 4+eth...A needle coke was graphitized at different heat treatment temperature (2 000℃ to 3 000℃). The electrochemical intercalation mechanism of Li into the graphitized coke has been studied in Li|1 mol·L 1 LiClO 4+ethylene carbonate/diethylene carbonate|graphite cells, using an in situ X Ray diffraction (XRD) technique.The study of Li C intercalation processes of the graphitized coke reveals that there are three major types of intercalation behavior.The first is uniformly intercalated at all Li C compounds in graphitized coke heated at 2 250℃;the second is obviously staging phenomenon during intercalation for the graphitized coke heated at 2 750℃; the third is cointercalation of solvated Li ion at high potential (>0.3V) and then lithium electrochemical intercalation at lower potential for that heated at 3 000℃, resulting in the decrease of capacity and efficiency of graphite negative electrode for lithium ion secondary battery.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
Coking industry is a potential source of heavy metals(HMs)pollution.However,its impacts to the groundwater of surrounding residential areas have not been well understood.This study investigated the pollution character...Coking industry is a potential source of heavy metals(HMs)pollution.However,its impacts to the groundwater of surrounding residential areas have not been well understood.This study investigated the pollution characteristics and health risks of HMs in groundwater nearby a typical coking plant.Nine HMs including Fe,Zn,Mo,As,Cu,Ni,Cr,Pb and Cd were analyzed.The average concentration of total HMswas higher in the nearby area(244.27μg/L)than that of remote area away the coking plant(89.15μg/L).The spatial distribution of pollution indices including heavy metal pollution index(HPI),Nemerow index(NI)and contamination degree(CD),all demonstrated higher values at the nearby residential areas,suggesting coking activity could significantly impact the HMs distribution characteristics.Four sources of HMs were identified by Positive Matrix Factorization(PMF)model,which indicated coal washing and coking emission were the dominant sources,accounted for 40.4%,and 31.0%,respectively.Oral ingestionwas found to be the dominant exposure pathway with higher exposure dose to children than adults.Hazard quotient(HQ)values were below 1.0,suggesting negligible non-carcinogenic health risks,while potential carcinogenic risks were from Pb and Ni with cancer risk(CR)values>10−6.Monte Carlo simulation matched well with the calculated results with HMs concentrations to be the most sensitive parameters.This study provides insights into understanding how the industrial coking activities can impact the HMs pollution characteristics in groundwater,thus facilitating the implement of HMs regulation in coking industries.展开更多
This work proposed a strategy to improve the caking index of polyethylene terephthalate(PET)waste,in which low-temperature pyrolysis treatment(LTPT)was used to depolymerize PET waste.The mechanism of G modification wa...This work proposed a strategy to improve the caking index of polyethylene terephthalate(PET)waste,in which low-temperature pyrolysis treatment(LTPT)was used to depolymerize PET waste.The mechanism of G modification was revealed combining thermogravimetric(TG)analysis,Fourier transform infrared spectroscopy,pyrolysis-gas chromatography with mass spectrometric detection,and solid-state 13C nuclear magnetic resonance spectroscopy.Furthermore,crucible coking experiments were also conducted using industrial coal mixture and treated PET with the optimum G(PET300)or raw PET to evaluate the applicability of PET waste in coal-blending coking.According to characterization results of coke reactivity(CR),coke strength after reaction(CSR)indices,TG-related curves,pore volumes,and Raman spectra of the resultant cokes,LTPT could greatly increase the G of PET,and the optimum temperature was 300℃.Specifically,compared with the coke obtained from the blend with PET,the CR of the coke produced from the blend with PET300 decreased by 4.9%,whereas the CSR of the increased by 7.4%,suggesting that LTPT could increase the proportion of PET used for coal-blending coking.The improvement in G is attributed to the changes in C-O/C=O ratio,aliphatic H and aromaticity caused by LTPT.展开更多
Pursuing green,low-carbon ironmaking technology primarily aims to reduce fuel ratios,especially coke ratios.Simultaneously,the reduction in coke ratios causes the coke layer in the blast furnace(BF)to become thinner,d...Pursuing green,low-carbon ironmaking technology primarily aims to reduce fuel ratios,especially coke ratios.Simultaneously,the reduction in coke ratios causes the coke layer in the blast furnace(BF)to become thinner,deteriorating the gas and liquid permeability of the burden column.This exacerbates coke degradation,significantly impacting the smelting process and increasing the demand for high-quality coke.To investigate the existence state of coke in the hearth,a 2500 m3 BF in China was taken as the research object,and three sets of samples at different heights of the hearth were obtained during planned outage.The results indicate that coke undergoes a significant degradation upon reaching the hearth.The proportion of coke particles smaller than 50 mm ranges from 81.22%to 89.50%.The proportion of coke particles larger than 20 mm decreases as the distance from the centerline of the tuyere increases,while the proportion of particles smaller than 10 mm increases with this distance.Additionally,the closer the bottom of the furnace is,the smaller the coke particle size becomes.The composition of slag filling the coke pores is similar to that of the final slag in the blast furnace,and the graphitization of coke is comparable to that of the final slag.The graphitization of coke starts from the surface of coke and leads to the formation of coke fines,and the graphitization degree of−74μm coke fines is the highest.The temperature has an effect on the reaction rate of coke solution loss,and the higher the temperature is,the faster the reaction rate is.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
Coke is the only solid charge component in the lower part of the blast furnace,and its strength is crucial to its production.Si and Al are the two most abundant elements in coke ash.The influences of these oxides on t...Coke is the only solid charge component in the lower part of the blast furnace,and its strength is crucial to its production.Si and Al are the two most abundant elements in coke ash.The influences of these oxides on the tensile strength of the coke matrix were studied by splitting tests.According to the Weibull analysis,with increasing Si and Al oxide concentrations,the fracture stress range of the coke widened,the upper and lower limits decreased,the probability of fracture under the same stress conditions increased,and the randomness and dispersion of strength increased.These results can be attributed to the inhibitory effect of ash during coal pyrolysis.Ash impedes the growth and contact of mesophase,leading to a decrease in graphitic carbon structures and an increase in edge carbon and aliphatic carbon structures in the resulting coke.Consequently,the overall ordering of the carbon structure is reduced.Moreover,SiO_(2)and Al_(2)O_(3)promoted the development of coke pores,thinned the coke pore wall,and significantly increased the proportion of large pores(>500μm).Moreover,Al_(2)O_(3)had more significant influences on the coke strength,carbon structure and stomatal ratio than SiO_(2).In addition,the position where the ash particles bonded to the carbon matrix easily produced cracks and holes,and the sharp edge of the matrix was likely to produce stress concentration points when subjected to an external force,leading to structural damage.Therefore,controlling the concentration of ash could effectively reduce the number of structural defects inside coke,which is conducive to improving the strength.展开更多
Forestry waste(FW)is a significant renewable energy source in China.The substitution of coal blends(BC)with forestry waste to produce metallurgical coke was investigated aiming at expanding alternative resources and r...Forestry waste(FW)is a significant renewable energy source in China.The substitution of coal blends(BC)with forestry waste to produce metallurgical coke was investigated aiming at expanding alternative resources and reducing CO_(2)emissions in ironmaking process.The BC with different ratios of FW were carbonized in a fixed bed reactor,and the physicochemical structure of the coke derived from FW/BC co-carbonization was characterized by Fourier transform infrared spectroscopy,X-ray photoelectron spectroscopy,solid-state^(13)C nuclear magnetic resonance,optical microscopy,and scanning electron microscopy.The results reveal that the suitable incorporation of FW in BC is 10 wt.%,and the index of coke quality exhibits a good correlation with the optical anisotropy index and the aromaticity of the as-obtained cokes.The partial substitution of BC with FW exhibits potential benefits for colloid formation,owing to the higher hydrogen in FW.However,as the substitution ratio of BC with FW increases,it inhibits coke agglomeration due to more tortuous stacked structures formation during volatile releasing process.Moreover,it was identified that the substitution of higher BC ratios with FW results in the partial replacement of aromatic carbons by oxygenlinked carbons and aliphatic carbons.This substitution leads to a reduction in the aromaticity of the as-obtained coke.展开更多
Coking wastewater,characterized by high biological toxicity,poses significant challenges for traditional biological treatment methods.This study developed a novel in-situ immobilized photocatalytic-algae-bacteria cons...Coking wastewater,characterized by high biological toxicity,poses significant challenges for traditional biological treatment methods.This study developed a novel in-situ immobilized photocatalytic-algae-bacteria consortia(P-ABC)system using a polyether polyurethane sponge as a carrier,aiming to enhance biological treatment efficiency for actual coking wastewater.Results showed a 16.8%increase in algal density(up to 1.51×10^(5) cells/mL)in the P-ABC system compared to non-coupled controls,with significantly improved microbial metabolic activity,confirming the carrier's exceptional biocompatibility.Compared to standalone algae-bacteria consortia systems,the P-ABC system achieved higher removal efficiencies for chemical oxygen demand(COD_(Cr),19.8%),total organic carbon(TOC,21.2%),and total nitrogen(TN,30.4%).These findings validate the system's potential for improving stable and efficient treatment of industrial wastewater.Furthermore,this study offers insights into bio-enhanced treatment technologies and provides a reference pathway for integrating advanced oxidation and biological processes.展开更多
The fractionating tower bottom in fluid catalytic cracking Unit (FCCU) is highly susceptible to coking due to the interplay of complex external operating conditions and internal physical properties. Consequently, quan...The fractionating tower bottom in fluid catalytic cracking Unit (FCCU) is highly susceptible to coking due to the interplay of complex external operating conditions and internal physical properties. Consequently, quantitative risk assessment (QRA) and predictive maintenance (PdM) are essential to effectively manage coking risks influenced by multiple factors. However, the inherent uncertainties of the coking process, combined with the mixed-frequency nature of distributed control systems (DCS) and laboratory information management systems (LIMS) data, present significant challenges for the application of data-driven methods and their practical implementation in industrial environments. This study proposes a hierarchical framework that integrates deep learning and fuzzy logic inference, leveraging data and domain knowledge to monitor the coking condition and inform prescriptive maintenance planning. The framework proposes the multi-layer fuzzy inference system to construct the coking risk index, utilizes multi-label methods to select the optimal feature dataset across the reactor-regenerator and fractionation system using coking risk factors as label space, and designs the parallel encoder-integrated decoder architecture to address mixed-frequency data disparities and enhance adaptation capabilities through extracting the operation state and physical properties information. Additionally, triple attention mechanisms, whether in parallel or temporal modules, adaptively aggregate input information and enhance intrinsic interpretability to support the disposal decision-making. Applied in the 2.8 million tons FCCU under long-period complex operating conditions, enabling precise coking risk management at the fractionating tower bottom.展开更多
Polystyrene(PS)waste was depolymerized using a low-temperature pyrolysis treatment(LTPT)to increase its caking index.The mechanism of caking index modification was revealed by using Fourier transform infrared spectros...Polystyrene(PS)waste was depolymerized using a low-temperature pyrolysis treatment(LTPT)to increase its caking index.The mechanism of caking index modification was revealed by using Fourier transform infrared spectroscopy,thermogravimetric(TG)analysis,pyrolysis-gas chromatography with mass spectrometric detection,and solid-state^(13)C nuclear magnetic resonance spectroscopy.The crucible coal-blending coking tests were carried out using an industrial coal mixture and the treated-PS with the highest caking index(PS300)or raw PS.Some properties of the resultant cokes were also analyzed.It was demonstrated that the caking index of PS dramatically increased by LTPT;however,exceeding 300℃ did not yield any benefit.The caking index increased due to the formation of the caking components,whose molecules are medium in size,caused by LTPT.Additionally,the coke reactivity index of the coke obtained from the mixture containing PS300 decreased by 5.1%relative to that of the coke made from the mixture with PS and the coke strength after reaction index of the former increased by 7.3% compared with that of the latter,suggesting that the ratio of depolymerized PS used for coal-blending coking could increase relative to that of PS.展开更多
Transition metal cobalt exhibits strong activation capabilities for alkanes,however,the instability of Co sites leads to sintering and coke deposition,resulting in rapid deactivation.Hierarchical zeolites,with their d...Transition metal cobalt exhibits strong activation capabilities for alkanes,however,the instability of Co sites leads to sintering and coke deposition,resulting in rapid deactivation.Hierarchical zeolites,with their diverse pore structures and high surface areas,are used to effectively anchor metals and enhance coke tolerance.Herein,a post-treatment method using an alkaline solution was employed to synthesize meso-microporous zeolite supports,which were subsequently loaded with Co species for propane dehydrogenation catalyst.The results indicate that the application of NaOH,an inorganic base,produces supports with a larger mesopore volume and more abundant hydroxyl nests compared to TPAOH,an organic base.UV-vis,Raman,and XPS analyses reveal that Co in the 0.5Co/SN-1-0.05 catalyst is mainly in the form of tetrahedral Co^(2+),which effectively activates C-H bonds.In contrast,the 0.5Co/S-1 catalyst contains mainly Co_(3)O_(4)species.Co^(2+)supported on hierarchical zeolites shows better propane conversion(58.6%)and propylene selectivity(>96%)compared to pure silica zeolites.Coke characterization indicates that hierarchical zeolites accumulate more coke,but it is mostly in the form of easily removable disordered carbon.The mesopores in the microporous zeolite support help disperse the active Co metal and facilitate coke removal during dehydrogenation,effectively preventing deactivation from sintering and coke coverage.展开更多
The problem of soil polycyclic aromatic hydrocarbon(PAH)pollution in coking plant sites has been widely studied in recent years,but there is a lack of research on the correlation between soil microorganisms,soil metab...The problem of soil polycyclic aromatic hydrocarbon(PAH)pollution in coking plant sites has been widely studied in recent years,but there is a lack of research on the correlation between soil microorganisms,soil metabolomics,and soil properties.Thus,in this study,the long-term impact of coke combustion on soil microbial community structure,enzyme activities,and metabolic pathways within a former coking plant site was investigated.Soil samples were collected from both the coking production area(CA group)and office area(OLA group),approximately 0 to 20 cm in depth.Compared with OLA group,elevated levels of 16 PAHs in the list of US EPA were detected by gas chromatography-mass spectrometry in the CA group.Several dominant microorganisms,such as Altererythrobacter,Lysobacter,and Sulfurifustis,were identified by 16 s ribosomal DNA sequencing in the CA group.The fatty acid biosynthesis pathway exhibited specific inhibition,while the phenylalanine metabolic pathwaywas promoted in response to PAH stress.Long-term PAH exposure led to the inhibition of soil urease activity.The co-occurrence network ofmicroorganisms revealed intricate patterns of co-metabolism and co-adaptation within complex bacterial communities,facilitating their adaptation to and decomposition of soil-borne PAHs.This research could provide valuable insights into the community characteristics andmetabolic mechanisms of microorganisms inhabiting PAH-polluted soil within coking plant sites.The findings enhance our understanding of the indigenous soil microbiome and its intricate network dynamics under the persistent stress of PAHs,contributing to a more comprehensive knowledge of soil ecosystems in such environments.展开更多
In this study,a string of Cr-Mnco-modified activated coke catalysts(XCryMn1-y/AC)were prepared to investigate toluene and Hg^(0) removal performance.Multifarious characterizations including XRD,TEM,SEM,in situ DRIFTS,...In this study,a string of Cr-Mnco-modified activated coke catalysts(XCryMn1-y/AC)were prepared to investigate toluene and Hg^(0) removal performance.Multifarious characterizations including XRD,TEM,SEM,in situ DRIFTS,BET,XPS and H_(2)-TPR showed that 4%Cr0.5Mn0.5/AC had excellent physicochemical properties and exhibited the best toluene and Hg^(0) removal efficiency at 200℃.By varying the experimental gas components and conditions,it was found that too large weight hourly space velocity would reduce the removal efficiency of toluene and Hg^(0).Although O_(2) promoted the abatement of toluene and Hg^(0),the inhibitory role of H_(2)O and SO_(2) offset the promoting effect of O_(2) to some extent.Toluene significantly inhibited Hg^(0) removal,resulting from that toluene was present at concentrations orders of magnitude greater than mercury’s or the catalyst was more prone to adsorb toluene,while Hg^(0) almost exerted non-existent influence on toluene elimination.The mechanistic analysis showed that the forms of toluene and Hg^(0) removal included both adsorption and oxidation,where the high-valent metal cations and oxygen vacancy clusters promoted the redox cycle of Cr^(3+)+Mn^(3+)/Mn^(4+)+Cr^(6+)+Mn^(2+),which facilitated the conversion and replenishment of reactive oxygen species in the oxidation process,and even the CrMn_(1.5)O_(4) spinel structure could provide a larger catalytic interface,thus enhancing the adsorption/oxidation of toluene and Hg^(0).Therefore,its excellent physicochemical properties make it a costeffective potential industrial catalyst with outstanding synergistic toluene and Hg^(0) removal performance and preeminent resistance to H_(2)O and SO_(2).展开更多
The self-reforming of coke oven gas(COG)in a gas-based shaft furnace was investigated,employing metallized iron as a catalyst.Thermodynamic analyses,supported by FactSage 8.3 calculations and regression modeling,were ...The self-reforming of coke oven gas(COG)in a gas-based shaft furnace was investigated,employing metallized iron as a catalyst.Thermodynamic analyses,supported by FactSage 8.3 calculations and regression modeling,were used to investigate the effects of temperature(700–1100℃),CO_(2)(3%–10%),and H_(2)O(1%–9%)concentrations on CH_(4) conversion efficiency.Results indicate that CH_(4) conversion exceeds 90%at temperatures above 1000℃,with CO_(2) and H_(2)O concentrations at 9%and 5%,respectively.During the reforming process,introducing CO_(2) provides additional oxygen,facilitating the oxidation of CH_(4),while H_(2)O enhances H_(2) production through the steam reforming pathway.Experimental findings reveal a CH_(4) conversion of 85.83%with a H_(2)/CO ratio of 5.44 at 1050℃.In addition,an optimal H_(2)O concentration of 6%yields the highest CH_(4) conversion of 84.24%,while CO_(2) exhibits minimal effects on promoting the reforming process.Increasing the metallization rate of pellets from 43%to 92%significantly enhances CH_(4) reforming.This is mainly due to the fact that metallized iron is vital in promoting CH_(4) dissociation and improving syngas yield by providing active sites for the redox cycle of CO_(2) and H_(2)O.展开更多
The removal of H_(2)S from coke oven gas (COG) is an important issue for the further utilization of COG. Zeolites could be used for industrial desulfurization owing to their high thermal stability and regenerability. ...The removal of H_(2)S from coke oven gas (COG) is an important issue for the further utilization of COG. Zeolites could be used for industrial desulfurization owing to their high thermal stability and regenerability. However, further analysis on the kinetics of deep desulfurization using zeolites is necessary to provide relevant information for industrial design. In this study, the desulfurization breakthrough curves of faujasite (FAU) zeolite in COG were measured using a fixed bed reactor. The adsorption isotherm was investigated using the Langmuir, Freundlich, Temkin, Dubinin-Radushkevich models. The adsorption saturated capacity of H_(2)S was inversely related to the temperature. The results show that the Langmuir model best fits the adsorption isotherm with a lower value of root-mean-square-error (RMSE) and Chi-Square (χ^(2)), and the calculated activation energy is 14.62 kJ·mol^(−1). The adsorption kinetics were investigated using pseudo-first-order (PFO), pseudo-second-order (PSO), Bangham and Weber-Morris models. The Bangham model fitted the kinetic data well, indicating that pore diffusion is an influential factor in the adsorption process. The Weber-Morris model suggests that the adsorption rate was not solely determined by the pore diffusion, but was also influenced by the active site on the FAU zeolite. The adsorption breakthrough curves under different gas flow rates were fitted using the bed depth service time (BDST) model, and it provides an accurate prediction of the breakthrough time with a small relative error. The results of thermodynamic analysis demonstrated the feasibility and spontaneity (ΔG<0) and exothermic (ΔH<0) nature of the adsorption process of the FAU zeolite for H_(2)S under COG.展开更多
基金supported by National Natural Science Foundation of China(22178002,22178001)Natural Science Foundation of Anhui Province(2308085Y19)Excellent Youth Research Project of Anhui Provincial Department of Education(2022AH030045).
文摘Hydrogen-enriched ironmaking presents a promising approach to mitigate coke consumption and carbon emission in blast furnace(BF)operations.This work investigated the relationship between the structural features of cokes and their reactivity towards solution loss(SL),especially under hydrogen-enriched atmospheres.Six cokes were characterized,and their SL behaviors were examined under varying atmospheres to elucidate the effects of hydrogen enrichment.The results indicate that an increase in fixed carbon content leads to a decrease in the coke reactivity index(CRI)and an increase in coke strength after reaction(CSR),in the CO_(2) atmosphere,the CSR of coke increases from 35.76%−62.83%,while in the 90CO_(2)/10H_(2) atmosphere,the CSR of coke increases from 65.67%−84.09%.There is a good linear relationship between CRI and microcrystalline structure parameters of coke.Cokes with larger crystalline size,lower amorphous content,and smaller optical texture index(OTI)values show enhanced resistance to degradation and maintain structural integrity in BF.Kinetic analysis performed with the shifted-modified-random pore model(S-MRPM)reveals that alterations in pore structure and intrinsic mineral composition significantly influence the reaction rate.The introduction of a small amount of water vapor raises SL rates,whereas a minor addition of hydrogen(<10%)decelerates SL due to its incomplete conversion to water vapor and the reduced partial pressure of the gasifying agent.Thermodynamic calculations also indicate that the introduced hydrogen does not convert into the same fraction of water vapor.The shift from chemical reaction control to gas diffusion control as the rate-determining step with rising temperatures during SL process was confirmed,and the introduction of hydrogen does not notably alter SL behavior.This result demonstrated that introducing a small amount of hydrogen(<10%)can mitigate SL rates,thereby enhancing coke strength and reducing coke consumption and carbon emissions.
文摘Shot cokes are frequently formed in the delayed coking unit treating the super viscous oil at PetroChina＇s Liaohe Petrochemical Company. Considerable work has been carded out to avoid the formation of shot cokes. The test results obtained have shown that the property of super viscous oil has played a key role in the formation of shot cokes. After adjusting and optimizing the process indices the operating regime of the delayed coking unit at a throughput of 118t/h of the super viscous oil is specified as follows： a reaction temperature of 498-502℃, a reaction pressure of 0.17-0.25 MPa, a recycle ratio of 0.5-0.6 and a fractionation tower bottom temperature of 355-365 ℃. In the meantime, the delayed coking process has adopted measures to enhance pre-fractionation of the feedstock to rationally remove light fractions and maintain a steady gas velocity in order to avoid the formation of shot cokes.
基金Item Sponsored by National Basic Research Program of China(2012CB720401)National Key Technology Research and Development Program in 12th Five-year Plan of China(2011BAC01B02)
文摘In order to effectively utilize the high reactivity coke, the gasification characteristics of high and low reactivity cokes were investigated at 1100 ℃. Low reactivity coke A and high reactivity coke B were chosen and charged into the reaction tube in two methods. The results indicated that the mass loss ratio of high reactivity coke in mixed cokes was more significant than that of single high reactivity coke in the middle stage of reaction. Nevertheless, the mass loss ratio of low reactivity coke in mixed cokes was less than that of single low reactivity coke. It was mainly attributed to gas diffusion and internal reaction of coke. When high and low reactivity cokes were mixed, the practical average mass loss ratio was nearly the same as the weighted average. The microscopic structures of coke indicated that with the increase of reaction time, the external and internal layers of low reactivity coke reacted more uniformly with CO2, whereas the reaction degree of external layer of high reactivity coke was obviously higher.
文摘It is difficult to distinguish tamping coke and top charging coke by conventional testing methods, such as cold strength, abrasion resistance, reactivity and strength after reaction. Some of tamping coket s properties were even bet-ter than those of top charging coke, hut from practical using effects of blast furnace, tamping coke was not as good as top charging coke. The reaction conditions were featured as high temperature, high alkali condition, intense reac-tion atmosphere and short time. Distribution of porosity in profile, microstructure and slag forming property of ash were analyzed and following conclusions were obtained. After alkali-rich reaction, there were obvious differences be- tween top charging coke and tamping coke in microstructure, The porosityts unevenness of tamping coke was greater than those of top charging coke, and tamping coke was with less and big pores in out space and inner part was dense with more throughout pores. After phase diagram and microstructure analysis, it could he obtained that ash forming characteristics of top charging coke were better than those of tamping coke, and top charging coke＇ s pores were blocked more seriously than those of tamping coke. From analysis of tuyere samples, it could be found that calcium content of ash in coke＇s pores was small and it should belong to coke＇s inherent ash; kalium （wκ =28%） was unusu-ally high in coke. so the situation of high alkali was close to real blast furnace reaction condition.
文摘A needle coke was graphitized at different heat treatment temperature (2 000℃ to 3 000℃). The electrochemical intercalation mechanism of Li into the graphitized coke has been studied in Li|1 mol·L 1 LiClO 4+ethylene carbonate/diethylene carbonate|graphite cells, using an in situ X Ray diffraction (XRD) technique.The study of Li C intercalation processes of the graphitized coke reveals that there are three major types of intercalation behavior.The first is uniformly intercalated at all Li C compounds in graphitized coke heated at 2 250℃;the second is obviously staging phenomenon during intercalation for the graphitized coke heated at 2 750℃; the third is cointercalation of solvated Li ion at high potential (>0.3V) and then lithium electrochemical intercalation at lower potential for that heated at 3 000℃, resulting in the decrease of capacity and efficiency of graphite negative electrode for lithium ion secondary battery.
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 Key Research and Development Program of China(No.2019YFC1804501)the National Natural Science Foundation of China(Nos.42122056 and U1901210)+2 种基金Guangdong Basic and Applied Basic Research Foundation(No.2021B1515020063)the Key Research and Development Program of Guangdong Province(No.2021B1111380003)the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(No.2017BT01Z032).
文摘Coking industry is a potential source of heavy metals(HMs)pollution.However,its impacts to the groundwater of surrounding residential areas have not been well understood.This study investigated the pollution characteristics and health risks of HMs in groundwater nearby a typical coking plant.Nine HMs including Fe,Zn,Mo,As,Cu,Ni,Cr,Pb and Cd were analyzed.The average concentration of total HMswas higher in the nearby area(244.27μg/L)than that of remote area away the coking plant(89.15μg/L).The spatial distribution of pollution indices including heavy metal pollution index(HPI),Nemerow index(NI)and contamination degree(CD),all demonstrated higher values at the nearby residential areas,suggesting coking activity could significantly impact the HMs distribution characteristics.Four sources of HMs were identified by Positive Matrix Factorization(PMF)model,which indicated coal washing and coking emission were the dominant sources,accounted for 40.4%,and 31.0%,respectively.Oral ingestionwas found to be the dominant exposure pathway with higher exposure dose to children than adults.Hazard quotient(HQ)values were below 1.0,suggesting negligible non-carcinogenic health risks,while potential carcinogenic risks were from Pb and Ni with cancer risk(CR)values>10−6.Monte Carlo simulation matched well with the calculated results with HMs concentrations to be the most sensitive parameters.This study provides insights into understanding how the industrial coking activities can impact the HMs pollution characteristics in groundwater,thus facilitating the implement of HMs regulation in coking industries.
基金supported by the National Natural Science Foundation of China(22308006,22278001)the Natural Science Foundation of Anhui Provincial Education Department(KJ2021A0407).
文摘This work proposed a strategy to improve the caking index of polyethylene terephthalate(PET)waste,in which low-temperature pyrolysis treatment(LTPT)was used to depolymerize PET waste.The mechanism of G modification was revealed combining thermogravimetric(TG)analysis,Fourier transform infrared spectroscopy,pyrolysis-gas chromatography with mass spectrometric detection,and solid-state 13C nuclear magnetic resonance spectroscopy.Furthermore,crucible coking experiments were also conducted using industrial coal mixture and treated PET with the optimum G(PET300)or raw PET to evaluate the applicability of PET waste in coal-blending coking.According to characterization results of coke reactivity(CR),coke strength after reaction(CSR)indices,TG-related curves,pore volumes,and Raman spectra of the resultant cokes,LTPT could greatly increase the G of PET,and the optimum temperature was 300℃.Specifically,compared with the coke obtained from the blend with PET,the CR of the coke produced from the blend with PET300 decreased by 4.9%,whereas the CSR of the increased by 7.4%,suggesting that LTPT could increase the proportion of PET used for coal-blending coking.The improvement in G is attributed to the changes in C-O/C=O ratio,aliphatic H and aromaticity caused by LTPT.
基金supported by the National Natural Science Foundation of China(Grant No.U1960205)China Baowu Low Carbon Metallurgy Innovation Foundation(Grant Nos.BWLCF202101 and BWLCF202104)China Minmetals Science and Technology Special Plan Foundation(Grant No.2020ZXA01).
文摘Pursuing green,low-carbon ironmaking technology primarily aims to reduce fuel ratios,especially coke ratios.Simultaneously,the reduction in coke ratios causes the coke layer in the blast furnace(BF)to become thinner,deteriorating the gas and liquid permeability of the burden column.This exacerbates coke degradation,significantly impacting the smelting process and increasing the demand for high-quality coke.To investigate the existence state of coke in the hearth,a 2500 m3 BF in China was taken as the research object,and three sets of samples at different heights of the hearth were obtained during planned outage.The results indicate that coke undergoes a significant degradation upon reaching the hearth.The proportion of coke particles smaller than 50 mm ranges from 81.22%to 89.50%.The proportion of coke particles larger than 20 mm decreases as the distance from the centerline of the tuyere increases,while the proportion of particles smaller than 10 mm increases with this distance.Additionally,the closer the bottom of the furnace is,the smaller the coke particle size becomes.The composition of slag filling the coke pores is similar to that of the final slag in the blast furnace,and the graphitization of coke is comparable to that of the final slag.The graphitization of coke starts from the surface of coke and leads to the formation of coke fines,and the graphitization degree of−74μm coke fines is the highest.The temperature has an effect on the reaction rate of coke solution loss,and the higher the temperature is,the faster the reaction rate is.
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 the National Natural Science Foundation of China(No.51974212)the China Baowu Low Carbon Metallurgy Innovation Foundation(No.BWLCF202116)+2 种基金the Science and Technology Major Project of Wuhan(No.2023020302020572)the Postdoctor Project of Hubei Province(No.2024HBBHCXA074)the Foundation of Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education(No.FMRUlab23-04).
文摘Coke is the only solid charge component in the lower part of the blast furnace,and its strength is crucial to its production.Si and Al are the two most abundant elements in coke ash.The influences of these oxides on the tensile strength of the coke matrix were studied by splitting tests.According to the Weibull analysis,with increasing Si and Al oxide concentrations,the fracture stress range of the coke widened,the upper and lower limits decreased,the probability of fracture under the same stress conditions increased,and the randomness and dispersion of strength increased.These results can be attributed to the inhibitory effect of ash during coal pyrolysis.Ash impedes the growth and contact of mesophase,leading to a decrease in graphitic carbon structures and an increase in edge carbon and aliphatic carbon structures in the resulting coke.Consequently,the overall ordering of the carbon structure is reduced.Moreover,SiO_(2)and Al_(2)O_(3)promoted the development of coke pores,thinned the coke pore wall,and significantly increased the proportion of large pores(>500μm).Moreover,Al_(2)O_(3)had more significant influences on the coke strength,carbon structure and stomatal ratio than SiO_(2).In addition,the position where the ash particles bonded to the carbon matrix easily produced cracks and holes,and the sharp edge of the matrix was likely to produce stress concentration points when subjected to an external force,leading to structural damage.Therefore,controlling the concentration of ash could effectively reduce the number of structural defects inside coke,which is conducive to improving the strength.
基金supported by the National Natural Science Foundation of China(Grant No.51706160)Natural Science Foundation of Wuhan(2024040701010057)+2 种基金Hubei Technological Innovation Special Fund(Grant Nos.2023AFA004,2023BCB106,and 2022BCA085)14th“Five-Year Plan’’Hubei Provincial Advantaged Characteristic Disciplines Project of Wuhan University of Science and Technology(2023C0108)Foundation of Hubei Key Laboratory of Industrial Fume&Dust Pollution Control(HBIK2020-02).
文摘Forestry waste(FW)is a significant renewable energy source in China.The substitution of coal blends(BC)with forestry waste to produce metallurgical coke was investigated aiming at expanding alternative resources and reducing CO_(2)emissions in ironmaking process.The BC with different ratios of FW were carbonized in a fixed bed reactor,and the physicochemical structure of the coke derived from FW/BC co-carbonization was characterized by Fourier transform infrared spectroscopy,X-ray photoelectron spectroscopy,solid-state^(13)C nuclear magnetic resonance,optical microscopy,and scanning electron microscopy.The results reveal that the suitable incorporation of FW in BC is 10 wt.%,and the index of coke quality exhibits a good correlation with the optical anisotropy index and the aromaticity of the as-obtained cokes.The partial substitution of BC with FW exhibits potential benefits for colloid formation,owing to the higher hydrogen in FW.However,as the substitution ratio of BC with FW increases,it inhibits coke agglomeration due to more tortuous stacked structures formation during volatile releasing process.Moreover,it was identified that the substitution of higher BC ratios with FW results in the partial replacement of aromatic carbons by oxygenlinked carbons and aliphatic carbons.This substitution leads to a reduction in the aromaticity of the as-obtained coke.
基金supported by the National Natural Science Foundation of China(No.22076113)Shaanxi Province Key R&D Program Project(No.2020NY-235)。
文摘Coking wastewater,characterized by high biological toxicity,poses significant challenges for traditional biological treatment methods.This study developed a novel in-situ immobilized photocatalytic-algae-bacteria consortia(P-ABC)system using a polyether polyurethane sponge as a carrier,aiming to enhance biological treatment efficiency for actual coking wastewater.Results showed a 16.8%increase in algal density(up to 1.51×10^(5) cells/mL)in the P-ABC system compared to non-coupled controls,with significantly improved microbial metabolic activity,confirming the carrier's exceptional biocompatibility.Compared to standalone algae-bacteria consortia systems,the P-ABC system achieved higher removal efficiencies for chemical oxygen demand(COD_(Cr),19.8%),total organic carbon(TOC,21.2%),and total nitrogen(TN,30.4%).These findings validate the system's potential for improving stable and efficient treatment of industrial wastewater.Furthermore,this study offers insights into bio-enhanced treatment technologies and provides a reference pathway for integrating advanced oxidation and biological processes.
基金financially supported by the Innovative Research Group Project of the National Natural Science Foundation of China (22021004)Sinopec Major Science and Technology Projects (321123-1)
文摘The fractionating tower bottom in fluid catalytic cracking Unit (FCCU) is highly susceptible to coking due to the interplay of complex external operating conditions and internal physical properties. Consequently, quantitative risk assessment (QRA) and predictive maintenance (PdM) are essential to effectively manage coking risks influenced by multiple factors. However, the inherent uncertainties of the coking process, combined with the mixed-frequency nature of distributed control systems (DCS) and laboratory information management systems (LIMS) data, present significant challenges for the application of data-driven methods and their practical implementation in industrial environments. This study proposes a hierarchical framework that integrates deep learning and fuzzy logic inference, leveraging data and domain knowledge to monitor the coking condition and inform prescriptive maintenance planning. The framework proposes the multi-layer fuzzy inference system to construct the coking risk index, utilizes multi-label methods to select the optimal feature dataset across the reactor-regenerator and fractionation system using coking risk factors as label space, and designs the parallel encoder-integrated decoder architecture to address mixed-frequency data disparities and enhance adaptation capabilities through extracting the operation state and physical properties information. Additionally, triple attention mechanisms, whether in parallel or temporal modules, adaptively aggregate input information and enhance intrinsic interpretability to support the disposal decision-making. Applied in the 2.8 million tons FCCU under long-period complex operating conditions, enabling precise coking risk management at the fractionating tower bottom.
基金supported by the National Natural Science Foundation of China(22308006 and 22278001)the Natural Science Foundation of Anhui Provincial Education Department(KJ2021A0407).
文摘Polystyrene(PS)waste was depolymerized using a low-temperature pyrolysis treatment(LTPT)to increase its caking index.The mechanism of caking index modification was revealed by using Fourier transform infrared spectroscopy,thermogravimetric(TG)analysis,pyrolysis-gas chromatography with mass spectrometric detection,and solid-state^(13)C nuclear magnetic resonance spectroscopy.The crucible coal-blending coking tests were carried out using an industrial coal mixture and the treated-PS with the highest caking index(PS300)or raw PS.Some properties of the resultant cokes were also analyzed.It was demonstrated that the caking index of PS dramatically increased by LTPT;however,exceeding 300℃ did not yield any benefit.The caking index increased due to the formation of the caking components,whose molecules are medium in size,caused by LTPT.Additionally,the coke reactivity index of the coke obtained from the mixture containing PS300 decreased by 5.1%relative to that of the coke made from the mixture with PS and the coke strength after reaction index of the former increased by 7.3% compared with that of the latter,suggesting that the ratio of depolymerized PS used for coal-blending coking could increase relative to that of PS.
基金supported by the National Natural Science Foundation of China(Nos.22035009,22178381)the National Key R&D Program of China(Nos.2021YFA1501301,2021YFC2901100)the State Key Laboratory of Heavy Oil Processing(No.2021-03).
文摘Transition metal cobalt exhibits strong activation capabilities for alkanes,however,the instability of Co sites leads to sintering and coke deposition,resulting in rapid deactivation.Hierarchical zeolites,with their diverse pore structures and high surface areas,are used to effectively anchor metals and enhance coke tolerance.Herein,a post-treatment method using an alkaline solution was employed to synthesize meso-microporous zeolite supports,which were subsequently loaded with Co species for propane dehydrogenation catalyst.The results indicate that the application of NaOH,an inorganic base,produces supports with a larger mesopore volume and more abundant hydroxyl nests compared to TPAOH,an organic base.UV-vis,Raman,and XPS analyses reveal that Co in the 0.5Co/SN-1-0.05 catalyst is mainly in the form of tetrahedral Co^(2+),which effectively activates C-H bonds.In contrast,the 0.5Co/S-1 catalyst contains mainly Co_(3)O_(4)species.Co^(2+)supported on hierarchical zeolites shows better propane conversion(58.6%)and propylene selectivity(>96%)compared to pure silica zeolites.Coke characterization indicates that hierarchical zeolites accumulate more coke,but it is mostly in the form of easily removable disordered carbon.The mesopores in the microporous zeolite support help disperse the active Co metal and facilitate coke removal during dehydrogenation,effectively preventing deactivation from sintering and coke coverage.
基金supported by the National Key Research and Development Program of China(Nos.2018YFA0901100 and 2018YFC1801103)the National Natural Science Foundation of China(Nos.22206202 and 22076216)。
文摘The problem of soil polycyclic aromatic hydrocarbon(PAH)pollution in coking plant sites has been widely studied in recent years,but there is a lack of research on the correlation between soil microorganisms,soil metabolomics,and soil properties.Thus,in this study,the long-term impact of coke combustion on soil microbial community structure,enzyme activities,and metabolic pathways within a former coking plant site was investigated.Soil samples were collected from both the coking production area(CA group)and office area(OLA group),approximately 0 to 20 cm in depth.Compared with OLA group,elevated levels of 16 PAHs in the list of US EPA were detected by gas chromatography-mass spectrometry in the CA group.Several dominant microorganisms,such as Altererythrobacter,Lysobacter,and Sulfurifustis,were identified by 16 s ribosomal DNA sequencing in the CA group.The fatty acid biosynthesis pathway exhibited specific inhibition,while the phenylalanine metabolic pathwaywas promoted in response to PAH stress.Long-term PAH exposure led to the inhibition of soil urease activity.The co-occurrence network ofmicroorganisms revealed intricate patterns of co-metabolism and co-adaptation within complex bacterial communities,facilitating their adaptation to and decomposition of soil-borne PAHs.This research could provide valuable insights into the community characteristics andmetabolic mechanisms of microorganisms inhabiting PAH-polluted soil within coking plant sites.The findings enhance our understanding of the indigenous soil microbiome and its intricate network dynamics under the persistent stress of PAHs,contributing to a more comprehensive knowledge of soil ecosystems in such environments.
基金supported by the Scientific Research Project of Hunan Provincial Department of Education (No.22B0458)the National Natural Science Foundation of China (No.52270102).
文摘In this study,a string of Cr-Mnco-modified activated coke catalysts(XCryMn1-y/AC)were prepared to investigate toluene and Hg^(0) removal performance.Multifarious characterizations including XRD,TEM,SEM,in situ DRIFTS,BET,XPS and H_(2)-TPR showed that 4%Cr0.5Mn0.5/AC had excellent physicochemical properties and exhibited the best toluene and Hg^(0) removal efficiency at 200℃.By varying the experimental gas components and conditions,it was found that too large weight hourly space velocity would reduce the removal efficiency of toluene and Hg^(0).Although O_(2) promoted the abatement of toluene and Hg^(0),the inhibitory role of H_(2)O and SO_(2) offset the promoting effect of O_(2) to some extent.Toluene significantly inhibited Hg^(0) removal,resulting from that toluene was present at concentrations orders of magnitude greater than mercury’s or the catalyst was more prone to adsorb toluene,while Hg^(0) almost exerted non-existent influence on toluene elimination.The mechanistic analysis showed that the forms of toluene and Hg^(0) removal included both adsorption and oxidation,where the high-valent metal cations and oxygen vacancy clusters promoted the redox cycle of Cr^(3+)+Mn^(3+)/Mn^(4+)+Cr^(6+)+Mn^(2+),which facilitated the conversion and replenishment of reactive oxygen species in the oxidation process,and even the CrMn_(1.5)O_(4) spinel structure could provide a larger catalytic interface,thus enhancing the adsorption/oxidation of toluene and Hg^(0).Therefore,its excellent physicochemical properties make it a costeffective potential industrial catalyst with outstanding synergistic toluene and Hg^(0) removal performance and preeminent resistance to H_(2)O and SO_(2).
基金financially supported by the National Natural Science Foundation of China(No.52004339)the Key Research and Development Project of Hunan Province,China(No.2022SK2075)+1 种基金China Baowu Low Carbon Metallurgy Innovation Foundation(BWLCF202216)Central South University Graduate Student Independent Exploration and Innovation Project(2024ZZTS0378).
文摘The self-reforming of coke oven gas(COG)in a gas-based shaft furnace was investigated,employing metallized iron as a catalyst.Thermodynamic analyses,supported by FactSage 8.3 calculations and regression modeling,were used to investigate the effects of temperature(700–1100℃),CO_(2)(3%–10%),and H_(2)O(1%–9%)concentrations on CH_(4) conversion efficiency.Results indicate that CH_(4) conversion exceeds 90%at temperatures above 1000℃,with CO_(2) and H_(2)O concentrations at 9%and 5%,respectively.During the reforming process,introducing CO_(2) provides additional oxygen,facilitating the oxidation of CH_(4),while H_(2)O enhances H_(2) production through the steam reforming pathway.Experimental findings reveal a CH_(4) conversion of 85.83%with a H_(2)/CO ratio of 5.44 at 1050℃.In addition,an optimal H_(2)O concentration of 6%yields the highest CH_(4) conversion of 84.24%,while CO_(2) exhibits minimal effects on promoting the reforming process.Increasing the metallization rate of pellets from 43%to 92%significantly enhances CH_(4) reforming.This is mainly due to the fact that metallized iron is vital in promoting CH_(4) dissociation and improving syngas yield by providing active sites for the redox cycle of CO_(2) and H_(2)O.
基金support of Ningbo Fareast Tech Catalyst Engineering Co.,Ltd,the National Natural Science Foundation of China(22478275)Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering(2022SX-TD014).
文摘The removal of H_(2)S from coke oven gas (COG) is an important issue for the further utilization of COG. Zeolites could be used for industrial desulfurization owing to their high thermal stability and regenerability. However, further analysis on the kinetics of deep desulfurization using zeolites is necessary to provide relevant information for industrial design. In this study, the desulfurization breakthrough curves of faujasite (FAU) zeolite in COG were measured using a fixed bed reactor. The adsorption isotherm was investigated using the Langmuir, Freundlich, Temkin, Dubinin-Radushkevich models. The adsorption saturated capacity of H_(2)S was inversely related to the temperature. The results show that the Langmuir model best fits the adsorption isotherm with a lower value of root-mean-square-error (RMSE) and Chi-Square (χ^(2)), and the calculated activation energy is 14.62 kJ·mol^(−1). The adsorption kinetics were investigated using pseudo-first-order (PFO), pseudo-second-order (PSO), Bangham and Weber-Morris models. The Bangham model fitted the kinetic data well, indicating that pore diffusion is an influential factor in the adsorption process. The Weber-Morris model suggests that the adsorption rate was not solely determined by the pore diffusion, but was also influenced by the active site on the FAU zeolite. The adsorption breakthrough curves under different gas flow rates were fitted using the bed depth service time (BDST) model, and it provides an accurate prediction of the breakthrough time with a small relative error. The results of thermodynamic analysis demonstrated the feasibility and spontaneity (ΔG<0) and exothermic (ΔH<0) nature of the adsorption process of the FAU zeolite for H_(2)S under COG.
