High-pressure impregnation, a new preparation method for sorbents to remove H2S from hot coal gas, is introduced in this paper. Semi-coke (SC) and ZnO is selected as the support and active component of sorbent, respec...High-pressure impregnation, a new preparation method for sorbents to remove H2S from hot coal gas, is introduced in this paper. Semi-coke (SC) and ZnO is selected as the support and active component of sorbent, respectively. The sorbent preparation process includes high-pressure impregnation, filtration, ovendry and calcination. The aim of this research is to primarily study the effects of the impregnation pressure on physical properties and desulfurization ability of the sorbent. The desulfurization experiment was carried out in a fixed-bed reactor at 500°C and a simulated coal gas used in this work was composed of CO (33 vol%), H2 (39 vol%), H2S (300 ppm in volume), and N2 (balance). Experimental results show that the pore structure of the SC support can be improved effectively and ZnO active component can be uniformly dispersed on the support, with the small particle size of 10-500 nm. Sorbents prepared using high-pressure impregnation have better desulfurization capacity and their active components have higher utilization rate. P20-ZnSC sorbent, obtained by high-pressure impregnation at 20 atm, has the best desulfurization ability with a sulfur capacity of 7.54 g S/100g sorbent and a breakthrough time of 44 h. Its desulfurization precision and efficiency of removing H2S from the middle temperature gases can reach <1 ppm and >99.7%, respectively, before sorbent breakthrough.展开更多
Zn-based sorbent (Z20SC) prepared through semi-coke support in 20 wt% zinc nitrate solution by high-pressure impregnation presents an excellent desulfurization capacity in hot coal gas,in which H2 S can not be nearly ...Zn-based sorbent (Z20SC) prepared through semi-coke support in 20 wt% zinc nitrate solution by high-pressure impregnation presents an excellent desulfurization capacity in hot coal gas,in which H2 S can not be nearly detected in the outlet gas before 20 h breakthrough time.The effects of the main operational conditions and the particle size of Z20SC sorbent on its desulfurization performances sorbent were investigated in a fixed-bed reactor and the desulfurization kinetics of Z20SC sorbent removing H2 S from hot coal gas was calculated based on experimental data.Results showed that the conversion of Z20SC sorbent desulfurization reaction increased with the decrease of the particle size of the sorbent and the increases of gas volumetric flow rate,reaction temperature and H 2 S content in inlet gas.Z20SC sorbent obtained from hydrothermal synthesis by high-pressure impregnation possessed much larger surface area and pore volume than semi-coke support,and they were significantly reduced after the desulfurization reaction.The equivalent grain model was reasonably used to analyze experimental data,in which k s=4.382×10-3 exp(-8.270×103/RgT) and Dep=1.262×10-4exp(1.522×104/RgT).It suggests that the desulfurization reaction of the Z20SC sorbent is mainly controlled by the chemical reaction in the initial stage and later by the diffusion through the reacted sorbent layer.展开更多
The occurrence modes of alkali and alkaline-earth metals(AAEMs) in coal relate to their release behavior and ash formation during combustion. To better understand the transformation of AAEMs,the release behavior of wa...The occurrence modes of alkali and alkaline-earth metals(AAEMs) in coal relate to their release behavior and ash formation during combustion. To better understand the transformation of AAEMs,the release behavior of water-soluble,HCl-soluble,HCl-insoluble AAEMs during Shenmu coal(SM coal) oxy-fuel combustion in the presence of SO2 and H2O in a drop-tube reactor was investigated through serial dissolution using H2O and HCl solutions. The results show that the release rates of AAEMs increase with an increase in temperature under the three atmospheres studied. The high release rates of Mg and Ca from SM coal are dependent on the high content of soluble Mg and Ca in SM coal. SO2 inhibits the release rates of AAEMs,while H2O promotes them. The effects of SO2 and H2O on the Na and K species are more evident than those on Mg and Ca species. All three types of AAEMs in coal can volatilize in the gas phase during coal combustion. The W-type AAEMs release excessively,whereas the release rates of I-type AAEMs are relatively lower. Different types of AAEM may interconvert through different pathways under certain conditions. Both SO2 and H2O promote the transformation reactions. The effect of SO2 was related to sulfate formation and the promotion by H2O occurs because of a decrease in the melting point of the solid as well as the reaction of H2O.展开更多
The Bunsen reaction is the center reaction for both the sulfur–iodine water splitting cycle for hydrogen production and the novel hydrogen sulfide splitting cycle for hydrogen and sulfuric acid production from the su...The Bunsen reaction is the center reaction for both the sulfur–iodine water splitting cycle for hydrogen production and the novel hydrogen sulfide splitting cycle for hydrogen and sulfuric acid production from the sulfur-containing gases.This paper reviews the research progress of the Bunsen reaction in recent 10–15 years.Researches were initially focused on the optimization of the operating conditions of the conventional Bunsen reaction requiring excessive water and iodine to improve the products separation efficiency and to avoid the side reactions and iodine vapor deposition.Alternative methods including electrochemical methods,precipitation methods,and non-aqueous solvent methods had their respective advantages,but still faced challenges.In development of the technology of H2S splitting cycle,dissolving iodine in toluene solvent could render the Bunsen reaction to occur with the flowable I2 stream at ambient temperature such that the side reactions and iodine vaporization can be avoided and the corrosion hazard lessened.It also prevented the Bunsen reaction from using excessive iodine and water.The products from the Bunsen reaction including HI,H2SO4,H2O,and toluene could be directly electrolyzed.展开更多
未加工的活性炭 A 和三修改活性炭上的 CO2 的吸附取样 B ，6号元素碳的化学符号，并且在从 303～333 K 和吸附的热力学 的温度的氘的符号用一台真空吸附仪器被调查了以便在工业气体在器官的包含硫的混合物的移动上关于 CO2 的效果获...未加工的活性炭 A 和三修改活性炭上的 CO2 的吸附取样 B ，6号元素碳的化学符号，并且在从 303～333 K 和吸附的热力学 的温度的氘的符号用一台真空吸附仪器被调查了以便在工业气体在器官的包含硫的混合物的移动上关于 CO2 的效果获得更多的信息。在对为 CO2 和它的体积的吸附的重要影响在修改的碳样品 B， 6 号元素碳的化学符号，和氘的符号上吸附了的碳样品表演使妊娠的活性组分都在未加工的碳样品 A 上比那大。在另一方面，象表面积，毛孔体积，和碳样品的微毛孔体积那样的物理参数不在 CO2 的吸附的数量上显示出影响。Dubinin-Radushkevich (医生) 方程是为在碳样品 A 和 B 上适合吸附数据的最好的模型，当 Freundlich 方程是为碳样品 6 号元素碳的化学符号和氘的符号上的吸附合适的最好时。用 Clapeyron 方程从吸附等温线导出的碳样品 A， B， 6 号元素碳的化学符号，和氘的符号上的 isosteric 稍微减少了装载的增加的表面。吸附的热躺在 10.5 和 28.4 kJ/mol 之间，与根本有最高的价值的碳样品氘的符号被学习的表面覆盖度。为碳与吸附联系的观察的熵变化取样 A， B，和 6 号元素碳的化学符号(在 7 ml/g 的表面覆盖度上面) 是比为活动吸附的理论价值低的。然而，它比为活动吸附的理论价值高，但是为碳样品氘的符号为局部性的吸附比理论价值降低。给词调音：二氧化碳；吸附；吸附的热；展开更多
The utilization of high-sulfur coal is becoming more urgent due to the excessive utilization of low-sulfur,high-quality coal resources,and sulfur removal from high-sulfur coal is the most important issue.This paper re...The utilization of high-sulfur coal is becoming more urgent due to the excessive utilization of low-sulfur,high-quality coal resources,and sulfur removal from high-sulfur coal is the most important issue.This paper reviews the speciation,forms and distribution of sulfur in coal,the sulfur removal from raw coal,the thermal transformation of sulfur during coal pyrolysis,and the sulfur regulation during coal-blending coking of high organic-sulfur coals.It was suggested that the proper characterization of sulfur in coal cannot be obtained only by either chemical method or instrumental characterization,which raises the need of a combination of current or newly adopted characterization methods.Different from the removal of inorganic sulfur from coal,the organic sulfur can only be partly removed by chemical technologies;and the coal structure and property,particularly high-sulfur coking coals which have caking ability,may be altered and affected by the pretreatment processes.Based on the interactions among the sulfur radicals,sulfur-containing and hydrogen-containing fragments during coal pyrolysis and the reactions with minerals or nascent char,regulating the sulfur transformation behavior in the process of thermal conversion is the most effective way to utilize high organic-sulfur coals in the coke-making industry.An in-situ regulation approach of sulfur transformation during coal-blending coking has been suggested.That is,the high volatile coals with an appropriate releasing temperature range of CH4 overlapping well with that of H2 S from high organic-sulfur coals is blended with high organic-sulfur coals,and the C–S/C–C bonds in some sulfur forms are catalytically broken and immediately hydrogenated by the hydrogencontaining radicals generated from high volatile coals.Wherein,the effect of mass transfer on sulfur regulation during the coking process should be considered for the larger-scale coking tests through optimizing the ratios of different coals in the coal blend.展开更多
Zn-Mn-Cu/SC(U) sorbent was hydrothermally synthesized by ultrasound-assisted high-pressure impregnation method with semi-coke(SC)as support and the mixed solution of zinc nitrate,manganese nitrate and copper nitrate a...Zn-Mn-Cu/SC(U) sorbent was hydrothermally synthesized by ultrasound-assisted high-pressure impregnation method with semi-coke(SC)as support and the mixed solution of zinc nitrate,manganese nitrate and copper nitrate as active component precursors.The desulfurization performances of hot coal gas on the prepared sorbent at a mid-temperature of 500°C were tested in fixed-bed reactor.Morphology and pore structure of the prepared sorbent were also characterized by TEM,N2adsorption/desorption isotherms and XRD.For comparison,the sorbent of Zn-Mn-Cu/SC prepared by conventional high-pressure impregnation was also evaluated and characterized in order to study the effects of ultrasound treatment.Zn-Mn-Cu/SC(U) sorbent prepared by high-pressure impregnation under ultrasound-assisted condition showed a better desulfurization performance than Zn-Mn-Cu/SC.It could remove H2 S from 1000×10-6m3/m3 to 0.1×10-6m3/m3 at 500°C and maintained for 12.5 h with the sulfur capacity of 7.74%,in which both the breakthrough time and sulfur capacity were about 32% and 51% higher than those of Zn-Mn-Cu/SC sorbent.The introduction of ultrasound during high-pressure impregnation process greatly improved the morphology and pore structure of the sorbent.The ultrasonic treatment made particle size of active components smaller and made them more evenly disperse on semi-coke support,which provided more opportunities to contact with H2S in coal-based gases.However,there were no any difference in compositions and existing forms of active components on the Zn-Mn-Cu/SC and Zn-Mn-Cu/SC(U) sorbents.展开更多
With lignite after vacuum drying as the raw material,a series of Zn-based sorbents were prepared by static impregnation,ultrasonic-assisted impregnation,bubbling-assisted impregnation and high-pressure impregnation.Th...With lignite after vacuum drying as the raw material,a series of Zn-based sorbents were prepared by static impregnation,ultrasonic-assisted impregnation,bubbling-assisted impregnation and high-pressure impregnation.The physical properties and the desulfurization performances of Zn-based sorbents were studied systematically by XRD,BET,AAS characterization techniques and the fixed-bed desulfurization evaluation apparatus.The sorbents obtained by high-pressure impregnation method have a larger specific surface area,pore volume and pore diameter comparing with other methods,which is conducive to the sulfidation reaction of hydrogen sulfide gas in the sorbent.The effects of pressure during the high-pressure impregnation and concentration of Zn(NO3)2 precursor solution on the sorbents properties and desulfurization behavior were investigated.The higher the impregnation pressure and the concentration of impregnation solution are,the greater the amount of the active components are uploaded.However,overhigh impregnation pressure can cause collapse and blocking of the carrier pore.The optimal operating condition of high-pressure impregnation method for preparing the sorbents was the impregnation pressure of 20 atm and the solution concentration of 41%.Under that condition,the sorbent had the best desulfurization ability with a sulfur capacity of 13.94 gS/100 gsorbent and a breakthrough time of 54 h.Its desulfurization precision and efficiency of removing H2S before sorbent breakthrough from the middle temperature gases of 400℃ can reach<5 ppm and>99%,respectively.Sorbents could be regenerated under the condition of 1 vol%O2,20 vol% H2O,0.5 vol% NH3,and N2balance gas.The regenerated sorbent could be used for repeated absorption of H2S with a slight decrease in desulfurization effect.展开更多
OBJECTIVE:To evaluate the association of X-ray cross-complementing group 1(XRCC1)Arg399Gln,Arg194Trp and Arg280His polymorphisms with the risk of glioma.DATA SOURCES:A systematic literature search of papers published ...OBJECTIVE:To evaluate the association of X-ray cross-complementing group 1(XRCC1)Arg399Gln,Arg194Trp and Arg280His polymorphisms with the risk of glioma.DATA SOURCES:A systematic literature search of papers published from January 2000 to August2012 in PubMed,Embase,China National Knowledge Infrastructure database,and Wanfang database was performed.The key words used were"glioma","polymorphism",and"XRCC1 or X-ray repair cross-complementing group 1".References cited in the retrieved articles were screened manually to identify additional eligible studies.STUDY SELECTION:Studies were identified according to the following inclusion criteria:case-control design was based on unrelated individuals;and genotype frequency was available to estimate an odds ratio(OR)and 95%confidence interval(CI).Meta-analysis was performed for the selected studies after strict screening.Dominant and recessive genetic models were used and the relationship between homozygous mutant genotype frequencies and mutant gene frequency and glioma incidence was investigated.We chose the fixed or random effect model according to the heterogeneity to calculate OR and 95%CI,and sensitivity analyses were conducted.Publication bias was examined using the inverted funnel plot and the Egger’s test using Stata 12.0 software.MAIN OUTCOME MEASURES:Association of XRCC1 Arg399Gln,Arg194Trp,and Arg280His polymorphisms with the risk of glioma,and subgroup analyses were performed according to different ethnicities of the subjects.RESULTS:Twelve articles were included in the meta-analysis.Eleven of the articles were concerned with the Arg399Gln polymorphism and glioma onset risk.Significantly increased glioma risks were found only in the dominant model(Gln/Gln+Gln/Arg versus Arg/Arg:OR=1.26,95%CI=1.03-1.54,P=0.02).In the subgroup analysis by ethnicity,significantly increased risk was found in Asian subjects in the recessive(OR=1.46,95%CI=1.04-2.45,P=0.03)and dominant models(OR=1.40,95%CI=1.10-1.78,P=0.007),and homozygote contrast(OR=1.69,95%CI=1.17-2.45,P=0.005),but not in Caucasian subjects.For association of the Arg194Trp(eight studies)and Arg280His(four studies)polymorphisms with glioma risk,the meta-analysis did not reveal a significant effect in the allele contrast,the recessive genetic model,the dominant genetic model,or homozygote contrast.CONCLUSION:The XRCC1 Arg399Gln polymorphism may be a biomarker of glioma susceptibility,especially in Asian populations.The Arg194Trp and Arg280His polymorphisms were not associated with overall glioma risk.展开更多
Ceria-zirconia solid solution has been prepared by the urea grind combustion and citric acid sol-gel methods for catalytic applications as oxygen storage/release materials in this study. The properties and oxygen stor...Ceria-zirconia solid solution has been prepared by the urea grind combustion and citric acid sol-gel methods for catalytic applications as oxygen storage/release materials in this study. The properties and oxygen storage/release capacities of samples with different Zr contents were characterized and evaluated by X-ray diffraction(XRD), N_2 adsorption, scanning electron microscopy(SEM), Raman spectroscopy, and insitu CO–CO_2 looping test. The results demonstrate that the samples prepared by two methods are all of excellent lattice [O] release/storage properties and maintain good long-term cycle stability. But the preparation method significantly impacts the homogeneity of samples related to their redox properties and the content of Zr over 20%, which greatly changed the properties of ceria-zirconia solid solutions and caused their changing of crystalline symmetry from cubic to tetragonal. The samples prepared by citric acid solgel method are of more homogeneous particle sizes and higher specific surface areas than that by urea grind combustion method, which is benefit to the oxygen release rather than oxygen storage. The bulk oxygen amount migrated to surface increases with the increasing Zr content, however, the amount of lattice oxygen migration decreases when Zr content is over 20%. When Zr content is 20%, the differences of storage/release capacities from two different preparation methods are reduced at high temperature in the long-term loop reaction.展开更多
OBJECTIVE:To analyze the constituents of volatile oils extracted from Yuan Zhi(Radix Polygalae),Shi Chang Pu(Acorus Tatarinowii),and a mixture of the two herbs.METHODS:The volatile oils were extracted using supercriti...OBJECTIVE:To analyze the constituents of volatile oils extracted from Yuan Zhi(Radix Polygalae),Shi Chang Pu(Acorus Tatarinowii),and a mixture of the two herbs.METHODS:The volatile oils were extracted using supercritical fluid extraction(SFE) with CO 2,and the constituents of the volatile oil extracts were analyzed by gas chromatography-mass spectrometry(GC-MS).The relative content of each component was calculated using peak area normalization.RESULTS:The optimized SFE conditions were 45 MPa at 35℃ for 2 h.Twenty-four compounds were identified in the extract from the Yuan Zhi(Radix Polygalae) and Shi Chang Pu(Acorus Tatarinowii) mixture,and six of these had relative contents >1.These compounds were 1,2-dimethoxy-4-(2-propenyl)-benzene;1,2,3-trimethoxy-5-(2-propenyl)-benzene;β-asarone;(Z,Z) 9,12-octadecadienoic acid;(Z) 6-octadecenoic acid;and ethyl oleate.Combination of the herbs increased the number of pharmacologically active substances in the extract and decreased the number of compounds with one benzene ring compared with the extracts from the individual herbs.CONCLUSION:These results indicate there is a synergistic relationship among the compounds in these herbs.展开更多
Higher concentrations of Hg can be emitted from coal pyrolysis or gasification than from coal combustion, especially elemental Hg. Highly efficient Hg removal technology from coal-derived fuel gas is thus of great imp...Higher concentrations of Hg can be emitted from coal pyrolysis or gasification than from coal combustion, especially elemental Hg. Highly efficient Hg removal technology from coal-derived fuel gas is thus of great importance. Based on the very excellent Hg removal ability of Pd and the high adsorption abilities of activated carbon(AC) for H2 S and Hg, a series of Pd/AC sorbents was prepared by using pore volume impregnation, and their performance in capturing Hg and H2 S from coal-derived fuel gas was investigated using a laboratory-scale fixed-bed reactor. The effects of loading amount, reaction temperature and reaction atmosphere on Hg removal from coal-derived fuel gas were studied. The sorbents were characterized by N2 adsorption, X-ray diffraction(XRD) and X-ray photoelectron spectroscopy(XPS). The results indicated that the efficiency of Hg removal increased with the increasing of Pd loading amount, but the effective utilization rate of the active component Pd decreased significantly at the same time. High temperature had a negative influence on the Hg removal. The efficiency of Hg removal in the N2–H2S–H2–CO–Hg atmosphere(simulated coal gas) was higher than that in N2–H2S–Hg and N2–Hg atmospheres, which showed that H2 and CO, with their reducing capacity, could benefit promote the removal of Hg. The XPS results suggested that there were two different ways of capturing Hg over sorbents in N2–H2S–Hg and N2–Hg atmospheres.展开更多
Hierarchical porous carbon(HPC)from bituminous coal was designed and synthesized through pyrolysis foaming and KOH activation.The obtained HPC(NCF-KOH)were characterized by a high specific surface area(S_(BET))of 3472...Hierarchical porous carbon(HPC)from bituminous coal was designed and synthesized through pyrolysis foaming and KOH activation.The obtained HPC(NCF-KOH)were characterized by a high specific surface area(S_(BET))of 3472.41 m^(2)/g,appropriate mesopores with V_(mes)/V_(total)of 57%,and a proper amount of surface oxygen content(10.03%).This NCF-KOH exhibited a high specific capacitance of 487 F/g at 1.0 A/g and a rate capability of 400 F/g at 50 A/g based on the three-electrode configuration.As an electrode for a symmetric capacitor,a specific capacitance of 299 F/g at 0.5 A/g was exhibited,and the specific capacitance retained 96%of the initial capacity at 5 A/g after 10,000 cycles.Furthermore,under the power density of 249.6 W/kg in 6 mol/L KOH,a high energy density of 10.34 Wh/kg was obtained.The excellent charge storage capability benefited from its interconnected hierarchical pore structure with high accessible surface area and the suitable amount of oxygen-containing functional groups.Thus,an effective strategy to synthesize HPC for high-performance supercapacitors serves as a promising way of converting coal into advanced carbon materials.展开更多
A series of iron-manganese-based sorbents were prepared by co-precipitation and physical mixing method,and used for H_(2)S removal from hot coal gas.The sulfidation tests were carried out in a fixed-bed reactor with s...A series of iron-manganese-based sorbents were prepared by co-precipitation and physical mixing method,and used for H_(2)S removal from hot coal gas.The sulfidation tests were carried out in a fixed-bed reactor with space velocity of 2000 h^(-1)(STP).The results show that the suitable addition of manganese oxide in iron-based sorbent can decrease H_(2)S and COS concentration in exit before breakthrough due to its simultaneous reaction capability with H_(2)S and COS.Fe3O4 and MnO are the initial active components in iron-manganese-based sorbent,and FeO and Fe are active components formed by reduction during sulfidation.The crystal phases of iron affect obviously their desulfurization capacity.The reducibility of sorbent changes with the content of MnO in sorbent.S7F3M and S3F7M have bigger sulfur capacities(32.68 and 32.30 gS/100 g total active component),while S5F5M has smaller sulfur capacity(21.92 gS/100 g total active component).S7F3M sorbent has stable sulfidation performance in three sulfidation-regeneration cycles and no apparent structure degradation.The sulfidation performance of ironmanganese-based sorbent is also related with its specific surface area and pore volume.展开更多
OBJECTIVE: To study the effects of the drying processing in terms operational parameters on the bioactive constituents of six Yuanzhi(Radix Palygalae)samples across China.METHODS: Six Yuanzhi(Radix Palygalae) samples ...OBJECTIVE: To study the effects of the drying processing in terms operational parameters on the bioactive constituents of six Yuanzhi(Radix Palygalae)samples across China.METHODS: Six Yuanzhi(Radix Palygalae) samples were investigated using thermogravimetry analysis. The heating courses were set in two ways: thetemperature-programmed process from room temperature to 150℃,and the constant-temperature course at 50℃, 70℃ and 90℃.RESULTS: The peak temperature of six Yuanzhi(Radix Palygalae) samples ranged from 78℃ to 88℃.The mass loss rate ofYuanzhi(Radix Palygalae) alcohol-soluble extract was significantly increased when heated at 90℃. Four types of bioactive ingredients were detected in volatile oils of Yuanzhi(Radix Palygalae) sample from Shanxi province by Gas Chromatography-mass spectrometry analysis. Fourier Transform Infrared Spectroscopy results showed that the drying temperature exerted a great influence on types and amount of ingredients of Yuanzhi(Radix Palygalae). The kinetic study showed that the constant-temperature drying process ofYuanzhi Radix Palygalae) samples could be well described by the Page Model, especially for the drying process at 50℃, in which R2and SD values were more than 0.98 and less than 0.04, respectively. The drying constant k of three Yuanzhi(Radix Palygalae) samples from Shanxi, Gansu and Shaanxi provinces in China was corresponding to the Arrhenius equation, and their activation energies were28.07, 25.38 and 21.48 kJ/mol, respectively.CONCLUSION: The drying process of Yuanzhi(Radix Palygalae) was very important for bioactive ingredients improvement in Yuanzhi(Radix Palygalae). Temperature was a thermodynamic property significantly affecting the process.展开更多
In poly-generation and integrated gasificationcombined cycle(IGCC)systems for clean energy conversion,it is essential to remove impurities such as sulfur species from hot coal gases prior to entering the subsequent un...In poly-generation and integrated gasificationcombined cycle(IGCC)systems for clean energy conversion,it is essential to remove impurities such as sulfur species from hot coal gases prior to entering the subsequent units.This paper provides a comprehensive review on previous studies on high temperature removal of hydrogen sulfide from high temperature coal gases using iron-based sorbents.A two-step desulphurization process for hot coal gas cleanup is highlighted,which is integrated with direct production of elemental sulfur during regeneration of ironbased sorbents in the primary desulphurization step.Different kinetic modeling approaches for sulfidation and regeneration were compared.Limited research on activated carbon supported sorbents was also briefly summarized.展开更多
基金supported by the financial support of National Basic Research Program of China (2012CB723105)National Natural Science Foundation of China (20976117)+1 种基金Shanxi Province Natural Science Foundation(2010011014-3)Shanxi Province Basic Conditions Platform for Science and Technology Project (2010091015)
文摘High-pressure impregnation, a new preparation method for sorbents to remove H2S from hot coal gas, is introduced in this paper. Semi-coke (SC) and ZnO is selected as the support and active component of sorbent, respectively. The sorbent preparation process includes high-pressure impregnation, filtration, ovendry and calcination. The aim of this research is to primarily study the effects of the impregnation pressure on physical properties and desulfurization ability of the sorbent. The desulfurization experiment was carried out in a fixed-bed reactor at 500°C and a simulated coal gas used in this work was composed of CO (33 vol%), H2 (39 vol%), H2S (300 ppm in volume), and N2 (balance). Experimental results show that the pore structure of the SC support can be improved effectively and ZnO active component can be uniformly dispersed on the support, with the small particle size of 10-500 nm. Sorbents prepared using high-pressure impregnation have better desulfurization capacity and their active components have higher utilization rate. P20-ZnSC sorbent, obtained by high-pressure impregnation at 20 atm, has the best desulfurization ability with a sulfur capacity of 7.54 g S/100g sorbent and a breakthrough time of 44 h. Its desulfurization precision and efficiency of removing H2S from the middle temperature gases can reach <1 ppm and >99.7%, respectively, before sorbent breakthrough.
基金supported by the National Basic Research Program of China (2012CB723105)the National Natural Science Foundation of China(20976117)+1 种基金Shanxi Province Natural Science Foundation (2010011014-3)Shanxi Province Basic Conditions Platform for Science and Technology Project(2010091015)
文摘Zn-based sorbent (Z20SC) prepared through semi-coke support in 20 wt% zinc nitrate solution by high-pressure impregnation presents an excellent desulfurization capacity in hot coal gas,in which H2 S can not be nearly detected in the outlet gas before 20 h breakthrough time.The effects of the main operational conditions and the particle size of Z20SC sorbent on its desulfurization performances sorbent were investigated in a fixed-bed reactor and the desulfurization kinetics of Z20SC sorbent removing H2 S from hot coal gas was calculated based on experimental data.Results showed that the conversion of Z20SC sorbent desulfurization reaction increased with the decrease of the particle size of the sorbent and the increases of gas volumetric flow rate,reaction temperature and H 2 S content in inlet gas.Z20SC sorbent obtained from hydrothermal synthesis by high-pressure impregnation possessed much larger surface area and pore volume than semi-coke support,and they were significantly reduced after the desulfurization reaction.The equivalent grain model was reasonably used to analyze experimental data,in which k s=4.382×10-3 exp(-8.270×103/RgT) and Dep=1.262×10-4exp(1.522×104/RgT).It suggests that the desulfurization reaction of the Z20SC sorbent is mainly controlled by the chemical reaction in the initial stage and later by the diffusion through the reacted sorbent layer.
基金support for this research from the Natural Science Foundation of China (U1261110)the Natural Science Foundation of Shanxi Province (20130110422)the Foundation of State Key Laboratory of Coal Combustion (FSKLCC-0914)
文摘The occurrence modes of alkali and alkaline-earth metals(AAEMs) in coal relate to their release behavior and ash formation during combustion. To better understand the transformation of AAEMs,the release behavior of water-soluble,HCl-soluble,HCl-insoluble AAEMs during Shenmu coal(SM coal) oxy-fuel combustion in the presence of SO2 and H2O in a drop-tube reactor was investigated through serial dissolution using H2O and HCl solutions. The results show that the release rates of AAEMs increase with an increase in temperature under the three atmospheres studied. The high release rates of Mg and Ca from SM coal are dependent on the high content of soluble Mg and Ca in SM coal. SO2 inhibits the release rates of AAEMs,while H2O promotes them. The effects of SO2 and H2O on the Na and K species are more evident than those on Mg and Ca species. All three types of AAEMs in coal can volatilize in the gas phase during coal combustion. The W-type AAEMs release excessively,whereas the release rates of I-type AAEMs are relatively lower. Different types of AAEM may interconvert through different pathways under certain conditions. Both SO2 and H2O promote the transformation reactions. The effect of SO2 was related to sulfate formation and the promotion by H2O occurs because of a decrease in the melting point of the solid as well as the reaction of H2O.
基金financial supports from the National Natural Science Foundation of China(21576183)Natural Science and Technology Research Council of Canada(STPGP-350428-07)
文摘The Bunsen reaction is the center reaction for both the sulfur–iodine water splitting cycle for hydrogen production and the novel hydrogen sulfide splitting cycle for hydrogen and sulfuric acid production from the sulfur-containing gases.This paper reviews the research progress of the Bunsen reaction in recent 10–15 years.Researches were initially focused on the optimization of the operating conditions of the conventional Bunsen reaction requiring excessive water and iodine to improve the products separation efficiency and to avoid the side reactions and iodine vapor deposition.Alternative methods including electrochemical methods,precipitation methods,and non-aqueous solvent methods had their respective advantages,but still faced challenges.In development of the technology of H2S splitting cycle,dissolving iodine in toluene solvent could render the Bunsen reaction to occur with the flowable I2 stream at ambient temperature such that the side reactions and iodine vaporization can be avoided and the corrosion hazard lessened.It also prevented the Bunsen reaction from using excessive iodine and water.The products from the Bunsen reaction including HI,H2SO4,H2O,and toluene could be directly electrolyzed.
基金financial support of National Natural Science Foundation of China(U1910201,21878208)Transformation of Scientific and Technological Achievements Programs of Higher Education Institutions in Shanxi(TSTAP)Shanxi Province Science Foundation for Key Program(201901D111001(ZD))。
文摘The utilization of high-sulfur coal is becoming more urgent due to the excessive utilization of low-sulfur,high-quality coal resources,and sulfur removal from high-sulfur coal is the most important issue.This paper reviews the speciation,forms and distribution of sulfur in coal,the sulfur removal from raw coal,the thermal transformation of sulfur during coal pyrolysis,and the sulfur regulation during coal-blending coking of high organic-sulfur coals.It was suggested that the proper characterization of sulfur in coal cannot be obtained only by either chemical method or instrumental characterization,which raises the need of a combination of current or newly adopted characterization methods.Different from the removal of inorganic sulfur from coal,the organic sulfur can only be partly removed by chemical technologies;and the coal structure and property,particularly high-sulfur coking coals which have caking ability,may be altered and affected by the pretreatment processes.Based on the interactions among the sulfur radicals,sulfur-containing and hydrogen-containing fragments during coal pyrolysis and the reactions with minerals or nascent char,regulating the sulfur transformation behavior in the process of thermal conversion is the most effective way to utilize high organic-sulfur coals in the coke-making industry.An in-situ regulation approach of sulfur transformation during coal-blending coking has been suggested.That is,the high volatile coals with an appropriate releasing temperature range of CH4 overlapping well with that of H2 S from high organic-sulfur coals is blended with high organic-sulfur coals,and the C–S/C–C bonds in some sulfur forms are catalytically broken and immediately hydrogenated by the hydrogencontaining radicals generated from high volatile coals.Wherein,the effect of mass transfer on sulfur regulation during the coking process should be considered for the larger-scale coking tests through optimizing the ratios of different coals in the coal blend.
基金supported by the National Basic Research Program of China(2012CB723105)the National Natural Science Foundation of China(20976117)the Technological Innovation Programs of Higher Education Institutions in Shanxi(2013JYT113)
文摘Zn-Mn-Cu/SC(U) sorbent was hydrothermally synthesized by ultrasound-assisted high-pressure impregnation method with semi-coke(SC)as support and the mixed solution of zinc nitrate,manganese nitrate and copper nitrate as active component precursors.The desulfurization performances of hot coal gas on the prepared sorbent at a mid-temperature of 500°C were tested in fixed-bed reactor.Morphology and pore structure of the prepared sorbent were also characterized by TEM,N2adsorption/desorption isotherms and XRD.For comparison,the sorbent of Zn-Mn-Cu/SC prepared by conventional high-pressure impregnation was also evaluated and characterized in order to study the effects of ultrasound treatment.Zn-Mn-Cu/SC(U) sorbent prepared by high-pressure impregnation under ultrasound-assisted condition showed a better desulfurization performance than Zn-Mn-Cu/SC.It could remove H2 S from 1000×10-6m3/m3 to 0.1×10-6m3/m3 at 500°C and maintained for 12.5 h with the sulfur capacity of 7.74%,in which both the breakthrough time and sulfur capacity were about 32% and 51% higher than those of Zn-Mn-Cu/SC sorbent.The introduction of ultrasound during high-pressure impregnation process greatly improved the morphology and pore structure of the sorbent.The ultrasonic treatment made particle size of active components smaller and made them more evenly disperse on semi-coke support,which provided more opportunities to contact with H2S in coal-based gases.However,there were no any difference in compositions and existing forms of active components on the Zn-Mn-Cu/SC and Zn-Mn-Cu/SC(U) sorbents.
基金supported by the National Basic Research Program of China(2012CB723105)the National Natural Science Foundation of China(20976117)Shanxi Graduates Excellent Innovation Project of China(tyut-rc201018a)
文摘With lignite after vacuum drying as the raw material,a series of Zn-based sorbents were prepared by static impregnation,ultrasonic-assisted impregnation,bubbling-assisted impregnation and high-pressure impregnation.The physical properties and the desulfurization performances of Zn-based sorbents were studied systematically by XRD,BET,AAS characterization techniques and the fixed-bed desulfurization evaluation apparatus.The sorbents obtained by high-pressure impregnation method have a larger specific surface area,pore volume and pore diameter comparing with other methods,which is conducive to the sulfidation reaction of hydrogen sulfide gas in the sorbent.The effects of pressure during the high-pressure impregnation and concentration of Zn(NO3)2 precursor solution on the sorbents properties and desulfurization behavior were investigated.The higher the impregnation pressure and the concentration of impregnation solution are,the greater the amount of the active components are uploaded.However,overhigh impregnation pressure can cause collapse and blocking of the carrier pore.The optimal operating condition of high-pressure impregnation method for preparing the sorbents was the impregnation pressure of 20 atm and the solution concentration of 41%.Under that condition,the sorbent had the best desulfurization ability with a sulfur capacity of 13.94 gS/100 gsorbent and a breakthrough time of 54 h.Its desulfurization precision and efficiency of removing H2S before sorbent breakthrough from the middle temperature gases of 400℃ can reach<5 ppm and>99%,respectively.Sorbents could be regenerated under the condition of 1 vol%O2,20 vol% H2O,0.5 vol% NH3,and N2balance gas.The regenerated sorbent could be used for repeated absorption of H2S with a slight decrease in desulfurization effect.
基金The Fundamental Research Funds for Jilin University in China,No.450060445246the High-Tech Industrial Development Project of Jilin Province in China,No.20090633+1 种基金the Scientific Research Foundation of Jilin Province in China,No.20130206001YY,20120713 and 200905169the Scientific Research Foundation of Changchun in China,No.12SF29
文摘OBJECTIVE:To evaluate the association of X-ray cross-complementing group 1(XRCC1)Arg399Gln,Arg194Trp and Arg280His polymorphisms with the risk of glioma.DATA SOURCES:A systematic literature search of papers published from January 2000 to August2012 in PubMed,Embase,China National Knowledge Infrastructure database,and Wanfang database was performed.The key words used were"glioma","polymorphism",and"XRCC1 or X-ray repair cross-complementing group 1".References cited in the retrieved articles were screened manually to identify additional eligible studies.STUDY SELECTION:Studies were identified according to the following inclusion criteria:case-control design was based on unrelated individuals;and genotype frequency was available to estimate an odds ratio(OR)and 95%confidence interval(CI).Meta-analysis was performed for the selected studies after strict screening.Dominant and recessive genetic models were used and the relationship between homozygous mutant genotype frequencies and mutant gene frequency and glioma incidence was investigated.We chose the fixed or random effect model according to the heterogeneity to calculate OR and 95%CI,and sensitivity analyses were conducted.Publication bias was examined using the inverted funnel plot and the Egger’s test using Stata 12.0 software.MAIN OUTCOME MEASURES:Association of XRCC1 Arg399Gln,Arg194Trp,and Arg280His polymorphisms with the risk of glioma,and subgroup analyses were performed according to different ethnicities of the subjects.RESULTS:Twelve articles were included in the meta-analysis.Eleven of the articles were concerned with the Arg399Gln polymorphism and glioma onset risk.Significantly increased glioma risks were found only in the dominant model(Gln/Gln+Gln/Arg versus Arg/Arg:OR=1.26,95%CI=1.03-1.54,P=0.02).In the subgroup analysis by ethnicity,significantly increased risk was found in Asian subjects in the recessive(OR=1.46,95%CI=1.04-2.45,P=0.03)and dominant models(OR=1.40,95%CI=1.10-1.78,P=0.007),and homozygote contrast(OR=1.69,95%CI=1.17-2.45,P=0.005),but not in Caucasian subjects.For association of the Arg194Trp(eight studies)and Arg280His(four studies)polymorphisms with glioma risk,the meta-analysis did not reveal a significant effect in the allele contrast,the recessive genetic model,the dominant genetic model,or homozygote contrast.CONCLUSION:The XRCC1 Arg399Gln polymorphism may be a biomarker of glioma susceptibility,especially in Asian populations.The Arg194Trp and Arg280His polymorphisms were not associated with overall glioma risk.
基金the financial supports of National Natural Science Foundation of China(21406152)Research Project Supported by Shanxi Scholarship Council of China(2014-028)Shanxi Coal Based Key Scientific and Technological Project(MJH2014-02,MJH2015-04)
文摘Ceria-zirconia solid solution has been prepared by the urea grind combustion and citric acid sol-gel methods for catalytic applications as oxygen storage/release materials in this study. The properties and oxygen storage/release capacities of samples with different Zr contents were characterized and evaluated by X-ray diffraction(XRD), N_2 adsorption, scanning electron microscopy(SEM), Raman spectroscopy, and insitu CO–CO_2 looping test. The results demonstrate that the samples prepared by two methods are all of excellent lattice [O] release/storage properties and maintain good long-term cycle stability. But the preparation method significantly impacts the homogeneity of samples related to their redox properties and the content of Zr over 20%, which greatly changed the properties of ceria-zirconia solid solutions and caused their changing of crystalline symmetry from cubic to tetragonal. The samples prepared by citric acid solgel method are of more homogeneous particle sizes and higher specific surface areas than that by urea grind combustion method, which is benefit to the oxygen release rather than oxygen storage. The bulk oxygen amount migrated to surface increases with the increasing Zr content, however, the amount of lattice oxygen migration decreases when Zr content is over 20%. When Zr content is 20%, the differences of storage/release capacities from two different preparation methods are reduced at high temperature in the long-term loop reaction.
基金Supported by Shanxi Science and Technology Tackling Fund(No.20100311090)Shanxi Provincial Health Department Science and Technology Tackling Fund (No.2008034)
文摘OBJECTIVE:To analyze the constituents of volatile oils extracted from Yuan Zhi(Radix Polygalae),Shi Chang Pu(Acorus Tatarinowii),and a mixture of the two herbs.METHODS:The volatile oils were extracted using supercritical fluid extraction(SFE) with CO 2,and the constituents of the volatile oil extracts were analyzed by gas chromatography-mass spectrometry(GC-MS).The relative content of each component was calculated using peak area normalization.RESULTS:The optimized SFE conditions were 45 MPa at 35℃ for 2 h.Twenty-four compounds were identified in the extract from the Yuan Zhi(Radix Polygalae) and Shi Chang Pu(Acorus Tatarinowii) mixture,and six of these had relative contents >1.These compounds were 1,2-dimethoxy-4-(2-propenyl)-benzene;1,2,3-trimethoxy-5-(2-propenyl)-benzene;β-asarone;(Z,Z) 9,12-octadecadienoic acid;(Z) 6-octadecenoic acid;and ethyl oleate.Combination of the herbs increased the number of pharmacologically active substances in the extract and decreased the number of compounds with one benzene ring compared with the extracts from the individual herbs.CONCLUSION:These results indicate there is a synergistic relationship among the compounds in these herbs.
基金supported by the National Natural Science Foundation of China (Nos. 21006067, 21276170)the Shanxi Province Natural Science Foundation (Nos. 2010021008-1, 201101008-4)the National High-Tech Research and Development Program (863) of China (No. 2013AA065404E)
文摘Higher concentrations of Hg can be emitted from coal pyrolysis or gasification than from coal combustion, especially elemental Hg. Highly efficient Hg removal technology from coal-derived fuel gas is thus of great importance. Based on the very excellent Hg removal ability of Pd and the high adsorption abilities of activated carbon(AC) for H2 S and Hg, a series of Pd/AC sorbents was prepared by using pore volume impregnation, and their performance in capturing Hg and H2 S from coal-derived fuel gas was investigated using a laboratory-scale fixed-bed reactor. The effects of loading amount, reaction temperature and reaction atmosphere on Hg removal from coal-derived fuel gas were studied. The sorbents were characterized by N2 adsorption, X-ray diffraction(XRD) and X-ray photoelectron spectroscopy(XPS). The results indicated that the efficiency of Hg removal increased with the increasing of Pd loading amount, but the effective utilization rate of the active component Pd decreased significantly at the same time. High temperature had a negative influence on the Hg removal. The efficiency of Hg removal in the N2–H2S–H2–CO–Hg atmosphere(simulated coal gas) was higher than that in N2–H2S–Hg and N2–Hg atmospheres, which showed that H2 and CO, with their reducing capacity, could benefit promote the removal of Hg. The XPS results suggested that there were two different ways of capturing Hg over sorbents in N2–H2S–Hg and N2–Hg atmospheres.
基金the financial support of National Natural Science Foundation of China(Nos.U1910201,21878208,21961024)Shanxi Province Science Foundation for Key Program(No.201901D111001(ZD))+1 种基金Inner Mongolia Natural Science Foundation(No.2018JQ05)Inner Mongolia Autonomous Region Science&Technology Planning Project for Applied Technology Research and Development(No.2019GG261)。
文摘Hierarchical porous carbon(HPC)from bituminous coal was designed and synthesized through pyrolysis foaming and KOH activation.The obtained HPC(NCF-KOH)were characterized by a high specific surface area(S_(BET))of 3472.41 m^(2)/g,appropriate mesopores with V_(mes)/V_(total)of 57%,and a proper amount of surface oxygen content(10.03%).This NCF-KOH exhibited a high specific capacitance of 487 F/g at 1.0 A/g and a rate capability of 400 F/g at 50 A/g based on the three-electrode configuration.As an electrode for a symmetric capacitor,a specific capacitance of 299 F/g at 0.5 A/g was exhibited,and the specific capacitance retained 96%of the initial capacity at 5 A/g after 10,000 cycles.Furthermore,under the power density of 249.6 W/kg in 6 mol/L KOH,a high energy density of 10.34 Wh/kg was obtained.The excellent charge storage capability benefited from its interconnected hierarchical pore structure with high accessible surface area and the suitable amount of oxygen-containing functional groups.Thus,an effective strategy to synthesize HPC for high-performance supercapacitors serves as a promising way of converting coal into advanced carbon materials.
基金support of the National Basic Research Program of China(2005CB221203)the National Natural Science Foundation of China(Grant No.20976117)+1 种基金Shanxi Province Natural Science Foundation(2010011014-3)Shanxi Province Basic Conditions Platform for Science and Technology Project(2010091015).
文摘A series of iron-manganese-based sorbents were prepared by co-precipitation and physical mixing method,and used for H_(2)S removal from hot coal gas.The sulfidation tests were carried out in a fixed-bed reactor with space velocity of 2000 h^(-1)(STP).The results show that the suitable addition of manganese oxide in iron-based sorbent can decrease H_(2)S and COS concentration in exit before breakthrough due to its simultaneous reaction capability with H_(2)S and COS.Fe3O4 and MnO are the initial active components in iron-manganese-based sorbent,and FeO and Fe are active components formed by reduction during sulfidation.The crystal phases of iron affect obviously their desulfurization capacity.The reducibility of sorbent changes with the content of MnO in sorbent.S7F3M and S3F7M have bigger sulfur capacities(32.68 and 32.30 gS/100 g total active component),while S5F5M has smaller sulfur capacity(21.92 gS/100 g total active component).S7F3M sorbent has stable sulfidation performance in three sulfidation-regeneration cycles and no apparent structure degradation.The sulfidation performance of ironmanganese-based sorbent is also related with its specific surface area and pore volume.
基金Supported by the National Science and Technology Support Program of the Ministry of Science and Technology of the People's Republic of China (No.2011BAI07B05)Shanxi Science and Technology Tackling Fund (No.20100311090,20130313015-2)Department of Health of Shanxi province Tackling Fund (No.200834)
文摘OBJECTIVE: To study the effects of the drying processing in terms operational parameters on the bioactive constituents of six Yuanzhi(Radix Palygalae)samples across China.METHODS: Six Yuanzhi(Radix Palygalae) samples were investigated using thermogravimetry analysis. The heating courses were set in two ways: thetemperature-programmed process from room temperature to 150℃,and the constant-temperature course at 50℃, 70℃ and 90℃.RESULTS: The peak temperature of six Yuanzhi(Radix Palygalae) samples ranged from 78℃ to 88℃.The mass loss rate ofYuanzhi(Radix Palygalae) alcohol-soluble extract was significantly increased when heated at 90℃. Four types of bioactive ingredients were detected in volatile oils of Yuanzhi(Radix Palygalae) sample from Shanxi province by Gas Chromatography-mass spectrometry analysis. Fourier Transform Infrared Spectroscopy results showed that the drying temperature exerted a great influence on types and amount of ingredients of Yuanzhi(Radix Palygalae). The kinetic study showed that the constant-temperature drying process ofYuanzhi Radix Palygalae) samples could be well described by the Page Model, especially for the drying process at 50℃, in which R2and SD values were more than 0.98 and less than 0.04, respectively. The drying constant k of three Yuanzhi(Radix Palygalae) samples from Shanxi, Gansu and Shaanxi provinces in China was corresponding to the Arrhenius equation, and their activation energies were28.07, 25.38 and 21.48 kJ/mol, respectively.CONCLUSION: The drying process of Yuanzhi(Radix Palygalae) was very important for bioactive ingredients improvement in Yuanzhi(Radix Palygalae). Temperature was a thermodynamic property significantly affecting the process.
基金the financial support of the National Basic Research Program of China(Grant No.2005CB221203).
文摘In poly-generation and integrated gasificationcombined cycle(IGCC)systems for clean energy conversion,it is essential to remove impurities such as sulfur species from hot coal gases prior to entering the subsequent units.This paper provides a comprehensive review on previous studies on high temperature removal of hydrogen sulfide from high temperature coal gases using iron-based sorbents.A two-step desulphurization process for hot coal gas cleanup is highlighted,which is integrated with direct production of elemental sulfur during regeneration of ironbased sorbents in the primary desulphurization step.Different kinetic modeling approaches for sulfidation and regeneration were compared.Limited research on activated carbon supported sorbents was also briefly summarized.
