Abstract: The various slowly and rapidly pyrolyzed chars were prepared with Huainan coal and Guizhou coal at pyrolysis temperatures of 950℃～1400℃, and the evolvement behavior of carbon mincrystal and pore structure of coal chars was investigated during high temperature pyrolysis process. At the same time, the evolvement of pore structure of coal chars was studied. The content of carbon and hydrogen of slowly pyrolyzed chars (SPC) is obviously different from those of rapidly pyrolyzed chars (RPC). As the pyrolysis temperature increases, the carbon minicrystals of coal chars become more and more ordered. Besides, the ‘graphitization’ degree of SPC is larger than that of RPC. The micropore surface area and pore volume for RPC are obviously larger than those for SPC, indicating that the pores of RPC are much richer than those of RPC. In the initial gasification process of coal chars, the micropore surface area of coal chars decreases, while the micro- and meso-pore surface area of coal chars increases. In the end of coal char gasification process, the total surface area of coal chars decreases rapidly.
Abstract: Hydrogen-rich gas production from Chinese Xiaolongtan lignite was performed in a continuous supercritical water reactor with feeding of coal water slurry. The effects of KOH/coal weight ratio, temperature and pressure on carbon gasification efficiency, product distribution and yields of gas were investigated. At KOH/coal weight ratio of 4.1% (600℃, 25MPa), carbon gasification efficiency reaches to 31.5%. The content of hydrogen in gas is 38.5% and its yield reaches to 239.1mL/(g daf coal). There is a notable increase in the yield of hydrogen with the elevation of reaction temperature. The yield of hydrogen increases from 53.0mL/(g daf coal) to 287.8mL/(g daf coal) when temperature increases from 500℃ to 650℃. The catalytic performance of KOH is distinct at higher temperature. The increase of pressure also has positive impact on yield of hydrogen.
The trace element contents of 5﹟coal samples from Weibei before and after acid treatment has been compared. The result shows that 44 trace elements in the coal seam, according to acid removal rate which is quantitative to characterize element affinity, can be divided into 5 categories. There is a very clear distribution in the periodic table of elements. Type I is most easily acid removed and is located mainly at IA and IIA in the periodic table of elements. They belong to s area according to their electronic configurations. Type II is easier to acid removal. Type III is less prone to acid removal, which is situated at IIIB, VB, VIB and VIIIB. It belongs to d area and left part of f area in the periodic table of elements. Type IV is difficult to be removed by acid, which is situated at IVA and VA. It belongs to p area and f central area in the periodic table elements. Type V is most difficult for acid removal and is located at IIB, IIIB and IVB. It belongs to the first half of d area, ds area and right part of f area in the periodic table of elements. The acid removal rate of trace elements in coal, along the direction of vertical, horizontal and diagonal in the periodic table of elements, has some correlations. Type II trace elements can not be determined in the periodic table of elements temporarily because of its small number and scatteration in this study.
Abstract: The content of trace elements such as Cd, Se in coal and coking products including solid-phase product (coke) and liquid-phase products (tar and ammonia) were determined. The contents of trace elements in coals with different ranks were compared and the distribution of Cd, Se during coal coking was discussed. It is shown that the content of Cd decreases with increasing coal rank. The content of Se in fat-coal is lower than that in gas coal, however, its content in coking coal is close to that in lean coal. Coking in a simulated temperature of 1000℃, 48% of Cd and 45% of Se remain in the coke; 7% of Cd and 2% of Se are transferred into the ammonia; 15% of Cd and 12% of Se are partitioned into the tar. Through the mass balance it is found that 30% of the Cd and 41% of the Se could potentially exist in gas phase.
Abstract: The co-slurryability of water hyacinth and Shenfu coal was investigated with 2 dispersants, methyl-naphthalene sulfonate sodium formaldehyde condensate (MF) and modified sodium lignosulphonate (B1). The results show that when mixing 19.16g water hyacinth into 100 g coal, the apparent viscosity of coal-hyacinth slurry (60%) was 1154mPa·s using MF as dispersant; and it decreased to 999mPa·s while water hyacinth is modified by Fe2(SO4)3.Using B1 as dispersant the apparent viscosity of coalhyacinth slurry (60%) decreased slightly. Fe2(SO4)3 reduced the number of hydrogen bonding oxygen-containing functional groups, and increased the content of free water in hyacinth. The stability of coal-water slurry is improved by adding water hyacinth, and the sedimentation time increases from 2h to 60h. Fe2(SO4)3 can further improve the stability of coal-water slurry with sedimentation time up to 88h. The hydrophilic oxygen-containing functional groups and cellulose in water hyacinth play the key role in improving the stability of coal water slurry.
Abstract: To understand a novel process for preparation of calcium carbide (CaC2) from pulverized feed stocks, the reactions between a coke and various calcium compounds including calcium carbonate (CaCO3), calcium hydroxide (Ca(OH)2), residue from the reaction of CaC2 with water, CaSO4 (the main compound in FGD residue) and calcium oxide (CaO) were examined in a TG-MS system up to 1850℃. The results show that all the calcium compounds, except CaSO4, can be used directly for CaC2 preparation, which starts at about 1450℃ and peaks at about 1740℃. The H2O and CO2 generated from the decomposition of the calcium compounds have little effect on CaC2 formation. At about 920℃ CaSO4 reacts with coke to form CaS, which does not react further with the coke in the temperature rang studied.
Abstract: Effect of ionic liquids (ILs) as media for the decomposition of formic acid in the presence of organic amine was investigated, and this activity was observed to be markedly promoted by the addition of ILs, especially for BMImCl. Based on this finding and to avoid volatile organic amine, a series of amine-functionalized ILs were further designed and prepared as both reaction media and cocatalyst for homogeneous decomposition of formic acid. Among the ILs investigated, i-Pr2NEMImCl-HCOONa system exhibited high activity (TOF > 600mol/mol/h). This efficient and green method to produce hydrogen by formic acid decomposition has practical potentiality.
Abstract: The pyrolysis of rice straw and sawdust under microwave irradiation was performed with ionic liquids (ILs) 1-butyl-3-methylimidazolium chloride and 1-butyl-3-methylimidazolium tetrafluoroborate as catalysts. With microwave heating for 20min, the bio-oil yield from rice straw reached 38% and that from sawdust reached 34%. The effects of microwave heating time, microwave power, and IL dosage on bio-oil yields were discussed. The chemical components in bio-oil were analyzed by gas chromatography-mass spectroscopy technique. The main components in bio-oil are furfural, acetic acid, and 1-hydroxy-2-butanone, and their contents mainly depend on the source of biomass and the type of IL used in pyrolysis.
Abstract: Upgradation of bio-oil before utilization is desirable to obtain high grade fuel because of its drawbacks like high viscosity, low heating value, poor stability and high corrosiveness. Organic acids in bio-oils can be converted to their corresponding esters by catalytic esterification and this greatly improved quality of bio-oils. We selected 732 and NKC-9 type ion exchanger resins as esterification catalysts for upgrading bio-oil. The catalytic activity was first investigated by model reaction first. The esterification of bio-oil with methanol was conducted in a batch reactor. Acid numbers of upgraded bio-oil on 732 resin and NKC-9 resin were lowered by 88.54% and 85.95% respectively, which represents the conversion of organic acids to neutral esters; the heating values increased by 32.26% and 31.64% respectively; the H2O contents decreased by 27.74% and 30.87% respectively; the densities were lowered by 21.77% for both and the viscosities fell by approximately 97%. A fixed bed reactor was used for continuous catalytic esterification of bio-oil by 732 resin and the acid number remarkably decreased by 92.61％. The accelerated ageing test showed improvement of stability and the aluminum strip corrosion test showed reduced corrosion rate of bio-oil after upgradation.
Abstract: Liaohe heavy oil vacuum residuum was separated into the light de-asphalted oil (LDAO), heavy de-asphalted oil (HDAO) and de-oiled asphalt (DOA) in a continuous de-asphalting device by deasphalting under supercritical conditions with pentane as solvent. The effects of pressure (4.0MPa～7.0MPa) and temperature (155℃～170℃) on the yield and properties of the de-asphalted oil were investigated. The Conradson carbon residue (CCR) and removal rates of N and Ni elements were correlated with that of supercritical fluid extraction fractions (SFEF). With the increase of pressure and the decrease of temperature, the total yield of deasphalted oil (DAO) is increased; meanwhile, the contents of CCR and elements like S, N, Ni and V in LDAO and HDAO are also increased. When the total yield of DAO is 74.23% (the yields of LDAO and HDAO are 57.68% and 16.55%, respectively), the removal rates of Ca, Ni, CCR, N and S are 92.75%, 74.50%, 62.13%, 40.17% and 24.10%, respectively; the removal rates for DAO correlate well with that for the SFEF fractions. The properties of DAO can be correlated with the extent of deasphalting and the properties of Liaohe heavy oil vacuum residuum feed.
Abstract: ZnSi/HZSM-5 aromatization catalyst was prepared by modification with silicon on the outer surface and zinc on the inner surface; its aromatization performance and resistance to carbon deposition were investigated in a laboratory fixed reactor with the full range FCC gasoline as the feed. The modification mechanism was also discussed. The crystal phase, pore structure, acidity of the modified catalysts and the coke formed during the reaction were characterized by means of XRD, BET surface area, Py-IR and elemental analyses. The modified ZnSi/HZSM-5 aromatization catalyst exhibits a superior activity, stability and performance in reducing olefin content of FCC gasoline; under the conditions of 500℃, 1.5MPa and a space velocity of 3.0h-1, the mass fractions of olefins and aromatics in the upgraded gasoline are 21.75% and 27.32%, respectively.
Abstract: ZSM-5 catalysts were modified with Ga and Zn by using impregnation and hydrothermal methods to obtain zeolite catalysts with different acidities. XRD, SEM, NH3-TPD and XPS were used to characterize the effects of the modification components (Ga and Zn) and methods (impregnation and hydrothermal methods) on the pore structure, skeletal structure and surface acidity of the resultant catalysts. The performances of the Ga and Zn modified catalysts for alkene aromatization were evaluated with propylene as a model compound. The results indicated that Ga and Zn modification has little influence on the morphology of catalysts particles, but it obviously changes the surface acidity and alkene aromatization reactivity of the catalysts. Zn modification reduces the acidity of ZSM-5 catalyst, while the effect of Ga modification on the catalyst acidity depends on the Ga addition methods. Ga introduced through impregnation slightly reduces the strong acid sites, while Ga introduced via hydrothermal method apparently increases the intensity of both weak and strong acid sites. Ga and Zn modifications are able to increase the aromatization activity and the aromatics selectivity, and to suppress the carbon deposition.
Abstract: A series of Zr-containing SBA-15 mesoporous materials with different zirconium contents were synthesized via adding zirconium nitrate into SBA-15 synthesis solution and adjusting the pH value to 4.0～5.0 with ammonia water. The materials were characterized by XRD, N2- physisorption, SEM, TEMEDS, ICP, FT-IR, and UV-vis DRS. The results indicated that all Zr-SBA-15 samples were endowed with special hollow spherical morphology, nanometer pore structure, high surface area, and improved surface acidity. The formation of hollow mesoporous microspheres could be immediately involved with pH-adjusting treatment and heteroatoms introduction. Compared with the unmodified SBA-15, Zr-SBA-15 displays orderly mesoporous structure and high loading efficiency of heteroatoms inside the siliceous matrix, which remarkably improves the surface acidity and catalytic property. Meanwhile, the performance of these catalyst materials in methanol dehydration is also related with the alteration of surface acidity caused by the introduction of zirconium.
Abstract: The effect of intraparticle diffusion on the performance of Co/ZrO2 F-T catalyst was investigated. According to the change of apparent activation energy, the reaction pathway might vary while changing the extent of diffusion limitation. After catalysts were activated, the inner pores would be filled with F-T product gradually. The ratio of gaseous olefin to paraffin followed the “U” type trend. The selectivity to CH4 increased with the increase of GHSV. And the ratio of gaseous olefin to paraffin also increased slightly with the increase of GHSV due to the intraparticle diffusion limitation.
Abstract: The un-supported Ni-Mo-Al2O3 catalysts were prepared using the thermal decomposition method with nitrate hexahydrate and ammonium paramolybdate as precursors. The evaluation of hydrodeoxygenation activity of the catalysts was conducted in a continuous flow fixed-bed reactor, using the acetic acid and the phenol as probe compound. The catalysts were characterized using specific surface area (BET), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectrdmeter (EDS). The effects of calcination temperature on the catalyst crystalline structure, element relative content and activity were investigated emphatically. The results show that the surface area of the catalysts increases and the crystallization degree of catalysts were improved with increasing the calcination temperature. The Ni/Mo/Al radio on surface of the catalysts calcined at 550℃ was optimal, and the catalyst exhibited the highest hydrodeoxygenation activity, and the deoxygenation percentage of the acetic acid was 96.0% at 250℃, 0.4MPa and the deoxygenationa percentage of the phenol was 96.8% at 200℃, 0.3MPa.
Abstract: Synthesis of anisole with DMC and phenol over SiO2 supported K2CO3, KBr, and KF catalyst was studied under continuous condition. Effects of the reaction conditions such as reaction temperature, reaction space velocity, ratio of reactants and catalyst loading amount, were investigated. The optimized reaction conditions were found for KF/SiO2. The ratio of DMC to phenol is 2∶1(mol ratio), MHSV is 2h-1 and reaction temperature is at 250℃, yield of anisole is as high as 93.93%, and anisole selectivity is high to 98.19%. And the catalyst activity was still very high after 16h of reaction. Therefore, the new reaction technology introduced in the present study is a practical environmentally benign anisole synthesis process.
Abstract: A special-shaped tubular cathode was prepared by using graphite-doped mesocarbon microbeads (MCMB/G) through dip coating the gas diffusion layer and catalyst layer and wrapping the sintering tube with the Nafion membrane subsequently. The sol-gel flux phase was prepared by sol-gel technology. The impedance of the special-shaped direct methanol fuel cell with sol-gel flux phase was investigated; the effects of tube wall thickness, gas diffusion layer loading, working temperature, and sol viscosity on the cell polarization performance were examined. The results showed that the impedance of the special-shaped cell was much higher than that of the traditional flat electrode ; however, an obvious decrease in impedance was observed after activation. The cell performance improved with the decrease in sol viscosity and with the increase in working temperature. The cell performs well when the wall thickness is 1.3mm and the gas diffusion layer loading is 3.5mg/cm2.
Abstract: The performance of H2S solid oxide fuel cell with yttria-stabilized zirconia (YSZ) oxygen ion-conducting membrane was investigated. The binary metal composite MoS2 anode catalysts (with doping NiS, electrolyte YSZ, Ag powder and starch), the composite NiO cathode catalysts (with admixing electrolyte YSZ, Ag powder and starch), and the membrane electrode assembly (MEA) were prepared. The YSZ and MEA were characterized by using scanning electron microscope (SEM). The performance of several electrode catalysts was compared and the influence of operating temperature on the cell performance was examined. The results demonstrated that the binary metal composite MoS2/NiS anode catalysts work more stably than Pt and single metal MoS2 ones in H2S stream and the performance of composite NiO cathode catalysts is superior to that of Pt. The addition of Ag powder into the electrodes can significantly increase their electrical conductivity. The overpotentials of the composite MoS2 and NiO catalysts are smaller than that of Pt and the polarization of anode is smaller than that of cathode. With the increase of the cell temperature, the current and power densities are increased due to the elevation of the electrical conductivity of membrane and electrochemical reaction rate of fuel cell, which leads a better cell electrochemical performance. For the single fuel cell with the configuration of “H2S, (composite MoS2 anode)/YSZ membrane/(composite NiO cathode), air” operated under 101.13kPa and the temperatures of 750℃, 800℃, 850℃ and 900℃, the maximum currents obtained are 120mA/cm2, 240mA/cm2, 560mA/cm2 and 890mA/cm2 and the power density are 30mW/cm2, 70mW/cm2, 155mW/cm2 and 295mW/cm2, respectively.
Abstract: The properties of gasification for three kinds of sewage sludges with different moisture contents are studied in an external heated downdraft reactor under a stable air flux of 0.05m3/h and a constant gasification temperature of 800℃. The results show that the contents of CO2, CH4 and H2 in gas, lower heating value (LHV) of gas and aqueous yield increase with increasing moisture content, while content of CO and tar yield decrease. Sludge anaerobic digestion process increases the contents of CO, CH4, H2 and CmHn in gas and reduces the quality of gas. The anaerobic process in wastewater treatment can improve the quality of gas. The quality of gas produced by gasification of anaerobic digestion sludge from A2/O process is higher than that from activated sludge process. With increasing moisture content in sludge, the difference in the contents of CO, CO2 and H2 in the gas produced by both anaerobic digestion sludge gasification is gradually increased, and the difference in the contents of CO2 and H2 produced by the gasification of digested and undigested sludges from the same A2/O process is also increased, while the difference in CO content is gradually reduced.
Abstract: The melting experiment of fly ash was conducted in a self-designed swirling melting furnace. The melting characteristics of fly ash were systematically investigated in terms of morphology, properties of heavy metals and leaching behavior. The experimental results show that the slag is black, frail and rigid by swirling melting. The fixation rates of nickel and chromium achieve the maximal value above 95%. The low boiling point heavy metals are volatilized into flue gas or on the particles of melting fly ashes. The fixation rate of cadmium is only 21%, and the fixation rates of lead and zinc reach above 42% in the glassy slag. The fixation rates of copper and arsenic are 37% and 18%, respectively. The leaching rates of heavy metals in glassy slag are much lower than those of raw fly ash, which are below the (EPA) regulatory limit values.
Abstract: A novel method for the deep desulphurization of fuel products was investigated by using the metal organic framework material MOF-5 as an adsorbent. MOF-5 was synthesized hydrothermally and its structure was characterized by means of XRD, SEM and N2 adsorption. The desulphurization performance of MOF-5 was tested in terms of breakthrough curves with the simulated oils at room temperature. The results showed that the adsorbent MOF-5 possesses quite large sulfur capacity, even larger than those reported previously in literature. The adsorbent breakthrough capacity and saturation capacity for sulfur component were 0.90% and 1.92% in the aliphatic oil, and 0.64% and 1.72% in the aromatic oil, respectively. The negative effect of moisture on the desulphurization performance was eliminated by packing it with the activated carbon adsorbent together, which provides a new way for the development of the adsorptive desulphurization process.
Abstract: The operation performance of a membrane absorption-regeneration circulatory setup were investigated with a complex aqueous absorbent of N-methyldiethanolamine (MDEA) + piperazine (PZ) for CO2 capture. Effects of gas and liquid flow rates, absorbent concentrations and regeneration voltages on CO2 capture efficiency and mass transfer flux were studied. An optimal operation condition was determined by orthogonal optimization design. The results showed that, effects of gas flow rates on the capture efficiency was remarkably larger than that of liquid flow rates. The effects of the increase of the gas flow rates on the mass transfer flux was inconspicuous. The mass transfer fluxes rapidly increaseed with the increase of the absorbent concentrations. However, the flux no longer increased as the absorbent concentration reached a certain value. The optimum operation condition obtained through the orthogonal optimization design was the liquid flow rate in 110mL/min, the gas flowrate in 0.65L/min, absorbent concentration in 2.5mol/L and regeneration voltage in 210V. Here, the capture efficiency was higher than 95% and the mass transfer flux kept in 5.86×10-4mol/(m2·s).
Abstract: A new type of hydrogen-generation reactor with porous ceramics arranged regularly inside and a Swiss-roll heat exchanger outside was designed. The fuel rich combustion experiment was investigated with the mixture of methane and air at an equivalence ratio ranging from 1.25 to 2.50 and a total flow rate ranging from 60L/min to 120L/min. The combustion characteristics of autothermal reforming were studied. The experimental results show that it can realize the self-maintenance combustion and come to the self-stabilization fast in the fuel-rich conditions. The preheating effects of Swiss-roll structure and the heat storage of porous media can raise the reaction temperature to more than 1600K, and realize the superadiabatic fuel rich combustion. The hydrogen production rate and energy utilization which change inconsistently with the equivalence ratio at a fixed total flow rate range can reach 30%~57% and 50%~84%, respectively. The maximum molar fraction of hydrogen, hydrogen production rate and energy utilization are up to 22%, 57%, and 68%, respectively at an equivalence ratio of 2.0.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
