Abstract: Conversion of coaltar pitch in supercritical water (SCW) was researched using a batch reactor. The effects of temperature (400℃~480℃), pressure (25MPa~40MPa), and residence time (1min~80min) on product composition were investigated. When compared with pyrolysis under N2 atmosphere, the conversion of asphaltene to maltene was enhanced, whereas, the formation of gas and char were restrained in SCW. Moreover the yields of high value chemicals were higher than those obtained via pyrolysis. The results suggest that SCW promotes the decomposition of coaltar pitch into maltene and enhances the yields of high value chemicals. It is also observed that asphaltene is the main active component and it is converted to maltene, gas, and char in SCW. High temperature promotes the reactions of both asphaltene to light components and the formation of char. The results indicate that temperature appears to be the important parameter for coal tar pitch conversion, whereas, the effects of pressure and time are less significant.
Abstract: The effects of temperatures and atmospheres on sulfur transformation during pyrolysis of Zunyi (ZY) raw coal and its chars were investigated by AP-TPR-MS combined with chemical analysis. The results show that stable organic sulfur is the main sulfur form in ZY coal. Pyrite can be removed under all the atmospheres in the tests, except for nitrogen at 500 ℃. 1% O2-N2 atmosphere has strong reactivity to remove the stable organic sulfur in ZY coal, especially at 700 ℃. Under 1% O2-N2 atmosphere, not only a part of stable organic sulfurs can be decomposed, but also more stable organic sulfurcontaining structure can be broken down into less stable one. Syngas and 1% O2-N2 atmospheres have almost the same effect as hydrogen on sulfur transformation at 700 ℃.
Abstract: A series of SO4 2－/ZrO2 solid acid catalysts were prepared by precipitationimpregnation. Its acidity and catalytic property on the hydroliquefaction of coal were investigated by NH3-TPD and FT-IR analysis. XRD, BET and TG/DTA measurements also were used to characterize the structure of SO4 2－/ZrO2 solid acid. The results indicate that the intensity of acid site on SO4 2－/ZrO2 solid acid is nonhomogenous and successive distribution. The acid site of SO4 2－/ZrO2 solid acid is mainly mediumstronger acid. The catalysis of SO4 2－/ZrO2 solid acid on the hydroliquefaction of coal exhibits mostly its catalytic activity on pyrolysis reaction. The stronger acid site shows higher catalytic activity. Higher calcinations temperature is advantageous to improve the intensity of acid site and the proportion of strong acid site, and increase the conversion of coal. SO4 2－/ZrO2 solid acid calcinated for 3h at 650℃ shows the best catalytic activity and obtains 76.77% of conversion.
Abstract: The effects of alkali and alkaline earth metals (K, Ca) on the steam gasification of a lignite char were investigated with a fixedbed reactor. The gasification reactivity of the chars with different catalyst loadings was examined. The crystallite constituents in the char and its gasification residue were identified by Xray diffraction (XRD). The morphology of the chars and the catalyst dispersion were analyzed by scanning electron microscope (SEM) equipped with an energydispersive Xray analyzer (EDX). The results show that the catalytic effect of potassium is higher than that of calcium. The reactivity of chars increase linearly with catalyst loadings up to a loading saturation level (LSL) which is about 10% for both K and Ca. K and Ca were identified by EDX on the surface of chars produced from the raw coal samples loaded with potassium carbonate and calcium nitrate respectively. Gehlenite is the major constituent in the gasification residue of raw char. Gehlenite and rankinite are the major crystallites from chars loaded with potassium carbonate and their residues, but the crystallite with K is not detected by XRD. Large amount of calcium oxide attached to the char surface and the catalyst dispersion deteriorates due to agglomeration when the calcium loading is above the LSL. In addition to gehlenite and larnite, calcium oxide and calcium hydroxide uncontaminated by mineral matter are detected in the gasification residue from char loaded with 10% calcium.
Abstract: By applying the Ontario Hydro Method (OHM) and the US EPA standard methods, the sampling of mercury in the flue gas before and after fabric filter (FF)/electrostatic precipitator (ESP) located at five coalfired power plants was carried out on site and various mercury speciation such as Hg0, Hg2+, and HgP in flue gas were analyzed. The solid samples, such as coal, bottom ash, and FF/ESP ash, were analyzed by DMA80 based on EPA Method 7473. According to mercury balance, the mercury speciation and its distribution in different locations downstream the flue gas were obtained. The mercury removal efficiency of coalfired power plants 1 and 2 installed FF is higher than 80% and 20%, respectively, while that of plants 3, 4, and 5 installed ESP is around 6%, 20%, and 4%, respectively. It can be concluded that the performance of mercury removal in FF is better than ESP, and then various factors have important effects on the mercury removal.
Abstract: A simple and practical heat flux probe was designed according to one dimension steady state heat conduction law. Simulation on ash deposition process was made with heat flux probe when four representative fuels, including Shenmu coal, Huangling coal, Xinwen CWS and black liquor coal slurry, were burned in 0.25MW test furnace. Heat flux variation and ash deposition characteristic was investigated for the fuels. The results indicate that ash probe can be applied well for simulating formation of ash deposition of different fuels. The simulation results are corresponding with the practical case. Ash depositing rate and heat flux decay rate depend on fuel characteristic mainly, meanwhile influenced by flue temperature. By analyzing apparent physical characteristic, microcosmic structure, elements composition and mineral phase of ash in probe, the result reveals ash deposition mechanism of four typical fuels is different. The content of Na, K and S in black liquor coal slurry ash is higher than else, and its dominant phase is nepheline and thenardite, with high Na and low fusing temperature. While Huangling coal ash deposited in probe is rich in Fe, Ca. Enrichment and deposition of Fe is the principal factor in ash forming process when Xinwen CWS is burned. Among the fuels tested, the slagging tendency of black liquor coal slurry and Huangling coal is stronger than that of Shenmu coal and CWS.
Abstract: Activated coke (AC) supported V2O5 (V2O5/AC) is very effective for simultaneous removal of SO2 and NO from flue gas at around 200℃. The SO2 removal is accomplished by oxidation of SO2 into SO3 and then formation of sulfuric acid storing within the pores of AC. Regeneration of the used V2O5/AC is important for continuous operation. It can be achieved in the presence of NH3 at temperatures lower than that required by AC under an inert atmosphere. SO2 desorbed from the used V2O5/AC can be recovered to solid ammoniumsulfur salts through reactions between SO2 and NH3 upon cooling of the regeneration effluent to temperatures below 80℃. Coupling of the regeneration and the ammoniumsulfur salts formation processes by recycling the effluent gas back to the regeneration reactor make the regeneration and sulfur recovery very efficient. This work studies the effect of regeneration conditions on desorption of SO2, recovery of sulfur, and SO2 and NO removal activities in the subsequent operation. Regeneration conditions tested include the amounts of NH3 been injected, regeneration temperature, regeneration time and the recycle rates of the effluent gas. The results show that the regeneration temperature and time affect the desorption of SO2 and subsequent SO2 and NO removal activities. Amounts of NH3 injected affect sulfur recovery and SO2 and NO removal activities, but recycle rate of the effluent gas has little effect on all these parameters.
Abstract: NanoNiO particles were prepared by using the homogeneous precipitation method, and characterized by using Xray Diffraction (XRD), BET and transmission electronic microscope (TEM). The prepared nanoNiO particles were found to be spherical in shape, could be well dispersed, and demonstrated weak agglomeration. They generally had high purity and a fine crystal phase of cubic syngony with a mean size of ~7.5nm and specific surface area of 187.98m2/g. Meanwhile, evaluation of the catalytic activity of developed nanoNiO particles in pyrolyzing cellulose was carried out in comparison with that of microNiO, in the same conditions, using TGA. The results indicated that the activation energy in the presence of microNiO and nanoNiO reduced by 12.24kJ/mol and 22.42kJ/mol, respectively, in comparison with that of pure cellulose pyrolysis. This resulted in the initial temperatures of cellulose decomposition being 10℃ and 19℃ lower than that of pure cellulose, and the final char yield was further decreased. Compared to the microNiO, nanoNiO particles demonstrated an even superior activity.
Abstract: Thermochemical reduction of magnesium sulphate with npentane was carried out in an autoclave in the presence of water at high temperature and pressure to simulate the origination of organic sulfur compounds in petroleum from thermochemical sulphate reduction (TSR). The products of 3 phases (gas, oil, and solid) were analyzed by some advanced analytical methods including gas chromatography, microcoulometry, FTIR, and Xray diffraction. The results show that the TSR reaction occurred at 425℃~525℃ with MgO, C, H2S, CO2, and a series of organic sulfur compounds such as mercaptans, sulfoethers, and thiophenes as the main products. The reaction kinetics was studied and the calculated activation energy is 58.0kJ/mol.
Abstract: The properties of products from the pilot scale residue hydrodemetalization, hydrodesulfur and hydrodenitrogen tests were characterized. The result showed that the contents of sulfur, nitrogen, carbon residue, nickel and vanadium in products were reduced through above mentioned residue hydrotreating. The total removal rates of sulfur, nitrogen, carbon residue, nickel and vanadium were 84.9%, 51.3%, 62.8%, 84.8% and 94.0%, respectively. The composition distributions of the produced fractions had been changed. The content of saturate fraction increased, and those of aromatic, resin and asphaltene fractions decreased. The removal rates of resin and asphaltene fractions were 57.5% and 73.3%, respectively. The average structural parameters of factions were calculated based on proton nuclear magnetic resonance spectroscopy. The aromatic ring number and cycle ring number of structure unit of aromatic and resin fractions decreased. The fractions of aromatic carbon (fA), cycloparaffinic carbon (fN) and paraffinic carbon (fP) kept the same. The fA of asphaltene fraction increased, and the fN and fP of that decreased. The same fractions from different residue hydrotreating products were similar in structure, but the different fractions had quite distinct difference.
Abstract: The ability to stabilize asphaltene of DBSA, DP and DAL as the asphaltene dispersants in toluene/heptane solution was investigated by UV-Vis spectrum. A study of the dispersion and aggregation of asphaltene with different asphaltene dispersants was performed with a capillary tube viscosimeter. The aggregation number of the asphattene was determmed. The results showed that the dispersants could stabilize asphaltene in toluene solution, increased the asphaltene amount in solution. The effectiveness of these dispersants followed the order: DBSA>DP>DAL. It was found that the three asphaltene dispersants had the similar effect on the asphaltene aggregation. DBSA had the best effect on the asphaltene aggregation and the relative viscosity was increased with the addition. The aggregation number of asphaltene in toluene was decreased by addition of DBSA, DP and DAL. The retardation of asphaltene aggregation was found to be in the order: DBSA>DP>DAL. This order was matched by the acidity of these dispersants.
Abstract: Onestep synthesis of dimethyl ether (DME) from H2/CO was studied in a fixed bed reactor over hybrid catalyst CuOZnOAl2O3/γAl2O3HZSM5. The physicalchemical properties of the catalysts were also studied by means of H2TPR, XRD, TPO and N2O chemisorption. The results showed that in the process of catalyst deactivation, surface area of metallic Cu decreased greatly, but kept nearly constant TOF and selectivity to DME. Temperatureprogrammed oxidation (TPO) of the deactivated catalysts did not show significant O2 consumption, indicating that the deactivation was mainly caused by the sintering and conglomeration of Cu particles rather than carbon deposition or acidity loss. It was found that lower temperature, and N2/H2/CO/CO2 as feed gas could inhibit sintering deactivation. According to the experiment of the catalyst regenerated by means of redox cycle, Cu crystalline was redispersed and more than 75% activity was restored.
Abstract: The bifunctional catalysts for onestep DME synthesis were prepared by mixing JC207 catalyst and HZSM5 zeolites modified by MgO、CaO、ZnO,respectively. The evaluation of catalytic activity was conducted in a fixedbed reactor. Results show that Brostead acid site(strong acid sites) shifted to Lewis acid site (Weak acid sites) when the proper basic oxide was used to modify zeolite. Weak and less strong acid sites on the HZSM5 zeolite were activitive sites for the formation of DME whereas strong acid sites for by products such as hydrocarbons. Consequently, the selectivity of CO2 and hydrocarbons decreased over modified HZSM5 zeolite, especially over the zeolite modified by CaO.
Abstract: Selfmade experiment equipment for reforming hydrogen was developed. The equipment was set up to produce hydrogenrich gas from partial oxidation of DME. The effects of temperature, air/DME ratio, DME inlet velocity, mass of catalyst and inner diameter of reformer tube on partial oxidation of DME were investigated. At atmospheric pressure, when the temperature increased from 300℃ to 500℃, both DME conversion and H2 yield increased. The maximum of DME conversion was near to 100%, and the maximum of H2 yield was about 95%. In the product gas, the concentration of H2, CO and CH4 increased, but the concentration of CO2 and DME decreased. When air/DME ratio increased from 0.5 to 3.0, both DME conversion and H2 yield increased, and the concentration of H2 and CO in the product gas increased first and then reduced. When increasing DME inlet velocity, DME conversion and H2 yield and the concentration of H2 and CO in the product gas all reduced. Increasing the amount of the catalyst and reducing the inner diameter of the reformer tube increased DME conversion and H2 yield.
Abstract: The ceriabased complex oxides oxygen carriers (Ce-M-O, M＝Fe、Mn、Cu ) were prepared by coprecipitation method and their characterizations were studied by means of Xray diffraction (XRD).The reactions between methane and lattice oxygen over the complex oxides were investigated. The Ce-M-O oxygen carriers were regenerated by air oxidation at different reaction times and temperatures, and then the catalytic performances of oxygen carriers for partial oxidation of methane to syngas using lattice oxygen were investigated. The results showed that the Ce-Fe-O sample consisted of single crystal phase and its lattice oxygen was found to be suitable for partial oxidation methane to synthesis gas. There were two kinds of oxygen species in the fresh Ce-Fe-O solid solution. The stronger oxygen species was responsible for the complete oxidation of methane. Methane could be selectively oxidized to CO and H2 by the weaker oxygen specie (bulk lattice oxygen) at a higher temperature, then the lost bulk lattice oxygen could be selectively supplemented by air reoxidation at appropriate reaction conditions. Using the oxygen carrier which was regenerated at 850℃ for 7min, the selectivity of CO and H2 could reach 96.68% and 97.56% respectively and the value of H2/CO mol ratio in syngas was 2.02. In the absence of gas phase oxygen, it is possible to generate syngas using the lattice oxygen of the Ce-Fe-O to react with methane following the redox mechanism.
Abstract: Molybdenum carbide catalysts were prepared through temperatureprogrammed carburization of molybdenum trioxide with CH4/H2 gas mixture and characterized by XRD, BET, SEM, and XPS. The hydrodenitrogenation (HDN) performance of the molybdenum carbide catalyst was evaluated by using 5% pyridine/cyclohexane as a model reactant. The β-Mo2C prepared (carburized at 675℃) is in high purity with an average dimension of about 3.9 μm; its BET surface area is 10.7m2/g, which is 2.7 times higher than that of MoO3. Over Mo2C, pyridine HDN conversion reaches 86.30% under 340℃, 3.0MPa, and a space velocity 8h－1, which is about 8 percentages higher than that over MoS2. The optimal carburizing conditions for preparing Mo2C are around 675℃ with a CH4/H2 gas velocity of about 1.8×104h－1. Further increase of carburizing temperature may result in a decrease of the BET surface area of Mo2C and an increase of free carbon content deposited on the catalyst surface, which can then decrease the HDN activity of Mo2C.
Abstract: A series of vanadiumbased catalysts with SBA-15 as support were prepared by incipient wetness impregnation and characterized by XRD, BET, TPR, UV-Vis and NH3-TPD. The reaction of toluene oxidation over VOx/SBA15 was carried out in a fixedbed reactor under the conditions of 380℃~520℃, 0.15MPa, n(N2)/n(O2)/n(toluene) = 40/10/1, GHSV=600h－1. The results showed that there is an optimal vanadium loading to get highest benzaldehyde selectivity. Vanadium species existed mainly in the form of isolated and polymeric vanadium species at low vanadium loadings; increasing vanadium loadings would cause the formation of V2O5 crystalline. Isolated polymeric vanadium species were shown to be active in partial oxidation of toluene to benzaldehyde, whereas polymeric vanadium species, especially V2O5 crystalline, reduce greatly the selectivity of benzaldehyde in toluene oxidation. A better dispersion of vanadium species over VOx/SBA-15 surface was observed than those over VOx/MCM-41 and VOx/SiO2, this may contribute to its higher benzaldehyde selectivity in toluene oxidation.
Abstract: High concentration of H2 with a low concentration of CO and CO2 can be produced by the sorptionenhanced methane steam reforming with the CO2 sorbent addition. A mathematic model for the sorption enhanced methane steam reforming considering the activity loss of Cabased sorbents was developed and verified by the experimental data. The effect of the activity decay of three Cabased sorbents on the process of hydrogen production was explored by model calculation. The results indicate that the breakthrough time for high concentration of hydrogen production reduces rapidly with the cycle numbers increasing for a limestone sorbent, while the breakthrough time decreases gradually for a dolomite sorbent. The effective cycle umber of CaO/Ca12Al14O33 sorbent is far more than that of dolomite and limestone.
Abstract: An experimental study of the influence of pressure on Umf and bed expansion height by the photographing with a camera was carried out in a fluidized bed of 60mm i.d.in the range of operating absolute pressure 0.1MPa~1.5MPa with two kinds of different size particles . Experimental results indicate that for the polystyrene(Ps) particle with a larger size， Umf changes with p-0.3, and for the sand particle with a smaller size， Umf changes with p-0.21. An empirical equation about Umf is proposed based on the experimental data: Umf=μdp ρg｛［(34.15)2+0.05916×dp3 ρg( ρs- ρg)gμ2］12-34.15｝ It is found that the bed expansion height increases with the increasing of gas velocity, and increases with pressure for fixed value of UUmf, when the pressure exceeds 0.7MPa, the influence of pressure on the bed expansion height is weakened. For the polystyrene(Ps) particle, UUmf decreases with the increasing of pressure for fixed value of H/Hmf . When H/Hmf＝1.4～1.6，UUmf varies with p-0.52～p-0.58.
Abstract: Esterification of oleic acid in supercritical methanol was investigated; the effects of operation parameters such as reaction temperature, reaction time and molar ratio of methanol to oleic acid on the conversion of oleic acid were examined. The results illustrated that the esterification of oleic acid in supercritical methanol can be realized under much milder conditions (i.e. lower temperature, shorter reaction time as well as lower molar ratio of methanol to oleic acid) than the transesterification of grease in supercritical methanol. These suggested that triglycerides first hydrolyze to fatty acids and then the fatty acids undergo methyl esterification to form methyl esters in supercritical methanol. Therefore, it is feasible to use the feedstock containing higher water and free fatty acid, such as waste cooking oil and deodorizer distillate, to produce biodiesel in low cost with supercritical methanol.
Abstract: A kind of Keggin structural 12-WP acid was prepared and used as catalyst to synthesize methyl tertbutyl ether (MTBE) from methanol and tertbutanol. The influences of the amount of 12-WP acid, the ratio of reactants and reaction temperature on the yield of MTBE were investigated. The results showed that the conversion of tertbutanol, selectivity of MTBE and the yield of MTBE could be up to 59.6%，74.5% and 44.4%, respectively when the amount of 12-WP acid was 2.16% of tertbutanol and the mole ratio of tertbutanol to methanol was 1∶1.2 at 100℃.
Abstract: Zeolites Y of FAU type containing different transition metal heteroatoms (MY or M1M2Y, where M = Ti, Co, Ni, Mo, Zr, etc) in the framework were synthesized. The effect of different heteroatoms on the crystallinity of zeolite Y was characterized by XRD and SEM. The zeolites MY or M1M2Y exhibit the same phase profiles as zeolite Y by XRD. SEM results showed that MY zeolite is provided with welldefined crystal and larger crystal size. Zeolite Y containing single transition metal heteroatom (MY) exhibits lower crystallinity than zeolite Y. However, the zeolite Y containing two suitable heteroatoms (M1M2Y) has a much higher crystallinity than MY due to the collaboration of M1 and M2; there is an optimum composition for two heteroatoms to get a high crystallinity.
Abstract: Volumetric gas-liquid mass transfer coefficients were investigated in slurry bubble columns under elevated pressure and elevated temperature using a dynamic absorption method. The effects of system temperature, pressure, superficial gas velocity, concentration of solid on the volumetric mass transfer coefficients were discussed. The experimental results show that the system pressure, superficial gas velocity and concentration of solid are major factors affecting the mass transfer. The mass transfer coefficient increases with the increase of system pressure, temperature and superficial gas velocity, and decreases with the increase of solid concentration. Based on the experimental data, a correlation for the volumetric gas-liquid mass transfer coefficient of H2, CO, CO2 is obtained.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
