Abstract: Interactions of sodium, silica and sulphur in a lowrank coal during pyrolysis was investigated to understand the retention of sulphur by sodium and the role of sulphur in particle agglomeration and defluidisation in fluidizedbed combustion and gasification. Samples of water and acid washed coal, and the acidwashed coal ionexchanged with sodium acetate were prepared and subjected to temperatureprogrammed pyrolysis performed in a muffler furnace with a constant heating rate of 17.7℃/min up to 1000℃. Char samples were withdrawn from the reactor and subjected to sequential water and acid leaching tests and SEM analysis employing Energy Dispersive Xray and quantitative Xray mapping. It was revealed that for chars removed at temperatures between 700℃～1000℃, part of the organically bound sodium forms water soluble compounds such as Na2O and Na(OH), a significant proportion of water soluble sodium silicates and acid insoluble constituents with sulphur in the char. The latter explained why the presence of organically bound sodium was found to retain sulphur during pyrolysis in previous investigations and also why the formation of Na2S was not observed as the retaining mechanism. The highly concentrated regions of sulphur existing around the edges of the sodium silicate inclusion bodies were considered to be the beginning of the sticky phases of sulphur bearing compounds responsible for binding bed materials together during fluidisedbed combustion and gasification. Total sulphur retention was found to increase by 10% as the NaAc solution concentration used in the ionexchange of the acidwashedandNaexchanged coal was increased from 0.25mol/L (2% total Na) to 1.0mol/L (3.2% total Na). A corresponding increase in the acidinsoluble sodium content suggested that the amount of acidinsoluble sodium/sulphur constituents increases with acetate solution and is the reason behind the effect of total sulphur.
Abstract: The reaction performance of supercritical Fischer-Tropsch synthesis in a fixed bed reactor was studied in this work. n-hexane was used as supercritical media. Three kinds of Co catalysts: impregnated catalyst, sprayed catalyst and bimodal catalyst were tested. Under the same Co content condition, the catalytic activity of the sprayed catalyst was similar with that of the bimodal catalyst, but higher than that of the impregnated catalyst. CO conversion over the sprayed catalysts was remarkably higher than that over the impregnated catalysts. Higher lighter fractions selectivity and lower 1-olefins content of FT products were observed over the sprayed catalysts. At the similar CO conversion conditions, however, the 1-olefins content over the sprayed catalyst was similar with that over the impregnated catalyst. For impregnated catalyst, CO conversion increased obviously from 8.3% to 43.6% when Co content increased from 5% to 15%. CH 4 selectivity for 5% Co catalyst was lower about 2.0%~3.0% than those of 10%, 15% and 20% Co catalysts. 1-Olefin content of products over 5% Co catalyst was obviously higher than those over 10%, 15% and 20% Co catalysts.
Abstract: A new method was applied to study the shrinkage characteristics of briquette during pyrolysis by realtime online images collection and computer image processing. The swelling and shrinkage characteristics of the briquette with different density were monitored using a digital camera during pyrolysis. Transient swelling and shrinkage phenomena were observed, and quantifative swelling and shrinkage were measured by computer images processing. The results show that the briquette begins to shrink at 400℃, and has two shrinkage ranges at 400℃~550℃ and 650℃~800℃. The lateral shrinkage and volume shrinkage decrease with the increase of briquette densities. The lateral shrinkage and the volume shrinkage were 12%~18% and 32%~44%, respectively at 1000℃ for 4 briquette samples with different densities. The volume shrinkage relates to sample contents of both the volatile matter and the ash. Generally, the volume shrinkage at 1000℃ increases linearly with the increase of the volatile matter or the decreas of the ash content of briquette samples.
Abstract: The effects of pyrolysis pressure and atmosphere on the CO2gasification reactivity of Shenfu char were investigated by using a pressurizedTGA. It is found that tar redeposition and repolymerization which occur during pressurizedpyrolysis under N2, i.e. tar secondary reaction, could influence the initial gasification reactivity of char significantly. The tar cracking product produced by tar secondary reaction would cover the surface of char particle and form a less reactive layer, which could overlay the inlet of micropores of char particle to decrease the accessibility of reactant to the reactive sites inside the particle and slow down the initial gasification reactivity of char. Hydrogasification during hydropyrolysis consumes the less reactive layer and the carbonaceous part of chars, which forms more reactive sites on chars. Higher hydrogen pressure is favorable for the hydrogasification and the increase of chars gasification reactivity. Compared with the pyrolysis under N2, hydropyrolysis is advantageous to increase the gasification reactivity of chars. Under N2 atmolsphere, tar secondary reaction would decrease the reactivity of chars. However, in the case of hydropyrolysis, the negative effects brought by tar secondary reaction can be rule out by the activation of the char by the hydrogasification. It is noted that under the experiment conditions used in this study, hydropyrolysis is favorable for increasing the gasification reactivity of chars either at atmospheric pressure or at higher pressures.
Abstract: Three different lithotypes of Longyan (LY) anthracite with different particle size were separated by means of flotation technique. Experiments of the particle fragmentation during pyrolysis and combustion were conducted in a TGA system and a pilot scale fluidized bed furnace, respectively. It is shown that for clarain and culm many new fine particles are generated during pyrolysis, most of which has a size smaller than 0.8mm. The primary fragmentation reaction of clarain and clum becomes severely with the increase of heating rate and the sample particle size. For durain particle, no obvious fragmentation is found under the same experimental condition. Factors, such as particle properties, particle size, furnace′s bed temperature and combustion time, have an important effect on the fragmentation of LY anthracite during its combustion in fluidized bed. Clarain and culm occur tremendous fragmentation in fluidized bed due to their compact structure, few large pores in inner particle, high microscopehardness (Hm,v) and low ash content. The fragmentation of clarain and culm tends to be severely with the increase of particle size, bed temperature and combustion time. Durain doesn′t have obvious fragmentation during combustion in fluidized bed. Both clarain and culm undergo the secondary fragmentation during combustion, but the secondary fragmentation of clarain is severely in the late stage of combustion. The particle size of clarain declines more rapidly than that of culm. In the early stage of combustion, the mean particle size of clarain decreases promptly as a result of primary fragmentation, but with the time going it falls to a stable size. The combustion model of clarain in fluidized bed is equidensity shrinking core model, while that of durain is equidiameter one, and that of culm is a mixed model.
Abstract: Structure characteristics of the different macerals of 5 lowtomedium rank coals were studied by means of 13C-NMR. The molecular structure characteristics and parameters of the macerals were discussed. The result indicates that the aromaticity of inertinite is higher than that of vitrinite. There is less aliphatic hydrocarbon in inertinite. The side chain of hydrocarbon in inertinite is shorter than that in vitrinite. With the increase of coal rank, the aromaticity of both inertinite and vitrinite increases, but the aromaticity of inertinite increases more slowly than that of vitrinite. The aromatization (not ringcondensation) is dominant in the period of coalification of lowtomedium rank, and this phenomenon is more remarkable in vitrinite than that in inertinite. Additionally, the result of 13C-NMR also shows that the total oxygen content in inertinite is lower than that in vitrinite.
Abstract: The experimental study on the Yangquan high-ash coal catalytic gasification with mixing-gas (air/steam) by using solid alkali (sodium hydroxide) or waste liquid of viscose fiber as the catalyst in a smallscale fluidized bed with 28mm i.d. was carried out. The loading saturation levels (LSL) of two catalysts in Yangquan high-ash coal are about 6%. Under the gasification temperature ranging from 830℃ to 900℃ and from 900℃ to 920℃, the apparent reaction order of Yangquan highash coal with respect to the unreacted carbon fraction approximates to 2/3 and 1/3 for the noncatalyst case, respectively. Also, the different values of apparent reaction order in the two temperature ranges are presented for the case with 3% solid alkali catalyst loaded. At the low temperature ranging from 830℃ to 860℃, the apparent reaction order of catalytic gasification is 1 since enough active carbon sites on the coal surface are formed during the catalytic gasification by solid alkali. But at the high temperature ranging from 860℃ to 920℃, the sodium carbonate produced by the reaction of solid alkali with carbon dioxide can be easily fused, transferred and redistributed, which affects the gasification reaction rate, and the apparent reaction order of catalytic gasification is reduced to 1/3.
Abstract: The combustion characteristics of soot generated in natural gas diffusion flame (homemade natural gas soot, NGS) were investigated using thermogravimetric analysis under different oxygen concentrations (21%, 15%, 10% and 5%), and compared with those of candle soot, 4 industrial NGS and one anthracite coke. The combustion characteristic parameters of the test samples can be achieved through data analysis. The results show that NGS sample has better ignition features and lower ignition temperature than other NGS samples and the coke with the low volatile matter. Under oxygen concentration of 21% the ignition temperature of homemade NGS is 483.0℃ which is 114℃ and 127.8℃ lower than those of the coke and the candle soot, respectively. The burning index ((dG/dt)max/ti2) of homemade NGS is lower than that of coke due to its high volatile matter. The combustion reactivity of homemade NGS is weak in the late combustion stage. With decreasing oxygen concentration the ignition temperatures of samples change within 50℃. The relative burnout time of homemade NGS is longest, 6.03 min under 21% oxygen concentration, which is 21.3% longer than that of coke. The difference of burnout property between homemade NGS and coke is small. The burnout time of candle soot is also long due to the small particle size of the soot. With decreasing oxygen concentration the burnout times of the samples are prolonged. For homemade NGS the burnout time is 2.97 times longer when oxygen concentration decreases from 21% to 5%.
Abstract: The control of the amount of alkali vapors in the flue gas at the gas turbine inlet is very important for the coalfired combined cycle power system. Based on the Gibbs free energy minimization principle of chemical equilibrium, two models of coalfired process and alkali migration were developed using Aspen Plus software to explore the migration mechanisms of alkali metals during coalfired process. Moreover, the effect of conditions on the limit level of alkali vapors were predicted. The model results show that in a wide reactor temperature range from 850K to 1650K, the concentration of alkali vapors increases with increasing the reactor temperature. Below 1400K NaCl vapor and KCl vapor are the major alkali metal species in the gaseous phase, and the concentration of Na2SO4 vapor is much higher than that of K2SO4 vapor. At below 1500K, concentrations of alkali vapors increase with the increase of chlorine in coal. At a constant temperature, concentrations of alkali vapors decrease with increasing the reactor pressure. Under atmospheric pressure, the concentration of alkali vapors is decreased to 2.4×10－8 by weight in 972K with 0.1% chlorine in coal, and when the chlorine in coal are 0.05% and 0.01%, the reactor temperature should be increased to 990K and 1025K to limit concentrations of alkali vapors lower than 2.4×10－8, respectively.
Abstract: Four subfractions (saturates, aromatics, resin and asphaltene, SARA) from Liaohe vacuum residue (LHVR) were cracked in the thermal, hydrothermal and catalytic hydrocracking system without or with detuerated tetralin and tetralin in a highpressure microreactor. The effects of Ddonor, Hdonor and molecular hydrogen on the cracking reaction of SARA were investigated. The results show that asphaltene is the major precursor of coke, and resin could produce some coke in thermal cracking. However, aromatics can hardly result in coking, and saturates is not precursor of coke compared with asphaltene and resin. In the hydrothermal cracking and catalytic hydrocracking systems, the trend of coking of SARA could be decreased by participation of molecular hydrogen, especially in the catalytic hydrocracking system. Three hydrogen sources including Ddonor, Hdonor and H2 could decrease the formation of coke and asphaltene of SARA, especially the first two donors. Ddonor and Hdonor have the similar effect on the cracking and condensation of SARA. However, there is clear isotopic effect between Hdonor and Ddonor based on the difference of donation ability at same condition. The stable isotope study shows that CH bond scission of tetralin or CD bond scission of detuerated tetralin is incorporated into the racecontrolling reaction pathway in the cracking systems of SARA. The degree of isotopic effect shows the racecontrolling reaction pathway depended on the reaction system. The isotopic effect in thermal cracking system was clearest among the hydrothermal cracking and catalytic hydrocracking systems as a result of the change of racecontrolling reaction pathway of thermal cracking of SARA by molecular hydrogen and dispersed catalysts.
Abstract: An activated carbon of wood origin was treated by a diluted sulfuric acid solution of KMnO4 (KS), concentrated nitric acid (CN) and thermal oxidation at 350℃ (HT). The structural properties and surface chemistry of the samples with different treatments were characterized by using sorption of nitrogen and Boehm titration, respectively. Oxidative removal of dibenzothiopene (DBT) with hydrogen peroxide catalyzed by the activated carbons was studied. The results showed that the oxidative removal of DBT is dependent on carbon surface properties. The effect of carbon surface properties on the adsorption of DBT is different from its effect on the oxidative removal of DBT; the increase of total acidic groups is favorable for DBT adsorption. The increase of the amount of carbonyl groups is obviously favorable for the oxidative removal of DBT due to a factor: surface carbonyl groups can accelerate hydrogen peroxide to produce hydroxyl radicals. The catalytic performance of activated carbon for the oxidative removal of DBT is improved significantly with the treatment of thermal oxidation at 350℃; the sulfur content in the noctane solution is decreased from 0.556g·L-1 to 0.009g·L-1.
Abstract: High reaction performance and decoking ability were obtained in gasphase oxidative cracking (GOC) of decalin, as compared with its pyrolysis reaction. In the GOC process, high liquid yield could be achieved at a low temperature; while at high temperature, the yield of lower alkenes can overpass the yield of liquid, in which the aromatics, especially BTX (benzene, toluene and xylenes), dominated the overall liquid compositions. The optimal reaction conditions for GOC of decalin are: temperature 700℃~800℃, residence time<0.4s, molar ratio of decalin to oxygen 0.3~0.5, where pure oxygen can be replaced by air for GOC process. Under the conditions of 800℃, nC10)/n(O2)=0.5 and a residence time of 0.4s, the yields of lower alkenes, BTX, and total liquid products reache 37%, 29%, and 50%, respectively.
Abstract: The macro-kinetic investiqations for catalytic hydrodelsulfurization of pyrolysis gasoline over an industrial Co-Mo/Al2O3 catalyst were carried out in an adiabatic tubular fixedbed reactor under the conditions: 2.5MPa～3.9MPa, 513K～655K, H2/pyrolysisgasoline molar ratio 1.8~3.5, and the mass concentration of thiophene, methylthiophene and dimethylthiophene in the feed pyrolysisgasoline, 838×10－6, 137×10－6~723×10－6 and 192×10－6~723×10－6, respectively. By means of Powell optimal method and Merson integral method, the power-law type macrokinetic models for the catalytic hydrodelsulfurization of pyrolysis gasoline were developed. The reaction orders of thiophene, methylthiophene and dimethylthiophene are 0.721, 0.735 and 0.870, respectively, and the activation energies are 70.0kJ·mol－1, 67.9kJ·mol－1 and 59.9kJ·mol－1, respectively. The conversion of thiophenic sulfides increases with the reaction pressure, but this increase is obviously slowed down at the reaction pressure above 3.5MPa. The increase of reaction temperature is beneficial to the conversion enhancement of thiophenic sulfides, especially above 563K. When the reaction temperature increases above 593K, the correlation between the conversion of thiophenic sulfides and temperature is almost linear. Therefore, for the Co-Mo/Al2O3 catalyst used, the favorable operating pressure is about 3.5MPa, and the reaction temperature should be higher than 593K.
Abstract: The influence of biomass tar on the overall thermal chemical process has aroused much more attention with the development of biomass gasification technology. Catalytic cracking is thought to be the most effective route for the solution of biomass tar elimination. However, the variation of tar constitution during the catalytic cracking process, which is most valuable for understanding of the process mechanism, is poorly known. One kind of chromatography was used to analyze the constitution of biomass pyrolysis tar, which results in good separation effect and high accuracy. The constitution of tar from different biomass sources and different catalytic cracking conditions was compared, and also the mechanism of catalytic cracking was discussed. On account of the composition of different biomass feedstocks, the content of aromatic and polar fraction in the tar from wood chip pyrolysis is higher than those from rice straw and rice husk. With the increase of pyrolysis temperature, the content of aromatic fraction in tar also increases. After catalytic cracking, the content of aromatic fraction in tar almost doubles, and is 50% with the cracking temperature above 950 ℃. However, other fractions decrease to different extents. The reason lies in that the reaction rate of aromatic fraction is smaller than those of other fractions, and also there is some conversion from other fractions to aromatic fraction. During catalytic cracking, the constitution of biomass tar has the trend of aromatization, which becomes obvious with the extent of tar conversion.
Abstract: A method has been developed for the release and determination of biomarker compounds in the covalently bound biomarkers of higher evolution sedimentary organic matters by catalytic hydropyrolysis HYPY/GCMS. The analytical results of steroids m/z 217 and hopanoids m/z 191 agree with the results obtained using DCM (CH2Cl2) Soxhlet extraction, and the hydropyrolysis yield is much higher than that of DCM extraction. It is considered that catalytic hydropyrolysis is a unique technique for biomarkers releasing from kerogen in high yield without affecting their biologicallyinherited stereochemistries, fewer carbon skeletal rearrangement, and mild reaction condition. The experimental results show that these primary components in the molecular skeleton of the sedimentary organic matter (SOM) can be released rationally by catalytic hydropyrolysis (HYPY), and applied in oil/oil correlation, oil/source correlation, the sedimentary environments of organic matter in oil pools, the secondary reconstruction of oil pools and other researches.
Abstract: The Fischer-Tropsch synthesis (FTS) over a spraydried ironbased catalyst reduced at different conditions was investigated in a continuous stirred tank reactor. The effects of reduction temperature and duration on the FTS performances as well as bulk compositions and other properties of the catalyst were determined. The results indicate that the extent of reduction and carburization was intensified by prolonging the reduction duration or by increasing the reduction temperature. The catalyst activity and stability was enhanced with the reduction at 270℃ compared with those reduced at lower temperature (240℃) or unreduced samples. The working catalyst loss during FTS resulted in the catalyst rapid deactivation at lower reduction temperature. The product distribution shifted towards lower molecular weight hydrocarbons with increasing reduction temperature or prolonging reduction duration at the same temperature.
Abstract: The low-temperature methanol synthesis from syngas was studied in a semi-continuous slurry reactor using Cu-Cr-Si-O catalysts promoted by zirconia. The catalysts were characterized by BET, TPR-H2, TPD-H2, TPD-CO, X-ray diffraction spectroscopy and X-ray photoelectronic spectroscopy. The results showed that zirconia plays an important role in the catalytic performance improvement. With the promotion of zirconia, the reaction activity increases by 32.5 %, the selectivity of methanol reaches a maximum of 96.2%, and the reaction stability improves obviously. Zirconia acts as an effective structural promoter. It gives an enhancement in surface area of catalysts, promots the copper dispersion on surface and brings about an enrichment of copper and chromium on surface. Meanwhile, zirconia acts as an electronic promoter and Cu+ exists steadily on surface. It could be concluded from the reaction and characterization results that the excellent performance of catalysts relates directly to the presence of Cu+ on the catalyst surface and an increase of surface area of catalysts, which is promoted by zirconia. On the catalysts surface, more complex active sites composed of Zr4+, Cr3+ and Cu+ provides the micro surroundings for the valence stability, which is a key factor for the activation of H-H bond and carbon-oxygen bond.
Abstract: Dimethyl ether (DME) is one of the best indirect liquefied products of coal. It can be used not only as the automobile fuel substitute for diesel engine, but also as the household fuel substitute for LPG. Because the oil resources in China can not meet the needs of the fast economic growth, DME is more likely to become a new generation of clean fuel. For DME synthesis in slurry phase, the stability of the catalyst is a key problem. For better understanding the deactivation mechanism of the catalyst, the experiments were designed as several individual reactions involved in the one step synthesis process, such as methanol synthesis, methanol dehydration and water gas shift reaction. Each reaction was carried out at the simulated reaction conditions like DME synthesis. In this paper, γ-alumina modified by V2O5 or Sm2O3 as the dehydration component of the composite catalyst for dimethyl ether synthesis was prepared by incipient wetness impregnation method. The DME synthesis catalysts were obtained by physically mixing the methanol catalyst and the equal granular size modified γ-Al2O3 at a weight ratio of 2∶1. The DME synthesis performances of the composite catalysts were evaluated in an agitated autoclave slurry reactor. Effluent gases were analyzed by on-line gas chromatographs using carbon sieve column and a thermal conductivity detector (TCD) for hydrogen, carbon monoxide and methane, GDX-401 column and a flame ionization detector (FID) for hydrocarbons, methanol and DME. The catalysts were characterized by H2-TPR, Pyridine-IR, reductive NH3-TPD and XRD. The H2-TPR results showed that CuO in the composite catalysts can be easily reduced with addition of V2O5 or Sm2O3. PyridineIR and reductive NH3-TPD indicated that the amounts of Brnsted acidic sites and Lewis acidic sites change much less when the γ-Al2O3 is modified. The ratio of the weak acidic sites to the strong acidic sites increases with the introduction of V2O5 and Sm2O3. XRD patterns revealed that either V2O5 or Sm2O3 disperses well on γ-Al2O3 and there is no new compound formed. In DME synthesis reaction, it was found that the γ-Al2O3 modified by V2O5 or Sm2O3 shows higher activity and DME selectivity compared to the unmodified one.
Abstract: In the previous paper, the catalytic performances of Cu/ZrO2 and the effects of the catalysts preparation parameters on the steam reforming of ethanol were investigated. In this paper, the influences of the reaction conditions on the reaction are further examined. Cu/ZrO2 catalysts were prepared by precipitation/alcogel and impregnation methods. The ethanol steam reforming reactions were carried out in a flow-type fixed bed micro-reactor (quartzes tube) at atmospheric pressure. The catalysts were also characterized by H2-TPR. The influences of the reduction temperature of the catalysts, reaction temperature, water/ethanol ratio and space velocity on the steam reforming of ethanol and the stability of Cu/ZrO2 catalyst were investigated. The results showed that the conversion of ethanol increased while H2 selectivity decreased with the increase of the reaction temperature in the range of 300℃～500℃. The influence of the reduction temperature of the catalysts on the conversion was not significant, although the reduction at 300℃ or 400℃ was favorable for the H2 formation in the reaction. High water/ethanol ratios resulted in the high ethanol conversion and high H2 selectivity. With the increase of space velocity, the ethanol conversion and H2 selectivity decreased. 8％Cu/ZrO2 showed relatively high stability for 22h at 400℃~450℃.
Abstract: The products from Fischer-Tropsch synthesis process, without S, N and aromatic hydrocarbons, are clean and environmentally friendly. But they contain a large number of alkene and oxygenates, especially acid oxygenates, which erode equipment and need to be hydrorefined. Therefore, the study on the novel hydrodeoxygenation catalysts for F-T synfuels is of great significance. Hydrodeoxygenation of oxygenates (n-butanonide，butyric acid and butanone) and intermediate products were investigated over Ni-M/γ-Al2O3（M=Co, Cu, Fe, La）catalysts. The influences of reducing behavior and surface dispersion of the catalysts on the catalytic performance were intensively studied. The results show that Cu and La facilitate the reduction of the NiO, but adding Co makes it difficult to be reduced. Co, Cu, Fe and La all increase the dispersion degree of NiO on the surface of the catalysts in the order of Co>Fe>La>Cu, which can improve the catalytic activity. The Ni/γ-Al2O3 catalysts added different metals show different activity and selectivity. Nickelbased catalyst with Fe as a promoter demonstrates better activity to butyric acid；adding La in nickel-based catalyst results in better performance of hydrodeoxygenation to n-butanonide； nickel-based catalyst with Co metal is more beneficial to improve the deoxygenation to butanone. Besides, n-butanonide and butyric ester are intermediate products in the course of hydrogenation of butyric acid.
Abstract: Hydrothermal crystallization method was used to synthesize Co-substituted aluminophosphate molecular sieves (CoAPO-11). The results of XRD, SEM, FTIR, N2 adsorption-desorption analysis and UV-visible spectroscopy show that Co is incorporated into the framework. CoAPO-11 possesses Lewis and Brnsted acid sites, and the latter is important for skeletal isomerization. Isomerization reaction results of 1-hexene over CoAPO-11 molecular sieve show that the temperature and space velocity have a significant influence on the reaction. The catalyst shows good isomerization properties at around 300℃ and space velocity of 2.4h－1.
Abstract: The Friedel-Crafts acylation of toluene with acetic anhydride to methylacetophone in liquid phase with silica-supported 12-phosphotungstic acid (PW/SiO2) as catalyst were investigated. PW/SiO2 catalysts prepared with different calcination temperatures and PW loadings were characterized by X-ray diffraction (XRD), thermo-gravimetric analysis (TGA) and NH3 temperature-programmed desorption (NH3-TPD). The effects of catalyst composition, pretreatment and reaction conditions on the reaction behaviour were examined. The results showed that the PW loadings and calcination temperatures have significant influences on the acidity, PW dispersion and catalytic activity of PW/SiO2; the catalyst calcined at 300℃ with a PW loading of 40% exhibits the best catalytic performance. For the acylation of toluene with acetic anhydride over PW(40%)/SiO2 at 130℃, the highest methylacetophone yield was achieved with the weight ratio of catalyst to acetic anhydride being 2.2.
Abstract: The dynamic sulfur emission from combustion of blends of coal liquefaction residue(CLR) and biomass (sawdust, MX and leaves, SY) was studied in a tubular furnace. The results show that the curves of sulfur release in combustion of CLR or the blends gently increase with temperature, and the curves of sulfur release rate have two-peaks. Two sulfur release peaks are generated from different organic and inorganic sulfur forms in CLR and biomass. For the blends, the sulfur release is mainly determined by the high sulfur content of blends, which is CLR. With the decrease of CLR ratio, the amount of sulfur release and two maximum values of sulfur release rate derived from blends combustion all decrease, while the times for occurrence of the two characteristic peaks are both postponed.
Abstract: Pre-combustion desulfurization of coal is an important method to control SO2 emission in a coal fired power plant. Desulfurization of Huayinshan coal with sub-critical water in a semi-continuous reactor was studied. The effects of temperature (320℃~450℃), pressure (5MPa~15MPa) and extraction time (10min~100min) on the removal of sulfur and weight loss of coal were examined. The results show that with the increase of temperature, pressure and reaction time the weight loss of coal and the removal of total sulfur in coal increase, and with the increase of temperature and reaction time the removal of organic sulfur-increases. At higher temperature, sub-critical water has the characteristic of selective desulfurization. The inorganic sulfur removal is mainly a physical process. Below 370℃ the organic sulfur removal is higher than inorganic sulfur removal, but above 370℃ it is opposite. It is suggested that considering the practicability, the suitable high temperature and low pressure should be taken in the sub-critical water operation condition.
Abstract: NOx formation behaviors of two kinds of RDF (Refuse Derived Fuel) samples with different N content were studied using a fluidized bed combustor. The results show that RDF samples are easily to be combusted in the fluidized bed reactor and the combustion process is stable without external energy. The distribution of NOx contents depends on the temperature distribution along the height of the fluidized bed. Under the same operation conditions, the higher nitrogen content in the RDF sample leads to higher NOx concentration in the flue gas. Both the extra air ratio and the injection of secondary air can affect the NOx formation characteristics, especially for the RDF with high nitrogen content.
Abstract: Due to coexisting of H2, CO2 and H2O with CO in hydrogen-rich gas produced from methanol reforming, the selective CO oxidation is companied with the side reactions of H2 oxidation, as well as CO or CO2 methanation and reverse water-gas shift reaction（RWGS）. This paper investigated the effects of the above side reactions on the selective CO oxidation over a 0.5% Pt/Al2O3 monolithic catalyst. The results showed that after 50% H2 is added into the reactants, the highest CO conversion is only 98.3% at 180℃ when the feed molar ratio of O2 to CO is 1, and the corresponding outlet CO concentration is 180×10－6. Adding 50% H2 into the reactants accelerate CO oxidation at low temperatures; the catalyst active reaction temperature window shifts down about 40℃. CO produced from RWGS is 80×10－6 at 200℃ indicating that the effect of RWGS on selective CO oxidation becomes obvious at temperatures higher than 200℃. On the other side, CO or CO2 methanation does not take place even at 300℃ under current conditions and has little effects on the selective CO oxidation.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
