Abstract: The removal of mercury from coal using sub-critical water extraction in a semi-continuous reactor was studied. The effect of temperature, pressure and extraction time on the removal rate of mercury was examined. The results show that in the temperature range 290 ℃～380 ℃, the higher the temperature is, the larger the mercury removal rate is. And the mercury removal rate increases with reaction pressure and residence time under the pressures from 5 MPa to 15 MPa and residence time from 10 min to 100 min. The maximum removal rate of mercury can reach above 96% under the conditions of 380 ℃, 15 MPa and 60 min.
Abstract: The characteristics of sulfur release during HT-coal combustion in the mixed-CO2 gas with different concentrations of oxygen were studied. The results show that during combustion in low oxygen concentration flow the rate curves of H2S and SO2 present two clear peaks, the quantity of released H2S increases and the whole time of sulfur release is prolonged. On the contrary, during combustion in high oxygen concentration flow the rate curves of H2S and SO2 show single peak, the time of sulfur release shortens. Because of improvement of self-capturing sulfur ability of the ash, the quantity of sulfur release is reduced during combustion in the mixed-CO2 gas with low oxygen concentration. The quantity of sulfur release from coal burned in high oxygen concentration flow is close to that burned in the air flow.
Abstract: Co-combustion of petroleum coke with coal is an effective and attracting method to treat the petroleum coke. In this work, the thermogravimetric analyses on the pyrolysis and combustion performance of adopted bituminous coal, petroleum coke and their mixed fuels were conducted. The chemical kinetic parameters including the apparent activation energy E and the pre-exponential factor A0 were obtained based on the thermogravimetric results. The experimental results indicate that the starting pyrolysis temperature changes little with the decrease of the ratio of coal to petroleum coke, the rate of volatile release slows down, the temperature corresponding to the maximum rate of volatile release is increasing, and the final weight loss is reducing. The chemical kinetic parameters (E and A0) are increasing. By contraries, when the ratio of coal to coke is increasing, the ignition and burn-out temperature and the temperature corresponding to the maximum combustion rate are decreasing.
Abstract: The aim of this paper is to remove the polycyclic aromatic hydrocarbons (PAHs) from hot gas during coal combustion. The adsorption for PAHs including Napthalenene (Nap), Fluorene(Flu) and Phenanthrene(Phe) with six sorbents was investigared. The effect of the textural properties of sorbents and isothermal adsorption behavior of a coal-based active carbon were examined in details. It can be concluded that the BET surface area and micro pore volume of sorbent are the determinant parameters for the PAHs removal. Furthermore, no obvious relationship is found between mesopore volume of sorbent and PAHs adsorption capacity. The adsorption capacity of sorbent is enhanced with increasing PAHs concentration and temperature. The adsorption amount of three PAHs on active carbon increases with their carbon numbers and aromatic ring numbers. The lower the PAHs volatility is, the higher the adsorption amount is.
Abstract: The effect of metal salts on the physical structure of CaCO3 was studied by using sodium carbonate as the additive and PoreMaster-60 mercury porosimeter. The investigation shows that the BET surface area and porosity increase and the pore distribution of CaCO3 is optimized, especially, the effect is more evident as the ionic ratio of calcium to sodium is equal to fifteen. At the same time, the characteristics of SO2 release from coal combustion in the atmosphere of O2/CO2 with adding CaCO3 was compared to that with adding modified CaCO3 by using ZCS-1 intelligent sulfur analyzer, and the ash melting point test and XRD analysis were carried out with the combustion products. The results show that without aggravating slagging, the SO2 retention is enhanced by modifying CaCO3, and the best sulfur fixation efficiency is reached at 1 000 ℃.
Abstract: Based on the mechanism of reducing NOx emission with staged-air combustion technology, the numerical simulation using CFD (FLUEBT6.0) software on the combustion process in the cold and hot states with staged-air technology for a 330 MW coal-fired power plant and the comparison of simulated NOx emission values with the tested NOx emission data were conducted. The results indicate that aerodynamic distribution is symmetrical in a utility boiler with opposed-installation whirl burners. The temperature first rises along with furnace height and then slightly decreases. In the combustion zone, the temperature and NOx concentration are the highest, while the oxygen concentration is the lowest. Without reconstruction and additional equipment cost, the staged-air technology can reach a low NOx emission by regulating some burners for the existing boilers.
Abstract: Experimental investigation was performed for catalyst deactivation by coking in the catalytic cracking process of biomass tar using dolomite and limestone as catalysts. The coke content and tar conversion were monitored during long-term operation. The longest time-on-stream of catalyst is 32 h. It is found that the coke content in the catalyst varies between 3 to 15 percent, and tar conversion drops to about 70 percent. The comparison of coking tendency of tar from different sources was made, and the effect of cracking conditions on coking process was also investigated. The relation between catalyst activity and coke formation was correlated from the viewpoint of kinetics. A linear expression based on the monolayer carbon deposition and an exponential expression based on the multi-layer carbon deposition were obtained separately.
Abstract: In utilization of biomass, it is very important for an exact determination of ash characteristics. However, there are no specific standards for biomass-ash analysis in China. The standards for coal-ash analysis are usually used to determine the property of ash in biomass. For a better understanding to the effects of different analysis methods on the results, 8 biomasses including wood dust, cornstalk, corn cob, rice shell, soybean stem, cotton stem, bark and leaf, were ashed at low temperature (corresponding to the temperature required in the standard of ASTM/E 870-82, amended in 1998) and at high temperature (corresponding to the temperature required in the standard of GB/T212－2001). The contents of ash were measured and the composition and morphology of the ash were analyzed using EDX-SEM. The results reveal that ashing temperature has a remarkable effect on the ash content, composition and morphology. Thus it is better to use low temperature ashing method for an exact determination of ash property. A proposal that the standards of biomass quality analysis should be established as soon as possible in China is put forward.
Abstract: The formation of acetylene by coal plasma pryolysis is strongly dependent on coal properties. The purpose of this paper is to elucidate the effects of coal properties on the acetylene formation and coking in plasma pyrolysis in H2/Ar. 12 kinds of coals with different coal rank were chosen and the effects of coal properties, including the content of volatile matter, oxygen and ash, on the yields of acetylene and coking were investigated in details. The results show that the bituminous coals containing the volatile matter from 30% to 40% have higher acetylene yield, while the coals with high oxygen content have lower acetylene yield, which corresponds to an increase in carbon conversion to carbon oxides. The content of mineral matter in coal has no significant relationship with the acetylene yield though it would increase the formation of CO. The higher mineral-matter content in coal is found to have a specific effect on the coking. The results of the tests by adding SiO2 and sands indicate that the high content of mineral-matter would increase the coke formation and affect the configuration of coke.
Abstract: In order to utilize the agricultural waste corncob comprehensively and effectively, the composition of gaseous and liquid products and the kinetics of pyrolytic process have been investigated. The experimental results show that the gases are mainly composed of CO2 and CO at 350 ℃～400 ℃ which account for nearly 95%. When the temperature is further increased, the yields of CO2 and CO are gradually decreased, but the yields of H2, C2H4, CH4, C3H6 and C3H8 are gradually increased. The gases have nearly 50% of CO and H2 at 450 ℃～500 ℃. The composition of liquid produced during pyrolytic process is analyzed by GC-MS and IR, which reveals that the oxygenated organic compounds such as phenol, furanmethanol, etc. are the main components and a lower temperature benefits the formation of phenol and its derivatives. The analysis of kinetics with TGA elucidates that the pyrolytic process includes two steps. For the first step in the temperature range 211 ℃～290 ℃, the pyrolysis reaction is third order, and it is a half order for the second step at 290℃～418℃, which have the activity energy of 121.47kJ·mol－1 and 105.7kJ·mol-1, respectively.
Abstract: A thermogravimetric system was designed, in which a large amount of sample (about 10 g) can be examined. The pyrolysis characteristics of the mixture of typical organic components (paper, wood, fibre, plastic, rubber and food residue) of MSW (municipal solid waste) were studied. The pyrolysis kinetics model, which consists of several parallel reactions, was obtained using the least square algorithms. The results calculated by the model have good agreement with the experimental ones. Based on these results, the interactions and nonlinear phenomena in pyrolysis of the mixture were analyzed. The results show that the pyrolysis kinetics model of the mixture of typical organic components of MSW consists of 2～4 parallel reactions. Sometimes parallel reactions merge during pyrolysis. Heat effect and the mixing proportion have remarkable effect on the overall pyrolysis characteristics of the mixture.
Abstract: The sorption of C5 paraffins in AlPO4-5 molecular sieves at 303K～675K was simulated by Monte Carlo method with Cerius-2 developed by MSI. The Henry constant, the isotherms and the average potential energy of C5 in the framework were obtained. It was observed that the sorption capacity of 2-methylbutane was higher than that of cyclopentane at 373 K, and this sequence was reversed at 473 K; the sorption loading of cyclopentane was higher than that of 2-methylbutane and n-pentane at 573 K under 0～20 kPa, which could be well interpreted based on the packing fashion of sorbates in the channel of AlPO4-5 molecular sieves. Moreover, the average potential energy of C5 decreased with the increase of the loadings at higher loadings. A sharp decrease of average potential energy was found for both of 2-methylbutane and cyclopentane when the loading was higher than 1 molecule/unit cell.
Abstract: A continuous mixed flow reactor, in which the supported heteropolyacid catalyst HPR-12 were suspended, was used in the experiment. Experimental data were adopted in parameters estimation for model of deactivation kinetics of benzene alkylation. Parameters, including deactivation rate constant, deactivation activation energy, exponent of retaining activity coefficient and reaction order in olefin molar concentration, were determined. They are 12.057 2 m3/(mol·s), 70552J/mol, 1 and 2 respectively. The deactivation kinetics model for benzene alkylation with linear olefine was thus established. Statistics test has shown that the deactivation kinetics equations are highly credible under the condition α=0.005 and well correspond with principle of benzene alkylation.
Abstract: The NiO/MgO catalysts were prepared by impregnation and calcination at different temperatures, and then were characterized by TPR, XRD, BET and Chemisorption techniques. The performance of NiO/MgO catalysts in coupling the partial oxidation of methane and CO2 reforming to prepare syngas was studied in a fixed-bed reactor. The results show that a solid-solution complex of NixMg1－xO is formed when NiO/MgO catalyst is calcined at 800 ℃. Although the complex catalyst exhibits low reducibility compared with the catalysts calcinated at low temperatures, a higher metal dispersion and a smaller Ni cluster size can be acquired. Because metallic Ni still remains strong interaction with MgO, the sintering of Ni is prevented. Thus, the carbon deposition is inhibited, which contributes to the high stability of the NixMg1－xO catalyst. While for the catalyst calcined at 900 ℃, low initial activity is exhibited due to the formation of much uniform bulk solid solution that is more difficult to be reduced to metallic Ni.
Abstract: The objective of this paper is to study the surface acidity and catalytic performance of the catalyst for alkylation with kinetic methods. A temperature-programmed desorption (TPD) kinetic model related with heating rate, temperature and n-Propylamine overlay fraction of catalyst surface acid sites at maximum rate of desorption was determined, and a method characterizing acid density, acid strength and the distribution extent of acid strength was developed. The TPD results indicate that the distribution extent of catalyst surface acid sites broadens firstly and then restricts with increasing catalyst activation temperature, which reaches the broadest at activation temperature of 350 ℃. It was revealed that the acid density and acid strength of the catalyst acid sites change from rise to drop with increase of the catalyst activation temperature and approach to maximum at 250 ℃ and 350 ℃, respectively. The relationship between the acidity and catalytic performance of catalyst exhibits that the stronger acid strength of catalyst is, the larger rate constant of catalyst deactivation is and that the alkylation rate constant is affected by the acid density and acid strength of catalyst. The stability of the catalyst could be improved by increasing the acid density and reducing the acid strength of the catalyst.
Abstract: The nano-sized Ni/Y2O3 catalyst prepared by impregnation-hot decomposition-hydrogen reduction(IHDHR) method and impregnation-hot decomposition (IHD) method was studied. The structural characteristics of the catalysts were carried out through X-ray Photoelectron Spectroscopy(XPS), X-ray diffraction(XRD) and BET area. The catalysis- properties of the catalysts were tested using a fix bed reactor fitted in a programmable oven. The Ni/Y2O3 catalyst reduced by hydrogen exhibited high activity for ethanol steam reforming with the conversion of ethanol of 95.3% and the selectivity of hydrogen of 53.6% at 320 ℃, with ethanol conversion of 81.9% and hydrogen selectivity of 43.1% at 250 ℃. The ethanol conversion and hydrogen selectivity were kept about 93% and 53.2% respectively after 60 h stability test at 320 ℃. The test results show that the catalyst reduced by hydrogen has higher activity for ethanol steam reforming at low temperature.
Abstract: Montmorillonite, one kind of the natural clay, is a promising catalyst support, but its application under actual circumstance is limited due to the small basal spacing (d001) and the weak thermal stability. In the present research, one kind of raw montmorillonite, produced in Shandong Province of China, was pillared by oligomeric hydroxyl Al and AlM (M=Zr, Ce) cation with 20 mmol/g of (Al+M)/clay and changing M/Al ratio to make pillared-clay(PILC). The d001 of Al-PILC and AlM-PILC measured by X-ray diffraction is 1.86 nm～1.92 nm and remains near 1.80 nm even calcined at 500 ℃, while that of raw montmorillonite is only 1.53 nm, which suggests the basal spacing of PILC is enlarged and subsequently its thermal stability is improved by Al and AlM pillars. Copper catalysts supported on PILC were prepared and applied in the catalytic combustion of methane. The results show that the CH4 conversion over Cu catalysts supported on AlZr- or AlCe-PILC, which exceeds 90% at 550 ℃ of reaction temperature, is largely higher than that over Al-pillared catalysts.
Abstract: A palladium based catalyst was used to synthesize dimethyl 1,4-cyclohexanedicarboxylate via the hydrogenation of dimethyl terephthate under low pressure. The influences of temperature, pressure, liquid space velocity and hydrogen-to-dimethyl terephthate ratio on the reactivity were investigated. The durability test of the catalyst was carried out for 200 h. The result showes that the conversion of reactant increases dramatically with the rising of the temperature and the hydrogen-to-dimethyl terephthate ratio while the selectivity changes slightly. Further more, both of the conversion and the selectivity decrease with the increase of the liquid space velocity. However, the pressure has little effect on the reaction. The conversion of dimethyl terephthate and the selectivity to dimethyl 1,4-cyclohexanedicarboxylate are higher than 95% and 94% respectively. Metallic palladium is the main active center of the catalyst.
Abstract: The acidity and texture of HZSM-5 zeolites (ratio of silica-to-alumina is 38) treated with steam at different temperatures were studied by XRD, NH3-TPD, IR, specific surface area and pore texture determination. The results show that the crystallinity of HZSM-5 zeolites reduces slightly with the increase of treating temperature. NH3-TPD reveals that the acidity decreases remarkably after steam treatment. The weak acid sites increases, while the strong acid sites decreases relatively with the increase of temperature. A definite blue shift in IR wave number was observed when the sample was hydrothermally treated at different temperatures. The surface area and microporous volume decrease, while mesoporous volume increases.
Abstract: A series of beta zeolites supported palladium catalysts were prepared by ion exchange (IE) or incipient wetness impregnation (IWI). The characterizations such as XRD，N2 adsorption and temperatureogrammed desorption（TPD）of ammonia were carried out. Hydrogenation of tetralin was conducted with a continuous-flow fixed bed micro-reactor under 4 MPa, 270 ℃，WHSV 16 h－1 and 100 mg/kg S (thiophene as S source). It is found that catalytic behaviours of the supported Pd catalysts depend both on the preparation methods and on the properties of supports. For Pd/Beta25，the catalytic activity of the sample prepared via ion exchange (IE for short) is superior to the initial wetness impregnated（IWI for short）one. Among three ion exchanged catalysts, Pd/Beta80(IE) is most active and sulphur tolerant during the whole time on stream. Pd/Beta25(IE) deactivates most rapidly because the conversion of tetralin decreases from the initial 77% to 10% after 8?h. With Pd/Beta60(IE), the corresponding conversion are 60% and 16% respectively. And with Pd/Bera80(IE) those are 75% and 55% respectively. The excellent activity of Pd/Beta80(IE) can be attributed to the carrier's higher strong acidity/weak acidity ratio, especially the presence of more medium strength acid sites and the mesopores structure. Besides，the addition of alumina to Pd/Beta25 is favourable to improving its catalytic activity.
Abstract: The CuZnAlO catalyst prepared by co-precipitation and the catalyst derived from hydrotalcite-like layered double hydroxides(LDHs) precursors were studied in this paper. For Cu based CuZnAlO, the methanol conversion，H2 yield and selectivity were improved greatly when ZrO2 was added as the promoter. COPZr2 with 10% of Zr shows the best catalytic performance. Its optimized reaction conditions in SRM(steam reforming of methanol) were confirmed as follows: 250 ℃, 0.1 MPa, H2O/MeOH=1.3, WHSV=3.56 h－1, no carrier gas. During the 150 h stability test of COPZr2, the methanol conversion and H2 yield were kept at 88% and 83% respectively; and the H2 and CO content in outlet were >63% and 0.20%～0.31%, which indicates that the catalysts possess good stability. The catalysts derived from LDHs precursors show high H2 and CO2 selectivity.The methanol conversion and H2 yield are improved when ZrO2 is added. LDHZr2 with 30% of Zr shows the best catalytic performance. During its 70 h stability test, the activity decreases at first and then methanol conversion and H2 yield are kept at 73% and 66% respectively; and the H2 and CO content in outlet are >55% and 0.07%～0.08% respectively, which indicates that such catalysts have good CO2 selectivity and low outlet CO content. The Scanning Electron Microscope (SEM) and X-ray Diffraction (XRD) results of the catalysts derived from LDHs precursors show that ZrO2-promoter can improve the dispersion of CuO crystals.
Abstract: In view of cement calciner technology, the sulfur-fixation properties of cement raw material during its combustion were evaluated by SC-132 sulfur analyzer. The mineral composition and microstructure of calcined sample were analyzed by XRD and SEM. The micro-mechanism of sulfur-fixation reaction at high temperature was discussed. The results show that thermal stability of sulfur retention mineral is a crucial factor in affecting the sulfur-fixation efficiency at high temperature. Cement raw materials have good sulfur-fixation ability within the temperature range tested. The sulfur-fixation efficiency is above 85% at 850 ℃～1 300 ℃. CaSO4 is formed at 850 ℃ and begins to decompose at 1 050 ℃. The thermal-proof complexes of 3CaO·3Al2O3·CaSO4 and Ca5(SiO4)2SO4 are formed at 1 050 ℃～1 250 ℃. The eutectic phase of ferroaluminate and silicate formed at 1 300 ℃ envelop the surface of CaSO4 and suppress its further decomposition, which results in the high efficiency for sulfur-fixation of cement raw materials at 1 300 ℃.
Abstract: The method using effective components of naphthalene oil to synthesize the additive for coal water slurry (CWS) was studied. Through proper experimental design and multianalysis of linear regress, the optimum synthesis conditions were obtained. That is, 30 mL H2SO4 was added into naphthalene oil (75 g) to initiate a sulfonation reaction at 160 ℃ for about 2 h. After hydrolysis, 25 mL HCHO was put into the reactor to cause a condensation reaction at 105 ℃ for 1.5 h. Experiments of CWS preparation with the additive synthesized and with the pure naphthalenesulfonic acid formaldehyde condensation product indicate that the additive synthesized has good dispersive property and low cost. The functional groups of the present additive are investigated by Fourier Transform Infrared Spectroscopy (FTIR), which indicates that the additive contains some aromatic compounds with －CH2－，－SO3－functional groups. Finally, the mechanism for improving the property of CWS by the additive is probed preliminarily.
Abstract: The 1.5% Au/Fe2O3 catalysts prepared by an inverse co-precipitation method calcined at different temperatures was characterized by XRD, XPS, TEM, BET, and tested by CO selective oxidation in H2-rich gas. The results show that the chemical composition and activity of the catalysts are greatly changed with the variation of calcination temperature. The catalyst Au/Fe2O3 calcined at 20 ℃, highly dispersed particles with the partially oxidized gold species on the support with the mean diameter of 3 nm～5 nm, displayes the best activity and selectivity of CO selective oxidation. However, the catalytic activity of Au/Fe2O3 decreases drastically with increasing calcination temperature due to the aggregation of metallic gold and bigger particle sizes. It is found that the catalytic behavior is related to the gold particle size but the nature of the support. On the basis of characterization data, in addition to the particle size of metallic gold, the oxidation states of gold are proven to be important for CO selective oxidation in H2-rich gas.
Abstract: A continuous mixed flow reactor, in which the supported heteropolyacid catalyst HRP-12 was suspended, was adopted in the experiment. Experimental data were used in parameters estimation for kinetics equation of benzene alkylation with linear olefin. Parameters, including reaction rate constant, activation energy and reaction order in olefin molar concentration, were determined as 13 530 s－1, 48743Jmol－1 and 1 respectively. The kinetic equation for benzene alkylation with linear olefin was thus established. Statistics test and model prediction have shown that the kinetics equation is highly credible under the condition α=0.05 and well corresponds with reaction principle.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
