Abstract: Based on the enlargement of fine particles by heterogeneous condensation, removal of particles from LIFAC (Limestone Injection into the Furnace and Activation of Calcium) desulfurization system was investigated experimentally. Supersaturation required for fine particles growth was achieved by adding adequate steam to the wet flue gas at the inlet of condensation chamber. The enlarged dusty droplets were removed by a high efficiency demister. The particle number concentration, size distribution, temperature and humidity were measured in real time by ELPI (Electrical Low Pressure Impactor) and Vaisala humidity transmitter, respectively. The influences of activation water addition amount, steam addition amount, particle number concentration and demister on the removal of fine particles were investigated. The results indicate that supersaturation improve at first and then drop with the increase of steam addition amount. The removal efficiency of fine particles can be effectively improved by heterogeneous condensation. The removal efficiency rises with the increase of supersaturation, decrease of particle number concentration and the enhancement of performance of the demister.
Abstract: Pyrolysis experiments of coal, two kinds of municipal sewage sludge (S1 and S2) and the mixture were carried out in nitrogen atmosphere by thermogravimetric analysis. The pyrolysis characteristics of the coal and the municipal sewage sludge samples and the effects of sewage sludge on coal pyrolysis were studied. The coal and sewage sludge have different pyrolysis characteristics parameters in aspects of total weight loss, weight loss rate and volatile release temperature range. Appropriate mixing of S1 and coal is beneficial to the increase in the total weight loss and weight loss rate of pyrolysis reaction. There is partial overlap between the volatile release ranges of S1 and the coal. The inorganic matter in sewage sludge ash has catalytic effect on coal pyrolysis. The pyrolysis of the mixture of coal and S2 shows no obvious synergistic effect. The pyrolysis characteristics of the mixture of coal and municipal sewage sludge are related to the characteristics of samples and the mixing ratio.
Abstract: The influence of microwave drying on the pyrolysis of biomass was investigated compared with conventional air drying. The aim of this work is to seek the feasibility of using microwave drying technique in fast pyrolysis of biomass during pretreatment of the feedstock. The drying tests show that the drying rate of microwave oven is far faster than that of electrical oven. The inner pore characteristics of dried biomass are improved at higher drying rate. The thermogravimetric and kinetic analysis indicate that the microwave drying treatment promote the decomposition of biomass, especially cellulose and hemicellulose, and prevent the secondary reactions of primary vapor to a certain extent at the same time. As a result, the yield of bio-oil from biomass pyrolysis in a fluidized-bed reactor increases slightly. Thus microwave drying is a technically and economically feasible pretreatment method for fast pyrolysis of biomass and more in-depth works are needed to be carried out next step.
Abstract: The fast pyrolysis of hemicellulose in wheat straw was conducted in a tubular furnace at 550℃~850℃ to examine the products distribution and its mechanism. The result show that the gas yield is the highest compared with tar and char, and increases with the increasing of temperature. The gas is mainly consisted H2, CO, CO2, CH4 and hydrocarbon. The liquid products included acids, alcohols, furan, cyclopentenes and other aromatic compounds, and its relative yield changes slightly. The relative yield of char has contrary trend to that of gas. The isopropanol-extracted components remaining in the char are alcohols and other compounds with larger molecular weight.
Abstract: Torrefaction is a main pretreatment technology for improving the properties of rice straw in order to deal with such problems as dispersed resource, high moisture content, high bulk volume and low heating value. The straw after torrefaction was gasified in an entrained flow gasifier because of high heating value and good grindability. Straw samples were torrefied in a fixed bed reactor at 200℃, 250℃ and 300℃ for 30min under nitrogen atmosphere. The non-isothermal gasification was carried out in a thermogravimetry analyzer (TGA) with heating rate of 20℃/min and final temperature of 1200℃. The results show that the products are mainly solid product and gases, as well as a mount of condensable liquid (water and tar). The ratio of CO2 in gases is up to 80% remaining a little CO and CH4. The total weight of solid product decreases with increasing temperature of torrefaction, accordingly that of gas products increases; the liquid products changed little at different temperatures. The energy efficiency of torrefaction is about 40% to 60% and decreases sharply then drops slowly with increasing reaction temperature. The grindability of solid product is improved by torrefaction and easy to be pulverized for utilization in an entrained flow gasifier. The results of TGA indicate the biomass sample pretreated at higher torrefaction temperature has higher gasification reactivity. The mechanism of reaction between torrefied straw and carbon dioxide could be simulated by a two dimension distribution model (2D). The apparent activation energy calculated by Coats-Redfern method is about 73kJ/mol~88kJ/mol.
Abstract: The hydrophobic ionic liquid, \[BMIM\]\[BF6\] was synthesized, and the treatment conditions were investigated. When the extraction ratio is 1∶5, and pH=5, after 15min, the oil removal ratio is 95.6% and the CODCr removal is 93.5%. At the same time, the recovery of ionic liquids experiment was carried out. By the recovery ionic liquid, the oil and CODCr removal were 95.4%and 93.2% respectively, the results showed that ionic liquid can be regenerated and the effects are not reduced. The results indicate that the hydrophobic ionic liquids can remove the oil and organic compounds in the oilfield wastewater effectively. And the mechanism of ionic liquids was proposed.
Abstract: Molecular transformations of heteroatomic compounds during visbreaking of Venezuela Orinoco AR were studied by ultrahigh-resolution negative ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FT-ICR MS). The results indicated that the relative abundance of O2, O1, N1O2, S1, O1S1 and O2S1 are decreased or even disappeared, but those of N1, N2, N2O1, N2S1, N3, N3O1, and N1S2 are increased after the visbreaking. The highest relative abundance is O2 class in Venezuela Orinoco AR, while in the visbreaking product (VB) it is N1. The high abundance O2 class contains the species with double bond equivalents (rings plus double bonds, named DBE) 3 and 4 in the AR, which are 2 or 3 cyclic naphthenic acids. By visbreaking, the relative abundance of O2 class is decreased and carbon number is also reduced, mainly DBE 1~4 compounds. The highest abundance N1 class contains the species with DBE 12 in the AR. After visbreaking, a bimodal DBE distribution around 12 and 15 is observed for the N1 class, suggesting two possible stable core structures. The distribution of carbon number and highly abundance of carbon number distribution is reduced, suggesting that the side-chain cracking reaction is mainly concerned for N1 class compounds.
Abstract: Effects of reaction atmospheres (nitrogen, carbon monoxide, carbon dioxide, syngas and water vapor) on stability of the catalyst, selectivities to propylene and byproducts for dimethyl ether conversion to propylene (DTP) over Ca/ZSM-5 were investigated in a continuous flow fixed-bed reactor. Besides, the regenerated catalyst was also studied for DTP process. The results show that the catalyst exhibits best stability, highest propylene selectivity and lowest selectivities to byproducts in carbon dioxide atmosphere, followed by nitrogen, carbon monoxide and syngas atmosphere, and water vapor atmosphere exerts worst effect on DTP. The catalytic performance of the regenerated catalyst also demonstrates that carbon dioxide as reaction atmosphere is most beneficial to DTP process.
Abstract: KOH-modified TiO2 support was obtained by treating the hydrolysate of tetrabutyl titanate with KOH solution of various concentrations; the gold catalyst supported on the KOH-modified TiO2 was prepared through impregnation and used for CO oxidation. The support and catalyst were characterized by N2 physical sorption, thermogravimetry, thermo-analysis, X-ray powder diffraction, UV-vis diffuse reflection spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The results indicate that the modification with KOH may influence the structure and property of TiO2 and Au/TiO2 significantly. KOH modification can change electronic structure of TiO2 and enhance the activity of Au/TiO2 catalyst for low-temperature CO oxidation. However, the modification with excessive KOH may also block the porous structure of TiO2 and weaken its adsorption ability, which leads an enlargement of gold particles on Au/TiO2 and a decrease of its catalytic activity for CO oxidation.
Abstract: Cobalt based catalysts supported on amorphous SiO2 were prepared through thermal decomposition as well as incipient wetness impregnation. They were characterized by means of TG, XRD, TEM and TPR and used in Fischer-Tropsch (F-T) synthesis. The results indicated that Co/A200-I catalyst prepared by impregnation exhibits high F-T synthesis activity, though cobalt particles in it are in irregular shape. In comparison, the cobalt particles in Co/A200-D catalyst prepared through decomposition are in secondary spherical structure with relatively uniform diameter and the Co/A200-D catalyst exhibits high selectivity to light hydrocarbon in F-T synthesis. The specific surface area of SiO2 support also influences the structure of catalysts obtained. Compared with the Co/A200-D catalyst, Co/A380-D catalyst prepared by decomposition with higher surface area support is more difficult in reduction due to the stronger metal-support interaction; however, Co/A380-D exhibits higher catalytic activity in F-T synthesis, probably due to the higher cobalt dispersion
Abstract: A series of ZrO2-Al2O3 mixed oxides with different ZrO2 contents were prepared by using ZrOCl2·6H2O and Al2(SO4)3 as raw materials through ultrasonic coprecipitation method. CoMo/ZrO2-Al2O3 catalysts with 6.0% cobalt and 16.0% molybdenum loading were prepared by impregnation method. The BET， XRD， H2-TPR and NH3-TPD characterization results showed that the ZrO2-Al2O3 mixed oxide support had high surface area, large pore volume and pore diameter. The surface area of the ZrO2-Al2O3 mixed oxide support decreased with the increase of ZrO2 content in the mixed oxides. The active component of CoMo/ZrO2-Al2O3 catalyst was highly dispersed over the ZrO2-Al2O3 and the amount of the loaded CoMo was closed to the monolayer dispersion threshold. Compared to the CoMo supported on the single alumina or zirconia catalysts, the surface of the CoMo/ZrO2-Al2O3 catalyst had stronger reduction ability and more active acid sites, which led to its higher catalytic activity and benzene selectivity in the hydrodeoxygenation of phenol.
Abstract: The composite TiO2-ZrO2 support was prepared through co-precipitation of Ti(SO4)2 and Zr(SO4)2 solution and V2O5/TiO2-ZrO2 catalysts with different vanadium loadings were obtained by incipient impregnation with ammonium metavanadate solution. The catalytic performance of V2O5/TiO2-ZrO2 in the selective oxidation of methanol to dimethoxymethane (DMM) was investigated under mild reaction conditions. The V2O5/TiO2-ZrO2 catalyst performs better in the selective oxidation of methanol than V2O5 supported on the single oxide TiO2 or ZrO2. XRD, NH3-TPD, and H2-TPR characterization results indicated that the incorporation of highly dispersed ZrO2 in V2O5/TiO2-ZrO2 may enhance the surface acidity and the redox ability of vanadium species, which is favorable for the selective oxidation of methanol. The V2O5 loading influences the dispersion and structure of vanadium species that are related to the catalyst performance; a V2O5 content of 5%~10% is adequate to get V2O5/TiO2-ZrO2 of high performance for the selective oxidation of methanol to DMM.
Abstract: Dry methane with various concentrations was directly entered the anode of the solid oxide fuel cells (SOFCs) of Ni-YSZ/YSZ/LSM（Ni-Y2O3 stabilized ZrO/YSZ/La0.85Sr0.15MnO3-δ）. The exhaust gases from anode were measured in-situ by gas chromatograph (GC) to study the reactions of dry methane under different current densities at the Ni-YSZ anodes. The reactions were determined by comprising the theoretical open-circuit voltage (OCV) to the measured one, analyzing quantitatively the exhaust gas and the activation energy of elementary reactions occurred to CH4 at the Ni-YSZ anodes. At 1000℃ oxidation of methane was found to take place in sequence from partial oxidation, CH4+2O2- → CO+H2O+H2+4e-， CH4+3O2- → CO+2H2O+6e- to complete oxidation with increasing current density at the Ni-YSZ anodes under 3.85% and 5.66% CH4 conditions.
Abstract: The effects of Fischer-Tropsch (F-T) diesel fuel on the performance and emission characteristics of diesel engine with a high-pressure common rail system, which meets Euro Ⅲ emission standard(an Euro Ⅲ high-pressure common rail diesel engine), were studied. The experimental results indicate that with an increase of F-T diesel in mix fuel, the output power and brake specific fuel consumption (BSFC) decrease, and the effective thermal efficiency increases slightly. Compared to those for neat diesel fuel (DF), the maximum reduction of engine torque and BSFC for F-T diesel are 2.2% and 7.1%, respectively at full engine loads, while the maximum incremental value of effective thermal efficiency reaches 4.5%. The data of 13 mode test cycle (ECE R49) show that the presence of F-T diesel in fuels significantly decreases the exhaust emissions of CO, NOx, HC and PM with the maximum reduction of PM by 25.5%, NOx by 11.7%, HC by 39.3% and CO by 33.9%, respectively. On the whole, F-T diesel is an ideal alternative fuel for diesel engine.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
