Abstract: Release behaviors of selenium (Se) during pyrolysis of seven Chinese coals were studied at 200℃～1000℃ in a quartz tube fixed-bed reactor. Effects of heating rate, residence time and atmosphere on the release of Se in HDG and HLH coals were investigated. The results show that the release of Se mainly occurs below 700℃. The release ratio of Se is about 34%~63% at 700℃. The release of Se is peaked at 500℃ for bituminous coal and 400℃ for lignite, respectively. There is no significant effect of heating rate on the release ratio of Se when temperature is lower than 500℃. However, the lower heating rate leads to the higher release ratio of Se above 500℃. At 1000℃, the release ratio of Se increased with residence time within the first 15min, while there is no significant change with the further increase of the time. In comparison with N2 atmosphere, both air and H2 promote the release of Se, especially the air atmosphere. Under the experimental conditions, no Se enrichment in pyrolysis char is observed.
Abstract: Co-liquefaction of coal and polystyrene (PS) in supercritical water (SCW) was studied in an autoclave. The experiments were carried out to investigate the effects of water to reactant ratio(10~30) (mass ratio), temperature (360℃~430℃) and the addition of plastic（10%~40%）(mass ratio) on the coal conversion, yields of asphaltenes, oil and gas. The results show that with the increasing ratio of water to reactant, the total coal conversion increases at first and then remains constantly; while the yield of oil and gas keeps increasing. The conversion of coal and the yield of oil and gas increase dramatically with the temperature increasing above 420℃. It is found that the conversion reaches the maximum value as 31.2% at 430℃, while the yields of oil and gas, asphaltenes are 12.6% and 18.6%, respectively. The yields of oil and gas for co-liquefaction of coal and plastic are higher, typically by 0.6%~2.7%, than the weighted average oil and gas yields for the coal and plastic alone, which implies the synergistic effects on coal conversion.
Abstract: Compared to metal oxides， CaSO4 adopted as oxygen carrier （OC） in chemical looping combustion （CLC） presents several advantages such as low cost， easy availability and superior oxygen transfer capacity， whilst the SO2 emission and solid sulfur deposit in the process could be a big concern. In this study， thermodynamic simulations were conducted to investigate the sulfur distribution in a CLC system with CaSO4 as OC and syngas derived from coal as the fuel. Several findings were attained:（i） On the main products and reaction pathways in the fuel reactor （FR）， at the low temperature of 100℃~400℃， the main sulfur species and carbon deposit were H2S and CaCO3 via the methanation of CO with H2 coupled with the shift reaction of CO with H2O（g） and the ensuing thermochemical sulfate reduction （TSR）. Then at 400℃~915℃， CaS and CO2 were the main products through the reaction of CaSO4 with H2 or CO， and both products increased with increasing FR temperature. Furthermore， at the FR temperature higher than 915℃， due to the initiation of the solid side reaction between CaS and CaSO4， the percentage of CaS declined. In contrary， the percentages of CaO， H2 and CO increased possibly due to the consumption of part of CaSO4 in the side reaction and thus not enough lattice oxygen available. In the air reactor（AR）， the oxidization of CaS by air into CaSO4 was always dominant. Besides at ФAR below 0.8， both the solid side reaction of CaSO4 with CaS and the oxidization of CaS into CaO were simultaneously in effect.（ii） In the FR， the optimized condition was suggested as at around 915℃， atmospheric condition and carefully controlled ФFR around unity.（iii） In the AR， sufficient supply of air was important for the oxidization of CaS， and ФAR ≥1 would ensure the full oxidization of CaS into CaSO4 and prevent the emission of SO2 and formation of CaO as well. Overall， this study provided the most suitable conditions of using CaSO4 as OC in CLC of syngas with the minimal SO2 emissions and CaO formation.
Abstract: Oil was extracted from seeds of Jatropha Curcas, in high yields (up to 40% by weight). The extracted Jatropha oil was converted in a laboratory reactor to biodiesel by transesterification. Analysis of Jatropha oil and Jatropha biodiesel by GC/MS and GC/SIMDIS showed that Jatropha oil could be readily converted to a biodiesel product through NaOH catalyzed transesterification. The resulting biodiesel has desirable properties such as high cetane number and low flash point, which are major improvements over the properties of commercial biodiesel fuels.
Abstract: Pyrolysis and combustion characteristics of three different oil cakes such as Pongamia (Pongamia Pinnata), Madhuca (Madhuca Indica), and Jatropha (Jatropha curcas) were investigated in this study. The cellulose and lignin contents of oil cakes play very important role in pyrolysis and combustion processes. A kinetic investigation of three oil cakes was carried out and major part of the samples decomposed between 210℃ and 500℃. Pyrolysis and combustion were carried out with the mixtures of cellulose and lignin chemicals in different ratios and compared with the oil cakes. The biomass with higher cellulose content showed faster rate of pyrolysis than the biomass with higher lignin content. However at higher temperatures (>600℃) all the oil cakes exhibited similar conversion at low heating rate in N2 atmosphere. Apparent activation energies increased for Madhuca and Pongamia oil cakes indicating the presence of more cellulose whereas, low activation energy of Jatropha confirms more lignin content.
Abstract: Low toxicity reagents including n-hexane, dichloromethane, ethanol and mixed solvent were used in the separation of heavy oil. The heavy oil in which the asphaltene was removed was separated into saturated hydrocarbons, aromatics and nitrogen compounds before and after reactions. The optimized conditions of each step, and the data about each component before and after catalytic aquathermolysis of heavy oil by using GC-MS assisted with the 1HNMR and elemental analysis were obtained, and the changes of carbazole compounds in the resin were investigated. The results show that the nitrogen-containing groups are turned into some carbazole fragments. Meanwhile, the composition and structure of resin and asphaltene are changed. The supramolecular structure is damaged to some extent, generating two or three benzene rings and a number of small straight-chain hydrocarbons. These changes cause the viscosity reduction of heavy oil.
Abstract: The distribution of nickel and vanadium in the residue feedstock and various products obtained from fixed bed hydrotreating was investigated. The contents of nickel and vanadium in three fractions (low polar, polar, and strong polar) obtained under different temperatures and from various catalytic sections were determined. The results showed that the contents of nickel and vanadium in the residue feedstock are reduced significantly after hydrotreating. The removal ratios of nickel and vanadium at the base temperature reach 78.9% and 85.8%, respectively. Moreover, both the nickel and vanadium compounds are mainly removed by the protecting catalyst and demetalization catalyst. The contents of nickel and vanadium in low polar fractions are obviously affected by the hydrotreating process and reaction temperature; however, the contents of nickel and vanadium in strong polar fractions are less sensitive to these processing parameters.
Abstract: Silica-zirconia mixed oxide (SiO2-ZrO2) was synthesized by sol-gel method; with SiO2-ZrO2 as the support, CuCl2/SiO2-ZrO2 catalyst was then prepared by ion-exchange and used in the liquid oxidative carbonylation of methanol to dimethyl carbonate (DMC). The results showed that the introduction of zirconium species into the amorphous silica leads to the formation of Si-O-Zr bonds and Brnsted acid sites. When the CuCl2/SiO2-ZrO2 catalyst is calcined at 300℃~550℃ in an inert atmosphere, CuCl2 is dispersed and bounded on the surface of SiO2-ZrO2 support; CuCl2 can be auto-reduced to CuCl, which is then ion-exchanged with the surface Brnsted acid sites of the SiO2-ZrO2 support to form Cu+ species. As a result, most of copper remains to be highly dispersed on the surface of SiO2-ZrO2 and only a small amount of chlorine is left over. The CuCl2/SiO2-ZrO2 catalyst calcined at 450℃ exhibits excellent activity in the oxidative carbonylation of methanol; under the conditions of 140℃, 2.4MPa and a CO/O2 ratio of 2, the conversion of methanol and the selectivity to DMC reach 10.0% and 79.4%, respectively.
Abstract: A monolithic catalyst was prepared by loading C301/HZSM-5 on honeycomb ceramic with γ-Al2O3 coating. The prepared catalysts and the supports were characterized by SEM, XRD and BET methods. It was found that a thin uniform layer of C301/HZSM-5 was coated on honeycomb ceramic, thus the monolithic catalysts showed good structural and textual properties. A comparison study between the monolithic catalyst and C301/HZSM-5 particle/powderous catalyst for one step synthesis of dimethyl ether from syngas was carried out using a fixed-bed reactor. The results showed that CO conversion and DME selectivity on the monolithic catalyst were 79.62% and 70.58%, respectively, which were 7.78% and 9.44% higher than that on C301/HZSM-5 particle catalyst under the reaction conditions of 260℃, 4.0MPa and 1500mL/(g·h). Moreover, the monolithic catalyst kept high activity and high selectivity for 100h running, while remarkable deactivation was occurred on C301/HZSM-5 catalyst.
Abstract: A non-noble metal catalyst was prepared by loading cobalt and nickel on activated carbon through saturated impregnation; it was characterized by XRD, SEM and TPD and used in preferential oxidation of CO in H2-rich stream. The influence of water vapor and/or CO2 on the performance of this non-noble metal catalyst was also examined. The results indicted that NiO and finely dispersed Co3O4 are formed in the catalyst; the catalyst exhibits stronger adsorption ability to O2 than to CO2 and the adsorption ability to O2 increases with the loading of metal oxides. The non-noble metal catalyst exhibits high activity and selectivity in the preferential oxidation of CO. Over the catalyst CN250(35) with a metal oxide loading of 35%, CO concentration can be decreased to 40×10-6 at 433K~473K; meanwhile, the selectivity of O2 consumed by CO oxidation exceeds 50% at 473K. Moreover, the non-noble metal catalyst exhibits good resistance to water vapor and CO2 in the stream. These suggest that current catalyst may meet the requests in purification of H2 feed for PEMFC fuel cell application.
Abstract: A novel NOx-storage-reduction (NSR) catalyst of Pt/Ba/TiCeO was prepared by coprecipitation-impregnation method and the effects of the reaction atmosphere on its properties for NOx storage was investigated. The catalysts were characterized by means of N2 adsorption, X-ray diffraction (XRD) and temperature-programmed desorption(TPD). The results indicate that the specific surface areas of TiCeO and BaO/TiCeO were as high as 230m2/g and 90m2/g respectively. For the component of Ba, not only did it act as structural promoter for enhancing the structure stability of the catalysts Pt/Ba/TiCeO, but also it increased NOx storage capacity due to its basicity. Pt catalyzed oxidization of NO to NO2, and it is easier for NO2 to react with BaO/TiCeO to form nitrate than NO. TiCeO in Pt/Ba/TiCeO catalyst exhibited as both support and storage component in the NOx storage-reduction process. There were some active sites composed of Ba and TiCeO in the catalyst of Pt/Ba/TiCeO. The presence of SO2 has less effect on NOx storage capacity of Pt/Ba/TiCeO catalyst because the formed sulfate on the surface of the catalyst was unstable and was easily removed by reduction.
Abstract: The objective of this paper is to investigate COD removal efficiency of the Fischer-Tropsch-processing wastewater by applying the anaerobic moving-bed biofilm reactor (MBBR). The contribution of the anaerobic MBBR to total COD removal efficiency reached 97% at an organic loading rate (OLR) of 31.1g/(L·d). The COD removal efficiency of the anaerobic system had a slight decrease to 88% even though the feed OLR was increased to 39.7g/(L·d), and gradually decreased to 61% when feed OLR was increased to 56.3g/(L·d). The COD removal results in the anaerobic batch experiments of biofilm and sludge showed that the attached biofilm has higher activity than suspended sludge. The anaerobic MBBR system showed a characteristic of steady performance and resistance ability during the operation period.
Abstract: The disperse phase (methanol) droplet size of emulsified fuel has a significant effects on the combustion methanol-diesel oil emulsified fuel. The methanol droplet sauter mean diameter in methanol-diesel oil emulsified fuel was characterized with microphotography and arithmetic statistic method. Effects of rotor speed of disperser, emulsified time, additive amount and methanol content on the dispersity characteristics were investigated. The experimental results showed that the disperse phase (methanol) droplet size of emulsified fuel decreased with the augment of the rotor speed and additive amount, and almost contrary to the methanol content. The disperse becomes much better when emulsified time is 2min, rotor speed is 5×2800r/min, additive amount is 5% and methanol content is 10%, whose mean diameter is 16μm under experimental condition.
Abstract: Different from the traditional synthesis of methyl salicylate, the synthesis of methyl salicylate (MS) from salicylic acid (SA) and dimethyl carbonate (DMC) was carried out. The catalysts were a series of mesoporous aluminosilicate with different Si/Al mol ratio. The results showed that DMC was a good esterifying agent and mesoporous aluminosilicate was an effective catalyst for this esterification reaction. SA conversion and MS selectivity could reach 98.6% and 77.0% under suitable reaction condition. It was also found that both SA conversion and MS selectivity were closely related with Lewis acidity of the catalysts. In addition, the synergistic mechanism was proposed for the esterification of SA with DMC over mesoporous aluminosilicate.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
