Abstract: The influences of temperature, time, and mineral matter on conversion of lignite in a semi-continuous supercritical water reactor (SCWR) were investigated. The evolution of pore during reaction in SCWR was deduced with Fourier transform infrared and Raman spectra characterization. It is found that supercritical water can quickly extract the volatile from coal under low temperature, which promotes char graphitization and formation of carbon precursor. When temperature is above 550 ℃, more C-O-C cross-linking structures are formed, accompanied by a significant increase of surface area. The extraction yield of deashed coal is relatively high during pyrolysis process and more micropores are formed compared with raw coal. Furthermore, mineral matter in coal promotes the formation of mesopore.
Abstract: Modification of low rank coal by thermal treatment is the key to its high-efficiency conversion and utilization. In this paper, the thermal treatment and hydrothermal treatment of Xianfeng lignite were carried out. By combination of the characterizations of structure and properties of treated coals, the modification of thermal treatment and the interaction of water in the hydrothermal process were investigated. The results indicate that the disassociation of non-covalent bonds and the pyrolysis of weak covalent bonds dominate in the treatment process below the pyrolystic temperature of lignite. The hydrothermal reaction can inhibit the pyrolysis of coal matrix and the release of small molecular compounds in the process of hydrothermal treatment. At higher than the pyrolysis of lignite, the thermal treatment shows obvious pyrolysis and deoxygenation. The hydrothermal reaction can provide active hydrogen to stabilize the pyrolysis fragment and avoid the secondary pyrolysis and condensation, so that the extraction and swelling properties of hydrothermal treated coal in mixed solvent were improve at certain extent.
Abstract: The Influence of calcium oxide on Shengli lignite char microstructure and steam gasification performance was studied. Demineralized coal samples were loaded with different content of calcium oxide and then pyrolyzed at 1 100 ℃. The char is gasified with steam in a micro fixed-bed reactor. The X-ray diffraction apparatus and Raman spectra apparatus were used to characterize the structure of coal char. The results show that the char with 5% calcium exhibits the highest gasification reactivity, while the catalysis for the steam gasification of char with 2% calcium is almost negligible. The results of XRD suggest that calcium can effectively hinder the carbon graphitization in the process of pyrolysis. The intensity of (002) and (100) peaks of char decreases with the rise of calcium loading. With the increase of calcium loading, the aromaticity fa is reduced from 66.8% to 39.9%. Raman spectra results show that ID/IG increases from 1.363 to 1.541 and IG/Iall reduces from 0.423 to 0.394 with the increase of calcium loading, respectively. It means that the decomposition of large polyaromatic ring structure in coal is greatly enhanced by the catalytic action of calcium, and the disordering degree and the structural defects of char increase with the increase of calcium loading.
Abstract: The common clay mineral of kaolin was selected as an additive into Zhundong coal during combustion. Sodium retention rates and coal ash fusion temperatures were investigated at different blending ratios and temperatures. XRD and ternary phase diagram were used to identify mineral transformations at high temperatures. The results show that the sodium retention rates increase rapidly with blending ratio from 0~2%, slowly from 2%~5% and decrease slightly with increasing temperature. The ash fusion temperatures of coal blended with additive initially decrease slowly, then decrease rapidly and finally increase with increasing blending ratio, reaching about 1 200 ℃ at 3%. The results of XRD and ternary phase diagram analysis show that the change of ash fusion temperature is due to the mineral content changes of rankinite, gehlenite and anorthite. The lowest ash fusion temperatures at the blending ratios of 3%and 4% are mainly caused by the low temperature eutectic phenomenon. The sodium retention rate reaches more than 60% and ash fusion temperature reaches about 1 300 ℃ at blending ratio of 2%, which is conductive to solid-state slag-tap boiler. The ash fusion temperature is about 1 200 ℃ at blending ratio of 3.0~4.0%, which is suitable for liquid-state slag-tap boiler.
Abstract: The modified asphalt was prepared via adding tetrahydrofuran soluble fraction of direct coal liquefaction residue (THFS) as modifier and benzaldehyde as crosslinking agent. Modification conditions such as mixing temperature, ratio of THFS and crosslinking agent to asphalt were studied. The optimal conditions are mixing temperature of 170 ℃, and THFS to asphalt ratio of 4%. The modified asphalt can get the better properties by using crosslinking agent. Characterizations of modified asphalt were analyzed by TG-FTIR, FT-IR and fluorescence microscope. Comparing with other asphalt the weight loss of modified asphalt which added benzaldehyde as crosslinking agent is lower. The modified asphalt with benzaldehyde as crosslinking agent has less CH4 release than other samples and CH4 was released at higher temperature. The involvement of benzaldehyde significantly enhances the stretching vibration of aliphatics (-CH2-) of modified asphalt at 2 924 and 2 854 cm-1 as well as the transmittance of the absorption peaks at 872, 810 and 746 cm-1 representing benzene substituent, and a new absorption peak at 1 060 cm-1 assigned to C-O-C stretching vibration. Moreover the new modified particle in the fluorescence microscope images indicates that the involvement of cross-linking agent may cause polycondensation of THFS and the matrix asphalt.
Abstract: The DCLR and TLA content are 5%, 10%, 15% and 20% by mass of SK-90 base asphalt respectively. The properties and microstructures of DCLR and TLA blending modified asphalts are tested by SHRP PG, penetration system, infrared spectrometer and gel permeation chromatograph. It indicates that adding DCLR and TLA can improve the high-temperature properties of asphalts, but the low-temperature and fatigue resistance of asphalts are declined. Based on the functional group and molecular weight distribution of asphalts, it predicts that the physical modification be happened in the DCLR and TLA blending modified asphalt. Meanwhile, the DCLR cannot replace TLA totally.
Abstract: To improve the knowledge about pyrolysis behavior of reed black liquor, pyrolysis experiments were carried out at 530, 580, 630, 680, 730 and 780 ℃ in fluidized bed under atmospheric N2. Effects of bed temperature on yields of gas product, carbon conversion, emission of NOx and SO2, characterization of tar, and micro-morphology of pyrolysis char were examined. The results show that the main components of gaseous product are CO, CH4, CO2 and H2. The volume percentage of H2 and CO increases with increasing bed temperature, but that of CH4 and CO2 is opposite. In addition, with increasing temperature the concentration of combustible gases increases from 59.2% at 530 ℃ to 66.1% at 780 ℃. The yield of tar decreases with increasing temperature. The relative content of polycyclic aromatic hydrocarbons is 46.88% at 780 ℃, which is the maximum among six bed temperatures.
Abstract: With attapulgite clay (APT) as support, the Pd-Cu/APT catalysts were prepared by an ammonia evaporation method and characterized by N2-physisorption, XRD, FT-IR, TEM and H2-TPR. The effect of ammonia concentration on the catalytic performance of Pd-Cu/APT in CO oxidation at room temperature was investigated in a fixed-bed continuous flow microreactor. The results showed that CuO appears as the main Cu species in the Pd-Cu/APT catalysts prepared with over low or over high ammonia concentration, whereas the quantity of Cu2(OH)3Cl phase is much less. However, a proper concentration of ammonia is of benefits to forming stable Cu2(OH)3Cl species in Pd-Cu/APT; owing to its high dispersion, nano-platelet morphology and strong interaction with Pd species, the presence of stable Cu2(OH)3Cl can significantly promote the catalytic performance of Pd-Cu/APT in CO oxidation. Under a gas hourly space velocity (GHSV) of 6 000 h-1 for a feed stream containing 1.5% CO and 3.3% water, the Pd-Cu/APT catalyst exhibits excellent activity and stability in CO oxidation even at room temperature.
Abstract: To investigate the catalytic performance of nickel-based catalysts for carbon dioxide reforming of methane, four samples, SCM, IMP, T310 and HTP, with same contents of Ni were prepared by solution combustion method, incipient-wetness impregnation method, colloid mill circulating impregnation method and hydrothermal-precipitation method. The catalytic performance was tested at 800 ℃. The samples were characterized with ICP-AES, N2 absorption-desorption method, XRD, H2-TPR and TEM techniques. It was shown that the preparation methods had significant effects on the catalytic performance. The HTP and T310 samples had larger specific surface area, 190.83 m2/g and 182.21 m2/g respectively, which could provide more active sites and improve the activity (the initial conversion of CH4 and CO2 of HTP was up to 85.15% and 90.84%). The reduction peak area of NiAl2O4 of the catalysts prepared by solution combustion method and incipient-wetness impregnation method was higher than 90% of the total reduction area, indicating that these catalysts had more small Ni size particles and better stability after reduction (the conversion of CH4 for SCM and IMP was higher than that of HTP and T310 after 50 h experiment, and was up to 50% after 100 h reaction). Hence, the mojor reason for improving the activity and stability of catalyst would be the size of Ni particles and its resistance to sintering.
Abstract: Microbial fuel cells (MFCs) represent a new approach for treating waste water along with electricity production. The present study addressed electricity production from domestic wastewater using a mediator-less double chamber MFC. The electricity production was monitored under different operational conditions for both summer and winter samples. Optimization of the anodic and cathodic chambers resulted in a maximal current of 0.784 and 0.645 mA with the maximal power intensity of 209 and 117 mW/m2 in power duration of 24 h for the summer and winter samples, respectively. Scanning electron microscopy showed that the bacterial biofilm formation on the anode was denser for the summer sample than that when the winter sample was used, so was the total bacterial count. Therefore, samples taken during summer were considered better in electricity production and waste water treatment than those taken during winter basically because of the high microbial load during the hot season. In parallel, there was a decrease in both biological oxygen demand (BOD5) and chemical oxygen demand (COD) values which reached 71.8% and 72.85%, respectively at the end of the operation process for the summer sample, while there was no evident decrease for the winter sample. Optimizing the operating conditions not only increased the potential of using domestic waste water in microbial fuel cells to produce electricity, but also improved the quality of the domestic waste water.
Abstract: A direct carbon fuel cell (DCFC) was assembled with yttria stabilized zirconia (YSZ) as electrolyte and active carbon (AC), graphite (G) and semi-coke (SC) were employed as the DCFC fuels. The influences of the carbon fuel pore structure and reactivity, operation temperature, anode atmosphere on the anode reaction were investigated. The results indicated that for three carbonaceous fuels, the performance of DCFC is in the order of AC > SC > G, the same as that for their oxidation reactivity in air or CO2 atmosphere. The reactivity of carbonaceous fuels is determined by their surface oxygenic functional groups and pore structure. Moreover, the results revealed that the DCFC anodic reactions involves the oxidation of C to CO2, the conversion of CO2 to CO via the reverse Boudouard reaction, and the oxidation of CO to CO2.
Abstract: A series of Co/MOR catalysts were prepared by impregnation method and used in the selective catalytic reduction of nitric oxide with methane (CH4-SCR). These catalysts were characterized by XRD, BET, TG-MS, H2-TPR, NH3-TPD and NO-TPD; their performance in the CH4-SCR of NO was investigated. The results showed that cobalt species exist as Co3O4 spinal in the Co/MOR catalysts; the acidity and redox and NO absorption/desorption ability of the Co/MOR catalysts are changed after the incorporation of cobalt in MOR zeolite, in comparison with pure MOR zeolite. The catalytic performance of Co/MOR is closely related to its redox and NO adsorption/desorption ability, which are dependent on the cobalt loading. The Co(10)/MOR catalyst with a cobalt loading of 10% exhibits high activity in the CH4-SCR of NO; over it the conversion of nitric oxide reaches 54.2% at 330 ℃.
Abstract: Ionic liquid [BIm]Cl/CuCl was synthesized by two-step synthesis using 1-butylimidazole, HCl and CuCl as raw materials. Structure of [BIm]Cl/CuCl was characterized by FT-IR and FT-ICR MS. The interactions between [BIm]Cl/CuCl and thiol were analyzed by DSC, FT-IR and UV-vis spectra. The mechanism for the adsorption removal of thiol by [BIm]Cl/CuCl was discussed. It was found that the sulfur content in methyl tert-butyl ether (MTBE) could be reduced to lower than 5 μg/g via adsorptive distillation desulfurization process with [BIm]Cl/CuCl as adsorbent, and that significant deterioration in the desulfurization efficiency of adsorbent was not observed in a few recycling tests.
Abstract: A core-shell structured Pd-Co3O4@SiO2 catalyst was prepared by a simple self-assemble method and used in lean methane combustion. The results of catalytic tests indicate that the core-shell Pd-Co3O4@SiO2 catalyst exhibits high activity in lean methane combustion and superior stability at high temperature. The results of TEM, XRD, and H2-TPR characterization suggest that the high activity of Pd-Co3O4@SiO2 is mainly ascribed to the strong interaction between CoOx and PdO species inside the SiO2 shell. Meanwhile, as the active Pd and CoOx species in Pd-Co3O4@SiO2 are enshielded in the core-shell structure, which is effective to protect the active phase from sintering at high temperature, the core-shell structured Pd-Co3O4@SiO2 catalyst is thus far superior in thermal stability against high temperature to the supported Pd/Co3O4@SiO2 and Pd/Co3O4-SiO2 catalysts.
Abstract: The Ni2P-L, Pr-Ni2P-L and Ce-Ni2P-L catalysts were prepared by thermal decomposition of hypophosphites and reduced at low temperature; they were characterized by X-ray diffraction (XRD), temperature programmed reduction with hydrogen (H2-TPR), nitrogen physisorption, CO adsorption, and X-ray photoelectron spectroscopy (XPS). The effect of the rare earth praseodymium (Pr) or cerium (Ce) elements on the activity of Ni2P-L catalyst in hydrodesulfurization (HDS) was investigated with dibenzothiophene (DBT) as a model compound. The results indicated that the addition of Pr and Ce can suppress the formation of Ni5P4 and other mixed crystal phases and then promote the formation of Ni2P phase. After adding the rare earth metals, the selectivity to BP over the Ni2P catalyst is enhanced greatly, though the total HDS activity is decreased slightly.
Abstract: Ultrasound-assisted wet impregnation method was used to prepare the Fe2O3/γ-Al2O3 sorbent. The effects of the precursor solution content, carrier size, adsorption temperature and atmosphere on the arsenic capture efficiency in a fixed-bed reactor were investigated. The results show that the precursor solution concentration and the size of carrier can affect the arsenic adsorption efficiency. The increasing of adsorption temperature enhances the chemical adsorption ability. However, the efficiency will be decreased if the temperature is over 600 ℃. The addition of SO2 in the atmosphere will enhance the arsenic adsorption ability of Fe2O3/γ-Al2O3. The influence of NO on the capture efficiency is not significant during this study.
Abstract: The activated carbon supported copper-based catalyst was prepared by deposition-precipitation method and used to catalyze the direct vapor-phase oxycarbonylation of methanol to dimethyl carbonate (DMC). The effect of preparation conditions(such as copper salt, reductant, precipitant and loading amount ect) on the catalytic performance were investigated by XRD, H2-TPR and SEM techniques. The result showed that under the condition of MeOH/CO/O2(volume ratio)=5:11:1, SV=6 625 h-1, Cu2O /AC catalyst (Cu(CH3COO)2·H2O as precursor, glucose as reductant, Cu2O loading amount of 17.1%) showed satisfactory catalytic performance for DMC synthesis. The STY reached 99.36 mg/(g·h) and the selectivity of DMC was about 83.13%.
Abstract: A series of ZSM-5-SBA-15 composite molecular sieves were prepared by post-synthesis method and characterized by XRD, FT-IR, BET, NH3-TPD and pyridine infrared. The results indicated that ZSM-5-SBA-15 has both ZSM-5 microporous and SBA-15 mesoporous structure. The adsorption-desorption measurement using pyridine and ammonia demonstrated that acidity of SBA-15 was heightened because ZSM-5 was introduced into. Compared with ZSM-5, the acidic sites on ZSM-5-SBA-15 were still accessible. However, the strength of acidity was weakened. In the probe reaction of the alkylation of toluene and methanol, the ZSM-5-SBA-15 composite exhibited higher para-xylene selectivity in comparison to pristine ZSM-5.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
