Abstract: Coal from Naomaohu (NMH) in Xinjiang as raw material, hydroliquefaction experiments were performed in a batch high-pressure liquefaction reactor. Variations of free radical concentration of PAA and the intermediate products of hydroliquefaction with reaction residence time were examined with an EPR spectrometer. The results show that conversion rate of NMH coal hydroliquefaction first rises and then decreases. The maximum conversion rate and oil yield is 96.87% and 53.01% in 60 min. The free radical concentration of NMH is 2.6654×1018/g. PAA's free radical concentration ranges between 1.2519×1018/g and 1.9121×1018/g, which first increases and then decreases with increasing reaction time. As for the intermediate products, PAA, its free radical concentration could reflect extent of hydroliquefaction reaction, which has the same variation tendency with the oil yield. PAA's g value is between 2.00301 and 2.00403, which is lower than that of NMH (2.00434). In the process of hydroliquefaction, its g value first rises and then decreases, which is closely related with the heteroatom content of N, S, O in PAA and is consistent with the element analysis result.
Abstract: The char samples were prepared from pyrolysis/gasification of Shengli lignite in N2/O2/H2O/H2O+O2 atmosphere using a one-stage novel fluidized-bed/fixed-bed quartz reactor, and characterized by BET, Raman, FT-IR, microwave digestion ICP-AES, and TGA techniques. Effects of oxygen addition on gasification reaction and the char structure and reactivity were studied to investigate the activation and mechanism of O2 on the char. The results indicate that oxygen addition could change the char structure and improve the char reactivity, thus promoting gasification conversion and yield of H2 and CO2. The activation of O2 on the char mainly includes two aspects. First, with the decomposition of aromatic nucleus by oxygen, the large π bond of aromatic rings is destroyed, and the new functional groups are generated, which could promote the reaction (C+H2O→H2+CO). Second, with the gasification going on, the large (≥ 6 rings) aromatic structure is depolymerized into small (3-5 rings) one, and oxygen atoms enter the aromatic nucleus, forming the defect position C-O-C. As a result, the defect degree of char microcrystalline structure increases, the polymerization degree of char microcrystalline structure decreases, and the reactivity and surface adsorption of char is improved, which could promote the reaction (CO+H2O→H2+CO2).
Abstract: The influence of three additves (Kaolin, SiO2 and Al2O3) on sodium release and ash sintering temperature of high-alkali Zhundong coal with addition ratio range of 1%-5% was studied. The results indicate that the order of sodium capture efficiency for the additives is:Kaolin > SiO2 > Al2O3. The sodium capture efficiency increases with the addition ratio. However, the effect of temperature is much complex. At 600-1000℃, the sodium caputre efficiency of Kaolin increases firstly and then decreases, and the maximum value is achieved at 900℃. Meanwhile, the sodium capture efficiencies of other two additives decrease with increasing temperature. In addition, the ash sintering temperature of Zhundong coal is 803℃. After adding Kaolin, it decreases firstly and then increases with the addition ratio. At the addition ratio of 3%, the sintering tempeature is lowest due to the low-melting eutectic reaction between gehlenite and anorthite. SiO2 with 5% can increase the sinntering temperature to 879℃ sharply because of generation of diopside and its skeleton effect. The influence of Al2O3 on the sintering temperature is minimal.
Abstract: Vitrinite-rich Baishihu coal (BSR) was hydrothermally treated in an autoclave. FT-IR spectra peak fitting was used to investigate change of oxygen functional groups. Fixed bed was applied to pyrolysis of hydrothermal treated samples with and without separation of liquid waste, then contents of Na and Ca in these pyrolysis products were determined by atomic absorption spectrophotometer (AAS).The results show that moisture and chlorine content in Baishihu coal and Na2O content in ash decrease significantly after hydrothermal treatment. The hydrolysis of aryl ethers of Baishihu coal and the ion exchange reaction of carboxylate lead to increase of hydrogen content and H/C atomic ratio, promoting increase of tar yield during pyrolysis. The organic Ca can be removed by hydrothermal treatment at 300℃ and is separated with the hydrothermal liquid waste. Because of catalysis of inorganic elements such as sodium and calcium in hydrothermal liquid on coal pyrolysis, the hydrothermal treated samples without separation of liquid waste has higher gas yield and lower tar yield than those with separation of liquid waste. Na content and distribution in pyrolysis products of BSR and treated samples decease as:char > water > tar > gas, while the order of Ca is:char > tar > water > gas. As the hydrothermally treated temperature increases, the released content of sodium and calcium during pyrolysis process decreases. The released Na during pyrolysis mainly distributes in water, followed by tar, while Ca is just opposite.
Abstract: The bio-oils from ordinary condensation and from fractional condensation were analyzed by GC-MS. Comparing the relative peak areas of these, the result shows that the fractional condensation has an obvious effect on component enrichment. The acetic acid in the 4th step condensation increases from 5.38% to 9.44%, the guaiacol in the 2nd step condensation increases from 3.46% to 6.23%, and the sringol and isoeugenol in the 1st step condensation increase from 1.48% to 4.44% and from 5.52% to 17.84%, respectively. After 75 days' storage stability experiment on the physicochemical properties of multi-fraction bio-oils obtained from fractional condensation in a 15℃ constant temperature and humidity box, the water content of the fractional bio-oils increases by 1.58%, 1.88%, 1.80% and 2.43%, respectively. Besides, the acids, aldehydes, ketones and alcohols decrease after storage because light components are consumed by chemical reaction. The relative peak areas of phenols increases slightly. It suggests that the chemical reactions in the bio-oil from 1st and 2nd step condensations can be negligible, while the chemical reactions in the bio-oil from 3rd and 4th step condensations are active. Organics in bio-oils can be classified by the analysis of GC-MS both before and after storage for analyzing the kinds and intensities of the chemical reactions in bio-oils.
Abstract: MCM-41 and Zr-MCM-41 with different initial n(Si)/n(Zr) ratios were synthesized by hydrothermal method. Mo2N/Zr-MCM-41 hydrodeoxygenation catalysts were prepared by (NH4)6Mo7O24 carrier co-impregnation, calaination, temperature programing and nitridation, and characterized by XRD, XPS, TEM and Py-FTIR methods. The catalytic performance of Mo2N/Zr-MCM-41 in hydrodeoxygenation of Jatropha curcas oil was evaluated in a high pressure reactor. The results indicate that Zr modified carrier has the same pore structure as pure silicon MCM-41, and the value of L acid and B acid increases. As the active component, the Mo2N has an excellent HDO performance. Under the reaction temperature of 350℃ and the hydrogen pressure of 3.0 MPa, the catalyzed product oil is mainly composed of straight chain alkanes and aromatic compounds, accounting for more than 90% of the product components. The deoxygenation rates of the new catalysts with different n(Si)/n(Zr) ratios are all above 98%, and the content of aromatic compounds is higher than that of straight chain alkanes, which accounts for 72.09% of the total composition. The aromatic compounds are mainly single ring and bicyclic aromatic hydrocarbons with the length of carbon chain of C8-16. After the leprosy oils catalyzed by Mo2N/Zr-MCM-41 are fractionated, it can be prepared to be biofuels.
Abstract: Perovskites as host structures of cations were used in order to generate in situ active and stable catalysts for ethanol steam reforming. For this purpose, La1-xMgxAl1-yNiyO3 (x=0.1; y=0, 0.1, 0.2, 0.3) perovskites were synthetized by the citrate method. Ni segregation is evident for a substitution level higher than 0.2. The segregation of Ni as NiO generated species interacts with different metal-support after the reduction step. The y=0.1 catalyst presents the highest H2 yield value about 85% during reaction time, with low mean values of CH4 and CO selectivities of 3.4% and 11%, respectively and a low carbon formation. The better performance of y=0.1 catalyst could be attributed to the minor proportion of segregated phases, thus a controlled expulsion of Ni is successfully reached.
Abstract: A series of Fe/MgO catalysts with well-defined exposed crystal planes were synthesized by impregnation, deposition-precipitation and ultrasonic impregnation methods. The catalysts were characterized by X-ray powder diffraction, high-resolution transmission electron microscopy, CO2 temperature-programmed desorption, H2 temperature-programmed reduction, X-ray spectroscopy and N2 adsorption-desorption isotherms. The characterization results indicate that the basicity of MgO supports strongly affect the catalytic performance of iron-based catalysts for Fischer-Tropsch synthesis. It is found that the strong basicity sites of MgO supports remain during the ultrasonic impregnation process. The intrinsic basicity of Fe/MgO catalysts enhances dissociative CO adsorption and promotes the olefin selectivity. In addition, the catalyst of iron particles on the (111) crystal planes of MgO nanosheets presents higher TOF value and olefins selectivity than that of the catalyst using the (100) crystal planes of MgO nanocubes as a support. The effect of basic properties of MgO nanocrystals facilitates CO chemisorption, suppressing H2 adsorption and olefin desorption on the corresponding Fe/MgO catalysts.
Abstract: Zn2.4Ni0.6AlxFe1-xO4.5±δ catalysts were prepared by co-precipitation, tested in auto-thermal reforming (ATR) of HAc, and characterized by XRD, H2-TPR, BET and XPS. The result showed that the Zn2.4Ni0.6Al0.5Fe0.5O4.5±δ catalyst presented a better performance in ATR of HAc. The HAc conversion and hydrogen yield remained at 100% and 2.39 mol-H2/mol-HAc, respectively. The characterization results indicated that the better performance can be attributed to the addition of Fe, which was helpful to increase surface area and formation of FeNiZn alloy after reduction, while resistance to oxidation and coking was improved as well.
Abstract: Monoclinic WO3 was successfully synthesized by the hydrothermal method using sodium tungstate as tungsten source, nitric acid as acid source, and citric acid (tartaric acid) as surfactant. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet-visible diffuse reflectance (UV-vis-DR), and Brunner-Emmet-Teller (BET) were employed to characterize the structure and morphology of WO3. The effects of molar ratios of nitric acid and citric acid (tartaric acid) to tungsten atoms on crystal phases and morphologies of WO3 were investigated in detail. The results indicated that large amounts of nitric acid and addition of hydroxyl acids were found favorable for the formation of monoclinic WO3. Monoclinic WO3 was achieved under suitable conditions of molar ratios of nitric acid to tungsten atom of 2.8:1 and hydroxyl acids to tungsten atom of 0.8:1. The WO3 was coupled with p-type semiconductor CuCrO2 to fabricate the CuCrO2-WO3 composite photocatalyst. It was used for hydrogen production from photocatalytic decomposition of water. The monoclinic WO3 with high crystalline perfection exhibited better photocatalytic properties.
Abstract: The Cl-V2O5-WO3/TiO2 catalysts were prepared by impregnation methods. With the Cl ions content increased from 0 to 2.5%, the NO conversion of Cl-V2O5-WO3/TiO2 catalysts increased at first and then decreased. Combined with the experimental results, 1.5% Cl-V2O5-WO3/TiO2 catalyst was the optimal catalyst, NO conversion was higher than 95% in the range of 149-362℃, and NO conversion was higher than 90% in the temperature range of 145-385℃. The catalysts were characterized by XRF, BET, XRD, TG, FT-IR and H2-TPR. The specific surface area and pore volume of the catalysts decreased in different degrees after adding SO2 and H2O in reactant gas. The poisoned catalysts deposited sulfur species and contained NH4+ and SO42-. Adding appropriate amount of Cl ions inhibited the formation of side byproducts and enhanced the poisoning resistance of V2O5-WO3/TiO2 catalyst.
Abstract: A series of cobalt-based spinel composite metal oxides doped with alkaline earth metals, viz., MxCo3-xO4 (M=Mg, Ca, Sr and Ba; x=0, 0.1, 0.3, 0.5, 0.7 and 0.9), were prepared by the coprecipitation method and characterized by XRD, SEM, nitrogen sorption, H2-TPR, O2-TPD-MS and XPS; the effect of alkaline earth metal doping on the catalytic performance of MxCo3-xO4 composites in N2O decomposition was investigated in a fixed bed micro-reactor. The results showed that after doping with the alkaline earth metals, the particle size of MxCo3-xO4 catalysts is decreased, accompanying with an increase in the specific surface area and the amount of surface adsorbed oxygen and Co2+ species. Meanwhile, the redox performance and catalytic activity of MxCo3-xO4 in N2O decomposition are also greatly enhanced. Under the conditions of 0.68% N2O, 3% O2 and Ar as balance gas, the Sr0.7Co2.3O4 catalyst doped with Sr (x=0.7) exhibits highest activity in N2O decomposition; the reaction temperatures where the N2O conversion reaches 10% and 95% are as low as 312 and 451℃, respectively.
Abstract: The interaction between 1-butyl-3-methylimidazolium hydrosulphates ionic liquid ([Bmim]HSO4) and nitrogenous compounds (quinoline and indole) were investigated by density functional theory, and analyzed by NBO and AIM methods. The most stable structure of [Bmim]HSO4 ionic pair displays a strong hydrogen bond interaction between O atom in [HSO4]- anion and C14-H20 in imidazolium ring. NBO and AIM analysis at the molecular level proves that there is a strong interaction between quinoline or indole and the anion of [Bmim]HSO4. The strong interaction between the active hydrogen of [HSO4]- and the N atom of quinoline molecule as well as the hydrogen bond formed between the H atom of N-H in indole molecule and the O atom of [HSO4]- are the main driving force for denitrogenation performance of [Bmim]HSO4.
Abstract: The attapulgite (Atp) widely existed in nature could be modified by magnetism, and a magnetic attapulgite (MAtp) modified by magnetic iron oxide was prepared by deposition-precipitation method. The physical and chemical properties of the magnetic attapulgite were analyzed by BET, VSM, XRD and SEM, and the effects of iron oxide content, reaction temperature and flue gas composition on the mercury removal capacity were studied. The results show that the removal ability for Hg0 is enhanced by the combination of Atp and magnetic materials, and the removal ability of MAtp is gradually improved with the increase in iron oxide content. Moreover, the removal ability of Hg0 is enhanced with the increase of temperature in the test temperature range, and the chemical adsorption of Hg0 is a main factor for MAtp. The addition of O2 and NO is beneficial to the removal of Hg0, but the Hg0 penetration rate does not change significantly with the concentration; while SO2 inhibits the removal of mercury, and the inhibition effect is more obvious with the increase of concentration. However, when NO and SO2 coexist, NO can greatly weaken the inhibition effect of SO2 on mercury removal.
Abstract: To understand the enrichment characteristics of trace As in fly ash, the adsorption mechanism of AsO, a typical arsenic oxide, in SiO2, the main component of fly ash, was investigated by using density functional theory; energy calculation, AIM theory, Mulliken charge analysis and Localized Orbital Locator(LOL) color map were performed on the optimized adsorption configuration, in order to analyze the interaction between AsO and SiO2. The results show that the adsorption energy of AsO on the defect sites of amorphous SiO2 is higher than 50 kJ/mol, typical for the configuration of chemical adsorption. The bonds of As-Si, Si-O and As-O formed at the active defect sites of the amorphous SiO2 have high strength, belonging to the covalent bond; that is, the interaction between SiO2 and AsO is covalent.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
