Abstract: Shenmu char powder (SCP) was sequentially extracted with petroleum ether, carbon disulfide, dichloromethane, acetone, and methanol in a Soxhlet extractor to obtain extracts 1-5 (E1-5) and final residue. The total extract yield of SCP is 1.76%. All the extracts were characterized with gas chromatograph/mass spectrometer (GC/MS), atmospheric solid analysis probe/time-of-flight mass spectrometer (ASAP/TOF-MS), and electrospray ionization/time-of-flight mass spectrometer (ESI/TOF-MS). Normal alkanes with C15 to C24 and arenes with 3 and 4 rings are predominant in E1 and E2, respectively, while more heteroatom-containing organic species were identified in E3-5. Organooxygen compounds are the most abundant in E4 and E5 based on analysis with GC/MS. Much more heteroatom-containing organic compounds were detected in E3-5 with ASAP/TOF-MS and ESI/TOF-MS than with GC/MS.
Abstract: The isopropanolysis of lignite model compound was investigated using the density functional theory method. Firstly, thermodynamic properties were estimated. Secondly, the method combined the Hirshfeld population and the Fukui function was proposed to obtain the initial reactant configuration. Thirdly, the Linear Synchronous Transit method combined with the Quadratic Synchronous Transit method was developed to calculate the reaction pathway and simultaneously optimize the structures of reactant and product. It was observed that the calculated enthalpy was decreased with increasing temperature. Furthermore, the nucleophilic group was discovered. Moreover, it was proved that the isopropanol was the most active among the common alcohols, indicating that the isopropanolysis was exothermic and nucleophilic.
Abstract: Thermal dissolution behaviors of Shengli (SL) and Xiaolongtan (XLT) lignite in methanol were investigated. The composition and structural characteristics of soluble portions (SPs) obtained at 320 ℃ were characterized with Fourier transform infrared spectroscopy, gas chromatograph /mass spectrometer (GC/MS) and atmospheric solid analysis probe/time of flight mass spectrometer (ASAP/TOF-MS). For the two lignites, the yield of SPs increase with temperature increasing, while the yield of SPs from XLT (SPXLT) is obvious higher than that from SL (SPSL) above 240 ℃. GC/MS analysis results show that compounds in the SPs are dominated in oxygen-containing organic species, especially the relative content of phenols is higher than 49%. The relative contents of alkenes, arenes, ethers, carboxylic acids, esters, organosulfur compounds (OSCs) in SPSL are higher, while the relative contents of alkanes, phenols, ketones and organonitrogen compounds in SPSL are lower than those in SPXLT. Additionally, the OSCs in SPSL and SPXLT are mainly composed of thiophenes and mercaptan, respectively. Many compounds with high polarity and low volatility which could not be identified by GC/MS were identified using ASAP/TOF-MS. The relative contents of CHO and CHS class species in SPSL are higher, but the relative contents of CHN, CHNO, CHOS, CHNS and CHNOS in SPSL are lower than those in SPXLT. The carbon number and double bond equivalent (DBE) of the compounds in SPSL and SPXLT mainly distribute in 0-10 and 3-15, respectively, while the distribution of carbon number and DBE of the compound in SPXLT are more concentrated than those in SPSL.
Abstract: Zhaotong lignite from Yunnan province was hydrothermally upgraded at 150-300 ℃, then the changes of surface oxygen-containing groups were analyzed by Fourier transform infrared spectroscopy, and the evolution of pore structure was identified by nitrogen adsorption isotherm. Constant temperature and humidity incubator were used to investigate moisture readsorption characteristics. The results indicate that the main hydrophilic oxygen-containing functional groups (-OH, -COOH, >C=O) decrease and are removed effectively with increase of upgrading temperature. Large changes occur in pore structures of the treated coal, in which the specific surface area and total pore volume increase firstly then decrease with increasing temperature, moreover tar initially generate at 250-300 ℃. Moisture readsorption performance is restrained effectively under the synergy effect of physical and chemical structures, and the moisture readsorption ratio decreases continuously with increase of upgrading temperature. Environment humidity is a key factor affecting moisture readsorption considering storage of the upgraded lignite. Therefore the situation of hydrothermal upgrading at high temperature and storage at low temperature and low humidity could be more advantageous in terms of enhancing efficiency of lignite upgrading.
Abstract: The distributions of light aromatic hydrocarbons in the gaseous tar were investigated upon upgrading over Mo and Ni-modified HZSM-5 catalysts during coal pyrolysis. The results show that the yield of light aromatic hydrocarbon from lignite (XM) pyrolysis is increased by 220% after the cracking of gaseous tar over HZSM-5 zeolite, due to the aromatization of olefins or alkanes and the dehydroxylation of phenols. The loading of Mo and Ni on HZSM-5 is able to enhance the formation of light aromatic hydrocarbons; Ni can obviously promote the side chain cracking, whereas Mo is more effective for the formation of aromatic compounds with side chains such as toluene and xylene. Without catalysts, the yield of light aromatic hydrocarbons from coking coal (FX) pyrolysis is about 2.2 and 2.4 times higher than that from XM and bituminous coal (PS) pyrolysis, respectively. By using catalysts, however, the yield of light aromatic hydrocarbons from XM pyrolysis is obviously higher than that from PS pyrolysis and close to that from FX pyrolysis, as XM is provided with abundant oxygen containing functional group and aliphatic structure that can be transformed to light aromatic hydrocarbons over the HZSM-5 catalysts.
Abstract: The direct liquefaction oil from Shenfu coal and the refined oil through hydrofining were cut into different fractions by true boiling point distillation and the sulfur and nitrogen compounds in each fraction were analyzed by GC-PFPD and GC-NCD; the change in the sulfur and nitrogen compounds in the direct liquefaction oil upon the hydrofining process was then investigated. The results illustrated that the sulfur content in the direct liquefaction oil takes a 'U' type distribution with the distillation range from low to high boiling point, whereas the content of nitrogen is far higher than that of sulfur, which increases with the rising of the fraction boiling point. After hydrofining, the sulfur and nitrogen contents are removed by 97% and 98.9%, respectively. Bicyclic and tricyclic compounds such as benzothiophene and dibenzothiophene account for 93.25% of the sulfur compounds in the coal liquefaction oil; after the hydrofining, low boiling point sulfur compounds such as mercaptan, sulfoether and thiophene almost disappear, with benzothiophene and dibenzothiophene as the main sulfur compounds that are difficult to remove. In the coal liquefaction oil, five-membered heterocycle neutral compounds account for 54.96% nitrogen and the portion of basic nitrogen compounds, including mainly anilines with a relatively small amount of quinolones, is 23.22%. After hydrofining, fatty amines are removed completely and the residual nitrogen in the refined oil exists mainly as the basic nitrogen compounds such as quinolones and anilines.
Abstract: The char fines from fluidized bed gasification (fines for short) are classified into 7 components based on particle size. The basic physicochemical properties, the constant and programmed increasing temperature CO2 gasification behaviors were investigated by coal quality analyzer, elemental analyzer, X-ray powder diffractometer, gas sorption analyzer and thermogravimetric analyzer. The difference of gasification reactivity and its reasons were discussed. The results show that after partial gasification, fixed carbon of the fines is higher than that of its parent coal but lower than the corresponding coal char because of the escape of volatiles. The particle size distribution of fines is very wide and multimodal distribution with the shape of "M". In addition, the ash content of fines approximately increases with decreasing particle size. However, the carbon content decreases with decreasing particle size. Both the constant and programmed increasing temperature CO2 gasification show the same result. The gasification reactivity firstly decreases and then gradually increases with decreasing particle size. Furthermore, the carbon crystalline structure and ash content are contributed to the difference in gasification reactivity of fines, and the different reactivity is not related to the pore structure in this experimental condition.
Abstract: The hydropyrolysis of organic matters was comparatively conducted over various catalysts including ZnCl2, NiCl2, Fe2O3, NaY and MoS2 and the reaction mechanisms over different catalysts were then investigated. The results indicate that the yield and composition of liquid products from hydropyrolysis are related to the type of catalyst, though various catalysts do not have significant difference in the product biomarker parameters. Meanwhile, for the organic matters with different maturities and types, various catalysts are also quite different in their actual performance. The element analysis, infrared spectra and X-ray diffractograms of the solid residues illustrate that various catalysts are obviously different in the catalytic reaction mechanism. In comparison with NiCl2, mass transfer is an important factor in the ZnCl2 system, besides the catalytic cracking and catalytic hydrogenation. With Fe2O3 as the catalyst, the formation of H free radical by the adsorption of H2 at the surface active O sites may promote the hydrogenation of organic matters. MoS2 as the catalyst may involve two mechanisms, viz., the hydrogenation over transition metal Mo and the initiation of free radicals from H2S intermediates.
Abstract: The crude fat was used as raw material, which was extracted from Nannochloropsis sp. by acid hydrolyzation. The pyrolysis characteristic of crude fat and its effect on the yield of each phase and the properties of bio-oil were examined at different temperatures in a bench-scale fixed bed reactor. In addition, the thermogravimetric characteristics of crude fat and all components were studied by means of thermogravimetric analyzer, and corresponding kinetic parameters were determined. The results show that both the yield of organic phase and the properties of bio-oil which is produced from the pyrolysis of all components are enhanced by the pyrolysis of fat. Moreover, with an increase in temperature, the yield of organic phase and the properties of bio-oil from crude fat and all components have same varying trend, and their best properties are obtained at 600 ℃. The content of oxygenated compounds in the crude fat including alcohols, acids and esters decreases and that of aliphatic hydrocarbon severely increases after being pyrolyzed. Compared with the pyrolysis of all components, the deoxidizing ratio and the content of carbon and hydrogen elements in crude fat after being pyrolyzed are higher, therefore the performance could be further improved with the increase of fat in the Nannochloropsis sp.. According to the kinetic data, the pyrolysis of crude fat and all components follows the second order reaction mechanism. The pyrolysis activation energy and pre-exponential factor are 64.34 kJ/mol and 2.94×105 min-1 for crude fat, and 48.13 kJ/mol and 2.96×103 min-1 for all components.
Abstract: The hydrothermal catalytic liquefaction of corn stalk (CS) in a 500 mL batch reactor was conducted. The influence of reaction temperature and catalyst quantity as well as reaction time on the products distribution was investigated. The main components and functional groups of bio-oil with and without catalysts were characterized by gas chromatography/mass spectrometry (GC-MS) and Fourier transform infrared spectrometry (FT-IR). The result shows that the optimal conditions of liquefaction are 15 g CS with 6.67% FeHZSM-5 at 340 ℃ for 30 min, at which the bio-oil yield reaches a maximum of 28.03% with the highest CS conversion of 81.73%. The main components of bio-oil are phenols and esters, and the HHV of the bio-oil reaches to 30.08 MJ/kg.
Abstract: With hydrothermally synthesized MCM-41 and Zr-MCM-41 as the supports, Ni2P/Zr-MCM-41 catalysts were prepared by co-impregnation with Ni (NO3)2 and (NH4)2HPO4 solution, calcination, reduction with H2 and subsequent passivation. The Ni2P/Zr-MCM-41 catalysts were characterized by XRD, Py-IR, TEM, XPS, N2 physisorption and CO chemisorption; their catalytic performance in the hydrodeoxygenation (HDO) of Jatropha curcas oil to produce the second-generation biodiesel was investigated in an autoclave. The results indicated that Ni2P can be well dispersed on Zr-MCM-41 with a loading of 20% by reduction at 650 ℃ from the phosphate precursors. The Ni2P/Zr-MCM-41 catalyst exhibit excellent performance in the HDO of Jatropha curcas oil. Over the Ni2P/Zr-MCM-41 catalyst with a Ni2P loading of 20%, the HDO conversion achieves 93.90% and the fraction of linear paraffins in the product oil reaches 85.36%, in which diesel fraction (C15~20) may exceed 61.90%; the components of oil generated through HDO are similar to those of fossil diesel.
Abstract: Steam reforming of methanol was carried out on the copper-silica aerogel catalyst. The effects of reaction temperature, feed rate, water to methanol molar ratio and carrier gas flow rate on the H2 production rate and CO selectivity were investigated. Methanol conversion was increased considerably in the range of about 240-300, after which it increased at a slightly lower rate. The used feed flow rate, steam to methanol molar ratio and carrier gas flow were 1.2-9.0 mL/h, 1.2-5.0 and 20-80 mL/min, respectively. Reducing the feed flow rate increased the H2 production rate. It was found that an increase in the water to methanol ratio and decreasing the carrier gas flow rate slightly increases the H2 production rate. Increasing the water to methanol ratio causes the lowest temperature in which CO formation was observed to rise, so that for the ratio of 5.0 no CO formation was detected in temperatures lower than 375 ℃. In all conditions, by approaching the complete conversion, increasing the main product concentration, increasing the temperature and contact time, and decreasing the steam to methanol ratio, the CO selectivity was increased. These results suggested that CO was formed as a secondary product through reverse water-gas shift reaction and did not participate in the methanol steam reforming reaction mechanism.
Abstract: The reaction mechanism of hydroisomerization of n-alkanes, from n-decane to n-tetrodecane, over Pt/SAPO-11 catalyst was studied. Results indicated that the n-alkanes with different carbon atom numbers exhibited higher isomerization selectivity at lower temperatures. The isomerization selectivity of n-alkanes can reach 90% by controlling temperature to keep the conversion rate lower than 85%. The conversion rate of n-alkanes was increased and the selectivity of isomerization was decreased with the increase of carbon atom number and temperature due to the occurrence of cracking reaction. Bifunctional catalyst has a good product shape selective effects. The isomerization products are mainly composed of unilateral chain isomers which have the methyl at the end and the center of the carbon chain. At low conversion rate, the cracking reaction of the long-chain n-alkanes over the Pt/SAPO-11 catalyst was mainly catalytic hydrocracking, the carbon number distribution of the cracking products was uniform. However, at high conversion rate, the reaction was mainly acid catalytic cracking, the carbon number distribution of cracking products was obvious asymmetric distribution.
Abstract: The mesoporous molecular sieves MCM-41 and Co-MCM-41 containing different cobalt contents were prepared by hydrothermal synthesis method with cobalt nitrate as cobalt source and characterized using X-ray diffraction (XRD), Fourier transform infrared spectrum (FT-IR) and nitrogen adsorption. The characterization results indicate that the well-ordered mesostructure was obtained even when the Co/Si mol ratio was 0.1 and Co has been introduced into the framework of MCM-41. Adsorption removal of basic nitrogen compounds from 0# diesel oil was studied by static stirring method using MCM-41 and Co-MCM-41. One gram of Co-MCM-41(2) could adsorb 5.324 mg nitrogen from diesel oil while MCM-41 could adsorb 2.532 mg, indicating that the adsorptive denitrification of Co-MCM-41(2) has been enhanced pronouncedly. But the adsorptive denitrification capacity of Co-MCM-41(2) decreased when the Co/Si exceeded 0.06, which could be ascribed to the addition of exceeded Co into the frameworks of MCM-41. The Co was well dispersed in the channel of Co-MCM-41 as Co3O4 and blocked the adsorption active sites which hindered the adsorption between the nitrogen compounds and active sites and depressed the adsorptive denitrification capacity. The results of adsorptive denitrification from diesel oil using dynamic adsorption method showed that for a breakthrough point of 10 μg/g, the breakthrough volume and breakthrough capacity of Co-MCM-41(2) at ambient conditions are 35 mL/g-adsorbent and 4.2 mg-nitrogen/g adsorbent, respectively. For MCM-41, both of the two data were almost zero, indicating that MCM-41 almost lost all the adsorptive denitrification capacity due to the shorter contact time and implying that Co-MCM-41(2) had better selectivity on basic nitrogen compounds in 0# diesel oil.
Abstract: Two amino acid ionic liquids (AAILs), viz., tetramethyl ammonium glycinate ([N1111][Gly]) and tetramethyl ammonium lysine ([N1111][Lys]) were supported on porous silica gel through impregnation evaporation method and used as the adsorbents for carbon dioxide. They were characterized by elemental analysis (EA), thermogravimetric analysis (TGA), nitrogen physisorption and Fourier transform infrared (FT-IR) spectroscopy; the effects of AAIL type, loading and temperature on their adsorption capacity towards carbon dioxide were investigated. The results illustrate that AAILs are successfully immobilized into the porous silica gel and the supported sorbents exhibit excellent performance towards carbon dioxide, i.e. fast adsorption rate and high capacity. At 303.15-323.15 K, the adsorption capacity reduces with the increase of temperature, whereas there is a optimal loading of ionic liquids to get highest adsorption capacity towards carbon dioxide. Under 30 ℃ and 0.1 MPa, the [N1111][Gly]/SG adsorbent with a [N1111][Gly] loading of 22.4% exhibits the highest CO2 capture capacity, i.e. 41 mg/g, equivalent to 0.62 mol CO2 per mol AAILs; moreover, 90% of the equilibrium adsorption amount can be achieved in 20 min. Furthermore, no obvious decrease in the adsorption capacity is observed after recycling for six times.
Abstract: The supersaturated water vapor environment for condensational growth of fine particles (PM2.5) and SO3 acid mist was achieved by adding water vapor or humid air into the limestone-gypsum desulfurized flue gas. The influences of the addition amount of water vapor and humid air as well as the desulfurized flue gas temperature were analyzed based on the property analysis of PM2.5 and SO3 acid mist. The results show that except for coal-fired ash, the desulfurized flue gas also includes CaSO4, CaSO3 and unreacted CaCO3 in PM2.5. The removal efficiency of SO3 acid mist is 35%-55% merely by wet flue gas desulfurization (WFGD) system because SO3 acid mist is mostly submicron particles. PM2.5 and SO3 acid mist can be removed effectively by adding either water vapor or humid air, and the emission concentration decreases with increasing the amount of water vapor or humid air. Moreover, it is found that it is better to add water vapor to establish the supersaturated water vapor environment for lower temperature desulfurized flue gas (≤50-55 ℃), while it is more appropriate to add humid air for higher temperature desulfurized flue gas (≥55-60℃).
Abstract: Municipal solid waste pyrolysis, gasification and incineration experiments were conducted in a fluidized bed reactor to investigate the effect of redox atmosphere and temperature on the fate of heavy metals (Cd, Pb, Zn and Cu). The results show that higher temperature and reductive atmosphere are effective for the evaporation of Cd, Pb and Zn; while the oxidative condition favors the migration of Cu. Thermodynamic equilibrium calculation confirms that the metal species differ a lot under redox conditions. Metals are mainly existed as elemental forms or sulfide under reductive atmosphere; and their volatility depends on the metal boiling point dominantly. On the contrary, the formation of metal chlorides such as CuCl3 increases the volatilization of Cu in an oxidative atmosphere. Besides, the evaporation of Cd, Pb and Zn is postponed under oxidative condition due to the metal-matrix reactions. The distribution of heavy metals in different fractions was further examined. The majority of the vaporized metals are condensed and enriched in the fly ash upon cooling. Entrainment also poses a significant influence on the migration of metals, which is determined by the characteristics of high gas velocity used in fluidized bed.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
