Abstract: To investigate the effects of cations on equilibrium re-adsorption water content of lignite, the acid-washed Shengli lignite was exchanged with different concentrations of K2SO4, Na2SO4, MgSO4, Ca(CH2COOH)2 solution, respectively. Ion-exchange process was characterized by the changes in wavenumber of carboxyl group and the ash contents. The equilibrium adsorption water contents of all samples were determined in a range of relative humidities. It is shown that the extent of ion-exchanged exchange in Shengli coal is in order of Ca2+>Na+>K+>Mg2+. The relative effectiveness of cations in increasing the equilibrium adsorption water content is in order of Mg2+>Ca2+>Na+≈K+. At high relative humidity, the factor that control equilibrium adsorption water content is free water molecules interactions. However, at middle relative humidity capillary force between metal cation-carboxyl group complex and capillary is more important. At low relative humidity water interactions with sorption sites which are cation-carboxyl group complex become more important.
Abstract: In order to find an efficient and feasible technological route to dispose and utilize deoiled asphalt (DOA, a byproduct of solvent deasphalting process), the co-pyrolysis/gasification of DOA with different rank of coal was investigated. A series of isothermal co-pyrolysis experiments were conducted in a fixed bed reactor to observe the characteristics of the char yields and the pattern of the blends. Then a set of non-isothermal experiments were performed by thermogravimetric system to evaluate the gasification characteristics of the chars of coal, DOA and the blends. It is observed that the co-pyrolysis char formed as blocks, while the char yields show that the co-pyrolysis process has no interaction between the two resources. The gasification reactivity of the DOA char is lower than that of lignite and bituminous coal char, and is a bit higher than that of anthracite char. The gasification reactivity of the blended char of DOA with lignite/bituminous coal is found higher than that of the calculated, which clearly demonstrating that the synergetic effect existed during the gasification process, and that is mainly caused by the minerals such as Ca, Fe contained in coal char.
Abstract: The reactivity between the CaSO4 oxygen carrier with CaO additive and coal under steam atmosphere was studied in a fluidized bed reactor. The experimental results show that the addition of CaO can improve the performance of both coal gasification and CaSO4 reduction, and increase the reaction rate of coal gasification and CaSO4 reduction and the CO2 generating rate. However, the catalysis of CaO drops as the reaction temperature rises. And the optimum reaction temperature is 900 ℃, at which the releases of gaseous sulfides are remarkably decreased by 63.19% and 27.37% for SO2 and H2S, respectively, as the molar ratio of CaO to CaSO4 is 1.18. Meanwhile, the amount of CO2 absorbed by CaO can be controlled to less than 2%.
Abstract: The pressurized O2/CO2 combustion is a potential technique, which makes CO2 separation and recovery more efficient. However, it has a notably different mechanism from the air combustion and the O2/CO2 combustion under atmospheric pressure. The combustion characteristics of an American bituminous coal and a Huaibei anthracite coal under O2/CO2 atmosphere were studied employing the thermo-gravimetric analyzer at various pressures (p=0.1~1.5 MPa). The influences of pressure, oxygen concentration, atmosphere and particle size on the coal combustion characteristics were inspected, and the ignition temperature was obtained. Also, the combustion kinetic parameters were calculated. The results indicate that as the total pressure or oxygen concentration increases, DTG curves move to the low temperature zone and the overall combustion rate of coal samples is accelerated under pressurized O2/CO2 atmosphere. The ignition characteristics of pulverized coal could be improved through the pressure enhancement, the increase of oxygen concentration and the reduction of particle size. The pulverized coal combustion under atmospheric pressure is basically a first order reaction. For pressurized oxy-fuel combustion, the reaction order is 0.5 under the low temperature zone, while the reaction order becomes 1.5 under the high temperature zone.
Abstract: Cellulose pyrolysis was studied in a fixed bed reactor at 500~900 ℃; the tar and gaseous products were analyzed by GC-MS and gas chromatograph, respectively. The results showed that the yield of gaseous products increases and that of tar and char decreases with the increase of pyrolysis temperature; the yield of CO, CH4 and H2 is increased significantly, while the yield of CO2 is almost not altered. Tar is generated by the secondary reactions, while the non-condensable gases are generated by both the primary and secondary pyrolysis products. The mechanism of tar decomposition was considered through calculation with Gaussian 09, which suggests that cellulose is cleaved into cellulose monomer at the beginning of pyrolysis process. The hydroxy functional groups are removed from cellulose monomer preferentially, and then the intermediates are reformed into tar. With the increase of temperature, ethers, alcohols, acids and other compounds in tar are decomposed into free radicals; the amounts of alkenes, alkynes and non-condensable gases formed are then increased because of the reformation of free radicals at high temperature.
Abstract: Pine loaded K2CO3 were pyrolysed by tubular furnace. The experiment of pyrolysis vapor of pine passed through sand mixed with K2CO3 or char added K2CO3 were also performed to simulated the effects of potassium on vapor. The results indicated that K could catalyze pyrolysis process, increase the char yields and decrease CO yields markedly. K could increase the gas yield in low temperature while decrease it in higher temperature. The pyrolysis vapor could decompose when pass through K, which lead to lower liquid yield and higher CO, CO2, H2 yield. Char of pine also could catalyze tar cracking, increase H2, CO2 and decrease CO, CH4, C2 yields in gas. Char added K was favor to the cracking of tar and the reaction between gas and char. Effects of potassium on biomass pyrolysis characteristics was achieved by catalyzing the primary pyrolysis and the reaction of the pyrolysis vapor.
Abstract: Three materials including raw and water-washed ice straw, and microcrystalline cellulose with 5%KCl loaded were pyrolysed in the fixed bed reactor to investigate the transfer of potassium in four forms. The results indicate that the release of potassium changes little with pyrolysis temperature below 700 ℃, and the release of potassium dramatically increases with pyrolysis temperature above 700 ℃. During the rice straw pyrolysis, the transfer of four forms of potassium takes place, in which the water soluble and the potassium in residue decrease. It is confirmed that the potassium combined with carbon can be partly changed to water soluble, and the water soluble and organically bound potassium can exchange each other during pyrolysis.
Abstract: The liquefaction of ligno-cellulosic biomass materials of bamboo, poplar, pine and eucalyptus woods was investigated in methanol under high pressure with H2SO4 as catalyst. The results indicated that the biomass materials are converted into bio-gas, solid residue and bio-oil after reaction at 200 ℃ for 30 min. The bio-oil can be further separated into a variety of high value-added products such as alkyl polyglycosides, levulinate acid esters, and polyphenols. Alkyl polyglycosides is the main component of the liquefied products and accounts for 83.38% by weight; besides, phenolic products are mainly composed of 4-ethyl-2-methoxyphenol, eugenol and 3, 4-dimethoxyphenol, which account for about 65.79% by weight. Considering the molecular structure of lingo-cellulosic materials, it was proposed that cellulose and hemicellulose are transformed to alkyl glucoside, levulinate esters, etc. with methanol catalyzed by sulfuric acid under high pressure. Due to electron donating effects of phenolic hydroxyl and methoxy groups, guaiacol, phenol and a series of phenolic compounds are formed through the cleavage of C-C bond of guaiacyl units in lignin.
Abstract: Two series of ten transition metal complexes were prepared as the catalysts for the catalytic aquathermolysis of heavy oil at relatively low temperature. In this reaction system, the dosage of water can affect the aquathermolysis efficiency, and the proper mass fraction of water/oil is 0.3. Some complexes can catalyze the aquathermolysis effectively at 180 ℃, in which N5 catalyst is the most effective one to drop the pour point with 11.4 ℃, while N2 and N5 catalysts are the most effective ones to reduce the viscosity by more than 70%. The proper dosage of N5 catalyst in this reaction system is 0.5%. TG and GC analysis show that the light components increase remarkably after the aquathermolysis.
Abstract: A series of Co/SBA-16 catalysts were prepared by the incipient wetness impregnation method and characterized with N2 physisorption，X-ray diffraction，H2-temperature programmed reduction，hydrogen chemisorption and transmission electron microscopy techniques. It was found that the Co0 dispersion decreased with increasing cobalt loading，being consistent with the increase of Co3O4 crystallite sizes and the decrease of BET surface area. The Co/SBA-16 catalysts show high CO conversion，low C1 selectivity，high C5+ hydrocarbon selectivity，and especially high selectivity towards diesel fraction.
Abstract: SBA-15 supports modified by different hydrophobic reagents (methyltriethoxysilane, dimethyldiethoxysilane and chlorotrimethylsilane) were prepared before the impregnation of cobalt precursor. The effects of hydrophobic modification on the crystallite structure and the reduction behaviors were studied by BET, FT-IR, 29Si CP MAS NMR, XRD, and H2-TPR. Fischer-Tropsch (F-T) synthesis performances were evaluated in a fixed-bed reactor at 2.0 MPa, 200~250 ℃, H2/CO (volume ratio)=2, and GHSV=1 000 h-1. The result indicated that hydrophobic modification led to the increase in reduction degree of the supported cobalt, resulting in the increase of CO conversion of cobalt catalysts for F-T synthesis. Moreover, due to the increase of Co3O4 crystallite size and the decrease of un-reducible cobalt compound after hydrophobic modification, CH4 selectivity decreased and C5+ selectivity increased.
Abstract: Carbon dioxide reforming of methane to synthesis gas was investigated with a series of Ni catalysts supported on Hydroxyapatite (HAp) prepared by chemical precipitation at low temperature. The structure and properties of the catalysts were characterized using BET, H2-TPR, XRD, SEM, FT-IR , TEM and TG-DTA techniques. The 13% NiO/HAp showed the highest activity for catalytic carbon dioxide reforming of methane to synthesis gas. Under the condition of an atmospheric pressure at 850 ℃ and a gas hour space velocity (GHSV) of 3.6 ×104 mL/(h·gcat), the conversion of CH4 and CO2 over 13% Ni/HAp catalyst remained almost constant, at about 72% and 83%, for 10 h, respectively, which was ascribed to strong metal-support interaction. Most of the carbonaceous deposits on the catalyst surface were in whisker form, which did not cover the active sites and then had limited influence on the catalyst activity and stability.
Abstract: Chitosan salicylaldehyde Schiff-base manganese complex (Mn-CS-sal) was synthesized by a simple chemical method and then supported on graphite carbon; the graphite-supported Mn-CS-sal (Mn-CS-sal/C) was heat-treated at different temperatures (t) to obtain the Mn-N-C catalysts (Mn-N-C-t, t=200, 400, 600, 800, 1 000 ℃). The electrocatalytic activity of Mn-N-C catalysts in the oxygen reduction reaction (ORR) was investigated and their structure and composition were characterized by Fourier Transform Infrared (FT-IR) spectrum, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results indicated that all the Mn-N-C catalysts are highly active in ORR, whereas the Mn-N-C-600 catalyst heat-treated at 600 ℃ exhibits the highest ORR activity. The excellent ORR activity of the Mn-N-C catalysts in alkaline media should be attributed to their Mn-N-C configuration. Two important kinetic parameters, i.e. the overall ORR electron transfer number (n) and electron transfer coefficiency (αnα), were determined by the cyclic voltammetry method. The Mn-N-C-600 catalyst shows an overall electron transfer number of 3.63 for ORR, suggesting that the catalytic ORR is via a mixture of 2- and 4-electron transfer pathways, but dominated by the 4-electron transfer process. Based on these observations, a possible mechanism for ORR over the surface of Mn-N-C modified electrode is proposed.
Abstract: Two kinds of graphene GN-1 and GN-2 with significantly increased specific surface area were obtained from nano graphite by different methods. The morphology and pore size distribution of GN-1 and GN-2 also have great differences. Using these two kinds of graphene as supports, Pd catalysts were prepared and designed as Pd/GN-1 and Pd/GN-2. The electrochemical specific surface area of Pd/GN-1 and Pd/GN-2 catalysts are 34.66 and 71.25 m2/g. The catalytic activities of Pd/GN-1 and Pd/GN-2 during the formic acid electrooxidation reaction are greatly improved compared with the Pd catalyst supported by nano graphite. The peak current densities of formic acid oxidation on Pd/GN-1 and Pd/GN-2 are 66.0 and 95.8 mA/cm2. The Pd/GN-1 and Pd/GN-2 catalysts also have good stability for formic acid electrooxidation.
Abstract: A microbial fuel cell (MFC) was built using glucose as simulated domestic wastewater, using carbon felt as anode and activated anaerobic sludge as inoculum, which came from a sewage treatment plant. The sewage was treated and electricity was generated synchronously. The effect of substrate concentration and operating temperature on electrode process kinetics was examined. The relationship among electrochemical activity of microbes, charge transfer resistance, anode potential, and capacity of producing electricity was explored. The main conclusions about sewage-fuel MFC are summarized as follows: The relationship between the peak power density and substrate concentration followed Monod enzyme kinetics equation: P=Pmaxc/(ks+c), with a maximum power density (Pmax) of 320.2 mW/m2 and half-saturation concentration (ks) of 138.5 mg/L. When the initial glucose concentration is less than 2 000 mg/L, the reaction follows the first order kinetics equation: -dcA/dt=kcA, k=0.262 h-1. Increasing the temperature from 20 to 35 ℃, the charge transfer resistance decreases from 361.2 to 36.2 Ω, the anode electrode potential also decreases, while peak power density increases from 80.6 to 183.3 mW/m2. At 45 ℃, the electrochemical activity of microbes declines, and the peak power density decreases to 36.8 mW/m2. After operating steadily for 6 h, coulombic efficiency and COD removal efficiency reach a maximum of 44.6% and 49.2%, respectively, at 35 ℃ with the substrate concentration of 1 500 mg/L.
Abstract: N-doped activated carbons (ACM) was obtained by impregnated activated carbon (AC) with melamine (M). The relationship between the impregnated time and calcination temperature on the nitrogen content and NH3-SCR activity was investigated. Results showed that SCR activity of ACM was higher than original AC. For ACM-5-900 was about 51.67% at 80 ℃ while AC was about 21.92%. Characterizations of BET, element analysis and XPS were employed to study the structural properties, nitrogen contents and distribution of nitrogen-containing groups of ACM. Results indicated that NO conversion of ACM was influenced by the form of nitrogen-containing functional groups rather than the nitrogen content. The NO+O2-TPD revealed that nitrogen-containing surface groups of ACM facilitated the adsorption and oxidation of NO, leading to the higher NO conversion. However, SO2 played an inhibit role on NO conversion of ACM.
Abstract: The bimetal Ni-Mo catalysts supported on γ-Al2O3 were prepared and used for the selective hydrogenation of FCC gasoline for sulfur transfer. The reaction mechanism of sulfur transfer on Ni-Mo/Al2O3 catalyst was studied and the influence of reaction conditions on sulfur transfer was investigated. The results showed that the reaction of thiol and olefin happened on the active sites of hydrogenation on catalyst surface. Hydrodesulfurization of small molecule thiol firstly produced adsorbed hydrogen sulfide, then the adsorbed hydrogen sulfide reacted with adsorbed olefin and formed macromolecular thiol or thioether; Besides, small molecule thiol can also directly reacted with olefins to produce thioether. The activity of sulfur transfer reaction of Ni-Mo/Al2O3 catalyst was improved through the increase of reaction temperature, pressure, and H2/oil ratio or the decrease of LHSV. The conversion of light sulfur compounds was obviously improved, and mono-olefins selectivity was maintained at around 98%.
Abstract: Poly(oxymethylene) dimethyl ethers (PODE n, n>1) were synthesized by the condensation of trioxymethylene (TR) and methanol (MeOH) over the functionalized ionic liquids like [Hnmp]HSO4, [Hnmp]H2PO4, [Hnmp]PTSA and [PyN(CH2)3SO3H]HSO4; the effects of the catalyst amount, raw materials ratio, temperature, pressure and time on the reaction behaviors were investigated. The results showed that the catalytic activity of ionic liquid is related to its acidity. [PyN(CH2)3SO3H]HSO4 exhibits the highest catalytic activity; under the optimum reaction conditions, i.e. [PyN(CH2)3SO3H]HSO4 amount of 2.0%, molar ratio of MeOH to TR of 2.0, 110 ℃, 2.0MPa and reaction time of 6h, the conversion of TR and selectivity to PODE3~8 reach 97.69% and 32.54%, respectively. Moreover, the ionic liquid [PyN(CH2)3SO3H]HSO4 can be spontaneously separated from product phase after the reaction.
Abstract: Hydrogen production was studied in the Cu-P oxidation-reduction system with water. The influence of Cu /P ratio, reaction temperature, acidity and additional Cu on hydrogen yield was investigated. The green process of Cu-P system was realized by the design of the copper recycling and the phosphorus transformation and utilization. The results showed the hydrogen yield from the hydrogen atom in the reaction was mainly dependent on the Cu/P ratio and the reaction temperature, with the optimal yield of 18.6 mL under the conditions of 95 ℃ and 0.05 mol ratio of Cu to P with 0.20 g CuSO4·5H2O. H2O2 oxidation of elemental Cu in Cu-P system was also achieved for 10 times recycling under acidic condition. FT-IR and XRD results revealed that H2PO3-from the hydrogen production process could be converted into the new antirust CaHPO3·H2O with Ca(OH)2.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
