Abstract: In order to reveal the pyrolysis and coking characteristics of different components in coal, the macerals in Huangling coal were enriched by centrifugation, and the pyrolysis characteristics of macerals were studied. The transformation characteristics of macerals during pyrolysis were observed in-situ by heating stage microscope. The purities of vitrinite and inertinite are more than 90% and 80%, respectively, while the purity of liptinite is nearly 70%. The initial pyrolysis temperature of liptinite is about 385 ℃, and those of the other macerals are all about 410 ℃. The maximum pyrolysis temperatures are between 470−480 ℃ for all macerals studied. The maximum weight loss rate and the total weight loss rate decrease in the order of liptinite, vitrinite, semi-vitrinite and inertinite. The softening temperature of the liptinite (including sapropelic groundmass) is 350−370 ℃, while that of vitrinite is about 410−420 ℃ as shown by the in-situ pyrolysis in a heating stage microscope. The pyrolysis process of vitrinite goes through the stages of edge shrinking, pore formation, surface softening, the formation of liquid phase, and solidification. Only slight morphological changes are observed in semi-vitrinite, while no changes are observed in inertinite. The active components in Huangling coal are vitrinite and liptinite, and the liptinite can promote the softening and melting characteristics of the adjacent vitrinite.
Abstract: During the coal pyrolysis with the coal ash as heat carrier, the interactions of coal ash and volatile matters could occur in the secondary reactions, which would affect the final sulfur-containing product yields of volatile matter. The objective of this paper was to reveal the effects of coal ash on the sulfur transformation during the secondary reactions. The results showed that the presence of XLT ash during secondary reactions inhibited H2S and COS release at low temperatures due to the sulfur fixation of Fe2O3 existed in the ash. However, it enhanced H2S and COS release at high temperatures, which was mainly caused by the formation of sulfur-containing gases through the reactions between CaSO4 and reducing gas (i.e. H2, CO, and CH4). The influences of Fe2O3 and CaSO4 were also investigated to reveal the mechanism of the influence of coal ash, and it was found that H2S and COS yields were reduced with the addition of Fe2O3, but those two gases were slightly increased by the presence of CaSO4 at 800 ℃, indicating that Fe2O3 and CaSO4 played important roles in the interactions between the coal ash and sulfur-containing gases.
Abstract: In this work, the separation of phenol from oil mixtures was proposed by using mildronate (THP), Girard's Reagent T, and Girard's Reagent P. The results showed that the mentioned separation agents could form deep eutectic solvent (DES) with phenol and then separate phenol. The highest separation efficiency of phenol was 96.5% by THP, and the residual phenol content in oil was as low as 1.3 g/L; the separation could be finished in 10 min; the initial phenol content had no effect on the minimum residual phenol content (about 8.8 g/L) in oil after separation. An n-hexane washing method was used to remove the neutral oil entrained in DES. The results showed that the mass ratio of neutral oil to phenol in DES was reduced to 0.04, indicated that the purity of phenol product was greatly improved. THP was renewable and its properties remained unchanged after be reused for 5 times. Finally, FT-IR spectra showed that hydrogen bonds were formed between THP and phenol.
Abstract: The effects of pretreatment methods (DR, R, ROR) on the microstructure of Co/SiO2 catalysts and the activity for Fischer-Tropsch synthesis (FTS) were investigated. The pretreated catalysts were characterized by TEM, HRTEM, XRD, XPS, H2-TPD, TG and TPR. The results showed that after the pretreatments, specific morphological of the Co species changed, forming new Co active surface species. The Co particles redispersed and the Co species was facile to be re-reduced. The Co/SiO2 catalysts pretreated by different method showed different catalytic performance. The catalyst treated by the reduction-passivation had higher activity and C5+ selectivity for FTS.
Abstract: Conductive carbon film has a wide range of application prospects, especially in the fields of electric heating devices, energy storage devices, and solar cells. Coal tar is an ideal precursor for preparing carbon film. In order to improve the performance of coal tar-based carbon film, it is necessary to study the influence of tar composition on the structure and performance of carbon film. In this paper, a carbon film is prepared using aromatic compounds, heteroatom compounds and tar as carbon sources. It is found that the carrier concentration of aromatic hydrocarbon-based carbon films is higher than 1022 cm−3, but the mobility of the carrier is lower than 1 cm2/Vs. The resistivity and sheet resistance of the aromatic hydrocarbon-based carbon film are lower than that of the coal tar-based carbon film. Naphthalene-based carbon film has the best electrical and thermal properties. The maximum heating temperature of naphthalene-based carbon film at 30 V exceeds 300 °C. The thickness of the carbon film has a decisive influence on the sheet resistance of the carbon film. The performance of the heteroatom compound-based carbon film is significantly lower than that of aromatic compound-based film.
Abstract: Accompanying with the rapid consumption of fossil fuel resources, a huge amount of CO2 has being released into the atmosphere, which brings serious environmental concerns. However, CO2 can also be considered as a clean and non-toxic carbon resource; the utilization of CO2 by converting it into various hydrocarbons can not only alleviate the greenhouse effect, but also provide a new sustainable route to produce clean fuel and chemical products. In this paper, we attempt to make a review on the recent research progresses in the hydrogenation of CO2 to certain hydrocarbons (including methane, olefins and aromatics) in recent years; in particular, the advance in the development of efficient catalysts for the hydrogenation of CO2 to methane, light olefins and aromatics as well as in the exploration of catalytic reaction mechanisms were retrospectively summarized. Lastly, we would like to have an outlook on the possible trends in the utilization of CO2 as a carbon resource through hydrogenation.
Abstract: Alkylbenzenes are important bulky chemicals. The production of alkylbenzenes through benzene and syngas alkylation technology of coal chemical industry can reduce the domestic dependence on petroleum. In this study, mechanical mixture of ZnAlOx and ZSM-5 were used to catalyze the alkylation reaction of benzene and syngas. The results showed that the best performance catalyst was obtained with the 1∶1 mass ratio of the two components and the 2∶1 molar ratio of zinc to aluminum. It was suggested that the main reaction intermediates of methanol and dimethyl are produced on the O vacancy of ZnO and L acidic center of Al2O3 in ZnAlOx. And the alkylated benzenes are formed by the reaction of benzene with the intermediates over ZSM-5. Due to the high temperature property of ZnAlOx for methanol synthesis which can accommodate to the reaction of ZSM-5 for benzene alkylation, the high catalytic activity and selectivity was obtained.
Abstract: Previous works demonstrated that the Fe-Ag/Al2O3 catalyst could efficiently reduce NO into N2 by propene with a good resistance towards H2O and SO2. In this work, the effect of preparation method on the performance of Fe-Ag/Al2O3 catalyst in the selective catalytic reduction (SCR) of NO with propene was investigated. Three typical methods, viz., physical grinding (PG), direct impregnation (DI) and sol-gel-impregnation (SGI), were comparatively used to load the active components on the supports. The results indicate that all the catalysts prepared by these three methods display good tolerance towards water vapor and SO2. However, they are rather different in the denitration efficiency; the maximum NO removal efficiency of the catalysts prepared by three methods follows the order of SGI (100%) > PG (62%) > DI (58%). Various characterization results reveal that the catalytic performance of Fe-Ag/Al2O3/CM was mainly related to the porous surface and Fe-Ag interaction. By using the SGI approach, the primary support of cordierite and the secondary support of Al2O3 work together to achieve a large surface area and an intense interaction between Fe and Ag on the resultant DP-Fe/Ag/Al2O3/CM catalyst, forming the bimetal AgFeO2 oxide and displaying the best reducibility. In terms of the PG method, the prepared GR-Fe/Ag/Al2O3 catalyst is powdery and shows the largest surface area; however, without cordierite serving as the monolithic support, Ag2O and Fe3O4 exist as separate oxides together with a hint of elemental Ag. As a result, the GR-Fe/Ag/Al2O3 catalyst shows poor reducibility due to the lack of porous surface to facilitate the Fe-Ag interaction. In contrast, the DP-Fe/Ag/CM catalyst prepared using the DI method shows rather poor dispersion of Fe and Ag due to the absence of the secondary support of Al2O3; in fact, individual Ag2O and Fe3O4 agglomerate on the catalyst surface and no AgFeO2 species is detected. Therefore, the DP-Fe/Ag/CM catalyst, with the surface area of only 1/4 of that for Fe-Ag/Al2O3/CM-SGI, exhibits the poorest activity in the SCR of NO by propene.
Abstract: Tanning sludge, chrome tanned buffing dust and chrome shavings were selected as experimental materials. The non-isothermal distributed activation energy model (DAEM) was used to study the pyrolysis kinetic parameters. Effects of particle size and temperature on distribution of co-pyrolysis products of various tanning wastes were investigated in a fixed-bed pyrolysis reactor, which provided a new approach for comprehensive thermal treatment of various tannery wastes. The results show that the total activation energy required for the co-pyrolysis decreases and then increases in the range of conversion rate of 0.1 to 0.8. The tar yield decreases with raising particle size, while the yields of gas and char increase. With increasing pyrolysis temperature, the tar yield increases rapidly to a peak value of 17% at 600℃, and then decreases, correspondingly the char yield decreases while the gas yield increases. At 600 ℃ and the particle size of 1.6–2.5 mm, specific surface area of the char is larger, and the light fractions in tar is higher. Thus, co-pyrolysis is conducive to clean treatment of the tannery wastes.
Abstract: Using cheap coal pitch as raw material and adding pore-forming agent, the carbon material with three-dimensional skeleton structure was obtained by mixing process, air oxidation stabilization process and carbonization process successively, and then the porous carbon material with high specific surface area was obtained by water vapor activation. Thermogravimetric and elemental analysis were used to study the thermal reaction characteristics and structural changes of the samples after oxidation stabilization and carbonization. The surface morphology, pore structure and electrochemical properties of the activated samples were characterized by scanning electron microscope, BET method and electrochemical workstation. After water vapor activation, BET of porous carbon can reach 1638 m2/g. The water-based double layer capacitors prepared with this porous carbon as the electrode material of supercapacitors have good cyclic performance, and the specific capacitance can reach 252 F/g at 1 A/g current density. After 10000 cycles, the specific capacity can still maintain 97.3%. Therefore, the porous carbon materials prepared by this method have low cost and good chemical stability, and can be used as an ideal electrode material for supercapacitors.
Abstract: In this study, the structure and combustion performance of pyrolysis chars from Daliuta raw coal, vitrinite-rich sample, inertinite-rich sample and demineralized coal sample were studied by Raman spectroscopy. The results showed that under the same pyrolysis conditions, compared with the pyrolysis char from Daliuta raw coal sample, the pyrolysis char from the demineralized coal sample has more large aromatic ring systems (≥ 6 rings), higher ignition temperature and much low combustion performance. The combustion performance of pyrolysis char from inertinite-rich sample is lower than that from vitrinite-rich sample, and the burnout capacity of pyrolysis char from inertinite-rich sample is far lower than that from vitrinite-rich sample. The ignition temperature (ti), the combustion reactivity index (tindex) and the wavenumber of D band (WD) in the Raman spectrum of Daliuta coal char has a good correlation; the correlation coefficients R2 obtained by the quadratic curve fitting are 0.9159 and 0.7133, respectively. There is no obvious correlation between burn-out temperature and WD of Daliuta coal char, indicating that the carbon structure of Daliuta coal char has a significant impact on the ignition temperature and combustion reactivity index of the char, but is no regular effect on the burn-out ability of the char.
Abstract: The size distribution of aromatic nuclei in coal influences the composition of tar and char during pyrolysis. Pyrolytic experiments of Naomaohu (NMH) coal from Xinjiang in China were carried out in a fixed-bed reactor at different temperatures to study the size distribution of aromatic nuclei during coal pyrolysis. With the increase of pyrolysis temperature, the aromaticity of char, the graphitization degree, and the order degree of aromatic layers increase. The tar is mainly composed of aromatic clusters with 1−2 rings and contains a small amount of aromatic clusters with 3 or more rings. The tar yield increases first and then decreases with increasing temperature (maximum at 550 ℃). However, the changes in the synchronous fluorescence spectra of the tars with increasing temperature are not significant, indicating that the size distribution of aromatic nuclei in tar changes little with no significant condensation polymerization, and also indicating that the number of bridged bonds and the cracking activity distribution of these bridge chains in different size aromatic rings are relatively uniform. With the increase of pyrolysis temperature, the content of 1 × 1 aromatic layers in the pyrolysis products (char and tar) decreases gradually. When the pyrolysis temperature is at between 500 and 600 ℃, the 1 × 1 aromatic layers are mainly transformed into 2 × 2 and 3 × 3 aromatic layers. When the temperature is higher than 650 ℃, the formation of aromatic layers with the size of 4 × 4 and above takes the main part of condensation polymerization.
Abstract: Uranium is a kind of radionuclide and also an important strategic resource. In some areas of China, the content of U in coal is extremely enriched. After high temperature transformation, U in coal can be enriched in solid products, which may cause radioactivity risk. In order to control the release of U and transform U in coal products into resource, it is necessary to investigate the migration law of uranium during thermal utilization of coal. Based on the thermodynamic equilibrium principle, the morphology distribution of uranium was calculated and analyzed in the processes of pyrolysis, gasification and combustion of Ganhe coal, Xiaolongtan coal and Shengli coal. Also the influence of calcium based additives on U migration was analyzed to provide theoretical guidance for subsequent experimental studies. The results show that uranium has different forms in pyrolysis, gasification and combustion processes; UO3(g) is the only gas phase product produced under different working conditions, and higher temperature, lower pressure and stronger oxidation environment can increase the formation amount of UO3(g); volatilization of uranium is significantly week when uranium is fixed to form calcium uranate. Especially, the amount of calcium uranate in Ganhe coal during combustion is increased obviously after the use of calcium based additives and the effect of CaO is the most significant.
Abstract: In this paper, the synthesis of methanol in CO2 hydrogenation on NiO supported In2O3(110) defect surface was studied with the aid of density functional theory (DFT) calculation. Two pathways for methanol synthesis including HCOO route and reverse water gas (RWGS) route were analyzed. The reaction energy and activation energy barrier of each elementary reaction in these two routes were calculated. The results show that the existence of NiO support can enhance the adsorption of CO2 on In2O3 catalyst and promote the generation of methanol via the HCOO route. In HCOO route, the hydrogenation of HCOO to H2COO is the rate-determining step, and it requires to overcome the activation energy barrier of 1.66 eV. The NiO-supported In2O3(110) defect surface exhibits a promoting effect on the hydrogenation of CO2 to methanol via HCOO route, which, hence, improving the efficiency of methanol formation.
Abstract: Using TPAOH as the template, TEOS as the silicon source and TBOT as the titanium source, the as-prepared samples utilizing a dynamic crystallizating kettle possessed regular morphology and the average particle size of 600 nm. By modulating the dosage of TBOT, and then changing the molar ratio of titanium to silicon in the initial synthesis solution, the effect of silicon to titanium ratio on TS-1 molecular sieve was investigated. TS-1 zeolite properties were characterized by means of SEM, TEM, XRD, FT-IR, UV-vis, XPS, N2 adsorption and desorption technology. Finally, using a simulated system of thiophene n-octane dissolved in octane, the catalytic oxidative desulfurization performance of TS-1 zeolite was investigated.
Abstract: TiO2 nanobelts were prepared by hydrothermal synthesis and acid treatment, then calcination at different temperatures. And subsequently Pt nanoparticles were deposited on the TiO2 nanobelts. Pt/TiO2 catalytic properties were investigated in the oxidation of formaldehyde. These catalysts were characterized by various techniques and the characterization results showed that the applied thermal treatment temperature greatly influenced the phase composition and surface structure of TiO2 nanobelts, as well as the number of oxygen vacancies and hydroxyl groups on the surface. The Pt/TiO2 nanobelts thermally treated at 600 °C had more oxygen vacancies, which were conducive to the activation of adsorbed oxygen, formed more Ti-(OH)x-Pt species, and showed higher catalytic activity. At 25 °C and relative humidity of 55%, the conversion of formaldehyde reached 91.6%.
Abstract: MnOx/ZrO2-Cr2O3 catalysts were prepared by cocurrent coprecipitation and impregnation. The structure and surface properties of the catalyst were characterized by X-ray diffraction (XRD), N2 physical adsorption (BET), hydrogen temperature programmed reduction (H2-TPR), and X-ray photoelectron spectroscopy (XPS). These results showed that the addition of Cr led to the transformation of ZrO2 crystal form from m-ZrO2 to t-ZrO2. With the increase of Cr content, the BET of the composite oxide ZrO2-Cr2O3 increased gradually, the average pore size decreased and the pore structure also changed. The impregnation of Mn caused the migration of Cr in the ZrO2-Cr2O3 composite oxide, and promoted the transformation of the ZrO2 crystal form from m-ZrO2 to t-ZrO2, the BET and pore structure of the catalyst changed also. The conversion and selectivity of MnOx/ZrO2-Cr2O3 catalysts containing 4% Mn and 2.5% Cr for methyl benzoate hydrogenation were 93.86% and 86.05%, respectively.
Abstract: The mechanism of adsorption and oxidation of Hg0 by HCl on γ-Fe2O3 surface was investigated by density functional theory (DFT) calculation. The adsorption models of Hg0, HCl, HgCl and HgCl2 on γ-Fe2O3(001) surface were constructed, and the reaction mechanism of catalytic oxidation of Hg0 by HCl on γ-Fe2O3 surface was analyzed. The results illustrate that the Hg0 tends to be chemically adsorbed at Feoct site. HCl can be dissociated and adsorbed on the surface of the catalyst to form adsorbed Cl and hydroxyl groups, and promote the adsorption of Hg0. HgCl can be molecularly chemisorbed upon γ-Fe2O3(001) and act as an intermediate. HgCl2 tends to be adsorbed in parallel on the surface of γ-Fe2O3. HCl oxidizes Hg0 on γ-Fe2O3(001) following the L-H mechanism: chemically adsorbed Hg0 reacts with dissociatively adsorbed HCl. By measuring the energy distribution of the reaction path, the oxidation process of Hg0 on the surface of γ-Fe2O3 was studied. The heterogeneous oxidation of Hg0 by HCl proceeds on a two-step reaction pathway: Hg0(ads)→HgCl(ads)→HgCl2(ads).
Abstract: By changing the simulation conditions of municipal solid waste incineration experiment (nickel catalyst, water), analysing the reaction temperature, incineration exhaust gas flow, concentration of exhaust gas composition, the dioxin concentrations, the toxicity of dioxin equivalent of absorbing liquid, and the change of the absorption liquid organic matter concentration, the effect of different combustion conditions on dioxins from simulated municipal solid waste incineration was explored. The results showed that the addition of nickel catalyst and water could promote the conversion of macromolecule organic matter to small molecule organic matter during the incineration process, and effectively inhibited the precursor synthesis of dioxins, while the suppression ratio of dioxins were 80.7% and the total equivalent toxicity of dioxins were decreased by 98%.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
