Abstract: A novel method was developed to combine electron beam irradiation with electrochemical reduction to increase coal liquefaction degree. Coal samples were irradiated by a stream of high energy electron beam. The samples were treated with tetrahydrofuran to extract the possible products from electron beam irradiation. The products were analyzed to calculate the yield. It was observed that the extract yield increased as the absorbed doses increased, but the increase was more significant when the absorbed dose was 25 kGy in O2 atmosphere. The irradiated samples were further electrochemically reduced in sodium hydroxide electrolyte solution for liquefaction. Corresponding elemental analyses, Fourier Transform Infrared Spectroscopy, linear sweep voltammetry, nuclear magnetic resonance and chronoamperometry were employed to investigate the effects of the electron beam irradiation on the electrochemical reduction of coal.
Abstract: This paper is to examine effects of inherent minerals in coal on N migration and transformation during the fast pyrolysis of Shengli brown coal at the temperatures of 773~1 173 K in a bench-scale fluidized-bed quartz reactor. Based on the comparison between raw coal and acid-washed coal, we can find that the alkali Na and alkaline Ca were the key reasons for the difference in N evolutions from raw coal and demineralized coal during the pyrolysis. The Na and Ca could efficiently facilitate the formation of NH3 and inhibit the production of HCN. The metallic species had obvious catalytic effects for the conversion from tar-N to NH3. Meantime, the existence of alkali and alkaline metals has enhanced the cracking reactions of coal char, thus reducing the yields of char and char-N. In addition, the relative amount of pyridinic(N-6) in demineralized coal char was higher than that in raw coal, while less quternary type nitrogen (N-Q) and pyrrolic nitrogen(N-5) were found in the demineralized coal char.
Abstract: The flotation separation of Shenfu coal macerals and the low temperature pyrolysis characteristics of its concentrates were carried out. The effect of pulp pH value on flotation separation and the impact of maceral enrichment ratio on low temperature pyrolysis were studied. A contrastive analysis was conducted on the characteristics of maceral concentrates in low temperature pyrolysis, providing theory guidance for classifying utilization of coal macerals. The results show that the separation effect of macerals can be manipulated through adjustment of pulp pH value. The more vitrinite exists in the coal sample, the higher the tar yield in low temperature pyrolysis is. But the more inertinite existing in the coal sample highers the semicoke yield. The surface of semicoke from vitrinite concentrates shows clear holes and cracks, and the semicoke structure of inertinite concentrates becomes more dispersive and fragile and an increase in small particles is found. Shenfu coal and its various macerals concentrates show a relative high content of phenols in its tar from low temperature pyrolysis. More phenols, naphthalenes and hydrocarbons exist in the tar from vitrinite concentrates, whereas more cyclophanes and benzenes are found in inertinite tar. The gas compositions of Shenfu coal and its concentrates in low temperature pyrolysis are CH4, H2, CO2 and a bit of C2~5. The relative cumulative yield of CH4, H2, and C2~5 in low temperature pyrolysis gas from vitrinite concentrates is higher than those from inertinite, but the CO and CO2 is lower than that from inertinite. The relative cumulative yield of CH4 and H2 is higher in pyrolysis gas of Shenfu raw coal than that from vitrinite and inertinite.
Abstract: The leaching characteristics of arsenic in fly ash from coal combustion in lab-scale fluidized bed were clarified. Calcium oxide was mixed with fed coal for matching different Ca/S molar ratio to investigate the role of calcium on the leaching behavior of arsenic. The results indicate that increase in Ca/S molar ratio promotes the retention of arsenic in fly ash and in turn reduces its emission. The reaction between CaO and arsenic is largely dependent on the sulfation of CaO. Leaching of arsenic from fly ash is greatly dependent on the pH value of leachate. Alkali fly ash generates a high pH value solution during leaching test, facilitating the prohibition of arsenic leaching. The mechanism of arsenic leaching in alkali fly ash can be described as that arsenic first releases from fly ash quickly and then subjects to the reaction with calcium to form precipitate under high pH value condition.
Abstract: Coal-based activated carbons (ACs) were prepared from HyperCoal using KOH and CaCO3 as activating agent, and were used as electrode materials for electric double layer capacitor (EDLC) using 0.5 mol/L TEABF4/PC as the electrolytic solution. The porosity of the ACs was characterized using N2 adsorption at 77 K. The effects of carbonization temperature, activation temperature, activation time and activating agent on the capacitance characteristic of ACs were investigated. The results show that the specific surface area and the specific capacitance decreased with the increase of carbonization temperature. A high activation temperature and a long activation time is not beneficial for the specific capacitance of EDLC. CaCO3 significantly inhibited the porosity development during KOH activation and gave ACs with quite low specific surface area and specific capacitance. The ACs prepared at carbonization temperature of 500 ℃, activation temperature of 800 ℃, KOH/char ratio of 4 and activation time of 2 h reached a specific surface area of 2 540 m2/g and a total pore volume of 1.65 cm3/g and achieved the maximum specific capacitance of 46.0 F/g.
Abstract: The weight loss characteristics, evolution patterns of volatiles and morphology of solid product from co-pyrolysis of black liquor and petroleum coke were studied by a thermo gravimetric analyzer coupled with Fourier Transform Infrared Spectrometry (TGA-FTIR) and scanning electronic microscopy (SEM). The CO2 co-gasification characteristics of black liquor char and petroleum coke were also investigated by thermo gravimetric analyzer (TGA). The results suggested that the pyrolysis reactions had proceeded independently during co-pyrolysis process at temperatures below 600 ℃. However, as the temperature exceeded 600 ℃, the release peak temperature of CO2 and CO were shifted to low temperature zone, and the thermo gravimetric characteristics were changed in contrast with the separate pyrolysis. Moreover,the surface morphology of the solid products from co-pyrolysis had been changed dramatically at 800 ℃. Specifically, the sintering during pyrolysis of black liquor was inhibited by the presence of petroleum coke. Compared to the individual gasification, the carbon conversion and gasification rate had been greatly improved for CO2 co-gasification due to the synergistic effect of the blends at 850 ℃. The overall carbon conversion were increased by 51.27%, meanwhile, the maximum gasification rate were improved by twice during CO2 co-gasification process.
Abstract: NO reduction through advanced reburning (AR) with biomass including rice husk (RH), phoenix tree leaves (PTL) and saw dust (SD) was tested in an entrained flow reactor (EFR). The effects of reburning fuel species, reaction temperature in the reburning-zone (t2), the location of ammonia injection, water vapor and additives on the NO reduction were investigated. Furthermore, the migration of chloride and potassium elements during biomass advanced reburning was examined. The results indicate that the NO removal efficiency via biomass advanced reburning shows a tendency of increase first and decrease later with increasing the reaction temperature in the reburning-zone from 850 ℃ to 1 150 ℃. The same tendency is also found as SR2 increases from 0.5 to 1.0. The location of ammonia injection has a certain influence on the NO reduction with rice husk when the residence time is in the range of 0.4~1.0 s. The water vapor (0~15%) in the flue gas not only improves the NO removal efficiency, but also broadens the window temperature of DeNOx, and the best NO removal efficiency can be obtained when the water vapor is about 4%. Additives (Fe2O3, KCl, NaCl and CaO) have a better promoting effects on the NO reduction through advanced reburning with rice husk, in which Fe2O3 shows the most significant effect on the NO reduction. The release of chlorine and potassium during advanced reburning with rice husk can reach more than 95.0% and 59.8%, respectively.
Abstract: The carbide slag as a calcium-based waste was calcined and used to remove HCl. The effects of HCl removal reaction temperature, HCl volume fraction, particle size and calcination temperature on the dechlorination performance of carbide slag were examined in a calcination/chlorination reactor. The results show that the carbide slag has the highest chlorination conversion at 700 ℃, and has higher chlorination conversions than limestone at the temperature above 650 ℃. It indicates that the carbide slag has a better dechlorination performance at higher temperature. The chlorination conversion of carbide slag rises linearly with the increasing of HCl volume fraction. As the particle size increases, the chlorination conversion decreases slowly. The calcination temperature above 900 ℃ is adverse to the HCl removal by carbide slag. The calcined carbide slag possesses more pores in the range of 2~10 nm. And after chlorination, the volume and area of pores in 2~10 nm drop by 56.2% and 62.2%,respectively. The pores in 2~10 nm may be the dominating area for the calcined carbide slag to absorb HCl.
Abstract: The esterification process of acidified oil with glycerol was thoroughly investigated by varying reaction temperature, molar ratio of glycerol to the free fatty acids in oil and the monoglyceride content in starting materials. It is found that monoglyceride can significantly promote the reaction process and lead to a much lower content of fatty acids in the product. This is elucidated by the additional analysis of experimental liquid-liquid equilibrium data for the binary systems of triglycerides-glycerin, oleic acid-glycerol and monoglyceride-glycerol, as well as the ternary phase diagram of glycerol-monoglyceride-oleic acid system. The comparison between the above ternary and binary systems clearly indicates that the appearance of monoglyceride remarkably improves the solubility of both glycerol and fatty acids in its counter phase, which can account for the observed promotion effect of monoglyceride in the esterification process of acidified oil.
Abstract: The effect of oxidation pretreatment temperature (500~1 000 ℃) on the catalytic activity of Kovar applied on hydrocarbon CO2 reforming was examined. Catalytic performance evaluation using tetradecane at 800 ℃ with 70 μmol/s CO2 revealed 700 and 1 000 ℃ as the best pre-oxidation temperature in producing CO and H2, respectively. XRD and SEM-EDX analyses showed that a separate metal oxide layer composed of iron oxide (Fe2O3 and F3O4), nickel, cobalt, and possibly their respective oxides started to form when oxidation was conducted at 700 ℃ or higher.The presence of iron enhanced the stability of nickel in the structure while the compact structure of Fe3O4 resulted into the formation of a thick and rigid metal oxide layer on the surface of the Kovar tube. The strong physical bond between the metal oxide layer and Kovar tube provided the catalyst good mechanical strength and consequently good catalytic activity.
Abstract: Dispersion corrected density functional theory (DFT-D2) were employed to investigate the distribution of Al in the framework of H-[Al]MOR and the strengths of Brönsted acid sites by NH3 adsorption. Thermodynamically, the most favorable site for distribution of Al is T2O5, followed by T4O2, T1O7 and T3O1, which are a little higher in energy when Al is incorporated. It was found that the energy differences for Al in different T sites are 0.03~ 0.07 eV, indicating that the Al atoms might distribute in all kinds of four non-equivalent crystallographic tetrahedral sites of MOR. Moreover, it is also suggested that the location of protons plays an important role in the stability of the Al substitution site. In addition, we also computed the adsorption energies for NH3 adsorbed at each crystallographic position of H-[Al]MOR by DFT and DFT-D2, respectively. By comparison, the DFT method always underestimates the substitution energy by 0.41 eV for the adsorption of NH3, indicating that the dispersion correction is necessary to calculate the adsorption of NH3 in H-[Al]MOR. The results show that the Brönsted acid site at T2O5 is stronger than the other acid sites, and the adsorption of NH3 on the Lewis acid sites is clearly weaker than on the Brönsted acid sites.
Abstract: With nickel nitrate and nickel acetate as nickel precursors, a series of Ni/SBA-15 catalysts were prepared by using the impregnation method and activating in air or hydrogen atmosphere. The Ni/SBA-15 catalysts were characterized with XRD, H2-TPD, N2 physisorption and online mass spectroscopy. Their catalytic properties were evaluated with hydrogenation of naphthalene as a model reaction. It was shown that activation in hydrogen greatly increased the Ni dispersion and catalytic activity of Ni/SBA-15 prepared with nickel nitrate, while activation in air significantly improved the sample prepared with nickel acetate. In terms of the thermal decomposition products of the catalyst precursors activated in different atmospheres, the affecting mechanism of the activation atmosphere on the Ni/SBA-15 catalysts prepared with different nickel precursors was proposed.
Abstract: Using attapulgite clay(APT) as the support, the catalysts Pd-Cu/APT were prepared by wet impregnation method. The effect of calcination temperature on the catalytic performance for CO oxidation at room temperature was investigated in a fixed-bed continuous flow reactor. Structure and property of the catalysts were characterized by N2-physisorption, XRD, TG, FT-IR and H2-TPR. The results showed that as the calcination temperature increased, structure and texture of the catalysts changed due to the desorption of water in the support. Cu species changed from Cu(OH)Cl to CuO gradually, while interactions between highly dispersed Pd and Cu species increased firstly and then decreased. The catalyst calcined at 300 ℃ possessed the highest surface area, dispersed Cu(OH)Cl, and strong interaction between Pd and Cu species, which significantly improved the reducibility of the catalyst. At the reaction conditions of CO 0.5%, GHSV 6 000 h-1, water content 3.3% and room temperature, the catalyst was able to maintain its activity for CO complete oxidation more than 800 min. Calcination temperatures higher or lower than 300 ℃ caused the lower catalytic activity.
Abstract: A series of CeO2/CuO catalysts were prepared by surfactant-template method and characterized by high resolution transmission electron microscope (HRTEM), X-ray diffraction (XRD), temperature-programmed reduction (H2-TPR) and N2 sorption; their catalytic performance for preferential oxidation of CO (CO-PROX) in H2-rich stream was investigated. The results show that the 4 nm CeO2 particles with cubic fluorite structure are agglomerated into small clusters and dispersed on the bulk CuO; CeO2/CuO may belong to a type of reverse supported catalyst on the basis of particle size distribution. There are two kinds of active sites in the CeO2/CuO system, i.e. the CuO sites for CO chemisorption and the CeO2 sites supplying oxygen vacancies; the coexistence of two-kind surface sites on the contact interface is capable of promoting the preferential oxidation of CO.
Abstract: N-(3-Sulfopropyl) pyridinium methanesulfonate ionic liquid was immobilized on HZSM-5 molecular sieves by chemical method and used as the catalyst in the synthesis of polyoxymethylene dimethyl ethers (PODEn). X-ray diffraction, infrared spectroscopy and N2 sorption results showed that the ionic liquid is well immobilized on the molecular sieves. The optimized reaction conditions for the synthesis of PODEn distributions are obtained, i.e. m(ionic liquid)/m(HZSM-5) = 0.25, n(CH3OH)/n((CH2O)3) = 1.5, 2.2% catalyst, 110 ℃ and 3 h. Under these conditions, the yield of PODE3~8, as the ideal additives for diesel fuel, reaches 67.35%, which is much higher than those with single ionic liquid or molecular sieve as the catalyst. The immobilized ionic liquid can be easily recycled and reused; the yield of PODE3~8 remains up to 45.62% after reused for three times.
Abstract: Na-B-ZSM-5 molecular sieves were synthesized by hydrothermal method with silica white as silicon source, boric acid as boron source, sodium hydroxide as alkali, and tetrapropylammonium bromide (TPABr) and 1,6-hexamethylenediamine (HMDA) as the hybrid template. The synthesized Na-B-ZSM-5 samples were characterized by XRD, SEM, FT-IR, UV-vis, 11B MAS NMR and NH3-TPD. Their catalytic performance in methanol dehydrogenation to formaldehyde was evaluated in a fixed-bed reactor under atmospheric pressure and the effects of the catalyst preparation parameters like Si/B molar ratio, basicity, crystallization temperature and crystallization time as well as the reaction conditions like temperature and space velocity (WHSV) on the methanol dehydrogenation behavior were investigated. The results indicated that boron atoms are introduced into the framework of Na-B-ZSM-5 molecular sieves, present as the Bronsted acid sites from four-coordinated boron atoms and Lewis acid sites from tricoordinated boron atoms. Na-B-ZSM-5 molecular sieves contain more weak acid sites and less middle-strong acid sites. The optimized preparation parameters of the Na-B-ZSM-5 molecular sieve are as follows: 7.5 of Si/B molar ratio, 0.14 of Na2O/SiO2 molar ratio, 170 ℃ of crystallization temperature and 48 h of crystallization time. The conversion of methanol and the selectivity to formaldehyde reach 62.97% and 68.86%, respectively, under the reaction conditions of 550 ℃ and a WHSV of 1.85 h-1 over the optimized Na-B-ZSM-5 molecular sieve.
Abstract: Highly crystalline SAPO-53 molecular sieves were successfully synthesized under a hydrothermal condition by using hydroxide hexane dual ammonium(R(OH)2) as a template. The samples were characterized by a serious of techniques,including XRD,SEM-EDX,FT-IR,MAS NMR,electrophoresis apparatus,N2 adsorption-desorption and TG-DTG. Various preparation conditions including Si/Al ratio, P/Al ratio, the amount of template and crystallization time for the synthesis of SAPO-53 molecular sieves have been systematically studied. It shows that Si has entered the AlPO4-53 framework mainly with a form of four ligand detected by 29Si MAS NMR. The results reveal that the relative crystallinity of synthesized samples increases firstly and reduces afterward with the increase of time,while the Zeta potential value increases first and then remains unchanged. Compared with the synthesis taking methylamine as a template, the template agent of hydroxide hexane dual ammonium is only half of the amount for the sample synthesis. Furthermore, this method can shorten the crystallization time and reduce the difficulty of synthesis. The apparent growth rate of SAPO-53 molecular sieve is higher than its nucleation rate through the calculation, so the nucleation process is the rate controlling step.
Abstract: The Cu/γ-Al2O3 catalysts with 11.32% copper contents prepared by the incipient wetness impregnation were tested in a fixed bed reactor. The effects of SO2 concentration (0 ~ 0.02%) on the combustion characteristic and stability of low concentration methane (3%) over Cu/γ-Al2O3 catalysts were investigated. By the analysis of microstructure and chemical component of fresh and aged catalysts, the mechanism of sulfur poisoning in the catalytic reaction was discussed by combining with the theoretical analysis. The results show that the addition of SO2 in the feed gases leads to a decrease of activity and stability of the catalysts. The methane conversion decreases rapidly with the increasing concentration of SO2. The results of SEM, EDS, FT-IR and XRD reveal that the presence of SO2 in the feed gases can result in agglomeration and accumulation of sulfur on the surface of Cu/γ-Al2O3 catalysts. Sulfur is in the form of sulfate, which mainly contains copper sulfate (CuSO4). Under the condition of oxygen enrichment, the copper sulfate produced by the absorption of SO2 and oxygen ions on Cu2+ is attached to the surface of catalysts and forms a hard shell, which is the major reason for the sulfur poisoning.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
