Abstract: Xianfeng lignite (XL) was firstly thermal dissolved in the isometric toluene/methanol mixed solvent at 300℃ in a stainless-steel autoclave to afford a soluble portion (SPXL) and a residue (RXL), then the nitrogen forms in XL and RXL were characterized with X-ray photoelectron spectroscopy (XPS) analysis, and the nitrogen-containing species (NCSs) in SPXL were identified using gas chromatography/mass spectrometry (GC/MS) and electrospray ionization Fourier transform ion cyclotron mass spectrometry (ESI FT-ICR MS) analyses. The results show that the amount of nitrogen forms in XL is in the order of quaternary-N>pyridinic-N>pyrrolic-N, while quaternary-N in XL is easily dissolved out during thermal dissolution. In total 20 NCSs were detected in SPXL by GC/MS, and most of them are amines. Over three hundreds of NCSs were identified in SPXL by ESI FT-ICR MS, and most of them are the NCSs containing one or three nitrogen atoms. The NCSs containing one nitrogen atom are mainly dominated by N1O1, N1O2 and N1OxS1-2 class species, while most of NCSs containing three nitrogen atoms are N3OxS1-2 class species (x=1-12). The double bond equivalent (DBE) values and carbon number of the NCSs containing one nitrogen atom increase with increasing number of oxygen atoms.
Abstract: In this research, a solid 1%Li/Ca-La mixed oxide catalyst was prepared using co-precipitation method followed by wet impregnation. The prepared catalyst was used in the transesterification reaction of canola oil and methanol for biodiesel synthesis. The effects of calcination and reaction temperatures were investigated on the activity of the catalyst. In addition, rate of the reaction was studied through a kinetic model for which parameters were determined. Surface properties and structure of the catalyst were characterized through the powder X-ray diffraction (XRD), thermogravimetry/derivative thermogravimetry (TG/DTG), and Fourier transform infrared spectroscopy analysis. All these emphasized that the performance of the catalyst corresponded to the generation of the active sites and their thermal activation.
Abstract: The leaching behaviors of aluminum in ash from combustion and catalytic gasification, and effects of Na2CO3 addition (0-15%), temperature (600-1 000℃) on Al leaching behaviors and mineral composition were investigated. The compositions of ash from combustion and gasification, and acid leaching residue were investigated by XRD. The results shows that the combustion ash is predominantly composed of mullite, while that from catalytic gasification is sodium aluminum silicate ((Na2O)0.33NaAlSiO4). The Al extraction yield of combustion ash only reaches 40% at leaching conditions of 6 mol/L H2SO4, 60℃ and 30 min, while that of catalytic gasification ash with 10% Na2CO3 addition can reach 88%. The catalytic gasification with Na2CO3 addition can achieve higher Al extraction yield.
Abstract: The effect of the electrochemical treatment on the surface structure and flotability of the macerals in Shenmu coal was studied, which aimed to provide a theoretical foundation for the separation by electrochemical flotation. The influence of anode and cathode on the surface structure, surface potential and wettability of Shenmu vitrinite and inertinite was investigated. The results show that the electrochemical treatment has a significant effect on the oxygen-containing functional groups of coal macerals such as-OH, -COOH, etc. The surface zeta potential of macerals moves towards the electronegativity and the wettability of macerals increases when the treatment is conducted with electrochemical anode. However, the surface zeta potential of macerals moves towards the electropositivity and the wettability decreases when the electrochemical cathode is used. The variation trend of contact angle for the vitrinite treated with electrochemical anode is more obvious, while the inertinite treated with electrochemical cathode is more conspicuous.
Abstract: Eight coal chars of different coal ranks were prepared to investigate the effects of coal rank, reaction temperature and particle size on char-CO2 gasification using a thermogravimetric analyzer (TGA). The variation of char-CO2 gasification rate with carbon conversion was studied, especially at high conversion stage. As a result, the crystalline structures of higher rank chars are more orderly, resulting in a lower gasification rate. For high rank coals like anthracite, the CO2 gasification rate of char with 40 μm size is about 7 times higher than that with 300 μm size to reach 95% conversion at 1 300℃. For low rank coals, particle size has little effect on the gasification rate. The results indicate that the effect of particle size on char-CO2 gasification is dependent on coal rank. The specific surface area of high rank coals is much smaller than that of low rank coals, which contributes to the significant effect of particle size on high rank coal gasification. The effect of gasification temperature and particle size on gasification rate for high rank coals is more significant than that for low rank coals.
Abstract: The impact of Na content on nitrogen transformation during the pyrolysis of Shengli raw coal and the Na-loaded coal in a fixed-bed/fluidized-bed quartz reactor was investigated. The quantification of NH3 and HCN in gas product was carried out using an ultraviolet-visible spectrophotometer while the occurrence modes of nitrogen in the solid chars were detected by X-ray photoelectron spectroscopy (XPS). The results indicate that the transformation of coal-N to NH3 can be catalytically enhanced by certain amount of Na at low temperature. When the final pyrolysis temperature is relatively high, the presence of Na appears to inhibit the formation of NH3. Meanwhile, for any given pyrolysis temperature, the production of HCN will be suppressed by Na. When the pyrolysis temperature is high, the increase of Na content in coal causes the reduction of nitrogen remaining in char and promotes quaternary nitrogen formation, whereas, the effect is negligible at low temperature.
Abstract: The rapid pyrolysis experiments of Shenfu coal with various moisture content prepared by adding water were conducted in a high-frequency furnace to study the influence of moisture content on the thermal behavior. The gas composition and the structure properties of char were analyzed. The result shows that the gas yield and the maximal release rate decrease when the moisture content of coal increases. After pyrolysis, both BET surface and pore volume increase with increasing moisture. Compared to the char from dry coal pyrolysis, the char from pyrolysis of coal with high moisture content has more developed pore structure with more micropores. Furthermore, the moisture can inhabit the occurrence of pore obstruction and collapse during rapid pyrolysis, and also contribute to the enhancement of the surface roughness and the pore structure complexity.
Abstract: Anhui lignite, Liaoning lignite and Guizhou bitumite were co-processed with Murray residue (MRAR), Karamay residue (KAR) and FCC slurry (FCCS) in an autoclave with molybdenum naphthenate as catalyst, simulating the slurry-phase hydrogenation co-processing. The results show that for two lignites under different oil systems, the conversion of coal exceeds 83%. However, for Guizhou bitumite, a great difference is observed in the coal conversion between FCCS (67.75%) and KAR (50.31%) for co-processing. The solid residues after co-processing were analyzed by FT-IR and SEM, to determine the relative content of aliphatic and aromatic groups and the micro morphology. It is found that the solid residue derived from the KAR system possesses a low content of CH2/CH3 and a low substitution degree. Moreover, the solid residues obtained from two lignites with high coal conversion exhibit a looser structure and a higher dispersion of solid particles than that from bitumite with a low coal conversion.
Abstract: The influence of CeO2 as an additive on the carbonaceous deposition behavior of Ni-Cu/H-ZSM-5 catalyst in the hydrodeoxygenation (HDO) of bio-oil was investigated. Various techniques such as thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy were used to elucidate the content and microstructure of carbon deposited on the catalyst surface, the transformation of various forms of carbon (soft carbon, hard carbon and graphite) in HDO, and the kinetics of carbon deposition. The results indicate that the content of CeO2 added in the Ni-Cu based catalyst and the reaction temperature both have a significant influence on the carbon deposition behavior and the resistance against coking for HDO of bio-oil; for HDO over the Ni-Cu/HZSM-5 catalyst at 270℃, adding 15% CeO2 gives the Ni-Cu catalyst highest resistance against the carbon deposition.
Abstract: The N, P-doped C@Mo2C catalysts were prepared using melamine benzoate as the source of nitrogen and carbon, melamine phosphomolybdate as the source of phosphorus, nitrogen and molybdenum, respectively. The surface structures of the prepared catalysts were characterized by XRD, SEM, TEM and XPS. The effects of the ratio of benzoic acid to melamine in melamine benzoate and n(C)/n(Mo) of the precursor on the catalysts were investigated. The activity of the catalysts was evaluated by using CO2 hydrogenation as a model reaction in a fixed-bed reactor, in which a mixed gas of CO2/H2 (VH2:VCO2=3:1) was used as the feed gas, and it was found that the N, P-doped C@Mo2C showed a good catalytic performance with CO2 conversion of 12.2% and methanol selectivity of 52.2% under the optimal reaction conditions (reaction temperature 220℃, reaction pressure 3.0 MPa, space velocity 3 600 mL/(g·h).
Abstract: Beta zeolites were successfully synthesized via hydrothermal method using sodium aluminate as aluminium source, silica sol (Ludox) as silicon source and TEAOH as template, respectively. The effects of different additives polyvinyl pyrrolidone (PVP) and Methyltriethoxysilane (MTS) on their structural properties and synthesis mechanism were investigated in detail by various characterizations, such as XRD, TEM, BET, ICP, 29Si-NMR and NH3-TPD method. Also, their catalytic performances were evaluated through catalytic cracking of cumene. The results showed that the beta zeolite obtained in the PVP-added system presented a better crystallinity, higher Si/Al molar ratio (25.68), and larger surface area (772 m2/g). Comparably, the MTS-effected samples revealed a larger surface area (657 m2/g), higher Si/Al molar ratio (25.76), but lower crystallinity and smaller particle sizes (around 160-320 nm). Moreover, both of them exhibited a good catalytic activity for cumene cracking due to the existences of abundant and strong acid content.
Abstract: Pd and Pd-Ag nanoparticles supported on multi-walled carbon nanotubes (MWCNT) were prepared by using the NaBH4 reduction method in a mixed solvent of ethylene glycol and water; their catalytic activity for the electro-oxidation of ethanol, n-propanol and iso-propanol was investigated in alkaline media by the voltammetric method. The results indicate that Pd and Pd-Ag nanoparticles are well-dispersed on the surface of MWCNTs and the average sizes of metal particles on the Pd/MWCNT, Pd4Ag1/MWCNT, Pd2Ag1/MWCNT and Pd1Ag1/MWCNT catalysts are 7, 4, 7 and 11 nm, respectively. Over these catalysts, the electro-oxidation of n-propanol exhibits larger current density than the oxidation of ethanol and iso-propanol. Moreover, the binary PdnAg1/MWCNT catalysts (n=4, 2, 1), especially Pd4Ag1/MWCNT, gives higher current density for the oxidation of ethanol and propanols than the Pd/MWCNT catalyst, suggesting that the addition of Ag can enhance the activity of Pd-based catalyst for the electro-oxidation of alcohols. The excellent activity of binary Pd-Ag/MWCNT catalysts is probably attributed to the weak absorption of intermediate species on Pd due to the interaction between Pd and Ag, which may promote the oxidation of alcohols.
Abstract: The metal-organic framework MIL-101(Cr) was synthesized via hydrothermal process and then modified with pentaethylenehexamine (PEHA) through refluxing in ethanol. Various measures such as SEM, XRD, N2 sorption, Elemental analysis and FT-IR were used to characterize the structure, morphology and properties of PEHA-grafted MIL-101(Cr). Meanwhile, the performance of PEHA-grafted MIL-101(Cr) in CO2 adsorption was investigated under 25℃. The results illustrate that the loading of PEHA in MIL-101(Cr) can conspicuously enhance the CO2 adsorption capacity. PEHA-grafted MIL-101(Cr) with a PEHA loading of 0.24 mL exhibits the highest capacity for CO2 adsorption; the adsorption capacity reaches 58.944 mg/g at 25℃ and atmospheric pressure, which is 33% higher than that of the unmodified MIL-101(Cr) (44.208 mg/g). In addition, the CO2 adsorption capacities on both MIL-101(Cr) and PEHA-MIL-101(Cr) are greatly enhanced by increasing pressure, reaching 1 147.59 and 1 256.74 mg/g at 1.1 MPa, respectively. These results suggest that PEHA-modified MIL-101(Cr) could be a good candidate adsorbent for CO2 capture at high pressure.
Abstract: Low-temperature selective catalytic reduction (SCR) catalysts were prepared by step wise blending method with TiO2, TiO2-Al2O3 and TiO2-SiO2 as support and Mn as active component, Ce as promoter. The effects of doping Al2O3 and SiO2 to TiO2 support on NOx removal activity of the catalysts were systematically investigated. The catalysts were characterized by XRD, BET surface area, SEM, H2-TPR and NH3-TPD. It was found that the specific surface area, pore structure parameters and surface pore structure morphology of the catalysts were improved and the TiO2 crystallinity of Mn-Ce/TiO2-Al2O3 and Mn-Ce/TiO2-SiO2 catalysts were reduced to some extent by doping SiO2, Al2O3 on TiO2 support respectively. The low temperature reduction peak area, acid type and acidity of catalysts surface were improved significantlybydoping modification. All of these were beneficial to enhance the denitration activity of the catalysts. The denitration activity of the catalysts was increased to a great extent by doping SiO2 and Al2O3 on TiO2 support respectively, the order of SCR activity of three kinds of catalysts above was:Mn-Ce/TiO2-SiO2 > Mn-Ce/TiO2-Al2O3 > Mn-Ce/TiO2 when the SCR reaction temperature was in the range of 80-140℃.
Abstract: Transition metal M(M=Mn, Co, Fe and Cu) modified amorphous CeO2@TiO2 catalysts were prepared via a spontaneous deposition strategy. The low-temperature deNOx activity of M-CeO2@TiO2 for selective catalytic reduction was investigated. XRD, TEM, N2 adsorption-desorption, H2-TPR, NH3-TPD and in-situ FT-IR were used to study the structure, surface property and low-temperature NH3-SCR reaction performance of M-CeO2@TiO2. The results showed that the M-CeO2@TiO2 had better low-temperature oxidation reducibility and more surface acid. Cu doping had the most significant promoting effect on low-temperature deNOx activity for selective catalytic reduction. During the low-temperature NH3-SCR reaction, both the L-H and E-R mechanisms existed over the Cu-CeO2@TiO2 and the L-H mechanism could play a pivotal role due to the "fast SCR"process.
Abstract: The experiments were conducted in a bench-scale fluidized-bed reactor. To improve the reactivity of hematite, cement was added. The results show that cement-modified hematite possessed a higher reactivity, leading to an increase in carbon conversion of sewage sludge. Nevertheless, the NO emission also increased as compared to hematite alone. The rise of fuel reactor temperature can intensify both carbon conversion and NO emission. Meanwhile, the rise of steam content can increase carbon conversion and decrease NO emission. Approximately 0.286%-0.768% of nitrogen measured was NO, which is lower than the value in sewage sludge air incineration process.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
