Search

Cu I Y catalyst was prepared by heating the mixture of CuCl 2 and acidic Y zeolite under flowing nitrogen and characterized by TG/DTG, XRD and elementary analysis techniques. The experimental result indicate that when the heating temperature was from 350 °C to 500 °C, the CuCl 2 of the CuCl 2 and acidic Y zeolite mixture sample decompose to CuCl and Cl 2 gas, then the produced CuCl reacted with the Bronsted acid center H + of Y zeolite to form Cu I Y catalyst by the solid-state ion-exchanged reaction. The amount of ion-exchanged Cu I in the Cu I Y catalyst reached the maximum of 0.1 mol/g when the heating temperature was 650 °C, and the catalyst exhibited the best catalytic activity, the conversion of methanol ( C MeOH ), the selectivity and the space–time yield of dimethyl carbonate ( S DMC and STY) reached 4.36%, 74.55% and 97.32 mg/(g h), respectively.

Summary The extract yields obtained by three methods in different solvents from chilli were compared. The antioxidant activities of chilli extracts vs. butylated hydroxytoluene (BHT) was determined through the peroxide value (POV), the beta-carotene bleaching assay and the 2,2-diphenyl-1-picrylhydrazyl radical scavenging method. The results showed that the extract yields by three extract methods, namely, Soxhlet, ultrasonic wave and saturation, were 16.32%, 15.78% and 11.62%, respectively, when 85% ethanol acted as solvent. The extracting efficiency of solvent from high to low was 95% ethanol > ethyl acetate > anhydrous ethanol > distilled water. The total phenol content of chilli extracts from ultrasonic wave with 85% ethanol as solvent was 73.91 mg gallic acid equivalents (GAE) per gram extracts and the value of inhibitory capacity IC50 on free radical (DPPH) was 38.99 mg mL−1. The POV of chilli extracts was close to that of BHT. The ultrasonic wave was more helpful for the extraction of antioxidant substance from chilli than other methods. In addition, the composition of chilli extracts was analysed by gas chromatography-mass spectrum (GC-MS).

The Zr-SBA-15 mesoporous materials with high Zr/Si ratio (0–2.32) were first synthesized directly using zirconium nitrate and tetraethyl orthosilicate as precursor, displaying higher thermal stability after activated at 600 °C. 29Si NMR spectra revealed the part existance of ZrO2 in the framework of SBA-15. After sulfated, the SO 4 2 - / Zr-SBA- 15 exhibited high activity in the isomerization of n-pentane at 35 °C, and the conversion of n-pentane reached 93.9% after reacting 180 min with the SO 4 2 - / Zr-SBA- 15 of Zr/Si = 1.3, which was higher compared with the bulk sulfated zirconia material and the SBA-15 modified with SO 4 2 - / ZrO 2 by incipient wetness method.

The coking observation and particle flow behaviour in both thermal plasma and cold plexiglas downers were investigated in a binary particle system formed by injecting coarse inert particles (carrying coke away and scouring wall) and fine coal powders into the downer reactor. The results demonstrate that this scheme is a rational selection to prevent coking on downer walls and improve particle velocity distribution along the radial direction. When injected coarse particles mixed with fine powders in downers, the fluctuation of local particle velocity in the radial direction becomes smaller and two peaks in the radial distribution of local particle velocity occur due to the improved dispersing character and flow structure, which are beneficial to the thermo-plasma coal cracking reaction and coking prevention.

The apparent kinetics of H 2 S removal by ZnO in the presence of hydrogen were studied by thermogravimetric analysis. Experiments were carried out with spherical pellets of about φ 3 mm, at temperatures from 200 to 320°C. For the purpose of comparison, experiments were also carried out in the absence of hydrogen. The results show that the kinetic behavior of the desulfurization could be described by the equivalent grain model. The activation energies of reaction and diffusion in H 2 S–N 2 and in H 2 S–N 2 –H 2 systems were estimated and compared. The effect of hydrogen on desulfurization was also investigated.

Coal undergoes a series of complex physical and chemical changes during pyrolysis. These changes have something to do with coal structure. In this paper, the features and kinetics of five kinds coal pyrolysis were investigated, respectively, by a TGA system in a stream of Nitrogen and Argon with a heating rate of 20 K/min up to 1173 K. The chemical structures of these coals were examined by the FT-IR technique, and their microcrystalline structure was measured by the XRD technique. The results showed that the pyrolysis of five coals consists of three stages; the second stage is the strongest pyrolysis stage. The characteristic temperature T0.05 and T0.5 are different for five coals and are affected by their chemical structure, microcrystalline structure parameter, volatile matter (Vd) content, and environmental atmosphere. The pyrolysis active energy E and preexponential factor A in the second reaction stage have a compensation effect, and they are affected by coal structure and reaction atmosphere.

In order to understand the factors influencing limestone capturing sulfur during coal combustion and improving its capacity, a series of tests were conducted under different reaction condtitions. The results show that the relation between limestone desulfurization and Ca/S (mol/mol) ratio varies with reaction temperature. The capacity of limestone capturing sulfur arrived at optimum when Ca/S is 1.5 at constant high temperature of 1080°C and the capacity of limestone capturing sulfur increases with temperature rising in the range of 25°C ~ 1080°C programmed temperature. The capacity of limestone capturing sulfur decreases with N2 content increasing in reaction gases and increases with suitable additives adding to limestone. The raw samples and the residuals after sample combustion were analyzed by EA and TG-DTA techniques.

Four kinds of rare earth oxides, lanthana, ceria, praseodymia and neodymia were separately added as promoters to nickel catalyst (Ni/γ-Al2O3). The nickel catalysts formed, NRL, NRC, NRP, NRN, have a typical structure of mezzanine that is unfit for carbon deposition on nickel catalyst. Ni−Nd/γ-Al2O3 shows higher selectivity for carbon-free operation.

Macerals of NW coal were separated by isopycnic density gradient centrifugation (IDGC) (ZnCl2 was used as density fluid) and each macerals were undertaken forms of sulfur. Sulfur was removed by peroxyacetic acid-oxidation under ultrasonic and microwave radiation. Transformations of organic sulfur forms were expressed by XPS spectra. The results showed that forms of organic sulfur were enriched in different macerals, thiophenes in vitrinite and thioethers, thiols in exinite. Desulfurization rate of NW raw coal was up to 38.1% with peroxyacetic acid under ultrasonic and microwave radiation. From easy to difficult, the order of desulfurization of each macerals was the same as mineral and inertinite > inertinite > exinite > vitrinite, the most high desulfurization rate of macerals was 53.1%.