Advanced Materials Research Vols. 512-515

Abstract: Phosphomolybdic acid loaded on SiO₂ has been prepared as the catalyst by the sol-gel method. The catalysts were evaluated for the oxidative desulfurization of model fuel oil using hydrogen peroxide as an oxidant. Results show that the calcined temperature, Mo/Si molar ratio, catalyst dosage, H₂O₂ dosage, reaction temperature and reaction time affect the desulfurization rates. The oxidative reactions fit apparent first-order kinetics, and the apparent activation energies of BT and DBT are 51.87 KJ/mol and 25.79 KJ/mol, respectively.

Abstract: The co-pyrolysis process of coal and waste plastics was studied. Changing and transferring property of chlorine in the process was investigated. There was synergistic effect between coal and waste plastics when chlorine was released, which resulted in increase of chlorine in tar and decrease in coke. The effect of waste plastics’ amount on chlorine releasing property varied with the amount of waste plastics in the sample and the time of constant temperature at the same final co-pyrolysis temperature (such as 950 oC). Using the distributional function of chlorine, the distribution of chlorine in coke, tar and gas was studied. The results indicated that the distribution of chlorine in the co-pyrolysis process could be controlled to a certian extent by controlling the percentage of waste plastics and the time of constant temperature. The amount of chlorine redistributed in coke decreases with the increase of constant temperature time and increased with the increase of the percentage of waste plastics. On the contrary, the chlorine in tar increased with the increase of the constant temperature time and the percentage of waste plastics. And the chlorine redistributed in gas increased with the increase of the constant temperature time, but it decreased when the percentage of waste plastics increased. Additionally, the mathematical model of chlorine changing and transferring rule was established.

Abstract: In this paper, we focused on the determination of phase equilibrium conditions of hydrates formed in the pore water and porous media from South China Sea. High pressure differential scanning calorimetry (HP DSC), a relatively new thermo-analytical technique was applied to this research. During the study, nitrogen hydrates and methane hydrates phase equilibrium conditions were determined in thewater-hydrates- gas (W-H-G) system. Then a series of experiments were carried on using core sample drilled from South China Sea to determine the phase equilibrium properties in pore water and porous media systems. It show that the hydrates phase equilibrium point is about 2K lower than in pure water from pressure range 10 to 30 MPa, due to the thermodynamic inhibition effect of brine solution.

Abstract: The mechanical properties were investigated of a series of PA-PEG thermalplastic elastomer based on PA1010 and polytetramethylene glycol (PEG) with varying hard and soft segment content. Dynamic mechanical measurements of these polymers have carried out over a wide range of temperatures. The block copolymers exhibit three peaks, designated as α, β and γ in the tanδ-temperature curve. The α transition shifts to higher temperature with increasing hard block molecular weight. However, at a constant hard molecular weight, the α transition shifts to higher temperature and the damping increases on increasing the soft segment molecular weight. DMA results show that the block copolymers exhibit a microphase separation structure and both soft and hard segments were found to be crystallizable. The degree of phase separation increases with increasing hard block molecular weight.

Abstract: By using copper manganese sulfated and lanthanum nitrate as raw materials, and NaOH as precipitating agent, the copper-manganese-lanthanum mixed oxides were prepared through co-precipitation method. The catalyst samples were characterized by XRD, TPR and TPD, and the catalytic properties on water gas shift (WGS) reaction were studied. The results show that, La doping didn’t change the crystal structure, but the sample crystallinity was deteriorated. Cu-Mn/La-0.5 sample reduction temperature was low and the adsorption quantity of activated CO2 was large, which implied that copper and manganese components have good metal synergic effect, lower temperature activity and thermal stability.

Abstract: A computational fluid dynamics (CFD) model of a 600 MW opposed swirling coal-fired utility boiler has been established. The chemical percolation devolatilization (CPD) model, instead of an empirical method, has been adapted to predict the nitrogen release during the devolatilization. The current CFD model has been validated by comparing the simulated results with the experimental data obtained from the boiler for case study. The validated CFD model is then applied to study the effects of ratio of over fire air (OFA) on the combustion and nitrogen oxides (NOx) emission characteristics. It is found that, with increasing the ratio of OFA, the carbon content in fly ash increases linearly, and the NOx emission reduces largely. The OFA ratio of 30% is optimal for both high burnout of pulverized coal and low NOx emission. The present study provides helpful information for understanding and optimizing the combustion of the studied boiler

Abstract: The influence of ethylenediamine (en)/Co molar ratio on the preparation of Co/SiO₂ catalysts was studied. The decomposition of these Co-en species resulted in the formation of small cobalt nanoparticles. The highly dispersed catalysts led to lower FT activity due to an increase of cobalt-silica interaction except Co(en)₂/SiO₂ catalyst. Meanwhile, higher selectivity for light hydrocarbons was observed, which was ascribed that smaller cobalt particles containing active sites depressed the chain growth.

Abstract: Fusion characteristics of ash residues from Xiaolongtan lignite pressurized fluidized-bed gasification were investigated with ash fusion point detector and sintering temperature analyzer. The results show that the sintering temperature (Ts) and ash fusion temperature (AFT) of three ashes residues decrease from gangue ashes to agglomerate to slag, which result from the differences of mineral type and content in three ash residues, and the decrease of the total basic constituents increases the AFT. The formations of three ash residues during gasification are the interactions among mineral matter and their transformations under high temperature.

Abstract: Caragana is an abundant plant as the feedstock of biomass energy in China. In this study, pyrolysis of Caragana in the presence of high temperature medium and characterization of products has been carried out. Evaluation of experimental results showed that faster devolatilization and char with increased surface area obtained in the presence of high temperature steam comparing to N₂. Analysis of the obtained liquid revealed that the H/C and O/C ratios in the liquid are 1.5 and 0.16 respectively. Further more gas composition during high temperature steam pyrolysis differs from gas composition derived from N₂ pyrolysis which indicates interaction of steam with vapors and solid species even at low treatment temperatures. The derived products’ yields and characteristics indicate possible exploitation of derived char as activate carbon precursor. Liquid fraction composition makes it suitable for exploitation as liquid fuel and/or chemical feedstock.

Abstract: Oil shale is a combustible, organic solid rock with high ash content, and is one of the most promising alternative energy sources in the world. Pyrolyzing oil shale can yield a number of petroleum products useful as fuels, and the extraction of oil from oil shale is relatively expensive and uneconomical. The plastics had the synergistic effect to enhance shale oil yields by copyrolysis of oil shale/plastics mixtures. The synergistic effect of polyethylene was more obvious than the poly- propene. The more obvious synergistic effect was, the more obvious shale oil yields increased.