Advanced Materials Research Vols. 953-954

Abstract: In this paper, the effects of thermal treatment and acid treatment on the performance of graphite felt for vanadium redox flow battery (VRB ) were investigated by cyclic voltammograms, polarization curves and AC impedance measurements. Both thermal treatment and acid treatment can improve the activity of graphite felt and the thermally treated graphite felt exhibited better activity and reversibility for both positive and negative electrodes of vanadium redox flow batteries. Results from polarization curves analysis showed that the polarization resistivity of thermally treated graphite felt was reduced by 45.5% compared to raw graphite felt while the polarization resistivity of graphite felt became larger after acid treatment. The results of AC impedance measurement revealed that charge transfer process were the control step of the electrode reaction and the thermally treated graphite felt had a lower reaction resistance compared to graphite felt with acid treatment.

Abstract: In view of the oil well scaling phenomenon and the disadvantages of existing pickling descaling, the alkaline detergent which can be used in oil well was prepared. The effect factors of the alkaline detergent were studied. The results show that the alkaline detergent in ASP Flooding has certain descaling effect on different composition of scale. The descaling effect of the carbonate is better than that of silicon aluminosilicate. The temperature and reaction time has a great influence on the descaling effect. Raising the temperature and prolonging the reaction time can obtain good effect.

Abstract: Soot, a crucial component of PM_2.5 in the ambient air, is a prime product of incomplete combustion of fule. The present paper uses a series of models, including nucleation of soot precursors, surface growth of soot particles as well as particles coagulation, to do numerical simulation of soot particles formation mechanism over time in combustion flame, with the aid of MATLAB platform by C language. Simulation results indicate that the concentration distribution of soot precursors like polycyclic aromatic hydrocarbons (PAHs) have direct effect on the concentration distribution of soot nuclei. Mass addition rate on soot particles surface rises over time since the enlargement of the surface area. In coagulation process, the number of small diameter particles decreases, while that of large diameter particles increases.

Abstract: In the process of polymer flooding in porous media, polymer was detained because of interactions between surface adsorption and polymer molecules, and this could lead to negative effects on oil displacement. For polymer static adsorption in Xinjiang conglomerate reservoir, both of the HPLC analysis and Langmuir isothermal method were adopted to study on the rules. Results have showed that the adsorption process could be divided into 3 stages: rapid growth, slow growth and stable state. The adsorption of polymer KA on oil sands is in line with the Langmuir isotherm law. The adsorption amount is different for polymer KA on four types of oil sands. For equilibrium adsorption, the maximum value is from argillaceous sandstone, followed by conglomeratic sandstone. The third is argillaceous gravel, and the minimum is sand gravel. Adsorption equation analysis is consistent with the experimental principle statement.

Abstract: The purpose of this study is to investigate the catalytic effects of different metals in Shengli lignite on the char reactivity. The pyrolysis of Shengli lignite and various metal catalyst loaded coal was investigated in a small fixed-bed reactor, and the gasification activity with steam for different chars was compared as well. The results show that Fe, Ni, Ca and K could effectively lowering the gasification temperature, enhancing the gasification reactivity of SL char. Alkali (K) and alkaline earth (Ca) could be feasibly used as catalysis for the catalytic steam gasification at relatively low temperatures (550~700°C) to produce gases with high H₂ (63.2~63.8 v%) and low CO (below 0.9%), and promoting the carbon-water reaction, the water-gas shift reaction to some extent.

Abstract: In the one compartment electrochemical cell equipped with platinum electrodes electrochemical fixation carbon dioxide was conducted under ambient conditions. Ionic liquid BMimBr is supporting electrolyte. The aimed product dimethyl carbonate was electrosynthesized in a dialkylimidazolium ionic liquids-propylene oxide-methanol system under normal temperature and pressure. The result indicated that the highest yield of 37.8 % was obtained in the condition of working temperature 30 °C, electrolytic voltage 5.5 V, the mass of CH₃OH 0.484 mol, propylene oxide 0.052 mol and bmimBr 0.059 mol.

Abstract: The exergy calculation model was established to evaluate the energy consumption and exergy assessment of a typical coal pyrolysis process system with a capacity of 1000 kg/h for raw lignite. The results indicate that although the drying unit consumes more energy, it is the pyrolysis unit that exist the maximum exergy loss because of great temperature gradient at the first reaction stage. In addition, the energy quality factor of fuel was defined to evaluate the pyrolysis yield grade. It is found the tar energy quality factor is higher than that of semi-coke and syngas. Besides, the waste steam from drying unit contains plenty of exergy, which could be used to preliminary heat raw lignite in order to reduce the energy consumption and exergy loss of drying unit.

Abstract: In CO₂ foam flooding progress, foams formed by CO₂ and surfactant solution can reduce the fluidity of CO₂, improve sweep efficiency and flow behavior of CO₂ in heterogeneous oil reservoir, prevent fingering and channeling and improve recovery efficiency. However, the study on the CO₂ foam flooding characteristics is still in the initial stage, this paper focused on experimental testing the CO₂ foam fluid flooding characteristics. Factors affecting the foam flooding efficiency, such as surfactant concentration, foam quality, injection method and core permeability, were studied in more detail in the paper, and influencing laws of factors on flooding efficiency and recovery efficiency were analyzed, moreover, based on experiments, the optimum foam quality and injection method, which have a practical and theoretical significance to the engineering application, were obtained.

Abstract: Soot is produced in incomplete combustion of fuels, it is harmful to human health and the environment. Sampling points were set along the flame height of different air-fuel ratios in ethylene/air IDF and samples were tested by transmission electron microscopy (TEM). MATLAB software was used to process TEM images, calculated the fractal dimensions of soot samples and analyzed the fractal features. With the increasing of air-fuel ratio, the soot fractal dimension decreases, the size and the number of primary particles included in aggregates increase. With the increasing of flame height, the fractal dimension value decreases, and the size of primary particle increases, the aggregating soot particles are united loose.

Abstract: The steam gasification experiment of FJC lignite, BL lignite, SH bituminous and TT anthracite were carried out by using an own design WFSM-3060TL Catalyst Evaluation Unit apparatus. The infulence of coal rank on the steam gasification activity was investigated. Experiment conditions: heating rate:15°C/min (25°C-500°C), 2°C/min (500°C-850°C). The resuts show that gasification of lignite is better. With the deepening of coal rank, the steam gasifiction reactivity of coal samples decreases obviously, the higher the coal rank is, the worse the gasification reactivity is.