Advanced Materials Research Vols. 516-517

Abstract: Three transfers have been discussed with analysis-simplified and extension. Some experimental data have been used to regress the main parameters of processes.

Abstract: _{Subscript text}The kinetic model for simulating the mechanism of the promoted effect of methanol on the NOxOUT process has been established and it mainly includes the optimal sub-mechanisms respectively for the NOxOUT process and the chemical reaction of methanol. The oxygen concentration does not obviously influence the maximum NO reduction efficiency in the range of 1-6 %, but the temperature window is overall shifted to lower temperature zone with oxygen concentration increased. Meanwhile, the mole ratio of urea to nitric oxide by a factor of 2 should be maintained between 1.5 and 2 from both the efficiency and running cost view. Also, ample residence time of 300/T-400/T s must be guaranteed for the reduction occurring thoroughly. Methanol does not compromise the maximum NO reduction efficiency and broadens the temperature window towards low temperature zone. The promoted mechanism of methanol on the NO_xOUT process is the abundant OH formation through the methanol regenerative reaction of CH₂OH/CH₃O+H2O=CH₃OH+OH and methanol should be maintained at 50-100 ppm for an obvious promoted effect. During the co-injection of methanol and urea, the “ammonia slip” is depressed, especially at 1173 K where the promoted effect on NO reduction is obvious, but emission of nitrous oxide is also markedly increased at this temperature.

Abstract: Based on kind of medium-sized ground source heat pump incubator condenser’s design and research, incubator can get good uniformity temperature filed. Incubation experiments showed that the incubator reached the national key performance indicators. Compared with the traditional way of heating incubation, the experiment got a high rate of hatchability and child health. Energy saving effect is remarkable and achieve good social and economic benefits.

Abstract: In this work, a return mapping algorithm is utilized to implement the model into a finite element program and then Microplane theory is employed. A numerical procedure is also developed to implement the model as a user material subroutine for ABAQUS-Standard commercial code. Uniaxial tension test under a constant axial stress is simulated in order to study the behavior of shape memory alloys. A very good agreement is seen between the results obtained by the two approaches indicating the capability of microplane theory.

Abstract: In order to minimize the recirculation to ensure normal operation of the air-cooled condensers (ACC) system, the recirculation phenomenon and its dependence on ambient winds are numerically simulated by using the computational fluid dynamics code, FLUENT. Under the constant ambient temperature, the effects of different wind speed and wind direction on the recirculation are qualitatively considered by applying the concept of the recirculation rate. The mechanism of occurrence of recirculation are presented and analyzed. It was found that when considering about the existing and normally operating power plants, the recirculation is more sensitive to wind direction and wind speed. Based on the above results, three improved measures increasing the wind-wall height and accelerating the rotational speed of the fans near the edge of the ACC platform and lengthen or widen the platform are developed to effectively reduce the recirculation.

Abstract: In this paper, numerical simulation on thawing of frozen coal in tram of coke-oven plant was carried out. Simplified physical and mathematical models were developed and calculated, based on which the rules of coal thawing were obtained. By analyzing effects of wind temperature and wind speed on thawing, thawing time of frozen coal under different conditions was calculated, which can provide reference for accurate design and actual operating.

Abstract: In this paper, an iterative procedure was performed for the prediction of scale growth in T22 superheater and reheater tubes, which utilized empirical formulae for oxide-growth kinetics in steam and heat transfer analysis. Several expressions for oxide-growth kinetics and different thermal conductivities of scale were considered in calculations. The results indicate that the expression for oxide-growth kinetics can affect the estimated results significantly, and the thermal conductivity of scale has relatively small influence on the prediction of scale growth, but the influence degree increases with time.

Abstract: The previous research on adaptive neuro-fuzzy inferential systems (ANFIS) presented an approach to estimating the average indoor temperature in the building environment. However, the restriction on robustness limited the energy efficiency and indoor comfort ratio. An accurate and robust prediction model is proposed in this paper. Comparing to the previous unphysical rules based ANFIS prediction model, the improvement of the physical rules based ANFIS prediction model will be presented and the reason of better performance of this new model will be discussed. Three performance measures are using in evaluating the proposed prediction model.

Abstract: In order to elucidate the possibility of removal of silicic acid from geothermal water, the calcium nitrate and sodium hydroxide as removing agent was investigated under various conditions. The initial concentration of silicic acid in geothermal water was 412 ppm as Si. The concentration of silicic acid decreased rapidly when the removing agent was added. Precipitation reaction for silicic acid reached equilibrium within 30 minutes and was independent of pH. The removing rate of silicic acid increased with increasing the pH of solution. The high concentration of silicic acid in geothermal water was perfectly removed by addition of calcium nitrate with molar ratio of Ca/Si over 2.1 at pH12. XRD pattern showed that the component of precipitation was calcium silicate hydrate Ca₂SiO₄・nH₂O (CSH).

Abstract: The finite element model of supercritical boiler water-wall has been established and the ANSYS10.0 was used to simulate cross-section temperature distribution. The simulation result shows that fin-point is the highest temperature on the whole water-wall cross-section. As the fins thickness changed, fin-point temperature has a optimal value；Basing on some 600MW supercritical boiler, it has an optimal value when the fins thickness ranged from 7mm to 9mm.