Advanced Materials Research Vols. 860-863

Abstract: A new type of helical baffles heat exchanger is presented in this paper. Comparative study, through numerical simulation, was undertook between the new helical baffles heat exchanger and segmental baffle board heat exchanger in shell side flow and heat exchange characteristics. Fluid medium in the shell side is air. At the same velocity in the same flow conditions, pressure drop of helical baffles heat exchangers fell by an average of 26.8% compared with segmental baffle board heat exchangers, and the unit pressure drop of the heat transfer ratio of helical baffles heat exchanger increased by an average of 40.6%.

Abstract: Building the early-warning system of energy conservation can help enterprises to improve the energy information management, control energy consumption, forecast and analysis the enterprises overall energy trends;and provide the basis for enterprises to further find the potential problems, to explore the energy-saving potential sites and to formulate the scientific and effective energy-saving programs. The study is mainly from three aspects:the choice of the early-warning objects and the practice of the early-warning system. Based on the existed research, this article summarize the limitations of the domestic research. . In order to provide reference and inspiration for the follow-up study.

Abstract: This paper takes the conversion system of sulphuric acid plant made with the sulphur as research object, utilizes Aspen Plus process simulation software to carry out steady state process simulate for the conversion process, and obtains physical property data of all the process streams; utilizing Aspen Energy Analyzer software, that the minimum heat transfer temperature difference (ΔTmin) determined is 10 °C, the temperature-enthalpy composite curve and the pinch temperatures of hot and cold streams are got under the ΔTmin, the energy consumption of heating utilities reaches zero, and cooling utilities use 45 °C of desalted water. Simulating for heat exchange network with pinch technology and Simulating the matching design of heat exchange network with Aspen Energy Analyzer software, the heat exchange effect is basically as same as the heat exchange network in actual production.

Abstract: This paper takes the conversion system of sulphuric acid plant made with the sulphur as research object, utilizes Aspen Energy Analyzer software and pinch technology to improve and optimize for the current heat exchange network of conversion system. The heat exchange network optimized by Aspen software is under the premise of reaching the requirement of heat exchange, its heat transfer area, utilities and operating cost reaches the minimum, achieving energy saving, and it provides a new approach for the optimal design of heat exchange network.

Abstract: In this paper, the model of SCR after-treatment system is established by the software MATLAB and the control strategy for the system is studied also. Based on Eley-rideal mechanism, four major chemical reactions including the adsorption of ammonia, desorption of ammonia, selective catalytic reduction and oxidation of adsorbed ammonia are selected to study the SCR control strategy. Based on the energy conservation law, the equation calculating the temperature of the layered model is derived. Combined with the equations of chemical reaction process, a mathematical model of SCR catalytic converter is established. To achieve a high NO_X reduction efficiency of SCR system, the reasonable and efficacious control strategies for the micro-element models of SCR catalytic is simulated, which including the feedback control strategy based on the feed-forward controller and the PID control strategy.

Abstract: Creep tests for smooth specimens and notched specimens of T92 steel were carried out to study the effect of multiaxial stress state on creep rupture behaviors at 650°C. Creep rupture life was estimated by representative stress at multiaxial state of stress, the failure behavior of multiaxial creep was analyzed, and Kachanov creep damage formula was used to analyze the experimental data. The results show that the notch strengthens rupture life, multiaxial rupture behavior is controlled by mixed parameters, the creep ductility of the smooth and notched specimen decreases with rupture time, and damage factors of the smooth specimen and notched specimen are similar according to Kachanov formula.

Abstract: The process parameters and quality of resistance spot welding for DP980 dual phase steel were studied through the orthogonal experiment method, and the influence of welding current, welding time and electrode force on the strength of welding joint has been discussed. The results show that the welding current has the greatest influence on the quality of welding joint for DP980 dual phase steel, and it needs relatively lower welding current for the DP980 dual phase steel as it has high resistivity, and appropriate increasing of electrode force is a feasible way to avoid the defect of shrinkage and it improves the joint strength.

Abstract: Energy is the material foundation to promote social progress and of humans survival. A large number of energy consumption has brought serious environmental problems. After Global Climate Summit in Copenhagen, The attention to the green-house gas emissions of our country from the international community grows day by day. Developing green power is vigorously an important way to reduce the emissions of greenhouse gases. However, the cost of green power is so high compared with the traditional fossil energy that green power cannot be promoted only depending on market mechanism. So the mechanism that supports green power should be established. Firstly the implementation of green power of foreign countries (mainly the United States and European Union countries) is analyzed, and its content includes implementation mechanism, the market main body and duties, policy, motivation, supervision, etc. Then the development of domestic green power is described in detail, and a comparative analysis is presented between foreign and domestic implementation of green power in various aspects. Now in our country, the provinces developing green power better are Jiangsu, Zhejiang, Shanghai, Beijing and so on. There are enough green-power resources, potential users in these regions. And with the excitation of national policy, the regions develop green power actively, laying foundation of implementation of green-power mechanism. Shanghai is now the first city of our country that implements mechanism of green power. After the analysis of the present implementation of green power, the deficiency and areas in need of improvement are presented, combined with Shanghais present green-power implementation mechanism, as well as the original national green-power implementation mechanism. And some policy suggestion is put forward for the recent national green-power development in finance, taxation, incentive etc, which analyses and improves the designation of green-power implementation mechanism, including the payments balance and the research of incentive mechanism.

Abstract: SnO₂ coatings were supplied on the surface of 304 stainless steel (304SS) by a sol-gel process followed by hydrothermal treatments at different reaction temperature and time, respectively. The effects of hydrothermal temperature and time in pure water on the anticorrosion performances of the SnO₂ films in simulated proton exchange membrane fuel cells (PEMFC) environments were investigated by potentiodynamic polarization curves, open circuit potential-time curves and electrochemical impedance spectroscopy (EIS). It was found that the SnO₂ coated 304SS via the hydrothermal treatment showed a better corrosion resistance than the sample without hydrothermal treatment and bare 304SS. The SnO₂ coated 304SS hydrothermally treated at 160°C for 3h showed the highest corrosion resistance among the samples. The results have been discussed in terms of surface structure of SnO₂ film and its anticorrosion performance in simulated PEMFC environments.

Abstract: Due to the intensifying energy crisis, the fuel cell research gradually becomes a hot spot, because it is non-toxic, cleaning, inexpensive and easy to obtain. However, there are still many problems in DEFC research, such as cathode, anode catalyst, battery electrode preparation and others. This paper reviews the preparation methods of DEFC anode catalyst, including impregnation reduction method, microemulsion method, and the other methods.