دانلود رایگان مقاله انگلیسی آزمایش خوردگی فلزات در تماس با کلسیم کلرید هگزا هیدرات مورد استفاده در ذخیره انرژی حرارتی - وایلی 2017

عنوان فارسی
آزمایش خوردگی فلزات در تماس با کلسیم کلرید هگزا هیدرات مورد استفاده در ذخیره انرژی حرارتی
عنوان انگلیسی
Corrosion testing of metals in contact with calcium chloride hexahydrate used for thermal energy storage
صفحات مقاله فارسی
0
صفحات مقاله انگلیسی
11
سال انتشار
2017
نشریه
وایلی - Wiley
فرمت مقاله انگلیسی
PDF
کد محصول
E7506
رشته های مرتبط با این مقاله
مهندسی مواد، شیمی
گرایش های مرتبط با این مقاله
خوردگی و پوشش و حفاظت سطح مهندسی
مجله
مواد و خوردگی - Materials and Corrosion
دانشگاه
Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education - School of Energy and Environment - Southeast University - P. R. China
کلمات کلیدی
خازن های هوا سرد، کلسیم کلراید هگزاهیدرات ، خوردگی، مواد تغییر فاز، ذخیره سازی انرژی حرارتی
چکیده

Thermal energy storage (TES) using a phase change material (PCM) has been proposed as a supplemental cooling system to improve the performance of power plant air-cooled condensers (ACCs). In this proposed system, frozen PCM would remove heat from plant’s condensing steam during the day, which would melt the PCM. The PCM would be frozen at night as its stored heat is rejected to the cooler atmosphere. Calcium chloride hexahydrate (CaCl2 · 6H2O) is an attractive material to serve as a PCM in this innovative system due to its appropriate melting temperature, low price, and relatively high latent heat of fusion. The corrosion of container materials is a major challenge in using CaCl2 · 6H2O. Any material used needs to survive constant exposure to the salt for several years to ensure a long operational life for the system. In this study, the corrosion behavior of four metals in contact with CaCl2 · 6H2O was experimentally investigated. Three different temperature conditions and two pH level conditions were considered under static metal exposure conditions.

نتیجه گیری

4 | CONCLUSIONS


CaCl2 · 6H2O is a promising PCM for low temperature heat storage, which can be utilized in improving the efficiency of air-cooled power plants. For this hydrated salt to be used, any container (encapsulation material) used to contain it must resist corrosion by the salt throughout the system’s life. Long-term corrosion tests of CaCl2 · 6H2O in contact with four common metals (copper, low carbon steel, Al 5086, and Al 6061) were performed. The corrosion tests were carried out for four test periods (2, 4, 8, and 16 weeks), and three temperature conditions (30, 50, and 80 °C). The important findings of these tests are as follows:


(1) Effect of time on corrosion rate. For all temperature conditions, the corrosion rates of carbon steel, Al 5086, and Al 6061, were found to decrease as test time increased. This was expected as it is well known that corrosion rates begin to slow down as a protective oxide layer forms on the surface of the metal. Interestingly, copper did not follow this trend, with the corrosion rate of copper increasing with time for the 80 °C temperature condition.


(2) Effect of temperature on corrosion rate. While temperature is known to accelerate corrosion in many situations, its impact on the corrosion rate of metals immersed in CaCl2 · 6H2O has not been reported in the literature. Testing of the four metals at 30, 50, and 80 °C confirmed the hypothesis that an increase in temperature results in an increase in the corrosion rate for each of the metals. Plotting the natural log of the corrosion rate versus 1/T, these test results were shown to follow an Arrhenius relationship, with apparent activation energies for the corrosion reactions being found.


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