The need for electricity in Indonesia continues to increase along with the pace of economic development and its population. One of the power plants that continues to be developed in Indonesia to meet the increasing electricity demand is the Steam Power Plant (PLTU) because this PLTU produces electricity with a large capacity considering the high electricity demand in Indonesia.
This was conveyed by Yulinda Lestari at an open doctoral promotion session held at the Smart Meeting Room FTUI (13/11). The Metallurgical and Materials Engineering doctoral student presented her research dissertation related to the Manufacture of Ceramic Composite Anti-Fouling Layer Based on Local Mineral Resources.
“In the Java-Bali system, the candidate plants considered for the development plan are the 1,000 MW class ultra-supercritical and 600 MW supercritical coal-fired power plants. For the Java-Bali electricity system, PLN has planned a 1,000 MW class coal-fired power plant with ultra-supercritical technology to obtain better efficiency and lower CO2 emissions,” Yulinda explained in her presentation.
This ultra-supercritical technology where steam conditions reach 760°C, 35 Mpa has been able to reduce CO2 emissions by 25%. The main difference between supercritical and ultra-supercritical is the temperature of the steam produced by the boiler, which reaches 600°C with a pressure of 240-300 bar and can increase efficiency by at least 8%.
Coal-fired power plants are designed to carry a base load in line with the relatively low price of coal compared to other fossil fuels. Coal combustion in addition to producing carbon dioxide emissions that cause global warming effects, also causes slagging and fouling which is the phenomenon of sticking and accumulating melted coal ash on heat exchanger tubes or boiler walls.
This slagging and fouling problem is very serious because it can have a major impact on boiler operations, such as heat delivery problems, decreased boiler efficiency, pipe blockage, and pipe damage due to clinker detachment. These problems will shorten the life of the boiler as well as other components in the power plant, resulting in economic losses. Other mechanisms that cause boiler damage are creep rupture, fatigue, fireside corrosion, steam side erosion and oxidation, due to high operating conditions.
“One of the solutions used to overcome the problem of boiler damage is the coating of metal materials commonly used for power plants with ceramic composite coatings that are high temperature resistant and anti-fouling. Coating refers to a process that involves applying a layer of material made from a liquid or powder solidification process over a metal surface. This coating adheres continuously to the metal surface, minimising the metal’s contact with its environment,” explains Yulinda.
Composite coatings offer a solution to this limitation by combining the desirable properties of several different materials, such as resistance to extreme conditions, hardness, toughness, and chemical resistance, into a single coating. This composite coating material was chosen to be based on ceramic materials because ceramic coatings have been widely used to improve the properties of metals. Ceramic coatings are needed in the industrial world for various applications, therefore the coating requirements and specifications also vary and are tailored to the application.
In this study, Yulinda used the main raw material for coatings in this study derived from local mineral materials, namely Kalimantan Zircon sand. Zircon sand contains lubricants that are anti-fouling, high temperature resistant and have good chemical stability.
“The material used for the coating mixture is Zirconia that has been purified from Kalimantan Zircon sand. The purification of Zirconia uses the alkaline fusion process method which produces quite high purity with a simpler process. Zirconia is easily stabilised by other metal oxides to change physical, mechanical and chemical properties,” Yulinda continued.
The Dean of FTUI, Prof. Dr Heri Hermansyah, S.T., M.Eng., IPU, appreciated Yulinda’s innovation as a progressive step in improving the operational efficiency of power plants, especially those that use coal as an energy source. “This research involvement not only provides technical solutions to boiler problems but can also have a positive impact on the Indonesian electricity world as a whole. By utilising local resources such as Kalimantan zircon sand, this research not only creates innovative solutions but also supports the development of energy independence and security in the country’s electricity sector.”
Yulinda Lestari earned her doctorate with a GPA of 3.98 and was recorded as the 61st doctoral graduate of the Department of Metallurgical and Materials Engineering and the 520th of the Faculty of Engineering, University of Indonesia. The promotion session was chaired by Prof. Dr. Ir. Yanuar, M.Eng., M.Sc. with promoter Prof. Dr. Ir. Anne Zulfia Syahrial, M.Sc. and co-promoter Prof. Dr. Ir. Johny Wahyuadi Soedarsono, DEA. The examination team consisted of Prof. Dr. Ir. Akhmad Herman Yuwono, M.Phil.Eng.; Prof. Dr. Efendi Mabruri; Prof. Dr. Ir. Dedi Priadi, DEA.; Prof. Dr. Ir. Rini Riastuti, MSc; and Dr. Ir. Sotya Astutiningsih, M.Eng.
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