A Comparison of Corrosion Behavior of Copper and Its Alloy in Pongamia pinnata Oil at Different Conditions

Vegetable oils are promising substitutes for petrodiesel as they can be produced from numerous oil seed crops that can be cultivated anywhere and have high energy contents, exhibiting clean combustion behavior with zero CO2 emission and negligible SO2 generation. The impact of biofuel on the corrosion of various industrial metals is a challenge for using biofuel as automotive fuel. Fuel comes in contact with a wide variety of metallic materials under different temperatures, velocities, and loads thereby causing corrosion during storage and flow of fuel. Hence, the present investigation compares the corrosion rates of copper and brass in Pongamia pinnata oil (O100), 3% NaCl, and oil blend with NaCl (O99) obtained by static immersion test and using rotating cage. The corrosivity and conductivity of the test media are positively correlated. This study suggested that the corrosivity of copper is higher than brass in Pongamia pinnata oil (PO). 1. Introduction The rate of petroleum reserve discovery is declining while energy demand keeps increasing. The current expansion of the Indian economy has escalated petroleum demand, prices have surged, hurting the economies of poor and developing countries. In order to improve the economic status, the renewable, nontoxic biofuel comes with many advantages for the environment. Vegetable oils represent a ready, renewable, and clean energy source that has shown promise as a substitute to petroleum diesel for diesel engines. Edible oils like soybean, rapeseed, sunflower, and palm oil are being used for the production of biodiesel [1] and have a very high value and market demand as food product causing food shortages and price increase especially in developing countries [2]. To overcome this situation, researchers are looking for nonedible oil plants. Pongamia pinnata [3, 4], Jatropha curcas [5, 6], and other trees native to humid and subtropical environments can be grown on degraded and marginal land. Based on the biodiesel handling and guidelines report, copper, brass, bronze, lead, tin, and zinc are found to be corroded by biodiesel. Corrosive characteristics of biofuel are important for long-term durability of storage tanks and pipelines. Metal contaminants can trigger undesirable reactions leading to the instability and degradation of biofuel. Currently used indicators of corrosiveness, namely, copper strip corrosion and TAN value as prescribed by ASTM standards, are not effective enough [7]. Corrosive nature of biofuel under wide spectrum of compositional and operating variables should be investigated to obtain