Studies on Tribo-Corrosive Behavior of Various Biodiesel to Optimize Its Blend with Diesel for CI Engine Applications

Abstract

The present study focuses on identifying the optimum diesel- dual biodiesel blend from the available eight biodiesel. TOPSIS and PROMETHEE methods based on multiple criteria decision-making techniques are selected to identify the best dual biodiesel-diesel blend. The engine performance, combustion and emission are chosen as criteria for the decision making. The brake-specific fuel consumption and thermal efficiency are the key parameters to determine engine performance. Similarly, the peak in-cylinder pressure and the delay period characterize combustion, while the emission is defined by the emissions measured for Nitrogen oxide (ppm), Hydrocarbon (ppm), Smoke opacity (%). The entire study is carried out in two steps to minimize the experiments. The implementation of two different decision-making methods with various parameters guarantees that the solution is similar to the ideal solution. The70D15CA15R (70% Diesel, 15% Castor and 15% Rapeseed) is obtained as an optimum blending reference to all engine performance. The second part of the study focuses on identifying the optimum percentage of water to be added for preparing a stable emulsified fuel blend and the possibility of reducing engine emission (NOx and HC) using 70D15CA15R as the base fuel. This optimum blend has been used for the preparation of W/O emulsified fuel. In emulsified fuel, water percentages varied from 1 to 5%, 10%, and different emulsified fuel blends were prepared based on HLB ratios ranging from 4.3, 5 and 6. The results of the first and second phases of the experiments show that the addition of 5 v/v % water seems to be a more stable blend than the addition of 1, 2, 3,4 and 10 v/v % water. The experiments were carried out on a VCR, single-cylinder, four-stroke, water-cooled diesel engine operated under varying load conditions 0 to 110% at constant operating speed (1500 rpm) with injection time 20° BTDC. Based upon the engine performance, combustion, and emission analysis, the best optimum emulsified fuel has been selected. From the results, emulsified fuel having 5% water concentration, HLB: 6 and 2% Surfactant was found to be the optimum emulsified blend. The third part of the study focuses on identifying the corrosion behavior of biodiesel, optimum blend and emulsified fuel blend prepared from the available eight biodiesels. Gas chromatography-mass spectrometry (GC-MS) was performed on eight biodiesels and a hypothesis was proposed to predict the corrosion behavior. To corroborate the hypothesis, a static immersion tests, Scanning Electron Microscope (SEM) and surface roughness analysis were conducted. The immersion test was conducted for 150 days at ambient temperature conditions, later on the corrosion rate of metals was examined. Results indicate that the bronze has a maximum corrosion rate of 0.0674 mph with Karanja biodiesel followed by palm biodiesel. The Karanja biodiesel has the highest susceptibility to corrosion with all metals, while the diesel is found to be the lowest with intermediate values for rapeseed and castor. The optimum blend 70D15CA15R and emulsified fuel W5S2HLB6 showed best-compromised results amongst all the biodiesel investigated in the present study. The fourth part of the study focuses on identifying biodiesels' tribological behavior (Jatropha, Castor, Neem, Linseed, Karanja, Rapeseed, Palm & Canola), optimum blend and emulsified fuel blend on five different metals (Aluminum, Brass, Bronze, Copper and Iron). Tribology test has been examined under constant hydrodynamic lubrication condition at room temperature on 40 N load with a 10000 m sliding distance and 5.5 m/s tip velocity for every experiment on the pin on disc tribemate. During the test coefficient of friction, steady-state coefficient of friction, wear volume loss, wear rate, weight loss, microscopic surface analysis of test metals was investigated. Chemical composition and functional groups of test fuels was analyzed by FT-IR. As the sliding distance increases, wear rate, weight and volume loss of metals were found highest with Neem and Castor biodiesel. The lowest wear, metal weight and volume loss was observed with Jatropha, Palm and Canola biodiesel. As diesel's volatility is higher compared to biodiesel and also due to high friction force between pin & disc, it is not safer to use diesel for wet lubrication test in a pin on disc apparatus. A long run endurance test as per IS 10000-part V and IX was performed on CI engine fueled with diesel to overcome this problem. It has been observed that the wear, surface roughness, and carbon deposition on metal parts' surface was found too higher and denser. A recreation model was also proposed for predicting the wear rate. The predicted wear results, in terms of weight loss, are close to the actual weight loss of various components this indicating the robustness of the model. Keywords: Fuel optimization, Dual biodiesel diesel blend, MCDM, PROMETHEE, TOPSIS, Biodiesel, Corrosion rate, Surface roughness analysis, SEM image analysis, GC-MS, Tribology, Wear, Pin-On-Disc, Lubrication, Wet-test, CoF. C.I Engine, Alternate Fuel, Engine Performance, Emission analysis, Emulsification.