Characterization of Palm Biodiesel Deposit on The Locomotive Engine Fuel Filters: Composition, Physical, Chemical Properties

Title: Characterization of Palm Biodiesel Deposit on The Locomotive Engine Fuel Filters: Composition, Physical, Chemical Properties

Authors
Authors and Affiliations

Ihwan Haryono, Muhammad Ma'ruf, Hari Setiapraja, Rizqon Fajar , Dieni Mansur

Corresponding email: ihwan.haryono@brin.go.id

Published at : 24 Dec 2024
Volume : IJtech Vol 15, No 6 (2024)
DOI : https://doi.org/10.14716/ijtech.v15i6.5781

Cite this article as:
Haryono, I., Ma'ruf, M., Setiapraja, H., Fajar, R., Mansur, D., 2024. Characterization of Palm Biodiesel Deposit on The Locomotive Engine Fuel Filters: Composition, Physical, Chemical Properties . International Journal of Technology. Volume 15(6), pp. 1873-1885

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Ihwan Haryono	Research Center for Energy Conversion and Conservation, National Research and Innovation Agency, KST B.J Habibie Serpong, South Tangerang, Banten 15310-Indonesia
Muhammad Ma'ruf	Research Center for Energy Conversion and Conservation, National Research and Innovation Agency, KST B.J Habibie Serpong, South Tangerang, Banten 15310-Indonesia
Hari Setiapraja	Research Center for Energy Conversion and Conservation, National Research and Innovation Agency, KST B.J Habibie Serpong, South Tangerang, Banten 15310-Indonesia
Rizqon Fajar	Research Center for Transportation Technology, National Research and Innovation Agency, KST B.J Habibie Serpong, South Tangerang, Banten 15310-Indonesia
Dieni Mansur	Research Center for Chemistry, National Research and Innovation Agency, KST B.J Habibie Serpong, South Tangerang, Banten 15310-Indonesia

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Abstract

Characterization of Palm Biodiesel Deposit on The Locomotive Engine Fuel Filters: Composition, Physical, Chemical Properties

High ratio biodiesel blend fuel has become mandatory for all sectors including road and non-road vehicles since 2016. All stakeholders of biofuel in Indonesia had conducted a specified investigation through road tests 40,000 km to evaluate the high biodiesel effect on performance, emissions, and engine components. An improvement in fuel properties of biodiesel FAME has also been stated in the new fuel standard. Moreover, the recommendation for proper high biodiesel ratio handling and storage also socialized to all stakeholders. However, shorter fuel filter mileage and fuel degradation for long storing still remain issues for the implementation of biodiesel in Indonesia. An assessment of biodiesel in a locomotive in Indonesia was conducted through a rail test conducted for 6 months with a coal train in Sumatera Island with a blend ratio of 20% by volume (B20) and pure diesel fuel (B0) as a reference. The purpose of this rail test was to investigate the effect of B20 on various factors at railway application. This paper is presented a detailed analysis of the deposits formed in the used main and used twin filters of the locomotive for one maintenance period. An analysis of morphology, elemental analysis, and its physical and chemical properties was done by using a digital microscope, thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), and gas chromatography-mass spectrometry (GC-MS), respectively. An analysis showed that B20 had more deposits on the main filter compared with B0, while it had fewer deposits on the twin filter. Deposit in both of main and twin filters for B20 was identified mostly from hydrocarbons and fatty acid methyl esters. Analysis results also recommended that the fuel filter mileage of B20 was still possible to be prolonged with the current fuel filter standard by considering to deposit formation for both B0 and B20 still under tolerance level.

Keywords

B20; FAME; Fuel filter; Locomotive; Palm biodiesel

Introduction

Biodiesel is a promising alternative fuel to support the implementation of sustainable fuels and reduction of exhaust gas emissions from transportation sector in Indonesia (Wirawan et al., 2024; Tjahjono et al., 2021). Several improvements have been applied to the automotive sector, including the specified development of a fuel system for biodiesel, appropriate handling and storage of biodiesel, and limitations on the amount of water and mono-glycerides permitted biodiesel. Those improvements are required to meet specified engine performance and emission from various biodiesel production processes and feedstock resources (Zhang et al., 2022; Said et al., 2018; Susila, Rachimoellah, and Sutantra, 2011). Many studies have reported the effects of using biodiesel fuel in automotive applications with various engine technologies and biodiesel resources (Lee and Cho, 2024; Reksowardojo et al., 2023; Mokhtar et al., 2023; Pandey, Mishra, and Verma, 2022; Kumbhar et al., 2021). Nevertheless, a few studies have reported the utilization of high-ratio biodiesel with a blending volume above 10% in the locomotive applications. An implementation of biodiesel on a locomotive had similar results to automotive, which could raise an issue in the intake system and fuel filter clogging (Stead et al., 2019). Skinner et al. (2007) reported that the utilization of biodiesel could decrease fuel filter mileage and reduce fuel economy. At the same time, it has an advantage on low exhaust gas emission except for NOx without any significant reduction in engine power. Utilization of high-ratio biodiesel fuels could also affect to accelerate the replacement time of fuel filters due to their faster deposit formation (Heck, Mohammad, and Abi-Akar, n.d.; Komariah et al., 2018; Graver, Frey, and Hu, 2016; Ge et al., 2009).

Deposit in the engine could be in various forms, including carbonaceous, polymeric, carboxylate salts, and inorganic salts. Further, a typical deposit in an engine fuelled with biodiesel was a sticky deposit due to its saturated fatty acid contents. High temperature and pressure of the advanced injection system would lead to building deposits at the injector due to cavitation in the injector and fuel thermal stress. While storage sediment, biodiesel, lubricant adulteration, metal catalyst, water as well as bio-contaminant were also the sources of deposit for both in injector and fuel filter (Barker et al., 2020). Deposit formation in the injector formed due to hydrocarbon decomposition and condensation as a result of the unburn product of low volatility, high viscosity, and density of biodiesel. Carbonaceous deposits could occur in injectors at a temperature higher than 350°C (Hoang, Le, and Pham, 2020; Hoang and Le, 2019). Deposit formation in biodiesel fuel is also affected by its long chains, low ignition point, and high boiling point, resulting in a higher maximum evaporation rate point (MEP) compared to diesel fuel (Suryantoro et al., 2016). Moreover, Hoang also reported that the degradation of lubricating oil would also influence deposit formation in the combustion chamber (Hoang and Pham, 2018). While the deposit in the fuel filter was in a sticky form which was mainly influenced by biodiesel contaminants such as monoglyceride, water, and metal content which occur at a temperature below its pour point. These types of deposits would be easily removed as the temperature increase. However, if there is some solid deposit from diesel fuel accumulated in the void space of the fuel filter, then it is mixed with a sticky deposit of biodiesel then, which would result in fuel filter clogging (Paryanto et al., 2022). Csontos et al. (2020; 2019) evaluated deposit characteristics by using Gas Chromatography-Mass Spectrometry (GC-MS), X-ray Fluorescence Spectroscopy-Energy Dispersive X-ray Spectrometry (XRF-EDX), Fourier-Transform Infrared Spectroscopy (FTIR), and Thermogravimetric (TGA). They identified that carboxylic acid (CA) and unreacted CA, oxidized polymer compounds, glycerol, sterol, other impurities, and contaminants could be from biodiesel degradation and its production process (Csontos et al., 2020; 2019). Meanwhile, Barker et al. (2009) have reported that carbon with C₁₆-C₁₈ was the main component of the injector deposit (Barker et al., 2009). However, some studies also have reported that the utilization of biodiesel fuel would not have a significant difference in fuel filter mileage compared with pure fossil diesel fuel (Petiteaux and Monsallier, 2019; Nelson, 2012). Lammert, Barnitt, and McCormick (2009) have recognized unsuitable cold flow properties of biodiesel for implementation in low-temperature conditions during the winter season.

In a previous study, a used fuel filter of B20 from one period of fuel filter changing was analyzed with uncontrolled properties of B20, locomotives, and trips. It found that the B20 fuel filter had shorter mileage (Ma’ruf and Haryono, 2020). Furthermore, an evaluation with rail test B20 was conducted on a coal train in Sumatera Island to evaluate the effect of B20 on the locomotive in the more controllable testing environment, including fuel, locomotive, and trip. Specified locomotives with controlled B20 properties were prepared for this evaluation during its six months rail test. This paper reports specifically on the characteristic of a used fuel filter diesel locomotive for 3 months fuelled with B20 and pure diesel fuel. This rail test has been used as a reference to improve the biodiesel production process, the application of proper handling and storing of B20, and the development of engine components, especially fuel filters. Thus, the target for a longer lifetime of biodiesel fuel filters with high concentrations can be achieved with the use of diesel oil (B0).

Experimental Methods

Deposit formation in fuel filters is influenced by fuel impurities and contaminants and fuel flow rate. In this rail test, fuel properties were controlled with specified fuel sources, handling, and storing. Periodic sampling and analyzing of tested fuel were conducted during the rail test to ensure the fuel properties meet the requirements stated by the Directorate General of Oil and Gas of Indonesia. However, a contaminant from the surrounding environment during the rail test, such as coal dust, could not be controlled. Here, the period analysis of tested fuels showed a deviation of less than 5%. The fuel flow rate, which is indicated by the mode of operation of the locomotive, was controlled by a constant trip with the same locomotive. Here, the trainload represented by carried coal could not also be set in the same amount for each trip. Nevertheless, the trainload for every trip was recorded to analyze the deviation of load. Furthermore, a source of error could also be possible during the sampling process, preparation, and analysis of the samples.

2.1. Materials

A rail test was conducted using two types of fuels: a biodiesel blend with a ratio of 20% by volume (B20) and industrial diesel fuel available in the Indonesian market (B0). Table 1 shows the fuel properties for both B0 and B20. In this study, the fuel properties shown in Table 1 were tested using the specified ASTM methods, except for oxidation stability, which was measured according to EN 15751 standard. B20 exhibited better properties in terms of cetane number, density, flash point, sulfur content, distillation, and lubricity compared to B0, as shown in Table 1. However, B20 had some disadvantages, such as higher water content and monoglyceride levels, which could lead to deposit formation in the fuel filter.

Table 1 Detailed Properties of B0 and B20 Fuel Sample

2. Testing Methods and Analysis

An analysis of the deposit and its contents of the fuel filter was done for the used main and twin filters of the coal train fuelled with B20 and B0. Two trains were run at the same time for 6 months, and periodic maintenance was at 3 months. Here, the sampling of used fuel filterss was at fuel filter changing on 3 months based on a recommendation from the locomotive manufacturer. In this study, used main and twin filter deposits were identified for their morphology, elemental analysis, and chemical and physical analysis by using a Hirox microscope with type KH-8700, thermogravimetric (TGA) with differential thermogravimetric (DTG), gas chromatography-mass spectrometry (GC-MS) type 6890 and Fourier-transform infrared spectroscopy (FTIR) Shimadzu–IR Prestige 21, respectively. Here, a filter size of 1 cm²was soaked in 10ml of acetone, chloroform dichloromethane (DCM), and n-hexane as organic solvents before GC-MS analysis. The purposes of using various solvents were to evaluate and determine the effectivity of solvent on dissolving precipitate. A Whatman microfiber filter paper with a diameter of 47 mm and pore of 0.7 µm was utilized to filter precipitate matter in solvent to avoid small solid particles entering the GC-MS column.

2.3. Diesel Locomotive Coal Train

A rail test was conducted with a locomotive from Electro-Motive Diesel (EMD) Model GT 38 AC. The locomotive has three stages of fuel filtration, including a strainer, main filter, and twin filter. A strainer is installed to filter contaminants with sizes >10 microns and water. While the main filter and twin filter was intended to filter particle with a size of 5-10 micron and 3-4 microns, respectively. Figure 1 shows the fuel filtration system for the EMD locomotive for both fuelled with B20 and B0.

Figure 1 Schematic diagram of fuel system in EMD locomotive

Results and Discussion

Morphology and deposit content was evaluated on the main and twin fuel filter of the locomotive fueled with B20 after 3 months of use. Further, an evaluation of the fuel filter with B0 fuel had also been done with B0 as a reference condition. Here, deposit evaluation on the strainer was not conducted due to fewer deposits found as it just filtered coarse bulk particles such as rocks or gavel for both locomotives with B20 and B0.

3.1. Morphology and Thickness of Deposit

Figure 2 shows an evaluation of morphology and thickness of deposit on used main filters with B20 and B0 fuel after 3 months by using a 3D digital microscope at a magnification of 500 times and 100 times, respectively. The used main filter for B20 was fully covered by deposit so that the fuel fiber could not be recognized, while the fiber and pores of the used main filter with B0 were still clearly observable. An evaluation of deposit thickness on the used main filter showed that B20 was higher compared with B0, with an average of 822 µm and 699 µm, respectively. Moreover, it is found that the deposit characteristic of B20 was soft so that B20 was still possible to flow through the used main filter with less resistance. A measurement of differential pressure also showed that the pressure difference between the upstream and downstream of the filter did not change significantly. Therefore, it could be the reason for similar power of locomotive after 3 months with B20 (EBTKE, 2018).

Figure 2 Main filter condition after 3 months of usage: (a) B0; and (b) B20

Visual inspection of deposit on the used twin filter showed that fibers were still clearly visible for both B20 and B0 as shown in Figure 3. However, the granule deposit size of B20 was bigger compared with B0, which covers the used twin filter surface uniformly. Figure 3 also shows the thickness of the deposit at the used twin filter fueled with B20 and B0. Measurement results showed that B20 and B0 had an average thickness of 601 µm and 621 µm, respectively, as shown in Figure 3. The lower deposit thickness of B20 compared with B0 could be considered due to most of the contaminants B20 was filtered on the main filter resulted in less filtered deposit in twin filters. Blend fuel of FAME biodiesel is characterized by solid-formed deposit and the wet flexible waxy precipitate, which resulted from impurities of diesel fuel and FAME. Moreover, contaminants of blend fuel could also be from thermal oxidation and metal-catalyzed oxidation of high-temperature recirculation fuel. In our previous investigation on used locomotive fuel filters, we identified some elements contained in the deposit of the used filters, either organics or un-organics. An analysis of three samples of a used locomotive, water separator, and generator fuel filter has found metal elements such as Al, Si, S, and Ca. An accumulated combination of those solid and wet waxy deposits would result in suddenly blocked fuel filter (Paryanto et al., 2022; Ma’ruf and Haryono, 2020; Wadumesthrige et al., 2010).

Morphology and thickness measurement on the same pores at the main and twin filter result showed that the filtering efficiency of B20 is better than B0. The difference in result with the previous study could be considered due to its better properties, handling, and storing of B20 during rail test. Here, a suppression of deposit in fuel filter could be achieved in a more significant result by controlling an amount of monoglyceride content at a maximum of 0.4%, as an amount above this number is still expected to form deposit (Cardeno et al., 2020). Therefore, an evaluation of the proper pore size diameter of high-ratio biodiesel would be required to achieve effective filtration. Fuel filter pore diameter also can determine fuel filter mileage based on targeted contaminants of high biodiesel blends.

Figure 3 Twin filter condition after used for 3 months: (a) B0; and (b) B20

3.2. Physical and chemical properties of the filter

To identify the chemical functional groups captured on the filter, an analysis of the filter used with B20 fuel was performed using FTIR. Csontos et al. (2019) also utilized this method in their work. However, since FTIR can also detect the functional groups of the filter material itself, a new filter was used as a comparison. The FTIR analysis spectrum is presented in Figure 4, and Table 2 shows the predicted functional groups for each peak.

Figure 4 Spectrum FTIR of B20 fuel

Based on the spectrum of FTIR, as shown in Figure 4, the peaks on a new filter generally also appeared on the used filter. However, several new peaks appeared on the used filter, such as at wave numbers 1259 and 1232 cm^-1, which were the C-O-C group of ester, probably derived from biodiesel. Furthermore, wave numbers of 626 and 468 cm¹ were the naphthalene group, and 609 cm^-1 was SO₂ group derived from petrodiesel fuel.

Table 2 Chemical functional groups in the filter based on FTIR analysis

The filtered impurities after using B20 fuel originated from biodiesel and petrodiesel. One of the efforts to improve the quality of biodiesel blends can be done by reducing the content of impurities in B0, which implies minimizing the interaction in the biodiesel blend. The used filter was also analyzed by Thermogravimetric (TG) analysis to understand its thermal properties compared with the new filter. TG analysis was conducted at N₂ conditions with a heating rate of 10°C /min from room temperature to 600°C. Figure 5 shows TG or weight loss and derivative thermogravimetry (DTG) curves of the filters.

Figure 5 showed that thermal degradation of the used filter containing deposits vaporized at three different regions of 35 - 150°C, 150 - 320°C, and 320 - 400°C with peak temperatures around 80°C, 250°C, and 330°C. The peak temperature at 250°C could correspond with TGA results conducted by ELTahry et al. (2022) that peak temperatures of vaporized deposits in the form of glycerol, sterol glucosides (SGs), and metal carboxylates at around 250°C, 350°C, and 480°C, respectively. At region 35 – 150°C was attributed to water evaporation and volatile compounds in the filter material. Besides glycerol (ELTahry et al., 2022), at region 150 – 320°C hydrocarbons with carbon atoms [C] ranging from C13 - C18, such as Tridecane, Tetradecane, Pentadecane, Hexadecane, Tridecane, and Octadecane were decomposed because the used filter was analyzed as received. Moreover, in the region at 320 – 400°C, there was decomposition or evaporation of larger carbon atoms [C] ranging from C19 - C27, such as Nonadecane, Eicosane, Heneicosane, Docosane, Tricosane, Heptacosane, Tetracosane, Pentacosane, and Eicosane based on GCMS analysis as shown in Figs. 6-7. While the new filter only consisted of two regions of 35 – 150°C and 250 – 400°C. At 250 - 400°C, decomposition of the larger molecular weight material, such as polymer or composite, occurred in the new filter. Decomposition of the filter material also occurred in the used filter that was incorporated with the deposited material.