IOSR Journal of Applied Chemistry (IOSR-JAC) e-ISSN: 2278-5736.Volume 12, Issue 1 Ser. I (January. 2019), PP 44-54 www.iosrjournals.org DOI: 10.9790/5736-1201014454 www.iosrjournals.org 44 |Page Effects of biodiesel and Hydrotreated Vegetable Oil on the performance and exhaust emissions of a stationary diesel engine M. Atzemi 1 , E. Lois 1 , I. Kosyfologou 1 1 (School of Chemical Engineering, National Technical University of Athens, Greece) Corresponding Author: M. Atzemi Abstract: The increasing use of renewable fuels in transportation is a prime environmental target so much for the European member states, as much for the rest of the world, in order to reduce the dependency on fossil oil, as well as the pollutant emissions. Renewable biofuels, such as Hydrotreated Vegetable Oil (HVO) and Fatty Acid Methyl Esters (Biodiesel) are promising substitutes of conventional diesel fuel for compression ignition (CI) engines. In this study the physicochemical properties of biodiesel from used cooking oils and HVO were examined, when blended in different concentrations with an ultra-low-sulfur diesel. Four blends for each biofuel (up to 40% v/v) were evaluated according to EN 590. The effects of the biofuels and the eight mixtures on engine performance and exhaust emissions were studied in a stationary diesel engine, operating under various loads. The results of the present research showed that HVO displayed reductions up to 14.8% in low and medium loads for nitrogen oxides (NOx) emissions and decreased carbon monoxide (CO) in all engine loads, compared to conventional diesel. Biodiesel produced less CO than diesel only in high loads, but increased nitrogen oxides (NOx) by almost 15% in high engine loads. Significant decreases were observed with both biofuels in particulate matter (PM) emissions. Keywords: biodiesel, HVO, paraffinic diesel, exhaust emissions --------------------------------------------------------------------------------------------------------------------------------------- Date of Submission: 18-01-2019 Date of acceptance: 02-02-2019 --------------------------------------------------------------------------------------------------------------------------------------- I. Introduction Diesel engines have for many decades dominated the medium and medium-large transportation sector. In recent years, the number of diesel engines in the automotive market has significantly increased, particularly in Europe. In 2017, diesels’ market share was 44,8% of total passenger car registrations in the EU-15 [1]. Despite theiradvantages, reliability, fuel efficiency and turbocharging capability, diesel engines also exhibit drawbacks, regarding the exhaust emissions [2]. Their levels of particulate matter (PM) and nitrogen oxides (NOx), due to the high flame temperature and the diffusive combustion, are considerable and are raising awareness [3]. The increasing concerns about the depletion of fossil fuel resources and their negative environmental impact have triggered interest on the potential benefits of biofuels. Biodiesel (FAME) has been well accepted as a renewable alternative to diesel fuel globally. It is an environmentally friendly, free of sulfur, non-toxic biofuel, which can be produced from the transesterification of edible or non-edible vegetable oils, waste vegetable oils and animal fats. Its usage in diesel engines, as a substitute of diesel, can reduce harmful tailpipe combustion emissions (CO, PM and unburned hydrocarbons), as well as the greenhouse gas emissions [4]–[8]. The quality of biodiesel is known to depend on feedstock [9]–[11]. Although biodiesel is an environmentally attractive fuel, it is characterized by several disadvantages, such as poor oxidation stability, deposit formation, lower calorific value, high feedstock cost and microorganism degradation [12]–[15]. Another factor that makes the use of biodiesel less attractive is the increase of NOx emissions, as has been reported by numerous researchers. This increase is more significant as the content of biodiesel rises in diesel fuel [16]–[20]. It was noticed that the greater increase of NOx emissions occurred during high engine loads, due to the higher combustion temperatures. The most important mechanism for the production of NOx is the formation of thermal NOx described by the so-called Zeldovich mechanism. Thermal NOx is believed to be the predominant contributor to total NOx [21]. Hydrotreating of vegetable oils is a modern and promising way to produce very high-quality biobased diesel fuels (HVO) without compromising fuel logistics, engines, exhaust after treatment devices, or exhaust emissions [22], [23]. In this process hydrogen is used to remove oxygen from the triglyceride vegetable oil molecules and to split the triglyceride into three separate chains, thus creating hydrocarbons similar to existing diesel fuel components. HVO can be produced from various feedstocks, such as vegetable oils, animal fats and waste oils, without affecting the properties of the final product [24]. HVO is a mixture of straight chain and branched paraffins, without any aromatics. Consequently, it has a very high cetane number (75-95) and lower