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    CO2 reduction in a common rail direct injection engine using the combined effect of low carbon biofuels, hydrogen and a post combustion carbon capture system
    (Taylor & Francis, 2021) Varuvel, Edwin Geo; Thiyagarajan, S.; Sonthalia, Ankit; Prakash, T.; Awad, Sary; Aloui, Fethi; Pugazhendhi, Arivalagan
    The transportation sector is a major emitter of carbon dioxide emissions. It is a known fact that carbon dioxide is the cause of global warming which has resulted in extreme weather conditions as well as climate change. In this study a combination of different methods of expediting the CO2 emission from a single cylinder common rail direct injection (CRDI) engine has been explored. The methods include use of low carbon content biofuels (lemon peel oil (LPO) and camphor oil (CMO), inducing hydrogen in the intake manifold and zeolite based after-treatment system. Initial engine operation with the low carbon content biofuel blends resulted in reduced smoke and CO2 emissions. Substitution of the blends with hydrogen further assisted in decrease in emission and improvement in engine efficiency. Later on in the exhaust pipe an after-treatment system containing zeolite was placed. The emissions were found to reduce even further and at full load condition the lowest CO2 (39.7% reduction) and smoke (49% reduction) emissions were observed with LPO blend and hydrogen induction. The NO emission with hydrogen induction increases for both the blends, however, it was seen that the zeolite based treatment system was effective in reducing the emission as well. As compared to baseline diesel, the maximum reduction in NO emission was 23% at full load with LPO blend, hydrogen induction and after-treatment system.
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    Experimental assessment on the performance, emission and combustion characteristics of a safflower oil fueled CI engine with hydrogen gas enrichment
    (Elsevier Ltd, 2022) Praveena, V.; Joseph Shobana Bai, Femilda Josephin; Balasubramanian, Dhinesh; Devarajan, Yuvarajan; Aloui, Fethi; Varuvel, Edwin Geo
    Inducting hydrogen with biodiesel in a compression ignition (CI) engine contributes to improvising the performance characteristics of the engine and minimize long-term issues. Combustion of hydrogen along with intake air impacts positively in air quality by preventing the formation of toxic emissions like hydrocarbons (HC) and carbon monoxide (CO). The benefits of hydrogen such as good diffusion rate, lesser ignition energy and fast flame propagation rate promotes a more homogenously mixed air fuel ratio. This experimental work focuses on enhancement of the performance and combustion characteristics of a direct injection compression ignition (DICI) engine by enriching the biodiesel with various levels of hydrogen gas supplement at the intake manifold. The brake thermal efficiency of the engine with safflower oil biodiesel is 31.15 % which is far inferior to that of diesel with 34 %. As an effort to improve the performance characteristics of the CI engine, hydrogen gas is inducted at 4 %, 8 % and 12 % energy share. HC, CO and smoke emission decreases by 15.09 %, 34.6 % and 18 % respectively compared to neat biodiesel at full load of 5.2 kW. An opposite trend is observed in NOx emissions which are raised from 1650 ppm to 1852 ppm. A 12.2 % increase in NOx emissions are realized due to homogenous flammable mixture that combusts closer to Top dead center (TDC). The hydrogen enrichment with safflower oil biodiesel influences the combustion characteristics in a positive vein except for the NOx emissions, which could be minimized through the use of retrofit devices like selective catalytic reducer, diesel oxidation catalyst etc.
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    A systematic review on biofuel production and utilization from algae and waste feedstocks- a circular economy approach
    (Pergamon-Elsevier Science Ltd, 2024) Praveena, V.; Martin, Leenus Jesu; Matijosius, Jonas; Aloui, Fethi; Pugazhendhi, Arivalagan; Varuvel, Edwin Geo
    Energy demand on a global measure grows continuously due to increased population, industrialization and economic growth. Fossil fuel resources that are currently available are definitely not sufficient to meet the growing demand. In addition, the continuous emissions from automobiles and industrial sectors should be attended to so that a complete remedial and sustainable alternative for fossil fuels is obtained. The appropriate replacement for fossil fuel is biofuel, as they are renewable and eco-friendly. First generation and second generation biodiesel derived from various sources are extensively researched and experimented practically by the past researchers. This article summarizes a continuous and comprehensive assessment of different feedstocks needed for third and fourth generations of biodiesel. Various sources of feedstock, steps for biodiesel production, yield of biodiesel obtained through different methods, properties of biodiesel like fatty acid profile, density, viscosity, cetane number, flash point, cloud point, economic feasibility and considerations are also discussed. Third generation biodiesel like microalgae can be widely used in CI engines. It is observed that their performance and combustion analysis in a CI engine is determined by the physico chemical properties of obtained biodiesel and nature of feedstock. Species selection and cultivation methods of microalgae, future perspectives of cultivating techniques and lipid production are summarized in detail. Fourth generation biodiesel like solar fuels and synthetic biomass production are covered, though their application in various energy fields is still not revealed. The type of transesterification that best suits the free fatty acid profile of fuel is selected and other reaction parameters like reaction time, reaction temperature, catalyst quantity and oil methanol molar ratio are explained individually for third generation feedstocks. Proper adoption of suitable methods would help in yielding the maximum biodiesel. Future energy demand can be dealt with by the combination of various third and fourth generation oil feedstocks.