Study on combustion, performance and exhaust emissions of bioethanol-gasoline blended spark ignition engine

Bioethanol production from pineapple fruit waste juice using bakery yeast

The declining oil production stemming from decreasing raw material reserves has clashes with rising demands and has created a supply-demand gap in the overall energy sector. Excessive consumption of fossil fuel oil exacerbates environmental issues, potentially leading to global climate change and increased natural disasters. Consequently, there are efforts in looking for alternate renewable fuel sources. The study included physical pre-treatment, natural hydrolysis, natural fermentation, fermentation of pineapple waste juice using bakery yeast, and subsequent distillation. The pineapple wastes produced juice with 12.67 °Brix and pH range of 3.16-3.18. The present study reports bioethanol production from pineapple waste mixed with bakery yeast (Saccharomyces cerevisiae ) and pineapple wastes juice without bakery yeast, revealing that the yeast-amended mixture yielded bioethanol with alcohol content of 45 % compared to 36 % from pineapple juice alone. Re-distillation enhanced bioethanol content from 25 % - 45 %-85 % which aligns well with E85 fuel specifications, indicating bioethanol's suitability as fuel. Thus, bioethanol derived from pineapple fruit wastes presents a promising renewable energy solution. This study investigates the production of bioethanol from pineapple waste juice by comparing two methods: one using bakery yeast and the other without yeast. Both methods are conducted at room temperature to evaluate their efficiency and effectiveness in converting pineapple waste juice into bioethanol.

Kinetic modeling of ion formation during diesel combustion with different fuel injection timing

Ions are formed during the combustion process in internal combustion engines. The measurement of ions inside the combustion chamber produces reliable information about the combustion process. The present study focuses on the formation of ions inside the combustion chamber of diesel engines with different injection timing. For this purpose, a multi-zone thermodynamic model is utilized to simulate the closed cycle of the engine. To understand the kinetic behavior of the ions, the model is connected to an ionic chemical kinetics mechanism with 336 reactions and 81 species. Six important ionic reactions comprising 5 ions are used in the ionic mechanism. Dvode differential equation solver is also employed to calculate the energy and kinetics equations. The developed model has an acceptable accuracy in predicting the performance and pollutants of diesel engines. Based on the results, the ion formation is delayed by delaying the fuel injection timing. The maximum amount of in-cylinder ions depends on injection timing. In-cylinder ion current can predict the start of combustion accurately.

Engineering of Saccharomyces cerevisiae for co-fermentation of glucose and xylose: Current state and perspectives

The use of non-food lignocellulosic biomass to produce ethanol fits into the strategy of a global circular economy with low dependence on fossil energy resources. Xylose is the second most abundant sugar in lignocellulosic hydrolysate, and its utilization in fermentation is a key issue in making the full use of raw plant materials for ethanol production and reduce production costs. Saccharomyces cerevisiae is the best ethanol producer but the organism is not a native xylose user. In recent years, great efforts have been made in the construction of xylose utilizing S. cerevisiae strains by metabolic and evolutionary engineering approaches. In addition, managing global transcriptional regulation works provides an effective means to increase the xylose utilization capacity of recombinant strains. Here we review the common strategies and research advances in the research field in order to facilitate the researches in xylose metabolism and xylose-based fermentation.

Characteristics of SI engine fueled with BE50-Isooctane blends with different ignition timings

The effect of various ignition timing on spark ignition (SI) engines with bioethanol-isooctane mixtures has been widely studied. In the present studies, we used three different ignition angle positions, namely 9°, 12°, and 15° BTDC to increase the combustion pressure in the combustion chamber. In addition to macroscopic observations through engine performance, observations are also carried out from a molecular perspective, i.e.; atomic, bond, and bond angle properties of bioethanol-isooctane fuel. The result shows that more atoms of the isooctane carbon chain are non-rotatable (23 atomic bonds) than the 8 bonds of the bioethanol carbon chain. Furthermore, isooctane also has a wider bond angle (around 121.1745°) than the bond angle of ethanol (around 110.0476°). The unique properties of the atoms in the carbon chains of these two fuels have a direct impact on engine performance. The results show that the viscosity of bioethanol is lower when compared to isooctane, which indicates that the bioethanol molecules are more reactive and flammable. The result also found that at an ignition angle of 12° the BE50 engine has the best performance. Moreover, the test results also show that bioethanol produces clean combustion as evidenced by the lowest CO and HC gas emissions.

Four stroke diesel engine performance and emission studies of ethanol recovered from Kappaphycus alvarezii reject -solid food waste mixed substrates and its blends

Bioethanol is an eco-friendly green fuel, owing to its production from sustainable bio-based sources. In this study, bioethanol (BE) is produced from Kappaphycus alverezii reject (KR) blended with Solid Food Waste (SFW). This bioethanol is blended with petroleum-based diesel (PBD) in the following proportions: 15%, 20% and 25% for further studies. Performance characteristics, specifically Brake Specific Fuel Consumption (BSFC), Brake Thermal Efficiency (BTE), Brake Power (BP) and exhaust emissions, mainly Carbon monoxide (CO), Carbon dioxide (CO₂), Smoke Opacity (SO), hydrocarbons (HC) and oxides of Nitrogen (NO_X) have been investigated. The blended test fuels show better results, which is confirmed by the performance characteristics of BTE being lower than PBD. The emission report shows lesser CO (0.12%) and SO (59.6%) compared to PBD (0.14% and 67.2%), signifying the clean-burning tendency of BE blends. From the findings, PBD75: BE25 is an excellent fuel blend for improving flow properties, engine performance, and emission characteristics.

Low-carbon alcohol fuels for decarbonizing the road transportation industry: a bibliometric analysis 2000-2021

The application of low-carbon alcohols (LCA fuels) in internal combustion engines has become one of the most important topics in road transport decarbonization. This paper aims to identify the trends and characteristics of LCA combustion research for the period 2000-2021 through bibliometric analysis. Citation analysis is used to evaluate the influence of most productive journals, countries/regions, authors, institutions, and relevant literature, while collaborative network between various authors, countries/regions, institutions, and the co-occurrences among different keywords are discussed. A dataset of 2250 publications was extracted from the Web of Science Core database and analyzed with CiteSpace and Biblioshiny. The extracted documents involve 429 journals of publications by 4782 authors from 1434 institutions across 83 countries/regions. The results reveal that the research output in this field has undergone three main stages of development, i.e., initial development (2000-2007), slow development (2008-2015), and rapid development (2016-2021). Currently, the research field is growing at an annual growth rate of 9.24%, with most of the contributions by authors and institutions originating from China. The analysis from relevant keywords and literature suggests that the core of this research field centers on the combustion, performance, and emission characteristics of LCA-fueled engines. The current study helps keep the scientific community informed of the latest paradigms in the LCA combustion research field.

Assessment of ethanol autoxidation as a drop-in kerosene and surrogates blend with a new modelling approach

Bioethanol has been considered as a more sustainable alternative for fossil fuels, and it has been used as a drop-in fuel mixture. In this paper, the autoxidation properties of real kerosene as well as single, binary and ternary surrogates with the presence of ethanol are investigated for the first time. A simplified python code is proposed to predict the pressure drop of the PetroOXY method that was used for assessing the fuel autoxidation properties. The experimental results show that the addition of an ethanol concentration reduces the induction period of real kerosene while increasing that of surrogate mixtures. Also, the maximum pressure during the PetroOXY test increases with the increase of ethanol concentration. The model is able to predict the induction period of ethanol accurately by employing an automated reaction mechanism generator. A strategy to increase the autoxidation stability of ethanol by adding 1 g/L antioxidant has been evaluated. The efficiency of the antioxidants for ethanol is in the following order: PY > Decalin > DTBP > Tetralin > BHT > MTBP > BHA > TBHQ > PG.

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Autoxidation of real and surrogates kerosene was evaluated using PetroOXY method.

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Ethanol addition decreases the induction period of real kerosene while increases that of surrogates.

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Nine antioxidants were assessed to improve the thermal stability of ethanol.

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A new method for modelling PetroOXY test is proposed.