Combustion of Gaseous Alternative Fuels in Compression Ignition Engines

The problem of alternative fuels for combustion engines has been growing in importance recently. This is connected not only with decreasing fossil fuel resources, but also with the growing concern for the natural environment and the fight against global warming. This paper discusses the possibility of utilizing alternative gaseous fuels in compression-ignition engines, using dual-fuel, gas-liquid operation strategy. Current state of the art of this technology had been introduced, along with its benefits and challenges to be countered. The discussion had been supported by authors own research experience on dual-fuel engines. The latest results of research on the impact of gas composition on combustion process in the Common Rail dual fuel engine had been presented, at the same illustrating the environmental benefits of using gaseous fuels. The Utilization of gaseous fuels with varying composition was illustrated systematically, starting with natural gas. The possibility of using fuels with lower content of methane (the so-called low-calorie gases) was shown by the impact of depleting natural gas with carbon dioxide. Industrial gases, such as syngas contain a large amount of hydrogen, carbon monoxide or higher hydrocarbons (ethane, propane). The possibility of fueling CI engines with these gasses was presented by the influence of enriching natural gas with mentioned components. The results cover engine dynamometer tests for different operating conditions with the analysis of the combustion process and detailed emission measurements discussion. The results of experimental studies were supplemented by simulation results, using mathematical models, developed by the authors for multi-fuel enginesr

Ternary fuel mixture of diesel, rapeseed oil and tyre pyrolytic oil suitable for modern CRDI engines

The focus on seeking alternative fuels for combustion engines has been on the environmental and political scene for many years. Simultaneously there is a more and more serious problem of non-degradable waste utilization. In the present work an attempt has been made to asses both of those aspects by proposing a tailor-made, 3-component mixture consisting of mineral diesel, crude rapeseed oil and waste tyre pyrolytic oil. It was proven that the addition of pyrolytic oil can improve some basic drawbacks of rapeseed oil / diesel mixtures like high density and viscosity or low cold filter plugging point. On the basis of maximum bio-component share and optimum physicochemical properties a best fuel sample (40% mineral diesel oil, 55% rapeseed oil and 5% pyrolytic oil fraction) had been selected for engine tests, performed on a light-duty multi-cylinder Compression Ignition (CI) engine with electronic, Common Rail (CR) injection system. The steady state tests were performed for two rotational speeds and two injection strategies (single and sequential fuel injection), for each of which a full load sweep was performed. The engine research included in-cylinder pressure analysis along with efficiency estimation and exhaust gas emission measurements. The research confirmed the assumption that the selected fuel mixture is suitable for modern CI engines. The specific fuel consumption was similar or lower for the tested fuel compared to standard diesel, except the cases were sequential injection was incorporated. Emissions remained on similar levels as for both fuels except Total HydroCarbons (THC) at sequential injection operation points, which correlated with lower fuel conversion efficiency

Combustion engine applications of waste tyre pyrolytic oil

There is abundant worldwide research into combustion engine applications for tyre pyrolysis oil (TPO). However, many of these studies demonstrate conflicting or ambiguous results, so although the huge number of used tyres promises good availability for TPO, its role as fuel for transport applications is still uncertain. This review´s goal is to clarify the case for TPO as transport fuel by means of a critical, wide-ranging and updated review of TPO's engine applications. The work gathers, collates and analyses the results of over 200 influential original research papers, aiming to answer the governing research questions related to TPO production and quality, post-processing and quality improvement and its final end-use engine validation. The work re-evaluates the environmental aspects of TPO technology, setting it against the latest backdrop of growing climate change concern and the urgency to find alternative fuels. The hard economics of TPO are also addressed, for example, assessing other end-of-life tyre management routes and competing fuel alternatives. The critical discussion on the key issues, including the most relevant drivers and boundaries, points towards TPO's use as a fuel component in marine, off-road and heavy-duty road applications. The results indicate that state-of-the-art production methods yield fuel that could be used directly in bunkering chains for marine transport as low-sulphur fuel oil. Discussion reveals that automotive applications are limited to blends not exceeding 10% tyre pyrolytic oil: sulphur and polyaromatic hydrocarbons contents and particulate emissions are the main constraints. Pyrolysis process efficiency is high and feedstock for TPO is both available and flexible. Waste tyre-derived pyrolytic oils could function as a supplementary solution to biofuels, blended to take advantage of their complementary properties. The particular added value of this review is that it bridges the latest knowledge from several domains related to TPO fuel: industrial management, process chemistry, fuel science and combustion/engine research. The resultant analysis is expressed in terms that are accessible to all those domains. It underlines how studies from an individual domain perspective fail to produce the holistic view. The review creates a route towards modern multidisciplinary research supporting TPO´s role in global transition to circular economy.©2021 Elsevier. This manuscript version is made available under the Creative Commons Attribution–NonCommercial–NoDerivatives 4.0 International (CC BY–NC–ND 4.0) license, https://creativecommons.org/licenses/by-nc-nd/4.0/fi=vertaisarvioitu|en=peerReviewed

Effect of Various Sodium Chloride Mass Fractions on Wheat and Rye Bread Using Different Dough Preparation Techniques

This study assessed the selected properties of bread with reduced amount of sodium chloride. The bread was made from white and wholemeal wheat flour and rye flour. The dough was prepared using three techniques: with yeast, natural sourdough or starter sourdough. Sodium chloride was added to the dough at 0, 0.5, 1.0 and 1.5 % of the flour mass. The following bread properties were examined in the study: yield and volume of the loaf, moisture content, crumb firmness and porosity, and organoleptic properties. Reducing the mass fraction of added sodium chloride was not found to have considerable effect on bread yield, whereas it had a significant and variable effect on the loaf volume, and crumb firmness and porosity. Organoleptic assessment showed diverse effects of sodium chloride addition on sensory properties of bread, depending on the type of bread and the dough preparation method. Reduced mass fractions of sodium chloride changed the organoleptic properties of bread made with yeast and with starter sourdough to a greater extent than of bread prepared with natural sourdough

Performance and emission characterization of a common-rail compression-ignition engine fuelled with ternary mixtures of rapeseed oil, pyrolytic oil and diesel

Biofuels are one of the short-term alternatives for reducing the well-to-wheel greenhouse gas footprint of transport. In the framework of compression-ignition engine fuels. This study investigates the feasibility of using cold-pressed rapeseed oil as a biocomponent, admixed with distilled tyre pyrolytic oil, as an energy-efficient alternative to commonly considered methyl ester-based mixtures in diesel fuel. Selected ternary and binary fuel blends are subjected to engine tests. Their scope covers 80% of the engine map and aims at identifying tradeoffs between fuel composition, engine performance and emissions. The results show that fuel mixtures containing a large fraction of rapeseed oil (up to 55% by volume) can be effectively combusted when pyrolytic oil distillate is introduced as the additive. The deterioration in brake efficiency for such fuel does not exceed 1.2% with respect to diesel baseline. At the same time, the results are superior in terms of both efficiency and emissions when compared to FAME-based biodiesel. Finally, with indicated efficiencies on a similar level as the diesel baseline, suggesting improved burning rate with pyrolytic oil addition, the study identifies parasitic losses in fuel injection equipment as a significant contributor to the overall efficiency penalty for the examined ternary mixtures.fi=vertaisarvioitu|en=peerReviewed

Svojstva kruha od pšeničnog i raženog brašna u ovisnosti o masenom udjelu soli i metodi pripreme tijesta

This study assessed the selected properties of bread with reduced amount of sodium chloride. The bread was made from white and wholemeal wheat flour and rye flour. The dough was prepared using three techniques: with yeast, natural sourdough or starter sourdough. Sodium chloride was added to the dough at 0, 0.5, 1.0 and 1.5 % of the flour mass. The following bread properties were examined in the study: yield and volume of the loaf, moisture content, crumb firmness and porosity, and organoleptic properties. Reducing the mass fraction of added sodium chloride was not found to have considerable effect on bread yield, whereas it had a significant and variable effect on the loaf volume, and crumb firmness and porosity. Organoleptic assessment showed diverse effects of sodium chloride addition on sensory properties of bread, depending on the type of bread and the dough preparation method. Reduced mass fractions of sodium chloride changed the organoleptic properties of bread made with yeast and with starter sourdough to a greater extent than of bread prepared with natural sourdough.U radu su ispitana odabrana svojstva kruha proizvedenog od pšeničnog ili raženog brašna dobivenog meljavom oljuštenog ili cijelog zrna, s manjim udjelom soli. Tijesto za kruh je pripravljeno na tri načina: fermentacijom pomoću pekarskog kvasca, spontanom fermentacijom, te dodatkom starter kulture, i to bez dodatka ili s dodatkom 0,5; 1 and 1,5 % soli. Ispitana su sljedeća svojstva: prinos i volumen kruha, udjel vlage, čvrstoća i poroznost mrvica, te organoleptička svojstva kruha. Smanjenje udjela soli nije bitno utjecalo na prinos kruha, no znatno je utjecalo na volumen kruha te čvrstoću i poroznost mrvica. Organoleptičko ispitivanje pokazalo je da udjel soli različito utječe na senzorska svojstva kruha, ovisno o upotrijebljenom tipu brašna te metodi pripreme tijesta. Smanjenjem udjela soli bitnije su izmijenjena organoleptička svojstva kruha pripravljenog pomoću pekarskog kvasca ili uz dodatak starter kulture nego onog dobivenog spontanom fermentacijom