Iskanje po katalogu digitalne knjižnice

Opis: Plastic is one of the most widely used materials worldwide. The problem with plastic arises when it becomes waste, which needs to be treated. One option is to transform plastic waste into synthetic fuels, which can be used as replacements or additives for conventional fossil fuels and can contribute to more sustainable plastic waste treatment compared with landfilling and other traditional waste management processes. Thermal and catalytic pyrolysis are common processes in which synthetic fuels can be produced from plastic waste. The properties of pyrolytic oil are similar to those of fossil fuels, but different additives and plastic stabilizers can affect the quality of these synthetic fuels. The quality of fuels and the permissible particle sizes and number density are regulated by fuel standards. Particle size in fuels is also regulated by fuel filters in vehicles, which are usually designed to capture particles larger than 4 µm. Problems can arise with the number density (quantity) of particles in synthetic fuels compared to that in fossil fuels. The present work is a numerical study of how particle size and number density (quantity) influence cavitation phenomena and cavitation erosion (abrasion) in common-rail diesel injectors. The results provide more information on whether pyrolysis oil (synthetic fuel) from plastic waste can be used as a substitute for fossil fuels and whether their use can contribute to more sustainable plastic waste treatments. The results indicate that the particle size and number density slightly influence cavitation phenomena in diesel injectors and significantly influence abrasion.
Ključne besede: plastic waste, synthetic fuels, pyrolytic oil, common rail, cavitation, erosion, particles
Objavljeno v DKUM: 05.07.2024; Ogledov: 131; Prenosov: 14
Celotno besedilo (3,06 MB)
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Opis: In the present study engine/vehicle responses from a standardized transient test cycle are estimated using 13 stationary operating regimes following a previously developed methodology. The main advantage of the methodology tested is that allows obtaining an estimation of transient parameters in a stationary test bench, which requirements are much less demanding than those of the transient test bench. The objectives are: in one hand, to demonstrate that the methodology correctly estimates engine responses regardless of the fuel tested, as it is proposed in a previous paper and, on the other hand, to improve the methodology and the accuracy of the estimated parameters. The fuels tested are renewable fuels from different raw materials (biodiesel from rapeseed, sunflower, and soybean), and diesel fuel as the reference. Biodiesels were tested neat and blended (30% v/v) with diesel fuel. The engine is a common-rail light-duty one, and the standardized testing procedure used to illustrate the implementation of the methodology is the New European Driving Cycle (NEDC). Two design of experiments (DoE) of 13 runs each were analyzed. One of the DoE tested was proposed for characterizing the NEDC, referred as to CTDoE design, while the other one is a five-level fractional factorial design (FFDoE) that adequately matches the optimality criteria of orthogonality, D-optimal criterion, rotatability, and space-filling. The original methodology was improved by the implementation of a new fitting function that simulates the cold start effect over the engine parameters and by an new definition of the boundary in the [n,M] domain. These improvements showed significantly higher accuracy of the estimated engine parameters obtained, both instantaneous and accumulated, respect to the original methodology. The results obtained based on the application of the FFDoE design support the feasibility of the methodology tested. Engine performance and regulated emissions responses, such as intake air and fuel mass flow rate, thermomechanical exergy rate, exhaust gas residual heat rate, total hydrocarbons (THC), nitrogen oxides (NOx), carbon monoxide (CO) and particulate matter (PM) emissions from a transient test were instantaneously and cumulatively predicted with high accuracy using the engine responses from 13 steady-state operating modes.
Ključne besede: simulation, light duty diesel engine, transient cycle, biodiesel, design of experiments, cold start correction function
Objavljeno v DKUM: 21.09.2023; Ogledov: 350; Prenosov: 30
Celotno besedilo (13,39 MB)
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Opis: In this paper bioethanol/diesel and bioethanol/biodiesel blends, at several concentrations and temperatures, are studied to find its possible commercial usage as a fuel to run a diesel power plant. The tested fuels were: net mineral diesel fuel (D100) , 5 % bioethanol/diesel fuel blend (v/v) (E5D95), 10 % bioethanol/diesel fuel blend (v/v) (E10D90), 15 % bioethanol/diesel fuel blend (v/v) (E15D85), neat biodiesel (B100), 5 % bioethanol/biodiesel blend (v/v) (E5B95), 10 % bioethanol/biodiesel blend (v/v) (E10B90), and 15 % bioethanol/biodiesel blend (v/v) (E15B85). The fuels were tested at: 30, 25, 8and -18 C. This paper shows the observations done in 8 samples during 5 weeks. After each week, each sample was overviewed, and changes related to stability, colour and aggregation were recorded. It has been proved that additives are not necessary to ensure stability of bioethanol/biodiesel blends under low temperature conditions, as the phase separation never happens.But in case of bioethanol/diesel blends some additives are necessary to keep stability under low temperature conditions. Based on this study, it can be concluded that blends of biodiesel fuel with bioethanol up to 15% can be used to fuel a diesel power plant if engine performance tests corroborate it. The same conclusion can be applied to blends of diesel fuel with bioethanol up to 15% blends if additives to keep stability are added.
Ključne besede: alternative fuel, biodiesel, bioethanol, heat engines, fuels blend
Objavljeno v DKUM: 31.05.2012; Ogledov: 2554; Prenosov: 0