Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 32

Liczba wyników na stronie
first rewind previous Strona / 2 next fast forward last
Wyniki wyszukiwania
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 2 next fast forward last
EN
This article presents the results of investigations focused on the role of molecularly ordered structures (molecular clusters) on combustion process. The proposed new mechanism of the reactions initiation takes into account the role of molecular clusters in energy (heat and energy of electrons emitted by the surface of the walls of combustion chamber) conductivity regulation. Literature survey shows that molecular clusters created by aromatic hydrocarbons are responsible for particulate matter. The combustion process itself is not uniform in whole combustion chamber. Such diversity, caused mainly by heterogeneous thermal state of combustion chamber is recognized as significant reason to create various products of combustion including carbon oxides, carbon dioxides and nitrogen oxides. Jet fuel and its blends with n-butanol and biobutanol in concentration from 10 to 75 % (V/V) were subjected to laboratory tests. Such blends were also tested on the test rig with a miniature turbojet engine – MiniJETRig. Engine operating parameters and carbon oxide emission were measured. The relations between electrical conductivity and parameters of engine test (e.g. temperature in selected points in combustion chamber) were assessed. Engine tests were carried out according to specific profile of engine test, which models different engine operating modes. The results of experimental investigations, shown in the article, initially confirm the proposed mechanism of the oxidation reactions initiation during combustion process.
EN
Hydrocarbon containing synthetic fuels represent a promising alternative fuels. Despite different chemical compositions, their properties should be similar to properties of mineral fuels, as they are designed for the same drive units. The basic parameter related to the protection of the adequate service life of the power supply devices, including precision pairs, is lubricity. Lubricity depends on a number of factors, including these related to the chemical composition of fuel components and operating additives introduced into fuels in order to modify their properties. The preliminary results of research on the effect of additives: lubricating, anti-corrosion and anti-electrostatic once, on the lubricating properties of a synthetic fuel are shown in the paper. It was observed that there are relations between the content of additives and the dynamics of film formation. It is significant that this does not apply only to the lubricating additive, but also the additive, which protects the correct electrostatic balance by providing sufficiently high electrical conductivity of the fuel. This may indicate that the formation of a lubricating film remains in relation to the intensity of energy transport from the lubricated surface to the molecules of lubricating additives inside the film. The results shown in the paper preliminary confirm the hypothesis, that synthetic components of fuels change the concentration of ordered molecular structures (which are present in mineral part of fuels and which can be responsible for energy transport inside the lubricating film), what resulted in worse fuel ability to create protective film, and anti-electrostatic additive improves lubricity of blends of synthetic and mineral components.
EN
The paper covers the mechanism of lubrication layer formation by fuels containing synthetic hydrocarbons and alcohols. Development of alternative fuels containing FAME, alcohols, and synthetic hydrocarbons has increased the interest in the mechanism of lubrication of fuelling systems parts. Fuel lubricity tests have been conducted using the HFRR and BOCLE testing rigs. Fuels under testing, both for CI engines and for aviation turbine ones, contained synthetic components: saturated hydrocarbons both of even and odd number of carbon atoms, and butanol, isomers. These components have been added to conventional fuels, such as diesel fuel and Jet A-1 fuel at the concentration of 0–20% (V/V). All fuels under testing contained commercially available lubricity improvers (carboxylic acid). Test results were analysed using model αi described in [L. 6, 7]. As a result of the analysis, it has been found that the liquid phase, which is a lubricating film, should contain agglomerates or molecular clusters responsible for the transport of energy introduced into lubricating film by electrons emitted from metal surface. The mechanism enabling a description of the effect of base fuel without lubricity improvers on efficiency of such additives has been suggested.
PL
Przedmiotem artykułu jest mechanizm tworzenia warstwy smarującej przez paliwa zawierające syntetyczne węglowodory i alkohole. Rozwój paliw alternatywnych spowodował wzrost zainteresowania mechanizmem smarowania elementów układów zasilania silników. Badania smarności paliw prowadzono z użyciem aparatów HFRR i BOCLE. Badane paliwa do silników o ZS i paliwa do turbinowych silników lotniczych zawierały trzy serie syntetycznych komponentów: węglowodory parafinowe o parzystej liczbie atomów węgla, węglowodory parafinowe o nieparzystej liczbie atomów węgla oraz izomery butanolu. Powyższe syntetyczne komponenty były dodawane do mineralnych paliw: oleju napędowego i paliwa Jet A1 w ilości 0–20% (V/V). Wszystkie badane paliwa zawierały komercyjnie dostępne dodatki smarnościowe (kwas karboksylowy). Wyniki badań eksperymentalnych były analizowane z zastosowaniem modelu αi opisanego w publikacjach [L. 6, 7]. W rezultacie przeprowadzonej analizy stwierdzono, że faza ciekła – film smarny powinna zawierać aglomeraty lub klastry molekularne, które są odpowiedzialne za transport energii wprowadzanej do filmu smarnego przez elektrony emitowane z powierzchni metalu. Zaproponowano mechanizm, który może wyjaśnić wpływ paliwa bazowego (bez dodatków smarnościowych) na efektywność działania dodatków smarnościowych.
EN
This paper discusses briefly the production technology of dimethyl ether, taking into account plant raw materials and the physical and chemical properties of DME as compared to diesel fuel. The benefits and disadvantages of DME as a fuel are presented and changes in the emission of harmful substances characterised as compared to the combustion of diesel fuel. Also, basic usage problems are addressed, e.g. the wear of engine’s elements, cavity and leakages in the fuel system.
EN
The article shows the current state of knowledge in the area of applying biohydrocarbons for fuel production, especially in aeronautical applications and to power compression-ignition engines. The technologies based on biochemical and thermal/chemical conversion of biomass are described. Technological potential of these technologies is evaluated. The article is based on the literature review.
PL
W artykule przedstawiono aktualny stan wiedzy w zakresie wykorzystania biowęglowodorów do celów paliwowych, szczególnie w zastosowaniach lotniczych i do zasilania silników z zapłonem samoczynnym. Opisano technologie oparte na biochemicznej i termicznej/chemicznej konwersji biomasy z uwzględnieniem możliwości technologicznych. Pracę oparto na przeglądzie literatury.
EN
The article described the possibilities of using biohydrocarbons as self-ignition fuels, aircraft or automotive fuel components on the basis of the biotechnology implemented in the industry.
PL
W artykule przedstawiono możliwości wykorzystania biowęglowodorów jako paliw samoistnych lub komponentów paliw lotniczych i samochodowych na podstawie wdrożonych w przemyśle biotechnologii. Zaprezentowano również koncepcje przeróbki składników biomasy w zakresie pozyskiwania komponentów paliwowych.
EN
In the paper, the concept of a model bench for accelerated ageing of bio-components and biofuels was presented. It is used to simulate the ageing process of biofuels and components of vegetable or animal origin, taking place during storage in the storage tanks. The construction of the bench’s essential elements and its equipment were designed and implemented in such a way as to mostly reflect actual storage conditions in large capacity tanks. An additional and unprecedented function of the bench includes the possibility to simulate the product transport conditions. Furthermore, a method of the test, with the use of simultaneously performed traditional tests on the physical and chemical properties monitored in the process of storage was presented. An analysis of the relation between values of the parameters obtained with different methods (on the model bench and under laboratory conditions) was conducted. In addition, their usefulness to assess the impact of logistic processes on the product quality was presented. In the paper, the results of the work executed within the framework of the project “Development of a prototype of the monitoring system the ageing rate and degree of bio-components and biofuels” within the Program Innovative Economy Operational Programme, Measure 1.4. “Support for goal-oriented projects” were used.
EN
The paper presents the results of investigations concerning a new method used for predicting the allowable time of storage of biocomponents – FAME. The method was based on laboratory research carried out with the use of a storage tank simulator. The aging process was carried out in the conditions increasing the reaction rate – at high temperature. There are several methods/procedures used for predicting the allowable time of storage of fuels and biocomponents – FAME, but all of them are based on tests at the temperature so high that the mechanism of aging process is different than the one observed in storage tanks. It was assumed that the aging process could be divided into two stages: at the first stage, the aging precursors are created and at the second stage, precursors are converted into the fuel aging products. These products lead to changes in fuel properties. The kinetics of precursor creation determines the rate of all reactions, which lead to the final aging products. It was found that the rate of reaction at the first stage of fuel aging can be effectively increased by an increase in temperature and even relatively high temperature does not change the mechanism of the creation of aging precursors. The method that has been worked out makes it possible to control the mechanism of aging process during quick laboratory tests. The products of aging processes were detected with the use of the IR-VIS spectrometry. The allowable time of storage was determined for several FAME samples on the basis of quick laboratory tests. The results of laboratory quick tests were verified by comparing them with the results of the aging process of FAME in storage tanks. On the basis of the test results, the algorithm of allowable time of FAME storage calculation was worked out.
EN
This paper presents differences between fossil fuel (Jet A-1) and alcohol/Jet A-1 blend, during combustion process using laboratory test rig with miniature turbojet engine (MiniJETRig). The test rig has been created in Air Force Institute of Technology for research and development works aimed at alternative fuels for aviation. Fuel from different feedstock (non-fossil sources) is introduced into market due to ecological aspects, fuel price stability and energy security. Application of alcohol to propel aircraft has started form using a blend of aviation gasoline with ethanol in spark-ignited internal-combustion engines. Taking into account that large part of aviation fuels used by commercial aircraft is jet fuels, so in this area it has begun to look for possibilities to apply alcohol component. In 2016, international standard (ASTM) approved a synthetic blending component for aviation turbine fuels for use in civil aircraft and engines – alcohol-to-jet synthetic paraffinic kerosene (ATJ-SPK). According to standard, ATJ-SPK synthetic blending components shall be comprised hydro processed synthetic paraffinic kerosene wholly derived from isobutanol processed through dehydration, oligomerization, hydrogenation and fractionation. Two different fuel samples, a traditional fossil jet fuel (Jet A-1) and a blend of 10% butanol with Jet A-1 were tested. Laboratory tests of selected physicochemical properties and bench tests with the same profile of engine test were carry out for both fuel samples. The obtained results: engine parameters and exhaust gas emissions are compared and discussed.
PL
artykule omówiony został problem starzenia chemicznego biokomponentów do paliw silnikowych. Problem ten stał się ważny dla jakości benzyn i oleju napędowego w sytuacji powszechnego dodawania bioetanolu i FAME. Badaniami objęto bioetanol i FAME przechowywane w różnych warunkach w laboratorium. Zastosowano do oce-ny stopnia zestarzenia biokomponentów standardowe metody badań oraz analizę spektroskopową w zakresie IR i chromatografię gazową. Przedstawiono wyniki badań bioetanolu i FAME przechowywanych przez 1 rok oraz wyniki analiz próbek bioetanolu i FAME przechowywanych w warunkach laboratoryjnych w różnych warunkach. W wyniku przeprowadzonych badań stwierdzono, że proces starzenia bioetanolu przebiega poprzez aldehyd octowy i acetal, a FAME trójetapowo poprzez epitlenki i nadtlenki. Stwierdzono także, że zanieczyszczenia biokomponentów, tj. woda i stałe produkty korozji zbiorników magazynowych przyspieszają procesy starzenia biokomponentów.
EN
The article explains the chemical processes responsible for aging of biocomponents during their storage. This problem is import ant for quality of gasolines and diesel fuel. The study involved bioethanol and FAME stored under different conditions in the laboratory. The standard methods and IR spectroscopy as well as gas chromatography were use for aging processes assessment. The obtained results showed that aging process of bioethanol runs through aldehyde and acetal. Aging of FAME runs through three stages which comprise epioxides and peroxides. It was found that water as well as solid contaminants increase the ratio of aging processes of bioethanol and FAME.
EN
A worldwide trend to popularise gradually increasing use of biofuels in various applications was a motivation for gaining interest in FAME as a commonly available biocomponent to fuels combusted in turbine engines. These engines are mainly used in aeronautics, but many of them are also used in other, non-aeronautical areas, including marine navigation. Specific conditions in which fuels are combusted in turbine engines used in these applications are the reason why fuel mixtures of kerosene and FAME type should reveal relevant low temperature characteristics. The article presents results of tests of low temperature properties of mixtures of the jet fuel Jet A-1 and methyl esters of higher fatty acids (FAME). The prepared mixtures contained different contents of FAME. The obtained results present changes of: viscosity, cloud point, pour point, crystallising point, and cold filter plugging point, depending on the percentage by volume of FAME. They also prove that the course of changes of low temperature properties of these mixtures is affected by chemical structure of the biocomponent.
EN
The paper describes the usability of current test methods employed in fuels for CI engines testing for fuels containing non-petroleum components. The paper describes test results that justify the necessity for test method modification and for establishing new criteria for assessment of such fuels usability. The analysis covered typical courses of friction coefficient and electrical contact potential as film thickness during test. During standard test the wear stages were isolated, and then referenced to actual operation of friction pair in fuel supply system of diesel engine. Test results show that methodology used up to date is not useful. The restriction to standard corrected wear scar diameter (WS 1.4) is not enough for proper interpretation of course and effects of model wear. Moreover, it is impossible to reference to actual operation conditions, which is inconsistent with tribological testing rules. Such rules mean that testing conditions reflect the actual ones as much as possible. Characteristics of test technique using HFRR, discussion on test method usability for testing the modified fuels, lubricity change vs. the increase of concentration of hydrocarbons typical for biohydrocarbons from Fischer-Tropsch process, comparison of changes of friction coefficient and lubrication film thickness for samples are presented in the paper.
EN
This paper describes the effect of fatty acid methyl esters (FAME) content in aviation fuels and diesel fuels on lubricity of such fuel blends. Standard petroleum fuels being currently in use contain various components, including the very important ones such as FAME and biohydrocarbons. The latter ones have been used also in aviation turbine fuels. Such use is, among others, associated with limiting of harmful combustion products emission. Lubricity, as one of important parameters related to fuel, directly effects on drive units use. Insufficient fuel lubricity effects probably on extended wear or injection system failure resulting in deterioration of combustion process, emission increase, and engine itself failure. Lubricity study included in this paper was carried out basing on standard test methods with HFRR and BOCLE. The paper describes the nature of lubricity change in relation to prepared fuel blends depending on FAME volume content, as well as the initial storage effect on test results.
EN
This paper describes the effect of long-term petroleum fuels storage on their characteristics that are significant for fuel and engine fuelling with this fuel. The paper shows the course of changes of selected fuels’ parameters that, according to the author, have the biggest effect on fuel quality maintaining during long-term storage. These changes were related to potential usage problems that would be the effect of them. The presented results are the part of the project with the goal to develop the system of reserves control. It’s pointed that there is necessary to continue work, especially aimed to create modern methodology to forecast the pace and nature of potential changes, not as so far - to evaluate the actual level of product under storage in actual or simulated-accelerated conditions.
EN
Research of usefulness of fuels for long-term storage is an important research of products of special use (meant for stock keeping as national or military reserves). Important fact is that fuels after storage should be used according to their initial use so their phisico-chemical and exploratory properties should remain the same during the whole storage cycle. Basic condition, enabling to foreseen that fuel will keep its quality at sufficient level in certain timeframe should be positive results of ageing tests. Below the doubts are presented whether methodology of evaluation is correct because of important differences in mechanisms of accelerated laboratory tests as well as real storage in typical conditions of storage tanks with large capacity. Differences in courses of chemical reactions and conditions of their initiation and course were pointed out. Scheme of equipment for marking content of existing gums, scheme of equipment for testing induction period, scheme of filtering and oxidizing equipment to test resistance of fuel to oxidation, effectiveness of collisions of molecules of reactants, scheme of chemical ageing process of fuels storaged in different temperature, function for different conditions ageing process of FAME, influence of value of potential molecules energy on initializing of chemical reactions are presented in the paper.
EN
This paper describes the analysis and conclusions regarding the use of butanol/biobutanol as a component of conventional mineral fuels employed in different areas of transportation. Butanol from biomass - biobutanol is interesting as biocomponent of gasoline, diesel fuel as well as aviation fuels. This is especially important in case of air transport, which is the carbon dioxide emission source of the fastest growth. Biobutanol is tested as biocomponent of gasoline, including aviation ones, but there are no information about biobutanol added to mineral Jet fuel as well as diesel fuel. Direction of research conducted by leading aviation companies indicates that hydrocarbon biocomponent will be main biofuel used as aviation turbine fuel. One of reported technology is focused on use of butane-1-ol as semi-finished products for isoparaffinic hydrocarbons generation that then would be used for aviation turbine fuels production. In order to do such analysis the preliminary lab testing of blends of butanol isomers with aviation fuel Jet A-1 and diesel fuel were performed. The paper contains the results of standard tests for blends of mineral fuels with butane-1-ol and butane-2-ol added in concentration of 0-20 %(V/V). Both the advantages and disadvantages regarding the use of such component of mineral fuels are presented. Butanol decreases value of flash point and significantly influence on conductivity of Jet fuel. In case of aviation fuel for turbine engines, and diesel fuel, the restrictions regarding direct use of butanol are important. However, butanol can be treated as semi-finished material for synthesizing of biohydrocarbons used in above applications.
17
Content available remote Wpływ surowca na właściwości estrów metylowych kwasów tłuszczowych (FAME)
PL
W niniejszej pracy przedstawione zostały wyniki badań wpływu surowca użytego do produkcji estrów metylowych kwasów tłuszczowych (FAME) na ich skład chemiczny oraz właściwości fizykochemiczne. Założono, że na podstawie wyników badania składu estrów oraz wartości wybranych parametrów jakościowych gotowego biokomponentu możliwe będzie określenie jego pochodzenia – w aspekcie zastosowanego surowca. W pracy przedstawiono zestawienia wybranych właściwości, na podstawie których można podjąć próbę identyfikacji surowca. Wyniki te można traktować jako wstępne, gdyż zidentyfikowano pewne relacje, których analizę należałoby kontynuować w celu uzyskania większej precyzji i selektywności oceny.
18
Content available remote Tendencja zmian wybranych parametrów „ekologicznych” paliw
PL
W niniejszym artykule przedstawiono zmiany, jakim ulegały na przestrzeni lat wymagania dotyczące zawartości siarki w paliwach do silników lądowych, morskich i lotniczych. Zmiany te są szczególnie widoczne dla benzyn silnikowych i oleju napędowego i związane są przede wszystkim z polityką proekologiczną zmierzającą do ograniczenia emisji związków siarki do atmosfery. Nieco inaczej przebiegają one dla paliw żeglugowych, z powodu m.in. specyficznych wymagań stawianych przez silniki okrętowe. W kwestii paliw lotniczych dopiero zaczynają się zmiany, ale paliwa te jeszcze nie są objęte normami ekologicznymi.
EN
The study outlines results from the studies on applicability of 1st generation biocomponent, namely long-chain fatty acid methyl esters (FAME) of vegetable origin, as an ingredient to fuels used to supply turbine aircraft engines. The presented analysis refers to both physical and chemical properties of developed fuel mixtures of Jet A-1 pure kerosene fuel with various amounts of the FAME additive and is based on own results obtained from tests of turbine engines on workbenches. The experiment results indicate that there are virtually no chances to apply the 1st generation biocomponents of the FAME type to aircrafts, however it is possible to seek for application opportunities of such biocomponents to other turbine engines, different from the aviation engineering.
PL
W niniejszej pracy przedstawiono wyniki oceny przydatności biokomponentu I generacji pochodzenia roślinnego – estrów metylowych wyższych kwasów tłuszczowych (FAME) – jako komponentu do paliwa stosowanego do zasilania turbinowych silników lotniczych. Przedstawiona analiza dotyczy zarówno badań właściwości fizykochemicznych przygotowanych mieszanek paliwa Jet A-1 z różną ilością dodatku FAME, jak również opiera się na wynikach uzyskanych na stanowiskach silników turbinowych. Wyniki pracy wskazują na praktyczny brak możliwości wykorzystania biokomponentu I generacji typu FAME w lotnictwie. Jednakże uzyskane rezultaty wskazują, że można poszukiwać zastosowania tego typu biokomponentu w silnikach turbinowych w innych dziedzinach niż lotnictwo.
first rewind previous Strona / 2 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.