Wyniki wyszukiwania - Biblioteka Nauki

1

Rola wodoru w inżynierii i eksploatacji warstwy wierzchniej

100%

Kula P.

Zeszyty Naukowe Politechniki Świętokrzyskiej. Mechanika

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2000

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tom Z. 72

131-143

PL

W pracy omówiono genezę poznania, teorię i praktykę zużycia wodorowego części maszyn., jak również technologiczne metody przeciwdziałania tej katastrofalnej postaci eksploatacyjnego niszczenia tworzyw metalowych. Przedstawiono wyniki badań porównawczy odporności na objętościowe nawodorowanie próbek poddanych różnym procesom powierzchniowej obróbki cieplnej i cieplno-chemicznej. Zaproponowano i potwierdzono wynikami badań doświadczalnych model niejednorodnego stężenia wodoru w utwardzanych warstwach wierzchnich wytwarzanych poprzez różnorodne odmiany procesu azotowania. Na jego podstawie wyprowadzono teoretycznie i potwierdzono doświadczalnie zjawisko "smarowania wodorem" przy tarciu suchym. Wykazano również korelacji pomiędzy zawartością wodoru w warstwie wierzchniej a trwałością warstwy granicznej oleju w warunkach smarowania elastohydrodynamicznego.

EN

The subject of the paper is the hydrogen's behaviour in the field of surface engineering, as well as during friction both in dry and lubricated frictional couples. The recently discovered phenomena, namely: the blocking of hydrogen diffusion by nitrided layers, selflubrication by hydrogen and the activity of absorbed hydrogen in the chemisorption of lubricants have been presented and explained.

2

Future hydrogen technologies in power engineering and semi-closed gas turbine system

100%

Iki N. , Hama J. , Takahashi S. , Miller A. , Kiryk S.

Prace Naukowe Politechniki Warszawskiej. Mechanika

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1999

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tom z. 181

97-106

EN

This paper introduces one of the utilisation of the hydrogen as a power systems` fuel in Japanese program, which has been progressed to establish the global energy network by using hydrogen as a secondary clean energy. And it introduces semi-closed gas turbine systems with steam recirculation. They are not only capable of the high efficiency with hydrogen-oxygen combustion but useful with fuel-oxygen combustion for CO(sub 2) separation. This paper also describes the key technologies to evaluate the possibilities of a semi-closed gas turbine system with higher efficiency.

PL

Niniejszy artykuł przedstawia jedną z możliwych technologii wykorzystania wodoru jako paliwa dla systemów wytwarzania energii, zaproponowaną w japońskim programie badawczym. Program ten ma za zadanie stworzenie globalnej sieci energetycznej z wykorzystaniem wodoru jako wtórnego nośnika czystej energii użytkowej. Przedstawiono także układ z turbiną gazową i recylkulacją pary, który może z dużą sprawnością produkować energię zarówno dla spalania wodór-tlen, jak też dla spalania gaz/olej-tlen przy separacji CO(sub 2). W artykule wymieniono kluczowe technologie, których rozwój ma wpływ na uzyskanie wysokiej sprawności powyższego układu.

3

The current state and prospects for hydrogenisation of motor transport in Northwestern Europe and Poland

85%

Gis M. , Gis W.

Combustion Engines

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2022

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tom R. 61, nr 3

61--71

EN

The article presents the situation regarding the hydrogenisation of motor transport in Northwestern Europe, a region leading in this regard in Europe. The following countries were included in the analysis of national plans in this area, taking into account both technical issues - among others - concerning HRS and FCEV, their number, as well as economic issues (among other things relating to the costs of using hydrogen): Belgium, Denmark, France, Germany, the Netherlands, Norway and England. Reference was also made to the situation in Poland, where major fuel and energy companies (among others: Orlen, Lotos, PGNiG and ZE PAK Capital Group) are strongly interested in hydrogenisation of motor transport and manufacturers of vehicles - for example - Solaris or Autosan in producing vehicles equipped with fuel cells. Based on the analyses carried out at the Institute of Motor Transport, it was found that the good location of basic hydrogen refuelling stations is along the TEN-T corridors running across Poland. The order of their location is as follows: 1 - Poznan, 2 - Warsaw,3 - Bialystok, 4 - Szczecin, 5 - Łódź region, 6 - Tricity, 7 - Wroclaw, 8 - Katowice region, 9 - Kraków.

4

Studies of PEM-type Fuel Cell System Cooperating with the Generation of Hydrogen

80%

Węcel D. , Ogulewicz W. , Wiciak G. , Łukowicz H.

Archivum Combustionis

|

2010

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tom Vol. 30 nr 3

247-260

EN

Selected problems connected to the use of fuel cells in energy-system are introduced in the paper. The studies concerning the system for electricity and heat generation, consisting of a photovoltaic panels, hydrogen generators and PEM-type fuel cell are presented. For the generation of hydrogen with the use of electrolysis method electricity generated by renewable energy sources is used. A system for transformation of the electricity generated in photovoltaic panels and used for powering hydrogen generators was developed and realized. The fuel cells used consist of two stacks of electrical output, 360 W each. They are equipped with a complex supply system of: hydrogen fuel, air, cells cooling together with regulatory and protection system. It allowed to make the analysis of working parameters of the fuel cell for different electrical loads and with various amounts of supplied air, as well as for different conditions of cell cooling. The developed system for data collecting and acquisition allows for simultaneous recording of the data from all elements of the measuring position. The aim of the study is the development of a demonstration installation of an autonomous system for electricity generation using renewable energy sources and having the possibility of hydrogen fuel storage, in the case of reduced electricity demand.

5

The future of the hydrogen economy : bright or bleak?

80%

Bossel U. , Eliasson B. , Taylor G.

Journal of KONES

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2004

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tom Vol. 11, No. 1-2

87-111

EN

In the past, many have considered the production and use of hydrogen, assuming that it is just another gaseous fuel and can be handled much like natural gas in todays energy economy. With this study we present an analysis of the energy required to operate an elemental hydrogen economy, with particular reference to rond transport. High-grade electricity from renewable or nuclear sources is needed not only to generate hydrogen, hut also for all the other essential stages. However, because of the molecular structure of hydrogen, the infrastructure is much more energy-intensive than in an oil and natural gas economy. In a "Hydrogen Economy" the hydrogen like any other commercial product, is subject to several stages between production and use. Hydrogen has to be packaged by compression or liquefaction. transported by surface vehicles or pipelines, stored, and transferred to the end user. Whether generated by electrolysis or by chemistry, and even produced locally at filling stations, the gaseous or liquid hydrogen has to undergo these market processes before it can be used by the customer. Hydrogen can also be derived chemically at relatively Iow cost from natural gas or other hydrocarbons. However as there are no energetic or environmental advantages, we do not consider this option. In this study, the energy consumed by each stage is related to the true energy content - the higher heating value (HHV) - of the delivered hydrogen. The analysis reveals that much more energy is needed to operate a hydrogen economy than is required for fossil energy supply and distribution today. In fact, the input of electrical energy to make, package, transport, store and transfer hydrogen may easily exceed the hydrogen energy delivered to the end user - implying an well-totank efficiency of less than 50 per cent. However, precious energy can be saved by packaging hydrogen chemically in a synthetic liąuid hydrocarbon like in ethanol or ethanol. To de-couple energy use front global warming, the use of "geocarbons" from fossil sources should be avoided. However, carbon atoms from biomass, organic waste materials or recycled carbon dioxide could become the carriers for hydrogen atoms. Furthermore, energy intensive electrolysis may be partially replaced by the less energy intensive chemical transformation of water and carbon to natural and synthetic hydrocarbons, including bio-methanol and bio-ethanol. Hence, the closed natural hydrogen (water) cycle and the closed natural carbon (CO2) cycle may be used to produce synthetic hydrocarbons for a post-fossil fuel energy economy. As long as the carbon comes from the biosphere ("bio-carbon"), the synthetic hydrocarbon economy would be far better than the elemental hydrogen economy - both energetically and environmentally.

6

Evaluation of the possibility to improve the efficiency of SI engine fueled with low-carbon gaseous fuels

80%

Kubica G.

Journal of Mechanical and Transport Engineering

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2014

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tom Vol. 66, No. 1

39--50

EN

A detailed analysis of the issues related to improving the efficiency of energy conversion in spark ignition engine, powered by low-carbon gaseous fuels are presented in that monograph. The research was conducted on engine powered by compressed natural gas (CNG), and methane/hydrogen blends. Selected for tests group of fuels was consisted of eight blends, with various hydrogen share (by volume): 0% (pure methane), 5%, 10%, 15%, 20%, 30%, 40% i 50%. The object of the research was a 4-cylinder engine with a capacity of 1.6 dm3, the pre-installed in car Opel Astra F. The engine was equipped with an alternative CNG injection system. An influences of ignition advance angle and fuel composition on engine performance and total efficiency were determined in the final analysis. The proposed solutions were compared with the base configuration of the power supply in the summary of work.

PL

W artykule przedstawiono szczegółową analizę zagadnień związanych z poprawą efektywności konwersji energii w silniku o zapłonie iskrowym, zasilanym paliwami gazowymi o zmniejszonym udziale węgla. W badaniach stanowiskowych silnik zasilano sprężonym gazem ziemnym (CNG) oraz mieszaninami metanu z wodorem. Obiektem badań był 4-cylindrowy silnik o pojemności 1,6 dm3, zamontowany fabrycznie w samochodzie Opel Astra F. Jednostkę napędową wyposażono w alternatywną instalację zasilania wtryskowego CNG. W końcowej analizie określono wpływ kąta wyprzedzenia zapłonu i składu paliwa gazowego na podstawowe wskaźniki pracy silnika i jego ogólną sprawność. W podsumowaniu porównano proponowane rozwiązania z bazową konfiguracją układu zasilania.

7

Possibilities for the production and use of hydrogen as a fuel in existing boilers

80%

Sigal O. , Paderno D. , Nizhnyk N.

Journal of New Technologies in Environmental Science

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2022

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tom Vol. 6, nr 2

65--66

EN

The process scheme is developed for climate neutral production and use of hydrogen as a fuel in existing boilers at heat supply enterprises.

8

The effect of hydrogen transported through a gas pipeline on the functioning of gas compression station work

80%

Zabrzeski Ł. , Janusz P. , Liszka K. , Łaciak M. , Szurlej A.

AGH Drilling, Oil, Gas

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2017

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tom Vol. 34, no. 4

959--968

EN

The production of hydrogen based on excess electricity and transporting it by pipeline as a mixture with natural gas may be an excellent completion of an energy system. When dealing with gas transmission over long distances, gas compression stations become an integral part of the natural gas grid, providing desired pressure of this source of power in pipes. In this paper the effect that hydrogen admixture has on the main parameters of the operation of gas compression stations was described.

9

SCC of austenitic alloys in PWR water simulated with molecular dynamics

80%

Arnoux P.

Advances in Materials Science

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2007

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tom Vol. 7, nr 1(11)

6-12

EN

The aim of this work is to propose a model to explain the microscopic mechanism of Stress Corrosion Cracking (SCC) in PWR water of stainless steels or nickel base alloys. Molecular Dynamics (DM) simulations on bicrystal or Ni have been carried out with hydrogen at the grain boundary (GB) (Eta 5). Two temperatures have been tested : IK and 562K. Literature reports that Transmission Electronic Microscopy analysis at the crack tip (CT) reveals the presence of an oxide. As this oxide bas a 15% lattice parameter higher than the alloy, it induces a pressure on the crack lips (CL). The role of this pressure and hydrogen will be particularly addressed. Simulations without hydrogen nor pressure on the CL shows ductile fracture with blunting of the CT. On the contrary, when a compressive strength is applied on the CL and hydrogen is present at the GB, the rupture is brittle with a GB cleavage. A SCC model bas been inferred from these results.

10

Investigation of combustion, performance and emission characteristics of spark ignition engine fuelled with buthanol – gasoline mixture and a hydrogen enriched air

80%

Rimkus A. , Melaika M. , Matijošius J. , Mikaliūnas Š. , Pukalskas S.

Advances in Science and Technology. Research Journal

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2016

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tom Vol. 10, nr 31

102--108

EN

In this study, spark ignition engine fuelled with buthanol-gasoline mixture and a hydrogen-enriched air was investigated. Engine performance, emissions and combustion characteristics were investigated with different buthanol (10% and 20% by volume) gasoline mixtures and additionally supplied oxygen and hydrogen (HHO) gas mixture (3.6 l/min) in the sucked air. Hydrogen, which is in the HHO gas, improves gasoline and gasoline-buthanol mixture combustion, increases indicated pressure during combustion phase and decreases effective specific fuel consumption. Buthanol addition decreases the rate of heat release, the combustion temperature and pressure are lower which have an influence on lower nitrous oxide (NOx) emission in exhaust gases. Buthanol lowers hydrocarbon (HC) formation, but it increases carbon monoxide (CO) concentration and fuel consumption. Combustion process analysis was carried out using AVL BOOST software. Experimental research and combustion process numerical simulation showed that using balanced buthanol and hydrogen addition, optimal efficient and ecological parameters could be achieved when engine is working with optimal spark timing, as it would work on gasoline fuel.

11

Badania wiązania wodorowego - zastosowanie metod instrumentalnych

80%

Jabłońska M.

Analityka : nauka i praktyka

|

2008

|

tom nr 1

11-16

12

Degradation processes in ammonia synthesis conditions

80%

Číhal V. , Stránský K.

Zeszyty Naukowe. Mechanika / Politechnika Opolska

|

2001

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tom Vol. 279, z. 72

67-72

EN

Nitriding by ammonia synthesis gas causes a modification of the carbides, a decarburization and sensitization to hydrogen corrosion within a relatively thin metal layer near to the inner surface of the converters. Subsequently a sensitization to hydrogen attack occurs due to the reaction of diffusing hydrogen with carbon released by the carbides and a decar-burization by carbon diffusion to the surface. High local internal stresses perpendicular to the surface caused by surface nitriding lead to small inter-granular separations parallel to the surface without any significant effect on the integrity of the pressure vessel. As the nitrided layer hinders further nitriding of the steel, this phenomen is without any long-term consequence. On the other hand, if sufficiently high load and/or residual stresses apply in the axial or tangential direction to the vessel wall, cracks have to be expected propagating slowly across the wall, as crack growth is controlled by diffusion of nitrogen and carbide transformation. Consequently, the Nelson diagram for NH3-containing synthesis gas should be applied with only great care. Efforts are necessary to quantify as well the critical stress level for crack initiation, as the propagation rate of such cracks is controlled by nitrogen diffusion and the complex carbide reactions finish by chemically induced hydrogen cracking - hydrogen corrosion.

13

Studies of atmospheric - pressure microwave plasmas used for gas processing

80%

Mizeraczyk J. , Jasiński M. , Nowakowska H. , Dors M.

Nukleonika

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2012

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tom Vol. 57, No. 2

241-247

EN

This paper concerns the atmospheric-pressure microwave plasmas and their applications, mainly for gas processing. Several types of atmospheric-pressure microwave sources (MPSs), i.e. surface-wave-sustained MPS, nozzle-type MPSs, nozzleless MPSs, plasma-sheet MPSs and microwave microplasma sources - MmPSs (antenna- and coaxial-line- -based) as well as their performance are presented. The presented experimental results on the optimization of selected MPSs are confronted with results of the modelling of the electromagnetic field in them. The paper deals also with the applications of MPSs for the processing of gases. Two types of the plasma gas processing were experimentally tested: decomposition of volatile organic compounds (VOCs) and reforming of VOCs (mainly methane) into hydrogen. Results of the laboratory experiments on the plasma processing of several highly-concentrated (up to 100%) VOCs, including freon-type refrigerants, in the waveguide-supplied MPSs showed that the microwave discharge plasma is capable of fully decomposing the VOCs at relatively low energy cost. The use of waveguide-supplied coaxial-line-based and metal-cylinder-based nozzleless MPSs to methane reforming into hydrogen turned out to be energetically efficient. These selected results show MPSs to be an attractive tool for gas processing, including the harmful gas decomposition and production of useful gases.

14

Comparative preliminary unit costs analysis of the operation of passenger cars with combustion engines and fuel cell vehicles powered by hydrogen

80%

Gis W. , Waśkiewicz J. , Menes M. , Gis M.

Journal of KONES

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2019

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tom Vol. 26, No. 4

69--74

EN

The article presents political and legal aspects regarding the recommendation for the development of hydrogen technology in the economy and in transport. The development of electric cars with hydrogen-powered fuel cells, which took place in recent years in the world, has been outlined. The principles of calculation of average vehicle operating costs applicable in the transport economics are discussed. The estimated average unit operating costs of a statistical passenger car using conventional energy carriers, estimated in the studies of the Motor Transport Institute are quoted. The assumptions and results of the estimation of the average cost per 1 vehicle-kilometre of the electric passenger car’s mileage (BEV) have been presented, as well as the assumptions and results of the estimation of the average unit operating costs of a hydrogen powered passenger car (FCEV). The average unit costs of the mileage of these vehicles have been compared. The predictions regarding the future changes in the average prices of FCEV vehicles have been cited and the average unit costs of operating electric cars with fuel cells by the 2050 have been estimated. The project of administrative support for the development of low-emission transport in Poland was indicated.

15

CFD modeling of passive autocatalytic recombiners*

80%

Orszulik M. , Fic A. , Bury T.

Nukleonika

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2015

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tom 60

|

nr 2

347-353

EN

This study deals with numerical modeling of passive autocatalytic hydrogen recombiners (PARs). Such devices are installed within containments of many nuclear reactors in order to remove hydrogen and convert it to steam. The main purpose of this work is to develop a numerical model of passive autocatalytic recombiner (PAR) using the commercial computational fluid dynamics (CFD) software ANSYS-FLUENT and tuning the model using experimental results. The REKO 3 experiment was used for this purpose. Experiment was made in the Institute for Safety Research and Reactor Technology in Julich (Germany). It has been performed for different hydrogen concentrations, different flow rates, the presence of steam, and different initial temperatures of the inlet mixture. The model of this experimental recombiner was elaborated within the framework of this work. The influence of mesh, gas thermal conductivity coefficient, mass diffusivity coefficients, and turbulence model was investigated. The best results with a good agreement with REKO 3 data were received for k-ɛ model of turbulence, gas thermal conductivity dependent on the temperature and mass diffusivity coefficients taken from CHEMKIN program. The validated model of the PAR was next implemented into simple two-dimensional simulations of hydrogen behavior within a subcompartment of a containment building.

16

Evaluation of passive autocatalytic recombiners operation efficiency by means of the lumped parameter approach*

80%

Bury T.

Nukleonika

|

2015

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tom 60

|

nr 2

339-345

EN

The problem of hydrogen behavior in containment buildings of nuclear reactors belongs to thermal-hydraulic area. Taking into account the size of systems under consideration and, first of all, safety issues, such type of analyses cannot be done by means of full-scale experiments. Therefore, mathematical modeling and numerical simulations are widely used for these purposes. A lumped parameter approach based code HEPCAL has been elaborated in the Institute of Thermal Technology of the Silesian University of Technology for simulations of pressurized water reactor containment transient response. The VVER-440/213 and European pressurised water reactor (EPR) reactors containments are the subjects of analysis within the framework of this paper. Simulations have been realized for the loss-of-coolant accident scenarios with emergency core cooling system failure. These scenarios include core overheating and hydrogen generation. Passive autocatalytic recombiners installed for removal of hydrogen has been taken into account. The operational efficiency of the hydrogen removal system has been evaluated by comparing with an actual hydrogen concentration and flammability limit. This limit has been determined for the three-component mixture of air, steam and hydrogen. Some problems related to the lumped parameter approach application have been also identified.

17

Investigation of Stress Corrosion Cracking in Magnesium Alloys by Quantitative Fractography Methods

80%

Sozańska M. , Mościcki A. , Chmiela B.

Archives of Metallurgy and Materials

|

2017

|

tom Vol. 62, iss. 2A

557--562

EN

The article shows that the use of quantitative fracture description may lead to significant progress in research on the phenomenon of stress corrosion cracking of the WE43 magnesium alloy. Tests were carried out on samples in air, and after hydrogenation in 0.1 M Na2SO4 with cathodic polarization. Fracture surfaces were analyzed after different variants of the Slow Strain Rate Test. It was demonstrated that the parameters for quantitative evaluation of fracture surface microcracks can be closely linked with the susceptibility of the WE43 magnesium alloy operating under complex state of the mechanical load in corrosive environments. The final result of the study was the determination of the quantitative relationship between Slow Strain Rate Test parameters, the mechanical properties, and the parameters of the quantitative evaluation of fracture surface (microcracks).

18

Hydrogen rich gases combustion in the IC engine

80%

Szwaja S.

Journal of KONES

|

2009

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tom Vol. 16, No. 4

447-454

EN

Experimental results of combusting three different syngases in an internal combustion (IC) spark ignition engine are presented in this paper. The syngases used for tests varied each from the other with hydrogen content, which was of 10,15 and 60%. Other combustible gases as CO and CH4 were also changed. Thus, the lower heating value of the syngases was of 2.7, 4.6 and 17.2 MJ/nm3, respectively. Combustion tests were performed at stoichiometric ratio of syngas-air mixture, with variable spark timing and constant compression ratio of 10. On the basis of in-cylinder combustion pressure histories the indicated mean effective pressure (IMEP) was computed and presented versus spark timing and vs location of the middle combustion phase expressed by the 50% of mass fraction burned (MFB). Additionally, the 0-10% MFB and 10-90% MFB were also determined. Furthermore, the paper contains theoretical determination of the three fuel quantities, which can affect combustion duration and heat release rate during burning the syngases in the IC engine. They are as follows: laminar flame speed, ignition delay and adiabatic flame temperature. Final results does not show satisfactory correlation between LFS computed at NTP and real combustion phasing. Furthermore, both long combustion duration and long 0-10% MFB leading to unstable combustion were observed for the syngas with the lowest LHV of 2.7 MJ/nm3.

19

A numerical and experimental study of marine hydrogen–natural gas–diesel tri–fuel engines

80%

Zhao R. , Xu L. , Su X. , Feng S. , Li C. , Tan Q. , Wang Z.

Polish Maritime Research

|

2020

|

tom nr 4

80--90

EN

Maritime shipping is a key component of the global economy, representing 80–90% of international trade. To deal with the energy crisis and marine environmental pollution, hydrogen-natural gas-diesel tri-fuel engines have become an attractive option for use in the maritime industry. In this study, numerical simulations and experimental tests were used to evaluate the effects of different hydrogen ratios on the combustion and emissions from these engines. The results show that, in terms of combustion performance, as the hydrogen proportion increases, the combustion ignition delay time in the cylinder decreases and the laminar flame speed increases. The pressure and temperature in the cylinder increase and the temperature field distribution expands more rapidly with a higher hydrogen ratio. This means that the tri-fuel engine (H2 +CH4 +Diesel) has a faster response and better power performance than the dual-fuel engine (CH4 +Diesel). In terms of emission performance, as the hydrogen proportion increases, the NO emissions increase, and CO and CO2 emissions decrease. If factors such as methane escape into the atmosphere from the engine are considered, the contribution of marine tri-fuel engines to reducing ship exhaust emissions will be even more significant. Therefore, this study shows that marine hydrogen-natural gas-diesel tri-fuel engines have significant application and research prospects.

20

Anomalously large kinetic isotope effect

80%

Krinkin D.

Open Chemistry

|

2007

|

tom 5

|

nr 4

1019-1063

EN

Activated diffusion of water between macromolecules in swollen cellulose is accompanied by anomalously high kinetic isotope effects of oxygen. The separation factor of heavy-oxygen water (H218O /H216O) is thousands of permilles instead of tens of permilles according to modern Absolute Rate Theory. This anomalous separation under usual conditions is disguised by the opposing process of very fast equalization to equilibrium through water-filled cellulose pores. This process is quicker by approximately 3 orders of magnitude than diffusion through the cellulose body. As a consequence, this opposition-directed equalization virtually eliminates the results of isotope separation. To reveal this anomaly it is necessary to suppress equalization, which was the primary problem for both discovery of this anomaly and its investigation. The method of investigating the anomalous separation in cellulose was developed with suppression of this negative influence. Discussion of the theoretical nature of the anomalous kinetic isotope effect is presented. This theoretical study would probably permit the discovery and use for isotope separation of the anomalously high isotope effect for other chemical elements, in particular, for those heavier than oxygen. [...]