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1

Numerical study of internal flue gas recirculation system applied to methane-hydrogen powered gas microturbine combustor

Fąfara Jean-Marc, Modliński Norbert

Combustion Engines

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2023

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R. 62, nr 1

63--77

EN

Sources of renewable energy have been increasingly used all over the world. This kind of energy is highly desirable because of its unlimited availability. Unfortunately, renewable energy production very much depends on weather conditions. Consequently, it is necessary to store the produced excess energy in order to use it when needed. There is a technology able to produce a hydrogen/methane fuel from excess renewable energy, which may be stored. This technology is called the Power-to-Gas technology (P2G). Since the efficiency of this technological process depends on the hydrogen fraction in the renewable energy fuel, there is a need to increase this fraction. Concurrently, the gas microturbine technology is increasingly widely used in various industries (aviation, energy, automotive, military, etc). The P2G technology and the gas microturbine technology are likely to be integrated in the near future and, as mentioned above, the hydrogen fraction in the methane-hydrogen fuel will tend to increase. In order to power a gas microturbine with the methane-hydrogen fuel, it will be necessary to modify the combustor to avoid an excessive temperature increase and flashbacks. In this paper it is proposed to apply an autonomous internal exhaust gas recirculation system to resolve the hydrogen combustion problems indicated above. The operating principle and the proposed design of the recirculation system and the latter’s impact on the combustor’s operating parameters and emissivity (NOx and CO) are presented.

2

Comparative analysis of the heat balance results of the selected Tier III-compliant gas-fuelled two-stroke main engines

Korlak Kamil

Combustion Engines

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2023

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R. 62, nr 2

24--28

EN

Two-stroke engines are distinguished by the highest overall efficiency among all main engines. This is not only due to the low speed, and large piston stroke, but also to the high combustion temperature, which results in an increase in nitrogen oxides (NOx) emission. Technical solutions applied to bring main engines into compliance with current NOx emission standards set by the Tier III limits include the use of SCR and EGR systems, the implementation of the Otto cycle, and the application of liquified natural gas (LNG) as the low-emission fuel. Impact of the available Tier III-compliant technologies on the heat balance results is analysed using the example of the currently most popular dual-fuel main engines, i.e. WinGD X92DF and MAN G95ME-C10.5-GI. The possibilities of waste heat recovery in the electricity generation process and thereby improving the ship energy efficiency are discussed.

3

Numerical investigation of the internal flue gas recirculation system applied to methane powered gas microturbine combustor

Fąfara Jean-Marc, Modliński Norbert

Combustion Engines

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2021

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R. 60, nr 4

21--29

EN

The gas microturbines gain significance in various industry sectors. One of their most crucial advantages is the capability of utilizing variety of fuels. At the same time, the emissions regulations become increasingly strict. This is why there is a need to look for a new technological solution to limit the emissions of selected substances, like carbon monoxide (CO) and nitrogen oxides (NOx). The internal recirculation of the flue gases is well known to limit the temperature peak and for the homogenization of the temperature field gradient in different combustion chambers. This paper presents a numerical investigation of a novel internal flue gas recirculation system applied to gas microturbine combustors. The ability to perform an internal exhaust gases recirculation by adding a combustor internal pipe system was verified numerically. This paper exposed the numerical investigation methods and obtained results. The study presents the concept and results performed on three cases of internal exhaust gases recirculation systems applied to a reference combustor. The work permitted to demonstrate numerically that it is possible to perform an autonomous exhaust gases recirculation inside gas micro-turbine combustor at a maximum global rate of 0.51%, and that the recirculation system has an impact on the combustion processes without specially modifying the combustor work parameters.

4

The influence of non-cooled exhaust gas recirculation on the diesel engine parameters

Cisek J.

Combustion Engines

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2017

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R. 56, nr 4

269--273

EN

This paper presents the results of the diesel engine research on the energy performance, components of exhaust gases and smoke and parameters related to the supply system for VW 1.9 TDI working in 2 modes: with standard, non-cooled EGR system, and without this system. All of measurements were carried out on the some engine speed – 2000 rpm (speed of maximum engine torque) and various engine loads. It was found that the serial engine control unit switches the EGR system off above 150 Nm engine load (Momax = 295 Nm). In this range of load the engine running with EGR is characterized by higher fuel consumption (lower total efficiency) ca. 5%, compared with engine without EGR. Concentration of NOx in exhaust gases was lower up to 45% but, at the same time, exhaust gas smoke and concentration of carbon oxides were strongly increasing. It can be seen that EGR system increases the temperature (up to 110°C) and changes the composition of air-exhaust gas in the intake manifold. One of reason of this fact is self-changing start of injection. Additional effect of EGR is lower air pressure behind turbocharger, because the flow of exhaust gases (into EGR) is taken before the turbine.

5

The influence of non-cooled exhaust gas recirculation on the indicator diagrams and heat release parameters in diesel engine cylinder

Cisek J.

Combustion Engines

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2017

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R. 56, nr 4

283--288

EN

This paper presents the results of the diesel engine research on the indicator and heat realized diagrams for VW 1.9 TDI working in 2 modes: with standard, non-cooled EGR system, and without this system. All of measurement was carried out on the some engine speed – 2000 rpm (speed of maximum engine torque) and various engine load. Some of the analyzed parameters were read directly from the measurement systems (e.g. indicator diagrams) or engine controller (e.g. start of injection) and the rest of them had to be calculated. The calculation of rate of heat release (δQ/dα) was based on the well-known mathematical model. When the exhaust gas recirculation valve is open, the maximum of combustion pressure and rate of maximum kinetic heat release (δQk/dα)max are smaller than when the valve is closed. These facts are connected with the shorter self-combustion delay for engine working with EGR. But this is also associated with reduction of the rate of maximum diffusion heat release (δQd/dα)max, which means that more particulates (PM) are excreted into the atmosphere. This fact explains e.g. significantly higher smog of exhaust gases for diesel engine which works with EGR system. The analysis results show that exhaust gas recirculation system slightly deteriorates the energetic parameters of VW 1.9 TDI engine, but, at the same time, significantly reduces the level of toxic nitrogen oxides in exhaust gases.

6

Impact of EGR control at in-cylinder pressure and ecological properties of CI off-road vehicle engine

Bieniek A., Mamala J., Graba M., Hennek K.

Combustion Engines

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2017

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R. 56, nr 3

88--95

EN

An attempt has been made to clarify the effect of wide-ranging control of the exhaust gas recirculation system on the cylinder pressure and ecological engine performance. This publication contains the results of tests performed on the CI (compression ignition) engine of the off-road vehicle mounted on the test bench. The study was based on advanced EGR control with a proportional valve and a very efficient exhaust gases cooling system. Analysis of the test results is based on the cylinder pressure and the concentration of NOx and PM components at exhaust gases. The study included the influence of the exhaust gas recirculation system control on parameters such as differential pressure, MBF, and relative NOx and PM emissions. As demonstrated by the analysis conducted, the EGR valve control method and the exhaust gas cooling intensity significantly affect the cylinder pressure and its ecological performance.

7

Analysis of the possibilities to achieve adiabatization process of combustion surrounded by inactive gases in Rapid Compression Machine

Cieślik W., Pielecha I.

Combustion Engines

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2017

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R. 56, nr 1

27--31

EN

In this work non-combustible gases impact on combustion processes studies is performed. Research was performed in a optically accessible rapid compression machine (RCM) under spark ignition engine conditions. The distribution of the swirl charge in the relation to adopted for analysis sequence of gas delivery to the chamber was varied with regard to the main injection. Authors investigate the influence of these sequence on the combustion and the ignition delay of the main injection and the overall combustion characteristics. The aim of this work is the experimental recognition of possibilities of creating combustible mixtures of light hydrocarbon fuels surrounded by non-combustible gases affecting the function of the inhibitor. Specifying the ability of preparation and combustion of mixtures in such systems enables the scientifl analysis of adiabatization of the combustion process of fuel-air mixtures in the operating chambers. Theoretical analysis of the issues indicates possibility of obtaining such a stratification of the charge, that the inactive exhaust gases creating the outer ring surround the combustible mixture inside in such a way as to reduce the amount of heat exchanged between the working medium and the walls of the cylinder.

8

Dedicated exhaust gas recirculation in spark ignition engines

Rehan S.

Advances in Science and Technology. Research Journal

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2017

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Vol. 11, no 2

44--50

EN

The impact of high levels of exhaust gas recirculation (EGR) has been well documented to decrease fuel consumption and reduce emissions of spark ignition engines. But there are also many limitations associated with this technology like EGR control and tolerance, which can reduce the potential efficiency improvements. A new concept called D-EGR has been presented in which the exhaust from a sub group of power cylinders is channeled back to the intake of all the cylinders. In this literature review both experimental and numerical analysis of this technology is shown. In the former case experiments were performed on 2.0 L PFI engine with gasoline as a fuel in part and high load conditions and the results show that at part loads the D-EGR engine can lead to lower Brake Specific Fuel Consumption, lower HC and CO emissions and higher brake thermal efficiency. At high load operations the results show improved combustion stability and superior knock tolerance. In the numerical studies it shows comparable thermal efficiency with conventional spark ignition (SI) engines and reduction in NOX emissions.

9

Gas turbines – technological development and potential use in CAES systems

Jakowski D., Dzida M.

Combustion Engines

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2016

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R. 55, nr 2

46--53

EN

This article briefly describes Compressed Air Energy Storage (CAES), focusing on the technological development of one of the key elements of such systems – the gas turbines. It presents the basic parameters and features of gas turbines, as well as turbine classes with example models. Main tendencies in the structural and technological development are discussed. Changes and trends on electric energy markets are becoming more and more dependent on sources with flexible operating characteristics, therefore, the advantages of gas turbines and the reasons for their development are listed as well.

PL

W artykule przedstawiono krótką charakterystykę magazynowania energii w sprężonym powietrzu (CAES), skupiając się na przeglądzie osiągnięć technologicznych jednego z podstawowych elementów tych układów – turbin gazowych. Opisano podstawowe parametry i cechy turbin gazowych, a następnie klasy turbin z przykładowymi modelami. Przedstawiono główne tendencje w rozwoju konstrukcyjnym i technologicznym. Zmiany i trendy na rynkach energii elektrycznej coraz bardziej zależą od źródeł o elastycznej charakterystyce pracy, dlatego zestawiono również zalety i powody rozwoju turbin gazowych.