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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

Wewnętrzny układ r ecyrkulacji spalin w mikroturbinach gazowych jako me toda do współspalania paliw z e zwiększonym udziałem wodoru

Fąfara Jean-Marc, Modliński Norbert

Zeszyty Energetyczne

|

2020

|

T. 7

107--127

PL

Niniejszy artykuł prezentuje podstawowe charakterystyki technologii Power-to-Gas (P2G), mikroturbin gazowych oraz zasadność i trudności wzajemnego integrowania powyżej wymienionych technologii. W dalszej części publikacji zostanie opisana nowa koncepcja samoistnego wewnątrzkomorowego zawracania spalin w komorach spalania mikroturbin gazowych, której zadaniem będzie umożliwienie zintegrowania technologii P2G z mikroturbinami.

5

Thermodynamic prediction of the effect of repeated recirculation of cooled flue gases on the content of major, minor, and trace compounds in oxy-coal combustion products

Jerzak Wojciech

Journal of Power Technologies

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2020

|

Vol. 100, nr 2

102--114

EN

This study investigates changes in the composition of oxy-coal combustion products resulting from the recirculation of cooled flue gas (FGR) at 20, 60, 100, 200, and 300°C (containing 70-95 mol% CO2). It presents the results of thermodynamic calculations describing changes in the content of the major, minor, and trace components of flue gases, ash and condensate. The results reflect a scenario of starting the oxy-coal combustion system in a fluidized bed boiler using low-purity oxygen from an air separation unit. This work demonstrates that in FGR loop the major species, i.e., Ar and N2, as well as the minor, e.g., Cl2, PbCl4, HgCl2, and CrOCl3, are accumulated. After nine FGR loops cooled to 300°C, marked increases in concentrations were observed: ZnCl2 and HCl (3-fold), as well as CrO2(OH)2 (2.5-fold). The ash that was formed contained, among others, CaSO4, SiO2, CaMgSi2O6, MgSiO3, ZnFe2O4, and MgCr2O4, whose mass changed in successive reactors asa result of the repeated FGR. Depending on the temperaturę of the cooling reactor, flue gases were subjected to recirculation and the main component of the condensate was H2O or H2SO4·6H2O. The condensate contained chloride salts, e.g.,PbCl2, KCl, and ZnCl2, as well as sulfate salts, i.e., K2SO4 and Na2SO4, in smaller amounts. A consequence of the nine-fold FGR cooled toT≤200°C was, among others, a percentage mass increase in ZnCl2in the condensate. The less cooling applied to flue gases, the more likely the occurrence of sulfates was in the condensate.

6

Solving the problem of air quality in Indian cities by retrofitting the EGR

Sroka Z. J., Walkowiak W., Reksa M., Kolanek C., Pillai C. V.

Combustion Engines

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2018

|

R. 57, nr 2

61--66

EN

This paper touches problem of transportation pollution focusing on NOx reducing in the India. There were India country chosen for study as the second populated country and most polluted cities in the world. As from statistics, it is known that more than 65% of Indian cars are old and they are the main reason of air pollution. Most of the old cars do not have any control measures for eliminating deadliest gases. Dumping the old cars is not possible, as the poor owns most of the old cars. For eliminating the pollution from old cars, the possible remedy is to control the emission of pollutants. Comparing to all gases in exhaust, nitrogen oxides are the dangerous one. It can may cause up to death. The best method to control the NOx gas is EGR (Exhaust Gas Recirculation) valves. This research mainly focuses on the possible ways of installing EGR in old engines and fabricate an EGR in one of the Indian cars. Maruti Suzuki 800 is best of for fabricating EGR, as it is a base model and most sold Indian car. As the result, there tremendous decreasing in NOx emission also the emission CO2 was reduced. The investigation about fabricating EGR in old vehicle results a positive output after calculated the cost of the fabrication, time consumption, work challenges and other facts. As Indian government adopt this concept, they can reduce the pollution from all types of vehicles to a great extend in few years of time with low investment.

7

Analysis of the impact of degree of recirculation of exhaust gases and energy fraction of gaseous fuel on overall efficiency and basic parameters of combustion process of dual-fuel diesel (self-ignition) engine fed by natural gas

Różycki A., Skrzek T.

Archiwum Motoryzacji

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2018

|

Vol. 79, nr 1

65--77

EN

In the Internal - Combustion Engines and Vehicles Division of the Humanistic-Technological University named after Kazimierz Pułaski in Radom there have been carried out research for many years on self-ignition dual-fuel engine with using different substitute fuels of low value of cetane number. Previous research showed possibilities of using considerable energy fractions of gaseous fuel [1, 8, and 9]. In the present paper there are presented selected results of research concerning utilization of natural gas. During execution of examinations it was observed that together with the change in energy fraction of gaseous fuel and change of degree of recirculation of exhaust gases the change of overall efficiency of engine as well as the change of parameters of combustion process takes place. In this paper there was made an attempt of evaluating the impact of application of different fractions of gaseous fuel and the degree of recirculation of exhaust gases on the parameters of combustion process. There was also made an attempt to clarify causes of the changes in values of overall efficiency as a result of observed changes in the course of combustion.

PL

W Zakładzie Pojazdów i Silników Spalinowych Uniwersytetu Technologiczno-Humanistycznego im. Kazimierza Pułaskiego w Radomiu od szereg lat są prowadzone badania dwupaliwowego silnika o zapłonie samoczynnym z wykorzystaniem różnych paliw zastępczych o małej wartości liczby cetanowej. Dotychczasowe badania wykazały możliwości stosowania znacznych udziałów energetycznych paliwa gazowego [1, 8, 9]. W niniejszym artykule zaprezentowano wybrane wyniki badań dotyczących wykorzystania gazu ziemnego. W trakcie badań zaobserwowano że wraz ze zmianą udziału energetycznego paliwa gazowego oraz zmianą stopnia recyrkulacji spalin zmianie ulega sprawność ogólna silnika a także parametry procesu spalania. W artykule podjęto próbę oceny wpływu stosowania różnych udziałów paliwa gazowego oraz stopnia recyrkulacji spalin na parametry procesu spalania. Podjęto także próbę wyjaśnienia przyczyn zmian wartości sprawności ogólnej w wyniku zaobserwowanych zmian przebiegu spalania.

8

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.

9

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.

10

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.

11

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.

12

A comparison of fuzzy logic and cluster renewal approaches for heat transfer modeling in a 1296 t/h CFB boiler with low level of flue gas recirculation

Błaszczuk A., Krzywański J.

Archives of Thermodynamics

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2017

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Vol. 38, no. 1

91--122

EN

The interrelation between fuzzy logic and cluster renewal approaches for heat transfer modeling in a circulating fluidized bed (CFB) has been established based on a local furnace data. The furnace data have been measured in a 1296 t/h CFB boiler with low level of flue gas recirculation. In the present study, the bed temperature and suspension density were treated as experimental variables along the furnace height. The measured bed temperature and suspension density were varied in the range of 1131–1156 K and 1.93–6.32 kg/m3, respectively. Using the heat transfer coefficient for commercial CFB combustor, two empirical heat transfer correlation were developed in terms of important operating parameters including bed temperature and also suspension density. The fuzzy logic results were found to be in good agreement with the corresponding experimental heat transfer data obtained based on cluster renewal approach. The predicted bed-to-wall heat transfer coefficient covered a range of 109–241 W/(m2K) and 111–240 W/(m2), for fuzzy logic and cluster renewal approach respectively. The divergence in calculated heat flux recovery along the furnace height between fuzzy logic and cluster renewal approach did not exceeded ±2%.

13

Analiza numeryczna procesu spalania w silniku HCCI z EGR zasilanym biodieslem

Jamrozik A.

Modelowanie Inżynierskie

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2016

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T. 28, nr 59

26--33

PL

Prezentowana praca zawiera wyniki modelowania w programie AVL Fire, jednocylindrowego, badawczego silnika z systemem spalania HCCI, zasilanego biodieslem - FAME. W silniku do sterowania procesem spalania zastosowano zewnętrzną recyrkulację spalin - EGR. W ramach pracy przeprowadzono badania wpływu recyrkulacji spalin na, istotne z punku widzenia pracy silnika, parametry, tj. kąt początku spalania, czas trwania spalania, ciśnienie w cylindrze i wartość ciśnienia indykowanego, szybkość wywiązywania się ciepła oraz emisje jednego z najbardziej toksycznych składników spalin - tlenku azotu. Dzięki przeprowadzonym obliczeniom można stwierdzić, że zastosowanie recyrkulacji spalin w silniku z samoczynnym zapłonem jednorodnej mieszanki biodiesla z powietrzem przyczynia się do opóźnienia początku spalania i znacznie wydłuża czas jego trwania. Wzrost opóźnienia spalania HCCI powoduje z kolei redukcję stężenia tlenku azotu w gazach wydechowych przy jednoczesnym wzroście ciśnienia indykowanego.

EN

The paper presents the CFD modelling results of the 1-cylinder HCCI test engine. Modelling was carried out using AVL Fire code. The test engine was powered by biodiesel-FAME fuel. The exhaust gas recirculation EGR used as factors of controlling the combustion process. The impact of EGR on the test engine parameters such as the start of combustion, combustion duration, in-cylinder pressure and indicated mean effective pressure, rate of heat release and NO emission were analyzed. On the basis of results stated that EGR for HCCI engine affects on the ignition delay and significantly increases the combustion duration. The increase in ignition delay of HCCI engine causes the reduction of NOx emission in exhaust gasses while increases the indicated mean effective pressure.

14

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.

15

The effect of exhaust gas recirculation on the concentration of the exhaust gas components in the diesel engine fuelled by diesel oil and FAME

Ambrozik T.

Zeszyty Naukowe Instytutu Pojazdów / Politechnika Warszawska

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2015

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z. 1/101

55--64

EN

The paper presents investigation results and the analysis of the effect of the correctly and incorrectly operating the exhaust gas recirculation system on the exhaust gas component concentrations and the excess air number. During testing, the engine was running following the idling characteristics at three crankshaft rotational speeds, i.e. 1000, 2000 and 3000 rpm. During the tests, the engine was supplied with commercial diesel oil and pure rape oil fatty acid methyl esters (FAME), respectively. The object of investigation was a self-ignition engine equipped with a common rail system and an exhaust gas recirculation system. Using an AVL DiCom 4000 exhaust gas analyzer, the concentrations of exhaust gas components, namely nitrogen oxides, hydrocarbons, carbon dioxide, carbon monoxide and oxygen, were measured. In addition, the excess air number was measured.

PL

W artykule przedstawiono wyniki badań i analizę wpływu prawidłowo i nieprawidłowo działającego układu recyrkulacji spalin na stężenia składników spalin i współczynnik nadmiaru powietrza. Podczas badań silnik pracował według charakterystyki biegu luzem i przy trzech prędkościach obrotowych wału korbowego, tj. 1000, 2000 i 3000 obr/min. Podczas badań silnik zasilany był handlowym olejem napędowym i czystymi estrami metylowymi kwasów tłuszczowych oleju rzepakowego FAME. Obiektem badań był silnik o zapłonie samoczynnym wyposażony w system common rail i układ recyrkulacji spalin. Przy pomocy analizatora spalin AVL DiCom 4000 mierzono stężenia następujących składników spalin: tlenków azotu, węglowodorów, dwutlenku węgla, tlenku węgla i tlenu. Ponadto mierzono współczynnik nadmiaru powietrza.

16

Wpływ parametrów procesu odsiarczania spalin metodą mokrą na jego efektywność

Walendziewski J., Kułażyński M., Łużny R., Solich B., Trawczyński J.

Przemysł Chemiczny

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2015

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T. 94, nr 7

1175-1178

PL

Recyrkulacja spalin może potencjalnie być stosowana jako metoda zwiększenia efektywności ich odsiarczania. W pracy przedstawiono wyniki symulacji odsiarczania spalin metodą mokrą wapienną przy zastosowaniu recyklowania (zawracania) części spalin odsiarczonych i ich wprowadzania do strumienia spalin nieodsiarczonych. Zgodnie z przewidywaniami uzyskano obniżenie temperatury i zawartości SO₂ w spalinach na wlocie do absorbera. Stwierdzono także, że zwiększenie efektywności procesu jest niewielkie, rzędu 1%. Znaczne zwiększenie masy spalin wprowadzanych do absorbera w procesie z ich recyklem powoduje, że metoda może być stosowana tylko w przypadku gdy instalacja odsiarczania spalin dysponuje nadmiarem wydajności wentylatorów. Jak wynika z wyników symulacji i uzyskanych danych przemysłowych efektywność recyklowania spalin jest ograniczona. Znacznie lepsze efekty uzyskuje się, stosując większą liczbę stopni (poziomów) zraszania spalin.

EN

The impact of recycling portion of the desulfurized gas stream and the amt. of spray levels used in the absorber on the flue gas desulfurization efficiency was simulated. The recycling a part of the desulfurized stream gas resulted in increasing the efficiency of the process by approx. 1%, while the gas recycle, together with an increased no. of spray levels resulted in increasing the efficiency of gas purifn. by approx. 4%.

17

Efekty zewnętrznej recyrkulacji spalin w systemie grzewczym baterii koksowniczej o wysokości komór 5,5 m (w ramach programu RNCF)

Hummer W., Wojciechowski G., Ziółkowska A., Szlęk A.

Karbo

|

2015

|

Nr 4

132--138

PL

Na terenie koksowni Przyjaźń powstała doświadczalna instalacja zewnętrznej recyrkulacji spalin w ramach projektu dofinansowanego przez Fundusz Badawczy Węgla i Stali pod tytułem „Minimalizacja emisji tlenków azotu poprzez usprawnienie pionowego rozkładu ciepła w kanałach grzewczych.” realizowanego przez Koksoprojekt wraz z Centre de Pyrolyse de Marienau oraz AM Maizières Research i AM Atlantique et Lorraine (umowa nr RFCR-CT-2012-00005). Instalacja umożliwia zawracanie spalin z kanału spalinowego do powietrza zasilającego kanały grzewcze. W trakcie pracy instalacji prowadzone były pomiary parametrów pracy kanałów grzewczych i komór koksowniczych. Badania wykazały, że recyrkulacja spalin do powietrza wpływa na obniżenie maksymalnej temperatury i wyrównanie rozkładów temperatur wzdłuż wysokości ściany grzewczej. Obniżenie maksymalnej temperatury i wyrównanie równomierności nagrzewania pozwala na obniżenie emisji NOX przy zachowaniu odpowiednich temperatur w komorze koksowniczej. Technologia ta dedykowana jest dla istniejących już baterii oraz dla tych nowo projektowanych, pozwala ona zmniejszyć ich uciążliwość dla środowiska i poprawić równomierność nagrzewania ścian grzewczych.

EN

Experimental installation of external flue gas recirculation was built in the coke plant Przyjaźń within a project financed by the Research Fund for Coal and Steel under the title "Nitrogen oxides emissions minimization through improvement of vertical heat distribution inside heating flues" carried on by Koksoprojekt together with the Centre de pyrolysis de Marienau and AM Maizières Research and AM Atlantique et Lorraine (contract no RFCR-CT-2012-00005). The system re-circulates flue gas from the damper near stack to the heating flues air supply. During the installation operation measurements of operating parameters of heating flues and coking chambers were carried out. It was shown that external flue gas recirculation lowers the maximum temperature and levels the temperature distribution along the height of the heating wall. Reducing the maximum temperature and improve the uniformity of the heating wall temperature reduces NOX emissions while maintaining appropriate temperatures in the coking chamber. Technology is dedicated to existing batteries and for those newly designed; it allows to reduce their environmental performance and to improve the uniformity of the flues heating.

18

Procesy szybkozmienne w cylindrze silnika ZS w warunkach dużego udziału recyrkulowanych spalin

Pielecha I., Borowski P., Wisłocki K., Skowron M., Bueschke W., Cieślik W.

Combustion Engines

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2015

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R. 54, nr 3

316--326

PL

Celem prowadzonych badań była termodynamiczna identyfikacja procesu spalania zachodzącego w silniku o zapłonie samoczynnym przy udziale recyrkulowanych spalin do 50–60%. Wartości odpowiednich wskaźników uzyskane przy dużym udziale spalin w cylindrze porównywano do wartości uzyskiwanych w silniku pracującym bez recyrkulacji. Badania przeprowadzono na jednocylindrowym silniku AVL 5804 wyposażonym w układ chłodzenia recyrkulowanych spalin. Warunki procesu spalania określano wykorzystując wskaźniki pracy silnika i pomiary szybkozmiennego ciśnienia w cylindrze. Dokonano oceny wpływu różnego udziału tych spalin w cylindrze silnika na przebieg procesu spalania oraz wywiązywania ciepła. W wyniku przeprowadzonych badań wykazano możliwość zastosowania dużej ilości recyrkulowanych spalin (50–60%) bez istotnego pogorszenia warunków pracy silnika, przy jednoczesnej poprawie wskaźników ekologicznych, nie tylko w odniesieniu do emisji tlenków azotu.

EN

The aim of the conducted research was thermodynamic identification of combustion process with 50-60% recirculated exhaust gasses in spark ignition engine. The values of the respective indicators obtained with high share of exhaust gasses in cylinder were compared to values obtained in the engine working without recirculation. The research was conducted on one-cylinder engine AVL 5804 equipped with recirculated gasses cooling system. The conditions of combustion process were determined using indicators of engine work and fast-variable measurements of cylinder pressure. The evaluation of combustion process and heat release with different share of recirculated gasses was made determining the effect of high share of exhaust gasses in engine cylinder. As a result of the conducted research the possibility of exhaust gasses high share(50–60%) usage with simultaneous ecological benefits, not only inrelation to nitrogen oxides was demonstrated.

19

Koncepcja systemu spalania z wykorzystaniem recyrkulowanych spalin w silniku o zapłonie iskrowym

Cieślik W., Pielecha I., Kapusta Ł.

Combustion Engines

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2015

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R. 54, nr 3

257--263

PL

Układy recyrkulacji spalin w silnikach o zapłonie samoczynnym są stosowane głównie w celu ograniczenia emisji tlenków azotu, a w silnikach o zapłonie iskrowym mogą być sposobem zmniejszenia zużycia paliwa. Maksymalna wielkość objętościowego udziału recyrkulowanych spalin w silnikach o zapłonie samoczynnym wynosi około 50%. W silnikach o zapłonie iskrowym udział recyrkulowanych spalin jest znacznie mniejszy. Celem artykułu jest symulacyjna analiza sposobów dostarczenia spalin do wnętrza cylindra układu o zapłonie iskrowym w celu uzyskania zapalnej mieszanki. Problemem, który starano się rozwiązać był dobór sposobu dostarczania powietrza i gazów spalinowych w celu uzyskania pożądanego przestrzennego rozkładu powietrza i spalin w cylindrze. Analizy symulacyjne prowadzono z wykorzystaniem pakietu symulacyjnego AVL Fire. Badania dotyczyły trzech wariantów dostarczenia spalin do cylindra, które cechują się odmiennym sposobem tworzenia mieszaniny gazy palne-gazy niepalne. Wyniki badań dotyczące różnych strategii wprowadzenia gazów do komory spalania rozważano pod kątem możliwości inicjowania i przebiegu procesu spalania. Podsumowaniem artykułu jest wybór strategii dostarczania spalin do cylindra silnika. W dalszych etapach prac przewiduje się adaptację badań symulacyjnych na maszynie pojedynczego cyklu.

EN

The system of exhaust gas recirculation in compression ignition engines is used to reduce the emission of nitrogen oxides, and in spark ignition engines it can be used to reduce the fuel consumption. The maximum value of the volumetric recirculation of exhaust gases in compression ignition engine amounts to approximately 50%. In spark ignition engines the share of recirculated exhaust gases is much smaller. The aim of the article is to simulation analysis of the ways of supplying exhaust gases into the cylinder of the spark ignition system in order to obtain a combustible mixture. The problem, which was to be solved, was the method of supplying the air and exhaust gases in order to obtain the required spacial distribution of the air and exhaust gases in a cylinder. The simulation analysis was conducted with the use of AVL Fire simulation package. Tests concerned three methods of supplying exhaust gases into the cylinder, which are characterised by different way of generating the mixture of flammable and inflammable gases. Test results for the different strategies of introducing gases into the combustion chamber were considered in the aspect of the possibility of initiating and the course of combustion process. The summary of the article is the choice of the strategy of supplying the exhaust gases into the cylinder. The adaptation of the simulation tests will be conducted on the Rapid Compression Machine.

20

Effect of flue gas recirculation on heat transfer in a supercritical circulating fluidized bed combustor

Błaszczuk A.

Archives of Thermodynamics

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2015

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Vol. 36, no. 3

61--83

EN

This paper focuses on assessment of the effect of flue gas recirculation (FGR) on heat transfer behavior in 1296t/h supercritical coal-fired circulating fluidized bed (CFB) combustor. The performance test in supercritical CFB combustor with capacity 966 MWth was performed with the low level of flue gas recirculation rate 6.9% into furnace chamber, for 80% unit load at the bed pressure of 7.7 kPa and the ratio of secondary air to the primary air SA/PA = 0.33. Heat transfer behavior in a supercritical CFB furnace between the active heat transfer surfaces (membrane wall and superheater) and bed material has been analyzed for Geldart B particle with Sauter mean diameters of 0.219 and 0.246 mm. Bed material used in the heat transfer experiments had particle density of 2700 kg/m3. A mechanistic heat transfer model based on cluster renewal approach was used in this work. A heat transfer analysis of CFB combustion system with detailed consideration of bed-to-wall heat transfer coefficient distributions along furnace height is investigated. Heat transfer data for FGR test were compared with the data obtained for representative conditions without recycled flue gases back to the furnace through star-up burners.