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Journal of Power Sources | 2003

Mixture preparation by cool flames for diesel-reforming technologies

L. Hartmann; Klaus Lucka; Heinrich Köhne

Abstract The separation of the evaporation from the high-temperature reaction zone is crucial for the reforming process. Unfavorable mixtures of liquid fuels, water and air lead to degradation by local hot spots in the sensitive catalysts and formation of unwanted by-products in the reformer. Furthermore, the evaporator has to work with dynamic changes in the heat transfer, residence times and educt compositions. By using exothermal pre-reactions in the form of cool flames it is possible to realize a complete and residue-free evaporation of liquid hydrocarbon mixtures. The conditions whether cool flames can be stabilised or not is related to the heat release of the pre-reactions in comparison to the heat losses of the system. Examinations were conducted in a flow reactor at atmospheric pressure and changing residence times to investigate the conditions under which stable cool flame operation is possible and auto-ignition or quenching occurs. An energy balance of the evaporator should deliver the values of heat release by cool flames in comparison to the heat losses of the system. The cool flame evaporation is applied in the design of several diesel-reforming processes (thermal and catalytic partial oxidation, autothermal reforming) with different demands in the heat management and operation range (air ratio λ , steam-to-carbon ratio, SCR). The results are discussed at the end of this paper.


Journal of Fuel Cell Science and Technology | 2008

Diesel Steam Reforming for PEM Fuel Cells

Christian Mengel; Martin Konrad; Roland Wruck; Klaus Lucka; Heinrich Köhne

Different applications for the decentralized stationary or mobile power supply require the usage of liquid hydrocarbons such as fuel oil, diesel, or gas oil in fuel cell systems. Reducing the sulfur content of conventional liquid fuels such as diesel or gasoline below 10 ppm, the usage of these fuels in fuel cell applications becomes increasingly promising. The first process step represents thereby the reforming, which can be carried out in different ways. One of the commonly favored gas process technologies is the steam reforming process, which is state of the art for natural gas applications. Using a proton exchange membrane (PEM) fuel cell requires a complex gas cleanup system. Using a pressurized steam reforming process offers a significant reduction of the whole system size by efficiently compressing the liquid educts. Complete PEM systems with steam reformers tend to have a higher efficiency than, for example, systems using the autothermal reforming process. Advanced diesel steam reformers for industrialization still have to be developed and improved. The Oel-Warme-lnstitut gGmbH has successfully carried out research on steam reforming with variations of important parameters using a sulfur free reference fuel and desulfurized diesel. During the experiments, several parameters such as steam to carbon ratio, reformer inlet temperatures, catalysts, and fuels were varied. While running the process, a continuous product gas measurement was taken. The reformer is equipped with several thermocouples. Three of them are moveable to measure the temperature profile of the catalyst. The experiments show that product gas concentrations reach a nearly equilibrium concentration with reformer inlet temperatures ϑ >700°C of a reference fuel/steam mixture. Hydrogen concentrations over 70% were feasible. Constant inlet temperatures of ϑ=850°C and a variation of the steam to carbon ratio only have a noticeable effect on the water gas shift equilibrium. After all experiments, carbon deposits were found in the steam reformer system and under some circumstances on the catalysts. Experiments with operating times of more than 20 h were performed at a steam to carbon ratio of 4.5. The application of continuously desulfurized diesel fuel indicates a degradation of the catalyst after a few hours. For the overall system design of PEM fuel cell applications, an operation mode at a reduced steam to carbon ratio bas to be developed [DOL: 10.1115/15/1.2784313] carbon ratio has to be developed.


MTZ - Motortechnische Zeitschrift | 2006

Potenzial der Kalte-Flammen-Technologie zur Darstellung der vorgemischten, homogenen Verbrennung in einem Dieselmotor

Ansgar Sommer; Heike Puschmann; Heide Pohland vom Schloß; Klaus Lucka; Heinrich Köhne

Die IAV GmbH entwickelt im Rahmen des Projekts Advanced Diesel Combustion System (ADCS) das Dieselbrennverfahren weiter. Ziel ist die innermotorische Senkung der Emissionen und eine Verbesserung des Gerauschs bei konstantem Kraftstoffverbrauch. In Kooperation mit dem Oel-Warme-Institut (OWI) wurde eine Potenzialuntersuchung zur externen Vormischung von Dieselkraftstoff und Luft durchgefuhrt.


Progress in Computational Fluid Dynamics | 2005

CFD modelling of a radiant tube burner for liquid and gaseous fuels

Frank Kleine Jäger; Jan Mevissen; Andreas Munko; Heinrich Köhne

In addition to the development of a radiant tube burner, numerical simulations were carried out at the Department of Heat and Mass Transfer (EST), RWTH Aachen (Germany), with the aim of increasing the process knowledge of the combustion concept and to optimise the burner operation. The capacity range of the burner is 20–40 kW (70,000–1,40,000 btu/hr), as combustible fuel oil and gas is used. The radiant tube burner was developed for high temperature applications and investigated at furnace temperatures of 1,000°C (1,830°F). Despite of the fact that the combustion air was preheated to a temperature of 850°C (1,560°F), extremely low emissions were achieved even when fuel oil is used as combustible. At a firing rate of 39 kW (1,33,000 btu/hr), the NOx emissions were at approx. 100 ppm (3%O2/fuel oilζN,Fuel = 140 mgNFuel


International Research of BrenaRo Winterschool | 2015

Feasibility Study of Auto Thermal Reforming of Biogas for HT PEM Fuel Cell Applications

Nan Kishore Nalluraya; Heinrich Köhne; Stephan Köhne; Martin Konrad

Biogas is easily transportable, storable and CO2 neutral. The scope of this work is to show the feasibility of H2 production through Auto Thermal Reforming (ATR) of biogas and its utilisation in High Temperature Proton Exchange Membrane Fuel Cell (HT-PEM FC) application. In this study, a fuel cell system was modelled and simulated using MATLAB/Simulink to find the feasibility of biogas reforming for High Temperature Proton Exchange Membrane (HT PEM) Fuel Cell Application. The main criteria considered are high yield of H2 and lowest possible CO. The optimum temperature, Steam to Carbon Ratio (SCR), Air-Fuel Ratio (AFR), and reforming temperature were found out with the help of simulation. A test reference 5 kWth Auto Thermal Reformer (ATR) with Water Gas Shift (WGS) reactor was built according to the simulation guidelines in order to produce H2 to feed a 1 kWel HT-PEM Fuel Cell with anode gas. The reliability and the durability of the system were tested with a start-and-stop strategy and a continuous mode respectively. The electrical efficiency of the whole Fuel Cell system was simulated to around 30 %. The experimental work validated the simulation results within acceptable margins. The experimental study shows that it is not only feasible to produce on-board H2 with biogas but also that the start-and-stop mode of operation does not damage the fuel cell which makes it even suitable for automotive application.


MTZ worldwide | 2006

Potential of cool flame technology to realize premixed, homogeneous combustion in a diesel engine

Ansgar Sommer; Heike Puschmann; Heide Pohland vom Schloß; Klaus Lucka; Heinrich Köhne

To advance the diesel combustion process, a Cool Flame Vaporizer produced at OWI (Oel-Warme-Institut) was modified for use on a passenger car diesel engine. For test bench experiments IAV GmbH adapted the vaporizer to a single-cylinder test engine for external mixture preparation. The engine was run with the vaporizer in different operating states and the results were compared with conventional DI diesel combustion as well as DI premixed combustion with early homogenization (PCCI).


Progress in Computational Fluid Dynamics | 2003

Application of CFD in the development of process burner technology for the combustion of light residual fuel oils

Frank Kleine Jäger; Yiming Wu; Jiaosuo Zhang; Heinrich Köhne

Since June 1999, work has been continued on behalf of the OMV AG Vienna for a consistent development of Low- NOx-concepts for the combustible fuel oil light also for higher burner outputs. Together with the MAX WEISHAUPT GmbH, a leading company in fuel engineering, the OMV AG has therefore initiated a project, the aim of which is the development of a Low- NOx-mixing device in the capacity range 500 kW-3 MW. The aim of this project, carried out at the Oel-Warme-Institut (OWI) in Aachen, is to allow also for the recently developed burner, beside minimal CO and soot emissions (CO < 20 mg/m? RZ < 1), a NOx-emission below 400 mg/m?. With a design capacity of 500 kW and 1.2 MW, the construction sizes I and II of the new development project for the moment are on the test stand - the measured NOx-emissions show that a high NOx-reduction potential exists and the corresponding project aims can be fulfilled. By means of several CFD investigations of the present combustion system with the software code CFX the phenomena, important for the practice, could be verified and the understanding of these phenomena substantially be improved.


Archive | 1999

Flüssige Brennstoffe im Kommen

Heinrich Köhne; Heinz-Peter Gitzinger; Klaus Lucka

Alle modernen Verbrennungsverfahren haben ein gemeinsames Konstruktionsmerkmal: Eine ausgeklugelte Technik bereitet aus dem gasformigen, flussigen oder festen Brennstoff und der Luft ein zundfahiges Gemisch. Die Gemischbildung stellt ein entscheidendes Kriterium fur die Qualitat der Verbrennung dar. Bei Inhomogenitaten, gleich welcher Art, bilden sich verstarkt Schadstoffe. So treten bei Mangel an Sauerstoff im Abgas mehr unverbrannte Kohlenwasser-stoffe und Rus auf. Zugleich steigt die Verbrennungstemperatur, aus dem Luftstickstoff und dem Sauerstoff entstehen zusatzlich schadliche Stickoxide.


Fuel | 2008

Selective removal of sulphur in liquid fuels for fuel cell applications

Oliver van Rheinberg; Klaus Lucka; Heinrich Köhne; Thomas Schade; Jan T. Andersson


Proceedings of the Combustion Institute | 2007

Low temperature oxidation of diesel–air mixtures at atmospheric pressure

Ralph Edenhofer; Klaus Lucka; Heinrich Köhne

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Klaus Lucka

RWTH Aachen University

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Antonio Delgado

University of Erlangen-Nuremberg

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