Hartmut Krause

Technische Universität Bergakademie Freiberg · Institute of Thermodynamics and Thermal Engineering

The combustion properties of hydrogen-containing fuel mixtures and the effect of the variation of the oxygen content of the oxidizer are at the center of recent research interest. Laminar burning velocity measurements with varied oxygen content can help in the validation of reaction mechanisms for better simulations of combustion systems using exha...

Thermal utilization of hydrogen is becoming increasingly important as the climate change progresses. Fossil fuels such as natural gas are replaced by green hydrogen in the natural gas grid to reduce CO 2 emissions. However, the switch to hydrogen causes significant changes in combustion properties, such as higher flame temperatures or higher burnin...

The present work reports experimentation and numerical simulations of laminar burning velocity, emission analysis, and flame structure of dimethyl ether-hydrogen mixtures. The volumetric hydrogen addition is considered into the DME fuel for a range of mixture equivalence ratios (0.6< f < 1.7). The initial mixture temperature is raised to 373 K at c...

The introduction of other combustible gases to methane could change accident consequences. This work aimed to experimentally compare the effects of blended fuels (C2H6, C2H4 , CO, and H2 mix in different proportions) on the explosion pressure behavior of methane and blended fuels in air. The explosion pressure properties of the mixtures were tested...

This work focuses on hydroxyl (OH) radical formation in methane flames with varying hydrogen admixtures as an indicator of changing reaction kinetics and resulting flame front position. Therefore, quantitative OH-PLIF measurements were performed using a Nd:YAG pumped dye laser with a McKenna burner as a calibration target. To demonstrate the reliab...

This work focuses on hydroxyl (OH) radical formation in methane flames with varying hydrogen admixtures as an indicator of changing reaction kinetics and resulting flame front position. Therefore, quantitative OH-PLIF measurements were performed using a Nd:YAG pumped dye laser with a McKenna burner as a calibration target. In general, the results o...

In this work, the influence of H2 addition on the auto-ignition and combustion properties of CH4 is investigated experimentally and numerically. Experimental ignition delay times (IDT) are compared with simulations and laminar burning velocities (LBVs), and extinction limits/extinction strain rates (ESRs) are compared with data from the literature....

Investigations into the combustion characteristics and flame structure of hydrogen/carbon dioxide/air flames have been carried out experimentally and numerically. The aim was to determine the variations of the combustion properties and flame shape for different carbon dioxide dilutions in the H2-air mixtures. For this purpose, premixed flames at va...

This contribution presents a novel pilot plant for advanced combustion research to address current issues related to the conversion from conventional to renewable fuels. It consists of an optically accessible combustion chamber and a Nd:YAG-Dye-Laser-System, which allows a wide range of measurements within the flame, e.g. distribution of NO/OH/CH s...

Microwaves can interact with the flame’s combustion zone and increase the energy density. This induces changes to the combustion properties by influencing the radical formation and significantly expanding the flame thickness. It is possible to combust low calorific gas mixtures in a stable process without preheating or co-firing with microwave assi...

Chemical reaction mechanisms with detailed kinetics are an important topic in combustion science and an essential prerequisite for the accurate modeling of reactive flows in combustors. Besides isolating and studying individual reactions, the development of reaction mechanisms is often based on well-defined experimental observables, such as the lam...

Supplementary to manuscript: Combined experimental and numerical study on the extinction limits of non-premixed H2/CH4 counterflow flames with varying oxidizer composition

Biodiesel is a family of renewable engine fuels with carbon-neutral nature. In this work, three C5H10O2 esters (methyl butanoate, methyl isobutanoate and ethyl propanoate), which can serve as model compounds of biodiesel and represent linear and branched methyl esters and linear ethyl esters, were investigated to characterize their laminar flame pr...

This work reports on the development and experimental validation of a detailed reaction mechanism for the oxidation of polyoxymethylene dimethyl ethers (OMEn, n = 1-3). The validation is done by constant-volume chamber laminar flame speeds (393 K and 443 K, 1 to 5 bar, and equivalence ratio 0.8 to 1.6) and Rapid Compression Machine ignition delay t...

Reactivity controlled compression ignition (RCCI) engine is a dual fuel strategy that uses fuels with different reactivities. In this study, Hythane or HCNG (60% methane and 40% hydrogen) as a low reactivity fuel and diesel or OME with high reactivity are used. Thus, Hythane consists 5% of the incoming air mass, and OME/diesel is sprayed under full...

The utilization of hydrogen in combustion processes and the associated changes in the combustion characteristics are increasingly of interest to the industry. Especially the combustion of methane-hydrogen-oxygen mixtures as well as pure hydrogen-oxyfuel mixtures for low-emission combustion systems have been less investigated. In this work, hydrogen...

This work aimed to experimentally compare the effects of blended fuels (C2H6, C2H4, CO, and H2 mix in different proportions) on the explosion pressure behavior of methane and blended fuels in air. The explosion pressure properties of the mixtures were tested in a spherical 20 L gas explosion tank at ambient temperature. Principal component analysis...

The usage of artificial intelligence (AI) is increasing in many fields of research, since complex physical problems can be ‘learned’ and reproduced by AI methods. Thus, instead of numerically solving partial differential equations, describing the physical processes in detail, appropriate AI methods can be used to decrease the calculation time signi...

The use of oxymethylene ethers (OMEs) as alternative fuels or fuel-additives has motivated the present study on the combustion behavior of trimethoxy methane (TMM), which is a branched version of OMEs. A detailed chemical kinetic model for TMM combustion is provided, which is based on a recent model for the structurally similar dimethoxy methane (D...

The generation of renewable energy through carbon-neutral fuels has been initiated by several international institutions. Hydrogen, ammonia and bio-methane are considered the available and most potential solutions for this transfer. However, the technologies for its reliable storage and optimized combustion are still under development or in the pro...

The generation of renewable energy through carbon-neutral fuels has been initiated by several international institutions. Hydrogen, ammonia and bio-methane are considered the available and most potential solutions for this transfer. However, the technologies for its reliable storage and optimized combustion are still under development or in the pro...

The production of carbon-neutral fuels through clean energy has been defined as a target by the European Union and by several international institutions. If the concepts are available, hydrogen, in particular, is considered to be one of the most target-oriented, ecologically and economically realizable approaches. In terms of safety, long-time stor...

The production of clean energy via carbon-neutral fuels has been included in a road map within several international institutions. Among the available alternatives, hydrogen has been largely considered as one of the most promising solutions. However, technologies for its safe storage and optimized combustion are still under development or on a prot...

In the present discussion of transition the energy supply and sector coupling processes, hydrogen and hydrogen / natural gas mixtures will play an important role in future gas usage as gaseous energy carrier mainly natural gas is widely used in industrial combustion systems, combustion engines as well as domestic heating systems. Combustion propert...

In times of increasing global warming, enormous efforts are required to rapidly reduce greenhouse gas (GHG) emissions. In Germany the industry is one of the largest GHG emitting sectors and process heat supply is mainly covered by the combustion of fossil fuels [1]. Due to the EU's target of climate neutrality by 2050 and the even more ambitious go...

The aim of the present work is to contribute to the better understanding of the combustion process and the laminar flame properties of methane/hydrogen-air flames at elevated temperatures and pressures. The heat flux method provides an accurate and direct measurement of laminar burning velocities (LBV) at elevated temperatures, while the constant v...

Historically, scale‐up of technologies have been a fundamental driver for successful economies in enhancing performance of applications. In the context of combustion technologies, several scale‐up approaches were developed with the aim of transferring relevant characteristics of combustion systems from laboratory‐ to industrial‐scale system. A reas...

In times of increasing global warming, enormous efforts are required to rapidly reduce greenhouse gas (GHG) emissions. Industry is one of the largest GHG emitting sectors and process heat supply is so far almost exclusively based on the combustion of fossil fuels. Due to the EU's target of climate neutrality by 2050, it is necessary to systematical...

The aim of this work is to contribute to the better understanding of the oxidation process of light hydrocarbons, low calorific value gas and components of natural gas in the presence of inert gases and the influence of oxygen reduction in exhaust gas recirculation situations. The extinction behavior of laminar counterflow diffusion flames of metha...

Polyoxymethylene dimethyl ethers (OMEn) with the chemical structure of CH3O(CH2O)nCH3 are a promising synthetic e-fuel class that can be produced from renewable electricity and improves the emission characteristics of internal combustion engines. However, knowledge of their fundamental combustion properties, such as the laminar burning velocity, is...

Iron oxides are useful adsorbents for the alternating removal of H2S and O2 from natural gas and biogas. In this context, the present paper aims to elucidate the mechanisms behind the consecutive adsorption of both gases. Three different types of iron oxides/hydroxides were investigated using in-situ infrared and Raman spectroscopy as well as ex-si...

In dieser Arbeit wird ein in der Entwicklung befindliches Messsystem vorgestellt, mit welchem eine bildgebende Echtzeitüberwachung des lasergestützten Abtrages von organischen Beschichtungen von Betonoberflächen ermöglicht wird. Das Verfahren wird im Rahmen eines FORKA - Projektes des BMBF entwickelt, bei welchem eine laserbasierte Dekontaminations...

This contribution presents a novel pilot plant for advanced combustion research to address current issues related to the conversion from conventional to renewable fuels. It consists of an optically accessible combustion chamber and a Nd:YAG-Dye-Laser-System, which allows a wide range of measurements within the flame, e.g. distribution of NO/OH/CH s...

The laminar burning velocity (LBV), extinction limits and strain rate (ESR) are fundamental property of a reactive fuel-oxidizer mixture, varying with composition, pressure and initial temperature. These values are important for validation of reaction mechanisms and the specific design of industrial burners. Particularly, there is a lack of accurat...

In this poster an experimental methodology on a laboratory scale is presented. The setup will be used to investigate the thermal decomposition of organic coatings or resins. The method is being developed as part of “LaDECO”, a FORKA project of the Federal Ministry of Education and Research Germany, in which a laser-based decontamination technology...

In this paper a methodology on a laboratory scale is presented. The setup will be used to investigate the thermal decomposition of organic coatings or resins. The method is being developed as part of “LaDECO”, a FORKA project of the Federal Ministry of Education and Research, in which a laser-based decontamination technology is qualified for usage...

Due to increasing requirements in combustion technology, multi-stage combustion systems are increasingly used in industry. In terms of changing gas qualities, e.g. the use of hydrogen and the simultaneous effort to reduce pollutants with the focus on minimizing nitrogen oxide, knowledge of the processes in large scale combustion systems becomes mor...

This work reports the laminar burning velocities for CH4/H2 blends in mixtures with air utilizing the constant volume chamber at temperatures from 300 to 423 K, pressures from 2 to 10 bar and equivalence ratios from 0.7 to 2.4. A detailed chemical kinetic model based on our previous work is used to reproduce the experimental data. The chemical kine...

This work reports the laminar burning velocities (LBV) for the liquid fuels methanol, and polyoxymethylene dimethyl ethers (OMEn, n = 1-3) in mixtures with air utilizing the heat flux burner and constant volume chamber at temperature 393 to 443 K, pressure 1 to 10 bar, and equivalence ratio 0.6 to 1.9. Laminar burning velocities for OME2 and OME3 h...

The aim of this work is to contribute to a better understanding of the oxidation characteristics of light C2 hydrocarbons (C2H2 , C2H4 , C2H6) in interaction with inert gases and the influence of oxygen reduction for example in exhaust gas recirculation and staged combustion situations. For these gas mixtures, the extinction strain rates (ESR) and...

This work presents a simultaneous approach for the integration of thermal energy storage (TES) into multiperiod heat integration problems by combining mathematical optimisation and Pinch Analysis. This approach is an adaption of the linear programming (LP) model according to Cerda et al. [2] and was adapted for multiperiod problems according to Ayd...

The laminar burning velocity is a fundamental property of a reactive fuel-oxidizer mixture, varying with composition, pressure, and initial temperature. These values are important for validation of reaction mechanisms and the specific design of industrial burners in general, and, with the main aim of this study, for the usage of different hydrogen...

Extinction distance of fuel gases is a design parameter for safety devices in burners and for flame barriers in ATEX systems. In the present work, a method for determination of extinction distance of fuel gases for temperatures up to 573 K and typical combustion related air ratios is being developed. In this innovative approach, a special designed...

This publication presents a novel pilot plant for advanced combustion research to address current issues related to the conversion from conventional to renewable fuels. It consists of an optically accessible combustion chamber and a Nd:YAG-Dye-Laser-System, which allows a wide range of measurements within the flame, e.g. distribution of NO/OH/CH sp...

Polyoxymethylene dimethyl ethers (OMEn) with the chemical structure of CH3O(CH2O)nCH3 are a promising synthetic e-fuel class that can be produced from renewable electricity and improves the emission characteristics of internal combustion engines. However, knowledge of their fundamental combustion properties, such as laminar burning velocity, is lim...

Premixed flames play a prominent role in combustion systems such as aircraft combustors, gas turbines and internal combustion engines. Current fuels are also derived from fossil sources, including coal, petrol, gasoline, natural gas or liquefied petroleum gas. Alternatively, liquid and gaseous biofuels, such as eth-anol and biodiesel, hydrogen, woo...

Laminar flame propagation was investigated for pentanone isomers/air mixtures (3-pentanone, 2-pentanone and 3-methyl-2-butanone) in a high-pressure constant-volume cylindrical combustion vessel at 393–423 K, 1–10 atm and equivalence ratios of 0.6–1.5, and in a heat flux burner at 393 K, 1 atm and equivalence ratios of 0.6–1.5. Two kinds of methods...

Laminar flame speeds of dimethyl ether and dimethoxymethane at pressures from 1 to 5 bar and initial temperatures from 298 to 373 K were determined experimentally using a constant volume spherical vessel and a heat flux burner setup. This study is the first to report dimethoxymethane laminar flame speeds at a pressure higher than 1 bar. Using these...

Knapp 67 % des Endenergiebedarfs der Deutschen Industrie wird zur Erzeugung von Prozesswärme benötigt. Da diese derzeit fast ausschließlich durch den Einsatz fossiler Energieträger bereitgestellt wird, ist die Prozesswärmebereitstellung mit erheblichen CO2-Emissionen verbunden. Bis zum Jahr 2050 soll auch die Industrie nahezu Klimaneutralität errei...

In dieser Arbeit wurden die Erlöschungsstreckungsraten von laminaren nicht vorgemischten Flammen und die laminare Brenngeschwindigkeit (LBV) von vorgemischten Methan- und Wasserstoffflammen untersucht. Ziel der Arbeit ist ein besseres Verständnis der Brennstoffkomponenten im Zusammenspiel mit Inertgasen und sauerstoffreduzierter Luft. Für diese Gas...

Germanium- (Ge) und Seltene Erden (SE) sind sehr wertvolle Rohstoffe. Die Nachfrage der Industrie steigt stetig, da diese Rohstoffe vor allem in der Mikroelektronik eingesetzt werden. Ein vielversprechender Weg, die Versorgung mit diesen Elementen zu verbessern, ist das Phytomining. Mit Phalaris arundinacea (Rohrglanzgras) besteht die Möglichkeit,...

Low laminar burning velocity’s and slow reactions propagation are among a key problem in combustion processes with low calorific gas mixtures. The mixtures have a laminar burning velocity of 10 cm/s to 15 cm/s or even below which is 37% of natural gas. Thermal use of these gases could save considerable amounts of fossil fuel and reduce CO2 emission...

In this paper the extinction behavior of laminar non-premixed and the laminar burning velocity (LBV) of premixed methane and hydrogen flames are evaluated. The aim of the work is a better understanding of fuel components in interaction with inert gases and oxygen reduced air. For these gas mixtures, the extinction rates and LBV as two important phy...

The laminar burning velocity, extinction limits and strain rate are fundamental property of a reactive fuel-oxidizer mixture, varying with composition, pressure and initial temperature. These values are important for validation of reaction mechanisms and the specific design of industrial burners. Particularly, there is a lack of data of different h...

This study deals with the development of iron oxide/hydroxide adsorbents for the alternating removal of H 2 S and O 2 from natural gas and biogas. The considered procedure initially implies the chemisorption of H 2 S. In the second step, O 2 is removed by reaction with the H 2 S-treated substrate accompanied by regeneration of the adsorbent. 35 dif...

2016 war erneut ein Jahr voller Herausforderungen für die Gaswirtschaft: Der Klimaschutzplan 2050, der Pariser Klimagipfel COP21 und das EU-Winterpaket haben dem Energieträger Gas neue Leitplanken aufgezeigt. Positive Impulse setzte der Strommarkt mit einer verbesserten Auslastung der Gaskraftwerke. Verflüssigtes Erdgas (LNG) wird zunehme...

The laminar burning velocity is a fundamental property of a reactive fuel-oxidizer mixture, varying with composition, pressure and initial temperature. These values are important for validation of reaction mechanisms and the specific design of industrial burners. However, there is a lack of data for hydrogen and low oxygen combustion and moreover o...

A grid of hydrogen refuelling stations comparable to gasoline is essential for improving the individual transport based on fuel cell technology. To avoid transport and storage problems with hydrogen, small-scale hydrogen production plants are required. During the project BioRobur a pilot-plant with a hydrogen output of 50 Nm³/h was constructed and...

This work investigates the slagging behavior of miscanthus at low power burners. Different methods of slag inhibition were established and rated. Thermodynamic calculations determine the first melting of miscanthus ash to be 740 °C, equal to that of wood. But since miscanthus contains higher proportions of silica, potassium and chlorine, problems o...

Noch vor einigen Jahren wurde die deutsche Energiewende von manchen Beobachtern als „Sonderweg“ bezeichnet. Dem deutschen Beispiel werde international kaum jemand folgen, so die kritische Prognose. Zudem wurden Erdgas, erneuerbare Gase und Gasinfrastrukturen im Energie - konzept der Bundesregierung 2010 nur am Rande erwähnt. Dies hat dazu gefüh...

In this study, a robust and efficient decentralized fuel processor based on the direct autothermal reforming (ATR) of biogas with a nominal production rate of 50 Nm³/h of hydrogen and a plant efficiency of about 65% was developed and tested. The ATR unit is composed of a structured catalyst support for the biogas reforming close coupled to a cataly...

Abstract The laminar burning velocity is a fundamental property of a reactive fuel-oxidizer mixture, varying with composition, pressure and initial temperature. These values are important for validation of reaction mechanisms and the specific design of industrial burners. There are several experimental methods to measure laminar burning velocity,...

In this paper the extinction behaviour of laminar non-premixed methane and dimethylether flames is described. The aim of the work is a better understanding of fuel components in interaction with inert gases. For these gas mixtures, the extinction rates as one of the very interesting physico-chemical properties were investigated. These properties ar...

The present work deals with the modelling and simulation of a biogas Demo-processor for green hydrogen production via Autothermal reforming (ATR) process aimed at covering a wide span of potential applications, from fuel cells feed up to the production of pure hydrogen. The biogas ATR unit is composed of a structured catalyst support close coupled...

Microwave heating is a promising technology for high temperature materials processing, in particular melting of oxidic materials. The special characteristics of microwave heating and melting require refractory materials with very specific properties. The foremost important properties are microwave transparency, high thermal shock resistance as well...

In recent years, natural gas quality has become a contested topic for market partners along the gas value chain, especially in the context of the European gas quality harmonization process. While a consensus could be achieved on many aspects of gas quality regulation, leading to a first European standard for H-gas quality (EN 16726), this standard...

Industrial furnaces are analyzed continuously to identify optimization potentials. Process data from the glass industry suggest that the size of a plant has an important influence on the specific energy consumption. This leads to incorrect results when using key performance indicators (KPIs) for comparison purposes. Therefore, the evaluation of inn...

The inner walls and construction elements of industrial furnaces and boilers are undergoing a steady degradation caused by thermal and mechanical stresses as well as erosion and aging processes. This may result in efficiency losses, decreasing product quality and increasing maintenance costs. The inspection and analysis of combustion processes, tre...

The emphasis of the work was to study the influence of ethanol and n-butanol addition on soot formation in the combustion process of iso-octane. Soot particle size distribution functions were measured at different heights above the burner in selected fuel-rich atmospheric pressure laminar premixed iso-octane/ethanol and iso-octane/n-butanol flames....

In this paper the results of the operation of a pilot-plant with a hydrogen output of 50 Nm³/h are discussed. This plant shows the possibility of distributed production of hydrogen for the powertrains based on hydrogen. The focus of the investigations is the long-term behavior of the novel Nickel-based catalyst. This includes experimental studies o...