The Complex Oxidation Behavior of Pd Combustion Catalysts

2001 ◽  
Vol 7 (S2) ◽  
pp. 1064-1065
Author(s):  
K. Lester ◽  
A.K. Datye
Keyword(s):  
Phase Transformations ◽  
High Temperatures ◽  
Catalytic Combustion ◽  
Catalyst Activity ◽  
Combustion Process ◽  
Reaction Rates ◽  
Stable Operation ◽  
Temperature Combustion ◽  
High Temperature Combustion ◽  
Complex Oxidation

Combustion of natural gas for power generation leads to NOx formation due to the high temperatures encountered. Catalytic combustion allows the entire combustion process to be completed at temperatures where NOx formation can be avoided. The catalyst of choice is supported PdO. As temperature is increased, PdO decomposes to Pd metal with profound effects on catalyst reactivity. Persistent hysteresis in reaction rates have been related to the decomposition of PdO into Pd and its reformation.Understanding and controlling the phase transformations, and the resulting activity variations, is of enormous importance for high temperature combustion catalysts where predictable catalyst activity is necessary for stable operation. Farrauto et al. studied the phase transformations of PdO to Pd using thermogravimetric analysis (TGA). They concluded that while PdO decomposes to Pd at high temperatures during the heating cycle, upon cooling the Pd does not transform to PdO till the temperature drops by several hundred degrees.

scholarly journals LASER SYSTEM FOR STUDYING THE DYNAMICS OF HIGH TEMPERATURE COMBUSTION

2019 ◽  
Vol 4 (2) ◽  
pp. 154-162
Author(s):  
Lin Li ◽  
Fedor Gubarev ◽  
Andrei Mostovshchikov ◽  
Alexander Ilyin
Keyword(s):  
High Temperature ◽  
Narrow Band ◽  
Laser System ◽  
Combustion Process ◽  
Visual Observation ◽  
Copper Bromide ◽  
Temperature Combustion ◽  
Temporal And Spatial ◽  
Combustion Processes ◽  
High Temperature Combustion

The paper is devoted to development of methods for studying the dynamics of high-temperature combustion of aluminum nanopowder.The difficulty in studying the combustion of nanopowders is the high temperature and intensity of light emissionduring the combustion process, which makes the visual observation virtually impossible.The paper discusses various schemes using laser radiation to study the combustion processes of metal nanopowders.Particular mentions the use of the laser monitor based on an active medium on copper bromide vapor to study the combustion process of various powders and mixtures.The laser monitor combines the functions of the narrow-band laser illuminator and the brightness amplifier, thereby achieving the visualization at a narrow gain wavelength. Therefore, the laser monitor can be used to observe the changes in the surface of a burning sample with high temporal and spatial resolution.

New Catalytic Combustion Technology for Very Low Emissions Gas Turbines

1994 ◽  
Author(s):  
R. A. Dalla Betta ◽  
J. C. Schlatter ◽  
S. G. Nickolas ◽  
D. K. Yee ◽  
T. Shoji
Keyword(s):  
Thermal Shock ◽  
Gas Turbine ◽  
High Temperatures ◽  
Gas Turbines ◽  
Catalytic Combustion ◽  
Combustion Process ◽  
Combustion System ◽  
Gas Turbine Combustors ◽  
Homogeneous Combustion ◽  
Combustion Technology

A catalytic combustion system has been developed which feeds full fuel and air to the catalyst but avoids exposure of the catalyst to the high temperatures responsible for deactivation and thermal shock fracture of the supporting substrate. The combustion process is initiated by the catalyst and is completed by homogeneous combustion in the post catalyst region where the highest temperatures are obtained. This has been demonstrated in subscale test rigs at pressures up to 14 atmospheres and temperatures above 1300°C (2370°F). At pressures and gas linear velocities typical of gas turbine combustors, the measured emissions from the catalytic combustion system are NOx < 1 ppm, CO < 2 ppm and UHC < 2 ppm, demonstrating the capability to achieve ultra low NOx and at the same time low CO and UHC.

Effect of oxidative torrefaction on high temperature combustion process of wood sphere

Fuel ◽  
2021 ◽  
Vol 286 ◽  
pp. 119379
Author(s):  
Xin Li ◽  
Zhimin Lu ◽  
Jinzheng Chen ◽  
Xiaoxuan Chen ◽  
Yuan Jiang ◽  
...  
Keyword(s):  
High Temperature ◽  
Combustion Process ◽  
Temperature Combustion ◽  
High Temperature Combustion

Combustion Characteristics of a Helmholtz-Type Valveless Self-Excited Pulse Combustor

2013 ◽  
Vol 291-294 ◽  
pp. 1719-1722 ◽  
Author(s):  
Yu Fen Qian ◽  
Yan Ying Xu ◽  
Ti Hai Xu
Keyword(s):  
Combustion Chamber ◽  
Combustion Process ◽  
Acoustic Oscillation ◽  
Combustion Characteristics ◽  
Ignition Source ◽  
Pulse Combustor ◽  
Temperature Combustion ◽  
Pulse Combustion ◽  
Physical And Mathematical Models ◽  
High Temperature Combustion

Combustion characteristics of a Helmholtz-type valveless self-excited pulse combustor with continuous supply of gas and air were studied. The physical and mathematical models are established based on the actual pulse combustor, and the combustion characteristics are simulated with CFD. The results show that the possible re-ignition sources for the pulse combustion may be three. The first source may be the hot remnant gas near gas/air mixture. The second re-ignition source may be the high-temperature combustion chamber wall. The third ignition source is the unburned mixture. The pressure, temperature and mass fraction of propane in the combustion chamber have the phase relations and the combustion process stimulates the acoustic oscillation.

Controlling Gasoline Low Temperature Combustion by Diesel Micro Pilot Injection

2011 ◽  
Author(s):  
Johannes Eichmeier ◽  
Uwe Wagner ◽  
Ulrich Spicher
Keyword(s):  
Low Temperature ◽  
Combustion Process ◽  
Pressure Rise ◽  
Reaction Rates ◽  
Pollutant Emissions ◽  
Experimental Investigations ◽  
Injection Timing ◽  
Pilot Injection ◽  
Low Temperature Combustion ◽  
Temperature Combustion

The simultaneous reduction of fuel consumption and pollutant emissions, namely NOx and soot, is the predominant goal in modern engine development. In this context, low temperature combustion concepts are believed to be the most promising approaches to resolve the above mentioned conflict of goals. Disadvantageously these combustion concepts show high peak pressures or high rates of pressure rise due to early ignition and high reaction rates especially at high loads. Furthermore, there are still challenges in controlling combustion phasing. In this context using a small amount of pilot Diesel injected directly into the combustion chamber to ignite a highly diluted gasoline air mixture can overcome the aforementioned difficulties. As the gasoline does not ignite without the Diesel, the pilot injection timing can be used to control combustion phasing. By increasing dilution even high loads with low rates of pressure rise and without knocking are possible. This paper shows the results of experimental investigations carried out on a heavy duty boosted single cylinder Diesel engine. Based on the indicated cylinder pressure, the combustion process is characterised by performing knock analyses as well as thermodynamic analyses. Furthermore an optically accessible engine has been set up to investigate both the Diesel injection and the combustion process by means of digital high speed imaging. Together with the thermodynamic analyses the results of these optical investigations make up the base for the presented theoretical model of this combined Diesel gasoline combustion process. To show the load potential of this Dual-Fuel-CAI concept, the engine was operated at 2100 1/min with an IMEP of 19 bar. NOx emissions did not exceed 0.027 g/kWh.

Controlling Gasoline Low Temperature Combustion by Diesel Micro Pilot Injection

2012 ◽  
Vol 134 (7) ◽  
Author(s):  
Johannes Eichmeier ◽  
Uwe Wagner ◽  
Ulrich Spicher
Keyword(s):  
Low Temperature ◽  
Combustion Process ◽  
Pressure Rise ◽  
Reaction Rates ◽  
Pollutant Emissions ◽  
Experimental Investigations ◽  
Injection Timing ◽  
Pilot Injection ◽  
Low Temperature Combustion ◽  
Temperature Combustion

The simultaneous reduction of fuel consumption and pollutant emissions, namely NOx and soot, is the predominant goal in modern engine development. In this context, low temperature combustion concepts are believed to be the most promising approaches to resolve the above mentioned conflict of goals. Disadvantageously these combustion concepts show high peak pressures or high rates of pressure rise due to early ignition and high reaction rates especially at high loads. Furthermore, there are still challenges in controlling combustion phasing. In this context using a small amount of pilot diesel injected directly into the combustion chamber to ignite a highly diluted gasoline air mixture can overcome the aforementioned difficulties. As the gasoline does not ignite without the diesel, the pilot injection timing can be used to control combustion phasing. By increasing dilution even high loads with low rates of pressure rise and without knocking are possible. This paper shows the results of experimental investigations carried out on a heavy duty boosted single cylinder diesel engine. Based on the indicated cylinder pressure, the combustion process is characterized by performing knock analyses as well as thermodynamic analyses. Furthermore, an optically accessible engine has been set up to investigate both the diesel injection and the combustion process by means of digital high speed imaging. Together with the thermodynamic analyses the results of these optical investigations make up the base for the presented theoretical model of this combined diesel-gasoline combustion process. To show the load potential of this Dual-Fuel-CAI concept, the engine was operated at 2100 1/min with an IMEP of 19 bar. NOx emissions did not exceed 0.027 g/kWh.

scholarly journals Двухканальный лазерный монитор для наблюдения процессов высокотемпературного горения нанопорошков металлов

2021 ◽  
Vol 47 (7) ◽  
pp. 38
Author(s):  
Ф.А. Губарев ◽  
А.В. Мостовщиков ◽  
А.П. Ильин ◽  
Л. Ли ◽  
А.И. Федоров ◽  
...  
Keyword(s):  
High Temperature ◽  
Experimental Technique ◽  
Image Acquisition ◽  
Combustion Process ◽  
Combustion Products ◽  
The Other ◽  
Powder Materials ◽  
Digital Cameras ◽  
Temperature Combustion ◽  
High Temperature Combustion

A laser monitor with two image acquisition channels based on two brightness amplifiers and two digital cameras is presented. The laser monitor makes it possible to visualize the surface of metal nanopowders during combustion simultaneously in two regions of the sample or in one region with different magnifications. The delay between the radiation pulses of the brightness amplifiers is set in such a way that the radiation of one brightness amplifier does not affect the image formed by the other brightness amplifier. The proposed experimental technique makes it possible to study the surface of samples of powder materials during high-temperature combustion, accompanied by intense glowing and scattering of combustion products. The use of two-channel visualization makes it possible to study the surface of a burning sample in more detail, in particular, to study the inhomogeneity of the combustion process.

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