scholarly journals Assessing NO2-Hydrocarbon Interactions during Combustion of NO2/Alkane/Ar Mixtures in a Shock Tube Using CO Time Histories

Fuels ◽  
2022 ◽  
Vol 3 (1) ◽  
pp. 1-14
Author(s):  
Olivier Mathieu ◽  
Sean P. Cooper ◽  
Sulaiman A. Alturaifi ◽  
Eric L. Petersen
Keyword(s):  
Natural Gas ◽  
Shock Tube ◽  
Gas Turbines ◽  
Rate Coefficients ◽  
Combustion Chemistry ◽  
Laser Absorption ◽  
Time Histories ◽  
Reduce Emissions ◽  
Main Components ◽  
Detailed Kinetics

Modern gas turbines use combustion chemistry during the design phase to optimize their efficiency and reduce emissions of regulated pollutants such as NOx. The detailed understanding of the interactions during NOx and natural gas during combustion is therefore necessary for this optimization step. To better assess such interactions, NO2 was used as a sole oxidant during the oxidation of CH4 and C2H6 (the main components of natural gas) in a shock tube. The evolution of the CO mole fraction was followed by laser-absorption spectroscopy from dilute mixtures at around 1.2 atm. The experimental CO profiles were compared to several modern detailed kinetics mechanisms from the literature: models tuned to characterize NOx-hydrocarbons interactions, base-chemistry models (C0–C4) that contain a NOx sub-mechanism, and a nitromethane model. The comparison between the models and the experimental profiles showed that most modern NOx-hydrocarbon detailed kinetics mechanisms are not very accurate, while the base chemistry models were lacking accuracy overall as well. The nitromethane model and one hydrocarbon/NOx model were in relatively good agreement with the data over the entire range of conditions investigated, although there is still room for improvement. The numerical analysis of the results showed that while the models considered predict the same reaction pathways from the fuels to CO, they can be very inconsistent in the selection of the reaction rate coefficients. This variation is especially true for ethane, for which a larger disagreement with the data was generally observed.

CO and H2O Time-Histories in Shock-Heated Blends of Methane and Ethane for Assessment of a Chemical Kinetics Model

2017 ◽  
Vol 139 (12) ◽  
Author(s):  
O. Mathieu ◽  
C. R. Mulvihill ◽  
E. L. Petersen ◽  
Y. Zhang ◽  
H. J. Curran
Keyword(s):  
Chemical Kinetics ◽  
Laminar Flame ◽  
Combustion Process ◽  
Time History ◽  
Good Marker ◽  
Ignition Delay Times ◽  
Depletion Rate ◽  
Time Histories ◽  
Main Components ◽  
Detailed Kinetics

Methane and ethane are the two main components of natural gas and typically constitute more than 95% of it. In this study, a mixture of 90% CH4/10% C2H6 diluted in 99% Ar was studied at fuel lean (equiv. ratio = 0.5) conditions, for pressures around 1, 4, and 10 atm. Using laser absorption diagnostics, the time histories of CO and H2O were recorded between 1400 and 1800 K. Water is a final product from combustion, and its formation is a good marker of the completion of the combustion process. Carbon monoxide is an intermediate combustion species, a good marker of incomplete/inefficient combustion, as well as a regulated pollutant for the gas turbine industry. Measurements such as these species time histories are important for validating and assessing chemical kinetics models beyond just ignition delay times and laminar flame speeds. Time-history profiles for these two molecules were compared to a state-of-the-art detailed kinetics mechanism as well as to the well-established GRI 3.0 mechanism. Results show that the H2O profile is accurately reproduced by both models. However, discrepancies are observed for the CO profiles. Under the conditions of this study, the CO profiles typically increase rapidly after an induction time, reach a maximum, and then decrease. This maximum CO mole fraction is often largely over-predicted by the models, whereas the depletion rate of CO past this peak is often over-estimated for pressures above 1 atm.

CH Kinetics Measurements and Their Importance for Modeling Prompt NOx Formation in Gas Turbines

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
Sean P. Cooper ◽  
Clayton R. Mulvihill ◽  
Olivier Mathieu ◽  
Eric L. Petersen ◽  
Mark W. Crofton ◽  
...  
Keyword(s):  
Shock Tube ◽  
Chemical Kinetics ◽  
Gas Turbines ◽  
Near Infrared ◽  
Elevated Temperatures ◽  
Frequency Doubling ◽  
Tunable Laser ◽  
Detailed Chemical Kinetics ◽  
Reflected Shock ◽  
Time Histories

Abstract Recent work by the authors and others has uncovered the need for further chemical kinetic-related modeling and experiments, specifically for NOx kinetics at engine conditions. In particular, data on CH formation at realistic combustion conditions are needed for further refinement of the prompt-NOx kinetics. To this end, a series of shock-tube experiments to obtain CH concentration time histories at elevated temperatures was performed behind reflected shock waves at the Aerospace Corporation using a tunable laser. This Ti-Sapphire laser was operated in the near infrared at about 854 nm; blue light at 426.9 nm was obtained using an external, frequency-doubling crystal. The resulting light was used in a differential absorption setup with common-mode rejection to measure CH time histories. New measurements in CH4–C2H6–O2 mixtures highly diluted in argon were performed at temperatures between 1890 K and 2719 K. These new data are compared to several modern, detailed chemical kinetics mechanisms with updated NOx submechanisms. Sensitivity and rate of production analyses at the shock-tube conditions along with a gas turbine model are used to elucidate the current state of affairs in CH prediction by the literature models and its effect on NOx production, particularly through the prompt mechanism. A brief discussion of the chemical kinetics for an important reaction in the production of CH is also presented to emphasize the need for further study and refinement of reactions leading to CH production.

scholarly journals Guidlines for Inventors “From Idea to Product”

2020 ◽  
Author(s):  
Roberts Kaķis ◽  
Dagnija Blumberga ◽  
Ģirts Vīgants
Keyword(s):  
Life Cycle ◽  
Natural Gas ◽  
Life Cycle Analysis ◽  
Ecological Footprint ◽  
Patent Application ◽  
Wood Dust ◽  
Gas Burner ◽  
Reduce Emissions ◽  
Main Components ◽  
Fine Wood

The article deals with the problem facing Latvian inventors in how to develop the idea to a real product. There are often cases where innovative ideas “migrate” from original inventors to other inventors, when they turn to them to seek support for developing and supporting the idea. The main components of the guidelines are the establishment of a patent application and, in general, a description of the entire patent acquisition process and the creation of a life cycle analysis using the SimaPro software. The article is intended primarily for the development of environmentally friendly inventions, which is why the life cycle analysis is one of the main components of the article, to make it possible to conclude whether the production and use of the new product will not result in a higher “ecological footprint” than previously used technologies, paying particular attention to the inventor stage in order to accurately develop a life-cycle analysis. The article does not only explore the necessary theoretical knowledge of the realisation of the idea to the product, but also looks at the pilot case, a practical example of an innovative “dust co-firing burner” compared to the conventional natural gas burner. The life-cycle analysis compares the following steps: manufacture of plants, transportation of plants and special emphasis on the combustion phase of fuels, three scenarios are examined: a natural gas burner burning natural gas, a dust burner in which natural gas is co-incinerated and fine wood particles − dust and a dust burner burning. biomethane and wood dust. The use of such an installation would not only reduce emissions from the replacement of natural gas by wood dust, but also allow energy companies to work more effectively, as it would be possible to regulate the proportion of different fuels depending on demand, because the fuels have different heat of combustion. The article establishes a methodology to analyse the quality and implementation of inventions in response to the following key questions: − how to identify original ideas and how to protect authors from the migration of ideas; − how to collect and analyse the risks associated with migration of ideas; − how to use life cycle analysis for the assessment of the “ecological footprint” of the invention.

A shock tube and laser absorption study of CO time-histories during bio ether oxidation

2019 ◽  
Author(s):  
Andrew Laich ◽  
Erik M. Ninnemann ◽  
Owen Pryor ◽  
Sneha Neupane ◽  
Subith Vasu
Keyword(s):  
Shock Tube ◽  
Absorption Study ◽  
Laser Absorption ◽  
Time Histories

Shock tube and laser absorption study of CO time-histories during combustion of branched alkenes

2020 ◽  
Author(s):  
Farhan Arafin ◽  
Andrew Laich ◽  
Ramees Rahman ◽  
Erik M. Ninnemann ◽  
Robert Greene ◽  
...  
Keyword(s):  
Shock Tube ◽  
Absorption Study ◽  
Laser Absorption ◽  
Time Histories

scholarly journals Influence of the double bond position in combustion chemistry of methyl butene isomers: A shock tube and laser absorption study

2020 ◽  
Vol 52 (11) ◽  
pp. 739-751 ◽  
Author(s):  
Farhan Arafin ◽  
Andrew Laich ◽  
Erik Ninnemann ◽  
Robert Greene ◽  
Ramees K. Rahman ◽  
...  
Keyword(s):  
Double Bond ◽  
Shock Tube ◽  
Double Bond Position ◽  
Absorption Study ◽  
Combustion Chemistry ◽  
Laser Absorption

CFD Modelling of Biogas Cofiring in a Gas Turbine

2002 ◽  
Author(s):  
J. A. Lycklama a` Nijeholt ◽  
E. M. J. Komen ◽  
R. T. E. Hermanns ◽  
L. P. H. de Goey ◽  
M. C. van Beek ◽  
...  
Keyword(s):  
Natural Gas ◽  
Gas Turbines ◽  
Burning Velocity ◽  
Combustion Process ◽  
Combustion Model ◽  
Cfd Modelling ◽  
Combustion Chemistry ◽  
Feasible Option ◽  
Safe Limit ◽  
The Stability

Cofiring of biogas in existing gas turbines is a feasible option to reduce the consumption of natural gas. However, admixing of biogas will have an effect on the combustion process. As a consequence, the burning velocity and, therefore, the flame stability may be affected when a significant amount of biogas is mixed with the natural gas. The effect of admixing natural gas with biogas on the stability of the combustion process in lean premixed gas turbines is insufficiently known. In the present paper, a Computational Fluid Dynamics (CFD) methodology will be presented for the assessment of the safe limit of biogas cofiring in a gasturbine. An advanced Flamelet/Flamefront combustion model [1, 2, 3] and the Coherent Flame Model [4] are utilized. In both models, the detailed GRI 3.0 reaction mechanism [5] has been used to describe the combustion chemistry. The degree of mixing of fuel and air in the lean premix-burners of the gasturbine has been determined with a separate CFD model of the burners.

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