Data-driven prediction of flame temperature and pollutant emission in distributed combustion

Combustion with diluted syngas is important for integrated gasification combined cycle (IGCC) system that attains high efficiency and low pollutant emissions. In syngas diffusion flames, peak flame temperature is higher than that in nature gas flames, so NOx emission is more significant. To achieve low NOx emission, fuel dilution is an effective way. In the present study, Flame structure and emission characteristics were experimentally and numerically studied in various fuel diluted syngas diffusion flames, and H2O, N2 and CO2 were employed as diluents respectively. The purpose of this paper is to better understand the behavior and mechanism of fuel diluted combustion and to provide fundamental data base for the development of syngas combustion techniques. Experiments were conducted by using jet diffusion flames in a model combustor. Flame size, exhaust temperature and emission concentration were measured. It was found that by introducing diluents into fuel stream, the stoichiometric surface was brought inward, namely the flame envelope shrunk due to a relatively low fuel concentration. The exhaust temperature was decreased. The results also indicated that with diluted fuel stream, there was an increase of CO emission and an apparent decrease of NO emission. For the same exhaust temperature, H2O had the most significant influence on NO emission among the three diluents, while CO2 affected CO emission most by inhibiting its oxidation thermally and chemically. Numerical simulations were performed in counterflow diffusion flames by applying Chemkin software. To reveal the mechanisms of various diluents in flames, the detailed chemistry of H2-CO-N2 system was employed. It was found that the concentration of OH radical is important for both NO and CO emissions. The OH concentration is affected not only by the type of diluents but also by the flame temperature, therefore it is determined by the coupling and competition of diluents’ chemical and thermal effects.

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On the Prediction of Pollutant Emission [NOx] in Internal Combustion Engine

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.824.505 ◽

2013 ◽

Vol 824 ◽

pp. 505-513

Author(s):

B.Y. Ogunmola ◽

S.M. Abolarin ◽

A.O. Adelaja

Keyword(s):

Internal Combustion Engine ◽

Combustion Engine ◽

Flame Temperature ◽

Combustion Process ◽

Internal Combustion ◽

Spark Ignition Engine ◽

Pollutant Emission ◽

Matlab Simulation ◽

Combustion Time ◽

Equilibrium Equations

The study of internal chemical processes involving nitrogenous species forms an important part in the understanding of parameters which lower NOxemission from combustion systems. The focus of this research is to numerically model the prediction of formation of pollutant emission in a continuous internal combustion engine (ICE), from finite rate chemical equilibrium equations. The main source of nitrogen in the chemical formation of NOxis atmospheric, and a very small portion is caused by nitrogen compounds found in some fuels. A mathematical modeling was carried out with these equations using MATLAB simulation to predict the concentration of Nitric Oxide NO; a pollutant, at different flame temperatures and reaction timing of ICE. The temperatures under consideration vary from 1500K to 2300K. The concentration of the pollutant was evaluated by the analytical and numerical methods for a spark ignition engine at a temperature of 2000K; pressure of 1atm, considering a sample containing 78% of Nitrogen and 4% of Oxygen and 78% Nitrogen and 21% Oxygen held between zero to one second in the course of the combustion process, while the computer programme simulated between zero and 100seconds. The concentrations predicted were found to increase as the flame temperature, the combustion time increase as depicted on the results and as the percentage composition of Oxygen in the mixture increases, but reduces with increasing fuel nitrogen content.

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Can hydrogen enriched biogas be used as domestic fuel? - Part I – Thermal Characteristics of Blended Biogas/H2 Impinging Flames

HKIE Transactions ◽

10.33430/v28n2thie-2020-0040 ◽

2021 ◽

Vol 28 (2) ◽

pp. 60-67

Author(s):

Yi Chen ◽

Udaya Kahangamage ◽

Quan Zhou ◽

Chun Wah Leung

Keyword(s):

Heat Flux ◽

Reynolds Number ◽

Equivalence Ratio ◽

Fossil Fuels ◽

Flame Temperature ◽

Thermal Characteristics ◽

Pollutant Emission ◽

Heating Value ◽

Flux Profile ◽

H2 Addition

Biogas is a renewable energy source widely produced by breakdowns of organic matters in natural environment and industry. However, it is not yet an ideal replacement of fossil fuels because its high CO2 content would deteriorate its thermal performance. To upgrade biogas for possible domestic application, hydrogen enrichment is proposed by adding high-grade hydrogen (H2) to biogas in order to improve its flammability and heating value, and reduce pollutant emission. However, most previous studies on blended Biogas/H2 focus on analysing the effects of H2 fraction and nozzle-to-plate distance on the heat flux profile and flame temperature. No comprehensive study has ever demonstrated the influence of the Reynolds number and equivalence ratio under a wide operating range. In this study, a test rig was built to investigate the effects of the Reynolds number and equivalence ratio on heat flux and thermal efficiency of blended biogas/H2 impinging flame. The blended biogas/H2 consisted of 80% biogas and 20% H2 addition in volume. Biogas was artificially made by 60% CH4 and 40% CO2 (BG60). The Reynolds number ranges from 300 to 1500 and equivalence ratio ranges from 1 to 3. A comparative study was also conducted between pure biogas (BG60) and biogas with 20% H2 enrichment.

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Electron microscopy studies of plasma-sprayed materials

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100074276 ◽

1983 ◽

Vol 41 ◽

pp. 70-71

Author(s):

K.R. Subramanian ◽

A.H. King ◽

H. Herman

Keyword(s):

Plasma Spraying ◽

Substrate Surface ◽

Flame Temperature ◽

Ceramic Coatings ◽

Metallic Substrates ◽

Hot Plasma ◽

Almost All ◽

Plasma Sprayed ◽

Hostile Environments ◽

Plasma Spraying Process

Plasma spraying is a technique which is used to apply coatings to metallic substrates for a variety of purposes, including hardfacing, corrosion resistance and thermal barrier applications. Almost all of the applications of this somewhat esoteric fabrication technique involve materials in hostile environments and the integrity of the coatings is of paramount importance: the effects of process variables on such properties as adhesive strength, cohesive strength and hardness of the substrate/coating system, however, are poorly understood.Briefly, the plasma spraying process involves forming a hot plasma jet with a maximum flame temperature of approximately 20,000K and a gas velocity of about 40m/s. Into this jet the coating material is injected, in powder form, so it is heated and projected at the substrate surface. Relatively thick metallic or ceramic coatings may be speedily built up using this technique.

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