Investigation of the Soot Formation in Ethylene Laminar Diffusion Flames When Diluted with Helium or Supplemented by Hydrogen

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Energy and Fuels, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://dx.doi.org/10.1021/ef401970qA new optical diagnostic technique has been used to measure the spatially distributed temperatures, soot diameters, and soot volume fractions in several different ethylene laminar diffusion flames to investigate the effect of adding hydrogen and helium on the soot formation. The test results show that adding hydrogen increases the flame temperature in all regions, while adding helium does not significantly affect the flame temperature in the reaction region but does increase the flame temperature elsewhere. The flame heights when adding helium and hydrogen can be calculated using the correlation introduced by Roper if the ethylene diffusion coefficient is used. This indicates that the flame height is determined by the diffusion of ethylene molecules when the hydrogen fraction is below 20%. It was also found that either adding helium or hydrogen does not significantly affect the soot diameter but does reduce the soot volume fraction. A total of 20% of helium addition by volume was measured to reduce the total soot number by 19%, while a total of 20% of hydrogen addition reduced the total soot number by 23%. In comparison, replacing the hydrocarbon with hydrogen is much more effective in reducing soot formation. Replacement of 25% ethylene by hydrogen was measured to reduce the total soot number by 66%. Apart from demonstrating the influence of hydrogen and helium on ethylene diffusion flames, these measurements provide additional data for modelers of diffusion flames, especially those with an interest in the formation of particulate matter. © 2014 American Chemical Society

Analysis of the effect of H 2 0 content on combustion behaviours of a biogas fuel

The present work deals with the biogas in a combustor with regard to its combustion features under differing conditions of H 2 0 content and H 2 S. The content of water (H 2 O) vapour has been changed from 0% to 10% and a CFD code has been employed while implementing numerical investigations. In modelling, a combustion model (the PDF/Mixture Fraction) along with a turbulence model (the k-? standard turbulence model) has been utilised. This study also deals with the combustion performances of the biogas by the addition of a different quantity of H 2 O into the biogas. The Emissions and the flame temperature of the biogas through the combustor apparently seem to be strikingly affected by the changes in H 2 O contents. It is interesting to note that the flame temperature zones change their positions and advance to the burner's downstream. The rise in flame temperatures of the biogas can be attributed to the change in H 2 O content caused by a better fuel-air mixture. It is also observed that adding H 2 O into the biogas lowers the axial temperature levels. © 2019 Hydrogen Energy Publications LL

Investigation of thermal aspects of hydrogen storage in a LaNi5-H2 reactor

In this work, hydrogen absorption in a LaNi5-H2 reactor is investigated experimentally and numerically. Experimental measurements were carried out on a cylindrical metal-hydride reactor filled with LaNi5 alloy. During the experiments hydrogen was charged at a constant pressure. The performance of the reactor during hydriding process was obtained at different fluid temperatures and hydriding process was identified from measured temperature histories. The temperature changes in the reactor were measured at several locations and recorded in a computer. The numerical simulation of the reactor was also performed. A two-dimensional mathematical model has been established and solved numerically by the method of finite volume for the simulation. The numerical results are compared with the measured data to validate the mathematical model. The predicted results are in good agreement with the experimental measurements. Copyright © 2005 John Wiley & Sons, Ltd

Reduction of Energy Cost and CO2 Emission for the Boilers in a Full-Scale Refinery Plant by Adding Waste Hydrogen-Rich Fuel Gas

[[abstract]]The use of hydrogen-containing fuel in gas turbines and industrial burners can benefit both losses of radiative heat and emission of pollutants. In this study, worthless waste hydrogen-rich fuel gas (RG) was led into a high-pressure boiler or a medium-pressure boiler in the fuel system to partially replace fuel oil (FO) and/or natural gas (NG) in a full-scale petrochemistry plant. Two sets of inlet fuel flow rate ratios were examined to evaluate the reductions of boiler energy consumption and CO2 emission. The result showed that for the high-pressure boiler at a loading of 75%, the usage of NG can be 13 × 106 m3/y less and the CO2 emission can be 2.2 × 104 tons/y lower by changing the inlet FO:NG:RG ratio from 1:1:0 to 1:0.65:0.35. Meanwhile, for the medium-pressure boiler at a loading of 70%, the usage of NG can be cut by 8 × 106 m3/y and the CO2 emission can be 3.0 × 104 tons/y lower by changing the inlet FO:RG ratio from 1:0.2 to 1:0.7. Therefore, the addition of RG has practical benefits on both energy saving and the reduction of greenhouse gas emission