Issues for low-emission, fuel-flexible power systems

Richards, George; McMillian, M.M; Gemmen, Randall; Rogers, William A.; Cully, S.R

doi:10.1016/s0360-1285(00)00019-8

Cited by 217 publications

(98 citation statements)

References 64 publications

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“…Natural gas could be used in internal combustion engines and gas turbines [1,2], but its application has been limited because of unstable ignition and combustion. Experimental [3] and computational [4] studies have shown that addition of hydrogen to natural gas improves the tolerance of exhaust gas recirculation (EGR) and greatly reduces NO x and hydrocarbon emissions, while maintaining the engine power.…”

mentioning

confidence: 99%

Experimental and kinetic study on ignition delay times of methane/hydrogen/oxygen/nitrogen mixtures by shock tube

et al. 2011

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Ignition delay times of methane/hydrogen/oxygen/nitrogen mixtures with hydrogen amount-of-substance fractions ranging from 0-20% were measured in a shock tube facility. The ambient temperature varied from 1422 to 1877 K and the pressure was maintained at 0.4 MPa behind the reflected shock wave. The experiments were conducted at an equivalence ratio of 2.0. The fuel mixtures were diluted with nitrogen gas so that the nitrogen amount-of-substance fraction was 95%. The experimental ignition delay time of the CH 4 /H 2 mixture decreased as the hydrogen amount-of-substance fraction increased. The enhancement of ignition by hydrogen addition was weak when the ambient temperature was >1750 K, and strong when the temperature was <1725 K. The ignition delay time of 20% H 2 /80% CH 4 was only one-third that of 100% CH 4 at 1500 K. A modified model based on GRI-Mech 3.0 was proposed and used to calculate the ignition delay times of test mixtures. The calculated results agreed with the experimental ignition delay times. Normalized sensitivity analysis showed that HO·+H 2 →H·+H 2 O was the main reaction for the formation of the H· at 1400 K. As the hydrogen amount-of-substance fraction increased, chain branching was enhanced through the reaction H·+O 2 →O·+HO·, and this reduced the ignition delay time. At 1800 K, the methyl radical (H 3 C·) became the key species that influenced the ignition of the CH 4 /H 2 /O 2 /N 2 mixtures, and sensitivity coefficients of the chain termination reaction 2H 3 C·(+M)→C 2 H 6 (+M), and chain propagation reaction HO 2 +H 3 C·→HO·+CH 3 O decreased, which reduced the influence of hydrogen addition on the ignition of the CH 4 /H 2 mixtures.shock tube, methane, hydrogen, chemical kinetics Citation:Zhang Y J, Huang Z H, Wei L J, et al. Experimental and kinetic study on ignition delay times of methane/hydrogen/oxygen/nitrogen mixtures by shock tube.

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confidence: 99%

Experimental and kinetic study on ignition delay times of methane/hydrogen/oxygen/nitrogen mixtures by shock tube

et al. 2011

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“…The biomass resource base was assumed to be 50 tonnes/day of dung, woody and leafy material and was modelled as costless in the base case and tested for sensitivity at 5 $/tonne. The biogas produced by the digester at a ratio of 0.7 kg of gas/kg of biomass is assumed to have a 7 MJ/m 3 high heating value and consists of nitrogen, hydrogen and carbon monoxide gases (Richards et al, 2001). …”

Section: Biomass Resourcesmentioning

confidence: 99%

An Economic Evaluation of Small-scale Distributed Electricity Generation Technologies

Hansen¹,

Bower²

2003

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All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, o r transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior permission of the Oxford Institute for Energy Studies.This publication is sold subject to the condition that it shall not, by way of trade or otherwise, be lent, resold, hired out, or otherwise circulated without the publisher's consent in any form or binding or cover other than that in which it is published and without similar condition including this condition being imposed on the subsequent purchaser.

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“…The levels of these species vary substantially with geographical source, time of year, and treatments applied during production or transportation. The addition of unconventional and bio-derived gases to fossil natural gas can have an even greater effect on fuel composition (Richards, McMillian, Gemmen, Rogers, & Cully, 2001). Natural-gas fueling can reduce greenhouse gas (GHG) emissions compared to diesel; adding hydrogen to the natural gas offers even further GHG reductions from transportation applications (McTaggartCowan et al, 2007a).…”

Section: Introductionmentioning

confidence: 99%

Investigation of the Effect of Additives to Natural Gas on Heavy-Duty SI Engine Combustion Characteristics

Gharehghani¹,

Hosseini²,

Yusaf³

2013

J MECH ENG SCI

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This work investigates the implications of natural-gas composition on the combustion in a heavy-duty natural-gas engine and on the associated pollutant emissions. Natural gas is injected in ports and mixes with air before entering the cylinder. For the ignition source, both a spark plug and diesel pilot, which is injected before the top-dead center in the cylinder, are used. The effect of additives such as hydrogen, ethane and nitrogen on the output power and efficiency of the engine and emission levels are examined. The results indicate that these additives had no significant effect on the engine's power or fuel consumption. Emissions of unburned fuel are reduced for all additives through either enhanced ignition or combustion processes. Adding ethane and H 2 to the fuel increases the in-cylinder pressure and NOx emission, while fuel dilution with N 2 has a critical amount. Black carbon particulate matter emissions are increased by ethane, but are virtually eliminated by including nitrogen or hydrogen in the fuel. The results show the higher flame speed of ethane compared to hydrogen, and hydrogen compared to methane. Thus, to reach the MBT condition, the spark time of ethane is the most retarded one and for methane it is the most advanced.

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Issues for low-emission, fuel-flexible power systems

Cited by 217 publications

References 64 publications

Experimental and kinetic study on ignition delay times of methane/hydrogen/oxygen/nitrogen mixtures by shock tube

Experimental and kinetic study on ignition delay times of methane/hydrogen/oxygen/nitrogen mixtures by shock tube

An Economic Evaluation of Small-scale Distributed Electricity Generation Technologies

Investigation of the Effect of Additives to Natural Gas on Heavy-Duty SI Engine Combustion Characteristics

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