Re: methane slip - measured non combusted methane in a gas engine is 1.7%??
dave andrews
Subject: Re: methane slip - measured non combusted methane in a gas engine is 1.7%??
Following this debate is interesting, but I think it needs some focus.
Is CH4 a worse greenhouse gas than CO2?…. Yes. Should this be taken into account?….. yes.
Is this being taken into account?.... presumably yes, since the emissions legislation includes this parameter.
Is this being taken into account further up the chain by climatologists?.... I have no idea, but that isn’t something the engine manufacturers can do much about, and what climate scientists include in their calcs is not something subject to legislation.
There seems to be some idea that the quoted 1.7% is bad, and in absolute climate terms this could be argued to be the case, but we have to assume that if people don’t use a piston engine they will produce the same power by some other means, and that might be as bad, worse or better. So the real issues are:
What are the total greenhouse gas emissions of engines compared to other equivalent means of power production with similar emissions of other pollutants?
How could this be improved?
Do we actually need this power at all?
What is the world doing to reduce total energy demand and thereby emissions?
Personally I’d ban a few other things first: illuminated advertising (what a pointless waste of power), patio heaters (the improvement in carbon emissions of the entire UK company car fleet was wiped out by the sale of patio heaters).
You have to remember that according to the laws of thermodynamics we can’t make things better. We can only alter the rate at which they get worse!
From: dave andrews [mailto:tynin...@gmail.com]
Sent: 30 November 2011 11:43
To: Claverton Diesel+GT group; Claverton AB MAIN GROUP
Subject: Re: methane slip - measured non combusted methane in a gas engine is 1.7%??
Thanks David, and are the latest machines miller cycle?
Dave
On 30 November 2011 12:21, David Hatherill (UK) <dhath...@finning.co.uk> wrote:
Dave,
With regard to Fred’s comment about whether combustion is good or not I think this has to be benchmarked against other types of combustion. All types of combustion are imperfect in one way or another, and all have unburnt end gases.
I also think we need to remember that combustion is “optimised” and many of the factors compete with each other. This does result in a trade off, and to a large extent this trade off is considered on a regulatory basis. It is not something the engine manufacturers determine, although of course as technology improves there are certain things that we couldn’t do before. Much of modern engine technology is about control and this means we can more accurately control and map the engine to make sure it meets performance parameters with greater accuracy, but the trade off itself still remains. A good example of the trade off is efficiency vs emissions, and then of course within emissions there are further trade offs.
With regard to emissions, increasingly manufacturers are using after treatment, and of course this isn’t about changing the combustion process at all, but about making changes to the engine package as a whole to make them more compliant.
So in summary, I think the figure needs framing in some context.
David
David Hatherill
Engineering Manager
Finning Power Systems
688-689 Stirling Road, Slough SL1 4ST, UK
From: dave andrews [mailto:tynin...@gmail.com]
Sent: 30 November 2011 10:36
To: engines-gas-die...@googlegroups.com
Cc: Claverton AB MAIN GROUP; Ron Bickerton
Subject: Re: methane slip - measured non combusted methane in a gas engine is 1.7%??
I think the latest ones are all Miller cycle....a lot of the slip as I understand it is from the turbo crossover...I think blow by gases are all fed back into the air inlet, but after the air filter to avoid clogging with oil mist.....
On 30 November 2011 11:33, star...@yahoo.com <star...@yahoo.com> wrote:
Dear Dave Andrews
I think I have also seen this figure, which is partly connected with the hide out of gases down the sides of the piston....But I agree with Dave Hatheril that the real cause is running engines rich, so that catalytic convertors will work properly and NOx emissions are minimised.
However I don't think combustion in IC engines is very good, as is shown by the CO content of the exhaust gas. This represents incomplete combustion.
One point worth thinking about is whether the application of the Atkinson and Miller cycles may allow more time for complete combustion.
Best regards
Fred
From: dave andrews <tynin...@gmail.com>
To: Claverton AB MAIN GROUP <energy-disc...@googlegroups.com>; Claverton Diesel+GT group <engines-gas-die...@googlegroups.com>; Ron Bickerton <bicke...@deutz.com>
Sent: Tuesday, 29 November 2011, 17:15
Subject: Re: methane slip - measured non combusted methane in a gas engine is 1.7%??Dave,
It’s a bit difficult to calculate due to the way the figures are quoted, but having done some quick calcs (not for professional scrutiny, as I didn’t properly correct the exhaust flow from dry to wet or the O2) this doesn’t seem to be too far off.
You have to realise that some engine data sheets quote the not to exceed figure which is much higher than nominal measured levels.
There are also many other factors which effect these and of course good low NOx performance is somewhat counter productive to this aim.
I’d be interested to benchmark this figure against other conversion technologies because if you say 98.3% of all fuel input is combusted it sounds quite an efficient process.
I’d be more concerned that the amount of methane that leaks straight into the atmosphere, some of which has never been measured. How much leaks out of badly capped landfills?......... nobody knows…..in many places abroad they just vent them to atmosphere with no flare.
Cheers
David
David Hatherill
Engineering Manager
Finning Power Systems
688-689 Stirling Road, Slough SL1 4ST, UK
Subject: methane slip - 1.7%?
Hey Dave,
At a presentation today, it was stated that the measured non combusted methane in a gas engine is 1.7%??
This seems extraordinarily high?
As a major gas engine supplier, can you comment on your experience?
Thanks
On 29 November 2011 17:29, dave andrews <tynin...@gmail.com> wrote:
Gentlemen / Ladies,
At a presentation today, it was stated that the measured non combusted methane in the exhaust of a gas engine is 1.7%??
This seems extraordinarily high?
Can anyone comment authoritatively?
Thanks
--Dave Andrews
K.E.N.T.
+ 44 (0) 755 265 9166
--Dave Andrews
K.E.N.T.
+ 44 (0) 755 265 9166
--Dave Andrews
K.E.N.T.
+ 44 (0) 755 265 9166
--Dave Andrews
K.E.N.T.
+ 44 (0) 755 265 9166
This email and any files transmitted with it are confidential and intended solely for the individual to whom they are addressed. If you have received this email in error please delete the message immediately, and notify the sender. Any rights not expressly granted herein are reserved. Reproduction, transfer or distribution of part or all of the contents in any form without the prior written permission of Finning (UK) Ltd. Is prohibited. Views or opinions presented are solely those of the author and do not necessarily represent those of Finning (UK) Ltd. Please note that we reserve the right to monitor and read any emails sent and received by the Company under the Telecommunications (Lawful Business Practice) (Interception of Communications) Regulations 2000 Although Finning (UK) Ltd. has taken every reasonable precaution to ensure that any e-mails have been checked for viruses, it is the responsibility of the recipient to ensure this e-mail and its attachments are virus free before opening. Finning (UK) Ltd. accepts no liability for any damage caused by any virus transmitted by this email. Finning (UK) Ltd is a company registered in England and Wales (Company Registration Number 367090) and it's registered office is at Watling Street, Cannock, Staffordshire WS11 8LL Copyright Finning (UK) Ltd. 2004
--Dave Andrews
K.E.N.T.
+ 44 (0) 755 265 9166
This email and any files transmitted with it are confidential and intended solely for the individual to whom they are addressed. If you have received this email in error please delete the message immediately, and notify the sender. Any rights not expressly granted herein are reserved. Reproduction, transfer or distribution of part or all of the contents in any form without the prior written permission of Finning (UK) Ltd. Is prohibited. Views or opinions presented are solely those of the author and do not necessarily represent those of Finning (UK) Ltd. Please note that we reserve the right to monitor and read any emails sent and received by the Company under the Telecommunications (Lawful Business Practice) (Interception of Communications) Regulations 2000 Although Finning (UK) Ltd. has taken every reasonable precaution to ensure that any e-mails have been checked for viruses, it is the responsibility of the recipient to ensure this e-mail and its attachments are virus free before opening. Finning (UK) Ltd. accepts no liability for any damage caused by any virus transmitted by this email. Finning (UK) Ltd is a company registered in England and Wales (Company Registration Number 367090) and it's registered office is at Watling Street, Cannock, Staffordshire WS11 8LL Copyright Finning (UK) Ltd. 2004
--
+ 44 (0) 755 265 9166
+ 44 (0) 1225 837978