Natural Gas Powered Locomotives

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Posted by Wizlish on Monday, February 01, 2016 10:01 AM

One consideration for steam injection would involve heat transfer to a HRSG in a combined-cycle plant -- which I would expect any 'modern' locomotive gas turbine of appreciable size or peak output to consider. 

I am not sure how many people actually observed the interesting result from using steam injection (nominally I believe for NOx reduction) in the Donlee TurboXL boiler that the Feds tested.  The steam itself serves as a heat-transfer agent, if there is adequate surface at the 'right' temperature range downstream.  If I recall correctly this is not just limited to feedwater-heating; you can actually get meaningful heat uptake from the steam above the phase-change temperature, so much of the energy in the injected steam is not 'wasted' (as was apparently the assumption when the NOx-reduction system was designed).

In a CC design with relatively limited paths, anything that increases or accentuates heat uptake in the HRSG may be a meaningful benefit.  Remains to be seen if appreciable additional horsepower can be derived from a bottoming cycle at even large locomotive scale, cost-effectively, particularly if the heat drop in combustion gas through a NG turbine, or the observed turbine peak temperature, can be made 'better' than for regular gas-turbine fueling.

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Posted by carnej1 on Monday, February 01, 2016 11:33 AM

Wizlish

One consideration for steam injection would involve heat transfer to a HRSG in a combined-cycle plant -- which I would expect any 'modern' locomotive gas turbine of appreciable size or peak output to consider. 

I am not sure how many people actually observed the interesting result from using steam injection (nominally I believe for NOx reduction) in the Donlee TurboXL boiler that the Feds tested.  The steam itself serves as a heat-transfer agent, if there is adequate surface at the 'right' temperature range downstream.  If I recall correctly this is not just limited to feedwater-heating; you can actually get meaningful heat uptake from the steam above the phase-change temperature, so much of the energy in the injected steam is not 'wasted' (as was apparently the assumption when the NOx-reduction system was designed).

In a CC design with relatively limited paths, anything that increases or accentuates heat uptake in the HRSG may be a meaningful benefit.  Remains to be seen if appreciable additional horsepower can be derived from a bottoming cycle at even large locomotive scale, cost-effectively, particularly if the heat drop in combustion gas through a NG turbine, or the observed turbine peak temperature, can be made 'better' than for regular gas-turbine fueling.

 

Actually I would very much doubt the North American freight railroads would seriously look at combined cycle locomotives. That is an industry that lives by the Acronym "K.I.S.S" and some immensely complex beast like this:

https://patents.google.com/patent/US20100005775A1/en?q=combined+cycle&q=locomotive

-is going to have to compete with kits to adapt existing diesel electric locomotives (with common engine designs that the RRs already have large parts inventories for) to dual fuel operation as already being tested currently in conjunction with both GE and Cat/Progress/EMD.

"I Often Dream of Trains"-From the Album of the Same Name by Robyn Hitchcock

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Posted by Wizlish on Monday, February 01, 2016 4:58 PM

I should be a bit more specific when I say 'combined cycle' -- I don't mean the kind used on gas-turbine peaking powerplants, where there's plenty of room and plenty of weight-bearing structure for a whole Rankine-cycle bottom end to a Brayton-cycle engine.  I was thinking more of the two interesting BMW projects, the "steam" one that produced something like 5-15% of the main engine output, and the fuel-cell one that was sized to power all the ancillaries independent of main-engine power setting (leaving  the combustion engine's power entirely for traction).  There is a tremendous amount of heat remaining in even a good regenerative gas turbine's exhaust, and (as with reciprocating steam  power!) there is quite a bit of 'free' heat available in the exhaust, if you can extract it without operating compromise and the costs don't outweigh the advantages.

The checkered history of Franco-Crosti arrangements built out of cheap carbon steels and applied to relatively elderly and primitive locomotives are a detailed cautionary tale about what works and what doesn't in a thermal bottoming cycle.  The situation is of course easier with a natural-gas turbine exhaust (and with the capacity for makeup gas burning in any HRSG arrangement), but it is, as carnej1 indicates, comparatively unlikely that useful 'marginal' traction horsepower will be generated by the bottoming part of a combined-cycle locomotive arrangement.  Which leaves the discussion asking 'what can the bottoming part cost-effectively provide that the turbine is relatively ill-suited to do?'

Beyond this, neither size nor complexity is to a designer's advantage, and in the absence of provable benefits it is wiser, as carnej1 indicates, 'not to play'.

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Posted by f45gnbn on Monday, February 01, 2016 9:57 PM
Think of top fuel dragsters and other race cars burning alcohol. when you switch from burning gas to alcohol you increase the fuel rate so you use similar btu's of fuel. you have to get enough fuel in the air for it to burn well. If you drop 40 % less fuel it may not even ignite because there is too much air there. you've got to get the right fuel air mixture so its not 1gal of diesel fuel used to injecting 1gal of LNG. Think of airplanes, they don't measure fuel in gal, they measure in LBS because it is a more accurate representation of the amount of fuel used.
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Posted by carnej1 on Tuesday, February 02, 2016 11:11 AM

f45gnbn
Think of top fuel dragsters and other race cars burning alcohol. when you switch from burning gas to alcohol you increase the fuel rate so you use similar btu's of fuel. you have to get enough fuel in the air for it to burn well. If you drop 40 % less fuel it may not even ignite because there is too much air there. you've got to get the right fuel air mixture so its not 1gal of diesel fuel used to injecting 1gal of LNG. Think of airplanes, they don't measure fuel in gal, they measure in LBS because it is a more accurate representation of the amount of fuel used.
 

 I read that the Cat/EMD dual fuel diesel system uses a 60/40 LNG/diesel ratio while the GE system runs on 80% LNG and 20% Diesel:

 

http://www.railwayage.com/index.php/mechanical/locomotives/locomotives-is-lng-the-next-generation.html

 Back in the late 1990's/Early 2000's Railpower Industries was trying to interest the railroad industry in a Compressed Natural Gas fueled Gas Turbine-Electric road locomotive but the design never made it into iron:

http://turbotrain.net/en/cingl.htm

 

"I Often Dream of Trains"-From the Album of the Same Name by Robyn Hitchcock

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Posted by JOSEPH RENNER on Wednesday, February 03, 2016 3:14 PM

Euclid
I interpret Mr. Midget to be saying that the third unit is needed to make up for the lower BTU content of natural gas compared to diesel; as opposed to a need for extra power to haul the fuel tender. 
 

 

the lower btu rating won't decrease locomotive performance rather the the locomotive will end up burning up more fuel to get that same amount of energy. Adding another engine would only increase fuel cosumption.

 

TRAINS has article about FECs commitment to LNG. In current issue

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Posted by loco6625 on Thursday, February 04, 2016 4:27 PM

you are correct that Cat did offer a pure natural gas engine in the late 70s I belive. In fact I remember a Cat dealer in the Chicago, Il. area had 3 possibly the V-8 1700 series diesel converted gen sets to natural gas with magnito/spark plug ignition, and an automotive type carburator. They were the source of electric power for the whole plant. And were used as demonstrators by Cat engineering and sales departments. One of the selling features was the lack of sulffer contamation in the lube oil verses diesel fuel. It really didn't impress ,and the program was dropped by Cat after a short time.

 

 

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Posted by alcomechanic on Monday, February 08, 2016 8:32 PM
We ran stationary, 538 ALCo’s built from 1947 to 1955 that burned natural gas, ignited by the diesel fuel.   These engines would develop the same horsepower on dual-fuel as on straight diesel.
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Posted by Morgan LeFay on Tuesday, May 01, 2018 12:31 AM
I don't care how old this thread it. I really don't. However, that being said, burning a kilogram of natural gas releases 55.5 megajoules of energy and burning a kilogram of diesel fuel releases about 47 megajoules of energy. Yet, the better way to power locomotives with natural gas is with combined cycle, natural gas-fired power plants and catenary.
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Posted by caldreamer on Tuesday, May 01, 2018 8:26 AM

Matt Rose executive chariman of of BNSF  said I believe it was last week that BNSF was mpt i LNG at this time due to slight difference in price between diesel and LNG.  He did not say that should that change that BNSF would not reconsider LNG, so I guess that that option is still on the table based upon price between the two fuels plus the cost of the retro kit.

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Posted by oltmannd on Tuesday, May 01, 2018 1:21 PM

caldreamer

Matt Rose executive chariman of of BNSF  said I believe it was last week that BNSF was mpt i LNG at this time due to slight difference in price between diesel and LNG.  He did not say that should that change that BNSF would not reconsider LNG, so I guess that that option is still on the table based upon price between the two fuels plus the cost of the retro kit.

 

Everytime a gap opens up between natural gas and coal/oil, the market adjusts and the gap closes up.  

One of the many benefits of electrifiation is being primary source agnostic - and being able to take advantage of whatever source is cheapest at the moment.

-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/

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