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.
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/)
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.
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
f45gnbnThink 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
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'.
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.
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.
carnej1 I googled around a bit and found that in fact there are Gas turbines on the market for applications such as marine propulsion of high speed vessels and backup power that can meet Tier IV and do not need steam injection to do so. GE is offering Tier IV compliant gas turbines for Marine usage with no steam system. They mention "Dry Low Emissions"(DLE) burner technology as the key. Cat subsidiary Solar Turbines calls their modified burner system SoLoNOx...
I googled around a bit and found that in fact there are Gas turbines on the market for applications such as marine propulsion of high speed vessels and backup power that can meet Tier IV and do not need steam injection to do so.
GE is offering Tier IV compliant gas turbines for Marine usage with no steam system. They mention "Dry Low Emissions"(DLE) burner technology as the key.
Cat subsidiary Solar Turbines calls their modified burner system SoLoNOx...
I would be very surprised if there wasn't a means of meeting Tier IV standards without steam injection, as it does add a fair amount of complication as well as being a "no-go" issue for a lot of customers. I brought up steam injection as a potential benefit of using turbines as it lowers SFC as well as cooling the exhaust. The latter point is in respect to stories aboout what happened when one of the UP's big blows was stopped below a bridge. OTOH, it is quite possible that the liabilities of using steam injection would outweigh the benefits for locomotive applications.
- Erik
All of y'all that are working on CNG for locomotives -- Ross, that specifically includes you! -- need to watch this a couple of times. And perhaps scale the effect appropriately.
This would not happen this way with LNG.
A recent example of the problem with Natural Gas powered vehicles, in this case a truck.
http://www.nbcphiladelphia.com/news/breaking/Trash-Truck-Fire-Trenton-366596361.html
erikem carnej1 I don't know about putting a steam bottoming system on a gas turbine locomotive (though I have seen a patent for a combined cycle locomotive). I seem to recall reading somewhere that there are also liquid agents similiar to Urea/SCR (maybe the same) that are used in turbine applications to control emissions. Steam injection, not steam bottoming. This was stirring up quite a bit of interest in the 1980's - I have a 27 year old flyer about the Allison 501-KH turbine showing a 40% increase in output power and a 13% decrease in specific fuel consumption. NOx reduction comes from the steam cooling the combustion gases, much the way that EGR works in piston engines. The downside is the necessity of dragging the water along.
carnej1 I don't know about putting a steam bottoming system on a gas turbine locomotive (though I have seen a patent for a combined cycle locomotive). I seem to recall reading somewhere that there are also liquid agents similiar to Urea/SCR (maybe the same) that are used in turbine applications to control emissions.
I don't know about putting a steam bottoming system on a gas turbine locomotive (though I have seen a patent for a combined cycle locomotive). I seem to recall reading somewhere that there are also liquid agents similiar to Urea/SCR (maybe the same) that are used in turbine applications to control emissions.
Steam injection, not steam bottoming. This was stirring up quite a bit of interest in the 1980's - I have a 27 year old flyer about the Allison 501-KH turbine showing a 40% increase in output power and a 13% decrease in specific fuel consumption. NOx reduction comes from the steam cooling the combustion gases, much the way that EGR works in piston engines.
The downside is the necessity of dragging the water along.
UP's gas turbines used Bunker C (heavy) oil. They found that the turbines used as much fuel ideling as they did in run 8. As far as dual fuel diesle locomotives go, there is very little if any change to the injection system necessary. With today's computerized control systems it seems to work pretty well. The BNSF is training there people how to handle duel fuel locomotives.
A
erikem carnej1 I do wonder if Natural Gas fueled turbines would meet Tier IV standards, are they similiar in emissions to a Dual Fuel Diesel/Gas engine? Good question, don't have a definite answer on that one. OTOH, gas turbines run lean and thus should have low CO and unburned HC in the exhaust, smoke (particulates) hasn't been an issue for the last few decades, which leaves NOx. The NOx can be reduced with steam injection, which also improves efficiency. The exhaust heat can be used to generate steam, which should significantly reduce the exhaust gas temperature. - Erik
carnej1 I do wonder if Natural Gas fueled turbines would meet Tier IV standards, are they similiar in emissions to a Dual Fuel Diesel/Gas engine?
I do wonder if Natural Gas fueled turbines would meet Tier IV standards, are they similiar in emissions to a Dual Fuel Diesel/Gas engine?
Good question, don't have a definite answer on that one. OTOH, gas turbines run lean and thus should have low CO and unburned HC in the exhaust, smoke (particulates) hasn't been an issue for the last few decades, which leaves NOx. The NOx can be reduced with steam injection, which also improves efficiency. The exhaust heat can be used to generate steam, which should significantly reduce the exhaust gas temperature.
Oops, that is what happens every time I try to rely on my old memory. Time does a number on us all.
erikem I'd wonder if the best solution for a natral gas locomotive would be to stick a couple of gas turbines in the carbody. Having two would allow for one to be shut down for extended runnng at run 4 or less. The low weight of the turbines could also allow for the installation of a battery such as GE was working for hybrid locomotives.
I'd wonder if the best solution for a natral gas locomotive would be to stick a couple of gas turbines in the carbody. Having two would allow for one to be shut down for extended runnng at run 4 or less. The low weight of the turbines could also allow for the installation of a battery such as GE was working for hybrid locomotives.
The Russians thinks so; GE ,Progress/EMD and the North American Class 1's instead want dual fuel versions of existing locomotives using more standard (for locomotives) engine technology.
Railpower was trying to market a CNG powered road locomotives a few years back..
BNSF has also looked at fuel cells for power.
http://www.apta.com/mc/rail/previous/2010/Papers/Demonstration-of-a-Hydrogen-Fuel-Cell-Locomotive.pdf
EuclidThat is a good question as to whether the existing diesel engine can be made to burn natural gas fast enough to get the rated diesel horsepower. If it can't, could a new natural gas engine be developed to fit into the same carbody and deliver the same horsepower as a diesel engine? Maybe that is the plan, but I don't know if it is.
Can't and won't, from first principles.
Natural gas as you know has lower heat content, so you're going to 'equal' the heat release per stroke only two ways: increase displacement, or increase engine speed.
The latter is impractical for a variety of reasons, starting with reliable engine construction itself and extending to the connected alternator, which is not really designed to spin faster in service. That leaves increasing bore, which requires different power assemblies and increases the piston mass, or stroke, which screws up its own set of things like peak inertial load and rod angularity. Don't expect either of those 'just' so you can burn natural gas.
Meanwhile, if I'm not mistaken, the degree to which you can pressure-charge a natural gas engine is greatly restricted vs. what a diesel that meters a liquid fuel into an above-critical air mass. So cranking up the boost isn't likely to get you 'there', either, even if higher boost pressures could be accommodated in these large engines without crippling increase in weight, or else occasional bomblike 'spontaneous disassembly events'. Injecting LNG as a 'critical liquid' is an interesting possibility ... but as someone on RyPN recently said in a different context, if you put this on a unit "you can find me in a trailing unit checking the dates on the fire extinguishers"... Laser ignition is a bit more promising than spark ignition as it gives you the ability to initiate polynucleate combustion (like what happens in good diesel direct injection) but the power to generate the necessary laser 'kernels' within the cylinder is pretty high, and has to be derived from some source powered by the engine.
The situation with a high-speed engine like the C175 or QSK may be different. Cat has built spark-ignition natural-gas-burning engines of locomotive size for many years -- there was one on the crew tank at Princeton in my father's day. Presumably there is better technology, although I cheerfully defer to people like entropy who have distinctive competence and experience with recent Cat or Cummins tech.
If you want to maintain the engine as a 'dual-fuel' construction, assume it will be derated (similar to how motor vehicles are derated when converted to burn CNG or LNG) and almost certainly assume that the engine will continue to require a small percentage of liquid fuel, injected through the 'regular' system, as the necessary promotion and ignition source.
There are other technologies to burn cryomethane that ought to produce higher horsepower within the confines of a regular carbody. Some of this stuff may or may not still be classified, but I suspect that just as the whole market for brazed titanium airframes never developed, the whole market for high-output pulse detonation engines that burn liquid CH4 has largely vanished. That's a shame, because what I've seen of the technology was fun. But if free-piston engines failed largely because of the tract noise ... just imagine the situation with shockwave compression ignition in each cylinder 30 or more times per second...
From what I know about the earlier ECI conversions of the BN SD40's is that the engines are "Dual Fuel" that is to still be compression ignition they squirt in 10% diesel fuel which burns igniting the gas charge. The other modifications are that the compression ratio was reduced fro 14.5 to 12.5 to prevent detonation of the gas and they also put in a separate aftercooling system like the new engines have, to try to regain the lost power from using NG.
ECI has designed a 100% gas engine that has spark plugs instead of fuel injectors but to make a stocimetric mixture they have to use a throttle like your car has. Of course now its not a diesel.
Feasability aside, I think there is a bit of prudent wait-and-see on the part of the railroads. Currently there is a glut of natural gas, but as fracking production has been somewhat curtailed recently and a lot of power plants have switched from coal this cheap gas won't last forever and may be gone soon.
This should keep you busy for a while.
http://www.arb.ca.gov/railyard/ryagreement/112807lngqa.pdf
Norm
Murphy Siding Rather than the gas making the locomotive perform at only 60%-70% of the horsepower it would produce with diesel fuel, I picture the technology being tweaked to force 43%-67% more gas into the engine and retain the same horsepower. If gas use cut the available horsepower by 30%-40%, I couldn't see the railroads having any interest at all. Another factor may be related to working for cleaner emissions. Maybe the gas powered locomotive is Tier whatever compliable already?
Rather than the gas making the locomotive perform at only 60%-70% of the horsepower it would produce with diesel fuel, I picture the technology being tweaked to force 43%-67% more gas into the engine and retain the same horsepower. If gas use cut the available horsepower by 30%-40%, I couldn't see the railroads having any interest at all. Another factor may be related to working for cleaner emissions. Maybe the gas powered locomotive is Tier whatever compliable already?
That is a good question as to whether the existing diesel engine can be made to burn natural gas fast enough to get the rated diesel horsepower. If it can't, could a new natural gas engine be developed to fit into the same carbody and deliver the same horsepower as a diesel engine? Maybe that is the plan, but I don't know if it is.
CShaveRR The gas is under pressure, so it weighs plenty. I'm not sure whether we're talking CNG or LNG here; it looks like they're liquefying it by cooling it, so the cooling apparatus also weighs a bit. Still, it's one car--shouldn't always be the tipping factor.
The gas is under pressure, so it weighs plenty. I'm not sure whether we're talking CNG or LNG here; it looks like they're liquefying it by cooling it, so the cooling apparatus also weighs a bit. Still, it's one car--shouldn't always be the tipping factor.
Thanks to Chris / CopCarSS for my avatar.
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