As long as cryomethane was being used as a potential fuel for gas turbines or combined-cycle, its discussion would apply here, and the work of Iden’s NGFT group continues to be … potentially … applicable to such locomotives were they to be developed. I agree that the subject of LNG-fueled compression-ignition locomotives should be moved to a new thread, probably in ‘Locomotives’, or one of the older threads on LNG/CNG locomotives be resuscitated for the purpose…
One little note that would also be applicable in a somewhat different sense to turbines:
From the report:
“In the [compression-ignition] engine’s power assemblies (cylinders), diesel fuel, which ignites under high compression, is used to ignite the natural gas. (“All of the technologies current being promoted pass gaseous methane, not LNG, onto the dual-fuel locomotive and into the engine cylinders,” says Iden. “Technology does not currently exist to inject LNG directly into engine cylinders and properly combust it.”) This method provides some operational flexibility, depending upon the LNG/diesel ratio. High pressure direct injection (HPDI, at 5,000 to 8,000 psi), and low pressure (125 psi) fuel delivery methods are being looked at. HPDI fuel delivery requires port or direct injection at the cylinder; this method is purported to save anywhere from 40% to 60% in fuel costs.”
I would note that the critical pressure of methane is under 675psi under otherwise standard conditions, so under HPDI the feedstock can be kept in liquid phase through the full required heating, and potentially metered through the same general approach used on the Enginion steam motor “zero emission engine”. I also wonder whether laser ignition (w
I don’t see how a straight electric would be more efficient since the aforementioned loss of energy would take place at the power plant instead of on the locomotive plus there would be additional losses in the movement of electrical energy through the catenary.
Use if fuel in any large power plant is always far more efficient than use on a locomotive. Consant speed operation at the most efficient speed, greater efficiency in cooling, eetc. Doesn’t matter whether you compare diesel vs. diesel, steam vs. steam, the larger fixed plant is always more efficeit than the moving small plant. And this difference in efficiency is somewhat greater than the loss of efficiency in transmission, even in the worst cases.
To amplify on what Dave wrote, a combined cycle gas turbine station can reach 60% efficiency. The best diesel engines are running slightly over 50% and those are ship sized units running at constant speed.
In anything moving on earth, the cost to “put that body in motion” is higher than keeping it in motion to a great degree. Maybe its time to think outside the train engine, and climb on board an aircraft carrier. Fixed Steam catapults for Train engines, at stations could save HUGE amounts on other fuels and the various means of creating the steam could be better controlled. Long distance passenger service could benefit the most, but having a boost for freight couldn’t hurt. Intermodal maybe?
Since the Jet in NYC landed safely in the Hudson River, a huge amount of research has been done on jet engine “blades” ~vs~ Geese. This involved many tests with frozen turkeys ( no lie) and now there are blades made from carbon Fiber that Stand up to the Turkeys and do NOT vibrate after impact. I do NOT know their heat limits but I have a friend who makes the blades they use in the 787’s now. This technology may be something to throw in the mix.
On the CNG and LNG thought. Landfills can and do produce Natural gas. There is a cost to Filter out metals,water, and then you have your average weak natural gas. Natural gas from mining is more pure, but still needs to be purified, water and hydrocarbons gone. Once you have it purified, it takes energy to Compress it into CNG. To make LNG requires even more energy to bring that to a very low temp, (−260 °F) . In Tankers the LNG is at low pressure. LNG has about 2 and a half times MORE energy than CNG, but still only about 62% of Diesel fuel… Trains running on LNG are a b o m b and would require many many tenders as seen in the CNG tests. BaltACD is correct, its not going to fly. If any of you have been near a port, or in the navy, you know what happens when a LNG tanker comes to port, the CG and or Navy and harbor patrol CLEAR the harbor…MOst the LNG in the US is imported due to cost to make it. Its not as cheap as its been touted. Interesting topic
I’m going to assume that the first part of the last post is an early April fool’s joke although there have been proposals to do something similar in concept to what you are suggesting using electromagnetic linear induction motors (which, to tie it together is the same technology that the US Navy is trying to replace Steam catapults with)…
Not fired with coal or oil. Nothing new fired with coal will be allowed in today’s political climate. Oil is too expensive with low efficiency systems like small steam turbines.