On vacation, we took a dinner cruise / harbor tour boat at Duluth, Minnesota. When talking about a 1000 foot laker ore boat, the narrator on the tour said it had 4 -20 cylender EMD diesel engines, providing 14,400 hp. That seemed familiar enough. Then, he said the heavy white smoke coming from the laker was the captain running the auxiliary motor that heated up the Bunker C oil used to power the diesels. If the Bunker C oil were not preheated to something like 200 degrees, he said it would be too thik to even flow into the engine.(?) Really?
I’ve heard of Bunker C (really thick, heavy oil) used for boilers in ships, UP turbine locomotives, and possibly SP cab forward steamers. Is it really used in EMD diesels?
Back about 1980 there was a lot of interest in burning bunker C fuel instead of no. 2 because of cost mostly overseas and EMD did a lot of experimenting with it with mixed results. Yes the engines could run on it but the maintenance costs went way up. They even equipped a Sonat Marine tug with all the equipment required which includes a centrifuge, heaters, various pumps and extra fuel filters. To operate this equipment requires extra engine room staff, probably why they never got around to actually using it . There are units overseas that did use bunker C fuel including a Glomar drill ship. On the engine it is required to use chrome plated liners with the appropriate piston ring set. On the great lakes there are several 1000 ft ore carriers that have EMD engines but I think they all run on no.2. American Steamship besides having ships with EMD engines has a few steamers and a boat with Pielstick engines that do use bunker C. They also have large engine room staffs. Bunker C has about 10 times the sulfur content of no.2 and with EPA fuel regulations requiring low sulfur in fuel there is no price advantage in using bunker C
According to a WSJ article last week the heavy oil price is almost at the price of west Texas light sweet and has caused refinerys built to use the heavy oil in a bind and not able to get enough either. Bunker C is disappearing and I believe most of the oil burner steamers at the festival used #2 diesel. .
Of course one of the most famous uses of Bunker C fuel in the transition to post-steam era of motive power was by Union Pacific’s fleet of Gas Turbines, which were specifically designed to use it…the increase in the price of Bunker C due to it’s usage as feedstock for the plastics industry throught the 60’s made the turbines lese-and-less economical…
Along with the more famous case of UP turbines, didn’t SP experiment (maybe in the late 1950s) with burning heavier oil in some of its diesel locomotives?
As I recall, the experimental engine(s) had a small tank of DF2 along with a large heated tank of bunker fuel. The DF2 was for starting the engine, and for leaving in the fuel system when shutting down. The large tank of bunker fuel had to be kept very warm, of course, and was not to be used unless it was.
A big problem was with making SURE that an engineer or hostler switched back to light fuel and did NOT leave the heavy oil in use when shutting down the engine. If a diesel cooled off with the heavy oil in its injection system, it reportedly was worth your life to clean it out. Bad mess!
Hope I’m not getting too off topic but what is the difference between Bunker C and the fuel used by modern “heavy fuel” marine engines found on oceangoing tugs and large merchant ships? IIRC, the US Navy at one time favored O.P Fairbanks Morse engines in their tug fleet and these mostly burned Bunker C…
Essentially nothing. Bunker C is roughly identical to #6 heavy fuel oil, which is the most common. It’s also frequently called residual oil, or just “resid.”
I sincerely doubt he knew anything about the topic. #6 also called bunker C does not burn unless you atomize it with steam into very fine droplets. When it does burn it gives off dark gray or black smoke subject to the amount of atomization. I burned that stuff in a steel mill for four years and never want to see it again as long as I live. I had to start heating the oil tanks in July to have it ready by October when it was needed. I was happy if I could get the tanks to 260 deg. F. If the choice is to do without heat or burn that stuff I would do without heat. I can’t imagine any way you could put it in a diesel and have it self combust due to pressure from a piston.
While you are correct in regards to high speed and medium speed diesels in appplications such as trucks and locomotives,large (in some cases house sized)low speed marine diesels mostly operate on heavy fuel.
Couple of specs from one of the larger Wartsila diesels: (approximate) Cylinder diameter 32 inches, Piston stroke 11 feet. Operating RPM range 62-82. definitely not an EMD 645
In the early 1960’s Union Pacific converted their 300 class GP9 locomotives with turbocharged engines (making them essentially a GP20) and modified the fuel tank to carry bunker C fuel by adding loops of pipe that carried engine cooling water through the tank to heat the bunker C. Small “saddle tanks” were added to the top of the fuel tank for #2 diesel to run the engine after start to warm up the main tank of bunker C then the engine was switched to bunker C for normal operation. The biggest problem was if the engine was shut down without switching back to #2 diesel before shutdown. If the engine was shutdown with bunker C in the fuel lines and injectors, a complete disassembly of the fuel system was required to wash out the bunker C. Union Pacific did run the locomotives on bunker C for a few years before giving up and letting the turbine locomotives finish burning the remaining bunker C fuel that the railroad had contracted for when bunker C was the fuel burned by oil burning steam engines
I wonder if routing the exhaust through the tank holding the Bunker C would also have helped. Maybe it was not as safe. I had regularly seen tractor-trailers on the NY Thruway during the 1980s that had their exhaust stacks routed through the trailers in the wintertime.
Speaking of steam engine fuel, the Extreme Trains show said that on present-day excusions the UP 844 steam engine burned used a mixture of used engine oil and waste fuels for its boiler.
A not at all uncommon practice among historical and tourist railroads.
But there were some problems when some oil recyclers decided it was an easier way for them to get rid of environmentally difficult chemical additives in the oil. Both US and Canadian environmental authorities have stepped in to more thoroughly control what is being burned.
As someone on another forum once observed, when you force any hydrocarbon through a nozzle at 150 PSI into a firebox it will burn.
I’ve been on ferries with that general type of engine (cylinders big enough to crawl through). When they rev up, it’s foom…foom…foom…foom…foom…foom…foom…foom…foom
“tleary01” raises an issue that begs the 3-questions appearing below.
In the post steam locomotive era, did anyone make a locomotive steam generator that burned no. 6 fuel oil or Bunker C? I can conceive of a passenger diesel whose prime mover would run on no. 2 fuel oil, and whose boiler would run on no. 6, but alas I never saw such an arrangement. But then again having to inventory and distribute two different grades of fuel oil when the price for diesel fuel in the 1950s and 1960s was bordering on dirt cheap may have made this idea impractical.
What did the PRR passenger electrics burn to fire their boilers?
What did the MILW passenger electrics burn to fire their boilers?