I will get around to hopefully asking a boiler tech later when they poke their head up....I am loosely acquainted with a couple of them elsewhere.
From what I know (very roughly), this kind of stuff is a bit of a dark art...that engineers (though we have "engine" in our name) cant really wrap their head around too well.
I watched drachfinel take on some of it....the area concerned I suppose is the fuel burner area...but this is very rough schematic of it:
View attachment 36138
Source vid (might be of interest to more ppl regarding boiler stuff and history):
I just think boilers this size have some preset issues with conventional ignitor...that is not very adaptable to different starting scenarios (so thats why you got lot of guys involved, looking and monitoring the port windows, ready to do small manual adjustment on the fuel feed rate at start etc).
I just remember a guy telling me about stuff involving a slow start process (you gotta do A, have A warm...to then do B....so B gets warm....and this is done sequentially to some letter way later)....since all the mechanisms governing it are all steam-run (so you got to do things very sequentially and slowly).
He is retired fellow of a (heritage) railway steam engine from my neck of woods in India....so they have to coax these engines in various ways each time....each one is a bit different now (with all kind of things they have made in the shop and retrofitted to help them over many decades). Different bits expand and compress a bit different.....different bits leak at different times while doing that etc. This all sets up the best practices in starting it up...and how to tinker and change those (on a day its grumpy and doesnt want to cooperate etc) if they dont work for some reason.
IIRC boilers in general (at large size) are this way as some pipe joints etc flex and fit slowly as temperature increased.
Startup procedure needs to consider things downstream (space and time wise) too ....it is bad if you get stuff (water) condensed there in certain joints (if you did hasty start up or shut down) and thats a nightmare to deal with big boilers (that you dont want to open up at any regular frequency)...especially if you want to use the system regularly in cycles.
So lot rests with the boiler techs doing the standard proven procedures like you say (if it aint broke, why fix it? etc)...including the ignition start-up (or large boiler action/setting changes in general).
Yup exactly! This philosophy extends even into aerospace in lot of ways that might surprise lot of people.
Not surprising at all.
Even with (large enough) diesel engines, stopping is a very serious issue here in Canada for example.
I worked at grain elevator company one time during my college years (summer job)....and the locomotives (shunters and also the bigger guys) there during winter would always be kept on idling...so they are ready to go...and not a cold lump of metal occupying a siding till warmer season lol.
Starting them up in dead of winter without a warm enough shed etc is just known to be too much issue heh.
Even during regular summer, they would just be left on idle a bunch where starting sequence would be too much of issue.
As the thermodynamic system gets even bigger (and involves a totally different working fluid material like water)...the "dark art" involved increases. Needs lot of people intimate with the system and its foibles.
convo chain might interest:
@AlphaMike @Joe Shearer @Gessler @Paro @Isa Khan @VCheng @Stuka Dive et al....in addition to regular Çay enjoyers already here.
