I have a high pressure boiler with a solid fueled firebox.
I have a dsu of wood I connect pipes to the boiler and it cannot keep up. Is there a way I can fuel my firebox so it can keep up?
Either use something faster than "pipes" (not sure if this is meant as BC pipes, if so then you can speed them up with better engines, autarchic gates etc, but nevertheless you should consider a better solution like itemducts, routers, whatever depending on pack/version). But indeed consider putting the wood through a coke oven/furnace first to make it into charcoal to multiply its fuel value many times.
You really need to give more details when asking for help like this. Really dont know what kind of "pipes" you are using, what pack you are on, which MC version etc. Boilers have changed dramatically over the years and loads of alternatives to BC pipes are available in new packs.