This is an interesting concept :) While I would like to make a game out of it, I was put off by a few things:
- No support for expensive mode. Steel puddling produces 100 steel for 900 crushed Saphirite, but steel making via Angels requires 4000 which is too much of a discount.
- I feel it fiddles too much with the wood and steel processing chains (I play with AngelBobs and not AAI). I look at this as an extension to those mods and right now it doesn't feel well integrated.

Consider producing something like 'cast iron' instead of steel so you don't mess too much with progression but still maintain the same progression in your mod.

Otherwise I like the idea, especially the combustion byproducts part. If the AngelBobs integration smooths out I'll look to pick it up on my next playthrough.

Thank you for the feedback.

No support for expensive mode.

Yes... at the moment my mods dosen't take the expensive mode into account.
Sorry, I should mentation this in the description, because to change this will take some time and I wanted first to squish all other flaws and bugs.

Steel puddling produces 100 steel for 900 crushed Saphirite

in normal mode:
Angel steel:
- 4x crushed saphirite = 2 iron ore
- 24 iron ore = 24 iron ingot
- 24 iron ingot = 6 steel ingot
- 6 steel ingot = 60 molten steel
- 60 molten steel = 6 steel
- 24/2*4 = 48 crushed saphirite -> 6 steel
- 48/6 = 8 crushed saphirite -> 1 steel

My steel:
- 36 crushed saphirite = 4 steel
- 36/4 = 9 crushed saphirite -> 1 steel

You are right with angel my steel is too cheap.
I had somthing wrong in my last calculations it should be 12 = 1 steel
I will change my recipe to 24 crushed saphirite = 2 steel
Thanks for this hint!

...but steel making via Angels requires 4000...

on expensive with AngelBob I see only 100 steel = 1500 crushed saphirite? because the only two changes are: 6x crushed saphirite = 2 iron ore (2 crushed saphirite more) and you need 50 molten steel for 4 steel plates intead of 40 molten steel
How do you get to 4000 for 100 steel? (do I miss somthing?)

If the AngelBobs integration smooths out

It will with some more time... I hope! :)

All makes sense. The first steel recipe (made in a chemical furnace) is 8 iron plates (+ oxygen) -> 1 steel. It's very expensive and basically only to be used as a bootstrap, or when you cannot create more iron ore (which is typical in the AngelBob early game as there isn't enough copper demand). Agree the ingot route is the more common one and that your calculations are correct for that, but I don't feel the steam-era tech should eliminate that part of the AngelBob game. Just my opinion though.

No worries on the other stuff, you have a great start - it just needs a little more time :)

FWIW, I made a mod for myself that triples the cost, so puddling furnaces are less efficient than the first AngelBob steel recipie, preserving the tension of wanting to produce steel primarily from liquid steel but needing to keep up copper production to do so. I'm happy with it so far.

I'm going to look at trees and overall MJ values next. I spent some time playing with recipes and they look alright but want to do more of a playthrough and might tweak those also. I'll post here what I think. Of course you should balance the mod as fits with your vision :)