Coke and fuel
as of 0.8.0
Every furnace in the mod burns solid fuel, and two different rules decide what it will take. A shaft furnace charges fuel into its column and prices it by carbon. A reverberatory furnace loads a fuel bed in its Firebox and prices it by burn temperature. Coke clears both, which is why the whole tier is built around it.
Carbon: what a shaft furnace burns
A shaft furnace meters production by the carbon it burns in front of its tuyeres, so a fuel is worth
what its carbon is worth. Fuel carbon comes from the fuel material role in
assets/iiex/config/materialroles.json, divided by the reference value of 2.
| Fuel | Role value | Carbon per unit |
|---|---|---|
game:coke | 2 | 1.0 |
game:charcoal | 1 | 0.5 |
| any other fuel granted the role with no value | 1, the fallback | 0.5 |
A grant with no value therefore carries charcoal's carbon rather than coke's. Charcoal is a legitimate fuel, and a charcoal course runs cooler and shorter than a coke course of the same height, because it carries half the carbon. Raw coal is not a shaft fuel at all: it is not in the role table, so the furnace does not recognise it.
Burn temperature: what a firebox takes
A Firebox burns plain fuel and asks mainly that it burns hot enough. Anything whose
combustibleProps declare a burn temperature of 1000 C or more is admitted, which lets coke,
charcoal, anthracite and the harder coals in and keeps firewood, peat and the rest out.
The machine that owns the bed can narrow that. The Puddling furnace, the Heating furnace and the Crucible furnace all refuse lignite by name, as too low-rank to carry a metallurgical heat: it burns at 1100 C and so clears the floor, which is why it has to be refused by name rather than by temperature. The Cornish Boiler keeps the plain rule and takes lignite, since raising steam is not metal work. The Coke oven narrows it the other way and takes only the coals that coke.
A bed holds one fuel at a time. It is drawn as 6 layers of 2 units per firebox cell, so one cell holds 12 units, and a furnace's bed is 12 units per firebox cell it declares. The puddling furnace has one firebox cell; the reheating furnace has two, so it costs twice as much for the same visible fill, though the player charges it with one click. Clicking the bed with fuel in hand spreads one deposit across every firebox cell of the owning furnace.
A lit firebox burns on a clock rather than by consumption: it runs 1200 seconds and then goes out. Pulling fuel back out of a lit bed is what puts it out early, and the floor is half the bed's own capacity.
The Coke Oven
Coal is not fuel here; coke is, and coke is baked from coal. Vanilla's sealed coal pile does this one pile at a time. The Coke Oven Core anchors a two-chamber beehive oven that does it at the scale an ironworks needs: six cells of coal per chamber, two chambers to a bank sharing one wall.
| Quantity | Value |
|---|---|
| bake time, per chamber | 3600 seconds |
| coal that survives as coke | 0.9 of the charge, truncated |
| cells per chamber | 6, at 12 units each |
| coal that cokes | bituminous only |
| light temperature | 400 C |
Truncation matters at the cell: a 12-unit cell at 0.9 yields 10 units of coke, an effective 10 in 12, which is still well above vanilla's 0.75 for bituminous coal. Anthracite has no coking rate in vanilla and does not coke here either; lignite is excluded by ruling. The accepted list lives in config, so a modded coal can be admitted without a patch.
Coking is destructive distillation: the coal has to be heated out of contact with air. A chamber is sealed only when both its closures are shut, the Charge Lid in the crown above it and the Charge Door at its front. A chamber standing open bakes nothing, however long it is left. Opening a lid mid-bake pauses that chamber and shutting it again carries on from where it stopped; the clock is not reset.
The two chambers keep their own clocks, so one can be drawn and recharged while the other bakes. Charging is still an oven-wide gesture: one deposit spreads across the firebox cells of both chambers, not one.
Step by step
- Build the oven up from its Coke Oven Core, then shut both doors and both lids.
- Open a chamber's door and right-click the bed behind it with bituminous coal. The whole chamber fills from one interaction, charged per cell.
- Shut the door and the lid over that chamber.
- Light the oven.
- Read the core: it names each chamber and how far through its bake it is.
- When a chamber reports its bake done, open its door and draw the coke.
What goes wrong
The chamber never progresses. It is not sealed. Both the lid above it and the door in front of it must be shut. The core says which chamber is open rather than sitting there quietly doing nothing.
The clock keeps resetting to zero. The bed holds a coal that does not coke. Charcoal and coke are not coal, anthracite will not coke, and lignite is refused; a chamber whose beds hold none of the accepted coals has its clock zeroed every tick.
A hopper over the oven does nothing. The Tall Hopper charges shaft columns, and a coke oven has none. Click the chamber bed instead.
The blast furnace refuses what came out of a campfire. Raw coal has no fuel role, so a shaft furnace does not see it as charge at all.