The Blazing Infuser improves Blazing Rods made by the Blazing Agitator. It consumes catalyst items to increase rod power, duration, or both.
After infusion, a rod can no longer help improve other rods in the Agitator. First make a good booster set, then infuse rods intended for fuel.
Catalysts for a full stack: redstone gives power, quartz gives duration, glowstone favors duration, dimensional shards improve both, and ghast tears or nether stars give large boosts.