The document discusses using user variables, scripts, and triggers in KBC software to iteratively estimate flue gas composition from hydrogen content in coke. It proposes creating user variables to store the hydrogen target and estimated flue gas CO2, then using scripts and triggers to iterate the CO2 calculation until the target is met. Diagrams show the logic flow and how triggers would solve the FCC model on changes to drive iteration. The conclusion states that user variables and scripts add functionality, and triggers require practice to setup correctly.