LDG gasholder
24 hours of a BOF-gas holder with two converters: how much LDG is flared under manual operation and with a gas management system.
Simulator developed by José Geraldo da Silva Moreira · Energy-efficiency lab
LDG gasholder: 24 hours with two converters
Each converter recovers LDG for ≈12 min every ≈55 min at ≈110 thousand Nm³/h; blows can overlap (up to ≈220 thousand Nm³/h). The boilers burn up to 60 thousand Nm³/h. From 14:00 to 17:00 one converter is down.
Manual: the operator reviews boiler load every 2 h and reacts to level alarms with ≈15 min delay. GMS: uses the blow schedule of both converters (next-hour forecast) to adjust the boilers and keep the level away from the limits, within the ramp rate. The level has no loop of its own; automatic action only happens at the limits. High level: recovery stops and LDG goes to the steel-shop flare. Low level: the holder outlet closes and the boilers burn natural gas.
LDG flared · manual
LDG flared · GMS
Boilers without LDG
minutes at minimum level · manual → GMS
Annualized value
natural gas avoided
Gasholder level (%)
ManualWith GMS▼ LDG to flare (manual)yellow band: converter down
LDG recovery and boiler load (thousand Nm³/h)
Recovery (2 converters)Boilers · manualBoilers · GMS
What to watch
- Gas flows in and out of the holder on its own, by balance: the level is the running sum of (recovery − consumption).
- With boilers held at low load “just in case”, the holder stays full and any overlapping blow ends up flared.
- With the blow schedule, the GMS adjusts the boilers ahead of recovery and keeps the level away from the limits: same volume, no construction.
Simplified teaching models with order-of-magnitude illustrative values. Do not use them for design or operating decisions without validation against plant data.