HRSG Pinch Point & Approach Temperature Calculator
Determine evaporator pinch temperature difference, economizer approach margin, high-pressure steam generation, and boiler exhaust stack temperature.
Gas Turbine Exhaust & Steam Cycle
HRSG Heat Transfer & Steam Generation
Recommended Tools & Equipment
Tested hardware and components for high reliability
HRSG Temperature Profile & Pinch Point
In a Heat Recovery Steam Generator (HRSG), the hot exhaust gas from a combustion turbine transfers heat successively to superheaters, evaporators, and economizers. Because boiling occurs at a constant saturation temperature ($T_{sat}$), the temperature difference between the exhaust gas and steam reaches a minimum bottleneck at the evaporator outlet, known as the pinch point.
Economizer Approach Temperature
To prevent premature steaming inside economizer tube bundles (which can cause water hammer, thermal shock, and severe vibration), the water exit temperature is kept $5^\circ\text{C}$ to $10^\circ\text{C}$ below the drum saturation temperature. This safety temperature delta is the approach temperature ($\Delta T_{app} = T_{sat} - T_{eco,out}$).