Performance enhancement of marine inert gas generator with combustion

Résumé

The heat generated in the combustion inert gas generator (IGG) is usually discharged with flue gas cooling water. This paper proposes a system for recovering part of the heat generated in the IGG and using it in an absorption chiller for advanced cooling of the inert gas. The thermodynamic analysis showed that for an IGG consuming 240 kg/h of marine gas oil, 132 kW can be recovered to drive a lithium bromide-water absorption chiller, which can cool the inert gas down to 15°C, a temperature at which the water vapor content of the inert gas is 12.79 g/m3, much lower than if the inert gas is cooled only down to 50°C (82.5 g/m3) as it is done in most IGGs. By recovering waste heat, the quality of the inert gas is improved (humidity is reduced) without additional energy consumption.