Cleaner flue gas and energy recovery through pinch analysis

The paper addresses the problems of cleaner energy generation in industrial applications. Its aims further flue gas energy recovery accompanied with additional environmental impact. It shows how the widely accepted flue gas temperature of industrial coal fired boilers can be lowered substantially without increasing the risk of back-end condensation. This is possible through dehumidification and partial absorption of the flue gas in a packed-bed economiser system by circulating water. Different design contact economiser systems (CES) are presented and compared. Pinch principles are deployed for targeting, design and operation-guiding purposes, balancing the heat and mass transfer in a second generation CES of parallel type. The results are expected to make these systems more sophisticated and more suitable for industrial applications. They open the door for valuable boiler efficiency improvement and generalisation of methodology for simultaneous management of energy and water resources.