Approximately 25% of the usable energy of the fuel gas is released in the exhaust of the gas engine. This can be captured for cogeneration in a combined heat and power plant. This heat exits the engine at ~450oC as ‘high grade heat’, contrasting to ‘low-grade heat’ available from the generator cooling circuits. This high temperature and flow makes it well suited for utilisation in a waste heat boiler. The superheated steam produced in the boiler is typically available at 1-25 bar pressure for utilisation with nearby steam users. Steam boilers are utilised in a range of different gas applications with this being a popular solution for hospitals, sewage treatment works and industrial process plants.
Exhaust heat boilers are connected to the exhaust of the gas engine and can either be housed in an adjacent building or can be provided in their own customised container.