Hydrogen recycling - a way to improve the efficiency of HPH®-bell-type annealing furnaces

Hydrogen is used around the world as a protective gas in modern bell annealing furnaces and hydrogen costs represent a significant proportion of operating costs. This article describes a method for recycling of hydrogen in bell annealing resulting in significantly reduced operating costs. The integration of the hydrogen recycling system with the bell annealing furnaces is presented and operating costs and environmental benefits are assessed. The system can be retrofitted to existing bell annealing installations and has potential for other applications where hydrogen is used.