Castings - Waste Heat Recovery Project
The client, a large engineering and castings company was looking at how they could reduce their high energy bills through heat capture from two 9t, and two 4t cupola induction furnaces. The investigation was conducted at high level providing a snapshot into the potential for heat capture. However, the challenge wasn’t in the heat recovery process, it was in its application. Catalyst needed to understand how efficient the current casting process was to help provide an accurate baseline and required data on fuel to air ratios, burner temperatures, pressure details as well as an understanding of furnace losses including.
The stoichiometric,or on-ratio combustion was producing higher temperatures than required and was originally done deliberately to obtain certain operating benefits. However, it was found that the burner system was out of adjustment also, creating higher temperatures that was required. Excess air due to negative pressures was also lowering the furnace efficiency due to the draft effect of hot furnace stacks. Designing an efficient heat recovery system is not difficult but determining the feasibility of a heat recovery system is. Fluctuating utility prices and changing regulations complicate payback calculations. However, the science and technology of heat recovery is well developed and the skill-set required lies in the application.