Waste Heat Recovery from Metal Casting and Scrap Preheating Using Recovered Heat

AbstractIn metal casting, after solidification of the molten metal in the mold cavity, the knocked out casting has heat energy stored it and is wasted into atmosphere as the casting cools down in the shop floor. If this heat energy can be absorbed by the raw materials by a suitable arrangement, it will reduce energy consumption during melting, resulting in savings in economy and environment. This paper discusses an innovative approach to implement such a methodology. In a basic set up, when this preheating was achieved, the scrap was found to take 2.83% less energy than it would take to melt without this preheating set up. This technique has been improvised by keeping aluminum powder in between the scrap and the hot casting to have better heat recovery, resulting in an increase of heat recovery to the tune of 5.7%. When this savings are applied to global castings produced, which run into millions, the total energy and emissions saved amounts to a substantial figure. The calculations indicate energy savings as high as 419 GWh, which translates roughly to Rs 377 crores a year for Indian foundries in one year