Application of Heat Recovery Loops for Improved Process Integration between Individual Plants at a Large Dairy Factory

Indirect heat transfer between individual plants at a large industrial site, such as at a large dairy factory, can be accomplished using a Heat Recovery Loop (HRL) operating at relatively low temperatures (20 - 50 degrees C). Direct heat transfer between plants is problematic because of the production schedule and frequent process start-up and shutdown that occur due to the need for regular cleaning. The dynamic operation of an industrial HRL at a large dairy factory is presented and briefly discussed. A HRL based on a set of stream data is used to examine the affect of heat storage capacity and HRL temperature on the amount of heat recovery. Storage volume can significantly improve the amount of heat recovery. The interface level in the storage tank is also modelled for different volumes and the resulting system is very dynamic and therefore good control needs to be incorporated into the HRL.