Operational have installed many oven heat recovery systems to harness the waste heat in the exhaust gases leaving large travelling bread ovens in plant bakeries.
The exhaust air leaving these ovens varies from 120oC up to approximately 300 oC and often contains copious amounts of moisture due to the steaming of bread at the inlet of the ovens. Accordingly, large amounts of sensible and latent heat are available for recovery and re-use throughout the Bakery.
Many challenges have been overcome such as the fouling of heat exchangers from the ‘tincol’ oils used in the production process to the corrosion caused by the products of combustion.
The waste heat recovered from the oven exhaust gases is transferred into a low/medium pressure hot water ring main from where the recovered heat is transferred to a number of energy users throughout the bakery.
Typically, this recovered heat would be used to heat the initial and final provers, the hot air blast systems for skinning of the dough pieces and for the pre-heating of make-up water to the steam boilers, the basket washers and calorifiers.
Typical return on investments of between 2 and 3 years is achieved.