Utility Optimization in a Brewery Process Based on Energy Integration Methodology

This paper presents a methodology aimed at improving the energy efficiency of a brewery applying process integration techniques. The different steps of the analysis are presented. The first step is the identification of the process energy requirements and the corresponding heat loads, which allows the definition of the process hot and cold streams. The Pinch Analysis of the brewery reveals a heat recovery potential of 36% by improving the heat exchanger system. In order to satisfy the minimum energy requirements, optimal energy conversion technology configurations are calculated, taking into account economic and environmental criteria. The integration of suitable utilities is considered (cogeneration engine combined with heat pumping and refrigeration systems) and the interaction between them is analyzed. In addition, a thermo-economic optimization is performed in order to determine the optimal heat pump operating temperatures. The results show the opportunity to reduce by 36% the brewery heating bill and by 44% the CO2 emissions through the set up of an optimized utility configuration when compared to the current one. In addition, the optimal integration shows that the cooling water consumption of the refrigeration can be suppressed and appropriately be replaced by a heat pumping effect. The comparison between French and German conditions shows that contrasting results can be obtained due to the different economic and energy supply configurations. The process system analysis shows that when considering the recovery of the plant organic waste, bio-methane can be produced and valorized in the cogeneration engine. In that case, it is demonstrated that the process can become self sufficient in terms of energy.