Study Of Thermal Energy Use At A Brewing Plant With Emphasis On Wort Boiling Process

Abstract

High energy costs and the need to reduce on CO2 emissions have brought to the fore the importance of reduction of energy usage in beer production. It is important that brewing process be analyzed to identify and evaluate opportunities for saving energy in specific process applications. This will determine savings on energy use and recovery, and process improvements required for implementation without negative effects on plant performance and final product specification. The brewing process is energy intensive, especially in the brew house, where wort boiling is the main heat consuming process. None of the energy audits done at the study plant has fully tackled energy use in this major energy consuming process in brew house. In this regard a study was made of the wort boiling process and related technology of the energy recovery systems used at Tusker Breweries, Nairobi. The study found that; (i) Atmospheric boiling should be avoided. Though this is driven by production demands and requirements, the energy that would have been recovered is lost. There is need for the company to strike a balance between the production demand and loss of energy. (ii) The wort pre-heater is critical equipment in the determination of the thermal efficiency of wort boiling process, and energy recovery and should never be bypassed. The results from the study demonstrate that significant savings of up to 20% of the daily steam consumption (equivalent to 93,380 MJ) can be made by efficient use of a pre-heater which leads to better utilization of the recovered energy from wort boiling. The study shows that by reducing energy and waste, variable utilities and production costs will be improved. Additional advantages resulting from efficient use of energy in the brew house are presented, whilst also making a significant reduction in carbon dioxide emissions required by legislation.