Exergy analysis and boiler efficiency enhancement of a dairy plant for milk and derivative production

This paper presents an exergy analysis of a dairy plant in Beni Mellal/Khenifra, examining milk and derivative production. Exergy destruction rate and exergetic efficiency are calculated for each component of each process. The results indicate the boiler as the primary contributor to exergy destruction with a value of 6,402.40 kW, followed by the sterilisation line, the refrigeration system, the yogurt line and finally the pasteurisation line with percentages of 87.6%, 6.12%, 2.9%, 1.76%, 1.61%, respectively. To reduce boiler exergy loss, economiser design is proposed to recover waste heat. The design considers parameters like tube dimensions, count, passes, shell dimensions, and baffle thickness. The objective is cost-effective design with maximum performance. Optimisation led to substantial fuel savings, the economiser's initial cost was approximately $24,968 with payback period of only three months.