Thermal and exergoeconomic analysis of a dairy food processing plant

The dairy processing industry in India, on an average basis, involves an extensive amount of thermal and electrical energy consumption, i.e. 2.51 × 105 kW MT−1 and 1.44 × 105 kW MT−1, respectively, for an installed milk food processing capacity of 1.21 × 105 TPD. However, energy consumption spectrum depends upon the level of automation along with better utilisation of utility resources. The global ultra-high-temperature (UHT) pasteurised milk trade was valued at € 52.29 billion in 2012 and is expected to reach € 114.38 billion by 2019–2020. In the present work energy, exergy and exergoeconomic evaluation of ultra-high-temperature milk pasteurisation plant have been considered. The overall energy efficiency and efficiency pertaining to executable potential of energy in UHT Milk Processing Unit were reported to be 86.36% and 53.02%. The specific exergy destruction and specific exergy improvement potential were estimated to be 219.23 kJ kg−1 and 137.60 kJ kg−1, respectively. The highest possible retrievable exergy potential of the plant was associated with heating coil, i.e. 158.98 kW, followed by homogeniser (54.62 kW), which pinpointed towards the possibility of huge technical improvement. The processing cost was enumerated to be highest for heating coil (rk: 38.35%) followed by regeneration-1 (rk: 23.40%). Further, the total operating cost rate associated with thermodynamic deficiencies of subunits was estimated to be highest for heating coil (4859.82 € H−1) followed by regenerator-2 (1264.88 € H−1) and homogeniser (1187.14 € H−1). The broad survey of thermoeconomic indices of subunits indicated that the level of exergetic destruction was far more on higher side.