The challenge of integrating non-continuous processes – milk powder plant case study

Abstract

a b s t r a c tThe integration of non-continuous processes such as a milk powder plant presents a challenge for existing process integration techniques. Current techniques are generally based on steady and continuous operation which for some industries is not the case. Milk production varies considerably during the year as dairy cows in New Zealand are grazed on pasture. In this paper the potential for indirect heat transfer between the several plants using a heat recovery loop and stratified tank at a typical New Zealand dairy factory is investigated. The maximum amount of heat recovery is calculated for a range of recirculation loop temperatures. The maximum amount of heat recovery can be increased considerably if the temperature of the hot fluid in the recirculation loop is varied depending on which condition the site is operating under.

The green brewery concept – Energy efficiency and the use of renewable energy sources in breweries

“…Ideal storage sizing and management based on heat integration and renewable energy integration is seen as an important target for future simulation studies. This has been shown similarly for indirect storage tanks in other industries [3]. Also, existing storage tanks should be included in HEN design algorithms.…”

“…For breweries where rescheduling is a delicate issue due to the biological processes the adaptation or integration of storage tanks into the hot water management is a favorable option. Approaches for heat integration for batch processes including heat storage systems have been reported by several authors; however they are still not extensively studied [1][2][3][4]. The ideal choice of renewable energy resources for specific applications has been lately discussed by a number of researchers.…”

Heat integration of intermittently available continuous streams in multipurpose batch plants

“…The results for a case study at a modern plant show that 30% of the external heat demand and more than 10% of the shaftwork used in the plant can be further saved. Atkins et al (2010) investigated the potential for indirect heat integration at a dairy factory in New Zealand. The modified source/sink composite curves were used to estimate the maximum heat recovery and to determine the optimal temperatures of the stratified tank used for thermal storage.…”

Integrating heat recovery from milk powder spray dryer exhausts in the dairy industry

“…The average inlet air temperature prior to the air heater may be as high as 40 °C and the exhaust as low as 65 °C, which restricts the amount of heat that can be recovered. In order to improve the opportunity for heat recovery the entire production process should be considered [12,13].…”