Conventional and Advanced Exergy and Exergoeconomic Analysis of a Spray Drying System: A Case Study of an Instant Coffee Factory in Ecuador

Abstract

Instant coffee is produced worldwide by spray drying coffee extract on an industrial scale. This production process is energy intensive, 70% of the operational costs are due to energy requirements. This study aims to identify the potential for energy and cost improvements by performing a conventional and advanced exergy and exergoeconomic analysis to an industrial-scale spray drying process for the production of instant coffee, using actual operational data. The study analyzed the steam generation unit, the air and coffee extract preheater, the drying section, and the final post treatment process. The performance parameters such as exergetic efficiency, exergoeconomic factor, and avoidable investment cost rate for each individual component were determined. The overall energy and exergy efficiencies of the spray drying system are 67.6% and 30.6%, respectively. The highest rate of exergy destruction is located in the boiler, which amounts to 543 kW. However, the advanced exergoeconomic analysis shows that the highest exergy destruction cost rates are located in the spray dryer and the air heat exchanger (106.9 $/h and 60.5 $/h, respectively), of which 47.7% and 3.8%, respectively, are avoidable. Accordingly, any process improvement should focus on the exergoeconomic optimization of the spray dryer.

Exergoeconomic analysis and optimization of wind power hybrid energy storage system

“…Among them, 0 T -ambient temperature, K ; T -heating temperature of heat storage system, K ; Q -The heat absorbed by the heating process of the heat storage system, J . The heat storage system is heated from A T to B T , The process exergy loss is by Eq (11).…”

“…(1) System exergy efficiency The wind power system is a non-equilibrium dissipative system and there must be irreversible exergy loss in the process of heat-power conversion. In order to improve the exergy efficiency of the system, increasing the output exergy of each subsystem is the input exergy of the next subsystem to reduce the exergy loss of each subsystem [11] . The exergy efficiency of the system in this paper is determined by the exergy efficiency and exergy loss of each subsystem.…”

Assessment of Whole Milk Powder Production by a Cumulative Exergy Consumption Approach

“…Although there are many different studies conducted using this approach in the literature, most of them focused on the drying process and dryers [7]. However, studies on the exergetic evaluation of spray-drying systems are relatively rare [8][9][10][11].…”

Experimental and numerical analysis of thermodynamic performance of microwave dryer of onion

“…However, energy analysis could not deliver beneficial information on worth of different energy forms. Furthermore, energy concept is not alone adequate for sustainable improvement in the systems performance (Tinoco-Caicedo et al, 2020). Therefore, to rectify the inefficiencies of energy analysis and afford a more accurate view, the exergy concept is applied too.…”