Exergoeconomic analysis in a food industry boiler

Abstract

This study aims to apply the SPECO method in a firetube steam generating unit located in a food industry to measure the cost and to suggest actions that will increase its efficiency. In the current global scenario, researches for alternatives of the cost reduction and increased sustainability are more and more on the agenda in companies. Therefore, the present work develops a study to make possible the energy losses minimization in biomass boilers located in Saudali food industry, Ponte Nova (Minas Gerais, Brazil). The used methodology was developed from the exergoeconomic analysis using the Specific Exergy Costing (SPECO) method. To possibilitate this procedure it was necessary to map all the exergetic flows and to find its thermodynamic values. Regarding the fuel calorific potential, it was necessary the measurement of its average humidity, measured in (25 ± 1%), approximately, in order to obtain a Lower Calorific Power of 15960 kJ.kg-1. The massic and exergy flow rates values were defined using measurement equipments, thermodynamic tables and company’s information. The obtained results for exergetic efficiency, steam cost and fuel cost were, respectively, 51.74%, 0.0446 R$.(kWh)-1 and 0.01490 R$.(kWh)-1. These results evidenced a cost ratio between product and fuel of 1.99, which represents a product cost two times superior to the fuel cost, approximately. It is concluded that SPECO method application in Saudali industry evidenced important and often disregarded points, as the moisture interference in biomass available exergy and great variance between steam and fuel costs.