Energy-exergy approach of a cogeneration system in pulp and paper industry with a chemical recovery of black liquor and soda

Abstract

The pulp and paper industry is a power-intensive technology so great attention to reducing its own energy consumption and declining the waste of available energy should be devoted. In the current investigation, the energy-exergy approach of a pulp and paper company integrated with a chemical recovery of black liquor (BL) and soda is studied actually for one year. The chemical BL recovery system that has the primary benefits to avoid environmental pollution by burning organic waste and recycling the soda is also comprehensively investigated. Natural gas (NG) and BL are utilized in power boiler (PB) and recovery boiler (RB), respectively. Moreover, in the present implementation, the chemical reactions of NG and BL are presented. The obtained results show that the percentages of energy losses in the condenser, RB, evaporators, and PB are 49.16, 19.28, 14.22, and 3.96%, respectively. The average values of exergy destruction percentages in RB and PB around the year are 41.63 and 33.5%, respectively. The maximum system overall exergy efficiency is 32.09% at an environment temperature of 290 K, whereas the energy efficiency of the system is 53.7%.

Keywords

• Pulp and paper industry
• Cogeneration system
• Energy and exergy analyses
• Recovery system
• Biofuel
• Soda