Technical feasibility and economic analysis of the bagasse boiler implementation to operate a reheat regenerative rankine cycle in a sugar and alcohol mill

• Grant number: 19/27755-8
• Support type: Research Grants - Innovative Research in Small Business - PIPE
• Duration: February 01, 2021 - January 31, 2023
• Field of knowledge: Engineering - Mechanical Engineering - Thermal Engineering
• Principal researcher: Juan Harold Sosa Arnao
• Grantee: Juan Harold Sosa Arnao
• Company: Juan Harold Sosa Arnao
• CNAE: Fabricação de caldeiras geradoras de vapor, exceto para aquecimento central e para veículos ; Produção e distribuição de vapor, água quente e ar condicionado ; Serviços de engenharia
• City: Ribeirão Preto
• Assoc. researchers: Justo Emilio Alvarez Jácobo
• Associated research grant: 17/00495-0 - Technical feasibility and economic analysis of the bagasse boiler implementation to operate a reheat regenerative rankine cycle in a sugar and alcohol mill, AP.PIPE
• Associated scholarship(s): 21/08911-9 - Characterization of sugarcane bagasse, BP.TT

Abstract

Sugarcane bagasse boilers, whose maximum operating parameters are 400 t/h,10MPa, and 540oCin the Brazilian sugar and alcohol sector, operate in Rankine Cycle and present very shy development as compared to coal boilers, whose parameters can reach at least 2870 t/h, 27.2MPa, and 600oC and which operate in Reheat Regenerative Rankine Cycle. Albeit adverse to bagasse boilers, their present situation represents a great opportunity for improvement: their performance can be enhanced by using coal boiler technology. In this sense, Steam Reheat, which is not yet applied in bagasse boilers, is an interesting alternative in the quest to maximize energy export to the national grid. Phase I of this project showed that bagasse boilers (which are already in place in sugar and ethanol mills) could be retrofitted to operate with Steam Reheat, to export greater energy from the same amount of bagasse as compared to conventional generation systems. Economic analysis of the change to Reheat Regenerative Rankine Cycle demonstrated that this cycle is advantageous over conventional systems. Therefore, Phase II of this project aims to develop a new generation of sugarcane bagasse boilers that operate in Reheat Regenerative Rankine Cycle. A "new" boiler will be designed for a steam mass flow of 200 t/h, and the following systems will be tested: i) Rankine Cycle, ii) Regenerative Rankine Cycle, and iii) Reheat Regenerative Rankine Cycle. The following steam pressure and temperature parameters will be evaluated: a) 6.7MPa and 520oC, b) 10 MPa and 530oC, and c) 12MPa and 540oC. The technical-economic simulations will reveal the best cost/benefit. Cargill - Cevasa sugar mill, located in Patrocínio Paulista, state of São Paulo, is the headquarters of the project and plans on expanding its unit, which involves implementing the new boiler. This project will help to define the characteristics of the power generation system. Characterization of the sugarcane bagasse at the Cevasa sugar mill will include i) proximate analysis (moisture, ash, and fixed and volatile carbon), ii) ultimate analysis (carbon, hydrogen, nitrogen, sulfur, oxygen and chlorine), and iii) higher heating value determination; the lower heating value will be calculated. Due to seasonal variations, the bagasse will be analyzed along all the harvest, and the results will be used in thermal calculations concerning the boiler and the energy generation system. Inka's Boiler plans to develop the boiler steam reheating system with the technical support of the Italian company ESE Engineering Services for Energy SRL. Therefore, the project will be ready to be safely applied in the sugar and alcohol mill. The "new" product will be initially disseminated through the Inka's Boiler company site. There will be technical visits to different clients (in Brazil and abroad) and Workshops will be organized for directors, managers, and decision makers in the sugar and alcohol industry in Brazil and in other South American countries, such as Colombia, Peru, and Ecuador. The first event is scheduled to take place during Fenasucro (the largest world event in the sugar and alcohol industry performed in Sertãozinho, SP). Dissemination of the Project will hopefully attract investment for phase III of the project. (AU)