Synthesis and genetic algorithm-based optimization to reduce dry weight and footprint of topsides oil & gas processing.

• Ano de defesa: 2021
• Autor(a) principal: Pereira, Leandro Augusto Grandin
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: Algoritmos genéticos; Genetic algorithm; Process optimization; Process synthesis; Processo (Síntese; Otimização); Projeto do Topsides; Topsides design
• Link de acesso: https://www.teses.usp.br/teses/disponiveis/3/3150/tde-20122021-155556/

Oil and gas will remain relevant in the incoming decades, with several new offshore platforms being necessary to satisfy demand, maintaining a high level of greenfield projects activity. The platform design can be accelerated and improved if the typical knowledge-based design is substituted by a framework comprising process synthesis and optimization. A general-purpose mathematical programming process synthesis and optimization tool, with an immediate application in topsides oil & gas processing systems, has been developed in Matlab, comprising elements such as thermophysical properties estimation, process and preliminary mechanical design of several equipment, development of a superstructure and extraction of flowsheets for two types of fluids (oil with low and high CO2 content), parametric analysis, and genetic algorithm-based optimization seeking maximization of oil production and minimization of equipment dry weight and footprint. For each of the assessed fluids in the given inlet conditions, maximum oil production is approximately equal regardless the flowsheet, with an asymptotic behavior between oil production and equipment dry weight or footprint, demonstrating the possibility of achieving oil production very close to the maximum found in the respective Pareto Fronts while significantly reducing equipment dry weight and footprint. Considering the best attributes of assessed flowsheets for oil with low CO2 content, the flowsheet combining pre-compression with TEG dehydration presented equipment dry weight 25.6% and 57.7% lower and equipment footprint 13.6% and 10.6% lower than the other two assessed flowsheets, which relied on TEG (without pre-compression) and molecular sieve (with pre-compression). Considering the best attributes of flowsheets for oil with high CO2 content, the flowsheet combining acetate cellulose membranes (bulk CO2 separation) with MEA (CO2 polishing) showed the best compromise between equipment footprint, equipment dry weight and energy consumption, with equipment dry weight 22% and equipment footprint 26% lower than a flowsheet solely relying on acetate cellulose membranes. A flowsheet solely relying on MEA chemical absorption for CO2 removal presented the best equipment footprint and dry weight, but heating demand is extremely high compared to flowsheets that adopt membranes. The developed process synthesis and optimization tool is efficient, powerful and can be expanded to cover different inlet conditions, production systems and attributes, achieving objectives such as footprint reduction, dry weight reduction, decarbonization, and cost reduction.