Otimização termohidráulica da operação de redes de trocadores de calor

• Autor(a) principal: Silva, Rachel Luiza da
• Data de Publicação: 2015
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/12056
• topic: Heat Exchange network; fouling; optimization; model; Redes de Trocadores de calor; deposição; otimização; modelo; CNPQ::ENGENHARIAS::ENGENHARIA QUIMICA::OPERACOES INDUSTRIAIS E EQUIPAMENTOS PARA ENGENHARIA QUIMICA

Heat exchanger networks are structures composed of a set of equipment with the objective to allow the heat transfer between process streams, thus reducing the utility consumption. However, these systems are affected by fouling. Fouling is the accumulation of undesired materials on the surface of heat exchangers. The reduction in the thermal effectiveness and the increasing of pressure drop in the equipment are consequences of that phenomenon. According to this scenario, it is proposed the use of a mathematical programming tool for minimizing the cost, over the operation time in networks with heat exchangers in parallel through the flow rate manipulation. The formulation consists of a nonlinear programming problem (NLP) and, due to the non-convergence problems, an automatic procedure was developed to generate initial estimates. The examples were implemented on GAMS 23.7 software, using the solver CONOPT. The computational routine developed contains all mathematical equations of the thermo-hydraulic behavior of shell-and-tube heat exchangers as well as the mechanical energy balance equations of the network, the equations of the fouling thickness model and the fouling rate model, in addition to the objective function, which is represented by the integral of the cost of energy consumption during the operation and the loss of production due to hydraulic limitations. Two versions of the optimization problem formulation were developed, one with integrated equations and other with discretized differential equations, in this case, is possible to analyze the development of fouling along the exchanger. The performance of the computational routine is analyzed using a set of examples, where it is possible to realize the gains in the optimal solution, when compared with other flow control proposals. The main contribution of this paper is the integration of fluid dynamic aspects explicitly in the model