Integração energética da rede de trocadores de calor em uma planta química de produção de ácido sulfúrico

Abstract

With the objective of reducing the operational costs and the consumption of fuels from non-renewable sources, this work applied the Pinch methodology in order to energetically integrate a sulfuric acid production plant from metallurgical gas. With the application of the method, it was verified that this process was able to supply all the needs of the hot utilities, requiring only cold utilities external to the process, which is equivalent to a special class of energy integration problems called Threshold Problems. By studying the influence of ΔTmin, the ΔTthreshold in this process was determined to be 193 °C and that the best ΔTmin for implantation of the network of heat exchangers was 10 °C. We studied two distinct cases in the process, one involving all the currents of the process in the energy integration (case 1) and the other involving only the currents gas of the plant (case 2). With the construction of the heat exchanger networks it was found that it was not of interest for the safety of the process to add heat exchangers which allowed the exchange of heat between gas streams and sulfuric acid streams. The network of heat exchangers for deployment was chosen based on some pre-established standard, such as plant safety and energy savings. For the new layout of the plant, two heat exchangers were added and two heat exchangers were removed. Energy integration resulted in a reduction of R$70,847,851.32 in the plant's annual cost of utilities, representing a saving of 97.0%.