Avaliação da recompressão mecânica de vapor em colunas de destilação: estudo de caso em uma indústria de elastômeros sintéticos

Abstract

This work addresses an opportunity and feasibility study to implement mechanical vapor recompression (MVR) in a distillation column of a petrochemical plant for the manufacture of synthetic elastomers. Due to the strong energy consumption of distillation columns, the study aims to recover waste heat from the column to increase its energy and environmental performance. In this proposed system, the vapor that exits at the top of the column is sent to a compressor to increase its energy, so that it can be reused to vaporize the mixture in the column's reboiling flask. To develop the study, two computer simulations of the system were performed using the Aspen Plus software. The first consists in using real data from the process operation. The second consists in the coupling of mechanical vapor recompression in order to verify, by comparison, if this second process is adequate to increase energy efficiency. Furthermore, an economic evaluation was performed to verify if the technology is viable from the economic point of view. Through simulation, it was found that the compressor flow has sufficient heat exchange capacity to provide 83% of the heat required for the column. Beyond that, the addition of an energy integration step allows 88% of the process energy to be recovered. In this scenario, the economic evaluation shows a reduction in operating expenses of 1.7 million dollars per year for a one-time investment estimated at 3.1 million dollars. The payback period of the initial investment is expected to be two years. From an environmental point of view, the study shows a gain with regard to an advantageous reduction of carbon dioxide emissions by 3.787 tons of CO2 per year.