Study of high-efficiency distillation columns: HIGEE

Author(s)

Ronald Jaimes Prada

• Document type: Master's Dissertation
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Engenharia Química
• Defense date: 2012-04-06

Examining board members

Maria Regina Wolf Maciel; Galo Antonio Carrillo Le Roux; César Benedito Batistella

• Advisor: Maria Regina Wolf Maciel

Abstract

In the last decades, the intensification of processes has attracted the attention of both academia and industry. A Rotating Packed Bed (RPB) was developed in the context of process intensification and it has been widely used in distillation, absorption, desorption, desulfurization, oxidation, crystallization, precipitation, polymerization, and nanomaterials synthesis. In a conventional distillation column, the liquid flows under the influence of the gravity. As a result, large columns are commonly required to achieve high levels of separation. To overcome this limitation, a rotating packed bed distillation column (HIGEE High-gravity contactor) was developed by Ramshaw and Mallinson (1981) for gas-liquid separations, which can induce centrifugal forces over 1000 times that of the earth's gravity. Increasing the driving force of contact between the phases allows greater degrees of volumetric coefficient of mass transfer and high flooding limits (Ramshaw, 1983) allowing a reduction of the size of the equipment in comparison with the size needed to obtain an equivalent mass transfer in a conventional column. A HIGEE column could be operated at a higher gas or liquid flow rate, due to very high flooding capacity. Moreover, it has been showed that this equipment allows the use of packings with a larger specific area (2000-2500 m²/m³) and higher void fraction (0.90- 0.95). In addition, larger driving force of liquid flow and reduced liquid residence time can be obtained in a HIGEE column due to the high rotational speed, which enables to operate equipment with very viscous fluids, heat sensitive materials, and inorganic nanoparticles. The mass transfer efficiency of a rotating packed bed contactor applied to distillation has been studied by few authors using different systems. Therefore, the main objective of this work is to simulate a distillation column of high efficiency (HIGEE Column) in the commercial simulator Aspen Plus V7.2, in order to predict the separation behaviour of the ethanol-water system and to compare this with conventional ones. In order to simulate this equipment in the commercial software, it was introduced a subroutine Fortran to account for the modification on the mass-transfer model of an existing unit. Mass transfer efficiency of RPB under different operating conditions was investigated. The results showed the potential of HIGEE column as an intensified process allowing a considerable reduction in height and volume in comparison with a conventional packed column, showing a promissory alternative for continuous distillation process (AU)

• FAPESP's process: 09/13598-6 - DISTILLATION COLUMN ESTUDY OF HIGH EFFICIENCY:HIGEE
• Grantee: Ronald Jaimes Prada
• Support Opportunities: Scholarships in Brazil - Master