Projeto e montagem de uma unidade piloto para operação de um sistema de membranas líquidas surfatantes utilizando-se uma coluna mecanicamente agitada

• Ano de defesa: 2013
• Autor(a) principal: Cibele Konzen
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Engenharia química; Membranas (Tecnologia); Ácido cítrico; Engenharia quimica
• Link de acesso: http://hdl.handle.net/1843/BUOS-9KYHQG

The present work had as main aim the design and the assembly of a pilot plant unity in order to operate a liquid surfactant membrane system (LSM), studying the hydrodynamic and mass transfer of this system, in a mechanically agitated extraction column similar to a Kühni one. The LSM comprise water-oil-water multiple emulsions to separate and/or concentrate several organic or metallic species. This study was developed into two main steps: adaptation and design of equipment and devices required to operation of the liquid surfactant membrane process in continuous pilot plant scale; study of the hydrodynamic and mass transfer conditions inside the column for the liquid surfactant membrane system. The first step involved: design and manufacture of the column internals in order to reproduce a Kühni column geometry and, as much as possible, the flow pattern of an industrial unit; acquisition of an homogenizer for the pilot plant unit and assessment of its efficiency; assembly of a system for image acquisition to register the globule sizes during column operation, and development of a continuous electrostatic demulsifier to split the emulsions used in the liquid surfactant membrane process, including the design, manufacture and evaluation of the performance of the equipment. The second step involved: assembly of the pilot plant unit and pre-operation; b) operation of the pilot plant unit, including the determination of some hydrodynamic parameters for the citric acid/liquid surfactant membrane system and evaluation of the mass transfer conditions for this system by measuring the solute concentration profile along the column. To carry out the experimental work, two phases were used: a continuous phase, composed of synthetic solutions of citric acid at 10% w/v, and a dispersed phase formed by primary emulsions composed of organic phases containing 20% w/w of Alamine 336, 2% w/w of Infineum 9268 and 78% w/w of ExxsolTM D 240/280 and aqueous inner phases containing sodium acetate and Li+ solutions at 4.0 mol.L-1 and 0,1 mol.L-1, respectively. It was possible to recover approximately 60% of the citric acid present into the continuous phase using a phase ratio dispersed/continuous equals to 1/1 (Fd/Fc), and total throughput Ft = 2 L.h-1, column impeller speed equal to 145 rpm and organic phase/stripping phase ratio equal to 3/1. In this operating condition, it was also possible to measure the total hold-up ( = 5.1%) and to determine the Sauter mean diameter of the globules (~ 1,0 mm), their mean slip velocity (4.3 x 10-3 m.s-1), the specific interfacial area (136 m2.m-3) and global mass transfer coefficient of the continuous phase (1.3 x 10-6 m.s-1).