| Summary: | Made available in DSpace on 2014-12-17T15:01:44Z (GMT). No. of bitstreams: 1
GeraldineASN.pdf: 1064448 bytes, checksum: e84e59e89db44381c1e32c94012cfe01 (MD5)
Previous issue date: 2007-10-11 === During natural gas processing, water removal is considered as a fundamental step in that combination of hydrocarbons and water favors the formation of hydrates. The gas produced
in the Potiguar Basin (Brazil) presents high water content (approximately 15000 ppm) and its dehydration is achieved via absorption and adsorption operations. This process is carried out at the Gas Treatment Unit (GTU) in Guamar? (GMR), in the State of Rio Grande do Norte. However, it is a costly process, which does not provide satisfactory results when water contents as low as 0.5 ppm are required as the exit of the GTU. In view of this, microemulsions research is regarded as an alternative to natural gas dehydration activities. Microemulsions can be used as desiccant fluids because of their unique proprieties, namely solubilization enhancement, reduction in interfacial tensions and large interfacial area between continuous and dispersed phases. These are actually important parameters to ensure
the efficiency of an absorption column. In this work, the formulation of the desiccant fluid was determined via phases diagram construction, employing there nonionic surfactants (RDG 60, UNTL L60 and AMD 60) and a nonpolar fluid provided by Petrobras GMR (Brazil) typically comprising low-molecular weight liquid hydrocarbons ( a solvent commonly know
as aguarr?s ). From the array of phases diagrams built, four representative formulations have been selected for providing better results: 30% RDG 60-70% aguarr?s; 15% RDG 60-15%
AMD 60-70% aguarr?s, 30% UNTL L60-70% aguarr?s, 15% UNTL L60-15% AMD 60-70% aguarr?s. Since commercial natural gas is already processed, and therefore dehydrated, it was necessary to moister some sample prior to all assays. It was then allowed to cool down to 13?C and interacted with wet 8-12 mesh 4A molecular sieve, thus enabling the generation of gas samples with water content (approximately 15000 ppm). The determination of the equilibrium curves was performed based on the dynamic method, which stagnated liquid phase and gas phase at a flow rate of 200 mL min-1. The hydrodynamic study was done with the aim of established the pressure drop and dynamic liquid hold-up. This investigation allowed are to set the working flow rates at 840 mL min-1 for the gas phase and 600 mLmin-1 for the liquid phase. The mass transfer study indicated that the system formed by UNTL L60- turpentine-natural gas the highest value of NUT === No processamento do g?s natural, a remo??o da ?gua representa uma etapa fundamental, pois a combina??o de hidrocarboneto e ?gua propicia a forma??o de hidratos. O
g?s produzido na Bacia Potiguar apresenta altos teores de ?gua (aproximadamente de 15000 ppmv) e para sua desidrata??o s?o utilizados processos de absor??o e adsor??o. Estes processos s?o utilizados na Unidade de Tratamento de G?s (UTG) em Guamar? (GMR), RN.
S?o considerados onerosos e n?o oferecem bons resultados quando se deseja obter um teor m?ximo de 0,5 ppm de ?gua na jusante da UTG. Dentro deste contexto, a pesquisa na ?rea das microemuls?es surge como alternativa para que sua utiliza??o como l?quido dessecante em um processo de absor??o desidrate o g?s natural. As microemuls?es foram escolhidas por possu?rem alta capacidade de solubiliza??o, redu??o da tens?o interfacial e grande ?rea interfacial entre as fases cont?nua e dispersa, par?metros importantes para garantir a efici?ncia de uma coluna de absor??o. Para a formula??o do l?quido dessecante foram constru?dos diagramas de fases com tr?s tensoativos n?o-i?nicos (RDG 60, UNTL L60 e AMD 60), e aguarr?s (Petrobras-GMR). Diante dos diagramas constru?dos foram utilizados quatro formula??es sendo elas: 30% RDG 60-70% aguarr?s; 15%RDG 60-15%AMD 60-70%
aguarr?s; 30% UNTL L60-70% aguarr?s; 15%UNTL L60-15%AMD 60-70% aguarr?s. Como o g?s natural comercializado ? processado, foi necess?rio umidific?-lo, e para isto ele foi
submetido a resfriamento (13?C), utilizando peneira molecular 4A de 8 a 12 mesh ?mida, e assim obter elevada concentra??o de ?gua (aproximadamente 15000 ppm). A determina??o das curvas de equil?brio foi realizada com base no m?todo din?mico, estando a fase l?quida estagnada e fase gasosa com vaz?o de 200mL/min. O estudo hidrodin?mico foi realizado para determinar a queda de press?o e determina??o do hold-up l?quido din?mico, que determinou que as vaz?es de trabalho deveriam ser 840 mL/min para a fase gasosa e 600 mL/min para a fase l?quida. O estudo da transfer?ncia de massa indicou que o sistema formado por UNTL L60-Aguarr?s-G?s Natural apresentou o maior valor de NUT. Com base nos valores calculados para o AUT dos sistemas, foi poss?vel observar que todos precisam da maior altura de coluna. Com rela??o ao coeficiente global de transfer?ncia de massa, todos os sistemas apresentaram valores pr?ximos, com exce??o do sistema UNTL L60-Aguarr?s-G?s Natural que, dentre os sistemas, ? o que necessita de uma altura maior na coluna. Dentre as quatro formula??es, os sistemas com a presen?a de AMD 60 apresentaram os maiores valores de
coeficiente global de transfer?ncia e efici?ncia, o que mais uma vez comprova a maior solubiliza??o da ?gua em presen?a da mistura de tensoativos ===
|
|---|
