Avaliação e modelagem da absorção de H2S do gás natural em coluna de leito estagnado
Natural gas, although basically composed by light hydrocarbons, also presents contaminant gases in its composition, such as CO2 (carbon dioxide) and H2S (hydrogen sulfide). The H2S, which commonly occurs in oil and gas exploration and production activities, causes damages in oil and natural gas pipe...
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| Formato: | doctoralThesis |
| Idioma: | por |
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Universidade Federal do Rio Grande do Norte
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| Endereço do item: | https://repositorio.ufrn.br/jspui/handle/123456789/15926 |
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| Resumo: | Natural gas, although basically composed by light hydrocarbons, also presents
contaminant gases in its composition, such as CO2 (carbon dioxide) and H2S (hydrogen
sulfide). The H2S, which commonly occurs in oil and gas exploration and production
activities, causes damages in oil and natural gas pipelines. Consequently, the removal of
hydrogen sulfide gas will result in an important reduction in operating costs. Also, it is
essential to consider the better quality of the oil to be processed in the refinery, thus resulting
in benefits in economic, environmental and social areas. All this facts demonstrate the need
for the development and improvement in hydrogen sulfide scavengers. Currently, the oil
industry uses several processes for hydrogen sulfide removal from natural gas. However,
these processes produce amine derivatives which can cause damage in distillation towers, can
cause clogging of pipelines by formation of insoluble precipitates, and also produce residues
with great environmental impact. Therefore, it is of great importance the obtaining of a stable
system, in inorganic or organic reaction media, able to remove hydrogen sulfide without
formation of by-products that can affect the quality and cost of natural gas processing,
transport, and distribution steps. Seeking the study, evaluation and modeling of mass transfer
and kinetics of hydrogen removal, in this study it was used an absorption column packed with
Raschig rings, where the natural gas, with H2S as contaminant, passed through an aqueous
solution of inorganic compounds as stagnant liquid, being this contaminant gas absorbed by
the liquid phase. This absorption column was coupled with a H2S detection system, with
interface with a computer. The data and the model equations were solved by the least squares
method, modified by Levemberg-Marquardt. In this study, in addition to the water, it were
used the following solutions: sodium hydroxide, potassium permanganate, ferric chloride,
copper sulfate, zinc chloride, potassium chromate, and manganese sulfate, all at low
concentrations (»10 ppm). These solutions were used looking for the evaluation of the
interference between absorption physical and chemical parameters, or even to get a better
mass transfer coefficient, as in mixing reactors and absorption columns operating in counterflow.
In this context, the evaluation of H2S removal arises as a valuable procedure for the
treatment of natural gas and destination of process by-products. The study of the obtained
absorption curves makes possible to determine the mass transfer predominant stage in the
involved processes, the mass transfer volumetric coefficients, and the equilibrium
concentrations. It was also performed a kinetic study. The obtained results showed that the
H2S removal kinetics is greater for NaOH. Considering that the study was performed at low
concentrations of chemical reagents, it was possible to check the effect of secondary reactions
in the other chemicals, especially in the case of KMnO4, which shows that your by-product,
MnO2, acts in H2S absorption process. In addition, CuSO4 and FeCl3 also demonstrated to
have good efficiency in H2S removal |
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