Modelagem e simulação da cristalização do cloreto de sódio em misturas com água e monoetileno glicol
The production of natural gas, on offshore platforms, should avoid the occurrence of hydrates, which are crystalline solids that can block the gas flow ducts. The use of monoethylene glycol (MEG) has efficacy already known in the operational environment in relation to the prevention of hydrates. T...
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| Format: | Dissertação |
| Jezik: | pt_BR |
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Universidade Federal do Rio Grande do Norte
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| Online dostop: | https://repositorio.ufrn.br/handle/123456789/31368 |
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| Izvleček: | The production of natural gas, on offshore platforms, should avoid the occurrence
of hydrates, which are crystalline solids that can block the gas flow ducts. The use of monoethylene glycol (MEG) has efficacy already known in the operational environment in relation to the
prevention of hydrates. The MEG is injected into the submerged pipeline and acts as a hydrate
inhibitor, as it reduces the freezing point of the fluid produced by the gas reservoir (water + salts
+ hydrocarbons). This fluid arrives at the platform mixed with the injected MEG, but this must be
regenerated/recovered to reuse it. This is possible through an MEG regeneration plant installed
on the platform itself. However, it is at this stage that technical difficulties may occur due to
the presence of MEG. The water produced by the reservoir is saline and, therefore, the presence
of salts can cause incrustations in the MEG regeneration unit, since this substance reduces the
solubility of the present salts. The Sodium chloride (NaCl) is the salt with the highest concentration in this system. If the NaCl concentration is above solubility, unwanted precipitation of
its crystals may occur. This crystallization and eventual precipitation can cause problems such
as incrustations, which are very harmful in some equipment that make up the regeneration plant.
This can be accomplished through the use of a computer simulator that can, from the operational
conditions of the plant and laboratory data, calculate the concentrations of the species in a timely
manner and, if necessary, the amount of salt precipitated during the MEG regeneration process.
This work aimed to create a simulator that can perform mass balance calculations to determine
the salt concentration and, based on the knowledge of solubility, quantify the occurrence of salt
precipitates, only providing the variables temperature, salt concentration in the food, mass fraction of MEG on a salt-free basis and mass flow. The simulator has a graphical interface that
allows the user to provide the necessary operational data and, based on that, calculate the salt
concentrations in the ternary mixture. The simulator was created using the Python programming
language. Due to the existence of a kinetics for the deposition of salt, other solids and impurities,
the simulator calculates only the amount of crystallized salt present in the process currents, since
precipitation depends on other fluid dynamic factors that are not part of the scope of this study. |
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