Fadairo, A. S. A. and Ameloko, A. and Ako , C. T. and Duyilemi, O.
MODELING OF WAX DEPOSITION DURING OIL PRODUCTION
USING A TWO-PHASE FLASH CALCULATION.
Petroleum & Coal, 52 (3).
Wax deposition is a serious problem in the Petroleum Industry that results in the plugging of flow strings, formation damage, loss of hydrocarbons, increased production cost. The existing models used jn the oil industry for predicting wax phase equilibrium parameters over-estimate the amount of wax that is formed in terms of the wax weight fraction and the number of moles of solid. The Coutinho correlation is the latest of these models and is used to calculate the melting temperature and the enthalpy of fusion of the crude oil components. It did not consider the effect of branching of carbon atoms in the hydrocarbon structure/compound. But branching of carbon atoms in the hydrocarbon compounds affects its melting point. In this work, the correlation for calculating the melting temperature in crude oil developed by Coutinho has been modified to take into account the effect of branching of carbon-carbon chains in isoparaffins and the model has been used to calculate a new set of equilibrium parameter. The modified regular solution theory was used to calculate the activity coefficient ratio that was used as an input to the new model. Wax phase equilibrium flash calculations were carried out with the new set of equilibrium parameters. The wax mixture was then characterized using the weight fraction of component in the solid phase and weight fraction of component in the solid phase in the mixture. In order to check the reliability of the model, the data presented by Hanquan was used as input into the models developed by Won, Chung, Countinho and the new one. The new model predicted a more conservative value for the number of moles of solid formed, weight fraction of component in the solid phase and weight fraction of component in the solid phase in the mixture for C1s-C4o.This is an improvement over the existing models which overestimate the values of the parameters.
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