Effect of Pressure on Wax Precipitation

Effect of pressure on wax precipitation. Pressure increase causes the cloudpoint temperature (which is the temperature at which wax first begins to precipitate) to increase for a liquid mixture of fixed composition. 

TABLE 5.3 Composition and Molecular Weight of the Model-Synthetic Oil (from Pan ef a/., 1997b) 

The solubility of the first precipitating component in the liquid, which is expected to be a heavy normal paraffin at the cloudpoint temperature (CPT), can be expressed as (see Example 5.1) 

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Figure 5.7 shows the effect of pressure on the cloudpoint temperature for three different stock tank oils. Note that these results are based on calculations from the multi solid model. For all three oils, the CPT increases as pressure increases. However, oil 2 is more sensitive to pressure than the other two oils. As we will see in Problems 5.7 and 5.8, the effect of pressure on wax precipitation in gases is different than in liquids. 

Astudenthassimplified the understanding of the effec t of pressure on wax precipitating from natural gases and crude oils through a P vs. P plot shown in Fig. 5.25. Can you extend the plot for the effect of pressure on wax precipitation from a mixture of equilibrium gas and liquid phases ... 

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