Process for isolating mesophase pitch
AssigneeConoco Inc.
InventorsH. Ernest Romine, W. Mark Southard, Edward J. Nanni, Mark W. Carel
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Abstract
The present invention provides a process for obtaining a very clean mesophase pitch from isotropic pitch. This invention utilizes a solvent fractionation process which does not involve the process steps, yield loss and waste generation associated with fluxing and filtering the isotropic pitch. Additionally, this invention provides a liquid/liquid extraction process that avoids the solids handling and the high temperatures and pressures of supercritical fluid extraction. Finally, this invention controls the hardness of the mesophase product.
Claims27
A solvent fractionation process for generating a mesophase pitch from a feed pitch comprising:
- heat soaking a feedstock having less than 500 ppm mesophase insoluble impurities to produce an isotropic heat soaked pitch containing mesogens;
- extracting said heat soaked pitch with a solvent at a temperature and pressure sufficient to maintain said solvent and said mesogens in the liquid state, said temperature and pressure being less than the supercritical temperature and pressure of said solvent to isolate said mesogens;
- recovering said mesogens;
- stripping solvent from said mesogens to yield a mesophase pitch.
A solvent fractionation process for generating a mesophase pitch from a feedstock comprising:
- heat soaking a feedstock having less than 50 ppm ash to produce an isotropic heat soaked pitch containing mesogens;
- extracting said heat soaked pitch with a solvent to isolate said mesogens including substantially all heavy flux insolubles originally present within said feedstock or which were generated during said heat soaking step;
- recovering said mesogens;
- stripping solvent from said mesogens to yield a mesophase pitch.
A solvent fractionation process for generating a mesophase pitch from a feedstock comprising:
- heat soaking a feedstock to produce an isotropic heat soaked pitch containing mesogens;
- controlling the hardness of said mesogens by adjusting the pitch oil content of said heat soaked pitch;
- extracting said heat soaked pitch with a solvent to isolate said mesogens;
- recovering said mesogens;
- stripping solvent from said mesogens to yield a mesophase pitch.
Dependencies are inferred from the claim text.