Multi-stage supercritical water upgrading of asphaltenes for the production of high-quality mesophase pitch

A method for mesophase pitch production from an asphaltene feedstock, the method comprising:

• introducing the asphaltene feedstock to an asphaltene treatment line;
• introducing the asphaltene feedstock to a first SCW treatment unit of a demetallizing unit;
• demetallizing the asphaltene feedstock, thereby producing a first mixture and a first reaction gas stream, wherein the first mixture comprises a first aqueous fraction and a first pitch;
• separating the first aqueous fraction from the first pitch;
• introducing the first pitch to a second SCW treatment unit of a desulfurizing unit;
• desulfurizing the first pitch, thereby forming a second mixture and a second reaction gas stream, wherein the second mixture comprises a second aqueous fraction and a second pitch;
• separating the second aqueous fraction from the second pitch;
• introducing the second pitch to a third SCW treatment unit of a polycondensation stage;
• performing a polycondensation reaction in the third SCW treatment unit, thereby forming a third reaction gas stream and a third mixture, wherein the third mixture comprises a third aqueous fraction and the mesophase pitch;
• and
• separating the third aqueous fraction from the mesophase pitch, thereby producing the mesophase pitch.

A method for manufacturing carbon fibers from asphaltene feedstock, the method comprising:

• introducing the asphaltene feedstock to an asphaltene treatment line;
• introducing the asphaltene feedstock to a first SCW treatment unit of a demetallizing unit;
• demetallizing the asphaltene feedstock, thereby producing a first mixture and a first reaction gas stream, wherein the first mixture comprises a first aqueous fraction and a first pitch;
• separating the first aqueous fraction from the first pitch;
• introducing the first pitch to a second SCW treatment unit of a desulfurizing unit;
• desulfurizing the first pitch, thereby forming a second mixture and a second reaction gas stream, wherein the second treatment mixture comprises a second aqueous fraction and a second pitch;
• separating the second aqueous fraction from the second pitch;
• introducing the second pitch to a third SCW treatment unit of a polycondensation stage;
• performing a polycondensation reaction in the third SCW treatment unit, thereby forming a third reaction gas stream and a third mixture, wherein the third mixture comprises a third aqueous fraction and a mesophase pitch;
• separating the third aqueous fraction from the mesophase pitch;
• producing the mesophase pitch;
• and
• introducing the mesophase pitch fraction to a series of carbon fiber production units, thereby producing carbon fibers.