Methods for reducing coke formation in heavy oil upgrading using supercritical water

A process for reducing coke or coke precursor formation in supercritical water comprising:

• producing a supercritical water stream by heating and pressurizing a feed water;
• mixing the supercritical water stream with pressurized, heated feed oil in a mixing device to create a combined feed stream;
• feeding the combined feed stream into a supercritical water (ScW) reactor to produce an upgraded product, where the supercritical water reactor operates at a temperature greater than a critical temperature of water and a pressure greater than a critical pressure of water;
• producing a cooled, depressurized upgraded product by cooling and depressurizing the upgraded product;
• separating the cooled, depressurized upgraded product in a fractionator into a liquid hydrocarbon stream and a hydrocarbon vapor stream;
• condensing the hydrocarbon vapor stream with a cooling device to produce a light hydrocarbon water mixture and a separate gas product;
• and
• recycling the light hydrocarbon water mixture to mix with the feed water upstream of the supercritical water reactor.