Methods of the present disclosure may comprise: introducing a first effluent and a second effluent in a gasifier of a partial oxidation unit to produce a waste gas, wherein the first effluent comprises one or more hydrocarbon containing feeds and the second effluent comprises air, enriched air with oxygen or oxygen; selectively removing hydrogen sulfide (H.sub.2S) from the waste gas; combining the waste gas and steam in a water-gas shift unit to produce a shift gas comprising hydrogen and carbon dioxide; separating the carbon dioxide from the shift gas in a carbon capture unit to produce a carbon dioxide-enriched effluent and an effluent comprising a hydrogen- and nitrogen-enriched mixture; and recovering the carbon dioxide from the carbon dioxide-enriched effluent.

A process for producing olefins comprising the steps of separating the liquid oil in the fractionator to produce a light oil product; separating the light oil product in the extractor to produce a paraffin fraction stream; increasing a pressure of the paraffin fraction stream in a paraffin pump to produce a pressurized paraffin stream; mixing the pressurized paraffin stream with a pressurized water feed in the water mixer to produce a paraffin-containing water stream; heating the paraffin-containing water stream in the water heater to produce a hot paraffin-water stream, wherein a temperature of the hot paraffin-water stream is greater than 450 deg C., wherein the short chain paraffins are operable to crack at the temperature of the hot paraffin-water stream; mixing the hot paraffin-water stream and the hot feedstock in the feed mixer to produce a mixed feed stream; and introducing the mixed feed stream to the supercritical unit.

A process and system for reducing contaminants contained in a contaminated feedstock comprising mixing the contaminated feedstock with water and at least one of metal scavengers or reactants, to form a feedstock-water-reactant mixture, feeding the mixture under pressure into a hydrothermal purification reactor, wherein the mixture is subject to heat, pressure, and turbulent flow conditions to cause rapid reaction of the inorganic contaminants with the metal scavengers or reactants to form inorganic salts that partition into an aqueous phase and maintaining the temperature, pressure, and turbulent flow conditions of the feedstock-water-reactant mixture for a predetermined space time to prevent the organic portion of the feedstock in the mixture from undergoing a conversion reaction and to form a hydrothermal reactor effluent; and separating the effluent into the aqueous phase containing salts of the inorganic contaminants and an organic phase that contains a lower concentration of inorganic contaminants than the contaminated feedstock.

A process for upgrading a hydrocarbon-based composition that includes combining a supercritical water stream, a hydrogen stream, and a pressurized, heated hydrocarbon-based composition in a mixing device to create a combined feed stream. The process further includes introducing the combined feed stream into a supercritical water hydrogenation reactor operating at a temperature greater than a critical temperature of water and a pressure greater than a critical pressure of water, and at least partially converting the combined feed stream to an upgraded product.

A process for upgrading a hydrocarbon-based composition that includes combining a supercritical water stream, a hydrogen stream, and a pressurized, heated hydrocarbon-based composition in a mixing device to create a combined feed stream. The process further includes introducing the combined feed stream into a supercritical water hydrogenation reactor operating at a temperature greater than a critical temperature of water and a pressure greater than a critical pressure of water, and at least partially converting the combined feed stream to an upgraded product.

A process for upgrading a hydrocarbon-based composition that includes combining a supercritical water stream with a pressurized, heated hydrocarbon-based composition in a mixing device to create a combined feed stream. The combined feed stream is introduced into a supercritical upgrading reactor to at least partially convert the combined feed stream to an upgraded product. The process includes separating the upgraded product to produce a light fraction and a heavy fraction, and separating the light fraction in the gas/oil/water separator to produce a gas fraction, a liquid oil fraction, and a first water fraction; combining the heavy fraction with at least a portion of one of the liquid oil fraction or the first water fraction to form a diluted heavy fraction; and passing the diluted heavy fraction from the flash drum to a demulsifier mixer to form a demulsified heavy fraction.

A process for upgrading a hydrocarbon-based composition that includes combining a supercritical water stream with a pressurized, heated hydrocarbon-based composition in a mixing device to create a combined feed stream. The combined feed stream is introduced into a supercritical upgrading reactor to at least partially convert the combined feed stream to an upgraded product. The process includes separating the upgraded product to produce a light fraction and a heavy fraction, and separating the light fraction in the gas/oil/water separator to produce a gas fraction, a liquid oil fraction, and a first water fraction; combining the heavy fraction with at least a portion of one of the liquid oil fraction or the first water fraction to form a diluted heavy fraction; and passing the diluted heavy fraction from the flash drum to a demulsifier mixer to form a demulsified heavy fraction.

A process for treating a disulfide oil composition that includes combining a supercritical water stream, a hydrogen stream, and a disulfide oil composition in a mixing device to create a combined disulfide feed stream; introducing the combined disulfide feed stream into a supercritical water hydrogenation reactor operating at a temperature greater than a critical temperature of water and a pressure greater than a critical pressure of water; and at least partially converting the combined disulfide feed stream to an upgraded disulfide product.

A process for treating a disulfide oil composition that includes combining a supercritical water stream, a hydrogen stream, and a disulfide oil composition in a mixing device to create a combined disulfide feed stream; introducing the combined disulfide feed stream into a supercritical water hydrogenation reactor operating at a temperature greater than a critical temperature of water and a pressure greater than a critical pressure of water; and at least partially converting the combined disulfide feed stream to an upgraded disulfide product.

A process for producing an upgraded oil blend, the process comprising the steps of introducing the combined stream to a supercritical reactor, wherein a volumetric ratio of water to oil in the combined stream is in the range between 10:1 and 2:1; reacting the combined stream in the supercritical water reactor to produce a reactor effluent, wherein the oil undergoes conversion reactions in the supercritical reactor such that the reactor effluent comprises upgraded bio-oil and upgraded heavy oil; reducing a temperature of the reactor effluent to produce a cooled effluent; operating the soaker to produce a product effluent, wherein a temperature in the soaker is between 250° C. and 350° C., wherein decarboxylation reactions occur in the soaker; and separating the product effluent in the separation unit to produce and the upgraded oil blend, wherein the upgraded oil blend comprises upgraded bio-oil and upgraded heavy oil.