The process produces a diesel stream from a biorenewable feedstock by hydrotreating to remove heteroatoms and saturate olefins. The recycle gas is recycled to the hydrotreating reactor without removing hydrogen sulfide, which is needed in the biorenewable feed to keep the hydrotreating catalyst active. A purification unit can be utilized on a purge gas stream to purify the gas and improve hydrogen concentration in the recycle gas when added to the recycle gas.

A process of producing a distillate fuel from lignin includes: preparing a biomass-derived lignin solvent; dissolving the lignin in the biomass-derived solvent; and separating undissolved lignin and mineral matter to produce a syncrude. In certain embodiments, the process further includes subjecting the syncrude to a hydrotreatment/hydrogenation process to produce a distillate fuel. A process to improve direct lignin liquefaction includes: using a non-hydrogenated lipid in a direct lignin liquefaction process to facilitate lignin depolymerization. A process for using a biomass-derived feedstock as a hydrogen donor includes: providing a biomass-derived feedstock; modifying the feedstock to improve its usefulness as a hydrogen donor; and conducting a transfer hydrogenation process using the modified feedstock as a hydrogen donor.

In an embodiment, a method for decreasing reactor fouling in a steam cracking process is provided. The method includes steam cracking a hydrocarbon feed to obtain a quench oil composition comprising a concentration of donatable hydrogen of 0.5 wt. % or more based on a total weight percent of the quench oil composition; exposing a steam cracker effluent flowing from a pyrolysis furnace to the quench oil composition to form a mixture; and fractionating the mixture in a separation apparatus to obtain a steam cracker tar. In another embodiment, a hydrocarbon mixture is provided. The hydrocarbon mixture includes a mid-cut composition.

A process and system is provided including hydroisomerization reaction zone for production of high octane gasoline blending components that provide high selectivity for producing high octane isomers of light paraffins. A light paraffin feed is enriched by incorporation of dissolved hydrogen, thereby permitting a reaction phase that is liquid or substantially liquid to produce high octane gasoline blending components. Accordingly, a substantially two phase isomerization reactor system is provided, with a hydrogen-enriched liquid feedstock phase and a solid phase catalyst.

Hydrocarbon feeds suitable for use as gasoline blending components containing olefins and aromatic compounds are alkylated in the presence of a catalyst by the olefins present in the feedstream to produce middle distillates having higher boiling points suitable for use as aviation and diesel fuel blending components.

A process for hydrodesulfurizing an olefinic naphtha feedstock while retaining a substantial amount of the olefins, which feedstock has a T.sub.95 boiling point below 250° C. and contains at least 50 ppmw of organically bound sulfur and from 5% to 60% olefins, the process including hydrodesulfurizing the feedstock in a sulfur removal stage in the presence of a gas including hydrogen and a hydrodesulfu-rization catalyst, at hydrodesulfurization reaction conditions, to convert at least 60% of the organically bound sulfur to hydrogen sulfide and to produce a desulfurized product stream, with the associated benefit of such a process providing a lower octane loss at all severities above 60% HDS, compared to a process with similar conversion of organic sulfur with a lower gas to oil ratio, as measured by the selectivity slope, while avoiding excessive increase of equipment size by limiting gas to oil ratio.

The process and apparatus enables purification of a recycle hydrogen gas stream from hydroprocessing biorenewable feedstocks. The recycle gas stream is fed to a methanator reactor to hydrogenate carbon monoxide in the gas stream to water and methane. Other acid gases can be removed by scrubbing preferably upstream of the methanator. Removal of carbon monoxide omits the need for a hydrogen purge stream to avoid carbon monoxide accumulation and enables use of the hydrogen for a downstream hydroisomerization reaction.

A process for conversion of a liquid hydrocarbon feedstock in a moving bed hydroprocessing reactor is provided in which (a) hydrogen gas is dissolved in the liquid feedstock and (b) the mixture is flashed to remove and recover any light components, leaving a hydrogen-enriched feedstock. A homogeneous and/or heterogeneous catalyst is added to the feedstock upstream of the moving bed hydroprocessing rector.

The present invention relates to methods for the conversion of CO.sub.2 to chemical energy carriers and products, in particular via a methanation of the gas phase fraction from a Fischer-Tropsch synthesis.

A fuel production system 1 includes a gasification unit 3; an electrolysis unit; 60 that is connected to a renewable power generating unit 5 and a commercial power grid 8 and produces hydrogen using electric power; and a control unit 7 that determines a power index that depending on the carbon dioxide emission intensity of the electric power supplied from the commercial power grid 8. When the remaining amount of hydrogen is smaller than a lower threshold, the control unit 7 causes electric power to be supplied to the electrolysis unit 60 from the renewable power generating unit 5 and the commercial power grid 8 for production of hydrogen, and controls, based on the power index, the amount of hydrogen supplied by a hydrogen supply pump 64 and the amount of commercial power supply from the commercial power grid 8 to the electrolysis unit 60.