Chevron U.s.a. Inc.

Roger D Van Gelder

Richard O Moore, Jr

Grant C Hilton

Clive Jones

Randall B Pruet

An integrated process for producing desulfurized hydroprocessed products from Fischer-Tropsch synthesis is disclosed. The process involves isolating and desulfurizing a methane-rich stream from a natural gas source in a first separation zone and a desulfurization zone. The methane-rich stream is converted to syngas and subjected to a hydrocarbon synthesis step, for example, a Fischer-Tropsch synthesis step. The products from the hydrocarbon synthesis step typically include a C &minus; fraction, a C fraction, and a C &plus; wax fraction. These fractions are isolated in a second separation zone, typically via fractional distillation. The C &minus; fraction can be recycled through the first separation zone to provide a second methane-rich fraction for conversion to synthesis gas. The C &minus; fraction can optionally be treated, for example, with hydrotreatment or hydroisomerization catalysts and conditions before or after passage through the first separation zone. The hydrocarbons in the C and C &plus; wax fractions are subjected to additional process steps, for example, hydrotreatment, hydroisomerization, hydrocracking (particularly in the case of the wax fraction), preferably in the presence of sulfur-containing compounds. The products of the additional process steps are sent to a third separation zone, and yield one or more fractions useful, for example, in fuel-related products (preferably C hydrocarbons) as well as an additional C4&minus; fraction. The additional C4&minus; fraction, which can include sulfur impurities resulting from the hydroconversion reaction, can also be desulfurized in the desulfurization zone along with the natural gas. This eliminates the need for a second desulfurization zone. The desulfurization zone can be scaled up from its normal size, if desired, to accommodate the additional sulfur removal resulting from the hydroconversion.

Removing sulfur from hydroprocessed fischer-tropsch products

An integrated process for improved hydrocarbon recovery from a natural gas resource is disclosed. A methane-rich stream, an LPG stream and optionally a C5&plus;  stream are isolated from a natural gas source in a first separation zone and desulfurized. The methane-rich stream is converted to syngas and subjected to hydrocarbon synthesis, for example, Fischer-Tropsch synthesis. The products from the hydrocarbon synthesis typically include a C4&minus; fraction, a C5-C20 fraction, and a C20&plus; wax fraction. These fractions are isolated in a second separation zone. The C4&minus; fraction is recycled through the first separation zone to provide methane for conversion to synthesis gas and an additional LPG fraction. The C4&minus; fraction can be treated, for example, with hydrotreating or hydroisomerization catalysts and conditions before or after the separation. The C5-C20 fraction and the C20&plus; wax and heavy fraction are subjected to additional process steps, for example, hydro treatment, hydroisomerization, and/or hydrocracking. The products are sent to a third separation zone, and yield an additional C4&minus; fraction, as well as higher molecular weight products. The additional C4&minus; fraction can also be sent to the first separation zone and treated in an analogous fashion to the C4&minus; fraction from the hydrocarbon synthesis. Any sulfur-containing compounds resulting from the additional processing of the hydrocarbon synthesis products (i.e., hydroconversion reactions) can be treated along with the sulfur-containing compounds in the natural gas, eliminating the need for a second sulfur-treatment plant.

Hydrocarbon recovery in a fischer-tropsch process

An integrated process for producing a hydrocarbon stream, preferably including predominantly C normal and iso-paraffins, is disclosed. The process involves isolating a C &minus; stream and, optionally a C &plus; stream (&ldquo;natural gas condensate&rdquo;) from a natural gas source. The C &minus; stream is converted to syngas, and the syngas used in a hydrocarbon synthesis process, for example, Fischer-Tropsch synthesis. In one embodiment, one or more fractions from the hydrocarbon synthesis are blended with one or more crude oil derived fractions, and, optionally, the natural gas condensate, such that the overall sulfur content of the blend is less than about 200 ppm. If necessary, the crude oil fractions and/or natural gas condensate can be treated to lower the sulfur content so that the blend has an acceptable sulfur level. The fraction from the hydrocarbon synthesis may include, for example, C hydrocarbons, C &plus; hydrocarbons, or C &plus; hydrocarbons. In this embodiment, the hydroprocessing catalysts are noble metal-containing catalysts, which tend to be sensitive to sulfur concentrations above about 200 ppm. The catalysts preferably have high selectivity for C &plus; products, such that a significant C &minus; fraction is not formed. In another embodiment, one or more fractions from the hydrocarbon synthesis are blended with one or more crude oil derived fractions, and, optionally, the natural gas condensate, such that the overall sulfur content of the blend is more than about 200 ppm. The fraction from the hydrocarbon synthesis may include, for example, C hydrocarbons, C &plus; hydrocarbons, or C &plus; hydrocarbons. In this embodiment, conventional sulfur-tolerant hydroprocessing catalysts can be used.

Co-hydroprocessing of Fischer-Tropsch products and crude oil fractions

An integrated process for producing a hydrocarbon stream including C normal and iso-paraffins is disclosed. A de-sulfurized methane-rich stream and a natural gas condensate are isolated from the natural gas source. The methane-containing stream is converted into syngas, which is then subjected to a hydrocarbon synthesis process, for example, Fischer-Tropsch synthesis. One or more fractions from the hydrocarbon synthesis are blended with the natural gas condensate for co-hydroprocessing, where the blended stream includes less than about 200 ppm sulfur. Olefins and oxygenates are hydrotreated to form paraffins. Paraffins are subjected to hydroisomerization conditions to form isoparaffins. Hydrocarbons with chain lengths above a desired value, for example, C , are hydrocracked. The hydrogenolysis that would otherwise form undesired C fractions is minimized by judicious selection of noble metal catalysts.

Co-hydroprocessing of fischer-tropsch products and natural gas well condensate

An integrated process for producing a hydrocarbon stream including C normal and iso-paraffins is disclosed. The process involves isolating a non-sulfur containing methane stream and a sulfur-containing C &plus; stream from a natural gas source. The methane stream is converted to syngas and further reacted to form a higher molecular weight hydrocarbon product stream. The C hydrocarbons in that product stream are hydroprocessed along with at least a portion of the C &plus; stream from the natural gas source. The presence of sulfur in the C &plus; stream minimizes the hydrogenolysis that would otherwise occur if the C hydrocarbons were hydroprocessed without added sulfur-containing compounds or other hydrocracking suppressants. The result is an improved yield of C hydrocarbons relative to when the hydroprocessing step does not include hydrocracking suppressants.

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Beaconsfield, United Kingdom

Roger D Van Gelder