Slurry hydroconversion process for upgrading heavy hydrocarbons
Systems and methods are provided for partial upgrading of heavy hydrocarbon feeds to meet transport specifications, such as pipeline transport specifications. The systems and methods can allow for one or more types of improvement in heavy hydrocarbon processing prior to transport. In some aspects, the systems and methods can produce a partially upgraded heavy hydrocarbon product that satisfies one or more transport specifications while incorporating an increased amount of vacuum gas oil and a reduced amount of pitch into the partially upgraded heavy hydrocarbon product. In other aspects, the systems and methods can allow for increased incorporation of hydrocarbons into the fraction upgraded for transport, thereby reducing or minimizing the amount of hydrocarbons requiring an alternative method of disposal or transport. In still other aspects, the systems and methods can allow for reduced incorporation of external streams into the final product for transport while still satisfying one or more target properties.
1. A method for upgrading a heavy hydrocarbon feed, comprising:
splitting an initial feedstock to form a heavy hydrocarbon feed and a second feedstock portion, the heavy hydrocarbon feed comprising 15 wt % to 95 wt % of the initial feedstock,
wherein the initial feedstock comprises a first diluent;
separating the heavy hydrocarbon feed to form a first fraction comprising 50 wt % or more of a 566° C.+ portion, a bypass fraction comprising 566° C.+ portion, a diluent fraction comprising the first diluent, and one or more additional fractions comprising a 177° C.+ portion, the heavy hydrocarbon feed comprising an API gravity of 15° or less;
exposing at least a portion of the first fraction and a pitch recycle stream to slurry hydroconversion conditions at a combined feed ratio of 1.5 or more to form a hydroconverted effluent, the hydroconversion conditions comprising a total conversion of 60 wt % to 89 wt % relative to 524° C.;
separating at least the pitch recycle stream and a second hydroconverted fraction comprising a 177° C.+ portion from the hydroconverted effluent, the pitch recycle stream comprising more than 50 wt % of 566° C.+ components; and
blending at least the second feedstock portion, the bypass fraction, the one or more additional fractions, and at least a portion of the second hydroconverted fraction to form a heavy hydrocarbon product having a kinematic viscosity at 7.5° C. of 500 cSt or less and an API gravity of 18° or more,
wherein optionally the heavy hydrocarbon product comprises 5 wt % to 15 wt % of the bypass fraction relative to a weight of the heavy hydrocarbon product, and
wherein optionally a vacuum gas oil fraction of the heavy hydrocarbon product comprises 0.1 wt % to 2.0 wt % of n-pentane insolubles relative to a weight of the vacuum gas oil fraction.
2. The method of claim 1 , wherein the heavy hydrocarbon product comprises 20 wt % or less of a 177° C.− fraction relative to a weight of the heavy hydrocarbon product.
3. The method of claim 1 , wherein the second hydroconverted fraction comprises an olefin-containing fraction, the method further comprising hydrotreating at least a portion of the olefin-containing fraction to form a stabilized product, and wherein blending at least the second feedstock portion, the bypass fraction, one or more additional fractions, and at least a portion of the second fraction comprises blending at least the second feedstock portion, the bypass fraction, one or more additional fractions, and at least a portion of the stabilized product to form the heavy hydrocarbon product.
4. The method of claim 1 , wherein the pitch recycle stream comprises 60 wt % or more of 566° C.+ components, or wherein the pitch recycle stream comprises 50 wt % or more of 593° C.+ components, or a combination thereof.
5. The method of claim 1 , wherein the first fraction comprises 60 wt % or more of 566° C.+ components, or wherein the first fraction comprises 50 wt % or more of 593° C.+ components, or a combination thereof.
6. The method of claim 1 , wherein the combined feed ratio is 1.6 to 3.0, or wherein a weight of the first fraction is 50 wt % or less of a weight of the heavy hydrocarbon feed, or a combination thereof.
7. The method of claim 1 , wherein the per-pass conversion at 524° C. is 50 wt % or less, or wherein the per-pass conversion at 524° C. is lower than the total conversion at 524° C. by 25 wt % or more, or a combination thereof.
8. The method of claim 1 , wherein the one or more additional fractions comprise 5.0 wt % or less of 177° C.− components, or wherein the heavy hydrocarbon product comprises 10 wt % or less of the 177° C.− fraction, or a combination thereof.
9. The method of claim 1 , wherein the heavy hydrocarbon product comprises 50 wt % or more of a 343° C.-566° C. fraction relative to a weight of the heavy hydrocarbon product; or wherein the first fraction comprises a first nitrogen content, and wherein the hydroconverted effluent comprises an effluent 177° C.+ portion, the effluent 177° C.+ portion comprising a nitrogen content that is at least 75 wt % of the first nitrogen content; or a combination thereof.
10. The method of claim 1 , wherein separating the heavy hydrocarbon feed comprises performing solvent deasphalting on at least a portion of the heavy hydrocarbon feed, and wherein the first fraction comprises deasphalter rock.
11. The method of claim 1 , wherein the slurry hydroconversion conditions comprise a temperature of 400° C. to 480° C., a pressure of 1000 psig to 3400 psig, and a LHSV of 0.05 hr −1 to 5 hr −1 .
12. The method of claim 1 , wherein the blending comprises blending at least the diluent comprising a 177° C.− portion, the second feedstock portion, the bypass fraction, the one or more additional fractions, and the at least a portion of the second hydroconverted fraction to form the heavy hydrocarbon product.