Hydroprocessing process
A process for hydroprocessing a hydrocarbon feedstock includes the steps of providing a hydrocarbon feed having an initial characteristic; providing a first hydrogen-containing gas; feeding the hydrocarbon feed and the first hydrogen-containing gas cocurrently to a first hydroprocessing zone so as to provide a first hydrocarbon product; providing a plurality of additional hydroprocessing zones including a final zone and an upstream zone; feeding the first hydrocarbon product cocurrently with a recycled gas to the upstream zone so as to provide an intermediate hydrocarbon product; and feeding the intermediate hydrocarbon product cocurrently with a second hydrogen-containing gas to the final zone so as to provide a final hydrocarbon product having a final characteristic which is improved as compared to the initial characteristic.
1. A system for hydroprocessing a hydrocarbon feed, comprising:
a first hydroprocessing zone containing a hydroprocessing catalyst and having an inlet for cocurrently receiving a hydrocarbon feed and a first hydrogen-containing gas phase, said first hydroprocessing zone producing a first liquid hydrocarbon product and a gas phase containing hydrogen reaction products, hydrogen and volatile hydrocarbon fractions;
a plurality of additional hydroprocessing zones each containing a hydroprocessing catalyst and including a final zone and an upstream zone, said upstream zone having an inlet for cocurrently receiving said first liquid hydrocarbon product from said first hydroprocessing zone and a recycled hydrogen-containing gas phase, and said upstream zone producing an intermediate product;
a liquid gas separator having an inlet for receiving the intermediate product and producing a separated gas phase containing hydrogen reaction products, hydrogen and volatile hydrocarbon product and a liquid intermediate hydrocarbon product, said final zone having an inlet for cocurrently receiving said liquid intermediate hydrocarbon product from said upstream hydroprocessing zone cocurrently with a second hydrogen-containing gas phase; and
a further separator having an inlet for receiving said gas phase and said separated gas phase so as to produce a separated liquid phase containing said volatile hydrocarbon fractions and a gas phase containing said hydrogen reaction products and hydrogen;
a separator for receiving a product from said final hydroprocessing zone and for separating said product into a hydrocarbon phase and said recycled hydrogen-containing gas phase, wherein said final zone, said separator, said upstream zone, and said liquid gas separator are connected for gas flow in series to define a flow path of hydrogen gas only in a single direction from said final zone to said separator, from said separator to said upstream zone, from said upstream zone to said liquid gas separator and from said liquid gas separator to said further separator.
2. The system of claim 1 , wherein said first hydroprocessing zone is a hydrodesulfurization zone containing a hydrodesulfurization catalyst.
3. The system of claim 1 , wherein said additional hydroprocessing zones comprise at least one additional hydrodesulfurization zone containing a hydrodesulfurization catalyst.
4. The system of claim 1 , wherein each of said first hydroprocessing zone and said additional hydroprocessing zones is a hydrodesulfurization zone containing a hydrodesulfurization catalyst.