HYBRID REACTOR HEAVY PRODUCT UPGRADING METHOD WITH DISPERSED CATALYST UPTAKE

Abstract

The invention concerns a process for the hydrotreatment of a heavy oil feed in at least one reactor containing a fixed bed catalyst, in which a solution containing a dispersed catalyst or a precursor of a dispersed catalyst is continuously introduced into said reactor, the particle size of said dispersed catalyst being in the range 1 nm to 100 ?m.

More particularly, the invention concerns the in situ formation of a catalyst for a hydrotreatment process starting from a fixed bed catalyst which captures a dispersed catalyst on its solid support.

Claims

1. A process for the hydrotreatment of a heavy oil feed in at least one reactor containing a fixed bed catalyst composed of an active phase deposited on a solid support, in which a solution containing a dispersed catalyst or a precursor of a dispersed catalyst is continuously introduced into said reactor, the particle size of said dispersed catalyst being in the range 1 nm to 100 ?m, said fixed bed catalyst capturing said dispersed catalyst on its solid support.

2. The process as claimed in claim 1, in which the particle size of said dispersed catalyst is in the range 10 nm to 75 ?m.

3. The process as claimed in claim 1, in which the feed is selected from feeds constituted by hydrocarbon fractions obtained from a crude oil or from atmospheric distillation of a crude oil or from vacuum distillation of a crude oil, said feeds containing a fraction of at least 80% by weight of molecules having a boiling point of at least 300? C.

4. The process as claimed in claim 1, in which the hydrotreatment process is carried out at an absolute pressure in the range 2 MPa to 38 MPa and at a temperature in the range 300? C. to 550? C., and with an hourly space velocity (HSV) of the volume of feed with respect to the volume of catalyst in the range 0.05 h.sup.?1 to 10 h.sup.?1.

5. The process as claimed in claim 1, in which said fixed bed catalyst contains one or more elements from groups 4 to 12 of the periodic table of the elements which are deposited on said solid support.

6. The process as claimed in claim 5, in which said solid support for the fixed bed catalyst is selected from amorphous solids selected from silica, alumina, silica-alumina, titanium dioxide and zeolites, alone or as a mixture.

7. The process as claimed in claim 5, in which the macropore volume of said solid support of the fixed bed catalyst represents in the range 0 to 80% of the total pore volume, the median diameter of the macropores of said solid support of the fixed bed catalyst is in the range 100 nm to 5000 nm, and the specific surface area of said solid support of the fixed bed catalyst is more than 75 m.sup.2/g.

8. The process as claimed in claim 5, in which said fixed bed catalyst contains at least one metal from group VIB.

9. The process as claimed in claim 8, in which said metal from group VIB is selected from molybdenum and tungsten.

10. The process as claimed in claim 8, in which said metal from group VIB is used in association with at least one metal from group VIII.

11. The process as claimed in claim 10, in which said metal from group VIII is selected from nickel and cobalt.

12. The process as claimed in claim 1, in which said solution containing said dispersed catalyst or said precursor of a dispersed catalyst is introduced continuously with the feed or with a conveying fluid.

13. The process as claimed in claim 12, in which said conveying fluid is selected from aromatic hydrocarbons and vacuum distillates, alone or as a mixture.

14. The process as claimed in claim 1, in which said dispersed catalyst or said precursor of a dispersed catalyst is selected from pyrite and molybdenum sulphide or selected from molybdenum naphthenate, nickel naphthenate, vanadium naphthenate, phosphomolybdic acids, ammonium molybdates, molybdenum octoates, nickel octoate, vanadium octoate and pentacarbonyl iron.

15. The process as claimed in claim 1, in which the quantity of dispersed catalyst in the reactor or reactors is in the range 1 ppm by weight to 10000 ppm by weight with respect to the feed.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0064] FIG. 1 is a graph representing the temperature rise profiles necessary in order to compensate for deactivation of the catalyst in accordance with the prior art and in accordance with the invention.

EXAMPLES

Example No 1

Example 1: Fixed Bed Hydrotreatment (not in Accordance with the Invention)

[0065] Example 1 was not in accordance with the invention, in that neither was the catalyst dispersed, nor was the dispersed catalyst precursor injected.

[0066] An atmospheric distillation residue with a D 15/4 density of 0.99 containing 4% by weight of sulphur, and 90 ppm by weight of metals was hydrotreated in the presence of hydrogen under a pressure of 15 MPa with a HSV of 0.8 h.sup.?1. The temperature of the reactor was increased with time in order to compensate for the reduction in activity of the catalyst.

[0067] The active phase of the catalyst employed comprised 4% of molybdenum. Said active phase was deposited onto an alumina type support with a pore volume of 1 mL/g. The macropore volume was 40% of the total pore volume, with a median macropore diameter of 1000 nm.

[0068] The effluent produced by the hydrotreatment had a D 15/4 density of 0.95 and a metals content of 30 ppm by weight.

[0069] The solid line in FIG. 1 shows the profile of the temperature rise for the reaction medium in order to compensate for its deactivation. The initial temperature employed was Tbase. After having increased the temperature by 70? C. with respect to Tbase, the temperature was too high for the hydrotreatment to be able to produce quality products. Tbase+70? C. was reached after 5800 h of reaction.

Example 2: Fixed Bed Hydrotreatment with Continuous Introduction of a Dispersed Catalyst (in Accordance with the Invention)

[0070] The process carried out in Example 2 was similar to the process carried out in Example 1, but with the additional continuous injection of a solution of molybdenum in gas oil concomitantly with the atmospheric distillation residue.

[0071] The molybdenum precursor, molybdenum 2-ethylhexanoate, was mixed with vacuum distillate in order to obtain a quantity of dispersed catalyst in the reactor of 10 ppm by weight with respect to the feed.

[0072] The effluent produced by the hydrotreatment had a D 15/4 density of 0.95 and a metals content of 30 ppm by weight.

[0073] The dashed line in FIG. 1 shows the profile of the temperature rise for the reaction medium in order to compensate for its deactivation. The temperature Tbase+70? C., beyond which the hydrotreatment could no longer be carried out in order to obtain quality products, was reached after 7900 h of reaction.

[0074] FIG. 1 shows that the temperature rise was slower in the process in accordance with the invention. Thus, the process in accordance with the invention can be used to significantly increase the cycle time by 2100 h, i.e. approximately 36%.