JP3157323B2 - Hydrotreating method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a process for hydrotreating hydrocarbon oils which are substantially liquid under process conditions in a single reaction vessel containing at least the upper and lower catalyst beds, It relates to a reaction vessel suitable for carrying out the method.

[0002]

BACKGROUND OF THE INVENTION In accordance with environmental regulations, the amount of polluting compounds, such as sulfur and aromatics, that can be present in hydrocarbon oils is expected to continue to decrease in the future. Therefore, there is considerable interest in methods that can reduce the content of these compounds in hydrocarbon oils to industrially attractive low levels. For example, British Patent 1,420,248
In some catalytic desulfurization processes, such as those described in U.S. Pat. No. 6,095,097, two or more fixed bed catalytic systems each comprising one or more reaction vessels are used. The investment required for these methods using several reaction vessels is higher than the investment required for the single reaction vessel method according to the invention.

[0003]

SUMMARY OF THE INVENTION The present invention relates to a process for hydrotreating a hydrocarbon oil that is substantially liquid under process conditions in a single reaction vessel containing at least an upper and lower catalyst bed, comprising: i) contacting the partially hydrotreated hydrocarbon oil obtained in the following step (iv) with the hydrotreating catalyst at an elevated temperature and pressure in the presence of a clean hydrogen-containing gas at the upper catalyst bed; ii) separating the effluent of step (i) into a hydrotreated hydrocarbon oil and a spent hydrogen-containing gas;
Removing the hydrotreated hydrocarbon oil from the process;
(Iii) contacting the fresh hydrocarbon oil at an elevated temperature and pressure in the presence of the used hydrogen-containing gas obtained in step (ii) with the hydrotreating catalyst on the lower catalyst bed; (I
v) separating the effluent of step (iii) into a partially hydrotreated hydrocarbon oil and a contaminated hydrogen-containing gas, removing the contaminated hydrogen-containing gas from the step, and (v) obtaining in step (iv) Transporting the partially hydrotreated hydrocarbon oil to the step (i).

[0004] In the process of the present invention, the final hydrotreating step is performed in the presence of hydrogen, which may also contain relatively small amounts of hydrogen sulfide, which results in good hydrotreating results. The hydrotreating method of the present invention is described, for example, in US Pat.
It differs from the conventional hydrotreating method as described in JP-A-243,519 in the order of the treatment steps. In the process of the present invention, the final hydrotreating step is performed in the upper catalyst bed. In contrast, in a conventional method, the final hydrotreating step is performed in the lower catalyst bed, which is located further downstream of the hydrogen gas stream. Operating the final treatment step on the upper catalyst bed has the advantage that the catalyst bed can be operated at the highest hydrogen partial pressure maintained in the vessel based on the pressure drop on the vessel. Higher hydrogen partial pressures give better hydroprocessing results.

[0005] Further, the use of a feedstock that is substantially liquid under the processing conditions can be used to separate the hydrocarbon oil from the hydrogen-containing gas and to separate the gas from the liquid by cooling the partially hydrotreated oil. Without reheating the partially hydrotreated oil, which is disadvantageous from an economic point of view. Thus, the same good results as in the countercurrent operation scheme can be obtained without suffering the inherent disadvantages of countercurrent operation, such as limitations on the space velocity of gases and liquids. The invention further relates to a reaction vessel suitable for hydrotreating hydrocarbon oils according to the invention, the vessel comprising (a) a gas inlet and a liquid inlet above an upper zone holding a catalyst bed. (B) locating separation means for separating liquid and gas between the upper zone and the lower zone holding the catalyst bed, and (c) separating the liquid between the upper zone holding the catalyst bed and the separation means. Position the exit,
(D) locating a liquid inlet between the separation means and the lower zone holding the catalyst bed, and (e) an outlet for gas and an outlet for liquid or a liquid and gas below the lower zone holding the catalyst bed. For the liquid obtained from the liquid outlet located below the lower zone holding the catalyst bed in the vessel to the liquid inlet located above the upper zone holding the catalyst bed. It is characterized by mounting means for transportation.

The process according to the invention preferably comprises step (iii)
And the subsequent hydrodesulfurization step in step (i). In this way,
Extremely low sulfur levels can be achieved industrially attractively. Other contaminants, such as nitrogen-containing compounds, can also be removed to some extent in the hydrodesulfurization step. Further, the method includes a hydrodesulfurization step in step (iii) followed by a hydrotreating step in step (i).
In this way, both the sulfur content and the aromatics content of the fresh hydrocarbon oil can be industrially attractively reduced. The hydrocarbon oils treated by the process of the present invention are substantially liquid under the treatment conditions. The liquid phase of hydrocarbon oil is
It is possible to easily carry out the separation of the hydrotreated hydrocarbon oil from the hydrogen-containing gas in the step (ii).
Preferably, this separation is carried out using one or more separating trays consisting of conventional liquid draw trays as used in distillation units.

The separation in step (iv) can be performed inside or outside the reaction vessel. In the first case, the hydrocarbon oil generally needs to be cooled and heated before use in step (i). Therefore, separation inside the reactor using the above-mentioned separation tray is preferable.
The pressure drop over the reaction vessel is generally between 0.2 and 10 bar, in particular between 0.5 and 5 bar. Hydrogen can be added to the lower catalyst bed. However, the hydrogen partial pressure is generally higher in the upper catalyst bed than in the lower catalyst bed.
The pressure drop is generally such that the hydrogen partial pressure in the upper catalyst bed is 0.1 to 9 bar, in particular 0.4 to 0.9 bar, in the lower catalyst bed.
4.5 bar higher.

The expression “clean hydrogen-containing gas” is 3
A gas containing less than 0.5% by volume, preferably less than 0.5% by volume, particularly preferably less than 0.1% by volume, of hydrogen sulfide is meant. Preferably, the contaminated hydrogen-containing gas obtained in step (iv) is cleaned, for example by treatment with an amine, and then used in step (i) as a clean hydrogen-containing gas. Hydrocarbon oils that are substantially liquid under the processing conditions are, for example, greater than 70% by weight, preferably greater than 80% by weight, particularly preferably greater than 95% by weight .
It means that the amount of hydrocarbon oil consists of the liquid phase. Suitably, the hydrocarbon oils treatable by the process of the present invention comprise any hydrocarbon which is substantially liquid under the treatment conditions, such as a kerosene fraction. The hydrocarbon oil which can be suitably treated in this way is a gas oil. This is because the environmental restrictions on this oil fraction have become very strict. Suitable gas oils are substantially, for example, 75% by weight.
Most are gas oils that boil in the range of 150-400 ° C. When the gas oil is hydrotreated by the method of the present invention, steps (i) and (iii) are suitably performed at 150-450 ° C, preferably 300-400 ° C, more preferably 325-3 ° C.
Step (i) is suitably carried out at a pressure of from 20 to 85 bar, preferably from 30 to 65 bar, and the step (iii)
At a pressure of 15 to 80 bar, preferably 25 to 60 bar.

Furthermore, in the process according to the invention, preferably, for example, substantially more than 95% by weight is from 320 to 600 ° C.
A lubricating oil such as a lubricating oil boiling in the range can be hydrotreated. When the lubricating oil is hydrotreated by the method of the present invention, steps (i) and (iii) are preferably carried out at 300-4.
It is carried out at a temperature of 00 ° C, preferably 325-390 ° C, more preferably 340-385 ° C and a pressure of less than 250 bar, preferably less than 200 bar, more preferably less than 175 bar. The hydrotreating catalyst used in the method of the present invention is preferably a periodic table of elements (Handbook of Chemistry and Physics, No. 63).
1b, 2a, 4b, 5b, 6b, 7b and 8
It comprises one or more metals selected from the group on a solid carrier. The carrier can be composed of zeolite as needed.

As described above, the hydrotreating method according to the present invention preferably comprises a hydrotreating step in step (i) and a hydrodesulfurization step in step (iii), or both steps include hydrodesulfurization. Process. In the first method, in step (i), the hydrotreating catalyst is applied under hydrotreating conditions including a temperature of 150 to 350 ° C., and in step (iii), the hydrodesulfurization catalyst is hydrogenated. Apply under desulfurization conditions. in this case,
The hydrodesulfurization of step (iii) generally must be carried out to obtain a sulfur content that closely matches the sulfur tolerance of the hydrogenation catalyst of step (i). Otherwise, the hydrogenation catalyst may be poisoned.
Suitably, the hydrocarbon oil obtained in step (iv) contains no more than 15% by volume, preferably no more than 10%, by volume of the sulfur-containing compound present in the fresh hydrocarbon oil.

In the second method, steps (i) and (ii)
In both i), the hydrodesulfurization catalyst is applied under hydrodesulfurization conditions. In this case, the partially hydrotreated hydrocarbon oil obtained in step (iv) preferably contains 1 to 30% by volume of the sulfur-containing compound per volume of the sulfur-containing compound present in the fresh hydrocarbon oil. I do. The present invention can be preferably carried out in the reaction vessel shown in FIG.

The upper catalyst bed can contain a hydrodesulfurization or hydrogenation catalyst, and the lower catalyst bed contains a hydrodesulfurization catalyst. Clean hydrogen-containing gas is supplied to the reactor via path 2 while the partially hydrotreated hydrocarbon oil is introduced via path 1 into the upper part of the reactor. The inlet for the gas and the inlet for the liquid can also be merged. However, it is preferred to provide separate inlets. The hydrotreated effluent from the upper catalyst bed is separated from the gas by a withdrawal tray. The separated hydrotreated hydrocarbon effluent is removed from the reactor via path 3, while the spent hydrogen-containing gas passes through the separation tray to the lower catalyst bed. Fresh hydrocarbon oil is introduced via line 4 between the separation tray and the lower catalyst bed. The partially hydrotreated effluent obtained after the fresh hydrocarbon oil has passed through the lower catalyst bed is removed from the reactor via path 5 and the partially hydrotreated hydrocarbon oil (which is And contaminated hydrogen-containing gas. The contaminated hydrogen-containing gas is preferably cleaned by treatment with an amine and so-called scrubbed. The resulting clean gas can then be recycled to path 2 together with make-up hydrogen, if necessary, and reused.

[0013]

The present invention will be further described with reference to the following examples. This method was performed with the apparatus shown in FIG. The catalyst present in both the upper and lower catalyst beds was a hydrodesulfurization catalyst, which consisted of 3.1% by weight of cobalt and 12.4% by weight of molybdenum, based on the total amount of catalyst on alumina. The catalyst particles were in the form of a 1.2 mm trilobe. According to the ASTM distillation curve, 78% by volume or more is 38%.
A gas oil feed that is gaseous at 3 ° C., 50% by volume or more at 345 ° C. and 20% or more at 300 ° C. is supplied to the reactor via path 4 . All process conditions were at a temperature of 360 ° C. and 2.0 kg / l. h space-time velocity and a hydrogen / oil ratio of 200 Nl / kg. The hydrogen partial pressure at the outlet of the upper catalyst bed was 24.4
In contrast to bar, the hydrogen partial pressure at the outlet of the lower catalyst bed was 23.1 bar. Under these process conditions, about 7% by weight of the gas oil feed was in the gas phase. The sulfur content of the feed, the partially hydrotreated feed, and the hydrotreated feed is shown in Table 1 as the amount of elemental sulfur relative to the total feed.

[0014]

Table 1 Partial hydrogenation Hydrogenation Feeds Treated feeds Treated feeds Sulfur content (% by weight) 1.64 0.21 0.06

If not according to the invention, the fresh feedstock was processed in a similar apparatus as in FIG. 1 under substantially the same processing conditions as described above. No intermittent hydrogen separation was performed between the catalyst beds, and no hydrocarbon oil was added or removed between the catalyst beds. The hydrogen partial pressure at the reactor outlet was 23.1 bar. The resulting hydrotreated hydrocarbon oil had a sulfur content of 0.11% by weight.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a reaction vessel for performing the method of the present invention.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Ouke Huim de Vries, Netherlands 1031 CM Ems Therdam, Bathausweich 3 (56) References JP-B-36-16128 (JP, B1) US Patent 4,435,519 ( (US, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C10G 65/04 EPAT (QUESTEL)

Claims (14)

(57) [Claims] 1. In hydrotreating a hydrocarbon oil that is substantially liquid under process conditions in a single reaction vessel containing at least the upper and lower catalyst beds: (i) the following steps (iv): Contacting the partially hydrotreated hydrocarbon oil obtained in) with the hydrotreating catalyst at an elevated temperature and pressure in the presence of a clean hydrogen-containing gas at the upper catalyst bed; (ii) step (i) Effluent is separated into a hydrotreated hydrocarbon oil and a used hydrogen-containing gas, and the hydrotreated hydrocarbon oil is removed from the process, and (iii) fresh hydrocarbon oil is enriched. At the lower temperature and pressure in the presence of the spent hydrogen-containing gas obtained in step (ii) with the hydrotreating catalyst on the lower catalyst bed; (iv) the effluent of step (iii) Separating the partially hydrotreated hydrocarbon oil and the contaminated hydrogen-containing gas, the contaminated water Was removed containing gas from step, (v) hydrotreating process of a hydrocarbon oil, characterized in that the transporting step (iv) hydrocarbon oil treated partially hydrogenated obtained in the in step (i). 2. The method according to claim 1, wherein the contaminated hydrogen-containing gas obtained in step (iv) is purified and used in step (i). 3. The method according to claim 2, wherein the contaminated hydrogen-containing gas is cleaned by treatment with an amine. 4. The method according to claim 1, wherein the clean hydrogen-containing gas contains less than 3% by volume of hydrogen sulfide. 5. The process according to claim 1, wherein the hydrocarbon oil is a gas oil which substantially boils in the range of 150 to 400 ° C. 6. The method according to claim 6, wherein steps (i) and (iii) are performed in the range of 325 to 39.
6. The process according to claim 5, wherein the step (i) is carried out at a pressure of 20 to 85 bar and the step (iii) is carried out at a pressure of 15 to 80 bar. 7. The method according to claim 1, wherein the hydrocarbon oil is a lubricating oil which substantially boils in the range of 320 to 600 ° C. 8. Steps (i) and (iii) are carried out at 325-39.
The process according to claim 7, which is carried out at a temperature of 0 ° C and a pressure of less than 200 bar. 9. The catalyst according to claim 1, wherein the catalyst is 1b, 2a, 4 of the Periodic Table of the Elements.
4. A solid carrier comprising one or more metals from groups b, 5b, 6b, 7b and 8 on a solid carrier.
The method according to any one of claims 8 to 13. 10. The process according to claim 1, wherein in step (i) the hydrogenation catalyst is applied under hydrogenation conditions and in step (iii) the hydrodesulfurization catalyst is applied under hydrodesulfurization conditions. A method according to claim 1. 11. The hydrocarbon oil obtained in the step (iv),
2. The composition of claim 1, wherein the sulfur-containing compound is present in the fresh hydrocarbon oil in an amount of up to 10% by volume, based on the volume of the sulfur-containing compound.
The method according to 0. 12. The process according to claim 1, wherein in steps (i) and (iii), the hydrodesulfurization catalyst is applied under hydrodesulfurization conditions. 13. The hydrocarbon oil obtained in step (iv),
The sulfur-containing compound is present in an amount of 1 to 30% by volume based on the volume of the sulfur-containing compound present in the fresh hydrocarbon oil.
3. The method according to 2. 14. A reaction vessel suitable for the hydrotreating of hydrocarbon oils according to claim 1, comprising: (a) a gas inlet and a liquid above the upper zone holding the catalyst bed. (B) positioning a separating means for separating liquid and gas between the upper zone and the lower zone holding the catalyst bed; and (c) an upper zone holding the catalyst bed and the separating means. (D) a liquid inlet between the separation means and the lower zone holding the catalyst bed; and (e) a gas below the lower zone holding the catalyst bed. An outlet for liquid and an outlet for liquid or an outlet for liquid and gas, wherein in the vessel the liquid obtained from the outlet for liquid located below the lower zone holding the catalyst bed, the upper side holding the catalyst bed For transport to the liquid inlet located above the zone A reaction vessel suitable for hydrotreating, comprising means.