KR20140119046A - Process for hydrotreating a hydrocarbon oil - Google Patents

Abstract

The hydrocarbon oil comprises (i) providing a first stream of hydrogen-containing gas; (ii) hydrotreating the hydrocarbon oil with a first hydrotreating catalyst in the first reactor in the presence of a first stream of the hydrogen-containing gas as provided in step (i) to form a first effluent ; (iii) separating the first effluent as obtained in step (ii) into a hydrotreated hydrocarbon oil and a used hydrogen-containing gas using a stripping column using a hydrogen-containing gas as the stripping gas; (iv) providing a second stream of heated hydrogen-containing gas within a section of a heating device arranged upstream of the first reactor to obtain a heated hydrogen-containing gas stream; (v) optionally in the presence of at least a portion of the hydrotreated hydrocarbon oil as obtained in step (iii), in the second reactor, of the heated hydrogen-containing gas stream as obtained in step (iv) At least a portion of the hydrogen-containing gas stream used in contact with the second hydrotreating catalyst, and the hydrotreated hydrocarbon oil as obtained in step (iii), further comprising a further hydrotreated hydrocarbon oil Hydrogenating the hydrocarbon oil using at least a first reactor and a second reactor, comprising the steps of:

Description

PROCESS FOR HYDROTREATING A HYDROCARBON OIL <br> <br> <br> Patents - stay tuned to the technology PROCESS FOR HYDROTREATING A HYDROCARBON OIL

The present invention relates to a hydrotreating process for hydrocarbon oils using at least a first reactor and a second reactor.

Processes for hydrotreating hydrocarbon oils are well known. Processes using two or more reactors are also described in the literature.

Processes for reducing the amount of sulfur or nitrogen containing compounds and aromatics are generally referred to as hydrotreating processes. These processes are particularly processes relating to the saturation of unsaturated compounds such as aromatics and olefins, in this case processes which are referred to as hydrogenation processes, and in particular sulfur-containing compounds and often also simultaneously nitrogen- Processes for reducing the amount, in this case, can be further divided into processes, referred to as hydrodesulfurization processes. Particularly to reducing the amount of nitrogen containing compounds, wherein there are also processes wherein only relatively small amounts of sulfur-containing compounds are removed. These processes are called hydrodenitrogenation processes. In the context of the hydrodesulfurization processes used hereinafter, the processes are meant to relate to the removal of sulfur-containing compounds and optionally nitrogen. Processes in which linear waxy hydrocarbons are isomerized to branched alkanes are referred to as hydroisomerisation or hydrodewaxing processes. These processes can be applied to the intermediate distillate to reduce the pour point. Alternatively, the process may be applied to lubricants to improve the viscosity index.

A hydrogenation process using two reactors in series is described in WO 2011/006952 A2. It describes a hydrotreating process in which a combination of hydrocarbon oil and hydrogen-containing gas is passed through a first furnace and the heated combination is contacted with a hydrotreating catalyst in a first reactor vessel. This contact effluent is separated into partially hydrotreated hydrocarbon oil and contaminated hydrogen-containing gas. The separation is carried out in a stripping column using hydrogen as a stripping gas. The partially hydrotreated hydrocarbon oil is passed through a second furnace and the heated oil is contacted with the hydrotreating catalyst in a second reactor vessel in the presence of a hydrogen-containing gas. The product of this step is separated into a hydrotreated hydrocarbon oil and a used hydrogen-containing gas, where the hydrotreated hydrocarbon oil can be recovered as product and the used hydrogen-containing gas recycled to the stripping column.

Since the product properties require changes during the year in the sense that the cold flow properties of the product are less stringent during the summer than the other months of the year, the first and second hydrotreating steps are interestingly decoupled It is desirable to have a flexible hydrotreating process. The separation allows the use of the first reactor vessel only for summer only and the integrated use of the two reactor vessels for the remainder of the year. The main difficulty, however, is the initiation of the second hydrotreating step when it is necessary to reintegrate the two hydrotreating steps because the second reactor vessel may be easily damaged during the start-up process. It is an object of the present invention to provide a process that improves the economics of an integrated process while facilitating the coupling of two reactor vessels in an interesting manner.

Accordingly, the present invention provides a process for hydrotreating a hydrocarbon oil using at least a first reactor and a second reactor, wherein the hydrotreating of the hydrocarbon oil comprises:

(i) providing a first stream of hydrogen-containing gas;

(ii) hydrotreating the hydrocarbon oil with a first hydrotreating catalyst in the first reactor in the presence of a first stream of the hydrogen-containing gas as provided in step (i) to form a first effluent ;

(iii) separating the first effluent as obtained in step (ii) into a hydrotreated hydrocarbon oil and a used hydrogen-containing gas using a stripping column using a hydrogen-containing gas as the stripping gas;

(iv) providing a second stream of heated hydrogen-containing gas within a section of a heating device arranged upstream of the first reactor to obtain a heated hydrogen-containing gas stream;

(v) optionally in the presence of at least a portion of the hydrotreated hydrocarbon oil as obtained in step (iii), in the second reactor, of the heated hydrogen-containing gas stream as obtained in step (iv) At least a portion of the hydrogen-containing gas stream used in contact with the second hydrotreating catalyst, and the hydrotreated hydrocarbon oil as obtained in step (iii), further comprising a further hydrotreated hydrocarbon oil To obtain a second effluent.

DETAILED DESCRIPTION OF THE INVENTION

According to the invention, a second stream of clean hydrogen-containing gas is heated in a section of a heating apparatus arranged upstream of the first reactor to obtain a stream of heated clean hydrogen-containing gas.

Suitably, the hydrogen-containing first stream and / or the hydrocarbon oil are heated in the same heating apparatus before passing the heated combination through the first reactor. In a particular embodiment of the present invention, the hydrogen-containing first stream and the hydrocarbon oil are combined to heat in the lower section of the heating device before passing the heated combination through the first reactor, while the hydrogen- 2 stream is heated in the upper section of the heating device. In this way, the economics of the integrated process are considerably improved because a separate second furnace upstream of the second reactor vessel is no longer needed, while at the same time the use of the heating apparatus is such that the operation of the second reactor is isolated during the summer Up of the second hydrogen-containing gas in a substantially controlled and flexible manner when it is necessary to reintegrate the first reactor with the operation of the first reactor.

The present invention includes a warm-up step of a second reactor. During this step, the second stream of heated hydrogen-containing gas is passed to a second reactor, which can warm up and pressurize the second reactor in a controlled manner. When the second reactor is heated to the desired temperature, it can be pressurized. A further advantage of the present method is that during the warm-up of the second reactor, the hydrotreating catalyst in the second reactor is suitably reacted with the second stream of heated hydrogen- containing gas before reintegrating the second reactor to work with the first reactor . Suitably, the temperature of the reactor in the warm-up process is gradually increased. The increase in temperature may suitably be in the range of 5-40 캜 / hour. When the temperature is in the range of 240-350 占 폚, the second hydrotreating catalyst is suitably reacted for a period of 4 to 16 hours, preferably 6 to 10 hours, before the operation of the second reactor is reintegrated with the operation of the first reactor Can be reduced. Another advantage of the present method is that the second stream of heated hydrogen-containing gas strips hydrocarbon oil present on the second hydrotreating catalyst before separating the second reactor or replacing at least a portion of the second hydrotreating catalyst It can be used properly.

According to the present invention, the first stream of clean hydrogen-containing gas and the second stream of hydrogen-containing gas are preferably derived from the same source of clean hydrogen-containing gas. During periods when the second reactor can not be pressurized, a spare compressor may be used to circulate the hydrogen-containing gas stream.

In general, most of the amount, for example greater than 70% by weight, suitably greater than 80% by weight, and preferably greater than 90% by weight, is present in the liquid phase under the conditions of the first reactor- Lt; / RTI &gt; Hydrocarbon oils which may be suitably hydrotreated according to the present invention are kerosene fractions, gas oil fractions and lubricants. Particularly, gas oil fractions can be suitably applied to the present invention because they have an environmental restriction on gas oil. A suitable gas oil may be one of the majority of hydrocarbons, for example at least 75% by weight boiling in the range of 150 to 400 占 폚. Suitable lubricating oils contain at least 95% by weight of hydrocarbons boiling in the range of 320 to 600 占 폚.

The hydrotreating process may be a hydrofinishing process in which the hydrocarbon oil is subtlely changed, which may be a hydrocracking process in which the average number of carbon atoms in the oil molecule is reduced and the hydrogenation deasphalting process in which the metal component is removed from the hydrocarbon oil Which may be a hydrodemetallization process and may be a hydrogenation process in which the unsaturated hydrocarbons are hydrogenated and saturated and may be a hydrodewaxing process in which the straight chain molecules are isomerized or may be a hydrodesulfurization process in which the sulfur compounds are removed from the feedstock. The process has been found to be particularly useful when the hydrocarbon oil comprises sulfur compounds and the hydrotreating conditions include hydrodesulfurization conditions. The process is also very useful in the treatment of sulfur-containing hydrocarbon oils containing so-called refractory sulfur compounds, i.e. dibenzothiophene compounds.

The hydrotreating conditions that may be applied to the process of the present invention are not critical and may be adjusted according to the type of conversion to which the hydrocarbon oil is applied. In general, steps (ii) and step (v) the hydrotreating conditions are 250 to 480 ℃, preferably from 320 to 400 ℃ temperature in the range from 10 to 150bar, preferably between 20 and 90bar pressure and 0.1 in to 10hr ^{- 1} , preferably from 0.4 to 4 ^hr &lt; ^{-1 &} gt ;. The skilled artisan will be able to employ conditions depending on the type of feedstock and the desired hydrogenation treatment.

Preferably, the second stream of hydrogen-containing gas as provided in step (iv) contains less than 0.1% by volume of hydrogen sulphide.

The hydrotreating catalyst in step (ii) is suitably a hydrodesulfurization catalyst, and in step (v), the hydrotreating catalyst is suitably a hydrodewaxing catalyst.

Suitably, the hydrodesulfurization catalyst as used in step (ii) comprises, on a solid support, at least one metal from the group VB, VIB and VIII of the Periodic Table of the Elements.

Suitably, the hydrodewaxing catalyst as used in step (v) comprises, on a solid support, at least one noble metal from group VIII of the Periodic Table of the Elements as a catalytically active metal.

Suitable catalysts include, on a solid support, at least one Group VB, Group VIB and / or Group VIII metal of the Periodic Table of the Elements. Examples of suitable metals include cobalt, nickel, molybdenum and tungsten, as well as precious metals such as palladium or platinum. In particular, where the hydrocarbon oil comprises sulfur, the catalyst suitably contains a carrier and at least one Group VIB and Group VIII metal. While these metals may exist in their oxide form, it is desirable to use metals in their sulfide form. Since the catalyst can usually be prepared in the form of their oxides, the catalyst can then be applied to the pre-sulphidation treatment, which can be carried out ex situ, but preferably in situ, This is especially true in situations that resemble actual conversions.

The metals are suitably combined on the carrier. The carrier may be an amorphous refractory oxide, for example silica, alumina or silica alumina. Other oxides such as zirconia, titania or germania may also be used. Crystalline aluminosilicates such as zeolite beta, ZSM-5, mordenite, ferrierite, ZSM-11, ZSM-12, ZSM-23 and other mesoporous zeolites can be used for the hydrodewaxing process have. In cases where hydrotreating conditions involve hydrocracking, the catalyst may advantageously comprise different zeolites. Suitable zeolites are in the form of faujasite, for example zeolite X or Y, in particular superstabilized zeolite Y. Other preferred large pore zeolites are also possible. Zeolites are generally combined with amorphous binders, such as alumina. The metals are suitably combined with the catalyst by impregnation, dipping, co-mulling, kneading, and in the case of zeolites, by ion exchange. The skilled person is certain which catalysts are suitable and how the catalysts can be prepared.

The first hydrotreating catalyst and the second hydrotreating catalyst may be present in each reactor as one or more beds.

Suitably, at least a portion of the used hydrogen-containing gas stream as obtained in step (v) may be used as a stripping gas in step (iii).

Also, gaseous hydrocarbons that could be formed in the second hydrotreating reactor can be used for the stripping action. Moreover, since the used hydrogen-containing gas stream as obtained in step (v) appears from the second hydrotreating reactor, it becomes available in hydrotreating conditions, accompanied by an elevated temperature. The hydrogen-containing gas stream used at the elevated temperature will further facilitate the stripping action and improve the heat recovery from the used hydrogen-containing gas.

Suitably, the first stream and the second stream of the hydrocarbon-containing gas all comprise a clean hydrogen-containing gas. By "clean hydrogen-containing gas" is meant a gas containing less than 0.1 vol.%, Preferably less than 0.01 vol.%, More preferably less than 20 ppmv, and most preferably less than 5 ppmv of hydrogen sulfide, based on the total volume of gas I understand. Examples of clean hydrogen-containing gases include, for example, freshly replenished hydrogen prepared by steam reforming, or contaminated hydrogen-containing gas applied to a cleaning treatment with, for example, . Not only can the contaminated gas originate from the process, but contaminated hydrogen-containing gas from different sources or processes can be applied in the process for cleaning and subsequent use. The amount of hydrogen in the clean hydrogen-containing gas is preferably at least 95% by volume, more preferably at least 97% by volume, based on the total clean hydrogen-containing gas.

In a first embodiment, the hydrogen-containing gas used in step (ii) in the first reactor is a clean hydrogen-containing gas. This ensures that the amount of gas that needs to be fed to the first reactor can be minimized. The gas can be suitably obtained from a contaminated hydrogen-containing gas, for example, from the purification of such a contaminated gas which becomes available in the process.

In a preferred embodiment, the effluent from the first reactor is passed to a gas-liquid separator before using the stripping column. The gas phase in the effluent usually contains a large amount, for example 0.5 to 5.0% by volume of contaminants, for example hydrogen sulphide, based on the total volume of the gaseous phase. Thus, this phase can be recovered as a contaminated hydrogen-containing gas in the gas-liquid separator, and is preferably passed through a purification section, for example, an amine scrubber. The liquid phase containing the partially hydrotreated hydrocarbon oil is recovered from the gas-liquid separator and passed through a stripping column. The stripping column is operated from at least a portion of the used hydrogen-containing gas stream as obtained in step (v) from the second reactor. A combination of the used hydrogen-containing gas and the stripping gas stream as obtained in step (iii) may be fed to the first reactor as a hydrogen-containing gas. In this embodiment, it is certain that the first effluent is passed to the gas-liquid separator before using the stripping column. Most of the contaminants will be removed from the gas-liquid separator.

It will be appreciated that in the hydrotreating process of step (ii) and step (v), hydrogen is consumed. Generally, the hydrogen consumption for the hydrotreating step is not critical for the process and depends on the type of hydrocarbon oil being treated. Suitably, the hydrogen consumption in each reactor under the hydrotreating conditions is in the range of from 0.1 to 2.5% by weight, based on the weight of the hydrocarbon oil for the first reactor and the weight of the partially hydrotreated hydrocarbon oil for the second reactor to be. The hydrogen consumed in the first reactor and the second reactor suitably replenishes at least 80% by adding a clean hydrogen-containing gas to the second reactor. In this way, the amount of gas contaminated with a significant amount of contaminants in the first reactor is minimized. Further minimization can be suitably accomplished by replenishing at least 90%, more preferably substantially 100% of the hydrogen consumed in the first reactor and the second reactor with the second reactor by means of a clean hydrogen-containing gas.

The first effluent from the first reactor contains partially hydrotreated hydrocarbon oil. In step (iii), this partially hydrotreated hydrocarbon oil is separated from the contaminated hydrogen-containing gas. In useful embodiments, the treated hydrocarbon oil is usually a gas oil containing sulfur compounds. In the first reactor, these sulfur compounds are converted to hydrogen sulfide, which contaminates the hydrogen-containing gas. According to the method of the present invention, the contaminated hydrogen-containing gas is separated from the partially hydrotreated hydrocarbon oil in the stripping column in step (iii). In the stripping process, at least a portion of the hydrogen-containing gas, preferably the used hydrogen-containing gas stream as recovered from step (v), is used as the stripping gas. The contaminated hydrogen-containing gas thus obtained in the stripping column is appropriately cleaned and used again as a clean hydrogen-containing gas in step (v), and optionally step (ii).

Treatment of contaminated hydrogen-containing gases is well known, particularly when contaminated with hydrogen sulfide and other sulfur compounds, such as carbon disulfide or carbonyl sulfide. A suitable way of removing these contaminants is described briefly in EP-A 611 816 and is by means of an amine scrubber. Thus, the contaminated hydrogen-containing gas is preferably cleaned by treatment with an amine.

In this situation, the contaminated hydrogen-containing gas is in proper contact with the aqueous amine solution. The aqueous solution comprises one or more amine compounds. Suitable amine compounds are primary, secondary and tertiary amines. Preferably, the amines comprise at least one hydroxyalkyl moiety. The alkyl group in this part suitably contains one to four carbon atoms. In the case of secondary and tertiary amines, the amine compounds preferably comprise one or more alkyl and hydroxyalkyl groups, preferably one to four carbon atoms each. Suitable examples of amine compounds are monoethanolamine, monomethanolamine, monomethyl-ethanolamine, diethyl-monoethanolamine, diethanolamine, triethanolamine, di-isopropanolamine, diethylene glycol monoamine, methyldiethanolamine and And mixtures thereof. Other suitable compounds are N, N'-di (hydroxyalkyl) piperazine, N, N, N ', N'-tetrakis (hydroxyalkyl) -1,6- hexanediamine, And may contain four carbon atoms.

The aqueous solution may also contain a physical solvent. Suitable physical solvents include, but are not limited to, tetramethylenesulfone (sulfolane) and derivatives, amides of aliphatic carboxylic acids, N-alkylpyrrolidones, especially N-methylpyrrolidone, N-alkylpiperidones, Mono-or di (C ₁ -C ₄ ) alkyl ethers of ethylene glycol or polyethylene glycols, suitably having a molecular weight of 50 to 800, and mixtures thereof, such as ethylene glycol, propylene glycol, furidone, methanol, ethanol, ethylene glycol, polyethylene glycols.

The concentration of the amine compound in the aqueous solution may vary widely. The skilled person will be able to determine the appropriate concentration without undue burden. Advantageously, the aqueous solution comprises at least 15% by weight of water, 10 to 65% by weight, preferably 30 to 55% by weight of amine compounds and 0 to 40% by weight of the physical solvent, all% And the weight of the physical solvent.

The conditions under which the contaminated hydrogen-containing gas is appropriately treated by the amine include a temperature of 0 to 150 캜, preferably 10 to 60 캜, and a pressure of 10 to 150 bar, preferably 35 to 120 bar.

The stripping gas in the stripping column comprises a hydrogen-containing gas. At least a portion of the stripping gas may be available from the hydrotreating reaction of step (v) so that it becomes available at elevated temperatures. Since the temperature rise has an improved stripping performance against the stripping performance of the cold gas and counteracts the cooling effect of the stripping, it is clear that the process provides an additional advantage of obtaining an improved stripping action. The hydrogen-containing gas used as the stripping gas in step (iii) advantageously has a temperature of from 250 to 480 캜, preferably from 320 to 400 캜.

Some or all of the partially hydrotreated hydrocarbon oil is subjected to further hydrotreating in step (v). As indicated above, the process is particularly useful when the hydrocarbon oil to be treated is a gas oil. Thus, it is particularly preferred that the hydrotreating catalyst of step (ii) is a hydrodesulfurization catalyst, and that the hydrotreating catalyst of step (v) is a hydrodewaxing catalyst. In this case, the hydrodesulfurization catalyst suitably comprises on the solid support a selectively sulphated catalyst comprising one or more metals from group V, VI and VIII of the Periodic Table of the Elements. As indicated above, the solid carrier can be selected from any of the above-described refractory oxides. The hydrodesulfurization catalyst may in particular comprise at least one of metal nickel and cobalt, and at least one of metal molybdenum and tungsten. The catalyst may be usefully sulfated as described above.

The hydrodewaxing catalyst suitably comprises on the solid support one or more noble metals from Group VIII of the Periodic Table of the Elements as catalytically active metals. Preferably, the noble metal is selected from the group consisting of platinum, palladium, iridium and ruthenium. The carrier advantageously comprises a zeolite as described above together with a binder material. Suitable binder materials include alumina, silica, and silica-alumina. However, other refractory oxides may also be used.

As indicated above, the process may suitably be used during the initiation period of the second reactor or just before the second reactor is separated from the first reactor.

Thus, in one embodiment, the present invention provides a process for hydrotreating a hydrocarbon oil using at least a first reactor and a second reactor, the method comprising:

(i) providing a first stream of hydrogen-containing gas;

(ii) hydrotreating the hydrocarbon oil with a first hydrotreating catalyst in the first reactor in the presence of a first stream of the hydrogen-containing gas as provided in step (i) to form a first effluent ;

(iii) separating the first effluent as obtained in step (ii) into a hydrotreated hydrocarbon oil and a used hydrogen-containing gas using a stripping column using a hydrogen-containing gas as the stripping gas;

(iv) providing a second stream of heated hydrogen-containing gas within a section of a heating device arranged upstream of the first reactor to obtain a heated hydrogen-containing gas stream;

(v) contacting at least a portion of the heated hydrogen-containing gas stream in the second reactor as obtained in step (iv) with a second hydrotreating catalyst to obtain a used hydrogen-containing gas stream do.

In this embodiment, prior to (a) the start of the second reactor or (b) the stripping of the hydrocarbon oil from the second hydrotreating catalyst, the partially hydrotreated hydrocarbon oil is not passed to the second reactor I will understand.

The present invention also provides a hydrotreating process in which the operations of the first reactor and the second reactor are integrated.

Accordingly, the present invention, as a second aspect, provides a method for hydrotreating a hydrocarbon oil using at least a first reactor and a second reactor, the method comprising:

(i) providing a first stream of hydrogen-containing gas;

(ii) hydrotreating the hydrocarbon oil with a first hydrotreating catalyst in the first reactor in the presence of a first stream of the hydrogen-containing gas as provided in step (i) to form a first effluent ;

(iii) separating the first effluent as obtained in step (ii) into a hydrotreated hydrocarbon oil and a used hydrogen-containing gas using a stripping column using a hydrogen-containing gas as the stripping gas;

(iv) providing a second stream of heated hydrogen-containing gas within a section of a heating device arranged upstream of the first reactor to obtain a heated hydrogen-containing gas stream;

(v) at least a portion of the heated hydrogen-containing gas stream as obtained in step (iv) in the second reactor in the presence of at least a portion of the hydrotreated hydrocarbon oil as obtained in step (iii) Is contacted with a second hydrotreating catalyst to obtain a second effluent comprising the used hydrogen-containing gas stream and an additional hydrotreated hydrocarbon oil.

In step (vi), the hydrotreated second effluent of the second reactor can be recovered and separated into the hydrotreated hydrocarbon oil and the used hydrogen-containing gas stream. According to the present invention, in step (vii), at least a portion of the hydrogen-containing gas stream used may be passed to step (iii) for use as a stripping gas. Preferably at least 90% by volume of the hydrogen-containing gas stream used is transferred to step (iii), more preferably at least 95% by volume of the used hydrogen-containing gas stream, and most preferably, Is transferred to step (iii).

The separation in step (vi) can be carried out in any suitable manner. A suitable method involves the use of a separation device in a second reactor comprising a downwardly extending plate having an opening between the lower edge of the plate and the reactor wall. Preferably, a downwardly extending flange is provided at the lower edge of the plate. This follows a plate similar to that described in EP-A 611 861. Alternatively, different separation trays may be used in the lower portion of the second reactor. In a further embodiment, the separation of the hydrotreated effluent in the second reactor is optionally carried out in a separate gas-liquid separator, with additional thermal integration. Before or after separation, the effluent may be suitably used for heat exchange with the partially hydrotreated hydrocarbon oil discharged from the stripping column. This has the advantage that the partially hydrotreated hydrocarbon oil can be heated to the desired hydrotreating temperature without the use of additional furnaces, while the effluent is cooled. It will be clear that this represents a considerable economic and heat-efficient advantage.

Figure 1 shows a simplified flow diagram of two embodiments of the present invention.
Figure 2 shows a simplified flow diagram of a further embodiment of the present invention.

Figure 1 shows a line 1 in which hydrocarbon oil is passed through a heat exchanger 2 and a clean hydrogen-containing gas is passed upstream or downstream of the heat exchanger 2 via line 3e And added to the line (1). The combination of the hydrogen-containing gas and the hydrocarbon oil is passed through the lower section of the furnace 4 and the heated combination is passed through the line 5 to the first hydrotreating reactor 6. Three catalysts were provided in the first hydrotreating reactor (6). Between the subsequent layers, a quench, for example a clean hydrogen-containing gas, is added via lines 3c and 3d, respectively. In principle, the flow of the first reactor and the second reactor may be upward or downward. It is preferred to pass hydrogen-containing gas and hydrocarbon oil or partially hydrotreated hydrocarbon oil in parallel through the reactor vessels in the downflow direction. In this way, the gas flow and the liquid flow can be controlled in a reliable manner. In addition, the reaction temperature can be controlled more easily. The effluent from the first reactor is withdrawn via line (7). The effluent is also passed through a heat exchanger (2) to preheat the hydrocarbon oil to be treated and then passed to the stripping column (8). In the stripping column, the stripping gas in the form of the hydrogen-containing gas used is fed to the lower portion via line 10 and the gaseous component in the effluent from line 7, along with the stripping gas, As a contaminated hydrogen-containing gas. The contaminated hydrogen-containing gas is treated and purified in the amine absorption column 16, and the clean hydrogen-containing gas is recovered via line 3. The line 3 is divided into line 3a, line 3b and line 3e, line 3a introducing the hydrogen-containing gas to the hydrocarbon oil and line 3b being the line for the reactor temperature control 1 gas into the lines 3c and 3d to provide additional hydrogen to the reactor 1 and then the hydrogen-containing gas is heated in the upper section of the furnace 4 via line 3e. The thus obtained heated hydrogen-containing gas is then combined with the partially hydrotreated hydrocarbons of line 11 via line 14 and the combined stream thus obtained is passed through line 23 to the second reactor (12). While the amine absorption is shown in the figure as a single absorption column 16, it is understood that the amine treatment unit comprises an absorption and desorption column and, optionally, one or more compressors. In addition, the clean hydrogen-containing gas in line 3 can also be used to purify the effluent from the first reactor of one or more other process streams, e. G., The contaminated hydrogen-containing gas in line 9 and / As shown in FIG. The stripped, partially hydroprocessed hydrocarbon oil is discharged from the stripping column 8 via line 11, thereby closing the valve 17 during the combined operation of the two reactors. The partially hydrotreated hydrocarbon oil in line 11 may be passed to the second reactor 12. In accordance with the present invention, at least 80% of the hydrogen consumed in the reactor 6 and the reactor 12 will be added to the reactor 12. It will be clear to the skilled person that in some cases less than 20% of the freshly filled hydrogen, i. E., The hydrogen gas stream, can be replenished from the line 3 to the hydrogen-containing gas stream. The hydrocarbon oil treated from the reactor 12 is separated into a gas and a liquid stream either inside the reactor under the aid of a special separation tray 13 or in a separate knock-out drum. The gaseous components, i. E. The used hydrogen-containing gas, is recovered from the reactor 12 via line 10 which passes the used hydrogen-containing gas to the stripping column 8. The liquid hydrotreated hydrocarbon oil may be recovered via line (15). The product of line 15 may be fractionated in any known manner. During the initiation process of the reactor 12, the hydrocarbon oil is stripped from the catalyst in the reactor 12, or just before the separation of the reactor 12 in the event that the catalyst is replaced in the reactor 12, The gas can be introduced into the reactor 12 via line 14 while the flow of partially hydrotreated hydrocarbon oil can no longer be passed to the reactor 12 by the closing valve 20, The partially hydrotreated hydrocarbon oil can be recovered via line 21 via line valve 17. When the reactor 12 is completely separated from the reactor 6 and also the flow of hydrogen to the reactor 12 via line 14 will be stopped by the closing valves 19 and 22, The return of the effluent from the valve 18 will be stopped by the closing valve 18. In addition, at least a portion of the hydrogen-containing gas may bypass the furnace 4 via line 21 and valve 22, and may be combined with the heated hydrogen-containing gas of line 14.

In a further embodiment of the invention, shown in Figure 2, line 24 is added to circulate the hydrogen-containing gas stream. Valves 25 and 26 have been added. Line 3 is now divided into line 3e, line 3b and line 3a where line 3e leads to hydrogen-containing gas to hydrocarbon oil and line 3b to reactor temperature control Is subsequently divided into lines 3c and 3d to provide additional hydrogen to the first reactor 6 and the hydrogen-containing gas is heated in the upper section of the furnace 4 via line 3a. During periods when the second reactor can not be pressurized, a spare compressor may be used to circulate the hydrogen-containing gas stream via line 24 and shut-off valves 25 and 26.

Claims (13)

A method for hydrotreating a hydrocarbon oil using at least a first reactor and a second reactor,
(i) providing a first stream of hydrogen-containing gas;
(ii) hydrotreating the hydrocarbon oil with a first hydrotreating catalyst in the first reactor in the presence of a first stream of the hydrogen-containing gas as provided in step (i) to form a first effluent ;
(iii) separating the first effluent as obtained in step (ii) into a hydrotreated hydrocarbon oil and a used hydrogen-containing gas using a stripping column using a hydrogen-containing gas as the stripping gas;
(iv) providing a second stream of heated hydrogen-containing gas within a section of a heating device arranged upstream of the first reactor to obtain a heated hydrogen-containing gas stream;
(v) optionally in the presence of at least a portion of the hydrotreated hydrocarbon oil as obtained in step (iii), in the second reactor, the heated hydrogen-containing gas as obtained in step (iv) Wherein at least a portion of the stream is contacted with a second hydrotreating catalyst and wherein the hydrogenated hydrocarbon stream as obtained in step (iii), if present, is further hydrotreated hydrocarbons A process for hydrotreating a hydrocarbon oil, comprising the step of obtaining a second effluent comprising an oil. The method according to claim 1,
Wherein the first stream of hydrogen-containing gas and the second stream of hydrogen-containing gas are derived from the same source of clean hydrogen-containing gas. 3. The method according to claim 1 or 2,
Wherein the hydrocarbon oil to be hydrotreated is a gas oil containing at least 75 wt% of hydrocarbons boiling in the range of 150 to 400 캜. 4. The method according to any one of claims 1 to 3,
The step (ii) and hydrogenation conditions of 250 to 480 ℃ temperature range of step (v), from 10 to 150bar pressure and 0.1 to 10hr ^-, hydrocarbon group comprising from ¹ weight hourly space velocity (weight hourly space velocity) of A method of hydrotreating oil. 5. The method according to any one of claims 1 to 4,
Wherein the second stream of hydrogen-containing gas contains less than 0.1% by volume of hydrogen sulphide. 6. The method according to any one of claims 1 to 5,
Wherein the first effluent as obtained in step (ii) is passed to a gas-liquid separator prior to use of the stripping column. 7. The method according to any one of claims 1 to 6,
Wherein the used hydrogen-containing gas as obtained in step (iii) is cleaned and used again in step (v) and optionally in step (ii). 8. The method according to any one of claims 1 to 7,
Wherein step (v) is carried out in the presence of at least a portion of the hydrotreated hydrocarbon oil as obtained in step (iii). 9. The method according to any one of claims 1 to 8,
Wherein the hydrogen-containing gas used as the stripping gas in step (iii) has a temperature of 250 to 480 占 폚. 10. The method according to any one of claims 1 to 9,
Wherein the used hydrogen-containing gas as obtained in step (v) is used as a stripping gas in step (iii). 11. The method according to any one of claims 1 to 10,
Wherein the first hydrotreating catalyst of step (ii) is a hydrodesulphurization catalyst and the second hydrotreating catalyst of step (v) is a hydrodewaxing catalyst. 12. The method of claim 11,
Wherein the hydrodesulfurization catalyst as used in step (ii) comprises, on a solid support, one or more metals from Groups VB, VIB and VIII of the Periodic Table of the Elements. 13. The method according to claim 11 or 12,
Wherein the hydrodewaxing catalyst as used in step (v) comprises, on a solid support, at least one noble metals from Group VIII of the Periodic Table of the Elements as a catalytically active metal.

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