JP2003531275A - Production of low sulfur / low aromatic distillate - Google Patents

Abstract

  (57) [Summary] A process for producing a distillate boiling range stream in which both sulfur and aromatics are low. The distillate feed is treated in the first hydrodesulfurization stage in the presence of a hydrogen-containing process gas and a hydrodesulfurization catalyst, thereby resulting in partial desulfurization of this stream. This partially desulfurized distillate stream is then treated in the second hydrodesulfurization stage, also in the presence of a hydrogen-containing process gas and a hydrodesulfurization catalyst. The hydrogen-containing process gas is cascaded from the next downstream reaction stage. This stage is an aromatic compound hydrogenation stage.

Description

Detailed Description of the Invention

[0001]Cross-reference of related applications   This is US Provisional Patent Application No. 60/111, filed December 8, 1998.
US patent filed December 7, 1999 claiming priority from 346
It is a partial continuation application of application 09 / 457,434.

[0002]Field of the invention   The present invention is a distillate boiling range stream that is low in both sulfur and aromatics.
Concerning the generation method. This distillate feedstock contains hydrogen in the first hydrodesulfurization stage.
It is processed in the presence of a process gas and a hydrodesulfurization catalyst, which results in this stream.
This results in partial desulfurization of the rubber. This partially desulfurized distillate stream is then
In the second hydrodesulfurization stage, which is also a hydrogen-containing process gas and hydrodesulfurized.
It is processed in the presence of a sulfurization catalyst. This hydrogen-containing process gas is supplied from the third downstream reaction stage.
Cascaded. This reaction stage is an aromatic compound hydrogenation (hydrogenation) stage.
.

[0003]BACKGROUND OF THE INVENTION   Environmental and regulatory leaders are responsible for both sulfur and aromatics in distillate fuels.
We are constantly demanding lowering levels. For example, distillate fuel sold in the EU
Suggested sulfur limit for fuels for 2005 is less than 50 wppm
. Similarly, lower levels of total aromatics, as well as distillate fuels and
Require lower levels of polyaromatic compounds found in heavy hydrocarbon products
Restrictions are also proposed. In addition CARB standard diesel and Swedish   The maximum acceptable total aromatics level for Class I diesel is
They are 10% by volume (vol%) and 5% by volume, respectively. Furthermore, CARB standard fuel
Allows a polycyclic aromatic compound (PNA) of 1.4 vol% or less. But
Therefore, due to these proposed regulations, there are currently many
Is being studied.

Hydrotreating, or hydrodesulfurization in the case of sulfur removal, is well known in the art, generally treating a petroleum stream with hydrogen at hydrotreating conditions in the presence of a supported catalyst. There is a need to. The catalyst is usually composed of a Group VI metal with one or more Group VIII metals as cocatalysts on a refractory support. Particularly suitable hydrotreating catalysts for hydrodesulfurization as well as hydrodenitrogenation are generally VI
It includes molybdenum or tungsten as a Group VI metal on an alumina support, promoted with cobalt, nickel, iron, or a combination thereof as a Group II metal. Cobalt promoter molybdenum on alumina catalysts is most widely used when the limiting specification is hydrodesulfurization, while nickel promoter molybdenum on alumina catalysts is hydrodenitrogenated, partially aromatic saturated, And most widely used for hydrodesulfurization.

Similarly, much work is being done to develop more active catalysts and to design reactors to meet the demand for more effective hydrotreating processes. Various improved hardware arrangements have been proposed. One such arrangement is a co-current design in which the feed flows downward through the continuous catalyst bed and the process gas, which is typically a hydrogen-containing process gas, also flows in co-current with the feed. Another arrangement is a countercurrent design in which the feed flows downward through a continuous catalyst bed in countercurrent with the upwardly flowing process gas, which is typically a hydrogen-containing process gas. The catalyst bed downstream of the feed stream is high in performance but otherwise more sulfur sensitive (sulfur sensitive).
e) It may contain a catalyst. The reason is that the upwardly flowing process gas carries away heteroatomic constituents, which are harmful for sulfur and nitrogen sensitive catalysts, such as H ₂ S and NH ₃ .

Other process configurations include the use of multiple reaction stages, either in a single reaction vessel or in separate reaction vessels. The more sulfur sensitive catalysts can be used in the downstream stages as the level of heteroatom content decreases continuously. In this regard, European Patent Application No. 93200165.4 teaches a two-stage hydrotreating process carried out in a single reaction vessel.

Substantial hydrodesulfurization (HDS) and aromatics saturation (ASA) of distillate fuels
To obtain T), two process configurations are commonly used, both operating at relatively high pressure. One process configuration is a single-stage process with Ni / Mo or Ni / W sulfide catalysts operating at pressures above 800 psig. Pressures above 2,000 psig are required to obtain high levels of saturation.
The other process configuration is a two-step process in which the feedstock is first treated at moderate pressure over Co / Mo, Ni / Mo, or Ni / W sulfide catalysts to reduce heteroatom levels, On the other hand, aromatic compound saturation is hardly observed. After the first step, the product stream was stripped to remove H ₂ S, NH ₃ ,
And remove light hydrocarbons. The first stage product is then reacted at elevated pressure over a Group VIII metal hydrogenation catalyst to obtain aromatic saturation. Such a two-step process typically operates at 600-1,500 psig.

In view of the above, there is a need for an improved desulfurization / aromatic saturation process for treating a feed stream so that it can meet ever more stringent environmental regulations.

[0009]Summary of the invention   According to the present invention, a distillate feedstock having a sulfur content higher than 3,000 wppm.
A multi-stage hydrodesulfurization and hydrogenation method of   a) In the first hydrodesulfurization step, the raw material strike is performed in the presence of a hydrogen-containing process gas.
Reacting the ream, wherein the first hydrotreating step comprises one or more reaction zones,
The reaction zone is operated in the presence of a hydrodesulfurization catalyst under hydrodesulfurization conditions, which
To obtain a liquid product stream having a sulfur content of less than 3,000 wppm,
Process that occurs as   b) sending said liquid product stream to a first separation zone in said first separation zone
A vapor phase product stream and a liquid phase product stream are produced,   c) sending the liquid phase product stream to a second hydrodesulfurization stage;   d) In the second hydrodesulfurization stage, cascade from the next downstream stage here
Liquid phase formation in the presence of a hydrogen-containing process gas which has been or partially cascaded
The product stream is reacted and the second hydrodesulfurization step is performed under hydrodesulfurization conditions.
One or more reaction zones, each of which is operated as a hydrotreating catalyst.
A liquid product stream containing a bed and thereby having less than 100 wppm sulfur.
The resulting process,   e) passing the liquid product stream from the second hydrodesulfurization stage to the second separation zone.
And a vapor phase stream and a liquid phase stream are generated in the second separation zone.
Process,   f) collecting the vapor phase stream,   g) sending said liquid phase stream from step e) to an aromatics hydrogenation stage
And, and   h) in the aromatic compound hydrogenation step in the presence of a hydrogen-containing treat gas,
The liquid phase stream is reacted and the hydrogenation step is performed under aromatic compound hydrogenation conditions.
Aromatics containing one or more reaction zones that are operated as follows:
Includes a hydrogenation catalyst bed, which results in substantially reduced levels of sulfur and aromatic compounding.
Resulting in a liquid product stream having
To be done.

In a preferred embodiment of the invention, the liquid phase stream is contacted with steam before passing through the aromatics hydrogenation stage to strip dissolved gas from the gas phase.

In a preferred embodiment of the invention, the hydrogenation stage comprises two or more separate temperature zones, at least one of said temperature zones being at least 25 ° C. higher than one or more other reaction zones. Operated at low temperature.

In yet another preferred embodiment of the present invention, the hydrogenation stage is operated in countercurrent mode and the process gas flows countercurrently upward with respect to the downflow feed.

In another preferred embodiment, the invention further comprises at least a portion of this liquid product stream of step (h), (i) one or more lubricating aids, (i)
i) one or more viscosity modifiers, (iii) one or more antioxidants, (iv) one or more cetane improvers, (v) one or more dispersants, (vi) one or more low temperatures. Flow enhancer, (vii) one or more metal deactivators, (viii) one or more corrosion inhibitors, (ix) one or more detergents, and (x) one or more distillate oils or Also included is the step of combining with at least one selected from the group consisting of upgraded distillates.

In another embodiment, the present invention is a product produced according to the multi-stage hydrodesulfurization and hydrogenation process of said distillate feedstock.

[0015]Detailed Description of the Invention   A feedstock stream suitable for being processed to produce a low emission distillate fuel product
Mu is a petroleum-based raw material (raw material base material) that boils above the distillate range. Take
The feedstock is generally about 150 to about 400 ° C, preferably about 175 ° C to about 370 ° C.
It has a boiling range of. These feed streams are typically about 3,000 wppm
Contains more sulfur than. Non-limiting examples of such feed streams include barge
Distillate oil, light contact cycle oil, light coker oil, etc. are included. An oil refiner
Removing these types of feed streams by removing as much sulfur as possible
It is highly desirable to upgrade as well as saturate aromatic compounds.
Yes.

The process of the present invention can be better understood by the description of the preferred embodiment illustrated in FIG. 1 herein. Preferably, the process configuration shown in Figure 1 herein uses a one-through hydrotreating gas in at least one of these stages. (I) when all the hydrogen-containing treat gas introduced into the reactor is consumed therein, or (ii) the unreacted hydrogen-containing treat gas present in the vapor phase effluent of the reactor is the reaction gas. When removed from the vessel, this process gas is then referred to as the "one-through" process gas.

Preferably the first hydrodesulfurization stage reduces the levels of both sulfur and nitrogen. The sulfur level is less than about 1,000 wppm, more preferably about 500 w
Up to less than ppm. The second hydrodesulfurization stage reduces the sulfur level to about 100 wppm.
Lower to less than. The third stage, the aromatics hydrogenation stage, saturates a significant amount of aromatics and also further reduces sulfur levels to below about 50 wppm. In the practice of this invention, hydrogen in the process gas reacts with impurities and converts them into H ₂ S, NH ₃ and steam, which are removed as part of the vapor effluent, which hydrogen also Olefins and aromatics are also saturated. Miscellaneous reaction vessel internals, valves, pumps, thermocouples, heat transfer devices, etc. are not shown for simplicity. FIG. 1 shows a hydrodesulfurization reaction vessel R1 including reaction zones 12a and 12b. Each of these reaction zones consists of a bed of hydrodesulfurization catalyst. Although two reaction zones are shown, the reaction stage may include one reaction zone, or alternatively may include more than one reaction zone. The catalyst is preferably in the reactor as a fixed bed. However, other types of catalyst arrangements such as slurries or ebullated beds can also be used. Downstream of each reaction zone are non-reaction zones 14a and 14b. This non-reaction zone is generally free of catalyst. That is, it is an empty area within the vessel with respect to the catalyst. Although not shown, liquid distribution means may be provided upstream of each reaction stage as well. The type of liquid dispensing means is not considered to limit the practice of the invention, but tray arrays such as sieve trays, bubble cap trays or trays with spray nozzles, chimneys, tubes, etc. are preferred. A vapor-liquid mixing device (not shown) can also be used in the non-reaction zone 14a for the purpose of introducing quench fluid (liquid or vapor) for temperature control.

The feed stream is supplied via line 10 to the reaction vessel R1 with the hydrogen-containing process gas via line 16 cascaded from the second hydrodesulfurization reaction stage R2. The term "cascaded" when used in connection with a process gas
It means the treated gas stream which is separated from the vapor effluent of the first reaction stage and is then sent to the inlet of the second reaction stage without passing through the compressor. The second reaction stage may be upstream or downstream of the first reaction stage with respect to the liquid flow. In other words, the relative reaction conditions in the first and second reaction stages, and the associated separation zones, do not require increasing the pressure of the process gas in the vapor phase effluent of the first stage, and the vapors coming from the first stage. The process gas in the phase effluent is adjusted so that it will naturally flow to the second stage.

Although this is not required, all or a portion of the hydrogen-containing treat gas may also be conveyed via line 18 to the hydrodesulfurization reaction stage R1. This additional hydrogen-containing process gas is typically cascaded or also obtained from another essential oil process unit, such as a naphtha hydrorefiner. The vapor effluent from S1 is
(I) may be recycled via lines 20, 22 and 16 and (ii) carried away from the process via line 50, or (iii) (i)
And (ii) may be used in combination. The term "recycled" as used herein with respect to a hydrotreating gas is vapor from one stage passing through a gas compressor 23 to increase its pressure before being sent to the inlet of the reaction stage. It shall represent the hydrogen-containing process gas stream separated as effluent. It should be noted that the compressor also generally includes a scrubber to remove unwanted species such as H ₂ S from the hydrogen recycle stream. The feed stream and the hydrogen-containing treat gas pass cocurrently through one or more reaction zones of the hydrodesulfurization stage R1 to remove a significant amount of heteroatoms, preferably sulfur, from the feed stream. The first hydrodesulfurization stage preferably comprises a catalyst consisting of Co-Mo or Ni-Mo on a refractory support.

As used herein, the term “hydrodesulfurization” means that the hydrogen-containing treat gas is primarily for the removal of heteroatoms, preferably sulfur and nitrogen, and for any hydrogenation of aromatic compounds. Used in the presence of a suitable catalyst which is active. Hydrodesulfurization catalysts suitable for use in the reaction vessel R1 of the present invention include conventional hydrodesulfurization catalysts on relatively high surface area refractory support materials, preferably alumina, such as at least one Group VIII metal, preferably Is Fe, Co, or Ni,
More preferably Co and / or Ni, most preferably Co; and a catalyst consisting of at least one Group VI metal, preferably Mo or W, more preferably Mo. Other suitable hydrodesulfurization catalyst supports include refractory oxides such as silica, zeolites, amorphous silica-alumina, and titania-alumina. Additives such as P may be present. It is also within the scope of the invention that more than one type of hydrodesulfurization catalyst be used in the same reaction vessel and the same reaction zone. The Group VIII metal is typically about 2 to 20 wt% (wt).
%), Preferably in an amount in the range of about 4-15% by weight. The Group VI metal is generally present in an amount in the range of about 5-50% by weight, preferably about 10-40% by weight, more preferably about 20-30% by weight. All metal weight percentages are based on the weight of the catalyst. Typical hydrodesulfurization temperatures range from about 200 ° C to about 400 ° C.
And the total pressure is from about 50 psig to about 3,000 psig, preferably about 100 p.
sig to about 2,500 psig, more preferably about 150 to 500 psig. A more preferred hydrogen partial pressure is about 50 to 2,000 psig, most preferably about 75 to 800 psig.

The combined liquid / vapor phase product stream exits hydrodesulfurization stage R1 via line 24 and is sent to separation zone S1 where the liquid phase product stream is vaporized. Separated from the phase product stream. The liquid phase product stream is generally a stream having components that boil in the range of about 150 ° C to about 400 ° C, but does not have a higher upper boiling range than the feed stream. The vapor phase product stream is overhead recovered via line 20.

The liquid reaction product coming from the separation zone S1 is passed via line 26 to the hydrodesulfurization stage R2.
And is sent downward through the reaction zones 28a and 28b. The non-reaction area is 2
It is represented by 9a and 29b.

A hydrogen-containing treat gas is introduced via line 30 into reaction stage R2, which is cascaded from aromatics hydrogenation stage R3 and sent in cocurrent with the feed. The term "cascaded" as discussed, means that the process gas flows from a downstream reaction stage, such as a hydrogenation stage, to an upstream stage at the same or lower pressure, thus compressing this gas. It means there is no need. This is not required, but all or a portion of this process gas may be routed to R2 via line 32.
May be added to. This additional process gas may come from another essential oil process unit, such as a naphtha hydrogen refiner. It is preferable that the introduction rate of hydrogen contained in the process gas is not more than 3 times, more preferably less than about 2 times, and most preferably less than about 1.5 times the chemical hydrogen consumption rate of this rate. The feed stream and the hydrogen-containing treat gas pass cocurrently through one or more reaction zones of the hydrodesulfurization stage R2, preferably the feed stream is less than about 50 wppm sulfur, more preferably about 25 w.
Removes a significant amount of residual sulfur to the level of having less than ppm sulfur.

Suitable hydrodesulfurization catalysts for use in the reaction vessel R2 in the present invention include conventional hydrodesulfurization catalysts such as those described for use in R1. Noble metal catalysts may also be used, preferably the noble metal is selected from Pt and Pd, or combinations thereof. Pt, Pd, or a combination thereof, is generally present in an amount in the range of about 0.5-5% by weight, preferably about 0.6-1% by weight. Typical hydrodesulfurization temperatures range from about 200 ° C to about 400 ° C with total pressure of about 5 ° C.
0 psig to about 3,000 psig, preferably about 100 psig to about 2,500
0 psig, more preferably about 150-1,500 psig. A more preferred hydrogen partial pressure is from about 50 psig to about 2,000 psig, most preferably about 75 psig.
psig to about 1,000 psig. Preferably the R2 outlet pressure is about 500
psig to about 1,000 psig.

The reaction product coming from the second hydrodesulfurization stage R2 is sent via line 38 to the second separation zone S2. In this separation zone, the vapor product containing hydrogen is overhead recovered and sent to hydrodesulfurization stage R1 via lines 34 and 16 and / or recycled via lines 34 and 35, or both. is there. Alternatively, all or a portion of the S2 vapor product may be carried away from the process. The liquid fraction is sent via line 39 to the aromatics hydrogenation stage R3. Here it flows downward through reaction zones 36a and 36b. R
Non-reactive zones similar to the non-reactive zones in 2 and R3 are represented by 37a and 37b. Before being sent downwards through the reaction zone of R3, the liquid fraction is first
Contact may also be made in the stripping zone (not shown) to remove trapped vapor components from the liquid stream. For example, as the liquid product stream flows through the stripping zone, it may contain raw material impurities (
The hydrogen-containing process gas is contacted by flowing upward under conditions effective to transfer at least a portion of H ₂ S and NH ₃ ) from liquid to vapor.
At least about 80% of residual H ₂ S and NH ₃ , more preferably at least about 9
It is preferred that 0% is removed from the downflowing liquid stream. The contacting means may be any known vapor-liquid contacting means, such as Raschig rings, bar saddles, wire mesh,
It includes ribbons, open honeycombs, gas-liquid contact trays such as bubble cap trays, and other devices. It is also within the scope of this invention that the stripping zone may be part of the reaction vessel R3 or it may be a separate vessel. Although the drawings of the present invention show the hydrogenation stage operating in a countercurrent mode in which the process gas flows countercurrent to the feed stream, the hydrogenation stage may also be operated in a cocurrent mode. You should understand.

Fresh hydrogen-containing process gas is introduced into the reaction stage R3 via line 40 and is sent in countercurrent to the liquid reaction product stream. The process gas rate is preferably about 400-1,200 scf / bbl (standard cubic feet per barrel),
More preferably, it is about 500 to 1,000 scf / bbl. By introducing a clean process gas (a gas substantially free of H ₂ S and NH ₃ ), the reaction stage R3 has a reduced activity suppressing effect on the catalyst exerted by H ₂ S and NH ₃ and H ₂ It can be operated more efficiently by increasing the partial pressure. This type of multi-step operation is especially attractive for very deep removal of sulfur and nitrogen, or when more sensitive catalysts (ie hydrocracking, aromatic saturation, etc.) are used in the second reactor. is there. Another advantage of the present invention is that process gas rates are relatively low compared to more conventional processes. The use of relatively low process gas rates is primarily due to the use of already hydrotreated distillate feedstocks. Further efficiency is obtained by not requiring recirculation of process gas. In other words, in one embodiment the process gas is a once through process gas.

The liquid stream and process gas are sent countercurrently to one another through one or more catalyst beds, or reaction zones 36a and 36b. The resulting liquid product stream exits reaction stage R3 via line 42 and the hydrogen-containing vapor product stream exits reaction stage R3 and is cascaded via line 30 to reaction stage R2. The catalyst used in the reaction zone of this second reaction stage may be any suitable aromatic compound saturated catalyst. Non-limiting examples of aromatic hydrogenation catalysts include nickel, cobalt-molybdenum, nickel-molybdenum, nickel-tungsten,
And precious metal-containing catalysts. Noble metal catalysts are preferred. Non-limiting examples of noble metal catalysts include platinum and / or palladium based catalysts. It is preferably a suitable carrier material, typically for example alumina, silica, alumina-
It is supported on refractory oxide materials such as silica, porous diatomaceous earth, diatomaceous earth, magnesia, and zirconia. Zeolite supports can also be used. Such catalysts are generally susceptible to sulfur and nitrogen inhibition or reduced activity. The aromatic saturation step is preferably from about 40 ° C to about 400 ° C, more preferably from about 200 ° C to about 35 ° C.
0 ° C. temperature, about 100 psig to about 3,000 psig, preferably about 200 p
sig to about 1,200 psig pressure, about 0.3 V / V / Hr to about 10 V / V /
Operated at a liquid hourly space velocity (LHSV) of Hr, preferably about 1-5 V / V / Hr.

The drawings also show some options. For example lines 44 and 46
Can carry a quench fluid, which can be a liquid or a gas. Hydrogen is the preferred gas quench fluid and kerosene is the preferred liquid quench fluid.

Although the reaction stages used in the practice of the present invention are operated at temperatures and pressures that are suitable for the desired reaction, these are preferably process gases that cascade from R2 and R3 to R1, and at R2. Adjusted to provide a one-through process gas. For example, a general hydrogen treatment temperature is about 50 psig to about 3,000 p.
sig is about 20 ° C. to about 400 ° C., but the reaction conditions, especially the reaction pressure are
Generally, it is adjusted to provide the desired process gas stream to minimize or preferably eliminate the need for associated pressure control equipment, such as a compressor.

It is also possible that the hydrogenation stage comprises two or more reaction zones operating at different temperatures,
It is also within the scope of this invention. That is, at least one of these reaction zones is operated at a temperature that is at least 25 ° C., preferably at least about 50 ° C. lower than one or more other reaction zones. The final downstream reaction zone for the feed stream is
The reaction zone operated at the lower temperature is preferred.

For the purposes of hydrotreating, and in the context of the present invention, the terms “hydrogen” and “hydrogen-containing treat gas” are synonymous and may be pure hydrogen or for the intended reaction, A process gas stream comprising at least a sufficient amount of hydrogen plus one or more other gases (eg, nitrogen and light hydrocarbons such as methane) that do not interfere with or adversely affect these reactions or products. It may be a hydrogen-containing processing gas. Impurities such as H ₂ S and NH ₃ are undesirable and, if present in significant amounts, will usually be removed from the process gas before being fed to the R1 reactor. The process gas stream introduced into the reaction stage is
Preferably at least about 50 vol% hydrogen, more preferably at least about 7
It will contain 5 vol% hydrogen, most preferably at least about 95 vol% hydrogen. In an operation in which unreacted hydrogen in the vapor effluent of any particular stage is being used for hydrotreating at any stage, the vapor effluent of that stage will provide sufficient hydrogen for one or more subsequent stages. Sufficient hydrogen must be present in the fresh process gas introduced to the stage to be included. In one embodiment, all or part of the hydrogen required for the first stage hydrotreating (R1) is contained in the second stage vapor effluent fed to the first stage. The first stage vapor effluent is cooled and condensed, hydrotreated and relatively clean and heavier (
For example, C ₄₊ ) hydrocarbons are recovered.

The liquid phase in the reaction vessel used in the present invention generally consists primarily of the relatively high boiling point components of this raw material. The vapor phase is typically a mixture of hydrogen-containing treat gas, heteroatom impurities such as H ₂ S and NH ₃ , and lower boiling vaporization components in the fresh feed, as well as lighter products of the hydrotreating reaction. is there. If the vapor phase effluent requires further hydrotreating it may be sent to a vapor phase reaction stage containing an additional hydrotreating catalyst and subjected to hydrotreating conditions suitable for further reaction. . Alternatively, the hydrocarbons in the vapor phase product can be condensed by cooling the vapor and the resulting condensate liquid is recycled to either reaction stage if necessary. It is also within the scope of the present invention that feedstocks already containing suitably low levels of heteroatoms are fed directly to the reaction stage for aromatic saturation and / or decomposition.

In one embodiment, the liquid phase product of the present invention may be combined with other distillates or upgraded distillates. As discussed, these products are compatible with effective amounts of fuel additives such as lubricating aids, cetane improvers and the like. Preferably, the higher amount of product is combined with the lower amount of additive, but fuel additives may be used to the extent that fuel performance is not compromised.
The specific amount of any additive used will vary depending on the use of the product, but these amounts are generally 0.0 based on the weight of the product and additive.
It will be 5 to 2.0% by weight. However, it is not limited to this range. These additives can be used alone or in combination as desired.

As discussed, relatively low levels of sulfur and polyaromatic compounds (PN
A distillate fuel product characterized by having a relatively high ratio of A) and total aromatics to PNA may be formed according to such a process. Such distillate fuels can be used, for example, in compression-ignition engines such as diesel engines, especially so-called "lean mix" diesel engines. Such fuels are compatible with: That is, for example, (i) a NOx conversion exhaust gas catalyst with high sulfur sensitivity, (ii) engine exhaust gas particulate emission reduction technology including a particulate trap, and (iii) an automobile diesel system using a combination of (i) and (ii) Of the compression-ignition engine system. Such distillate fuels have moderate levels of total aromatics, reducing the production costs of cleaner burning diesel fuels, as well as minimizing the amount of hydrogen consumed in this process. Thereby reducing CO ₂ emissions.

[0035] In one embodiment, the distillate composition of the present invention comprises less than about 50 wppm, preferably less than about 25 wppm, more preferably less than about 10 wppm, and most preferably less than about 5 wppm sulfur. These are preferably about 5-15% by weight
And more preferably has a total aromatics content of about 10-15% by weight. The PNA content of the distillate product composition obtained by the practice of the present invention is less than about 1.5% by weight, preferably less than about 1.0% by weight, more preferably about 0.5% by weight. The aromatic compound to PNA ratio is at least about 11, preferably at least about 14, and more preferably at least about 17. In another embodiment, the aromatic compound to PNA ratio is from 11 to about 50, preferably 11 to about 30, more preferably 11
~ About 20.

The term PNA is intended to refer to polycyclic aromatic compounds defined as aromatic species having two or more aromatic rings, including their alkyl and olefin substituted derivatives. Naphthalene and phenanthrene are examples of PNAs. The term aromatic compound is intended to refer to a species that contains one or more aromatic rings, including its alkyl and olefin substituted derivatives. Therefore, naphthalene and phenanthrene are also considered aromatic compounds with benzene, toluene, and tetrahydronaphthalene. It is desirable to reduce the PNA content of the liquid product stream, because PNA contributes significantly to emissions in diesel engines. However minimizing hydrogen consumption for economic reasons, and it is likewise desirable to minimize the CO ₂ emissions associated with the production of hydrogen by steam reforming. The present invention therefore achieves both of these by obtaining a high aromatic to PNA ratio in the liquid product. The fuel produced in accordance with the present invention preferably boils in the range of about 190 ° C to 400 ° C. Fuels of the present invention having a total aromatics / PNA ratio> 11 can be prepared by blending a larger amount of a lighter substance containing monocyclic aromatics but little PNA. The fuel of the present invention also differs from these in the following points. That is, the T10 boiling point is higher than 200 ° C. and the API specific gravity is less than 43.

[0037]

【Example】

The following examples are given to illustrate the invention and should not be considered as limiting the scope of the invention.

[0038]Examples 1-3   A virgin distillate feedstock containing about 10,000 to 12,000 wppm sulfur,
In industrial hydrodesulfurization equipment (first hydrodesulfurization stage), ordinary industrial NiMo
/ Al_TwoO_Three(Akzo-Nobel KF-842 / 840) and CoMo / A
l_TwoO_Three(Akzo-Nobel KF-752) was used.
And processed under the following general conditions. That is, 300 to 350 psig; 15
0 to 180 psig outlet H_Two75% H_TwoProcessing gas: 500 to 700 SCF / B
Processing gas rate: 0.3 to 0.45 LHSV; 330 to 350 ° C.

The liquid product stream from this first hydrodesulfurization stage was used as the feed stream to the second hydrodesulfurization stage. The process conditions for this second hydrodesulfurization stage are also shown in Table 1 below. Industrial NiMo catalyst (2.6 wt% Ni and 1
Criterion C-411) containing 4.3 wt% Mo was used for all of these runs.

The liquid product stream coming from this second hydrodesulfurization stage was used as feed to the aromatics saturation stage. The catalyst used was Sy from Criterion.
It was ncat-4. The conditions and raw materials and product properties used are shown in Table 1 below.

Examples 1-3 demonstrate that products containing less than 50 ppm S can be produced. In this case, the introduction rate of hydrogen into the processing gas in the second reaction stage is 3 times or less the chemical hydrogen consumption rate. Examples 1-3 also have a total aromatics to PNA ratio of greater than about 11 and a T10 boiling point greater than 200 ° C, 5-1
It has been demonstrated that a product containing 5% by weight of aromatic compounds can be produced.

[0042]

[Table 1]

[0043]Comparative Examples A to E   Comparative Examples AE are all conventional fuels having less than 50 wppm sulfur (S).
Is. Comparative Examples A, B, C, and D are higher than 15 wt% total aromatics
Fuels with levels are listed, all with total aromatics to PNA ratio
Is less than 10, which is outside the scope of the present invention. Comparative Example E is less than 5% by weight
Very low total aromatics level and total aromatics greater than 25 vs. P
It is a Swedish Class 1 diesel with an NA ratio. 5% by weight
Products with full aromatics are outside the scope of this invention.

[0044]

[Table 2]

The areas in the boxes in Table 2 define the products of this invention. The total aromatics / PNA ratio may be greater than 30. It should be understood that the total aromatics / PNA ratio may exceed 30, even though the abscissa of Table 2 is omitted at 30 for clarity. Total aromatic compounds (5-15% by weight)
) And total aromatics / PNA standards, preferred products of the invention have sulfur (S) levels of less than about 50 wppm, T10 boiling points greater than 200 ° C., and API specific gravity of less than 43. The names "FIA", "MS", and "SFC" are well known in the art as analytical techniques. For example, "FIA
“” Represents fluorescence indicator analysis, “MS” represents mass spectrophotometry and “SFC” represents supercritical fluid chromatography.

[Brief description of drawings]

FIG. 1 herein shows one preferred process configuration for practicing the present invention to produce a low emission distillate fuel composition. This process configuration is 2
One hydrodesulfurization stage and one aromatic saturation stage are shown. FIG. 1 also shows a hydrogen-containing process gas that is cascaded from a downstream reaction stage to an upstream reaction stage.

FIG. 2 herein is a plot of data relating to some properties of the products produced by the practice of this invention. Total aromatics content is plotted against the ratio of total aromatics to polycyclic aromatics.

─────────────────────────────────────────────────── ─── Continued front page    (81) Designated countries EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, I T, LU, MC, NL, PT, SE, TR), OA (BF , BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, G M, KE, LS, MW, MZ, SD, SL, SZ, TZ , UG, ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AE, AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, CA, C H, CN, CU, CZ, DE, DK, EE, ES, FI , GB, GD, GE, GH, GM, HR, HU, ID, IL, IN, IS, JP, KE, KG, KP, KR, K Z, LC, LK, LR, LS, LT, LU, LV, MD , MG, MK, MN, MW, MX, NO, NZ, PL, PT, RO, RU, SD, SE, SG, SI, SK, S L, TJ, TM, TR, TT, UA, UG, UZ, VN , YU, ZA, ZW (72) Inventor Jung Henry             New Jersey, United States             07945, Mendham, Wexford             Drive 35 (72) Inventor Lewis, William, Ernest             70808, Louisiana, United States             Baton Rouge, North Fieldgue             Coat 6933 (72) Inventor Easino, Larry, Lee             77546, Texas, United States             Lenswood, San Joaquin Quimper             Kuway 2017 (72) Inventor Towberry, My Cher, Sue             70808, Louisiana, United States             Baton Rouge, Wickham Dry             Bug 7222 (72) Inventor Stanz, Gordon, Fred Eric             70816, Louisiana, United States,             Baton Rouge, Lake Lingham             Circle 12217 F-term (reference) 4H029 CA00 DA00 DA09 DA10

Claims (26)

[Claims] 1. A multi-stage hydrodesulfurization and hydrotreating process for a distillate feedstock having a sulfur content higher than 3,000 wppm, comprising: a) a first hydrodesulfurization step in the presence of a hydrogen-containing treat gas. The feedstream is reacted and the first hydrotreating stage comprises one or more reaction zones, each reaction zone being operated in the presence of a hydrodesulfurization catalyst at hydrodesulfurization conditions, whereby 3,000 wppm A step of resulting in a liquid product stream having a sulfur content of less than; b) sending said liquid product stream to a first separation zone, wherein said vapor phase product stream and liquid phase product stream are in said first separation zone. And c) sending the liquid phase product stream to a second hydrodesulfurization stage, and d) in the second hydrodesulfurization stage, where: One in which the liquid-phase product stream is reacted in the presence of a hydrogen-containing treat gas that is cascaded or partially cascaded from the stages, and the second hydrodesulfurization stage is operated at hydrodesulfurization conditions. Comprising the above reaction zones, each reaction zone comprising one hydrotreating catalyst bed, thereby resulting in a liquid product stream having less than 100 wppm of sulphur, e) said second hydrodesulfurization Sending the liquid product stream from the stage to a second separation zone to produce a vapor phase stream and a liquid phase stream in the second separation zone; f) collecting the vapor phase stream; g) Sending said liquid phase stream from step e) to an aromatics hydrogenation stage, and h) in said aromatics hydrogenation stage a hydrogen containing treatment. Reacting the liquid phase stream in the presence of gas, the hydrogenation stage comprising one or more reaction zones operating at aromatic compound hydrogenation conditions, each reaction zone containing one aromatic compound hydrogen; A liquid product stream comprising a hydrogenation catalyst bed, thereby having a substantially reduced level of sulfur and aromatics, and a hydrogen-containing product stream cascaded to an upstream hydrodesulfurization stage. A multi-stage hydrodesulfurization and hydrogenation method comprising: 2. The multi-stage hydrodesulfurization and hydrogenation process according to claim 1, wherein step d) is carried out such that the liquid product stream contains less than 50 wppm of sulfur. 3. The multi-stage hydrodesulfurization and hydrogenation process according to claim 2, wherein step d) is carried out such that the liquid product stream contains less than 25 wppm of sulfur. 4. The first and second hydrodesulfurization stage catalysts are selected from catalysts comprising at least one Group VI metal and at least one Group VIII metal on an inorganic refractory support. The multi-stage hydrodesulfurization and hydrogenation method according to claim 1. 5. The Group VI metal is selected from Mo and W, and the Group VI metal
The multistage hydrodesulfurization and hydrogenation method according to claim 4, wherein the Group II metal is selected from Ni or Co. 6. The multi-stage hydrodesulfurization and hydrotreatment of claim 1, wherein at least a portion of the vapor phase stream coming from the first separation stage is recycled to the first hydrodesulfurization stage. Method. 7. The multi-stage hydrodesulfurization and hydrotreatment of claim 1, wherein at least a portion of the vapor phase stream coming from the second separation stage is recycled to the first hydrodesulfurization stage. Method. 8. The introduction rate of the hydrogen portion of the processing gas into the second reaction stage is not more than three times the chemical hydrogen consumption rate in the second reaction stage.
The multistage hydrodesulfurization and hydrogenation method according to. 9. The multistage hydrogenation according to claim 8, wherein the introduction rate of the processing gas into the second reaction stage is not more than twice the chemical hydrogen consumption rate in the second reaction stage. Desulfurization and hydrogenation methods. 10. The second hydrodesulfurization stage comprises two or more reaction zones operated at different temperatures, at least one of the reaction zones being at least 25 more than one or more other reaction zones. The multi-stage hydrodesulfurization and hydrogenation method according to claim 1, which is operated at a temperature lower by 0 ° C. 11. The second hydrodesulfurization stage comprises two or more different reaction zones, at least one of said reaction zones operating at a temperature at least 50 ° C. lower than one or more other reaction zones. The multi-stage hydrodesulfurization and hydrogenation method according to claim 10, wherein 12. The multi-stage hydrodesulfurization and hydrogen according to claim 10, wherein the final downstream reaction zone of the second hydrodesulfurization stage with respect to the feed stream is a lower temperature reaction zone. Method. 13. The hydrogenation stage comprises two or more reaction zones operated at different temperatures, at least one of said reaction zones being at least 25 ° C. lower than one or more other reaction zones. The multi-stage hydrodesulfurization and hydrogenation method according to claim 1, wherein 14. The hydrogenation stage comprises two or more different reaction zones, at least one of said reaction zones being operated at a temperature at least 50 ° C. lower than one or more other reaction zones. 14. The multistage hydrodesulfurization and hydrogenation method according to claim 13. 15. The multi-stage hydrodesulfurization and hydrogenation process according to claim 13, wherein the last downstream reaction zone with respect to the feed stream is a lower temperature reaction zone. 16. The multi-stage hydrodesulfurization and hydrogenation process according to claim 1, wherein the hydrogen-containing process gas and the liquid phase stream of the aromatic compound hydrogenation stage flow countercurrent to each other. . 17. The liquid phase stream of step e) is sent to a stripping stage before it is sent to the aromatics hydrogenation stage, which is countercurrent in the substantial absence of catalyst. 17. The multi-stage hydrodesulfurization and hydrogenation process according to claim 16, characterized in that it is brought into contact with a flowing hydrogen-containing process gas. 18. A vapor phase stream coming from the second hydrodesulfurization reaction stage is cooled and a resulting condensed liquid stream is separated from a residual non-condensed stream, a portion of the condensed liquid stream comprising aromatic hydrogen. The multi-stage hydrodesulfurization and hydrogenation process according to claim 1, characterized in that it is combined with a liquid feedstock to the gasification stage. 19. The multi-stage hydrodesulfurization and hydrogenation method according to claim 1, wherein the aromatic compound hydrogenation catalyst is selected from a catalyst consisting of a noble metal on an inorganic refractory support. 20. The multi-stage hydrodesulfurization and hydrogenation method according to claim 19, wherein the noble metal is selected from Pt or Pd. 21. The multi-stage hydrodesulfurization and hydrogenation method according to claim 20, wherein the carrier is alumina. 22. The multi-stage hydrodesulfurization and hydrogenation method according to claim 20, wherein the carrier is a zeolite material. 23. A distillate fuel product produced by the multi-stage hydrodesulfurization and hydrogenation method of claim 1. 24. The liquid product stream of step (h), (i) one or more lubricating aids, (ii) one or more viscosity modifiers, (iii) one or more antioxidants, (Iv) one or more cetane improvers, (v) one or more dispersants, (vi) 1
One or more cold flow enhancers, (viii) one or more metal deactivators, (viii)
One or more corrosion inhibitors, (ix) one or more detergents, and (x) one or more distillates or at least one selected from the group consisting of upgraded distillates. The multi-stage hydrodesulfurization and hydrogenation method according to claim 1, further comprising a step of combining. 25. A distillate fuel product produced by the multi-stage hydrodesulfurization and hydrogenation process of claim 24. 26. The processing gas supplied to the aromatic compound hydrogenation step is a once-through processing gas.
The multi-stage hydrodesulfurization and hydrogenation method according to claim 1.