JP3411998B2 - Method for producing low sulfur gas oil - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to a process for producing gas oil for low sulfur diesel engines from petroleum fractions.

[0002]

2. Description of the Related Art The whole gas oil fraction (boiling point range called straight-run gas oil having a boiling point range of 150 to 400 ° C.) distilled by an atmospheric distillation apparatus is hydrodesulfurized, and this desulfurized gas oil is not desulfurized straight-run gas oil. A distillate, a straight-run kerosene fraction, and a cracked gas oil fraction obtained from a cracker for heavy fractions are mixed to produce gas oil having a sulfur content of 0.2% or less. However, as the exhaust gas regulations for large vehicles will be tightened in the future, this sulfur content regulation value will be 0.05%.
It is supposed to be lowered to.

[0003]

In the prior art, unless the temperature of the desulfurization reaction is raised or the time of the desulfurization reaction is lengthened, a gas oil having a sulfur content of 0.05% or less cannot be finally obtained. However, the reaction temperature cannot be increased because the hue of the light oil of the product is deteriorated when the reaction temperature is increased. Therefore, there is no other choice but to take a method of lengthening the desulfurization reaction time, which is another means. In other words, there is a problem that the liquid superficial velocity (LHSV) becomes small, the volume of the reaction column becomes large, the amount of the hydrodesulfurization catalyst used becomes large, and the desulfurization cost becomes high if the processing capacity is the same.

An object of the present invention is to produce a light oil having a low sulfur content without deteriorating the hue. An object of the present invention is to reduce the amount of desulfurization catalyst used and the amount of hydrogen consumed.

[0005]

SUMMARY OF THE INVENTION The above objects are primarily in gas oil
As a result, sulfur compounds and hydrogen in the light content are reacted in the presence of a catalyst.
And the first step of desulfurization and treatment in this first step
The second step of fractionating the gas oil that has been
Sulfur compounds and hydrogen in the heavy fraction fractionated in the second step
And a third step of reacting and in the presence of a catalyst to desulfurize .

[0006] The above-mentioned object is mainly in light components in light oil.
In the presence of a sulfur compound and hydrogen in the presence of a catalyst, the temperature is 280 to 3
The reaction is carried out at 80 ° C. and a pressure of 10 to 80 kg / cm ² , and the reaction is removed.
The first step of sulfurization and the light oil treated in this first step
In the second step of fractionating into mass and heavy fraction, and in this second step
The sulfur compound and hydrogen in the heavy fraction fractionated are used as a catalyst.
In the presence, the temperature is 150-360 ° C and the pressure is 10-80K.
The third step of reacting and desulfurizing at g / cm ² is achieved.

The above-mentioned object is to control the sulfur compound and hydrogen in light oil in the presence of a catalyst at a temperature of 280 to 380 ° C. and a pressure of 10 to 10.
A first step of reacting at 80 Kg / cm ² and a gas oil heavy oil containing a fraction having a boiling point of 330 ° C. or higher from the fluid from the first step.
A second step of separating the mass into a high-temperature gas-liquid, and the second step before
Captures serial diesel heavies, the temperature of the sulfur compounds and hydrogen of the gas oil heavy component in the presence of a liquid superficial velocity smaller than a catalytic amount of the first step is 150 to 360 ° C., a pressure from 10 to 80
A third step of reacting in kg / cm ^2, is achieved by having a.

[0008]

The boiling point of dibenzothiophene and alkyldibenzothiophenes, which are difficult to desulfurize among sulfur compounds contained in light oil, is 330 ° C. or higher. Further, the boiling points of benzothiophene and alkylbenzothiophenes in which the desulfurization reaction easily proceeds are mainly 330 ° C. or lower. Therefore, boiling point 330
Fractions below ℃ can be hydrodesulfurized with a short residence time.
Fractions above 30 ° C require long residence times. Therefore, the raw gas oil is desulfurized in the first step with a short residence time to prevent the deterioration of the hue, the distillate having a boiling point of 330 ° C. or higher is subjected to high temperature gas-liquid separation in the second step, and the desulfurization reaction is difficult in the third step. Only a distillate having a boiling point of 330 ° C. or higher containing a sulfur compound can be desulfurized over a long residence time to produce a light oil having a low sulfur content.
In the third step, the reaction temperature is lower than that in the first step, and the boiling point is 33
Since the proportion of the fraction of 0 ° C or higher in all the light oils of the product is small, the hue is less deteriorated.

Further, in the conventional two-stage hydrodesulfurization method, since all feed gas oils are treated for a long residence time according to the hardly desulfurizable sulfur compound, the amount of the catalyst used is large and the easily desulfurizable compound and the aromatic compound having a low boiling point are used. Compounds (indene, alkylindenes,
(Naphthalene, alkylnaphthalenes, fluorene, etc.) are excessively hydrogenated and hydrogen consumption increases, but with the above configuration, the first step with a large amount of treatment is performed with a short residence time, and the third step with a long residence time is treated with a treatment amount. Since the amount of hydrogen is small, the amount of catalyst used as a whole can be reduced and the amount of hydrogen consumption can be reduced.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

First, the devices that make up the process will be described.

FIG. 1 is a process flow sheet for explaining the configuration of the embodiment of the present invention.

As shown in the figure, 1 is a first reactor, 2 is a first heat exchanger, 3 is a first gas-liquid separator, 4 is a second reactor, 5
Is a second heat exchanger, 6 is a second gas-liquid separator, 7 is a third heat exchanger, and 8 is a third gas-liquid separator.

Next, the process flow will be described.

As the raw material, a straight-distilled gas oil (boiling point range of about 150 to 400 ° C.) distilled by an atmospheric distillation apparatus and a cracked gas oil obtained from a heavy oil cracking apparatus were mixed with a sulfur content of 0.
9 wt% mixed gas oil is used. The feed gas oil is fed from a feed gas oil tank (not shown) to a reaction pressure by a feed pump, and is heated and supplied to the first reactor 1 together with hydrogen gas by a heating means (not shown). The reaction conditions in the first reactor 1 are a temperature of 280 ° C. to 380 ° C. and a pressure of 10 to 80 kg.
/ Cm ² the catalyst is a porous carrier such as alumina, silica, titania, zirconia or a mixed oxide of V, M
A material carrying an active metal such as o, W, Ni, Co, Pd, Pt, Re, Ru or Rh is used. The gas-liquid mixed fluid from the first reactor 1 is controlled by the first heat exchanger 2 to a temperature necessary for high-temperature separation, and the first gas-liquid separator 3 is hydrogen, hydrogen sulfide, and a fraction having a boiling point of 330 ° C. or lower. And a liquid phase of a fraction having a boiling point of 330 ° C. or higher. Gas-liquid separation in the first gas-liquid separator 3 includes temperature, pressure and hydrogen, hydrogen sulfide,
It is carried out by vapor-liquid equilibrium determined by the vapor-liquid equilibrium coefficient of each component of the fraction having a boiling point of 330 ° C or lower, the fraction of the boiling point of 330 ° C or higher, and the vapor-liquid molar ratio, and the boiling point of 330 even under a pressure of 10 to 80 kg / cm ^2. Since the partial pressure of the fraction having a temperature of ℃ or less (pressure × the number of moles of the fraction having a boiling point of 330 ° C or less / the number of moles of the entire gas phase) is low, the temperature is appropriately determined in the first heat exchanger so that The distillate becomes vapor and can be separated into gas and liquid. First gas-liquid separator 3
The fraction having a boiling point of 330 ° C. or higher in the liquid phase separated in step 2 is supplied to the second reactor 4 together with new hydrogen gas. Second reactor 4
The reaction conditions are as follows: temperature 150-360 ° C., pressure 10-
At 80 kg / cm ² , the same catalyst as used in the first reactor 1 is used. The gas-liquid mixed fluid from the second reactor 4 is controlled by the second heat exchanger 5 to a temperature suitable for the subsequent process,
The second gas-liquid separator 6 separates the heavy gas oil having a boiling point of 330 ° C. or higher as a main component and unreacted hydrogen and off-gas composed of hydrogen sulfide. On the other hand, in the gas phase composed of hydrogen, hydrogen sulfide, and vapors of the fraction having a boiling point of 330 ° C. or lower separated by the first gas-liquid separator 3, only the fraction having a boiling point of 330 ° C. or lower is liquefied by the third heat exchanger 7. Cooled to temperature, third gas-liquid separator 8
And light gas oil whose main component is a fraction having a boiling point of 330 ° C or less
It is separated into unreacted hydrogen and off-gas composed of hydrogen sulfide. The light gas oil whose main component is the fraction having a boiling point of 330 ° C. or lower, which is separated by the third gas-liquid separator 8, has the main component of the fraction having a boiling point of 330 ° C. or more, which is separated by the second gas-liquid separator 6. Light sulfur produced by hydrocracking in a stripper (not shown) after being blended with heavy gas oil and stripped with hydrogen sulfide are stored in a product tank as low sulfur gas oil until shipment. The off gas separated by the second gas-liquid separator 6 and the third gas-liquid separator 8 is supplied to the first reactor 1 by removing hydrogen sulfide by a gas scrubber (not shown) and replenishing hydrogen newly.

Next, the reaction conditions will be specifically described.

Example 1 Sulfur content of a mixture of straight run gas oil and cracked gas oil as a raw material was 0.1
Hydrodesulfurization was performed under the reaction conditions shown in Table 1 using 9 wt% of mixed gas oil. The catalyst was a cylinder type or trilobe type pellet, and 10 to 30 cc was diluted with a double amount of carborundum.

[0018]

[Table 1]

Table 2 shows the properties and process characteristics of the product gas oil mixed with the hydrodesulfurized gas oil in each reactor.

[0020]

[Table 2]

As described above, according to this embodiment, a light oil having a sulfur content of 0.05 wt% or less can be produced without causing a decrease in hue. Further, cracked gas oil containing a large amount of hardly desulfurizable sulfur compounds, which is difficult to desulfurize by the conventional technique, can be mixed with the raw material and treated.

Then, the reactor volume, that is, the amount of catalyst can be reduced, and the hydrogen consumption can be reduced.

[0023]

EFFECTS OF THE INVENTION According to the present invention, a boiling point of 330 containing a sulfur compound in which a raw gas oil is hydrodesulfurized and the desulfurization reaction is difficult to proceed.
By distilling the distillate having a temperature of ℃ or higher at a high temperature to hydrodesulfurize, it is possible to prevent the deterioration of the hue and produce a light oil having a low sulfur content.

Further, by carrying out the first hydrodesulfurization with a short residence time and hydrodesulfurizing only the fraction having a boiling point of 330 ° C. or higher with a long residence time, the amount of catalyst used and the amount of hydrogen consumption can be reduced.

[Brief description of drawings]

FIG. 1 is a process flow sheet illustrating a configuration of an example of the present invention.

[Explanation of symbols]

1st reactor 2 First heat exchanger 3 First gas-liquid separator 4 Second reactor 5 Second heat exchanger 6 Second gas-liquid separator 7 Third heat exchanger 8 Third gas-liquid separator

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiharu Inaba 1 Yawata Kaigan Dori, Ichihara City, Chiba Mitsui Engineering & Shipbuilding Co., Ltd. Chiba Works (56) Reference JP-A-6-25677 (JP, A) JP-A 4-46993 (JP, A) JP-A-5-311179 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C10G 65/04

Claims (2)

(57) [Claims] 1. A sulfur compound mainly in light components of light oil.
First step of desulfurization by reacting hydrogen with hydrogen in the presence of a catalyst
And the light oil treated in the first step into light and heavy components
Second step of fractionating, and the heavy material fractionated in the second step
By reacting sulfur compounds in the minute with hydrogen in the presence of a catalyst
And a third step of desulfurizing, which is a method for producing low-sulfur gas oil. 2. A sulfur compound mainly in light components of light oil.
And hydrogen in the presence of a catalyst at a temperature of 280 to 380 ° C and a pressure of
Desulfurization by reacting with a force of 10 to 80 Kg / cm ²
Process, and the light oil treated in the first process as light and heavy components
The second step of fractionating into
In the presence of a catalyst, the temperature of sulfur compounds and hydrogen in heavy
150 to 360 ° C., a pressure reaction at 10~80Kg / cm ²
And a third step of desulfurizing the same, thereby producing a low-sulfur gas oil.