JPH0115557B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD OF THE INVENTION The present invention relates to a method for continuously producing feedstock oil suitable for producing needle coke. [Background of the Invention] Conventionally, needle coke has been widely used as an artificial graphite electrode material. Such needle coke is usually obtained by processing petroleum-based heavy oil by a delayed coking method to produce raw coke, and then calcining the raw coke. However, the production of such needle coke requires the use of carefully selected heavy oil as a raw material, and when an unsuitable raw material oil is used, only poor quality coke with a high amorphous content is obtained. do not have. Therefore, by adjusting relatively widely available heavy oil,
Several reforming methods have been proposed to obtain feedstock oil with properties suitable for needle coke production. One such reforming method involves mixing two or more types of heavy oils with different properties such as history and aroma, such as coal tar and petroleum heavy oil, and removing insoluble substances. It is known that the method of using residual oil as raw material oil is effective (for example,
26481, JP-A-49-11603, etc.). However, in such a method, the generation and removal of insoluble matter which causes poor quality needle coke is carried out by static sedimentation separation or centrifugation, and batch operations are required in either case. However, as is well known, batch operations are disadvantageous in that productivity is low and quality varies from batch to batch. [Summary of the Invention] The present invention has been made in view of the above-mentioned circumstances, and is a method of continuously producing raw material oil for needle coke production by mixing two or more of the above-mentioned heavy oils and separating and removing insoluble components. The purpose is to provide a method for adjusting the That is, the continuous production method of raw material oil for producing needle coke according to the present invention involves preparing a high-temperature heavy oil mixture consisting of at least two types of heavy oils, and further cooling this mixture to remove water from the heavy oil mixture. When continuously producing raw material oil for needle coke production by generating insoluble substances and removing these insoluble substances from the heavy oil mixture, a part of the produced raw material oil for needle coke production is extracted. The heavy oil mixture is cooled by circulating the circulating oil to the cooling step and bringing the flow of the circulating oil into contact with the flow of the heated heavy oil mixture. FIG. 1 is a process diagram showing the method of the present invention. As shown in FIG. 1, in the method of the present invention, first, petroleum-based normal pressure to reduced pressure direct current residual oil,
High temperature 200-390℃ consisting of at least two types of heavy oil selected from coal tar, petroleum-based naphtha cracking residue oil, thermal cracking residue oil, hydrocracking residue oil, etc.
Prepare a heavy oil mixture of Preparation of this high-temperature heavy oil mixture is preferably carried out by heating each of the component heavy oils in advance and then combining them (line blending); however, after mixing the component heavy oils, Alternatively, it may be carried out by heating while mixing. The hot heavy oil mixture is then cooled to a temperature below 100° C. to form insoluble materials in the heavy oil mixture. In the method of the present invention, this cooling step is performed by extracting a part of the raw material oil for needle coke production that has already been produced and using it as circulating oil, and bringing the flow of this circulating oil into contact with the flow of the high-temperature heavy oil mixture. To do this. The circulating oil needs to be cooled to about 50 to about 90°C before contacting the high-temperature heavy oil mixture, but the circulating oil naturally cools down to the above temperature range while moving through the circulation path. In such cases, forced cooling is not necessarily necessary. In addition, when the temperature of the circulating oil falls below approximately 50℃,
Unfavorable in terms of fluidity. The cooling step is preferably carried out by bringing the jet of the high-temperature heavy oil mixture and the jet of the circulating oil into countercurrent contact or collision. In this way, the high-temperature heavy oil mixture is rapidly cooled by the collision movement of the circulating oil and the heavy oil mixture, and the temperature conditions necessary for the generation of insoluble substances are satisfied, and the collision of the precipitated insoluble matter is Therefore, aggregation of insoluble matter is promoted. On the other hand, the insoluble substances precipitated and aggregated in this manner are successively separated and removed, and continuous preparation of raw material oil for needle coke production is achieved. [Specific Description of the Invention] Hereinafter, the method of the present invention will be described in more detail based on preferred specific examples thereof. FIG. 2 is a layout diagram of the main parts of an apparatus used to carry out the method of the present invention, and FIG. 3 is an overall layout diagram including the main parts shown in FIG. As shown in FIGS. 2 and 3, the apparatus for carrying out the method of the present invention has a cylindrical upper tank 1 and a lower tank 2 having approximately the same diameter and arranged approximately vertically. They are connected by a relatively small cylindrical pipe 3 having a diameter of 1/2 to 1/10, preferably 1/5 to 1/6. A single heavy oil introduction pipe 4 is introduced into the lower tank 2 through its side wall, and the lower tank 2 is connected to the lower tank 2 at its downstream end.
It opens upward toward the cylindrical tube 3 inside. Further, the upstream side of the introduction pipe 4 branches into introduction pipes 4a and 4b for respective raw material heavy oils relatively close to the lower tank 2.
b is the heater 5a or 5b and the pump 6, respectively.
via a or 6b, raw material heavy oil tank 7a
or bound to 7b. Further, a heavy liquid extraction pipe 8 is connected to the bottom of the lower tank 2.
is connected to a heavy liquid tank 10 via a pump 9. On the other hand, a light liquid extraction pipe 11 is connected to the upper part of the upper tank 1, and this extraction pipe 11 is connected to a product oil tank 14 via a receiving tank 12 and a pump 13. Further, a circulation pipe 15 is branched and connected downstream of the pump 13 of the extraction pipe 11.
5 extends into the upper tank 1 and opens downward toward the cylindrical pipe 3 within the upper tank 1. A cooler 16 is disposed in the middle of this circulation pipe 15. Also upper tank 1
Inside, from one side wall to the opposite side wall,
A plurality of substantially horizontal shelves 17 extend, the lower ones of which extend beyond the center of the tank 1 toward the opposite side walls. Moreover, heaters 20a and 20b are arranged around the bottoms of the tanks 1 and 2. Next, a typical embodiment of preparing raw material oil for producing needle coke using the above-mentioned apparatus will be described. In the following explanation, "part" and "%" are
Unless otherwise specified, measurements are based on weight. First, heavy oil A with relatively low aroma is pumped from tank 7a, and heavy oil B with relatively high aroma is pumped from tank 7b with pump 6a or 6b, respectively.
200 to 390 by heater 5a or 5b.
After heating to ℃, the two liquids are mixed just before the lower tank 2, and the two liquids are mixed through the introduction pipe 4 into the lower tank 2.
It flows out directly below the inner cylindrical pipe 3. The heavy oil A is, for example, petroleum-based normal pressure or vacuum direct distillation residue oil, and the heavy oil B is, for example,
Coal tar, petroleum naphtha cracking residue oil, thermal cracking residue oil, hydrocracking residue oil, etc. are used. It is preferable to use the heavy oil B in an amount of 30 to 70 parts per 100 parts of the mixed oil in consideration of the removal efficiency of insoluble substances and the properties of the product raw material oil. The introduced mixed oil is preferably heated to 100°C by contacting and mixing with the circulating light liquid cooled to 50 to 90°C, which rises mainly through the cylindrical pipe 3 and flows out through the circulation pipe 15 and the cooler 16. The insoluble substances generated by this series of mixing and cooling are accelerated to coagulation and sedimentation, flow down through the cylindrical pipe 3 in contact with the mixed oil, and flow down into the lower tank 2.
deposited at the bottom of the The heavy liquid mainly consisting of deposited insoluble substances is heated by the heater 20b and drawn out from the bottom pipe 8 while maintaining fluidity, and is retained in the storage tank 10 via the pump 9. On the other hand, the light liquid from which insoluble substances have been removed in the upper tank 1 further passes between the shelves 17 and rises, further separating the insoluble substances, and is extracted from the upper part of the upper tank 1 through the piping 11, and is then drawn out from the upper tank 1 through the pipe 11, The product oil is stored in a product oil tank 14 via a pump 13. Further, a part of the light liquid coming out of the pump 13 is circulated to the upper tank 1 via the piping 15, and is made to flow out under the shelf plate 17 in the upper tank 1. In the above, a preferred example of the method of the present invention and its operation mode have been explained based on a specific apparatus. However, those skilled in the art will readily understand that various modifications to the manufacturing method of the above example can be made within the scope of the present invention. For example, the raw material heavy oil is not limited to two types, but three or more types can be used. In addition, the raw material heavy oil introduction pipe 4 is extended into the lower tank 2, and the cylindrical pipe 3
Although it is preferable to make the opening directly below the lower tank 2, the present invention is not limited to this, and even if the opening is made in the side wall of the lower tank 2, a certain effect can be obtained. The introduction pipe 4 is also not limited to a single pipe,
A plurality of introduction pipes can be connected to the lower tank 2 or extended into the lower tank 2 for each raw material heavy oil. Furthermore,
Although the shelf board 17 in the upper tank 1 has the effect of promoting the separation of the light liquid and the insoluble substance, it is also preferable that the shelf board 17 be inclined diagonally downward in order to prevent the insoluble substance from being deposited on the shelf board 17. The volumes of upper tank 1 and lower tank 2 are:
In the above example, the volumes are approximately the same, but the ratio may be changed as appropriate in consideration of mixing and separation. As described above, according to the present invention, a method for continuously preparing a feedstock oil suitable for producing needle coke by mixing two or more types of heavy oil and separating and removing the produced insoluble substances is provided. A method for implementing the present invention is provided, and by using this method, it is possible to continuously and efficiently produce raw material oil for producing needle coke with stable quality. In particular, according to the method of the present invention, the high-temperature heavy oil mixture is rapidly cooled by the collision movement of the partially circulated product raw material oil and the heavy oil mixture, so that the temperature conditions necessary for the production of insoluble substances are satisfied. At the same time, the collision of the precipitated insoluble matter promotes its aggregation, and it becomes easy to set and control these temperatures. Furthermore, since the raw oils are mixed in the piping at high temperatures, and furthermore, the cooling and precipitation can be performed in a tank with a relatively large capacity, there is no problem of clogging of the piping by insoluble substances produced. EMBODIMENTS OF THE INVENTION In the following, practical examples of apparatus for use in the method of the invention are shown essentially as shown in FIGS. 2 and 3. Although the following example is a relatively small-scale example, it is believed that the effectiveness of the method of the present invention can be fully understood. Petroleum heavy oil A whose properties are shown in Table 1 below is 140
g/min, petroleum heavy oil B is fed at a rate of 60 g/min from feed pumps 6a, 6b, heaters 5a,
After heating each to 200℃ in 5b, pipe 4
a, 4b to join the pipe 4 just before the lower tank 2 (diameter approx. 250 mm, 40 mm), and pipe 3 in the lower tank 2 (approx.
mm, length 200 mm) from a position 100 mm directly below the bottom edge.

[Table] On the other hand, under the shelf board of the upper tank 1 (about 300 mm in diameter) equipped with shelf boards 17 (total of 5 pieces) as shown in the figure, piping 15,
A light liquid having a temperature of about 80°C was circulated through the cooler 16 at a rate of 1/min to rapidly cool the mixed oil to a temperature below 100°C. The light liquid extracted from the upper tank 1 is collected at a rate of 166 g/min (yield 83%) in the storage tank 14, while it is heated to about 200°C and flows from the bottom pipe 8 of the lower tank 2. A heavy liquid, consisting mainly of insoluble materials, was recovered. The recovered light liquid has a specific gravity of 0.967 and a residual carbon content of 9.2.
%, sulfur content 0.30%, toluene insoluble content 0.0%, aromaticity index 0.4, and molecular weight 465. Next, this light liquid was fed to a delayed coker device at a flow rate of 100 g/min (circulation ratio = 1).
It was coked in a cycle of 30 hours under a pressure of Kg/cm ² G. When the generated coke was observed under a polarizing microscope, it was observed that it had developed a needle-like structure, and as shown in Table 2, it was compared with the coking results of petroleum-based heavy oil alone.
The coke obtained using the light liquid prepared above had a higher coke specific gravity and was a so-called needle coke with a lower coefficient of thermal expansion.

【table】 [Brief explanation of drawings]

FIG. 1 is a process diagram showing an overview of the method of the present invention, FIG. 2 is a layout diagram of main parts of an embodiment of the apparatus used for carrying out the method of the present invention, and FIG. 3 is a diagram showing the main parts shown in FIG. FIG. 1... Upper tank, 2... Lower tank, 3... Cylindrical pipe, 4...
Heavy oil introduction pipe, 4a, 4b...Heavy oil introduction branch pipe, 8...Heavy liquid extraction pipe, 11...Light liquid extraction pipe, 1
5...Light liquid circulation piping, 16...Cooler, 17...
Shelf board.

Claims (1)

[Claims] 1. An insoluble substance is produced in the heavy oil mixture by preparing a high-temperature heavy oil mixture consisting of at least two types of heavy oil, and further cooling this mixture, and the insoluble substance is When continuously producing raw material oil for needle coke production by removing it from the heavy oil mixture, a part of the produced raw material oil for needle coke production is extracted and circulated to the cooling process, and this circulating oil is A method for continuously producing raw material oil for producing needle coke, characterized in that the heavy oil mixture is cooled by bringing the flow of the above into contact with the flow of the high-temperature heavy oil mixture. 2. The temperature of the high-temperature heavy oil mixture is 200 to 390°C, and further cooling is performed at a temperature of 100°C or less,
A method according to claim 1. 3. The method according to claim 1, wherein the heavy oil mixture is cooled by countercurrently colliding a jet of the hot heavy oil mixture with a jet of circulating oil. 4. Before bringing the circulating oil into contact with the heavy oil mixture,
2. The method of claim 1, wherein the circulating oil is previously cooled to about 50 to about 90<0>C. 5. The method according to claim 1, wherein the high-temperature heavy oil mixture is prepared by heating at least two types of heavy oil in advance and then combining them. 6. The claimed invention, wherein the at least two types of heavy oils are selected from the group consisting of petroleum-based atmospheric or vacuum direct distillation residue oil, coal tar, naphtha cracking residue oil, thermal cracking residue oil, and hydrocracking residue oil. The method described in Scope No. 1.