JPS62124191A - Method for thermal cracking treatment of petroleum heavy oil - Google Patents

Abstract

PURPOSE:To carry out thermal cracking treatment while preventing coking trouble of petroleum heavy oil and to produce pitch suitable as a fuel and a lightened cracked oil, by using a combination of a thermal cracking furnace and one completely blending type reactor. CONSTITUTION:A petroleum heavy oil is subjected to thermal cracking treatment in a ratio of >=50% total thermal cracking reaction ratio by a thermal cracking furnace 1 and both liquid pitch suitable as a fuel having 30-45wt% volatile content and a gaseous reaction product containing a cracked light oil are produced by a completely blending type reactor 2. Then, a cracked heavy oil having >=340 deg.C boiling point range formed from the above-mentioned process is preferably circulated to the petroleum heavy oil.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for continuous thermal decomposition treatment of petroleum heavy oil.

[Prior art]

Various methods are known for pyrolyzing heavy petroleum oil to produce gaseous products including liquid pitch and cracked light oil.
For example, according to Japanese Patent Application Laid-Open No. 59-157180, in order to obtain pitch and cracked light oil suitable as fuel, heavy oil is It has been proposed to treat pyrolysis. Although this method has the advantage of being able to carry out the thermal decomposition reaction continuously and effectively preventing coking 1-rubble, it uses two or more complete mixing reactors and the temperature of each reactor is controlled. Since it is necessary to set the temperature higher in the later stages, it has not yet been satisfactory in terms of device efficiency and economical efficiency.

〔the purpose〕

The present invention provides a method for pyrolysis treatment of petroleum heavy oil that overcomes the above-mentioned drawbacks found in the prior art, that is, a method for thermally cracking petroleum heavy oil using a combination of a cracking heating furnace and one complete mixing reactor. The purpose of the present invention is to provide a method for thermally decomposing oil while preventing coking troubles and producing pitch and lightened cracked oil suitable as fuel.

〔composition〕

According to the present invention, when thermally cracking petroleum-based heavy oil, the heavy oil is treated using a combination of a cracking heating furnace and one complete mixing reactor, and in the cracking heating furnace. A gaseous product containing liquid pitch suitable as a fuel with a volatile content of 30 to 45% by weight and cracked light oil in the complete mixing reactor, which is subjected to thermal decomposition treatment at a rate of 50% or more of the total thermal decomposition reaction rate. Provided is a method for pyrolysis treatment of petroleum-based heavy oil, which is characterized by producing a product.

Examples of the petroleum-based heavy oil used in the present invention include residual oils obtained from normal pressure or vacuum distillation of crude oil, various thermal decomposition residual oils, solvent deasphalted asphalt, natural asphalt, oil refinery residues obtained from tar sands, and the like. .

In the present invention, such petroleum-based heavy oil (hereinafter also simply referred to as feedstock oil) is thermally decomposed using a combination of a decomposition heating furnace and one complete mixing reactor. That is, the raw material oil is first subjected to thermal decomposition treatment using a decomposition heating furnace, and then the obtained thermal decomposition treatment product is further subjected to thermal decomposition treatment using one complete mixing reactor. When raw oil is pyrolyzed using a combination of such a cracking heating furnace and one completely mixed reaction group, in the conventional technology, the mesophase formed in the pitch in the completely mixed reactor is However, there was a problem that coking troubles were likely to occur because the proportion of these particles was high and they tend to coalesce into mesophases with a large particle size, that is, they tend to precipitate carbon.
According to the research of the inventors, the problem of coking trouble in this case can be effectively prevented by performing thermal decomposition treatment at a rate of 50% or more of the total thermal decomposition reaction rate in a decomposition heating furnace. discovered.

In addition, the prethermal decomposition reaction rate referred to in this specification means the total thermal decomposition reaction rate of the feedstock oil achieved by both the decomposition heating furnace and the complete mixing reactor, and is defined by the following formula. .

(A-C) R = -X, 100 (%) (■) R: Total thermal decomposition reaction rate (%) A: Weight of components with a boiling point of 538°C or higher in the feedstock C: Obtained from a complete mixing reactor Boiling point 5 in the thermal decomposition product
Weight B of components with a boiling point of 538°C or higher B: weight ratio (%) of components with a boiling point of 538°C or higher in the pyrolysis product obtained from the decomposition heating furnace In the present invention, the specific value of the total pyrolysis reaction rate is: Although it is set within an appropriate range depending on the type of raw material oil, generally speaking, the thermal decomposition reaction rate required to obtain pitch with a volatile content of 30 to 45% by weight is usually 65 to 75%, especially 65 to 75%. 6
It is in the range of 7-70%.

Generally, the reaction conditions in the decomposition heating furnace are: temperature: 450 to 520°C, pressure crab normal pressure to 20 kg/cn.
? Condition G is adopted. In this decomposition heating furnace, as described above, the total thermal decomposition reaction rate is 50% or more, preferably 60% or more of the total thermal decomposition reaction rate.
The thermal decomposition treatment is performed to obtain a thermal decomposition reaction rate of ~75%, and this thermal decomposition reaction rate can be adjusted by adjusting the reaction temperature, reaction pressure, and residence time.

The reaction conditions in the complete mixing reactor are a temperature of 400 to 4
50℃, reaction pressure loommt (g-5kg/cJ
G. Reaction time: 10-120 minutes, preferably 30-60 minutes
It's a minute.

Further, this complete mixing reactor is operated under reduced pressure or by supplying steam under conditions of a hydrocarbon partial pressure of 100 to 600 mmHg. The thermal decomposition reaction rate in this complete mixing reactor is 50% or less of the total thermal decomposition reaction rate, preferably 25 to 4
0%, but this thermal decomposition reaction rate can be adjusted by the reaction temperature, hydrocarbon partial pressure, and reaction time, and can be adjusted by 1 reaction time when the reaction temperature and reaction pressure are held constant. In this fully mixed reactor, liquid pitch and gaseous products including cracked light oil are produced.

The liquid pitch produced in this reactor contains mesophase, but in the case of the present invention, the proportion of this mesophase is small, usually 30% by volume or less, especially 15 to 25% by volume; Mesoface has a particle size of 20-50
Carbonization (coking) with good dispersibility in a pinch of about μm
It is difficult to do.

The decomposition heating furnace used is one equipped with an externally heated tube type reactor, and the complete mixing type reactor is usually a master type equipped with an internal stirring device. In order to keep the reactor walls clean, a wet wall method or a method using a scraper or the like is used. As these decomposition heating furnaces and complete mixing type reactors, conventionally known ones may be arbitrarily employed.

When carrying out the method of the present invention, as described above, most of the thermal decomposition reactions are completed in the decomposition heating furnace, so the reaction conditions of the decomposition heating furnace become severe, and in some cases, the decomposition heating furnace Although it is expected that coking troubles will occur in the cracking heating furnace, the occurrence of coking troubles in the cracking heating furnace can be prevented by various methods. can be prevented.

In this case, the circulating cracked heavy oil has a boiling point of 340°C.
The above are used.

The circulation ratio of the cracked heavy oil to the feedstock oil is 1
The amount is 0.1 to 0.3 parts by weight.

If this circulation ratio becomes too high, cracked gas and pitch will increase, leading to a decrease in the yield of cracked oil, which is not preferable.

Next, the method of the present invention will be explained in more detail with reference to the drawings. In the drawings, 1 is a decomposition heating furnace, 2 is a complete mixing reactor, 3 is a pitch cooler, and 4 is a fractionating column.

The feedstock oil is supplied to the cracking and heating furnace 1 through the line 5, but in this case, before being introduced into the cracking and heating furnace 1, it is passed through the fractionating column 4.
It is mixed with cracked heavy oil recycled from the bottom of the column. The feedstock oil to which this cracked heavy oil has been added undergoes thermal decomposition treatment in a cracking heating furnace 1, and the thermal decomposition product is introduced into a complete mixing reactor 2 through a line 7, where it is heated. It is further subjected to pyrolysis treatment. In this case, high-temperature steam (temperature approximately 400 to 70 ℃
00°C) is introduced to heat the liquid pitch as the contents of the reactor 2 to further thermally decompose it, promote the dissipation of volatile components in the liquid pitch from the pitch, and cause carbonization in the reactor space. Reduce hydrogen partial pressure. This reactor 2
The gaseous components containing the cracked oil produced in are introduced into the fractionating column 4 through line 10. On the other hand, the liquid pitch obtained in the reactor 2 is extracted through the line 9 and introduced into the pitch cooler 3, where the liquid pitch is cooled and the reaction is stopped.

The liquid pitch from the pinch cooler 3 is extracted through a line 11 as product pitch.

The gaseous components introduced into the fractionator 4 through line 10 are fractionated here, followed by cracked gas through line 14, cracked light oil (boiling point C5-370°C) through line 15, and line 16. Through line 17, cracked heavy oil (boiling point 370-538°C) is extracted, and through line 17, recycled cracked heavy oil (boiling point 538°C or higher) is extracted. The cracked heavy oil extracted through line 17 is circulated to be mixed with the feedstock oil.

When carrying out the present invention, various modifications are possible.1 For example, it is possible to use a plurality of fractionating columns as the fractionating column 4, and instead of feeding the raw oil directly to the cracking furnace. It is also possible to introduce the mixture of raw material oil and cracked heavy oil into the cracking and heating furnace 1 into the fractionating column 4 in advance, and obtain the raw material oil and cracked heavy oil from the bottom of the column. In addition, the cracked heavy oil in line 16 can be added to the cracked heavy oil from the bottom of the tower to be added to the feedstock oil, and furthermore, it is not necessarily necessary to circulate the cracked heavy oil to this feedstock oil. , that cycle can be omitted.

〔effect〕

Unlike the prior art, as described above, the present invention thermally decomposes petroleum-based heavy oil using a combination of a decomposition heating furnace and one complete mixing reactor, thereby continuously and continuously reacting. The objective is to obtain sufficiently lightened cracked oil and pitch suitable as a fuel with a volatile content of 30 to 45% by weight while suppressing coking troubles in the vessel. In the conventional pyrolysis treatment of petroleum-based heavy oil, when a combination of one cracking heating furnace and one complete mixing reactor is used, the membranes produced in the complete mixing reactor tend to coalesce and form carbon deposits. thing,
That is, it was easy to cause coking trouble, but in the case of the present invention, the mesophase generated in the pitch has a small particle size, is difficult to coalesce, and has good dispersibility in the pitch and is difficult to deposit carbon. It is.

The method of the present invention uses a simplified device system consisting of a combination of a decomposition heating furnace and one complete mixing reactor as a pyrolysis device, and continuously pyrolyzes feedstock oil. , which is extremely economical and has great industrial significance.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 Using the apparatus shown in the drawings, heavy petroleum oil having the properties shown in Table 1 was thermally decomposed.

That is, raw oil is supplied to the decomposition heating furnace at a flow rate of 300 kg/hr, and the outlet temperature and pressure are 490°C and 2.5k, respectively.
Thermal decomposition treatment was carried out under the conditions of g/cl G, and then the obtained thermal decomposition treatment product was transferred to a complete mixing type reactor (a stirred tank type reactor with an inner diameter of 500 mm and a height of 3000 mm) into which steam was introduced from the bottom. Supply, temperature 410°C, average residence time (reaction time) 26 minutes, hydrocarbon partial pressure 200mm 11g
Thermal decomposition treatment was carried out under the following conditions. In this case, the cracked heavy oil was not circulated with respect to the raw material oil. Table 2 shows the yield of decomposition products obtained by such two-stage thermal decomposition treatment, and Table 3 shows the properties of the obtained pitch.

Table 1 (Properties of raw oil) Table 2 Table 3 In the above thermal cracking treatment, the residual heat cracking reaction rate was 67%, and the cracking reaction rate in one cracking furnace was approximately 65% of the total cracking reaction rate. Met. In addition, although the operation was continued for 85 hours as described above, no coking phenomenon was observed, and the mesophase in the obtained pitch was small in particle size.
Good minute j during the pitch! /r 4toKJ f-,S
+ Six.

Example 2 In Example 1, the reaction time in the decomposition heating furnace and the complete mixing reactor was varied, and the residual heat decomposition reaction rate (approximately 6
The experiment was conducted in the same manner except that the ratio of thermal decomposition reaction rate in the decomposition heating furnace and the complete mixing reactor to 7%) was varied. Estimate the driveability and the properties of the pitch obtained,
The presence or absence of caulking properties was investigated. The results are shown in the table below.

Table 4 The evaluation method and evaluation criteria for pitch caulkability are as follows.

[Evaluation method of pinch caulking property]

Observe the membrane in the pitch using a polarizing microscope and evaluate the coking performance based on the single membrane particle size and coalescence status [pinch caulking performance evaluation criteria] ○: No caulking occurred △: Some caulking occurred Yes: Significant occurrence of coking Example 3 An experiment was conducted in the same manner as in Example 1, with cracked heavy oil circulating in the raw oil. In this case, as the cracked heavy oil, a tower bottom oil with a boiling point of 400° C. or higher obtained by fractionating a gaseous component obtained from a complete mixing reactor was used. In addition, the thermal decomposition reaction rates of the decomposition heating furnace and the complete mixing reactor were adjusted to obtain pitches with almost the same softening point. The experimental results are shown in the table below.

Table-5 8M N tin l m 11! : River 1 ni Nucho]
“Ruyaa Sugishi 1FJfj (!IIM 笥1)

[Brief explanation of drawings]

The drawing shows an example of a system diagram of an apparatus for carrying out the method of the present invention. 1... Decomposition heating furnace, 2... Complete mixing reactor, 3.
... Pitch cooler, 4... Fractionation tower. Applicant's agent Patent attorney Satoshi Ikeura Akisetsu amendment Written December 25, 1985 Patent application No. 264119 filed in 1985 2 Title of invention Method for thermal decomposition treatment of petroleum heavy oil 3 Amended Relationship with the patent case Patent applicant address: 1-9-12 Uchikanda, Chiyoda-ku, Tokyo
Name: Heavy Oil Countermeasures Technology Research Association Representative: Teruo Noguchi 4, Agent: 151

Claims (2)

[Claims] (1) When thermally cracking petroleum heavy oil, the heavy oil is treated using a combination of a cracking heating furnace and one complete mixing reactor, and the heavy oil is completely thermally cracked in the cracking heating furnace. Performs thermal decomposition treatment at a rate of 50% or more of the reaction rate, and produces a gaseous product containing liquid pitch suitable as a fuel with a volatile content of 30 to 45% by weight and cracked light oil in the fully mixed reactor. A method for thermally decomposing heavy petroleum oil, characterized by: (2) The method according to claim 1, wherein cracked heavy oil with a boiling point range of 340° C. or more produced from the process is circulated through the petroleum-based heavy oil.