JP5378657B2 - Decomposition method of hydrocarbon oil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method where heavy thermal cracking oil and an extract which are hardly converted to light oils are cracked without generating cokes. <P>SOLUTION: In the method for cracking hydrocarbon oil, at least one hydrocarbon oil selected from heavy thermal cracking oil and an extract, and light hydrocarbon are uniformly mixed so that the molar ratio of the hydrocarbon oil to the light hydrocarbon (the raw material hydrocarbon/the light hydrocarbon) is controlled to 0.01 to 100, and the mixture of the hydrocarbon oil and the light hydrocarbon is subjected to cracking reaction in the supercritical state of the light hydrocarbon wherein the temperature is 240 to 580&deg;C and the pressure is 1.0 to 5.0 times the critical pressure of the light hydrocarbon. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a method for decomposing hydrocarbon oils, and more particularly, to a method for decomposing heavy pyrolysis oils and extracts that are difficult to be lightened without generating coke.

  Conventionally, useful components are recovered from crude oil by subjecting the crude oil to atmospheric distillation, vacuum distillation, or the like. At this time, a large amount of residual oil components are produced. Further, the residual oil component is further pyrolyzed to recover the oil component for use. However, the yield of heavy pyrolysis oil is still high, and a large amount of coke as a polymer is generated. Here, the heavy pyrolysis oil (HFO) is an oil obtained by a reaction in which a heavy oil fraction is heated to mainly perform a radical reaction. For example, a delayed coking method or a visbreaking method is used. Or the fraction obtained by the fluid coking method etc. Since the heavy pyrolysis oil is oil that has undergone thermal decomposition once, it is very stable against the decomposition reaction, and it is difficult to make it lighter.

  On the other hand, for example, an extract (EXT) obtained by subjecting a fraction obtained by subjecting an atmospheric distillation residue of crude oil to distillation under reduced pressure in a vacuum distillation apparatus for producing a lubricating oil raw material by solvent extraction with furfural or the like is aromatic. Although it is used in heavy oil preparations, rubber compounding oils and the like because of its large amount and high solubility, it has recently been demanded that the extract be lightened and used for other purposes. However, since the extract has a large aromatic content, it is very stable against the decomposition reaction, and it is difficult to further reduce the weight. For this reason, hydrocracking that requires a large amount of hydrogen is generally used to lighten heavy oil (Non-patent Document 1).

Further, as a method for reforming heavy oil such as oil sand, a reforming method using supercritical water (Patent Document 1) and a reforming method including a heavy carbonaceous source and water (Patent Document 2) are known. It has been.
JP-A-6-270763 JP 2002-155286 A Hydrocracking of pyrolysis oil, Hung. J. Ind. Chem., Vol.17, No. 1, page 31-40, 1989

  As described above, the heavy pyrolysis oil and extract are very stable against the decomposition reaction, and it is difficult to further reduce the weight. On the other hand, coke is generated when the conditions for the decomposition reaction are made strict, for example, by raising the reaction temperature.

  Therefore, an object of the present invention is to provide a method for decomposing heavy pyrolysis oil and extract that are difficult to be lightened without generating coke.

  As a result of intensive studies to achieve the above object, the present inventor has mixed heavy pyrolysis oil or extract with light hydrocarbons at a specific molar ratio, and the resulting mixture is in a supercritical state of light hydrocarbons. It has been found that heavy pyrolysis oil or extract can be decomposed and reduced in weight without causing coke by the decomposition reaction, and the present invention has been completed.

That is, the hydrocarbon oil cracking method of the present invention comprises a molar ratio of at least one hydrocarbon oil selected from heavy pyrolysis oil and extract and light hydrocarbons to light hydrocarbons ( Raw material hydrocarbon oil / light hydrocarbon) is uniformly mixed at a ratio of 0.01 to 100, and the mixture of the hydrocarbon oil and light hydrocarbon is heated to 240 to 580 ° C. and the pressure is light hydrocarbon. A hydrocarbon oil cracking method in which a light hydrocarbon is cracked and reacted in a supercritical state of 1.0 to 5.0 times the critical pressure , wherein the light hydrocarbon is a saturated hydrocarbon having 4 to 10 carbon atoms. It is characterized by.

  In the hydrocarbon oil cracking method of the present invention, it is preferable that the mixture of the hydrocarbon oil and the light hydrocarbon is subjected to a cracking reaction in a supercritical state of the light hydrocarbon for 30 seconds to 60 minutes.

In the hydrocarbon oil cracking method of the present invention, the light hydrocarbon is a saturated hydrocarbon having 4 to 10 carbon atoms , and normal pentane, cyclopentane, normal hexane, cyclohexane, and hydrogen in these hydrocarbons is alkyl. More preferred are hydrocarbons substituted with groups, normal hexane and cyclohexane being particularly preferred.

  According to the hydrocarbon oil cracking method of the present invention, a supercritical light hydrocarbon surrounds and stabilizes a pyrolysis fragment generated by a pyrolysis reaction by a cage effect like a cage. Thus, in order to suppress repolymerization of the pyrolysis fragment, the heavy pyrolysis oil and / or the extract can be decomposed and lightened while preventing the generation of coke.

The present invention is described in detail below. The raw material hydrocarbon oil used in the present invention is heavy pyrolysis oil (HFO) and / or extract (EXT). Here, the heavy pyrolysis oil is an oil obtained by applying heat to a heavy oil fraction and mainly performing a radical reaction. For example, atmospheric distillation residue, vacuum distillation residue, tar sand , A fraction obtained by a delayed coking method, a visbreaking method or a fluid coking method using oil shale, bitumen, shale oil, natural heavy oil or the like as a raw material. The heavy pyrolysis oil used in the present invention preferably has a sulfur content of 0 to 0.3% by mass, more preferably 0.01 to 0.20% by mass, and further 0.044%. It is preferable that it is -0.15 mass%, and a density (15 degreeC) is 0.9-1.20 g / cm < ³ >, More preferably, it is 0.99-1.10 / cm < ³ >, Furthermore, 1.0-1 0.06 g / cm ³ is preferable, and the kinematic viscosity at 50 ° C. is 3.0 to 10.5 mm ² / s, more preferably 3.5 to 10.2 mm ² / s, and further 3.9 to 10 It is preferably 0.0 mm ² / s.

On the other hand, an extract generally refers to an oil that is dissolved and separated in a solvent by a solvent extraction method. In petroleum refining, an oil that is extracted and separated by, for example, furfural in a solvent refining apparatus for lubricating oil is referred to as an extract. ing. As described above, the extract has a large aromatic content and high solubility, and is therefore mainly used in heavy oil preparations, rubber compounding oils, and the like. In addition, the oil component which is not extracted with a solvent is called raffinate, and is used as lubricating base oil. The extract used in the present invention has a density (15 ° C.) of 0.95 to 1.2 g / cm ³ , more preferably 0.99 to 1.10 / cm ³ , and further 1.00 to 1.06 g / cm. preferably ³ is a kinematic viscosity at 75 ℃ 15.0~20.0mm ² / s, more preferably 16.0~19.5mm ² / s, more 17.5~18.8mm ² / It is preferable that it is s.

In addition, the light hydrocarbon in the present invention, boiling point refers to a hydrocarbon 35 ° C. or higher 180 ° C. or less, no harm be contained oxygen in the molecule, is a saturated hydrocarbon having 4 to 10 carbon atoms . Here, preferable examples of the saturated hydrocarbon having 4 to 10 carbon atoms include normal pentane, cyclopentane, normal hexane, and cyclohexane, and hydrocarbons in which hydrogen in these hydrocarbons is substituted with an alkyl group, Among these, normal hexane and cyclohexane are particularly preferable.

  In the hydrocarbon oil cracking method of the present invention, first, a hydrocarbon oil selected from the above heavy pyrolysis oil and extract and light hydrocarbons are uniformly mixed to obtain a mixture. Here, the molar ratio of hydrocarbon oil to light hydrocarbon (raw oil / light hydrocarbon) is in the range of 0.01 to 100, preferably in the range of 0.01 to 50, and in the range of 0.01 to 10. Is more preferable, and the range of 0.1 to 1 is particularly preferable. If there are too many light hydrocarbons compared to hydrocarbon oil, the throughput of hydrocarbon oil will decrease and productivity will decrease, while if there are too few light hydrocarbons compared to hydrocarbon oil, This is not preferable because the cage effect is reduced and a large amount of coke is generated.

  In the hydrocarbon oil cracking method of the present invention, next, the mixture of the hydrocarbon oil and the light hydrocarbon is supplied to the reaction phase, and the cracking reaction is performed in the light hydrocarbon in a supercritical state. In the decomposition reaction, the reaction temperature is in the range of 240 to 580 ° C, preferably in the range of 330 to 550 ° C, more preferably in the range of 380 to 500 ° C, and particularly preferably in the range of 430 to 480 ° C. The reaction pressure is in the range of 1.0 to 5.0 times the critical pressure of the light hydrocarbon used, preferably in the range of 1.0 to 4.0 times, and 1.0 to 3.0 times. A range is more preferred. If the reaction temperature is too high, solid polymer (coke) will be generated even in the cracking reaction in supercritical light hydrocarbons. On the other hand, if the reaction temperature is too low, the raw hydrocarbon oil will be sufficiently lightened. Can not do it. In addition, if the reaction pressure is too high, it is necessary to design a high-pressure apparatus, which is not economical. On the other hand, if the reaction pressure is less than the critical pressure of the light hydrocarbon used, the light hydrocarbon will not be in a supercritical state. .

  In the hydrocarbon oil cracking method of the present invention, the mixture of the hydrocarbon oil and the light hydrocarbon is preferably subjected to a cracking reaction for 30 seconds to 60 minutes in the supercritical state of the light hydrocarbon. If the reaction time is less than 30 seconds, the starting hydrocarbon oil cannot be sufficiently lightened. On the other hand, if the reaction time exceeds 60 minutes, over-decomposition and coking occur, and the target hydrocarbon oil This is not preferable because the yield is greatly reduced.

  The hydrocarbon oil / light hydrocarbon molar ratio, temperature condition, pressure condition, and reaction time are appropriately selected depending on the ratio of the high value-added component contained in the product that is the object of recovery. In addition, the reaction may be performed in a batch system or a flow system.

  In the supercritical state of the light hydrocarbon, a thermal decomposition reaction and a hydrogenation reaction occur. That is, in the supercritical state of light hydrocarbons, non-covalent bonds such as hydrogen bonds in the raw hydrocarbon oil are dissociated and expanded, thereby making it easier for the decomposition reaction to proceed. In the pyrolysis reaction, the starting hydrocarbon oil is simply pyrolyzed to lower the molecular weight. On the other hand, in the hydrogenation reaction, H is added to the pyrolysis fragments (radicals) generated during the pyrolysis reaction of the raw hydrocarbon oil, thereby stabilizing the pyrolysis species. This is because the pyrolysis fragment is surrounded by the supercritical light hydrocarbon and stabilized by the cage effect of the light hydrocarbon in the supercritical state. As a result, repolymerization of the pyrolysis fragment is suppressed, so that generation of coke can be prevented. Thus, in a light hydrocarbon in a supercritical state, a thermal decomposition reaction and a hydrogenation reaction are performed in combination, and the decomposition reaction proceeds without generating coke.

  In the existing technology (for example, gas phase pyrolysis, etc.), when the decomposition temperature is raised and converted in a high temperature state, the pyrolysis fragments are recombined (repolymerized), but the amount of coke generated increases. In the decomposition reaction in light hydrocarbons in the supercritical state, the pyrolysis fragment is stabilized by the cage effect, so that the amount of coke produced does not increase even when converted at a high temperature. However, in the decomposition reaction in light hydrocarbons in a supercritical state, a solid polymer (coke) is generated at a reaction temperature exceeding 580 ° C. Therefore, in the present invention, the decomposition reaction is performed at 580 ° C. or lower.

  In addition, when the solvent to be in the supercritical state is water, the critical pressure of water is as high as 22.1 MPa. Therefore, it is necessary to design a very high pressure apparatus according to the high critical pressure, which is not economical. On the other hand, when the solvent to be in the supercritical state is light hydrocarbon, since the critical pressure is low, a lower pressure apparatus can be used. From the viewpoint of the economics of the apparatus, it is preferable to select a light hydrocarbon having a critical pressure of 4.0 to 10.0 MPa.

  The product obtained as described above can be separated into oils such as naphtha, kerosene, light oil, A heavy oil, gas, and residue by general atmospheric distillation or vacuum distillation. The oil and gas are used as desired active ingredients in desired applications, and light hydrocarbons used as a solvent can be recovered from the oil and reused as a supercritical fluid.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples.

Example 1
As a sample, a heavy pyrolysis oil obtained by pyrolyzing a petroleum vacuum distillation residue (sulfur content: 2.5 mass%, density: 0.9457 g / cm ³ , kinematic viscosity at 50 ° C .: 18.1 mm ² / S) was prepared. This sample and normal hexane were mixed at a sample / normal hexane molar ratio of 0.18 to prepare a mixture. Next, the mixture was supplied to a reactor and reacted in a supercritical state of normal hexane at a temperature of 450 ° C. and a pressure of 4.2 MPa for 10 minutes to cause decomposition reaction into gas, oil and residue. The test method was a batch method. Next, the molecular weight of the product, the carbon number distribution in FD-MS analysis, the content of components having 31 or more carbon atoms, the content of components having 14 to 30 carbon atoms, and U values of 2 and − The content of components belonging to the fraction of 6 and having 31 or more carbon atoms, the content of components belonging to the fraction of U values of 2 and -6 in the U value classification and having 14 to 30 carbon atoms, and the amount of coke produced were measured.

The molecular weight of the hydrocarbon oil is defined as being equal to the average molecular weight (Mn) measured by FD-MS. Also, the carbon number distribution is defined as one calculated from the carbon number measured by FD-MS. Moreover, the U value of the product is represented by the following formula:
MW = 14n + U
[Wherein MW is a molecular weight, n is a natural number, U is 2, 0, −2, −4, −6, −8, or −10] According to the above, the products are classified into 7 types (see Ueda et al., Journal of Petroleum Institute, 34 (1), 62 (1991); Aoyagi et al., Aromatics, vol.57, Spring issue, 2005, p50-56. ). Table 1 shows a comparison between the heavy pyrolysis oil before treatment and the heavy pyrolysis oil after treatment.

(Example 2)
In the same manner as in Example 1, except that cyclohexane was used instead of normal hexane, the reaction temperature was 470 ° C., the reaction pressure was 14.4 MPa, and the reaction time was 10 minutes. The decomposition reaction was performed in a supercritical state. The results are shown in Table 2.

(Example 3)
As a sample, an extract (density: 1.0117 g / cm ³ , kinematic viscosity at 75 ° C .: 18.2 mm ² / s) was prepared by extraction and separation with furfural using a solvent refiner for lubricating oil. This sample and cyclohexane were mixed at a sample / cyclohexane molar ratio of 0.18 to prepare a mixture. Next, the mixture was supplied to a reactor and reacted in a supercritical state of cyclohexane at a temperature of 470 ° C. and a pressure of 13.9 MPa for 10 minutes to cause decomposition reaction into gas, oil and residue. The test method was a batch method. Next, in the carbon number distribution, the content of components having 31 or more carbon atoms, the content of components having 14 to 30 carbon atoms, and the amount of coke produced were measured. Molecular weight of the product, belonging to the fraction of U value 2 and -6 in the U value classification in the FD-MS analysis and the content of components having 31 or more carbon atoms, belonging to the fraction of U value 2 and -6 in the U value classification and The content of components having 14 to 30 carbon atoms and the amount of coke produced were measured. Table 3 shows a comparison between the extract before treatment and the extract after treatment.

  From the results of Examples 1 to 3, the molecular weight decreased, the component having 31 or more carbon atoms in the FD-MS analysis decreased, and the component having 14 to 30 carbon atoms increased. It can be seen that the extract is lighter. In addition, since alkane belongs to the fraction of U value 2, and alkylbenzene belongs to the fraction of U value -6, it is considered that these alkane and alkylbenzene were decomposed.

Claims (4)

A molar ratio of the hydrocarbon oil to the light hydrocarbon (raw hydrocarbon oil / light hydrocarbon) of at least one hydrocarbon oil selected from heavy pyrolysis oil and extract and light hydrocarbon is 0.01. Mix evenly at a rate of ~ 100,
The mixture of the hydrocarbon oil and the light hydrocarbon is decomposed in a supercritical state of the light hydrocarbon at a temperature of 240 to 580 ° C. and a pressure of 1.0 to 5.0 times the critical pressure of the light hydrocarbon. A method for cracking hydrocarbon oil, comprising:
The method for cracking hydrocarbon oil, wherein the light hydrocarbon is a saturated hydrocarbon having 4 to 10 carbon atoms .   The method for cracking a hydrocarbon oil according to claim 1, wherein the mixture of the hydrocarbon oil and the light hydrocarbon is subjected to a cracking reaction in a supercritical state of the light hydrocarbon for 30 seconds to 60 minutes. Wherein said light hydrocarbon is characterized normal pentane, cyclopentane, hexane normal, cyclohexane and the hydrogen in these hydrocarbon is at least one selected from the group consisting of hydrocarbon substituted with an alkyl group Item 4. The hydrocarbon oil decomposition method according to Item 1 . The method for decomposing hydrocarbon oil according to claim 3 , wherein the light hydrocarbon is normal hexane or cyclohexane.