JP2008297444A - Method for cracking 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 kind of hydrocarbon oil selected from heavy thermal cracking oil and an extract is subjected to cracking reaction at 280 to 580°C under 3.0 to 20.0 MPa in the absence of oxygen and hydrogen. In the method, the hydrocarbon oil is subjected to cracking reaction preferably for 30 sec to 60 min. <P>COPYRIGHT: (C)2009,JPO&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-mentioned object, the present inventor generates coke by decomposing heavy pyrolysis oil or extract at a specific temperature and pressure in the absence of oxygen and hydrogen. The present inventors have found that the heavy pyrolysis oil or extract can be decomposed and lightened without causing the present invention to be completed.

  That is, in the method for cracking hydrocarbon oil of the present invention, at least one hydrocarbon oil selected from heavy pyrolysis oil and extract is treated at a temperature of 280 to 580 ° C. and a pressure of 3 in the absence of oxygen and hydrogen. The decomposition reaction is performed under a condition of 0.0 to 20.0 MPa.

  In the hydrocarbon oil cracking method of the present invention, the hydrocarbon oil is preferably cracked for 30 seconds to 60 minutes.

  In the hydrocarbon oil cracking method of the present invention, light hydrocarbons generated at the initial stage of the cracking reaction are in a supercritical state under the above reaction conditions. Then, the supercritical light hydrocarbon surrounds and stabilizes the pyrolysis fragment generated in the pyrolysis reaction by the cage effect like a cage, thereby re-polymerizing the pyrolysis fragment. Suppress. Therefore, according to the hydrocarbon oil cracking method of the present invention, 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 0.2% by mass, and 0.04 to 0%. Most preferably, it is 15% by mass. Preferably the density (15 ° C.) is 0.90~1.20g / cm ^3, more preferably 0.99~1.10g / cm ^3, more 1.0~1.06g / cm ³ is most preferred. Preferably a kinematic viscosity at 50 ° C. is 3.0~10.5mm ² / s, more preferably 3.5~10.2mm ² / s, more 3.9～10.0Mm ² Most preferred is / 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 preferably has a density (15 ° C.) of 0.95 to 1.20 g / cm ³ , more preferably 0.99 to 1.10 g / cm ³ , and further 1 Most preferably, it is from 0.00 to 1.06 g / cm ³ . Preferably the kinematic viscosity at 75 ° C. is 15.0~20.0mm ² / s, more preferably 16.0~19.5mm ² / s, more 17.5～18.8Mm ² Most preferred is / s.

  In the hydrocarbon oil cracking method of the present invention, the hydrocarbon oil is supplied to the reaction phase, and the cracking reaction is performed in the absence of oxygen and hydrogen. In the decomposition reaction, the reaction temperature is in the range of 280 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 3.0 to 20.0 MPa, preferably in the range of 4.0 to 20.0 MPa, more preferably in the range of 4.0 to 18.0 MPa, and 4.0 to 16.0 MPa. The range of is particularly preferable. If the reaction temperature is too high, solid polymer (coke) is 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 is sufficiently lightened. Can not do it. On the other hand, 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 3.0 MPa, the light hydrocarbon does not enter a supercritical state.

  In the hydrocarbon oil cracking method of the present invention, the hydrocarbon oil is preferably cracked for 30 seconds to 60 minutes under the temperature and pressure. Here, the reaction time means a holding time after reaching a predetermined temperature. If the reaction time is less than 30 seconds, the raw material hydrocarbon oil cannot be sufficiently lightened. On the other hand, if the reaction time exceeds 60 minutes, the cage effect of the supercritical fluid is reduced and a large amount of coke is generated. Therefore, it is not preferable.

  The 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.

  Under the above temperature and pressure, a pyrolysis reaction and a hydrogenation reaction occur, and it is considered that light hydrocarbons are generated at the initial stage of the pyrolysis reaction. In the pyrolysis reaction, the starting hydrocarbon oil is simply pyrolyzed to lower the molecular weight, and light hydrocarbons are produced. 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. Here, since the light hydrocarbon generated in the initial stage of the thermal decomposition reaction is in a supercritical state under the above temperature and pressure, the light hydrocarbon in the supercritical state surrounds and stabilizes the thermal decomposition fragment by the cage effect. Therefore, repolymerization of the pyrolysis fragment is suppressed, and generation of coke can be prevented.

  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 cracking reaction under the above temperature and pressure, the pyrolysis fragment is stabilized by the cage effect of light hydrocarbons generated at the initial stage of the cracking reaction. Absent. 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 supercritical water or the like is used as a solvent, the critical pressure of water is as high as 22.1 MPa, so it is necessary to design a very high pressure apparatus in accordance with such a high critical pressure. Absent. On the other hand, in the present invention, light hydrocarbons generated at the initial stage of the decomposition reaction are used as a solvent in a supercritical state, and the light hydrocarbon has a low critical pressure, so that a lower pressure apparatus can be used.

  The product obtained as described above can be separated into oil, gas, and residue such as naphtha, kerosene, light oil, and heavy oil A by general atmospheric distillation and vacuum distillation. Used as desired active ingredient.

  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 (15 ° C.): 0.9457 g / cm ³ , kinematic viscosity at 50 ° C .: 18.1 mm ² / s) was prepared. This heavy pyrolysis oil was supplied to the reactor and reacted at a high temperature and high pressure of 450 ° C. and a pressure of 16.5 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 Ueda et al., Petroleum Institute Journal, 34 (1), 62 (1991); Aoyagi et al., Aromatics, vol.57, Spring, 2005, p50-56 ). Table 1 shows a comparison between the heavy pyrolysis oil before treatment and the heavy pyrolysis oil after treatment.

(Example 2)
Extracts (density (15 ° C.): 1.0117 g / cm ³ , kinematic viscosity at 75 ° C .: 18.2 mm ² / s) were prepared as samples by extraction and separation with furfural using a solvent refiner for lubricating oil. This extract was supplied to a reactor and reacted at a high temperature and high pressure of 450 ° C. and a pressure of 16.0 MPa for 10 minutes to cause decomposition reaction into gas, oil and residue. The test method was a batch method. Table 2 shows a comparison between the extract before treatment and the extract after treatment.

  From the result of Examples 1-2, while molecular weight fell, the component of carbon number 31 or more in FD-MS analysis decreased, the component of carbon number 14-30 increased, heavy pyrolysis oil and 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 (2)

  At least one hydrocarbon oil selected from heavy pyrolysis oil and extract is subjected to a decomposition reaction in the absence of oxygen and hydrogen under conditions of a temperature of 280 to 580 ° C. and a pressure of 3.0 to 20.0 MPa. A method for decomposing hydrocarbon oils.   The method for cracking hydrocarbon oil according to claim 1, wherein the hydrocarbon oil is subjected to a cracking reaction for 30 seconds to 60 minutes.