JP5196396B2 - Method for pyrolysis of heavy oil - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a method for pyrolyzing heavy oil by-produced from an olefin production process such as ethylene cracker. Specifically, the heavy oil by-produced from a process for producing olefins by pyrolyzing middle distillate. The present invention relates to a heavy oil pyrolysis method in which oil is pyrolyzed to produce gasoline, kerosene, light oil, and the like. Moreover, this invention relates to the pyrolysis process oil obtained by this method.

As a method of thermal differentiation of hydrocarbons to produce olefins, aromatic hydrocarbons, and petrochemicals, in the presence of steam, hydrocarbons are burned and heavy hydrocarbons are supplied into a high-temperature gas containing steam. Methods for thermal decomposition are known (Patent Documents 1 to 3).
On the other hand, heavy oil produced as a by-product in the production of ethylene by pyrolysis of petroleum fractions has less sulfur, nitrogen, and heavy metal content compared to coal dry distillation tar and bottom oil from catalytic cracking of petroleum fractions. Heavy oil (bottom oil or ethylene heavy end) distilled from olefin production equipment (ethylene crackers, etc.) is a private fuel, although it has characteristics and is suitable as a raw material for various carbon materials. It stayed in use as.

The raw material of olefin production equipment is mainly naphtha, but it is also considered to use heavier kerosene and light oil as raw materials for diversification of raw materials. When the raw material of the olefin production apparatus becomes heavier, the bottom oil distillate also increases. Therefore, the efficiency of the use as a private fuel oil alone is poor, and a new utilization method is required.
As a method of treating heavy oil by-produced when producing ethylene by thermal decomposition of petroleum fractions, a method of treating in a hydrogen atmosphere in the presence of a solid acid catalyst is also known (Patent Document 4, 5).
Japanese Examined Patent Publication No. 3-29112 Japanese Examined Patent Publication No. 4-16512 Japanese Patent Publication No. 4-21717 Japanese Patent Publication No. 4-30436 Japanese Patent Publication No. 4-30437

  It is an object of the present invention to provide a method for thermally decomposing heavy oil such as ethylene bottom oil that has only been used as a private fuel oil, and in particular, more added value from heavy oil such as ethylene bottom oil. It is an object of the present invention to provide a method for thermally decomposing heavy oil for producing middle distillates such as gasoline, kerosene and light oil such as high fuel oil for automobiles and fuel oil for heating.

  The inventors of the present invention have developed a middle distillate having a low sulfur content by thermally decomposing heavy oil by-produced from a process for producing olefins, which is a petrochemical raw material production apparatus that has only been used as a private fuel oil. The present invention has been conceived from the knowledge that can be obtained.

That is, this invention is the thermal decomposition method of the hydrocarbon oil as follows, and the thermal decomposition process oil obtained by this method.
(1) Heavy oil obtained by pyrolyzing heavy oil produced as a by-product from the process of producing olefins by pyrolyzing middle distillate in petroleum refining at a temperature of 400 to 600 ° C. and a pressure of 0.01 to 1.00 MPa. Thermal decomposition method.
(2) Heavy oil has an aromatic content of 85 to 99% by weight, a 5% distillation temperature of 120 to 230 ° C, and a 95% distillation temperature of 550 to 700 ° C. Thermal oil pyrolysis method.
(3) The 5% distillation temperature obtained by the method described in (1) or (2) above is 80 to 200 ° C, the 95% distillation temperature is 290 to 520 ° C, and the aromatic content is 65 to 99 volumes. % Pyrolysis oil.

  Conventionally, heavy oil produced as a by-product from the process of producing olefins has only been consumed as fuel oil, particularly as private fuel oil. However, according to the present invention, high-value-added gasoline, kerosene, light oil, etc. It becomes possible to convert to a middle distillate, and there is an extraordinary effect that it can be effectively used as a fuel oil for automobiles, a fuel oil for heating, or a base material thereof. In addition, since the above heavy oil used as a raw material has a very low sulfur content and nitrogen content as compared with, for example, asphalt, the pyrolyzed oil obtained by pyrolyzing this also has a low sulfur content and a nitrogen content. Is low. For this reason, the obtained pyrolysis-treated oil can be obtained by simply fractionating without performing a special refining treatment, and can be used for automotive fuel oil, heating fuel oil, A substrate can be manufactured. That is, according to the present invention, low-value-added heavy oil can be converted into high-value-added fuel oil or the like relatively economically without introducing a large amount of energy.

  The present invention relates to a hydrocarbon oil obtained by pyrolyzing heavy oil by-produced from a process of producing olefins by pyrolysis of middle distillate in petroleum refining at a temperature of 400 to 600 ° C. and 0.01 to 1.00 MPa. It is a thermal decomposition method. Moreover, it is the pyrolysis process oil obtained by this method.

[Raw oil]
In the present invention, heavy oil produced as a by-product when producing an olefin such as ethylene is used as a raw material oil to be subjected to thermal decomposition. Any heavy oil produced as a by-product from the process of producing olefins by pyrolyzing middle distillates in petroleum refining is not particularly limited, and any known olefin production process can be operated under appropriate operating conditions. The heavy oil obtained in this way can be used. In the olefin production process, the target olefin content (ethylene, propylene), by-product LPG, gasoline fractions such as aromatic hydrocarbons (benzene, toluene, xylene), hydrogen, methane, etc., are obtained by thermal decomposition of hydrocarbons. Over time, heavy oil is produced as a by-product. The physical properties of heavy oil vary depending on the raw material hydrocarbons processed in the olefin production process. The heavy oil used in the present invention can be a heavy oil by-produced from an olefin production process for treating hydrocarbons such as LPG such as ethane, propane and butane, naphtha, kerosene oil, or vacuum gas oil. In petroleum refining, kerosene, light oil, and heavy oil A are usually called middle distillates and are also referred to as three intermediate products. Here, middle distillate refers to ethane, propane, butane, etc. in addition to these three intermediate products. It is a general term including LPG, naphtha, and desulfurized vacuum gas oil that is a base material of A heavy oil. Although there are olefin production processes using crude oil and residual oil as raw materials, heavy oil to be produced as a by-product in the future depends on the type of crude oil, but contains a relatively large amount of sulfur and nitrogen, so the raw material used in the present invention It is not preferable as an oil.
Examples of olefin production processes represented by ethylene crackers include the Lummus olefin process and Stone & Webster Eng. Company, Kinetics Technology International, M. W. The process of Kellogg is known (for example, “Petrochemical Process” edited by Petroleum Society, Kodansha Scientific, 25-27, 2001).

  In the present invention, as a distillation property of the raw material oil subjected to thermal decomposition, the 5% distillation temperature is preferably 120 to 230 ° C, more preferably 140 to 210 ° C, and the 95% distillation temperature is preferably 550 to 700 ° C. More preferably, it is 570-680 degreeC. If the 5% distillation temperature is lower than 120 ° C, the lower hydrocarbon fraction (gaseous hydrocarbon at normal temperature and normal pressure) increases during the pyrolysis treatment. Since the kinematic viscosity is increased, heating is required to provide fluidity, and the amount of heat consumed is increased, which is not preferable. Also, if the 95% distillation temperature is lower than 550 ° C, the amount of middle distillate of 360 ° C or less obtained when pyrolysis is reduced is not preferable, and if it is higher than 700 ° C, the residual carbon content increases. However, it is not preferable because coking is easily performed in a heating furnace in front of the coke drum.

  The aromatic content of the raw material oil affects the aromatic content in the pyrolyzed oil obtained when pyrolyzed. For example, a gasoline fraction obtained by pyrolyzing a raw material oil having a high aromatic content has a high aromatic content and a high octane number. For this reason, 85-99 weight% is preferable and, as for the aromatic content of raw material oil, Most preferably, it is 87-99 weight%.

  The lower the sulfur content and the nitrogen content, the better. However, since these cannot be removed by the olefin production process, the sulfur content in the feedstock is preferably 0.50% by weight or less, more preferably 0.20% by weight or less. . Similarly, the nitrogen content is preferably 500 ppm by weight or less, more preferably 100 ppm by weight or less.

The kinematic viscosity of the feedstock oil is preferably 5 to 1000 mm ² / s, more preferably 5 to 1000 mm ² / s, because energy must be input for heating to provide handling properties and fluidity. Is 10 to ²⁰⁰ mm ² / s.

[Pyrolysis process]
Various apparatuses, such as a flow type (continuous type), a batch type (batch type), and a semibatch type, can be used for the pyrolysis process for obtaining a pyrolysis process oil. For example, a visbreaking process, a fluid coking process, a flexi coking process, a delayed coking process, a yurika process, an HSC process, etc. (for example, “The Petroleum Society” “Oil Refinery Process”, Kodansha Scientific, pp. 197 to 205, Published in 1998). Among these, a delayed coking process can be preferably used.
The apparatus configuration and operating conditions of the delayed coking process are not particularly limited, and any known manufacturing apparatus and operating conditions can be adopted. In the delayed coking process, the feedstock oil is heated in a heating furnace and placed on a coke drum, where the pyrolysis condensation polymerization reaction is performed in a steamed state, and petroleum fractions such as higher value-added gas, cracked gasoline, kerosene gas oil, etc. This is an apparatus for producing coke at the same time as producing cracked oil. Since coke accumulates in the coke drum, the full coke drum separates from the system and cuts the deposited coke. The emptied coke drum receives the heated raw material oil again and performs a thermal decomposition condensation polymerization reaction. The delayed coking process normally includes a plurality of coke drums and repeats the above operations in order.

The heavy oil produced as a by-product from the process of producing olefins by thermal decomposition of middle distillates is a reaction temperature of 400 to 600 ° C, more preferably 450 to 550 ° C, a reaction pressure of 0.01 to 1.00 MPa, more preferably Thermal decomposition at 0.05 to 0.50 MPa. These reaction conditions can be appropriately set within this range, but are preferably set so that the yield of the pyrolysis oil is 50% by weight or more, more preferably 60% by weight or more.
When the reaction temperature for thermal decomposition is lower than 400 ° C., the yield of the pyrolysis oil decreases, which is not preferable. When the reaction temperature exceeds 600 ° C., the generation amount of cracked gas increases, which is not preferable.
A reaction pressure higher than 1.00 MPa is not preferable because the yield of the pyrolysis oil is low.

Liquid hourly space velocity may be set in consideration of the production of the size and coke device, preferably 0.01～0.50H ^-1, more preferably 0.10～0.30H ^-1 is there.
Here, the yield (wt%) of the pyrolysis oil means a value obtained by the following equation (1).
Yield of pyrolysis oil = weight of pyrolysis oil / feed amount of raw material × 100 (1)
In the formula, the weight of the pyrolysis oil is the weight of the oil recovered in the air-cooled condenser of the pyrolysis experimental apparatus, and the raw material supply amount is the heavy oil supply amount (weight) to the pyrolysis device.

[Pyrolyzed oil]
The pyrolysis oil obtained by the pyrolysis has a yield of 50% by weight or more, preferably 65% by weight or more, and the ratio of a fraction of 360 ° C. or less contained in the obtained pyrolysis oil is It is preferably 65% by weight or more, and more preferably 80% by weight or more. The fraction at 270 ° C. or lower is preferably 50% by volume or more, more preferably 60% by volume or more. The fraction at 150 to 270 ° C. is preferably 30% by volume or more, more preferably 40% by volume or more, and the fraction at 150 to 360 ° C. is preferably 60% by volume or more, more preferably 70% by volume or more. is there.

The pyrolysis oil obtained by the above pyrolysis is subjected to fractionation treatment by various methods such as fractional distillation, extraction, etc., so that various fuel oils such as gasoline, kerosene, light oil, or a preparation base for producing them. Materials etc. can be obtained.
The pyrolysis-treated oil has a distillation property of 5% distillation temperature of preferably 120 to 230 ° C, more preferably 140 to 210 ° C, and a 95% distillation temperature of preferably 290 to 520 ° C, more preferably 310. ~ 500 ° C. Of this pyrolysis-treated oil, a fraction of 360 ° C. or lower can be separated and prepared as the above-mentioned various fuel oils or their base materials using various other petroleum refining means including fractional distillation. .

That is, by fractionating the obtained pyrolysis-treated oil, for example, a fraction of 30 to 220 ° C. is used as a gasoline base, a fraction of 150 to 270 ° C. is used as a kerosene base, and 150 to 360 ° C. The following fractions can each be recovered as a light oil base.
Further, the sulfur content of the pyrolysis-treated oil is preferably 0.5 wt% or less, more preferably 0.2 wt% or less, and the nitrogen content is preferably 1000 wtppm or less, more preferably 200 wtppm. It is as follows. The sulfur content and nitrogen content in the product depend on the properties of the raw heavy oil, but the smaller the amount of impurities contained, the better.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this Example does not limit this invention.

Example 1
An ethylene bottom oil A obtained from an olefin production process (Lummus, olefin process) for producing ethylene by pyrolyzing naphtha derived from crude oil is subjected to a reaction pressure of 0.25 MPa and a reaction temperature of 500 ° C. using a pyrolysis experimental apparatus. It was pyrolyzed under steaming conditions for 12 hours. A pyrolysis oil B was obtained together with coke deposited in the apparatus. The yield of the pyrolysis oil was 71% by weight. Moreover, in the distillation property of the obtained pyrolysis-processed oil B, the fraction of 360 degrees C or less was 81 weight%. Table 1 shows properties of ethylene bottom oil A and pyrolysis oil B.
The thermal decomposition experimental apparatus is a metal reaction apparatus composed of a heating part and a cooling part. The heating part is an apparatus capable of charging a sample of about 50 g at the maximum, and the cooling part is an air-cooled condenser. The pressure was adjusted with nitrogen.

(Comparative Example 1)
A reaction pressure of 0.25 MPa was obtained using a thermal decomposition experimental apparatus in the same manner as in Example 1 except that asphalt (vacuum residue oil) C obtained by a vacuum distillation apparatus was used as a raw material oil instead of the ethylene bottom oil A. Then, pyrolysis was carried out for 12 hours under the reaction temperature of 500 ° C. The yield of the pyrolysis oil was 47% by weight. Moreover, in the distillation property of the pyrolysis-processed oil D, the fraction of 360 degrees C or less was 71 weight%. Table 2 shows the properties of asphalt C and pyrolysis oil D.

  When Example 1 and Comparative Example 1 are compared, Example 1 has a higher yield of pyrolysis-treated oil and a higher fraction of a fraction of 360 ° C. or less in the obtained pyrolysis-treated oil. Therefore, the gasoline bottom and kerosene oil can be obtained by thermally decomposing ethylene bottom oil, which has been used exclusively as an in-house fuel oil, in a delayed coker that has been processed exclusively using asphalt obtained by a conventional vacuum distillation unit. It can be seen that the fraction can be obtained with a high yield and that the production of the middle fraction can be increased.

  In Examples and Comparative Examples, the physical properties and composition of raw material oil and pyrolysis oil were measured by the following methods. Distillation properties are JIS K2254 (gas chromatography method), sulfur content is JIS K2541 (radiation excitation method, ultraviolet fluorescence method), nitrogen content is JIS K2609 (chemiluminescence method), hydrocarbon oil density is JIS K2249, and asphalt density is The kinematic viscosity of JIS K 2207, the hydrocarbon oil was measured according to JIS K 2283, and the kinematic viscosity of asphalt was measured according to JIS K 2207. The hydrocarbon component composition was measured by a TLC (Thin Layer Chromatography) method. In the TLC method, a sample was charged on a chromatorod (manufactured by Mitsubishi Chemical Yatron Co., Ltd., Chromarod-SIII), and developed with normal hexane to separate the saturate. Subsequently, the aroma content was separated by developing with toluene, and the resin content was further developed with dichloromethane / methanol (95: 5) and separated into three blocks. Thereafter, each of the three blocks was quantified with a flame ionization detector using a thin layer automatic detection device (manufactured by Mitsubishi Chemical Yatron Co., Ltd., new MK-5) to obtain a saturating component, an aromatic component, and a resin component.

Claims (2)

Aromatics by-produced from the process of producing olefins by pyrolyzing middle distillate in petroleum refining is 85 to 99 wt%, 5% distillation temperature is 120 to 230 ° C, and 95% distillation temperature is 550. Of heavy oil which is pyrolyzed so that the yield of the pyrolysis oil is 60% by weight or more at a temperature of 450 to 550 ° C. and a pressure of 0.05 to 0.50 MPa. Thermal decomposition method. A pyrolysis-treated oil obtained by the method according to claim 1, having a 5% distillation temperature of 80 to 200 ° C, a 95% distillation temperature of 290 to 520 ° C, and an aromatic content of 65 to 99% by volume.