Method for producing monocyclic aromatic hydrocarbons

Abstract

A method of producing monocyclic aromatic hydrocarbons includes bringing a light feedstock oil having a 10 vol % distillation temperature of 140° C. to 205° C. and a 90 vol % distillation temperature of 300° C. or lower, which has been prepared from a feedstock oil having a 10 vol % distillation temperature of 140° C. or higher and a 90 vol % distillation temperature of 380° C. or lower, into contact with a catalyst for monocyclic aromatic hydrocarbon production containing a crystalline aluminosilicate, in which a content ratio of monocyclic naphthenobenzenes in the light feedstock oil is adjusted by distillation of the feedstock oil such that the content ratio of monocyclic naphthenobenzenes in the light feedstock oil is higher than a content ratio of monocyclic naphthenobenzenes in the feedstock oil.

Claims

1. A method of producing monocyclic aromatic hydrocarbons comprising: distilling a feedstock oil having a 10 vol % distillation temperature of 140° C. or higher and a 90 vol % distillation temperature of 380° C. or lower to obtain a light feedstock oil having a 10 vol % distillation temperature of 140° C. to 205° C. and a 90 vol % distillation temperature of 300° C. or lower, wherein a content ratio of monocyclic naphthenobenzenes in the light feedstock oil is higher than a content ratio of monocyclic naphthenobenzenes in the feedstock, contacting the light feedstock oil with a catalyst for monocyclic aromatic hydrocarbon production containing phosphorus and/or boron and a crystalline aluminosilicate in the absence of hydrogen gas to obtain monocyclic aromatic hydrocarbons, wherein a content of the phosphorus and/or boron in the catalyst is 0.1 mass % to 10 mass % based on the total mass of the catalyst, and wherein the contacting of the light feedstock oil with the catalyst is performed at a reaction pressure of 1.5 MPaG or less.

2. The method of producing monocyclic aromatic hydrocarbons according to claim 1, wherein the content ratio of monocyclic naphthenobenzenes in the light feedstock oil is 10 mass % to 70 mass %.

3. The method of producing monocyclic aromatic hydrocarbons according to claim 2, wherein the feedstock oil contains a light cycle oil which is produced by a fluid catalytic cracking apparatus.

4. The method of producing monocyclic aromatic hydrocarbons according to claim 1, wherein the content ratio of monocyclic naphthenobenzenes in the light feedstock oil is 12 mass % to 70 mass %.

5. The method of producing monocyclic aromatic hydrocarbons according to claim 4, wherein the feedstock oil contains a light cycle oil which is produced by a fluid catalytic cracking apparatus.

6. The method of producing monocyclic aromatic hydrocarbons according to claim 1, wherein the feedstock oil contains a light cycle oil which is produced by a fluid catalytic cracking apparatus.

7. The method of producing monocyclic aromatic hydrocarbons according to claim 1, wherein the contact time between the light feedstock oil and the catalyst is 1 second to 300 seconds.

Description

EXAMPLES

(1) Hereinafter, the invention will be more specifically described based on Examples and Comparative Examples, but the invention is not limited by these Examples.

(2) [Preparation Example of Catalyst]

(3) Preparation of Catalyst Containing Crystalline Aluminosilicate:

(4) A solution (A) composed of 1706.1 g of sodium silicate (J sodium silicate No. 3, SiO.sub.2: 28 mass % to 30 mass %, Na: 9 mass % to 10 mass %, balance water, manufactured by Nippon Chemical Industrial Co., Ltd.) and 2227.5 g of water, and a solution (B-1) composed of 64.2 g of Al.sub.2(SO.sub.4).sub.3.14 to 18H.sub.2O (reagent grade, manufactured by Wako Pure Chemical Industries, Ltd.), 369.2 g of tetrapropylammonium bromide, 152.1 g of H.sub.2SO.sub.4 (97 mass %), 326.6 g of NaCl and 2975.7 g of water were each prepared.

(5) Next, while the solution (A) was stirred at room temperature, the solution (B-1) was slowly added to the solution (A). The mixture thus obtained was vigorously stirred for 15 minutes in a mixer, and the gel was crushed to obtain a homogenously fine emulsified-state.

(6) Subsequently, this mixture was placed in an autoclave made of stainless steel, and a crystallization operation was carried out under self-pressure under the conditions including a temperature of 165° C., a time of 72 hours, and a stirring speed of 100 rpm. After completion of the crystallization operation, the product was filtered to collect a solid product, and washing and filtration was repeated 5 times by using about 5 liters of deionized water. The solid obtained by filtration was dried at 120° C., and the solid was calcined at 550° C. for 3 hours under a stream of air.

(7) It was confirmed by an X-ray diffraction analysis that the calcination product thus obtained had an MFI structure. Further, the SiO.sub.2/Al.sub.2O.sub.3 ratio (molar ratio) obtained by a MASNMR analysis was 64.8. Furthermore, the content of the aluminum element contained in the lattice structure calculated from these results was 1.32 mass %.

(8) Subsequently, a 30 mass % aqueous solution of ammonium nitrate was added at a ratio of 5 mL per 1 g of the calcination product thus obtained, and the mixture was heated and stirred at 100° C. for 2 hours, subsequently filtered and washed with water. This operation was repeated 4 times, and then the mixture was dried at 120° C. for 3 hours. Thus, an ammonium type crystalline aluminosilicate was obtained. Thereafter, calcination was carried out for 3 hours at 780° C., and thus a proton type crystalline aluminosilicate was obtained.

(9) Subsequently, 120 g of the proton type crystalline aluminosilicate thus obtained was impregnated with 120 g of an aqueous solution of gallium nitrate such that 0.4 mass % (a value calculated with respect to 100 mass % of the total mass of the crystalline aluminosilicate) of gallium would be supported, and the resultant was dried at 120° C. Thereafter, the product was calcined at 780° C. for 3 hours under an air stream, and thus a gallium-supported crystalline aluminosilicate was obtained.

(10) Subsequently, 30 g of the gallium-supported crystalline aluminosilicate thus obtained was impregnated with 30 g of an aqueous solution of diammonium hydrogen phosphate such that 0.7 mass % of phosphorus (a value calculated with respect to 100 mass % of the total mass of the crystalline aluminosilicate) would be supported, and the resultant was dried at 120° C. Thereafter, the product was calcined at 780° C. for 3 hours under an air stream, and thus a catalyst containing a crystalline aluminosilicate, gallium and phosphorus was obtained.

(11) The crystalline aluminosilicate containing gallium and phosphorus thus obtained was tabletted by applying a pressure of 39.2 MPa (400 kgf), and the catalyst was coarsely crushed and adjusted to a 20 to 28 mesh size. Thus, a granular catalyst (hereinafter, also referred to as “granulated catalyst”) was obtained.

Example 1

Example 1 Using Lightened Feedstock Oil

(12) (Preparation of Feedstock Oil)

(13) A light cycle oil (LCO1) produced by a fluid catalytic cracking apparatus was prepared as a feedstock oil. The composition of the LCO1 was as follows: a total amount (saturated fraction+olefin fraction) of saturated fraction (total amount of paraffin fraction and naphthene fraction) and unsaturated fraction (olefin fraction): 22 mass, bicyclic naphthene fraction: 2 mass %, monocyclic naphthenobenzene fraction: 9 mass %, monocyclic aromatic fraction: 30 mass %, bicyclic aromatic fraction: 39 mass %, and tricyclic or higher-cyclic aromatic fraction: 9 mass %.

(14) With respect to of the LCO1, the 10 vol % distillation temperature was 213° C., and the 90 vol % distillation temperature was 343° C.

(15) The properties of the LCO 1 are shown in Table 1.

(16) The LCO1 was subjected to fractional distillation by distillation, thereby obtaining light LCO1 having the 90 vol % distillation temperature of 295° C. The content ratio of monocyclic naphthenobenzenes in the obtained light LCO1 was 14 mass %. The properties of the light LCO 1 are shown in Table 1.

(17) The compositions shown in Table 1 was analyzed by a method of using a two-dimensional gas chromatography apparatus (manufactured by ZOEX Corp., KT2006 GC×GC system,) and compositions of subsequent feedstock oils and light feedstock oils were analyzed in the same manner.

(18) (Fixed Bed Reaction Test)

(19) Using a flow type reaction apparatus of which a reactor was filled with 5.5 g of a granulated catalyst, the light LCO1 was brought into contact with the granulated catalyst to react therewith under the conditions including a reaction temperature of 540° C. and a reaction pressure of 0.3 MPaG. The contact time between the feedstock and the zeolite component contained in the granulated catalyst was set to 12 seconds.

(20) When the feedstock are allowed to react for 30 minutes, and then a composition analysis of a product by gas chromatography directly connected to the apparatus was carried out, the yield of monocyclic aromatic hydrocarbons having 6 to 8 carbon atoms was 38 mass %, and the yield of cracked gas (hydrogen, methane, ethane, ethylene, LPG) was 15 mass %. The results are shown in Table 1.

Example 2

Example 2 Using Lightened Feedstock Oil

(21) The LCO1 was subjected to fractional distillation by distillation, thereby obtaining light LCO2 having the 90 vol % distillation temperature of 271° C. The content ratio of monocyclic naphthenobenzenes in the obtained light LCO2 was 16 mass %. The properties of the light LCO2 are shown in Table 1.

(22) The reaction test was conducted in the same condition as in Example 1, except that the light LCO2 was used instead of the light LCO1. As a result, the yield of monocyclic aromatic hydrocarbons having 6 to 8 carbon atoms was 43 mass %, the yield of cracked gas was 13 mass %. The results are shown in Table 1.

Example 3

Example 3 Using Lightened Feedstock Oil

(23) The LCO1 was subjected to fractional distillation by distillation, thereby obtaining light LCO3 having the 90 vol % distillation temperature of 244° C. The content ratio of monocyclic naphthenobenzenes in the obtained light LCO3 was 18 mass %.

(24) The reaction test was conducted in the same condition as in Example 1, except that the light LCO3 was used instead of the light LCO1. As a result, the yield of monocyclic aromatic hydrocarbons having 6 to 8 carbon atoms was 45 mass %, the yield of cracked gas was 13 mass %. The results are shown in Table 1.

Comparative Example 1

(25) Example Using Feedstock Oil with Content Ratio of Monocyclic Naphthenobenzenes not Adjusted:

(26) The reaction test was conducted in the same condition as in Example 1, except that the LCO1 was used instead of the light LCO1. As a result, the yield of monocyclic aromatic hydrocarbons having 6 to 8 carbon atoms was 32 mass %, the yield of cracked gas was 10 mass %. The results are shown in Table 1.

Example 4

Example 4 Using Lightened Feedstock Oil

(27) A mixed solution containing 106 g of sodium silicate (J Sodium Silicate No. 3, SiO.sub.2: 28 mass % to 30 mass %, Na: 9 mass % to 10 mass %, remainder: water, manufactured by Nippon Chemical Industrial Co., Ltd.) and pure water was added dropwise to a dilute sulfuric acid to prepare a silica sol aqueous solution (SiO.sub.2 concentration: 10.2%). Meanwhile, distilled water was added to 20.4 g of the crystalline aluminosilicate, which had been prepared in the [Preparation Example of Catalyst], containing gallium and phosphorus to prepare a zeolite slurry. The zeolite slurry was mixed with 300 g of the silica sol aqueous solution, and the resulting slurry was spray dried at 250° C., obtaining a spherically shaped catalyst. Subsequently, the catalyst was calcined for 3 hours at 600° C., obtaining a powdered catalyst (hereinafter, referred to as the “powdered catalyst”) having an average particle size of 84 μm and a bulk density of 0.74 g/cc.

(28) (Fluidized Bed Reaction Test)

(29) Using a fluidized bed reaction apparatus of which a reactor was filled with a powered catalyst (400 g), monocyclic aromatic hydrocarbons were produced under the conditions including a reaction temperature of 540° C., a reaction pressure of 0.3 MPaG, a contact time between the light LCO 1 and the zeolite component contained in the powered catalyst of 12 seconds. As a result, an amount of monocyclic aromatic hydrocarbons having 6 to 8 carbon atoms produced was 35 mass %, and an amount of cracked gas produced was 14 mass %. The results are shown in Table 1.

(30) TABLE-US-00001 TABLE 1 Example Example Example Example Comparative 1 2 3 4 Example 1 Analysis Light Light Light Light method LCO 1 LCO 2 LCO 3 LCO 1 LCO 1 Density at 15° C. (g/cm.sup.3) JIS K 2249 0.915 0.908 0.897 0.915 0.933 Dynamic viscosity at 30° C. (mm.sup.2/s) JIS K 2283 2.16 1.86 140 2.16 3.01 Distillation initial boiling point (° C.) JIS K 2254 160 160 160 160 160 properties 10 vol % distillation temperature (° C.) 201 199 175 201 213 50 vol % distillation temperature (° C.) 246 237 221 246 262 90 vol % distillation temperature (° C.) 295 271 244 295 343 end point (° C.) 310 283 251 310 373 Composition Saturated fraction + unsaturated Gas 18 16 14 18 22 analysis fraction (mass %) chromato- graphic Bicyclic method 1 1 1 1 2 naphthene fraction (mass %) Monocyclic aromatic fraction 42 51 64 42 30 (mass %) Monocyclic 14 16 18 14 9 naphthene fraction (mass %) Bicyclic aromatic fraction (mass %) 40 33 21 40 39 Tricyclic or higher-cyclic aromatic 10 0 0 0 9 fraction (mass %) Granulated Granulated Granulated Powdered Granulated Catalyst Catalyst Catalyst Catalyst Catalyst Catalyst yield Monocyclic aromatic Gas 38 43 45 35 32 hydrocarbon having 6 to 8 chromato- carbon atoms (mass %) graphic Cracked gas (mass %) method 15 13 13 14 10

(31) From the results shown in Table 1, it was confirmed that monocyclic aromatic hydrocarbons having 6 to 8 carbon atoms could be efficiently produced in Examples 1 to 4 in which the content ratio of monocyclic naphthenobenzenes in the feedstock had been adjusted to 10 mass % or higher by distillation of LCO1 to lighten, in comparison with Comparative Example 1 in which LCO1 (the content ratio of monocyclic naphthenobenzenes was 9 mass %) of which the content ratio of monocyclic naphthenobenzenes had not been adjusted, was used.

INDUSTRIAL APPLICABILITY

(32) The method of producing monocyclic aromatic hydrocarbons according to the present invention is useful for production of monocyclic aromatic hydrocarbons which can be used as high-octane gasoline base stocks or petrochemical feedstocks and offer high added value.