AU2007239954B2

AU2007239954B2 - Process for hydrorefining fuel base material

Info

Publication number: AU2007239954B2
Application number: AU2007239954A
Authority: AU
Inventors: Hirofumi Konno; Hiroyuki Seki
Original assignee: Nippon Oil Corp
Current assignee: Eneos Corp
Priority date: 2006-03-30
Filing date: 2007-03-20
Publication date: 2011-09-29
Anticipated expiration: 2027-03-20
Also published as: AU2007239954A1; MY146894A; CN104987881A; RU2008143027A; WO2007119455A1; JP2007269885A; JP4834438B2; RU2429278C2; CN101410486A

Abstract

Disclosed is a process for hydrorefining a fuel base material wherein a fuel base material containing an oxygen-containing compound, an olefin and a normal paraffin is brought into contact with a hydrorefining catalyst, which is composed of a carrier containing silica-zirconia and a group VIII metal of the periodic table supported by the carrier, in the presence of hydrogen.

Description

FP07-0094-00 SPECIFICATION PROCESS FOR HYDROREFINING FUEL BASE MATERIAL TECHNICAL FIELD [0001] The present invention relates to a hydrotreating method in 5 which a fuel basestock is catalyzed by a hydrotreating catalyst in the presence of hydrogen. BACKGROUND ART [0002] Based on the idea of lessening the environmental burden, there has been demand in recent years for an environmentally-friendly, 10 clean liquid fuel that has a low sulfur content and a low aromatic hydrocarbon content. Therefore, the Fischer-Tropsch (FT) synthesis, which uses carbon monoxide and hydrogen as starting materials, has been under investigation in the petroleum industry as a method for producing clean fuels. The FT synthesis can produce a sulfur-free, 15 paraffin-rich liquid fuel basestock, and expectations for this method are quite high as a consequence. [0003] However, the fuel basestock produced by the FT synthesis contains oxygen-containing compounds and olefins and as a consequence is not necessarily suitable for direct use as a fuel, such as 20 gasoline or diesel. As a result, the oxygen-containing compounds in this fuel basestock must be eliminated and the olefins must be converted to paraffins by hydrogenation in order to effectively use this fuel basestock as a fuel. [0004] In addition, the paraffins in the fuel basestock obtained by 25 FT synthesis has a high normal-paraffin content, making this fuel basestock unsuitable for direct use as a fuel. More specifically, this fuel 1 C:\NRPonbl\DCC\WAM\385623_L.DOC-509/20= I -2 basestock has an unsatisfactory octane number for use as automotive gasoline and has an unsatisfactory low-temperature fluidity for use as diesel. A hydrotreating technology that converts the normal-paraffins in this fuel basestock to isoparaffins is therefore critical to the goals of raising the octane number and improving the low 5 temperature fluidity of the fuel basestock obtained by FT synthesis. [0005] Catalysts used for the hydroisomerization of hexane (refer, for example, to Patent Reference 1) are known as catalysts for use in this hydrotreating technology. In addition, a catalyst of palladium supported on a carrier obtained from amorphous silica-alumina having a prescribed pore volume has been disclosed 10 in Patent Reference 2 as a hydrotreating catalyst. Patent Reference 1: United States Patent No. 4,637,992 Patent Reference 2: EP 587,246 A DISCLOSURE OF THE INVENTION PROBLEM TO BE SOLVED BY THE INVENTION 15 [0006] It has heretofore been possible to achieve a satisfactory olefin hydrogenation and a satisfactory oxygen-containing compound elimination by the hydrotreating of a feed comprising a fuel basestock containing oxygen-containing compounds, olefins, and normal-paraffins. However, a hydrotreating method that, in addition to being able to eliminate the oxygen-containing compounds and carry 20 out olefin hydrogenation, is able to also satisfactorily convert normal-paraffins to isoparaffins, remains unknown. [0007] Pursuing in consideration of the circumstances described above, the present invention seeks to provide a method for hydrotreating a fuel basestock that, in addition to being able to eliminate the oxygen-containing compounds and carry 25 out olefin hydrogenation, is able to also satisfactorily convert normal-paraffins to isoparaffins.

C.WRhfttblDCC\WAM3856203I.DOC-509/20tI -3 MEANS FOR SOLVING THE PROBLEM [0008] In a first aspect, the present invention provides a method for hydrotreating a fuel basestock, wherein a fuel basestock containing oxygen containing compounds, olefins, and normal-paraffins is catalysed in the presence of 5 hydrogen by a hydrotreating catalyst comprising a carrier containing silica-zirconia and an active metal from group VIII of the Periodic Table supported on this carrier. [0009] This method for hydrotreating a fuel basestock can provide a satisfactory elimination of oxygen-containing compounds and a satisfactory hydrogenation of olefins and at the same time is able to provide a satisfactory conversion of normal 10 paraffins to isoparaffins. As a result, the method of the present invention for hydrotreating fuel basestocks can produce an isoparaffin-rich fuel basestock in high yields and as a consequence has excellent economics. [0010] The hydrotreating catalyst in the hydrotreating method of the present invention preferably contains palladium and/or platinum as the active meta' cited 15 above. The use of such a hydrotreating catalyst enables the conversion of normal paraffins to isoparaffins to be carried out at with even better efficiency and can also provide a better inhibition of catalyst deterioration. [0011] The hydrotreating catalyst in the hydrotreating method of the p-esent invention preferably additionally contains phosphorus. This makes possible an 20 additional boost in the efficiency with which normal-paraffins is converted to isoparaffins. [0012] The fuel basestock in the hydrotreating method of the present invention preferably contains a component produced by the FT reaction. The effects of the hydrotreating method of the present invention, i.e., oxygen-containing compound 25 elimination, olefin hydrogenation, and normal-paraffin-to-isoparaffin conversion, are brought out even more efficiently and with greater certainty when a fuel basestock containing such a component is used as the feedstock for the C:NRPonbnDCWAMU856203.DOC-5/9/201 -4 hydrotreating method of the present invention. EFFECTS OF THE INVENTION [0013] The present invention seeks to provide a method for hydrotreating ,a fuel basestock that, in addition to being able to eliminate oxygen-containing compounds 5 and carry out olefin hydrogenation, is able to go further and achieve a thorough conversion of normal-paraffins to isoparaffins. BEST MODE FOR CARRYING OUT THE INVENTION [0014] Suitable embodiments of the present invention are described in detail in the following. 10 [0015] The method of the present invention for hydrotreating a fuel basestock is a method in which a fuel basestock containing oxygen-containing compounds, olefins, and normal-paraffins is catalysed in the presence of hydrogen by a hydrotreating catalyst comprising a carrier containing silica-zirconia and a metal from group VIII of the Periodic Table supported on this carrier. 15 [0016] The fuel basestock is a fuel basestock that contains oxygen- FP07-0094-00 containing compounds, olefms, and normal-paraffms, but is not otherwise particularly limited. The fuel basestock can be exemplified by petroleum-based and synthetic gasoline feedstocks, kerosene feedstocks, gas oil feedstocks, and mixtures of two or more of the preceding. The 5 boiling point range of the feedstock is therefore not particularly limited and may be adjusted in correspondence to the desired product oil. For example, when the fuel oil is a gasoline basestock, the boiling point range is generally room temperature to 140'C; when the fuel oil is a gas oil basestock, the boiling point range is generally 140 to 360'C. 10 [0017] Although, for example, a mixture of gasoline basestock and gas oil basestock may be used as the starting fuel basestock, the separate hydrotreating of gasoline basestock and gas oil basestock is preferred. When hydrotreating is carried out on a basestock comprising a mixture of gasoline basestock and gas oil basestock, there is a tendency for a 15 portion of the gasoline basestock to be converted to a lighter gas fraction, resulting in a reduction in the yield of the gasoline basestock in the product. [0018] The oxygen-containing compounds comprise mainly C 2 -8 alcohols when the fuel basestock is a gasoline basestock; mainly C 8

-

13 20 alcohols when the fuel basestock is a kerosene basestock; and mainly

C

12

-

18 alcohols when the fuel basestock is a gas oil basestock. The fuel basestock may also contain aldehydes and ketones in addition to these alcohols. [0019] The olefins comprise mainly C 4

.

9 unsaturated aliphatic 25 hydrocarbons when the fuel basestock is a gasoline basestock. The olefins comprise mainly C 10

.

14 unsaturated aliphatic hydrocarbons when 5 FP07-0094-00 the fuel basestock is a kerosene basestock. The olefins comprise mainly

C

1 5-20 unsaturated aliphatic hydrocarbons when the fuel basestock is a gas oil basestock. [0020] The normal-paraffms comprise mainly C 4

.

9 straight-chain 5 saturated aliphatic hydrocarbons when the fuel basestock is a gasoline basestock. The normal-paraffins comprise mainly CIo.

14 straight-chain saturated aliphatic hydrocarbons when the fuel basestock is a kerosene basestock. The normal-paraffins comprise mainly C15-20 straight-chain saturated aliphatic hydrocarbons when the fuel basestock is a gas oil 10 basestock. [0021] The proportion of each component in the starting fuel basestock is not particularly limited. However, in order to effectively bring about isomerization of the normal-paraffms to isoparaffins, the normal-paraffin content is preferably at least 30 mass%, more preferably 15 at least 50 mass%, and particularly preferably at least 70 mass%, in each case with reference to the total quantity of the fuel basestock. [0022] In order to achieve the above-described effects of the present invention more effectively, the fuel basestock in the present invention preferably contains a component produced by the FT reaction 20 and more preferably contains only a component produced by the FT reaction. [0023] The hydrotreating catalyst used in the hydrotreating method of the present invention contains silica-zirconia as its carrier and contains a metal from group VIII of the Periodic Table as the metal supported on 25 this carrier, but is not otherwise particularly limited. [0024] The silica/zirconia molar ratio in the silica-zirconia carrier 6 FP07-0094-00 is not particularly limited, but is preferably no greater than 10. The activity of the hydrotreating catalyst tends to decline when this molar ratio exceeds 10. [0025] The hydrotreating catalyst used by the present invention 5 may also additionally contain a binder for carrier molding. While this binder is not particularly limited, alumina and silica are examples of preferred binders. The shape of the carrier is not particularly limited and can be, for example, granular or cylindrical (pellet). [0026] Metal from group VIII of the Periodic Table is supported on 10 the above-described carrier as an active metal. This group VIII metal can be specifically exemplified by iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium, and platinum. Among these metals, the use is preferred of at least one metal selected from the group consisting of nickel, rhodium, palladium, iridium, and platinum as the metal supported 15 on the carrier. The use of palladium and/or platinum as the metal supported on the carrier is more preferred, and the use of a mixture of palladium and platinum is particularly preferred. This makes it possible to more effectively inhibit catalyst deterioration in those instances where a sulfur fraction is present in the starting fuel basestock. 20 [0027] The method for supporting these metals on the carrier is not particularly limited. For example, the carrier may be impregnated with an aqueous solution containing a metal as described above, followed by drying and calcination. The amount of the aforementioned metal supported in the hydrotreating catalyst is not particularly limited, but 25 generally is 0.1 to 2.0 parts by mass per 100 parts by mass of the carrier. [0028] The hydrotreating catalyst according to the present 7 FP07-0094-00 invention preferably additionally contains phosphorus, and the phosphorus is preferably added to the carrier by, for example, impregnation. This can provide an additional promotion of the isomerization from normal-paraffms to isoparaffins. The phosphorus 5 content is preferably 0.02 to 10.0 parts by mass per 100 parts by mass of the carrier. It becomes problematic for the effects associated with phosphorus addition to be adequately manifested when the phosphorus content falls below 0.02 part by mass. When the phosphorus content exceeds 10.0 parts by mass, the yield of the desired fuel basestock tends 10 to decline accompanying a lightening of the product. [0029] The hydrotreating apparatus used for the method of the present invention for hydrotreating a fuel basestock has the ability to carry out hydrotreating by effecting catalyzing the fuel basestock by the hydrotreating catalyst in the presence of hydrogen, but is not otherwise 15 particularly limited. Thus, for example, existing fixed-bed reaction apparatuses can be used. [0030] The reaction temperature during the hydrotreating is preferably 180 to 320 0 C. Isomerization from normal-paraffins to isoparaffins tends to fail to proceed satisfactorily when the reaction 20 temperature is below 180'C. It becomes difficult to prevent lightening of the product and the yield of the desired fuel basestock therefore tends to decline when the reaction temperature exceeds 320 0 C. [0031] The reaction pressure is not particularly limited, but the hydrogen partial pressure is preferably 1 to 12 MIPa and more preferably 25 is 2 to 6 MPa. Catalyst deterioration tends to proceed readily when the hydrogen partial pressure is below 1 MPa, while the reaction temperature 8 FP07-0094-00 for obtaining a desired fuel basestock tends to rise at above 12 MPa. The liquid hourly space velocity (LHSV) is not particularly limited, but fuel basestock hydrotreating can be carried out generally at 0.1 to 5.0 h~. The ratio of the total amount of hydrogen fed to the catalyst layer with 5 respect to the amount of fuel basestock feed, that is, the hydrogen/oil ratio, is not particularly limited, but is generally in the range of 100 to 850 NL/L. [0032] In the hereinabove-described method of the present invention for fuel basestock hydrotreating, the above-described 10 hydrotreating catalyst catalyze a fuel basestock that contains oxygen containing compounds, olefms, and normal-paraffms in the presence of hydrogen under the prescribed reaction conditions. The method can effectively eliminate the oxygen-containing compounds present in the fuel basestock, such as alcohols, can effectively hydrogenate the olefins, 15 and can effectively convert (isomerize) the normal-paraffms originating in the oxygen-containing compounds and the normal-paraffins originally present in the fuel basestock into isoparaffins. [0033] More specifically, the oxygen-containing compounds, such as alcohols, that are present in the fuel basestock are eliminated by 20 conversion to hydrocarbon. In addition, both the olefms originally present in the fuel basestock and the olefins converted from, for example, alkenols in the fuel basestock are converted to paraffins by hydrogenation. With regard to the paraffins converted from, for example, alcohols, the normal-paraffms originating in, for example, normal 25 alcohols, is converted to isoparaffins along with the normal-paraffins originally present in the fuel basestock. The present invention can inhibit 9 FP07-0094-00 lightening of the fuel basestock in this hydrotreating process. Therefore, the present invention can simultaneously achieve a satisfactory elimination of the oxygen-containing compounds present in the fuel basestock, a satisfactory hydrogenation of the olefms, and a satisfactory 5 conversion of normal-paraffin to isoparaffm, while also maintaining the fuel basestock yield. [0034] While preferred embodiments of the present invention have been described in the preceding, the present invention is not limited to these embodiments. 10 EXAMPLES [0035] The present invention is described in additional detail in the following examples, but the present invention is not limited to these examples. [0036] [Catalyst preparation] 15 (Catalyst 1) Silica-zirconia (silica/zirconia molar ratio : 0.7) and alumina binder were thoroughly mixed and the resulting mixture was molded into cylinders having a length of about 3 mm and a diameter of 1.6 mm (silica-zirconia/alumina binder = 70/30 (mass ratio)). These moldings 20 were calcined for 1 hour at 500'C in air to yield the carrier. This carrier was impregnated with an aqueous nitric acid solution of chloroplatinic acid so as to support 0.6 part by mass platinum per 100 parts by mass of the carrier. This was dried for 3 hours at 120'C and then calcined for 1 hour at 500'C in the air to yield a catalyst 1. 25 [0037] (Catalyst 2) A catalyst 2 was obtained operating as for the preparation of catalyst 10 FP07-0094-00 1, with the exception that prior to supporting the platinum on the carrier, the carrier was impregnated with an aqueous solution of phosphoric acid so as to support 0.2 part by mass phosphorus per 100 parts by mass of the carrier. 5 [0038] (Catalyst 3) A catalyst 3 was obtained operating as in Example 1, except that, rather than supporting 0.6 part by mass platinum per 100 parts by mass of the carrier by impregnation with an aqueous nitric acid solution of chloroplatinic acid, 0.5 part by mass platinum and 0.1 part by mass 10 palladium were supported per 100 parts by mass of the carrier by impregnation with an aqueous nitric acid solution of chloroplatinic acid and palladium chloride. [0039] (Catalyst 4) A catalyst 4 was obtained operating as for the preparation of catalyst 15 1, but using silica-alumina (14 mass% alumina) in place of the silica zirconia (silica/zirconia molar ratio : 0.7). [0040] (Catalyst 5) A catalyst 5 was obtained operating as for the preparation of catalyst 1, but using alumina-boria (84 mass% alumina) in place of the silica 20 zirconia (silica/zirconia molar ratio : 0.7). [0041] (Catalyst 6) A carrier comprising spherical active carbon with a particle size of about 3 mm was impregnated with an aqueous nitric acid solution of chloroplatinic acid so as to support 0.6 part by mass platinum per 100 25 parts by mass of the carrier. This was dried for 3 hours at 120'C and then calcined for 1 hour at 500'C in the air to give a catalyst 6. 11 FP07-0094-00 [0042] [Hydrotreating] (Example 1) A fixed-bed flow-type reactor was filled with Catalyst 1 (100 mL). This catalyst 1 was then activated by carrying out a reduction treatment 5 thereon for 3 hours at 340*C in a hydrogen atmosphere. [0043] A fuel basestock having a boiling point range of 140 to 360'C and obtained by FT synthesis (oxygen-containing compounds/olefms/isoparaffins/normal-paraffins = 10/14/4/72 mass% in this fuel basestock) was then supplied as feed to this reactor and 10 hydrotreating was carried out at a reaction temperature of 250'C or 300'C. For both reaction temperatures, the hydrogen partial pressure was 4.0 MPa, the liquid hourly space velocity of the feed was 2.0 h 1 (200 mL/h as the liquid flow rate), and the hydrogen flow rate was 250 NL/h (i.e., a hydrogen/oil ratio of 1250 NL/L). 15 [0044] The reaction product was subjected to measurement by distillational gas chromatography in order to determine the content of the following: the light fraction with a boiling point below 140'C, oxygen containing compounds, olefins, and isoparaffins. The results are shown in Table 1 (250*C reaction temperature) and Table 2 (300'C reaction 20 temperature). 12 FP07-0094-00 [0045] [Table 1.] Reaction Oxygen- Olefins Isoparaffins Light temperature = containing fraction 250 0 C compounds (mass%) (mass%) (mass%) (mass%) Example 1 0 0 55 3 Example 2 0 0 58 3 Example 3 0 0 69 3 Comparative 3 1 44 3 Example I Comparative 4 1 28 4 Example 2 Comparative 4 2 26 6 Example 3 [0046] [Table 2.] Reaction Oxygen- Olefins Isoparaffins Light temperature = containing fraction 300 0 C compounds (mass%) (mass%) (mass%) (mass%) Example 1 0 0 69 7 Example 2 0 0 74 7 Example 3 0 0 80 7 Comparative 0 0 60 8 Example I Comparative 0 0 38 8 Example 2 Comparative 0 0 36 9 Example 3 [0047] (Example 2) 5 Hydrotreating and reaction product analysis were carried out as in Example 1, with the exception that catalyst 2 was used in place of catalyst 1. The results are shown in Table 1 and Table 2. [0048] (Example 3) 13 FP07-0094-00 A fixed-bed, flow-type reactor was filled with Catalyst 3 (100 mL). This catalyst 3 was then activated by carrying out a reduction treatment thereon for 3 hours at 340'C in a hydrogen atmosphere. [0049] Hydrotreating was carried out at a reaction temperature of 5 250'C or 300'C by supplying this reactor with a mixed oil feedstock obtained by mixing, at a 70 : 30 mass ratio, a fuel basestock having a boiling point range of 140 to 360'C and obtained by FT synthesis (the oxygen-containing compounds/olefms/isoparaffins/normal-paraffins = 10/14/4/72 mass% in this fuel basestock) with a desulfurized oil 10 comprising a petroleum-based fuel basestock having a boiling point range of 140 to 360'C. The mixed oil feedstock had the following values: oxygen-containing compounds/olefins/isoparaffms/normal paraffms = 7/11/15/52 mass% and sulfur fraction = 12 mass-ppm. For both reaction temperatures, the hydrogen partial pressure was 4.0 MPa, 15 the liquid hourly space velocity of the feed was 2.0 h- 1 (200 mL/h as the liquid flow rate), and the hydrogen flow rate was 250 NL/h (i.e., a hydrogen/oil ratio of 1250 NL/L). [0050] The reaction product was subjected to measurement by distillational gas chromatography in order to determine the content of the 20 following: the light fraction with a boiling point below 140*C, oxygen containing compounds, olefins, and isoparaffms. The results are shown in Tables 1 and 2. [0051] (Comparative Example 1) Hydrotreating and reaction product analysis were carried out as in 25 Example 1, but in this case using catalyst 4 in place of catalyst 1. The results are shown in Tables 1 and 2. 14 C:VatnbnTDCOWAMU36203_1.DOC-59/201 I - 15 [0052] (Comparative Example 2) Hydrotreating and reaction product analysis were carried out as in Example 1, but in this case using catalyst 5 in place of catalyst 1. The results are shown in Tables 1 and 2. 5 [0053] (Comparative Example 3) Hydrotreating and reaction product analysis were carried out as in Example 1, but in this case using catalyst 6 in place of catalyst 1. The results are shown in Tables I and 2. [0054] As may be understood from the results shown in Tables 1 and 2. good 10 isomerisation from normal-paraffins to isoparaffins was observed in Examples 1 to 3, as was a good reduction in the oxygen-containing compounds in the fuel basestock and a good reduction in the olefins in the fuel basestock. INDUSTRIAL APPLICABILITY [0055] In advantageous embodiments, the present invention provides a method 15 for hydrotreating a fuel basestock that, in addition to being able to eliminate oxygen-containing compounds and carry out olefin hydrogenation, is able to go further and achieve a thorough conversion of normal-paraffin to isoparaffin. [0056] The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that that prior art forms 20 part of the common general knowledge. [0057] Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step 25 or group of integers or steps.