AU2008206002A1 - Processes for production of liquid fuel - Google Patents

Description

FP07-0550-00 DESCRIPTION PROCESSES FOR PRODUCTION OF LIQUID FUEL Technical Field [0001] The present invention relates to a manufacturing method of 5 liquid fuel from paraffmic hydrocarbons by hydrorefining or hydrocracking. Background Art [0002] Restrictions on sulfur contents in liquid fuels such as gasoline and gas oil have rapidly become more stringent in recent years. This 10 has led to ever increasing demand for environmentally friendly, clean liquid fuels with low sulfur and aromatic hydrocarbon contents. In response to this demand, processes for production of various types of clean fuels are already being researched in the fuel oil production industry. A clean fuel can be manufactured by first producing 15 synthetic gas (carbon monoxide and hydrogen) by gasification or reforming using, for example, asphalt, biomass, coal, natural gas or the like as the starting material, and then using the synthetic gas as feedstock for Fischer-Tropsch (FT) synthesis. Also, hydrocracking of waxes as the heavy fraction of FT synthesis products allows production 20 of isoparaffin-rich fuel base stocks, and processes for hydrocracking of paraffmic hydrocarbons such as waxes in the presence of catalysts are considered highly promising. [0003] Because fuel base stocks obtained by FT synthesis are composed mainly of normal paraffins or contain oxygen-containing 25 compounds or olefms, they are generally unsuitable for use as gasoline or gas oil and must be subjected to hydrorefining. The main purpose 1 FP07-0550-00 of hydrorefining is to accomplish removal of oxygen-containing compounds, hydrogenation of olefins (conversion to paraffms) and isomerization of normal paraffins (see Patent documents 1 and 2, for example), and in order to ensure a low-temperature flow property for 5 gas oils it is particularly important to convert normal paraffins to isoparaffms. [0004] In the case of hydrocracking, on the other hand, hydrocracking processes using vacuum gas oils as feedstocks are established techniques with a long history of decades, and many have already been 10 commercialized. However, when paraffmic hydrocarbons are used as feedstocks instead of vacuum gas oils in such hydrocracking processes, the same catalysts for vacuum gas oil cannot be redeployed because the reactivity of paraffinic hydrocarbons in hydrocracking differs significantly from that of vacuum gas oils. Much avid research and 15 development is therefore being carried out with the aim of developing high performance catalysts for paraffmic hydrocarbons, and for example, catalysts comprising platinum supported on supports containing silica-alumina have been proposed (see Patent document 3, for example). 20 [Patent document 1] U.S. Patent Application Specification No. 5378348 [Patent document 2] International Patent Publication No. WO01/057160 [Patent document 3] Japanese Unexamined Patent Publication HEI No. 25 6-41549 Disclosure of the Invention 2 FP07-0550-00 Problems to be Solved by the Invention [0005] Most importance for improving the economy of processes for production of clean fuels is increasing the yields of the target fuel base stocks. In other words, inhibiting decomposition during the 5 hydrorefining is a key to achieving higher economy in these processes. For fuel use, conversion from normal paraffms to isoparaffins helps to improve the octane number for gasoline and to improve the low temperature flow property for gas oil, and is therefore important from the viewpoint of fuel quality. 10 [0006] However, when a fuel base stock containing normal paraffins, oxygen-containing compounds and olefins is used in a hydrorefining process as disclosed in Patent document 1 and 2, it is often difficult to simultaneously achieve isomerization from normal paraffins to isoparaffms, removal of oxygen-containing compounds, hydrogenation 15 of olefms and a high yield of the target fuel base stock. It is especially difficult to achieve both sufficient isomerization from normal paraffms to isoparaffins and a high yield of the target fuel base stocks. [0007] Moreover, the conventional hydrocracking processes employing 20 catalysts such as disclosed in Patent document 3 are in need of improvement in the following points. Specifically, in order to achieve high economy in paraffmic hydrocarbon hydrocracking processes, it is important to ensure (1) high cracking activity of the catalyst and (2) a high middle distillate yield. If the cracking activity of the catalyst is 25 too high, however, the produced middle distillate will decompose more readily resulting in a lower middle distillate yield, and as a result the 3 FP07-0550-00 process economy will be reduced. In other words, because a trade-off exists between (1) and (2) it is exceedingly difficult to achieve both (1) and (2), and this has severely limited improvement in the economy of paraffinic hydrocarbon hydrocracking processes. 5 [0008] In light of these circumstances, it is a first object of the present invention to provide a manufacturing method of liquid fuel that produces isoparaffin-rich fuel base stocks at high yield. It is a second object of the invention to provide a manufacturing method of liquid fuel that, for hydrocracking of feedstocks containing paraffinic 10 hydrocarbons, maintains sufficiently high cracking activity of the catalyst while selectively increasing the middle distillate yield. Means for Solving the Problems [0009] In order to solve the problems described above, the invention provides a manufacturing method of liquid fuel characterized by 15 comprising a step in which a feedstock containing normal paraffins, oxygen-containing compounds and olefins and having a end point in distillation of not higher than 360'C is fractionated at a boundary point in a range of 130-160*C, into a first fraction whose end point in distillation is not higher than the boundary point and a second fraction 20 whose initial boiling point in distillation is not lower than the boundary point, a step in which the first fraction is subjected to hydrorefining using a first catalyst comprising a solid acid-containing support and a metal of Group VIII of the Periodic Table supported on the support, and a step in which the second fraction is subjected to hydrorefining 25 using a second catalyst comprising a solid acid-containing support and a metal of Group VIII of the Periodic Table supported on the 4 FP07-0550-00 support(for convenience, this will hereinafter be referred to as the "first production process"). [0010] In the first production process, the first and second catalysts preferably both contain palladium and/or platinum as the metal of 5 Group VIII of the Periodic Table. [0011] Also, both the first and second catalysts in the first production process preferably contain boron or phosphorus. [0012] The feedstock used as the starting material in the first production process is preferably produced by reduction of carbon 10 monoxide. [0013] The invention further provides a manufacturing method of liquid fuel characterized by obtaining a cracking product oil by hydrocracking that includes contacting a paraffinic hydrocarbon containing feedstock with a catalyst comprising a support that contains 15 crystalline aluminosilicate and an amorphous solid acid, and platinum supported on the support using a platinum compound that does not contain chlorine as a constituent element (for convenience, this will hereinafter be referred to as the "second production process"). [0014] The term "middle distillate" used according to the invention 20 means the fraction with a boiling point range of 145-360*C. The term "hydrocracking" as used according to the invention includes not only cracking of paraffmic hydrocarbons but also isomerization from normal paraffins to isoparaffins. [0015] The feedstock used in the second production process preferably 25 contains at least 70 % by mass normal paraffins. Hydrocracking of such feedstock will allow even higher selective increase in the middle 5 FP07-0550-00 distillate yield while maintaining a sufficiently high level of cracking activity of the catalyst. [0016] The crystalline aluminosilicate in the second production process is preferably ultrastable Y-type zeolite. This can result in even higher 5 selective increase in the middle distillate yield. [0017] Also, the platinum loading amount on the support of the catalyst in the second production process is preferably 0.1-2.0 % by mass with respect to the mass of the support. This will allow still higher selective increase in the middle distillate yield while maintaining a 10 sufficiently high level of cracking activity of the catalyst. [0018] The feedstock in the second production process preferably contains paraffinic hydrocarbons produced by reduction of carbon monoxide. This will allow efficient conversion of normal paraffins to isoparaffins while maintaining high levels of catalyst activity and 15 middle distillate yield. [0019] The proportion of paraffinic hydrocarbons with a boiling point of below 360*C in the cracking product oil with respect to paraffinic hydrocarbons with a boiling point of 360*C or higher in the feedstock in the second production process is preferably at least 70 % by mass. 20 [0020] The platinum compound in the second production process is preferably at least one compound selected from among tetraammineplatinum(II) nitrate and diamminedinitroplatinum (II). Effect of the Invention [0021] With the manufacturing method of liquid fuel according to the 25 invention it is possible to efficiently produce isoparaffm-rich fuel base stocks. Of the two modes of the manufacturing method of liquid fuel 6 FP07-0550-00 according to the invention, the second production process allows a particularly high level of selective increase in middle distillate yield to be achieved while maintaining sufficiently high catalyst activity for production of liquid fuels by hydrocracking from paraffinic 5 hydrocarbon-containing feedstocks. Best Mode for Carrying Out the Invention [0022] Preferred modes of the invention will now be described in detail. [0023] [First mode] 10 The first mode described below is a preferred mode of the first production process described above. According to the first mode, the feedstock for hydrorefming is feedstock containing normal paraffins, oxygen-containing compounds and olefins and having an end point in distillation of not higher than 360'C. The phrase "feedstock ... having 15 an end point in distillation of not higher than 360'C" means that when the feedstock used for the invention is obtained by distillation, "the feedstock is obtained by distillation with a target end point in distillation of not higher than 360*C". In other words, when conducting a procedure to obtain a fraction of not higher than 360'C 20 using ordinary commercial distillation equipment, the obtained fraction often contains small amounts of fractions with boiling points of higher than 360*C, and these fractions are also included within the concept of "feedstock ... having a end point in distillation of not higher than 360*C". However, the content of fractions with boiling points of 25 higher than 360*C in the feedstock is preferably 10 % by mass or less, and more preferably 5 % by mass or less based on the total amount of 7 FP07-0550-00 the feedstock. [0024] The feedstock may be a petroleum basestock or synthetic basestock, or a mixture of a petroleum basestock and synthetic basestock. The feedstock will normally be composed mainly of 5 normal paraffins, but there are no particular restrictions on the normal paraffin content and it will usually be 60 % by mass or more, and preferably 70 % by mass or more. There are also no particular restrictions on the amounts of oxygen-containing compounds and olefins, but they are both preferably not greater than 20 % by mass 10 based on the total amount of the feedstock. If the content of oxygen containing compounds and/or olefins excesses 20 % by mass, the heat release value during hydrorefining will be increased, tending to interfere with control of the reaction temperature. [0025] According to the first mode, the feedstock is fractionated at a 15 boundary point in a range of 130-160*C, prior to hydrorefining, into a first fraction whose end point in distillation is not higher than the boundary point and a second fraction whose initial boiling point in distillation is not lower than the boundary point. Fractionation of the first fraction and second fraction may be carried out, for example, by 20 atmospheric distillation using a distilling apparatus such as a distillation column. [0026] The boundary point between the first fraction and second fraction is selected within the range of 130-160'C as mentioned above, but it is preferably 135-150*C and more preferably 140-145*C. As an 25 especially preferred example there may be mentioned a mode in which the boundary point between the first fraction and second fraction is set 8 FP07-0550-00 to 145*C for fractionation into a first fraction (naphtha fraction) whose end point in distillation is below 145'C and a second fraction (middle distillate) whose initial boiling point in distillation is 145'C or higher. The initial boiling point of the first fraction is not particularly restricted 5 but will normally be 5'C or higher for naphtha fractions. The end point of the second fraction is also not particularly restricted but will normally be not higher than 360*C. The naphtha fraction may be suitably used as a gasoline basestock, while the middle distillate may be suitably used as a gas oil basestock. 10 [0027] The first and second fractions that have been fractionated in this manner are then subjected to hydrorefining by contact with a specific catalyst. [0028] For hydrorefining of the first fraction there is used a first catalyst comprising a solid acid-containing support and a metal of 15 Group VIII of the Periodic Table supported on the support. As solid acids to be included in the support of the first catalyst there may be mentioned amorphous solid acids such as silica-alumina, silica zirconia, alumina-boria, silica-magnesia, heteropolyacids and zirconia sulfate, and aluminophosphate (SAPO- 11), crystalline aluminosilicates 20 such as USY, mordenite, ferrierite, ZSM-22, ZSM-23, beta-zeolite and the like. [0029] The support of the first catalyst may also contain a binder for molding. There are no particular restrictions on the binder, and as preferred binders there may be mentioned alumina and silica. The 25 form of the support is not particularly restricted and may be particles, cylinders (pellets) or the like. A support also containing phosphorus 9 FP07-0550-00 and/or boron is effective for promoting the isomerization reaction. There are no particular restrictions on the phosphorus and/or boron contents, but the total content of phosphorus and boron is preferably 0.1-2.0 % by mass. A total phosphorus/boron content of less than 0.1 5 % by mass will tend to insufficiently promote the isomerization reaction, while a total content of greater than 2.0 % by mass will tend to result in inadequate strength of the molded catalyst. As examples of methods for introducing phosphorus into catalysts there may be mentioned methods of adding phosphorus-containing compounds such 10 as phosphoric acid or phosphorus pentaoxide to binders before calcination (for an alumina binder which is the boehmite state, same hereunder). As examples of methods for introducing boron into catalysts there may be mentioned methods of adding boron-containing compounds such as boric acid to binders before calcination. Such 15 introduction of phosphorus or boron will not always be necessary when the solid acid contains phosphorus or boron, such as when alumina boria is used as the solid acid, but the aforementioned methods for introducing phosphorus and boron are useful for adjusting the phosphorus or boron content in the catalyst. 20 [0030] The metal of Group VIII of the Periodic Table supported on the support of the first catalyst may be, specifically, nickel, rhodium, palladium, iridium, platinum or the like, with palladium and platinum being preferred among these. The amount of metal supported is not particularly restricted but is preferably 0.1-2.0 % by mass based on the 25 total amount of the catalyst. [0031] Hydrorefining of the first fraction may be carried out using a 10 FP07-0550-00 fixed bed reactor packed with the first catalyst. The reaction temperature for hydrorefining of the first fraction is not particularly restricted but is preferably in the range of 200-380*C. A reaction temperature of below 200*C will significantly reduce isomerization of 5 the normal paraffins, while a reaction temperature of above 380'C will tend to lighten the first fraction and lower the yield of the desired fuel base stock. The reaction pressure for hydrorefining of the first fraction is not particularly restricted but is preferably 1-12 MPa and more preferably 2-6 MPa. A reaction pressure of below 1 MPa will tend to 10 promote deterioration of the catalyst, while a reaction pressure of above 12 MPa will tend to raise the reaction temperature. The liquid space velocity for hydrorefining of the first fraction is not particularly restricted but is preferably 0.1-5.0 h 1 . The ratio of oil to total hydrogen supplied is also not particularly restricted but is preferably 15 100-850 NL/L. [0032] For hydrorefining of the second fraction there is used a second catalyst comprising a solid acid-containing support and a metal of Group VIII of the Periodic Table supported on the support. As solid acids in the support of the second catalyst there may be used 20 amorphous solid acids such as silica-alumina and silica-zirconia, and crystalline aluminosilicates such as SAPO- 11, USY, ZSM-22 and the like. Using acid catalysts other than those mentioned above is not preferred because they may drastically lower the middle distillate yield after hydrorefming. 25 [0033] The support of the second catalyst may also contain a binder for molding. There are no particular restrictions on the binder, and as 11 FP07-0550-00 preferred binders there may be mentioned alumina and silica. The form of the support is also not particularly restricted and may be particles, cylinders (pellets) or the like. A support containing phosphorus and/or boron is effective for promoting the isomerization 5 reaction. There are no particular restrictions on the phosphorus and/or boron contents, but the total of phosphorus and boron is preferably 0.1 2.0 % by mass. A total phosphorus/boron content of less than 0.1 % by mass will tend to insufficiently promote the isomerization reaction, while a total content of greater than 2.0 % by mass will tend to result in 10 inadequate strength of the molded catalyst. As examples of methods for introducing phosphorus into catalysts there may be mentioned methods of adding phosphorus-containing compounds such as phosphoric acid or phosphorus pentaoxide to binders before calcination (for an alumina binder which is the boehmite state, same hereunder). 15 As examples of methods for introducing boron into catalysts there may be mentioned methods of adding boron-containing compounds such as boric acid to binders before calcination. Such introduction of phosphorus or boron will not always be necessary when the solid acid contains phosphorus or boron, such as when alumina-boria is used as 20 the solid acid, but the aforementioned methods for introducing phosphorus and boron are useful for adjusting the phosphorus or boron content in the catalyst. [0034] The metal of Group VIII of the Periodic Table supported on the support of the second catalyst may be, specifically, nickel, rhodium, 25 palladium, iridium, platinum or the like, with palladium and platinum being preferred among these. The amount of metal supported is not 12 FP07-0550-00 particularly restricted but is preferably 0.1-2.0 % by mass based on the total amount of the catalyst. [0035] Hydrorefining of the second fraction may be carried out using a fixed bed reactor packed with the second catalyst. The reaction 5 temperature for hydrorefining of the second fraction is not particularly restricted but is preferably in the range of 180-360*C. A reaction temperature of below 180*C will significantly reduce isomerization of the normal paraffins, while a reaction temperature of above 360C will tend to lighten the second fraction and lower the yield of the desired 10 fuel base stock. The reaction pressure for hydrorefining of the second fraction is not particularly restricted but is preferably 1-12 MPa and more preferably 2-6 MPa. A reaction pressure of below I MPa will tend to promote deterioration of the catalyst, while a reaction pressure of above 12 MPa will tend to raise the reaction temperature. The 15 liquid space velocity for hydrorefining of the second fraction is not particularly restricted but is preferably 0.1-4.0 h-. The ratio of oil to total hydrogen supplied is also not particularly restricted but is preferably 100-850 NL/L. [0036] Thus, according to the first mode it is possible to produce an 20 isoparaffin-rich fuel base stock at a high yield by fractionating a feedstock containing normal paraffins, oxygen-containing compounds and olefins and having an end point in distillation of not higher than 360*C, at a boundary point in a range of 130-160*C, into a first fraction whose end point in distillation is not higher than the boundary point 25 and a second fraction whose initial boiling point in distillation is not lower than the boundary point, and subjecting the first and second 13 FP07-0550-00 fractions to hydrorefining using catalysts (first and second catalysts) each comprising a solid acid-containing support and a metal of Group VIII of the Periodic Table supported on the support. The fuel base stock obtained by hydrorefining of the first fraction is most preferably a 5 gasoline basestock. The fuel base stock obtained by hydrorefining of the second fraction is most preferably a gas oil basestock. The fuel base stock obtained by hydrorefming of the second fraction may include a kerosene fraction (fraction with a boiling point range of 145 260*C) and gas oil fraction (fraction with a boiling point range of 260 10 360*C), and the kerosene fraction and gas oil fraction may be separated using a distilling apparatus after hydrorefining. [0037] Incidentally, the first production process of the invention is not limited to the first mode described above. For example, the technique employed in the second mode described hereunder may be applied for 15 the first production process. [0038] [Second mode] The second mode described below is a preferred mode of the second production process described above. For the second mode there is used a catalyst comprising a support that contains crystalline 20 aluminosilicate and an amorphous solid acid, and platinum supported using a platinum compound that does not contain chlorine as a constituent element. A crystalline aluminosilicate is a crystalline metal oxide composed of the three elements aluminum, silicon and oxygen. Other metal elements may be included in a range that does 25 not interfere with the effect of the invention, but the proportion of other metal elements with respect to the total of alumina and silica is 14 FP07-0550-00 preferably not greater than 5 % by mass and more preferably not greater than 3 % by mass as oxides. As metal elements to be included there may be mentioned titanium, lanthanum, manganese, gallium and zinc, among which titanium and lanthanum are preferred from the 5 viewpoint of obtaining a high middle distillate yield. [0039] The crystallinity of the aluminosilicate can be estimated by the proportion of tetracoordinated aluminum atoms among the total aluminum atoms, and this proportion can be measured by 27 AI solid NMR. According to the invention, a crystalline aluminosilicate is an 10 aluminosilicate with a proportion of at least 70% tetracoordinated aluminum atoms among the total aluminum atoms. That is, it can be used as a crystalline aluminosilicate for the second mode if the proportion is at least 70%. In most cases the proportion will be at least 80% and preferably 85% or greater. 15 [0040] Zeolite may be used as a crystalline aluminosilicate. Preferred crystalline aluminosilicates are Y- or ultrastable Y (USY) - type zeolite, beta zeolite and mordenite, with ultrastable Y(USY)- type zeolite being more preferred. If necessary, two or more different crystalline aluminosilicates may be used in combination. 20 [0041] The mean particle size of the crystalline aluminosilicate is not particularly restricted but is preferably not greater than 1.0 gm and even more preferably not greater than 0.5 pm. A smaller particle size of the crystalline aluminosilicate is preferred as this will tend to increase the middle distillate yield in the cracking product oil. 25 [0042] There are no particular restrictions on the crystalline aluminosilicate content, but for most purposes it may be in the range of 15 FP07-0550-00 0.1-20 % by mass based on the total mass of the support. [0043] As amorphous solid acids in the support there may be mentioned silica-alumina, silica-zirconia, silica-titania, silica-magnesia, alumina-zirconia, alumina-boria and the like. Of these, silica-alumina 5 and alumina-boria are preferred from the viewpoint of both catalyst activity and high middle distillate yield. [0044] There are no particular restrictions on the amount of amorphous solid acid, but for most purposes it will be in the range of 5-70 % by mass based on the total mass of the support. 10 [0045] A support containing the aforementioned crystalline aluminosilicate and amorphous solid acid will allow molding of the crystalline aluminosilicate and amorphous solid acid without using a binder, although a binder may be used for molding to prepare a molded article as the support. There are no particular restrictions on the 15 binder used, and it may be alumina, silica or the like, and preferably alumina. There are also no particular restrictions on the proportion of binder used for molding, but it is preferably 20-90 % by mass and more preferably 40-80 % by mass based on the total mass of the support. If the binder proportion is less than 20 % by mass the support strength 20 will tend to be weak, while if it is greater than 90 % by mass the effect of the invention may not be adequately achieved. [0046] The catalyst comprises platinum supported on a support containing the aforementioned crystalline aluminosilicate and amorphous solid acid. 25 [0047] Selection of the platinum compound used for loading of platinum onto the support is particularly important, and the second 16 FP07-0550-00 mode employs a platinum compound that does not contain chlorine as a constituent element. The platinum compound may be any compound that does not contain chlorine as a constituent element, and specifically preferred are tetraammineplatinum(II) nitrate, and 5 diamminedinitroplatinum (II). [0048] The platinum compound preferably contains even chlorine impurities as little as possible. This will facilitate preparation of a catalyst with a satisfactorily reduced chlorine concentration. [0049] There are no particular restrictions on the method of loading the 10 platinum, and for most purposes impregnation, incipient wetness or ion exchange methods may be employed. The loading amount of platinum with respect to the support is preferably 0.1-2.0 % by mass and more preferably 0.4-1.2 % by mass based on the mass of the support. A platinum loading amount of less than 0.1 % by mass will 15 tend to reduce the middle distillate yield, while a platinum loading amount of greater than 2.0 % by mass will tend to lower the catalyst activity. [0050] Palladium may also be loaded on the support in addition to platinum. There are no particular restrictions on the method of 20 loading the palladium, and for example, it may be loaded on the support simultaneously with platinum. When palladium is loaded, it is important that the palladium compound contain no chlorine as a structural element. Specifically, palladium nitrate, palladium acetate, tetraamminepalladium(II) nitrate, diamminedinitropalladium(II) and 25 the like may be used. [0051] When the catalyst comprises both platinum and palladium, the 17 FP07-0550-00 proportion of palladium to platinum (as the molar ratio of palladium/platinum) is preferably not greater than 1.5 and more preferably 0.2-0.8. If the proportion exceeds 1.5 the yield of the middle distillate will tend to be reduced. 5 [0052] As feedstocks there may be used petroleum-based and synthetic hydrocarbon oils, with paraffmic hydrocarbons being preferred. A paraffmic hydrocarbon is a hydrocarbon oil containing at least 70 % by mass normal paraffms. The feedstock is more preferably a C18 or greater paraffinic hydrocarbon that is solid at ordinary temperature, or 10 in other words, a "wax" paraffinic hydrocarbon. Waxes with boiling points of 360*C or higher at ordinary pressure are especially preferred. [0053] There are no particular restrictions on the method of producing the paraffmic hydrocarbon in the feedstock, but preferred are FT waxes produced by carbon monoxide reduction in Fischer-Tropsch synthesis. 15 [0054] A conventional fixed bed reactor may be used for hydrocracking. The reaction conditions for the feedstock and catalyst in a fixed bed reactor are preferably a temperature of 200-450*C, a hydrogen pressure of 0.5-15 MPa and a feedstock liquid space velocity of 0.1-10/h, and more preferably a temperature of 250-370'C, a 20 hydrogen pressure of 2.0-8.0 MPa and a feedstock liquid space velocity of 0.3-5.0/h. [0055] The cracking product oil obtained by hydrocracking will contain not only the middle distillate (fraction with a boiling point range of 145-360*C) as the major component but also fractions with 25 boiling points of below 145'C (LPG, naphtha fraction, etc.) and fractions with boiling points of above 360*C. The middle distillate 18 FP07-0550-00 may be separated by distillation or the like into the kerosene fraction (fraction with boiling point range of 145-260*C) and gas oil fraction (fraction with boiling point range of 260-360*C). [0056] Incidentally, the second production process of the invention is 5 not limited to the second mode described above. For example, the technique employed in the first mode described above may be applied for the second production process. Examples [0057] The present invention will now be explained in greater detail 10 based on examples and comparative examples, with the understanding that these examples are in no way limitative on the invention. [0058] [Example 1-1] (Preparation of feedstocks and fractionation of first and second fractions) 15 A fixed bed reactor was packed with 20 g of an FT synthesis catalyst comprising 20 % by mass Co and 2.4 % by mass Zr supported on a silica support with a particle size of 1.5 mm, and carbon monoxide reduction was conducted (FT synthesis). The reaction conditions were GHSV = 1500 h~1, pressure = 2.5 MPa, temperature = 225'C. 20 After removing the water from the product, it was subjected to atmospheric distillation to obtain a naphtha fraction as the first fraction and a middle distillate as the second fraction. The properties of the naphtha fraction and middle distillate are shown in Table 1. 19 FP07-0550-00 [0059] [Table 1] First fraction Second fraction (naphtha (middle fraction) distillate) Distillation Initial boiling point ('C) 5 145 properties End point (C) 145 360 Normal paraffins (% by 76 82 Composition mass) Isoparaffins (% by mass) 2 2 Olefins (% by mass) 12 10 Oxygen-containing 10 6 compounds (% by mass) [0060] (Hydrorefming) A fixed bed reactor was packed with 20 g of a catalyst comprising 5 platinum supported on a silica-alumina support (alumina content: 14 % by mass, platinum content: 0.4 % by mass), and the fixed bed reactor was used for hydrorefining of the first fraction under a hydrogen stream. The reaction temperature was 300'C, the pressure was 3.5 MPa and the liquid space velocity was 2.0 h-1. A separate fixed bed 10 reactor was packed with 20 g of a catalyst comprising platinum supported on a silica-alumina support (alumina content: 14 % by mass, platinum content: 0.4 % by mass), and the fixed bed reactor was used for hydrorefining of the second fraction under a hydrogen stream. The reaction temperature was 300'C, the pressure was 3.5 MPa and the 15 liquid space velocity was 2.0 h 1 . Each of the product oils obtained by hydrorefining of the first fraction and the second fraction was analyzed by gas chromatography, and the yields of the gas (component with a 20 FP07-0550-00 boiling point range of 5*C or lower), naphtha fraction (component with a boiling point range of 5-145*C) and middle distillate (component with a boiling point range of 145-360*C) and the ratio of isoparaffins in the naphtha fraction and middle distillate were determined. The 5 results are shown in Table 2. For comparison with Comparative Example 1-1 and other comparative examples described hereunder, Table 2 shows the values averaged for a mixture of the product oil obtained by hydrorefining of the first fraction and the product oil obtained by hydrorefining of the second fraction (50:50 mass ratio 10 mixture) (same for Examples 1-2 and 1-3). Gas chromatography of the product oils in this example confirmed that hydrogenation reaction had been adequately promoted, with no detectable oxygen-containing compounds or olefin compounds. [0061] (Comparative Example 1-1) 15 The same FT synthesis was carried out as in Example 1-1, and the obtained first fraction and second fraction were mixed mass ratio of 50:50. Next, a fixed bed reactor was packed with 20 g of a catalyst comprising platinum supported on a silica-alumina support(alumina content: 14 % by mass, platinum content: 0.4 % by mass), and the fixed 20 bed reactor was used for hydrorefining of the mixed feedstock under a hydrogen stream. The reaction temperature was 300*C, the pressure was 3.5 MPa and the liquid space velocity was 2.0 h~ 1 . Each of the product oils was analyzed by gas chromatography, and the yields of the gas, naphtha fraction and middle distillate and the ratio of isoparaffins 25 in the naphtha fraction and middle distillate were determined. The results are shown in Table 2. No oxygen-containing compounds or 21 FP07-0550-00 olefin compounds were detected in gas chromatography of the product oils in this comparative example. [0062] (Example 1-2) First, FT synthesis was carried out in the same manner as Example 1-1 5 to obtain first and second fractions having the properties listed in Table 1. A fixed bed reactor was packed with 20 g of a catalyst having 0.5 % by mass platinum supported on a support comprising 3 % by mass USY zeolite (silica/alumina molar ratio: 36) and 97 % by mass of an alumina binder, and the fixed bed reactor was used for hydrorefining of 10 the first fraction under a hydrogen stream. The reaction temperature was 295 C, the pressure was 3 MPa and the liquid space velocity was 2.0 h-'. Also, a fixed bed reactor was packed with 20 g of a catalyst having 0.5 % by mass platinum supported on a support comprising 3 % by mass USY zeolite (silica/alumina molar ratio: 36) and 97 % by mass 15 of an alumina binder, and the fixed bed reactor was used for hydrorefining of the second fraction under a hydrogen stream. The reaction temperature was 295*C, the pressure was 3 MPa and the liquid space velocity was 2.0 h- 1 . Each of the product oils obtained by hydrorefining of the first fraction and the second fraction was analyzed 20 by gas chromatography, and the yields of the gas, naphtha fraction and middle distillate and the ratio of isoparaffms in the naphtha fraction and middle distillate were determined. The results are shown in Table 2. Gas chromatography of the product oils in this example confirmed that hydrogenation reaction had been adequately promoted, with no 25 detectable oxygen-containing compounds or olefin compounds. [0063] (Comparative Example 1-2) 22 FP07-0550-00 The same FT synthesis was carried out as in Example 1-1, and the obtained first fraction and second fraction were mixed to mass ratio of 50:50. A fixed bed reactor was packed with 20 g of a catalyst having 0.5 % by mass platinum supported on a support comprising 3 % by 5 mass USY zeolite (silica/alumina molar ratio: 36) and 97 % by mass of an alumina binder, and the fixed bed reactor was used for hydrorefining of the feedstock mixture under a hydrogen stream. The reaction temperature was 295*C, the pressure was 3 MPa and the liquid space velocity was 2.0 h~ 1 . Each of the product oils was analyzed by gas 10 chromatography, and the yields of the gas, naphtha fraction and middle distillate and the ratio of isoparaffins in the naphtha fraction and middle distillate were determined. The results are shown in Table 2. No oxygen-containing compounds or olefin compounds were detected in gas chromatography of the product oils in this comparative example. 15 [0064] (Example 1-3) First, FT synthesis was carried out in the same manner as Example 1-1 to obtain first and second fractions having the properties listed in Table 1. A fixed bed reactor was packed with 20 g of a catalyst having 0.8 % by mass platinum supported on a support comprising 70 % by mass 20 SAPO- 11 and 30 % by mass of an alumina binder, and the fixed bed reactor was used for hydrorefining of the first fraction under a hydrogen stream. The reaction temperature was 290*C, the pressure was 4 MPa and the liquid space velocity was 1.5 h-'. Also, a fixed bed reactor was packed with 20 g of a catalyst having 0.8 % by mass 25 platinum supported on a support comprising 70 % by mass SAPO- 11 and 30 % by mass of an alumina binder, and the fixed bed reactor was 23 FP07-0550-00 used for hydrorefming of the second fraction under a hydrogen stream. The reaction temperature was 290*C, the pressure was 4 MPa and the liquid space velocity was 1.5 h~1. Each of the product oils obtained by hydrorefining of the first fraction and the second fraction was analyzed 5 by gas chromatography, and the yields of the gas, naphtha fraction and middle distillate and the ratio of isoparaffms in the naphtha fraction and middle distillate were determined. The results are shown in Table 2. Gas chromatography of the product oils in this example confirmed that hydrogenation reaction had been adequately promoted, with no 10 detectable oxygen-containing compounds or olefin compounds. [0065] (Comparative Example 1-3) The same FT synthesis was carried out as in Example 1-1, and the obtained first fraction and second fraction were mixed to mass ratio of 50:50. A fixed bed reactor was packed with 20 g of a catalyst having 15 0.8 % by mass platinum supported on a support comprising 70 % by mass SAPO- 11 and 30 % by mass of an alumina binder, and the fixed bed reactor was used for hydrorefining of the feedstock mixture under a hydrogen stream. The reaction temperature was 290*C, the pressure was 4 MPa and the liquid space velocity was 1.5 h~'. Each of the 20 product oils was analyzed by gas chromatography, and the yields of the gas, naphtha fraction and heart-cut fraction and the ratio of isoparaffins in the naphtha fraction and middle distillate were determined. The results are shown in Table 2. No oxygen-containing compounds or olefin compounds were detected in gas chromatography of the product 25 oils in this comparative example. 24 FP07-0550-00 [0066] [Table 2] Gas Naphtha fraction Middle distillate Yield Yield Isoparaffins Yield Isoparaffins (% by (% by (% by (% by (% by mass) mass) mass) mass) mass) Example 1-1 4.8 47.0 65.2 48.2 60.5 Comp. Ex. 6.4 46.5 63.8 47.1 60.2 1-1 Example 1-2 8.8 45.8 42.8 45.4 46.0 Comp. Ex. 10.1 45.7 43.6 44.2 48.8 1-2 Example 1-3 2.0 49.8 62.4 48.2 68.9 Comp. Ex. 3.1 49.6 61.1 47.3 67.1 1-3 [0067] As shown in Table 2, Examples 1-1 to 1-3 successfully achieved a high level of oxygen-containing compound removal, olefin 5 hydrogenation and isomerization of normal paraffins to isoparaffins, as well as a high yields of the target fuel base stocks (naphtha fraction and middle distillate), compared to Comparative Examples 1-1 to 1-3. [0068] (Preparation of catalyst A) After combining 30 g of ultrastable Y (USY) - type zeolite with a mean 10 particle size of 0.6 pm (silica/alumina molar ratio = 3:1), 500 g of silica-alumina (alumina content: 14 % by mass) and 400 g of boehmite, the mixture was used to form a cylindrical molded article with a diameter of 1/16 inch (approximately 1.6 mm). The cylindrical molded article was calcined in air at 500*C for 1 hour to obtain a 15 support. The incipient wetness method was used for impregnation of 25 FP07-0550-00 the support with an aqueous solution of tetraammineplatinum(II) nitrate to 0.8 % by mass platinum based on the support mass. After impregnation, it was dried at 120'C for 3 hours and calcined at 500*C for 1 hour to obtain catalyst A. 5 [0069] (Preparation of catalyst B) Catalyst B was prepared in the same manner as catalyst A, except that alumina-boria (boria content: 15 % by mass) was used instead of silica alumina (alumina content: 14 % by mass). [0070] (Preparation of catalyst C) 10 The incipient wetness method was used for impregnation of a support obtained in the same manner as for preparation of catalyst A, with an aqueous solution containing tetraammineplatinum(II) nitrate and palladium nitrate (palladium/platinum molar ratio = 0.61), to 0.6 % by mass platinum and 0.2 % by mass palladium based on the mass of the 15 support. After impregnation, it was dried at 120*C for 3 hours and calcined at 500'C for 1 hour to obtain catalyst C. [0071] (Preparation of catalyst D) Catalyst D was prepared in the same manner as catalyst A, except that platinic chloride was used instead of tetraammineplatinum(II) nitrate. 20 [0072] (Preparation of catalyst E) Catalyst E was prepared in the same manner as catalyst B, except that platinic chloride was used instead of tetraammineplatinum(II) nitrate. [0073] (Example 2-1) FT wax (normal paraffin content: 95 % by mass, carbon number 25 distribution: 21-60, content of fraction with boiling point 360*C or higher: 100 % by mass) was supplied as feedstock to a fixed bed 26 FP07-0550-00 circulating reactor packed with catalyst A (100 ml) for hydrocracking. The hydrogen pressure during hydrocracking was 3 MPa, and the liquid space velocity of the feedstock was 2.0/h. The reaction temperature giving 80 % by mass cracking product (fraction with boiling point 5 360'C or lower) with respect to the feedstock (80 % by mass cracking temperature) and the middle distillate yield (fraction with boiling point range of 145-360'C) with respect to the feedstock at that reaction temperature were determined for this hydrocracking. The results are shown in Table 3. 10 [0074] (Example 2-2) Hydrocracking was carried out in the same manner as Example 2-1 except for using catalyst B instead of catalyst A, and the 80 % by mass cracking temperature and middle distillate yield were determined. The results are shown in Table 3. 15 [0075] (Example 2-3) Hydrocracking was carried out in the same manner as Example 2-1 except for using catalyst C instead of catalyst A, and the 80 % by mass cracking temperature and middle distillate yield were determined. The results are shown in Table 3. 20 [0076] (Comparative Example 2-1) Hydrocracking was carried out in the same manner as Example 2-1 except for using catalyst D instead of catalyst A, and the 80 % by mass cracking temperature and middle distillate yield were determined. The results are shown in Table 3. 25 [0077] (Comparative Example 2-2) Hydrocracking was carried out in the same manner as Example 2-1 27 FP07-0550-00 except for using catalyst E instead of catalyst A, and the 80 % by mass cracking temperature and middle distillate yield were determined. The results are shown in Table 3. [0078] [Table 3] 80 % by mass Cracking Middle distillate temperature (*C) yield (% by mass) Example 2-1 299 56.0 Example 2-2 300 62.0 Example 2-3 297 56.8 Comp. Ex. 2- 302 54.8 1 Comp. Ex. 2- 305 60.4 2 5 [0079] As shown in Table 3, Examples 2-1 to 2-3 had low 80 % by mass cracking temperatures and high middle distillate yields compared to Comparative Examples 2-1 and 2-2. 28

Claims (11)

1. A manufacturing method of liquid fuel characterized by comprising : a step in which a feedstock containing normal paraffins, 5 oxygen-containing compounds and olefins and having an end point in distillation of not higher than 360*C is fractionated at a boundary point in a range of 130-160*C, into a first fraction whose end point in distillation is not higher than the boundary point and a second fraction whose initial boiling point in distillation is not lower than the boundary 10 point, a step in which the first fraction is subjected to hydrorefining using a first catalyst comprising a solid acid-containing support and a metal of Group VIII of the Periodic Table supported on the support, and a step in which the second fraction is subjected to hydrorefining 15 using a second catalyst comprising a solid acid-containing support and a metal of Group VIII of the Periodic Table supported on the support.

2. A manufacturing method of liquid fuel according to claim 1, characterized in that the first and second catalysts both contain palladium and/or platinum as the metal of Group VIII of the Periodic 20 Table.

3. A manufacturing method of liquid fuel according to claim 1 or 2, characterized in that the first and second catalysts both contain boron or phosphorus.

4. A manufacturing method of liquid fuel according to any one 25 of claims 1 to 3, characterized in that the feedstock is produced by reduction of carbon monoxide. 29 FP07-0550-00

5. A manufacturing method of liquid fuel characterized by obtaining a cracking product oil by hydrocracking that includes contacting a paraffmic hydrocarbon-containing feedstock with 5 a catalyst comprising a support that contains crystalline aluminosilicate and an amorphous solid acid, and platinum supported on the support using a platinum compound containing no chlorine as a constituent element.

6. A manufacturing method of liquid fuel according to claim 5, 10 characterized in that the feedstock comprises at least 70 % by mass of normal paraffms.

7. A manufacturing method of liquid fuel according to claim 5 or 6, characterized in that the crystalline aluminosilicate is ultrastable Y - type zeolite. 15

8. A manufacturing method of liquid fuel according to any one of claims 5 to 7, characterized in that the loading amount of platinum supported on the support is 0.1-2.0 % by mass with respect to the mass of the support.

9. A manufacturing method of liquid fuel according to any one 20 of claims 5 to 8, characterized in that the feedstock contains paraffmic hydrocarbons produced by reduction of carbon monoxide.

10. A manufacturing method of liquid fuel according to any one of claims 5 to 9, characterized in that the proportion of paraffmic hydrocarbons with a boiling point of lower than 360*C in the cracking 25 product oil is at least 70 % by mass with respect to the paraffmic hydrocarbons with a boiling point of 360*C or higher in the feedstock. 30 FP07-0550-00

11. A manufacturing method of liquid fuel according to any one of claims 5 to 10, characterized in that the platinum compound is at least one compound selected from among tetraammineplatinum(II) nitrate and diamminedinitroplatinum (II). 31