JPS61191517A - Production of hydrocarbon rich in isoparaffin - Google Patents

Abstract

PURPOSE:To produce a hydrocarbon mixture rich in 4-12C isoparaffins in a high yield by bringing a gaseous mixture contg. CO and H2 into contact with a specified catalyst mixture. CONSTITUTION:The 1st catalyst contg. at least one kind of element selected among Co, Fe, Lu and Ni and having capacity to synthesize hydrocarbon from synthesis gas if mixed with the 2nd catalyst in 3:1-1:5 ratio to obtain a catalyst mixture. The 1st catalyst includes molten iron. The 2nd catalyst is produced by supporting at least one kind of element selected among Fe, Co, Ni, Lu, Rh, Pd, Os, Ir, Pt, Cu, V, Cr, Mo and W on a zeolite carrier having 8-13Angstrom pore diameter. A gaseous mixture contg. CO and H2 in 4-0.5 molar ratio of H2/CO is brought into contact with the catalyst mixture under the conditions of atmospheric pressure -40kg/cm<2>G, 100-20,000l/hr space velocity and 160-300 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION OBJECTS OF THE INVENTION [Industrial Field of Application] This invention provides a method for converting hydrocarbons rich in isoparaffins and gasoline fractions from gases containing carbon monoxide and hydrogen using an improved catalyst. Regarding the manufacturing method.

[Prior Art] The Fischer-Dropsch synthesis method has been known for a long time as a method for producing hydrocarbons for liquid fuel from a gas containing carbon monoxide and hydrogen (hereinafter simply referred to as synthesis gas). In this method, a catalyst supporting elements such as cobalt, iron, ruthenium, and nickel is brought into contact with synthesis gas, but the carbon atom selectivity of the hydrocarbons produced is poor, and the number of carbon atoms suitable for gasoline is poor. In addition to hydrocarbons with numbers 5 to 12, a large amount of hydrocarbons with fewer carbon atoms and those with more carbon atoms are produced, and because the normal paraffin content in the hydrocarbons produced is high, the resulting hydrocarbon mixture It has disadvantages such as the low octane number of the gasoline fraction obtained from.

Many efforts have been made to improve these drawbacks of the old Fischer-Dropsch synthesis method, and US Pat. No. 4,096
163, 4180516, 4188336, 40
86262, 3894102, 4157338, 4093643, etc. For example, there is a known method of first synthesizing methanol from synthesis gas using a well-known method, and then producing a mixed hydrocarbon mixture containing mainly paraffins and aromatic hydrocarbons and rich in gasoline fractions with a high octane number using zeolite as a catalyst. There is. However, this method requires relatively high pressure and
Since it is a step reaction, it is an economically disadvantageous method in terms of both reduced energy efficiency and complicated production equipment. In order to improve this disadvantage, we are researching a method to achieve the above objective by a one-stage reaction method by mixing a well-known methanol synthesis catalyst that uses copper, zinc, and chromium with a zeolite catalyst that converts methanol into hydrocarbons. Many efforts have been published. However, in such a one-step reaction method, the optimum temperature for use of the methanol synthesis catalyst and the optimum temperature for use of the zeolite catalyst are different, so it is difficult to find a common optimum temperature necessary to achieve the above objective. This is an unsatisfactory method from a practical point of view because it tends to cause precipitation and accumulation. As another example, a one-step reaction method is also known in which a conventional Fischer-Tropsch catalyst is used in combination with a catalyst called ZSM-5 in which a heavy metal element is supported on a zeolite having a small pore size. Even in the case of this mixed/gold catalyst, the Fischer-Tropsch catalyst and the zeolite catalyst have different optimal operating temperatures, so in order to make the zeolite catalyst work effectively, a high temperature of 300°C or higher and usually 350°C or higher is required. This results in unfavorable results such as a large amount of gaseous hydrocarbons being produced, and a portion of the hydrocarbons being produced being converted into aromatic hydrocarbons with the precipitation of carbon.

[Problems to be Solved by the Invention] In view of the actual state of the prior art as described above, the present inventors have developed a method for producing mixed hydrocarbons rich in isoparaffins having 4 to 12 carbon atoms (hereinafter simply referred to as hydrocarbons) from synthesis gas through a one-step reaction. As a result of many experimental studies on catalysts for producing ``hydrogen'' with high yield, we arrived at the catalyst for the method of the present invention.

"Structure of the Invention" [Means for Solving the Problems] In the method of this invention, at least one element selected from the group consisting of cobalt, iron, ruthenium, and nickel is contained, and itself is carbonized from the synthesis gas. from iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium, platinum, copper, vanadium, chromium, molybdenum, and tungsten to a first catalyst capable of synthesizing hydrogen and a zeolite support whose pore size is 8 Å or more. A mixed catalyst with a second catalyst supporting at least one metal selected from the group consisting of 160
Hydrocarbons rich in isoparaffins and gasoline fractions are synthesized by contacting with synthesis gas at temperatures above 300°C. The method of this invention will be explained in detail below.

[Function] The reason why the catalyst used in the method of the present invention as described above is excellent in its ability to synthesize hydrocarbons rich in isoparaffins and gasoline fractions is due to the reaction mechanism as described below by Mooji, although the details are unknown. Conceivable. The first catalyst of the mixed catalyst (hereinafter simply referred to as the present catalyst) used in the method of this invention is a conventional Fischer-Dropsch catalyst (hereinafter simply referred to as FT catalyst) that has the ability to synthesize hydrocarbons having 2 or more carbon atoms. be. Regarding FT catalysts, as is well known (for example, Journal of the Japan Petroleum Institute, Vol. 24, No. 4, 233-2)
(p. 39), linear hydrocarbons are mainly synthesized by a mechanism in which linear olefins having 2 to several dozen carbon atoms are once synthesized, and then this linear olefin is hydrogenated on an FT catalyst. . - Zeolite that does not carry any metals easily adsorbs linear olefins as secondary carbonium ions, and also has the ability to polymerize, carbon skeleton isomerize, or decompose the adsorbed carbonium ions at temperatures above 300°C. It is known to have

The catalyst of the present invention differs from the conventional catalyst described above, in that the heavy metal having the ability to dissociate and adsorb hydrogen molecules is supported on zeolite having a pore diameter of 8 Å or more as the second catalyst used in combination with the FT catalyst. I am using it. Therefore, the second catalyst of the present invention, compared to the single-stage reaction catalyst in the conventional method,
The operating temperature of the above-mentioned polymerization and carbon skeleton isomerization of zeolite is lowered to below 300"C, and the ability to supply dissociated activated hydrogen due to the action of supported heavy metals (so-called spillover effect: References, Petroleum Academic Journal Vol. 19, No. 10, pp. 837-844) is added to zeolite, and the dehydrogenolysis effect of carbonium ions contained in zeolite is significantly suppressed.Such a second As a result of the presence of the catalyst in the vicinity of the first catalyst, most of the linear olefins produced by contacting the FT catalyst with the synthesis gas are rapidly adsorbed as secondary carbonium ions on the second catalyst. On this catalyst, a considerable amount of secondary carbonium ions are isomerized to tertiary carbonium ions.At the same time, lower olefins having 2 to 4 carbon atoms or very large carbon atoms are produced by the action of the FT catalyst. When a linear olefin with a number of atoms is adsorbed on a zeolite, a considerable amount thereof is not dehydrogenated and aromatized due to the polymerization or decomposition action of the zeolite, and is converted into a tertiary olefin with a carbon number of 5 to 12. It is polymerized or decomposed isomerized into carbonium ions. On the other hand, a part of the hydrogen in the gas phase is adsorbed to the metal element supported on the zeolite and at the same time is activated by the dissociation effect of the hydrogen contained in this metal. The tertiary carbonium ions generated above and a small amount of remaining secondary carbonium ions are converted into stable paraffins by being supplied with hydrogen anions generated upon activation of hydrogen on the second catalyst. It is thought that the hydrocarbons are converted and separated from the catalyst surface as hydrocarbons rich in isoparaffins and relatively high in gasoline fraction.In the mechanism of action of the catalyst of the present invention, the pore size of the zeolite is smaller than 8. In this case, linear oleolefins produced by the action of the FT catalyst that have a large number of carbon atoms cannot penetrate into the pores of the zeolite, so the effect of the second catalyst becomes completely insufficient. Therefore, the purpose of the present invention cannot be achieved.The action mechanism of the catalyst in the method of the present invention described above is based on a composite catalyst that combines a FT catalyst and a zeolite with a large pore size that does not support heavy metals as seen in conventional methods. Use,
This is quite different from the synthesis of aromatic hydrocarbon-rich products from synthesis gas at temperatures above 350°C. In addition, as shown in Examples and Comparative Examples below, the action mechanism of the catalyst of the present invention is that the conventional mixed catalyst of FT catalyst and zeolite that does not support heavy metals and has a relatively large pore size is
When used at temperatures below 0°C, the ratio of the amount of isoparaffins produced to the amount of normal paraffins produced is approximately 1, whereas in the case of the catalyst of the present invention, this ratio is much larger than 1, resulting in the production of buckwheat. They are also different in that they produce a large amount.

The first catalyst of this invention method is the well-known FT catalyst. That is, it contains iron, cobalt, nickel, ruthenium, molybdenum, etc. as effective metal elements, and a desired compound containing these elements is melted by a well-known method without using a carrier, or a compound containing these elements as a carrier is used. Among catalysts supported on silica gel, titanium oxide, alumina, magnesia, zirconia, etc., abbreviated as molten iron catalysts, precipitated iron catalysts, supported ruthenium catalysts, cobalt catalysts, modified nickel catalysts, etc., at temperatures below 300 °C Any catalyst can be used as long as it has a sufficiently high activity, but for details on the method for producing such a first catalyst, please refer to
For example, R, B, Anderson: Fischer-Dropsch and Related Synthesis (R, B, AnderSOn)
:FiSCher-TrOpSCtl and Re1
ated 5ynthesis: Jon Will
ey & 5ons 1951), so the description will be omitted. However, the first catalyst using zeolite as a carrier has insufficient performance as shown in the comparative example below, and is not suitable as the first catalyst for the method of the present invention.

When cobalt is used as the main active component of the first catalyst, the activity of the first catalyst can be greatly increased by using cobalt with elements such as lanthanum, thorium, chromium, titanium, cerium, etc. as co-catalysts. I can do it.

- In the second catalyst used in the method of this invention, an element or compound that dissociates and activates hydrogen, such as a transition metal element, its sulfide, copper, vanadium, chromium, molybdenum, tungsten, etc. It is preferable that the amount supported is 0.1 to 20% by weight. In this case, the metal is usually supported by impregnating the zeolite in an aqueous solution containing the desired amount of the desired metal, or by adsorbing the metal ions in the aqueous solution to the acid sites in the zeolite by ion exchange using a well-known method. After the adsorbed zeolite has been separated from the aqueous solution, this is achieved, for example, by drying in air at a temperature of 100-140°C and then calcining at a temperature of 400-500°C. Examples of suitable water-soluble salts of metals when the second catalyst is prepared by the above method include ammonium complex salts of platinum chloride as platinum compounds, palladium chloride as palladium compounds, chlorides, nitrates, etc. as compounds of other elements. can be mentioned. In addition, a second material in which the metal sulfide is supported on zeolite
The catalyst can be easily produced by subjecting the metal-supported zeolite described above to the well-known sulfidation treatment method using hydrogen sulfide. Further, as the zeolite used for the second catalyst, it is preferable to use a zeolite having a pore diameter of 88 or more. The reason for this is that, as mentioned above, linear olefins with various numbers of carbon atoms produced by the F'T catalyst and isoparaffins with a relatively large molecular diameter and a medium number of carbon atoms produced on the second catalyst are This is because a pore diameter of at least 8 mm is required in order to freely reach the active site of the second catalyst through the pores of the catalyst, or to leave the active site of the second catalyst into the gas phase. be. It has been found that zeolites with pore sizes of 8 to 13 pores are effective for the second catalyst of the present invention, and it is assumed that there is a suitable upper limit for the pore size of zeolites larger than 13 pores. Since there is currently no zeolite with a pore size larger than 13, it is not possible to specify the upper limit of this value. Zeolites with such pore diameters are usually Y type, L type, X type, or dealuminated Y type (DAY type).
There is something called.

In order for the above mechanism of action to function effectively, the particles of both the first and second catalysts in the method of this invention must be located relatively close to each other. Therefore, in the usual method of the present invention, both the first and second catalysts prepared by the above method are prepared from the beginning in the form of granules each having an appropriate particle size, or each of the two catalysts is
The product is finely pulverized so as to pass through a Tyler sieve of 0 mesh, and the two components in the form of granules are evenly mixed as they are, preferably the finely pulverized components are mixed well, and the desired size is obtained. For example, diameter 3~5TIIT11 length 5~10
It is press-molded into a cylindrical shape and is ready for use. The mixing ratio of the first catalyst and the second catalyst during this mixing is 3:1 to 3:1.
1:5 is good. If the blending ratio is outside this range, the performance of the catalyst of the present invention will not be fully exhibited. Further, when the catalyst of the present invention prepared as described above is brought into contact with synthesis gas to synthesize hydrocarbons, it is necessary to select a temperature of 160°C or more and 300°C or less, preferably 170'C or more and 250°C or less. There is. The contact temperature between this invention catalyst and synthesis gas is 16
When the temperature is below 0, the ability of the first catalyst to synthesize linear olefins decreases, and on the other hand, when the temperature is above 300°C, the mechanism of action of the second catalyst changes as described above, and aromatic hydrocarbons or Large amounts of carbon and its analogues are produced and in both cases it is unsuitable for the synthesis of hydrocarbons rich in isoparaffins and rich in gasoline fractions. In the method of the present invention,
Preferred conditions other than the temperature when the catalyst and gas are brought into contact include a H2/Co molar ratio in the synthesis gas of 4 to 0°5, a pressure of atmospheric pressure to 40 ka/c#G, and a space velocity of 10.
Although a range of 0 to 200001/&r can be mentioned, the method of the present invention is not limited to a range of conditions other than such temperature.

[Example 1] In this example, cobalt and lanthanum were supported on silica gel (hereinafter referred to as A) as the first catalyst,
Three types of catalysts, molten iron catalyst (hereinafter referred to as B) and ruthenium supported on titanium oxide (hereinafter referred to as C), were
Copper is supported on DAY type zeolite as a catalyst (
(hereinafter referred to as "F"), copper and palladium supported on zeolite DAY (hereinafter referred to as "E"), palladium supported on zeolite DAY (hereinafter referred to as "F"), and platinum supported on zeolite DAY (hereinafter referred to as "F"). A hydrocarbon synthesis test was carried out using four types (hereinafter referred to as G) in combination as shown in Table 1.

Manufacture of the first catalyst Corresponding to the above first catalysts A and C, 10
A mixed aqueous solution of cobalt nitrate and lanthanum nitrate containing 3 gr of cobalt and 3 gr of lanthanum, and an aqueous solution of ruthenium chloride containing 2 ar of ruthenium as the pure metal, respectively. Prepare. A mixed aqueous solution of cobalt nitrate and lanthanum nitrate was prepared separately.
100 gr of dry silica gel of 40 mesh was impregnated at room temperature, an aqueous solution of ruthenium nitrate was impregnated with 100 qr of titanium oxide grains of the same particle size prepared separately, each impregnated product was dried in air at 120 ° C for 24 hours, and further 45" After firing for 3 hours in air at 100
The first catalysts A and C were ground to completely pass through a mesh sieve. Al,:S! The weight ratio of Oz, cobalt and lanthanum is 100:10:3, and the weight ratio of T i 02 and ruthenium in C is 100:2.
It is. B is a commercially available molten iron catalyst for ammonia synthesis, and the pure metals include 83.5% iron, 0.5% potassium, 0.2% magnesium, 1.5% aluminum, 0.4% silicon,
1 containing 2.1% calcium and 0.1% or less sodium (both by weight) as oxides,
It was crushed and used in the same manner as I and C.

Preparation of the second catalyst Corresponding to the above second catalysts E, F and G, a cupric nitrate aqueous solution containing 0.32 gr of copper as pure metal, 0.32 gr of copper and 0.05 c+r of palladium were added. A mixed aqueous solution of cupric nitrate and palladium chloride containing 0.
An aqueous solution of palladium chloride containing 0.05 gr of palladium and an aqueous solution of platinum chloride ammonium complex salt containing 0.05 gr of platinum were prepared. In each of these aqueous solutions, fine particles with an average pore diameter of 13 people's Seolide DAY that do not adsorb other heavy metals5. The metals were impregnated with Oar and subjected to ion exchange at room temperature for 3 hours to support these metals on the zeolite. Each zeolite that has been supported is separated from the liquid, dried in air at 120°C for 24 hours, and then calcined in air at 450°C for 3 hours.
Grind the zeolite so that it passes through a 0.00 mesh sieve, and add the above-mentioned second catalyst elements to 100% of the dry zeolite. Second catalysts E, F and G were prepared, each supporting 1.0% of palladium in F and 1.0% of platinum in G (all by weight).

Hydrocarbon synthesis reaction test The first catalyst and second catalyst produced above were thoroughly mixed at a weight ratio of 1:1 to 1:3 as shown in Table 1, and the mixture was mixed to a size of 20 to 40 meshes. Compression molded and 8
A mixed catalyst was prepared. 2 gr of each mixed catalyst was filled into stainless steel reaction tubes with an inner diameter of 6TlrI11, and before the synthesis gas was passed through the reaction tubes, the catalysts were heated to a temperature of 400°C from the outside of the reaction tubes. Hydrogen gas at approximately atmospheric pressure was passed through the inside of the reactor for 14 hours to reduce the catalyst. One day after completion of the reduction, the temperature of the catalyst in the reaction tube was changed to 220°C, 1230'G or 250°C, and the gas flowing in the reaction tube was at a pressure of 5 or 20 ka.
/cTIfG, hydrogen content 66 mol%, CO content 33
The flow rate of mol% synthesis gas is 0.2 mol/each.

switched at the time. All of the gas flowing out of the reaction tube was introduced into a gas chromatograph and analyzed. Analysis of normal paraffins and isoparaffins in the produced hydrocarbons was also carried out using gas chromatography. The results of the analysis show that the reaction rate of carbon monoxide to hydrocarbons (hereinafter simply referred to as the reaction rate) is mol%, and the carbon weight% in methane (hereinafter simply referred to as methane) relative to the total carbon weight in the total hydrocarbons for the generated hydrocarbons. ), carbon weight % in gaseous hydrocarbons having 2 and 3 carbon atoms (hereinafter simply referred to as gas content), carbon weight % in hydrocarbons having 4 to 12 carbon atoms (hereinafter simply referred to as gasoline), and number of carbon atoms. The weight ratio of isoparaffin to normal paraffin weight (hereinafter simply referred to as i/n) for hydrocarbons of 4.5 and 6 was calculated.

The calculation results are shown in Table 1.

[Comparative Example] Next, as a comparative example, A of Example was used as the first catalyst,
Zeolite DAY (hereinafter simply referred to as H) that does not support heavy metals on the second catalyst, Zeolite Y that also does not support heavy metals (hereinafter simply referred to as ■), and Zeolite ZSM-5 that similarly does not support heavy metals (hereinafter simply referred to as J ), fused silica (hereinafter simply referred to as K) are used in combination, and instead of using a mixture of the first catalyst and the second catalyst in the method of the present invention, the method is similar to the method for producing the second catalyst in the example. 10 parts by weight of cobalt as a pure metal was supported on 100 parts by weight of zeolite Y (hereinafter simply referred to as L), and 10 parts by weight of cobalt was supported as a pure metal on 100 parts by weight of zeolite ZSM-5. (hereinafter simply referred to as M) were used individually as catalysts. Table 2 shows the calculation results similar to those in the example.

"Effects of the Invention" As is clear from the above description and examples, the method of the present invention is capable of producing a gasoline rich in isoparaffins and having a high octane number through a one-step reaction from synthesis gas containing carbon oxide and hydrogen. It is an extremely excellent method for producing hydrocarbons. Further, as mentioned above, the catalyst used in the method of the present invention has a small amount of carbon deposited, and the deterioration of catalyst performance due to carbon deposition is small.

Claims (2)

[Claims] (1) Contains at least one element selected from the group consisting of cobalt, iron, ruthenium and nickel,
Iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium, platinum, The mixed catalyst with the second catalyst supporting at least one element selected from the group consisting of copper, vanadium, chromium, molybdenum and tungsden is heated at 160°C or higher at 30°C.
1. A method for producing isoparaffin-rich hydrocarbons, which comprises contacting with a mixed gas containing carbon monoxide and hydrogen at a temperature below 0°C. (2) The method according to claim 1, wherein in the first catalyst containing cobalt, at least one element selected from the group consisting of lanthanum, thorium, titanium, chromium, and cerium is used together with cobalt.