CN1055282C - Catalytic hydrogenation process of industrial C5 fraction to produce pentane - Google Patents

Abstract

The invention relates to a method for producing pentane by catalytic hydrogenation using industrial carbon five fractions as raw materials. The catalytic cracking process of petroleum hydrocarbons or the by-product of the cracking process of petroleum hydrocarbons to produce ethylene-industrial carbon five fractions are a mixture of unsaturated components and saturated components, most of which are non-linear unsaturated carbon five groups share. The method of the present invention is to directly use the industrial C5 fraction as a raw material, and under selected reaction conditions, in the presence of a hydrogenation catalyst, carry out catalytic hydrogenation reaction to the unsaturated components therein, thereby preparing C5 alkyl. Adopting the method of the present invention has very obvious good effects on the new approach of developing industrial C5 fractions, rational utilization of C5 fractions, and optimization of resource allocation.

Description

Method for producing pentane by catalytic hydrogenation of industrial carbon five fractions

The present invention relates to the method for producing pentane through catalytic hydrogenation of industrial carbon five fractions, in particular, the method for producing pentane through catalytic hydrogenation of industrial carbon five fractions.

Pentane is a chemical raw material, which can be used as a basic raw material for solvents, foaming agents and other chemical products. Pentane is usually obtained from the straight run process and hydrocracking process of petroleum hydrocarbons, and a small amount is obtained by hydrogenation of the purified C5 fraction. With the development of petrochemical industry, especially the successive commissioning of ethylene plants, the resources of industrial carbon five fractions are also increasing year by year. At present, there are two main forms of development and utilization of industrial C5 fractions: one is to use industrial C5 fractions after separation, and the other is to directly utilize industrial C5 fractions without separation.

The utilization of industrial carbon five fractions after separation is mainly to separate the diolefin components and use them as chemical raw materials. The remainder can be used in the production of alkylate and tert-amyl methyl ether (TAME). However, since the industrial C5 fraction is composed of a variety of compounds with similar boiling points, not only the components are complex and there are many isomers, but also azeotropes of binary or ternary components may be formed, so the separation is more difficult.

The C5 fraction is used directly without separation, and is mainly used in the production of petroleum resin, tert-amyl methyl ether (TAME) and other fields. There is no literature report on the production of pentane by catalytic hydrogenation using industrial carbon five fractions as raw materials.

The object of the present invention is to provide a kind of utilization industrial carbon five cuts, especially utilize the industrial carbon five cuts without separation as raw material, the method for producing pentane through catalytic hydrogenation.

The method for producing pentane of the present invention is accomplished as follows.

Industrial C5 fractions mainly come from straight run, hydrocracking, catalytic cracking and steam cracking of petroleum hydrocarbons. In addition to the industrial carbon five fractions produced in the straight run and hydrocracking processes whose main component is pentane, the industrial carbon five fractions produced in other processes are a mixture of unsaturated components and saturated components, most of which It is a non-linear unsaturated carbon five.

The method of the present invention is to directly use the industrial C-penta fraction as a raw material, and under selected reaction conditions and in the presence of a catalyst, pentane is produced by catalytically hydrogenating the unsaturated components therein. The industrial C5 fraction comes from the catalytic cracking process of petroleum hydrocarbons or by-products in the process of cracking petroleum hydrocarbons to produce ethylene. Among them, it may be a mixture rich in monoolefins, or a mixture rich in monoolefins and diolefins. It may also be a raffinate mixture after extraction of diolefins.

The reaction temperature of the catalytic hydrogenation reaction is 60-200°C, preferably in the temperature range of 90-150°C. When the diolefin content in the reaction raw material is higher, then increasing the reaction temperature is beneficial to the reaction. The reaction pressure is 0.05-5MPa, increasing the pressure is beneficial to the reaction, but considering the actual comprehensive effect, the reaction pressure is preferably 0.2-1.0MPa. The ratio of raw materials is based on the molar ratio of hydrogen to industrial carbon five fractions, generally 0.5-10, but preferably 2-5. When the diolefin content in the feedstock is high, increasing the molar ratio of hydrogen to C5 fraction is beneficial to the reaction. The liquid hourly space velocity of the C5 fraction is usually 0.3-9hr ^-1 , preferably 0.5-2hr ^-1 . When the diolefin content in the raw material is relatively high, it is beneficial to the progress of the reaction to appropriately reduce the liquid hourly space velocity.

The catalyst used in the catalytic hydrogenation reaction is a common hydrogenation catalyst, and a noble metal supported catalyst or a non-precious metal catalyst can be used.

The precious metal supported catalyst can be expressed as: A/C.

A: Represents metal elements palladium, platinum, ruthenium, rhodium or their mixtures, wherein palladium and platinum are preferred metal elements. The content is generally 0.01-15%, and the preferred content range is 0.03-10%.

C: represents a support, such as alumina, silica or a mixture thereof, or activated carbon, among which alumina and activated carbon are preferred supports.

The non-precious metal type catalyst can be expressed as: B _X ·Ni _Y /C ₁ .

B: Represents metal elements copper, cobalt, chromium, iron, molybdenum, aluminum, silver or their mixtures, among which copper and cobalt are preferred elements.

C ₁ : represents a carrier, such as diatomaceous earth, aluminum oxide, silicon oxide, activated carbon or a mixture of aluminum oxide and silicon oxide, among which diatomaceous earth and aluminum oxide are preferred carriers. Or C ₁ for blank.

The content of the metal element component accounts for 10-50% of the weight of the whole catalyst. In the formula, X is 0-2, and Y is 1-12.

The above-mentioned catalysts can be prepared by usual catalyst production methods. Such as the noble metal supported catalyst Pd/Al ₂ O ₃ , the Al ₂ O ₃ pellets can be impregnated with an appropriate amount of palladium chloride solution, dried and reduced before use. For non-precious metal catalyst Ni-Cu/diatomite, fine powdered diatomite can be added to the corresponding nitrate solution, then heated and stirred to form a uniform slurry, which is then filtered, dried, and shaped. Oxygen reduction.

The types and contents of mono-olefins and di-olefins contained in industrial carbon five fractions vary greatly depending on their sources, but the chemical properties of unsaturated olefins are different. Due to the relatively active chemical properties of carbon pentaene bonds, under the action of hydrogenation catalysts, catalytic hydrogenation reactions are likely to occur, thereby turning unsaturated bonds into saturated bonds. The chemical reaction formula is as follows.

1,

like:

2,

like:

The hydrogenation reaction is completed in a fixed-bed reactor in a gas-solid or gas-liquid-solid phase, in a continuous or batch manner. Under the selected process conditions, the industrial C5 fraction of the reaction material is mixed with hydrogen and enters the heater, and the reaction material at the outlet of the heater enters the catalytic bed in the form of gas phase or gas-liquid mixture, and the product after the hydrogenation reaction passes through After the usual condensation and separation, the pentane product is obtained.

By adopting the method for producing pentane provided by the present invention, after the catalytic hydrogenation reaction of the industrial carbon five fractions, the single-pass conversion rate of carbon pentaolefins in it can reach more than 83%, and the single-pass conversion rate of diolefins can reach more than 86%. And the yield of pentane can reach more than 89%. Therefore, the method provided by the present invention is undoubtedly a very valuable method in the technical field of producing pentane by catalytic hydrogenation of raw materials using industrial carbon five fractions.

The following examples are used to illustrate the method of the present invention in detail. Example 1:

The industrial C5 fraction is metered and mixed with the corresponding amount of hydrogen. After passing through the reaction material heater, it enters the fixed bed reactor with condensate jacket. After the reaction product is condensed and separated, the liquid phase product is collected and analyzed and checked by a gas chromatograph.

Raw materials: hydrogen: hydrogen in ordinary steel cylinders, with a purity greater than 99.5%; industrial carbon five fractions: obtained from by-products in the process of cracking naphtha to produce ethylene, of which

Most of the diolefins in the raffinate mixture contain

 Concentration 90%, alkanes 8.5%, remaining diolefins 1.5%;

catalyst:

Noble metal supported catalyst Pd/Al ₂ O ₃ , Pd content 0.03%, Φ4×4 columnar body, reaction load 100ml, used after hydrogen reduction at 250°C.

Reaction conditions: temperature: 90°C; pressure: 0.1MPa; hydrogen/oil molar ratio: 2; liquid hourly space velocity: 1.6hr ^-1 .

Reaction result: olefin conversion: 96%; pentane yield: 98%: n-pentane accounts for 70% of the total pentane. Example 2:

Raw material: Industrial C5 Fraction: It is obtained from the by-products in the process of producing ethylene from naphtha cracking, regardless of

Separation of diolefins, its composition is monoolefin content 49.5%,

 Dienes 45%, Alkanes 5.5%.

Reaction conditions: temperature: 105°C; pressure: 0.3MPa; hydrogen/oil molar ratio: 5; liquid hourly space velocity: 0.8hr ^-1 .

All the other are identical with embodiment 1.

Reaction results: mono-olefin conversion: 89%; di-olefin conversion: 93%; pentane yield: 91%; n-pentane accounts for 68% of the total pentane. Example 3:

catalyst:

Noble metal supported catalyst Pt/Al ₂ O ₃ , Pt content 0.4%, Φ3 small balls.

Preparation steps:

1. Heat spherical alumina with a diameter of Φ3 and a specific surface area of 200m ² /g to 200°C, and weigh 200g after cooling.

2. Take 50g of it and immerse it in water, then use filter paper to dry the water on the outer surface, and weigh 69g.

3. Prepare 57g of 5% sodium carbonate solution, immerse the remaining 150g of alumina in step 1, then heat to 200°C and keep it for 2 hours.

4. Prepare 57 g of 1.3% chloroplatinic acid solution, immerse the alumina in step 3 in it, then dry at 150° C., and bake at 300° C. for 2 hours.

5. Use distilled water to remove chloride ions, and then dry at 150°C.

6. Take 100ml of the catalyst prepared in step 5 and activate it in a hydrogen flow at 300°C.

All the other are identical with embodiment 1.

Reaction results: olefin conversion: 95%; pentane yield: 93%; n-pentane accounts for 67% of the total pentane. Example 4:

Catalyst: non-precious metal catalyst Ni-Cu/diatomaceous earth, the atomic ratio of nickel to copper is 9, the total amount of nickel and copper accounts for 40% of the whole catalyst, and the particle size is small particles between 5 and 10 mesh.

Its preparation process is as follows:

A nitrate solution 21 containing 183 g of nickel and 21 g of copper was prepared, 500 g of diatomaceous earth was put into it, stirred and heated to 70°C. Then slowly feed 10% sodium bicarbonate until the pH value of the slurry reaches 8. Stirring was then continued for 5 hours, followed by filtration. The filter cake was dried at 150°C, crushed and calcined at 500°C for 6 hours. Then tablet, pulverize and shape into small particles between 5 and 10 meshes. Reduce with hydrogen at 400°C before use.

Reaction conditions; temperature: 130°C; pressure: 0.6MPa; hydrogen/oil molar ratio: 7; liquid hourly space velocity: 0.3hr ^-1 .

All the other are identical with embodiment 1.

Reaction result: monoolefin conversion: 87% : pentane yield: 90%.

Claims (4)

1. A method for producing pentane, which is characterized in that the industrial C5 fraction is used as a raw material, and in the presence of a hydrogenation catalyst, the reaction temperature is 60-200°C, the reaction pressure is 0.05-5MPa, hydrogen/oil Under the condition that the molar ratio is 0.5-10 and the liquid hourly space velocity of the carbon-penta fraction is 0.3-9hr ^-1 , olefins in the industrial carbon-penta fraction and hydrogen are subjected to catalytic hydrogenation reaction to produce pentane. 2, according to the described pentane manufacturing method of claim 1, it is characterized in that used industrial carbon five cuts come from the catalytic cracking process of petroleum hydrocarbon or the by-product in the cracking ethylene process of petroleum hydrocarbon, wherein can be rich in mono A mixture of olefins, a mixture rich in mono-olefins and di-olefins, or a raffinate mixture after extraction of di-olefins. 3. The method for producing pentane according to claim 1, characterized in that the hydrogenation catalyst has the general formula A/C, wherein: A is palladium, platinum, ruthenium or rhodium, or a mixture of two or more thereof, C is aluminum oxide or silicon oxide or a mixture thereof, or active carbon, and the content of A is 0.01-15%. 4. The method for producing pentane according to claim 1, characterized in that the hydrogenation catalyst has the general formula B _x .Ni _y /C ₁ , wherein: B is copper, cobalt, chromium, iron, molybdenum, aluminum or silver, or a mixture of two or more thereof, C is alumina or silica or a mixture thereof, or activated carbon, x=0～2, y=1～12, The content of the metal element component is 10-50% of the weight of the catalyst.