TW201707788A - A hydrocarbon conversion catalyst - Google Patents

Abstract

The present invention relates to a catalyst in oxidic form comprising metals M1, M2, M3 and M4, wherein: M1 is selected from Si, Al, Zr, and mixtures thereof; M2 is selected from Pt, Cr, and mixtures thereof; M3 is selected from W, Mo, Re, and mixtures thereof; and M4 is selected from Sn, K, Y, Yb and mixtures thereof; wherein mass fraction of M1 is in the range of 0.1 to 0.8; mass fraction of M2 is in the range of 0.001 to 0.2; mass fraction of M3 is in the range of 0.001 to 0.2; mass fraction of M4 is in the range of 0.0001 to 0.2; and mass fraction of oxygen is in the range of 0.1 to 0.8.

Description

Hydrocarbon conversion catalyst

This invention relates to a catalyst for the conversion of hydrocarbons. More specifically, the invention relates to a catalyst for converting a hydrocarbon feed to a less saturated hydrocarbon product.

Olefins, especially light olefins including ethylene and propylene, are important hydrocarbon products. They can be used to prepare a wide variety of end products including ethylene oxide, propylene oxide, ethylbenzene, acetone, phenol, polyethylene, polypropylene, other polymers, and other petrochemical products. Even if prices fluctuate over time, their demand in the industry continues to grow.

A variety of methods have been used to produce olefins in response to industry needs. However, it is generally more economically attractive to produce olefins from lower value feeds such as paraffinic hydrocarbons. The traditional method of converting paraffinic hydrocarbons to olefins is thermal cracking; it is a highly energy consuming process and it is difficult to adjust and control product selectivity. Catalytic cracking is a relatively late development method; using a suitable catalytic material, generally a zeolite based material, hydrocarbon cracking can occur in less severe operating environments.

Several improvements have been studied and disclosed for several catalytic cracking. For example, US 8,933,286 B2 discloses a catalytic cracking process using a nickel modified zeolite catalyst. The process can be operated under milder operating conditions. However, a large number of by-products, including methane and C5+ hydrocarbons, are observed and are not stable with respect to the catalyst. Qualitative description.

US 8,198,498 B2 discloses a metal oxide coated carbon nanotube catalyst for use in a hydrocarbon cracking process. The process is still highly energy intensive because in order to achieve improved yields of the desired olefin product, the process must be carried out at relatively high temperatures, and steam is preferably added to the feed stream.

It is an object of the present invention to provide a catalyst for hydrocarbon conversion that overcomes the deficiencies of the prior art. In particular, it is an object of the present invention to provide a catalyst which converts a hydrocarbon feed to a less saturated hydrocarbon product which can be operated under mild conditions, especially at relatively low temperatures, but which can be produced with high selectivity. A lesser degree of hydrocarbon product to obtain the desired product.

The present invention provides a catalyst in the form of an oxide and comprising metals M1, M2, M3, and M4, wherein: M1 is selected from the group consisting of Si, Al, Zr, and mixtures thereof; and M2 is selected from the group consisting of Pt, Cr, and a mixture; M3 is selected from the group consisting of W, Mo, Re, and mixtures thereof; and M4 is selected from the group consisting of Sn, K, Y, Yb, and mixtures thereof; wherein the mass fraction of M1 is 0.1 to 0.8; the mass fraction of M2 is 0.001 to 0.2; the mass fraction of M3 is 0.001 to 0.2; the mass fraction of M4 is 0.0001 to 0.2; and the mass fraction of oxygen is 0.1 to 0.8.

The catalyst of the invention can be highly selective under relatively mild conditions The hydrocarbon feed is converted to an olefin product.

In one embodiment, the catalyst of the present invention is a hydrocarbon conversion catalyst, that is, a catalyst for a hydrocarbon conversion process, which is a multimetal composition comprising the following components: M1 is selected from the group consisting of Si, Al, Zr, and mixtures thereof; M2 is selected from the group consisting of Pt, Cr, and mixtures thereof, preferably Pt; M3 is selected from the group consisting of W, Mo, Re, and mixtures thereof, preferably W; and M4 is selected from the group consisting of Sn, K, Y, Yb, and mixtures thereof. Wherein the mass fraction of M1 is from 0.1 to 0.8, preferably from 0.2 to 0.6; the mass fraction of M2 is from 0.001 to 0.2, preferably from 0.0015 to 0.15, more preferably from 0.005 to 0.1, and the mass fraction of M3 is from 0.001 to 0.2. Preferably, it is 0.005 to 0.15, more preferably 0.01 to 0.1; the mass fraction of M4 is 0.0001 to 0.2, preferably 0.00015 to 0.03, more preferably 0.005 to 0.02; and the mass fraction of oxygen is 0.1 to 0.8, preferably 0.2 to 0.5. .

Here, the term "mass fraction" is relative to the total mass (weight) of the catalyst of the present invention.

In one embodiment, the catalyst preferably has the chemical formula M1M2M3M4O.

In another embodiment, the catalyst of the present invention further comprises M5 (ie, a catalyst having the formula M1M2M3M4M5O) wherein M5 is selected from the group consisting of Mg, Ca, Mn, Fe, Co, Ni, Cu, and mixtures thereof, preferably Mg, Ca, and mixtures thereof; and mass fraction of M5 It is 0.005 to 0.1, preferably 0.01 to 0.09.

Each of the foregoing embodiments, with respect to the inclusion of a preferred metal in the catalyst or for a particular amount of each component, achieves a preferred catalyst, i.e., a catalyst that exhibits preferred selectivity and can be operated at lower temperatures. Each of the foregoing embodiments is suitable for improvement as a catalyst alone. However, one or more combinations of the foregoing preferred metals or preferred amounts thereof may synergistically improve the catalyst.

The catalyst of the present invention can be obtained by mixing all of the elements M1 to M5 before the precursor, followed by appropriate heat treatment to obtain the desired multimetal composition. The element precursor is a starting compound containing the desired element which can be converted to the desired form of the element by a suitable heat treatment in the final catalyst, preferably an oxide. For example, the precursors of M1 to M5 may include oxides, halides, alkoxides, nitrates, carbonates, formates, oxalates, amines, or hydroxides of the elements.

The mixing of the element precursors can be carried out in a dry or wet manner. The element precursors are conveniently provided in powder form when they are mixed in a dry form. The powder of the element precursor can be simply mixed by physical mixing in the mixer. The mixture of element precursors is then preferably sintered by suitable heat treatment to obtain the final hydrocarbon conversion catalyst. When they are mixed in a wet form, the element precursors may be provided in the form of a solution and/or suspension. The solution of the element precursor and/or the suspension mixture is then dried to remove the solvent. Thereafter, the dried mixture is preferably sintered by a suitable heat treatment to obtain a final catalyst. Or, some element precursors are dry A portion of the element precursor is provided in a wet form. Dry and wet element precursors can be combined by conventional methods, including impregnation, initial wetting, ion exchange, or other methods known in the art. The obtained mixture is preferably sintered by a suitable heat treatment to obtain a final catalyst. Suitable heat treatment involves the selected atmosphere and the selected temperature sufficient to remove and/or convert at least a portion of the elemental precursor to the desired form of the corresponding element in the final catalyst. It is especially preferred that the element be in the form of an oxide in the final catalyst. The selected atmosphere may include an oxidizing atmosphere, a reducing atmosphere, and an inert atmosphere. In a preferred embodiment, the prepared catalyst powder is sintered in air at a temperature of 300 ° C to 800 ° C for 1 to 24 hours, and even more preferably at a temperature of 400 ° C to 600 ° C for 2 to 10 hours. sintering.

In another embodiment, the preparation of the catalyst according to the invention may further involve forming the catalyst powder into a shape suitable for use in a commercial reactor. Shapes suitable for use in commercial reactors can include ingots, extrudates, spheres, and the like. Further sufficient bonding material can be added to the catalyst composition to form the catalyst smoothly. Providing the catalyst in a specific shape makes its application easier.

The catalyst of the present invention can be used in a hydrocarbon conversion process wherein a hydrocarbon feed stream is contacted with a catalyst of the invention. To produce an olefin product, the hydrocarbon feed stream advantageously comprises a paraffinic hydrocarbon. In a preferred embodiment, the hydrocarbon feed stream comprises a paraffinic hydrocarbon having from 2 to 5 carbon atoms. In a more specific embodiment, the hydrocarbon feed stream comprises a paraffinic hydrocarbon selected from the group consisting of ethane, propane, butane, pentane, and mixtures thereof, preferably propane, butane, and mixtures thereof.

Further, for the purpose of producing an olefin, the hydrocarbon conversion process is carried out at a temperature of from 200 ° C to 700 ° C, preferably from 300 ° C to 600 ° C, and even more preferably from 350 ° C to 550 ° C. The catalyst of the present invention can drive a hydrocarbon conversion process at a preferred temperature as described above, which is lower than processes known in the art. In another embodiment, the process is carried out at a pressure of from 0.01 to 10 bar gauge, preferably from 0.05 to 5 bar gauge. The desired contact time to obtain the desired olefin product yield is related to several factors, such as operating temperature, operating pressure, and catalyst activity. In one embodiment, the process is carried out at a weight hourly space velocity (WHSV) of from 0.01 to 20 hours ^-1 , preferably from 0.05 to 5 hours ^-1 . The process can be carried out in batch or continuous mode. For commercial scale, it is preferred to have the process operate continuously. Continuous operation can be carried out in fixed bed, fluidized bed, or other techniques known in the art, with a fixed bed being generally preferred.

The catalyst can be selectively pretreated prior to contact with the hydrocarbon feed stream. The pretreatment conditions can include contacting the catalyst with an inert gas, an oxidizing gas, a reducing gas, a hydrocarbon (preferably a C2-C6 aliphatic hydrocarbon), and any combination thereof. This pretreatment can be divided into several steps, in which different conditions and atmospheres can be employed for each step. It is generally preferred to carry out the pretreatment at a heating temperature, preferably from 200 ° C to 700 ° C, more preferably from 300 ° C to 600 ° C, even more preferably from 350 ° C to 550 ° C.

Certain toxic materials, heavy hydrocarbons, and coal char may deposit on the surface of the catalyst after contact with the hydrocarbon feed stream in an operating environment. This usually affects the activity of the catalyst, causing it to gradually decrease over time. The used catalyst can be suitably regenerated to recover at least a portion of the activity. In one embodiment, the hydrocarbon conversion process comprises a regeneration step wherein the regeneration step comprises contacting the hydrocarbon conversion catalyst with an oxidant at elevated temperatures. The regeneration step should be carefully controlled to avoid overheating and destroy the structure of the catalyst. In one embodiment, the regeneration step is carried out at a temperature of from 200 ° C to 700 ° C, preferably from 300 ° C to 600 ° C. Other known regeneration techniques can be used without limitation.

The catalyst according to the present invention can convert the light paraffin hydrocarbon feed to light olefins including ethylene, propylene, and butene with high selectivity. Manufacturing only a significant amount of low Value by-products such as methane and heavy hydrocarbons.

Embodiments and benefits of the present invention are illustrated by the following examples.

Example

Example 1 (Comparative Example)

A zeolite catalyst containing 0.95 parts by mass of Si and 0.05 parts by mass of Al was contacted with propane at 475 ° C, 1 bar gauge, and WHSV of 0.12 hr ^-1 . The results of the 3 hour and 8 hour reaction product streams are shown in Table 1.

Example 2 (Comparative Example)

The catalyst containing 0.5 mass fraction Al, 0.45 mass fraction O, and 0.05 mass fraction Pt was contacted with propane at 475 ° C, 1 bar gauge, and WHSV of 0.12 hr ^-1 . The results of the 3 hour and 8 hour reaction product streams are shown in Table 1.

Example 3 (Comparative Example)

The catalyst containing 0.245 mass fraction Si, 0.215 mass fraction Al, 0.045 mass fraction W, 0.475 mass fraction O, and 0.02 mass fraction Pt at 475 ° C, 1 bar gauge, and 0.12 h ^-1 WHSV Contact with propane. The results of the 3 hour and 8 hour reaction product streams are shown in Table 1.

Example 4 (present invention)

Catalyst containing 0.26 mass fraction Si, 0.21 mass fraction Al, 0.045 mass fraction W, 0.455 mass fraction O, 0.02 mass fraction Pt, and 0.01 mass fraction K at 475 ° C, 1 bar gauge, and 0.12 contacting propane with a WHSV hr ^-1. The results of the 3 hour and 8 hour reaction product streams are shown in Table 1.

Example 5 (present invention)

Catalyst containing 0.26 mass fraction Si, 0.21 mass fraction Al, 0.045 mass fraction W, 0.455 mass fraction O, 0.02 mass fraction Pt, and 0.01 mass fraction Sn at 475 ° C, 1 bar gauge, and 0.12 contacting propane with a WHSV hr ^-1. The results of the 3 hour and 8 hour reaction product streams are shown in Table 1.

Example 6 (present invention)

It contains 0.306 mass fraction Si, 0.012 mass fraction Al, 0.031 mass fraction Mg, 0.044 mass fraction W, 0.387 mass fraction O, 0.189 mass fraction Zr, 0.02 mass fraction Pt, and 0.011 mass fraction Y. The catalyst was contacted with propane at 475 ° C, 1 bar gauge, and a WHSV of 0.12 hours ^-1 . The results of the 3 hour and 8 hour reaction product streams are shown in Table 1.

Example 7 (present invention)

Catalyst containing 0.248 mass fraction Si, 0.213 mass fraction Al, 0.031 mass fraction Mg, 0.044 mass fraction W, 0.433 mass fraction O, 0.02 mass fraction Pt, and 0.011 mass fraction K at 475 ° C, 1 Bar gauge pressure, and contact with propane at a WHSV of 0.12 hours ^-1 . The results of the 3 hour and 8 hour reaction product streams are shown in Table 1.

The selectivity of all olefins is calculated from the selectivity of the olefin product including ethylene, propylene, and butene.

It can thus be seen that the use of the catalyst of the invention in the conversion of paraffinic hydrocarbon feeds results in higher selectivity of the total olefin product and the production of less methane and heavy hydrocarbons.

The features disclosed in the foregoing description and the scope of the patent application, whether individually or in any combination, may be employed as a material in various forms.

Claims (10)

a catalyst in the form of an oxide and comprising metals M1, M2, M3, and M4, wherein: M1 is selected from the group consisting of Si, Al, Zr, and mixtures thereof; M2 is selected from the group consisting of Pt, Cr, and mixtures thereof; Is selected from the group consisting of W, Mo, Re, and mixtures thereof; and M4 is selected from the group consisting of Sn, K, Y, Yb, and mixtures thereof; wherein the mass fraction of M1 is 0.1 to 0.8; and the mass fraction of M2 is 0.001 to 0.2. The mass fraction of M3 is 0.001 to 0.2; the mass fraction of M4 is 0.0001 to 0.2; and the mass fraction of oxygen is 0.1 to 0.8. The catalyst of claim 1 wherein M2 is Pt. The catalyst of claim 1 wherein M3 is W. The catalyst of claim 1, wherein the mass fraction of M1 is from 0.2 to 0.6. The catalyst of claim 1, wherein the mass fraction of M2 is from 0.0015 to 0.15. The catalyst of claim 1, wherein the mass fraction of M3 is from 0.005 to 0.15. The catalyst according to claim 1, wherein the mass fraction of M4 is 0.00015 to 0.03. The catalyst of claim 1, wherein the mass fraction of oxygen is from 0.2 to 0.5. The catalyst according to any one of claims 1 to 8, further comprising M5 selected from the group consisting of Mg, Ca, Mn, Fe, Co, Ni, Cu, and mixtures thereof, and the mass fraction of M5 is 0.005 to 0.1. The catalyst of claim 9, wherein the mass fraction of M5 is from 0.01 to 0.09.