CN1326817C - Process for preparing propylene by assimilation of ethylene and butylene on moving bed - Google Patents

Abstract

A method for producing propylene by deproportionation of ethylene and butene on a moving bed. During the process of deproportionation of ethylene and butene to propylene, a part of the catalyst is removed from the reaction zone in a continuous or discontinuous manner for regeneration. After regeneration-activation The catalyst is transferred to the reaction zone, that is, it is regenerated while reacting, and it goes round and round, and the cycle is carried out. The process provided by the invention can produce propylene with high conversion rate, high selectivity and high stability. Compared with the fixed bed process, under the condition of maintaining the same conversion rate and selectivity as the fixed bed, the stability of the catalyst can be significantly improved, while compared with the fluidized bed/ebullating bed, the mechanical strength of the catalyst, especially the abrasion Index requirements can be greatly reduced.

Description

A kind of method that carries out ethylene and butene reverse disproportionation to produce propylene on moving bed

technical field

The present invention relates to a method for producing propylene by deproportionation of ethylene and butene, in particular a method for producing propylene by deproportionation of ethylene and butene on a moving bed. The process provided by the invention can achieve high conversion rate, high selectivity and Propylene is produced with high stability.

Background technique

Propylene is one of the important basic raw materials for the development of petrochemical industry, and it is also the petrochemical product with the fastest growing demand in the world. The demand for propylene in the world has increased from 18 million tons in 1980 to nearly 50 million tons in 2000, and it is expected to reach 50 million tons in 2010. 75 million tons. The production of propylene by reacting ethylene and butene is one of the methods to increase the output of propylene. Since the supply of butene exceeds the demand at present, especially butene-2 lacks effective utilization methods, the reaction process of ethylene, propylene and propylene can be reasonably adjusted according to local conditions. Product layout of butene. In addition, the heavy oil catalytic cracking products include some crude ethylene containing methane, ethane and a small amount of hydrogen, which can be reacted with butene to produce propylene, which can not only increase the output of propylene, but also reduce the energy consumption of cryogenic separation, and by Thermodynamic calculations show that the reaction process is more favorable than the disproportionation of propylene. This is a practical and novel process, and its successful development can produce significant economic and social benefits.

US patents (USP5,877,365, USP6,624,338) reported the conversion of _C4 cuts into polyisobutylene and propylene. This process includes the following three steps: (1) isomerization of butene-1 to butene-2; (2) polymerization of isobutene into polyisobutene; (3) deproportionation of butene-2 and ethylene to produce propylene. Butene-2 and ethylene reverse disproportionation to produce propylene. The catalyst used is the oxide of rhenium (0.01-20wt%) loaded on the mixed oxide, and the mixed oxide includes at least 75% alumina, and the others are silicon aluminum oxide, molecular sieve and At least one of oxides of cesium, niobium and tantalum. The reaction temperature is between 0-200°C, and the pressure is higher than the saturated vapor pressure of the mixed gas at the corresponding reaction temperature.

U.S. Patent (USP5,120,894, USP2003028063) has reported the catalyst of ethylene and butene dedisproportionation to produce propylene, and this catalyst is tungsten oxide supported on silica, and this catalyst is used for the reaction of ethylene and butene dedisproportionation to produce propylene , the operating temperature range is 50-600°C, and the preferred temperature range is 200-400°C.

Chinese patent (CN1033246A) has reported the catalyst that is suitable for C ₆ -C ₆₀ monomer olefins to prepare different carbon number olefins by disproportionation reaction, and its main composition is supported molybdenum oxide on the alumina, also contains phosphorus and/or sulfur simultaneously compound.

Above-mentioned patent is all carried out on fixed bed.

Chinese patent (application number is 01130865.6) has reported the catalyzer of ethylene and butylene antiproportionation to produce propylene, and this catalyst is that at least one in molybdenum and/or tungsten and/or rhenium compound is loaded on the molecular sieve carrier, and molecular sieve comprises Y, Beta , SAPO series, ZSM series and MCM series. The reaction is carried out in a fixed bed or fluidized bed reactor, the reaction temperature is 0-300°C; the weight space velocity: 0.01-3h ^-1 ; the ratio of C ₂ H ₄ /C ₄ H ₈ -2 in the reaction raw material gas is 0.2- 4; Reaction pressure 0.1-2.0MPa.

Chinese patent (application number is 02124835.4) has reported the catalyst of ethylene and butene deproportionation to produce propylene, and its composition is A/D, and active component A is at least one in the oxide of molybdenum and/or the oxide of tungsten, Its weight loading is 0.5-20%. The carrier D is alumina or a mixture of alumina and other oxides. Other oxides include one or more of silica, clay, alkaline earth metal oxides, and rare earth metal oxides. kind.

Chinese patent (application number is 200410035035.5) has reported the catalyst of ethylene and butene dedisproportionation to produce propylene reaction, and its composition is AR/D, and active component A is at least one in tungsten, molybdenum and rhenium; Auxiliary agent R is rare earth Metal element; carrier D is a mixture, wherein the main component is molecular sieve (mainly including Y, β, SAPO series, ZSM series and MCM series, the weight content of which is at least 50%). The preparation method of the catalyst is as follows: first, a mixture carrier D with a certain particle size is prepared by a conventional method, then impregnated D with a solution providing rare earth metal elements, dried and calcined at 400-850° C. for a certain period of time, and then the calcined product is provided with molybdenum and Impregnate with a solution of tungsten and/or rhenium, dry and bake at 400-850°C for a certain period of time, and finally treat it with 100% steam at 300-650°C and a weight hourly space velocity of 2-8h ^-1 for 1- 10 hours.

The reactions involved in the above Chinese patents are all carried out in fixed bed or fluidized bed reactors.

Contents of the invention

The object of the invention is to produce propylene by deproportionation of ethylene and butene on a moving bed, and the invention can produce propylene with high conversion rate, high selectivity and high stability. Compared with the fixed bed process, under the condition of maintaining the same conversion rate and selectivity as the fixed bed, the stability of the catalyst can be significantly improved, while compared with the fluidized bed/ebullating bed, the mechanical strength of the catalyst, especially the abrasion Index requirements can be greatly reduced.

The method for producing propylene by dedisproportionation of ethylene and butene on a moving bed provided by the present invention is specifically, during the reaction process of producing propylene by dedisproportionation of ethylene and butene, a part of the catalyst is removed from the reaction zone for regeneration, and the activated catalyst is regenerated The catalyst is then transferred to the reaction zone, that is, it is regenerated while reacting, and it goes round and round, and the cycle is carried out.

In the present invention, the catalyst can be removed from the reaction zone in a continuous or discontinuous manner. The catalyst removal speed is greater than or equal to the critical speed (the critical speed is defined as the removal speed corresponding to the catalyst activity in the reactor being 95% of the initial stable activity value of the catalyst).

The method of the present invention carries out the deproportionation of ethylene and butene to produce propylene on a moving bed, the catalyst is placed in a moving bed reactor, ethylene and butene are the reaction raw materials, the weight space velocity of the raw material gas is 0.01-3h ^-1 , and the temperature is 0-300°C , the pressure is 0.1-6.0Mpa, the molecular ratio of ethylene/butene in the feed gas is 0.2-10;

During the reaction, when the activity of the catalyst is 95% of the initial stable activity, the catalyst is removed from the reactor for regeneration. The regeneration conditions are: temperature 300-600°C, pressure 0.1-6.0Mpa, regeneration gas is air, O ₂ and O ₂ Mixed gas with N ₂ (O ₂ /N ₂ : -50vol%), one or more mixed gases, weight space velocity 1-30h ^-1 , regeneration time 2-15 hours, regenerated-activated The catalyst then enters the reactor to participate in the reaction, and thus circulates.

The catalyst used in the present invention may be one or a mixture of catalysts described in Chinese patents (No. 01130865.6; 02124835.4; 200410035035.5).

The _C4 raw material in the present invention may be butene-2, may be a mixed material with a butene-2 content greater than 50%, or may be butene-1. When butene-1 is used as raw material, butene-1 needs to undergo isomerization reaction first, so as to obtain a mixture of butene-1 and butene-2 which is close to the thermodynamic equilibrium value as the anti-disproportionation raw material. The reaction conditions are: temperature 0-300°C; pressure 0.1-6.0MPa; raw material gas weight space velocity 0.01-3h ^-1 ; ethylene/butene-2 molecular ratio in the reaction raw material gas 0.2-10.

Description of drawings

Fig. 1 is the process flow chart of the present invention for producing propylene from ethylene and butene reverse disproportionation.

Fig. 2 is the relation of the reaction activity of the catalyst of the present invention as a function of time.

Detailed ways

The present invention will be further described below in conjunction with the examples, but the present invention is not limited in any way. For example, the types of raw materials and catalysts used are known technologies, and for the sake of brevity, they are not given in the examples one by one.

Example 1

Figure 1 is a process flow diagram of ethylene and butene deproportionation to propylene moving bed, the catalyst reacts in reactor 1, and the removed catalyst is regenerated and activated in regeneration-activator 2/regeneration-activator 3, and the regeneration activation is good Catalyst samples were transferred to Reactor 1 for reaction.

Prepare the H-70Beta-30Al ₂ O ₃ carrier with a certain particle size by a conventional method (H means that the molecular sieve is H type, 70 and 30 represent the weight percentage of molecular sieve and other components, and the following expressions are similar and will not be described again), Take out 700 grams and vacuum impregnate it with La(NO ₃ ) ₃ solution. The impregnated particles are dried at 100°C for 2 hours and roasted at 550°C for 3 hours. ℃ drying for 2 hours and 550 ℃ calcination for 3 hours to prepare catalyst A, wherein the weight content of La and Mo are 0.5% and 6% respectively.

Example 2

In Example 1, 300 grams of Catalyst A was treated with 100% steam for 2 hours at 400°C and a weight hourly space velocity of 4h ^-1 to obtain the required Catalyst B, wherein the weight contents of La and Mo were 0.5% and 6% respectively .

Example 3

It is 20mm that 80g is packed into the catalyst prepared according to embodiment 1, and high is in the stainless steel moving bed reactor 1 (as Fig. 1) of 300mm, in _N Atmosphere be warming up to 550 ℃ and maintain 1 hour, then under N ₂ atmosphere down to 125°C. Use nitrogen to raise the pressure of the reaction system to 1.0MPa, switch nitrogen to ethylene and butene-2 to carry out the dedisproportionation reaction, keep the weight space velocity of butene-2 at 0.2h ^-1 , and the molecular ratio of ethylene/butene-2 to 2 . Sampling and analysis began 20 minutes after switching. Every 6 hours of reaction, remove 30g of catalyst from the reactor, supplement 30g of regenerated-activated catalyst from the regeneration-activator 3 into the reactor 1, and go round and round, and cycle. The removed catalyst is transferred to regeneration-activator 2 and 3 for regeneration-activation, and the specific conditions are: air, weight space velocity 25h ^-1 , temperature 500°C; pressure 1.0Mpa, time 3 hours, the regenerated-activated sample is left Reserved in the regeneration-activator. The change rule of the reaction activity of catalyst A (indicated by C for convenience) with time in the moving bed reactor is shown in Fig. 2 .

Example 4

It is 20mm that 80g is packed into the catalyst prepared according to embodiment 2, and height is in the stainless steel moving bed reactor (as Fig. 1) of 300mm, in _N The atmosphere is warming up to 550 ℃ and maintains 1 hour, then under _N The atmosphere drops to 125°C. Use nitrogen to raise the pressure of the reaction system to 1.0MPa, switch nitrogen to ethylene and butene-2 to carry out the dedisproportionation reaction, keep the weight space velocity of butene-2 at 0.2h ^-1 , and the molecular ratio of ethylene/butene-2 to 2 . Sampling and analysis began 20 minutes after switching. After reacting 2 hours, begin to remove catalyst with the speed of 5 gram/hour from reactor, replenish regeneration-activation good catalyst to enter in reactor with identical speed (5 gram/hour) by regeneration-activator 3, go round and begin again, Cycle through. The removed catalyst is transferred to the regeneration-activator 2 for regeneration-activation, and the specific conditions are: a mixture of O ₂ and N ₂ (O ₂ /N ₂ : 50vol%), a weight space velocity of 5h ^-1 , and a temperature of 550°C; The pressure is 1.0Mpa, and the time is 6 hours. The regenerated-activated sample is transferred to the regenerated-activator 3 for later use. The change rule of the reaction activity of catalyst B (for convenience, represented by D) with time in the moving bed reactor is shown in Fig. 2 .

Comparative example 1

The catalyst (A or B) that 80g prepares according to embodiment 1 or 2 is loaded into inner diameter and _is 20mm, is high in the stainless steel fixed-bed reactor of 300mm, in N Atmosphere be warming up to 550 ℃ and maintain 1 hour, then in _N2 atmosphere down to 125 °C. Use nitrogen to raise the pressure of the reaction system to 1.0MPa, switch nitrogen to ethylene and butene-2 to carry out the dedisproportionation reaction, keep the weight space velocity of butene-2 at 0.2h ^-1 , and the molecular ratio of ethylene/butene-2 to 2 . Sampling and analysis began 20 minutes after switching. The change of the reactivity of catalysts A and B in the fixed bed reactor with time is shown in Fig. 2 .

It can be seen from Figure 2 that the catalyst in the moving bed reactor has greatly improved the stability of the sample on the basis of ensuring the activity of the procatalyst.

Claims (3)

1. method of on moving-bed, carrying out ethene and butene inverse disproportionation system propylene, catalyzer places in the moving-burden bed reactor, and ethene and butylene are reaction raw materials, unstripped gas weight space velocity 0.01-3h ^-1, temperature 0-300 ℃, pressure 0.1-6.0Mpa, the molecular ratio of the ethylene/butylene in the unstripped gas is 0.2-10;

In the reaction process, when activity of such catalysts is that incipient stability is active 95% the time, catalyzer is shifted out reactor regenerate, regeneration condition is: temperature 300-600 ℃, pressure 0.1-6.0Mpa, regeneration gas are air, O ₂, or/and O ₂With N ₂Gas mixture, weight space velocity 1-30h ^-1, recovery time 2-15 hour, enter into reactor again through regeneration-activatory catalyzer and participate in reaction, circulate with this.

2. the method for claim 1 is characterized in that, the butylene in the reaction raw materials is that butene-1 is or/and butene-2.

3. the method for claim 1 is characterized in that, catalyzer is to shift out reactor continuously or discontinuously.

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