JP2625380B2 - Periodic regeneration of hydrogen-inactivated solid alkylation catalysts. - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for regenerating a solid alkylation catalyst deactivated by an alkylation reaction with hydrogen.

[0002]

BACKGROUND OF THE INVENTION The use of alkylates as a component of automotive fuel has become widespread and of increasing importance even in the era when antiknock additives such as tetraethyllead are used. Since then, alkylates have become increasingly important automotive fuels. Alkylates are economical, clean-burning, high-octane, low-volatility products, and in some parts of the world, as the composition of gasoline changes with increasing environmental concerns and tighter regulations. Is becoming more and more important. The most important government regulations that make alkylates increasingly important are those relating to lead and butane. Adding lead antiknock agents was the easiest way to increase the octane rating of gasoline, but concerns over the effects of lead emissions have led to a need to remove lead from gasoline, More than 90% of gasoline is already free of lead. Butane is another useful substance that can dramatically increase the octane number, but tends to evaporate from gasoline, especially in warm climates, which contributes to the generation of smog. Recent regulations in the United States call for almost complete removal of butane from gasoline.

The term "alkylate" generally refers to a complex mixture of olefins having two to six carbon atoms present or formed by alkylation of the olefins formed, primarily Alkanes, especially branched alkanes, which are present in the same feedstock, and especially those containing 4 carbon atoms, especially intermediates derived from isobutane. Since trimethylpentanes can significantly increase the octanation of motor fuels, it is most desirable that the complex product mixture, referred to as alkylate, be high in trimethylpentane, but the chemical reaction of alkylation is an alkylation process. Yields a surprisingly wide variety of products arising from the very few basic chemical reaction properties of carbonium ions that play a central role in the process.
Thus, chain transfer (intermolecular hydride transfer and alkyl shift), oligomerization, and disproportionation can result in 5-12 carbons or from raw materials containing olefins or alkanes containing only 4 carbons. Generates an allylate as a by-product containing more.

[0004] Alkylation of olefins is generally catalyzed by strong acids. Intensive research has been conducted on such alkylations in recent decades, and the need to achieve high conversions and maximize selectivity has led to the commercialization of all practical purposes. The most usable catalysts have been limited to sulfuric acid and liquid hydrogen fluoride. Processes based on each of these acids have become widely practiced commercially, but processes based on hydrogen fluoride are preferred, in part because hydrogen fluoride regeneration is easier. It is rare. A brief but valuable overview of alkylation using hydrogen fluoride as a catalyst
“Handbook of PetroleumRefining Proces” by BR Shar
ses ”, RA Meyers, editor, McGraw-Hill Book Comp
any, 1986, pp 1-3-1-28. To put it very simply, the process using hydrogen fluoride as a catalyst is performed as follows. The olefinic and isobutane-based feeds are combined and combined with hydrogen fluoride in the alkylation reaction zone. The effluent from the reactor is separated into the desired alkylate, acid, and other light gases mainly composed of unreacted isobutane. Hydrogen fluoride may be recycled directly to the reactor or may be wholly or partially regenerated before being recycled to the reactor. Unreacted isobutane is also recycled to the reactor, and the alkylate is used to mix automotive fuel. Recently, HF (hydrofluoric acid) has become an environmental problem in the United States. Hydrofluoric acid has been classified as an acute toxicant, and in Southern California, the South Coast Regional Air Quality Control recently requested that the use of hydrogen fluoride in alkylation be eliminated by January 1998. Such bans are expected to be a worldwide trend. As a result, it has become increasingly necessary to find alternatives to fluorination catalysts as alkylation catalysts for alkylate production. It is highly desirable to use a solid acid as an effective catalyst. This is because it allows the development of a fixed bed process, a desirable alternative in the oil refining industry.

[0005]

In particular, it is intended to alkylate olefins containing 2 to 6 carbon atoms with alkanes containing 4 to 6 carbon atoms, a process referred to as motor fuel alkylation. One promising solid catalyst is the reaction product between one or more metal halides with activity as Friedel-Crafts catalysts and refractory inorganic oxides with surface hydroxyl groups,
The refractory inorganic oxide also has a metal having hydrogenation activity for olefins in a dispersed form. Such catalysts are fairly well known in the prior art, as shown, for example, in US Pat. No. 2,990,974, and include, for example, the reaction product of aluminum chloride and platinum. As is usually the case in these cases, these catalysts lose activity during use--this deactivation is measured by the conversion of the olefins--as a method for regenerating these catalysts repeatedly, In other words, regenerating the activity is an absolutely necessary task for maintaining the catalytic activity for a long period of time. It is further desirable that this method of regeneration has as little impact as possible on the motor fuel alkylation process itself. This means that it is most desirable that the catalyst does not come into contact with reaction conditions or chemicals unrelated to the reaction conditions of the alkylation itself or the chemicals therefor. It is further desirable that the time for the regeneration cycle be as short as possible compared to the time for the alkylation cycle. That is, if the overall process cycle time is the sum of the time the catalyst is used in alkylation (alkylation cycle time) and the time the catalyst is being regenerated (regeneration cycle time), the latter should be as short as possible. It is desirable. Of course, the ideal regeneration cycle time is zero, which means that the catalyst is not deactivated, but unfortunately this is not empirically possible. A simple and effective method for regenerating the deactivated catalyst has been found, which satisfies both of the conditions mentioned above. More specifically, after removing the liquid hydrocarbons from the deactivated catalyst, treatment of the catalyst with hydrogen at about the same pressure used in the alkylation process, and at much lower temperatures, results in an inert The reformed catalyst is almost completely regenerated and often leads to higher product quality. This method is simple, very effective in regaining activity and regenerating as many times as necessary, and the required cycle time is within a commercially viable range. U.S. Pat. No. 4,096,933 discloses a Bronsted acid containing a metal halide and fluorine.
acid), the deactivation catalyst of which may be used as an alkylation catalyst, the regeneration process being carried out using hydrogen and a separate noble metal hydrogenation component. The catalyst of this patent is used in the present invention, and the catalyst is not supported, is a liquid,
It differs in many ways, including the fact that it always contains a Bronsted acid bonded to fluorine. In U.S. Pat. No. 3,318,820, Müller et al. Treat hydrogenated isomerization catalysts, which consist essentially of the reaction product of an aluminum halide and an adsorbent (solid) containing surface hydroxyl groups such as alumina and silica. Then, a regeneration method of treating with gaseous hydrogen chloride is described. No precious metal hydrogenation component is described, and in the regeneration process, treatment after hydrogen treatment with hydrogen chloride is indispensable.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a solid metal halide catalyst which has reacted with surface hydroxyl groups of a refractory inorganic oxide and which also contains a small amount of metal active in hydrogenation. If it is used as a phase alkylation catalyst and has been inactivated, its activity is to be regenerated repeatedly. One embodiment includes treating the catalyst with substantially all of the liquid phase removed with hydrogen at a temperature in the range of 10 to 300 ° C. and a hydrogen partial pressure in the range of 6.9 to 13790 kPa. In a more particular embodiment, the refractory inorganic oxide is alumina. In another particular embodiment, the metal halide is aluminum chloride. In an even more specific embodiment, the metal halide is aluminum chloride, the refractory inorganic oxide is alumina, and the metal having hydrogenation activity is platinum. In another embodiment, the catalyst is treated in the presence of liquid isobutane and a source of chloride at the temperatures and pressures described above.

A group of catalysts which can be characterized as reaction products of Friedel-Crafts active metal halides and surface hydroxyl groups of inorganic oxides, and which further comprise a metal having hydrogenation activity, are valuable alkylates as automotive fuel components. Although promising in the liquid-phase alkylation of alkenes with alkanes to produce, these catalysts are rapidly deactivated. Accordingly, there is a need to develop a method for regenerating the catalyst, which is preferably relatively simple, inexpensive, and effective in regenerating the catalyst activity over many repetition cycles. The present invention substantially removes the liquid phase reaction mixture from the catalyst and requires a minimum of 10 ° C.
Of the catalyst with hydrogen at a temperature of from 300 to 300 ° C. and a hydrogen partial pressure of at least 6.9 to 13790 kPa. Treatment of the catalyst with hydrogen may be a substantially liquid free catalyst,
Alternatively, it can be performed in the presence of liquid isobutane and a source of chloride. The catalysts used in the present invention are also well known in the prior art (see U.S. Pat. Nos. 2,990,974 and 3,318,820) and need not be discussed at length here; The following description will suffice to get you. Refractory inorganic oxides suitable for use in the present invention is at least 35m ² / g or more, preferably 50 m ² / g or more, more preferably 100 m ²
/ g or more surface area. Although some exceptions are known, it is advantageous to use a material with the largest possible surface area. Suitable refractory inorganic oxides include alumina, titania, zirconia, silica, boria, silica-alumina, aluminum phosphate, and combinations thereof. Of these, alumina is particularly preferred. Surface area of at least 35m ² or more, as long as it has a surface hydroxyl group, alpha practical reasons - with the exception of alumina, can be used in any alumina phase, the various phases is as motor fuel alkylation catalyst Are not necessarily the same.

The refractory inorganic oxide needs to have surface hydroxyl groups, but that does not mean absorbed water, but rather its oxygen binds to the metal of the inorganic oxide. Means a hydroxyl (OH) group. These latter hydroxyl groups are sometimes referred to as chemically bonded hydroxyls. Since the presence of absorbed water is fundamentally a negative factor in the preparation of the catalysts of the present invention, the refractory inorganic oxides are first used, most commonly, without chemically modifying other hydroxyl groups. And treating by calcination at a temperature suitable for individually and preferentially removing physically absorbed water to remove surface hydroxyl groups. For example, when the refractory inorganic oxide is alumina, a temperature of 350 ° C to 700 ° C is preferable. The metal having hydrogenation activity is usually deposited on the surface of the refractory inorganic oxide before its surface hydroxyl groups begin to react with the metal halide. Although such procedures are commonly practiced and found to be effective, the methods for obtaining effective catalysts are not limited to this. Metals found to be particularly effective include nickel and platinum, palladium, ruthenium, rhodium, osmium,
And noble metals such as iridium. Of the noble metals, platinum and palladium are more desirable than others. These desired metals can be complexed with the refractory inorganic oxide in any desired manner such as impregnation, co-precipitation, immersion, and the like. These methods are well known and need not be described here. The metal content is about 0.01 to 1.0 percent by weight based on the weight of the final catalyst for noble metals, and about 0.1 to 5 percent by weight for nickel. Suitable for drying the composite of metal and refractory inorganic oxide to remove physically absorbed water, but not to remove "chemically bound" hydroxyl groups. It is fired under the mild conditions. After depositing and firing the metal, the surface hydroxyl groups of the refractory inorganic oxide are reacted with a metal halide having Friedel-Crafts activity. The metals used include aluminum, zirconium, tin, tantalum, titanium, gallium, antimony, phosphorus, boron, and the like. Suitable halides are fluoride, chloride, and bromide. Representative of these metal halides are aluminum chloride, aluminum bromide,
Iron chloride, zirconium chloride, zirconium bromide, boron trifluoride, phosphorus chloride, phosphorus fluoride and the like. Of these metal halides, aluminum halides are desirable, and aluminum chloride is particularly desirable. Except for boron trifluoride, chloride is a generally preferred halide.

The reaction between the metal halide according to the invention and the surface hydroxyl groups of the refractory inorganic oxide is carried out, for example, by metal-
It can be easily carried out by sublimating or distilling the metal halide on the particles of the inorganic acid composite material. This reaction involves the disappearance of about 0.5 to 2.0 moles of hydrogen halide per mole of metal halide absorbed therein.
When the metal halide reacts in the gas phase, the reaction temperature depends on the reactivity of the metal halide, its sublimation temperature or boiling point, and the properties of the refractory inorganic oxide. For example, when aluminum chloride and alumina are used as shown here, the reaction easily occurs in a temperature range from about 190 ° C to about 600 ° C. The following methods have been found to be very effective in regaining the activity lost to such catalysts, and even over many regeneration cycles. First of all, it is necessary to remove essentially all of the liquid reaction mixture from the catalyst, but this can be done very simply by discharging all the liquid phase from the catalyst. After removing the liquid phase, the catalyst is treated with hydrogen at a partial pressure in the range of about 6.9 to 13790 kPa (1 to 2,000 psi). The temperature at which the catalyst is treated with hydrogen ranges from 10 to 300 ° C. The time required for regeneration depends on the temperature. Consequently, higher temperatures are desirable if shorter regeneration times are desired, and for this reason temperatures above 300 ° C. may be used, but these are generally not recommended . Generally, a time of about 1 to 20 hours is sufficient. However, other conditions require rather low temperature regeneration. Regeneration at the conditions of the alkylation process is most desirable in order to avoid heating and cooling costs and to make the operation for regeneration simpler and easier. In fact, playback is
It is preferable to perform the reaction in a temperature range of about 10 ° C to about 200 ° C. In this case, in order to restore the activity with the maximum efficiency,
A reproduction time of about 6 hours is sufficient.

The following example illustrates the invention. General Procedure: General alkylation test conditions include a temperature of 10 ° C., a reaction pressure of 3200 kPa (450 psig), and an L of butene-2.
HSV 0.2 hr ~ ¹ , and the molar ratio of isobutane / butene is 1
00, 75, 45 or 20. 2,000 ppm alkylation
The reaction was carried out under the presence of (in the form of butyl chloride) and of hydrogen in a ratio of 0.25 mol per mol of butene. Regeneration of the catalyst with hydrogen was performed as follows.
At the end of the process cycle (ie, when the catalyst was clearly deactivated), isobutane was introduced at a rate of 1 LHSV and the isobutane / olefin feed was shut off. After flushing at a temperature of 10 ° C. for 2 hours, the pressure of the reaction system is reduced to 101 kPa (1 atm), and then hydrogen is introduced together with 10 to 1000 ppm of chlorine in the form of butyl chloride.
The reaction was then pressurized to 320 kPa (450 psig). Temperature is 2
Raised to 00 ° C. and maintained at that temperature for 4 hours, after which the reactor is cooled to 10 ° C. over a period of about 2 hours,
Then, it was filled with isobutane and flushed for about 1 to 2 hours. The entire procedure took about 10 hours.

[0011]

Example 1 Regeneration with pure hydrogen: 0.75 weight percent
A catalyst was prepared containing 0.25 weight percent platinum on a 1.6 mm (1/16 ″) gamma alumina extrudate having aluminum chloride equivalent to Al sublimated on the surface (aluminum content). Was not measured directly, but was determined based on the chlorine content.) The catalyst was then treated with a chloride source to contain 3-7 weight percent chloride in the first step. Suitable chloride sources are alkyl chlorides, or hydrogen chloride, etc. The catalyst was used for automotive fuel alkylation under the conditions described above and was further regenerated as described above in 10 process cycles. There was no observable loss of activity from the second cycle to the tenth cycle performed at an isobutane / butene molar ratio of 45. The average alkane product research octane number (RON) was All were 89 about a cycle of. Using the same catalyst without the platinum, the control is performed. In this case, regeneration was observed.
After the hydrotreatment, the catalyst was still in an inactive state, and no measurable reactivation was observed. A similar experiment was performed using gallium chloride GaCl ₃ instead of aluminum chloride. Although the regeneration test was not performed extensively, the catalyst deactivated under the conditions described above was completely regenerated. The alkylate formed showed a RON of 90.5. In another experiment, in an aluminum chloride-alumina catalyst, 0.5 instead of platinum was used.
Weight percent palladium was used. Regeneration was good and the average alkylate product RON was around 88.5.

[0012]

Example 2 Regeneration with isobutane, butyl chloride and hydrogen: regeneration in an isobutane-hydrogen stream showed chloride loss and subsequent deactivation of the catalyst, so regeneration was carried out with butyl chloride. It is highly desirable to perform the regeneration in the presence. In such regeneration, 0.0283m ³ / hr
Isobutane and hydrogen containing 1,000 ppm of chlorine (in the form of butyl chloride), supplied at a rate of 1 standard cubic foot per hour, were shut off at the end of the process cycle, while the feed of the feed blend was also shut off. After flushing for 2 hours, the pressure increased to 4238 kPa (600 psig) and the temperature increased to about 130 ° C., and the state was maintained for 12 hours. After cooling the catalyst composite to 10 ° C., the feed mixture was shut off and the regeneration gas flow was shut off. The time required for the entire procedure was on the order of 16-18 hours. The catalyst with aluminum chloride deposited on a gamma alumina extrudate containing 0.25 weight percent platinum was easily regenerated under the conditions described above and provided an alkylate product with an average RON of 90.5. If the regeneration gas stream does not contain butyl chloride, the catalyst initially deactivates rapidly. This indicates that when liquid isobutane is present with hydrogen as a representative hydrocarbon, it is desirable, but not necessary, that butyl chloride be present in the regeneration stream. Another experiment has shown that replacing platinum with 0.5 weight percent of palladium or nickel provides a catalyst that can be regenerated under the same conditions as described above. In all of the latter catalysts, the product alkylate exhibited an average RON of 88.5. The catalyst with gallium chloride supported on a gamma alumina extrudate containing 0.25 weight percent palladium was also regenerated eight times with no apparent loss in activity or stability under the conditions described above. Played under easily. Regeneration was performed using soluble hydrogen, ie, hydrogen saturated with liquid isobutane, but the stability of the catalyst was reduced, as indicated by a shorter process cycle than before deactivation began. 1) Zirconium tetrachloride ZrCl ₄ on alumina containing 0.25 weight percent platinum; 2) titanium tetrachloride Ti on gamma alumina containing 0.25 weight percent platinum.
Catalysts prepared by sublimation of aluminum chloride, respectively, on spherical silica-alumina (silica: 70-90 weight percent) with Cl ₄ and 0.25 weight percent platinum can also be regenerated through multiple process cycles. It has been shown. In all cases, the alkylate produced had an average RON of 88-89. The catalyst was prepared by boron trifluoride BF ₃ adjustment alumina may not include a 0.25 wt% platinum. When platinum was not included, the catalyst was not regenerated, but when platinum was included, the catalyst was regenerated in multiple cycles using either this procedure or the procedure of Example 1. In all cases, the product alkylate had an average RON of 91.5.

[0013]

Industrial Applicability The present invention is an industrially extremely useful invention in which a solid alkylation catalyst which has been inactivated by an alkylation reaction can be easily activated, reduced in cost and quickly activated.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Jojif A. Cocal United States 60031 Illinois, Garni, Hikari Haven 211 (56) Reference JP 50-59303 (JP, A)

Claims (6)

(57) [Claims] 1. A method for regenerating an alkylated solid catalyst, comprising:
The catalyst comprises: 1) a reaction product of a first metal halide and a hydroxyl group bonded to the surface of the refractory inorganic oxide; and 2)
A catalyst containing a second metal, wherein the first metal halide is a fluoride, chloride or bromide, and the first metal is aluminum, zirconium, tin, tantalum, titanium, gallium, antimony, phosphorus, boron And the second metal is selected from the group consisting of platinum, palladium, nickel, ruthenium, rhodium, osmium, iridium, and mixtures thereof. Wherein the catalyst is an alkane having 4 to 6 carbon atoms,
In a method for regenerating a catalyst in which at least a part of the alkene is inactivated by liquid phase alkylation, substantially all of the liquid phase hydrocarbons are removed from the catalyst, and the obtained catalyst is used in an amount of from 6.9 to 6.9. With hydrogen at a partial pressure of 3790 kPa,
A method for regenerating a solid alkylation catalyst, comprising recovering a regenerated catalyst having substantially enhanced alkylation activity by treating at 10 to 300 ° C for 20 hours. 2. The method of claim 1, wherein the first metal is selected from the group consisting of aluminum, zirconium, titanium, gallium, boron, and any combination thereof. 3. The method of claim 1, wherein the second metal is platinum, palladium, or any combination thereof. 4. The process according to claim 1, wherein the catalyst is treated with hydrogen at a temperature of from 10 to 200 ° C. 5. The process according to claim 1, wherein the hydrotreating is carried out in the presence of a chloride source. 6. The process according to claim 1, wherein the hydrotreating is carried out in the presence of liquid isobutane and a chloride source.