DE1058026B - Process for the production of extruded alumina catalysts or catalyst carriers with high abrasion resistance - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY  PATENT OFFICE

KL. 12g 4 / 0l £ \.

INTERNAT. KL. B Ol j

JgSf /

EXPLAINING PUBLICATION 1058 026

H 26339 IVa / 12 s

REGISTRATION DATE: FEBRUARY 21, 1956

NOTICE THE REGISTRATION AND ISSUE OF THE OUTLOOK: 2 7. M A I 19 5 9

It is already known that the hardness and abrasion resistance, in some cases the performance of a Catalyst, e.g. B. in the dehydration, is influenced by the way in which the carrier is prepared the heavy metal or its compound carries.

For measuring the resistance of catalyst particles to attrition at a minimum size of 2 to 13 mm, a test with a conventional ball mill has long been carried out in the petroleum industry. In this test, a weighed sample of catalyst particles is treated with small amounts Differences in size in a ball mill. In a thick one rotating at 80 revolutions per minute Stainless steel container is left with the catalyst and four stainless steel balls Messed up for 1 hour. The catalyst is then sieved to remove the fines and the proportion of the particles corresponding in size to the original particles is weighed. Of the Percentage (percent by weight) of catalyst particles that were released after being treated in the ball mill for 1 hour retained their original size indicates the degree of resistance of the particles to abrasion. This ball mill test creates very harsh conditions and effects within an hour about as much abrasion as several months of use in a system with a moving layer of the Catalyst particles. To characterize the results of the test with the ball mill was in the The term "hardness index" has generally been used in the oil industry. Because of the different Meanings of the term "hardness" possible confusion, the results here are expressed as a percentage Proportion of large particles indicated after treatment in the ball mill for 1 hour.

In the case of commercial particles of activated alumina with extraordinary breaking strength, which sometimes is referred to as "hard alumina", there was little resistance to abrasion, because after 1 hour treatment in the ball mill, only about 6% of the particles were recovered. As a result The commercially available activated alumina particles are therefore their low resistance to abrasion Process in which the solid particles move from top to bottom due to their weight, unsuitable, although they have excellent breaking strength.

Solid molten corundum beads can be recovered with about 99% of the large beads treated in the ball mill after the test; however, such a high resistance to abrasion is not required for a moving layer made of contact material. It is enough if more than 60% of the Particles used in a migrating layer describe the process of manufacture

extruded alumina catalysts

or catalyst carrier of large size

Abrasion resistance

Applicant:

Houdry Process Corporation, Philadelphia, Pa. (V. St. A.)

Representative: Dr. W. Beil, lawyer, Frankfurt / M.-Höchst, Antoniterstr. 36

Claimed priority: V. St. v. America May 24, 1955

Edward Berbard Cornelius, Swarthmore, Pa.,

Thomas Henry Milliken Jr., Moylan, Pa.,

and George Alexander Mills, Swarthmore, Pa.

(V. St. A.),
have been named as inventors

Test with the ball mill survive, as is the case with industrially used silica-alumina catalysts the case is.

The invention relates to the production of contact material consisting predominantly of alumina with sufficient resistance to abrasion so that more than 6% by weight of the particles are recovered in their large form after treatment in the ball mill for 1 hour . This contact material can be used particularly advantageously in processes with moving layers; however, the contact material can also be used advantageously in other processes. When charging and discharging quiescent beds from the particles produced by the process according to the invention, only relatively little abrasion forms due to the excellent resistance.

The alumina produced in the process according to the invention preferably consists of y- Al ₂ O ₃ ; .es_ can, however, also contain various other forms of sound er.de. such as α-alumina, y-alumina and w-alumina, can be obtained in a manner known per se, depending on which form of alumina trihydrate is used

509 528/393

. ^ jj. ^^^ g ^ ggL ^ ll ^ xg to make a porridge or dough; according to the invention

Jpcraturführung when _C a1cmiercn Chooses_ (Industrial is the converted powder by a Schüttklzud "Eii" ChijlZ Jfhj ^ 195JX to i di stigfüht and can immediately

pcrature tour at _C acmec _ (g

and "Engineering" Chemi ^ tj ^ jlZ Jfahj ^ ng, "195JX brought into the extrusion press and can immediately

P. 14Oi) ^ _- DTeSC alumina Tincl effective catalyst- under high pressures and at high speeds

carriers or catalysts and have structures that are 5 pressed out. The strands of the squeezed

which are characterized by their X-ray spectrum of α-alumina trihydrates are cut into pieces,

differentiate. ^ Clay can be seen in the X-ray. The moldings are immediately after pressing

Spectrum through * the combination of lines at 2.41, and before drying so largely free of excess

1.98 and 1.39 A. y-clay can, depending on the amount of moisture that it

Siurcgrad, the vapor pressure, the absolute pressure, io stick, slide down an inclined slide

the effectiveness of the stabilizer and other fac- and without agglomeration or sticking together

lorcii at temperatures between about 345 and in a shallow layer of falling particles

2000 ⁰ C can be converted into ot-Toncrdc, which can be im.

X-ray spectrum from the combination of strong The first rapid drying of the freshly squeezed

Lines at 3.48, 2.55, 2.08, and 1.60A identify 15 particles. ¹ under conditions of low fertility

wcrdcn can. kcitsgrad is used to prevent development

When wet materials are dried, water becomes large crystallites of aluminum salt in the particles expelled steam. Carefully carried out from a dry zone. Entering this first drying stage Gas flow can a) consist exclusively of water - a further increase in non-steam acts very quickly, b) With water vapor at this temperature, the particles are sticky because they are essentially saturated Air or c) from a mixture of light water with the exception of the water of hydration of the Water vapor and an auxiliary gas exist, which is removed to the constituents.

Regulation of the gas flow within the drying After rapid drying at low humidity

zonc is introduced into this. The space velocity becomes the particle to the distance of the largest

The amount of auxiliary gas can be added, depending on the amount of water by 25 part of the water of hydration and with the formation of

The drying conditions developed water-alumina in a carefully controlled, slow manner

Steam can be adjusted so that in the out of the drying process up to a temperature of about

Dry zone exiting stream a lower Fcuch- JUJiiLG. exposed. This heating decomposes

tigkcitsgrad is maintained by very large also the nitrate anion of aluminum nitrate, so that

Amounts of dry gas through the drying zone are obtained from the aluminum

to be blown. nitrate clay is formed. The temperature is during

According to the invention, alumina particles with several hours of the temperature at which

excellent resistance to abrasion from which the rapid pre-drying was carried out, e.g.

more than 60%> after 1 hour of treatment in the 132 ⁰ C, up to about 315 ⁰ C, possibly up to 425 ° C ,.

Allow ball mill to recover, slowly increased after 35 below. When the temperature of the

Process produced: moldings from 205 to 315 ° C and preferably

Vn1yrM -iformi fr.s Toncrdctrihvdrat is with -conc.c n- during the longest time of heating from 150 to

tric rtcr nitric acid soaked , with as little 425 ° C being in a preferred embodiment

■ F'iussitfkcit is used that the mass has such a high density even after the method of the invention.

the soaking is still powdery and the patency maintained that the vapor concentration

Impregnated powder is 5 to 9, preferably 6 to 8 and preferably at least 50 percent by volume. The fruity

About 7% 100% nitric acid can be obtained in part by reading through a

holds; the acid and trihydrate are left as low space velocity auxiliary gases

1 hour. I) Ci higher temperatures possibly due to the particles heated from 205 to 315 ° C-

also for a little less than 1 hour under education «. When the hydrate disintegrates, steam is

Small amounts of aluminum nitrate are wrapped in the alumina tri, which is allowed to escape so slowly that a

hydrate react with each other; the impregnated and 50% moisture is retained,

The converted powder is then subjected to strong mccha- To remove alkali, the moldings can

with pressure and extruded into particles with, after slow heating with an acid,

ciiicr minimum size of 2 mm, e.g. B. up to 13 mm gc- 50 can be leached.

cut. These particles, which have sufficient cohesion, are sometimes desirable to prevent abrasion

have strength so that they can be handled, permanent particles of y-clayey earth become a dry

for rapid drying under ge atmosphere conditions at a temperature between about 425

Ringer moisture quickly ', in a below 150 and and about 925 ⁰ C to expose their surface for "

above 105 ⁰ C, preferably about 132 ° C, hot chamber 55 clie the requirements of the corresponding use

cingc and leave there for 10 to 5 _t (j> minutes, with the purpose of making the particles suitable. The after

a dry auxiliary gas with, a space velocity the method of the following example 1 hcr-

of more than 10 volume units per volume of the alumina moldings provided have a surface area of

Particles per hour is passed through Äic particles. 200m ² / g, a bulk density of 0.85 kg / l and 94%

The pre-dried particles in this way survived the test in the ball mill with Istündi

Slowly for mchrcrc hours except for at least a short test duration. Various catalysts, e.g. B.

37O ⁰ C heated, with mar ^ dic temperature between chromium oxide dehydrogenation catalysts and platinum ^ 150 and 315 ⁰ C to not ^ 'hr than 28 ° C per hour reforming l ^ atajyjatoren ^ have a longer

can increase and where .at least in temperature usability, if the carrier has a surface area of 205 to 315 ° C, a relatively high area between about 65 and 95 m ² / g, \ 'preferably

Moisture content dadur.fk; is maintained, about 80 m ² / g. It has been found that the <let an auxiliary gas mg ', a low volume alumina moldings resistant to abrasion, also relieve

speed through which XeiJchen guides. Reduce the surface area to their beneficial ab- rishcr was it considered necessary to retain the rub-resistant properties essentially, pressing of the clay trihydrate-sei.ne slurry, 7 "by a known treatment of the form-

1 G58 026

things with a hot, dry gas instead of the velocity of the auxiliary gas. At least 10 and · steam are obtained moldings with a surface area usually more than 20 volumes of air per volume of 90m ² / g and with sufficient resistance to the moldings flow through the mold abrasion per hour, so that 86% of the 1 hour treatment in the object so that protrude from the ball mill from the rapid drying zone. A suitable method entering 5 air flow is a relatively lower z. B. therein, the briquettes is contained for 4 hours at a moisture level. To maintain 900 ⁰ C in completely dry air to heat, processing of low humidity and to remove the but other known methods for surface water within 10 to 60 minutes can be used in general surface treatment. According to the surface treatment, the use of a heated gas stream can be used as a catalyst, such as that used in ovens with forced circulation of the carrier. . Air occurs. The degree of heating depends on the

The moisture content of the y-alumina is also the extent to which each particle is exposed to the hot air depends on this surface treatment. The furnace, in contact, on the space velocity in which the final heating takes place, the air circulation and similar factors are preferably controlled, held between about 730 and about 870 ° C. In the preferred drying process, the molding process preferably takes about 1 to 6 hours, a rapid current for about 10 minutes and heating the particles in the surface drying air having a temperature of 132 ° C can set, in contrast to the slow one.

Heating during treatment at 150 to 315 ⁰ C, after quick drying at low humidity

done quickly. 20 speed, the particles between about 150 and about

The following examples serve to illustrate the 315 ° C slowly dried, whereby the drying

method according to the invention. conditions are controlled so that in the dry

_. -I ₁ ^{zone in which there is a} high degree of humidity. Thieves-

Example 1 resistance of the finished particles to abrasion depends

A certain amount of commercially available alumina tri-35 especially from the control of the conditions

hydrate is sprayed off with an aqueous during the removal of the water of hydration. the

A solution of ^ parts of 67% salpitic acid and 1 part of particles of y-alumina produced in this way

Water is moved in eTner drum, which means that the imprä- usually have a surface area of around 200 m ² / g

gnicrtc alumina trihydrate contain nitric acid and are suitable as carriers for various types of 7.15% (on a 100% basis). Mjin_3 ° of catalysts.

lä ^^ ieSalpejcräure and the alumina trihydrate longer is a catalyst support with a surface of ahT'rSTuncle ^ rniJeinändcr react. If only about 60 to 100m ² / g are desired, then the ttiesel- ^ ZfiTTProberT desTmimpregnated powder can be subjected to a surface treatment of particles by taking them up with distilled water. Such a reduction in the surface can be taken and the pn - If the value of the solution is measured, it shows 35 thermally by rapidly heating the particles on itself; that the first extract a _pH value below 1 up to temperatures exceeding 540 ⁰ C, jedoctrvorzugsweise does not have and that the _pH value of the following extracts more than 760 ° C, to achieve. Rapid heating is immediately while increases until it remains the same at a p _H of about 3 most economic and effective respect. The saturated alumina trihydrate with a controlled removal of part of the residue retains its powder-like properties both initially and after the reaction with the water content of the γ-alumina as slowly as the acid. Heating in this temperature range. Care is required Through the reaction of the acid with the alumina, in order to hydrate the formation of α-alumina, heat is generated and the impregnated one should be avoided.

Alumina usually has to be removed prior to extrusion.

be cooled. If desired, this can be done at any time. B. as a carrier for platinum in one

impregnated powder for 1 day prior to extrusion Catalyst for the 'aromatization or ketormie

store in open containers, which means that both petrol can be used. Furthermore can

Speaking implementation as well as an appropriate one to impregnate the particles with chromium oxide and

Cooling can be achieved. If the extruder do not use it as a dehydrogenation catalyst. Aut Lrrund

Having special cooling devices should give 5 ° of their excellent resistance to abrasion

Powder before it is introduced into the extruder on under the alumina particles or with a catalytic converter

55 ° C. lysator impregnated clay in a fluidized bed

The impregnated, reacted and cooled powder reactor can be used. The improved resistance can be fed to an extruder - if desired by a shaking speed against abrasion, even in processes with a restraint - which is a considerable advantage because the powdery form of the slightly moist material enables the alumina particles according to the invention during the berials will. Form less abrasion with very high mechanical loading and discharge. Pressure is used to compress the powder into strands which are cut up. The pressed moldings adhere to Example 2
hardly stick together and are not so fragile that 60

Using those obtained in Example 1, too large during the following processing operations

Care is required. Chromium oxide supported catalysts made from alumina

Immediately after pressing, they will not only have an advantageous resistance

Moldings to remove most of the anti-abrasion, but also improved catalytic

moisture content a quick dry- 65 Properties. It was found that these catalysts run at a temperature above 105 and below längerjjrauchbar are as similar catalysts at 150 ⁰ C (preferably about 132 ⁰ C) exposed. The water of hydration was not found by using the commercially available alumina carrier for this first drying.

removed. Rapid drying is achieved by means of control. According to Example 1, clay moldings are produced tion of both the temperature and the room temperature and impregnates them to produce a de-

hydrogenation catalyst in a known manner with 20% chromium oxide. Accelerated aging the particles at JOO be ⁰ C for 2 hours / pc alcohol water vapor thermally treated in 2O °. In the same way, a catalyst is treated which differs from that produced according to the invention only in the use of ordinary alumina as the carrier. Technical grade n-butane containing from about 95.1 to about 97% li-bulane, from about 2.7 to about 4.4% isobutane, from about 0.3 to about 0.5% butene, and up to about 0.2% propane , is over the two pre-aged catalysts at a space velocity of 1 V / V / hour. Subjected to dehydration conditions for 10 minutes at 595 ° C. The catalyst according to the invention, which is resistant to attrition, is superior to the conventional catalyst in terms of both selectivity and conversion of the butane.

After treatment in the ball mill for five hours, 93% of those produced according to the invention were retained Particles of chromium oxide on alumina their size, chromium oxide catalyst particles made from common clay carriers were pulverized in the 1 hour ball mill treatment and only 18 per cent of the particles retained their size.

Example 3

After an A ^ cr process which corresponds to that described in Example 1, extruded clay moldings are dried rapidly at about 132 ° C and then slowly heated from about 132 to about 315 ° C with high humidity. The moldings are then cooled and leached with acid to remove alkali. For example, the moldings can be immersed in several fresh solutions of 10% acetic acid for about 1 hour. Instead of acetic acid, nitric acid or aluminum nitrate solutions can also be used for leaching. Traces of sodium salts can be removed more completely if the leaching is carried out immediately after a large part of the water of hydration has been removed by slow drying at a high level of moisture rather than before this step. After heating to about 315 ⁰ C, the sodium can be better traces leach after heating at 790 ° C, however, the alkaline impurities are less well removable.

After leaching with the acid, the briquettes are quickly dried and heated in an oven for 4 hours at -870 ° C. By calcining and surface treatment, the surface of the moldings is reduced from about 200 m ^s / g to about 75 m ² / g. The cooled moldings are wetted with a solution of platinum hydrochloric acid and slowly heated to about 120 ° C., so that about 0.5% platinum is obtained on the abrasion-resistant carrier. This catalyst has a bulk density of 830 g / l and is used as a gasoline reforming catalyst.

Claims (6)

Claims 1. A process for the production of extruded alumina catalysts or catalyst supports with a hardness index above 60 from clay trihydrate impregnated with small amounts of nitric acid with subsequent drying and calcining, characterized in that powdered alumina trihydrate is impregnated with an amount of concentrated nitric acid such that 100 kg of about 5 kg of concentrated powder is impregnated up to 9kg, preferably 7kg, contain 10OVoigc nitric acid, which allows nitric acid to react with the alumina hydrate, the impregnated powder is extruded under strong mechanical pressure and cut into particles with a minimum size of 2 mm, then the extruded particles for 10 to 60 minutes at a temperature between 105 and 150 ⁰ C dries quickly, wherein a stream of a dry auxiliary gas with a space velocity of more than ί 0 volume units per volume of the particles per hour is passed through the particles, the particles predried in this way slowly heated to a temperature of at least about 370 ° C, the temperature between 150 and 315 ° C being allowed to rise no more than about 28 ° C per hour and a high moisture content thereby maintained at least in the temperature range of 205 to 315 ° C is to pass an auxiliary gas with a low space velocity through the particles. 2. The method according to claim 1, characterized in that that the slow heating of the predried particles in the temperature range from 150 to 315 ° C while reading through the auxiliary gas at such a low space velocity that a vapor concentration of more than 50 percent by volume is maintained during the entire slow heating process. 3. The method according to claim 2, characterized in that the slow heating under Maintaining a vapor concentration of more than 50 percent by volume until the Temperature of 425 ° C continues. 4. The method according to claim 1 or 2, characterized characterized in that after slow heating, the particles are leached with an acid. 5. The method according to claim 1 and 2, characterized in that the alumina particles with 10 to 50% chromium oxide impregnated. 6. The method according to claim 1 and 2, characterized in that the alumina particles with 0.1 to 2% platinum impregnated. Considered publications:
German patent specifications No. 664 817, 858 840. Older patents considered:
German Patent No. 1 008 260. O 909 528/393 5.