DE1207534B - Process for reforming heavy gasoline - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. α .:

Clog

German KL: 23 b -1/04

Number: 1207 534

File number: S 74920IV d / 23 b

Filing date: July 20, 1961

Opening day: December 23, 1965

The invention relates to a method for reforming heavy gasoline at pressures between Atmospheric pressure and 70.3 atmospheres using a platinum group and reforming catalyst Adjustment of the water vapor partial pressure in the reaction zone.

According to the invention, it is carried out under comparatively dry reforming conditions, wherein the water vapor partial pressure in the reaction mixture withdrawn from the reaction zone is below a certain limit value is kept. The method according to the invention is in particular at Pressures not carried out above 28.1 atmospheres and preferably 14.1 atmospheres. Appropriate is with a catalyst worked before the reforming in a on the reforming process has been pretreated or conditioned in a coordinated manner.

It is known that water can enter the reaction zone from essentially three sources, viz. Through the feed, through the hydrogen recycle gas, and through the catalyst. Reforming catalysts with oxides or sulfides of the metals from the groups IV, V, VI, VII and VIII of the Periodic Table containing 5 0.2 and 1.0 weight percent water after regeneration between ^a. It has been suggested that the regenerated catalyst should be dried in a stripping zone to a moisture content between 0.1 and 0.8 weight percent.

There have also been numerous discussions about the influence of the water vapor content in the circulating gas on the activity, the selectivity and the reformate yield in the implementation of heavy gasoline Platinum group reforming catalysts have been employed. It is known the moisture content of the reaction mixture coming for reforming to a water vapor content of less than 0.03 percent by volume to adjust. This known method and other prior proposals are indicative only on the importance of adjusting the moisture content, but they do not convey an unambiguous one Teaching how to reform under favorable conditions and avoid loss of exploitation can be carried out.

According to the invention it has been found that it is by no means sufficient to reform with only one Water vapor content below 0.03 percent by volume. Surprisingly, it has been found that an upper limit of the moisture content, which is well below 0.03 percent by volume, is not exceeded If this limit should be over-method of reforming heavy gasoline

Applicant:

Socony Mobil Oil Company, Inc.,

New York, N.Y. (V. St. A.)

Representative:

Dr. E. Wiegand and Dipl.-Ing. W. Niemann,

Patent Attorneys, Munich 15, Nussbaumstr. 10

Named as inventor:

Leon Marvin Capsuto, Woodbury, N.J.

(V. St. A.)

Claimed priority:

V. St. v. America of July 28, 1960 (45 827)

is stepped, despite an operation with a moisture content below 0.03 percent by volume Achieved significantly lower yields than when using a moisture content can be obtained below this limit determined according to the invention.

The method according to the invention for reforming heavy gasoline at pressures between Atmospheric pressure and 70.3 atmospheres using a platinum group and reforming catalyst Adjustment of the water vapor partial pressure is characterized in that in the reaction zone the Adjusts water vapor partial pressure so that the withdrawing reaction mixture has a water vapor partial pressure of 0.2 mm Hg or less, measured at 14.05 atmospheres.

The dry reforming is significantly improved by the method according to the invention, in particular the reformate yields are significantly increased. For example, by applying the invention, the dry reforming of the C ₆ -121 ° C fraction of a mid-continent heavy gasoline at 14.1 atmospheres over operating periods of 93 days with the production of a gasoline with a Reid vapor pressure of 10 RVP and a research Leaded octane number (R + 3 cm ³ tetraethyl lead) from 109 to 111 can be carried out.

As mentioned earlier, there are three sources of water content in the reaction zone: The one used Heavy gasoline usually contains up to about 0.0Ql to

509 759/509

3 4

0.0015% water; 0.0015% water in the feed is only reduced by about 12% more if the humid

control, however, at a total pressure in the reactivity of the gas around 600 ^σ / ₀ to 140 mm Hg.

tion zone of 14.1 atü is only increased by about 0.08 mm Hg. At 371 ⁰ C, the chlorine content of the

Total partial pressure of water in the reaction zone. Catalyst by contact with a gas of

An undried circulating gas only increases this water vapor partial pressure 5 140 mm Hg slightly.

content up to 0.5 to 2.0 mm Hg. Such a partial fugig reduced. On the other hand, the surface

pressure leads to a lower volume yield of a catalyst with an original upper

C ₅ + reformate from a C ₅ -121 ° C cut, as if the area was reduced from 430m ² / g to less than 200m ² / g

the partial pressure in the outflowing material from the decreases when the catalyst is at 482 ° C with a gas

last reaction zone according to the invention in the range of 60 mm Hg water vapor partial pressure or at

is maintained between 0.05 and 0.2 mm Hg. 538 ° C with a gas of 20 mm Hg water vapor

By reducing the moisture content, the partial pressure is brought into contact.

Vapors in the reaction zone, measured at the outlet If, for example, the water vapor partial pressure

from the last reactor, the yield can be 5 mm Hg, the surface area reduction is

C ₅ + reformate having an octane number (research octane 15 at temperatures of 371-482 ° C between

number with the addition of 3 ecm tetraethyl lead) of 104 from about 3.6 and 14.5%

a C ₅ -132 ° C feed for which the pressure is 100 mm Hg, the surface loss is

Loading, for example increased by about 2% between about 23.4 and about 50.7%

will. This means a very essential tech- In order to avoid a reduction in the surface,

niche and economic improvement. 20 the moisture content in the catalyst

The moisture content of the circulating gas or the gas phase affects its temperature

also impairs the yield in the production of environment to be matched. So a catalyst

high octane C ₅ + reformate from a C ₅ -121 ° C- sator with a surface area of 400 m ² / g not one

Feed material, even if the moisture content is exposed to the gas phase in which the water partial

of heavy gasoline only 0.0015 percent by weight is more than 5 mm Hg at temperatures of 371 ° C

carries and the catalyst at 482 to 538 ⁰ C to one and higher. On the other hand, a catalyst can

Moisture content of about 1.1 weight percent with a surface area of 200 m ² / g with no substantial

above the moisture content determined by the catalyst to reduce the surface area of a gas phase.

is retained during drying at 1250 ° C, dried is set in which the water vapor partial pressure

has been. Without drying the circulating gas, 3 ° over 100 mm Hg at temperatures in the range

and supplying a heavy gasoline charge on the order of 468 to 538 ° C. This knowledge

0.0015% water about 6 days is required for conditioning both fresh and fresh

System reaches a state of equilibrium. Even if important from used catalyst,

On the other hand, the circulating gas is dried and the It is of the utmost importance to the surface of the

Keep catalyst to a water content of less than 35 catalyst initially as high as that at

1.1 percent by weight of water above which at 125O ⁰ C normal yield distribution is not possible, so

If the retained water content is dried, the surface loss does not occur within the surface

If the system reaches the state of equilibrium in about an operating span that is too short to a technical one

1.5 days. If the circulating gas is not dried, the unusable value is reduced. Especially for the

In addition, the yield of C ₅ + reformate 40 reforming under low pressures does not remain

about 1 percent by volume less than when circulating gas is 28.1 atm, a platinum group catalyst is preferably

and catalyst according to the invention so dried with a surface area of at least 200 m ² / g

that the water contents of feedstock and preferably at least 300 m ² / g are used,

and circulating gas together a water vapor In Fi g. 3 A indicates the line AB the minimum

partial pressure in the outflowing reaction mixture 45 surface, which is necessary for an acceptable performance of a

does not result in more than 0.2 mm Hg. Platinum group metal reforming catalyst in the

The moisture content of the catalyst plays low pressure reforming is required, i. H. one

also an essential role for the water vapor surface area of at least 200 m ² / g. The CD line

partial pressure in which flow out of the reaction zone in Fig. 3A indicates the minimum surface area that

the product. The surface area of the alumina 50 in the low pressure reforming, i.e. H. Do not press

carrier and the chlorine content of the catalyst is above 28.1 atm and preferably about 3.5 to

due to the moisture content of the 17.6 atmospheres preferred with the catalyst. The experimental

the gas in contact and the temperature conditions for diagrams 3 A and 3 B

temperature of this gas is impaired. This is generally consistent with those of Diagrams 2A in the figures

2A and 2B. 55 and 2B match.

Fresh platinum was used in these studies. The data presented in Figures 3A and 3B

Reforming catalysts with 0.6 percent by weight platinum are summarized in FIG. 3C. The curves

and 0.67 weight percent chlorine for 48 hours at in Figure 3C illustrate the temperatures at

Normal pressure and the given temperatures with which platinum group metal reforming catalysts with

Air brought into contact with water in the various surface sizes in the presence of

showed amounts contained. The total amount of water, gases with the specified water vapor partial

with which the catalyst can be heated during the individual compressions (mm Hg) without

search came into contact, there was a significant reduction in the surface area in all cases,

and amounted to about 20 percent by weight of the catalyst with surface areas of 350m ² / g or

sators. It can be seen that even at 371 ° C the 65 below can in the presence of gas with a

Surface of the catalyst decreased by about 15 %- water vapor partial pressure of 100 mm Hg without one

goes when the water vapor partial pressure in the gas significantly reduces the surface to tempe-

Is 20 mm Hg. On the other hand, the surface temperatures will be heated to between about 343 and 465 ⁰ C.

5 6

Catalysts with a surface above group metal ref ormierkatalysator with such a 350 m ² / g can only in the presence of gas with a moisture content that at the above-water vapor partial pressure does not exceed 10 mm Hg on given treatment of the partial pressure of the water at temperatures in Range from 316 to 538 ⁰ C without gas, measured at the pump outlet of the container, can be heated to substantial surface loss. 5 increases less than about 3 to 6 mm Hg.

F i g. 4 shows the influence of the partial pressure of water. A "conditioned" catalyst is also defined

in the manufacture of a product with a research as an unused or regenerated solid granular octane number leaded (RON with the addition of 3 ecm platinum group metal reforming catalyst with a tetraethyl lead) from 109 to 112 from the C _e -121 ° C moisture content not more than 1 , a Mid-Continent-heavy gasoline io higher atü 1 percent by weight fraction at a moisture content of not konditioeinem total pressure of 14.05, an hourly ned catalyst after firing at 1250 ⁰ C space velocity of the liquid of more than 48 hours.

0.8 and a vapor inlet temperature of 515 ° C. Under "Conditioning" a working method is closed

In particular, it is of interest to understand the yield at which a granular solid platinum group is about 4% decreases when the partial pressure of water in the 15 metal reforming catalyst with a drying feedstock, d. H. Heavy gasoline plus circulating gas, gas in contact with dewatering temperatures is increased to over 0.2 mm Hg. In the range of is brought, the temperature of the drying -0.25 up to 8.0 mm Hg, on the other hand, practically no outgassing is changed in the manner described later observed. Water vapor partial pressure mood with the water partial pressure, measured on from 0.25 to 8.0 mm Hg corresponds to the reaction zone with a total steam outlet, and with the upper pressure 14 atmospheres water content of about 0.002 area of the catalyst before conditioning up to 0.07 percent by volume. In the case of the aforementioned is regulated.

known processes in which the water contents are below a "reaction zone" comprises one or more

0.03 percent by volume and in particular in the area of reactors, which each have a stationary catalyst bed and 0.01 to 0.03 percent by volume, 25 at least one inlet for vaporous and gas becomes critical well above the reactants characteristic of the invention and a vapor characterizing reaction Have limit in an area outlet. If several reactors have been prepared in advance, in which, according to the findings, the steam outlet is the reaction zone, and the yield is approximately 4% lower. at which the partial pressure of the water is measured, some indication of the critical limit of 30 the vapor outlet of the last reactor.
0.2 mm Hg water vapor partial pressure is “a drying gas” is a gas with which “not

known procedures cannot be found. On the other hand, conditioned «catalyst according to the above Deist it is clear that a yield increase of 4% is a finition for dewatering or drying and growing Represents progress. position of "conditioned" catalyst in contact

In the method according to the invention, the aim is to bring about the 35 tion. The "drying gas" cannot exceed 0.2 mm Hg from the total amount of the three sources nitrogen, exhaust gas with no more than 50 percent by volume of water introduced. of oxides of carbon, hydrogen, hydrogen - accordingly, the extent to which the moisture-containing gas, such as circulating gas with hydrogen and any of the components heavy _{gasoline - C 1} - to C ₄ hydrocarbons, or air, are used, circulating gas and Catalyst is reduced, 40 A heavy gasoline feedstock with "harmless quantities largely dependent on the moisture content" of sulfur, nitrogen, arsenic and lead is the other two components. The heavy gasoline is a heavy gasoline with an amount of sulfur that is not preferably dried to less than 0.001 weight percent water for a noticeable reduction in activity. The recycle gas, the reforming catalyst and an impermissible one, is generally dried so that it does not contain more than about 45 percent corrosion of the feedstock in contact with 0.0005 parts by volume of water. The catalyst, coming iron parts is sufficient, no more than that originally contains a surface area of 300 to 400 m ² / g 0.0001% nitrogen and has essentially free or more, is conditioned so that it is an upper one of arsenic and lead . "Substantially free of area of at least 200 m ² / g and preferably of arsenic and lead" means a concentration of at least 300 m ² / g. 50 arsenic and / or lead in the feedstock of the reforming

At this point, some will be used in the following, which are used when the Reformer is brought into contact Terms defined: feedstock with a resting bed of a solid

An "unconditioned" catalyst is a granular platinum group metal reforming catalyst unused or regenerated, solid granular with about 0.35 percent by weight platinum is insufficient, platinum group metal reforming catalyst with a 55 μm catalyst within its service life of such a moisture content that when in contact with, for example, 2 Years of inactive; Bringing in a container of 50 ⁰ C with a gas, the life of the catalyst is determined by other factors such as air, hydrogen, hydrogen-containing gas with factors, such as those for the production of at least 90 percent by volume of hydrogen and the reformate with an octane number of at least 100 remainder of C ₁ - to C ₄ hydrocarbons, or nitrogen, 6 ° (research octane number with the addition of 3 cm ^{3 of} tetram with a water partial pressure of less than 0.1 mm ethyl lead) required temperature, the reformate Hg in a flow rate of about 710 yield and the mechanical strength of the Katabis 1440 Nm ³ gas per hour and cubic meter of catalyst.

sator the partial pressure of water in this gas to more The platinum group metal reforming catalyst

than 3 to 6 mm Hg, measured at the steam outlet this 65 acts as a desiccant and can at atmospheric Container, is increased. Conditions related to temperature, humidity

A "conditioned" catalyst is an unpressurized and pressurized up to 8 percent by weight of water or take regenerated, solid granular platinum.

The platinum group metal reforming catalyst carrier acts as a desiccant. Since the carrier often consists essentially of alumina, the properties of γ-alumina are decisive for the ability to absorb and release water from and to the environment. The moisture content of alumina, which has ^{been heated to constant weight at 1250 °} C. in dry air, is used below as a basis for comparison. The amount of water that exceeds the water content of a fired at 1250 ⁰ C in a dry .Luft alumina sample is referred to as a reversible water. According to the invention, a granular solid platinum group metal reforming catalyst with a high-melting oxide carrier acting as a desiccant is preferably conditioned until the moisture content is such that when the catalyst is used for reforming heavy gasoline with no more than 0.0013% water in the presence of circulating gas no more than 0.0005 percent by volume of water, ie a partial pressure of less than 0.6 mm Hg, the material emerging from the reaction zone has a water partial pressure of no more than about 0.2 mm Hg. A solid granular platinum group metal reforming catalyst with an alumina support is preferably conditioned until the catalyst has a moisture content no more than about 1.1 percent by weight above the moisture content of the catalyst after combustion at 1250 ^° C. The reversible water content of the conditioned catalyst therefore does not exceed 1.1 percent by weight.

Some of the water absorbed from the transport containers during filling and filling after production is removed in the course of the usual start-up measures of a reforming plant, i.e. during flushing with inert gas to remove air, flushing with hydrogen to remove the inert gas and heating of the catalyst on the reaction temperature of the reforming. However, a significant amount of water is also retained by the catalyst unless special measures are taken. This water is released after the system has been commissioned. After several days of operation, an equilibrium is established between the water on the catalyst and the water in the catalyst environment, and the water content of the circulating gas drops to a level that depends on the moisture content of the heavy gasoline feedstock and the operating temperature of the liquid-gas separator in which the Separation of the circulating gas from Q-hydrocarbons and the heavier reformate takes place, is dependent. The moisture contents of four separated at different Drükken and 21 ⁰ C, saturated Umwälzgasen are listed in Table I.

Table I.

Water content of the saturated gas pressure at 21 ° C in percent by volume atii Vapor pressure = 18.8 mm Hg 0 2,470 7.0 0.3165 14.1 0.169 35.2 0.0706

The water content of the gas increases when it passes through at 21 ⁰ C. Gas with such water contents can be a

the catalyst bed flows. Therefore, the water can have an adverse effect on the catalyst. In

partial pressures in the gas with the catalyst at 45 of Table II are the partial pressures of water at

Bottom of the catalyst bed is in contact, higher various total pressures in gases with 0.0001 vol-

be compiled as 18.8 mm Hg, the vapor pressure of water lum percent water.

Table II

Pressure atü

Water vapor partial pressure in gas

with 0.0001 percent by volume water

mm Hg

7.0 14.1 35.2

7.60 10- *
5.95 · IO- ³
1.11 × 10- ²
2.70 · 10- ²

The data given in Table III clearly show that humidity control in the in gas entering the catalyst bed protects the first section of the catalyst bed. However, will the water removed by the gas from the first section of the catalyst bed, all subsequently Damage through which the gas and the stripped water flowed sections of the catalyst bed. Accordingly, in order to protect the entire catalyst bed, the moisture content of the das Catalyst bed leaving gas can be regulated.

'Table III

10

Location of the catalyst

Fresh catalyst

Attempt no.

Drying temperature ^{in 0 C}

232 and 510
Remaining
surface

26.7 to 538 remaining surface

Surface in m ² / g

Above

center

Below

Breaking strength in kg

Above

center

Below

420 to 450
Medium: 435

4.3 to 5.0
Medium: 5.1

392
385
213

90.1 88.4 48.9

392

377 362

90.1 86.7 83.3

3.26
2.63
3.26

5.0

Conditions:

Experiment no. 1:

300 to 450 volumes of hydrogen per hour and per volume of catalyst over a period of 2 hours at 232 ° C; then 300 to 450 volumes of hydrogen per hour and per volume of catalyst at 510 ^° C. over a period of 3 hours.

Experiment No. 2:

700 to 1500 volumes of hydrogen per hour and per volume of catalyst over 8 to 30 hours for each of the following Temperatures: 26.7, 93, 232, 371, 427, 482, 538 ° C.

When the fresh catalyst is dried with a relatively small volume of gas and the temperature of the catalyst was increased relatively quickly, the surface area of the catalyst decreased at the bottom of the reactor by about 51%. On the other hand, when the temperature of the catalyst is in the presence of an "infinite volume of gas" was increased relatively slowly, the surface of the Catalyst at the bottom of the reactor only by about 7% and only by 3 to 7% more than the surface of the catalytic converter at the top or in the middle parts

of the reactor. It can be seen from this that the water removed from the catalyst in a reactor section has an adverse effect on the catalyst, which is subsequently brought into contact with the gas containing the stripped water, provided that the temperature of the catalyst in the subsequently flowed through part of the catalyst bed in the Area of 510 ⁰ C.

The previous conclusions are confirmed by the data given in Table IV.

Table IV

Catalyst treatment

Load to break mean values kg

Fresh catalyst

Fresh catalyst, dried for 2 hours at 115.6 ⁰ C.

Fresh catalyst, dried for 2 hours at 482 ° C

Fresh catalyst, heating with a temperature increase of 2.2 ° C / min. to 482 ^° C; Drying for 2 hours at 482 ° C, cooling in an open oven; all operations under the own gas phase

Fresh catalyst, same treatment as under No. 4 with the exception, that dried air is passed over the catalyst at a flow rate of 2 volumes per volume of catalyst per hour until drying was complete

Fresh catalyst, same treatment as under No. 5 with the exception, that instead of dried air, hydrogen was used ...

Used but not regenerated catalyst after 276 days of production of gasoline with an octane number (leaded) of 104; Loading 8.8 m ³ heavy gasoline per kilogram of catalyst

Used but not regenerated catalyst after one day of operation producing gasoline with an octane number (leaded) of 98; Load 70.2 liters of heavy fuel per kilogram of catalyst ...

4.14 ± 0.50 3.82 ± 0.33 3.30 ± 0.31

1.58 ± 0.09

4.48 ± 0.22

4.59 ± 0.23

about half the value for the fresh catalyst

509 759/509

The influence of moisture in the circulating gas is water and a circulating gas with no more than shown in FIG. 5 emerges. A C ₅ -132 ° C fraction of 0.0005 percent by volume of water, ie a water mid-continent heavy gasoline, was fed at a reactive partial pressure of less than 0.06 mm Hg, gate pressure of 12.3 atmospheres and an hourly rate To become space. If necessary, the drying treatment flow rate of the liquid can be continued from 1 to 5 treatment at temperatures of 538 ° C, production of leaded gasolines with the required, if the water partial pressure is reformed in the octane number given from the reac; for this purpose, a 1 mm Hg non-overflow reforming catalyst with a weight of 0.6% was used. However, even in the presence of such a gas, percent platinum and 0.7 percent by weight chlorine on the catalyst will not contain an alumina-containing carrier beyond a temperature. In the first io heated, which is about 11 ⁰ C below the temperature level, the circulating gas is at a moisture point at which the catalyst irreversibly content of about 0.0001 percent by volume (0.01 mm Hg is inactivated.

Water partial pressure) dried; In the second stage the above-described preferred drying was the circulating gas was not dried, it contained method in terms of time, temperature and gas on average about 0.00175% water 0.2 mm Hg water velocity, depending on the water partial pressure in partial pressure). In the diagram, the loss in yield of the inert drying gas is modified. In at different octane levels (severity of each case, the fresh catalyst is dewatered in such a way, operating conditions) due to the increasing water pressure that the water partial pressure in the inert drying amount in the circulating gas against the time in days carried out on contact with the dried catalyst, which for the moist circulating gas to act at a flow rate of 4.1 to kung on the yields (negative 41 Nm ³ / min./m ³ values of 1 to 3 mm Hg not above changes in the yields of C ₅ + reformate = Advancing under conditions regarding hive without a dryer). Temperature and water partial pressure in the drying

According to the invention, a treatment of all three gas, in which the surface of the catalyst preferentially water-releasing materials is expediently, by the 25 wise not substantially and generally not reduced to water release from all three sources to less than 50%,
The lowest practical value under the given conditions to reduce the yields achieved at pressures above 28.1 atmospheres. The naphtha feed may be of C ₅ + reformate from C ₆ + -Schwerbenzin with a by means of percolation through a salt, treatment with final boiling point in the range 121-132 ° C solid dehydrating agents, such as alumina or molecular 30 by drying the platinum group metal Reformiersieben , or also improved by distillation to a water catalyst to the above-described content of less than about 0.001 to 0.0015 percent by weight, and this generally applies to percent drying. The circulating gas is separated from for process implementation in the range between C ₅ - and heavier reformate components, the atmospheric pressure and 70.3 atmospheres or above. In the case of the cooled gas, if it contains more than 0.0001 to 35 production of C ₅ + reformate with an octane number of 0.0005% water at 14.05 atmospheres, that is, if it is from 109 to 111 (R + 3 cm ³ ) from a C ₅ -193 ° C water partial pressure above 0.01 to 0.06 mm Hg heavy gasoline is, even if at pressures not above 28.1 atmospheres, is worked according to any conventional method, the operating time between dried, substantially increased, for example, by bringing it into contact with regenerations.
Molecular sieves, alumina or the like, namely up to 40. In general, the platinum groups are dried with a moisture content of not more than 0.0001 volumetall reforming catalyst by contacting a volume percent at 14.05 atmospheres, ie a water partial gene of the catalyst with a Inert gas, such as nitrogen pressure of not more than 0.01mm Hg for a substance, hydrogen or exhaust gas with not more than 50% total pressure of 14.05 atmospheres. of oxides of carbon and a water content

The drying or conditioning of fresh 45 above a partial pressure of 100 mm Hg, in the case of a catalyst, is preferably carried out by not using temperatures below 371 ^° C. The temperature of the conditioned catalyst at 232 ^° C. is a stream of drying gas corresponding to the decrease of 400 volumes of hydrogen per Hour and per of the water partial pressure in which the catalyst is exposed from the reaction volume until the gas flowing out of the water zone increases gradually. Example partial pressure in the outflowing gas from the reaction mode, the temperature of the drying gas sub-zone is not higher than about 20 mm Hg. (The hydrogen entering the reaction zone at half a temperature of 371 ° C until the partial pressure of water is - if less is required for the gas flowing out of the reaction zone - preferably to about 0.0001% water than 100 mm Hg, e.g. 50 mm Hg, is then dried on). If the water partial pressure in the outflowing gas (point A in 55 to the water partial pressure in the outflowing gas F i g. 1) does not exceed 20 mm Hg, the temperature is less than when the water partial pressure is ^{increased from 399 0} C and kept at this temperature 50 mm, for example 10 mm Hg, then the temperature of the gas and thus the temperature of the catalyst further increased to 427 ° C and at this temperature the lysatorbettes increased to 371 ⁰ C and kept at 371 ⁰ C until the partial pressure of water in the flow stopped, until the water partial pressure in the outflowing gas does not exceed 10 mm and, for example, 5 mm Hg gas (points in FIG. 1) 5 mm Hg. ⁶ ° and finally again to at least 482 ° C. The temperature of the gas is then increased to 482 ° C, but not higher than about H ⁰ C below and held at 482 ° C until the water temperature at which one Catalyst damage partial pressure in the outflowing gas (points in Fi g. 1) occurs through the action of heat, ie the temperature does not exceed 1 mm Hg. According to this, in which the catalyst is irreversibly inactivated only by the action of heat in general, the moisture content of the catalyst 65. The temperature of the drying gas, low enough to carry out dry reforming at 14.1 atmospheres, is maintained at at least 482 ° C, provided that the feed is a heavy to partial pressure of water in which the gasoline reaction zone leaves the reaction zone with no more than about 0.0013 weight percent Gas is no more than 1 to 3 mm Hg.

ί3

In Fig. 1 is a system for reforming heavy gasoline at a low level in a schematic manner Reactor pressure, e.g. B. 14.1 atü, shown.

The reactors R ₁ , R ₂ and R ₃ with the reference numerals 7, 12, 17 are filled with the amount of fresh catalyst that is required to produce a suitable flow rate of the liquid, based on the catalyst volume, ie a space flow rate as they , is necessary for the minimum steam inlet temperature at which the heavy gasoline to a C ₅ + first reformate with the desired octane (leaded) can be reformed. For example, a plant for the treatment of 1590 m ^{3 of} heavy gasoline per day at an hourly space flow rate of the liquid of 1 volume is ^{filled with a total amount of 46.2 t, corresponding to 61.4 m 3 of} catalyst. With the valve 2 in the pipeline 1 closed and the valve 31 in the pipeline 23 closed, the system is evacuated to about 0.135 at = 125 mm Hg. Then an inert gas, e.g. B. nitrogen, introduced into the system through a pipe 27 (open valve 32) in order to flush out the air remaining in the system through a pipe 29. Once the concentration of oxygen in the inert gas is no greater than about 1%, the inert gas is replaced with hydrogen or a gas containing hydrogen. The hydrogen or the hydrogen-containing gas is circulated by means of a compressor 26, the valves 2, 32 and 30 being closed and the valve 31 being opened. In the present case, the temperatures of the circulated hydrogen-containing gas, i.e. the drying gas, are then preferably increased to about 232 ° C. and between about 2700 and 270,000 Nm ^{3 of} hydrogen per hour through the ovens and reactors, the separator and the dryer. The temperature of the separator 21 is maintained at 21 ° C. or below to reduce the load on the dryers. The lower the temperature in the separator, the more water is condensed in the separator 21 and the less water has to be removed by the dryer. Separator temperatures below about 21 ^° C. are to be preferred in connection with fixed bed dryers. The dehydration of the catalyst in the presence of the drying gas is continued until the water partial pressure in the drying gas at the vapor outlet of the reaction zone is not more than about 1 to 3 mm Hg, if the catalyst to be conditioned with a drying gas of a water partial pressure not exceeding 0.06 mm Hg in a Flow rate of about 300 to 3000 Nm ^{3 of} drying gas per hour and ton of catalyst corresponding to 4.1 to 41 Nm ^{3 of} drying gas / min. / M ^{3 of} catalyst is brought into contact.

The advantages by drying the platinum group metal reforming catalyst in the manner described above and reforming of heavy gasoline, especially the C ₆ -121 ° C fraction, atmospheres gauge at low pressures in the range of atmospheric to 28.1, preferably 7.0 to 21 . This includes an initial operating period, a regeneration and a second operating period; during the periods of operation C was prepared ₅ + reformate having an octane number 109-112 (leaded). The two operating periods each lasted about 3 months.

Input material:

C _e -121 ° C fraction one
Mid-continent heavy fuel

Paraffins 51.2 percent by volume

Olefins 0 percent by volume

Naphthenes 45.7 percent by volume

Aromatics 3.1 volume percent

100.0 percent by volume

Catalyst: unused

Platinum 0.61 percent by weight

Chlorine 0.7 percent by weight

Carrier: clay

Catalyst treatment in conditioning
Drying gas: hydrogen

temperature
⁰ C Space flow velocity
Nm ³ drying gas / h / m ³
catalyst Time
hours 232
510
515 268 to 482
268 to 482
2880 to 4400 2
2
3

Source of the in the reaction zone Moisture content introduced water mm Hg Heavy fuel (0.0015 percent by weight H ₂ O) 0.08 Circulating gas (0.0001 percent by volume) 0.01 (0.001 percent by volume) 0.11 Conditioned catalyst ... <3 mm at 482 ° C Pressure in the reaction zone, atm 14.05

Reforming conditions:

Steam inlet temperature Room flow Water partial pressures,
undried circulating gas Octane number RON at
Addition of 3 cm ³ Operating time speed,
Volume of liquid per Tetraethyl lead ⁰ C Volume catalyst mm Hg gas Days 515 and hour 0 515 0.8 - 111.7 1 515 0.8 22nd 111.0 10 515 0.8 38 * 110.5 30th 515 0.8 37 ** 109.2 60 527 0.8 - 109.2 90 0.8

Water surge after 29 days.

** Water surge after 53 days.

(Continuation)

Steam inlet temperature Room flow Water partial pressures,
undried circulating gas Octane number RON at
Addition of 3 cm ³ Operating time speed,
Volume of liquid per Tetraethyl lead ⁰ C Volume catalyst mm Hg gas Days and hour Regenerates 515 - - 0 515 0.8 150 112.4 1 515 0.8 30th 111.4 10 515 0.8 22nd 110.8 30th 515 0.8 19th _ 109.3 60 523 0.8 - 109.2 90 0.8

The drying gas used is preferably hydrogen or a gas containing hydrogen with at least 50 percent by volume hydrogen and the remainder C ₁ - to C ^ hydrocarbons. In the dry reforming is expediently at pressures of 3.5 to 28.1 atmospheres and preferably 10.55 to 21.1 atmospheres and temperatures of at least 482 "C, but not higher than 11 ° C below the catalyst inactivation temperature in the presence of not more than 0.2 and preferably 0.1 to 0.2 mm Hg water partial pressure, measured in the vapors flowing out of the reaction zone, is used Percent by weight or above and the concentration of chlorine and / or fluorine within the limits of 0.1 to about 0.8 percent by weight, alumina present can contain up to 45 percent by weight of silica.

The following is a preferred procedure involving conditioning the catalyst in a device according to FIG. 1 described.

The system is evacuated to about 0.135 at -125 mm Hg via a pipe 29 and with an inert gas flushed out such as nitrogen or exhaust gas until the oxygen concentration in the outflow from the reactor 17 Gas is not higher than about 1%. Thereafter, the valve 30 is closed and the valve 31 is opened. Then the drying gas is introduced into the plant through the pipe 27. When the pressure is in the system is between about 1.76 and 14.05 atm, the valve 32 is closed and the drying gas is circulated by means of a compressor 26 and in the cooler 19 is cooled to at least 21 ° C. by means of a coolant, usually water. Partly dried drying gas is mixed with a sufficient amount of a solid absorbent such as brought into contact with a 4 to 5 angstrom molecular sieve, clay or another desiccant, so as to lower its moisture content to a partial pressure of water not above about 0.01-0.06 mm Hg.

The circulating drying gas is initially heated to 232 ° C. in the heaters 5, 10 and 15. The temperature is maintained below about 371 ° C until the partial pressure of water in the material flowing out of reactor 17 is no higher than about 100 mm Hg, then increased to about 371 to 385 ° C until the partial pressure of water in the material flowing out of reactor 17 is increased Material is no higher than about 35 mm Hg, and then increased to about 427 to 441 ⁰ C and held in this range until the water partial pressure in the material exiting the reactor 17 is no greater than about 10 mm Hg. Thereafter, the temperature of the drying gas is increased to about 510 ° C. and held at this level until the water partial pressure in the gas flowing out of the reactor 17 is not more than 1 to 3 mm Hg. During this drying of the catalyst, the drying gas is circulated through the reactors ^{at a space flow rate of about 4.1 to 41 Nm 3} / min./m ^{3 catalyst.} In the last conditioning period, the water partial pressure in the circulating drying gas leaving the dryer 24 is not greater than 0.06 mm Hg Hg is - the temperature of the drying gas gradually 371-385 ° C according to the decrease of the water partial pressure in the effluent material to be increased, and to an extent of about 0.8 to 1.0 ⁰ C per 1 mm Hg decrease in water partial pressure in the effluent Material.

The catalyst is now conditioned for dry reforming when the concentration of water in the heavy gasoline feedstock does not exceed 0.0015 percent by weight and the concentration of water in the circulating gas is not greater than 0.0001% at 14.05 atm. The water in reactors 7, 12 and 17, that originates from the catalyst, the heavy fuel used and the circulating gas, is then preferably within the limit of 0.1 to 0.2 mmHg, measured at the point in the outlet line of the Reactor 17. Now the drying gas, provided it is hydrogen or the aforementioned hydrogen-containing Gas was different from hydrogen or a hydrogen-containing gas Type in which the water partial pressure is not higher than in the drying gas emerging from the dryer 24, replaced. The pressure in the system is increased to the operating pressure, in this embodiment to less than 28.1 atmospheres and for example 14.1 atm. Simultaneously with the replacement of the main part or the total amount of that of hydrogen or Hydrogen-containing gas, different drying gases, are the temperatures at the vapor entry points the reactors 7, 12 and 17 - if necessary - lowered to the operating temperatures and heavy fuel from a supply point, not shown, by means of a pump, not shown the pipe 1 (open valve 2) is inserted into the pipe 3; the heavy fuel charge mixes there with the circulating gas to form a mixture with a hydrogen-heavy gasoline

Molar ratio between about 0.5: 1 and 25: 1 and preferably between about 3: 1 and 10: 1. For example, a heavy gasoline charge is added. Whose arsenic content 2 x 10- ⁹ and S whose lead content ■ 2 10 ~ ⁹ does not exceed (C "-121 ° C Mid-Continent-naphtha), the nitrogen content of 0.0001%.

The feed mixture is in the coil 4 of a furnace 5 to the reaction temperature the reforming heated, flows through a pipe 6 to the reactor 7 and down in this its steam outlet and then through a pipe 8 to the pipe coil 9 of a furnace 10; here will the material flowing out of the first reactor back to a reaction temperature suitable for the reforming heated up. This temperature can be the same, higher or lower than the temperature on Vapors enter the reactor 7. The reheated material flows through a pipe H and in a downward direction through the reactor 12. The mixture flowing out of this second reactor flows through so a pipe 13 to the heating coil 14 of a furnace 15, and is there again on a for reforming heated to a suitable reaction temperature; this temperature can be the same, higher or lower than that Reaction temperatures at the entry points of the as Reactors 7 and 12. The mixture then flows through conduit 16 and down through reactor 17. The reaction mixture flowing out of this third reactor flows through a pipe 18 to a Cooler 19.

In the cooler 19, the reaction mixture flowing out of the third reactor is cooled to a temperature at which water and C ₄ and higher hydrocarbons condense, preferably to about 21 ^° C., in order to control the load on the dryer. Maintaining lower cooler temperatures depends on the local conditions, but the lower load on the dryer usually does not outweigh the increased costs of cooling to noticeably lower temperatures. The cooled reaction mixture flows from the cooler 19 through a pipe 20 to the liquid-gas separator 21, where the C ₄ and heavier hydrocarbons and water are separated from the hydrogen and the C ₁ to C ₃ hydrocarbons.

The C ₄ and heavier hydrocarbons are drawn off from the separator 21 through a pipeline 22 and flow to appropriate devices for the final completion of the reformate, such as stabilization, fractionation or the addition of additives. The water flows from the separator 21 through a pipe 28 into a waste line.

The hydrogen and the C ₃ and higher hydrocarbons form the circulating gas. This flows from the separator 21 through a pipe 23 to the dryer 24 (open valve 31). If the volume of circulating gas is greater than the volume required to maintain the hydrogen / heavy gasoline molar ratio, part of the circulating gas is diverted into the main gas line of the refinery to carry out other work processes.

The water partial pressure in the gas leaving the separator at 21 ° C. is usually between about 15 and 20 mm Hg. The dryer 24 comprises a plurality of drying vessels, some of which are connected to the gas stream to be dried and some to the regeneration stage of the operating cycle. The reduction of the water partial pressure in the circulating gas from 20 to 0.01 mm Hg requires contacting with about 5 to 20 kg of a molecular sieve material (4 to 5 angstroms) per 1000 Nm ^{3 of} the circulating gas to be dried. The dried circulating gas with a water partial pressure of 0.01 to 0.06 mm Hg flows through a pipe 25 to the suction side of the compressor 26, is there again compressed to a pressure slightly above the pressure prevailing in the reactor 7 and then flows back through the pipe 3 to the heating coil 4 in the furnace 5. At some point in the pipeline 3 between the compressor 26 and the heating coil 4, the heavy gasoline is mixed with the dried circulating gas to form the charge. The dryer 24 can also be arranged behind the compressor 26, ie between the compressor 26 and the furnace 5.

Claims (5)

Patent claims: 1. Process for reforming heavy gasoline at pressures between atmospheric pressure and 70.3 atmospheres using a platinum group reforming catalyst and adjustment of the Water vapor partial pressure, characterized in that the water vapor partial pressure is set in the reaction zone so that that the withdrawing reaction mixture has a water vapor partial pressure of at most 0.2 mm Hg, measured at 14.05 atmospheres. 2. The method according to claim 1, characterized in that one is a heavy gasoline with a Water content of not more than 0.0015 percent by weight used. 3. The method according to claim 1 or 2, characterized in that there is hydrogen-containing Gas with a water vapor partial pressure of 0.06 mm Hg or less, measured at the entrance to the Reaction zone, is used. 4. The method according to any one of claims 1 to 3, characterized in that a catalyst is used which has a surface area of at least 200 m ² / g and a moisture content which is not more than 1.1 percent by weight greater than the moisture content of the catalyst Firing is at 1250 ⁰ C for 48 hours. 5. The method according to any one of claims 1 to 4, characterized in that one with a Drying gas and increasing temperature, but not exceeding 538 ° C Catalyst used. Considered publications:
German Auslegeschriften No. 1 006 104, 1 089 902. For this purpose 2 sheets of drawings 509 759/509 12.65 © Bundesdruckerei Berlin