DE1257120B - Process for controlling the production of hydrogen by catalytic cracking of a hydrocarbon feed stream - Google Patents

Description

GERMAN

PATENT OFFICE

EDITORIAL

German class: 12 i - 1/20

Number: 1 257 120

File number: U 8642IV a / 12 i

Filing date: January 23, 1962

Open date: December 28, 1967

The invention relates to a method for controlling the production of hydrogen by catalytic Cracking a hydrocarbon feed stream in one with only two exclusion zones a coke extraction system operating from the process, in particular the invention relates the implementation of such a process in a fluidized bed system using Natural gas, methane or other hydrocarbons. In common fluidized bed conversion systems such as it is used for catalytic cracking of gas oil for upgrading cracked gasoline It is common to provide heat control on the reactor by applying the heat from the hydrocarbon feed stream with heat exchangers or preheaters and the circulation speed of the hot catalyst between the regenerator and the reactor varies. Run in the catalytic cracking of oils with the aim of a gasoline yield the fluidized bed cracking units as "thermally balanced" units without much difficulty. at the cracking of methane to hydrogen and coke, however, the operation is highly endothermic and requires a high temperature, generally above 650 ° C. It is therefore necessary that from the carbon, generated in the cracking reaction, available heat in a particularly favorable Take advantage of dimensions. In a continuous fluidized bed system, carbon is found in the regeneration zone burned to yield carbon monoxide and carbon dioxide and the catalyst particles for that Return to the reaction zone to heat up. Of course, it is undesirable and also uneconomical to have additional Having to burn fuel in the regeneration zone, especially when the regeneration stage is in operation can be to the necessary heat from the coke forming in the reaction zone deliver.'

In a process for the production of synthesis gas by the separate production of hydrogen and carbon monoxide with subsequent mixing of the two gases in a molar ratio corresponding to the synthesis gas, it is known to work in a system with only two conversion zones with the exclusion of coke removal and the endothermic heat of the conversion of the Hydrocarbon in hydrogen and carbon at a temperature above 650 ° C from a catalyst regeneration zone to the reaction zone by means of a stream of heated catalyst particles to conduct the carbonized catalyst particles from the reaction zone to the regeneration zone and therein by methods for controlling the production
of hydrogen through catalytic cracking
a hydrocarbon feed stream

Applicant:

Universal Oil Products Company,

Des Piaines, JH. (V. St. A.)

Representative:

Dr. H.-H. Willrath, patent attorney,

Wiesbaden, Hildastr. 32

Named as inventor: 20th Claimed priority (V. St. A.) Jack Bernard Pohlenz, V. St. v. America from Arlington Heights, JIl. 26th January 1961 (85 154)

Combustion of carbon in oxygen-containing gas to reheat. When aiming, syngas Of course, it is important to obtain essentially pure carbon monoxide without it To obtain carbon dioxide, and one must consequently control the process so that during the combustion of the carbon only carbon monoxide is produced. An increase in the splitting temperature by increasing the oxygen supply is to be avoided.

In contrast, the invention is based on the finding that when operating a fluidized bed system for hydrogen generation with a catalyst vortex, the ratio of carbon dioxide to carbon monoxide in the regenerator exhaust gas stream varies slightly and arbitrarily within certain limits of carbon deposition on the catalyst particles, and the ratio of carbon dioxide to the total carbon dioxide formed varies can be regulated or controlled in response to certain levels of carbon retained on the regenerated catalyst. In other words, with a practically constant circulation speed of the catalyst particles between the zones with simultaneous generation of an exhaust gas stream from the generator at a practically constant temperature, the ratio of CO ₂ : CO can develop.

709 710/566

3 4

Speaking of fluctuating values of the catalytic gas and coke, lead in the reaction zone. if

carbon retained by satellite particles, however, as in the present case, the gap

will. processing of light hydrocarbons, e.g. B. methane,

This object is according to the invention thereby acts on hydrogen and coke, which of course with solved that during the incomplete incineration 5 higher temperature than the recovery of cracking of the carbon from the catalyst particles takes place gasoline, so the temperature increase for and during the supply of heated carbonaceous ones the hydrogen formation by means of high cycle catalyst particles with a practically constant flow rate of the heated catalyst particles speed to the reaction zone, the oxygen can still be promoted by the fact that on the supply to the regeneration zone by regulating the quantity of catalyst particles in the regeneration zone is increased or decreased. The invention provides higher carbon content up to 8% allows a fine regulation of the hydrogen production, in order to increase, if necessary, by further oxidation by increasing the volume ratio of carbon monoxide or carbon dioxide the necessary from carbon dioxide to total carbon oxides in endothermic heat supply during the tempedem Regeneration exhaust gas and an increase in the temperature of the regenerator exhaust gas practically constant The temperature of the regenerated catalyst remains at one.

substantially constant higher value causes if one changes in the ratio of

if a higher heat supply to the reac- carbon dioxide to carbon monoxide in the regeneration

tion zone is desired, and on the other hand the zone is created, it is necessary to add the amount

Oxygen supply to the regeneration zone to change to a abducted oxygen. An increased one

Speaking reduction of this volume ratio - amount of oxygen leaves the ratio of CO ₂ to CO

nisses in the exhaust gas and the temperature rise to a higher desired value and

of the regenerated catalyst to an essentially- at the same time results in a lower residual carbon

lichen constant lower value causes when substance deposits on the regenerated catalyst part

Heat supply to the reaction area. But if the regeneration level is balanced

is. and a catalyst stream is desirable

For the sake of stability, it should also be mentioned that increased temperature should result in the

in a known method for generating amount are somewhat reduced, but is on a

large pieces of hard coke with simultaneous water greater height than previously required

Extraction of material was the addition of a special difficulty to the earlier regeneration company with its

Oil feed with high Conradson content- lower carbon dioxide production and with a

Coal to the somewhat smaller amount of carbon extracted with hydrocarbon gas in the

Coke stream is known, the reaction yielding in directed catalyst stream. The Invention

a zone of high flow velocity ground therefore sees two embodiments for the

follows and from the product stream hydrogen from the regulation of the increase or decrease

Coke is separated. Since the coke is the product of the oxygen supply to the regeneration zone: In

is recovered, is also not a regeneration zone in front of a fall, it is done with the help of the measurement of the

act. associated increase or decrease in

Finally, according to an older proposal, there is a volume ratio of CO ₂ : CO + - CO., In which the coverage of the gaseous hydrocarbons to be applied during the thermal splitting of exhaust gas that is withdrawn from the regeneration zone, in the other case with the help of the measurement of the heat Cycle of carbon through an associated increase or decrease in the coal heating device and a cracking reactor under the amount of material that is kept in the regenerated catalyst partial combustion of the carbon in a.

Fluidized bed in that the circulating coke 45 The invention is explained in more detail below with reference to the heating device from top to bottom with reference to the drawing,
go through and part of the incineration F i g. 1 shows schematically a catalyst vortex while the amount of air required for carbon in the layer system

Coke fluidized bed, the rest, however, above this Fig. 2 in a curve the relationship between

Layer in the falling coke particle stream 50 carbon content on the regenerated catalyst

will lead. According to this older method, however, and the ratio of carbon dioxide to total carbon

a system with two conversion zones of oxygen oxides in the regeneration zone is not explained,

turned, and in addition, coke is sold as a product. 1 is natural gas through line 1,

drawn. Methane or other light hydrocarbon

In a preferred embodiment of the invention, which is suitable for catalytic cleavage, a carbon content in the range of 1 hydrogen and coke is suitable. The hydrocarbon up to 8% on the heated catalyst particles, the feed will go with heated catalyst particles from the regeneration zone to the reaction zone, mixed, which are introduced from line 3 with control valve 4 during the supply of a normally gas-fed; the resulting fluidized hydrocarbon feed to the reaction mixture is maintained through riser 2 down into the zone. In the usual catalytic reaction chamber 5 by a grate, for. B. a cracking of gas oil in fluidized bed systems to the perforated plate 6, initiated so that a uniform recovery of an improved cracked gasoline is dense fluidized bed 7 in the lower part of the chamber is regularly maintained in the regeneration zone practically the mer 5, in which all the carbon is removed or at least on 65 Conversion of the hydrocarbon ^{stream is reduced by less than 0.5 1} Vo, because higher residual amounts are produced. If the entire hydrocarbon wall carbon content leads to poor product distribution in the riser as a reaction zone in front of it, in particular the production of larger amounts and no dense phase with a level in a

5 6

the weathered reaction zone is maintained, a temperature increase in the reactor is required

the product flow from the riser 2 directly the slide valve 4 is opened further, so that a

discharged in particle separators, which with their larger amount of hot catalyst particles in the

Particle return lines directly to the mix with hydrocarbon flows through line 2,

generation zone are connected. 5 If, conversely, a lower temperature in the

In general, the conversion is desired around the reactor, then the slide valve

650 to 925 ° C. The heated catalytic valve 4 is throttled.

satorteilchen therefore leave the regeneration zone

with an elevated temperature of about 675 to reactor to regenerator by means of slide valve 12

980 ° C. ίο automatically adjusted in line 11 in order to

In this fluidized bed system, the operating table constant level within the reactor 5 pressure is only slightly above air pressure, but can be maintained. The mirror control sensors 28 and sufficient to achieve the desired particle cycle 29 are connected to the mirror control device LRC. In practice, operating pressures are bound, which in turn is connected to the automatic control less than 3.4 atmospheres and mostly in the range of 15 valve 12. On a system applied at about 0.68 to 2 atm. the dense phase 7 and the reaction chamber 5

In the upper section of the reaction chamber 5 will not be present, the mirror control

The catalyst particles in the cyclone 8 are removed from the LRC and the slide valve 12 also continues.

tiennt and be left on the plunger 9 in the density. In such a system the

Fluidized bed 7 steered, while the gas flow ao light phase flow in the riser 2 immediate

is discharged through line 10. The present bar to the particle separator, and its immersion

Operation results in approximately equilibrium conversion thigh communicates directly with the density

in hydrogen, so that the only other material regenerator fluidized bed 13 or z. B. with the air

of a significant amount in the gas mixture from the line to the regenerator.

Methane consists of very little at most 25 Preferred catalysts should be able to contain carbon oxides. Separated catalyst to withstand high conversion and regeneration temperatures with a coke deposit and perhaps in the order of 980 ⁰ C, some entrained coke from the fluidized such as alumina, silica-alumina or silica layer 7 through a discharge line 11 and a control acid —Magnesia, oxides of zirconium, titanium valve 12 to the regeneration chamber 13. 30 and the like, or mixtures of the above oxides

Oxygen-containing gas, e.g. B. air, is in the with an oxide of chromium, molybdenum or Vaunteren part of the regenerator 13 via a perforated nadium. Preferably, metals or metal pipe system 14 are introduced which is connected to the inlet line oxyde of group VIII of the periodic table for 15. Through the line 16 with which the most favorable hydrogen formation is needed, like the control valve 17, air goes to the compressor 18 and 35 nickel or cobalt compounds on silica - compressed air to the inlet line 15 and distribution inlet alumina. The size of the catalyst particles can be direction 14. The coke-containing catalyst particles are between 0.01 and 0.8 mm in diameter,
According to one embodiment of the invention, the air is treated in a dense fluidized bed 19 in the chamber 13 with the upward flow is located. The latter are regulated and controlled total carbon oxides which are separated in the cyclone 20 and converted into density. In Fig. 2, the carbon percentage phase 19 is plotted back logarithmically on the abscissa against the ratio by means of a plunger leg 21, while the exhaust gas flow, which contains a high percentage of CO ₂ to total carbon oxides per amount of carbon monoxide, is plotted through line 45 of the uniformly divided ordinate. As 22 is withdrawn with control valve 23 and can be seen in a coal from the curve is above about monoxydbrenner or boiler to carbon dioxide comparable 0.5 ⁰ O carbon of the catalyst is in particular burnt. above about 1%, a fairly straight line

Catalyst particles with a balance of carbon dependence between carbon content and percentage deposition decrease continuously from the lower 50 set of generated carbon dioxide in relation to geTeil of the regenerator 13 in an elongated Ab- generated carbon oxides. In a row strip section 24. This is used to remove operational tests in which a natural carbon oxide and other entrained gas flow with about 85% methane at increased temterial, that the conversion in the reaction zone temperature was broken, the regenerator gave a can interfere, by means of nitrogen or other inert 55 practically constant gasification and carbon degassing or reducing gas, which is down in the stripping distance from the catalyst particles, a practical sections 24 through line 25 and valve 26 a constant temperature in the light phase of the regulator will. Part of the hydrogen-containing generator at a catalyst temperature of 685 The duct flow can advantageously be used as a stripping agent up to around 691 ° C and a fairly constant cycle by going to line 25 and at 60 speed for the catalyst particles between stripping section 24 is branched off. The zones that look like. These results are in the following Catalyst particles are continuously compiled in the table. The different through line 3 and control valve 4 to riser 2, carbon values of the regenerated catalyst to then re-enter the reaction zone 5. given in percent by weight. The amounts of

A temperature sensor 27 inside the reac- 65 carbon dioxide and carbon monoxide relate

tor 5 is connected to a temperature controller that operates on the regenerator gas flow. The bottom row of

is connected to the control valve 4 and a table gives the percentage of CO ₂ in relation to

automatic slide valve actuated. When a CO r CO ₂ content in the exhaust gas.

Experiment No. 5 6

10

»/ Ο C

⁰ / o CO ₂

% CO

° / ο CO ₂ : CO + CO ₂

3.27 3.81 2.08 7.3 8.4 10.1 15.8 16.1 15.1 31.5 34.3 40.1

1.79 9.6 Π, 7

45.0

1.60 9.5

11.0

46.5

1.14 0.94 0.72 0.57 0.45 10.3 9.7 10.7 6.5 13.7 10.0 10.5 9.1 4.7 4.3 50.7 48.0 54.3 58.0 76.2

0.41 13.6

2.4
85.0

If the carbon content is kept below about 0.5%, the ratio of CO ₂ : CO rises sharply with the result that considerable heat can be generated. So if the exhaust gas outlet temperature is kept practically constant, there is inevitably an increase in the sensible heat of the catalyst particles, which leads to a greater heat input at a constant catalyst circulation rate. Above about 0.5% the change in carbon dioxide production is fairly constant, the latter decreasing as the carbon content increases, or vice versa.

When carrying out the controls, carbon content measurements can be carried out continuously or intermittently, and the carbon content can be controlled in accordance with such measurements. In other words, where the catalyst cycle rate is maintained at a practically high level and it is desirable to increase the temperature in the reaction zone without further increasing the catalyst cycle rate, the air or oxygen-containing flow to the regenerator can be adjusted so that temporarily a larger amount of carbon is gasified and a lower carbon content is achieved on the regenerated catalyst particles and, in addition, a greater combustion of CO to CO _{2 is} effected. This adjustment may require a variable modification in the air introduction insofar as there may be a temporary substantial increase in the oxygen demand, while a continuously only slightly increased amount of oxygen maintains the increased conversion of CO to CO ₂ . In other words: once the regeneration has deviated in order _{to provide a greater CO 2} production, the air can be adjusted in such a way that a stoichiometric and practically constant carbon gasification with the desired values of residual carbon and CO ₂ bonds results. Where less heat introduction into the reaction zone is desired, the regeneration stage can be controlled so that the carbon content is somewhat above that which prevailed. In other words, the introduction of air or oxygen to the regeneration zone is reduced to allow less carbon dioxide production and increased carbon monoxy production while at the same time increasing the carbon content on the regenerated catalyst particles.

In a continuously operating system, the amounts of carbon can be determined using

Claims (4)

Patent claims: 1. Method of controlling the production of hydrogen by catalytic cracking of a Hydrocarbon feed stream in one with only two exclusion zones a coke extraction from the process operating system in which the endothermic heat the conversion of the hydrocarbon to hydrogen and carbon at one temperature above 650 ° C from a catalyst regeneration zone to the reaction zone by means of a Is conducted stream of heated catalyst particles, the carbonized catalyst particles the reaction zone passed to the regeneration zone and therein by combustion of carbon in oxygen-containing gas are reheated, characterized in that during the incomplete combustion of the carbon from the catalyst particles and during the supply of heated carbonaceous catalyst particles at a practically constant flow rate to the reaction zone the oxygen supply to the regeneration zone by regulating the amount is increased or decreased. 2. The method according to claim 1, characterized in that a carbon content in the range from 1 to 8% on the heated catalyst particles passing from the regeneration zone to the reaction zone go while feeding a normally gaseous hydrocarbon feed to the reaction zone is maintained. 3. The method according to claim 1 or 2, characterized in that the increase or decrease in the oxygen supply to the regeneration zone with the help of the measurement of the associated increase or decrease in the volume ratio of CO ₂ : CO + CO ₉ in the exhaust gas from the Regeneration zone is withdrawn, is regulated. 4. The method according to claim 1 or 2, characterized in that the increase or decrease in the oxygen supply to the regeneration zone with the help of the measurement of the associated increase or a decrease in the amount of carbon contained in the regenerated catalyst will. of course
will. working sampling devices.
British Patent No. 883,751;
U.S. Patent Nos. 2,690,963, 2,805,177. Legacy Patents Considered:
German Patent No. 1 206 403. 1 sheet of drawings 709 710/566 12 67 Bundesdruckerei Berlin