WO2025031881A1 - Method and reactor assembly for pyrolyzing hydrocarbon-containing fluids, and reactor assembly - Google Patents

Abstract

The invention relates to a method and a reactor assembly at least for pyrolyzing hydrocarbon-containing fluids at least in order to generate at least hydrogen-containing fluids. The hydrocarbon-containing fluids are supplied to a reactor shaft of a reactor (1) in countercurrent with a fluidized bed of the reactor (1), said fluidized bed consisting of particles, wherein at least the particles of the fluidized bed and the hydrocarbon-containing fluids are heated to a defined temperature ranging from 800-1600 °C, and particles of the fluidized bed are introduced at a reactor head (2) and are discharged at a reactor sump (3). In a method in which instabilities of the electric heat input can be prevented during a methane pyrolysis for producing hydrogen and pyrolytic carbon, the particle size of the particles of the fluidized bed are conditioned after discharging the particles from the reactor sump (3) such that the particles subjected to the conditioning process are at least partly introduced at the reactor head (2), and the particles introduced at the reactor head (2) have a uniform particle size x1, said uniform particle size having a grain size range.

Description

Description

Process and reactor arrangement for the pyrolysis of hydrocarbon-containing fluids and reactor arrangement

The invention relates to a method at least for the pyrolysis of hydrocarbon-containing fluids at least for the production of at least hydrogen-containing fluids, wherein the hydrocarbon-containing fluids are fed to a reactor shaft of a reactor in counterflow to a moving bed of the reactor consisting of particles, wherein at least the particles of the moving bed and the hydrocarbon-containing fluids are heated to a defined temperature in the range between 800-1600 °C, wherein particles of the moving bed are introduced at a reactor head and wherein particles of the moving bed are discharged at a reactor sump. The hydrocarbon-containing fluids are introduced into the reactor from below and the particles are introduced by gravity from above.

In addition, the invention relates to a reactor arrangement at least for the pyrolysis of hydrocarbon-containing fluids at least for the production of at least hydrogen-containing fluids with a reactor, wherein the reactor has a reactor shell and a reactor shaft arranged within the reactor shell, wherein the reactor has a reactor head and a reactor sump, wherein the reactor head and the reactor sump each have at least temporarily closable feed openings and discharge openings through which at least fluids or solids, in particular particles, are to be introduced or discharged, so that in order to produce a moving bed, particles are at least temporarily continuously introduced into the reactor shaft through the reactor head.

The thermal pyrolysis of methane as the simplest hydrocarbon-containing fluid is a strongly endothermic reaction, which kinetically and thermodynamically prefers a temperature range of 1000-1500 °C. The equilibrium shifts to the reactant side with higher pressure. For economic reasons, a pressure of between 5 and 15 bar, preferably between 10 and 25 bar, is selected. In addition to hydrogen, the thermal cracking also produces pyrolysis carbon, which is an additional valuable product. If carbon particles are present, the methane pyrolyses on the particles. The particle sizes after deposition can be adjusted by the size of the particles present and the specific carbon deposition. This means that the carbon can be formulated in the reaction step. Electrical heat input is particularly suitable for providing the reaction enthalpy. The reactor is resistance-heated by at least one pair of electrodes arranged in the particle bed.

The electrical current flows over the carbon bed and dissipates into thermal energy due to the electrical resistance of the particle bed. The electrical resistance results from the contact points between the particles or the small transfer surfaces, while the carbon particles themselves have a high electrical conductivity. For a homogeneous heat input into the heating volume, a homogeneous electrical resistance over the entire cross-sectional area of the reactor is required. If paths with different electrical resistance occur, the electrical current flows preferentially in the areas of low electrical resistance. As a result, the conversions in these areas are higher due to higher temperatures. The deposits of the pyrolytic carbon further reduce the resistance along these preferred paths. The consequence is the formation of hotspots. Such a concept is shown, for example, in the publication WO 2020 244 803 A1.

The invention is therefore based on the object of specifying a reactor and a method in which instabilities in the electrical heat input during methane pyrolysis for the production of hydrogen and pyrolysis carbon can be prevented. The adjustment of the particle size distribution is crucial for stabilizing a homogeneous heat input. This object is achieved in the present invention by the features of the characterizing part of patent claim 1, firstly in that the particle size of the particles of the moving bed are conditioned after being discharged from the reactor sump, that the particles subjected to conditioning are at least partially introduced at the reactor head and that the particles introduced at the reactor head have a uniform, average particle size x1, wherein the uniform particle size has a grain band.

The grain band is a particle size distribution or a grain size distribution. Strictly speaking, it is not possible to produce a uniform particle size. The particle size varies within a grain size distribution. In this case, the grain band is narrow, which means that the scatter of the grain size distribution is small compared to the particle diameter. The particle sizes of the particles introduced at the reactor head are therefore very close to one another, so that one can speak of a uniform particle size.

Preferably, the uniform, average particle size x1 is in the range of 2 - 4 mm, particularly preferably in the range of 2.5 - 3.5 mm. The uniform, average particle size corresponds to the maximum of the grain size distribution.

The grain band preferably corresponds to a scatter of +/- 0.75 mm around the uniform particle size x1, wherein at least 90 wt.% and preferably at least 95 wt.% of the particles have a diameter within the grain band.

The parameters of the grain size distribution, such as the uniform, average particle size and the grain band, can be determined, for example, by means of a sieve analysis. Grain size fractions can be formed using stacked sieves and a histogram of the grain size distribution can be created. The maximum of the grain size distribution corresponds to the average, uniform particle size. Sieves with openings the size of the grain band boundaries can be used to separate the particle fraction with the uniform particle size x1, which includes the corresponding grain band. The weight proportion of the particle fraction in the total sample can then be determined by weighing. Details of the sieve analysis particulate materials can be found, for example, in the IFDC S-107 standard of the International Fertilizer Development Center (IFDC).

A moving bed is a bed of granules or particles. It would be conceivable that the entire cross-section of the reactor shell is filled. However, it is also conceivable that the moving bed has a ring-shaped cross-section. By continuously discharging the particles at the reactor sump, the moving bed moves steadily downwards. The particles can be removed and replaced or fed back into the reactor chamber at the reactor head. In this case, the reactor chamber is understood to mean the interior of the reactor including any inlet and outlet zones.

Conditioning can, for example, involve sieves in a screening device and/or a mill in a crushing device. In this way, particles of the desired size can be obtained. This minimizes the risk of hotspots forming in the moving bed of the reactor, which prevent even heat distribution. Furthermore, blockages caused by bridging can be minimized.

Various well-known conveying devices can be used for conveying. In addition to conveyor belts and bucket elevators, ventilation or gas-powered conveying devices are also conceivable.

Further preferred embodiments of the invention result from the remaining features mentioned in the subclaims.

In a first embodiment of the method according to the invention, it is provided that the conditioning comprises at least one classification or at least one comminution of particles. By means of the classification, at least two partial quantities of the original solid mixture can be obtained. By means of the comminution, the particle size distribution can be adjusted accordingly. For this purpose, in a further embodiment of the method according to the invention, it can be provided that particles larger than x1 from a first classification are crushed in a crushing unit, that the crushed particles are classified in a second classification, wherein after the second and/or first classification, particles with a size of x1 are at least partially fed to the reactor. In this way, the grain band of the particles that are fed into the reactor can be made narrower. Particles can be crushed accordingly and fed back into the reactor with the size x1.

Additionally or alternatively, in a further embodiment of the method according to the invention, it can be provided that particles with a size greater than x1 which leave the comminution unit are at least partially returned to the comminution unit after the second classification.

In an alternative embodiment of the method according to the invention, it is provided that the particles from the reactor sump are fed to a comminution unit and at least partially crushed, wherein the crushed particles are classified in a first sieve and wherein particles with a size of x1 are fed to the reactor, characterized in that the particles smaller than x1 and larger than x1 are at least partially discharged from the process and wherein particles with a size of x1 can also be partially discharged.

In addition, in a further embodiment of the invention, it can be provided that particles with a size greater than x1 which leave the comminution unit are at least partially returned to the comminution unit after classification.

In a further alternative embodiment of the method according to the invention, it is provided that the particles are classified in a first sieve after being discharged from the reactor and that particles with a size of x1 are at least partially fed to the reactor head, particles smaller than x1 are discharged from the process and particles larger than x1 are crushed in a crushing unit, characterized in that the particles from the crushing unit are at least partially returned to the first sieve. The aforementioned object is also achieved by a reactor arrangement at least for the pyrolysis of hydrocarbon-containing fluids at least for the production of at least hydrogen-containing fluids with a reactor, wherein the reactor has a reactor shell and a reactor shaft arranged within the reactor shell, wherein the reactor has a reactor head and a reactor sump, wherein the reactor head and the reactor sump can each have at least one at least temporarily closable feed opening and discharge openings through which at least fluids or solids, in particular particles, are to be introduced or discharged, so that in order to produce a moving bed, particles are at least temporarily continuously introduced into the reactor shaft through the reactor head. It is provided that the reactor is in an operative connection with the reactor sump with a first conditioning. The conditioning can be, for example, sieves in a sieving device or a mill in a comminution device.

The device for conditioning particles preferably comprises at least one classifying device which is designed to classify particles taken from the reactor sump and to separate a particle fraction with a uniform particle size x1, which has a grain band, for return to the reactor head. The classifying device can be designed, for example, as a sieve device. In the simplest case, the sieve device can comprise two sieves with which particles outside the grain band, i.e. those with a diameter larger or smaller than the uniform particle size x1, can be discharged.

The uniform particle size x1 is preferably in the range of 2 - 4 mm, particularly preferably in the range of 2.5 - 3.5 mm. The grain band preferably corresponds to a scatter of +/- 0.75 mm around the uniform particle size x1, with at least 90% by weight and preferably at least 95% by weight of the particles having a diameter within the grain band. The reactor arrangement can be designed to carry out a method according to the invention. The above statements regarding the method according to the invention also apply accordingly to the reactor arrangement according to the invention.

In a first embodiment of the reactor arrangement according to the invention, it is provided that the reactor is operatively connected to a first screening device or to a comminution unit. At least two partial quantities of the original solid mixture can be obtained by means of the screening device. The comminution unit can crush particles whose particle size is larger than a desired size, so that a narrow grain band can be achieved in the particle distribution. In this way, a more stable reactor operation can be achieved, which can improve the handling of the reactor.

For this purpose, in a further embodiment of the reactor arrangement according to the invention, a first classification can be operatively connected to a comminution unit such that particles larger than x1 from the first classification can be comminuted in the comminution unit, and the comminution unit can in turn be operatively connected to a second classification such that the comminuted particles can be classified in the second classification, wherein the second and/or first classification is operatively connected to the reactor such that particles with a size of x1 can at least partially be fed to the reactor. In this way, the grain band of the particles that are fed into the reactor can be made narrower. Particles that are initially larger than x1 can be comminuted accordingly and at least partially fed back into the reactor with the size x1.

Additionally or alternatively, in a further embodiment of the reactor arrangement according to the invention, the second classification can be in a further operative connection with the comminution unit such that particles with a size greater than x1 which leave the comminution unit can be at least partially returned from the second classification to the comminution unit. In an alternative embodiment of the reactor arrangement according to the invention, it is provided that the reactor sump is operatively connected to a comminution unit in such a way that the particles from the reactor sump can be fed to a comminution unit and partially comminuted, wherein the comminution unit is operatively connected to a first sieve in such a way that the particles can be classified in the first sieve and wherein the first sieve is operatively connected to the reactor in such a way that particles with a size of x1 can be fed to the reactor, characterized in that the particles smaller than x1 and larger than x1 are at least partially discharged from the process and wherein particles with a size of x1 can also be partially discharged.

In addition, in a further embodiment of the invention, it can be provided that the comminution unit is in an operative connection with the first classification such that particles with a size greater than x1 which leave the comminution unit can be at least partially returned from the first classification to the comminution unit.

In a further alternative embodiment of the reactor arrangement according to the invention, it is provided that the reactor is operatively connected to a first sieve in such a way that the particles are classified in a sieve after being discharged from the reactor and that particles with a size of x1 can be at least partially fed to the reactor head, particles smaller than x1 can be discharged from the process and the first sieve is operatively connected to a comminution unit in such a way that particles larger than x1 can be comminuted in the comminution unit, characterized in that the comminution unit is operatively connected to the first sieve in such a way that particles from the comminution unit can be fed to the first sieve.

The various embodiments of the invention mentioned in this application can be advantageously combined with one another, unless stated otherwise in individual cases. The invention is explained below in exemplary embodiments with reference to the accompanying drawings. They show:

Figure 1 is a schematic representation of an embodiment of a reactor arrangement for the pyrolysis of hydrocarbon-containing fluids,

Figure 2 is a schematic representation of another embodiment of a reactor arrangement for the pyrolysis of hydrogen-containing fluids and

Figure 3 is a third schematic representation of a further embodiment of a reactor arrangement for the pyrolysis of hydrogen-containing fluids.

Figure 1 shows a schematic representation of a flow diagram of a process for methane pyrolysis. A reactor 1 is provided, wherein hydrocarbon-containing fluids are fed in counterflow to a moving bed of the reactor 1 consisting of particles. The particles of the moving bed and the hydrocarbon-containing fluids are heated to a defined temperature in the range between 800-1600 °C. Particles of the moving bed are introduced at a reactor head 2, wherein particles of the moving bed are discharged at a reactor sump 3. The reactor 1 is operatively connected to the reactor sump 3 with a first screening device 4 for classifying particles. The first screening device 4 serves to classify the particles in at least a first stage, so that particles with a desired particle size, or particles of a first fraction, can be returned to the reactor 1.

The screening device 4 thus forms a classifying device which is designed to classify particles taken from the reactor sump 3 and to separate a particle fraction with a uniform particle size x1, which has a grain band, for return to the reactor head 2. The uniform particle size x1 can preferably be in the range of 2 - 4 mm, particularly preferably in the range of 2.5 - 3.5 mm. The grain band preferably corresponds to a scatter of +/- 0.75 mm around the uniform particle size x1, wherein at least 90 wt.% and preferably at least 95 wt.% of the particles have a diameter within the grain band.

Figure 1 shows that the first screening device 4 is operatively connected to a crushing unit 5 for crushing at least a fraction of the classified particles. The crushing unit 5 can subsequently crush particles whose particle size is larger than a desired size, so that a narrow grain band can be achieved in the particle distribution.

The first screening device 4 comprises at least one sieve for classifying the particles. The first screening device 4 is connected to the reactor head 2 in such a way that particles with a size x1 can be fed from the first screening device 4 to the reactor 1. Particles of the desired size x1 can thus be fed directly back into the reactor 1. Various known conveying devices, not shown here, can be used for conveying. In addition to conveyor belts and bucket elevators, ventilation or gas-operated conveying devices are also conceivable. The first screening device 4 is also operatively connected to the comminution unit 5 in such a way that particles with a size greater than x1 can be fed from the first screening device 4 to the comminution device 5. Larger particles can thus be crushed and fed back to the screening device 4 so that particles of the desired size x1 can be continuously conveyed into the reactor 1 without particles having to be directly discharged from the process.

In addition, a second screening device 6 is provided. The second screening device 6 is connected to the reactor head 2 in such a way that particles with a fraction x1 can be fed from the second screening device 6 to the reactor 1. The second screening device 6 is also operatively connected to the comminution unit 5 so that particles with a fraction greater than x1 can be fed from the second screening device 6 to the comminution device 5.

The particle size is adjusted uniformly in the recirculation by sieving and grinding, i.e. in a narrow grain range related to the particle diameter. For this purpose, the particles are classified in the first screening device 4 after they are discharged from the reactor 1, and then particles with a specified size x1 are fed back into the reactor 1. To close the mass and particle balance, the comminution unit 5 is provided, which crushes the particles larger than x1. The material from the comminution unit 5 is classified in the second screening device 6, with large particles larger than x1 being partially fed back into the mill. Particles with a size of x1 are fed back into the reactor 1. The product fraction can be composed of particles with a size of less than x1 mm, x1 mm and larger than x1.

Figure 2 shows an alternative design of a reactor arrangement with a reactor (1). It is provided that the reactor (1) is operatively connected to a comminution unit (5), which in turn is operatively connected to a classification unit (6). The classified particles can be fed at least partially both to the comminution unit (5) and to the reactor (1).

An alternative embodiment is shown in Figure 3. The particulate material from the reactor sump is fed to a first screening device 4, whereby the particles larger than x1 can be fed to a crushing unit 5, which adjusts the particles to a size smaller than x1 and returns them to the first screening device 4 for classification by means of suitable conveying. The middle fraction x1 is at least partially fed to the reactor 1, and the smaller particles smaller than x1 are discharged from the process.

list of reference symbols

1 reactor

2 reactor head

3 reactor sump

4 First screening device 5 Crushing unit

6 Second screening device

Claims

patent claims 1. A method at least for the pyrolysis of hydrocarbon-containing fluids at least for the production of at least hydrogen-containing fluids, wherein the hydrocarbon-containing fluids are fed to a reactor shaft of a reactor (1) in counterflow to a moving bed of the reactor (1) consisting of particles, wherein at least the particles of the moving bed and the hydrocarbon-containing fluids are heated to a defined temperature in the range between 800-1600 °C, wherein particles of the moving bed are introduced at a reactor head (2) and wherein particles of the moving bed are discharged at a reactor sump (3), characterized in that the particles of the moving bed are conditioned after being discharged from the reactor sump (3), that the particles subjected to conditioning are at least partially introduced at the reactor head (2) and that the particles introduced at the reactor head (2) have a uniform particle size x1, wherein the uniform particle size has a grain band. 2. Method according to claim 1, characterized in that the conditioning comprises at least one classification. 3. Method according to claim 1 or 2, characterized in that the conditioning comprises at least one comminution of particles. 4. Method according to one of claims 1 to 3, characterized in that particles are classified in a first screening device and particles larger than x1 are crushed in a crushing unit (5), that the crushed particles are classified in a second conditioning unit (6), wherein after the second conditioning, particles with a size of x1 are at least partially fed to the reactor (1). 5. Method according to claim 4, characterized in that particles with a size greater than x1 which leave the comminution unit (5) are at least partially returned from the second conditioning (6) to the comminution unit (5). 6. Method according to one of claims 1 to 3, characterized in that the particles from the reactor sump (3) are fed to a comminution unit (5) and are crushed, the crushed particles being classified in a first sieving device (4) and particles with a size of x1 being at least partially fed to the reactor (1), characterized in that the particles smaller than x1, larger than x1 are at least partially and remaining particles of size x1 are discharged from the process. 7. Method according to claim 6, characterized in that particles with a size greater than x1 which leave the comminution unit (5) are at least partially returned from the screening device (4) into the comminution unit (5). 8. Method according to one of claims 1 to 3, characterized in that the particles are classified in a first screening device (4) after discharge and that particles with a size of x1 are at least partially fed to the reactor head (2), particles smaller than x1 are discharged from the process and particles larger than x1 are crushed in a crushing unit (5), characterized in that the particles from the crushing unit (5) are fed to the first screening device (4). 9. Process according to one of claims 1 to 8, characterized in that the uniform particle size x1 is in the range of 2 - 4 mm, preferably in the range of 2.5 - 3.5 mm. 10. Process according to one of claims 1 to 9, characterized in that the grain band corresponds to a scatter of +/- 0.75 mm around the uniform particle size x1, wherein at least 90% by weight and preferably at least 95% by weight of the particles have a diameter within the grain band. 11. Reactor arrangement at least for the pyrolysis of hydrocarbon-containing fluids at least for the production of at least hydrogen-containing fluids, with a reactor (1), wherein the reactor (1) has a reactor jacket and a reactor shaft arranged within the reactor jacket, wherein the reactor (1) has a reactor head (2) and a reactor sump (3), wherein the reactor head (2) and the reactor sump (3) each have at least temporarily closable feed openings and discharge openings through which at least fluids or solids, in particular particles, are to be introduced or discharged, so that in order to produce a moving bed through the reactor head (2) particles are at least temporarily continuously introduced into the reactor shaft, characterized in that the reactor (1) is in operative connection with the reactor sump (3) by means of a device for conditioning particles. 12. Reactor arrangement according to claim 11, characterized in that the device for conditioning particles comprises at least one classifying device (4, 6) which is designed to classify particles removed from the reactor sump (3) and to separate a particle fraction with a uniform particle size x1, which has a grain band, for return to the reactor head (2). 13. Reactor arrangement according to claim 12, characterized in that the uniform particle size x1 is in the range of 2 - 4 mm, preferably in the range of 2.5 - 3.5 mm. 14. Reactor arrangement according to claim 12 or 13, characterized in that the grain band has a scatter of +/- 0.75 mm around the uniform particle size x1, wherein at least 90 wt.% and preferably at least 95 % by weight of the particles have a diameter within the grain band. 15. Reactor arrangement according to one of claims 11 to 14, characterized in that the reactor (1) is operatively connected to the reactor sump (3) with a device for conditioning particles with at least one first sieving device. 16. Reactor arrangement according to one of claims 11 to 15, characterized in that the reactor (1) with the reactor sump (3) is in operative connection with a device for conditioning particles with at least one comminution unit (5) for comminuting at least some of the particles. 17. Reactor arrangement according to one of claims 11 to 16, characterized in that the conditioning has a first screening device (4) for classifying the particles, which is operatively connected to a comminution unit (5), which in turn is operatively connected to a second screening device (6), characterized in that the second screening device (6) is operatively connected to the reactor head (2). 18. Reactor arrangement according to claim 17, characterized in that the second screening device (6) is operatively connected to the comminution unit (5) in such a way that particles with a size greater than x1 can be fed from the second screening device (6) to the comminution device (5). 19. Reactor arrangement according to one of claims 11 to 16, characterized in that the reactor (1) with the reactor sump (3) is in an operative connection with a device for conditioning with a crushing unit (5), which is in an operative connection with a first sieving device (4), wherein the crushed particles can be classified in the first sieving device (4), wherein the first sieving device (4) is in an operative connection with the reactor head (2), and wherein particles with a size of x1 can be at least partially fed to the reactor (1), characterized in that a discharge of particles is possible at different points in the conditioning. 20. Reactor arrangement according to claim 19, wherein the first screening device (4) is operatively connected to the comminution unit (5) such that particles with a size greater than x1 which leave the comminution unit (5) can be at least partially returned to the comminution unit (5). 21. Reactor arrangement according to one of claims 11 to 16, characterized in that the reactor (1) is operatively connected to the reactor sump (3) with at least one first screening device (4) such that particles with a size of x1 can be fed to the reactor head (2), characterized in that the first screening device (4) enables particles to be discharged, characterized in that the first screening device (4) is operatively connected to a comminution unit (5) such that particles can be fed to the comminution unit (5), characterized in that the first screening device (4) is operatively connected to the comminution unit (5) such that particles from the comminution unit (5) can be fed to the first screening device (4).