US-20260124610-A1 - METHOD FOR OPERATING A REACTOR, WHICH COMPRISES A CATALYST MATERIAL, FOR CATALYTICALLY STORING OR RELEASING HYDROGEN GAS, AND SYSTEM COMPRISING SUCH A REACTOR

Abstract

A method for operating a reactor comprising a catalyst material having catalytically hydrogenating or catalytically dehydrogenating hydrogen carrier medium by contacting the catalyst material with the hydrogen carrier medium in the reactor, and flushing the catalyst material with a flushing medium into the reactor thereby removing catalyst-deactivating substances. The flushing medium comprises a hydrogen carrier medium.

Inventors

• Alexander Weiss
• Alexander Seidel
• Alexander Pflüger
• Caspar Paetz

Assignees

• HYDROGENIOUS LOHC TECHNOLOGIES GMBH

Dates

Publication Date

20260507

Application Date

20221005

Priority Date

20221013

Claims (20)

1. 1 . A method for operating a reactor comprising a catalyst material, the method comprising the method steps of: catalytically hydrogenating or catalytically dehydrogenating hydrogen carrier medium by contacting the catalyst material with the hydrogen carrier medium in the reactor, and flushing the catalyst material with a flushing medium in the reactor and thereby removing catalyst-deactivating substances, wherein the flushing medium comprises a hydrogen carrier medium, wherein the flushing comprises an increase in pressure, a decrease in temperature and/or an increase in the mass flow of the flushing medium.
2. 2 . A method according to claim 1 , wherein that flushing properties are established in a specifically variable manner in dependence upon material properties of the flushing medium.
3. 3 . A method according to claim 1 , wherein during flushing in the reactor, there is present a flushing temperature between 100° C. and 350° C. and/or a flushing pressure for dehydrogenation between 0.5 barg and 6.0 barg.
4. 4 . A method according to claim 1 , wherein the flushing is effected in a hydrogen atmosphere, wherein the proportion of hydrogen gas at total pressure is at least 10%.
5. 5 . A method according to claim 1 , wherein the flushing is performed in a manner controlled by means of a control/regulating unit.
6. 6 . A method according to claim 1 , wherein the flushing is performed in a routine manner.
7. 7 . A method according to claim 1 , wherein the flushing medium having the catalyst-deactivating substances is cleaned in a cleaning unit, wherein the cleaning unit is configured as an adsorption unit, as a distillation unit and/or as a cleaning unit having a separating membrane.
8. 8 . A method according to claim 1 , wherein in that the flushing is effected during a low-capacity phase of the reactor.
9. 9 . A method according to claim 1 , wherein the catalytic hydrogenation or the catalytic dehydrogenation is effected in a capacity range above the nominal load.
10. 10 . A method according to claim 1 , wherein oxidative regeneration and/or flushing with hydrogen gas and/or flushing with water vapor is effected after the flushing.
11. 11 . A system for catalytically storing or releasing hydrogen gas from a hydrogen carrier medium, the system comprising: a reactor for catalytically hydrogenating or for catalytically dehydrogenating the hydrogen carrier medium by contacting it with catalyst material, a flushing medium feed for feeding a flushing medium into the reactor, and a control/regulating unit for performing the flushing in a regulated manner according to a method comprising the steps of: catalytically hydrogenating or catalytically dehydrogenating hydrogen carrier medium by contacting the catalyst material with the hydrogen carrier medium in the reactor, wherein flushing the catalyst material with a flushing medium in the reactor and thereby removing catalyst-deactivating substances, wherein the flushing medium comprises a hydrogen carrier medium, wherein the flushing comprises an increase in pressure, a decrease in temperature and/or an increase in the mass flow of the flushing medium.
12. 12 . A system according to claim 11 , wherein a recirculating line for recirculating hydrogen carrier medium from the reactor as flushing medium into the reactor, wherein a storage container is connected to the recirculating line.
13. 13 . (canceled)
14. 14 . A system according to claim 11 , wherein at least one sensor unit for detecting a proportion of catalyst-deactivating substances in the flushing medium, wherein the sensor unit is configured as a photometer and/or as a fluorescence spectrometer and is arranged outside the reactor.
15. 15 . A system according to claim 11 , wherein a cleaning unit for cleaning the flushing medium having the catalyst-deactivating substances.
16. 16 . A method according to claim 1 , wherein that flushing properties are established in a specifically variable manner in dependence upon physiochemical properties of the flushing medium.
17. 17 . A method according to claim 3 , wherein during flushing in the reactor, there is present a flushing temperature between between 150° C. and 330° C., and/or a flushing pressure for dehydrogenation between 0.8 barg and 5.5 barg.
18. 18 . A method according to claim 4 , wherein the proportion of hydrogen gas at total pressure is at least 50%.
19. 19 . A method according to claim 4 , wherein the proportion of hydrogen gas at total pressure is at least 90%.
20. 20 . A method according to claim 5 , wherein the flushing is performed in a manner controlled by means of a control/regulating unit, in dependence upon the catalyst activity and/or in dependence upon the hydrogen consumption at a hydrogen consumer.

Description

CROSS REFERENCE TO RELATED APPLICATIONS This application is a United States National Phase Application of International Application PCT/EP 2023/077573, filed Oct. 5, 2023, and claims the benefit of priority under 35 U.S.C. § 119 of German Application 10 2022 210 824.8, filed Oct. 13, 2022, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD The invention relates to a method for operating a reactor, comprising a catalyst material, for catalytically storing or releasing hydrogen gas as well as to a system comprising such a reactor. BACKGROUND DE 10 2015 219 305 A1 discloses a device for catalytically releasing hydrogen gas from a hydrogen carrier medium. The release reaction is a dehydrogenation reaction of the hydrogen carrier medium. The dehydrogenation is effected in a dehydrogenation reactor by means of a catalyst. Tests have shown that the activity of the catalyst decreases the more it is used. As a consequence of the loss of activity, the reactor power decreases. The volumetric and gravimetric power density during the hydrogen release are reduced. The technical performance of the reactor is decreased. If a decreasing activity is established for the catalyst material, complex regeneration measures are required which can lead in particular to a temporary shutdown of the reactor. For regeneration purposes, an oxidative method can be used in order to regenerate the catalyst material. Increased safety measures are required owing to the use of oxygen. There is also a risk that oxygen-containing impurities are formed as a result of the oxidative regeneration, said impurities then having to be subsequently purified from the hydrogen carrier medium in a complex manner. The oxidative regeneration is complex and adversely affects the overall efficiency of the method. It has been found that the deactivation of the catalyst material can be caused by deposits which can be degradation products of the hydrogen carrier medium. The formation of degradation products depends on the process control during the hydrogenation or dehydrogenation of the hydrogen carrier medium. An adaptation of the hydrogenation or dehydrogenation method such that the formation of degradation products is reduced or can be avoided is very complex. SUMMARY It is an object of the invention to increase the service life of the catalyst material using simple methods. This object is achieved in accordance with the invention by a method having the features set forth in the description. The core of the invention is that catalyst-deactivating substances can be effectively flushed off from a catalyst material by means of a flushing medium. During flushing, the catalyst material can remain in a reactor which is used for catalytic hydrogenation or dehydrogenation of hydrogen carrier medium. Flushing is performed in a straightforward manner. In particular, the flushing medium is liquid. This improves flushing around the catalyst material and the removal of the catalyst-deactivating substances. A catalyst-deactivating substance is in particular a coking and/or a coke precursor which are formed in particular during the catalytic hydrogenation or catalytic dehydrogenation of the hydrogen carrier medium in the reactor. The catalyst-deactivating substances are in particular deposits, in particular aromatic and/or unsaturated molecules which are particularly large. In particular, large molecules according to this definition are planar, aromatic, Pi-conjugated hydrocarbon compounds with at least 16 carbon atoms and in particular at least 20 carbon atoms in the carbon skeleton. The catalyst-deactivating substances can be additionally or alternatively, in particular in dependence upon the degree of coking, completely graphitic carbon deposits on the catalyst material. The catalyst-deactivating substances are deposited in particular on a surface of the catalyst material and/or on the catalytically active precious metal, so that the hydrogenation reaction and/or dehydrogenation reaction is inhibited. It has been found that the method is suitable in a particularly advantageous manner for a hydrogen carrier medium. Hydrogen can be reversibly chemically bound to the hydrogen carrier medium and then released. In particular, such a hydrogen carrier medium is a liquid organic hydrogen carrier medium (LOHC). A hydrogen carrier medium which is present in a form, which is at least partially loaded with hydrogen, as perhydro-dibenzyltoluene (H18DBT), perhydro-benzyltoluene (H12BT), dicyclohexane and/or methylcyclohexane (C7H14), which can be dehydrogenated to form toluene (C7H8), has proven to be particularly suitable. It is also possible to use a mixture of hydrogen carrier medium in the form of perhydro-diphenylmethane and perhydro-biphenyl which are at least partially loaded with hydrogen. These compounds can be dehydrogenated to form diphenylmethane and biphenyl. A mixture of biphenyl to diphenylmethane in a ratio of 30:70, in particular 35:65 a