US-20260124590-A1 - PLANT AND PROCESS FOR HIGH-EFFICIENCY PRODUCTION OF HYDROGEN BY PYROLYSIS

US20260124590A1US 20260124590 A1US20260124590 A1US 20260124590A1US-20260124590-A1

Abstract

The present invention relates to a plant for high-efficiency production of hydrogen by pyrolysis of an input gas mixture comprising gaseous hydrocarbons, said plant comprising: a reactor ( 1 ) for heating and pyrolyzing said input gas mixture by an electric arc and consequent production of an output produced mixture enriched with hydrogen and containing a solid fraction (Carbon Black and/or carbon in various shapes); and a heat exchanger ( 4 ) for pre-heating said input gas mixture and for cooling said output produced mixture. The invention also relates to a process for high-efficiency production of hydrogen by pyrolysis

Inventors

Paolo Argenta
Enrico Malfa
Mattia Bissoli
Ronald Victor Manuel Lopez-Gomez
Petrus Johannes JONKER

Assignees

TENOVA S.P.A.

Dates

Publication Date: 20260507
Application Date: 20250627
Priority Date: 20230112

Claims (17)

1 .- 16 . (canceled)
17 . A system for the production at high efficiency of hydrogen by pyrolysis of an input gas mixture comprising gaseous hydrocarbons, the system comprising: a reactor for heating and pyrolyzing the input gas mixture by an electric arc and consequent production of an output produced mixture in which the hydrogen concentration is greater than the hydrogen concentration in the input gas mixture, and containing a solid fraction comprising carbon; the reactor including: a containment structure defining a reaction chamber, provided with controllable openings for the input of the input gas mixture, for the output of the produced mixture; at least one electrode, disposed through one or more holes in the containment structure, and sealing elements between the holes and the at least one electrode for preventing gas exchange between interior and exterior of the containment structure, and at least one electrically conductive element placed at least partially within the reaction chamber, wherein the at least one electrode is movable, relative to other electrodes or to the electrically conductive element, along its axis, and wherein the electric arc is formed between the one or more electrodes and the at least one electrically conductive element; and a heat exchanger configured to pre-heat the input gas mixture and cool the output produced mixture, wherein the heat exchanger provides one or more heat exchange and storage elements, and the heat exchange and storage elements store heat by cooling the produced mixture exiting the reactor and successively or simultaneously transfer heat by pre-heating the gas mixture entering the reactor.
18 . The system according to claim 17 , wherein the input gas mixture comprises gases produced from renewable sources.
19 . The system according to claim 17 , wherein the at least one electrode is arranged with a substantially vertical axis.
20 . The system according to claim 17 , wherein the electrically conductive element is fixed relative to the containment structure.
21 . The system according to claim 17 , wherein the electrically conductive element is entirely within the reaction chamber.
22 . The system according to claim 17 , further comprising: a solid-gas separator configured to remove solid and powder components from the output produced mixture; and a gas-gas separator for dividing the output produced mixture, being free from solid components, in a mixture further enriched with hydrogen and a mixture mainly composed of other residual gases.
23 . The system according to claim 17 , wherein the heat exchange and storage elements include a plurality of elements of similar shape to each other, the heat exchanger comprising: a first chamber, including: at least one upper inlet, placed in the top of the first chamber and configured for introduction of the heat exchange and storage elements into the heat exchanger, at least one first-chamber inlet in fluid communication with the reactor and configured to receive the output produced mixture from the reactor such that heat of the output produced mixture is transferred to the heat exchange and storage elements, at least one first-chamber outlet configured to output the cooled output produced mixture at a temperature lower than the temperature of the output produced mixture received from the reactor at the at least one first-chamber inlet; and a second chamber of the heat exchanger, in fluid connection with the first chamber of the heat exchanger and disposed at a vertical height lower than the first chamber, the second chamber including: at least one upper inlet configured to receive the heat exchange and storage elements, being hot, from the first chamber, wherein the heat exchange and storage elements pass by gravity from the first chamber to the second chamber at least one second-chamber inlet configured to receive the input gas mixture to be processed, such that the heat exchange and storage elements in the second chamber transfer heat to the input gas mixture, at least one second-chamber outlet in fluid communication with and configured to output the heated input gas mixture to an inlet of the reactor, and at least one bottom outlet of the second chamber, configured for release of the heat exchange and storage elements from the heat exchanger.
24 . The system according to claim 23 , wherein the heat exchanger comprises a transition area between the first and the second chambers, the transition area having a passage section, for passage of the heat exchange and storage elements from the first chamber to the second chamber.
25 . The system according to claim 24 , wherein the transition area has a transverse dimension at least equal to about 10 times an average dimension of the heat exchange and storage elements, and a length in the direction of the motion of the heat exchange and storage elements at least equal to about 20 times the average dimension of the elements.
26 . The system according to claim 24 wherein the heat exchanger comprises a first seal disposed at the upper inlet of the first chamber and a second seal disposed at the bottom outlet of the second chamber, the first and second seals configured to selectively permit traversal of the heat exchange and storage elements into the first chamber and out of the second chamber and to prevent fluids, including gases, from entering and exiting the heat exchanger.
27 . The system according to claim 26 , wherein the heat exchanger comprises, downstream of the bottom outlet of the second chamber, a flow control mechanism configured to control and adjust flow of the exchange and storage elements from the bottom outlet.
28 . The system according to claim 27 , wherein the flow control mechanism adjusts the flow of the heat exchange and storage elements through the heat exchanger such that the first chamber, transition area and second chamber of the heat exchanger are always substantially filled with the heat exchange and storage elements such that the heat exchange and storage elements never free-flow uncontrolled within the heat exchanger.
29 . The system according to claim 28 , further comprising: a first container configured to hold the heat exchange and storage elements; a first sealing valve configured to open and close for respectively passing and blocking flow of the heat exchange and storage elements from an outlet of the first container and to block flow of gases therethrough; a second container configured to receive the heat exchange and storage elements from the first container via the first sealing valve, the second container having an environmental control system configured to control at least one of temperature, pressure, and constitution of the interior environment of the second container; a second sealing valve configured to open and close for respectively passing and blocking flow of the heat exchange and storage elements from an outlet of the second container and to block flow of gases therethrough; a third container configured to receive the heat exchange and storage elements from the second container via the second sealing valve, closed, and having an outlet of the third container directly connected to the at least one upper inlet of the first chamber of the heat exchanger.
30 . The system according to claim 28 , further comprising a first container configured and disposed to receive the flow of heat exchange and storage elements from the second chamber via the flow control mechanism; a first sealing valve configured to open and close for respectively passing and blocking flow of the heat exchange and storage elements from the first container and to block flow of gases therethrough; a second container, configured and disposed to receive a load of the heat exchange and storage elements from the first container, the second container having an environmental control system configured to control at least one of temperature, pressure, and constitution of the interior environment of the second container; a second sealing valve configured to open and close for respectively passing and blocking flow of the heat exchange and storage elements from the second container and to block flow of gases therethrough.
31 . The system according to claim 17 , wherein the heat exchange and storage elements comprise at least a first array and a second array, permeable to the passage of the gases entering or exiting the reactor, wherein in a first step, the output produced mixture exiting the reactor pass through the first array, heating the heat exchange and storage elements of the first array, and the input gas mixture passes through the second array, heating the input gas mixture, and in a second step the gas flows are inverted, such that the output produced mixture exiting the reactor passes through the second array, heating the heat exchange and storage elements of the second array, and the input gas mixture passes through the first array, heating the input gas mixture.
32 . A method for high-efficiency production of hydrogen by pyrolysis of a gas mixture comprising gaseous hydrocarbons, the process comprising: pre-heating the gas mixture, by causing the gas mixture to contact one or more previously heated heat storage elements, thereby cooling the one or more heat storage elements, further heating the gas mixture by an electric arc to effect pyrolysis of the gas mixture thereby increasing the hydrogen concentration to produce an output gas mixture; cooling the output gas mixture by causing the output gas mixture to contact the cooled one or more heat storage elements thereby producing the previously heated one or more heat storage elements.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present application is a Continuation of International Application No. PCT/IB20242/050284, entitled PLANT AND PROCESS FOR HIGH-FREQUENCY PRODUCTION OF HYDROGEN BY PYROLYSIS,” filed Jan. 11, 2024 (docket number 3101-001-04), which is pending at the time of this filing. International Application No. PCT/IB20242/050284 claims priority to Italian patent application number 102023000000258, entitled Impianto e procedimento per la produzione ad elevata efficienza di idrogeno mediante pirolisi, filed Jan. 12, 2023 (docket number 3101-001-IT), which is granted as Italian patent number 782024000166449. To the extent not inconsistent with the disclosure herein, the applications listed above are incorporated by reference in their entirety. SUMMARY The present invention refers to a plant for high efficiency production of hydrogen by pyrolysis. The invention further refers to a process for high efficiency production of hydrogen by pyrolysis. In more detail, the invention refers to the production of hydrogen by pyrolysis reactions of hydrocarbons. As known, the solutions for producing hydrogen known to the state of the art are divided in categories depending on the basic chemical reaction for obtaining the hydrogen molecule, in particular to which a color is assigned for “disclosing” purposes. In particular, mention can be made about: “grey” hydrogen, wherein the production occurs by steam reforming the methane, a technology which involves a significant impact from the point of view of CO2 emissions;“blue” hydrogen, wherein steam reforming the methane is operated with capture of CO2;“green” hydrogen, wherein the production occurs by electrolysis of water using electric energy produced from renewable sources;“turquoise” hydrogen, providing a direct pyrolysis of methane (and/or other hydrocarbons). This latter technology, compared to the others mentioned, requires a lower amount of energy, (up to 7 times less energy-consuming, for example, than the process for producing green hydrogen). In particular, the production of “turquoise” hydrogen developed recently, substantially with three technologies, and in particular that referred to below as technology A, based on using “bubbles in a molten bath”, technology B, based on using plasma (plasma based) and technology C, based on using a catalytic bed of pellets. The solution proposed according to the present invention was studied on the basis of technology B, a technology currently employed on an industrial scale at high/very high temperature for producing C2H2 (acetylene) and Carbon Black (CB) wherein hydrogen is a by-product. In particular, employing the B-type technology, based on plasma, commonly uses solutions such as plasma torches, wherein an electric arc is generated through metal electrodes (anode and cathode) normally supplied by direct current and usually cooled through circuits where water circulates. An alternative for technology B or “plasma technology” consists in using electrodes made of carbon, usually graphite, operating by both direct and alternate current. In both cases, in order to allow the electric power to be adjusted, cathode and anode are installed along axes inclined with respect to each other, such that, through their moving, moving the ends close and away, and accordingly varying the current, with the same voltage, is possible. In this technological context, a distinction can be made between: directheating solutions, wherein methane is generally injected through the torch or in proximity to the plasma arc;indirect heating solutions, wherein the reactor is made by creating two (or more) areas such as to segregate the electric arc. Therefore, the reactant gas is heated by a second carrier gas which transfers the energy from the arc to methane. This configuration is usually used to maximize the production of CB. The flow exiting the reactor (usually consisting of a mixture of H2, C2H2, and other gases in a lower amount) contains one or more classes of CB. Therefore, the flow is cooled and treated in gas/solid separation systems at high efficiency (scrubber, cyclone, filter). In the case of systems for producing CB, the gaseous current exiting the filtering system, rich in H2, is usually treated as an effluent, and made inert through a torch before being released in the atmosphere. However, the known technology B or plasma technology when applied has operative limits, and in particular: 1. obstruction of the torch in the case of injecting methane from the torch itself due to the formation of solid C in proximity to the tip. This defect mainly occurs when using plasma torches or solutions based on injecting the reactant gas through holed electrodes;2. loss of a part of the energy useful to the reaction in the cooling system (such as for example for the torches cooled by water);3. difficulty in moving and replacing the electrodes due to the inclination of the latter, in particular for the AC case;4. difficulty in