US 11,773,335 B2 · Heat source for pyrolysis process

Abstract

Systems and methods are provided for using a reverse flow reactor (or another reactor with flows in opposing directions at different parts of a process cycle) for pyrolysis of hydrocarbons. The systems and methods can include a reactor that includes a combustion catalyst to initiate and/or maintain combustion within the reactor in a controlled manner during the heating and/or regeneration portion(s) of the reaction cycle. A fuel can also be used that has a greater resistance to auto-combustion, such as a fuel that is composed primarily of methane and/or other hydrocarbons. During operation, the temperature in at least an initial portion of the reactor can be maintained at a temperature so that auto-ignition of the auto-combustion resistant fuel injected during the heating step(s) is reduced or minimized. This can allow combustion to be initiated when the auto-combustion resistant fuel comes into contact with the catalyst. Additionally, the amount and positioning of the catalyst within the reactor can be controlled so that combustion of the fuel takes place over a substantially longer period of time than combustion during a conventional reactor heating step. Because the fuel is moving within the reactor during combustion, extending the combustion time results in a substantial expansion of the volume where combustion occurs. Optionally in combination with an improved reaction cycle, this can expand the portion of the reactor that is directly heated by combustion, allowing for an improved temperature distribution within the reactor during the pyrolysis step.

Claims20

Dependent claims

A reverse flow reactor for performing cyclic reactions with flows entering the reactor from substantially opposing directions comprising:

a first zone comprising a primary end, a secondary end, and at least a portion of a reaction zone, the at least a portion of the reaction zone being proximate to the secondary end of the first zone, the reaction zone comprising a catalyst system;
a second zone comprising a first end and a second end, the second zone comprising a recuperation zone proximate to the first end,
wherein the first zone and the second zone are in fluid communication, the second end of the second zone being proximate to the secondary end of the first zone,
wherein the catalyst system comprises a first portion of combustion catalyst having a first combustion catalyst density and a second portion of combustion catalyst having a second combustion catalyst density,
wherein the second combustion catalyst density is greater than the first combustion catalyst density, and
wherein the first end of the second zone is closer to the first portion of combustion catalyst than the second portion of combustion catalyst.

3 more elements

A method for performing pyrolysis, comprising:

exposing a fuel stream comprising fuel and oxygen in a reactor to a catalyst system comprising a catalyst density gradient of combustion catalyst under combustion conditions to form a flue gas and to heat one or more surfaces in a reaction zone to a surface temperature of 750° C. or more, the one or more surfaces in the reaction zone comprising a peak temperature of 1000° C. or less, the fuel comprising 90 vol % or more CH4, the fuel stream flowing in the reactor in a first flow direction;
and
exposing a hydrocarbon-containing stream to the one or more surfaces in the reaction zone to pyrolyze at least a portion of the hydrocarbon-containing stream to form a pyrolyzed product, a flow direction of the hydrocarbon-containing stream comprising a second flow direction that is substantially opposite to the first flow direction,
wherein the reactor comprises a reverse flow reactor for performing cyclic reactions with flows entering the reactor from substantially opposing directions comprising:
a first zone comprising a primary end, a secondary end, and at least a portion of the reaction zone, the at least a portion of the reaction zone being proximate to the secondary end of the first zone, the reaction zone comprising the catalyst system;
a second zone comprising a first end and a second end, the second zone comprising a recuperation zone proximate to the first end,
wherein the first zone and the second zone are in fluid communication, the second end of the second zone being proximate to the secondary end of the first zone,
wherein the catalyst system comprises a first portion of combustion catalyst having a first combustion catalyst density and a second portion of combustion catalyst having a second combustion catalyst density,
wherein the second combustion catalyst density is greater than the first combustion catalyst density, and
wherein the first end of the second zone is closer to the first portion of combustion catalyst than the second portion of combustion catalyst.

7 more elements

Dependencies are inferred from the claim text.

Heat source for pyrolysis process

Life of this patent

Heat source for pyrolysis process

Life of this patent

Abstract

Claims20