Process and catalyst structure employing intergal heat exchange with optional downstream flameholder

Claim 2

A reaction system for combustion of a combustible mixture of fuel and an oxygen-containing gas wherein a flowing stream of the combustible mixture, in vapor or gaseous form, is initially subject to partial combustion in the presence of a catalyst followed by complete combustion under non-catalytic conditions in a homogeneous combustion zone downstream from the catalyst comprising a housing containing: (a) a catalyst structure made up of a heat resistant support material composed of a plurality of common walls which form a multitude of adjacently disposed longitudinal channels for passage of the combustible mixture, wherein at least a part of the interior surface of at least a portion of the channels is coated with a catalyst for the combustible mixture and the interior surface of the remaining channels is not coated with catalyst such that the interior surface of the catalyst-coated channels are in heat exchange relationship with the interior surface of adjacent catalyst-free channels and wherein the catalyst-coated channels have a configuration which forms a more tortuous flow passage for the reaction mixture than the flow passage formed by the catalyst-free channels, such that only a portion of the combustible mixture undergoes combustion to afford a partially-combusted, gaseous mixture flowing at elevated temperature from an outlet end of the catalyst structure; (b) a homogeneous combustion zone comprising an enclosed space in fluid communication with the catalyst structure and located immediately downstream from the outlet end of the catalyst structure; and (c) a means for inducing recirculation into the partially-combusted mixture flowing through the homogeneous combustion zone whereby homogeneous combustion of the partially-combusted mixture is stabilized within the region of recirculation and complete combustion of the partially-combusted mixture is promoted within the homogeneous combustion zone.

Claim 3

The reaction system of claim 1, wherein the means for inducing recirculation into the partially-combusted mixture flow is a flameholder positioned downstream from the outlet end of the catalyst structure.

Claim 4

The reaction system of claim 2, wherein the flameholder is selected from a bluff body, a V-gutter, a cone, a perforated plate or a swirler.

Claim 5

The reaction system of claim 3, wherein the flameholder is positioned from about 0.2 to about 20 cm downstream from the outlet end of the catalyst structure.

Claim 6

The reaction system of claim 4, wherein the flameholder provides a geometric flow blockage in the homogeneous combustion zone of from about 10 to about 70 percent.

Claim 7

The reaction system of claims 1, 2 or 5, wherein the catalyst structure is constructed such that between about 20 to about 70 percent of the fuel in the combustible mixture is combusted in the catalyst structure.

Claim 8

The reaction system of claim 6, wherein the catalyst structure is constructed such that the temperature of the partially-combusted, gaseous mixture flowing out of the outlet end of the catalyst structure is between about 700° and 1000° C.

Claim 9

The reaction system of claim 1, wherein the catalyst-coated channels of the catalyst structure art periodically altered through a change in cross-sectional area, a change in direction along the longitudinal axis of the channels or a combination of both changes in cross-sectional area and direction along their longitudinal axis such that the flow direction of at least a portion of the gaseous reaction mixture in the catalyst-coated channels is changed at least a plurality of points as the gaseous reaction mixture passes through the catalyst-coated channels while the catalyst-free channels are substantially straight and of unaltered cross-sectional area along their longitudinal axis, such that the flow direction of gaseous reaction mixture through the catalyst-free channels is substantially unaltered.

Claim 10

The reaction system of claim 8, wherein the catalyst-coated channels are varied in cross-sectional area through a repeated inward and outward bending of the channel walls along the longitudinal axis of the channels or through the use of an obstruction means placed at a plurality of points along the longitudinal axis of the channels to partially obstruct the gaseous reaction mixture flow direction.

Claim 11

The reaction system of claim 9, wherein the catalyst-coated channels are varied in the cross-sectional area by the repeated inward and outward bending of the walls of the catalyst-coated channels which are corrugated in a herringbone pattern using corrugated sheets stacked in a non-nesting fashion.

Claim 12

The reaction system of claim 10, wherein the catalyst-coated channels and the catalyst-free channels are formed by a repeating three layer structure comprised of a first layer of corrugated sheet with longitudinal peaks separated by flat regions stacked upon a second layer composed of corrugated sheet in which the corrugations are formed as adjacent longitudinal ridges and valleys with these ridges and valleys forming a herringbone pattern along the length of the sheet making the second layer with the second layer being stacked in non-nesting fashion upon a third layer composed of corrugated metallic sheet in which the corrugations are formed as adjacent longitudinal ridges and valleys with the ridges and valleys forming a herringbone pattern along the length of the sheet making the third layer, and with catalyst for the reaction mixture being coated on the bottom side of the first layer and top side of the third layer such that catalyst-free channels are formed when the first layer of the repeating structure is set under the third layer of the next adjacent repeating three layer structure in a stacked pattern and catalyst-coated channels are formed between the bottom of the first layer and the top of the second layer and between the bottom of the second layer and the top of the third layer of the repeating three layer structure.

Claim 13

A reaction system for combustion of a combustible mixture of fuel and an oxygen-containing gas wherein a flowing stream of the combustible mixture, in vapor or gaseous form, is initially subject to partial combustion in the presence of a catalyst followed by complete combustion under non-catalytic conditions in a homogeneous combustion zone downstream from the catalyst comprising a housing containing: (a) a catalyst structure made up of a heat resistant support material composed of a plurality of common walls which form a multitude of adjacently disposed longitudinal channels for passage of the combustible mixture, wherein at least a part of the interior surface of at least a portion of the channels is coated with a catalyst for the combustible mixture and the interior surface of the remaining channels is not coated with catalyst such that the interior surface of the catalyst-coated channels are in heat exchange relationship with the interior surface of adjacent catalyst-free channels and wherein: (i) the catalyst-coated channels have a smaller average hydraulic diameter (D h ) than the catalyst-free channels; (ii) the catalyst-coated channels have a higher film heat transfer coefficient (h) than the catalyst-free channels; and (iii) the catalyst-coated channels form a more tortuous flow passage for the reaction mixture than the flow passage formed by the catalyst-free channels; such that only a portion of the combustible mixture undergoes combustion to afford a partially-combusted, gaseous mixture flowing at elevated temperature from an outlet end of the catalyst structure; (b) a homogeneous combustion zone comprising an enclosed space in fluid communication with the catalyst structure and located immediately downstream from the outlet end of the catalyst structure; and (c) a means for inducing recirculation in the partially-combusted mixture flowing through the homogeneous combustion zone whereby homogeneous combustion of the partially-combusted mixture is stabilized within the region of recirculation and complete combustion of the partially-combusted mixture is promoted within the homogeneous combustion zone.

Claim 14

A reaction system for combustion of a combustible mixture of fuel and an oxygen-containing gas wherein a flowing stream of the combustible mixture, in vapor or gaseous form, is initially subject to partial combustion in the presence of a catalyst followed by complete combustion under non-catalytic conditions in a homogeneous combustion zone downstream from the catalyst comprising a housing containing: (a) a catalyst structure made up of a heat resistant support material composed of a plurality of common walls which form a multitude of adjacently disposed longitudinal channels for passage of the combustible mixture, wherein at least a part of the interior surface of at least a portion of the channels is coated with a catalyst for the combustible mixture and the interior surface of the remaining channels is not coated with catalyst such that the interior surface of the catalyst-coated channels are in heat exchange relationship with the interior surface of adjacent catalyst-free channels and wherein: (i) the catalyst-coated channels have a smaller average hydraulic diameter (D h ) than the catalyst-free channels; (ii) the catalyst-coated channels have a higher film heat transfer coefficient (h) than the catalyst-free channels; and (iii) the catalyst-coated channels form a more tortuous flow passage for the reaction mixture than the flow passage formed by the catalyst-free channels; such that only a portion of the combustible mixture undergoes combustion to afford a partially-combusted, gaseous mixture flowing at elevated temperature from an outlet end of the catalyst structure; (b) a homogeneous combustion zone comprising an enclosed space in fluid communication with the catalyst structure and located immediately downstream from the outlet end of the catalyst structure; and (c) a means for inducing recirculation in the partially-combusted mixture flowing through the homogeneous combustion zone whereby homogeneous combustion of the partially-combusted mixture is stabilized within the region of recirculation and complete combustion of the partially-combusted mixture is promoted within the homogeneous combustion zone.

Claim 15

A reaction system for combustion of a combustible mixture of fuel and an oxygen-containing gas wherein a flowing stream of the combustible mixture, in vapor or gaseous form, is initially subject to partial combustion in the presence of a catalyst followed by complete combustion under non-catalytic conditions in a homogeneous combustion zone downstream from the catalyst comprising a housing containing: (a) a catalyst structure made up of a heat resistant support material composed of a plurality of common walls which form a multitude of adjacently disposed longitudinal channels for passage of the combustible mixture, wherein at least a part of the interior surface of at least a portion of the channels is coated with a catalyst for the combustible mixture and the interior surface of the remaining channels is not coated with catalyst such that the interior surface of the catalyst-coated channels are in heat exchange relationship with the interior surface of adjacent catalyst-free channels and wherein catalyst-coated channels form a more tortuous flow passage than the catalyst-free channels and have a film heat transfer coefficient (h) which is more than 1.5 times greater than the h for catalyst-free channels and the catalyst-coated channels represent from about 20% to about 80% of the total open frontal area in the catalyst structure, such that only a portion of the combustible mixture undergoes combustion to afford a partially-combusted, gaseous mixture flowing at elevated temperature from an outlet end of the catalyst structure; (b) a homogeneous combustion zone comprising an enclosed space in fluid communication with the catalyst structure and located immediately downstream from the outlet end of the catalyst structure; and (c) a means for inducing recirculation into the partially-combusted mixture flowing through the homogeneous combustion zone whereby homogeneous combustion of the partially-combusted mixture is stabilized within the region of recirculation and complete combustion of the partially-combusted mixture is promoted with the homogeneous combustion zone.

Claim 16

A reaction system for combustion of a combustible mixture of fuel and an oxygen-containing gas wherein a flowing stream of the combustible mixture, in vapor or gaseous form, is initially subject to partial combustion in the presence of a catalyst followed by complete combustion under non-catalytic conditions in a homogeneous combustion zone downstream from the catalyst comprising a housing containing: (a) a catalyst structure made up of a heat resistant support material composed of a plurality of common walls which form a multitude of adjacently disposed longitudinal channels for passage of the combustible mixture, wherein at least a part of the interior surface of at least a portion of the channels is coated with a catalyst for the combustible mixture and the interior surface of the remaining channels is not coated with catalyst such that the interior surface of the catalyst-coated channels are in heat exchange relationship with the interior surface of adjacent catalyst-free channels and wherein catalyst-coated channels form a more tortuous flow passage than the catalyst-free channels and have a film heat transfer coefficient (h) which is more than 1.5 times greater than the h for catalyst-free channels and the catalyst-coated channels represent from about 20% to about 80% of the total open frontal area in the catalyst structure, such that only a portion of the combustible mixture undergoes combustion to afford a partially-combusted, gaseous mixture flowing at elevated temperature from an outlet end of the catalyst structure; (b) a homogeneous combustion zone comprising an enclosed space in fluid communication with the catalyst structure and located immediately downstream from the outlet end of the catalyst structure; and (c) a means for inducing recirculation into the partially-combusted mixture flowing through the homogeneous combustion zone whereby homogeneous combustion of the partially-combusted mixture is stabilized within the region of recirculation and complete combustion of the partially-combusted mixture is promoted with the homogeneous combustion zone.

Claim 17

A reaction system for combustion of a combustible mixture of fuel and an oxygen-containing gas wherein a flowing stream of the combustible mixture, in vapor or gaseous form, is initially subject to partial combustion in the presence of a catalyst followed by complete combustion under non-catalytic conditions in a homogeneous combustion zone downstream from the catalyst comprising a housing containing: (a) a catalyst structure made up of a heat resistant support material composed of a plurality of common walls which form a multitude of adjacently disposed longitudinal channels for passage of the combustible mixture, wherein at least a part of the interior surface of at least a portion of the channels is coated with a catalyst for the combustible mixture and the interior surface of the remaining channels is not coated with catalyst such that the interior surface of the catalyst-coated channels are in heat exchange relationship with the interior surface of adjacent catalyst-fee channels and wherein catalyst-coated channels have a lower average hydraulic diameter (D h ) than the catalyst-free channels and the numeric ratio of average D h for the catalyst-coated channels divided by the average D h for the catalyst-free channels is smaller than the numeric ratio of open frontal area of the catalyst-coated channels divided by the open frontal area of the catalyst-free channels, such that only a portion of the combustible mixture undergoes combustion to afford a partially-combusted, gaseous mixture flowing at elevated temperature from an outlet end of the catalyst structure; (b) a homogeneous combustion zone comprising an enclosed space in fluid communication with the catalyst structure and located immediately downstream from the outlet end of the catalyst structure; and (c) a means for inducing recirculation into the partially-combusted mixture flowing through the homogeneous combustion zone whereby complete combustion of the partially-combusted mixture is stabilized within the region of recirculation and complete combustion of the partially-combusted mixture is promoted with the homogeneous combustion zone.

Claim 18

A reaction system for combustion of a combustible mixture of fuel and an oxygen-containing gas wherein a flowing stream of the combustible mixture, in vapor or gaseous form, is initially subject to partial combustion in the presence of a catalyst followed by complete combustion under non-catalytic conditions in a homogeneous combustion zone downstream from the catalyst comprising a housing containing: (a) a catalyst structure made up of a heat resistant support material composed of a plurality of common walls which form a multitude of adjacently disposed longitudinal channels for passage of the combustible mixture, wherein at least a part of the interior surface of at least a portion of the channels is coated with a catalyst for the combustible mixture and the interior surface of the remaining channels is not coated with catalyst such that the interior surface of the catalyst-coated channels are in heat exchange relationship with the interior surface of adjacent catalyst-fee channels and wherein catalyst-coated channels have a lower average hydraulic diameter (D h ) than the catalyst-free channels and the numeric ratio of average D h for the catalyst-coated channels divided by the average D h for the catalyst-free channels is smaller than the numeric ratio of open frontal area of the catalyst-coated channels divided by the open frontal area of the catalyst-free channels, such that only a portion of the combustible mixture undergoes combustion to afford a partially-combusted, gaseous mixture flowing at elevated temperature from an outlet end of the catalyst structure; (b) a homogeneous combustion zone comprising an enclosed space in fluid communication with the catalyst structure and located immediately downstream from the outlet end of the catalyst structure; and (c) a means for inducing recirculation into the partially-combusted mixture flowing through the homogeneous combustion zone whereby complete combustion of the partially-combusted mixture is stabilized within the region of recirculation and complete combustion of the partially-combusted mixture is promoted with the homogeneous combustion zone.

Claim 19

A reaction system for combustion of a combustible mixture of fuel and an oxygen-containing gas wherein a flowing stream of the combustible mixture, in vapor or gaseous form, is initially subject to partial combustion in the presence of a catalyst followed by complete combustion under non-catalytic conditions in a homogeneous combustion zone downstream from the catalyst comprising a housing containing: (a) a catalyst structure made up of a heat resistant support material composed of a plurality of common walls which form a multitude of adjacently disposed longitudinal channels for passage of the combustible mixture, wherein at least a part of the interior surface of at least portion of the channels is coated with a catalyst for the combustible mixture and the interior surface of the remaining channels is not coated with catalyst such that the interior surface of the catalyst-coated channels are in heat exchange relationship with the interior surface of adjacent catalyst-free channels and wherein: (i) the catalyst-coated channels have a higher film heat transfer coefficient (h) than the catalyst-free channels; (ii) the catalyst-coated channels have a smaller average hydraulic diameter (D h ) than the catalyst-free channels; and (iii) the numeric ratio of the average D h for the catalyst-coated channels divided by the average D h for the catalyst-free channels is smaller than the numeric ratio of the open frontal area of the catalyst-coated channels divided by the open frontal area of the catalyst-free channels; such that only a portion of the combustible mixture undergoes combustion to afford a partially-combusted, gaseous mixture flowing at elevated temperature from an outlet end of the catalyst structure; (b) a homogeneous combustion zone comprising an enclosed space in fluid communication with the catalyst structure and located immediately downstream from the outlet end of the catalyst structure; and (c) a means for inducing recirculation into the partially-combusted mixture flowing through the homogeneous combustion zone whereby homogeneous combustion of the partially-combusted mixture is stabilized within the region of recirculation and complete combustion of the partially-combusted mixture is promoted with the homogeneous combustion zone.

Claim 20

A reaction system for combustion of a combustible mixture of fuel and an oxygen-containing gas wherein a flowing stream of the combustible mixture, in vapor or gaseous form, is initially subject to partial combustion in the presence of a catalyst followed by complete combustion under non-catalytic conditions in a homogeneous combustion zone downstream from the catalyst comprising a housing containing: (a) a catalyst structure made up of a heat resistant support material composed of a plurality of common walls which form a multitude of adjacently disposed longitudinal channels for passage of the combustible mixture, wherein at least a part of the interior surface of at least portion of the channels is coated with a catalyst for the combustible mixture and the interior surface of the remaining channels is not coated with catalyst such that the interior surface of the catalyst-coated channels are in heat exchange relationship with the interior surface of adjacent catalyst-free channels and wherein: (i) the catalyst-coated channels have a higher film heat transfer coefficient (h) than the catalyst-free channels; (ii) the catalyst-coated channels have a smaller average hydraulic diameter (D h ) than the catalyst-free channels; and (iii) the numeric ratio of the average D h for the catalyst-coated channels divided by the average D h for the catalyst-free channels is smaller than the numeric ratio of the open frontal area of the catalyst-coated channels divided by the open frontal area of the catalyst-free channels; such that only a portion of the combustible mixture undergoes combustion to afford a partially-combusted, gaseous mixture flowing at elevated temperature from an outlet end of the catalyst structure; (b) a homogeneous combustion zone comprising an enclosed space in fluid communication with the catalyst structure and located immediately downstream from the outlet end of the catalyst structure; and (c) a means for inducing recirculation into the partially-combusted mixture flowing through the homogeneous combustion zone whereby homogeneous combustion of the partially-combusted mixture is stabilized within the region of recirculation and complete combustion of the partially-combusted mixture is promoted with the homogeneous combustion zone.

Claim 21

A reaction system for combustion of a combustible mixture of fuel and an oxygen-containing gas wherein a flowing stream of the combustible mixture, in vapor or gaseous form, is initially subject to partial combustion in the presence of a catalyst followed by complete combustion under non-catalytic conditions in a homogeneous combustion zone downstream from the catalyst comprising a housing containing: (a) a catalyst structure made up of a heat resistant support material composed of a plurality of common walls which form a multitude of adjacently disposed longitudinal channels for passage of the combustible mixture, wherein at least a part of the interior surface of at least a portion of the channels is coated with a catalyst for the combustible mixture and the interior surface of the remaining channels is not coated with catalyst such that the interior surface of the catalyst-coated channels are in heat exchange relationship with the interior surface of adjacent catalyst-free channels and wherein: (i) the catalyst-coated channels have a higher film heat transfer coefficient (h) than the catalyst-free channels; (ii) more than 50% of the total reaction mixture flow is through the catalyst-coated channels; and (iii) the catalyst-coated channels form a more tortuous flow passage for the combustible mixture than the flow passage formed by the catalyst-free channels; such that only a portion of the combustible mixture undergoes combustion to afford a partially-combusted, gaseous mixture flowing at elevated temperature from an outlet end of the catalyst structure; (b) a homogeneous combustion zone comprising an enclosed space in fluid communication with the catalyst structure and located immediately downstream from the outlet end of the catalyst structure; and (c) a means for inducing recirculation into the partially-combusted mixture flowing through the homogeneous combustion zone whereby homogeneous combustion of the partially-combusted mixture is stabilized within the region of recirculation and complete combustion of the partially-combusted mixture is promoted with the homogeneous combustion zone.

Claim 22

A reaction system for combustion of a combustible mixture of fuel and an oxygen-containing gas wherein a flowing stream of the combustible mixture, in vapor or gaseous form, is initially subject to partial combustion in the presence of a catalyst followed by complete combustion under non-catalytic conditions in a homogeneous combustion zone downstream from the catalyst comprising a housing containing: (a) a catalyst structure made up of a heat resistant support material composed of a plurality of common walls which form a multitude of adjacently disposed longitudinal channels for passage of the combustible mixture, wherein at least a part of the interior surface of at least a portion of the channels is coated with a catalyst for the combustible mixture and the interior surface of the remaining channels is not coated with catalyst such that the interior surface of the catalyst-coated channels are in heat exchange relationship with the interior surface of adjacent catalyst-free channels and wherein: (i) the catalyst-coated channels have a higher film heat transfer coefficient (h) than the catalyst-free channels; (ii) more than 50% of the total reaction mixture flow is through the catalyst-coated channels; and (iii) the catalyst-coated channels form a more tortuous flow passage for the combustible mixture than the flow passage formed by the catalyst-free channels; such that only a portion of the combustible mixture undergoes combustion to afford a partially-combusted, gaseous mixture flowing at elevated temperature from an outlet end of the catalyst structure; (b) a homogeneous combustion zone comprising an enclosed space in fluid communication with the catalyst structure and located immediately downstream from the outlet end of the catalyst structure; and (c) a means for inducing recirculation into the partially-combusted mixture flowing through the homogeneous combustion zone whereby homogeneous combustion of the partially-combusted mixture is stabilized within the region of recirculation and complete combustion of the partially-combusted mixture is promoted with the homogeneous combustion zone.

Claim 23

A reaction system for combustion of a combustible mixture of fuel and an oxygen-containing gas wherein a flowing stream of the combustible mixture, in vapor or gaseous form, is initially subject to partial combustion in the presence of a catalyst followed by complete combustion under non-catalytic conditions in a homogeneous combustion zone downstream from the catalyst comprising a housing containing: (a) a catalyst structure made up of a heat resistant support material composed of a plurality of common walls which form a multitude of adjacently disposed longitudinal channels for passage of the combustible mixture, wherein at least a part of the interior surface of at least a portion of the channels is coated with a catalyst for the combustible mixture and the interior surface of the remaining channels is not coated with catalyst such that the interior surface of the catalyst-coated channels are in heat exchange relationship with the interior surface of adjacent catalyst-free channels and wherein: (i) the catalyst-coated channels have a higher film heat transfer coefficient (h) than the catalyst-free channels by a factor of greater than 1.2; and (ii) more than 40%, but less than 50% of the total reaction mixture flow is through the catalyst-coated channels; and (iii) the catalyst-coated channels form a more tortuous flow passage for the combustible mixture than the flow passage formed by the catalyst-free channels; such that only a portion of the combustible mixture undergoes combustion to afford a partially-combusted, gaseous mixture flowing at elevated temperature from an outlet end of the catalyst structure; (b) a homogeneous combustion zone comprising an enclosed space in fluid communication with the catalyst structure and located immediately downstream from the outlet end of the catalyst structure; and (c) a means for inducing recirculation into the partially-combusted mixture flowing through the homogeneous combustion zone whereby homogeneous combustion of the partially-combusted mixture is stabilized within the region of recirculation and complete combustion of the partially-combusted mixture is promoted with the homogeneous combustion zone.

Claim 24

A reaction system for combustion of a combustible mixture of fuel and an oxygen-containing gas wherein a flowing stream of the combustible mixture, in vapor or gaseous form, is initially subject to partial combustion in the presence of a catalyst followed by complete combustion under non-catalytic conditions in a homogeneous combustion zone downstream from the catalyst comprising a housing containing: (a) a catalyst structure made up of a heat resistant support material composed of a plurality of common walls which form a multitude of adjacently disposed longitudinal channels for passage of the combustible mixture, wherein at least a part of the interior surface of at least a portion of the channels is coated with a catalyst for the combustible mixture and the interior surface of the remaining channels is not coated with catalyst such that the interior surface of the catalyst-coated channels are in heat exchange relationship with the interior surface of adjacent catalyst-free channels and wherein: (i) the catalyst-coated channels have a higher film heat transfer coefficient (h) than the catalyst-free channels by a factor of greater than 1.2; and (ii) more than 40%, but less than 50% of the total reaction mixture flow is through the catalyst-coated channels; and (iii) the catalyst-coated channels form a more tortuous flow passage for the combustible mixture than the flow passage formed by the catalyst-free channels; such that only a portion of the combustible mixture undergoes combustion to afford a partially-combusted, gaseous mixture flowing at elevated temperature from an outlet end of the catalyst structure; (b) a homogeneous combustion zone comprising an enclosed space in fluid communication with the catalyst structure and located immediately downstream from the outlet end of the catalyst structure; and (c) a means for inducing recirculation into the partially-combusted mixture flowing through the homogeneous combustion zone whereby homogeneous combustion of the partially-combusted mixture is stabilized within the region of recirculation and complete combustion of the partially-combusted mixture is promoted with the homogeneous combustion zone.

Claim 25

A reaction system for combustion of a combustible mixture of fuel and an oxygen-containing gas wherein a flowing stream of the combustible mixture, in vapor or gaseous form, is initially subject to partial combustion in the presence of a catalyst followed by complete combustion under non-catalytic conditions in a homogeneous combustion zone downstream from the catalyst comprising: (a) a catalyst structure made up of a heat resistant support material composed of a plurality of common walls which form a multitude of adjacently disposed longitudinal channels for passage of the combustible mixture, wherein at least a part of the interior surface of at least a portion of the channels is coated with a catalyst for the combustible mixture and the interior surface of the remainin channels is not coated with catalyst such that the interior surface of the catalyst-coated channels are in heat exchange relationship with the interior surface of adjacent catalyst-free channels and wherein: (i) the catalyst-coated channels have a higher film heat transfer coefficient (h) than the catalyst-free channels by a factor of greater than 1.3; and (ii) more than 30%, but less than 40% of the total reaction mixture flow is through the catalyst-coated channels; and (iii) the catalyst-coated channels form a more tortuous flow passage for the combustible mixture than the flow passage formed by the catalyst-free channels; such that only a portion of the combustible mixture undergoes combustion to afford a partially-combusted, gaseous mixture flowing at elevated temperature from the outlet end of the catalyst structure; (b) a homogeneous combustion zone comprising an enclosed space in fluid communication with the catalyst structure and located immediately downstream from the outlet end of the catalyst structure; and (c) a means for inducing recirculation into the partially-combusted mixture flowing through the homogeneous combustion zone whereby homogeneous combustion of the partially-combusted mixture is stabilized within the region of recirculation and complete combustion of the partially-combusted mixture is promoted with the homogeneous combustion zone.

Claim 26

A reaction system for combustion of a combustible mixture of fuel and an oxygen-containing gas wherein a flowing stream of the combustible mixture, in vapor or gaseous form, is initially subject to partial combustion in the presence of a catalyst followed by complete combustion under non-catalytic conditions in a homogeneous combustion zone downstream from the catalyst comprising: (a) a catalyst structure made up of a heat resistant support material composed of a plurality of common walls which form a multitude of adjacently disposed longitudinal channels for passage of the combustible mixture, wherein at least a part of the interior surface of at least a portion of the channels is coated with a catalyst for the combustible mixture and the interior surface of the remainin channels is not coated with catalyst such that the interior surface of the catalyst-coated channels are in heat exchange relationship with the interior surface of adjacent catalyst-free channels and wherein: (i) the catalyst-coated channels have a higher film heat transfer coefficient (h) than the catalyst-free channels by a factor of greater than 1.3; and (ii) more than 30%, but less than 40% of the total reaction mixture flow is through the catalyst-coated channels; and (iii) the catalyst-coated channels form a more tortuous flow passage for the combustible mixture than the flow passage formed by the catalyst-free channels; such that only a portion of the combustible mixture undergoes combustion to afford a partially-combusted, gaseous mixture flowing at elevated temperature from the outlet end of the catalyst structure; (b) a homogeneous combustion zone comprising an enclosed space in fluid communication with the catalyst structure and located immediately downstream from the outlet end of the catalyst structure; and (c) a means for inducing recirculation into the partially-combusted mixture flowing through the homogeneous combustion zone whereby homogeneous combustion of the partially-combusted mixture is stabilized within the region of recirculation and complete combustion of the partially-combusted mixture is promoted with the homogeneous combustion zone.

Claim 27

The reaction system of claims 12, 13, 14, 15, 16, 17 or 18, wherein the means for inducing recirculation into the partially-combusted mixture flow is a flameholder positioned downstream from the outlet end of the catalyst structure.

Claim 28

The reaction system of claim 19, wherein the flameholder is selected from a bluff body, a V-gutter, a cone, a perforated plate or a swirler.

Claim 29

The reaction system of claim 20, wherein the flameholder is positioned from about 0.2 to about 20 cm downstream from the outlet end of the catalyst structure.

Claim 30

The reaction system of claim 21, wherein the flameholder provides a geometric flow blockage in the homogeneous combustion zone of from about 10 to about 70 percent.

Claim 31

The reaction system of claims 12, 13, 14 or 16, wherein the catalyst structure is constructed such that between about 10 to about 70 percent of the fuel in the combustible mixture is combusted in the catalyst structure.

Claim 32

The reaction system of claims 12, 13, 14, 15, 16, 17 or 18, wherein the catalyst structure is constructed such that the temperature of the partially-combusted, gaseous mixture flowing out of the outlet end of the catalyst structure is between about 700° and 1000° C.

Claim 33

A process for the combustion of a combustible mixture comprising the steps of: (a) mixing a fuel and an oxygen-containing gas to form a combustible mixture; (b) contacting the mixture with a heat resistant catalyst support composed of a plurality of common walls which form a multitude of adjacently disposed longitudinal channels for passage of the combustible mixture wherein at least a part of the interior surface of at least a portion of the channels is coated with a catalyst for the combustible mixture and the interior surface the remaining channels is not coated with catalyst such that the interior surface of the catalyst-coated channels are in heat exchange relationship with the interior surface of adjacent catalyst-free channels and wherein: (i) the catalyst-coated channels have a higher film heat transfer coefficient (h) than the catalyst-free channels; (ii) the catalyst-coated channels have a smaller average D h than the catalyst-free channels; and (iii) the catalyst-coated channels form a more tortuous flow passage for the combustible mixture than the flow passage formed by the catalyst-free channels; thereby combusting a portion of the combustible mixture to afford a partially-combusted, gaseous mixture; and (c) passing the partially-combusted, gaseous mixture to a homogeneous combustion zone equipped with a flameholder to erect recirculation of at least a portion of the partially-combusted mixture such that homogeneous combustion is stabilized within the region of recirculation and essentially complete combustion of the partially-combusted mixture is obtained.

Claim 34

A process for the combustion of a combustible mixture comprising the steps of: (a) mixing a fuel and an oxygen-containing gas to form a combustible mixture; (b) contacting the mixture with a heat resistant catalyst support composed of a plurality of common walls which form a multitude of adjacently disposed longitudinal channels for passage of the combustible mixture wherein at least a part of the interior surface of at least a portion of the channels is coated with a catalyst for the combustible mixture and the interior surface the remaining channels is not coated with catalyst such that the interior surface of the catalyst-coated channels are in heat exchange relationship with the interior surface of adjacent catalyst-free channels and wherein: (i) the catalyst-coated channels have a higher film heat transfer coefficient (h) than the catalyst-free channels; (ii) the catalyst-coated channels have a smaller average D h than the catalyst-free channels; and (iii) the catalyst-coated channels form a more tortuous flow passage for the combustible mixture than the flow passage formed by the catalyst-free channels; thereby combusting a portion of the combustible mixture to afford a partially-combusted, gaseous mixture; and (c) passing the partially-combusted, gaseous mixture to a homogeneous combustion zone equipped with a flameholder to erect recirculation of at least a portion of the partially-combusted mixture such that homogeneous combustion is stabilized within the region of recirculation and essentially complete combustion of the partially-combusted mixture is obtained.

Claim 35

A process for the combustion of a combustible mixture comprising the steps of: (a) mixing a fuel and an oxygen-containing gas to form a combustible mixture; (b) contacting the mixture with a heat resistant catalyst support composed of a plurally of common walls which form a multitude of adjacently disposed longitudinal channels for passage of the combustible mixture wherein at least a part of the interior surface of at least a portion of the channels is coated with a catalyst for the combustible mixture and interior surface of the remaining channels is not coated with catalyst such that the interior surface of the catalyst-coated channels are in heat exchange relationship with the interior surface of adjacent catalyst-free channels and wherein: (i) the catalyst-coated channels have a higher film heat transfer coefficient (h) than the catalyst-free channels; (ii) the catalyst-coated channels have a smaller average D h than the catalyst-free channels; and (iii) the numeric ratio of average D h for the catalyst-coated channels divided by the average D h for the catalyst-free channels is smaller than the numeric ratio of open frontal area of the catalyst-coated channels divided by the open frontal area of the catalyst-free channels; thereby combusting a portion of the combustible mixture to afford a partially-combusted, gaseous mixture; and (c) passing the partially-combusted, gaseous mixture to a homogeneous combustion zone equipped with a flameholder to effect recirculation of at least a portion of the partially-combusted mixture such that homogeneous combustion is stabilized within the region of recirculation and essentially complete combustion of the partially-combusted mixture is obtained.

Claim 36

A process for the combustion of a combustible mixture comprising the steps of: (a) mixing a fuel and an oxygen-containing gas to form a combustible mixture; (b) contacting the mixture with a heat resistant catalyst support composed of a plurally of common walls which form a multitude of adjacently disposed longitudinal channels for passage of the combustible mixture wherein at least a part of the interior surface of at least a portion of the channels is coated with a catalyst for the combustible mixture and interior surface of the remaining channels is not coated with catalyst such that the interior surface of the catalyst-coated channels are in heat exchange relationship with the interior surface of adjacent catalyst-free channels and wherein: (i) the catalyst-coated channels have a higher film heat transfer coefficient (h) than the catalyst-free channels; (ii) the catalyst-coated channels have a smaller average D h than the catalyst-free channels; and (iii) the numeric ratio of average D h for the catalyst-coated channels divided by the average D h for the catalyst-free channels is smaller than the numeric ratio of open frontal area of the catalyst-coated channels divided by the open frontal area of the catalyst-free channels; thereby combusting a portion of the combustible mixture to afford a partially-combusted, gaseous mixture; and (c) passing the partially-combusted, gaseous mixture to a homogeneous combustion zone equipped with a flameholder to effect recirculation of at least a portion of the partially-combusted mixture such that homogeneous combustion is stabilized within the region of recirculation and essentially complete combustion of the partially-combusted mixture is obtained.

Claim 37

The process of claims 25 or 26, wherein the heat transfer surface area between the catalyst-coated channels and the catalyst-free channels divided by the total channel volume in the structure is greater than about 0.5 mm -1 .

Claim 38

The process of claims 25, or 26, wherein the flameholder is selected from a bluff body, a V-gutter, a cone, a perforated plate, a swirler or a means for changing the cross-sectional area of the homogeneous combustion zone in the direction of partially-combusted gas flow or any combustion of these.

Claim 39

The process of claim 27, wherein the flameholder is positioned from about 0.2 to about 20 cm downstream from the outlet end of the catalyst structure.

Claim 40

The process of claim 29, wherein the flameholder provides a geometric flow blockage in the homogeneous combustion zone of from about 10 to about 70 percent.

Claim 41

The process of claim 28, wherein between about 10 to about 70 percent of the fuel in the combustible mixture is combusted in the catalyst structure.

Claim 42

The process of claim 31, wherein the temperature of the partially-combusted, gaseous mixture flowing out of the outlet end of the catalyst structure is between about 700° and 1000° C.