EP2985529B1

EP2985529B1 - Combustion system and method for operating the same

Info

Publication number: EP2985529B1
Application number: EP14180981.4A
Authority: EP
Inventors: Piet Blaauwwiekel; Radovan Bakos
Original assignee: Honeywell Technologies SARL
Current assignee: Garrett Motion SARL
Priority date: 2014-08-14
Filing date: 2014-08-14
Publication date: 2020-01-01
Anticipated expiration: 2034-08-14
Also published as: EP2985529A1

Description

The present patent application relates to a combustion system and to a method for operating a combustion system.
Combustion systems comprising a plurality of gas burners and a common exhaust pipe for the plurality of gas burners are known from the prior art.
DE 10 2010 054 807 A1 discloses a combustion system comprising a plurality of gas burners and a common exhaust pipe for the plurality of gas burners, wherein all gas burners are positioned within a common combustion chamber so that the combustion system provides a single boiler having several gas burners. During burner-on phases of the gas burners of the combustion system gas and air are provided to the gas burners by fans sucking in the gas and the air. During burner-on phases the gas becomes combusted resulting in exhaust gas that flows into the common exhaust pipe. During burner-off phases of the gas burners of the combustion system no gas and air are provided to the gas burners. According to DE 10 2010 054 807 A1 the gas burners of the combustion system will only combust gas in case all fans are running.
EP 2 428 732 A2 discloses a combustion system comprising a single boiler with a single gas burner being positioned in the combustion chamber of the boiler. An exhaust gas sensor is assigned to an exhaust pipe of the boiler. The signal provided by the exhaust gas sensor is used to perform a combustion adaption for the gas burner.
When such a combustion adaption based on a signal provided by an exhaust sensor shall be performed for a combustion system comprising a plurality of gas burners, it is according to the prior art necessary to assign to each gas burner an individual exhaust sensor. However, such exhaust sensors are expensive.
A combustion system according to the preamble of claim 1 is disclosed in US 2010/0330512 A1 . A combustion system according to the preamble of claim 2 is disclosed in NL 6610804 .
Against this background, a novel combustion system and method for operating the combustion system are provided.
The combustion system is defined in claim 1 or in claim 2.
The invention allows a combustion adaption for a combustion system comprising a plurality of gas burners based on a signal provided by a common exhaust sensor. It is no longer necessary to have for each gas burner of the combustion system an individual exhaust sensor. The number of exhaust gas sensors and thereby the costs for a combustion system comprising a plurality of gas burners can be reduced.
In an operating status of the combustion system in which more than one gas burner of the plurality of gas burners is in a burner-on phase the signal provided by the common exhaust gas sensor is not used for combustion adaption.
The method for operating the combustion system is defined in claim 5.
Preferred developments of the invention are provided by the dependent claims and the description which follows. Exemplary embodiments are explained in more detail on the basis of the drawing, in which:

Figure 1: shows a schematic view of a combustion system according to a first embodiment of the invention in a first operating status of the same;
Figure 2: shows the combustion system of Figure 1 in a second operating status of the same;
Figure 3: shows a schematic view of a combustion system according to a second embodiment of the invention in a first operating status of the same;
Figure 4: shows the combustion system of Figure 3 in a second operating status of the same; and
Figure 5: shows a schematic view of a combustion system according to a third embodiment of the invention.

The invention relates to a combustion system and to a method for operating a combustion system.
Figures 1 and 2 both show a first embodiment of a combustion system 10 according to the present invention. The combustion system 10 of Figures 1 and 2 comprises a plurality of gas burners 11a, 11b, 11c.
Each gas burner 11a, 11b, 11c is is positioned within an individual combustion chamber 12a, 12b, 12c so that the combustion systems 10 comprises a plurality of boilers 13a, 13b, 13c each having one gas burner 11a, 11b, 11c.
The combustion system 10 further comprises a common exhaust pipe 14 for the plurality of gas burners 11a, 11b, 11c. Each boiler 13a, 13b, 13c communicates with the common exhaust pipe 14 in such a way that exhaust gas resulting from a combustion of gas with the combustion chamber 12a, 12b, 12c of the respective boiler 13a, 13b, 13c is directed into the common exhaust pipe 14.
During burner-on phases of a respective gas burner 11a, 11b, 11c gas and air are provided to the respective gas burner 11a, 11b, 11c. The gas becomes combusted by the respective gas burner 11a, 11b, 11c resulting in exhaust gas. The exhaust gas of each gas burner 11a, 11b, 11c and thereby of each boiler 13a, 13b, 13c flows into the common exhaust pipe 14.
During burner-off phases of a respective gas burner 11a, 11b, 11c no gas is provided to the respective gas burner 11a, 11b, 11c. So during burner-off phases no gas becomes combusted.
In a transitional phase when no gas is provided to the respective gas burner 11a, 11b, 11c air can be provided to the same for pre-purge and post-purge to clean the respective combustion chamber 12a, 12b, 12c before and after a burner-on phase.
In Figure 1 the gas burner 11b of boiler 13b is in a burner-on phase while the gas burners 11a, 11c of boilers 13a, 13c are in a burner-off phase.
In Figure 2 the gas burners 11b, 11c of boilers 13b, 13c are in a burner-on phase while the gas burner 11a of boiler 13a is in a burner-off phase.
A valve 17a, 17b, 17c is assigned to each boiler 13a, 13b, 13c so that in a burner-off phase of the respective gas burner 11a, 11b, 11c the combustion chamber 12a, 12b, 12c of the respective boiler 13a, 13b, 13c can be separated from the common exhaust pipe 14 by closing the respective valve 17a, 17b, 17c. In a burner-on phase of a boiler 13a, 13b, 13c the respective valve 17a, 17b, 17c is opened allowing the exhaust gas to flow into the common exhaust pipe 14. In a burner-off phase of a boiler 13a, 13b, 13c the respective valve 17a, 17b, 17c is closed preventing a back flow of exhaust gas from the common exhaust pipe 14 into the combustion chamber 12a, 12b, 12c of the respective boiler 13a, 13b, 13c. In a transitional phase when only air can may be provided to the combustion chamber 12a, 12b, 12c for pre-purge and post-purge purposes the respective valve 17a, 17b, 17c is opened allowing to clean the respective combustion chamber 12a, 12b, 12c.
The combustion system 10 shown in Figures 1 and 2 further comprises a common controller 15 for all gas burners 11a, 11b, 11c or all boilers 13a, 13b, 13c. Such a controller controls each boiler 13a, 13b, 13c individually.
A common exhaust gas sensor 16 is assigned to the common exhaust pipe 14. The exhaust gas sensor 16 analyses the exhaust gas. E.g., the exhaust gas sensor 16 can be a CO-sensor or CO_e-sensor or O₂-sensor. The exhaust gas sensor 16 provides a signal to the controller 15.
In an operating status of the combustion system 10 in which only a single gas burner 11a or 11b or 11b of the plurality gas burners 11a, 11b, 11c is in a burner-on phase (see Figure 1) while all other gas burners are in a burner-off phase - meaning also that no one of the other gas burners is in a transitional phase - the signal provided by the common exhaust gas sensor 16 is used by the controller 15 for a combustion adaption at least at the gas burner 11a or 11b or 11c being in the burner-on phase. Said combustion adaption can be performed to compensate for a changing gas quality. Details of such an adaption are known from the prior art document EP 2 428 732 A2 .
In an operating status of the combustion system 10 in which more than one gas burner of the plurality gas burners 11a, 11b, 11c is in a burner-on phase (see Figure 2) or in which only one a single gas burner 11a or 11b or 11b is in a burner-on phase while at least one other gas burners is in a transitional phase, the signal provided by the common exhaust gas sensor 16 is not used by the controller 15 for a combustion adaption.
In an operating status of the combustion system 10 in which more than one gas burner of the plurality gas burners 11a, 11b, 11c is in a burner-on phase (see Figure 2), the signal provided by the common exhaust gas sensor 16 can be used for other functions of the controller like safety functions.
According to a first alternative, in an operating status of the combustion system 10 in which only a single gas burner of the plurality gas burners 11a, 11b, 11c is in a burner-on phase while all other gas burners are in a burner-off phase - meaning also that no one of the other gas burners is in a transitional phase - the signal provided by the common exhaust gas sensor 16 is used for an combustion adaption only at the gas burner being in the burner-on phase.
According to a second alternative, in said operating status of the combustion system 10 the signal provided by the common exhaust gas sensor 16 will be used for an combustion adaption at all gas burners of the combustion system 10. E.g. a full adaption can be performed for the gas burner being in a burner-on phase while for the other gas burners being in a burner-off phase a preliminary adaption using the results of the full adaption can be performed.
When all gas burners are in a burner-off phase or in a transitional phase, the signal provided by the common exhaust gas sensor is not used for combustion adaption.
Figures 3 and 4 both show a second embodiment of a combustion system 10 according to the present invention. The combustion system 10 of Figures 3 and 4 differs from the combustion systems of Figures 1 and 2 only by the feature that in Figure 3 and 4 each boiler 13a, 13b, 13c is controlled by an individual controller 15a, 15b, 15c. The controller 15a receives the signal from with the exhaust gas sensor 16 and acts as a master controller for the other controllers 15b, 15c. In all other details the combustion system 10 of Figures 3 and 4 corresponds to the combustion systems of Figures 1 and 2. Especially, in an operating status of the combustion system 10 in which only a single gas burner 11a or 11b or 11c of the plurality gas burners 11a, 11b, 11c is in a burner-on phase while all other gas burners are in a burner-off phase - meaning also that no one of the other gas burners is in a transitional phase - (see Figure 3) the signal provided by the common exhaust gas sensor 16 is used by the controllers 15a, 15c, 15c for a combustion adaption at least at the gas burner 11a or 11b or 11c being in the burner-on phase. However, in an operating status of the combustion system 10 in which more than one gas burner of the plurality gas burners 11a, 11b, 11c is in a burner-on phase (see Figure 4) or in which only one a single gas burner 11a or 11b or 11b is in a burner-on phase while at least one other gas burners is in a transitional phase, the signal provided by the common exhaust gas sensor 16 is not used by the controllers 15a, 15b, 15c for a combustion adaption.
Figure 5 shows a third embodiment of a combustion system 20 according to the present invention. The combustion system 20 of Figure 5 comprises a plurality of gas burners 21a, 21b positioned within a common combustion chamber 22 so that the combustion system 20 provides a single boiler 23 having several gas burners 21a, 21b positioned in the common combustion chamber 22. The combustion system 20 further comprises a common exhaust pipe 24 for the plurality of gas burners 21a, 21b. Each gas burner 21a, 21b of the boiler 23 communicates with the common exhaust pipe 24 in such a way that exhaust gas resulting from combustion of gas at the respective gas burners 21a, 21b is directed into the common exhaust pipe 24.
During burner-on phases of a respective gas burner 21a, 21b gas and air are provided to the respective gas burner 21a, 21b by a fan 28a, 28b sucking in gas and air. The gas becomes combusted by the respective gas burner 21a, 21b resulting in exhaust gas. The exhaust gas of each gas burner 21a, 21b flows into the common exhaust pipe 24. During burner-off phases of a respective gas burner 21a, 21b no gas is provided to the respective gas burner 21a, 21b. In Figure 5 the gas burner 21a is in a burner-on phase while the gas burner 21b is in a burner-off phase.
A valve 27a, 27b is assigned to each gas burner 21a, 21b. In a burner-on phase of a gas burner 21a, 21b the respective valve 27a, 27b is opened so that gas and air can be provided to the respective gas burner 21a, 21b by the respective fan 28a, 28b. In a burner-off phase a gas burner 21a, 21b the respective valve 27a, 27b is closed preventing a back flow of exhaust gas from the common combustion camber 22 in the direction of the respective fan 28a, 28b of the respective gas burner 21a, 21b. The combustion system 20 shown in Figure 5 further comprises controllers 25a, 25b for the gas burners 21a, 21b. Each controller 25a, 25b controls the respective gas burner 21a, 21b individually. The two controllers 25a, 25b can be part of a single controller controlling both gas burners 21a, 21b. A common exhaust gas sensor 26 is assigned to the common exhaust pipe 24. The exhaust gas sensor 26 analyses the exhaust gas. E.g., the exhaust gas sensor 26 can be a CO-sensor or COe-sensor or O2-sensor. The exhaust gas sensor 26 provides a signal to the controllers 25a, 25b.
In an operating status of the combustion system 20 in which only a single gas burner 21a or 21b of the plurality gas burners is in a burner-on phase while all other gas burners are in a burner-off phase (see Figure 5) - meaning also that no one of the other gas burners is in a transitional phase - the signal provided by the common exhaust gas sensor 26 is used for a combustion adaption at least at the gas burner 2a, 21b being in the burner-on phase.
However, in an operating status of the combustion system 20 in which more than one gas burner of the plurality gas burners 21a, 21b is in a burner-on phase (not shown) or in which only one a single gas burner is in a burner-on phase while at least one other gas burners is in a transitional phase, the signal provided by the common exhaust gas sensor 26 is not used for a combustion adaption.
The invention uses a system architecture for a cascade of parallel running gas burners using one exhaust gas sensor to provide combustion adaption. The exhaust gas sensor is assigned to a common exhaust pipe of the gas burners. Only when a single gas burner is running, the signal provided by the common exhaust gas sensor is used for combustion adaption. The invention allows a reduction of costs of such combustion systems.
The combustion adaption can be performed when only a single gas burner is in a burner-on phase. It is possible to passively wait for such an operation status of the combustion system. Alternatively, it is possible that the respective controller actively initiates such an operation status of the combustion system in defined time intervals or based on events trigged by an internal algorithm. The respective controller knows the state of other gas burners and ensures that other gas burners are not interfering with the gas burner performing optimization procedure, so that the valves are closed, no pre-purge or post-purge is running and there is sufficient timeout after these actions to guarantee no in-mix of air or other gases into the common exhaust pipe during the sensor signal of the common exhaust gas sensor is used for the combustion adaption.

List of reference signs

10: combustion system
11a: gas burner
11b: gas burner
11c: gas burner
12a: combustion chamber
12b: combustion chamber
12c: combustion chamber
13a: boiler
13b: boiler
13c: boiler
14: exhaust pipe
15: controller
15a: controller
15b: controller
15c: controller
16: exhaust gas sensor
17a: valve
17b: valve
17c: valve

20: combustion system
21a: gas burner
21b: gas burner
22: combustion chamber
23: boiler
24: exhaust pipe
25a: controller
25b: controller
26: exhaust gas sensor
27a: valve
27b: valve
28a: fan
28b: fan

Claims

Combustion system (10) comprising a plurality of gas burners (11a, 11b, 11c) and a common exhaust pipe (14) for the plurality of gas burners, wherein during burner-on phases of a respective gas burner (11a, 11b, 11c) gas is combusted by the same resulting in exhaust gas that flows into the common exhaust pipe (14), and wherein during burner-off phases of a respective gas burner (11a) no gas is combusted by the same,
wherein each gas burner (11a, 11b, 11c) is positioned within an individual combustion chamber (12a, 12b, 12c) so that the combustion systems (10) provides a plurality of boilers (13a, 13b, 13c),

wherein each gas burner (11a, 11b, 11c) and thereby each boiler (13a, 13b, 13c) directs in the burner-on phase of the respective gas burner the exhaust gas into the common exhaust pipe (14);

the combustion system further comprising

a valve (17a, 17b, 17c) assigned to each boiler (13a, 13b, 13c) so that in a burner-off phase of the respective gas burner (11a, 11b, 11c) the combustion chamber (12a, 12b, 12c) of the respective boiler (13a, 13b, 13c) can be separated from the common exhaust pipe (14) by closing the respective valve (17a, 17b, 17c) and a controller (15a, 15b, 15c) assigned to each gas burner (11a, 11b, 11c),

characterized in that

a common exhaust gas sensor (16) is assigned to the common exhaust pipe (14),

in an operating status of the combustion system (10) in which only a single gas burner of the plurality gas burners (11a, 11b, 11c) is in a burner-on phase while all other gas burners are in a burner-off phase, the controller (15a, 15b, 15c) of the gas burner being in the burner-on phase is configured to use the signal provided by the common exhaust gas sensor (16) for a combustion adaption
Combustion system comprising a plurality of gas burners (21a, 21b) and a common exhaust pipe (24) for the plurality of gas burners, wherein during burner-on phases of a respective gas burner (21a, 21b) gas is combusted by the same resulting in exhaust gas that flows into the common exhaust pipe (24), and wherein during burner-off phases of a respective gas burner (21a, 21b) no gas is combusted by the same,
wherein the gas burners (21a, 21b) are positioned within a common combustion chamber (22) so that the combustion systems (20) provides a single boiler (23) having several gas burners (21a, 21b),

wherein a valve (27a, 27b) is assigned to each gas burner (21a, 21b) so that in a burner-off phase of the respective gas burner (21a, 21b) the valve (27a, 27b) assigned to the respective gas burner (21a, 21b) can be closed,

wherein a common exhaust gas sensor (26) is assigned to the common exhaust pipe (24),

characterized by

a plurality of controllers (25a, 25b) for controlling the gas burners (21a,21b),

wherein the respective controller (25a, 25b) is configured such that the valve (27a, 27b) assigned to respective gas burner (21a, 21b) can be closed thereby preventing a backflow of exhaust gas over the respective gas burner (21a, 21b),

wherein the respective controller (25a, 25b) is configured such that in an operating status of the combustion system (20) in which only a single gas burner of the plurality gas burners (21a, 21b) is in a burner-on phase while all other gas burners are in a burner-off phase the signal provided by the common exhaust gas sensor (26) is used for a combustion adaption at least at the gas burner being in the burner-on phase.
Combustion system as claimed in claim 1 or 2, characterized in that in an operating status of the combustion system in which only a single gas burner of the plurality gas burners is in a burner-on phase while all other gas burners are in a burner-off phase the signal provided by the common exhaust gas sensor is used for an combustion adaption only at the gas burner being in the burner-on phase.
Combustion system as claimed in claim 1 or 2, characterized in that in an operating status of the combustion system in which only a single gas burner of the plurality gas burners (is in a burner-on phase while all other gas burners are in a burner-off phase the signal provided by the common exhaust gas sensor is used for an combustion adaption at all gas burners of the combustion system.
Method for operating a combustion system (10; 20) according to one of claims 1 to 4, wherein
in an operating status of the combustion system (10; 20) in which only a single gas burner of the plurality gas burners (11a, 11b, 11c; 21a, 21b) is in a burner-on phase while all other gas burners are in a burner-off phase the signal provided by a common exhaust gas sensor (16; 26) being assigned to the common exhaust pipe (14; 24) is used for an combustion adaption at least at the gas burner being in the burner-on phase.
Method as claimed in claim 5, characterized in that in an operating status of the combustion system (10; 20) in which only a single gas burner of the plurality gas burners (11a, 11b, 11c; 21a, 21b) is in a burner-on phase while all other gas burners are in a burner-off phase the signal provided by the common exhaust gas sensor (16; 26) is used for an combustion adaption only at the gas burner being in the burner-on phase.
Method as claimed in claim 5, characterized in that in an operating status of the combustion system (10; 20) in which only a single gas burner of the plurality gas burners (11a, 11b, 11c; 21a, 21b) is in a burner-on phase while all other gas burners are in a burner-off phase the signal provided by the common exhaust gas sensor (16; 26) is used for an combustion adaption at all gas burners of the combustion system.