DE102023204058A1 - Air-gas mixture combustion plant with one combustion unit - Google Patents

Abstract

In an air-gas mixture combustion system (100) with a combustion unit (120) which has a burner body (122) with a burner surface (124) for burning a combustible air-gas mixture (130), and with an air-gas mixing unit (110) for mixing air with gas to produce the combustible air-gas mixture (130), the air-gas mixing unit (110) has a mixing body (112) which is arranged at least in regions in the burner body (122); a gas inflow element (114) which is arranged at least in regions in the mixing body (112) and which forms with the mixing body (112) an annular gas outlet opening (115) for a gas stream (132) flowing into the mixing body (112); and an air guide element (116) which is arranged at least in part in the mixing body (112) and forms with the mixing body (112) an annular air flow guide channel (140) for an air flow (134) flowing into the mixing body (112).

Description

State of the art

The present invention relates to an air-gas mixture combustion plant with a combustion unit having a burner body with a burner surface for burning a combustible air-gas mixture, and with an air-gas mixing unit for mixing air with gas to produce the combustible air-gas mixture.

From the WO 2023/275564 A1 Such an air-gas mixture combustion system with a combustion unit is known, which has a burner body with a burner surface for burning a combustible air-gas mixture. The air-gas mixture combustion system is assigned an air-gas mixing unit for mixing air with gas to produce the combustible air-gas mixture. The air-gas mixing unit comprises a mixing body, which is arranged in the burner body, and a gas inflow element, which is arranged in some areas in the mixing body.

disclosure of the invention

The present invention relates to an air-gas mixture combustion system with a combustion unit that has a burner body with a burner surface for burning a combustible air-gas mixture, and with an air-gas mixing unit for mixing air with gas to produce the combustible air-gas mixture. The air-gas mixing unit has a mixing body that is arranged at least in part in the burner body; a gas inflow element that is arranged at least in part in the mixing body and forms with the mixing body an annular gas outlet opening for a gas flow flowing into the mixing body; and an air guide element that is arranged at least in part in the mixing body and forms with the mixing body an annular air flow guide channel for an air flow flowing into the mixing body.

This makes it possible to provide an air-gas mixture combustion system with a combustion unit and an air-gas mixing unit in a simple manner, in which a compact structure can be achieved by the air-gas mixing unit arranged at least substantially within the combustion unit. This makes it possible to reduce the corresponding volume of a combustible air-gas mixture generated in each case. Furthermore, the gas outlet opening can advantageously be formed by the gas inflow element on the inner circumference of the mixing body, so that the gas flow flowing into the mixing body flows around the air flow flowing into the mixing body. This makes it possible to reduce a respective pressure drop at a corresponding mixing point in the air-gas mixing unit, so that the functional performance of the air-gas mixing unit is improved and a reduced gas inlet pressure can be used.

Preferably, the mixing body has a cylindrical tube.

This makes it possible to provide a mixing body with a comparatively simple geometric structure, so that the manufacturing costs for the air-gas mixing unit can advantageously be reduced.

According to one embodiment, the air guiding element is cone-shaped.

This makes it possible to provide a cost-effective and robust air guiding element.

Preferably, the cone-shaped air guide element has a decreasing diameter starting from the gas inflow element in the direction of the flowing air stream.

In this way, the required widening of the air flow guide channel starting from the gas outlet opening in the mixing body can be easily achieved.

According to one embodiment, the gas inflow element is annular and the gas outlet opening is arranged on an inner circumference of the mixing body.

This makes it possible to provide a simple and uncomplicated gas inlet element with which a safe and reliable positioning of the gas outlet opening on the inner circumference of the mixing body can be achieved.

Preferably, the air guiding element extends through the ring-shaped gas inflow element, and the ring-shaped air flow guide channel extends at least in sections between the gas inflow element and the air guiding element.

This makes it possible to easily form the annular air flow guide channel between the air guide element and the gas outlet opening.

Preferably, the gas outlet opening has an opening width of maximum 0.6 mm.

The provision of the gas outlet opening with an opening width of a maximum of 0.6 mm advantageously enables the formation of a flashback arrester, in particular in the event that the gas stream flowing into the mixing body contains hydrogen, since the extinguishing distance of hydrogen is greater than 0.6 mm depending on a respective temperature of the burner body or the burner surface.

Preferably, the burner body is cylindrical.

This makes it possible to provide a burner body with a comparatively simple geometric structure.

Preferably, the burner surface is arranged on the outer circumference of the cylindrical burner body.

In this way, safe and reliable combustion of each generated combustible air-gas mixture can be achieved.

Preferably, the gas stream flowing through the annular gas outlet opening into the mixing body comprises hydrogen.

Thus, the air-gas mixture combustion system according to the invention can advantageously be used to burn a combustible air-hydrogen mixture. The gas stream flowing into the mixing body can contain pure hydrogen or only consist partially of hydrogen.

Short description of the drawings

• 1 eine perspektivische Ansicht einer beispielhaften Luft-Gas-Gemisch-Verbrennungsanlage mit einer Verbrennungseinheit und einer Luft-Gas-Mischeinheit,
• 2 eine Vorderansicht der Luft-Gas-Gemisch-Verbrennungsanlage von 1,
• 3 eine Schnittansicht durch die Luft-Gas-Gemisch-Verbrennungsanlage von 1 und 2, gesehen entlang einer Schnittlinie III-III von 2, und
• 4 eine Schnittansicht durch die Luft-Gas-Gemisch-Verbrennungsanlage von 1 bis 3, gesehen entlang einer Schnittlinie IV-IV von 2.

The invention is explained in more detail in the following description using embodiments shown in the drawings. They show:

• 1 a perspective view of an exemplary air-gas mixture combustion plant with a combustion unit and an air-gas mixing unit,
• 2 a front view of the air-gas mixture combustion plant of 1 ,
• 3 a sectional view through the air-gas mixture combustion plant of 1 and 2 , seen along a section line III-III of 2 , and
• 4 a sectional view through the air-gas mixture combustion plant of 1 until 3 , seen along a section line IV-IV of 2 .

Description of the embodiments

In the figures, elements with the same or comparable function are provided with identical reference symbols and are described in more detail only once.

1 shows an exemplary air-gas mixture combustion system 100 for burning an air-gas mixture. The air-gas mixture combustion system 100 can be used in any application that requires the use of a heat exchanger. For example, the air-gas mixture combustion system 100 can be used in a building heating system or a water heater.

Illustratively, the air-gas mixture combustion plant 100 has an air-gas mixing unit 110 for mixing air with gas to produce a combustible air-gas mixture, and a combustion unit 120 for burning the combustible air-gas mixture produced by the air-gas mixing unit 110. In addition, the air-gas mixture combustion plant 100 can have a heat exchanger 105.

To provide gas for the air-gas mixing unit 110, the air-gas mixture combustion plant 100 may have an external gas inlet 107. To provide air for the air-gas mixing unit 110, the air-gas mixture combustion plant 100 may have an external air inlet 109. The external air inlet 109 may be connected to a fan 108.

Illustratively, the external gas inlet 107 and the external air inlet 109 are connected to a burner hood 121, which is assigned to the combustion unit 120. The burner hood 121 can be integrated into a burner door 102, which is attached to the heat exchanger 105, for example.

The burner hood 121 is preferably designed to supply air from the external air inlet 109 and gas from the external gas inlet 107 to the air-gas mixing unit 110. The gas can be any gas, such as hydrogen, propane, butane, methane, liquefied petroleum gas, etc. However, the gas preferably contains at least a portion of hydrogen.

For example, the gas can have a certain gas quality range. The gas quality range can be specified by a respective gas distributor. Thus, in addition to the pure fuel itself, the gas can contain other, normally non-combustible substances. These other substances in the gas are called impurities. Typical contaminants are nitrogen or carbon dioxide.

A corresponding density and viscosity of the pure fuel differ from the density and viscosity of the typical impurities. If the gas quality changes within the limits permitted by the gas quality standards, the concentration of impurities in the gas changes. This leads to a change in the density and viscosity of the gas and thus a respective flow rate of the gas supplied to the air-gas mixing unit 110. This in turn changes the heat input and the air-gas ratio of the air-gas mixture combustion plant 100. The greater the difference in density and viscosity between the gas before the gas quality change and after the gas quality change, the greater the change in the heat input and the air-gas ratio of the air-gas mixture combustion plant 100 at the time of the gas quality change.

The air-gas mixing unit 110 is preferably designed to produce a homogeneous air-gas mixture. The air-gas mixing unit 110 can be designed as a single-stage air-gas mixing unit, as in 3 and 4 shown as an example.

2 shows the air-gas mixture combustion plant 100 with the air-gas mixing unit 110 and the combustion unit 120 of 1 The combustion unit 120 is assigned the burner hood 121, which is integrated into the burner door 102. The burner door 102 is attached, for example, to the heat exchanger 105.

In particular, 2 an exemplary arrangement of the outer gas inlet 107 and the outer air inlet 109 on the burner hood 121, which enables a compact construction of the burner hood 121. Furthermore, 2 an exemplary arrangement of the fan 108 of 1 under the heat exchanger 105.

3 shows the air-gas mixture combustion plant 100 with the air-gas mixing unit 110 and the combustion unit 120 of 1 and 2 The air-gas mixing unit 110 has a mixing body 112, a gas inflow element 114 and an air guide element 116. The combustion unit 120 is according to. 1 and 2 the burner hood 121 assigned to the gem. 1 and 2 the external air inlet 109 is connected. The air-gas mixing unit 110 and the combustion unit 120 are illustratively at least partially in the heat exchanger 105 of 1 and 2 arranged.

The combustion unit 120 comprises a burner body 122 with a burner surface 124. The burner body 122 is preferably cylindrical and is illustratively connected to the burner hood 121 in a fluid-tight manner by a suitable seal 125, e.g. an annular O-seal. The burner surface 124 is preferably arranged on an outer circumference 129 of the cylindrical burner body 122.

The mixing body 112 of the air-gas mixing unit 110 is arranged at least in part in the burner body 122. The mixing body 112 preferably has a cylindrical tube.

Illustratively, the mixing body 112 has a funnel-shaped extension extending into the burner hood 121. This is preferably connected to the burner hood 121 in a fluid-tight manner by a suitable seal 111, e.g. an annular O-seal.

The gas inflow element 114 of the air-gas mixing unit 110 is arranged at least in part in the mixing body 112 and forms with the mixing body 112 an annular gas outlet opening 115 for a gas stream 132 flowing into the mixing body 112, which preferably contains at least a portion of hydrogen. The gas inflow element 114 is preferably annular and the gas outlet opening 115 is preferably arranged on an inner circumference 113 of the mixing body 112.

Illustratively, the gas inflow element 114 is funnel-shaped and extends into the burner hood 121. The gas inflow element 114 is preferably connected to the burner hood 121 in a fluid-tight manner by a suitable seal 118, e.g. an annular O-seal.

The air guide element 116 of the air-gas mixing unit 110 is preferably also arranged at least in part in the mixing body 112 and forms with the mixing body 112 an annular air flow guide channel 140 for an air flow 134 flowing into the mixing body 112. The air flow 134 is supplied to the mixing body 112 via the burner hood 121 from the external air inlet 109. The annular air flow guide channel 140 extends illustratively over the entire length of the air guide element 116 and thus at least in sections between the gas inflow element 114 and the air guide element 116.

Preferably, the air guide element 116 is designed in a pin-shaped manner and extends through the ring-shaped gas inflow element 114. The pin-shaped air guide element 116 has illustratively starting from the gas inflow element 114, or at least starting from the gas outlet opening 115, in the direction of the flowing air stream 134, it has a decreasing diameter 117. Thus, the entire air flow guide channel 140 can be designed analogously to the air flow guide channel of a Venturi nozzle.

During operation of the air-gas mixture combustion system 100, the gas flow 132 and the air flow 134 are fed to the air-gas mixing unit 110. The air-gas mixing unit 110 mixes the gas flow 132 with the air flow 134 and thus produces a combustible air-gas mixture 130. In this case, the arrangement of the air-gas mixing unit 110 in the burner body 122 advantageously produces a comparatively small volume of the combustible air-gas mixture 130, so that the effects of a possible flashback during combustion can at least be reduced. The combustible air-gas mixture 130 flows from the air-gas mixing unit 110 into the burner body 122 of the combustion unit 120 and is burned by the latter on the burner surface 124. In this case, the arrangement of the air-gas mixing unit 110 in the burner body 122 can reduce the flow path to be covered by the combustible air-gas mixture 130 from the mixing body 112 to the burner surface 124, whereby a respective flow duration can also be reduced. In particular, the flow path can be designed to be relatively free of turbulence. This enables improved combustion control by means of associated control algorithms of the air-gas mixture combustion system 100, whereby improved control of an air-gas ratio in the combustible air-gas mixture 130 is enabled.

4 shows the air-gas mixture combustion plant 100 with the air-gas mixing unit 110 and the combustion unit 120 of 1 until 3 , which are arranged at least partially in the heat exchanger 105. The air-gas mixing unit 110 has the mixing body 112, the gas inflow element 114 and the air guide element 116 according to 3 The combustion unit 120 comprises the burner body 122 with the burner surface 124 of 3 In addition, the combustion unit 120 is assigned the burner hood 121, on which, according to 1 and 2 the external gas inlet 107 is connected.

4 illustrates the exemplary sealing of the burner body 122 on the burner hood 121 by the seal 125, the exemplary sealing of the mixing body 112 on the burner hood 121 by the seal 111, and the exemplary sealing of the gas inflow element 114 on the burner hood 121 by the seal 118. For this purpose, the burner hood 121 illustratively has an annular groove 126 in which the seal 125 is arranged. Furthermore, the burner hood 121 has, for example, an outer limiting ring 128 against which the seal 111 is applied, as well as an inner, annular web against which the seal 118 is applied.

In addition, 4 the air flow guide channel 140, which extends over the entire length of the air guide element 116 and thus at least in sections between the gas inflow element 114 and the air guide element 116, as well as the annular gas outlet opening 115 formed between the gas inflow element 114 and the mixing body 112 for the gas flow 132 flowing into the mixing body 112. The gas outlet opening 115 preferably has an opening width 119 of a maximum of 0.6 mm. This means that when hydrogen is used in the flowing gas flow 132 during combustion, the occurrence of a flashback through the gas outlet opening 115 can be ruled out, since the extinguishing distance of hydrogen is greater than 0.6 mm depending on the respective temperature of the burner body 122 or the burner surface 124, so that the safety during combustion can be increased.

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions.

Cited patent literature

• WO 2023/275564 A1 [0002]

Claims (10)

Air-gas mixture combustion system (100) with a combustion unit (120) which has a burner body (122) with a burner surface (124) for burning a combustible air-gas mixture (130), and with an air-gas mixing unit (110) for mixing air with gas to produce the combustible air-gas mixture (130), wherein the air-gas mixing unit (110) has: a mixing body (112) which is arranged at least in regions in the burner body (122); a gas inflow element (114) which is arranged at least in regions in the mixing body (112) and forms with the mixing body (112) an annular gas outlet opening (115) for a gas stream (132) flowing into the mixing body (112); and an air guide element (116) which is arranged at least in part in the mixing body (112) and forms with the mixing body (112) an annular air flow guide channel (140) for an air flow (134) flowing into the mixing body (112). Air-gas mixture combustion plant according to claim 1 , wherein the mixing body (112) has a cylindrical tube. Air-gas mixture combustion plant according to claim 1 or 2 , wherein the air guiding element (116) is pin-shaped. Air-gas mixture combustion plant according to claim 3 , wherein the cone-shaped air guide element (116) has a decreasing diameter (117) starting from the gas inflow element (114) in the direction of the flowing air stream (134). Air-gas mixture combustion plant according to one of the preceding claims, wherein the gas inflow element (114) is annular, and wherein the gas outlet opening (115) is arranged on an inner circumference (113) of the mixing body (112). Air-gas mixture combustion plant according to claim 5 , wherein the air guide element (116) passes through the annular gas inflow element (114), and wherein the annular air flow guide channel (140) extends at least in sections between the gas inflow element (114) and the air guide element (116). Air-gas mixture combustion plant according to one of the preceding claims, wherein the gas outlet opening (115) has an opening width (119) of a maximum of 0.6 mm. Air-gas mixture combustion plant according to one of the preceding claims, wherein the burner body (122) is cylindrical. Air-gas mixture combustion plant according to claim 8 , wherein the burner surface (124) is arranged on the outer circumference (129) of the cylindrical burner body (122). Air-gas mixture combustion plant according to one of the preceding claims, wherein the gas stream (132) flowing through the annular gas outlet opening (115) into the mixing body (112) comprises hydrogen.

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