DE102022102753A1 - Procedure for starting up a heater, computer program, regulation and control unit, heater and use of a throttle device - Google Patents

Abstract

A method for starting up a heater (1) is presented, having a delivery device (2) for delivering a fuel-air mixture to a burner (3) of the heater (1) and a throttle device (6), comprising at least the following steps: a) Commissioning of the conveyor (2) with a target output (14), b) moving the throttle device (6) to an ignition position, c) igniting the burner (3) of the heater (1), d) opening the throttle device (6). It has been shown that the influence of disturbances, such as wind, blockages in the exhaust gas path, etc., when operating the delivery device (2) with (significantly) higher power combined with a throttling (reduction) of the volume flow to an ignition volume flow through the throttling device (6), can be significantly reduced. In this way, the required ignition volume flow can be provided with a significantly lower influence of disturbances.

Description

The invention relates to a method for starting up a heating device, a computer program, a regulation and control device, a heating device and the use of a throttle device.

To start up a heater, a delivery device is usually run or set to a defined output so that it feeds a predetermined mixture of fuel and combustion air to a burner and then the fuel/combustion air mixture exiting the burner is immediately ignited by an ignition device can.

As part of the avoidance of fossil fuels, hydrogen or mixtures containing hydrogen are increasingly being used as fuel for heaters. However, hydrogen as a fuel has significantly different properties compared to conventional fuels, such as natural gas, during combustion, in particular a significantly increased flame speed, a significantly smaller standard gap width and an increased pressure increase gradient. This can lead to explosions when the heater is started up, even if the ignition delay time is very short, which can result in a loss of comfort for the user and/or damage to the heater.

According to the prior art, a heater operated with hydrogen is ignited when the combustion mixture has a high lambda value in conjunction with a low output of the heater, ie a low ignition volume flow of the combustion mixture delivered to the burner. For this purpose, a conveying device conveying the combustion mixture is operated with low power, for example a fan with a low speed.

The influence of disturbances, such as pressure fluctuations in the system, for example caused by blockages in the exhaust gas path and/or wind in the area of the combustion air supply or the exhaust system, on the (low) ignition volume flow is problematic. This influence can have significant effects and thus even further promote the occurrence of the problems mentioned during an ignition process.

Proceeding from this, it is the object of the invention to propose a method for starting up a heating device which at least partially overcomes the problems of the prior art described. In particular, a safe start-up of a heating device operated with hydrogen or with a mixture containing hydrogen is to be made possible.

In addition, the invention should at least not significantly increase the complexity of a heating device and only require minor structural changes to a heating device and enable simple integration into an existing production process.

These objects are solved by the features of the independent patent claims. Further advantageous refinements of the solution proposed here are specified in the dependent patent claims. It is pointed out that the features listed in the patent claims can be combined with one another in any technologically sensible manner and define further refinements of the invention. In addition, the features specified in the patent claims are specified and explained in more detail in the description, with further preferred configurations of the invention being presented.

1. a) Inbetriebnahme der Fördereinrichtung mit einer Sollleistung,
2. b) Fahren der Drosseleinrichtung auf eine Zündposition,
3. c) Zünden des Brenners des Heizgerätes,
4. d) Öffnen der Drosseleinrichtung.

Contributing to this is a method for starting up a heater, at least having a delivery device for delivering a fuel-air mixture to a burner of the heater and a throttle device, comprising at least the following steps:

1. a) Commissioning of the conveyor with a target output,
2. b) moving the throttle device to an ignition position,
3. c) igniting the burner of the heater,
4. d) opening the throttle device.

Steps a), b), c) and d) can be carried out at least once in the specified sequence in a regular operating procedure. In particular, steps a) and b) can (partially or completely) be carried out synchronously or at the same time, or step b) can also be carried out before step a). The method is used in particular for a safe start of a heating device operated with hydrogen.

The heater is in particular a gas heater which is set up to burn a gaseous fuel, in particular hydrogen or a gas mixture containing hydrogen, with the supply of ambient air (as combustion air) in order to provide heat, for example for a heating circuit or a hot water supply. The heater can usually have at least one burner and a conveyor Mixture of fuel (gas) and combustion air conveys through a mixture duct of the heater to the burner. The combustion products can then be routed through an exhaust duct of the heater to an exhaust system.

When the heater is started up, an ignition volume flow of a fuel/air mixture can be conveyed to the burner of the heater and ignited there by an ignition device. The ignition device can generate an ignition spark or be a hot-surface igniter, which is able to ignite a combustion mixture through an ignitable surface temperature.

The conveying device can in particular be a blower, the power of which can be controlled or specifically adjusted using a (blower) speed. The delivery device can be arranged in particular in the mixture channel of the heater. Alternatively, the conveying device can be arranged at a different position in the flow path of the heater, for example in the exhaust gas duct.

The heater can have an electronic or pneumatic gas/air combination, for example.

In an electronic gas-air network, the mixing ratio of fuel and combustion air can be controlled via an (electronically) controlled gas valve and flame monitoring in the combustion chamber, such as an ionization electrode or a measurement of the ultraviolet radiation of the flame.

The invention is particularly suitable for use in connection with a pneumatic gas-air combination. In the case of a pneumatic gas-air combination, a predetermined volume flow of fuel (combustion gas) can be supplied to a supplied volume flow of combustion air via a pneumatic device, for example a Venturi nozzle. The specified disturbances, such as wind, etc., which lead to an increase in the supplied volume flow of combustion air, would (also) result in an increase in the supplied quantity of fuel in a pneumatic gas-air combination. This increased amount of fuel can lead to irregularities in the ignition process and pose a safety risk.

The throttle device, often also referred to as a throttle flap or designed as such, can be set up to reduce the flow cross section available for the gas flow (and possibly also to increase it again) and thus reduce the volume flow delivered (by the delivery device) to a Limit ignition volume flow. When the throttle device is fully open, it can be set up in such a way that the gas flow is not influenced (hindered). In particular, the throttle device can be opened and closed by a motor and can be controlled via an electrical signal. The throttle device thus makes it possible to limit a volume flow conveyed by the conveying device to a (predefined, reduced) ignition volume flow and thus to operate the conveying device with a higher (target) output during the commissioning of the heater.

The throttle device can be arranged at various positions in or on the heater.

The throttle device can be arranged, for example, in the mixture channel of the heater (in the direction of flow before and/or behind the delivery device). In this case, fuel (for example hydrogen) can flow around the throttle device. The throttle device itself and any devices connected thereto, such as an electrical switch and/or a pressure sensor for monitoring them, can thus be designed with increased safety requirements in order to prevent fuel from escaping or igniting in the area of the throttle device. In the case of a pneumatic gas-air combination, the arrangement of the throttle device in the mixture channel does not lead to an additional negative pressure at the gas valve (Venturi nozzle), which means that there is practically no influence on the composition of the mixture.

The throttle device can be assigned to a combustion air supply (also referred to as an air duct) and/or can be arranged where no contact with fuel can occur and thus increased safety requirements for the throttle device and possibly associated devices can be dispensed with. A pneumatic gas-air connection can be influenced by the negative pressure that occurs and would have to be taken into account when supplying gas, for example by influencing the gas valve of the pneumatic mixture preparation by a motor.

The throttle device can be arranged in the exhaust path (exhaust duct or exhaust system). The throttle device and possibly a connected device must then be adapted to the high prevailing temperatures of the exhaust gases and also to the corrosive conditions (caused by the condensate contained in the exhaust gas). However, all components in the flow path that are upstream of the throttle device in the direction of flow would be at the same height ren (triggered by the throttle device) to interpret pressure.

An ignition volume flow can characterize a volume flow of combustion mixture (mixture of hydrogen and combustion air) that is suitable for an ignition process of the heater.

It has been shown that the influence of disturbances, such as wind, blockages in the exhaust gas path, etc., can be significantly reduced when the delivery device is operated at (significantly) higher power combined with a throttling of the volume flow to an ignition volume flow through the throttling device. In other words, the required ignition volume flow can be provided with a significantly lower influence of disturbances and thus with significantly lower tolerances.

According to step a), the conveyor device can be put into operation with a (specified) target output. In this case, the setpoint power can (without the action of the throttle device) promote a volume flow which is considerably above the ignition volume flow. In particular, the setpoint power (when the throttle device is open) can promote a volume flow that is in a range between twice (2 times) and six times (6 times) the ignition volume flow.

According to step b), the throttle device can be driven or moved and/or adjusted into a (predefined) ignition position. The ignition position can characterize an opening width of the throttle device, which reduces the delivered volume flow to the ignition volume flow when the delivery device is operated with the target output.

According to step c), the burner can be ignited. An ignition device of the heater can be put into operation for this purpose. Step c) should be coordinated with the execution of steps a) and b) in order to ensure a reliable ignition process.

According to an advantageous embodiment, the emergence of a flame and thus the success of the ignition process can be checked/monitored by means of a flame monitor during or after the implementation of step c). The flame monitor can include, for example, a UV sensor (sensor for detecting ultraviolet radiation), which can detect the UV radiation emitted by a (hydrogen) flame.

According to step d), the throttle device can now be opened (completely) and the heater can be operated according to the heat requirement (in normal operation).

According to a further advantageous embodiment, the function of the throttle device can be checked as part of the implementation of step b), in particular whether the ignition position has been correctly approached by the throttle device. This can be done, for example, by a positioning switch that monitors the opening position of the throttle device and/or makes (or opens) an electrical contact when the ignition position is reached. Alternatively or cumulatively, a pressure drop could also be detected, for example by appropriately arranged pressure sensors. Last but not least, the ignition volume flow that occurs can also be checked/monitored by means of a device for detecting a volume flow.

According to a further aspect, a computer program is also proposed which is set up to (at least partially) carry out a method presented here. In other words, this relates in particular to a computer program (product) comprising instructions which, when the program is executed by a computer or a regulation and control device for a heating device, cause a method proposed here to be carried out.

According to a further aspect, a machine-readable storage medium is also proposed, on which the computer program is stored. The machine-readable storage medium is usually a computer-readable data carrier.

According to a further aspect, a regulating and control unit for a heating device is also proposed, set up to carry out a method proposed here. For this purpose, the regulating and control device can have a processor, for example, and/or have it at its disposal. In this context, the processor can, for example, execute the method stored in a memory (of the regulation and control device). Advantageously, operating data and reference values (for example an ignition volume flow and/or a setpoint power) for carrying out a method presented here can also be stored in the memory of the regulation and control unit.

According to a further aspect, a heater is also proposed, having a regulation and control device proposed here. The heater is in particular a gas heater, in particular a hydrogen-powered gas heater. The gas heater may have a burner and a conveyor with which a mixture of combustion gas (hydrogen) and combustion air can be supplied to the burner.

According to a further aspect, the use of a throttle device for starting up a heating device is proposed. In particular, the throttle device can be used to reduce a volume flow delivered by a delivery device to an ignition volume flow.

The details, features and advantageous configurations discussed in connection with the method can accordingly also occur in the computer program presented here, the regulation and control device, the heating device and/or the use and vice versa. In this respect, full reference is made to the statements there for a more detailed characterization of the features.

An arrangement of a burner and a UV sensor, a combustion chamber and a heating device is thus specified here, which at least partially solves the problems described with reference to the prior art. In particular, the arrangement of a burner and a UV sensor, the combustion chamber and the heater at least contribute to enabling reliable flame monitoring of a burner of a heater for the entire modulation range with just one UV sensor.

In addition, the invention can be implemented in a particularly simple manner since only one throttle device has to be provided in comparison to a heating device or burner according to the prior art.

• 1: einen Ablauf eines hier vorgeschlagenen Verfahrens,
• 2: Parameterverläufe, die sich bei Durchführung eines hier vorgeschlagenen Verfahrens einstellen können, und
• 3: ein hier vorgeschlagenes Heizgerät.

The invention and the technical environment are explained in more detail below with reference to the accompanying figures. It should be pointed out that the invention should not be restricted by the exemplary embodiments given. In particular, unless explicitly stated otherwise, it is also possible to extract partial aspects of the facts explained in the figures and to combine them with other components and findings from the present description. In particular, it should be pointed out that the figures and in particular the proportions shown are only schematic. Show it:

• 1 : a sequence of a method proposed here,
• 2 : Parameter curves that can occur when carrying out a method proposed here, and
• 3 : a heater proposed here.

1 showed an exemplary and schematic sequence of a method proposed here. The method is used to safely start up a heating device 1. The sequence of steps a), b), c) and d) shown in blocks 110, 120, 130 and 140 can occur in a regular operating sequence.

3 shows an example and diagrammatically of a heater 1 proposed here. This can suck in/promote combustion air via a combustion air supply 4 through a conveyor 2 and add a gas, for example hydrogen, to the intake volume flow of combustion air via a gas valve 5 . The combustion mixture of gas and combustion air can now be fed via a mixture channel 16 to a burner 3 arranged in a combustion chamber 8 . A throttle device 6 can be arranged in the mixture channel 16 and can limit a flow cross section of the mixture channel 16 . The combustion products can be fed from the combustion chamber 8 to an exhaust system 10 via an exhaust gas duct 9 . In addition, the heater 1 on the combustion chamber 8 can include a UV sensor 13 for monitoring a flame of the burner 3 . Protected from the high temperatures in the combustion chamber 8, the UV sensor 13 can be arranged outside the combustion chamber 8. In 2 shows a heater 1 with an electronic gas-air combination, in which an electrically controllable gas valve 5 can be controlled, among other things, by a signal from the UV sensor 13 . The invention can nevertheless be used very well in connection with a pneumatic gas-air combination, in which case the gas valve 5 could then be designed as a Venturi nozzle which would add fuel in a self-adjusting manner depending on the volume flow of combustion air flowing past.

A regulation and control unit 7 can be set up to carry out a method presented here. For this purpose, the regulation and control device 7 can be electrically connected to the delivery device 2 , the throttle device 6 , the gas valve 5 and the UV sensor 13 .

In block 110, according to step a), the conveyor device 2 can be put into operation with a target output. In this case, the setpoint power can (with the throttle device 6 open) promote a volume flow which is considerably higher than an ignition volume flow suitable for an ignition process.

In block 120, according to step b), the throttle device 6 can be moved to an ignition position. In doing so, it can reduce the flow cross-section of the mixture channel 16 and thus adjust the volume flow flowing through to an ignition volume flow. Optionally, in block 120, this could be achieved Chen the ignition position are checked or evaluated by a positioning switch, based on a pressure drop at the throttle device 6 (for example, by pressure sensors) and / or using a flow sensor.

In block 130, according to step c), the burner 3 can be ignited. For this purpose, an ignition device can be put into operation, which can ignite the gas mixture emerging from the burner 3 .

In block 140, according to step d), the throttle device 6 can be opened (completely) and the heater 1 can switch to normal operation.

According to a preferred embodiment, the presence of a flame can be monitored by means of the UV sensor 13 while step c) (block 130) is being carried out. 2 FIG. The diagram shown illustrates the relationship between a pressure loss Δ P and the volumetric flow V delivered.

A pressure loss 11 in the system (total of heater 1 and exhaust system 10) with an open throttle device 6 or without it can be subject to the influence of disruptive factors 12. A pressure loss 15 can occur for the system when the throttle device 6 is closed, with an influence of disruptive factors 20 . An influence of disruptive factors 12, 20 can, for example, be the effect of a gust of wind in the area of the outlet opening of the exhaust system 10, the influence of disruptive factors 12 when the throttle device 6 is open and the influence of disruptive factors 20 when the throttle device 6 is closed can be the same.

A pressure loss curve 19 of the delivery device 2 can provide an ignition volume flow 21 when the throttle device 6 is open. A pressure loss curve 14 of the delivery device 2 can provide an ignition volume flow 21 when the throttle device 6 is closed, in which case the output of the delivery device 2 can be significantly higher for the pressure loss curve 14 in order to compensate for the increased pressure loss 15 (of the system) with the throttle device 6 closed and the same ignition volume flow 21 as with an open throttle device 6 (pressure loss curve 19 in connection with pressure loss 11 of the system). The influence of the disruptive factors 20 results in a significantly lower tolerance range 17 of the ignition volume flow 21 when the throttle device 6 is closed compared to a tolerance range 18 (of the ignition volume flow 21) when the throttle device 6 is open.

Reference List

1

heater

2

conveyor

3

burner

4

supply of combustion air

5

gas valve

6

throttle device

7

regulation and control unit

8th

combustion chamber

9

exhaust duct

10

exhaust system

11

pressure drop

12

Influence of disruptive factors

13

UV sensor

14

Pressure drop curve conveyor

15

pressure drop

16

mixture channel

17

tolerance range

18

tolerance range

19

Pressure drop curve conveyor

20

Influence of disruptive factors

21

ignition flow rate

Claims (11)

Method for starting up a heater (1), at least having a delivery device (2) for delivering a fuel-air mixture to a burner (3) of the heater (1) and a throttle device (6), the method comprising at least the following steps: a) commissioning of the conveyor (2) with a target output (14), b) moving the throttle device (6) to an ignition position, c) ignition of the burner (3) of the heater (1), d) opening the throttle device (6). procedure after claim 1 , wherein the target output (14) of the delivery device (2) delivers a volume flow which is greater than an ignition volume flow suitable for an ignition process, and the ignition position of the throttle device (6) reduces the volume flow delivered by the delivery device (2) to an ignition volume flow suitable for an ignition process reduced. A method according to any one of the preceding claims, wherein the fuel is hydrogen. Method according to one of the preceding claims, wherein the throttle device (6) is fully opened in step d). Method according to one of the preceding claims, wherein in step a) the delivery device (2) is put into operation with a target output (14) which, when the throttle device (6) is open, delivers a volume flow which corresponds to twice to six times the ignition volume flow. Method according to one of the preceding claims, wherein a pressure drop across the throttle device (6) is determined in step e). Computer program comprising instructions which cause a regulation and control device (7) of a heating device (1) to carry out a method according to one of the preceding claims. Regulating and control device (7), set up to carry out a method according to one of Claims 1 until 6 . Heater (1), having a regulation and control unit (7). claim 8 . heater (1) after claim 9 , wherein the heater (1) has a throttle device (6) in a mixture channel (16). Use of a throttle device (6) for starting up a heater (1).

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