WO2023173152A1

WO2023173152A1 - Incinerator system

Info

Publication number: WO2023173152A1
Application number: PCT/AT2023/060072
Authority: WO
Inventors: Alfred Beilschmidt; Armin SAGEDER; Markus Leopold; Norbert Josef DAMBOECK
Original assignee: Alfred Beilschmidt
Priority date: 2022-03-16
Filing date: 2023-03-14
Publication date: 2023-09-21
Also published as: AT526024A1

Abstract

The invention relates to an incinerator system for burning biomass, in particular wood pellets, comprising a combustion chamber (1) with a nozzle bottom (2) above which a fluidized bed (3) comprising a bulk quantity of solid particles, preferably quartz sand, is arranged, an ignition unit (4), a combustion air supply (5) and a fuel supply (6). The ignition unit (4) comprises two ignition electrodes (7) or a spark plug for generating an arc, the tips of the two ignition electrodes (7) or the tip of the spark plug being arranged in the combustion chamber (1) in the vertical direction above the fluidized bed (3), which is stationary in the switched-off state, and substantially below an inlet opening (8) of the fuel supply (6).

Description

INCINERATION FURNACE SYSTEM

Technisches GebietTechnical area

The invention relates to an incineration furnace system for the combustion of biomass, in particular wood pellets, comprising a combustion chamber with a nozzle base, above which a fluidized bed made of a bed of solid particles, preferably quartz sand, is arranged, an ignition unit, a combustion air supply, and a fuel supply.

Stand der TechnikState of the art

Incinerator systems with fluidized beds are usually used in large systems, for example in power plants, and are operated around the clock. However, in the area of small systems, for example for heating, hot water preparation and power generation for single-family homes, the systems do not run permanently but rather cyclically and therefore have to be re-ignited again and again. In the

E.P

2827059

A

An example of such an incinerator system for use in the private sector is described. Here, the air supplied for the starting process is preheated, for example by an electric hot air dryer, in order to reach the ignition temperature for the fuel.

With automatic ignition, the ignition of biomass in pellet stoves is usually carried out with heating resistors or with hot air. The igniters used require around 600 to 1000 W and are subject to a lot of wear due to the high temperature.

The

EN

20321670

U

shows a burner for pellet fuel, which is ignited with a discharge electrode in a guide tube. The electrodes themselves remain at a distance from the pellets. The construction is correspondingly complex and unsuitable for use in a fluidized bed combustion chamber.

Darstellung der ErfindungPresentation of the invention

The object of the present invention is to improve an incineration furnace system, as described for example in EP 2827059 A1, in such a way that the ignition process, which is often required in private use, can be carried out in a significantly more energy efficient manner. The device should be simple and inexpensive to construct and have a long service life with little need for maintenance.

This object is achieved according to the invention in that: the ignition unit comprises two ignition electrodes or a spark plug for generating an arc, the tips of the two ignition electrodes or the tip of the spark plug in the combustion chamber being arranged in the vertical direction above the fluidized bed which is at rest in the switched off state and essentially below an inlet opening of the fuel supply. In the proposed solution, the tips of the ignition electrodes or the tip of the spark plug protrude directly into the combustion chamber and generate an arc when voltage is applied. The fuel, which is introduced into the combustion chamber via the fuel supply, comes to rest on the stationary fluidized bed exactly between the two ignition electrodes or near the tip of the spark plug and is ignited by the plasma of the arc. For example, only around 150 W is required for the ignition device in order to safely ignite the fuel.

It is a further preferred feature that the tips of the ignition electrodes or the tip of the spark plug lie within the moving fluidized bed during operation of the combustion furnace system. As soon as the combustion furnace system is started, the surface of the fluidized fluidized bed, which is now flushed with air, is higher than the surface of the resting fluidized bed and also flows around the tips of the ignition electrodes or the tip of the spark plug. This has the advantage that any soot produced during the ignition process is removed from the tips of the ignition electrodes by the solid particles of the fluidized bed and the ignition electrodes are therefore always completely soot-free and clean with every new starting process, which means they also need to be serviced less frequently.

It is also a preferred feature that the inlet opening of the combustion air supply is also arranged essentially above the tips of the ignition electrodes or the tip of the spark plug and the incoming air flow is thus aligned essentially normally to the surface of the fluidized bed which is at rest in the switched off state. On the one hand, the combustion air introduced facilitates the ignition process and extends the arc towards the fluidized bed so that the resulting plasma can efficiently surround and ignite the fuel provided.

Finally, it is a further preferred feature that a control unit is provided, via which the starting process can be controlled when the combustion furnace system is put into operation, with the control unit first directing fuel into the combustion chamber for the starting process, which comes to rest on the resting fluidized bed, then via the Ignition electrodes or an arc is generated via the spark plug, which ignites the fuel located between the tips of the ignition electrodes or near the tip of the spark plug, whereby the combustion air supply can optionally be controlled via the control unit in order to stretch the arc in the direction of the fluidized bed through the incoming air flow, and wherein after the fuel has been ignited, the ignition electrodes or the spark plug can be deactivated again by the control unit and the air supply through the nozzle base can be activated in order to set the fluidized bed in motion. It is advantageous to regulate the entire starting process via an appropriate control unit. This means that individual parameters for the respective system can be saved and adjusted if necessary. Possible adjustable parameters would be the amount of fuel introduced, the ignition duration, the amount and speed of the combustion air introduced, the time at which the air supply is switched on through the nozzle base to fluidize the fluidized bed, etc.

Kurze Beschreibung der ZeichnungenBrief description of the drawings

The invention will now be described in detail using an exemplary embodiment and with the help of the accompanying figures. Show it
Fig. 1 is a schematic side sectional view through the combustion chamber of an incinerator system according to the invention and
Fig. 2 is a schematic cross-sectional view through the combustion chamber of an incinerator system according to the invention.

Weg(e) zur Ausführung der ErfindungWay(s) for carrying out the invention

In Fig. 1, a combustion chamber 1 of an incineration furnace system according to the invention is shown very schematically in a side sectional view. In the combustion chamber 1 there is a fluidized bed 3, shown here in the switched off state, which is formed from a bed of, for example, quartz sand. Below the fluidized bed 3 there is a nozzle base 2 which is connected to an air supply 9 via a large number of openings. The air supply 9 serves to fluidize the fluidized bed 3 and to supply combustion air during operation of the system. The air supply 9 is arranged on the outside along the combustion chamber 1 so that the incoming air is preheated accordingly via heat exchanger surfaces before entering through the nozzle base 2.

An ignition unit 4 is arranged above the fluidized bed 3, the tips of the ignition electrodes 7 lying above the surface of the stationary fluidized bed 3. Directly above the tips of the ignition electrodes 7 is the inlet opening 8 for the fuel supply 6, through which fuel is introduced in the form of, for example, wood pellets. In the example shown, the combustion air supply 5 is also guided into the combustion chamber 1 via the same pipe as the fuel supply 6 with a common inlet opening 8.

In Fig. 2, the system from Fig. 1 is shown in a schematic cross-sectional view in the area of the common pipe of the combustion air supply 5 and fuel supply 6. It goes without saying that the fuel supply 6 can also be designed separately and the combustion air supply 5 can, for example, be arranged next to it or in a ring around it.

When the system is switched off, the fuel introduced comes to rest in the area between the tips of the ignition electrodes 7. When the ignition electrodes 7 are switched on, an arc is created between the two tips, with the resulting plasma being blown towards the fuel or the surface of the fluidized bed 3 by the air introduced via the combustion air supply 5 and thus efficiently igniting the fuel.

Significantly less energy is used for the ignition process than with conventional ignition devices. As soon as enough fuel has been ignited, the fluidized bed 3 can be started. Due to the movement of the sand bed of the fluidized bed 3, the tips of the ignition electrodes 7 get into the fluidized bed 3 and are freed from any soot that may have arisen during the ignition process, so that they are completely cleaned again during the next ignition process and thus remain unrestricted in their function even with frequent ignition processes.

Claims

Combustion furnace system for the combustion of biomass, in particular wood pellets, comprising a combustion chamber (1) with a nozzle base (2), above which a fluidized bed (3) made of a bed of solid particles, preferably quartz sand, is arranged, an ignition unit (4), a combustion air supply (5), as well as a fuel supply (6), characterized in that the ignition unit (4) comprises two ignition electrodes (7) or a spark plug for generating an arc, the tips of the two ignition electrodes (7) or the tip of the spark plug in the Combustion chamber (1) is arranged in the vertical direction above the fluidized bed (3) which is at rest in the switched off state and essentially below an inlet opening (8) of the fuel supply (6).
Incinerator system according to claim 1, characterized in that the tips of the ignition electrodes (7) or the tip of the spark plug lie within the moving fluidized bed (3) during operation of the incinerator system.
Combustion furnace system according to claim 1 or 2, characterized in that the inlet opening of the combustion air supply (5) is also arranged essentially above the tips of the ignition electrodes (7) or the tip of the spark plug and the incoming air flow is therefore essentially normal to the surface of the switched off State resting fluidized bed (3) is aligned.
Incinerator system according to one of claims 1 to 3, characterized in that a control unit is provided, via which the starting process can be controlled when the incinerator system is put into operation, the control unit first directing fuel into the combustion chamber (1) for the starting process, which is on the resting fluidized bed (3) comes to rest, then an arc is generated via the ignition electrodes (7) or via the spark plug, which ignites the fuel located between the tips of the ignition electrodes (7) or near the tip of the spark plug, whereby the combustion air supply (if necessary via the control unit ( 5) can be controlled in order to stretch the arc in the direction of the fluidized bed (3) through the incoming air flow, and after the fuel has been ignited, the ignition electrodes (7) or the spark plug can be deactivated again by the control unit and the air supply through the nozzle base ( 2) can be activated to set the fluidized bed (3) in motion.