WO2018158599A1

WO2018158599A1 - Pellet furnace equipped with a burner provided with grate and method for the continuous maintenance of burning therein

Info

Publication number: WO2018158599A1
Application number: PCT/HU2018/050013
Authority: WO
Inventors: Zoltán BURJÁN
Original assignee: Mbh Biomassza Kazan Kft
Current assignee: Mbh Biomassza Kazan Kft
Priority date: 2017-03-02
Filing date: 2018-03-01
Publication date: 2018-09-07
Anticipated expiration: 2019-09-02
Also published as: EP3589889A4; HUP1700093A2; EP3589889A1

Abstract

Pellet furnace equipped with a burner provided with grate, comprising a burning space (11) in which the pellets are received on the grate, and an incinerator unit (14) arranged close to the burning space (11), wherein the interior of the burning space (11) designed as a sluice burner comprises a lower grate (12) and an upper grate (13) arranged in different heights, said grates (12, 13) can be removed from the burning space (11) in lateral direction and during such removal of the grates (12, 13) any ash thereon cannot follow the space receiving the lower and upper grates (12, 13), and for receiving the dropping of the collected ash an ash collector is arranged under the burning space (11).

Description

PELLET FURNACE EQUIPPED WITH A BURNER PROVIDED WITH GRATE AND METHOD FOR THE CONTINUOUS MAINTENANCE OF BURNING THEREIN

The invention relates to a pellet furnace equipped with a burner provided with grate, comprising a burning space in which the pellets are received on the grate, and an incinerator unit is arranged close to the burning space. The invention relates also to a method for the continuous operation of the pellet furnace having a sluice burner.

In the operation of pellet furnaces it is an important condition that the burning can be maintained in a continuous way, because the periods in which heating is required are independent from the properties of the furnace. In the burning space of conventional pellet furnaces the pellets are arranged on a grate, and during the burning process ash is formed. In case of high quality pellets and perfect burning the amount of the generated ash is so small that it can drop through the openings of the grate into an ash collector arranged under the burning space.

In case the quality of the pellets is not first class (which is true for a number of pellet types from economic point of view), the grain size of the so developed ash will be larger and the grains cannot penetrate through the holes of the grate, even if the grate is moved from time to time. As a result ash will get accumulated on the grate which blocks the inflow of air into the burning space and sooner or later decreases the quality of the burning or in given cases it can even stop the burning process.

Such a pellet furnace with a single grate is realized in the furnace family sold under the commercial name "P-FI E" manufactured by the German company New Energy GmbH (Gorlitzen- strasse 21, D-83395, Freilassing), in which the afore mentioned problems might take place.

The task of the invention is to improve the conventional pellet furnaces in such a way in which the burning takes place under optimum conditions and for any required duration independent from the quality of the pellets.

The further task of the invention is to provide a method which is capable of the removal of the generated ash also during the burning process.

This task has been solved by providing a pellet furnace equipped with grate, comprising a burning space in which the pellets are received on the grate, and an incinerator unit is arranged close to the burning space, and according to the invention the interior of the burning space comprises a lower grate and an upper grate arranged in different heights, the grates can be removed from the burning space in lateral direction and during such removal of the grates ash cannot enter the space receiving the lower and upper grates, respectively, and for receiving the dropping of the collected ash an ash collector is arranged under the burning space. In a preferred embodiment ash-withholding limiting plates are arranged around the lower and upper grates.

A method has also been provided by the invention for the continuous operation of a pellet furnace equipped with a burner provided with grate, comprising the steps of feeding the pellets from above on a grate, igniting the pellets and letting them burn there, characterized by the steps of feeding the pellets first on a lower grate arranged close to the bottom of a burning space, then in a later phase of the burning introducing an upper grate from lateral direction into the burning space above the lower grate, feeding further pellets on the upper grate, igniting these later fed pellets by the burning pellets on the lower grate, when the pellets on the lower grate have been burnt, removing the lower grate from the burning space in lateral direction and furthering the ash collected on the lower grate to an ash collector arranged under the burning space then returning the lower grate to the burning space in lateral direction, then removing the upper grate from the burning pace in lateral direction, whereby letting the still burning pellets drop on the already cleaned lower grate. When the burning should be stopped no further pellets will be fed, then after the full burning of the pellets on the lower grate it is removed in lateral direction, whereby the ash collected thereon is dropped into the ash collector present under the burning space. When the burning should be started again the aforementioned steps are cyclically repeated following the return of the lower grate.

The solution according to the invention can maintain the burning till any required time in case the aforementioned cyclical movement of the lower and upper grates is maintained.

The invention will now be described in connection with an exemplary embodiment thereof, in which reference will be made to the accompanying drawings. In the drawing:

Fig. 1 shows the sluice burner according to the invention at the initial state of burning;

Fig. 2 shows the sluice burner in the second phase of burning, in which pellets are fed on the upper grate 13;

Fig. 3 shows the third phase of burning, in which the burning has terminated on the lower grate 12;

Fig. 4 shows the fourth phase of burning in which the lower grate 12 is in pulled out state; Fig. 5 shows the fifth phase of the burning, in which the lower grate 12 is arranged again in the burning space in a clean state; and

Fig. 6 shows the end of the cycle which is the same as the beginning thereof.

Fig. 1 shows the schematic perspective view of sluice burner 10 made according to the invention, in which the sectional view of a burning space 11 can be seen that has a lower grate 12 and an upper grate 13, and each grate 12, 13 can be pulled out by respective actuators (not shown) in lateral direction from the region of the burning space 11. The lateral removal of the lower and upper grates 12, 13 from the burning space 11 are limited from above and from below by plates 15, 16 which prevent the generated ash from penetrating into the lateral space. In the drawing the limiting elements and the plates have been shown in a schematic way only and for preserving the visual illustration the ash collector has also not been shown which is arranged under the lower grate 12 of the sluice burner 10, and the ash collector can be removed for being discharged in a manual or automated way. An incinerator unit 14 extends in the burning space 11 in a medium height range, which can be a nozzle in which an electrical heater (incandescent filament) is arranged that heats the temperature of air passed therethrough above the ignition temperature of the pellets.

Fig. 1 shows the sluice burner 10 during operation when the not yet completely burned out pellets burn on the space of the lower grate 12. When the pellets start to burn out, the upper grate 13 will be pushed into the burning space 11 (Fig. 2), whereby the newly fed pellets will drop naturally on the upper grate 13. The burning on the lower grate 12 will ignite these fresh pellets on the upper grate 13 and they will start to burn there. In the state shown in Fig. 2 there will be burning pellets on both grates 12, 13, but the pellets on the lower grate 12 will soon get burned out and ash is formed therefrom. This state is illustrated on Fig. 3 when ash can be seen only on the lower grate 12 but at the same time the later fed pellets still burn well on the upper grate 13.

For the sake of removal the ash present on the lower grate 12 this grate 12 is removed from the burning space 11 as illustrated in Fig. 4 and the ash will automatically fall down in an ash collector placed under the sluice burner 11. In the meantime the fire is still burning on the upper grate 13.

Following the removal of the ash the lower grate 12 can be moved again into its original position as shown in Fig. 5.

In the next step shown in Fig. 6 the upper grate 13 will be pulled out from the burning space 11 in lateral direction and the pellets burning thereon will drop on the lower grate 12, whereby the cycle is completed because on Fig. 6 the position shown in Fig. 1 is obtained again.

The pellet furnace equipped with the burner that comprises the grates according to the invention ensures a continuous and efficient burning by the discrete removal of the generated ash (which adversely affects the burning in conventional burners and decreases efficiency) because the pellets will burn on always clean grates without the presence of excess ash under optimum circumstances.

Claims

Claims:

1. Pellet furnace equipped with a burner provided with grate, comprising a burning space (11) in which the pellets are received on the grate, and an incinerator unit (14) arranged close to the burning space (11), characterized in that the interior of the burning space (11) designed as a sluice burner comprises a lower grate (12) and an upper grate (13) arranged in different heights, said grates (12, 13) can be removed from the burning space (11) in lateral direction and during such removal of the grates (12, 13) any ash thereon cannot follow the space receiving the lower and upper grates (12, 13), and for receiving the dropping of the collected ash an ash collector is arranged under the burning space (11).

2. The pellet furnace as claimed in claim 1, wherein ash withholding limiting plates (15, 16) are arranged around the lower and upper grates (12, 13).

3. Method for the continuous operation of a pellet furnace equipped with a burner provided with grate, comprising the steps of feeding the pellets from above on a grate, igniting the pellets and letting them burn there, characterized by the steps of feeding the pellets first on a lower grate (12) arranged close to the bottom of a burning space (11), then in a later phase of the burning introducing an upper grate (13) from lateral direction into the burning space (11) above the lower grate (12), feeding further pellets on the upper grate (13), igniting these later fed pellets by the burning pellets on the lower grate (12), when the pellets on the lower grate (12) have been burnt, removing the lower grate (12) from the burning space (12) in lateral direction and furthering the ash collected on the lower grate (12) to an ash collector arranged under the burning space (11), then returning the lower grate (12) to the burning space (11) in lateral direction, then removing the upper grate (11) from the burning pace (11) in lateral direction, whereby letting the still burning pellets drop on the already cleaned lower grate (12).

4. The method as claimed in claim 3, wherein following the full burning of the pellets on the lower grate (12) and when the burning is desired to be stopped, the lower grate (12) is removed from the burning space (11), whereby the ash collected thereon is dropped into an ash collector arranged under the burning space (11), and when a new burning should be started, the aforementioned steps are repeated following the return of the lower grate (12).