WO1995010007A1 - Method and device for controlling the consumption of solid fuels in a combustion unit - Google Patents

Abstract

The invention concerns a method in which the carbonization gases produced immediately above the burner outlet area are led up across the inner wall (2) of the feed chamber (1), between the feed chamber and the combustion chamber (3), and across the roof of the feed chamber in one or more ducts (14) between the outer feed-chamber wall (12) and the oven wall (13) as a downdraft to the firebed. The device designed to carry out this method has, located above the burner outlet (5), a cover plate (6) which screens off the burner outlet to prevent carbonization gases which form above the burner outlet from passing through the outlet and/or, located in the feed-chamber roof, a duct (19) which connnects the upper part of the feed chamber roof with the duct(s) running between the feed chamber and the oven wall and which leads the carbonization gases formed immediately above the burner outlet into the downdraft of mixed carbonization gas and air in the duct(s), the duct in the feed-chamber roof optionally being connected to a fresh-air feed (18) and/or the duct(s) between the feed chamber and the oven wall optionally being connected to a fresh-air feed.

Description

 Method and device for controlling the combustion of solid fuels in one

 Incinerator.

The invention relates to a method for controlling the combustion of solid fuels in a solid fuel combustion system, in which the carbonization gases formed in the filling space from the ceiling area of the full space via at least one channel provided between an outer wall of the filling chamber and a furnace wall as a downflow in the lower area of the full space into the

Clut bed of the full room can be returned.

In the incineration plant described in OE-PS 26 48 732, the filling shaft is separated by a wall from a combustion chamber connected downstream of the filling shaft, which is connected to the filling shaft via a passage opening, the so-called combustion outlet. Furthermore, at least one channel runs between the furnace wall and the filling shaft, the lower end of which via a passage with the lower region of the filling shaft and the upper one End communicates with the upper filling shaft area via a further passage. The channels are over the

 upper passage «in carbonization gas-air mixture, which flows downward as a downward flow in the channel or channels

 and is fed via the lower passage to the ember bed located in the area of the grate for combustion.

However, the combustion behavior in this known filling shaft combustion furnace is not yet satisfactory, since the cooler carbonization gases which form in the region of the combustion outlet adversely affect the combustion. Some of the cooler carbonization gases flow directly through the

 Firing outlet into the combustion chamber. As a result, complete combustion of the carbonization gases is not possible. Furthermore, the fuel burns up on the opposite side of the combustion passage. In order to remedy the resulting negative effects on the combustion and to achieve a satisfactory burn-up of the fuel, it was previously necessary to intensify the air-gas mixture before the combustion exit, which in turn led to a

 faster burning in this area led to one

 So-called empty fire resulted, in which the supplied air gas mixture, without flowing through the ember bed, came directly into the exhaust gas flow.

The object of the present invention is now to find measures which make it possible that the carbonization gases which form and flow in the area of the combustion outlet no longer flow down through the combustion outlet.

According to the method of the invention, the

Smoldering gases are formed lengthways above the combustion exit area the inner wall of the filling chamber running between the filling chamber and the combustion chamber is directed upwards and fed along the ceiling area of the filling chamber in the channels between the outer wall of the filling chamber and the furnace wall as a downward flow to the ember bed.

 In this case, the flow pattern of the carbonization gases is preferably effected by supplying fresh air with an injector effect in the ceiling area of the filling space and / or by the falling flow of the carbonization gases in the channel or channels carrying the carbonization gas downflow, if appropriate with additional fresh air supply having an injector effect.

A device suitable for carrying out the method according to the invention is characterized in that a canopy shielding the opening of the combustion outlet against the passage of carbonization gases forming above the combustion outlet is arranged above the combustion outlet and / or that a channel (hereinafter) is located in the ceiling area of the filling chamber

 Filling chamber cover channel) is located, the upper

 Connects the area of the filling chamber with the channel (s) running between the filling chamber and the furnace wall and introduces the carbonization gases that form directly above the combustion outlet into the downward flow of the carbonization gas / air mixture in the channel or channels, the filling chamber cover channel provided in the ceiling area of the filling chamber possibly having a

Fresh air supply is connected and / or if necessary the channel or channels between the filling chamber and the furnace wall are connected to a fresh air supply.

This means that two constructive measures are suitable for carrying out the method, each of which is used on its own to improve the existing combustion process to a certain extent runs leads, but combined with each other, lead to an optimization of the burning process.

With the help of the first characteristic feature of the invention, that arranged in a above the combustion exit

 Covering the combustion outlet, it can be achieved that the cooler smoldering gases formed at the combustion outlet no longer reach the combustion chamber through the combustion outlet and pollute the exhaust air supplied to the chimney. In addition, the chimney draft is better fed to the ember bed due to the roofing of the firing outlet, which ensures even combustion.

Due to the second characteristic feature of the invention, which consists in a channel provided in the ceiling area of the filling space, which is the upper area of the filling space

 connects with the channel or channels running between the filling chamber and furnace wall, it is achieved that the

 In the area of the combustion outlet wall, the smoldering gases that arise, flow upwards in the filling chamber due to the pressure conditions that build up, and are fed through the filling chamber cover channel to the downward flow of the smoldering gas / air mixture that is conducted downwards in the outer channel or channels and together with this into the smoothing bed for post-combustion

be fed.

The efficiency of this second characteristic feature of the invention, which is an alternative to the roofing of the

Brennsusganges can be used, can be significantly improved if either the filling chamber cover channel

is connected to a fresh air supply or the

Outside channels are provided with a fresh air supply, or if both measures are used together. However, the method according to the invention is most effectively solved by the combination of the two characteristic device features discussed above.

According to a preferred embodiment, the roof of the combustion exit is designed as a glow element. This brings the cool carbonization gases that form at the combustion outlet to a higher temperature. The combustible materials lying on the incandescent body thus produce hot ones

 Smoldering gases that flow upwards, i.e. continue from the combustion exit.

The canopy is preferably formed by one or more closed plates. The canopy is expediently arranged on the firing outlet wall running obliquely downwards.

The roof can also be designed as a cast or stone block.

According to a further preferred feature of the invention, in order to be able to better lead the hot carbonization gases that arise above the combustion outlet, preferably above the incandescent body, along the combustion outlet wall

a guide wall is provided at a distance from the combustion exit wall in the interior of the filling shaft, which is preferably designed as a folding wall. A flow channel is created through this guide wall, through which the hot smoldering gases are directed upwards.

The fresh air supply provided by the device according to the invention in the ceiling area of the filling chute can be used Improvement of the flow rate of the carbonization gases can be supplied with injector action. Correspondingly, the fresh air can also be fed into the outer channels with an injector effect.

The always necessary pressure compensation in the ceiling area

the filling shaft takes place independently of the fresh air supply mentioned above.

Further preferred features of the object of the application result from the subclaims and from the following description of exemplary embodiments with reference to the drawing, in which:

Fig. 1 with a manhole combustion furnace

 multivalent combustion of gas or oil in the

 Section in which a roof of the combustion aisle as well as a filling duct cover duct with

 Fresh air supply under the effect of an injector and one running along the combustion outlet wall

 Folding wall are provided,

 Fig. 2 shows a room stove, in which the filling shaft cover channel with fresh air supply is missing, but that

 Carbonization gas-air mixture is fed back into the ember bed as a downflow through the outer duct with fresh air supply,

 Fig. 3 shows a chute with a

 Filling chute cover duct, carbonization gas recirculation with fresh air supply with injector effect,

 Fig. 4 shows a Kachelofe.n, in which the inventive

 Device with injector effect is installed and

5 shows a detail from the filling shaft cover area of the furnace according to FIG. 1. Corresponding parts in the various figures are identified by the same reference numerals.

The filling shaft combustion furnace shown in FIG. 1 comprises a filling shaft 1. The filling shaft 1 serves to hold the various solid fuels such as wood, coal, coke, etc.

 The filling shaft 1 is separated by a side wall 2 from a burnout chamber 3 connected downstream of the filling shaft 1. In the side wall 2 there is an oil or gas combustion chamber 4 which opens into the combustion outlet 5. The Brennraυm 4 serves as a combustion chamber for the. Oil or gas combustion, whereby the solid fuels can be ignited at the combustion outlet 5 by means of an oil burner or gas burner. The combustion exit 5 is limited at the top by a canopy designed as a glow element 6 and formed from one or more closed plates, by which the combustion exit 5 is covered with respect to the filling chute 1. The operation of the incandescent body 6 is explained in more detail below.

The lower limit of the combustion outlet 5 is formed by a gas mixing head 7 which is adjacent to a ash removal grate 9 lying above an ash drawer 8. A channel 14 is located between a side wall 12 of the filling shaft 1 and the furnace wall 13.

 In the gas mixing head 7, the amount of air and flue gas passed through the duct 14 is passed through holes and slots to the ember bed,

at the combustion outlet 5 of the solid fuels. The ash removal grate 9 is connected to a pull rod 10 with which the

The embers are shaken and the combustion residues can be discharged into the ash drawer 8.

At the other end of the ash removal grate 9 borders a so-called rush grate 11 which continues the second side wall 12 of the filling shaft 1 opposite the side wall 2 downwards. The the lower end of the channel 14 is connected to the filling shaft 1 via the sliding grate 11, above the ash removal grate 9. The channel 14 is connected at its upper end via a passage 15 between the underside of the filling manhole cover 16 and the side wall 12, the passage 15 serving as a pressure compensation opening. Then through the passage 15

Smoldering gases forming above the fuel located in the filling shaft 1 mixed with air in the channel 14 and returned to the filling shaft 1 via this. The air is fed through a fresh air flap 17 in the ceiling area of the furnace in a controllable manner via a fresh air supply duct 18 through a filler duct cover duct 19. 5 shows an enlarged section of the ceiling area of the filling shaft 1. Through the fresh air flap 17 with adjustable

 Setting to limit the fresh air supply, the fresh air flows through the fresh air supply duct 18, deflected upward by a deflection wall 20, to the filler manhole cover 16; Below the filler manhole cover 16 is the filler manhole cover duct 19 running along the filler manhole cover 16. As a result of the through the deflection wall 20 and one forming the upper end of the side wall 2 to the filler manhole cover duct 19

 leading baffle 21 narrowed flow path of the fresh air supplied through the fresh air flap 17, the flow speed of the air flow is increased and tears with the injector effect in the filling shaft 1 through the fuel

 carbonization gases ascending with them and through the filling manhole cover channel 19 and feeds the carbonization gas / air mixture to the channel 14, in which the carbonization gas / air mixture as falling flow together with the carbonization gases from the filling tube 1 coming into the channel 14 via the pressure-equalizing passage 15 passed downwards and is fed through the sliding grate 11 to the filling shaft 1 for combustion.

The incandescent body 6, which, as already mentioned above, covers the combustion passage 5, is an essential part of the

Filling shaft combustion furnace according to FIG. 1.

The incandescent body 6 is through the through the firing 5

flowing hot gases made to glow. As a result of the roofing of the combustion outlet 5, the incandescent body 6 prevents the cool carbonization gases which form at the combustion passage 5 from entering the burnout chamber 3. The temperature of the incandescent body 6 excites the fuel materials lying thereon to form hot carbonization gases.

 A pre-heat zone is thus formed above the combustion outlet 5, in which the carbonization gases preferably rise along the side wall 2, the so-called combustion output wall 2, so that the carbonization gas recirculation is specifically promoted and improved. In addition, the chimney draft is better fed to the ember bed through the roofing of the combustion exit 5, with the result that a uniform burn-off from the sliding grate 11 to the gas mixing head 7 is ensured, since a small amount of residual air is supplied on

 Gas mixing head 7 or on the deashing grate 9 enables clean combustion.

First of all, however, it should be emphasized that the heated carbonization gases enable an improved upward flow direction and thus, in turn, an improved carbonization gas return through the filler shaft cover channel 19 and the outer channel 14.

That is, the above-described construction of the filling shaft furnace achieves a specific flow through which the carbonization gases formed in the area of the combustion outlet are drawn upward essentially along the combustion outlet wall 2 and as a result of the injector action and the effect of the false flow in the channel 14 through the channel .14 by the

Grate 11 can be returned to the bed in the filling shaft.

Along the carbonization gas recirculation, in particular the carbonization gases formed in the combustion exit area, in a more targeted manner along the top of the combustion exit wall 2 into the filling chamber cover area and from there finally through the channels 14 back into the filling chamber 1, is the

 Firing outlet wall 2 a guide wall 22 is arranged, which is pivotable about the joint 22a. An upwardly directed flow channel 23 is formed by the firing outlet wall 2 and the guide wall 22, which flows into the filler shaft cover area

 opens, so that the smoldering gases rising in it are carried away by the fresh air flow, and are even better passed through the fill-duct cover duct 19 to the outer duct 14.

In other words, this means that the carbonization gases are drawn off in a targeted manner from the area above the combustion outlet 5, so that the negative effects of cool carbonization gases on the combustion process can no longer occur.

Since the parts of the

 Incinerator are of no importance in connection with the present invention, it will not be explained in detail.

In the room stove shown in FIG. 2, the fresh air supply explained in connection with the filling shaft combustion furnace according to FIG. 1, provided in the cover area of the filling chamber 1, and the filling shaft cover duct 19 connected therewith are missing. Instead of the incandescent body 6 in FIG. 1, the combustion passage wall is set 2 in a cast or stone block 6a, which covers the combustion exit 5.

Through the flow channel 23 between the Brenna _^ output wall 2 and the guide wall 22, the hot carbonization gases rise and become above the filling material by the air supply in the case of 24, the downward flow of the carbonization gas / air mixture coming from the filling chamber 1, greatly accelerated with the injector effect, is also torn down in the outer channel 14 and returned to the ember bed.

Instead of the gas mixing head 7, a Durchbrandrost 7a is installed here, through which necessary residual air is supplied to the combustion.

In the incinerator shown in Fig. 3, the air supply in the outer channel 14 is dispensed with. In contrast, however, fresh air is supplied through the fresh air flap 17 in the filling shaft cover area under the action of an injector, and the hot carbonization gas rising up along the side wall 2 is fed along the cover area of the full shaft 1 to the outer channel 14, through which it is returned to the ember bed as falling current.

 In this training example, there is no roofing over the burning outlet 5. Nevertheless, it is possible to draw the smoldering gases along the side wall 2 upward through the fresh air supply with injector effect in the lid area and to return them to the ember bed as falling flow.

A further embodiment of the device according to the invention is shown in the form of a tiled stove in FIG. 4. Here is missing

again a fresh air flap arranged in the ceiling area, but fresh air with injector effect is introduced through a fresh air flap 25 at the upper end of the outer duct 14.

The suction of the falling flow in the outer channel 14 causes the heated smoldering gases rising along the combustion outlet wall 2 to be entrained and can be fed back into the ember bed in the falling flow of the smoldering gas air mixture. In addition, an injector effect 26 is exerted on the smoldering gases located in the filling chamber 1 on the side 12 opposite the combustion outlet 5 and in its area height with the aid of the sliding grate 11 with the recirculated carbonization gas mixture in order to reinforce the desired flow pattern.

Claims

Patent claims 1. A method for controlling the combustion of solid fuels in a solid fuel combustion system in which the carbonization gases formed in the filling space are returned from the ceiling area of the filling space via at least one channel provided between an outer wall of the filling space and a furnace wall as a downward flow in the lower region of the filling space into the ember bed of the filling space that arise immediately above the firing exit area  Smoldering gases are directed upwards along the inner wall of the filling chamber running between the filling chamber and the combustion chamber and are fed along the ceiling area of the filling chamber in the channels between the outer wall of the filling chamber and the furnace wall as a downward flow to the ember bed. 2. The method of claim 1, d a d u r c h g e k e n n z e i c h n e t that the flow of the Smoldering gases by fresh air supply with injector effect in the ceiling area of the full room and / or by the falling flow of the smoldering gases in the channel or the channels leading to the smoldering gas flow, optionally with additional fresh air supply with injector effect. 3. The method according to claim 1 or 2, d a d u r c h  it is necessary to ensure that pressure equalization is created in the upper filling area. 4. A device for performing the method according to one of claims 1 to 3, characterized in that above the combustion outlet (5) an opening of the combustion outlet against the passage of above the combustion outlet forming carbonization shielding shielding (6) is arranged and / or that in the ceiling area of the  Filling chamber (1) opens a channel (19) (hereinafter called the filling chamber cover duct) which connects the upper region (21) of the filling chamber (1) with the channel (s) (14) running between the filling chamber (1) and the furnace wall (13) and the carbonization gases which form immediately above the combustion outlet (5) are introduced into the downflow of the carbonization gas / air mixture in the channel or channels (14), where appropriate the in the ceiling area of the filling chamber (1)  The filling chamber cover duct (19) provided is connected to a fresh air supply (17, 18) and / or if necessary the duct (s) (14) between the filling chamber (1) and the furnace wall (13) are connected to a fresh air supply (24, 25). 5. The device according to claim 4, d a d u r c h g e k e n n e e c h n e t that the roof (6) is designed as a glow body. 6. The device according to claim 4 or 5, characterized in that the roof (6) is designed as a cast or stone block. 7. Device according to one of claims 4 to 6, d a d u r c h g e k e n n z e i c h n e t that the canopy (6) by one or more closed  Plates is formed. 8. Device according to one of claims 4 to 7,  d a d u r c h g e k e n n z e i c h n e t that the canopy (6) on the combustion exit wall (2) is arranged obliquely downwards. 9. Device according to one of claims 4 to 8, d a d u r c h g e k e n n z e i c h n e t that the fresh air supply located in the ceiling area of the filling room  Filling chamber cover channel (19) with injector effect. 10. Device according to one of claims 4 to 9, d a d u r c h g e k e n n z e i c h n e t that the fresh air supply in the channel or channels (14) between the filling chamber (1) and furnace wall (13) with injector effect. 11. Device according to one of the preceding claims,  d a d u r c h g e k e n n z e i c h n e t that im  Filling chamber (1) is arranged at a selectable distance within and along the firing outlet wall (2), a guide wall (22) which begins approximately above the firing outlet opening (5) and approximately to below the filling chamber cover channel (19) is sufficient and forms a channel (23) with the combustion outlet wall (2) for the carbonization gases that form in the combustion outlet area and flow upwards. 12. The device according to claim 11, that the guide wall (22) is designed as a folding wall which can be pivoted about a joint (22a) provided at its lower end. 13. Device according to one of the preceding claims,  Because of this, the combustion chamber (4) opens into the combustion outlet (5) in a filling shaft combustion furnace that is equipped for multivalent combustion with gas or oil and solid fuels.