AT518525B1 - Plant and method for burning organic material - Google Patents

Abstract

The invention relates to a new plant for the combustion of organic matter (10) with increased mineral fractions such as animal excrement with combustion device (1) with main (4) and subsequent post-combustion chamber (5) with supply of primary and secondary air (3), by a grate (2) transporting the firing material (10) and the hot combustion gases (50) connected to the post-combustion chamber (5) in and through a heat exchange unit (6) whose two vertical tube heat exchangers ( 60, 60 ') either alternately each DC or countercurrent mode or in part-load mode are operable.

Description

Description: The present invention relates to a novel, highly effective plant for the combustion of organic matter with increased mineral, in particular dust or ash fractions, in particular of animal excrements, such as chicken manure, with a - so acted upon, obliquely moved Transport grate, in particular stair grate, comprising combustion device or furnace with main and subsequent post-combustion chamber, gradual supply of primary and secondary air, through the said grate and to the post-combustion chamber connected leadership of the hot combustion gases in and by a heat or heat recovery system.

It is already a large number of incinerators for a variety of substances, especially waste and the like. Organic nature has become known and also gone into operation, the spectrum of, in particular from the point of view of environmental protection, the best of a combustion at the highest possible temperature practically unmanageable ranging from kitchen and food waste over animal carcasses to excrements.

The previously known incinerators have repeatedly exhibited severe deficiencies, resulting from the toxicity of the discharged from them to the environment and difficult to eliminate and manageable harmful exhaust gases to Verteeren and / or even slow growth of combustion chambers and in particular the combustion gas -Ferleitungsrohre, valves, downstream heat exchangers and the like. Has led.

In the current market, there are only conventional automatic biomass combustion plants in which the volume of the combustion chamber has been increased in order to burn such types of difficult-to-burn substances with higher efficiency. However, these systems do not take into account the often high ash content of biomass occurring in the combustion chamber and in subsequent heat exchangers.

[0005] The step grate combustion is published as the standard method in these types of fuels. Due to the even distribution of the primary air, as well as the supply of secondary air, very high firing temperatures, resulting in complete combustion.

The use of these plant components in conjunction with the combustion of animal excrement, especially of chicken manure leads to a particularly high particulate matter and / or ash - share ultimately in the main exhaust stream, and to an absolutely unacceptable increase in thermal NOx -content.

In order to reduce the NOx content in the combustion exhaust gas, the volume or air to be used for combustion should be reduced per se, but even then the unpleasant and difficult to control dust problem remains.

Furthermore, there is the problem that, for example, the heavy dust particles are poorly removed from the afterburning chamber and accordingly it is increasingly polluted.

This leads to a narrowing of the cross section of the afterburner and thus to a continuously increasing loss of power of the combustion device as a whole.

Furthermore, the downstream of the new combustion device, integral with her heat exchanger device is much more contaminated, this has the consequence that the overall efficiency is reduced and it is constantly a mechanical cleaning necessary.

In addition, the heat exchangers are usually flowed through only in the DC principle, but this means that the deposits appear in the Rohrapparat of the heat exchanger reinforced.

The partial load operating mode previously represented another obstacle, which is due to the formation of condensate in the heat exchanger.

The condensate consists primarily of Ρ205 and SOx, these two chemicals have a damaging effect, as is known, at least on the boiler body. Therefore, the systems had to be operated constantly in full load operation.

One of the largest current problems encountered in the combustion of animal excrement, especially chicken manure, is the dust emissions from such plants. Due to the high ash or dust deposits, there are constrictions in the flue gas ducts and these constrictions then reduce the efficiency of the plants.

The invention has set itself the goal of creating an incinerator for organic matter and in particular for today in large and in many cases difficult-to-control amounts resulting animal excrement, in which the above - by no means in detail or only approximately vollzählig - said organic Substances appear as possible without the residues and other adverse circumstances described above.

The present invention is a newly designed, as mentioned above, plant for residue-free combustion of organic matter, in particular animal excreta come to the fore, which is characterized in that - in a spatially oblique above widening main combustion chamber of a combustion furnace in or through the on the transport grate in the moving device promoted organic fuel over a plurality of, in particular at least three in the same direction of movement of the same successively arranged air supply openings, nozzles or the like. Primary combustion air, each with in Movement direction of decreasing intensity and on the same following in the direction of movement, at least two further, successively arranged such openings, nozzles or the like. Secondary combustion air can be fed.

- That the fuel ash and / or dusts formed in this case with leading, hot combustion gases via a - more inclined than the transport grate upwards, the main combustion chamber upwardly bounding partition or the like. Released Passage zone in the direction of movement in the substantially inverted or inverse direction into and through the combustion chamber, which is also limited spatially, in particular downward, to the main combustion chamber, extending in the current combustion gas movement direction, [0020] in which the incombustible material components, in particular combustible ash and / or dusts, accumulate in the region of their trained therein, gutter-like, deepest point, and, preferably by means of there befindlicher cooled discharge screw, continuously discharged from there are, and [0021] that s Finally, the hot combustion gases substantially freed from combustible ash and / or dusts are passed through a combustion gas outlet arranged in the ceiling of the afterburning chamber with combustion gas exhaust pipe thereafter into and through a two-vertical heat recovery device. Heat exchangers can be transferred or guided.

By the targeted, in the direction of travel of the most complete combustion supplied organic material on the transport grate with simultaneous supply of combustion air through the transport grate through selectively progressively decreasing flow rates of primary and secondary air per unit time can be, as is Surprisingly, it has been shown to achieve such complete combustion that it is no longer, as in the combustion and heat recovery plant described above, with difficult-to-control, ultimately still organic, high-molecular, often highly viscous, furnace travel in many cases ultimately difficult obstructive residues and the like. Comes.

The supplied in at least three zones than at least three nozzle devices

Primary air is needed to efficiently burn various different degradable organic materials. Depending on the density and composition of the material to be burned as completely as possible, a large amount of air is blown in or less by means of the first primary air supply nozzle. Thereafter, the combustion air supply to the subsequent two further two primary zones.

The at least two times secondary air supply is metered depending on the material to be burned in order to achieve a significant reduction of the NOx and the dust content in the combustion gas.

In the primary combustion chamber organic substances are burned with an ash content of up to 25%, therefore, after the zone of the secondary air supply, the extension of the secondary combustion chamber, which has the consequence that targeted as complete as possible ash and dust deposition can take place.

According to previously known prior art, such ash deposition is not specifically carried out in the afterburner and therefore effective cleaning of this chamber has only been possible to a limited extent.

Directly connected to the highly effective combustion device according to the invention and integral with it and for the achievement of the object of the present invention, the heat and heat recovery means, by means of which - tunable to the respective amount of this unit per unit time continuous organic material - the combustion gases inherent heat or heat can be used for a variety of purposes.

The heat exchanger means together with the novel combustion device is a fundamental part of the invention.

The coming of the combustion device from the hot combustion gases to be flowed first heat exchanger is equipped only about half with heat exchange tubes and the other "empty" half is only traversed in the case of the DC mode in the second heat exchanger of the combustion gases.

The reason for this new type of construction is that it allows the partial load mode to be achieved. This design prevents the flue gas temperature in the first heat exchanger from falling below the dew point in partial load operation mode.

Therefore, the first heat exchanger can be performed with conventional boiler steel, at the same time a contamination of the heat exchanger is largely prevented.

Another reason of this special arrangement is that the first heat exchanger can always be flowed through in the same direction, since as a result of the high temperatures prevailing there, the ash and dust deposition tendency is very low.

The second heat exchanger operates only for the full load operating mode. As a result of the relatively low combustion gas temperature, the second heat exchanger is not flowed through in the partial load operation in order to prevent condensation from the outset right there.

If only, as before, a heat exchanger are flowed through in each case in the DC and countercurrent mode, a partial load operation of the system without difficult to control disturbances would not be possible.

The quantity-specific operating within the scope of the incinerator according to the invention for (recovering) the heat generated in the combustion device with two heat exchanger units is characterized in that [0036] that the two upper and the two lower conical, with ash, and / or dust discharge valves (empty) spaces of each of the two vertical heat exchanger units of the heat recovery device are connected to each other via combustion gas guide tubes with shut-off valves built therein, that the combustion gas exhaust pipe from the afterburner chamber of the combustion device in the upper (empty) room of the main combustion heat exchange part to be flowed through from the hot combustion gases vertically downwards, equipped with heat exchange tubes and separated from a heat exchange tube free passage part thereof by a vertical partition wall, and [003 9] - that the upper and the lower conical space of the second heat exchanger unit in each case via two outgoing from the same, each equipped with a built-in flap valve pipe branches of a substantially substantially C-shaped exhaust gas exhaust pipe with exhaust port to an exhaust aftertreatment and cleaning plant or the like are connected to each other.

Depending on the resulting, the incinerator per unit of time supplied quantity and quality of organic material and its quality can be the above, provided in the present invention, in this respect extremely flexible, new heat (re) ge-winning device, which to the previously described combustion device is connected, in three main variants or main modes, namely operate in the DC, countercurrent and part-load mode.

In this sense, the driving of the heat recovery device, ie the method for heat recovery, according to variant 1, DC mode, characterized in that with open barrier flaps in the upper combustion gas supply connec tion tube and in the lower tube branch of Abgasabführungsrohrs and with closed barrier flaps in the lower Combustion gas guide connecting pipe and in the upper pipe branch of the exhaust gas exhaust pipe, the exhaust gas from the afterburner chamber of the combustion device exhaust gas through the upper (empty) space of the first heat exchanger unit and first down through the main heat exchange tube part, then up through its passage part, and then down through the second heat exchanger unit and are guided or discharged via the lower pipe branch of the exhaust gas removal pipe.

The variant 2, countercurrent mode, the heat recovery method according to the invention is characterized in that with closed shut-off flaps in the upper Ver-combustion gas guide connecting pipe and in the lower pipe branch of the exhaust-removal pipe and open barrier flaps in the lower combustion gas guide connecting pipe and in the upper pipe branch the exhaust gas exhaust pipe, the exhaust gas from the post combustion chamber of the combustion device exhaust gases through the upper (empty) space of the first heat exchanger unit and first down through its main heat exchange tube part, then up through the second heat exchanger unit and finally over the upper pipe branch of the exhaust gas exhaust pipe or be discharged.

Finally, according to process variant 3, part load mode, provided that with closed barrier flaps in the upper combustion gas duct connecting pipe and the upper tube branch of the exhaust-removal pipe and at the same time opened shut-off valves in the lower combustion gas guide connecting pipe and in the lower pipe branch of the exhaust gas exhaust pipe the combustion gases exhausted from the afterburner chamber of the combustor through the upper empty chamber of the first heat exchanger unit and first downwardly only through the main heat exchange tube member, then directly through the lower conical void of the first heat exchanger unit, then through the lower combustion gas supply connection tube and finally through the lower combustion chamber lower (empty) space of the second heat exchanger unit and lower pipe branch of the exhaust gas removal pipe out or be discharged.

The heat exchanger means together with the novel combustion device is a fundamental part of the invention.

The new heat exchanger device according to the invention thus formed with two vertically positioned heat exchangers, and not, as usual, usually with only one horizontal.

The second heat exchanger can according to the DC and the countercurrent mode, each based on the always constant direction of the downward guidance of the hot combustion gases in the first heat exchanger, operated.

As a result of the ultimately still present, albeit small dust content in the hot, coming from the incinerator combustion gases can form difficult to remove deposits in the second heat exchanger. Therefore, it is particularly advantageous that at regular time intervals, the second heat exchanger is to flow in the opposite direction to remove initial residual dust deposits.

These deposits are destroyed on the one hand by the countercurrent, but also by the case brought about changed temperature distribution in the second heat exchanger. Due to the different settings of the flaps in the combustion gas ducts during operation, it is easy to change between the two gas flow-through directions in the second heat exchanger, thus constantly ensuring its significantly simplified cleaning.

Due to the continuous automatic switching between DC and countercurrent so can the deposits mentioned in the second heat exchanger during operation of the new system virtually completely avoided.

The cleaning is thus completely without any mechanical aids and is thus automatically integrated into the normal operation of the new system.

Due to the new way of dividing the heat recovery system integrated in the combustion system according to the invention into two successive heat exchangers and the described possibility of switching the flaps in the combustion gas ducts is achieved that at partial load operation, ie in the partial load mode, only the first heat exchanger of the combustion gases is flowed through.

As a result, the exhaust gas temperature in the heat exchanger device remains at substantially the same level as in full load mode and any condensation is prevented. In this way, in a combustion plant with one and the same novel heat recovery device, a true partial load operation without adverse consequences, for example, for the environment and without complicated cleaning requirements.

Thus, the emission values at Berieb in the partial load mode remain virtually the same as in continuous operation in full load mode, which could not be achieved so far.

1 shows essentially a sectional view of the new combustion device of the novel incinerator according to the invention, and FIGS. 2, 3 and 4 show the same in each case. [0054] FIG Fig. 2 shows the individual positions of the blocking elements, ie flaps in the combustion gas ducts between the two heat exchanger units and that in the DC mode, Fig. 3 4 shows those positions of the flaps in the combustion gas ducts between the two heat exchanger units in the partial load mode.

Fig. 1 shows a substantially box-shaped combustion furnace 1 with two combustion chambers 4, 5 for as desired according to the invention, the most effective combustion of chicken manure 10, which is known for high dust accumulation.

In the interior of this furnace 1 there is arranged an obliquely ascending stair grate 2, which carries material in the direction tr, and which transports the chicken manure 10 applied to it slowly in the combustion chamber 4 in the direction tr upwards. From the stair grate 2 from below the same brought here, here three air supply nozzle units 31, 32, 33 primary combustion air 3 is blown through the grate 2 and by the same moving, burning chicken manure 10 and indeed in from air supply nozzles 31 to air supply nozzles 33 descending cubic meter Quantities per hour.

By in the direction of rust movement tr the nozzles 31-33 following two nozzles 3T, 32 'is secondary combustion air 3' through the grate 2 and thereon, ultimately only very small amounts of combustible substance, so virtually no organic components more containing, inorganic chicken manure ash 10 injected.

The liberated from the chicken manure 10 combustion gases 50 flow with entrainment of non-combustible ash particles 10 'in the expanding primary combustion chamber 4 between the obliquely upwardly rising transport grate 2 and the more oblique than the transport grate 2 obliquely upwards aligned combustion chamber partition wall 45 in the direction + TR upwards and pass through the opening 54 left free from the aforementioned partition wall 45 in the obliquely downwardly expanding secondary combustion chamber 5 with a formed by the combustion chamber partition wall 45 obliquely downward type Soil, in which space 5, the inorganic chicken manure ash particles continue to move downward in an essentially negative direction -RT.

In the approximately groove-like space 51 formed by the vertical wall of the combustion chamber and the oblique partition wall 45, the ash 10 'settles out for the most part and can therefrom e.g. be transported by means of the screw conveyor 55 to the outside.

The hot combustion gases 50 finally leave the secondary combustion chamber 5 through the gas discharge opening 101 of the combustion device 1 and enter the heat recovery device 6, which is not detailed in this figure.

Comprises an integral part of the new combustion plant 100 forming heat (recovery) recovery device 6, each connected via an upper and a lower combustion gas connecting pipe 7, 7 'interconnected first and second heat exchanger units 60, 60 ', wherein in the upper space 61 of the first heat exchanger 60 via the connected to the combustion device 1 oblique gas guide tube 75, the hot combustion gases 50 pass.

From there, they flow down through the heat exchange tubes 62, where they release their heat to a heating medium or the like.

Then they flow through the lower conical (empty) space 63 with Staubaustragseinrichtung 64 and flow with the flap closed 72 in the lower connecting pipe 7 'in and through the empty passage part 65 of the first heat exchanger 60 upwards and continue to open when the barrier flap 71 through the upper connecting pipe 7 in the upper (empty) space 61 'of the second heat exchanger 60'. In the passage part 65 further small ash particles settle and also get into the lower conical (empty) space 63 with the discharge 64th

From there, the already partly-cooled combustion gases flow through the heat exchange tube 62 of the second heat exchanger 60 'downwards and there emit their residual heat, then pass through the lower conical (empty) space 63' with residual dust discharge 64 'in the lower branch 82 of the C-tube 8, in which the local blocking flap 74 is opened while the blocking flap 73 is closed in the upper branch 81 of the C-tube 8, through the gas outlet opening 83 from the heat exchanger device 6 of the new incinerator 100 outside, for example, a Gasnachreinigungsanlage or the like.

The above-described guidance of the hot combustion gases 50 within the heat exchangers 60, 60 'corresponds to the "DC mode".

Fig. 3 shows, with completely the same structure of the heat recovery device 6 and otherwise the same reference numerals, the driving style when using the "countercurrent mode". Again, the hot combustion gases 50 flowing upwards in the inclined tube 75 pass into the upper (empty) space 61 of the heat exchanger 60 and through its replacement tubes 62 downwardly into the lower connecting tube 7 'with the now open blocking flap 72.

However, the combustion gases do not now flow through the passage part 65 of the first heat exchanger 60, since the barrier flap 71 in the upper connecting pipe 7 to the second heat exchanger 60 'is closed, but they flow from the lower conical (empty) space of the first heat exchanger 60 with the trapdoor open 72 equal in the lower conical (empty) space 63 'of the second heat exchanger 60' and - since the locking flap 74 is closed in the lower branch 82 of the C-tube - now from there upwards through the heat exchange tubes 62 '- so not downwards, like in the "DC mode", but in the opposite direction here-give their residual heat to a heating medium or the like. From and then flow through the upper (empty) space of the second heat exchanger 60 and finally opened in the upper limb of the C-tube 8 through the opening 83 to the outside, for example in a gas scrubber.

Due solely to the "opposite" flow and thereby significantly changed temperature conditions in the combustion gases any dust deposits that would otherwise be removed only mechanically, are removed. Both the "DC mode" and the "countercurrent mode" mode of operation shown in FIG. 2 are alternately performed, and in this way, dust and ash settlements that are difficult to remove mechanically during full load operation of the heat recovery device are often impossible simple periodic change of the flow direction of the combustion gases 50 in the second heat exchanger 60 ', which reacts much more sensitive due to the low temperature of the gases in this regard, prevent.

Finally, FIG. 4 shows - with an overall consistent design and otherwise constant reference numerals - the driving style when using, for example, less well-burning organic materials or those with lower organic content or, if smaller amounts of combustible matter is used, so the driving style in "partial load mode".

With otherwise constant reference numerals is in part-load operation by closing the locking flaps 71 and 73 in the upper connecting pipe 7 and in the upper branch of the C-tube 8, with simultaneous opening of the two locking flaps 72 and 74 in the lower connecting pipe 7 'and in the lower C Pipe branch 82 the combustion gases 50 leaving the first heat exchanger 60 at the bottom no longer flow through the second heat exchanger 60 'or through its heat exchange tubes 62' but flow through the lower branch 82 of the C pipe 8 and exit the heat exchanger device 6 through the gas outlet port 83.

Claims (5)

claims 1. plant (100) for the combustion of organic matter (10) with increased mineral, especially dust or ash fractions, in particular of animal excrements, such as chicken manure, with a thus acted upon, obliquely moving transport grate (2) , in particular staircase, having combustion device (1) with main (4) and subsequent post-combustion chamber (5) with gradual supply of primary and secondary air (3), by said grate (2) and to the post-combustion chamber ( 5) connected guide the hot combustion gases (50) in a heat or heat recovery device (6), characterized in that - in a kiln (1) in a spatially obliquely upwardly widening main combustion chamber (4) of the combustion device in or through on the transport grate (2) in the direction of movement (tr) funded organic kiln (10) over a plurality of, in particular at least three, in motion Direction (tr) of the same successively arranged air supply openings, nozzles (31, 32, 33) or the like. Primary combustion air (3) each with in the direction of movement (tr) of the transport grate (2) decreasing intensity and over in the direction of movement (tr) the same following, at least two further, such successively arranged such openings, nozzles (31 ', 32') or the like. Secondary combustion air (3 ') can be fed. - That the fuel ash and / or dusts (10 ') formed in this way with leading, hot combustion gases (50) via a - from a more inclined than the transport grate (2) upwards, the main combustion chamber (4 ) upwardly delimiting dividing wall (45) or the like. Released - passage zone (54) in the previous direction of movement (+ TR) substantially reversed or inverse direction (-TR) in and through the said partition wall (45) down to the main combustion chamber (4) towards limited, in current combustion gas movement direction (-TR) also spatially expanding afterburning chamber (5) are conductive, - in which in the region of the groove-like deepest point (51), the non-combustible material components, in particular kiln -Asche and / or dusts (10 '), accumulate, and, preferably by means located there cooled Austragsschnecke (55), are continuously dischargeable from there, and - that schl The hot combustion gases (50), which are largely freed from combustible ash and / or dusts (10 '), are provided by a gas outlet (101) arranged in the ceiling of the afterburning chamber (5) of the kiln (1) and having combustion gas thereon -Abführungsrohr (75) in and by a heat or heat recovery system (6) with two vertical heat exchangers (60, 60 ') can be transferred or feasible bar. 2. Plant (100) according to claim 1, characterized in that - the two upper (61, 6T) and the two lower, conical, with ash, and / or Staubaustragsventilen (64, 64 ') equipped (empty) spaces ( 63, 63 ') of each of the two vertical heat exchangers (60, 60') of the heat or heat recovery system (6) of the incinerator (100) according to claim 1 respectively via combustion gas guide tubes (7, 7 ') with built-in barrier valves (71, 72) are interconnected, - that the combustion gas discharge pipe (56) from the afterburner chamber (5) of the kiln in the upper void (61) of the from the hot combustion gases (50) vertically downwardly to be flown equipped with heat exchange tubes, by means of vertical partition (66) from a heat exchange tube-free passage part (65) of the same separate main heat exchange part (62) thereof opens, and - that the upper and the lower conical space (61 ', 63') of the second heat exchanger (60 ') in each case via two pipe branches (81, 82) of a substantially substantially C-shaped exhaust gas removal pipe (8) with exhaust opening (82), each likewise equipped with a blocking flap (73, 74) installed in the same, to an exhaust aftertreatment and -reinigunsanlage or the like are connected to each other. 3. A method for recovering the combustion gases (50) from the afterburner chamber (5) of the kiln (1) inherent thermal energy according to variant 1, DC mode, by means of heat or heat recovery system (6) according to claim 1 or 2, characterized in that - With opened barrier flaps (71, 74) in the upper Verbrennungsgasführungs- connecting tube (7) and in the lower tube branch (82) of the Abgasabführungsrohrs (8) and - with closed barrier flaps (72, 73) in the lower combustion gas Ver-Ver connection tube (7) and in the upper tube branch (81) of the exhaust gas removal tube (8), the combustion gases (50) withdrawn from the afterburner chamber (5) through the upper headspace (61) of the first heat exchanger and first downwardly through its main heat exchange tube member (62), then upwardly through the passage part (65), and then down through the second heat exchanger (60 ') and through the lower pipe branch (82) of the exhaust gas discharge pipe (8) out or is dissipated. 4. A method for recovering the combustion gases (50) from the afterburner chamber (5) inherent heat energy according to variant 2, countercurrent mode, by means of the heat recovery system (6) according to claim 1 or 2, characterized in that - with closed barrier flaps (71, 74) in the upper combustion gas guide connecting pipe (7) and in the lower pipe branch (82) of the exhaust gas removal pipe (8) and - in open flaps (72, 73) in the lower combustion gas guide connecting pipe (7) and in the upper pipe branch (81) of Exhaust evacuation pipe (8) from the post combustion chamber (5) of the incinerator (1) deducting combustion gases (50) through the upper void (61) of the first heat exchanger and first down through its main heat exchange tube part (62), then through the second Heat exchanger (61) upwards over the upper pipe branch (82) of the exhaust gas discharge pipe (8) are guided or removed. 5. A method for recovering the heat energy inherent in the combustion gases from the afterburner chamber of the kiln according to variant 3, part load mode, by means of the heat recovery system (6) according to claim 1 or 2, characterized in that - with closed barrier flaps (71, 73) in the upper combustion gas supply Connection pipe (7) and in the upper tube branch (81) of the exhaust gas discharge pipe (8) and - simultaneously with opened shut-off flaps (72, 73) in the lower combustion gas supply connection pipe (7) and in the lower pipe branch (82) of the exhaust gas discharge pipe (8) the combustion gases (50) withdrawn from the afterburning chamber (5) of the incinerator (1) through the upper empty chamber (61) of the first heat exchanger (60) and first downwards only through its main heat exchange tube part (62), then directly through the lower conical void (63) of the first heat exchanger (60), then through the lower combustion gas guide connecting pipe (7 ') and closing Lich through the lower pipe branch (82) of the exhaust gas discharge tube (8) are guided and discharged. 4 sheets of drawings