FI98855C - Incinerator for wood waste - Google Patents

Description

93855

The present invention relates to an apparatus which improves the combustion process and facilitates the operation of a low-feed wood waste incinerator with a front housing and an afterburner.

5 In Finland and Sweden, there are several dozen plants, mainly suitable for the incineration of moist sawdust (bark, wood chips, sawdust, etc.), where the fuel is discharged from the bottom upwards by a counter-threaded sternary screw through a discharge cone first over the stair treads and then collapses .

10 Since the 1960s, the The following companies have manufactured and filed patent applications for combustion equipment: Aktiebolaget Götaverken, Götaverken Ängteknik Ab, Berg & Starck and Änga & Värme from Sweden and Sermet Oy from Finland since 1979. (Patent publications: FI 40 022, SE 109861, patents 52770) and 65770.

In addition, several individuals representing the users of incinerators have filed patent-15 applications for inventions which have sought to counteract the disadvantages of the above types of plants. Wood waste incineration plants built back in the 1980s with the above-mentioned equipment technology contain at least the following disadvantages: 1) The amount of fuel in the grate does not remain constant, but depending on the heat load, there is either too much or too little fuel.

20 2) Blockages easily occur in the fuel supply to the junction of the transfer screw and the stub screw.

3) The lifting part of the stubble screw causes fuel to be compressed and condensed in the screw chute due to the counter-thread.

98855 2 4) The stem screw with its counter-threads, which raises the fuel into the discharge cone, causes one-sided fuel discharge to the grate surfaces.

5) The air gaps between the separate level and step gratings tend to become clogged as the ash and sand “sinter” at high temperatures.

5 6) Combustible gases enter the first combustion chamber of the afterburner from an opening in the rear wall of the front housing, which causes more intense combustion in the fuel layer at the rear of the front housing.

7) Not all gases generated by the incineration of wood waste are ignited and burn to the end. Carbon particles moving from the fuel layer of the front housing move in too 10 “laminars” in a gas stream through the masonry nest structures to the convection boiler, where their combustion is finally interrupted due to too low a combustion temperature.

8) Partially non-combustible fuel falls from the air gap between the separate stair and planar gratings and the thermal energy contained in it remains unused.

9) After the convection boiler, the flue gas temperature cannot be reduced to substantially below +150 ° C due to the “corrosion risk” at the rear of the boiler.

10) The flue gas blower and combustion air blowers, when started, cause pressure fluctuations in the front housing, which allow carbon particles to move from the surface of the 20 fuel layers.

11) The air space under the grate, cast from a concrete base, is leaking, so the conduction of combustion air to the grate is uncontrolled.

>! 98855 3 12) The massive afterburner is designed for wet wood waste fuel. If the fuel is drier than normal, it should be possible to shorten the combustion gas circulation.

13) The power control of the incinerator is not easily controllable.

The structural details by which the above-mentioned drawbacks can be eliminated are explained in more detail in the claims of this patent application.

The invention will now be examined in detail with the aid of the accompanying drawings, which comprise a total of 11 sheets. Figures 9 and 10 show a section, which is shown in more detail in the other figures.

Figure 1: Surface switch to be mounted on the wall of the front housing. The upper figure is a section in the side direction-10 and the lower figure is a section seen from above.

Figure 2: The so-called wood waste incineration plant according to the invention. LAYOUT drawing.Tan diggers (9) on each side of the front housing (32) and only one screw (10), which acts as both a transfer and stubble screw.

Figure 3: Section in the direction of the stoker screw (10) in the middle of the front housing (32). Wider, 15 separate stubble screw gutters (14) with hinge joints and discharge cone cut na.

Figure 4: Section of the stubble screw and discharge cone.

Figure 5: Sections on the left of the top end brackets (16), discharge cone (13) and curved flat steel (19). In the middle, the bracket (16) for the connection of the step gratings and 20 level gratings and the middle one is cut from the annular U-98855 4 profiles (17). On the right, the outer support ring (16) of the level gratings with its support plates and the outer U-profile ring.

Figure 6: Section of the front housing base at the stator screw. The figure shows the secondary air blowing duct (22, total 2) and the primary air duct (27, total 4 5).

Figure 7: The upper figure is a longitudinal section from the center of the afterburner and the lower figure is seen from above at the same point. The figure shows the principle of installation of the afterburner elements and the extrusion of carbon-containing ash through the discharge map (43) into the afterburner.

10 Figure 8: Section from the center of the front housing in the transverse direction. The figure shows the structure of the vibrating hopper (30) below the step gratings and the structure of the vibrating plates (36) below the planar gratings.

Figure 9: Section (B - B) from the center of the entire combustion and boiler system in the longitudinal direction. The picture shows the combustion and ash equipment.

15 Figure 10: Section (A - A) seen from above. The picture shows the walls of the masonry structures and the equipment inside them.

Figure 11: Section of the corner points of the front housing (4 pcs.), Where the water-cooled stand structure of the front housing with its bushing principles and the circulating water joint are described in more detail.

Fig. 10 shows the combustion plant as a whole seen from above in the section plane A-A and Fig. 9 seen from the side in the section plane B-B. Em. the two figures outline the location of the inventive details of the apparatus and 98855 5 a more detailed representation of the structural details is shown in the other figures using the same numbering as in the claims.

1) The first claim of the apparatus which is the subject of the patent application relates to the invention, according to which the surface switch (1) is mounted so that its impeller (2) stops when the fuel extends at a distance of about 10 cm from the outer edge of the planar grate (3). The mounting pipe (4) of the surface switch according to the invention is designed so that the combustion air flows through the pipe and cools the shaft (5) of the surface switch and the impeller. The installation pipe (4) according to the invention is adjustable in the longitudinal direction and is locked in the desired position with locking screws (6). The surface switch 10 is resiliently mounted on the mounting flange (7) by means of springs (8). The surface switch stops the operation of the rod unloaders in a previously known manner and the clock switch starts a new fuel supply cycle within the set time.

2) The second claim of the patented device relates to the invention, according to which the fuel is fed by rod unloaders (9) in a controlled manner directly to the counter-threaded stator screw (10) on both sides of the front housing (32), without the need for separate transfer screws. The supply of fuel to the front housing is then simple and reliable, and blockages cannot occur when the transfer power of the stem screw helix (11) increases in the discharge direction.

3) The third claim of the claimed apparatus relates to the invention 20, according to which each helix (11) of the stubble screw (10) increases in diameter over its final distance, whereby its fuel transfer and lifting power is improved and compaction does not occur as much as with a flat helix. In the same vein, it appears that the screw groove (14) of the stoker screw is wider than the rest of the groove on the part below the step gratings. The separate structure 25 shown in Figure 3 also allows the screw chute to be made of a thicker and more wear-resistant material from the fuel lifting point.

6 98855 4) A fourth claim of the apparatus which is the subject of the patent application relates to the invention (Fig. 4), according to which in current plants the sturgeon screw raises fuel mainly on one side of the core tube (12), positively rising on the discharge cone (13) and collapsing. In the feeding device according to the invention, the discharge cone (13) is arranged in approx.

50 mm eccentrically to the stubble screw chute (14), resulting in a smoother fuel discharge.

5) The fifth claim of the apparatus according to the patent application relates to the invention (Fig. 5), according to which the support frames (16) of the step gratings (15) and planar gratings (3) are moved back and forth by the heat-resistant grease at the base of the annular u-profiles (17). 60 °) with hydraulic cylinders (Fig. 10/18). 8 curved flat steels (19) are welded to the discharge cone (13), which raise the upper ends of the step gratings (15) by approx. 5 mm as the support frame rotates. By the same principle, the curved flat steels (26) welded to the annular outer circumference (20) 15 raise the outer ends of the planar gratings in steps of about 5 mm. Em. The equipment provides height and lateral movement between adjacent grate irons, whereby the ash and sand do not citrate between the grates but fall into the ash space.

The sixth claim of the apparatus which is the subject of the patent application relates to 20 inventions (Fig. 6), according to which combustion air is passed under the planar gratings (3) via two air ducts (22) symmetrically arranged on the base of the front housing. The amount of combustion air can be adjusted by means of two control elements (23) according to the invention, which are made airtight by means of a spring-loaded hinge connection (24). The controls are equipped with a side-swivel inspection hatch (25) with 25 handles (26). Combustion air is passed under the step gratings (15) through four symmetrically arranged air ducts (27). These air ducts are also equipped with control elements having the structure explained above (Fig. 10/23).

Li 98855 7 7) A seventh claim of the apparatus which is the subject of the patent application relates to the invention (Fig. 7), according to which afterburner elements (29) cast from refractory mass according to Fig. 7 are installed in the combustion chamber (28) of the afterburner. Ko. The elements are installed in the 2nd combustion chamber when the afterburner 5 is constructed so that they are loose in the cold housing, but as the temperature rises, the elements expand thermally against the vertical walls. The glowing afterburners ignite the by-passing gases and the carbon particles impinging on the elements burn out with the help of their hot surfaces.

The eighth claim 10 of the apparatus which is the subject of the patent application relates to the invention (Fig. 8), according to which the carbon and ash falling below the step gratings (15) fall onto a vibrating funnel (30) provided with spring brackets. The actual motor vibrator (31, Fig. 9) is outside the front housing and the vibration is transferred to the vibration hopper (30) with a steel profile plate (33). The flexible sheet metal collar (34) seals the joint between the vibrating hopper and the steel plate wall (35). The coal and ash falling below the level-15 grate (3) fall on 2 vibrating plates (36) with spring brackets. The motor vibrator (37) is outside the front housing and the vibration is transmitted to the vibrating plates by a steel profile rod (39) mounted inside the rubber-sealed bushing (38). Em. the hopper and vibratory plates shed the coal and ash into the ash screw chute (40), from which a counter-threaded screw conveyor (41) transfers them to the afterburner combustion chamber 1 (42) through the discharge cone (43) for afterburning. Through the opening in the partition wall (44), a stream of smoke gas transfers and burns coal, which falls as ash between the refractory elements (45) in the 2nd combustion chamber onto the ash screw chute (46). From there, the ash is transferred to the ash tank with a counter-threaded ash screw (47).

9) The ninth claim of the apparatus which is the subject of the patent application relates to the invention (Fig. 9), according to which, after the convection boiler (48), flue gases of approx. + 150 ° C are led through the LTO flue gas cleaner (49) to the chimney 98855 8 approx. + 100 ° C :as. The acid-resistant LTO coil coil (50) is mounted on the replacement hatch (51) on top of the above-mentioned smoke gas cleaner, so it can be lifted off for cleaning without interruption and the closed hatch can be replaced. The LTO coil is connected to the LTO piping with shut-off valves 5 by flange connections (52). The fly ash separated by the LTO flue gas cleaner falls into the gas-tight ash screw chute (40).

10) The tenth claim of the apparatus which is the subject of the patent application relates to the invention, according to which the the power of the wood waste incineration plant is adjusted by adjusting the speed of the flue gas fan (Fig. 2, 53). The flow temperature of the convection boiler (Fig. 2, 48) is kept at its set point (e.g.

+118 ° C) so that according to the pulses of the temperature transmitter (54), the frequency converter (55) adjusts the rotational speed of the flue gas fan (53) so that a constant flow temperature is reached. The combustion air ducts are dimensioned and the air control elements are adjusted so that the amount of combustion air in the front housing fuel is suitable.

11) The eleventh claim of the apparatus claimed relates to the invention (Fig. 11), according to which the base (56) of the front housing (32) is constructed of steel plate and beams so as to form a tight water space (57) circulating freely from the top of the base (58) to the top and from the bottom of the charger back to the bottom of the stand. All bushings 20 entering the base of the front housing are welded to the steel plate walls, whereby they act as binding members of the water space.

All devices entering the base entry points are sealed with rubber or graphite braid seals (59). The afterburner stand (Fig. 7, 60) is built on the same principle as the front housing stand. The free-running piping is connected to another accumulator in the plant (Fig. 2, 61). Em. the accumulators also act as extinguishing water tanks for the stoker-25 screw (10).

98855 9 12) The twelfth claim of the apparatus which is the subject of the patent application relates to the invention (Fig. 9), according to which there are two channels between the afterburner (62) and the convection boiler (48). When switching to drier fuel, the 1st closing element (63) made of refractory mass 5 is lifted from the mouth of the bypass duct (64) to the side, whereby some of the combustion gases enter directly 2.

from the combustion chamber (28) to the convection boiler. When running on low power with low fuel, the 2nd shut-off element (66) can be lifted at the mouth of the channel (65) between the afterburner 3. The combustion chamber and the convection boiler (48), whereby all combustion gases pass through the bypass channel. When oil is burned in a convection boiler, each shut-off element is lifted 10 at the mouth of the ducts.

The thirteenth claim of the apparatus which is the subject of the patent application relates to the invention (Fig. 9), according to which combustion air from the front housing (32) is sucked into the primary air duct (69) and the secondary air duct (70) through the space between the housing masonry walls (67) and the steel plate jacket (68). From the primary air duct, air is further sucked in by the vacuum generated by the flue gas blower through separate ducts (71) located in the middle of the side walls of the front housing into the space below the stairwells via flow ducts (4). From the secondary air duct (70), the secondary air travels on the side walls of the front housing past the air ducts (72) and the control members (23) adjacent to the primary air ducts to a space below the planar gratings. With the help of the combustion air control system, suitable preheating of the combustion air is achieved and, on the other hand, the “waste heat” transferred to the environment by the front housing casing is minimized.

Claims (13)

1. A wood waste incinerator consisting of a front fireplace provided with a stoker screw with feed from below, stack-mounted stair grilles and annularly arranged flat grilles and a multi-chamber post-combustion furnace as well as a shaft (5) with a convection boiler. the fuel supply guiding level guard (1) and a paddle wheel (2) are arranged in a pipe (4), whereby the continuous combustion air flowing through the pipe (4) cools the shaft (5) of the level guard and prevents damage caused by overheating. 10 2. A wood waste incineration plant according to claim 1, characterized in that the plant includes shutters (9), which from the bed of the front fireplace (32) directly trap the fuel in the gutter for a continuously threaded rotary screw (10) provided with opposite threads. transmission power increases in the feed direction. 15 3. A wood waste incinerator according to claim 1 or 2, characterized in that the screws (11) on the stoker screw (10) and the gutter (14) have a larger diameter in the part below the stair grilles than in the other parts of the screw. 4. A wood waste incineration plant according to any one of claims 1 to 3, 20, characterized in that a fuel discharge cone (13) is arranged eccentrically in relation to the stoker screw channel (14). 5. Wood waste incineration plant according to any one of claims 1 to 4, characterized in that moving of the stair and floor grilles as well as support frames (16) back and forth on annular L-profiles (17) is carried out by means of hydraulics. cylinders (18), wherein a unloading cone (13) welded curved flat iron, when a support frame (16) rotates, incrementally stairs (15) in motionless and at annular outer periphery (20) welded curved flat iron (21) sets 3) step by step. 5 6. A wood waste incineration plant according to any of claims 1 to 5, characterized in that symmetrically two air ducts (22) and symmetrically four air ducts (27) through which the combustion air is conducted are arranged symmetrically. A control duct (25) for each duct is constructed of a control means (23) sealed with a bandage (24), whereby the amount of air in each duct can be controlled. 7. A wood waste incinerator as claimed in any one of claims 1 to 6, characterized by a non-combustion chamber (28), the afterburner furnace according to Figure 7 has been mounted by refractory mass cast post-combustion elements (29) next to each other. 15 8. A wood waste incineration plant according to any one of claims 1 to 7, characterized in that a sprung shaft (30) and vibration plates (36) which cut the carbon and ash in the chute (40) with a screw (30) are arranged below 41) with opposite thread, which screw moves them through a discharge cone (43) into the first combustion furnace of the post-combustion furnace, where the coal burns down and the ash falls between refractory elements (45) on the bottom of the second fuel chamber into a box chute (46). 9. A wood waste incineration plant according to any one of claims 1 to 8, characterized in that an LTO flue gas cleaner (49), to which the flue gases are led after the convection boiler (28), is provided with an acid-resistant LTO squeegee battery (50). which is fixed to a gear cover (51) which for the time of cleaning can be lifted from the side during operation and replaced by a closed door. 10. A wood waste incinerator as claimed in any one of claims 1 to 9, characterized in that the plant is equipped with a temperature transmitter (54) and a frequency converter (55) by means of which the heat generation effect is controlled by changing the rotational speed of a flue gas fan (53). 11. A wood waste incinerator according to any one of claims 1-10, characterized in that the sockets (56) and (60) of the front fireplace (32) and the post-combustion furnace are constructed of steel plate and beams to a dense water space (57) by As through-holes used in the base, penetrations that are welded to the plaque walls are coming. From the heated water spaces, the heated water is moved through circulation to adjacent accumulators (58) and (61) and cooled back. 12. A wood waste incineration plant according to any one of claims 1 to 11, characterized in that two ducts (64) and (65) are provided between the after-incinerator (62) and the convection boiler (48) on whose orifices are made of refractory mass produced closure elements (63). ) and (66) which are removable depending on the humidity and use situation of the fuel. 13. A wood waste incineration plant according to any one of claims 1 to 12, characterized in that the walls (67) of the front fireplace (32) are so walled that a space through which the combustion air is sucked is formed between the walls and an outer jacket (68). into air ducts (69) and (70) above the fireplace and thence further through separate ducts (71) and (72) at the side walls, and through the socket to the previous fireplace symmetrically arranged flow ducts (27), 4 pcs., under the stair grilles and through flow channels (22) 2 pcs.