FI92520B - Labyrinth chamber - Google Patents

Abstract

Design modification to the furnace 5 of a boiler 1 for burning timber waste. A labyrinth chamber 12 has been fitted to the support for the carrier pipes 8, the walls 13 of which chamber guide the flue gas into a heat- insulated 10 furnace. The flue gas is thereby kept at a sufficiently high temperature (800 ... 1000 degrees C) for the time laid down in the emission standards (0.5 ... 1 s). <IMAGE>

Description

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SOCKET CHAMBER

The invention relates to a furnace for a wood waste incinerator and an associated afterburner, i.e. a hot chamber, on which two basic requirements are generally set;

The minimum temperature of the flue gas after the hot chamber must be at least 800 ... 1000 ° C,

The flue gas should remain in the hot chamber for at least 0.5 ... 1 s. Conventional fireboxes and afterburners are continuous spaces formed by either a triangle or a cylinder 10. The natural consequence of such a design is uneven temperature in different parts of the chamber. The flue gas flowing in the center is usually hot enough even at low powers, but in the vicinity of the walls the temperature remains so low that the cyanogen hydrogen formed in the pyrolysis of particle board waste does not burn but goes with the flue gas 15 to the outside air. The phenomenon is clearly demonstrated in a study by VTT's HVAC Technology Laboratory: "Emissions from heat production in the furniture industry / VTT 1254".

The object of the invention is to eliminate this disadvantage by achieving a sufficiently high and uniform temperature which, under oxidizing conditions, converts cyanide into hydrogen as nitrogen and carbon dioxide gases and into water vapor.

The concentration is characterized by what is presented in the symbol part of the main claim.

25

The concentration will be described in detail below by means of an action example, with reference to the accompanying drawing. Figure 1 shows a section of wood waste: combustion boiler (1) seen from the side. The wood waste (3) burning on the grate (2) is burned to the end by means of additional air (4) in the furnace (5), 30 from which the flue gas passes through the outlet (15) to the cooling section (6) and from there through the flue (7) to the outside air. Figure 2 shows a side section of the above-mentioned wood waste incinerator (1) after the modification work according to the invention. A service hatch (8) has been made in the side wall of the firebox (5) for installation work, and water-cooled support pipes (9) have been installed above the combustion chamber.

35 The walls and roof of the firebox above the support pipes are lined with fireproof thermal insulation (10). Mounted on the support tubes are ceramic moldings (11) which form the base for the partitions (13) of the maze chamber (12). The fire gas rises into the maze chamber from the opening (14) and exits through the opening (15) to the boiler cooling section (6) as well as ku-4’C pulp 1, but support columns (16) are installed in this opening to support the roof thermal insulation (10).

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Alternatively, instead of the maze chamber according to Fig. 2, a solution according to Finnish patent 84750 (F23 G 5/16) can also be applied, in which the flue gas is directed in the hot chamber in a vertical flow alternately 45 downwards and upwards. Technically, however, it is more cumbersome because thermally conductive steel ties must be used to insulate the roof of the hot chamber and care structures must be made under the walls for the flow channel. In the horizontal flow solution according to Figure 2, the thermal insulation of the roof remains on the lid of the flow channel and the turning points of the flow channel 50 are formed by themselves at the end of the maze wall (13), without special structures.

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Claims (1)

-3- 92520 CLAIMS A refractory maze chamber (12) to be installed in the furnace (5) of a wood waste incinerator, the function of which is to direct the flue gas flow generated during combustion as hot as possible so that harmful hydrocarbon compounds decompose and oxidize, characterized by flow diverting partitions (13 and 16) and outer walls (10 and 11) made of refractory thermal insulation material, which prevent heat from conducting to the firebox surfaces and that the flow cross-section at the inlet (14) of the maze is smaller than at the outlet (15). 92520 I eldstaden (5) av en put on förbränning av stringesavfall in-monterbar labyrintkamerare (12) stem uptake and can be used for the construction of the uptake under the furrow undercutting in the form of a fuse with a single piston-shaped fuse, att chamber chamber construction- · - important for the use of internal heating equipment (13 and 16) in the case of gas-fired construction equipment (10 and 11) with the use of high-strength insulating materials, low-cost safety of the energy supply, the labyrinth chamber (14) does not have a high density (15). II