HU192582B - Boiler for heat utilization of combustion products of high dust content particularly for applying at refuse firing - Google Patents

Abstract

The invention relates to a boiler for thermal use of combustion products with a high content of pulverulent products, and fitted with a radiation chamber delimited by tubular walls and followed by a group of tubular bundles. The vaporisation tubular bundles 10 placed in the second passage of the boiler are disposed vertically and welded at the top and bottom with tubular collectors 11, 12, the lower collectors 11 being staggered and there is provided a collector volume for light ashes 7 which is fitted with separating plates 15 and which comprises a screw 14 for discharging the light ashes. Application to heating with highly pulverulent fuels. <IMAGE>

Description

BACKGROUND OF THE INVENTION The present invention relates to a boiler for the thermal utilization of high dust combustion products, in particular for use in waste incineration.

The design of the boiler according to the invention provides an opportunity to efficiently cool or heat the combustion products containing high dust or unfavorable airborne particulate matter. The present invention is applicable primarily to so-called waste incineration (for example, sunflower kernels), but also to so-called heat recovery boilers using the cooling of hot gases from other technologies.

It is common for waste fires, such as sunflower firing, to contain a large amount of so-called fly ash from the combustion plant, which causes severe operational problems and frequent stoppages when deposited on the convective heating surface of the boiler. Large scale deposition reduces heat transfer and efficiency.

The boilers used in the industry in this field generally employ conventional gas or oil-fired designs and are adapted for this purpose. This is also due to the fact that today the combustion of waste or other combustible residues followed the "hydrocarbon era" and were no longer adequate for the conventional steam power of 2-15 t / h, ie modern designs.

Boilers connected to waste incineration can basically be divided into two groups: the so-called chip and water pipe structures.

Flue gas boilers include a conventional hydrocarbon fired backhaul boiler with a chilled ballast in front of a flame pipe (such as the Austrian 1IDMRS 600). The disadvantage of these designs is that the dust captured by the flue gas in the small radiant space does not cool below the softening limit temperature and therefore adheres to the heating surface of the boiler. The cleaning of such a deposit is cumbersome and time consuming. In another version of the flue gas boilers, a large radiant space is located adjacent to the subsequent flue gas boiler (e.g., the FGH FG type boiler). In this gas, the captured fly ash can be cooled below the softening point in the combustion chamber so that no solidified and difficult to remove layer is deposited on the tubes. The disadvantage of this design is that, due to the wall thickness of the large diameter flue gas boiler, it is approx. Above the power range of 8 t / h it can only be used for medium pressures (max. 20 bar). Another difficulty with these flue gas boilers is that they have to stop with the boiler to clean ("pull out") the flue pipes, which significantly reduces the number of hours of use.

Water-tube boilers eliminate these disadvantages by providing virtually unlimited pressure and can be cleaned during operation without stopping the boiler (for example, the Austrian BERTS boiler at the Vegetable Oil Plant in Martfű). By increasing the pressure, it is possible to make full use of the steam generated from the incineration, for example, to drive a steam turbine at a factory power plant. Such water-tube boilers are made in the conventional power-stationary two-pipe or multi-pipe design, or in the compact design, usually in the form of a corner pipe, in the power range normally used for waste incineration. These boilers have horizontal convective pipes and have been found to be prone to deposition.

In one of the known types of vertical convective pipe-type boilers, the convective pipes are welded between the flue gas boundary pipes (for example, Weiss FRP plant Compact II / 250-UVD). For flue gas deflection, horizontal plates are provided which, in flue gas cleaning (for example, steam or compressed air), are co; they shield the space from the jet-blast beam. The hostel is ^one falling ash collects in the bottom of the cover, remove: not solved. In the case of major overhauls or replacements that occur over a period of time, access to convective pipes can only be achieved by cutting the boiler side wall pipes.

In a further embodiment, the vertical tubes are welded between two longitudinal drums, which is also a disadvantage in terms of cleaning and tube replacement (e.g.

It is an object of the present invention to provide a boiler installation which eliminates the drawbacks of the above-described constructions and is suitable for continuous, economical operation even with unfavorable combustion products containing high ash content.

This object is achieved by a boiler design in which: - the convective pipes are vertical..and therefore insensitive to dust deposition, - the convective pipe bundles are well blown with sootblowers, Replacing bundles or curtains is quick and easy.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a boiler for the thermal recovery of high dust combustion products having an upper irradiated compartment and two water pipe passages. The boiler is located below the first draft of the boiler, while the boiler is equipped with a steam drum, superheater and feedwater heater. In the second pass of the boiler, the superheated, convective, bundles of tubes are arranged. The boiler walls are made up of steam-tightly joined pipes.

The essence of the invention is that the evaporative tube bundles in the second passage of the boiler consist of a vertical shaft, welded with bottom and top tube chambers, placed behind one another. The lower manifold chambers are always arranged offset from the adjacent manifolds. Underneath the first and last tubing chambers is an ash collecting space with diaphragm plates having an ash-carrying member, such as a snail.

According to a preferred embodiment of the invention, the bundles of tubes are extensible from the boiler in a cassette-like manner.

According to a further preferred embodiment, the convective draft tube boundary walls are welded to the lower portion of the draft, alternately in the rear and the first tube chamber.

In a further preferred embodiment, the outer walls of the pipe walls defining the boiler flow have a gas-tight plate cover formed by trays, and the trays are joined to one another by lip welding. The trays are secured by comb-coupling plates and horizontal U-shaped holding irons spaced to the pipe walls.

Advantages of the above described boiler structure 65 are as follows:.

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- II. Containing convective bundles. The design of the draft is such that it is particularly suited to cooling down combustion products containing high ash content by:

(a) consist of vertical beakers with a minimum deposition,

(b) vertical pipes are favorable for natural circulation,

(c) ash from the bundles is cleaned with sootblowers and is discharged into the collection trough and thus releases less contaminants through the chimney;

(d) the fly ash can be continuously removed from the collecting troughs by means of a conveyor.

- Tube bundles are simple and inexpensive to design.

- In the case of overhaul, the bundles can be pulled out of the boiler in a cassette-like manner.

- The boiler frame and pipe walls are self-supporting, the steam drum stands on the drop pipes, the boiler does not have a separate support structure.

The bottom of the irradiated space can be connected to any combustion apparatus.

- The gas-tight sheet metal cover on the outside of the pipe walls can be easily disassembled by grinding lip welds at the required location.

- Burners can be installed on the front wall of the 1st I, if necessary, for replacement or additional firing.

An exemplary embodiment of the boiler of the present invention will be described in greater detail on the basis of the drawing. The la. Figure 1b is a horizontal sectional view of the boiler according to the invention; Figure 30 is a cross-sectional view of the boiler of the present invention; Fig. 2A shows a part of the ash collecting trough of the boiler according to the invention, a

Fig. 2 schematically illustrates a convective evaporative tube bundle and a

Figure 3 illustrates the boundary walls of boiler flows. 35

As shown in Figure 1, the boiler has two layouts, which are lying down, after which the feed water heater can be placed as desired. The firing device 1 is located below the boiler. The steam drum 5 is located above the irradiated space. The combustion product flows from this into the so-called radiant space I of the boiler 40. This space is delimited by the heated pipe walls 2. The tubes of the tubular walls 2 are welded into distribution chambers 3 and collecting chambers 4. The latter also form the frame of the boiler structurally. The bottom tubes 19 of the radiating space are spaced 45, the fly ash falling through the gaps is transferred to a collecting funnel not shown.

II. The wire is located adjacent to the radiating space, the two being separated in a gas-tight manner by a so-called membrane tubular wall 6, at the rear of which the flue gas flows through the second part II. huzamba.

This radiating space is also delimited by tubular walls 2, which, in accordance with the temperature of the flue gas, are made in close proximity to each other in the warmer part, with a gas-tight rear panel cover 16 and a heat seal 55 in the other. The lower part of this radiating space is enveloped by a tube wall 2. The size of the gaps is preferably the same as the tube diameter. Through these gaps, fly ash falls into the fly ash compartment 7. The superheater 8 consists of suspended U-shaped vertical tubes and can be pulled out of the bulb 60 laterally through the gaps in the side tubes of the tube wall 2.

Figure 2 shows that the convective evaporative tube assembly 9 consists of vertical tube grids 10. The vertical pipes of the lattice grid 10 are welded at the top and bottom into a manifold chamber 65 and a manifold chamber 12. The manifold chambers 12 are inclined upwardly in accordance with natural circulation. The collector tube chambers 12 of the lattice grids 10 are connected to a tube chamber 13. The entire evaporation tube assembly 9 can be pulled out of the boiler in a cassette-like manner, laterally. The close proximity of the A-upper collecting manifolds 12 also limits the smoke passage. The lower manifold chambers 11 are offset in a vertical direction, this arrangement ensures that the fly ash passes through the flue collector trough 7, while at the same time all the down manifolds shield from the heat the lower ash collector space underneath with a discharge device such as a auger. Transverse sealing plates 15 are provided in the ash collecting trough 7 for closing the flue gas stream. These are connected to the lower manifolds 11 of the evaporator beams by a beard. From the lower part of the ash collecting trough 7, the mechanical discharge device 14, for example a horizontal screw, carries the collected ash. The shaft of the auger is cooled by the air supplied by the so-called secondary combustion air fan.

Figure 3 shows that the wall 2 of the boiler flanges is a so-called skin-casing pipe wall with a gas-tight rear panel 16 behind the closely spaced pipes. The rear panel cover 16 consists of folded-flanged trays which are connected horizontally to the U-shaped profile profiles by so-called lip welding. U-profiles are welded to the pipe walls with combs 18 in some places.

In the beaker grid 10 there is provided a soot blower 22.

Claims (4)

Claims 1. A boiler for the heat recovery of high dust combustion products having a superposed irradiation space and two horizontal drafts, the combustion apparatus located below the first boiler draft, and the boiler is equipped with a steam drum, superheater and steam water heater, and convective) pipe bundles are arranged and the boiler boundary walls are formed by gas-tightly joined pipes, characterized in that the steaming pipe bundles (11, 12) of the boiler in the second passage of the boiler ), and that the lower distribution chambers (11) are always offset in the vertical direction relative to the adjacent chambers (11) and that the ash collecting space (7) with compartments (15) under the first and last chambers (11) is extinguished provided with a fly ash carrier such as a screw (14). Boiler according to Claim 1, characterized in that the bundles (9) of the boiler are projected out of the boiler in a cassette-like manner. Boiler according to one of Claims 1 or 2, characterized in that the pipe walls (2) delimiting the convective draft are welded alternately in the lower part of the draft, in the rear and first distribution chambers (3). 4. Boiler according to any one of claims 1 to 3, characterized in that the gas-tight sheet cover (16) on the outer side of the boiler pipe walls (2) has a tray design, and that the trays are (18) and horizontal U-shaped brackets (17).