FLUE GAS FILTER SYSTEM

Abstract

flue gas filter system comprising a filter housing (21) with side walls (22) defining an interior space (23) and at least one filter element (24) arranged in the interior space (23) of the filter housing (21), characterized in that at least one capillary element (42) is present between the side walls (22) and the at least one filter element (24).

Description

[0001] The invention relates to a flue gas filter system, according to the preamble of claim 1.

[0002] To prevent large quantities of fine dust produced during combustion from being released into the environment, flue gas filter systems are provided.

[0003] From GB 650852 A a flue gas filter system is known which includes a filter housing with side walls that define an interior space and a filter element that is arranged in the interior space of the filter housing.

[0004] The combustion material, such as wood waste or wood chips, often has a high water content, so the flue gas produced during combustion also contains a high water content. The flue gas filter system for filtering the flue gas is usually located outside a building and is therefore exposed to the local temperatures, especially in winter.

[0005] If the flue gas filter system has a temperature below 60° Celsius, the water contained in the flue gas condenses and settles on the inside of the side walls. This condensed water binds to the fine dust present inside and hardens it during the next drying cycle. The hardened fine dust clogs at least parts of the filter element and is difficult, if not impossible, to remove from the filter housing.

[0006] To prevent condensation in flue gas filter systems, it is known to heat the flue gas filter system by means of a heating device so that the temperature in the flue gas filter system never falls below 60° Celsius.

[0007] A disadvantage of this known solution is that heating requires additional energy, and the energy demand is particularly high in winter to maintain the flue gas filter system temperature at the desired level. A drop in temperature within the flue gas filter system, and thus the need to heat it, can occur even during brief interruptions of the combustion process. A temperature drop can also occur, for example, when the combustion furnace is operated at partial load.

[0008] To reduce the heating requirements for flue gas filter systems to prevent condensation, well-known flue gas filter systems are also equipped with external insulation, which usually completely surrounds the filter housing of the flue gas filter system.

[0009] A disadvantage of this known solution is that the inside of the filter housing can still cool down to such an extent that condensation occurs in the filter housing, and therefore the flue gas filter system still needs to be heated separately.

[0010] The object of the present invention is therefore to create a flue gas filter system which does not have the aforementioned disadvantages and in particular requires no or only a small amount of separately supplied heating energy compared to the flue gas filter systems already known.

[0011] The problem is solved by the features of the independent claim. Advantageous developments are set out in the figures and in the dependent claims.

[0012] According to the invention, at least one capillary element is present between the side walls and the at least one filter element.

[0013] The capillary element, at least one of which is present, absorbs any water vapor, water, or condensation that may be present in the flue gas. As the temperature increases, the water contained in the capillary element evaporates and is carried away by the flue gas exiting the flue gas filter system.

[0014] The at least one capillary element is advantageously arranged directly on the side walls or with an air gap on the inside, i.e. facing the interior.

[0015] The insulation created by at least one capillary element extends the time before the side walls of the filter housing, which are usually made of steel, cool down to the point where condensation can form inside the filter housing. Even when the combustion furnace is operating at partial load or is shut down for a short period, the internal insulation reduces condensation of water vapor present in the filter housing. Furthermore, the risk of condensation is reduced during each start-up phase of the combustion furnace.

[0016] The situations in which the flue gas filter system needs to be heated to a temperature of 60° Celsius using a separate heating device are significantly reduced compared to prior art designs. If the flue gas filter system does require heating with a separate device, the necessary temperatures are reached quickly due to the capillary element located inside the filter housing, thus significantly reducing the energy required to heat the flue gas filter system compared to previous solutions.

[0017] If the flue gas filter system has a residual heat utilization or a residual heat recovery system, the system profitability (Rol = Return on Investment) is achieved much earlier due to the elimination or at least the low energy requirement for heating the flue gas filter system.

[0018] In extremely low outside temperatures, the flue gas filter system according to the invention can additionally be provided with external insulation.

[0019] Preferably, the capillarity of at least one capillary element is greater than 50 vol.%, enabling it to absorb a large quantity of water or condensation as needed. Advantageously, the capillarity of at least one capillary element is greater than 60 vol.%, providing an even greater absorption capacity.

[0020] Preferably, at least one capillary element is plate-shaped and has a length, a width that is less than or equal to the length, and a thickness. A capillary element designed as a capillary plate has particularly advantageous properties for use in a flue gas filter system and is easy to manufacture or integrate into the flue gas filter system.

[0021] Preferably, the thickness corresponds to 0.05 to 0.13 times the width. Such a capillary element can be manufactured with sufficient strength, so that even large-scale flue gas filter systems are feasible.

[0022] Advantageously, the thickness corresponds to 0.08 to 0.11 times the width of the at least one plate-shaped capillary element, which allows it to be manufactured with optimized strength while maintaining sufficient serviceability.

[0023] At least one capillary element is made of a material that is sufficiently heat-resistant to withstand the temperatures of the flue gas occurring in the flue gas filter system.

[0024] Preferably, at least one capillary element is at least partially made of calcium silicate (CaSiO3), since this material has advantageous material properties for the intended use. It is particularly advantageous if the entire capillary element is made of calcium silicate.

[0025] Further advantages, features and details of the invention will become apparent from the following description, in which exemplary embodiments of the invention are described with reference to the drawings.

[0026] The list of reference numerals, like the technical content of the patent claims and figures, forms part of the disclosure. The figures are described coherently and comprehensively. Identical reference numerals denote identical components; reference numerals with different indices indicate functionally identical or similar components.

[0027] This shows: Fig. 1. A flue gas filter system according to the invention in a side view, Fig. 2 the flue gas filter system in a section along line II-II in Fig. 1, Fig. 3 an insulation insert of the flue gas filter system in the floor plan, Fig. 4 the insulation insert acc. Fig. 3 in a side view, and Fig. 5 the flue gas filter system acc. Fig. 1 in an exploded view.

[0028] The in the Fig. 1, Fig. 2 and Fig. The flue gas filter system 11 with residual heat recovery, shown in Figure 5, comprises a filter housing 21 mounted on a stand 31. The bottom section 33 of the filter housing 21 has a funnel-shaped design with a dust outlet 34. A transport container 36, such as a big bag, is connected to the dust outlet 34 and can be disconnected from the flue gas filter system 11.

[0029] In the illustrated embodiment, the filter housing 21 has a connection nozzle 26, to which an exhaust gas line of a combustion furnace (not shown here) is connected, as well as two outlet nozzles 27, through which the filtered flue gas can escape into the environment.

[0030] The steel filter housing 21 has four side walls 22 that define an interior space 23. In this exemplary embodiment, the square interior space 23 of the filter housing 21 contains several flat hose filters as filter elements 24 and two heat exchanger elements 25.

[0031] If the filter elements 24 are covered with fine dust, they are dedusted, for example, by means of a burst of compressed air, whereby the dissolved fine dust falls through dust outlet 34 in the bottom section 33 of the filter housing 21 into the transport container 36 and thus the fine dust collected therein can be safely disposed of.

[0032] Between the side walls 22 and the filter elements 24, an insulation 41 is present on the inside of each side wall. The insulation 41 is formed by several plate-shaped capillary elements 42 (capillary plates), each having a length L, a width B that is smaller than the length L, and a thickness D ( Fig. 3 and Fig. 4) The thickness D corresponds to 0.05 to 0.13 times, advantageously 0.08 to 0.11 times, the width B. Each plate-shaped capillary element 42 has the same dimensions. Four capillary elements 42 are assembled to form a frame 43. As can be seen in particular from the Fig. As can be seen in Figure 5, several frames 43 are arranged one above the other, so that over the entire height H of the side walls 22 of the filter housing 21 these are provided on the inside with the insulation 41.

[0033] Each capillary element 42 is made of calcium silicate. The capillarity of the capillary elements 42 is greater than 50 vol.%. A capillarity greater than 60 vol.% is particularly advantageous. The capillary elements 42 absorb moisture present in the filter housing 21 and release it again as the temperature increases.

[0034] The individual parts of the filter housing are screwed together (see also Fig.5) and not welded together, as is usually the case in prior art. The screw connections can be loosened as needed, thus opening the filter housing to, for example, replace defective elements of the flue gas filter system 11 or existing elements with newer generation elements. This gives the flue gas filter system 11 a significantly longer service life compared to previous systems. The flue gas filter system 11 can also be continuously updated to the latest technological standards. Reference symbol list 11 Flue gas filter system 21 filter housings 22 side wall 23 Interior 24 filter elements 25 Heat exchanger element 26 connection spigots 27 outlet nozzles 31 Stand construction 33 Ground section v. 21 34 Dust outlet 36 transport containers 41 Insulation 42 capillary elements 43 frames H Height v. 21 B Width v. 42 D Thickness v. 42 L Length v. 42

Claims

[1] Flue gas filter system comprising a filter housing (21) with side walls (22) defining an interior space (23) and at least one filter element (24) arranged in the interior space (23) of the filter housing (21), characterized by , that at least one capillary element (42) is present between the side walls (22) and the at least one filter element (24). [2] Flue gas filter system according to claim 1, characterized by , that the capillarity of at least one capillary element (42) is more than 50 vol.%, advantageously more than 60 vol.%. [3] Flue gas filter system according to claim 1 or 2, characterized by , that at least one capillary element (42) is plate-shaped and has a length (L), a width (B) which is less than or equal to the length (L), and a thickness (D). [4] Flue gas filter system according to claim 3, characterized by, that the thickness (D) corresponds to 0.05 to 0.13 times, advantageously 0.08 to 0.11 times, the width (B). [5] Flue gas filter system according to one of claims 1 to 4, characterized by , that the insulation (41) is at least partially made of calcium silicate.

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