Treatment of exhaust gas with an odor absorber

Abstract

Method for discharging exhaust gas (3) from an interior space (2) of a building (1), wherein the exhaust gas (3) is discharged from the interior space (2) of the building (1) into an environment (5) of the building (1) via an exhaust gas opening (4), wherein a solution (6) of an odor-binding agent is added to the exhaust gas (3) upstream of the exhaust gas opening (4), and wherein the odor-binding agent consists of 5 to 17 wt% 1,2-propanediol, 66 to 85 wt% triethyl citrate and 5 to 17 wt% di-propylene glycol monomethyl ether or consists of 23 to 40 wt% 1,2 propanediol, 40 to 54 wt% triethyl citrate and 23 to 40 wt% di-propylene glycol monomethyl ether.

Description

[0001] The invention relates to a method for extracting exhaust gas from the interior of a building and a corresponding use.

[0002] It is known that sewage sludge can be directly thermally utilized or conditioned to positively influence its storage, transport, or material / chemical properties for thermal utilization (incineration, gasification, pyrolysis). For this purpose, the sewage sludge is usually first stored in an intermediate storage facility and then gradually fed into an incineration process. Since sewage sludge can emit unpleasant odors, an enclosed space such as a hall or bunker is typically used as the intermediate storage facility to prevent the odors from spreading into the surrounding area as diffuse emissions. A hall or bunker offers the possibility of collecting and channeling the exhaust air stream. This controlled exhaust air flow allows for targeted treatment of the exhaust air stream. Alternatively, the hall can be fogged.However, this has the disadvantage that contact between the agent used and the exhaust air is not necessarily guaranteed. Furthermore, creeping air currents are possible. Fogging also generally leads to a disproportionate use of odor-binding agent.

[0003] Within such a potential hall, the temporarily stored sewage sludge can be handled, for example, with a wheel loader and fed into a conveying system, such as a sewage sludge pump, from which it then goes directly to thermal treatment or downstream conditioning processes. However, if a wheel loader with a combustion engine is used in an enclosed hall, the exhaust gases from the wheel loader must be vented from the interior. This inevitably releases air from the interior of the hall into the surrounding environment, which contains the unpleasant odors emanating from the sewage sludge. In addition to removing emissions from the wheel loader's operation, regular, ideally continuous, air exchange within the hall is also essential to prevent the accumulation of hazardous air components from the temporary sewage sludge storage in the hall or bunker.Therefore, there is a need to treat the exhaust air released from the hall into the surrounding area in such a way that there is no odor nuisance outside the hall.

[0004] In other applications, it may also be desirable to treat exhaust gases in such a way as to prevent or at least reduce odor nuisance. One approach to this is known, for example, from EP 3 511 026 B1. This patent describes a method for combating unpleasant odors in the exhaust air from containers, rooms, or systems in which strongly smelling substances such as feces, waste, or strongly scented foods are stored or processed. A finely dispersed fluid is introduced into the exhaust air, which neutralizes the odor of the substances contained in the exhaust air physically and / or chemically. The fluid is a 0.1% to 8% solution of an active ingredient concentrate, consisting of 55 to 65% by weight of triethyl citrate, 17.5 to 22.5% by weight of 1,2-propanediol, and 17.5 to 22.5% by weight of dipropylene glycol methyl ether.

[0005] The object of the present invention is to present an alternative method for extracting exhaust gas from the interior of a building, starting from this known approach.

[0006] This problem is solved by the method and use according to the independent claims. Further advantageous embodiments are specified in the dependent claims. The features described in the claims and in the description can be combined with one another in any technologically meaningful way.

[0007] According to the invention, a method for venting exhaust gas from the interior of a building is presented, wherein the exhaust gas is vented from the interior of the building into the building's surroundings via an exhaust gas opening, and wherein a solution of an odor-binding agent is added to the exhaust gas upstream of the exhaust gas opening, wherein the odor-binding agent consists of 5 to 17 wt% 1,2-propanediol, 66 to 85 wt% triethyl citrate and 5 to 17 wt% di-propylene glycol monomethyl ether or consists of 23 to 40 wt% 1,2 propanediol, 40 to 54 wt% triethyl citrate and 23 to 40 wt% di-propylene glycol monomethyl ether.

[0008] The described method involves extracting exhaust gas from the interior of a building. The building could be, for example, a hall or a bunker, particularly a waste storage facility. However, the functionality of the described method is independent of the building's size and purpose. The interior of the building is simply a space within the building. In particular, if the building is a hall, it is sufficient that the building has this one interior space. Whether or not the building has additional rooms besides this interior space is irrelevant to the functionality of the described method.

[0009] Exhaust gas is the gas that must be vented from the interior of a building. Exhaust gas can also be referred to as exhaust air. However, for the purposes of this described process, it is irrelevant whether it falls under the definition of air. Therefore, the term exhaust gas is used generally here. Exhaust gas can be any gas that is present in or generated within the interior of a building and that must be vented from there. For example, if a vehicle with an internal combustion engine is operated inside the building, the exhaust gas to be vented from the interior may include exhaust from the combustion engine. If, for example, sewage sludge is stored inside the building, gas emitted by the sewage sludge and / or foul-smelling air from the area of ​​the sewage sludge may be vented from the interior as part of the exhaust gas.The exhaust gas extracted from the interior using the described method can be a mixture of gases from various sources, for example from an internal combustion engine and sewage sludge.

[0010] The exhaust gas is vented from the building's interior into its surroundings via an exhaust vent. This vent forms a discrete emission point (a so-called point source) where the exhaust gas is released into the building's environment. This simplifies the assessment of the exhaust gas's impact on the environment. For example, a distance from the exhaust vent is clearly defined as the emission point. This makes calculations regarding the exhaust gas's dispersion particularly straightforward.

[0011] Apart from the exhaust vent, the interior of the building can have other openings, in particular air intake vents. The interior of the building does not necessarily have to be sealed off from the surrounding environment. The air intake vents are preferably located lower than the exhaust vent. This results in particularly good airflow. The air intake vents are preferably located near the floor.

[0012] The exhaust vent allows exhaust gases to be vented from the interior. This prevents the accumulation of particularly foul-smelling gases in the interior over time. This not only facilitates work inside the building but also allows small amounts of gas to escape from the interior, even without odor control treatment, without causing significant odor nuisance. For example, it is not a problem if a building door is briefly opened for loading and / or unloading waste products. Similarly, it is not a problem if small amounts of gas escape from the interior to the environment due to a leak in the building.

[0013] The odor-binding treatment of the exhaust gas is achieved by adding a solution of an odor-binding agent to the exhaust gas upstream of the exhaust outlet. Odors emanating from the exhaust gas are thus prevented or at least significantly reduced. Thanks to this odor-binding treatment, the exhaust gas can be released into the surrounding area without causing any odor nuisance. Therefore, it is not necessary to completely seal the building's interior airtight to prevent odor nuisance in the surrounding area. Instead, the exhaust gas can be released into the environment through the exhaust outlet as described.

[0014] A solution of the odor-binding agent is added to the exhaust gas. The odor-binding agent can be considered a concentrate, which is not added to the exhaust gas in pure form, but rather diluted with a solvent. The odor-binding agent solution is preferably between 0.1% and 10%. This refers to the ratio between the mass of the odor-binding agent and the mass of the solvent. However, the exact concentration of the odor-binding agent in the solvent is not critical. Therefore, it is not necessary to know or precisely adjust this concentration. The odor-binding agent can thus be mixed with the solvent without having to pay close attention to the ratio between the odor-binding agent and the solvent. This simplifies the process.

[0015] The concentration of the odor-binding agent in the solvent can vary over time. For example, increasing this concentration can respond to an increase in exhaust gas volume, and / or decreasing this concentration can respond to a decrease in exhaust gas volume. The exhaust gas volume can either be measured directly or determined from parameters that serve as a measure of exhaust gas volume.

[0016] The amount of odor-binding agent added to the exhaust gas can also vary over time. For example, the amount of odor-binding agent added to the exhaust gas per unit of time can be determined based on the amount of exhaust gas discharged per unit of time. The amount of exhaust gas discharged per unit of time can be adjusted, for example, by setting a fan. The amount of exhaust gas discharged per unit of time can be increased, for instance, during periods when a combustion engine vehicle is operating inside the building.

[0017] The solvent is preferably water. In this case, the solution is aqueous. However, the solvent is not essential to the functioning of the described process. Rather, the solvent merely serves as a carrier for the odor-binding agent. The solvent can also be in vapor form.

[0018] The odor-binding agent is the substance that binds odors. The odor-binding agent can therefore be described as the active substance or an active ingredient.

[0019] The odor-binding agent consists of 5 to 17 wt% 1,2-propanediol, 66 to 85 wt% triethyl citrate and 5 to 17 wt% di-propylene glycol monomethyl ether (first alternative) or of 23 to 40 wt% 1,2-propanediol, 40 to 54 wt% triethyl citrate and 23 to 40 wt% di-propylene glycol monomethyl ether (second alternative).

[0020] It is known from the prior art that an odor-binding agent consisting of 17.5 to 22.5 wt% 1,2-propanediol, 55 to 65 wt% triethyl citrate, and 17.5 to 22.5 wt% dipropylene glycol methyl ether has an odor-binding effect on exhaust gas. According to the invention, it was discovered that an odor-binding effect can also be observed with odor-binding agents according to the two previously mentioned alternatives. This is surprising insofar as the proportions of all three components were changed. There are unlimited possibilities for changing the composition of a substance consisting of three components.According to the invention, it was recognized that good results can be achieved by reducing the proportion of 1,2-propanediol and the proportion of di-propylene glycol monomethyl ether while increasing the proportion of triethyl citrate (first alternative) or by increasing the proportion of 1,2-propanediol and the proportion of di-propylene glycol monomethyl ether while decreasing the proportion of triethyl citrate (second alternative).

[0021] The odor-binding agent most preferably consists of 5 to 12 wt% 1,2-propanediol, 70 to 85 wt% triethyl citrate, and 5 to 12 wt% dipropylene glycol monomethyl ether (first alternative) or of 28 to 40 wt% 1,2-propanediol, 40 to 49 wt% triethyl citrate, and 28 to 40 wt% dipropylene glycol monomethyl ether (second alternative). In this embodiment, the composition differs significantly from the prior art.

[0022] In a preferred embodiment of the method, the exhaust gas is collected inside the building, and the odor-binding agent solution is subsequently added to the exhaust gas.

[0023] As an alternative to this embodiment, the odor-binding agent solution can also be sprayed inside the building. In this case, the solution would be diffusely distributed throughout the interior. However, it has proven more efficient to first collect the exhaust gas and then treat it with an odor-binding agent. In the present embodiment, the exhaust gas is therefore first collected inside the building. This can be achieved using a collection device. This device can, for example, draw in the exhaust gas at one or more points and direct it to the exhaust outlet. The collection device can, for example, include a fan, in particular an axial fan – because it is space-saving and reduces noise when mounted in the area of ​​the building's roof. The odor-binding treatment of the exhaust gas can take place immediately before the exhaust outlet.Preferably, the solution of the odor-binding agent is mixed with the exhaust gas between the collection device and the exhaust gas opening.

[0024] Alternatively, the odor-binding agent solution can also be introduced directly into the exhaust gas within the collection system, for example, at the suction side of a fan in the collection system. This can create turbulence within the collection system, which can be used to improve the distribution of the odor-binding agent in the exhaust gas being treated.

[0025] In general, it is preferred that the distance between the point where the exhaust gas is treated with the odor-binding agent and the exhaust gas opening is as large as possible, so that the residence time of the odor-binding agent in the exhaust gas is as long as possible.

[0026] In another preferred embodiment of the method, the exhaust gas opening is formed at one end of a chimney.

[0027] The chimney can also be called a flue. The flue outlet is located at one end of the chimney. The other end connects the chimney to the interior of the building. This end of the chimney is preferably connected to a collection device that gathers the flue gases inside the building. The chimney preferably has an inner diameter of 1 to 3 meters, for example, 2 meters.

[0028] The odor-binding agent is preferably added to the exhaust gas inside the chimney, particularly preferably in a vertically oriented section of the chimney. The exhaust gas is collected within the chimney, allowing for particularly effective treatment of the exhaust gas within the chimney.

[0029] To increase the mixing of the solution and the exhaust gas, a static mixer can be installed in the chimney. Alternatively or additionally, compressed air and / or atomizing vapor can be introduced into the chimney to mix the solution and the exhaust gas. The atomizing vapor is preferably introduced into the chimney at a pressure in the range of 6 to 20 bar.

[0030] There are various ways to mix the odor-binding agent solution with the exhaust gas inside the chimney. The two following embodiments are examples of this. These can also be used in combination by mixing the odor-binding agent solution with the exhaust gas in each of the two ways described.

[0031] In another preferred embodiment of the method, the solution of the odor-binding agent is introduced into the chimney via a ring nozzle.

[0032] A ring nozzle allows for particularly good distribution of the solution across a cross-section of the chimney.

[0033] In another preferred embodiment of the method, the solution of the odor-binding agent is introduced into the chimney via a nozzle lance.

[0034] Using a nozzle lance, the solution can be mixed with the exhaust gas via an axially extended section of the chimney. This is particularly true in the preferred case where the nozzle lance is aligned parallel to the chimney. However, the advantage can also be achieved to a limited extent if the nozzle lance is aligned at an angle to the chimney.

[0035] In another preferred embodiment of the method, the solution of the odor-binding agent is introduced into the chimney in countercurrent flow to the exhaust gas.

[0036] It has been found that the exhaust gas and the solution can mix particularly well in this embodiment.

[0037] Introducing the product in a counter-current flow can create turbulence and thus mixing. This helps prevent clumping.

[0038] Alternatively, it is also possible to introduce the odor-binding agent solution into the chimney in parallel with the exhaust gas.

[0039] In another preferred embodiment of the method, a waste product is moved inside the building using a vehicle with an internal combustion engine.

[0040] The vehicle with an internal combustion engine emits exhaust gases during operation, which can be extracted from the building's interior using the described method. This allows the vehicle to be operated inside the building. While it is generally not necessary to treat the vehicle's exhaust gases with an odor-binding agent, the exhaust gases cannot simply be extracted from the building's interior without simultaneously releasing a foul-smelling gas emitted by the exhaust gases.

[0041] The vehicle could be, for example, a wheel loader. The vehicle can be used to, for example, load and / or unload the waste product.

[0042] In another preferred embodiment of the process, the waste product is sewage sludge.

[0043] The sewage sludge can be temporarily stored in the building and subsequently thermally treated. In this case, the building is preferably designed as a hall. Inside the building, the temporarily stored sewage sludge can be conveyed, for example, by a wheel loader to a sludge pump, from which it is then transported to the incineration plant. The wheel loader can also be used to move the sewage sludge in and out of the building.

[0044] The sewage sludge is preferably stored inside the building as part of the described process and transported by a combustion engine vehicle to a process in which the sewage sludge is thermally treated or conditioned. Conditioning can positively influence the storage, transport, or material / chemical properties of the sewage sludge for thermal treatment (incineration, gasification, pyrolysis). In this case, the process is one for the thermal treatment or conditioning of sewage sludge and for the removal of exhaust gas from the interior of a building.

[0045] Alternatively, the waste product could also be, for example, fermentation sludge or material from a household waste composting process, which is to be subjected to mechanical and / or biological waste treatment.

[0046] As a further aspect of the invention, a use of a solution of an odor binder for the treatment of an exhaust gas is presented, wherein the odor binder consists of 5 to 17 wt% 1,2-propanediol, 66 to 85 wt% triethyl citrate and 5 to 17 wt% di-propylene glycol monomethyl ether or consists of 23 to 40 wt% 1,2 propanediol, 40 to 54 wt% triethyl citrate and 23 to 40 wt% di-propylene glycol monomethyl ether.

[0047] The described advantages and features of the described device are applicable and transferable to its use, and vice versa.

[0048] The invention is explained in more detail below with reference to the figures. The figures show particularly preferred embodiments, to which, however, the invention is not limited. The figures and the size relationships shown therein are only schematic. They show: Fig. 1: a building in which exhaust gas is extracted from an interior space according to a method according to the invention, Fig. 2: a cross-sectional view of part of the chimney made of Fig. 1 in a first embodiment, Fig. 3: A cross-sectional view of part of the chimney made of Fig. 1 in a second embodiment.

[0049] Fig. Figure 1 shows a building 1 with an interior space 2. Sewage sludge, a waste product 11, is stored in the interior space 2. The sewage sludge is moved by a vehicle 12. In this example, the vehicle 12 is a wheel loader. The sewage sludge can, for example, be fed by the wheel loader to a sewage sludge pump (not shown). The sewage sludge can then be pumped, for example, to an incinerator.

[0050] Exhaust gas 3 forms in the interior space 2 of building 1. This is due, on the one hand, to the fact that the sewage sludge releases a gas and, on the other hand, to the fact that the vehicle 12 is operated with an internal combustion engine 13. The exhaust gas 3 is collected within the interior space 2 via a collection device 14 and then discharged to the surrounding area 5 of building 1 via an exhaust opening 4. The exhaust opening 4 is located at one end 7 of a chimney 8.

[0051] Fig. Figure 2 shows an enlarged view of the fireplace 8. Fig. 1 in a first embodiment. A ring nozzle 9 is formed inside the chimney 8. Upstream of the exhaust gas opening 4, an aqueous solution 6 of an odor-binding agent is mixed with the exhaust gas 3. This occurs downstream of the collecting device 14, i.e., between the collecting device 14 and the exhaust gas opening 4. The aqueous solution 6 of the odor-binding agent is introduced into the chimney 8 in co-current flow with the exhaust gas 3.

[0052] The odor-binding agent consists of 5 to 17 wt% 1,2-propanediol, 66 to 85 wt% triethyl citrate, and 5 to 17 wt% dipropylene glycol monomethyl ether, or of 23 to 40 wt% 1,2-propanediol, 40 to 54 wt% triethyl citrate, and 23 to 40 wt% dipropylene glycol monomethyl ether. The addition of the odor-binding agent neutralizes odors in the exhaust gas 3. The exhaust gas 3 can therefore be released into the environment 5 without causing any odor nuisance there. This makes it possible to operate the vehicle 12 with the combustion engine 13 in the interior 2 of building 1.

[0053] Fig. Figure 3 shows an enlarged view of the fireplace 8. Fig. 1 in a first embodiment. In contrast to Fig. 2. A nozzle lance 10 is formed inside the chimney 8. Upstream of the exhaust gas opening 4, an aqueous solution 6 of an odor-binding agent is mixed with the exhaust gas 3. Otherwise, the same applies to Fig.2. As stated above, in particular regarding the composition of the odor-binding agent. Reference symbol list 1 building 2 Interior 3 Exhaust gas 4 Exhaust opening 5 Environment 6 Solution 7 End 8 fireplace 9 ring nozzle 10 nozzle lances 11 Waste product 12 vehicles 13 Internal combustion engine 14 Collection facility QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] EP 3 511 026 B1

[0004]

Claims

[1] Method for discharging exhaust gas (3) from an interior space (2) of a building (1), wherein the exhaust gas (3) is discharged from the interior space (2) of the building (1) into an environment (5) of the building (1) via an exhaust gas opening (4), wherein a solution (6) of an odor-binding agent is added to the exhaust gas (3) upstream of the exhaust gas opening (4), and wherein the odor-binding agent consists of 5 to 17 wt% 1,2-propanediol, 66 to 85 wt% triethyl citrate and 5 to 17 wt% di-propylene glycol monomethyl ether or consists of 23 to 40 wt% 1,2 propanediol, 40 to 54 wt% triethyl citrate and 23 to 40 wt% di-propylene glycol monomethyl ether. [2] Method according to claim 1, wherein the exhaust gas (3) is collected inside the interior (2) of the building (1), and wherein the solution (6) of the odor binder is subsequently mixed with the exhaust gas (3). [3] Method according to one of the preceding claims, wherein the exhaust gas opening (4) is formed at one end (7) of a chimney (8). [4] Method according to claim 3, wherein the solution (6) of the odor-binding agent is introduced into the chimney (8) via a ring nozzle (9). [5] Method according to claim 3 or 4, wherein the solution (6) of the odor binder is introduced into the quay (8) via a nozzle lance (10). [6] Method according to any one of claims 3 to 5, wherein the solution (6) of the odor binder is introduced into the chimney (8) in countercurrent flow to the exhaust gas (3). [7] Method according to one of the preceding claims, wherein a waste product (11) is moved in the interior (2) of the building (1) by means of a vehicle (12) with an internal combustion engine (13). [8] Method according to claim 7, wherein the waste product (11) is sewage sludge. [9] Use of a solution (6) of an odor binder for the treatment of an exhaust gas (3), wherein the odor binder consists of 5 to 17 wt% 1,2-propanediol, 66 to 85 wt% triethyl citrate and 5 to 17 wt% di-propylene glycol monomethyl ether or consists of 23 to 40 wt% 1,2 propanediol, 40 to 54 wt% triethyl citrate and 23 to 40 wt% di-propylene glycol monomethyl ether.

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