JP2018185127A - Purification of flue gas, and reheating method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat exchanger for reheating a flue gas after cleaning flue dust to prevent contamination by hard solid deposit.SOLUTION: A flue gas of high temperature is passed through a heat exchanger 2 while radiating heat, then passed through a flue gas purifier 6, then passed through the heat exchanger 2 while absorbing heat, and then supplied to a chimney 15. Here, the flue gas is passed through a liquid separator 9 at a downstream side of the flue gas purifier 6 and an upstream side of the heat exchanger 2 when observed in a flowing direction S. By disposing the additional liquid separator comparatively near the heat exchanger, condensation water droplets are formed between the liquid separator and the heat exchanger, so that the condensation water droplets can prevent a problem on contamination by solid deposit in the heat exchanger.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for purifying and reheating flue gas, in which the hot flue gas flows through a heat exchanger while dissipating heat, then flows through a flue gas purifier, and then absorbs heat. Then, the heat exchanger is passed through and then supplied to the chimney. The present invention further relates to an apparatus for purifying and reheating flue gas flowing in a predetermined flow direction, and the apparatus includes a heat exchanger casing through which a gas for reheating flows and a heat exchange member.

  Such a method and apparatus are used, for example, for the purification of flue gas in coal or oil-fired power plants (hereinafter both abbreviated as “power plants”).

  It is an object of the present invention to prevent heat exchanger contamination with hard solid deposits. These solid deposits increase the pressure drop in the heat exchanger, cause significant cleaning costs, and in the worst case can even force an undesired short-term shutdown of the power plant.

  Power plants are usually used to reheat the flue gas downstream of the flue gas purifier in order to discharge the flue gas, residual sulfuric acid and fine dust contained in the flue gas as high as possible into the atmosphere. Equipped with equipment. Without this reheating, usually condensed water is already formed in the chimney. This condensed water usually occurs at or near the chimney wall and then aggregates to form large droplets. Furthermore, the large wash water droplets resulting from the cleaning of the drop separator of the flue gas purification device are also carried into the chimney with the flue gas and then discharged from the chimney. When the flue gas was reheated, the droplets and wash water droplets would have been evaporated in the heat exchanger. Then, the droplets (large condensed water droplets and large washing water droplets) are discharged from the chimney and scattered in the immediate surrounding environment.

  This so-called stack rain is of course acidic (sulfuric acid as a component), and due to corrosion, vehicles (paint damage and corrosion), buildings (decomposition of concrete and building materials), (industrial and personal) severe damage to facilities, plants and gardens May cause damage (acid rain). This must of course be avoided, especially in residential areas. It is conceivable that there will be constant conflicts with local residents who have to watch the private cars, houses and business facilities be destroyed by acid rain.

  This problem is avoided by avoiding the formation of condensed water by reheating the flue gas and by condensing the droplets for the first time outside the chimney by reheating. The flue gas is heated up and the condensate remains small initially and then evaporates in the ambient air before reaching the ground.

  For reheating, so-called Jungstrom heat exchangers (rotational regenerative heat exchangers) have been used for several decades. Jungstrom heat exchangers consist of a maximum number of heat exchanger surfaces, which initially absorb heat in the hot raw gas stream upstream of the flue gas purifier ( And the flue gas is cooled), and then in half-turn to supply heat again to the clean gas coming from the flue gas purifier in countercurrent. The heat exchanger surface absorbs and stores heat from the hot raw gas stream and then pivots further into the counterflow before supplying the stored heat to the countercurrent again.

  This regenerative heat exchanger has the following disadvantages, among others.

  During the raw gas heating, this heat exchanger absorbs dust components in addition to heat. Furthermore, regenerative heat exchangers are not tight and leaky, and hot raw gas can leak into a clean, cool clean gas stream through the leak. Based on these two actions, a predetermined amount of dust components that would have been separated in the flue gas purifier are brought into the flue gas stream to increase the dust load, and downstream of the flue gas purifier. The clean gas is still dust loaded.

  This is of course not desirable and power plant dust emissions should be kept to a minimum. Therefore, contamination of the clean gas with fine dust through leakage in such a regenerative heat exchanger is undesirable.

  Therefore, the concept of a heat exchanger that does not leak has been developed. Such a heat exchanger may be formed as a gas / gas-heat exchanger and may have a tube system through which raw gas flows and clean gas flows outside. However, the heat exchanger may also be formed as a gas / liquid-heat exchanger. In the case of a gas / liquid-heat exchanger, the two gas streams are separated by one liquid circuit, which carries the heat from the raw gas to the clean gas. The flue gas flows through a tubular or plate heat exchanger with liquid on one side and carrier liquid on the other side. The hot raw gas supplies its heat to the coolant. This liquid is then guided to the clean gas side, where heat is again returned to the clean gas in a similar tubular or plate heat exchanger.

  Leakage of raw gas and hence fine dust components to the clean gas side cannot occur in both of the configurations of the heat exchanger.

  However, operating experience with these leak-free heat exchangers has been that heat exchangers can be heavily contaminated during operation. Deposits are formed on the surface of the heat exchanger through which the flue gas flows. These deposits consist of gypsum, limestone, fine dust, and other components of flue gas or more precisely residual droplets in this flue gas, and in most cases are strong with the heat exchanger surface. In addition, it has a hard structure and, in addition, partly has a crystal structure. The deposits are formed especially where the flue gas stream enters the surface of the heat exchanger.

  As a result of these deposits, the pressure loss increases and the heat exchange capacity decreases.

  The deposits become increasingly larger over time and increase by entering into the flue gas path through the heat exchanger tubes or plates. Thereby, the passage space for the flue gas is narrowed, the speed is increased, and the pressure loss is increased. Furthermore, the contamination rate (ie deposit formation) increases as the deposit thickness increases. The deposits create vortices in the free passages between each heat exchanger surface, thus acting to cause more liquid to hit and adhere to the heat exchanger surface. The increase in pressure loss may be so rapid that the boiler must be down adjusted or shut off completely. And, a large increase in pressure loss naturally leads to considerable operating costs. The flue gas fan must operate against this pressure loss and therefore consumes significantly more current than under normal clean conditions. This self-consumption reduces the amount of power to be allocated and hence the sales and revenue of the power plant.

  The heat exchange capacity decreases with time and reheating no longer works. The deposits usually do not conduct heat very well and act as an insulating layer between the flue gas and the heat exchanger surface.

  In addition, corrosion often occurs in connection with deposits. The exposed relatively clean heat exchanger surfaces show little or no corrosion, whereas considerable corrosion often occurs under the deposits. The deposits actually act like a protective layer, under which corrosive liquid can act on the heat exchanger surface and corrode the heat exchanger surface.

  Cleaning contaminated heat exchangers is generally difficult. In addition to being extremely hard, the deposits may be firmly bonded to the surface of the heat exchanger member. This bond must be broken by mechanical force, and deposits must be removed by a high pressure cleaning method. This is not only very labor intensive but also leads to damage to the heat exchanger material. This is because the peeling force of the high-pressure washing machine does not remove only the deposits but also completely removes the surface of the heat exchanger. This shortens the life of this relatively expensive heat exchanger.

  Furthermore, this cleaning is extremely time consuming and can be continued for much longer, not just a few hours. A pause to clean the heat exchanger should not normally be used. That is, if the pressure loss is greatly increased before the end of the operation cycle, and the heating due to this is hindered, it is inevitable that the operation is stopped for a relatively long time.

  The cleaning is also very expensive. The parts to be cleaned of the heat exchanger, such as tube bundles or plate bundles, are inaccessible in practice and need to be lifted from their position many times in order to be cleaned. For this reason, a crane having a considerable lifting force is required in this case. Even a clean bundle already has a considerable weight, so as contamination progresses, the bundle becomes heavier. And cleaning of special places requires considerable time and manpower depending on the nature and thickness of the deposit.

  Unfortunately, it is often impossible to remove all deposits. For that purpose, the normal inspection does not have enough time and manpower. Furthermore, the surface of the heat exchanger located inside can only be reached very limitedly. In this case, the remaining deposits remaining in the heat exchanger serve to accelerate the formation of new deposits. Furthermore, cleaning with a high-pressure cleaner roughens the surface of the heat exchanger, which also accelerates the formation of new deposits. The rough surface and residual deposits act to promote or accelerate the deposit. New deposits may deposit more rapidly on these rough or residual deposits than on smooth and clean surfaces.

  Furthermore, the cleaning means causes damage to the heat exchanger. On the one hand, heat exchanger surface delamination and damage may occur, on the other hand, leading to expansion and recombination to other damage in the heat exchanger structure. The life of the heat exchanger is shortened. Experience has shown that a single wash has the effect of significantly shortening life compared to 12 month operation.

  These experiences have led to contemplation on the cleaning device, which has been incorporated. The purpose of these scrubbers is to prevent or delay contamination, and on the one hand to ensure the operation of the power plant during the operating period and on the other hand to reduce operating and cleaning costs.

  The scrubber was initially installed only on the upstream side of the upstream heat exchanger bundle as viewed in the flue gas flow direction. The experience was that in this case, the deposits protruded most vigorously. Initially working with compressed air and steam, it was quickly confirmed that this did not produce the desired effect of extending operating time. Next, it was washed with high-pressure water.

  Cleaning with high pressure could actually greatly reduce the contamination of the upstream bundle. The deposits could not be completely avoided, but they no longer formed vigorously. First, an increase in pressure loss was avoided and heat loss was kept within limits.

  However, there has also been experience that deposits have occurred in the bundles located further downstream of the heat exchanger, i.e. in areas that were previously not affected at all or relatively little. These deposits were produced with a certain delay (relatively long operation time), but this greatly increased the time and cost of cleaning.

  Some power plants also had additional cleaning systems. There was no space for it at another power plant. In the latter power plant, for cost reasons, the passages filled with heat exchangers were formed as closely and compactly as possible.

  However, from that point on, it was recognized that the deposits were only shifted further downstream by another cleaning device toward another heat exchanger bundle, and the damage to the cleaning effort or heat exchanger was further increased. Also settled. Furthermore, multiple cleaning systems lead to significant investment costs and operating costs. Ultimately, each wash naturally results in the immediate cooling of the flue gas, the inflow of liquid into the chimney, and then into the environment. However, this is exactly what should be avoided.

  The recognition that multiple cleaning systems cannot actually perform the desired function has become established. On the one hand, the investment costs and the operating costs increase, and on the other hand, the cleaning means are only limited enough, and on the contrary, the cleaning costs increase when the operation is stopped.

  The description of these malfunctions of the cleaning device is relatively simple. When a droplet contaminated by solids hits a heated or even hot surface, some of the liquid remains on the surface and wets the surface. The liquid is then evaporated by the constantly supplied heat, leaving only solids. This solid matter is combined with the surface of the heat exchanger at the time of evaporation, and penetrates into a minute gap or hole on the surface to fill it. Then, with time, it grows to a very thick and hard deposit.

  When such formation of deposits is reduced by cleaning, cleaning droplets having the same function as the original droplets coming from the flue gas purification device are generated further downstream in the heat exchanger. When the last heat exchanger is also cleaned, the cleaning droplets jump into the passages and chimneys and then scatter to the surrounding environment as stack rain.

  That is, the cleaning action of the cleaning system at one location leads to the contamination action at other locations. The temporary cooling of the flue gas during cleaning or the temporary discharge of the cleaning liquid from the chimney cancels the heating action again, leading to environmental disturbances that would otherwise be avoided by heating. On the contrary, in some cases, problems with supervisory authorities arise. This is because in the above case, it is temporarily impossible to meet the authorities' standard values.

  Therefore, it can be summarized from these experiences that cleaning of the heat exchanger should be avoided. This is because cleaning during operation involves more problems and costs than profits.

  Therefore, it has been considered to arrange a flue gas purification device upstream of the heat exchanger in yet another target direction. This notion that improving the separation can reduce the amount and rate of contaminant formation was quite correct. As a result of this consideration, the flue gas purifier droplet separator was formed in three stages, and in some cases even four stages, and the function of the droplet separator was improved by other equipment-specific means. .

  This has certainly made progress. The amount of deposit decreased and the deposit formation slowed down. The improved droplet separator, on the one hand, passes fewer droplets during operation (improved separation function), on the other hand, contamination of the droplets by solids on average is reduced.

  Triple or even quadruple droplet separators simply have a better separation function than double droplet separators. It is clear that any droplet separator collects only 98% to 99.9% of the relatively large droplets and never 100%. More stages mean a higher degree of separation.

  In this way, the amount of solid matter in the droplets is also reduced. Most of the droplets on the downstream side of the droplet separator are separated from the last droplet separator cleaning process. If this last drop separator is relatively heavily contaminated, the cleaning droplets that peel off will likewise be heavily contaminated with solids. Conversely, if the last drop separator is not contaminated and is very clean, the wash droplets are only slightly contaminated. This means that if you have a three-stage or even a four-stage droplet separator with a high cleaning capacity, the contamination of the last-stage cleaning entrainment is significantly greater than the cleaning entrainment that results from the two-stage droplet separator. It is running low.

In short, the improved separation could significantly reduce deposit formation. This allowed most facilities to operate without interrupting one complete operating cycle. However,
Two problems remained: 1) considerable cleaning effort, and 2) pressure loss that was constantly formed.

  It has been found that the method has reached its limit and no further improvement is possible.

The problem underlying the present invention is therefore to provide an improved method with respect to the problems mentioned above and an apparatus suitable for carrying out the method. The separation concept found for this is:
1. A high separation capacity for large droplets is guaranteed permanently. That is, the separation ability is not reduced by the progress of contamination.
2. Cleaning delamination must be avoided. In the conventional equipment, the cleaning ability against fine dust is doubled by avoiding the cleaning and peeling that caused 60% to 70% of the total liquid peeling.
3. There should be no increase in pressure loss. An increase in pressure loss caused by the progress of deposit formation is avoided,
These three conditions are satisfied.

  There are various droplet separator concepts that can separate droplets from flue gas, one of which is a multilayer droplet separator with various configurations provided in an absorber as one of the prior arts.

  A particularly successful concept is the so-called “roller separator”. Unlike conventional laminate separators, roller separators use tube segments as impingement bodies, and specially formed molded members that are extruded are used for these tube segments.

  It has been found that this roller separator is extremely resistant to dirt and deposits during operation, yet nevertheless provides a relatively acceptable separation capacity for the separation of conventional laminate separators. However, roller separators have generally been used only as coarse separators in the past. This is because the laminate separator is superior to the roller separator when used as a fine separator.

  The roller separator has heretofore been mainly used for cleaning existing droplet separators. In the meantime, we were able to accumulate sufficient experience in these purified facilities to serve as a basis for use in new facilities.

  It is well known that large droplets cause the effect of deposit formation.

  Small droplets never reach the surface. Because the small droplets have a small mass, they avoid the heat exchanger tubes or heat exchanger plates with the flue gas, fly around them and do not collide. The small droplets are then evaporated by the heat supply, and the solids continue to fly as fine dust.

  Medium-sized droplets partially dodge the flow resistance depending on the flight path, or touch only the surface of the heat exchanger and then mostly split into multiple partial droplets that continue to fly with the flue gas. After that, it evaporates.

  Only large droplets hit the hot surface of the heat exchanger without being able to dodge the flow resistance of the heat exchanger tubes or heat exchanger plates based on their mass. There is then a temporary wetting of the small surface area, which subsequently evaporates on the surface, leaving a tightly bonded hard coating.

  A large droplet is a large cleaning droplet that is created and peeled off by the last separator wash, or a ceiling, wall, or another in the flue gas path between the separator and the heat exchanger It is a large condensed water drop that peels from the peeling edge. These condensed water droplets occur because the ambient temperature is significantly lower than the flue gas temperature, so that even if the flue gas passage is well insulated, a considerable temperature difference acts. Sometimes exfoliate accumulates on the wall and agglomerates before it is exfoliated again.

  Condensed water droplets also have a certain solid component. Dust also accumulates on the walls and ceilings of the flue gas passages, and this dust, in the form of dry dust, remains in contact with the wetted surface and partially in contact with the surface as well. And small droplets having a solid component deposited there. If the condensate and the liquid from the deposit are fully deposited, the droplets will flake back into the flue gas and fly towards the heat exchanger.

  It is impossible to prevent these large droplets from reaching the heat exchanger or remove large droplets from the flue gas stream in advance by conventional droplet separators. Conventional separators have the disadvantage that they are arranged in an absorber with a laminate, which promotes the deposition on the laminate and thus also forms deposits until clogged. Furthermore, a considerable amount of condensed water can be generated between the absorber and the heat exchanger depending on the temperature conditions of the surrounding environment.

  In order to take measures against this, in the flue gas purification and reheating method according to the present invention, the hot flue gas flows through the heat exchanger while dissipating heat, and then flows through the flue gas purification device. Then, after passing through the heat exchanger while absorbing heat, and further supplied to the chimney, the flue gas is disposed downstream of the flue gas purification device and upstream of the heat exchanger as viewed in the flow direction. Guided through an additional liquid separator.

  That is, due to the additional liquid separator being relatively close to the heat exchanger, condensed water droplets are formed between the liquid separator and the heat exchanger, and the condensed water droplets are then formed in the heat exchanger. Resulting in contaminating problems.

  Preferably, in the construction means of the method according to the invention, the flue gas flows through the heat exchanger in a substantially horizontal direction while absorbing heat.

  In a particularly preferred refinement of the method according to the invention, the liquid separator has a plurality of elongated three-dimensional impact bodies whose longitudinal extensions are in the direction of the flue gas flow. The size and arrangement of the impact body obliquely or laterally with respect to the longitudinally extending portion of the impact body and the arrangement type are as follows. Thus, the flue gas cannot flow through the liquid separator without changing the flow direction.

  The present invention also relates to a purification and reheating device for flue gas flowing in a predetermined flow direction, the device comprising a heat exchanger having a heat exchanger casing, the heat exchanger being used for reheating. The gas separator is arranged on the upstream side of the heat exchanger as viewed in the flow direction of the flue gas in the heat exchanger casing. By arranging the liquid separator in the heat exchanger casing, on the one hand, the liquid separator is advantageously relatively close to the heat exchanger in order to carry out the method according to the invention. On the other hand, the flow rate of the flue gas flowing through the heat exchanger is relatively low due to the normally relatively large volume of the heat exchanger casing, and thus the flow rate into the liquid separator is also relatively low. This results in an improved separation capability for large droplets.

  Surprisingly, it has been found that a liquid separator having a plurality of impingement bodies is particularly suitable for use in a heat exchanger casing.

  It is very particularly preferred if the impact body is elongated and three-dimensional, preferably for example tubular. Such a liquid separator is also referred to as a “roller separator”. Since this roller separator itself is known to have a relatively poor separator capability, the use of such a roller separator in a heat exchanger casing seems to be meaningless at first glance. It was broken.

  Nevertheless, it is proposed to use a roller separator as a protection means for the heat exchanger. As is well known, the roller separator is a poor separator as compared with the laminated plate separator. This is in contradiction to the current teaching that the last separator must provide the best separation capability.

  Indeed, based on the present invention, the current teaching should be modified. That is, the separation capability must be increased step by step, and clogging occurs with current teachings where all droplet separators are continuously incorporated into the absorber. The current teachings do not take into account that the particular separation capacity causes inevitable cleaning when the gas contains solids, causing greater contamination than if the separation capacity is reduced. Furthermore, the arrangement format is also a problem.

  In other words, the improvement in separation capability in the final stage results in a very small spacing between the separation laminates, so that such a droplet separator is very contaminated and must be washed frequently. Washing causes severe flaking, which causes more emissions than a separator stage with improved washing capacity will filter from the flue gas. In other words, it is inevitable to take one step and take two steps.

  The solution according to the invention thus takes the opposite path. Surprisingly, it has been found from the specific separation capabilities of the entire system that cleaning produces the majority of emissions, especially in heat exchangers, which can lead to nuisance deposits leading to blockages.

  The object of the arrangement according to the invention is therefore to find a solution which eliminates the need to wash the final separation stage at all. In this case, it is considered that the final stage provides a relatively poor separation capacity.

  It has been found that the roller separator remains completely clean without cleaning even during long-term operation or is only slightly contaminated. And this contamination of the roller has little effect on the total amount of delamination from the separator system.

  Furthermore, it has been found that the roller separator is particularly suitable for use as a protective means upstream of the reheat heat exchanger. It can be explained that the roller separator particularly well separates large droplets. As mentioned above, the main role of the last separator is just to collect and separate the separated wash droplets of the upstream separator. As is well known, these cleaning droplets are large to very large droplets.

  Also, the placement of the roller separator in the heat exchanger casing results in a rather low flue gas velocity based on the size of the heat exchanger casing, thereby reducing the drop separator and heat exchanger. It was also confirmed that negative influences such as condensate water were avoided.

  In this case, it has been found that the disadvantage that small droplets generated by the separation stage located on the upstream side cannot be separated is negligible. These small droplets occupy only a relatively small portion of the amount of liquid reaching the roller separator. Depending on the washing frequency, 90% to 99% of the liquid amount is peeled off from the washing process of the separation stage located upstream.

  The liquid separator formed as a roller separator must have at least two layers of mutually offset tubes (or tubular impingements), which completely block the path in the flow direction. That is, they are configured to overlap each other. This ensures that at least the majority of large droplets hit the impactor.

  Preferably, the roller separator has 3 or 4 tube layers. The third and fourth tube layers are particularly significant when the separator is incorporated very close to the heat exchanger. In this case, this third layer and possibly the fourth layer captures the radiant heat of the heat exchanger and prevents the droplets on the collision tube from evaporating after the first tube layer is heated. .

  It is desirable that the separator be installed as close to the heat exchanger as possible. Normally, the flue gas passage is extended upstream of the heat exchanger. This is because generally the flue gas velocity in the heat exchanger must be lower than in the passage. In order for the tube separator to function well, again, the lowest possible flue gas velocity is required. Furthermore, in this case, no condensed water droplets are expected any longer between the separator and the heat exchanger. The radiant heat of the heat exchanger is usually sufficient to keep the passages dry with a maximum spacing of 2.5 m, i.e. to avoid condensed water. However, if the distance to the heat exchanger is less than 0.5 m, it may lead to heating of the tube separator, which is not desirable. This is because, in that case, in the tube separator, there is a possibility that a drying process may occur, which may reduce the function of the tube separator and increase the pressure loss.

  Thus, the distance of the liquid separator from the heat exchanger is preferably 0.5 m to 2.5 m, preferably 1 m to 2 m, particularly preferably about 1.5 m.

  The heat exchanger may particularly preferably be formed as a leak-free, in particular gas / gas-heat exchanger.

  Furthermore, a cleaning system may be provided for cleaning the liquid separator as required, but this cleaning system is preferably operable especially when the apparatus is shut down.

The invention will be further described with reference to the accompanying drawings.
1 is a schematic partial cross-sectional view of a flue gas purification and reheating device having a heat exchanger, a flue gas purification device, and a molded brick (chimney). FIG. 2 is an enlarged schematic view of a part of the heat exchanger of the device according to the invention.

  In the apparatus shown in FIG. 1, hot flue gas (also referred to as “raw gas”) generated from a power plant (not shown) passes through the supply conduit 1 in the flow direction S toward the heat exchanger 2. Flowing.

  The heat exchanger 2 has a heat exchanger casing 3 and a heat exchanger member 4. The heat exchanger member 4 is formed in a tubular shape in the illustrated embodiment, and the hot flue gas flows through it while radiating heat.

  The raw gas cooled at this time is then supplied to the flue gas purification device 6 via the outlet pipe 5. The flue gas purification apparatus 6 has a plurality of droplet separation units 7, and the cooled raw gas is purified by flowing through these droplet separation units 7 from below to above, so-called It becomes clean gas. The flue gas purification device 6 may have a cleaning device for a droplet separation unit (not shown). The cooled clean gas is introduced into the heat exchanger casing 3 via another supply conduit 8. A liquid separator 9 is provided in the heat exchanger casing 3 on the upstream side of the heat exchanger member 4 when viewed in the flow direction. The liquid separator 9 may have a plurality of tubular impingement bodies 10 extending transversely to the gas flow direction S (as can be seen in FIG. 2).

  In the embodiment shown in FIG. 2, three rows 11, 12, and 13 of collision bodies 10 are provided. The impingement bodies 10 are sized and arranged to overlap in the flow direction when viewed in the flow direction projection.

  After flowing through the liquid separator 9, the clean gas flows while absorbing the outer periphery of the heat exchanger member 4.

  Subsequently, the reheated clean gas is supplied to the chimney 15 via another outlet pipe 14.

DESCRIPTION OF SYMBOLS 1 Supply conduit 2 Heat exchanger 3 Heat exchanger casing 4 Heat exchanger member 5 Outlet tube 6 Flue gas purification device 7 Droplet separation unit 8 Supply conduit 9 Liquid separator 10 Colliding body 11, 12, 13 Row 14 Outlet tube 15 Chimney S Flow direction

Claims (10)

A method for purifying and reheating flue gas, in which high-temperature flue gas flows through the heat exchanger (2) while dissipating heat, then flows through the flue gas purification device (6), and then absorbs heat. While flowing through the heat exchanger (2) and then fed to the chimney (15)
The flue gas flows through the liquid separator (9) on the downstream side of the flue gas purification device (6) and the upstream side of the heat exchanger (2) as viewed in the flow direction (S). A method for purifying and reheating flue gas, characterized in that   The method of claim 1, wherein the flue gas flows through the heat exchanger (2) in a substantially horizontal direction while absorbing heat.   The liquid separator (9) has a plurality of elongated three-dimensional collision bodies (10), and the longitudinal extension of these collision bodies (10) is the flow direction of the flue gas ( S) is oriented obliquely or laterally with respect to S), and the size and arrangement of the colliding body (10) obliquely or laterally with respect to the longitudinally extending portion are viewed in the projection view. The collision bodies (10) are set to overlap each other in the flow direction (S) of the flowing flue gas, so that the flue gas can be separated from the liquid without changing the flow direction. 3. A method according to claim 1 or 2, wherein it is no longer possible to flow through the vessel (9). A purification and reheating device for flue gas flowing in a predetermined flow direction (S), comprising a casing (3) and a heat exchanger member provided in the casing (3) (2 ) Is provided,
A liquid separator (9) is arranged in the heat exchanger casing (3) upstream of the heat exchanger member (4) as seen in the flow direction (S) of the flue gas. Flue gas purification and reheating device characterized by the above.   The apparatus of claim 4, wherein the liquid separator (9) comprises a plurality of impingement bodies (10).   6. A device according to claim 5, wherein the impactor (10) is elongated and formed in three dimensions, preferably in the form of a tube for example.   The apparatus according to claim 6, wherein the collision bodies are each formed so as to overlap each other in the flow direction as viewed in a projection view.   The minimum distance of the liquid separator (9) from the heat exchanger member (4) is 0.5m to 2.5m, preferably 1m to 2m, particularly preferably about 1.5m. The apparatus according to any one of 4 to 7.   9. A device according to any one of claims 4 to 8, wherein the heat exchanger (2) is configured as a leak-free gas / gas-heat exchanger.   10. The device according to claim 4, further comprising a cleaning system for cleaning the liquid separator (9) as needed, particularly when the device is stopped.

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