A desulfurization and dewhitening device

Abstract

The invention discloses a desulfurization and dewhitening device. The device sequentially arranges a desulfurization section and an absorption section from bottom to top in a shell of a flue gas purification device, and arranges a liquid storage unit of a specific structure between the desulfurization section and the absorption section, arranges a first spray layer between the absorption section and the top of the shell, and arranges a second spray layer between the flue gas inlet of the desulfurization section and the liquid storage unit. The flue gas enters the absorption section from the desulfurization section and contacts with a concentrated solution or clean water sprayed on the top of the absorption section in countercurrent. In the heating season, the concentrated solution absorbs water in the flue gas and becomes thinner, releases latent heat in the phase change process of precipitating water, heats the flue gas and the salt solution, and the heated solution is collected by the liquid storage unit and heat-exchanged by the first heat exchanger on the first circulation loop. The equilibrium state in the absorption section is flexibly controlled by the amount of heat taken away, and the sensible heat of the original flue gas and the latent heat of the clean flue gas water vapor are deeply recovered and utilized, avoiding the need for a large number of cold sources for flue gas cooling and condensation in the prior art, and greatly saving water resources.

Description

Technical Field

[0001] The invention belongs to the technical field of environmental protection, and in particular relates to a desulfurization and de-whitening device. Background Art

[0002] At present, the mainstream technology for eliminating wet smoke plume is to arrange flue gas condensers, spray towers or add slurry coolers on the slurry circulation slurry pipes after the desulfurization tower, so that the flue gas at the outlet of the desulfurization tower is cooled and moisture is precipitated, and the waste heat of the original flue gas is used to heat the clean flue gas. This technology not only fails to deeply recover the large amount of latent heat of water vapor in the clean flue gas, but also wastes the sensible heat of the original flue gas. At the same time, the condensation of water from the flue gas requires external refrigerant, resulting in a huge waste of energy.

[0003] In order to remove the latent heat of the net flue gas, a large amount of cooling circulating water is needed. The cold source is a problem that the current mainstream technology must face. Especially for areas where the flue gas temperature and humidity content at the outlet of the desulfurization tower are specified, condensation is required not only in winter but also in summer. In summer, the cooling tower of the power plant is often fully loaded and cannot provide an effective cold source. If a new cooling tower is built, it will require additional investment, and good water will be used to replace waste water, which will not achieve the effect of water saving. If a new mechanical ventilation cooling tower is built, the construction cost will be extremely high, which is unaffordable for the power plant.

[0004] Therefore, the current mainstream technology has the above-mentioned problems of waste of energy and water resources, high investment cost, and only investment without returns in eliminating wet smoke plume. Summary of the invention

[0005] Therefore, the technical problem to be solved by the present invention is that the existing technical route for recovering waste heat from flue gas is unable to fully utilize the sensible heat of the original flue gas and the large amount of latent heat of water vapor in the clean flue gas, and at the same time, energy and water resources are wasted, the investment cost is high, and the elimination of colored smoke plumes only results in investment but no return, thus proposing a desulfurization and dewhitening device.

[0006] In order to solve the above technical problems, the technical solutions provided by the present invention are as follows:

[0007] A desulfurization and desulphurization device comprises a flue gas purification device, wherein the flue gas purification device comprises a housing and further comprises:

[0008] The desulfurization section and the absorption section are sequentially arranged in the shell from bottom to top;

[0009] A liquid storage unit is arranged between the desulfurization section and the absorption section and is located in the shell to separate the desulfurization section and the absorption section. The liquid storage unit comprises a liquid collecting bottom plate suitable for being placed in the shell, and a plurality of annular ventilation belts arranged on the liquid collecting bottom plate at intervals along the radial direction of the liquid collecting bottom plate, and the flue gas is suitable for entering the absorption section from the desulfurization section through the annular ventilation belts; a liquid storage space for receiving the sprayed absorption liquid is provided between adjacent annular ventilation belts and / or between the annular ventilation belts and the inner wall of the shell;

[0010] A first spray layer is provided between the absorption section and the top of the shell and is located inside the shell. The liquid inlet end of the first circulation loop is connected to the liquid storage unit, and the liquid outlet end is connected to the first spray layer. A first heat exchanger is provided on the first circulation loop to cool the absorption liquid in the liquid storage unit and then send it to the first spray layer to spray the rising flue gas.

[0011] The second spray layer is arranged between the flue gas inlet of the desulfurization section and the liquid storage unit, and is located inside the shell. The liquid inlet end of the second circulation loop is connected to the bottom of the shell, and the liquid outlet end is connected to the second spray layer to deliver the desulfurization liquid in the bottom of the shell into the second spray layer and spray the rising flue gas.

[0012] Furthermore, an annular air passage is arranged in the annular ventilation belt, and the annular air passage extends to the absorption section, and the flue gas enters the absorption section from the desulfurization section through the annular air passage, and an annular umbrella cap is arranged directly above the flue gas outlet of the annular air passage to prevent the absorption liquid from being directly sprayed into the annular air passage, and there is a gap suitable for flue gas circulation between the annular umbrella cap and the flue gas outlet of the annular air passage;

[0013] It also includes a plurality of absorption liquid flow channels which penetrate the annular ventilation belt along the radial direction of the liquid collecting bottom plate so as to guide the sprayed absorption liquid to the outside through the absorption liquid flow channels.

[0014] Furthermore, it also includes a liquid storage device, which is arranged on the first circulation loop, so that the absorption liquid in the absorption section is stored in the liquid storage device in the non-heating season; in the heating season, the absorption liquid in the liquid storage device is sent to the absorption section.

[0015] In order to reduce the load on the tower, the absorption section does not have a liquid storage tank in the tower. The absorption liquid is introduced into the absorption liquid storage tank outside the tower through the liquid receiving tray, thereby reducing the load of the entire tower. The absorption section can use the absorption liquid for heat and water recovery throughout the year; it can also use the absorption liquid for heat and water recovery during the heating season, and use clean water spraying in the non-heating season to condense the flue gas and precipitate water to achieve wet smoke plume elimination.

[0016] Furthermore, it also includes a third circulation loop, whose liquid inlet end is connected to the liquid storage device, and whose liquid outlet end is connected to the first spray layer. The third circulation loop is provided with a solution filtering and tempering system and a heat exchange device.

[0017] The fourth circulation loop has a liquid inlet end connected to the liquid storage device and a liquid outlet end connected to the first spray layer. A fourth heat exchanger and a regeneration system are sequentially arranged on the fourth circulation loop.

[0018] Further, the regeneration system comprises a flash tank, wherein a dilute solution inlet is arranged in the middle, a steam outlet is arranged in the upper part, and a concentrated solution outlet is arranged in the lower part, a fifth heat exchanger is connected with the dilute solution inlet, and the concentrated solution outlet is connected with the fourth heat exchanger, so that the absorption liquid after being sprayed with flue gas enters the flash tank for regeneration, and comes out from the concentrated solution outlet and enters the fourth heat exchanger for heat exchange with the absorption liquid after being sprayed with flue gas;

[0019] The compressor and the saturator, the steam outlet, the compressor, the saturator and the fifth heat exchanger are connected in sequence, so that in the non-heating season, the absorption liquid after the flue gas is sprayed is heat exchanged with the secondary steam in the fifth heat exchanger and then enters the flash tank.

[0020] Furthermore, it also includes a fifth circulation loop, whose liquid inlet end is connected to the liquid storage unit, and the liquid outlet end is connected to the first spray layer. The fifth circulation loop is provided with a water storage device and a refrigeration device, so that in the non-heating season, the water in the water storage device is sent to the refrigeration device for cooling, and then sent to the first spray layer for circulating spraying of flue gas; in the heating season, the water in the liquid storage unit is stored in the water storage device.

[0021] Furthermore, it also includes a second heat exchanger and a third heat exchanger, wherein the first heat exchanger, the second heat exchanger and the third heat exchanger are sequentially connected, so that water from the heating network or condensate from the low-temperature heater passes through the first heat exchanger, the second heat exchanger and the third heat exchanger in sequence, and exchanges heat with the substances entering the corresponding heat exchangers;

[0022] The fifth heat exchanger is connected to the second heat exchanger and / or the third heat exchanger, so that the exhaust condensate of the fifth heat exchanger is sent to the second heat exchanger and / or the third heat exchanger for heat exchange and then returns to the boiler feed water, and the secondary steam condensate of the fifth heat exchanger is sent to the third heat exchanger and / or the second heat exchanger for heat exchange and then used as process make-up water;

[0023] The steam outlet is also communicated with the third heat exchanger so as to send the secondary steam into the third heat exchanger for heat exchange.

[0024] Furthermore, it also includes a dust removal device and an economizer which are connected in sequence, and the economizer is connected to the flue gas inlet of the desulfurization section so that the flue gas passes through the dust removal device and the economizer in sequence and then enters the desulfurization section. The third heat exchanger is connected to the economizer to exchange heat between condensed water and the flue gas from the dust removal device in the economizer.

[0025] Furthermore, it also includes a first demister, which is arranged between the first spray layer and the top of the shell and is located inside the shell;

[0026] The second demister is arranged between the second spray layer and the liquid storage unit and is located inside the shell.

[0027] Furthermore, relative to the liquid collecting bottom plate, the levels of the adjacent umbrella caps may be flush or different;

[0028] The smoke outlet at the top of the shell is communicated with the chimney.

[0029] It should be noted that "spraying to eliminate white smoke" in the present invention refers to recovering the heat in the flue gas and eliminating the white smoke phenomenon by spraying absorption liquid and / or clean water.

[0030] The technical solution of the present invention has the following advantages:

[0031] 1. The desulfurization and dewhitening device provided by the present invention has a desulfurization section and an absorption section arranged in sequence from bottom to top in the shell of the flue gas purification device, and a liquid storage unit is arranged between the desulfurization section and the absorption section, a first spray layer is arranged between the absorption section and the top of the shell, and a second spray layer is arranged between the flue gas inlet of the desulfurization section and the liquid storage unit. In actual working process, the flue gas enters the absorption section from the desulfurization section, and contacts with the concentrated solution (such as concentrated salt solution) or clean water sprayed on the top of the absorption section in countercurrent. In the heating season, the concentrated solution absorbs the water in the flue gas and becomes thinner, and releases latent heat in the phase change process of the precipitated water, heating the flue gas and the salt solution. The heated solution is collected by the liquid storage unit and heat exchanged by the first heat exchanger on the first circulation loop, and the equilibrium state in the absorption section is controlled by taking away the heat. In the non-heating season, in addition to using the concentrated solution, clean water spraying can also be used to cool the flue gas, and the saturated clean flue gas is cooled and water is separated, thereby achieving the water extraction effect. The heated water can be recycled after heat exchange through a refrigeration device. Finally, the sensible heat of the original flue gas and the latent heat of the water vapor in the clean flue gas are deeply recovered and utilized through the above means, avoiding the need for a large number of cold sources for cooling and condensing flue gas in the existing technology, greatly saving water resources. At the same time, the moisture in the clean flue gas is recovered, the system operation cost is reduced, and the problem of eliminating colored plumes and deep water extraction systems in coal-fired power plants or other industries with only investment but no benefits is solved, achieving environmental protection effects such as high efficiency, energy saving and emission reduction, and having a good social and economic impact. At the same time, the desulfurization section and the absorption section are set in the same shell, which greatly simplifies the process flow and reduces the equipment cost; the setting of several annular ventilation belts can make the distribution of flue gas more uniform, improve the mass transfer efficiency of flue gas, increase the efficiency of heat exchange, and significantly improve the efficiency of the system. .

[0032] 2. The desulfurization and dewhitening device provided by the present invention first utilizes the absorption section to significantly reduce the moisture content of the clean flue gas. The steam releases latent heat due to phase change during the absorption by the concentrated solution, so that the dryness and temperature of the clean flue gas can be improved, and the effects of eliminating colored plumes, deep water extraction, reducing the dust content of the clean flue gas and recovering the low-quality latent heat of water vapor in the clean flue gas can be achieved at the same time; then the concentrated solution after absorbing water vapor in the absorption section becomes a dilute solution, a part of the dilute solution is heated by the fourth heat exchanger, and then restored to the original concentration by the regeneration system, and finally returned to the absorption section; the other part is heated by the first heat exchanger to heat the heat exchange medium (such as hot network water), and then returned to the absorption device. The sizes of the two flows are adjusted according to specific requirements, and the Adjusting the flow ratio of the two routes can change the water absorption capacity of the concentrated solution per unit mass; in addition, the dilute solution sent to the regeneration system is converted into a concentrated solution by heat exchange with the saturated steam or steam turbine exhaust generated by the regeneration system and entering the flash tank for flash regeneration. The concentrated solution is returned to the absorption device for recycling. In the heating season, the unit exhaust is used to heat the dilute solution for regeneration; in the non-heating season, the regeneration process uses the saturated steam generated by the secondary steam compression at the top of the regeneration system. The saturated steam that releases latent heat becomes secondary steam condensate, which enters the third heat exchanger again for heat exchange with the hot network water. The cooled condensate can be used as the desulfurization section demister flushing water, the absorption section demister flushing water or as process make-up water, etc., which reduces costs and energy consumption. Avoiding the use of power plant steam for regeneration can effectively reduce steam consumption.

[0033] 3. The desulfurization and desulphurization device provided by the present invention uses steam turbine exhaust to extract steam in the heating season of the regeneration system as the regeneration driving heat source. The exhaust condensate is returned to the boiler feed water after heat exchange in the second heat exchanger; in the non-heating season, the secondary steam of the compressor + saturator + flash tower is used to compress the saturated steam produced, and the condensate is used for desulfurization process water replenishment, or clean water spraying is used, or a combination of the two. After the heating network water or low-pressure condensate is heated by heat exchange in the fourth heat exchanger of the absorption device, it is then exchanged with the fifth heat exchanger of the regeneration system to meet the heating network water temperature requirements in the heating season, and then returned to the heat network in the heating season; in the non-heating season, it is removed from the low-pressure or removed from the low-temperature economizer for heat exchange and then removed from the low-pressure, which can be used to heat the low-pressure condensate, so that the power generation capacity of the unit is less affected in the non-heating season. The above method can solve the problem of coal-fired power plants or other industries eliminating wet smoke plumes and deep water extraction systems with no returns. The compressor + saturator + flash tower system can further recover the latent heat of water vapor in the clean flue gas after the desulfurization device, recover the moisture in the clean flue gas, reduce the system operating costs, and achieve efficient energy conservation and emission reduction and other environmental protection effects.

[0034] 4. The desulfurization and desulphurization device provided by the present invention can not only use the sensible heat of the original flue gas to heat the water in the hot network or the condensate of the low-pressure heater, but also recover a large amount of latent heat of water vapor in the flue gas at the same time, and deeply recover the waste heat of the flue gas. Since the flue gas temperature increases during the latent heat recovery process, the water content of the flue gas can be reduced and the flue gas temperature can be increased at the same time, so as to achieve the effect of recovering latent heat to synergistically eliminate colored smoke plumes and reduce the dust content of the flue gas. The device recovers and saves water resources by deeply extracting water. Due to the simple system equipment, it can reduce the system operation pressure drop by about one third compared with the current related technologies, save operating costs, and has a good environmental protection and energy-saving effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0036] Figure 1 It is a layout diagram of a desulfurization and desulphurization device in an embodiment of the present invention;

[0037] Figure 2 is a schematic structural diagram of a flue gas purification device in an embodiment of the present invention;

[0038] Figure 3 is a side view of a structure of a liquid storage unit in an embodiment of the present invention;

[0039] Figure 4 is a top view of a structure of a liquid storage unit in an embodiment of the present invention;

[0040] Figure 5 is a top view of another structure of a liquid storage unit in an embodiment of the present invention;

[0041] Figure 6 is a top view of another structure of a liquid storage unit in an embodiment of the present invention;

[0042] Figure 7 is a top view of another structure of a liquid storage unit in an embodiment of the present invention;

[0043] Figure 8 is a schematic structural diagram of a regeneration system in an embodiment of the present invention;

[0044] The reference numerals are as follows:

[0045] 1-dust removal device; 2-economizer; 3-flue gas purification device; 3-1-absorption section; 3-2-desulfurization section; 3-3-first spray layer; 3-4-second spray layer; 3-5-liquid storage unit; 3-5-1-annular air duct; 3-5-2-annular umbrella cap; 3-5-3-liquid collecting chassis; 3-5-4-outflow pipe; 3-6-first demister; 3-7-second demister; 4-chimney; 5-liquid storage device; 6-solution filtration and conditioning system; 7-water storage device; 8-refrigeration device; 9-sixth heat exchanger; 10-first heat exchanger; 11-second heat exchanger; 12-third heat exchanger; 13-fourth heat exchanger; 14-compressor; 15-saturator; 16-fifth heat exchanger; 17-flash tank; 18-regeneration system. DETAILED DESCRIPTION

[0046] The technical solution of the present invention is described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0048] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0049] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0050] Example 1

[0051] This embodiment provides a desulfurization and de-whitening device, such as Figure 1 and 2As shown, it includes a dust removal device 1, an economizer 2 and a flue gas purification device 3 which are connected in sequence. For example, the dust removal device 1 can be an electrostatic precipitator, and the flue gas purification device 3 includes a housing, and also includes:

[0052] The desulfurization section 3-2 and the absorption section 3-1 are sequentially arranged in the shell from bottom to top; the absorption section 3-1 can be an empty tower section or a packed tower section. When it is a packed tower section, the packing can be a single layer or multiple layers; the top of the absorption section 3-1 is provided with a clean flue gas outlet;

[0053] The liquid storage unit 3-5 is arranged between the desulfurization section 3-2 and the absorption section 3-1, and is located in the shell to separate the desulfurization section 3-2 and the absorption section 3-1. The liquid storage unit 3-5 includes a liquid collecting bottom plate 3-5-3 suitable for being placed in the shell, and a plurality of annular ventilation belts arranged on the liquid collecting bottom plate 3-5-3 at intervals along the radial direction of the liquid collecting bottom plate 3-5-3. The flue gas is suitable for entering the absorption section 3-1 from the desulfurization section 3-2 through the annular ventilation belts; the liquid storage space for receiving the sprayed absorption liquid is between adjacent annular ventilation belts and / or between the annular ventilation belts and the inner wall of the shell; specifically, as Figure 3 , Figure 4 , Figure 5 , Figure 6 and Figure 7 As shown, an annular airway 3-5-1 is arranged in the annular ventilation belt, and the annular airway 3-5-1 extends to the absorption section 3-1, and the flue gas enters the absorption section 3-1 from the desulfurization section 3-2 through the annular airway 3-5-1, and an annular umbrella cap 3-5-2 is arranged directly above the flue gas outlet of the annular airway 3-5-1 to prevent the absorption liquid from being directly sprayed into the airway 3-5-1, and there is a gap suitable for flue gas circulation between the annular umbrella cap 3-5-2 and the flue gas outlet of the annular airway 3-5-1; it also includes a plurality of absorption liquid flow channels, which penetrate the annular ventilation belt along the radial direction of the liquid collecting bottom plate 3-5-3, so as to guide the sprayed absorption liquid to the outside through the absorption liquid flow channels, such as through the external flow pipe 3-5-4 to guide it to the outside; more specifically, as Figure 4 As shown, there are two absorption liquid flow channels, four annular ventilation belts, and a circular ventilation channel in the middle of the liquid collecting bottom plate 3-5-3; Figure 5 As shown, there is one absorption liquid flow channel, four annular ventilation belts, and a circular ventilation channel in the middle of the liquid collecting bottom plate 3-5-3; Figure 6 As shown, there are 4 absorption liquid flow channels, 4 annular ventilation belts, and the middle of the liquid collecting bottom plate 3-5-3 is a circular ventilation channel; Figure 7 As shown, there are 8 absorption liquid flow channels, 4 annular ventilation belts, and the middle of the liquid collecting bottom plate 3-5-3 is a circular ventilation channel;

[0054] In actual operation, the absorption liquid flow channel divides the annular ventilation belt of the liquid collecting bottom plate 3-5-3 into fan-shaped arrangements with equal or unequal spacing. The number of divisions is calculated according to the need for gravity flow. The more divisions there are, the more absorption liquid flow channels there are, and the smaller the absorption liquid gravity flow resistance is. The annular umbrella cap is made and arranged according to the shape and size of the ventilation channel. The horizontal heights of adjacent umbrella caps can be the same or different, such as Figure 3 As described above, the adjacent annular air ducts 3-5-1 are arranged in staggered heights, which can reduce the resistance of the smoke and make the smoke more uniform. The absorption liquid sprayed from the top of the absorption section passes through the annular ventilation belt and the annular umbrella cap on the top of the annular air duct, and collects the absorption liquid into the annular trays between the annular air ducts. The bottoms of the annular trays are connected to each other, and the absorption liquid flows to the outside through gravity and the external flow pipe 3-5-4. This type of liquid storage unit makes the distribution of smoke more uniform, improves the mass transfer efficiency of smoke, increases the efficiency of heat exchange, and can significantly improve the efficiency of the system;

[0055] The first spray layer 3-3 is arranged between the absorption section 3-1 and the top of the shell, and is located inside the shell. The liquid inlet end of the first circulation loop is connected to the liquid storage unit 3-5, and the liquid outlet end is connected to the first spray layer 3-3. The first heat exchanger 10 is arranged on the first circulation loop to cool the absorption liquid in the liquid storage unit 3-5 and then send it to the first spray layer 3-3 to spray the rising flue gas; specifically, Figure 2 As shown, the first spray layer 3-3 is 1-6 layers, the first spray unit is arranged in the first spray layer 3-3, the first spray layer 3-3 is four, divided into four layers, and arranged at intervals; the liquid inlet end of the first circulation loop is connected to the liquid storage space;

[0056] The second spray layer 3-4 is arranged between the flue gas inlet of the desulfurization section 3-2 and the liquid storage unit 3-5, and is located in the shell. The liquid inlet end of the second circulation loop is connected to the bottom of the shell, and the liquid outlet end is connected to the second spray layer 3-4, so as to send the desulfurization liquid in the bottom of the shell into the second spray layer 3-4 and spray the rising flue gas. Specifically, Figure 2 As shown, the second spray layer 3-4 is 1-8 layers, a second spray unit is arranged in the second spray layer 3-4, and the second spray layer 3-4 is 7, divided into 7 layers, and arranged at intervals;

[0057] More specifically, the first spray unit and the second spray unit both include a spray duct and spray nozzles spaced apart thereon, and the first spray unit and the second spray unit are respectively close to the clean flue gas outlets of the absorption section 3-1 and the desulfurization section 3-2, thereby extending the countercurrent contact distance and effectively recovering heat in the flue gas.

[0058] In the above-mentioned desulfurization and dewhitening device, a desulfurization section and an absorption section are arranged in sequence from bottom to top in the shell of the flue gas purification device, and a liquid storage unit is arranged between the desulfurization section and the absorption section, a first spray layer is arranged between the absorption section and the top of the shell, and a second spray layer is arranged between the flue gas inlet of the desulfurization section and the liquid storage unit. In the actual working process, the flue gas enters the absorption section from the desulfurization section and contacts with the concentrated solution (such as concentrated salt solution) or clean water sprayed on the top of the absorption section in countercurrent. In the heating season, the concentrated solution absorbs the moisture in the flue gas and becomes thinner, and releases latent heat in the phase change process of the precipitated moisture, heating the flue gas and the salt solution. The heated solution is collected by the liquid storage unit and heat exchanged by the first heat exchanger on the first circulation loop, and the heat is taken away to control the equilibrium state in the absorption section. In the non-heating season, in addition to using the concentrated solution, clean water spraying can also be used to cool the flue gas, and the saturated clean flue gas is cooled and water is extracted, thereby achieving a water extraction effect. The heated water can be recycled after heat exchange through a refrigeration device. Finally, the sensible heat of the original flue gas and the latent heat of the water vapor in the clean flue gas are deeply recovered and utilized through the above means, avoiding the need for a large number of cold sources for flue gas cooling and condensation in the existing technology, greatly saving water resources. At the same time, the moisture in the clean flue gas is recovered, the system operation cost is reduced, and the problem of eliminating colored plumes and deep water extraction systems in coal-fired power plants or other industries with only investment but no benefits is solved, achieving environmental protection effects such as efficient energy saving and emission reduction, and having a good social and economic impact. At the same time, the desulfurization section and the absorption section are set in the same shell, which greatly simplifies the process flow and reduces the equipment cost.

[0059] Furthermore, it also includes a liquid storage device 5, which is arranged on the first circulation loop, so that the absorption liquid in the absorption section 3-1 is stored in the liquid storage device 5 in the non-heating season; in the heating season, the absorption liquid in the liquid storage device 5 is sent to the absorption section 3-1.

[0060] Furthermore, a third circulation loop is included, the liquid inlet end of which is connected to the liquid storage device 5, and the liquid outlet end is connected to the first spray layer 3-3. A solution filtering and conditioning system 6 and a heat exchange device are arranged on the third circulation loop; specifically, the heat exchange device can be a first heat exchanger 10; the absorption liquid is filtered and conditioned by the solution filtering and conditioning system 6; specifically, the solution filtering and conditioning system 6 is composed of a cyclone + a filter connected in sequence;

[0061] The fourth circulation loop has a liquid inlet connected to the liquid storage device 5 and a liquid outlet connected to the first spray layer 3-3. The fourth heat exchanger 13 and the regeneration system 18 are sequentially arranged on the fourth circulation loop; specifically, Figure 8As shown, the regeneration system 18 includes a flash tank 17, wherein a dilute solution inlet is arranged in the middle, a steam outlet is arranged in the upper part, and a concentrated solution outlet is arranged in the lower part, the fifth heat exchanger 16 is connected with the dilute solution inlet, and the concentrated solution outlet is connected with the fourth heat exchanger 13, so that the absorption liquid after spraying flue gas enters the flash tank 17 for regeneration, and comes out from the concentrated solution outlet, enters the fourth heat exchanger 13 for heat exchange with the absorption liquid after spraying flue gas; the compressor 14 and the saturator 15, the steam outlet, the compressor 14, the saturator 15 and the fifth heat exchanger 16 are connected in sequence, so that in the non-heating season, the absorption liquid after spraying flue gas and the secondary steam are heat exchanged in the fifth heat exchanger 16 and then enters the flash tank 17; the fourth heat exchanger 13 can be a plate heat exchanger.

[0062] In addition, if Figure 2 As shown, the absorption section 3-1 is provided with an external circulation and an internal circulation, the external circulation is 1-2 layers, and the internal circulation is 2-4 layers. The specific number of settings is determined according to the flue gas volume of the project. Each circulation layer is provided with a heat exchanger or a circulation pump separately, and the moving equipment is backed up according to relevant specifications. The external circulation is responsible for system regeneration, and the internal circulation is responsible for the balance state of the absorption system. Specifically, the absorption liquid in the liquid storage device 5 is divided into three paths, namely the first circulation loop, the second circulation loop and the third circulation loop. In the first circulation loop, the absorption liquid after spraying returns to the top of the absorption section 3-1 after heat exchange in the first heat exchanger 10 to form a small cycle; in the second circulation loop, the absorption liquid after spraying enters the regeneration system 18 after being heated by the fourth heat exchanger 13; in the third circulation loop, the absorption liquid after spraying enters the solution filtration and conditioning system 6. On the one hand, the solid particles accumulated in the solution in the absorption section and the generated crystalline salts (sulfates, carbonates, etc.) can be removed by the cyclone + filtration device, so that the pollutants and impurities in the absorption section solution are controlled to a certain extent; on the other hand, calcium-based salts are added to adjust the pH of the solution, maintain the absorption capacity of the solution, and reduce the corrosiveness of the solution. The absorption liquid enters from the top of the absorption section, and through uniform spraying and counter-convection with the flue gas entering from the bottom of the absorption section, the water vapor in the flue gas is absorbed by the concentrated solution, and a spare layer can be set for the spray layer to improve the reliability of the absorption section. The water absorption capacity of unit mass of salt solution can be controlled by adjusting the amount of circulating solution in the absorption section. The concentration of the dilute solution after absorption is reduced by 1%-10% relative to the concentrated solution. The ratio of the internal circulation volume to the regeneration circulation volume can be 1:1-10:1.

[0063] In the heating season, the regeneration system uses steam turbine exhaust as the regeneration drive heat source; in the non-heating season, a regeneration system (compressor + saturator + plate heat exchanger + flash tank) is used, or a clean water spray system, or a combination of a regeneration system and a clean water spray system is used. The flue gas enters from the bottom of the desulfurization section for desulfurization and then enters the bottom of the absorption section from the desulfurization section gas cap. Specifically, the gas cap can be an umbrella cap 3-5-2. The clean flue gas after desulfurization enters the absorption section and countercurrents with the concentrated salt solution sprayed at the top of the absorption section. The concentrated salt solution at the top of the absorption section absorbs the water in the flue gas and becomes thinner. The latent heat is released during the phase change process of the precipitated water, heating the flue gas and the salt solution. The heated solution is drawn out through the liquid collecting bottom plate at the bottom of the upper section and enters the liquid storage device.

[0064] The absorbed liquid after spraying then enters the evaporator for partial gasification, and finally enters the flash tank to flash out the absorbed water. The driving heat source uses the steam of the pumping unit in the heating season, and MVR (compressor + saturator + plate heat exchanger + flash tank) is used in the non-heating season to improve the quality of the secondary steam. According to the temperature of the primary steam condensate and the secondary steam, the primary steam condensate can enter the third heat exchanger or the second heat exchanger for heat exchange, and the primary steam condensate after heat exchange returns to the boiler; the evaporated secondary steam can enter the second heat exchanger or the third heat exchanger for heat exchange, and the secondary condensate after heat exchange is used for water replenishment in the desulfurization process. The concentrated solution coming out of the bottom of the flash tank enters the fourth heat exchanger for heat exchange with the dilute solution and is then sent to the top of the absorption section for circulation absorption. The dilute solution after being heated by the concentrated solution enters the fifth heat exchanger to continue to heat up (the heat source is the steam from the extraction unit in the heating season), and then flashes in the flash tank to increase the heating area by recovering the latent heat of the net flue gas. In the heating season, the condensate from the extraction enters the second heat exchanger or the third heat exchanger to exchange heat with the hot network water, and the secondary steam at the top of the flash tank enters the third heat exchanger or the second heat exchanger to raise the hot network water to about 85°C for heating.

[0065] Example 2

[0066] This embodiment provides a desulfurization and desulphurization device, which, based on the above embodiment 1, further includes a fifth circulation loop, whose liquid inlet end is connected to the liquid storage unit 3-5, and whose liquid outlet end is connected to the first spray layer 3-3. The fifth circulation loop is provided with a water storage device 7 and a refrigeration device 8, so that in the non-heating season, the water in the water storage device 7 is sent to the refrigeration device 8 for refrigeration, and then sent to the first spray layer 3-3 for circulating spraying of flue gas; in the heating season, the water in the liquid storage unit 3-5 is stored in the water storage device 7; in this embodiment, the refrigeration device 8 is a cooling tower or a closed mechanical ventilation cooling tower; the water storage device 7 is a clean water tank;

[0067] In the non-heating season, the absorption section can also use clean water spraying to cool the flue gas, and the saturated clean flue gas will cool down and precipitate water, thereby achieving the effect of water extraction. In the non-heating season, the gravity height difference is used to completely discharge the absorption liquid at the bottom of the absorption section into the liquid storage device, the absorption section solution bypass is closed, the clean water tank bypass is opened, and the circulating water pump is used to send the clean water at the bottom of the absorption section to the top of the tower for spraying. After the spray water and the flue gas transfer mass and heat in the absorption section, the temperature rises, and the condensed water enters the circulating cooling water. The cooling water at the bottom of the absorption section that has been heated up is sent to the refrigeration device for cooling. The refrigeration device uses a cooling tower or a closed mechanical ventilation cooling tower. The heated circulating cooling water can be directly sent to the cooling tower or the closed mechanical ventilation cooling tower. The water collected in the cooling tower is carried away by the air, while the closed mechanical ventilation cooling tower cannot evaporate the excess condensed water. Excess water will be removed before entering the closed mechanical ventilation cooling tower, and the remaining water will enter the mechanical ventilation cooling tower; The second method: The heated circulating cooling water can be heat exchanged through the plate heat exchanger of the regeneration system. The refrigerant of the plate heat exchanger comes from the cooling water of the cooling tower or the closed mechanical ventilation cooling tower. Similarly, the heated bottom circulating cooling water also needs to remove condensed water before entering the plate exchanger. In the non-heating season, the regeneration system is cut off, and the circulating cooling water produced by the cooling tower or the closed mechanical ventilation cooling tower is sprayed and cooled in the absorption section to achieve the environmental protection requirements of eliminating wet smoke plumes in the non-heating season of the power plant;

[0068] When there is no heating demand in the non-heating season, if flue gas water extraction is still required, the regeneration system switches to the MVR operation mode, and the secondary steam is discharged from the top of the flash tank into the compressor, and becomes superheated steam after pressurization and temperature increase, and becomes saturated steam after spraying, which is used as the flash tank driving heat source. After releasing latent heat, it becomes condensed water, and the condensed water exchanges heat with the hot network water again, and the hot network water (low-pressure condensed water) can be heated to about 60°C. The cooled condensed water can be used for demister flushing water in the desulfurization section or absorption section. This operation mode can make the energy consumption of air extraction and recovery in the non-heating season almost offset each other, and has no negative impact on the power generation capacity of the unit.

[0069] Example 3

[0070] This embodiment provides a desulfurization and dewhitening device, which, based on the above embodiment 1 or 2, further includes a second heat exchanger 11 and a third heat exchanger 12. The first heat exchanger 10, the second heat exchanger 11 and the third heat exchanger 12 are sequentially connected, so that the water from the heating network or the condensate from the low-temperature heater passes through the first heat exchanger 10, the second heat exchanger 11 and the third heat exchanger 12 in sequence, and exchanges heat with the substances entering the corresponding heat exchangers.

[0071] The fifth heat exchanger 16 is connected to the second heat exchanger 11 and / or the third heat exchanger 12 so that the exhaust condensate of the fifth heat exchanger 16 is sent to the second heat exchanger 11 and / or the third heat exchanger 12 for heat exchange and then returned to the boiler feed water, and the secondary steam condensate of the fifth heat exchanger 16 is sent to the third heat exchanger 12 and / or the second heat exchanger 11 for heat exchange and then used as process make-up water; the steam outlet is also connected to the third heat exchanger 12 so that the secondary steam is sent to the third heat exchanger 12 for heat exchange.

[0072] Example 4

[0073] This embodiment provides a desulfurization and desulphurization device. On the basis of the above-mentioned embodiments 1, 2 or 3, the economizer 2 is connected with the flue gas inlet of the desulfurization section 3-2, so that the flue gas passes through the dust removal device 1 and the economizer 2 in sequence and then enters the desulfurization section 3-2. The third heat exchanger 12 is connected with the economizer 2 to exchange heat between condensed water and the flue gas from the dust removal device 1 in the economizer 2.

[0074] It also includes a sixth heat exchanger 9, which is in communication with the fourth heat exchanger 13 and is used to heat the concentrated solution after heat exchange in the fourth heat exchanger 13 again in the sixth heat exchanger 9;

[0075] The smoke outlet at the top of the shell is communicated with the chimney 4 .

[0076] Example 5

[0077] This embodiment provides a desulfurization and dewhitening device, which, based on the above-mentioned embodiment 1, 2, 3 or 4, further includes a first demister 3-6, which is arranged between the first spray layer 3-3 and the top of the shell, and is located inside the shell;

[0078] The second demister 3-7 is disposed between the second spray layer 3-4 and the liquid storage unit 3-5 and is located in the housing. Figure 2 As shown, a spray layer may also be provided at the corresponding second demister 3-7 to flush the corresponding first demister 3-6 and the second demister 3-7.

[0079] In addition, the specific working principle of the above device is as follows:

[0080] like Figure 2The absorption section is arranged with 2-6 layers of spray layers according to the flue gas volume. Generally, there are 2 layers of external circulation and 3 layers of internal circulation. The concentrated salt solution at the top of the absorption section absorbs the moisture in the flue gas and becomes thinner. The latent heat is released during the phase change of the precipitated moisture to heat the flue gas and the salt solution. The heated solution is exchanged with the plate heat exchanger on each branch of the internal circulation. The equilibrium state in the absorption section is controlled by the amount of heat taken away. The external circulation is generally one in use and one in reserve. The external circulation can carry the moisture absorbed by the absorption section to the regeneration system for regeneration. The flue gas enters the bottom of the desulfurization section for desulfurization, and then enters the bottom of the absorption section from the gas cap of the desulfurization section. The gas cap can be rectangular or circular, and countercurrently with the concentrated salt solution sprayed on the top of the absorption section. The concentrated salt solution at the top of the absorption section absorbs moisture in the flue gas and becomes thinner. The latent heat is released during the phase change of the precipitated moisture, heating the flue gas and the salt solution. The heated solution is led out through the liquid collecting bottom plate at the bottom of the upper section and enters the liquid storage device. The solution in the liquid storage device is divided into three parts. The first part is sent to the heat network heat exchanger through a circulating pump to exchange heat with the heat network water or low-pressure condensate. The dilute solution after heat exchange is recycled to the top of the absorption section for spraying to form an internal circulation; the second part enters the solution conditioning tank for conditioning, and is then sent by the conditioning pump to mix with the dilute solution of the circulating pump and enter the heat network heat exchanger; the third part is sent from the dilute solution heat exchanger to the dilute concentrated solution heat exchanger for heat exchange with the concentrated solution, and then enters the saturator for partial gasification, and finally enters the flash tank to flash out the absorbed moisture. The driving heat source uses the steam of the extraction unit in the heating season, and MVR is used in the non-heating season to improve the quality of secondary steam. According to the temperature of the primary steam condensate and the secondary steam, the primary steam condensate can enter the third or second stage heat exchanger of the heating network for heat exchange, and the primary steam condensate after heat exchange returns to the boiler; the secondary steam can enter the second or third stage heat exchanger of the heating network for heat exchange, and the secondary condensate after heat exchange is used for water replenishment in the desulfurization process. The concentrated solution from the bottom of the flash tank enters the dilute concentrated solution heat exchanger and exchanges heat with the dilute solution before being sent to the top of the absorption section for circulation absorption. The dilute solution heated by the concentrated solution enters the plate heat exchanger to continue to heat up (the heat source is the steam of the extraction unit in the heating season), and then flashes in the flash tank to increase the heating area by recovering the latent heat of the net flue gas. In the heating season, the extraction condensate enters the second stage heat exchanger or the third stage heat exchanger of the heating network for heat exchange with the heating network water, and the secondary steam at the top of the flash tank enters the third stage heat exchanger or the second stage heat exchanger of the heating network to raise the heating network water to about 85℃ for heating.

[0081] When there is no heating demand in the non-heating season, if flue gas water extraction is still required, the regeneration system switches to the MVR operation mode, and the secondary steam is discharged from the top of the regenerator into the compressor, and becomes superheated steam after pressure and temperature increase, and becomes saturated steam after spraying, which is used as the regenerator driving heat source. After releasing latent heat, it becomes condensed water, and the condensed water exchanges heat with the hot network water again, and the hot network water (low-pressure condensed water) can be heated to about 60°C. The cooled condensed water can be used for flushing water of the desulfurization tower demister, etc. This operation mode can make the non-heating season exhaust energy consumption and recovery energy consumption almost offset each other, and has no negative impact on the power generation capacity of the unit.

[0082] In the non-heating season, the absorption section can use clean water spraying to cool the flue gas, and the saturated clean flue gas can be cooled and separated to achieve the water extraction effect. For the absorption section, in the non-heating season, the height difference gravity is used to completely discharge the absorption section at the bottom of the absorption section into the liquid storage device or water storage device, the absorption section solution bypass is closed, the clean water tank bypass is opened, and the circulating water pump is used to send the clean water at the bottom of the absorption section to the top of the tower for spraying. After the spray water and the flue gas transfer mass and heat in the absorption section, the temperature rises, and the condensed water enters the circulating cooling water. The cooling water at the bottom of the absorption section that has been heated up is sent to the refrigeration device for cooling. The refrigeration device adopts a cooling tower or a closed mechanical ventilation cooling tower. The heated circulating cooling water can be directly sent to the cooling tower or the closed mechanical ventilation cooling tower. The water collected in the cooling tower is taken away by the air, and the closed mechanical ventilation cooling tower cannot evaporate the excess condensed water. The excess water will be removed before entering the closed mechanical ventilation cooling tower, and the remaining water will enter the mechanical ventilation cooling tower; the second method: the heated circulating cooling water can be heat-exchanged through the plate heat exchanger of the regeneration system. The refrigerant of the plate heat exchanger comes from the cooling water of the cooling tower or the closed mechanical ventilation cooling tower. Similarly, the heated bottom circulating cooling water also needs to remove condensed water before entering the plate heat exchanger.

[0083] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A desulfurization and desulphurization device, comprising a flue gas purification device, wherein the flue gas purification device comprises a housing, characterized in that: Also includes, The desulfurization section and the absorption section are sequentially arranged in the shell from bottom to top; the absorption section is a packed tower section, and the packing can be single-layer or multi-layer; A liquid storage unit is arranged between the desulfurization section and the absorption section, and is located in the shell to separate the desulfurization section and the absorption section. The liquid storage unit includes a liquid collecting bottom plate suitable for being placed in the shell, and a plurality of annular ventilation belts arranged on the liquid collecting bottom plate at intervals along the radial direction of the liquid collecting bottom plate, and the flue gas is suitable for entering the absorption section from the desulfurization section through the annular ventilation belts; a liquid storage space for receiving the sprayed absorption liquid is provided between adjacent annular ventilation belts and / or between the annular ventilation belts and the inner wall of the shell; an annular airway is provided in the annular ventilation belt, and the annular airway extends to the absorption section, and the flue gas enters the absorption section from the desulfurization section through the annular airway; an annular umbrella cap for preventing the absorption liquid from being directly sprayed into the annular airway is provided directly above the flue gas outlet of the annular airway, and a gap suitable for flue gas circulation exists between the annular umbrella cap and the flue gas outlet of the annular airway; A plurality of absorption liquid flow channels penetrate the annular ventilation belt along the radial direction of the liquid collecting bottom plate, so as to guide the sprayed absorption liquid to the outside through the absorption liquid flow channels; A first spray layer is provided between the absorption section and the top of the shell and is located inside the shell. The liquid inlet end of the first circulation loop is connected to the liquid storage unit, and the liquid outlet end is connected to the first spray layer. A first heat exchanger is provided on the first circulation loop to cool the absorption liquid in the liquid storage unit and then send it to the first spray layer to spray the rising flue gas. The second spray layer is arranged between the flue gas inlet of the desulfurization section and the liquid storage unit and is located in the shell. The liquid inlet end of the second circulation loop is connected to the bottom of the shell, and the liquid outlet end is connected to the second spray layer, so as to send the desulfurization liquid in the bottom of the shell into the second spray layer and spray the rising flue gas; A liquid storage device is arranged on the first circulation loop, so that the absorption liquid in the absorption section is stored in the liquid storage device in the non-heating season; and the absorption liquid in the liquid storage device is sent to the absorption section in the heating season; A third circulation loop, whose liquid inlet end is connected to the liquid storage device, and whose liquid outlet end is connected to the first spray layer, and the third circulation loop is provided with a solution filtering and conditioning system and a heat exchange device; a fourth circulation loop, whose liquid inlet end is connected to the liquid storage device, and whose liquid outlet end is connected to the first spray layer, and a fourth heat exchanger and a regeneration system are sequentially arranged on the fourth circulation loop; The regeneration system comprises A flash tank, wherein a dilute solution inlet is arranged in the middle, a steam outlet is arranged in the upper part, and a concentrated solution outlet is arranged in the lower part, a fifth heat exchanger is communicated with the dilute solution inlet, and the concentrated solution outlet is communicated with the fourth heat exchanger, so that the absorption liquid after being sprayed with flue gas enters the flash tank for regeneration, and comes out from the concentrated solution outlet and enters the fourth heat exchanger for heat exchange with the absorption liquid after being sprayed with flue gas; The compressor and the saturator, the steam outlet, the compressor, the saturator and the fifth heat exchanger are connected in sequence, so that in the non-heating season, the absorption liquid after the flue gas is sprayed is heat exchanged with the secondary steam in the fifth heat exchanger and then enters the flash tank.

2. The device according to claim 1, characterized in that Also includes, The fifth circulation loop has a liquid inlet end connected to the liquid storage unit, and a liquid outlet end connected to the first spray layer. The fifth circulation loop is provided with a water storage device and a refrigeration device so that in the non-heating season, the water in the water storage device is sent to the refrigeration device for refrigeration, and then sent to the first spray layer for circulating spraying of flue gas; in the heating season, the water in the liquid storage unit is stored in the water storage device.

3. The device according to claim 2, characterized in that Also includes, The second heat exchanger and the third heat exchanger, wherein the first heat exchanger, the second heat exchanger and the third heat exchanger are connected in sequence, so that the water from the heating network or the condensate from the low-temperature heater passes through the first heat exchanger, the second heat exchanger and the third heat exchanger in sequence and exchanges heat with the substances entering the corresponding heat exchangers; The fifth heat exchanger is connected to the second heat exchanger and / or the third heat exchanger, so that the exhaust condensate of the fifth heat exchanger is sent to the second heat exchanger and / or the third heat exchanger for heat exchange and then returns to the boiler feed water, and the secondary steam condensate of the fifth heat exchanger is sent to the third heat exchanger and / or the second heat exchanger for heat exchange and then used as process make-up water; The steam outlet is also communicated with the third heat exchanger so as to send the secondary steam into the third heat exchanger for heat exchange.

4. The device according to claim 3, characterized in that It also includes a dust removal device and an economizer which are connected in sequence. The economizer is connected to the flue gas inlet of the desulfurization section so that the flue gas passes through the dust removal device and the economizer in sequence and then enters the desulfurization section. The third heat exchanger is connected to the economizer to exchange heat between condensed water and the flue gas from the dust removal device in the economizer.

5. The device according to claim 1, characterized in that Also includes, a first demister, disposed between the first spray layer and the top of the shell, and located inside the shell; The second demister is arranged between the second spray layer and the liquid storage unit and is located inside the shell.

6. The device according to any one of claims 1 to 5, characterized in that Relative to the liquid collecting bottom plate, the adjacent umbrella caps have different horizontal heights; The smoke outlet at the top of the shell is communicated with the chimney.

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