Absorption liquid regeneration device and method for flue gas waste heat recovery

Abstract

The application discloses an absorption liquid regeneration device and method for flue gas waste heat recovery, and belongs to the field of power plant flue gas treatment. The device is divided into a desulfurization slurry area and an absorption liquid regeneration area in the inner cavity. The two areas are only connected at the top. The design can realize the partition flash evaporation of the desulfurization slurry and the absorption liquid without interference, can ensure that the flash evaporation of the desulfurization slurry and the flash evaporation regeneration of the absorption liquid are simultaneously performed by only one set of negative pressure equipment, and can realize the sharing of the negative pressure equipment by the two operations, thereby reducing the number of negative pressure equipment, the equipment investment and the equipment power consumption. The device can effectively improve the water heat recovery rate in the flue gas by the two-stage water heat recovery of the desulfurization slurry flash evaporation and the matched saturated wet flue gas solution absorption. The desulfurization slurry flash evaporation and the dilute solution flash evaporation regeneration are performed in the same flash evaporation device, and the utilization efficiency of the negative pressure equipment is improved. The device has the advantages of simple principle and structure, easy operation and maintenance, high cost performance, and good popularization and application value.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of power plant flue gas treatment, and particularly relates to an absorption liquid regeneration device and method for flue gas waste heat recovery. BACKGROUND

[0002] For a cogeneration unit, waste heat recovery in the recovery system is one of the best ways to increase the heating capacity without expanding the unit size. Currently, power plants usually use the water spraying method to reduce the flue gas to 50-60 DEG C before discharging, and the heat in the flue gas is not recovered, resulting in waste of energy. At the same time, the saturated wet flue gas discharged after spraying still contains part of the heat and a large amount of water vapor, which is easy to form a white smoke plume when discharged into the air; in view of the above problems, power plants usually use some means to recover the flue gas total heat and water, which not only can improve the thermal efficiency of the system, but also can save water resources.

[0003] The desulfurization slurry flash heat extraction technology is a new type of flue gas waste heat recovery technology. The technology utilizes the characteristics that the boiling point of the slurry in the wet flue gas desulfurization process will decrease with the decrease of the environmental pressure, establishes a vacuum phase change environment, makes the desulfurization slurry above the current negative pressure saturation temperature to flash, generates negative pressure steam to carry the latent heat of vaporization to the absorption heat pump to condense and release heat to the low temperature medium, so as to realize the clean and efficient recovery of the waste heat of the desulfurization slurry. The technology can achieve the multiple purposes of energy saving, water saving, improving the desulfurization efficiency and eliminating the visual pollution of the smoke plume, and can simultaneously consider energy saving and emission reduction. However, when the desulfurization slurry is flashed, a vacuum pump is needed to maintain the negative pressure environment, and the system power consumption is large. In the system for recovering the water and heat of the low temperature wet flue gas by using the absorption heat pump, the regeneration of the absorption liquid is generally realized by high temperature evaporation or low temperature flashing, and the energy consumption is also high.

[0004] Therefore, when the desulfurization slurry is flashed and the absorption liquid is regenerated by using the existing device, two negative pressure environments need to be constructed, resulting in large energy consumption and large recovery cost. SUMMARY

[0005] In order to solve the above technical problems, the present application provides an absorption liquid regeneration device and method for flue gas waste heat recovery, which can realize the desulfurization slurry flashing and the absorption liquid regeneration by constructing only one negative pressure environment, thereby reducing the energy consumption and the recovery cost.

[0006] In order to achieve the above purpose, the present application adopts the following technical contents:

[0007] An absorption liquid regeneration device for flue gas waste heat recovery, comprising a shell, a negative pressure device for keeping the inner cavity of the shell in a vacuum condition;

[0008] The inner cavity of the shell is divided into a desulfurization slurry area and an absorption liquid regeneration area, and the two areas are only connected at the top.

[0009] The desulfurization slurry zone is provided with a desulfurization slurry spraying device for spraying desulfurization slurry, and a desulfurization slurry outflow pipe is arranged at the bottom of the desulfurization slurry zone for discharging low-temperature desulfurization slurry.

[0010] The absorption liquid regeneration zone is provided with an absorption liquid spraying device for spraying dilute absorption liquid, and an absorption liquid outflow pipe is arranged at the bottom of the absorption liquid regeneration zone for discharging concentrated absorption liquid.

[0011] The top of the shell is provided with a steam outlet.

[0012] Further, a demister is arranged above the desulfurization slurry zone and the absorption liquid regeneration zone to prevent the mixing of desulfurization slurry and absorption liquid.

[0013] Further, the desulfurization slurry spraying device comprises a desulfurization slurry distribution pipe inserted into the desulfurization slurry zone, and the desulfurization slurry distribution pipe is connected with a first spraying nozzle with a downward spraying port.

[0014] Further, the absorption liquid spraying device comprises an absorption liquid distribution pipe inserted into the absorption liquid regeneration zone, and the absorption liquid distribution pipe is connected with a second spraying nozzle with a downward spraying port.

[0015] Further, the negative pressure device comprises a vacuum pump, and the vacuum pump is in communication with the desulfurization slurry zone or the absorption liquid regeneration zone.

[0016] Further, the inner cavity of the shell is divided into a desulfurization slurry zone and an absorption liquid regeneration zone by a partition plate, the bottom of the partition plate is connected with the shell in a closed manner, and the top of the partition plate forms a gap with the shell.

[0017] Further, the outer wall of the partition plate is coated with a high polymer material.

[0018] Further, the desulfurization slurry outflow pipe is connected with a desulfurization tower.

[0019] Further, the absorption liquid outflow pipe is connected with a hydrothermal recovery tower.

[0020] A working method of an absorption liquid regeneration device for flue gas waste heat recovery, based on the above-mentioned absorption liquid regeneration device for flue gas waste heat recovery, characterized in that it comprises:

[0021] The negative pressure device provides a negative pressure environment, the desulfurization slurry spraying device sprays desulfurization slurry into the desulfurization slurry zone, the absorption liquid spraying device sprays dilute absorption liquid into the absorption liquid regeneration zone, low-temperature desulfurization slurry is discharged through the desulfurization slurry outflow pipe, concentrated absorption liquid is discharged through the absorption liquid outflow pipe, and flash steam is discharged through the steam outlet.

[0022] Compared with the prior art, the present application has the following beneficial effects:

[0023] The device separates the inner cavity into a desulfurization slurry area and an absorption liquid regeneration area, and the two areas are only connected at the top, which can realize the partitioned flashing of the desulfurization slurry and the absorption liquid without interference, can ensure that the flashing of the desulfurization slurry and the flashing regeneration of the absorption liquid are simultaneously performed by only one set of negative pressure equipment, and can reduce the number of negative pressure equipment, that is, reduce the equipment investment and the equipment power consumption; the device can effectively improve the water heat recovery rate in the flue gas through the two-stage water heat recovery of the desulfurization slurry flashing and the saturated wet flue gas solution absorption; the desulfurization slurry flashing and the flashing regeneration of the dilute solution are performed in the same flashing device, the utilization efficiency of the negative pressure equipment is improved, the principle and structure of the device are simple, the device is easy to operate and maintain, the cost performance is high, and the device has good popularization and application value.

[0024] Preferably, a demister is arranged above the desulfurization slurry area and the absorption liquid regeneration area, and the demister can effectively prevent the mixing and cross of the desulfurization slurry and the absorption liquid.

[0025] Preferably, the inner cavity of the shell is separated into the desulfurization slurry area and the absorption liquid regeneration area by a partition plate, and the outer wall of the partition plate is coated with a high polymer material, so that the partitioned flashing of the desulfurization slurry and the absorption liquid is realized without interference.

[0026] The application further provides a working method of the absorption liquid regeneration device for flue gas waste heat recovery, and the method can effectively improve the water heat recovery rate in the flue gas through the two-stage water heat recovery of the desulfurization slurry flashing and the saturated wet flue gas solution absorption based on the absorption liquid regeneration device for flue gas waste heat recovery; the desulfurization slurry flashing and the flashing regeneration of the dilute solution are performed in the same flashing device, the utilization efficiency of the vacuum pump is improved, the number of required vacuum pumps is reduced, and the equipment cost and the power consumption of the vacuum pump are reduced. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 A structural schematic view of the absorption liquid regeneration device for flue gas waste heat recovery is provided for the embodiment of the application;

[0028] Figure 2 A top view of the absorption liquid regeneration device for flue gas waste heat recovery is provided for the embodiment of the application.

[0029] REFERENCE NUMERALS

[0030] Shell-1, first spraying nozzle-2-1, second spraying nozzle-2-2, desulfurization slurry distribution pipe-3, desulfurization slurry outflow pipe-4, steam outlet-5, demister-6, absorption liquid distribution pipe-7, partition plate-8, and absorption liquid outflow pipe-9. DETAILED DESCRIPTION

[0031] In order to make the technical problems solved by the present application, technical solutions and beneficial effects clearer, the following specific embodiments are used to further illustrate the present application. It should be understood that the specific embodiments described herein are only used to explain the present application and not used to limit the present application.

[0032] The present application provides an absorption liquid regeneration device for flue gas waste heat recovery, comprising a shell 1 and a negative pressure device for keeping the inner cavity of the shell 1 in a vacuum condition; the inner cavity of the shell 1 is divided into a desulfurization slurry area and an absorption liquid regeneration area by a partition plate 8, and the two areas are only connected at the top; a desulfurization slurry spraying device for spraying desulfurization slurry is arranged in the desulfurization slurry area, and a desulfurization slurry outflow pipe 4 for discharging low-temperature desulfurization slurry is arranged at the bottom of the desulfurization slurry area; an absorption liquid spraying device for spraying dilute absorption liquid is arranged in the absorption liquid regeneration area, and an absorption liquid outflow pipe 9 for discharging concentrated absorption liquid is arranged at the bottom of the absorption liquid regeneration area; a steam outlet 5 is arranged at the top of the shell 1. The negative pressure device comprises a vacuum pump, which is connected with the desulfurization slurry area or the absorption liquid regeneration area.

[0033] In order to effectively prevent the mixing and cross of the desulfurization slurry and the absorption liquid, a demister 6 for preventing the mixing and cross of the desulfurization slurry and the absorption liquid is arranged at the top of the desulfurization slurry area and the absorption liquid regeneration area.

[0034] The desulfurization slurry spraying device comprises a desulfurization slurry distribution pipe 3 inserted into the desulfurization slurry area, and the desulfurization slurry distribution pipe 3 is connected with a first spraying nozzle 2-1 with a downward spraying port. The absorption liquid spraying device comprises an absorption liquid distribution pipe 7 inserted into the absorption liquid regeneration area, and the absorption liquid distribution pipe 7 is connected with a second spraying nozzle 2-2 with a downward spraying port.

[0035] In order to realize the partition flashing of the desulfurization slurry and the absorption liquid without interference, the bottom of the partition plate 8 is connected with the shell 1 in a closed manner, and the top of the partition plate 8 forms a gap with the shell 1, so that the desulfurization slurry area and the absorption liquid regeneration area are only connected at the top.

[0036] In order to further realize the partition flashing of the desulfurization slurry and the absorption liquid without interference, the outer wall of the partition plate 8 is coated with a high polymer material.

[0037] The desulfurization slurry outflow pipe 4 is connected with a desulfurization tower, and the absorption liquid outflow pipe 9 is connected with a water heat recovery tower, so as to facilitate the recycling of the absorption liquid.

[0038] A working method of an absorption liquid regeneration device for flue gas waste heat recovery, based on the above-mentioned absorption liquid regeneration device for flue gas waste heat recovery, comprising:

[0039] The negative pressure device provides a negative pressure environment, the desulfurization slurry spraying device sprays the desulfurization slurry to the desulfurization slurry area, the absorption liquid spraying device sprays the dilute absorption liquid to the absorption liquid regeneration area, the low-temperature desulfurization slurry is discharged by the desulfurization slurry outlet pipe 4, the concentrated absorption liquid is discharged by the absorption liquid outlet pipe 9, and the flash steam is discharged by the steam outlet 5 after demisting.

[0040] To make the objects, technical solutions, and advantages of the embodiments of the present application clearer, the following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations.

[0041] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed application, but only represents selected embodiments of the application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative labor are within the scope of protection of the present application.

[0042] It should be noted that: similar reference numbers and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0043] In the description of the embodiments of the present application, it should be noted that if the terms "upper", "lower", "horizontal", "inner", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship when the product of the present application is used, only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, therefore, it cannot be understood as a limitation on the present application. In addition, the terms "first", "second", and the like are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0044] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly inclined. For example, "horizontal" only means that its direction is relatively more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0045] In the description of the embodiments of the present application, it also needs to be explained that, unless otherwise explicitly specified and limited, if the terms "arrange", "install", "connect", "connect" appear, they should be understood in a broad sense, for example, they can be fixedly connected, or can be detachably connected, or integrally connected; can be mechanically connected, or can be electrically connected; can be directly connected, or can be indirectly connected through an intermediate medium, or can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0046] The present application will be further described in detail below in conjunction with the accompanying drawings:

[0047] Embodiments

[0048] As shown in Figure 1 and Figure 2 The present embodiment provides an absorption liquid regeneration device for flue gas waste heat recovery, comprising: a shell 1, a first spray nozzle 2-1, a desulfurization slurry distribution pipe 3, an absorption liquid distribution pipe 7, a second spray nozzle 2-2, a demister 6, a partition plate 8, a desulfurization slurry outlet pipe 4 and an absorption liquid outlet pipe 9. The desulfurization slurry is the slurry produced after wet flue gas desulfurization in the desulfurization tower, flows into the device from the desulfurization slurry distribution pipe 3, is sprayed out through the first spray nozzle 2-1, and flashes in a negative pressure environment provided by a vacuum pump to produce flash steam and low-temperature desulfurization slurry. The low-temperature desulfurization slurry flows out from the desulfurization slurry outlet pipe 4 and is pumped back to the desulfurization tower by a low-temperature slurry pump for recycling.

[0049] The absorption liquid is dilute absorption liquid after low-temperature saturated wet flue gas water heat recovery by an absorption heat pump, enters the device from the absorption liquid distribution pipe 7, is sprayed out through the second spray nozzle 2-2, flashes and regenerates in a negative pressure environment to produce flash steam and concentrated absorption liquid, and the concentrated absorption liquid flows out from the absorption liquid outlet pipe 9 and returns to the absorption heat pump for recycling.

[0050] The partition plate 8 is a partition plate coated with a high molecular material and having a certain height, which is used to separate the absorption liquid and the desulfurization slurry to avoid their contact and mixing.

[0051] The upper part of the device is communicated, so that the whole device is maintained at the same negative pressure. The steam produced by flashing of the absorption liquid and the desulfurization slurry flows out from the steam outlet 5 and is sent to a condenser to recover water and heat therein. The vacuum of the device is maintained by a vacuum pump, and the air exhaust is also from the steam outlet 5. After the steam is condensed, the non-condensable gas is exhausted.

[0052] The specific implementation process is as follows: 2000m 3 / h of desulfurization slurry flows into the regeneration device from the desulfurization slurry distribution pipe 3 and is dispersed in the device in the form of droplets to flash, 1500m 3The absorption liquid from the absorption liquid distribution pipe 7 flows into the regeneration device and is dispersed in the form of droplets to occur flash evaporation, and the total volume of the regeneration device is 160 m 3 , and the two parts each account for half. The absolute pressure in the regeneration device is 20 kPa, and at this time, two vacuum pumps are required, with a gas extraction amount of 3700 m 3 / h and a single power of 140 kW.

[0053] In the dispersion arrangement scheme, to achieve the same desulfurization slurry and absorption liquid processing capacity and absolute pressure in the device, the following are required: (1) desulfurization slurry: the volume of the regeneration device is 120 m 3 , two vacuum pumps are required, with a gas extraction amount of 3000 m 3 / h and a single power of 110 kW; (2) absorption liquid: the volume of the regeneration device is 100 m 3 , two vacuum pumps are required, with a gas extraction amount of 2500 m 3 / h and a single power of 85 kW.

[0054] Therefore, the absorption liquid regeneration device for flue gas waste heat recovery provided in the embodiment can reduce the total volume of the regeneration system, reduce the equipment requirements of the vacuum pump, and reduce the power consumption of the vacuum pump.

[0055] The embodiment provides an absorption liquid regeneration device for flue gas waste heat recovery and a working method thereof. The device separates the inner cavity of the shell into a desulfurization slurry area and an absorption liquid regeneration area, and the two areas are only connected at the top. Such a layout can realize flash evaporation of the desulfurization slurry and the absorption liquid without interference, can ensure that flash evaporation of the desulfurization slurry and absorption liquid regeneration are simultaneously performed in the same negative pressure environment constructed by only one negative pressure device, and can reduce the number of negative pressure devices, that is, reduce investment and energy consumption. The device recovers water heat in two stages through desulfurization slurry flash evaporation and saturated wet flue gas solution absorption, effectively improves flue gas water heat recovery rate, improves the utilization efficiency of the vacuum pump by performing desulfurization slurry flash evaporation and dilute solution flash regeneration in the same flash evaporation device, and has the advantages of simple principle and structure, easy operation and maintenance, high cost performance, and good popularization and application value.

[0056] Compared with the prior art, the following advantages are obtained:

[0057] The device and method recover water heat in two stages through desulfurization slurry flash evaporation and saturated wet flue gas solution absorption, effectively improve flue gas water heat recovery rate, improve the utilization efficiency of the vacuum pump by performing desulfurization slurry flash evaporation and dilute solution flash regeneration in the same flash evaporation device, and reduce the number of required vacuum pumps, thereby reducing equipment cost and vacuum pump power consumption.

[0058] Therefore, the device and the method reduce the number of vacuum pumps, i.e. reduce investment and energy consumption of the vacuum pumps, by simultaneously performing flash evaporation of the desulfurization slurry and regeneration of the absorption liquid under the same negative pressure environment and sharing the vacuum pumps. In addition, the device and the method improve the layout of the absorption liquid regeneration device, increase a coated polymer material partition in the device, and realize partitioned flash evaporation and non-interference of the desulfurization slurry and the absorption liquid.

[0059] The above embodiment is only one of the implementation manners of the technical scheme of the present application, and the scope of the present application is not limited to the above embodiment, but also includes any changes, substitutions and other implementation manners that are easily thought of by those skilled in the art within the technical scope disclosed by the present application.

Claims

1. An absorption liquid regenerating device for flue gas heat recovery, characterized by, It comprises a shell (1), a negative pressure device for keeping the inner cavity of the shell (1) in vacuum condition; The inner cavity of the shell (1) is divided into a desulfurization slurry area and an absorption liquid regeneration area, and the two areas are only connected at the top; The desulfurization slurry area is provided with a desulfurization slurry spraying device for spraying desulfurization slurry, and the bottom of the desulfurization slurry area is provided with a desulfurization slurry outflow pipe (4) for discharging low-temperature desulfurization slurry; The absorption liquid regeneration area is provided with an absorption liquid spraying device for spraying dilute absorption liquid, and the bottom of the absorption liquid regeneration area is provided with an absorption liquid outflow pipe (9) for discharging concentrated absorption liquid; The top of the shell (1) is provided with a steam outlet (5).

2. The absorption liquid regenerator for flue gas waste heat recovery according to claim 1, characterized in that, The desulfurization slurry area and the absorption liquid regeneration area are provided with a demister (6) above for preventing the mixing of desulfurization slurry and absorption liquid.

3. The absorption liquid regenerator for flue gas waste heat recovery according to claim 1, characterized in that, The desulfurization slurry spraying device comprises a desulfurization slurry distribution pipe (3) inserted into the desulfurization slurry area, and the desulfurization slurry distribution pipe (3) is connected with a first spraying nozzle (2-1) with downward spray port.

4. The absorption liquid regenerator for flue gas waste heat recovery according to claim 1, characterized in that, The absorption liquid spraying device comprises an absorption liquid distribution pipe (7) inserted into the absorption liquid regeneration area, and the absorption liquid distribution pipe (7) is connected with a second spraying nozzle (2-2) with downward spray port.

5. The absorption liquid regenerator for flue gas waste heat recovery according to claim 1, characterized in that, The negative pressure device comprises a vacuum pump, which is connected with the desulfurization slurry area or the absorption liquid regeneration area.

6. The absorption liquid regenerator for flue gas waste heat recovery according to claim 1, characterized in that, The inner cavity of the shell (1) is divided into a desulfurization slurry area and an absorption liquid regeneration area by a partition plate (8), the bottom of the partition plate (8) is connected with the shell (1), and the top of the partition plate (8) forms a gap with the shell (1).

7. An absorption liquid regenerating device for flue gas waste heat recovery according to claim 6, characterized in that, The outer wall of the partition plate (8) is coated with a high polymer material.

8. The absorption liquid regenerator for flue gas waste heat recovery according to claim 1, characterized in that, The desulfurization slurry outflow pipe (4) is connected with a desulfurization tower.

9. The absorption liquid regenerator for flue gas waste heat recovery according to claim 1, characterized in that, The absorption liquid outflow pipe (9) is connected with a hydrothermal recovery tower.

10. A method of operation of an absorption liquid regenerator for flue gas heat recovery, according to any one of claims 1-9, characterized in that, It comprises: The negative pressure device provides a negative pressure environment, the desulfurization slurry spraying device sprays desulfurization slurry into the desulfurization slurry area, the absorption liquid spraying device sprays dilute absorption liquid into the absorption liquid regeneration area, low-temperature desulfurization slurry is discharged through the desulfurization slurry outflow pipe (4), concentrated absorption liquid is discharged through the absorption liquid outflow pipe (9), and flash steam is discharged through the steam outlet (5).

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