JP2003027959A - Device for collecting water from exhaust gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for collecting water from exhaust gas capable of restricting a drift of exhaust gas, and improving heat recovering efficiency. SOLUTION: This device is provided with a collecting chamber to which exhaust gas discharged from a heat source flows in, plural sprinkling parts to sprinkle water respectively for plural layers parted in the collecting chamber, and plural collecting parts to collect sprinkled water and condensed water corresponding to the sprinkling parts. The sprinkling part in each layer is disposed in such a way that sprinkled water directly exchange heat with exhaust gas flow. A flow passage is formed in such a way that a part or all of water collected from the collecting parts returns to a part or all of the sprinkling parts as sprinkled water. A flow passage is also formed to take water collected from the collecting part positioned on the inflow side of exhaust gas to the external of the device.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a water recovery device for recovering water from combustion exhaust gas.

[0002]

2. Description of the Related Art Regarding the method of recovering water from exhaust gas containing a large amount of water, technology in the field of HAT (Humid Air Turbine) cycle such as water recovery from exhaust gas of a gas turbine,
For example, in Japanese Unexamined Patent Publication No. 56-12006, exhaust gas is supplied to a cooling tower and is brought into alternating current contact with atomized cooling water to condense and separate water vapor contained in the exhaust gas, and then exhausted to the atmosphere as exhaust gas with reduced humidity. Japanese Patent Application Laid-Open No. 11-1
No. 17764 gazette discloses that when water is recovered from exhaust gas, it is divided into a plurality of water recovery parts, and a part of the liquid recovery part recovery water on the outlet side where the temperature of the combustion exhaust gas is low is partially separated on the inlet side where the temperature of the combustion exhaust gas is high. There is a description that the cooling water is supplied to the cooling water spraying part, and the recovered water obtained in that region is further supplied to the cooling water spraying part located on the inlet side where the temperature of the combustion exhaust gas is high.

[0003]

Exhaust gas containing a large amount of moisture can collect water by condensing water vapor when the temperature is lowered below the dew point. In the conventional water recovery device, the exhaust gas generally causes a nonuniform flow, which may increase the heat exchange loss. In addition, due to lack of a heat exchange area, there is a case where sufficient heat exchange is not performed and the thermal energy of the exhaust gas is not sufficiently recovered and is released to the atmosphere.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a water recovery apparatus that suppresses uneven flow of exhaust gas and improves heat recovery efficiency.

[0005]

In order to achieve the above object of the present invention, a recovery chamber into which exhaust gas discharged from a heat source flows and a recovery chamber are divided into a plurality of layers, and water is supplied to each of the divided layers. Equipped with a plurality of spraying parts for spraying and a plurality of collecting parts for collecting sprayed water and condensed water corresponding to the spraying parts, and the spraying parts of each layer are arranged so that the sprayed water and the exhaust gas flow directly exchange heat. To do. A part or all of the water recovered from this recovery part forms a flow path as sprayed water that returns to part or all of the spray part, and the water recovered from the recovery part located on the exhaust gas inflow side is This can be achieved by forming a flow path that is taken out to the outside. In the present invention, the collection chamber includes a case where the collection chamber is divided into a plurality of collection chambers and a case where the collection chambers are assembled as one unit.

[0006]

1 is a schematic diagram of a water recovery system 7 and a gas turbine plant according to an embodiment of the present invention. The air sucked through the air suction pipe 21 and compressed by the air compressor 2 is sent to the combustor 4 through the air discharge pipe 22. The air introduced to the combustor 4 is supplied with fuel by the fuel pipe 20 and the steam generator 5 supplied by the steam supply pipe 25.
It burns with the steam generated in. The high temperature combustion gas generated in the combustor 4 is sent to the gas turbine 1 via the exhaust pipe 23 and drives the generator 3 connected to the gas turbine 1 via a shaft. The exhaust gas that has driven the gas turbine 1 is guided by the high temperature exhaust pipe 24, and after the heat is recovered by the steam generator 5, the exhaust gas of the present embodiment is passed through the exhaust gas inflow pipe 27, the heat exchanger 6, and the exhaust gas inflow pipe 28. To the water recovery device 7. Exhaust gas after combustion, which contains a large amount of water vapor,
After being cooled by the heat exchanger 6, it flows into the water recovery device 7 via the exhaust gas inflow pipe 28 and the branch passages 51, 52, 53, where it comes into direct contact with the cooling water and is cooled to become wet steam.
A part is condensed and collected. The remaining exhaust gas is heated by the heat exchanger 6 through the mist removing device 11 and the gas outflow pipe 29, and is then discharged to the atmosphere by a chimney (not shown) via the exhaust pipe 30.

The water recovery device 7 divides the recovery chamber 13 into a plurality of parts, and in the present embodiment, is constituted as recovery chambers 31, 32 and 33, for example. In the recovery chamber 31, the cooling water pipe 41
The cooling water that has passed through is sprayed as sprayed water from the spraying section 71a so as to intersect (for example, orthogonally) the flow of the exhaust gas, and the sprayed water and the condensed water are recovered by the water recovery section 71b. Similarly, collection room 3
The cooling water that has passed through the cooling water pipe 41 in 2 and 33 is also sprayed as sprayed water in the recovery chambers 32 and 33 from the corresponding spraying portions 71a so as to intersect the flow of the exhaust gas, and the sprayed water and the condensed water correspond to each other. The water is recovered by the water recovery unit 71b. Here, the respective water recovery parts 71b in the recovery chambers 31, 32, 33
The two are connected to the recovered water pipe 42 via a flow path, and the recovered water is guided to the return water pipe 43 via the recovered water pipe 42, the switching valve 80a and the flow rate control device 9 and cooled by the cooling water cooler 8. Then, it is circulated as cooling water through the cooling water pipe 41 and reused.

Here, a part or all of the recovered water recovered by the water recovery section 71b is sent again to the upstream cooling water spraying section 72a via the cooling water pipe 41 to serve as sprayed water for the cooling water spraying section 72a. used. In addition, the recovery chamber 31, 32, 33
Of the water collecting units 71b, 72b, 73b are connected between the layers, and the collected water is collected by the collected water pipes 42, 44, 46, respectively.
Flows to. The collected water that has passed through the collected water pipes 42, 44 and 46 does not mix when the switching valves 80b and 80c are closed.

The sprayed water sent to the cooling water sprayer 73a on the most upstream side absorbs the latent heat of condensation of the exhaust gas through the water recovery parts 71b and 72b, and therefore has a higher temperature than the sprayed water of 71a. . This high-temperature recovered water is supplied to the switching valve 80c.
Closed and the switching valve 80d opened, the recovery water pipe 46
Water treatment device 1 without being mixed with low temperature recovered water
0, the recovered water tank 12, the makeup water supply pipe 26,
It is supplied to the steam generator 5, is used as make-up water, and is mixed in the discharge air of the compressor 2 as steam. The heat exchanger 6 is an example for heating the exhaust gas after water recovery, and if a separate heat source is available, this may be used.

Next, the behavior of the sprayed droplets is shown in FIGS. 2 and 3.
Shown in. FIG. 2 is an example of a trial calculation of the terminal velocity when the droplet is allowed to naturally drop in the air. The terminal velocity is determined by the balance between the gravity acting on the droplet and the air resistance. For example, the terminal velocity of a droplet having a diameter of 3 mm is 2.5 m / s. This means that droplets with a diameter of 0.3 mm may not fall under the condition that there is an air flow with a blowing velocity of more than 2.5 m / s, and may be entrained in the air stream and scattered. ing.

The droplets discharged from the cooling water sprinkling portion 72a have a droplet diameter and an initial velocity according to the type of nozzle (not shown) and the discharge pressure, and the discharge pressure (pressure difference) of the nozzle. Is 0.1 to 0.3 MPa, for example, there may be a combination of a sprayed droplet diameter of 0.3 mm and an initial velocity of 15 to 25 m / s.

FIG. 3 is a trial calculation of the position below the nozzle where the droplet ejected from the nozzle can reach when the air has a blowing velocity of 2 m / s.
As apparent from FIG. 2, since the terminal velocity of the droplets of 0.2 mm or less is smaller than 2 m / s, all the droplets in the range shown in the graph of FIG. Due to its speed, it can proceed downwards until it has exhausted its kinetic energy against air resistance. Therefore, if these minute droplets are captured within the range shown in FIG. 3, they can be collected before the droplets are scattered. The diameter is 0.
If a distance of 1.0 m is taken for a droplet of 3 mm, it becomes possible to recover when the discharge pressure (pressure difference) of the nozzle is 0.1 MPa. In addition, since the high-speed jet flow ejected from the cooling water sprinkling portion 72a is atomized by the shearing force with the air, it is considered that the distance is 0.2 m as a sufficient distance for forming the cooling water sprinkling portion 72a droplets. Therefore, it is expected that more droplets can be collected by providing the droplet collecting unit in the range of 0.2 m to 1.0 m from the cooling water spraying unit 72a.

10 and 11 are conceptual diagrams showing the function of the rectifying action.

FIG. 10 (a) is a conceptual perspective view of a conventional water recovery device 7, and FIG. 10 (b) is a view showing a drift condition in FIG. 10 (a). FIG. 11A is a conceptual perspective view of the water recovery device 7 of this embodiment, and FIG. 11B is a diagram showing the flow of exhaust gas in FIG. 11A.

The inlet portion of the conventional water recovery device 7 shown in FIGS. 10 (a) and 10 (b) generally has a structure in which the exhaust gas is taken in by expanding or bending the exhaust gas inflow pipe 28 due to the limitation of the installation space. A separation region 28c was generated inside the flow, and a nonuniform flow 28b was formed in the recovery chamber 13, hindering heat exchange. However, with the multi-layer structure of this embodiment shown in FIGS. 11A and 11B, the flow passage area per layer is reduced,
The flow rectifying action is promoted, and even if the uneven flow 28b is generated, the area thereof is smaller than that of the conventional structure, and the heat exchange loss can be suppressed.

According to this embodiment shown in FIGS. 11 (a) and 11 (b), the recovery chamber 13 is divided into a plurality of layers and arranged three-dimensionally so that the cross-sectional area of the recovery chamber 13 in the exhaust gas flow direction can be reduced. When the total sum is the same, the flow passage cross-sectional area per one layer becomes smaller due to the multilayer structure, while the heat transfer region per unit flow passage cross-section increases and the flow rectifying action is promoted, and the separation region 28c decreases. The heat exchange can be made more uniform over each recovery chamber cross section, and the heat exchange loss can be suppressed. Further, since the distance over which the sprayed water scatters is also shortened, the sprayed water reaches the water recovery part 71b before being entrained by the exhaust gas, the sprayed water discharged at the same time as the exhaust gas is reduced, and the water recovery amount is increased. . Therefore, the water recovery capacity is increased, highly efficient water recovery can be performed, the size can be reduced, the installation space can be reduced, and the manufacturing cost can be reduced. Further, since water of different temperature levels can be recovered from the exhaust gas, it is possible to utilize energy by using hot water as external work.

FIG. 4 shows a water recovery device 7 and a gas turbine plant according to another embodiment. In the configuration of FIG. 1, the exhaust gas flow is directed from the bottom to the top so that the direction of the exhaust gas flow is opposite to the spray direction of the spray water. The distance between the cooling water sprinkling portion 71a and the water collecting portion 71b is set in the range of 0.2 to 1 m. The function of each device is the same as in FIG.

FIG. 5 shows a water recovery device 7 and a gas turbine plant of another embodiment. In the configuration of FIG. 1, the direction of the exhaust gas flow is the direction of the sprayed water, and the cooling water sprayer 71a is used. The distance to the water recovery part 71b is 0.2 to 1
The range is m 2. The function of each device is the same as in FIG.

FIG. 6 shows a water recovery device 7 and a gas turbine plant of another embodiment, which is based on FIG. 4, but an embodiment in which the recovered water on the high temperature side and the recovered water on the low temperature side are mixed and recovered. Is.

FIG. 7 shows another embodiment of the water recovery device 7 of FIG. 1, in which the direction of the exhaust gas flow is upward (opposite to the direction of gravity) and the sprayed water is crossed (eg orthogonal) thereto. And the distance between the cooling water sprinkling portion 71a and the water collecting portion 71b is set in the range of 0.2 to 1 m 2. The function of each device is the same as in FIG.

FIG. 8 shows a water recovery device 7 of another embodiment, which is based on FIG. 7, but the arrangement of the cooling water sprinkling parts and the collecting part of the sprinkling parts of each layer are alternately arranged. The spraying directions of the adjacent spraying parts are opposite. For example, the cooling water sprinkling unit 7
1a and 73a are sprayed in the same direction, and the cooling water sprayer 7
The spray water of 2a is directed in the opposite direction, and the water recovery unit 71
The positions of b, 72b, 73b are set to the cooling water sprinkling portions 71a, 72.
It is installed opposite to a and 73a. The exhaust gas is caused to flow so as to intersect (for example, at right angles) with each spray water, and the distance between the cooling water spray section 71a and the water recovery section 71b is set to 0.2-1 m.
It is an example of the range.

FIG. 9 shows another embodiment of the water recovery device 7. In the configuration of FIG. 4, the exhaust gas is directed upwards (opposite the direction of gravity) to the sprayed water, and is adjacent to the sprayed water. Due to the configuration in which an opening is formed between the water collecting parts 71b that discharges the exhaust gas having a local blowing velocity of 4 to 6 m / s, the sprayed water receives the pressure of the exhaust gas and the opening of the water collecting part 71b. By avoiding this, the recovered water is efficiently recovered by the water recovery unit 71b. Cooling water spraying unit 71a and water recovery unit 71b
This is an example in which the distance between and is within the range of 0.2 to 1 m.

FIG. 12 shows a water recovery system 7 and a gas turbine plant according to another embodiment. In the configuration of FIG. 1, the exhaust gas flow is directed laterally so as to oppose the spray water spray direction. The distance between the cooling water sprinkling portion 71a and the water collecting portion 71b is in the range of 0.2 to 1 m.

[0024]

According to the present invention, there is an effect that it is possible to provide a water recovery apparatus that suppresses uneven flow of exhaust gas and rectifies it to improve heat exchange efficiency of exhaust gas.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an embodiment of the present invention.

FIG. 2 is an example of trial calculation of a terminal velocity when a droplet naturally drops in air.

FIG. 3 is an example of trial calculation of a droplet reaching distance at a blowing velocity of 2 m / s.

FIG. 4 is a schematic diagram showing another embodiment of the present invention.

FIG. 5 is a schematic diagram showing another embodiment of the present invention.

FIG. 6 is a schematic diagram showing another embodiment of the present invention.

FIG. 7 is a schematic diagram showing another embodiment of the present invention.

FIG. 8 is a schematic diagram showing another embodiment of the present invention.

FIG. 9 is a schematic diagram showing another embodiment of the present invention.

FIG. 10 is a schematic perspective view of a conventional water recovery device from exhaust gas.

FIG. 11 is a schematic perspective view of an apparatus for recovering water from exhaust gas according to the present invention.

FIG. 12 is a schematic diagram showing another embodiment of the present invention.

[Explanation of Codes] 1 ... Gas turbine, 2 ... Air compressor, 3 ... Generator, 4 ...
Combustor, 5 ... Steam generator, 6 ... Heat exchanger, 7 ... Water recovery device, 8 ... Cooling water cooler, 9 ... Flow control device, 10 ... Water treatment device, 11 ... Mist removal device, 12 ... Recovered water tank,
13, 31, 32, 33 ... Recovery chamber, 20 ... Fuel pipe, 21
... air intake pipe, 22 ... air discharge pipe, 23,30 ... exhaust pipe, 24 ... high temperature exhaust pipe, 25 ... steam supply pipe, 26 ... makeup water supply pipe, 27,28 ... exhaust gas inflow pipe, 28b ... unbalanced flow,
28c ... Separation area, 29 ... Exhaust gas outflow pipe, 41 ... Cooling water pipe, 42, 44, 46 ... Recovery water pipe, 43 ... Return water pipe, 5
1, 52, 53 ... Branch path, 71a, 72a, 73a ... Cooling water sprinkling section, 71b, 72b, 73b ... Water collecting section, 80
a, 80b, 80c, 80d ... Switching valve.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shohei Numata             2-12-1 Omika-cho, Hitachi-shi, Ibaraki Prefecture             Ceremony Company Hitachi, Ltd.

Claims (11)

[Claims] 1. A recovery chamber into which exhaust gas emitted from a heat source flows, a plurality of spraying units that divide the recovery chamber into a plurality of layers and spray water in each layer, and spray water corresponding to the spraying units. And a plurality of recovery parts for recovering condensed water, and the spraying part of each layer is arranged so that the sprayed water and the exhaust gas flow of each layer directly exchange heat, and one of the water recovered from the recovery part is disposed. A part or all of the sprayed water forms a flow path that returns to a part or all of the sprayed part, and also a flow path through which water recovered from the recovery part located on the exhaust gas inflow side is taken out of the device. A device for recovering water from exhaust gas, which is characterized in that 2. A recovery chamber into which exhaust gas discharged from a heat source flows, and the recovery chamber is divided into a plurality of stages in the exhaust gas flow direction, and a plurality of spraying sections and a plurality of recovery sections are opposed to each other. The spraying section is provided so that the exhaust gas flow and the sprayed water directly exchange heat with each other, and the collecting section is arranged at a position where the sprayed water and the condensed water are collected respectively. A part or all of the collected water should be diverted to the sprayed water in the previous stage, and a flow path through which the water collected from the collecting part located on the exhaust gas inflow side is taken out of the device should be formed. Characteristic water recovery device from exhaust gas. 3. A plurality of recovery chambers into which exhaust gas discharged from a heat source flows, a plurality of spraying units and a plurality of recovery units for each recovery chamber, and the spraying units respectively provide an exhaust gas flow and spray water. Are arranged so as to directly exchange heat with each other, and the collecting section is arranged at a position where sprayed water and condensed water are respectively collected, and a part or all of the water collected from the rear side of each collecting chamber The water recovery device from exhaust gas, wherein the water recovery device from the exhaust gas also forms a flow path through which water recovered from the recovery part on the exhaust gas inflow side is extracted to the outside of the device. 4. A collection chamber into which exhaust gas emitted from a heat source flows, a plurality of collection chambers in which the collection chambers are stacked, and a plurality of spraying units for spraying water in each recovery chamber, and correspondingly sprayed water and condensed water. And a plurality of recovery parts for recovering, the spraying part of each layer is arranged so that the sprayed water and the exhaust gas directly exchange heat,
Each of the collecting sections forms a flow path in which the same row positions of adjacent layers communicate with each other, and water collected from the collecting section returns to the spraying section as sprayed water, and is located on the most upstream side of each layer. An apparatus for recovering water from exhaust gas, characterized in that it also forms a flow path through which water recovered from the recovery section is taken out of the apparatus. 5. The apparatus for recovering water from exhaust gas according to claim 4, wherein the flow of the exhaust gas is in a direction opposite to the spraying direction of each spraying section of the cooling water. 6. The apparatus for recovering water from exhaust gas according to claim 4, wherein the flow direction of the exhaust gas is the spray direction of each spray section of the cooling water. 7. The apparatus for recovering water from exhaust gas according to claim 1, wherein the distance between the cooling water spraying section and the water collecting section is 0.2 to 1 m. 8. A water recovery system from exhaust gas according to claim 1, wherein the flow direction of the exhaust gas is opposite to the gravity direction and the spraying direction of the cooling water spraying portion is a direction intersecting with the flow of the exhaust gas. . 9. The exhaust gas from the exhaust gas according to claim 8, wherein cooling water sprinkling parts and collecting parts of the sprinkling parts are alternately arranged in each layer, and the sprinkling directions of the adjacent spraying parts are opposite to each other. Water recovery device. 10. The exhaust gas according to claim 5, wherein the exhaust gas is caused to flow at a flow velocity of 4 to 6 m / sec from an opening of an adjoining recovery part, facing the spraying direction of each spraying part. Water recovery device. 11. An air compressor, a combustor for combusting compressed air of the air compressor together with fuel and steam, a gas turbine driven by combustion gas of the combustor, and exhaust gas discharged from the gas turbine. An inflowing recovery chamber, and a plurality of spraying sections that divide the recovery chamber into a plurality of layers and spray water in each layer,
A plurality of collecting units for collecting sprayed water and condensed water corresponding to the spraying unit, and the spraying unit of each layer is arranged so that the sprayed water and the exhaust gas flow of each layer directly exchange heat; A part or all of the water recovered from the recovery part forms a flow path that returns to part or all of the spray part as sprayed water, and the water recovered from the recovery part located on the exhaust gas inflow side is A gas turbine plant having a water recovery device from exhaust gas, characterized in that it also forms a flow path taken out to the outside.