JP7596320B2 - Direct Contact Condenser - Google Patents

Description

An embodiment of the present invention relates to a direct contact condenser.

In geothermal power plants, a condenser is a device that condenses the steam contained in the turbine exhaust by heat exchange between the high-temperature turbine exhaust and low-temperature cooling water, and maintains the turbine exhaust pressure at negative pressure. Since geothermal power plants do not need to reuse the condensate from the condensed steam, direct contact condensers are often used, as they are simple in structure and have advantages in heat exchange. Direct contact condensers are mainly classified into tray (perforated plate) type and droplet spray type (spray type). The tray type uses the dynamic pressure of steam to atomize the cooling water that falls from the tray, while the spray type uses a spray nozzle to atomize the cooling water and spray it into the turbine exhaust. Spray type condensers include downward exhaust type (upward inflow type) and horizontal exhaust type (horizontal inflow type).

The steam supplied from geothermal production wells generally contains non-condensable gases such as carbon dioxide. Since non-condensable gases impede heat transfer, it is important for the condenser that condenses the steam to cool and discharge the non-condensable gases without allowing them to accumulate, in order to maintain a negative exhaust pressure for the turbine.

Japanese Patent Application Publication No. 11-63857 JP 2010-270925 A JP 2020-26932 A JP 2018-35999 A

When the turbine exhaust gas comes into contact with the cooling water in a direct contact condenser, the water vapor contained in the turbine exhaust gas is cooled and condensed, gradually decreasing the flow rate of the turbine exhaust gas. As a result, the flow rate of the turbine exhaust gas on the downstream side in the flow direction is slower than that on the upstream side, making it more likely for the flow to stagnate. Non-condensable gases collect in the area where the flow stagnates, which reduces the heat transfer efficiency between the turbine exhaust gas and the cooling water and can cause the vacuum in the condenser to deteriorate. A deterioration in the vacuum in the condenser reduces the power generation efficiency of the geothermal power plant.

The problem that this invention aims to solve is to provide a direct contact condenser that can maintain the degree of vacuum inside the condenser by suppressing flow stagnation inside the downward exhaust type direct contact condenser.

In order to solve the above problems, the direct contact condenser of one embodiment is a downward exhaust type condenser in which a cooling water supply pipe is provided inside a steam condensation section into which turbine exhaust gas flows, and the direct contact condenser is provided with a plurality of spray nozzles arranged in the flow direction of the turbine exhaust gas, and of the plurality of spray nozzles, the spray nozzle arranged most downstream with respect to the flow direction of the turbine exhaust gas sprays cooling water in an oblique upstream direction or perpendicular to the flow direction of the turbine exhaust gas.

Schematic diagram of a geothermal power plant according to the first embodiment 1 is a schematic diagram of a vertical cross section of a direct contact condenser according to a first embodiment; FIG. 1 is an enlarged view of a portion A of a direct contact condenser according to a first embodiment; FIG. 1 is an enlarged view of a portion A of a direct contact condenser according to a modified example of the first embodiment. FIG. 1 is an enlarged view of a portion A of a direct contact condenser according to a modified example of the first embodiment. Enlarged view of a direct contact condenser according to a second embodiment. FIG. 13 is an enlarged view of a direct contact condenser according to a modified example of the second embodiment. FIG. 13 is an enlarged view of a direct contact condenser according to a modified example of the second embodiment. Enlarged view of a direct contact condenser according to a third embodiment. FIG. 13 is an enlarged view of a direct contact condenser according to a modified example of the third embodiment. FIG. 13 is an enlarged view of a direct contact condenser according to a modified example of the third embodiment.

The following describes the form for implementing the invention.

First Embodiment
A first embodiment will be described with reference to the drawings. Fig. 1 is a schematic diagram of a geothermal power plant according to the first embodiment. As shown in Fig. 1, a geothermal power plant 30 includes a gas-liquid separator 31, a dehumidifier 32, a steam turbine 33, a generator 34, and a condenser 1. Arrows in Fig. 1 indicate the flow of water vapor or water.

The gas-liquid separator 31 separates the geothermal fluid from the production well into main steam and hot water. The separated main steam has further water droplets removed by the dehumidifier 32, then passes through a steam control valve (not shown) installed between the dehumidifier 32 and the steam turbine 33 and flows into the steam turbine 33.

The steam turbine 33 performs expansion work from the main steam, and rotates and drives the generator 34 connected via a turbine rotor (not shown). The generator 34 converts the rotational energy from the steam turbine 33 into electrical energy to generate electricity. After performing expansion work in the steam turbine 33, the main steam flows into the condenser 1 as turbine exhaust.

The condenser 1 condenses the water vapor contained in the turbine exhaust by cooling it. The condensed water condensed in the condenser 1 is combined with the hot water separated in the gas-liquid separator 31 and the water droplets removed in the dehumidifier 32, and is sent to the reinjection well.

Next, the configuration of the condenser 1 will be described in more detail. Figure 2 is a schematic diagram of a vertical cross section of a direct contact condenser according to the first embodiment. Figure 3 is an enlarged view of part A in Figure 2. Figures 4 and 5 are enlarged views of part A according to a modified example of the first embodiment.

As shown in FIG. 2, the condenser 1 is a downward exhaust type direct contact condenser having a turbine duct 10 into which the turbine exhaust gas discharged from the steam turbine 33 flows, a steam condenser section 11 connected to the turbine exhaust duct 10 and into which the turbine exhaust gas from the turbine exhaust duct 10 flows, a cooling water supply pipe 12 that supplies cooling water to the inside of the steam condenser section 11, and a gas cooling section 14 that is connected to the opposite side of the steam condenser section 11 from the turbine exhaust duct 10.

The turbine exhaust duct 10 is connected above the steam condensation section 11 and extends to allow the turbine exhaust to flow downward. The steam condensation section 11 is configured to allow the turbine exhaust from the turbine exhaust duct 10 to flow in and to condense the water vapor contained in the turbine exhaust by directly contacting the turbine exhaust with the cooling water supplied from the cooling water supply pipe 12.

The cooling water supply pipe 12 is provided inside the steam condensation section 11 in the y-axis direction. A plurality of spray nozzles 13a to 13c are provided at a predetermined distance from each other in the longitudinal direction (y-axis direction) of the cooling water supply pipe 12. Here, the spray nozzle provided in the cooling water supply pipe 12 on the most upstream side in the flow direction is referred to as spray nozzle 13a, the spray nozzle provided in the cooling water supply pipe 12 on the most downstream side in the flow direction is referred to as spray nozzle 13c, and the remaining spray nozzles are referred to as spray nozzle 13b. In this embodiment, such cooling water supply pipes 12 are arranged in three rows in the flow direction of the turbine exhaust gas inside the steam condensation section 11 (in the following description, these rows are referred to as tube rows), and two rows are provided in parallel in a direction perpendicular to the flow direction of the turbine exhaust gas, for a total of three rows and two rows of tube rows.

As shown in FIG. 3, the cooling water supply pipe 12 forms flow paths 21a to 21c inside the steam condensation section 11. The rows of cooling water supply pipes 12 are arranged at equal intervals so that the widths of the flow paths 21a to 21c (widths in the x-axis direction in FIG. 3) are uniform. In addition, spray nozzle 13a sprays cooling water on the wall side of the steam condensation section 11 close to spray nozzle 13a in an oblique upstream direction and an oblique downstream direction at an angle of 45 degrees to the flow direction. Spray nozzles 13b and 13c spray cooling water in an oblique downstream direction at an angle of 45 degrees to the flow direction.

Here, the oblique upstream direction means the upstream side from the direction perpendicular to the flow direction, and the oblique downstream direction means the downstream side from the direction perpendicular to the flow direction. In this embodiment, the oblique upstream direction is the direction inclined from the x-axis toward the positive z-axis direction, and the oblique downstream direction is the direction inclined from the x-axis toward the negative z-axis direction. Note that, although this embodiment illustrates an example in which the direction in which the spray nozzle sprays cooling water is at an angle of 45 degrees to the flow direction, this angle does not necessarily have to be 45 degrees.

The gas cooling section 14 is a cooling means for cooling the turbine exhaust gas that has not been condensed inside the steam condensation section 11, and in this embodiment, is a rectangular parallelepiped. The gas cooling section 14 is connected to the steam condensation section 11, and extends in the z-axis direction so that the turbine exhaust gas flowing in from below flows upward. The cooled turbine exhaust gas is discharged from the gas exhaust port 15.

Inside the gas cooling section 14, a cooling water supply pipe (not shown) and filler 16 are provided. The filler 16 is provided upstream of the flow path in the gas cooling section 14, has a surface for increasing the contact area with the turbine exhaust passing through the flow path, and is a contact medium with an increased surface area per volume, for example, protrusions and grooves formed on the surface. The cooling water supply pipe inside the gas cooling section 14 is provided above the filler 16 and downstream of the gas cooling section 14, sprays cooling water onto the filler 16, and sprinkles the cooling water on the surface of the filler 16. The gas cooling section 14 cools the turbine exhaust by contact between the cooling water flowing over the surface of the filler 16 and the turbine exhaust as the turbine exhaust passes through the filler 16.

A hot well 17 is provided below the steam condensation section 11 and the gas cooling section 14 in the z-axis direction. The hot well 17 stores the condensed water obtained by condensing the turbine exhaust gas by the steam condensation section 11, the cooling water sprayed from the cooling water supply pipe 12 in the steam condensation section 11, the cooling water sprayed from the cooling water supply pipe 12 in the gas cooling section 14, and the cooling water sprayed and flowing down from the surface of the filler 16.

Next, the operation of the direct contact condenser according to this embodiment will be described. In the condenser 1, the turbine exhaust, which is the main steam after performing expansion work in the steam turbine 33, flows from the turbine exhaust duct 10 into the steam condensation section 11. The turbine exhaust that flows into the steam condensation section 11 comes into direct contact with the cooling water sprayed from the spray nozzles 13a to 13c of the cooling water supply pipe 12, and the water vapor in the turbine exhaust condenses into condensed water. This condensed water is stored in the hot well 17 together with the cooling water sprayed from the cooling water supply pipe 12, the cooling water sprayed from the cooling water supply pipe 12 in the gas cooling section 14, and the cooling water that flows down from the surface of the filler 16, and is then sent to the reinjection well.

Here, if the turbine exhaust contains non-condensable gases such as water vapor and carbon dioxide, the uncondensed turbine exhaust, which contains water vapor that does not condense in the steam condenser section 11 and non-condensable gases, flows from the steam condenser section 11 into the gas cooling section 14, where it is further cooled and discharged to the outside from the gas exhaust port 15.

In the first embodiment described above, the rows of cooling water supply pipes 12 are arranged in two rows and three stages so that the widths of the flow paths 21a to 21c formed by the cooling water supply pipes 12 inside the steam condensation section 11 are uniform. The spray nozzle 13a sprays cooling water in the upstream and downstream directions at an angle of 45 degrees to the flow direction, and toward the wall side of the steam condensation section 11 close to the spray nozzle 13a, and the spray nozzles 13b and 13c spray cooling water in the downstream direction at an angle of 45 degrees to the flow direction.

By providing the configuration of the first embodiment, not only is the flow rate of the turbine exhaust gas uniform in the flow paths 21a to 21c formed between the cooling water supply pipes 12, but the amount of cooling water sprayed into the flow paths 21a to 21c is more uniform than in the past, so that the balance between the amount of cooling water and the amount of turbine exhaust gas can be maintained. Therefore, the turbine exhaust gas is uniformly cooled regardless of which flow path it passes through, and flow stagnation caused by the cooling condition of the turbine exhaust gas or the concentration gradient of non-condensable gas inside the steam condenser 11 can be prevented. As a result, the degree of vacuum inside the condenser 1 can be maintained, so that a decrease in the power generation efficiency of the power plant can be prevented.

As a modified example of the first embodiment, for example, as shown in FIG. 4, spray nozzle 13a may spray cooling water in an oblique upstream direction and an oblique downstream direction at an angle of 45 degrees to the flow direction and on the wall side of steam condensation section 11 close to spray nozzle 13a, spray nozzle 13c may spray cooling water in an oblique upstream direction at an angle of 45 degrees to the flow direction, and spray nozzle 13b may spray cooling water in an oblique downstream direction at an angle of 45 degrees to the flow direction.

As another variation of the first embodiment, for example, as shown in FIG. 5, spray nozzle 13a may spray cooling water in an oblique upstream direction and an oblique downstream direction at an angle of 45 degrees to the flow direction and on the wall side of steam condensation section 11 close to spray nozzle 13a, and spray nozzles 13b and 13c may spray cooling water in an oblique upstream direction at an angle of 45 degrees to the flow direction.

According to each of the modified examples of the first embodiment shown in FIG. 4 or FIG. 5, in addition to the same effects as the first embodiment, the spray nozzle 13b or 13c sprays the cooling water diagonally upstream with respect to the flow direction of the cooling water, thereby lengthening the heat exchange time between the turbine exhaust gas and the cooling water, and improving the cooling performance of the steam condenser 11. Therefore, the degree of vacuum inside the condenser 1 can be maintained, and the space in the height direction of the condenser 1 can be reduced.

In the first embodiment or its modified examples, the spray nozzles 13a to 13c need only spray the cooling water diagonally upstream or downstream with respect to the flow direction, and do not have to spray the cooling water diagonally upstream or downstream at an angle of 45 degrees with respect to the flow direction.

Second Embodiment
Next, a direct contact condenser according to a second embodiment will be described with reference to the drawings. In the following description, only the differences from the first embodiment will be described, and the same reference numerals will be used to designate the same parts as those in the first embodiment or the modified examples thereof, and detailed description thereof will be omitted.

The main difference between this embodiment and the first embodiment is the arrangement of the cooling water supply pipe 12 and the direction in which the spray nozzles 13a to 13c spray the cooling water.

As shown in FIG. 6, the cooling water supply pipe 12 according to this embodiment forms flow paths 22a and 22b inside the steam condensation section 11. The tube rows of the cooling water supply pipe 12 are arranged in two rows and three stages so that the flow paths 22a and 22b are of equal size, with one row (the tube row of the cooling water supply pipe 12 on the left side in FIG. 6) being arranged along the wall surface of the steam condensation section 11 on the gas cooling section 14 side, and the other row (the tube row of the cooling water supply pipe 12 on the right side in FIG. 6) being arranged at an equal distance from both of the opposing wall surfaces of the steam condensation section 11.

The spray nozzles 13a to 13c spray cooling water diagonally upstream and downstream at an angle of 45 degrees to the flow direction, and on the opposite side to the gas cooling section 14.

By providing the configuration of the second embodiment described above, the flow rate of the turbine exhaust gas is uniform regardless of whether the turbine exhaust gas passes through the flow passage 22a or 22b formed between the cooling water supply pipe 12. Furthermore, since the arrangement relationship between the flow passage and the cooling water supply pipe is the same for both flow passages 22a and 22b, the amount of cooling water sprayed onto the turbine exhaust gas is more uniform than in the past, and the balance between the amount of cooling water and the amount of turbine exhaust gas can be maintained. Therefore, the turbine exhaust gas is cooled uniformly regardless of which flow passage it passes through, and flow stagnation caused by the cooling state of the turbine exhaust gas or the concentration gradient of non-condensable gas inside the steam condenser 11 can be prevented. As a result, the degree of vacuum inside the condenser 1 can be maintained, and a decrease in the power generation efficiency of the power plant can be prevented.

As a modified example of the second embodiment, as shown in FIG. 7, spray nozzles 13a and 13b may spray cooling water at an angle of 45 degrees to the flow direction in an oblique upstream direction and an oblique downstream direction, and on the opposite side to the gas cooling section 14, and spray nozzle 13c may spray cooling water at an angle of 45 degrees to the flow direction in an oblique upstream direction and a vertical direction, and on the opposite side to the gas cooling section 14.

As another variation of the second embodiment, for example, as shown in FIG. 8, spray nozzle 13a may spray cooling water diagonally upstream and downstream at an angle of 45 degrees to the flow direction, and on the opposite side to the gas cooling section 14, while spray nozzles 13b and 13c may spray cooling water diagonally upstream and vertically at an angle of 45 degrees to the flow direction, and on the opposite side to the gas cooling section 14.

According to each of the modified examples of the second embodiment shown in FIG. 7 or FIG. 8, in addition to the same effects as the second example, the spray nozzle 13b or 13c sprays the cooling water diagonally upstream or perpendicular to the flow direction of the cooling water, thereby lengthening the heat exchange time between the turbine exhaust gas and the cooling water, and improving the cooling performance of the steam condenser 11. Therefore, the degree of vacuum inside the condenser 1 can be maintained, and the space in the height direction of the condenser 1 can be reduced.

In the second embodiment or its modified example, when spraying cooling water from spray nozzles 13a to 13c in a diagonal upstream or downstream direction relative to the flow direction, it is sufficient to spray cooling water in a diagonal upstream or downstream direction relative to the flow direction, and it is not necessary to spray cooling water in a diagonal upstream or downstream direction at an angle of 45 degrees relative to the flow direction.

Third Embodiment
Next, a direct contact condenser according to a third embodiment will be described with reference to the drawings. In the following description, only the differences from the above-mentioned respective embodiments and their modified examples will be described, and the same reference numerals will be used to designate the same parts as those in the first and second embodiments and their modified examples, and detailed description thereof will be omitted.

The difference between this embodiment and each of the above-mentioned embodiments and their modified examples is the arrangement of the cooling water supply pipe 12 and the direction in which the spray nozzles 13a to 13c spray the cooling water.

As shown in FIG. 9, the cooling water supply pipe 12 according to this embodiment forms a flow path 23 inside the steam condensation section 11. The cooling water supply pipe 12 is arranged in two rows and three columns, with one row (the row of cooling water supply pipes 12 on the left side in FIG. 9) arranged along the wall surface of the steam condensation section 11 on the gas cooling section 14 side, and the other row (the row of cooling water supply pipes 12 on the right side in FIG. 9) arranged along the wall surface of the steam condensation section 11 on the opposite side.

Spray nozzles 13a to 13c spray cooling water diagonally upstream and downstream at an angle of 45 degrees to the flow direction, toward the flow path 23.

By providing the configuration of the third embodiment described above, when the turbine exhaust gas passes through one flow path formed between the cooling water supply pipes 12, the cooling water is sprayed symmetrically, so that not only is the flow rate of the turbine exhaust gas passing through the flow path 23 more uniform than before, but the amount of cooling water sprayed into the flow path 23 is more uniform than before, and a balance between the amount of cooling water and the amount of turbine exhaust gas can be maintained. As a result, the turbine exhaust gas is cooled uniformly, and it is possible to prevent flow stagnation inside the steam condensation section 11 due to the cooling state of the turbine exhaust gas or the concentration gradient of non-condensable gas. As a result, the degree of vacuum inside the condenser 1 can be maintained, and a decrease in the power generation efficiency of the power plant can be prevented.

As a modified example of the third embodiment, for example, as shown in FIG. 10, spray nozzles 13a and 13b may spray cooling water diagonally upstream and downstream at an angle of 45 degrees to the flow direction toward the flow path 23, and spray nozzle 13c may spray cooling water diagonally upstream and vertically at an angle of 45 degrees to the flow direction toward the flow path 23.

As a modified example of the third embodiment, for example, as shown in FIG. 11, spray nozzle 13a may spray cooling water toward flow path 23 in an oblique upstream direction and downstream direction at an angle of 45 degrees to the flow direction, and spray nozzles 13b and 13c may spray cooling water toward flow path 23 in an oblique upstream direction and vertical direction at an angle of 45 degrees to the flow direction.

According to each of the modified examples of the third embodiment shown in FIG. 10 or FIG. 11, in addition to the same effects as the third embodiment, the spray nozzle 13b or 13c sprays the cooling water diagonally upstream or perpendicular to the flow direction of the cooling water, thereby lengthening the heat exchange time between the turbine exhaust gas and the cooling water, and improving the cooling performance of the steam condenser 11. Therefore, the degree of vacuum inside the condenser 1 can be maintained, and the space in the height direction of the condenser 1 can be reduced.

In the third embodiment or its modified example, when spraying cooling water from spray nozzles 13a to 13c in a diagonally upstream or downstream direction relative to the flow direction, it is sufficient to spray cooling water in a diagonally upstream or downstream direction relative to the flow direction, and it is not necessary to spray cooling water in a diagonally upstream or downstream direction at an angle of 45 degrees relative to the flow direction.

Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the scope of the invention and its equivalents described in the claims.

1... Condenser, 10... Turbine exhaust duct, 11... Steam condensation section, 12... Cooling water supply pipe, 13a, 13b, 13c... Spray nozzle, 14... Gas cooling section, 15... Gas exhaust port, 16... Filler, 17... Hot well, 21a, 21b, 21c, 22a, 22b, 23... Flow path, 30... Geothermal power plant, 31... Gas-liquid separator, 32... Dehumidifier, 33... Steam turbine, 34... Generator

Claims (7)

A downward exhaust type condenser in which a cooling water supply pipe is provided inside a steam condensation section into which turbine exhaust gas flows,
a plurality of spray nozzles provided in the cooling water supply pipe and arranged in a flow direction of the turbine exhaust gas;
Of the multiple spray nozzles, the spray nozzle located most downstream in the flow direction of the turbine exhaust gas is a direct contact condenser that sprays cooling water in an oblique upstream direction or perpendicular to the flow direction of the turbine exhaust gas. 2. The direct contact condenser according to claim 1, wherein, among the plurality of spray nozzles, the spray nozzle arranged most upstream with respect to the flow direction of the turbine exhaust gas sprays cooling water in a diagonal upstream direction with respect to the flow direction of the turbine exhaust gas. 3. A direct contact condenser according to claim 1, wherein the spray nozzles other than the spray nozzle provided in the cooling water supply pipe arranged most upstream in the flow direction of the turbine exhaust gas spray the cooling water in a diagonally upstream direction or perpendicular to the flow direction of the turbine exhaust gas. A direct contact condenser according to any one of claims 1 to 3, in which the rows of the multiple spray nozzles are arranged in parallel in a direction perpendicular to the flow direction of the turbine exhaust gas. The direct contact condenser according to claim 4, wherein adjacent rows of spray nozzles are equally spaced. The direct contact condenser according to claim 4, wherein one of the rows of spray nozzles is arranged along the wall surface of the steam condensation section, and the other row is arranged at an equal distance from the opposing wall surface of the steam condensation section. 5. The direct contact condenser according to claim 4, wherein one of the rows of spray nozzles is arranged along a wall surface of the steam condensation section, and the other row is arranged along a wall surface opposite to the wall surface.

Images