JP5533756B2 - Geothermal hot water treatment equipment - Google Patents

Description

  The present invention relates to a geothermal hot water treatment apparatus, and more particularly to a geothermal hot water treatment apparatus suitable for application when appropriately treating hot water produced together with steam from a geothermal steam production well used for geothermal power generation.

  In the geothermal power plant, when the hot water flowing out from the geothermal production well is treated, the silica component contained in the hot water is deposited, and adheres as a scale in the pipe and is blocked.

  In order to suppress such precipitation of the silica component, for example, an inorganic acid such as sulfuric acid or nitric acid is added to lower the pH. When adjusting the pH, the acid corrosion of the equipment becomes a problem if the pH is lowered too much. Therefore, the addition amount of the acid is determined in consideration of the effect of suppressing the precipitation of the silica component and the corrosion resistance of the equipment material.

  However, since the amount of addition is determined assuming the acid concentration (or pH) when the added acid is completely mixed, the inner wall surface of the pipe remains at a high concentration without sufficient mixing of the added acid. And reaching the surface of the equipment will result in acid corrosion problems. Therefore, for example, when an acid is injected into a pipe, a supply port is generally provided at the center of the pipe and is allowed to flow out in the axial direction of the pipe.

  For example, in Patent Documents 1 and 2, as shown in FIG. 1, the geothermal steam and hot water produced from the production well 1 are supplied to the steam separator 3 via the pipe 2. After being separated into geothermal steam and hot water, the geothermal steam is taken out from the pipe 4 and supplied to a turbine (not shown), and the hot water is supplied to the heat exchanger 7 through the level headers L and H. In a geothermal steam production facility that is used as a heat source for heating or the like and then returned to the underground from the reduction well 8, an acid container is provided in the hot water pipe 5 separated by the steam / water separator 3. 6 discloses a technique for adjusting pH by directly injecting acid.

JP-A-57-51393 (FIG. 1) JP-A-10-205266 (FIGS. 1 and 2)

  However, usually, when acid is added to water, heat of dilution is generated. In addition, since various components are dissolved in the geothermal hot water, the acid may react with the components to generate reaction heat.

  In general, since the hot water separated from the steam separator 3 is almost in the state of gas-liquid saturation at a temperature slightly lower than the boiling point, the amount of heat generated is particularly high due to the heat of dilution and heat of reaction when the acid is injected. In the vicinity of the mixed interface between a large acid solution and hot water, the hot water temperature reaches the boiling point, and it is boiled and water vapor bubbles are easily generated. Since the generated water vapor bubbles are subjected to a force vertically upward in the pipe due to buoyancy, the opening of the acid supply pipe 14 is accompanied by the generated water vapor bubbles B as shown in FIG. The acid solution A injected from the portion 14A moves upward, the high concentration acid solution A reaches the inner wall of the top of the pipe 5, and the surface thereof is corroded.

  In order to avoid this problem, it is conceivable to supply acid to the vertical pipe instead of the horizontal pipe, but in this case, it is difficult to secure a long pipe length before and after the injection part due to the height restriction on the equipment. Since there are many cases, bent pipes such as elbows are likely to be disposed upstream and downstream near the injection portion. In this case, as shown in FIG. 3 where there is a bent pipe 11 on the downstream side of the injection part (upward in the figure), a drift C in which the flowing direction of hot water deviates from the center of the pipe is generated at the bent part. Therefore, it becomes easy for a high concentration acid solution to reach the bent pipe inner wall, and the same concern arises. This is the same even when there is a bent pipe 11 on the upstream side of the injection part (downward in the figure) as shown in FIG.

  The present invention has been made to solve the above-mentioned conventional problems. Even when hot water is supplied through a horizontal pipe, it is possible to inject acid into the hot water and mix it evenly. It is an object of the present invention to provide a geothermal hot water treatment apparatus that can reliably prevent the inner wall surface of a pipe from being corroded.

The present invention relates to a geothermal hot water treatment apparatus for supplying hot water produced together with steam from a geothermal production well from steam with a steam separator, and then supplying it downstream through the pipe. A guide pipe having a smaller diameter is provided along the axial direction, and an opening of an acid supply pipe for injecting acid into the hot water flowing in the pipe is provided inside the peripheral edge near the upstream end of the guide pipe. The guide tube is set to a length that disappears while the water vapor bubbles generated by the heat generated by the acid injected from the opening of the acid supply tube move with the hot water, It solves the problem.

Here, the guide pipe can be arranged coaxially with the pipe.

  Further, the guide tube can be formed of a corrosion resistant material.

  Furthermore, the opening of the acid supply pipe can be located in the guide pipe.

  According to the present invention, a guide pipe having a smaller diameter than the pipe is disposed in the pipe through which the hot water is circulated along the axial direction, and from the opening disposed inside the peripheral edge near the upstream end of the guide pipe. Since the acid can be injected, the injected acid flows along with the hot water in the guide tube. As a result, the hot water boils due to heat generated by the acid mixing, and water vapor bubbles are generated. Even so, since the high-concentration acid can be prevented from reaching the inner wall of the main pipe as the water vapor bubbles rise, the inner wall of the ceiling is reliably prevented from being corroded by the acid. Can do.

Schematic diagram showing the outline of a conventional geothermal steam production well Cross-sectional view showing conventional problems Sectional view showing other conventional problems Sectional view showing still another problem of the prior art Sectional drawing which shows the principal part of 1st embodiment of the geothermal hot water processing apparatus which concerns on this invention. Diagram showing the operation of the first embodiment Sectional drawing which shows the principal part of 2nd embodiment of the geothermal hot water processing apparatus which concerns on this invention. Sectional drawing which shows the principal part of 3rd embodiment of the geothermal hot water processing apparatus which concerns on this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 5 is a schematic explanatory view showing the main part of the first embodiment of the geothermal hot water treatment apparatus according to the present invention together with the action.

  The geothermal hot water treatment apparatus of the present embodiment is for supplying hot water produced together with steam from a geothermal production well from steam using a steam separator and then supplying it downstream through a pipe.

  In the case of the production facility of FIG. 1, it is applied to a joining position of hot water flowing in the pipe 5 downstream from the steam separator 3 and an acid injected from an acid supply pipe connected to the acid container 6. Is done.

  In the present embodiment, a guide pipe 12 having a smaller diameter than the main pipe 10 is disposed along the axial direction inside the main pipe 10 corresponding to the pipe 5, and the peripheral edge portion in the vicinity of the upstream end 12 </ b> A of the guide pipe 12. An opening 14A of an acid supply pipe 14 for injecting acid into the hot water H flowing through the main pipe 10 is disposed on the inner side and slightly downstream of the upstream end 12A.

  Since the opening 14A has a structure extending to the inside of the guide tube 12, even when the water vapor bubble B rises directly above, the rise can be reliably prevented.

  The guide tube 12 is a cylindrical straight tube made of a corrosion-resistant material such as a stainless steel tube, a fluororesin tube, or a fluororesin coating tube, and its axis is arranged substantially coaxially with the main pipe 10.

  The guide tube 12 has a length that disappears while the water vapor bubbles B generated by the heat generated by the acid injected from the opening 14A of the acid supply tube 14 move with the hot water H, for example, a guide. When the diameter of the tube is D, it is set to about 2D to 5D.

  Next, the operation of this embodiment will be described.

  As described above, the guide pipe 12 is disposed substantially coaxially with the main pipe 10, and a part of the hot water H flowing through the main pipe 10 always flows in the guide pipe from the upstream end 12 </ b> A of the guide pipe 12. It is like that.

  The acid solution A supplied from the acid supply pipe 14 flows into the guide pipe 12 along with the flow of the hot water H, and comes into contact with and mixes with the hot water H flowing through the guide pipe 12. During this mixing, heat of dilution and heat of reaction are generated, and hot water H is boiled to produce water vapor bubbles B.

  Since this steam bubble B has a vertically upward flow velocity component due to buoyancy, it rises with a high concentration of acid solution. However, since the rise is restricted by the guide tube 12, the guide tube 12 Will flow inside.

  At this time, since the guide tube 12 is made of a material having acid corrosion resistance, the problem of corrosion does not occur.

  Moreover, since the generated water vapor bubbles B are condensed by contacting with hot water having a temperature slightly lower than the boiling point as it flows through the guide tube 12, the bubble diameter gradually decreases and eventually disappears. . Therefore, the mixed solution of hot water and acid solution flows out from the downstream end 12B of the guide tube 12 in a state where at least the large water vapor bubbles B are surely disappeared. More preferably, in the hot water flowing out from the downstream end 12B of the guide tube 12, it is desirable that all the steam bubbles B have disappeared. Under general geothermal hot water conditions, the above condition is achieved by setting the length of the guide tube 12 to about 2 to 5 times its diameter.

  The liquid mixture flowing out from the guide tube 12 does not have to be completely uniformly mixed, and may have a certain concentration distribution. The mixed solution flowing out from the guide tube 12 flows while mixing with hot water (acid concentration zero) flowing outside the guide tube 12, but since the water vapor bubbles B have disappeared, there is no guide tube. However, there will be no vertical upward buoyancy. By disposing the downstream end 12B of the guide pipe 12 in the vicinity of the approximate central axis of the main pipe 10, in the main pipe 10 downstream of the guide pipe 12, as shown in FIG. Thus, the concentration distribution is maintained such that the concentration of the acid solution decreases toward the periphery. Therefore, it flows while mixing with the hot water H that has flowed outside the guide tube 12 in a substantially concentric manner while maintaining a high concentration in the central portion and a low concentration in the peripheral portion. In FIG. 6, R is the radius of the main pipe 10. As shown in FIG. 6, the inner wall of the main pipe 10 downstream from the guide pipe 12 is always in contact with the acid solution having the lowest concentration in the normal section of the pipe axis, and complete mixing is achieved. Therefore, it is possible to reliably prevent the top wall of the main pipe 10 from being corroded by the high concentration acid solution.

  In the present embodiment, since the guide tube 12 is constituted by a cylindrical straight tube, it is easy to manufacture and inexpensive. However, the shape of the guide tube is not limited to a cylindrical straight tube. For example, a rectangular tube may be used.

  In FIG. 7, the principal part of 2nd embodiment which concerns on this invention is shown.

  In this embodiment, the guide tube 12 is an enlarged taper tube whose diameter is increased toward the downstream, and other configurations are the same as those in the first embodiment.

  As described above, by adopting an enlarged taper tube as the guide tube 12, an effect of promoting diffusion mixing can be obtained, and therefore, mixing of acid and hot water can be efficiently promoted particularly on the downstream side of the guide tube. .

  In FIG. 8, the principal part of 3rd embodiment which concerns on this invention is shown.

  In the present embodiment, the guide tube 12 is a reduced taper tube having a smaller diameter toward the downstream, and the other configuration is the same as that of the first embodiment.

  In this way, by adopting a reduced taper tube as the guide tube, the mixing promotion effect can be obtained in the same manner, and the direction of the flow in the guide tube 12 and the direction of the buoyancy acting on the water vapor bubbles B are reversed. The water vapor bubbles B easily stay in the guide tube 12, and an effect of promoting defoaming can be obtained compared to the case of a straight tube.

  In the above embodiment, the acid supply pipe 14 is connected to the downstream side of the level headers L and H. However, the position where the acid supply pipe 14 is connected is not limited thereto. As shown in FIG. 1 of Document 2, upstream of the level headers L and H in the main pipe, or as shown in FIG. 2 of Patent Document 2, to the main pipe upstream of the steam / water separator 3. A pipe for returning hot water may be used.

  Moreover, although the example in which the horizontally arranged main pipe 10 and the guide pipe 12 are coaxially arranged has been shown, the present invention is not limited to this, and for example, even if inclined upward toward the downstream, It may be inclined downward.

  Further, the main pipe 10 is not limited to the horizontal arrangement, but may be a vertical arrangement. In this case as well, the main pipe 10 is generated by the bent pipe 11 such as the elbow on the upstream side (lower side in FIG. 4) as shown in FIG. The influence of the drift C in the acid injection part can be suppressed by the guide tube.

DESCRIPTION OF SYMBOLS 10 ... Main piping 12 ... Guide pipe 12A ... Upstream end 12B ... Downstream end 14 ... Acid supply pipe 14A ... Opening

Claims (4)

In the geothermal hot water treatment device that supplies hot water produced together with steam from the geothermal production well from the steam by the steam separator, and supplies it downstream through the piping,
Inside the pipe, a guide pipe having a smaller diameter than the pipe is disposed along the axial direction,
The on the periphery inside the upstream end near the guide tube, the opening of the acid supply tube for injecting an acid into hot water flowing in the pipe is arranged Rutotomoni,
The guide tube is set to a length that disappears while water vapor bubbles generated by heat generated by the acid injected from the opening of the acid supply tube move with the hot water. Geothermal hot water treatment equipment. The geothermal hot water treatment apparatus according to claim 1, wherein the guide pipe is disposed coaxially with the pipe. The geothermal hot water treatment apparatus according to claim 1 or 2 , wherein the guide tube is made of a corrosion-resistant material. The geothermal hot water treatment apparatus according to any one of claims 1 to 3 , wherein an opening of the acid supply pipe is located in the guide pipe.

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