JPS62288800A - Dust removing apparatus for natural steam - Google Patents

Abstract

PURPOSE:To remove the dust with high efficiency by utilizing a condensed steam for producing a mist in a conduit and catching micro particle dust by means of said mist. CONSTITUTION:Natural steam taken from a steam well 1 is cooled through a cooler 3 arranged in the way of a conduit 2 and a portion thereof is condensed into water which is fed with high speed through the conduit together with the steam. When passing through a projection 4 provided in the downstream, said water is fed with a higher speed because the diameter of the conduit 2 is restricted near the projection 4 and dispersed in mist into the conduit. Consequently, the dust contained in the steam is caught onto the surface of the mist drip. Furthermore, the mist is separated from the steam through a mist separator 5 thereby only a clean steam is fed through the conduit 2 to a turbine 6.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an apparatus for removing dust from natural steam in a natural steam type geothermal power generation plant or the like.

[Conventional technology]

Many types of geothermal power generation plants have been put into practical use depending on the characteristics of geothermal wells, but among them, underground natural steam is used as a method that uses simple above-ground equipment and can generate power at low cost. The method used is well known.

This natural steam type geothermal power generation plant uses high-temperature, high-pressure natural steam extracted from an underground steam well as the steam for power generation. Such natural steam cannot be directly fed into the turbine as it is because it contains a large amount of dust, and this fine dust causes scaling on the surfaces of turbine blades and shrouds, causing a reduction in turbine output.

For this reason, conventionally, as shown in Figure 4, the steam well (7)
The steam taken out from the steam pipe (8) is sent to a dry separator (9) such as a cyclone separator or an inertia separator to separate and remove dust contained in the steam, and then to the turbine αO. The method was to send them in.

However, with such dry separators, the particle size of the dust that can be collected is 20 to 30 μ or more for a cyclone separator that uses centrifugal force, and 10 μ or more for an inertial force separator that uses inertial force, and the collection efficiency is also low. Low level of 60-70. Therefore, a large amount of fine dust still remains in the steam that has passed through such a dry separator, which causes scaling of the turbine and reduces the turbine output. The reduction in output due to the influence of dust extends to about 104 times per month at the power plants.

In contrast to such a dry separator, a one-type wet scrubber is known as a method that can appropriately remove fine dust from several microns to several tens of microns, and it is considered that this method can be applied to dust collection from natural steam. It will be done. In this method, water flows into a fluid containing dust, the water collects fine dust, and the dust is separated and removed from the fluid along with the water.
A collection efficiency of 95 or more can be expected.

[Problem that the invention seeks to solve]

However, when this wet scrubber is applied to a natural steam type geothermal power generation plant, there is a major problem in that the equipment is rapidly corroded by the dissolved oxygen in the injected water.

That is, oxygen may be mixed into the heated fluid.

As has been reported in many geothermal plants,
In pipe equipment made of carbon steel, general corrosion accelerates more than ten times as much as in the case where there is no oxygen contamination7, resulting in an extremely shortened service life of the equipment. This is because the oxygen dissolved in the injected water oxidizes the sulfide water contained in the natural steam to produce sulfur and sulfuric acid, which wash the inside surfaces of pipes, etc. This is due to the fact that 1 iron is washed away and 8 lines of corrosion occur. In addition, oxygen contamination can cause partial corrosion due to local battery formation, and if the tube is made of stainless steel, it can also cause pitting corrosion due to hydrochloric acid generated by the reaction between oxygen and chlorine ions.

Therefore, when trying to apply a wet scrubber to a geothermal power plant, it is necessary to remove oxygen dissolved in the injected water, but this requires a high-performance deaerator as ancillary equipment, which would actually require large equipment. It makes things complicated and complex.

The present invention was developed in view of the conventional problems described above, and it is possible to remove fine dust from steam and air using simple equipment without causing the problem of corrosion of pipe equipment such as wet scrubbers. The purpose is to provide a device that can remove the waste efficiently.

[Means to solve the problem]

For this reason, the device of the present invention is provided with a cooling section in the middle of the steam pipe line for condensing a part of the steam flowing inside the pipe, and inside the pipe downstream thereof, narrows the gap and increases the flow velocity of the steam. The feature is that a protrusion is provided to disperse the condensed water as mist, and a mist separator is further provided in the steam pipe downstream of the protrusion to separate the steam and the mist that collects dust.

[For production]

Natural steam taken out from a steam well or the like is cooled in a cooling section installed in the middle of a steam pipe, and a portion of it condenses to become water. This condensed water is conveyed through the tube at a high flow rate by the steam, and the flow rate is further increased by a protrusion provided downstream of the cooling section, thereby dispersing it in the form of a mist inside the tube. Dust in the steam is collected on the surface of the droplets of this mist. The mist containing this dust is then separated and removed from the steam by a mist separator installed on the downstream side.
As a result, only 79 clean steam is supplied to the turbine.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

In the figure, (1) is a steam well, (6) is a turbine, and (2) is a steam well.
) is the turbine (6) that uses the natural steam extracted from this steam well.
It is a conduit for serving and @.

A cooler (3) is provided in the middle of the pipe (2). The cooler (3) is for cooling the steam in the pipe (2) and condensing a part of it, and has a structure in which the steam in the pipe (2) is cooled by cooling fluid such as cooling water. It becomes. Although a cooler is used as the cooling unit in this embodiment, a structure may also be used in which steam naturally radiates heat and the residual air is condensed. In other words, the pipe (2) is generally kept warm by wrapping a heat insulating material around the pipe to maintain the high temperature of the steam, but if there is sufficient steam output from the production well,
Remove the heat insulation material, etc. over a certain section of W road (2),
It is also possible to construct this part as a cooling part and obtain condensed water by promoting heat radiation from the pipe (21).

A protrusion (4) is provided on the inner surface of the tube downstream of the cooler. The protrusion (4) narrows the pipe diameter and increases the flow rate of steam, thereby converting condensed water in the steam into a mist (A) inside the pipe.
), and in this embodiment, it is composed of an annular plate-shaped body provided along the inner periphery of the tube.

This plate-shaped body is provided with a certain slope in the downstream direction of the pipe in order to smooth the flow of steam.

A mist separator (5) is provided in the conduit (2) further downstream of the projection (4). The mist separator (5) is for separating and removing the mist that has collected dust from the steam. Examples of this mist separator include a structure that collides mist with a conventionally known baffle plate and separates it from steam as a drain.
A material having an appropriate structure can be used.

Next, to explain the operation of this embodiment, the natural steam taken out from the steam well (1) is cooled by the cooler (3) in the middle of the pipe (2), and a part of it condenses and becomes water. It is sent through the pipe at a high flow rate along with steam. When this condensed water passes through the protrusion (4) provided downstream of the cooler (3), the flow rate is further increased because the pipe 1 in this part is narrowed, and it is dispersed in the form of a mist within the pipe. do. By turning the condensed water into a mist, dust contained in the steam is collected on the surface of the mist droplets. Then, the mist that has collected four pieces of dust is separated and removed from the steam in the mist separator (5), and only clean steam is supplied to the turbine (6) via the pipe (2). Note that the cooler (
By using the heat of the steam recovered in step 3) as a heat source for multi-purpose facilities, the energy utilization rate can be improved.

In the device of the present invention as described above, the dust in the steam is collected on the surface of the mist droplets, and the separation efficiency at the mist separator increases, so that clean steam with a dryness level of 99.994 or higher can be obtained. Can be done.

In addition, in the present invention, the energy retained in the steam is reduced by cooling by the cooling section, and the amount of steam is reduced when a part of the steam is condensed to obtain water for mist formation, so that it can be used in a turbine. Although the retained energy of the steam will decrease, the rated steam amount of the turbine can be secured by increasing the steam production to match the amount of mist separated by the mist separator.

〔Effect of the invention〕

According to the present invention described above, a mist is generated in a pipe by using condensed water of steam without injecting water from the outside, and fine dust in the steam can be appropriately collected by this mist. As a result, it is possible to remove fine dust from steam with high collection efficiency without causing the problem of corrosion of pipe equipment due to dissolved oxygen in the injected water, which is the case with conventional wet scrubbers. Therefore, it is possible to suppress the occurrence of scaling caused by dust J, and to operate the turbine stably for a long period of time.

[Brief explanation of drawings]

1 to 3 show an embodiment of the present invention,
FIG. 1 is an overall explanatory diagram, FIG. 2 is a longitudinal cross-sectional view of the protruding part, and FIG. 3 is a cross-sectional view. FIG. 4 is an overall explanatory diagram of a dry dust removal device in a conventional natural steam type geothermal power generation plant. In the figure, (2) is the steam pipe, (3) is the cooler, and (4
) indicates a protrusion, and (5) indicates a mist separator.

Claims (1)

[Claims] A portion of steam flowing through a steam pipe A cooling section is provided to condense the Inside the downstream pipe, the pipe diameter is narrowed to reduce the steam flow rate. By raising the temperature, condensed water is separated as mist. Protrusions are provided for dispersion, and Steam and dust were collected in the downstream steam line. Mist separator to separate from mist A natural steam dust removal device equipped with a