RU2534917C2 - Turbine for geothermal power plant - Google Patents

Abstract

FIELD: power industry.

SUBSTANCE: invention relates to heat power industry, and namely to units using heat of geothermal sources in the form of a gas/steam/water mixture with increased salt content. The invention proposes a turbine, the housing, the shaft and the rotating blades of which are hollow and interconnected between each other. Heads of the rotating blades have an oval shape, and thickness of their walls does not exceed thickness of the turbine housing wall. Cold water flowing in the cavity of the turbine housing and the rotating blades reduces temperature of their walls, due to which it is possible to prevent formation of calcium carbonate deposits on the turbine surface.

EFFECT: invention allows increasing energy use efficiency of geothermal sources owing to excluding losses of a mechanical and some thermal potential of geothermal waters, as well as excluding costs for cleaning of a geothermal heat carrier from hardness salts diluted in it.

2 dwg

Description

The invention relates to a power system, in particular, to plants using the heat of geothermal sources in the form of a gas-steam mixture with high salinity.

The presence of a large amount of dissolved salts and gases in geothermal water limits the widespread use of traditional types of turbines at geothermal power plants (GeoTES). Upon reaching the Earth's surface, the partial pressure of carbon dioxide in water decreases. At the same time, in the solution of geothermal water carbon dioxide equilibrium may be disturbed with the formation of the solid phase of calcium carbonate both in the water column in the form of suspended particles, and on the equipment surface in the form of deposits. When using high potential waters (water temperature above 100 ° C), these processes proceed at high speed. Intensive deposits of calcium carbonate are possible in GeoTES expanders and degassers. To eliminate these deposits on the blades of the turbine itself and on its casing, high purification of the geothermal coolant from the dissolved hardness salts contained in it is necessary.

It is known that for a geothermal coolant at any well in the equipment in operation, it is possible to create conditions under which calcium carbonate deposits are not formed in it. This can be achieved by cooling the equipment wall to a temperature below which, at a given pressure, the solid phase of calcium carbonate does not stand out from the solution of geothermal water [1-5].

However, if the wall of the equipment in which the turbine is located, or the wall of the expander, degasser of geothermal water can be protected by cooling it to a temperature below which deposits do not go [5], then the GeoTES turbine can be protected only by preliminary cleaning of the geothermal coolant from hardness salts dissolved in it . At the same time, in the expanders and degassers of GeoTES there is a slight decrease in the mechanical and thermal potential of the geothermal coolant (pressure and temperature of the water decrease). As a result of this, and also because of the cost of cleaning the geothermal coolant from hardness salts dissolved in it, in general, the efficiency of using the energy of the geothermal source is reduced.

The technical problem to which the invention is directed is to increase the efficiency of the use of energy of geothermal sources by eliminating the cost of cleaning the geothermal coolant from hardness salts dissolved in it, as well as eliminating the loss of mechanical and some thermal potential of geothermal waters.

The technical result is achieved by the fact that in a turbine for a geothermal power plant containing a housing on the shaft, working blades and a nozzle for supplying a working fluid, the housing, the shaft and working blades are made hollow and interconnected, while the wall thickness of the working blades does not exceed the wall thickness of the casing and the tops of the shoulder blades have an oval profile.

Figure 1 shows a schematic diagram of the proposed turbine for a geothermal power plant, and figure 2 is a view of figure 1 on aa.

The turbine for a geothermal power plant consists of a hollow body 1 connected at both ends with a shaft 2 in the form of a hollow pipe, working blades 3 in the form of hollow protrusions on the body 1 with an oval profile of the tops 4, a nozzle 5 for supplying the geothermal coolant to the blades 3. the cavity of the housing 1, shaft 2 and rotor blades 3 communicate with each other.

The turbine operates as follows.

The geothermal coolant 6 in the form of a gas-steam mixture is supplied to the working blades 3 through the nozzle 5. Under the action of the pressure forces of the jet of gas-steam mixture, the turbine rotates. Simultaneously, cold water 7 is supplied from one end of the turbine through the shaft 2 to the inside of the housing 1. In this case, cold water 7 fills the turbine housing 1 only to half its capacity. Water 7, passing inside the housing 1, enters the cavity of the blades 3 of the turbine and is discharged from the housing 1 through the opposite end of the turbine along the shaft 2.

The rotation of the turbine and the filling of the capacity of the housing 1 only half intensifies the process of turbulization of the water flow inside the cavity of the housing 1 and the working blades 3. This is also facilitated by the periodic flow of cold water from the housing 1 into the cavity of the blades 3 and vice versa. At the same time, the execution of the walls of the working blades 3 with a thickness of not more than the wall thickness of the housing 1 reduces the thermal resistance of their walls. As a result, all this leads to cooling of the walls of the casing 1 and of the turbine blades 3 from the side of the geothermal coolant to a temperature at which there is no precipitation of the solid phase of calcium carbonate from the solution of geothermal water [1, 2]. An additional condition for cooling the walls of the casing and the blades is the fact that the contact time of cold water with them is longer than the contact time of the gas-vapor mixture. The oval profile of the tops 4 with a wall of not more than the wall thickness of the housing 1 allows you to evenly cool their entire surface.

Thanks to the cooling of the walls of the turbine casing and its blades, the proposed technical solution allows direct supply of the geothermal coolant from the well without intermediate equipment (degassers, expanders), where a loss of some energy potential (pressure, temperature) is possible. At the same time, after passing through the turbine, cold water can be supplied to the secondary circuit of the heat exchanger for further utilization of the heat of the geothermal coolant supplied to the primary circuit of the same heat exchanger. And the utilization of combustible gases from the geothermal coolant can be carried out at any stage after passing through the proposed turbine.

Thus, due to the execution of the casing, shaft and rotor blades in the turbine hollow and interconnected, and the blades with an oval shape of their vertices and walls with a thickness not exceeding the wall thickness of the turbine casing, it is possible to increase the energy efficiency of geothermal sources in the form of a gas-vapor mixture with increased salinity.

Information sources

1. Akhmedov G.Ya. Problems of salt deposition when using geothermal water for hot heat supply // Industrial Energy. - No. 9. - 2009.

2. Akhmedov G.Ya. Protection of geothermal water treatment systems from carbonate deposits // Energy saving and water treatment. - No. 6. - 2010.

3. Akhmedov G.Ya. A device for cleaning liquids. A.S. USSR No. 1583135. MKI B01D 21/24, С02F 5/00. Claim 10.26.88., Published on 07.08.90. Bull. No. 29.

4. Akhmedov G.Ya. Geothermal installation. Patent No. 91384. IPC F03G 7 // 00. Claim 05/04/2008. publ. 02/10/2010. Bull. Number 4.

5. Akhmedov G.Ya. Geothermal device. Patent No. 2406944. IPC F24J 3/08. Claim 04/06/2009., Publ. 12/20/2010. Bull. Number 35.

Claims (1)

A turbine for a geothermal power plant, comprising a housing on the shaft, working blades, a nozzle for supplying a working fluid, characterized in that the housing, shaft and working blades are hollow and interconnected, while the wall thickness of the working blades does not exceed the wall thickness of the housing, and the top the blades have an oval profile.

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