JPH10220251A - Method of eliminating dust stuck to turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate not only soft stuck dust but also fast-stuck dust by injecting dry ice grains from a plurality of nozzles arranged in an inlet side casing of a turbine toward a first stage stationary blade whole operating the turbine. SOLUTION: When a pressure difference between turbine inlet pressure and pressure after a first stage stationary blade is a control value or more, or a taken gas quantity of a turbine 4 or a power generator output is reduced to constant % while operating the turbine 4, a dry ice injection facility is operated, and dry ice grains are injected from a plurality of nozzles 25 toward a first stage stationary blade 14. The pressure difference between turbine inlet pressure and pressure after first stage stationary blade is recovered within the control value. When the taken gas quantity of the turbine 4 of the power generator output are recovered to near a constant value, operation or the dry ice injection facility is stopped. Such operation is repeated to a next opening inspection. Since stuck dust can be eliminated, it is possible to suppress reduction of the power generating output.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing dust adhering to a stationary blade of a turbine for recovering energy stored in blast furnace gas or the like.

[0002]

2. Description of the Related Art Conventionally, in a blast furnace facility operating at a high pressure, a furnace top pressure turbine is installed in order to recover energy from a high temperature, high pressure blast furnace gas discharged from the blast furnace. By rotating the generator, the energy held by the blast furnace gas is recovered as electricity.

FIG. 2 shows an example of a system diagram for recovering energy stored in a blast furnace gas by a furnace top pressure turbine. The high-temperature, high-pressure gas discharged from the furnace top of the blast furnace 1 is subjected to primary dust removal by a dust catcher 2 and then secondary dust removal by a venturi scrubber 3. The blast furnace gas from which the secondary dust has been removed is rotated by the furnace top pressure turbine 4 and the generator 5, and then subjected to final dust removal by the electric dust collector 7, and the gas holder 8.
to go into. When the blast furnace gas amount exceeds the intake gas amount of the furnace top pressure turbine 4, the pressure regulating valve 6 opens, and the blast furnace gas amount exceeding the intake gas amount passes through the turbine to the electric precipitator 7. Flows.

The blast furnace gas flowing into the furnace top pressure turbine 4 is:
Even after secondary dust removal, it contains about 20 mg / Nm ³ of dust and moisture. For this reason, dust adheres to the stationary blades and the moving blades of the turbine, and grows as the number of operating days elapses. It has been found that the amount of dust attached to the first stage stationary blade is particularly large. In order to reduce the amount of gas swallowed by the turbine and reduce the amount of power generation, the adhesion of dust has to stop the turbine at regular intervals and clean the dust attached to the stationary blades and the moving blades. In order to solve such a problem, a heating fluid is passed through a flow path formed in the stationary blades and moving blades of the turbine, and the temperature of the blade surface is set to a temperature equal to or higher than a temperature at which condensed moisture in gas passing therethrough re-vaporizes. (Japanese Patent Laid-Open No. 62-1572)
09: Technology 1) has been proposed. In addition, a method of injecting water toward a first stage stationary blade from a plurality of water injection nozzles provided in an inlet side casing of a turbine to remove adhering dust (referred to as technology 2) has been implemented.

[0005]

However, the technology 1
In such a method, the flow path for passing the heating fluid through the stationary blade and the moving blade must be processed, and the cost for remodeling is high. In addition, technology 2
Although the soft adhered dust can be removed by water jetting, the hard adhered dust cannot be removed, and there is a problem that the jetted water wets the surfaces of the stationary blades and the moving blades, and the dust is easily attached.

[0006]

The present invention solves the above problems.
The problem is solved by a method for removing adhering dust from a turbine, in which dry ice particles are ejected from a plurality of nozzles provided in a casing on the inlet side of the turbine toward a first stage stationary blade during operation of the turbine to remove adhering dust on the blade.

[Operation] When dry ice particles are injected from a plurality of nozzles into the first stage stationary blades while the turbine is operating, the dry ice particles first collide with the first stage stationary blades, and then, together with the gas flow flowing through the vehicle compartment, It moves at a high speed and collides one after another with the moving blades and stationary blades at the subsequent stage. Due to this collision, the hard dry ice particles remove not only soft adhering dust on the stationary blades and moving blades but also hard adhering dust as in sandblasting.

[0008] Dry ice sublimes while moving in the cabin, but does not wet the surface of the wing unlike water jet, so that dust is less likely to adhere to the wing after dust removal.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory diagram of the method of the present invention. 10 is a turbine casing, 11 is a rotor, 1
2 is a turbine shaft, 13 is a moving blade, and 14 is a stationary blade.

Reference numeral 25 denotes a nozzle provided in the inlet side casing 15 for spraying dry ice particles. A plurality of nozzles 25 are provided around the turbine shaft 12 and are attached so as to spray dry ice particles toward the first stage stationary blades 14.

Reference numeral 20 denotes an apparatus for producing dry ice grains, which produces dry ass particles having a size of 0.5 to 3 mm. 21 is a hopper for storing dry ass particles. 22 is a compressed air source, the pressure of which is 10 to 20 kg
/ Cm ² . 23 is a feeder. In the feeder 23, the dry ice particles in the hopper 21 are mixed into the compressed air, transferred through the pipe 24 by the compressed air, and ejected from the nozzle 25.

The dry ice producing device 20, the compressed air source 22, the hopper 21, the feeder 23, the pipe 24, and the nozzle 25 constitute a dry ice injection device.

Using this dry ice injection device, the method of the present invention is performed as follows. (1) During operation of the turbine, if the pressure difference between the turbine inlet pressure and the pressure after the first stage stationary blade is equal to or greater than the control value, or if the amount of gas taken in by the turbine or the generator output decreases by a certain percentage (for example, 10%), The dry ice injection equipment is operated to inject dry ice particles from the plurality of nozzles 25 toward the first stage stationary blade 14. (2) When the pressure difference between the turbine inlet pressure and the pressure after the first stage stationary blade recovers to within the control value, and the amount of gas swallowed by the turbine or the output of the generator recovers to near the rated value, the operation of the dry ice injection equipment is started. Stop. (3) Repeat (1) and (2) until the next open inspection.

The method of the present invention can be applied not only to a top pressure turbine of a blast furnace but also to an axial compressor or an axial turbine through which gas containing dust passes.

[0015]

According to the present invention, since dust is removed by injecting dry ice particles, the following effects can be obtained. (1) Since solid particles are used, not only softly attached dust but also hardly attached dust can be removed. (2) The dry ice particles are sublimated into carbon dioxide gas and do not wet the wing surface unlike spray water, so that dust hardly adheres to the wing surface. (3) Since the attached dust can be removed during the operation of the turbine, a decrease in the power generation output can be suppressed.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of the method of the present invention.

FIG. 2 is a system diagram in which energy held by blast furnace gas is recovered by a turbine.

[Explanation of symbols]

 Reference Signs List 4 Turbine 5 Generator 10 Turbine casing 11 Rotor 12 Turbine shaft 13 Moving blade 14 Stationary blade 15 Inlet-side casing 20 Dry ice grain production device 21 Hopper 22 Compressed air source 23 Feeder 24 Pipe 25 Nozzle

Claims (1)

[Claims] 1. A method for removing adhering dust on a turbine, comprising injecting dry ice particles from a plurality of nozzles provided in a casing on an inlet side of the turbine toward a first stage stationary blade during operation of the turbine.