JPS6251513A - Moisture condensation preventive method and power plant executing said method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a method for preventing condensation of moisture in pipes and containers of a particulate material empty transport device. The invention further relates to a conveying device implementing the method.

The invention is useful, for example, for delivering crushed coal or sulfur absorbent to a pressurized combustion chamber carrying out combustion in a fluidized bed, or for delivering ash or other dust from a gas cleaner. Applicable to crushed solid material conveying equipment.

8. Problems to be Solved by the Invention At acid operating conditions, the temperature of the carrier gas, or the temperature of the walls of the transport pipe or container, becomes lower than the dew point of, for example, water vapor or acid in the carrier gas. In such cases, the water vapor condenses in the form of droplets within the carrier gas or on the cold surfaces of pipes or vessels. Such moisture condensation usually occurs locally. When moisture condensation occurs, solid particles, especially finely divided particles, adhere to and accumulate on the condensed water droplets and on the wet wall surface. This deposit is
It becomes thicker until the wall surface temperature reaches or exceeds the dew point. Such deposits become a major problem because they clog pipes.

The conditions under which the blockage occurs occur when a PFBC (pressurized fluidized bed combustion) power plant is started from a cold state. By heating all major parts of the plant to a temperature above the dew point of the water vapor in the carrier gas, the risk of moisture condensation can be avoided.

However, it is difficult to heat all the areas where there is a risk of moisture condensation, such as corners, corners, or other areas of large wall thickness.

According to the invention, the conveying device is supplied with energy in the form of electromagnetic waves, preferably in the microwave range, which eliminates water droplets in the carrier gas and the walls of pipes and containers. The water condensed on top is heated and evaporated.

This evaporation is achieved by dielectric heating of the water droplets and moisture.

The amount of microwave absorption is proportional to the dielectric constant of the material, and the higher the constant value, the greater the absorption amount. Since liquids, such as water, have a high dielectric constant ε, microwave energy is mainly absorbed by water droplets and condensed water. The metal surfaces of pipes and containers are electrical conductors and reflect microwaves.

The amount of energy absorbed there is extremely small. Microwaves propagate to all parts of space. Therefore, water droplets and condensed water are heated and evaporated wherever they are. Heating energy is delivered to the right places and is fully utilized.

The absorbed energy is expressed by the following equation.

-f-Fr where f- at frequency = relative dielectric constant = ε/ε0 ε. = dielectric constant in the space Therefore, in order to obtain a good effect, it is better to choose a high frequency. With established heating technology, 1~30Gt-1z (
Frequencies in the range of about 1 to 30 att are used.

The appropriate frequency for heating in the present invention is that of the node σU.

2. Embodiment FIG. 1 shows a pipe 1 for transporting a powdered material 2, to which a microwave generator 3 is connected via a pipe 4. Plate 5 that transmits microwaves
, for example a glass plate is mounted within the tube 4. This plate 5 is necessary to prevent contaminants from entering the microwave generator 3. Also, when pipes and vessels are under high pressure, for example in PFBC plants,
Plate 5 acts as a pressure barrier.

In FIG. 2, 11 is a pressure tank, 12 is a combustion chamber, and 13 is a cyclone type cleaner. Combustion chamber 12 and cleaner 13 are housed within pressure tank 11 . Although only one cleaner 13 is shown in the drawings, in reality a cleaner plant is provided consisting of a plurality of parallel groups of cyclones 13 connected in series. Combustion chamber 12
Fuel is combusted in a fluidized bed 14 inside and the combustion gases are collected in a freeboard 15 and from there flow through a pipe 16 to a cleaner 13 where they are cleared of dust and then into a pipe. 17 to the turbine 18. This turbine 18 drives compression l119. This turbine-compressor unit 18 , 19 is connected by a coupling 29 to a starter motor 20 . Alternatively, a generator permanently connected to the turbine-compressor unit 18.19 can be used as the starting motor.

Combustion air compressed by the compressor 19 is sent through a pipe 21 to a space 22 within the pressure vessel 11 . This combustion air flows from the space 22 to the nozzle 23 in the bottom 24 of the combustion chamber 12.
and into the combustion chamber 12 to fluidize the material within the bed 14. Inside the bed 14 is a tube bundle 25 in which steam is produced, which drives a steam turbine (not shown). The tube bundle 25 is also the bed 14
to cool down. The dust separated in the cyclone 13 is sent through a pipe 26 to a dust discharge device 27 where it is cooled. This dust ejector is cooled by the combustion air flowing in the shaft 28 to the nozzle 23. The dust is sent through pipe 30 to a collection tank (not shown).

Fuel supply to the combustion chamber 12 is carried out by a pneumatic conveying device 31. This conveying device 31 is a booster compressor t of the carrier gas.
It is equipped with 132. The inlet side of this booster compressor 32 is connected to the space 22 in the pressure tank 11 , and the outlet side is connected to a transport pipe 33 for delivering fuel to the bed 14 .

The conveying device 31 furthermore comprises a lock hopper device comprising one initial atmospheric container 34 and two sluice containers 35, 36 connected in series with each other.

Vibrators 37 and 38 between the containers 34, 35, and 36 are provided with control valves 37 and 38, respectively.

A delivery vibrator 42 from the container 36 is equipped with a rotary feeder 43 driven by a motor 44 . Vibrator 42 and 33
Upstream of the connection point 45 , a restriction in the form of a nozzle 46 is provided. This nozzle 46 is preferably a Laval
) type. When a Laval type nozzle is used, if the pressure behind the nozzle 46 is at least 5% lower than the pressure in front of it, the velocity of the carrier gas in the pipe 33 will substantially decrease regardless of the pressure behind the nozzle 46. constant. If other types of throttling devices are used, a larger pressure difference and more compressor work are required to maintain a constant velocity of the carrier gas in the vibrator 33 at varying pressures behind the nozzle 46. It is.

Microwave generators can be provided for various components within the plant. Therefore, the microwave generator 50 is connected to the vibrator 51.
is coupled to the coal or absorbent transport vibe 33 by. A microwave generator 52 is connected to the combustion chamber 1 by a vibrator 53.
2 and opens into the freeboard 15. The microwave travels forward from the freeboard 15 and passes through the pipe 16.
It is possible to proceed through the cyclone 13 and further to the pipe 17 and the ash discharge device 27. A microwave generator 54 may also be coupled to one or more dust separators 13 by a vibrator 55 .

The microwaves pass through the cyclone 13 and the pipe 17 to the turbine 18 to prevent moisture condensation and dust accumulation within the turbine. Furthermore, it is preferred to connect a microwave generator 56 to the bend of the dust transporting vibrator 26 by means of a pipe 57. This bonding mode is shown enlarged in FIG.

The vibrator 57 includes a window 58 that transmits microwaves.

[Brief explanation of the drawing]

FIG. 1 schematically shows the invention, FIG. 2 shows the invention applied to a power plant in which fuel is burned in a pressurized fluidized bed, a so-called PFBC plant, and FIG. 2 shows a mode of coupling the microwave generator to the transport vibe of the plant of FIG. 11... Pressure tank, 12... Combustion chamber, 13... Cleaner, 18... Turbine, 26... Dust transport pipe, 27 ...Dust release device, 3.1...Fuel transport device, 33...Fuel transport vibrator, 50.52.54.56...Microwave generation Vessel, 58...window.

Claims (3)

[Claims] (1) Pneumatic transport pipes (26, 33), containers (12, 13), and other components (
18) A method of preventing the condensation of moisture in said pipes (26, 33), containers (12, 13), by applying energy in the form of microwaves to evaporate the water that forms at the dew point and the water that condenses on the surfaces. A method characterized in that it supplies other ingredients (18). (2) Containers (12, 13), pneumatic transport pipes (26, 3)
3) In a PFBC power plant comprising other components (18), to prevent condensation of moisture in the containers (12, 13), pneumatic transport pipes (26, 33), and other components (18), A power plant characterized in that a microwave generator (50, 52, 54, 56) is coupled to one or more of the components. (3) In the power plant according to claim 2, the pipes (26, 33), containers (12, 13), other components (18) and the microwave generator (50, 52,
54, 56) and a plate that transmits microwaves (
58) A power plant characterized by comprising: