JPH06221514A - Pressure regulating mechanism in discharged particle cooling vessel for circulating fluidized bed device - Google Patents

Abstract

PURPOSE:To permit safe operation of whole of the title device by preventing spouting of particles upon discharging the particles from the bottom of a circulating fluidized bed device into a coling vessel. CONSTITUTION:A pressure regulating mechanism is provided in the discharged particles cooling vessel of a circulating fluidized bed device, constituted of a fluidized bed heat exchanger communicated with the guide-out passage of discharged particles from a fluidized bed forming section. A pressure regulating head is formed of a particles discharging pipe 74, of the discharged particles cooling vessel connected with a seal pipe 75 filled with the particles forming a fluidized bed and an opening degree regulating valve 76, regulating the opening degree of discharging valve positioned at the rear side of the discharging tube 74. According to this method, a pressure in the circulating fluidized bed and a pressure in the discarged particles cooling vessel can be equalized and the particles in the circulating fluidized bed can be discharged smoothly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to discharge of high temperature fluidized bed forming particles in a circulating fluidized bed apparatus in which coal powder is burned in a circulating fluidized bed for heat exchange.

[0002]

2. Description of the Related Art Circulating fluidized bed equipment is capable of desulfurization in a furnace, so that it emits a small amount of SOx, and because it can burn at low temperature, it emits a small amount of NOx, and desulfurization and denitration equipment outside the furnace. It has many fuel advantages such as wide variety of coal that can be used from bituminous coal to semi-anthracite, and the facility itself has excellent reliability. It has come to be widely used as a boiler for power generation. This circulating fluidized bed apparatus itself is disclosed in JP-B-57-28046 and JP-B-59-13.
As described in Japanese Patent No. 644, etc., generally, as shown in FIG. 2, a combustion chamber 1 for burning a fuel mainly composed of powdered fuel, and a particle circulation system including a hot cyclone 2 and a sealing mechanism 3 are provided. , A superheater 4, a economizer 5, and an air preheater 6, and three main parts of a rear convection heat transfer structure.

Then, coal powder, coal ash, and lime powder for desulfurization are introduced into the combustion chamber 1 as circulating particles, and the primary combustion air and the secondary combustion air are discharged from a nozzle installed in two stages in the lower part of the combustion chamber 1.
Secondary air is blown in to form a fluidized bed. After exiting the combustion chamber, the circulating particles are collected by the hot cyclone 2 and recirculated to the combustion chamber 1 via the sealing mechanism 3 formed of a pneumatic valve. On the other hand, the flue gas discharged from the hot cyclone 2 exchanges heat in the convection heat transfer section in the wake after passing through the duct, is dust-collected by the bag filter, and is exhausted from the chimney through the induction fan.

On the other hand, the bottom ash discharged from the bottom of the combustion chamber 1 is cooled in a powder particle cooling container (bottom ash cooler) 7 provided below the bottom of the combustion chamber 1, and then the bottom ash is transported by air. It is transported to the silo 9 by piping.

There are two types of powder particle cooling containers: a mechanical screw conveyor system and a fluidized bed system.

FIG. 3 shows the structure of the screw conveyor system.

As shown in the figure, the screw conveyor 8
Is disposed in the inclined casing 81, and the casing 81 and the screw 82 are cooled by the cooling water introduced from the cooling water inlet 83 for the casing and the cooling water inlet 84 for the screw, respectively. It has become. Reference numeral 85 indicates a cooling water discharge port. The high temperature particles are introduced from the high temperature particle introduction port 86 arranged at the lower position of the conveyor, and the introduced high temperature particles are cooled in the process of being conveyed upward by the screw 82 and discharged from the cooling particle discharge port 87.

In the fluidized bed system, the actual construction of Shokai 62-19201
The method described in Japanese Patent No. 0 is known.

[0009]

However, when the bottom ash is discharged from the bottom of the combustion chamber, a high-density fluidized bed is formed at the bottom of the combustion chamber.
Since it is in a high pressure state of about 00 mm water column, it protrudes when it is discharged into the bottom ash cooler 7 close to normal pressure,
Not only the cooler is damaged, but also the discharge of bottom ash rapidly reduces the number of circulating particles inside the combustion chamber, which makes the circulation itself unstable, making it impossible to maintain the fluid state.

In the conventional structure, a pressure sealing mechanism is provided for pressure sealing from the high pressure portion of the fluidized bed.

For example, in the screw conveyor system of FIG. 3, an intermediate hopper 89 having a pressure seal valve 88 at the inlet and the outlet is provided on the downstream side of the screw conveyor, and the pressure of the intermediate hopper 89 is controlled by the double pressure seal valve 88. By performing uniform discharge pressure, the pressure is sealed and discharged.

It is an object of the present invention to provide a discharged particle cooling container which prevents the bottom ash from protruding when discharging the bottom ash from the circulating fluidized bed device to the cooling container and enables stable operation of the entire device. It is in.

[0013]

According to the present invention, a circulating fluidized bed is constructed as a fluidized bed heat exchanger that communicates with a discharge particle discharge passage from a fluidized bed forming section, and a discharge particle cooling container is provided with a pressure adjusting head. It is a pressure adjusting mechanism in the discharged particle cooling container of the apparatus.

In this pressure adjusting head, a seal pipe filled with particles forming a fluidized bed is provided in a particle discharge pipe led out of a discharged particle cooling container, and an opening degree for adjusting the opening degree of the discharge pipe at a position behind it. It can be formed with a regulating valve.

It is convenient to provide the seal pipe and the opening adjustment valve in the vicinity of directly above the discharged particle cooling container in order to enhance the sensitivity of the adjusting function.

[0016]

By providing the pressure adjusting head above the discharged particle cooling container, the pressure in the circulating fluidized bed and the pressure in the discharged particle cooling container can be equalized.
The particles in the circulating fluidized bed can be discharged smoothly.

[0017]

FIG. 1 shows an example in which the pressure adjusting mechanism of the circulating fluidized bed apparatus according to the present invention is provided in the exhaust particle cooling container (ash cooler) 7 from the combustion chamber shown in FIG.

In the figure, the high temperature bottom ash discharged through the discharge passage 71 of the dense bed 10 at the bottom of the combustion chamber 1 is caused by the flowing gas jetted from the nozzle pipe 72 inserted into the ash cooler 7. It is led out to the outside of the system from the discharge pipe 74 which is led upward and passes between the cooling pipes 73.

Reference numeral 75 denotes a seal pipe which opens at the top of the ash cooler 7, and above which, the particles forming the circulating fluidized bed are fluidized by the fluidizing gas, and the pressure at the bottom of the combustion chamber and the siphon. It is filled up to the height H where pressure is automatically adjusted by the effect.
The discharge pipe 74 is branched from below 5.

The seal pipe 75 is filled with particles in a fluidized state and flowing gas, and the particles are discharged through a discharge pipe 74 installed in the seal pipe 75, but the gas is discharged above the seal pipe 75. To be done. The gas discharged from the seal pipe 75 can be treated in the same manner as the exhaust gas of the circulating fluidized bed body by installing a connecting pipe from the upper portion of the seal pipe 75 to the exhaust gas system of the circulating fluidized bed body. Further, since fine particles are contained in the gas discharged from the seal pipe 75, it is desirable to connect to the exhaust gas system of the circulating fluidized bed body after removing dust with a cyclone or the like.

Reference numeral 76 denotes an opening adjustment valve provided near the seal pipe 75 of the discharge pipe 74. By adjusting the opening, the temperature and flow rate of the discharged particles are adjusted.

By thus filling the seal pipe 75 with particles, the pressure in the circulating fluidized bed in the combustion chamber 1 and the pressure in the ash cooler 7 are balanced, and the gas from the bottom of the combustion chamber 1 is balanced. Can be prevented.

The adjusting valve 7 provided on the discharge pipe 74
By adjusting the opening degree of 6, the flow rate is adjusted and stable operation is possible.

[0024]

The present invention has the following effects.

(1) It is possible to stably discharge particles from the fluidized bed, and it is possible to perform stable operation of the entire apparatus for a long period of time.

(2) There are very few moving parts like the conventional water-cooled screw conveyor, the operation is stable, and maintenance is easy.

[Brief description of drawings]

FIG. 1 shows an embodiment of a discharged particle cooling container according to the present invention.

FIG. 2 shows an overview of a circulating fluidized bed apparatus.

FIG. 3 shows a conventional water-cooled screw conveyor.

[Explanation of symbols]

1 Combustion Chamber 2 Hot Cyclone 3 Sealing Mechanism 4 Superheater 5 Coal Saver 6 Air Preheater 7 Powder Particle Cooling Container 71 Discharge Passage 72 Nozzle Pipe 73 Cooling Pipe 74 Discharge Pipe 75 Seal Pipe 76 Opening Adjustment Valve 8 Screw Conveyor 81 Casing 82 Conveying screw 83 Cooling water inlet for casing 84 Cooling water inlet for screw 85 Cooling water outlet 86 High temperature particle inlet 87 Cooling particle outlet 88 Seal valve 89 Intermediate hopper 9 Silo 10 Dens bed

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Tatsuhiko Egashira 46-59 Nakahara, Tobata-ku, Kitakyushu, Fukuoka Prefecture Machinery & Plant Division, Nippon Steel Corporation (72) Tetsuaki Yamamoto, Inaba, Kitakyushu, Kitakyushu, Fukuoka Nakahara 46-59 Nippon Steel Corporation Machinery & Plant Division (72) Inventor Yoshio Takei 20-1 Shintomi, Futtsu City, Chiba Prefecture Nippon Steel Co., Ltd.Technology Development Division (72) Inventor Genji Fujita Kitakyushu, Fukuoka Prefecture 59 Nittetsu Plant Design Co., Ltd., 46 Nakahara, Tobata-ku, Yokohama

Claims (2)

[Claims] 1. A pressure in an exhaust particle cooling container of a circulating fluidized bed apparatus configured as a fluidized bed heat exchanger communicating with a discharge particle discharge passage from a fluidized bed forming section, and having a pressure adjusting head in the exhaust particle cooling container. Adjustment mechanism. 2. The seal pipe according to claim 1, wherein the pressure adjusting head is filled with particles forming a fluidized bed, which is provided in a particle discharge pipe led out from the discharged particle cooling container,
A pressure adjusting mechanism in an exhaust particle cooling container of a circulating fluidized bed apparatus, which comprises an opening adjusting valve for adjusting the opening of a discharge pipe provided at a rear position.