CFB Design Description

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Summary

This product is a 55 55t/h t/h CFB boiler with sub-high pressure and sub-high temperature based on the CFB combustion technology which was developed in recent years. And this product is purified based on the CFB boiler experience which was developed by the Wuxi Huaguang Boiler Co., Ltd and the famous Chinese institutions for many years. Besides, the experience of successful operating of the same type  boiler is also for reference here. The structure of this boiler is simple, compact, and be similar to traditional pulverized coal furnace. The boiler proper is consisted by the combustion equipments, the coal feeder, the under-bed igniting equipment, the separation unit and the back feeding device, the water-cooling system, superheater, economizer, air preheater, steel frame, platform & stairs, furnace w alls.

Part 2.

Boiler parameter

Rated evaporation

75t/h

Rated steam pressure

6.3MPa

Rated steam temperature

485℃

Feed water temperature

150℃

Smoke-exhausted temperature

~ 150℃

Boiler designed efficiency

88.2%

Sewage rate

2%

Range of boiler safe and stable operating conditions

80~100%(load)

Steel consumption of boiler proper (ton)

510

Steel consumption of steel frame (ton)

145

Part 3.

Main technical data of boiler

1. Boiler external dimension (the max.): height × width wi dth × depth = 35000×13200×16600 mm. 2.

Distance between the left column and the right column: 6800mm, distance between the front and the

left column: 13100mm.

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Water volume of boiler pressure parts: when the hydrostatic test is done, it is 35 m3. When the boiler

3.

is cooking, it is 28m 3. 4.

Drum central elevation is 31850mm. Elevation of the running layer (cement concrete) is 7000mm. Elevation of the operating layer (cement concrete) is 4200mm.

Part 4.

Boiler Structure

1) The combustion device:

The fluidized air distributors adopt the water-cooling air distributor structure, and the effective area is 9.1m2. The air distributor is equipped with 299 bell wind caps, the insulating concrete and the refractory concrete could be filled on the air plates.

Air is divided into the primary air and the secondary air. PA: SA is about 55: 45. The primary air is sent from two sides of the water-cooled wind chamber, then it goes into the combustion chamber through the hood holes on the air distributors. The secondary air is distributed by two layers on height direction of the air distributor.

Two( Ф 219) slag-discharging tubes are arranged on the air distributor (besides, every slag-discharging tube is connected with one (Ф 219 ) accident slag-discharging tube), and the slag cooler can be linked here (supplied by the user).

Suggestion: During the operation process, the slag cooler can discharge slag discontinuously according to differential pressures.

Bottom of the water-cooling air chamber is equipped with two ( Ф 108) slag- discharging tubes, so that the fouling in the water-cooling air chamber could be removed regularly.

2)

Coal-feeding device:

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Three coal-feeding tubes are arranged on boiler front. Coal is sent into the combustion chamber through coal-feeding tube. Coal-sending air and coal-spreading air are arranged on coal-feeding tube to avoid clogging. The coal-sending air connects to the primary cool air; the coal-spreading air connects to the  primary hot air. Totally they take 4 percentage of total air volume. Every air-sending tube or coal-spreading air duct is arranged with one air door (designed by the design institute), so that the coal-sending air volume could be regulated. The coal inlet is linked with the combustion chamber 1500mm far away form the air caps. Suggestion: The belt coal feeder with sealed weighing device is adopted by the user, and the installation  position of the coal feeder is designed by the design institute.

3 ) Under-bed ignition device

This technology of “water-cooling air distributors, under-bed oil gun ignition” is adopted in this boiler. The oil gun would be burnt in the under-bed pre-combustion chamber. And then, by mixing with the cool air, the high-temperature smoke (