Construction Methods and Requirements of Refractory Bricks for Fluidized Furnaces

Fluidized furnace lining refractories are mainly composed of refractory bricks and monolithic refractories. The following are the construction methods of refractory bricks.

The lining masonry of a fluidized furnace is mainly divided into two parts: wall and vault.

1. Refractory brick wall masonry.

Before construction, use a theodolite to measure the center line of the furnace, re-measure the foundation elevation, and mark the height of the first layer of bricks on the furnace shell every 5 meters. Draw a layered line along the vertical direction as a reference for the furnace bottom and furnace wall masonry.

All brickwork joints must be filled with adhesive (including joints between brickwork and steel shell and between brick layers), so all brickwork joints are filled without gaps and holes. And regularly check whether the position of the masonry after masonry is accurate. For multi-layer brick masonry floors, the total thickness of the brick walls must be checked. The required thickness of mortar joints should be 2mm as far as possible (tolerance ±1mm).

A waterproof layer is set between the calcium silicate board, the high alumina insulating bricks, and the insulation refractory brick to prevent the absorption of solidified water. A plastered subfloor can be used to provide a waterproofing layer.

Expansion joints should be reserved appropriately. Paste the ceramic fiber felt on one side of the brickwork as an expansion joint to ensure the specified thickness of the expansion joint.

2. Refractory brick spherical vault masonry.

The top of the fluidized furnace is in the form of a refractory brick spherical dome. Before refractory construction, the diameter of the furnace steel shell above the supporting dust collector must be checked clockwise. When checking, divide the circle into 12 equal parts and check the circle with a rope. The length of the rope must be equal to the diameter. If defective, the housing manufacturer must be notified to have the defect repaired.

The mixing of refractory mud should be carried out in strict accordance with the provisions of the product manual.

(1) Arch foundation brick construction: According to the design requirements, the expansion joint under the tailstock ring is provided with ceramic fiber. At the position above the bracket ring and the abutment brick ring, the pressure-resistant silicon fiberboard is bonded to the steel shell. To ensure a good bond, slightly moisten the aluminum silicate fiberboard. Then, lay the supporting bricks of the arch foundation bricks on the supports. During the masonry process, check the horizontal alignment of the support ring with a level ruler, and then prefabricate the sealing ring of the furnace brick masonry according to the requirements of the drawing. However, it must be considered to set a 2mm wide sliding joint with oil paper between the ring and the support ring.

Spread mortar on the surface of the supporting brick, place the arch foundation brick on the support brick, and beat it with a rubber hammer to fix it. The bricks lean back slightly.

If the construction of the barrel masonry is not completed when the construction of the vault begins, a relatively thick auxiliary material of adhesive can be applied at the front end, so that the arch foundation bricks can be slightly inclined. Use a level to check the position of each brick. The inner edges of the bricks shall be adjusted to the corresponding inner diameter marked on the drawing. Slight unevenness can be compensated by gluing auxiliary material joints. Larger deviations from the original size can be repaired with the correct fireproof concrete or by cutting bricks to the required size. However, the brick should be at least 70% of its original thickness. After the arch foundation bricks are built, they must be fixed to prevent tilting.

(2) Top brick construction: Build irregular top brick rings according to the direction of the arch foundation bricks, and strictly follow the mix ratio of special-shaped bricks marked on the drawings for each ring. The average thickness of the mortar joints must be 2 mm, and special hardeners must be added to the bonding auxiliary materials of the masonry vault bricks. When laying bricks in both directions, the next turn of bricks should only be laid on the hardened portion of the binder after one turn has been completed. During masonry, the bonded attachments of the upper ring of bricks must be fully hardened. If checking with a tool, the tip of the tool shall not penetrate the joint of the bonded material.

Only 4 circles of bricks can be laid per day, and the unfinished irregular circles of bricks on the vault must be completed within the same working day.

(3) Crown measurement: Check the distance between 12 positions and the diameter of 4 positions outside the circle of each complete crown brick. Check the measurements against the values shown on the drawing.

Since the vault at the final dome circle is affected by gravity and may be slightly lower than the value marked on the drawing, it needs to be considered that the bricks slightly exceed the elevation position and cannot be smaller than the marked spacing or diameter.

(4) Roof closure: After the last circle of bricks is laid, the upper block of refractory concrete is poured into the center of the vault with formwork. Secure the formwork to the vault with anchor wires and pour the top stop from the top. After the concrete has hardened, the formwork is removed, and the brick masonry of the vault is built from the top.

If it is a dome with a central vent, the construction of the brickwork will continue after the last turn of bricks has been closed.