JPH025230Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a fireproof and insulating structure for a duct in a boiler plant.

In gas turbine waste heat boiler plants,
As shown in Figure 1, in recent years, the waste gas1 (approximately 600
℃) is led through duct 2 and used as a heat source for boiler 3 in many cases. In FIG. 1, 4 is a refractory heat insulating material, 5 is an auxiliary combustion burner, 6 is a gas turbine, and 7 is a stack.

A refractory insulation material 4 is installed on the inner surface of the duct 2 to minimize heat loss, but the refractory insulation material 4 is subject to sudden rises and drops in waste gas temperature due to startup and shutdown of the gas turbine 6, that is, thermal shocks. .

It is known that conventionally commonly used refractory bricks, cabstals (unshaped refractories), etc. are relatively weak against the above-mentioned thermal shock, and the life of the duct 2 is significantly shortened due to cracks developing and falling off. There is. Therefore, in recent years, ceramic fibers have rapidly become popular in bulk, blanket, felt, and board forms. This ceramic fiber has many advantages such as (a) high heat resistance, (b) low thermal shock resistance, (c) low thermal conductivity, (d) low specific heat, (e) light weight, and (f) low crack occurrence. On the other hand, it also has disadvantages such as (a) heat shrinkage rate of 1 to 5%, (b) poor wind resistance, and (c) high air permeability.

Therefore, attention is being paid to a method of increasing wind speed resistance by making the fiber direction perpendicular to the duct wall as shown in Figure 2. In the figure, 8 is the outer wall of the duct, 9 is the fiber direction, 10 is the block, 11 is the module, and t
indicates the thickness, and the arrow on the upper left indicates the direction of waste gas flow.
Furthermore, a heat-resistant coating may be applied to prevent the thermal layer from entering the heat insulating layer and the fibers from peeling off due to wind speed. This method is characterized in that costs can be reduced by forming the block into a block of approximately 300 x 300 mm (thickness is arbitrary) and attaching it to the duct outer wall 8. However, the wind speed is 10m/
The actual capacity is only about 20 m/s, which is insufficient to meet the required value of 20 to 30 m/s for the gas turbine waste heat boiler and the like.

The present invention was developed in an attempt to eliminate these drawbacks of the conventional example, and aims to enhance the wind speed performance while taking advantage of the advantages of the ceramic fiber block.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In FIGS. 3 and 4, reference numeral 11 is a heat insulating block, 12 is an anchor bolt, 13 is a nut, and 14 is a heat insulating block.
is the outer wall of the duct, 15 is glass cloth or ceramic fiber cloth, 17 is anchor bolt, 18 is adjustment spring, 19 is ceramic fiber rope or glass rope, 20 is knot, 21 is coating material, 22 is fiber presser, W is Showing a dish towel.

A heat insulating block 11 whose surface is coated with a coating material 21 is installed on the duct outer wall 14 with anchor bolts 12 and nuts 13. The anchor bolt 12 and the duct outer wall 14 are fixed by welding or screws, and the block 11 is covered with a glass cloth 15.

The ends of the glass cloth 15 are overlapped with adjacent cloths and sewn together with glass ropes as necessary.

On the other hand, the glass rope 19 that fixes the glass cloth 15 is an anchor bolt 1 fixed by welding or screws.
7 in advance, take out the end, tie a knot 20 at the overlapped part of the glass cloth, and fix it. An adjustment spring 18 is installed on the anchor bolt 17.

Next, the action and effects will be described.

The glass cloth 15 must be stretched in the plane direction to prevent flapping (impulse) caused by gas wind speed and to absorb thermal contraction. For this purpose, the spring 18 attached to the bolt 17 pulls it toward the duct outer wall 14 and fixes it. On the other hand, when the coating material 21 comes into direct contact with the gas, cracks occur, and depending on the wind speed, the fibers are scattered along with the coating material 21. Coating material 2 is applied by covering the fiber block with coating material with glass cloth 15.
1. Prevents peeling and scattering. The required thickness of the glass cloth 15 is determined by the wind speed and its direction. In addition, the glass cloth 15 used includes:
Requirements include (a) heat resistance, (b) low heat shrinkage, (c) high tensile strength, (d) high wind speed resistance, and (e) low wind resistance. Considering the cost, glassy silica fibers are desirable as an example.

According to the present invention, the wind speed resistance, which is a disadvantage of ceramic fibers, can be strengthened, and the insulation thickness can be kept constant, thereby preventing a decline in insulation performance and extending the life of the fireproof insulation material.

Glass cloth also shrinks by 1 to 5% due to heat, but the tension generated in the glass cloth can be adjusted by means of springs attached to bolts.

The spring is installed as close to the outer wall of the duct as possible, and the glass cloth is fixed with a glass rope that has low thermal conductivity, so it does not create a thermal bridge and does not cause heat loss.

On the other hand, since the bolts and springs do not reach high temperatures, inexpensive general steel materials can be used, which is effective in reducing costs.

[Brief explanation of the drawing]

Fig. 1 is a system diagram of a gas turbine waste heat boiler plant, Fig. 2 is a schematic perspective view showing a method of strengthening wind speed resistance, Fig. 3 is a sectional view showing the configuration of the present invention,
FIG. 4 is a schematic diagram showing a glass cloth overlapping portion. 11...Insulation block, 12...Anchor bolt, 13...Nut, 14...Duct outer wall, 15
... Ceramic fiber cloth or glass cloth, 17 ... Anchor bolt, 18 ... Adjustment spring, 19 ... Ceramic fiber rope or glass rope, 20 ... Knot, 21 ... Coating material, 22 ... Fiber presser fitting.

Claims (1)

[Scope of utility model registration request] The surface of the ceramic fiber block with a coating material is covered with ceramic fiber cloth or glass cloth, and a tension adjustment spring is installed on the inner surface of the duct in contact with the outer wall of the duct in order to avoid thermal contraction of the ceramic fiber cloth or glass cloth or impulses due to gas flow velocity. In addition, by fixing the ceramic fiber cloth or glass cloth with a ceramic fiber rope or glass rope, and fixing the cloth with the rope, the insulation performance is not reduced and the material of the adjustment spring is kept to a low quality. Fireproof insulation structure of the duct.