Anti - Corrosive RTV Silicone Coatings For Coal Power Plant Chimneys Protection

1, Overview of the product

Our company, cooperating with famous colleges and universities in China, developed masonry glue specific for the stack anti-corrosive construction after thorough and detailed tracking and understanding of the stack desulfurization anti-corrosive projects. The product is divided into A component and B component. It mainly uses organic silicon as the main material and has excellent properties of weather resistance, high temperature resistance, acid resistance and fire resistance, which completely meet the technical requirements for the stack anti-corrosion of fire plants and are used widely.

Through years of operation and due to the severe operating environment in the stack and factors occurred during the construction process, acid liquid on the inner wall of the stack will infiltrate and corrode the outer wall of the stack along the cracks, which will cause serious danger to the safe operation of the stack. To solve the problem, we also developed a special anti-corrosive rubber and an anti-corrosive bottom coating for the stack. The product is single component and uses modified organic silicon as the main material. It is treated in a special way and added with fillers of excellent acid resistance. Advanced manufacturing technology is adopted to process the product. The bottom coating should be sprayed to the concrete stack inner wall by professional spraying equipment and cure in room temperature. The stack anti-corrosion rubber can be applied directly to the stack wall surface and floated. The cured rubber coating has extremely excellent properties of weather resistance, acid resistance, and leakproofness, which prevents the stack inner wall completely from the glue gas and enhances the service life of the stacks.

2, Construction performance

a.  Stack anti-corrosion masonry glue: Good thixotropy, easy to apply; the glue does not run during facade construction; in the process of testing, mixing uniformity of the A, B components can be observed through color change, thus it’s easy to handle the construction. It’s easy to feed B component and simple to operate at site. The ratio of A, B components can be changed conveniently according to different conditions of the seasons and construction sites. Construction time after the glue is mixed should be controlled to meet the requirements of construction and curing time.

b.  Stack anti-corrosion rubber: moderate viscosity, difficult to flow, easy to apply and convenient to use. The rubber cures into elastomer at room temperature by absorbing only a little moisture in the air, needing no additive conditions.

c.  Primer paint: Low viscosity, easy to spray, excellent adhesion, convenient to apply and curing fast at room temperature.

3, Product performance characteristics

a,  Extremely strong resistance to acid

Organic silicon possesses acid resistance and the ability of dilute alkali solution. Usually, adding fillers with excellent acid resistance property and silane coupling agent to the organic silicone rubber can improve the acid resistance of it to some extent. Our company adopted special treatment of the fillers to bond the organic silicon and the fillers together tightly so that the acid resistance of the stack rubber is increased furtherly.

b, Remarkable heat resistance

During the flue gas emission of stacks in power plants, the temperature of the flue gas changes between 40℃ and 150℃ as working conditions change. The temperature will exceed 180℃ or even higher under accident circumstances. Thus the stack anti-corrosion rubber is required to be excellent in heat resistance. The organic silicone rubber has a good thermal oxidation stability because the backbone of it consists of silicon-oxygen bond. The mechanical properties of it do not change much at below 150℃ and it can be used for more than 1000h at above 200℃. The stack rubber of our company is better in heat resistance due to the addition of heat-resistant additive. It can meet the requirement of working temperature in the stack as anti-corrosive material.

c, Excellent weather resistance

The backbone of the organic silicon does not contain unsaturated bond and the silicon-oxygen bond is stable to oxygen, ozone and UV rays. As a result, the organic rubber does not crack, degrade or grow tacky after long-term exposure to UV rays or wind or rain through outdoor solarization and accelerated aging test.

4, Performance indexes of KDW--982 foam brick adhesive (masonry glue)

5, Application method

a,  Glue distribution

     Proportion recommended is A component : B component=10:1. The operating time is 1 hour when the working temperature is 25℃. B component dosage can be increased or decreased in a range of 15% to speed up or slow down the curing speed.

b, Stirring

Use electrical tools or other blenders to stir the glue. The glue is supposed to be black after mixing uniformly. If there is white or lightly-colored glue or partly too deep, that means it needs to be stirred furtherly until it is uniformly colored.

c, Pasting

Coat the stack anti-corrosive glue on the foam glass brick/lightweight vitrified brick, and make sure the thickness of the glue layer is no less than 3mm on the paste face between the brick and the stack inner wall, and the glue layer thickness is no less than 1mm on the contact face between brick and brick.

Notes:

(1). The product can only be applied when the A and B components are mixed up uniformly according to appropriate proportion. If the mixture is not uniform or the proportion is not in the recommended range, then construction quality will not be guaranteed.

(2). The curing speed is largely affected by construction temperature. The higher the temperature is, the faster the curing speed.

6, Packaging and storage

(1), Packaging specifications:

A component: Barrels, 25kg/ barrel

B components: Flexible packaging, 0.4kg/ branch; plastic tube packaging, 0.33kg/ branch

(2) Storage and validity period

Both A and B components should be stored in sealed containers and the storage temperature should be of or below 28℃. The validity period is 9 months at the temperature between 23℃ and 25℃ under sealed state.