About the insulation of boiler process piping

The design scope of industrial boiler room insulation should include pipes and accessories such as steam, water, smoke, wind, coal powder and oil, as well as thermal equipment. The insulation of the boiler body shall be designed by the manufacturer. This article mainly introduces issues related to insulation of pipes and pipe fittings.

1 The purpose and requirements of insulation are different due to the purpose of insulation: 1.1 Saving fuel. In order to reduce the loss of heat during the transportation process, the heat preservation can prevent the heat lost to the outside without being kept warm. Generally, the heat loss caused by heat transfer in operation is about 12% to 22%. Therefore, heat preservation can save a lot of fuel, which has certain significance for the national economy. At the same time, pipelines and equipment can also protect pipelines and equipment from external erosion due to the addition of insulation and paint layers, increasing the service life of pipelines and equipment.

1.2 Create sanitary conditions for labor. a When the ambient air temperature is 25C, the heat pipes, accessories and equipment with a temperature higher than 50C should be insulated. The surface insulation of the insulation structure generally does not exceed 50C, and should not exceed 35 C for heavy oil pipelines; b. Protect workers from being burnt (sludge pipes, boiler drain pipes, waste steam pipes and sampling pipes, etc. In the case of possible burns to people, local insulation measures should be taken. c. In order to prevent condensation on the pipeline, when the temperature of the medium in the pipeline is greater than 0C and lower than the air temperature, it should be kept in a place with high ambient humidity.

1.3 Guarantee the requirements of the production process. For example, for hot water pipelines to prevent freezing; for heavy oil pipelines to maintain oil temperature stability, control the temperature drop of the heat medium in the pipeline and ensure that the outer surface temperature of the insulation layer is not higher than a certain value to meet special requirements.

2 The choice of insulation materials In the design of industrial boiler room, according to the designed project, according to local conditions, local materials, select a wide range of cheap, durable insulation materials.

21 selection of main insulation materials. The material of the main insulation layer should meet the following requirements: a low thermal conductivity and good thermal insulation performance; b. high heat resistance temperature, stable performance at higher temperatures; It is rich in porosity and small in bulk density, and generally should not exceed 600kg/m3. It has certain mechanical strength and can withstand certain external force. The compressive strength of thermal insulation materials is generally not less than 3kg/cm2; e. When the thermal medium temperature is greater than 120C, the thermal insulation material should be free of organic matter and combustibles; At 80~120C, it is allowed to use organic and inorganic mixed products; when the medium temperature is less than 80 C, organic products are allowed to be used, but the metal pipes should not be eroded and the surrounding air is not affected and the insects and bacteria are not easily attracted; . It has low hygroscopicity and weak water storage. Especially when the pipeline is buried in the trench or without trenches, it is not allowed to use materials with high water absorption, strong water storage and sulfide content. Easy to manufacture and easy to install.

22 According to the characteristics of the insulation body in the industrial boiler room, the recommended insulation materials used in the design are shown in the following table: the maximum use temperature of the insulation body name (C) suitable insulation material foam concrete parts (semicircular or curved) slag cotton. Glass wool tube and pipe ultra-fine glass products cement perlite parts diatomite parts, asbestos diatomite clay, cement stone parts foam concrete brick slag cotton, glass wool felt equipment and pipe 426mm or more superfine glass Products, cement perlite, diatomite parts, asbestos diatomaceous earth cement, cement stone parts, pipe fittings or equipment asbestos products (ropes, cloth, board), ultra-fine glass wool (felt or board) The choice of the protective material of the metal box 23 with asbestos and cement vermiculite as the filler. Before laying the insulation layer, the outer surface of the pipe must be cleaned and brushed with two anti-corrosive paints. In order to enhance the mechanical strength and moisture resistance of the thermal insulation structure and protect the main thermal insulation layer, an inner protective layer shall be provided at the inner surface of the main thermal insulation layer in contact with the pipe, and the outer surface of the main thermal insulation layer shall have an outer protective layer. The material used for the outer protective layer shall meet the following requirements: a. The volumetric capacity should be in the range of 800 3 . b. The compressive strength should not be less than 8kg/cm2.c. When the thermal conductivity is 50C, it does not exceed 03KPa/mh.C; d. Contains less combustibles and organic matter, should not exceed 10%; e. For the open air The protective layer of pipelines and equipment should have good waterproof performance; After drying, the surface will not cause cracks or peeling, and it is not easy to crack under temperature change and vibration; g. When the pipeline is corrosive, the protective layer should be corrosion-resistant.

Date of submission: 2005―


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