Single and double-conductor high temperature heating cable MI mineral insulated heating cable
Information source: Anhui Cable Group Views: 4032 Release time: 2014-03-13
The single- and double-conductor high-temperature MI mineral insulated heating cables produced by the Wanzhou Cable Group in accordance with national standards such as GB13033 have been widely used in petrochemical and natural gas industries such as pipeline heat tracing, tank insulation, roof and road snow melting, and building heating. After many years of practice, it is proved that the installation is convenient, safe, reliable and durable.
1. Length: ± 2%
2. Resistance value tolerance: ± 10%
3. Withstand voltage performance: Heating cable withstand voltage: 1500VAC / 1min
4. Insulation resistance: finished product test—100MΩ500VDC
5. Impermeability: After the entire cable (including the connector) is immersed in water for 12 hours, the insulation resistance must not be less than 100MΩ / 500VDC
Comparison of mineral insulated heating cables with other heat tracing technologies
Heat tracing with steam or water jacket: The biggest problem of jacket is the complicated installation process and large one-time investment. Cannot achieve automatic control. Valve parts are easily damaged in winter. The heat tracing temperature at the head and end is not uniform. Inspection and maintenance are very difficult. Heating cable and self-limiting heating cable made of plastic insulation material: short service life, maximum heating temperature can only reach + 120 ℃, large power loss, fast decay, can not guarantee the long-term stability of the initial installation power, can not meet + 150 ℃ Heating and insulation requirements for high temperature pipelines.
Comparison of the characteristics of armored mineral insulated cables and self-limiting temperature tracing cables
The main purpose of mineral insulated heating cable
1. Petrochemical industry: container heating, process pipe insulation, storage tank heat tracing, crude oil pipeline dewaxing
2. Heating and Insulation: Buildings with large-area heating factories, warehouses, agricultural horticultural greenhouses, and constant temperature control for poultry breeding and heating
3. Open-air equipment and facilities in cold areas: mechanical equipment, airstrips, TV towers, culverts, valves, gates, transportation hub facilities, schools, hospitals, outdoor stairs, intermittent liquid pumps
4. Petroleum platforms and ocean-going berths: anti-condensation on decks, cabin heating, fluid pipeline heating and insulation, and mechanical equipment insulation
5. Combustion preheating device: nuclear power plant reactor preheating, oil boiler preheater, gas device preheater
6. Aircraft runways, railway tracks, forks and other places that need heating and insulation.
MIC heating cables are divided into:
1. Copper sheathed mineral insulated heating cable can meet the requirements of high temperature conditions and heat tracing of long-distance transmission pipelines. The highest withstand temperature can reach 250 ℃; for the application requiring anti-corrosion or buried applications, high-density polyethylene HDPE outer sheath should be added, the highest withstand temperature can reach 90 ℃; and it has excellent mechanical strength.
2. Copper-nickel alloy sheathed mineral insulated heating cable The copper-nickel alloy sheathed series of mineral insulated heating cable can meet the requirements of high temperature conditions and long-distance pipeline heating. Its maximum temperature can reach 400 ℃; mineral insulated cable has excellent mechanical strength and corrosion resistance.
3. Stainless steel sheathed mineral insulated heating cable The stainless steel sheathed mineral insulated heating cable can meet the requirements of high temperature conditions and large heating power (up to 269W / m). This series of heating cables can withstand temperatures up to 650 ℃; mineral insulated cables have excellent mechanical strength and corrosion resistance.
4, 825 alloy sheathed mineral insulated heating cable
825 alloy sheath series mineral insulated heating cable can meet the requirements of high temperature conditions and large heating power (up to 269W / m). This series of heating cables can withstand temperatures up to 800 ℃; the conductor resistance values range from mineral insulated cables with excellent mechanical strength, high temperature resistance and corrosion resistance, suitable for various explosion-proof occasions and special areas.
Determination of thermal insulation parameters of mineral insulated heating cable pipes
The design theory of the mineral insulated cable heating system is mainly based on the heat that needs to be compensated to maintain a certain process temperature of the heated object, and is equipped with a mineral insulated heating cable that can generate the same heat within the allowed time to ensure that the heated object can maintain the required Process temperature can work normally.
(1) The material of the material to be heated, the flow speed in the pipeline, the starting temperature, and the working temperature to be maintained.
(2) The geometrical dimensions such as the material, thickness, diameter, and length of the pipeline or container, and the size and quantity of the corresponding valves, elbows, flanges and other accessories.
(3) The minimum temperature of the working environment.
(4) Material and thickness of insulation materials.
(5) The power capacity that the workplace can provide.
Note: For customers with special requirements, relevant parameters can be determined according to the actual needs of pipeline heating and insulation, and the factory will provide technical support.
Pipeline heating insulation, calculation method of required quantity ①, formula for calculating heat quantity required for pipeline insulation:
W = 2.72 K (T-t) / E log D / d
In the formula:
W——heat required by pipeline W / m
K—— Thermal conductivity of insulation material W / m ℃
T—— temperature to be maintained ℃
t—— ambient temperature ℃
E—— efficiency is generally 0.7
D—— Outer diameter of insulation layer mm
d—— outer diameter of pipe mm
Each attachment of the pipeline is equivalent to the length of the pipeline (meters):
② The calculation formula of heat required for pipeline heating:
W = (P × S × C × Q) × T / H × E × 3600
In the formula:
W——heat required by pipeline W / m
P——pipe weight kg / m
S——pipe specific heat J / kg ℃
C——content material weight kg / m
Q——Specific heat of content J / kg ℃
T——temperature to be increased ℃
H——Allowable heating time h
E-efficiency is generally 0.7
Laying and installation of mineral insulated heating cables (1) The technical requirements provided by Party A are used as construction technical support to determine the construction plan;
(2) The mineral insulated heating cable installed and used in the project must pass the inspection by the quality inspection department and be accompanied by a qualified certificate before it can be put into use on the site;
(3) Laying and installation workers of mineral insulated heating cables shall carry out targeted technical training and safety training. Hold a post
(4) The laying, installation and construction of mineral insulated heating cables shall be carried out in strict accordance with the design plan and construction drawings.
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