Super thermal insulation material is a low volume density of the material. As early as in 1992, the American scholar Hunt a J, etc on the international conference on materials engineering puts forward the concept of super thermal insulation material. After that, many scholars have used the concept of super thermal insulation material. Generally think that the use of super thermal insulation material refers to the reserve condition, its coefficient of thermal conductivity under "no convection air" coefficient of thermal conductivity of insulation materials. According to its characteristics of super thermal insulation material is generally nanopores super thermal insulation material. The most typical nanopores super thermal insulation material is the aerogel.
Nanopore super thermal insulation material shall be at the same time has the following characteristics:
1. Material in almost every pore should be below 100 nm. Pore size in the thermal insulation material is the most important factor in the thermal insulation performance; therefore, for the most part only of the insulation of pore size is less than 100 nm, in order to be entered into a category of nonmaterials.
2. Most of the material (80%), stomatal size should be < 50 nm.
According to molecular motion and the collision theory, the heat transfer mainly through the high temperature of the gas side of the high speed with low temperature side of the lower speed of molecules collide with each other, because the main component in the air nitrogen and oxygen free path are at about 70 nm, the pore silica insulation consisting of SiO2 particles in the pore size is less than the critical size, material internal eliminates the convection, cut off gas molecules heat conduction from the essence, which can be obtained than "no convection air lower coefficient of thermal conductivity.
3. Materials should have very low volume density.
4. The use of materials at room temperature and set temperature should have more than "no convection air" low coefficient of thermal conductivity. Coefficient of thermal conductivity is the main indicators of the insulation performance. At present, super thermal insulation material mainly includes vacuum insulation and 2 kinds of nanopores materials. In the stationary state of the air and the coefficient of thermal conductivity of most of the gas is very low, but due to their performance of convection, as well as to the transparency of infrared radiation, decided they cannot separate used as insulation. Therefore, it needs to adopt some solid materials to limit their convection and infrared transmitting performance. However, almost all solid materials with thermal conductivity are much bigger than still air. Therefore, in order to minimize heat conduction of solid materials, as a gas barrier of solid thin wall should be thin. At the same time, the idea to limit the amount of space between the solid nanometer order of magnitude, the conduction and convection of the gas will basically under control, such as the coefficient of thermal conductivity of insulation will be lower than the stillness of the air.
5. Material should also have good resistance to high temperature performance.
(1) Solar water heater
In the field of civil, solar water heaters and other heating device of high efficiency heat preservation can become further improving energy utilization of solar energy device.And further improve the practicality of the key factors. Nanopore super thermal insulation material was applied to water heater tank, pipes and collector than it is now. There is more than 1 times higher collection efficiency of the solar water heater, the heat loss down to levels below 30% of existing.
(2) Pool of thermoelectric applications
Can prolong the working life of the thermal battery; prevent the generated heat affected thermal battery components around.
(3) The military and aerospace field
Compared with the traditional thermal insulation materials, super thermal insulation material can use lighter quality, smaller volume equivalent heat insulation effect. This characteristic makes it plays a decisive advantage in the field of aviation and aerospace applications. If used as aircraft engine heat insulation material, has played a very good insulation effect, and reduce the weight of the engine. As outer space exploration tools and transport on the super thermal insulation material has good application prospect.
(4) To the field of industrial and building insulation
In the field of industrial and civil nanopores super thermal insulation material has extensive and potential application value. First, in the electric power, petrochemical, chemical, smelting, gold, building materials industry and other industries, thermal equipment is widespread. Industrial energy saving, the pore super thermal insulation material plays a very important also effect, some of the special location and environment, due to the weight, volume or space limit, be badly in need of efficient super thermal insulation material.
Here we make a further explaination about
ceramic fiber lining and thermal insulation material
1. Ceramic fiber lining
Petrochemical industry atmosphere furnace, vacuum furnace, ceramic fiber lining insulation is general designed to make the furnace wall temperature 80 ℃ (25 ℃ environment temperature and 0 ℃ wind speed). Atmospheric and vacuum furnace wall and furnace top heat insulation lining structure is 140 mm ceramic fiber blanket. The furnace bottom is lightweight refractory castable of 180 mm; because ceramic fiber product has good compression resilience, playing a big role in the lining seal, therefore the integrity of ceramic fiber lining sealing and heat preservation effect are good. Ceramic fiber lining makes atmospheric furnace heating furnace of vacuum furnace more efficiency in petrochemical industry.
2. Innovation, low carbon type
National policy has been made to implement energy conservation and emissions reduction, and the corresponding enterprises positively response to the call of the party and state, and particularly petrochemical industry has put forward higher requirements of heat preservation and heat insulation. Refractory material companies are constantly developing new materials, designing plan, following the steps of energy saving and low carbon.
3. the improving scheme of atmospheric and vacuum furnace and thermal insulation furnace lining
New lining structure of atmospheric and vacuum furnace: furnace lining should be changed into composite lining structure, with the total thickness of 130 mm for top and wall lining. Heat preservation and heat insulation lining structure (start from steel) need to be 30 mm ceramic fiber composite insulation board HLGX - 864 + 100 mm (50 * 2) and ceramic fiber blanket HLGX - 412. The bottom of the furnace lining is with the total thickness of 170 mm, adopting the 30 mm ceramic fiber composite insulation board HLGX - 864 + 140 mm and lightweight refractory castable HLGX - 497.
Expected effect: after adding a super thermal insulation material ceramic fiber composite insulation board as backing, in petrochemical industry, atmospheric and vacuum furnace wall temperature are normally dropped to 60 ℃ (environmental temperature 25 ℃, wind speed 0 ℃).
4. economic and technical analysis
Energy saving: the temperature of cold side wall of atmospheric decreased from 80 ℃ to 60 ℃, losing the energy of 320 w/m2. If running 300 days. It can save 83000 kilocalorie energy per year, and the equivalent of 8.3t fuel oil per year, worth 42000 Yuan.
To extend the service life: by adding super insulation energy-saving material, atmospheric and vacuum furnace lining, the service life of furnace lining can be used up to 10 years, reducing the cost of the replacement or maintenance.
