High-temperature puffing device for producing high-thermal-conductivity natural graphite film

Abstract

The invention relates to a high-temperature puffing device for producing a high-thermal-conductivity natural graphite film. The high-temperature puffing device comprises a high-temperature puffing pipe, the outer part of the high-temperature puffing pipe is wound with a molybdenum wire for heating the high-temperature puffing pipe, the outer part of the high-temperature puffing pipe is sleeved by and supported by a ceramic outer pipe through a ceramic support ring, the outer part of the ceramic outer tube is sleeved by graphite felt, and the outer part of the graphite felt is sleeved by a metal shell; two ends of the metal shell are fixedly provided with metal-asbestos sealed end caps; one end of the high-temperature puffing pipe is provided with a feed pipe, and the other end is provided with a discharge pipe; the discharge pipe, the high-temperature puffing pipe and the feed pipe are respectively provided with a thermocouple; the outer wall of the feed tube is provided with a feed port. The device is simple and practical in structure, fast in heating speed and low in use cost, a puffing temperature field is uniform and easy to control, graphite is completely separated from heating elements, no secondary pollution can be produced, the puffing quality of graphite worms is favorably ensured, and thus a guarantee is provided for producing a high-quality and high-thermal-conductivity natural graphite film.

Description

technical field [0001] The invention relates to technical equipment for deep processing of natural flake graphite, in particular to an expandable graphite high-temperature expansion device for producing high-thermal-conductivity natural graphite film. Background technique [0002] In the graphite crystal structure, the carbon atoms in the same layer are covalently bonded to the surrounding 3 carbon atoms, the bond energy is 586kJ / mol, and the C-C bond length is 0.142nm; the distance between layers is relatively large, which is 0.335 nm. The layers are bonded by weak van der Waals force with a bond energy of 16.7 kJ / mol. Utilizing the structural characteristics of graphite, suitable substances such as concentrated sulfuric acid, nitric acid, potassium permanganate, hydrogen peroxide, etc. can be selected as intercalation agents and oxidants, and the oxidants can be used to open the edge of the graphite layer, so that the intercalation agent can be smoothly inserted into the g...

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Problems solved by technology

[0004] The above-mentioned high-temperature puffing furnace has several disadvantages: (1) When igniting natural gas or liquefied petroleum gas, since natural gas or liquefied petroleum gas is mixed with graphite intercalation compound, natural gas or liquefied petroleum gas will also follow the expansion of graphite under the action of induced draft fan. The flow of the sealed pipeline, therefore, the size of the actual expansion area and the expansion temperature are uncontrollable, which directly affects the expansion ratio and size of the worm graphite, and also increases the difficulty of subsequent paving; (2) Excessively high expansion temperature and excessive expansion The area will lead to serious burning of worm graphite and reduce the yield of worm graphite. When the expansion temperature is low, the first expansion of the graphite interlayer compound is not sufficient, and the secondary expansion phenomenon will occur, which will affect the expansion effect; (3) natural gas or liquefaction Sulfur dioxide, water vapor, etc. produced after gas combustion will adhere to the worm graphite, which will directly affect the thermal conductivity of the natural graphite film; (4) Unburned natural gas or liquefied gas or carbon dioxide produced by combustion are mixed with worm graphite , which increases the difficulty of subsequent material-gas separation and calendering of high thermal conductivity natural graphite film

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