[nanoPost] Carbon nanofibres for nanofluids with improved heat transfer

Research Centre Russia

A new technology of carbon nanotube and nanofibre production using catalytic pyrolysis of methane (domestic gas) in laboratory-scale continuously working reactors was developed in the laboratory and patented in Russia. The process is realized in simple horizontal tubular vibroreactors and can be easily scaled-up. Now the reactor productivity is up to 15 g/h.

Typical carbon nanotubes are 2-7 nm in diameter and up to 1 μm in length; typical nanofibres are 20-40 nm in diameter and up to several microns in length. The nanofibres after simple purification (by means of diluted acid at 60o C) contain up to 2.5 wt. % of nickel nanoparticles occluded within nanofibres.

The distribution of nanotube and nanofibres diameter can be controlled via changing the catalyst used.

A know-how process of catalysts production and continuously working reactor for the process were developed.

The prime cost of nanofibres produced according to estimations will be ranged at the interval of 2 – 5 euros per 1 kg. The prime cost of the nanotubes will be higher.

Stable water and organic dispersions of carbon nanotubes or nanofibres can be produced by sonication with surfactant additions. The method is used now in the laboratory to produce macroscopic nanopaper (“buckypaper”) sheets from carbon nanofibres. These dispersions can be tested as heat transfer nanofluids.

It is possible to modify the carbon nanotubes to improve their intrinsic heat conductivity.