NOVELTY - Carbon nanotube powder comprises carbon nanotubes, which: consist of one or more graphite layers that are made of two or more graphene layers, which are arranged one above the other; and form a rolled structure, where the carbon nanotubes exhibit a spiral shaped graphite layers arranged in cross-sections, where the average diameter of the carbon nanotubes is 3-100 nm, preferably 5-30 nm.    USE - The carbon nanotubes are useful: as additives for polymers, rubbers, ceramics, metals, alloys, glasses, textiles and composite materials; as conductive additives in electrodes, solar cells, actuators, sensors, inks or pastes and in energy storage, preferably in batteries, accumulators, fuel cells or condensators; as substrate for pharmaceutical active materials or for plant protective active materials; as absorber preferably for volatile compounds, e.g. for gases or for biological compounds e.g. for enzymes; and as substrate for catalyst (all claimed).    ADVANTAGE - The carbon nanotubes show the characteristics of the well known multi-walled carbon nanotubes. The carbon nanotube material exhibits a high purity in relation to the metallic impurities and amorphous carbon.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for:    (1) carbon nanotubes having the same characteristics as mentioned above; and    (2) production of the carbon nanotube powder, comprising catalytically disintegrating hydrocarbon having 1-3 carbon atoms, with a heterogeneous catalyst at 500-1000 degrees C, preferably 600-800 degrees C in a reactor comprising a moving bed, where: the catalyst is a transition metal catalyst based on cobalt and manganese with a cobalt portion of 40-60 mol.% and a manganese portion of 40-60 mol.% relative to the sum of cobalt and manganese; the average retention time of the catalyst in the reaction zone is maximum one hour; and the hydrocarbon is reacted individually or as mixture, together with inert gas, preferably nitrogen or inert gas.    DESCRIPTION OF DRAWING(S) - The figure shows a cross-sectional view of a multi-walled cylindrical carbon tubes.