Catalytic Chemical Vapour Deposition (CCVD) is considered as the most suitable technique for the large scale and low-cost production of multiwalled carbon nanotubes. We have studied the effect of the preparation process, and of the support particle size on the catalyst efficiency, conversion yield of the carbon source and diameter of the nanotubes produced. When 50 nm calcite CaCO3 particles support the Fe2Co nanoparticles and when the catalyst is freeze dried to avoid the particles agglomeration, 85% of acetylene is converted into MWCNTs; and by using our rotary tube furnace, 1200 g of MWCNTs can be produced per day.