PRODUCTION AND CHARACTERIZATION OF CARBON BLACK FROM PLASMA PYROLYSIS OF NATURAL GAS

摘要

Many traditional methods for production of carbon black and hydrogen release CO_2. An alternative method that does not release CO_2 and produces carbon black and hydrogen simultaneously is the plasma torch process with natural gas as one of the input gases. In this process the natural gas is pyrolised at high temperatures, and the main reaction is CH_4 + Energy = C + 2H_2. A plasma torch of non-transferred arc with two vortex chambers was developed. Nitrogen gas, injected tangentially in the first chamber, was used as a secondary input gas to protect the cathode from erosion. In the second chamber, the natural gas was injected radially. We have carried out experiments with the following ratios between the flow rates (NL/min) of natural gas and nitrogen: 20/91, 59/102, 92/107, 129/114. We have obtained gaseous and solid products. The gaseous products, characterized by mass spectroscopy, showed the formation of hydrogen with small amounts of C_2H_2 and HCN. The produced solid phase materials, collected in several parts of the reactor, were characterized by elemental analysis, surface area measurements, XRD and electron microscopy. The materials can be classified as carbon blacks with specific BET surface area values up to 290 m~2/g. The XRD measurements showed broad lines typical of non crystalline materials. The electron microscopy results showed the presence of particles with diameter of the order of 100 nm.