Search

The processing of coal tar pitch (CTP) to produce clean fuel gas and carbon black (CB) is studied in a plasma reactor equipped with a direct-current plasma torch. The composition of the gas produced and energy costs were estimated theoretically for the CTP pyrolysis and gasification processes by two oxidants, namely oxygen and water vapor. We have found that the main gaseous compounds obtained in the pyrolysis and gasification processes are hydrogen (H 2 ), carbon monoxide (CO), and very often carbon dioxide (CO 2 ). For the pyrolysis case, the mean value of the synthesis gas concentration reaches a major value of 98 vol.% (H 2 - 81 vol.%, CO - 17. vol.%). However, only 23% of the initial CTP is transformed into gas phase at 1100 K and its content increases up to 37.4% at a temperature of 3000 K. For oxygen gasification, the syngas quantity is little less compared to the pyrolysis case and attains 96.6 vol.% (H 2 - 26.5 vol.%, CO - 70.1 vol.%) for T > 1100 K. An intermediate syngas content for the water steam gasification is 97.8 vol.% (with H 2 - 55.8 vol.% and CO - 42.0 vol.%). The CB produced was composed of well-defined spherical particles of 30-nm size. Furthermore, it is composed of carbon (98.2%), and followed by oxygen (1.8%) with a surface area of 97 m 2 g -1 . The thermal plasma system shows high efficiency in conversion of CTP into high-value-added products.

In the present work, a microwave excited plasma (2·45 GHz, 1 kW) was used to modify the surface characteristics of the ethylene propylene diene monomer rubber. The samples were treated with a mixture of nitrogen, hydrogen and argon plasmas. The operating gas pressure was in the 0·2-1 Torr range, the gas flowrate between 5 and 100 sccm and the treatment time varied from 10 to 600 s. The influence of the plasma treatment on the superficial characteristics of the samples was analysed by contact angle measurements and atomic force microscopy. The results show that the plasma treatment can promote an important decrease in the contact angle from 101° for untreated sample to 34° for samples treated in a mixture of H2/N2/Ar for 2 min, which corresponds an increase on the rubber surface adhesion work from 59 to 133 mJ m-2. [ABSTRACT FROM AUTHOR]

The authors regret an error in the Experimental section of the published article: [ABSTRACT FROM AUTHOR]