Co-carbonization of Ashland A240 petroleum pitch with alkali metal carbonates and hydroxides

Abstract

Petroleum pitch was co-carbonized with the carbonates and hydroxides of Li, Na, K, Rb and Cs, using 1–15 wt% of the salt. The resultant 1173 K carbons were examined by optical microscopy to assess quantitatively the components of the optical texture. The half-peak widths of the (002) diffraction bands were determined and the porosity and surface topography of fracture surfaces of the carbons were monitored by scanning electron microscopy. The aim of the study was to assess how the anisotropic carbon of pitch coke can be replaced by isotropic carbon via addition of alkali salts with a view to the optimization of commercial gasifiers. The effectiveness of the alkali carbonates was Li < Na < K< Rb < Cs, with hydroxides being more effective than carbonates. The optical texture changed abruptly from small domains to isotropic with residual anisotropic carbon in the isotropic matrix. The half-peak widths increased with increasing isotropic carbon content.