Physicochemical and rheologic study of Casigua -El Cubo coals, the State of Zulia, Venezuela

• M. Escobar Instituto Zuliano de Investigaciones Tecnológicas (INZIT)-Venezuela
• C. Alciaturi Instituto Zuliano de Investigaciones Tecnológicas (INZIT)-Venezuela
• R. Vallejo Instituto Zuliano de Investigaciones Tecnológicas (INZIT)-Venezuela
• Y. Rincón Instituto Zuliano de Investigaciones Tecnológicas (INZIT)-Venezuela
• V. González Instituto Zuliano de Investigaciones Tecnológicas (INZIT)-Venezuela
• M. Martínez Universidad Central de Venezuela
• F. Loli Independent Geological Investigation (IGI)-Estados Unidos

Palabras clave: coal, Casigua-El Cubo, rheology, proximate analysis, ultimate analysis

Resumen

Seven coals from the Carbonera Formation and six from the Los Cuervos Fm., in the Casigua - El Cubo area, the State of Zulia, Venezuela, have been characterized according to physical (HGI hardness), rheological (FSI, plastometry, dilatometry) and chemical parameters (proximate and ultimate analysis, sulfur forms, major elements in ashes). The samples from Carbonera, c1assified as sapropelic coals because of their high hardness and calorific value, together with their position in the van Krevelen diagram, possess a low rank (high percentage of volatile matter and high H/C atomic ratio) and poor rheological properties (FSI= 1.0). These characteristics make the Carbonera Fm. coals apt as a source of synthetic fuels, chemicals and as a stoker. The samples from the Los Cuervos Fm., classified as high-volatile bituminous type A coal (ASTM D 388), present properties (low moisture, ash and sulfur content average heating value of 14940 BTU/lb (m.a.f.), low fouling and slagging indexes) similar to those of Guasare, and can be used as high-quality thermal coals. Their rheological properties (Gieseler fluidity and Audibert-Arnu dilatometry) limit their application in the coke industry to that of a minority component in blends with other, strongly coking coals.