EFECTO DE LA ADICION DE AMINAS SOBRE EL RENDIMIENTO DE EXTRACCION EN CARBONES VENEZOLANOS DE DIFERENTE RANGO

Abstract

Results from the extraction with N,N,-dimethylformamide (DMF) on three Venezuelan coal (Cerro Pelado Fm., subbituminous; Paso Diablo coalmine, high volatile bituminous, and El Paraiso Fm., low -volatile bituminous), with the aim of to evaluate the effect of the addition of little amounts of aromatic amines on the extraction yield: 1) at room temperature under ultrasonic agitation , and 2) 200 ºC in a stainless steel reactor; both experiences were performed during 3 hours. All these ass ays were done also in the absence of amine, with comparative purposes. Extraction yield reach values between 4 to 12 %, with additive and at room temperetaure; while those carried out at 200 ºC show extraction variable yiel ds between 6-31 %, with the addition of little amounts of the considered amine (25 mg amine / g coal). The results evidence that lower extraction yields are provided by coals of higher rank, at lower temperature, without amine; on the other hand, the highest extraction was obtained by combining lower rank coals, higher temperature and added amine. Obtained data allowed to establish that the coal rank is the main factor in the depolymerization yield, together with the temperature. In addition, it was found t hat the effect of the amine is dependent of its structure, and this effect is the increase in the extract, in the content of heavy compounds, not solubles in acetone.