Blends consisting of a high volatile bituminous coal, biomass and binder that were used in the preparation of briquettes were analyzed in order to select the best components from the viewpoint of their influence on the coal's thermoplastic properties. The raw materials were studied by means of thermogravimetry, high-temperature rheometry, hightemperature proton nuclear magnetic resonance ( 1 H NMR) and Fourier transform infrared (FTIR) spectroscopy. In addition, the fluidity of the blends was determined with the standard Gieseler plastometer test method (ASTM D 2639-74). Various parameters derived from these different techniques were used to explain the effects of biomass and binder on the fluidity of the blends with coal. It was found that the deleterious effect of biomass was mainly related to its physical properties, whereas the effect of the binder was controlled by its chemical composition. Coal tar, coal tar sludge, pine sawdust and a bio-coal derived from hydrothermally treated waste biomass obtained from pruning were the best materials for the preparation of briquettes for cokemaking.

Cokes made from briquettes composed of a high volatile bituminous coal combined with four different biomasses and four different binders were analyzed in order to evaluate the influence of these materials on their mechanical strength. The results presented in this work are part of a more extensive research plan aimed at widening the range of alternative raw materials that can be included in coking blends. The briquettes were studied by means of proximate and elemental analyses and density evaluation, whereas the cokes were subjected to micro-strength, compression strength, porous characterization and quantitative evaluation of the textural composition by means of polarized light microscopy (PLM). Various parameters derived from these different techniques were used to explain the effects of biomass and binder on the strength of the coke prepared with the briquettes. Bituminous binders are the most effective because they increase Gieseler fluidity and have a lower volatile matter content than molasses and paraffin. The biomasses that gave rise to the most resistant bio-cokes were lignin and a bio-coal, derived from hydrothermally treated waste lignocellulosic biomass.

Five blends prepared with torrified sawdust, coal plus either coal tar, coal tar sludge, paraffin or molasses designed to serve as binder in the preparation of briquettes were pyrolysed in a rotary oven. The coal and the torrified sawdust used in the preparation of the blends were also studied. The condensable gases were analyzed by gas chromatography (GC) and infrared spectroscopy (FTIR). The permanent gases were also analyzed by gas chromatography. The concentration of nineteen polyaromatic hydrocarbons in the condensable products was analyzed with special focus on those considered as priority and carcinogenic pollutants. The results obtained from FTIR were confirmed by those obtained by GC. It was found that the inclusion of biomass produces a decrease in the amount of (polyaromatic hydrocarbons) PAHs in the condensable pyrolysis products and an increase in the concentration of CO2 in the gases, although these gases are carbon neutral.

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Two high-rank bituminous coals and three sawdusts of different origin were selected to study the effect of biomass on coking pressure. The effect of the biomass on the thermoplastic properties of the coals was assessed by means of the Gieseler test. In addition, the effect of the biomass on the thermal decomposition of the coals was studied by means of thermogravimetric analysis together with the modification of the permeability of the coal plastic phase. The individual coals and the blends were carbonized in a 17 kg movable wall oven; the coking pressure developed was measured and the quality of the resulting coke was assessed. It was found that the sawdust reduced coking pressure, especially in the case of the coal that developed the highest coking pressure. This effect was attributed to the modification of the permeability of the plastic phase to gas flow. It was concluded that although the addition of sawdust produces a decrease in coking pressure, additions should be limited to small amounts to avoid excessive deterioration of the quality of the product.