Two industrial coal blends used in cokemaking were subjected to tests in order to assess the influence of waste sawdust (SC2 from chestnut and SP1 from pine) on the quality of the coke produced. The biomass was added in quantities of up to 5 wt.%. It was observed that biomass produced a substantial decrease in the plastic properties of the industrial coal blend, with reductions in Gieseler maximum fluidity of around 50 % for 3 wt.% additions of the two different sawdusts. Carbonizations with sawdust additions ranging from 0.75 to 5 wt.% were carried out in a movable wall oven of 17 kg capacity. The bulk density of the charge was observed to decrease with increasing amounts of sawdust with negative consequences on the quality of the cokes produced. Mechanical strength was determined by means of the JIS test. Coke reactivity and post-reaction strength (CRI/CSR indices) were also assessed. The amount of sawdust added was low to prevent any deterioration in coke quality. The advantage of using biomass in coking blends should be seen as a possible way to reduce costs and CO 2 emissions and to incorporate alternative raw materials in coke production.

Three different sawdusts obtained as wastes from the furniture and flooring industry were selected to study their influence on coal thermoplastic properties. A bituminous coal with a high volatile matter content was chosen as base coal. To investigate the effect of reducing the oxygen content of the sawdusts upon the coal's properties, the sawdusts were heat treated to 250 °C. Blends of the coal with the three as-received and then heat-treated sawdusts were tested. In order to gain a better insight into the subject, the sawdusts were pyrolyzed at 400 °C to determine the effect of the resulting char and bio-oil upon the plastic properties of the base coal. The Gieseler curves corresponding to the coal-sawdust blends were calculated from the curves corresponding to the coal-char and coal-bio-oil blends. The errors obtained were in all six cases lower than the repeatability allowed by the ASTM standard for the Gieseler test. Considering that the effect of the additives is the sum of both chemical and physical effects, it was possible to evaluate the contribution of each of these to the reduction of coal fluidity. In all cases it was found that the physical effects were more important. The textural properties of the chars obtained at 400 °C from the biomass were found to be important for determining the influence of biomass on the coal fluidity.

In this work partial briquetting is employed as a means of biomass densification to allow for biomass inclusion in coking coal blends. The effect of increasing the bulk density was evaluated by comparison with direct addition. Two briquettes of different composition were studied. The influence of the briquettes on the Gieseler plasticity of the coals was determined. It was found that the effect of the binder was not enough to compensate for the decrease in plasticity produced by the inert components of the briquettes. Carbonizations were carried out in a movable wall oven of 17 kg capacity and the quality of the cokes produced was tested by evaluating their mechanical strength, coke reactivity to CO 2 and post-reaction strength. In addition, the porosity and ash chemistry of the cokes was determined and an attempt was made to establish a relation between these results and the quality of the cokes. Coke quality results suggest that 10-15 wt% of briquettes containing biomass can be included in coking blends.

Five briquettes were prepared using sawdust, a non-coking coal and a binder.Industrial coal blends were used to study the influence of the type of sawdust (pine and chestnut), the binder (coal tar and coal-tar sludge) and the size of the briquettes on the quality of the cokes produced from mixtures containing up to 15 wt.% of the five briquettes. The effect of the briquettes and briquette components on the fluidity of the industrial coal blends was investigated. It was found that biomass and non-coking coal produced a decrease in fluidity, whereas the binders increased it. The combined effect of both types of additive had the global effect of decreasing fluidity. Mixtures of the briquettes with the industrial coal blends were carbonized in a 17 kg movable wall oven in order to assess their influence on the quality of the cokes produced. Their cold mechanical strength (JIS DI150/15 index), reactivity to CO 2 (CRI index) and postreaction strength (CSR index) were also tested. The composition of the ash of the sawdusts and the reactivity of the briquette components were used as an indication of the effect on coke reactivity. The effects on cold mechanical strength and post-reaction strength were different in some cases.

Two coals, sawdust and coal tar were selected to prepare briquettes. Thermogravimetric analyses at three heating rates (i.e. 10, 20 and 30°C/min) and up to 1000°C were carried out with the briquette components. Four blends were prepared and the experimental decomposition profiles were compared with the calculated data taking into account the amount of each component in the blend. No interaction was found when comparing the experimental and calculated decomposition profiles of the blends. Isoconversional models OFW (Ozawa-Flynn-Wall) and KAS (Kissinger-Akahira-Sunose) were used to obtain the activation energies of the blend components. The activation energies obtained were introduced in the Coats-Redfern (CR) model to derive the pre-exponential factors. The thermal decomposition profiles calculated using the kinetic parameters were in good agreement with the experimental results in the case of the briquette components, but worse results were obtained in the case of the blends due to their greater complexity.

The tar derived from the pyrolysis of four briquettes especially prepared for use in cokemaking was studied. The composition of the briquettes included biomass, coal and coal tar as binder. Bio-briquettes can be considered as an alternative ecological fuel and used as a source of energy. Pyrolysis was carried out in order to produce tars.This work studies the effect of adding a sawdust waste on the characteristics of pyrolysis tars. In addition, the tars obtained from bio-briquettes and from biomass-free briquettes were compared. It was found that biomass reduces the amount of sulphur.The aromaticity of bio-tars was found to be lower than that of the tars from the biomass-free briquettes. They therefore contribute less to carcinogenicity, but they have more oxygenated groups.