Identification of polymers in waste tyre reinforcing fibre by thermal analysis and pyrolysis

The composition of the reinforcing fibre obtained from the recycling of scrap tyres was analyzed with a view to finding the most suitable applications for it. The material (RF) was separated into two different parts i.e. fibre (F) and microfibre (MF) to ensure the maximum homogeneity of the material under study. Thermogravimetric analysis (TG) together with differential scanning calorimetry (DSC) and infrared spectroscopy (FTIR) were used to identify the polymers present in the waste and to determine in what proportions they were present. Determination of the temperatures of maximum volatile matter evolution (Tmax), the yield at the end of the pyrolysis and the melting temperatures yielded very useful results for the identification of the polymers. In order to confirm the results obtained, pyrolysis of the pure polymers was carried out and the decomposition products were analyzed. The results were then compared with the oil composition data derived from the pyrolysis of the waste fibres. Our results showed the presence of two polyamides, rayon, polyester and aramid.The research leading to these results has received funding from theSpanish MICINN Project reference CTM2009-10227. BA thanks the Government of the Principado de Asturias for the award of a predoctoral grant with funds from PCTI-AsturiasPeer reviewe

Influence of biomass on metallurgical coke quality

Two industrial coal blends used in coke making 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 CO2 emissions and to incorporate alternative raw materials in coke production.The authors are grateful to the Research Fund for Coal and Steel (RFCS) for financial support (Project RFCR-CT-2010-00007). M.G.M. thanks the Government of the Principado de Asturias for the award of a predoctoral grant with funds from the PCTI-Asturias within the Severo Ochoa program. Comments by anonymous reviewers on a previous version of this paper are acknowledged.Peer reviewe

The influence of the pyrolysis conditions in a rotary oven on the characteristics of the products

The pyrolysis of 1:1 blends of reinforcing fibre (RF) from tyre wastes with low rank bituminous coal was carried out in a rotary oven. The pyrolysis conditions were modified in order to study their influence on the yield and characteristics of the char and oil obtained. The variables studied were as follows: rotation speed, final pyrolysis temperature, N2 flow and heating rate. The textural characteristics of the char were studied by means of N2 adsorption at 77 K, whereas the oil composition was studied by infrared spectroscopy and gas chromatography. Modification of the variables did not have any effect on the composition or textural properties of RF/coal char. However, an increase in the nitrogen flow, rotary speed and a decrease in the heating rate led to a higher oil yield with more oxygenated groups and less aromaticity. These conditions also caused an increase in the contribution of the light oil to the oil yield. Moreover, an increment in the final temperature also resulted in a higher percentage of light oil, a greater amount of aromatic compounds and smaller number of oxygenated groups.The research leading to these results has received funding from the Spanish MICINNCTM2009-10227. BA thanks the Government of the Principado the Asturias for the award of a predoctoral grant with funds from the PCTI Asturias (BP11-046).Peer reviewe

Fuel-oils from co-pyrolysis of scrap tyres with coal and a bituminous waste. Influence of oven configuration

Two wastes from the tyre recycling industry – the fibers used as reinforcing material and tyre crumbs – were pyrolyzed in two ovens of different configuration. Blends with a low rank coal and a bituminous waste were also prepared to modify the composition of the oils obtained from the pyrolysis of the tyre wastes. Elemental analysis, calorific value, Fourier transform infrared spectroscopy (FTIR) and gas chromatography were used to determine the oil composition. A comparative study taking into account the configurations of the ovens and the raw materials was carried out. The oils produced in the rotary oven were found to be more aromatic and to have lower oxygen contents. Depending on the type of oven and the material used in the co-pyrolysis process it is possible to obtain a fuel-oil with a specific heating value and sulfur content. It is also possible to obtain oil with more than 20% limonene and 20% BTX (benzene, toluene, xylene). The amount of aliphatics can be increased by including a coal in the pyrolysis process and the amount of aromatics can be increased by co-pyrolysis with a bituminous waste.The research leading to these results has received funding from the Spanish MICINN project reference CTM2009-10227. BA. thanks the Government of the Principado de Asturias for the award of a predoctoral grant with funding from PCTI-Asturias.Peer reviewe

Determinacion del punto final de la coquizacion mediante analisis en linea Aplicacion a la coquizacion humeda y precalentada

Available from Centro de Informacion y Documentacion Cientifica CINDOC. Joaquin Costa, 22. 28002 Madrid. SPAIN / CINDOC - Centro de Informaciòn y Documentaciòn CientìficaSIGLEESSpai

Pyrolysis of blends of coal and tyre wastes in a fixed bed reactor and a rotary oven

The pyrolysis of blends of two wastes from scrap tyres with a coal of 36 wt.% db volatile matter content was carried out in two ovens of different configuration in order to compare the characteristics of the products obtained. The rotary oven was expected to improve the blending of the raw materials and to promote a synergistic effect. Mass balances were performed with gas and oil yields showing the greatest differences. The chars obtained were studied on the basis of their true and apparent densities, Hg porosimetry and by determining their surface area under N2 at 77 K and under CO2 at 273 K. The chars were also examined by scanning electron microscopy (SEM). The oils were subjected to Fourier spectroscopy (FTIR). It was observed that the oils obtained in the rotary oven were more aromatic and contained smaller amounts of oxygenated functional groups due to their higher residence time in the hot zone of the reactor.The research leading to these results has received funding from the Spanish MICINN project reference CTM2009-10227. BA thanks the Government of the Principado de Asturias for the award of a predoctoral grant with funds from PCTI-Asturias.Peer reviewe

Effect of the addition of waste sawdust on thermoplastic properties of a coal

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.The authors are grateful to the Research Fund for Coal and Steel (RFCS) for financial support (Project RFCR-CT-2010-00007). M.G.M. thanks the Government of the Principado de Asturias for the award of a predoctoral grant with funds from the PCTI-Asturias within the Severo Ochoa programPeer reviewe

Recycling tyre wastes as additives in industrial coal blends for cokemaking

Two industrial coal blends (B1 and B2) used in cokemaking were selected for this study. Two wastes from scrap tyres (TC, F) were added to these coal blends at different ratios (98:2 and 95:5). The investigation was focused on assessing the influence of the additives on thermoplastic properties of coal by means of the Gieseler fluidity test and thermogravimetric analysis. In addition, the blends were carbonized in a 17 kg electrically heated movable wall oven in order to examine the quality of the resultant cokes. Quality of the cokes produced was evaluated by measuring their cold mechanical strength, reactivity and post-reaction strength. It was found that ash composition of the additives contribute to a deterioration in coke quality. Moreover, F causes a greater decrease in coke strength after reaction with CO2 due to the diminution of bulk density in the coking process and to the higher basicity index. Trace elements were also studied in relation to waste addition.The research leading to these results has received funding from the European Union's Research Fund for Coal and Steel (RFCS) research programme under grant agreement No. RFCR-CT-2010-00007 and contract No. RFCR-CT-2006-00002.Peer reviewe

Partial briquetting vs direct addition of biomass in coking blends

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 CO2 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.The research leading to these results has received funding from the European Union's Research Programme of the Research Fund for Coal and Steel (RFCS) research programme under grant agreement No. [RFCR-CT-2010-00007]. M.G.M. thanks the Government of the Principado de Asturias for the award of a pre-doctoral grant with funds from the PCTIAsturias within the Severo Ochoa program.Peer reviewe

Effect of Adding Low-Density Polyethylene to Coal on Semicoke Structure and Morphology

The objectives of this study are to determine the influence of low-density polyethylene (LDPE) on the structure and morphology of the resulting semicoke as an intermediate carbon material in metallurgical coke manufacture; and, to explain the differences in the fluidity and the coking pressure generated during the carbonization process.The Spanish Ministry of Education and Science (Ministerio de Educación y Ciencia), Project CTM2004-03254. El Principado de Asturias, "Plan de Investigación, Desarrollo Tecnológico e Innovación de Asturias”.Peer reviewe