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El incremento anual de la producción mundial de plásticos conlleva una generación ingente de residuos. Debido a ello, surge la necesidad de encontrar soluciones sostenibles enmarcadas en modelos de economía circular, donde el reciclaje químico resulta crucial para llevar a cabo dicha transición. En este sentido, la pirólisis, un proceso de degradación térmica en atmósfera libre de oxígeno, permite recuperar diferentes compuestos precursores de combustibles o materias primas. Particularmente, este proceso permite obtener altos rendimientos del monómero original para el caso del poliestireno (PS), aunque todavía es necesario realizar una caracterización más profunda de los productos y optimizar el proceso tanto de pirólisis como de repolimerización para conseguir un polímero de una calidad comparable al original. Este estudio tiene por objeto la obtención de una fracción líquida rica en estireno (pyro-oil) con potencial para ser utilizada como materia prima en la producción de nuevos polímeros.

El objetivo de la UE es reducir drásticamente la huella de carbono hasta un 80-95% en los sectores industrial y residencial en 2050. La pirólisis es un proceso ligeramente endotérmico que permite la conversión de distintos tipos de biomasa en productos de alto valor añadido como el bio-aceite, que puede ser considerado un vector energético de carácter renovable y el bio-char, cuyo uso como fertilizante renovable está captando un alto interés. Industrialmente, la estrategia más utilizada para hacer frente a los altos coeficientes de transferencia de calor (150-350 W/m2K) es el uso de transportadores de calor, principalmente arena, cuyo calentamiento se realiza a partir de la combustión del gas y/o el bio-char obtenido en el propio proceso de pirólisis. Sin embargo, para ser competitivo tanto tecnológicamente como económicamente con los procesos actuales basados en recursos fósiles, el desarrollo de nuevos procesos de alta eficiencia que permitan el aprovechamiento de todos los productos, especialmente el bio-char como sumidero de carbono, va a ser clave.

El negro de carbono (CB, por sus siglas en inglés Carbon Black) es uno de los materiales sólidos más utilizados en la industria. La producción de negro de carbono está enfocada principalmente a su uso como material de refuerzo en productos de caucho, como neumáticos, mangueras o correas de transmisión, así como en su aplicación como el pigmento negro más común[1]. La producción tradicional de CB es un proceso energéticamente intenso que produce una huella de carbono aproximada de 2,4 kgCO2/kgCB. Por tanto, el desarrollo de una tecnología industrialmente viable para el reciclado del CB es un reto importante para la industria. Para el caso concreto de los materiales de construcción, como puede ser el EPDM (Ethylene Propylene Diene Monomer), el uso de negro de carbono mejora las propiedades mecánicas del producto, además de reducir el coste del producto final. Los cauchos de EPDM son materiales ampliamente utilizados en la industria, con una producción anual de más de 1,5 millones de toneladas. Su uso se debe fundamentalmente a su excelente resistencia a los elementos ambientales como la radiación UV, el agua y el calor. Sin embargo, la resistencia física de estos materiales dificulta el adecuado tratamiento de los residuos generados al final de su la vida útil. Generalmente, la eliminación de estos residuos se realiza mediante valorización energética, incineración o incluso deposición en vertederos, a pesar del alto impacto medioambiental negativo que supone. Uno de los procesos de reciclado químico más interesantes desde el punto de vista ambiental del caucho para la recuperación del CB de los cauchos es la pirólisis. Este proceso térmoquímico en ausencia de oxígeno permite separar la fracción volátil del material de la fracción no volátil, denominada RRCB [2] (Raw Recovered Carbon Black, por sus siglas en inglés), que contiene el negro de carbono y las partes inorgánicas utilizadas en la síntesis del producto. Sin embargo, el uso del sólido producido en el proceso d

This work describes the key features involved in the design and operation of a pilot scale distillation column for the recovery of value-added products from tire pyrolysis oil (TPO), as part of the BLACKCYCLE project. The distillation unit was designed using engineering heuristic rules, simulated distillation (SimDist) data and Aspen Hysys ® modeling. The distillation plant consists of a packed column with a nominal throughput of 20 kg/h, and is classified at the fifth technology readiness level (TRL-5). The commissioning and results of long-term experimental campaigns for validation purposes are also presented. In this way, important information is gathered for the design of larger plants. The distillation unit was tested and validated using TPO produced from a pilot scale continuous single-auger pyrolysis plant. A first distillation was performed yielding a heavy fraction (HF-1) with properties suitable for carbon black production, while the light fraction (LF-1) includes the presence of value-added chemicals such as benzene, toluene, ethylbenzene and xylenes (BTEX) and limonene. The LF-1 was also used for a second distillation, producing a stream high in limonene at the bottom (HF-2), and another one high in BTEX compounds at the top (LF-2), which are valuable raw materials for polymer production and petrochemicals, respectively. The key results obtained here are expected to provide an outstanding impetus for the circular economy of complex streams such as end-of-life tires (ELTs) by combining pyrolysis and distillation technologies.

Tire pyrolysis oil (TPO) is one of the most interesting products derived from the pyrolysis of end-of-life tires. Among others, it contains valuable chemicals, such as benzene, toluene, ethylbenzene, and xylene (BTEX), as well as limonene. In order to recover these chemicals, a pilot-scale distillation plant has been designed, erected, and operated using TPO derived from an industrial-scale pyrolysis plant. The distillation facility consists of a packed column (20 kg/h) and is within the fifth technological readiness level. This work describes for the first time the fractioning of the TPO in a continuous operational mode under industrially relevant conditions. For this purpose, different reboiler temperatures (250–290 °C) and reflux ratios (up to 2.4) were preliminarily assessed on the yields and properties of the resulting products: light fraction (LF) and heavy fraction (HF). Thus, the distillation plant is capable of producing 27.0–36.7 and 63.3–73.0 wt % of LF and HF, respectively. The highest BTEX concentration in the LF (55.2 wt %) was found using a reboiler temperature of 250 °C and a reflux ratio of 2.4. Contrarily, the highest limonene concentration (4.9 wt %) in the LF was obtained at 290 °C in the reboiler without reflux. In this sense, the lower the reboiler temperature, the higher the BTEX, and the lower the limonene concentration in the LF. The main results herein obtained serve to gain key insights to operate packed distillation columns using complex and promising hydrocarbons as TPO in order to recover valuable products. In addition, this work provides significant information for optimizing the recovery efficiencies of both BTEX and limonene, as well as their potential applications including that for the resulting HF.

Figure S1: Calibration mix chromatogram obtained for ASTM D2887 method. Figure S2: Calibration curve obtained for ASTM D2887 method. Figure S3: Chromatograms obtained for the a) TPO, the first distillation of TPO b) light fraction (LF), c) heavy fraction (HF) and the second distillation of the light fraction of TPO d) LF and e) HF. Table S1: Percentage of relative area obtained with the quantification ion (m/z) for the TPO by GC-MS according to the NIST2020 library (BTEX=benzene, toluene, ethylbenzene, xylenes; CC= cyclic compounds, AAA= alkanes, alkenes, alkynes, SB= Substituted benzenes, no BTEX, HC= heterocyclic compounds, I= indenes, PAH= polycyclic aromatic hydrocarbons, O= others). Table S2: Percentage of relative area obtained with the quantification ion (m/z) for the first distillation of the TPO, LF-1, by GC-MS according to the NIST2020 library. Table S3: Percentage of relative area obtained with the quantification ion (m/z) for the first distillation of the TPO, HF-1, by GC-MS according to the NIST2020 library. Table S4: Percentage of relative area obtained with the quantification ion (m/z) for the second distillation of the TPO, LF-2, by GC-MS according to the NIST2020 library. Table S5: Percentage of relative area obtained with the quantification ion (m/z) for the second distillation of the TPO, HF-2, by GC-MS according to the NIST2020 library.

Table S1. TPG Composition. All data in volume percentage. Table S2. CTT Sulphur mass balance. All data in weight percentage. Table S3. PCT Sulphur mass balance. All data in weight percentage.

Pyrolysis is a chemical recycling process of interest as a means to achieve a sustainable circular economy for end-of-life tyres (ELTs). In the pyrolysis process, ELTs are converted into tyre pyrolysis gas (TPG), tyre pyrolysis oil (TPO) and raw recovered carbon black (RRCB). This work investigates for the first time the effect of different temperature profiles by using a single-auger pyrolysis reactor in an industrially relevant scale (TRL-5). Since the development of this process at this representative scale is quite limited and the temperature profile has not been previously studied, the results achieved in this work can provide a useful database for the development of this process at industrial scale. For this purpose, two different sources of ELTs, commercial truck tyres (CTTs) and passenger car tyres (PCTs), were used. Accordingly, the experimental campaign was conducted using two different incremental temperature profiles (425-550-775 °C and 600-700-800 °C) based on those that can be replicated in an industrial-scale auger pyrolysis plant. For the sake of comparison, two isothermal heating conditions (500-500-500 °C and 600-600-600 °C) were also tested. The results confirmed the remarkable influence of temperature profile on both the distribution and properties of products. The 425-550-775 °C temperature profile was found to enhance limonene production, which is associated with the minimisation of secondary reactions in the first heating zone of the reactor. Additionally, there were very low carbonaceous deposits found in the RRCB because of the high severity of devolatilisation conditions in the third heating zone of the reactor. On the other hand, when the temperature profile was raised, the production of single-ring aromatics, particularly benzene, toluene, ethylbenzene and xylenes (BTEX) significantly increased in the TPO at the expense of limonene. Thus, from this strategy, it is possible to tune the properties of the products depending on the requiremen

Las membranas basadas en óxido de grafeno (GO) pueden mejorar sus propiedades en procesos de filtración de aguas mediante su modficación química y estructural. La reducción de las membranas de GO provoca la eliminación de los grupos de oxígeno, lo que conduce a un menor espacio entre láminas de GO, aumentando el rechazo de sales y compuestos orgánicos, pero también afecta la hidrofobicidad y modifica el transporte de agua. Existen diversas metodologías para la reducción del GO, la reducción asistida por radiación UV de membranas es una alternativa cuyos resultados han sido probados en la separación de tintes. Este trabajo profundiza en la modificación de membranas de GO mediante radiación UV.

El negro de carbón o negro de carbono (CB por sus siglas en inglés, Carbon Black) es un material carbonoso amorfo producido por la combustión incompleta de hidrocarburos derivados del petróleo. Por sus características como reforzante, la producción de este material se destina mayoritariamente a la fabricación de neumáticos, por lo que resulta razonable enfocar la atención a la recuperación del mismo una vez los neumáticos han terminado su vida útil. Adicionalmente, la producción de CB supone un serio impacto ambiental en forma de emisiones de CO2 de origen fósil (del orden de 2.4 kg de CO2 por kg de CB producido). El coste de producción de CB mediante el proceso más común (Furnace Black) es bastante volátil pues está altamente ligado al precio del barril de crudo de petróleo, provocando variaciones importantes en las industrias que trabajan con este material y que finalmente repercuten en el consumidor final. Por otro lado, la economía del CB supone retos importantes en materia de sostenibilidad debido al origen fósil de las materias primas, y al desafío asociado con su recuperación una vez terminada la vida útil del producto elaborado con CB. Con base en lo anterior, este trabajo presta especial atención al proceso de pirólisis de neumáticos fuera de uso (NFU) como estrategia de recuperación del CB, y expone algunas de las aplicaciones que actualmente se vienen estudiando para la incorporación del negro de carbono recuperado (rCB) en diferentes sectores productivos. Asimismo, se resaltan los desafíos asociados no solo con el proceso de pirólisis mencionado, sino también con el rCB de cara a su uso como alternativa al CB comercial.

In this work, a thermogravimetric analyser was used to assess the pyrolysis kinetics of pineapple, orange and mango peel wastes and agro-industrial by-products, rice husk and pine wood. Five isoconversional methods (KAS, FWO, Starink, Vyazovkin and Friedman) and one model-fitting method (DAEM) accurately fitted the experimental data at three heating rates (5, 10 and 20 °C/min) between 10% and 90% conversion. These methods agree with the trends shown by the activation energy (Ea) distribution calculated, with fluctuations between 150 and 550 kJ/mol. The fluctuations of Ea in the whole range of conversion, in addition to a higher number of relevant reactions obtained by DAEM for fruit peel samples compared to agro-industrial samples, are associated with a higher extractive content in the peels. Kinetic parameters fitted by DAEM were successfully verified at the highest heating rate studied.

This paper reports the performance of a spark ignition engine using gasoline blended with an upgraded bio-oil rich in aromatics and ethanol. This upgraded bio-oil was obtained using a two-step catalytic process. The first step comprised an in-situ catalytic pyrolysis process with CaO in order to obtain a more stable deoxygenated organic fraction, while the second consisted of a catalytic cracking of the vapours released using ZSM-5 zeolites to obtain an aromatics-rich fraction. To facilitate the mixture between bio-oil and gasoline, ethanol was added. The behaviour of a stationary spark ignition engine G12TFH (9600 W) was described in terms of fuel consumption and electrical efficiency. In addition, gaseous emissions and polycyclic aromatic hydrocarbon (PAH) concentrations were determined. Trial tests suggested that it is possible to work with a blend of gasoline, ethanol and bio-oil (90/8/2 vol%, herein named G90E8B2) showing similar fuel consumption than pure gasoline (G100) at the same load. Moreover, combustion could be considered more efficient when small quantities of ethanol and organic bio-oil are simultaneously added. A reduction, not only in the PAH concentrations but also in the carcinogenic equivalent concentrations, was also obtained, decreasing the environmental impact of the exhaust gases. Thus, results show that it is technically feasible to use low blends of aroma-rich bio-oil, ethanol and gasoline in conventional spark ignition engines.

This work studies the gasification of char derived from waste tire pyrolysis (pCB) by using a thermogravimetric analyzer under CO2/N2 atmospheres (20/80, 25/85 and 30/70 vol%) at different temperatures (825 °C, 850 °C, 875 °C, 900 °C and 925 °C). The main goal is the assessment of three different kinetic models for predicting not only the conversion (X) versus time (t) curve, but also the reaction rate (dX/dt) versus conversion (X) one, with high accuracy. At this respect, the Changing Grain Size Model (CGSM), the Random Pore Model (RPM) and a new model based on the RPM named the Hybrid Modified Random Pore Model (HMRPM) were used. The three models were fitted and the kinetic parameters such as the apparent kinetic constant (Ki(T,pj)), the reaction order (n), the activation energy (Ea) and the pre-exponential factor (A) were determined. The results suggest that the HMRPM is the model with better fitting because its ability to reproduce both conversion (X) and reaction rate (dX/dt); and hence, it is reliable to be integrated in both particle and reactor models, i.e. when the process is being designed and scaled-up. A drastically decrease in the reaction rate at the first stage of conversion (<20%) suggests a possible effect of volatile matter and inorganic compounds contained into the pCB. The n, Ea and A were found to be 0.543, 147.27 kJ/mol and 4.547 × 105 s−1, respectively.

Pyrolysis offers the possibility to convert waste tires into liquid and gaseous fractions as well as a carbon-rich solid (CBp), which contains the original carbon black (CB) and the inorganic compounds used in tire manufacture. Whilst both liquid and gaseous fractions can be valorized without further processing, there is a general consensus that CBp needs to be improved before it can be considered a commercial product, seriously penalizing the pyrolysis process profitability. In this work, the CBp produced in a continuous pyrolysis process was demineralized (chemical leaching) with the aim of recovering the CB trapped into the CBp and thus, producing a standardized CB product for commercial purposes. The demineralization process was conducted by using cheap and common reagents (HCl and NaOH). In this sense, the acid treatment removed most of the mineral matter contained in the CBp and concentration was the main parameter controlling the demineralization process. An ash content of 4.9 wt% was obtained by using 60 min of soaking time, 60 °C of temperature, 10 mL/g of reagent/CBp ratio and HCl 4 M. The demineralized CBp (dCBp) showed a carbon content of 92.9 wt%, while the FRX analysis indicated that SiO2 is the major component into the ash. The BET surface area was 76.3 m2/g, and textural characterizations (SEM/EDX and TEM) revealed that dCBp is composed by primary particles lower than 100 nm. Although dCBp showed a low structure, the surface chemistry was rich in surface acidic groups. Finally, dCBp was used in Styrene Butadiene Rubber (SBR) compounding, probing its technical feasibility as substitute of commercial CB N550.

Tire pyrolysis liquid (TPL)/diesel fuel blend (50/50 vol.%) was fed in a residential boiler unit of 29.1 kW of nominal power, assessing its potential use as alternative heating fuel oil (HFO) for domestic heating. Process performance was compared to that observed for conventional diesel fuel. Both, 50/50 blend and reference diesel fuel were tested at three different positions of the screw which regulates the fuel–air ratio (optimized for diesel fuel). Different operating parameters, such as water and exhaust temperature profiles and boiler efficiency, were evaluated. In addition, concentrations of pollutant gases (CO, NOx and THC) and particulate matter (PM) through total number of particles were measured. The study was carried out under the most critical transient process for any thermal machine: the start-up. Regarding to the fuel effect, the 50/50 blend gives thermal efficiencies slightly higher compared to those found for diesel fuel at all positions tested. In addition, both CO and THC concentrations were slightly lower for the alternative fuel compared to those found for the conventional fuel, being more representative at the lower relative fuel ratio (position 5). However, PM concentrations for 50/50 blend were higher to those found for diesel fuel at all positions of the regulator screw. This work demonstrates the great potential for using a high proportion of TPL fuel blended with diesel fuel without the need of modifying original regulation parameters of boiler, although some properties of TPL should be improved in order to decrease the PM concentrations.

This paper shows the maximum limit on syngas composition obtained from volatiles released in waste tire pyrolysis when they are submitted to an air–steam partial oxidation process. Thus, from mass and energy balances and a stoichiometric equilibrium model, syngas composition and reaction temperature as well as some process parameters were predicted by varying both the equivalence ratio (ER) and the steam to fuel ratio (SF). In addition, pyrolysis experiments were performed using a continuous auger reactor, and the influence of pyrolysis temperature on composition of both volatiles and char was studied. Consequently, the resulting syngas characteristics were correlated with the pyrolysis temperature. The stoichiometric equilibrium model showed that an ER down to 0.4 is a practical limit to perform the air–steam partial oxidation process. When the process is carried out only with air, volatiles obtained at high pyrolysis temperature lead to lower reaction temperature and higher LHV of syngas in comparison with those found at low pyrolysis temperature. The H2 production is favored between 0.20 and 0.40 of ER and seems to be more influenced by the H/C ratio than by the water gas-shift reaction. On the other hand, the steam addition shows a more notable effect on the H2 production for volatiles obtained at the highest pyrolysis temperature (600 °C) in agreement with the lower reaction temperature under these experimental conditions. This thermodynamic analysis provides essential data on the optimization of syngas production from volatiles released in waste tire pyrolysis prior to run any test.

[EN] Waste tires have been valorized by pyrolysis using a pilot scale facility with a nominal capacity of 150 kWth. More than 500 kg of shredded waste tires were pyrolyzed at 550 ºC using a continuous auger reactor. The char fraction produced, herein named pyrolytic carbon black (CBp) was characterized and submitted to different acidification/basification treatments in order to obtain similar properties to those of commercial carbon blacks. Elemental and proximate analyses, surface area and Hg porosimetry were used to investigate the properties of the CBp. It was observed that these treatments decreased the concentration of inorganic compounds without detriment of the textural properties. The ash content decreased from 14.9 wt% up to 3.0 wt.%, by using commercial and cheap reagents used in the chemical industry. The CBp was compared with those of commercial carbon blacks of the N300 series., [ES] Neumáticos usados fueron valorizados por medio del tratamiento termoquímico de pirólisis usando una instalación a escala piloto de 150 kWth de capacidad nominal. Más de 500 kg de neumáticos fueron pirolizados en un reactor continuo de tipo tornillo a 550ºC. La fracción sólida producida, llamada aquí negro de carbón pirolítico (NCP), fue caracterizado en términos de análisis próximo y elemental, área BET y porosimetría de Hg. Asimismo, el NCP fue sometido a diferentes tratamientos de acidificación/basificación con el fin de obtener un sólido carbonoso con propiedades similares a los negros de carbono (NC) comerciales. Se observó que estos tratamientos disminuyen la concentración de compuestos inorgánicos sin detrimento de las propiedades texturales. Así, mediante el uso de reactivos comerciales y baratos, usuales en la industria química, el contenido de cenizas del NCP fue reducido en un 80%, pasando del 14.9 al 3% (en peso) y presentó propiedades similares a los NC comerciales de la serie N300.

A tire pyrolysis liquid (TPL) fuel produced in a continuous auger reactor on pilot scale was blended at 5 vol.% (5TPL) with commercial diesel fuel (100D) and tested in a 4-cylinder, 4-stroke, turbocharged, intercooled, 2.0 L Nissan diesel automotive engine (model M1D) with common-rail injection system. The engine performance and exhaust emissions were obtained for both the 5TPL blend and the commercial diesel fuel. Experiments were conducted in four operating modes that simulate the New European Driving Cycle (NEDC). Both brake specific fuel consumption and brake thermal efficiency seemed to be deteriorated by the composition and the properties of the TPL blend at low engine load, while at higher engine load the values of these parameters were almost equal for both fuels. Total hydrocarbon (THC) emissions followed the same pattern than that of the specific fuel consumption since they were higher for 5TPL at low engine load but similar for both fuels when the engine load increased. NOx emissions were higher for 5TPL than those for 100D in three operating modes (U10, EU8 and EU16), while no significant differences were found in the other mode (U9). In addition, 5TPL led to higher smoke opacity respect to those found for 100D in all operating modes. Combustion duration was slightly longer for 5TPL than 100D. This work could be considered as a contribution for strengthening and encouraging the waste tire pyrolysis for the production of liquid fuels which could be used in automotive engines in very limited concentrations.

This work shows the technical feasibility for valorizing waste tires by pyrolysis using a pilot scale facility with a nominal capacity of 150 kWth. A continuous auger reactor was operated to perform thirteen independent experiments that conducted to the processing of more than 500 kg of shredded waste tires in 100 h of operation. The reaction temperature was 550 °C and the pressure was 1 bar in all the runs. Under these conditions, yields to solid, liquid and gas were 40.5 ± 0.3, 42.6 ± 0.1 and 16.9 ± 0.3 wt.% respectively. Ultimate and proximate analyses as well as heating value analysis were conducted for both the solid and liquid fraction. pH, water content, total acid number (TAN), viscosity and density were also assessed for the liquid and compared to the specifications of marine fuels (standard ISO 8217). Gas chromatography was used to calculate the composition of the gaseous fraction. It was observed that all these properties remained practically invariable along the experiments without any significant technical problem. In addition, the reaction enthalpy necessary to perform the waste tire pyrolysis process (907.1 ± 40.0 kJ/kg) was determined from the combustion and formation enthalpies of waste tire and conversion products. Finally, a mass balance closure was performed showing an excellent reliability of the data obtained from the experimental campaign.

Pyrolysis is becoming a promising alternative to tackle the waste disposal problem related to used tires as well as for the production of alternative liquid fuels. However, the practical applicability of the products obtained from waste tire pyrolysis has been rather limited. This work aims to increase the knowledge about some key properties of the tire pyrolysis liquid (TPL) obtained in a continuous auger reactor on pilot scale, and its blends with diesel fuel (D). Kinematic viscosity, density, heating value, oxidation stability, lubricity, water content, cold filter plugging point (CFPP), and smoke point have been measured for different TPL/D blends. Values for both pure fuels and blends have been compared to the requirements established for diesel fuel (standard EN 590) and to other TPL properties data reported in literature. Additionally, the flash point, the distillation curve, the calculated cetane index (CCI), and the total acid number (TAN) have also been determined for the pure fuels. These properties show the useful window for the utilization of TPL because they indicate its quality as a fuel in diesel engines or other power systems. Mixing rules for calculating some key properties of TPL/D blends as a function of TPL content have also been used in order to model the blend behavior.

Co-pyrolysis of forestry wastes and waste tyres is carried out using different facilities: a fixed bed reactor and a continuous auger reactor. Remarkably, only one phase is found in the liquid fraction, which is not achieved by mixture of the pure liquids. In addition, positive effects between waste tyre and biomass are evidenced, being more notable even synergetic in the auger reactor. It is found that whilst acidity, density and oxygen content decrease, pH and calorific value increase with respect to the merely biomass pyrolysis liquid, leading to upgraded bio-oil. Upgrading process is linked to the presence of radical interactions between waste tyres and biomass pyrolysis products. In addition, it is observed that the addition of waste tyres to the feedstock blend is significantly decreasing the amount of aldehydes and phenolic compounds, which is beneficial for improving the stability of the new bio-oils. © 2013 Elsevier B.V.

Wood catalytic pyrolysis using calcium-based materials was studied in an auger reactor at 450 °C. Two different catalysts, CaO and CaO·MgO were evaluated and upgraded bio-oils were obtained in both cases. Whilst acidity and oxygen content remarkable decrease, both pH and calorific value increase with respect to the non-catalytic test. Upgrading process was linked to the fact that calcium-based materials could not only fix the CO2-like compounds but also promoted the dehydration reactions. In addition, process simulation demonstrated that the addition of these catalysts, especially CaO, could favour the energetic integration since a lowest circulation of heat carrier between combustor and auger reactor should be needed. An energy self-sustained system was obtained where thermal energy required for biomass drying and for pyrolysis reaction was supplied by non-condensable gas and char combustion, respectively.

The thermal behaviour of solid particles of plastic, tyre, coal and biomass as feedstock in pyrolysis processes was studied. The samples were pyrolyzed in a thermogravimetric analyzer in nitrogen atmosphere (surface flow rate 2.65·10− 3 m/s) at two different heating rates (5 and 10 °C/min) with temperatures ranging from 150 to 950 °C. This paper shows the successful application of the distributed energy model to study the effects of dynamic experiments on the solid pyrolysis, in particular, to ABS plastic and tyre rubber for the first time. In addition, the reaction model algorithm used was successfully implemented together with a heat transfer model to predict temperature profiles in the particle and to explore the effects of both solid characteristics and process conditions on the pyrolysis. Within the process conditions studied (particle size, inlet feedstock temperature, reactor temperature and global heat transfer coefficient) the particle size was the most influencing one. From the solid characteristics, the main influence in the particle behaviour was attributed to the characteristic devolatilisation obtained in thermobalance showing the physicochemical properties a weak influence on it.