Maite Artetxe

Universidad del País Vasco / Euskal Herriko Unibertsitatea | UPV/EHU · Chemical Engineering

This study evaluates the potential of several biomasses differing in nature and composition for their valorization by pyrolysis and in line oxidative steam reforming. The first task involved the fast pyrolysis of the biomasses in a conical spouted bed reactor (CSBR) at 500 °C, in which product yields were analyzed in detail. Then, the oxidative ste...

The oxidative fast pyrolysis of plastics was studied in a conical spouted bed reactor with a fountain confiner and draft tube. An inexpensive fluid catalytic cracking (FCC) spent catalyst was proposed for in situ catalytic cracking in order to narrow the product distribution obtained in thermal pyrolysis. Suitable equivalence ratio (ER) values requ...

This study analyzes the two step process of biomass pyrolysis and in-line steam reforming for the production of H2. In order to evaluate the effect of the volatile composition on the commercial Ni/Al2O3 catalyst performance and stability, biomass pyrolysis step was conducted at different temperatures (500-800 ºC). The analysis of the deactivated ca...

The fast deactivation of the reforming catalyst greatly conditions H2 production from biomass. In order to alleviate this problem, use of conditioning catalysts in a previous conditioning step has been proposed to modify the pyrolysis volatile stream reaching the reforming catalyst. The experimental runs have been conducted in a two-step reactor sy...

Fast pyrolysis combined with oxidative steam-reforming is an attractive approach for the large scale production of renewable H2. Although O2 addition contributes to reducing energy requirements and coke formation on the catalyst surface, its presence in the reaction environment negatively impacts H2 production with a reduction up to 24% under autot...

The activity and stability of a 10 wt%NiO/CaO catalyst were tested in the sorption enhanced ethanol steam reforming (SEESR) in a fluidized bed reactor. The effect of temperature in the 600-750 ºC range was analyzed and the performance of the catalyst at 700 ºC was assessed by conducting cycles of SEESR reaction and CO2 desorption. At zero time on s...

The steam pyrolysis of pinewood sawdust has been conducted in a bench scale plant provided with a conical spouted bed reactor (CSBR). This process is of uttermost relevance for the in-line valorisation of pyrolysis volatiles, specifically for their catalytic steam reforming for hydrogen production. The influence of temperature on he product yields...

This paper presents a method that instructors have designed and implemented to form balanced teams based on Belbin's roles, with the aim of boosting positive interdependence and individual accountability within the teams and improving their performance in a project-based learning environment. Students’ performance has been measured through the scor...

Biomass pyrolysis and the in-line catalytic cracking of the pyrolysis volatile stream has been approached in this study. The pyrolysis step was carried out in a conical spouted bed reactor at 500 °C, whereas the inert sand or the cracking catalysts (γ-Al2O3, spent FCC and olivine) were placed in a fixed bed reactor at 600 °C. Product analysis was c...

Continuous catalytic cracking of polyethylene over a spent fluid catalytic cracking (FCC) catalyst was studied in a conical spouted bed reactor (CSBR) with fountain confiner and draft tube. The effect of temperature (475–600 °C) and space‐time (7–45 gcat min gHDPE⁻¹) on product distribution was analyzed. The CSBR allows operating with continuous pl...

The environmental problems related with the management of waste plastics require the development of efficient valorization routes. This chapter deals with three different strategies aimed at the selective conversion of plastics to chemicals and hydrogen following the two-step continuous processes. Flash pyrolysis performed in a conical spouted bed...

The performance and stability of different Ni supported catalysts have been studied in a continuous bench scale plant fitted with a conical spouted bed reactor for biomass pyrolysis at 500 °C and a fluidized bed reactor for the in line catalytic steam reforming of pyrolysis volatiles at 600 °C. The metal oxides selected as Ni supports have been Al2...

The activity and stability of a Ni/ZrO2 catalyst have been studied in a continuous bench scale plant, in which biomass has been pyrolysed at 500 °C in a conical spouted bed reactor and the outlet volatile stream has been subjected to catalytic steam reforming at 600 °C in a fluidized bed reactor. The influence of space time has been analyzed, and b...

Teammates in a Project Based Learning (PBL) methodology do not all start with the same motivation, expectations or self-commitment, which can lead to disappointing learning experiences. Thus, the main difficulties in cooperative learning are promoting positive interdependence and individual accountability. This work aims to analyze whether monitori...

The effect of reforming conditions (temperature, space time and steam/biomass ratio (S/B)) has been studied in the continuous biomass pyrolysis and in-line catalytic steam reforming process in order to establish suitable conditions for attenuating the deactivation of a commercial Ni catalyst by coke deposition. The experiments have been performed i...

Pyrolysis of high density polyethylene (HDPE) has been carried out in a conical spouted bed reactor (500 degrees C) and the volatiles have been reformed in-line over a Ni commercial catalyst in a fluidized bed reactor. The evolution of reaction indices (conversion, H-2 yield and other gaseous product yields) with time on stream has been studied und...

The current review provides an assessment of the main waste plastics valorization routes to produce syngas and H2, thus covering different gasification strategies and other novel alternative processes, such as pyrolysis and in-line catalytic steam reforming. The studies dealing with plastics gasification are in general scarce. However, due to the k...

The influence the support has on the performance of Ni catalysts used in the reforming of biomass fast pyrolysis volatiles has been assessed. Accordingly, five catalysts have been prepared by wet impregnation method, namely Ni/Al2O3, Ni/SiO2, Ni/MgO, Ni/TiO2 and Ni/ZrO2. These catalysts have been characterized by nitrogen adsorption/desorption, X-r...

The performance of an original two-step reaction system (pyrolysis and in-line reforming) was assessed in the hydrogen production from different plastics (polyethylene, polypropylene, polyethylene terephthalate and polystyrene) and their mixture. The pyrolysis step was performed in a conical spouted bed reactor at 500 °C, whereas the reforming of p...

The kinetics of the steam reforming of HDPE pyrolysis volatiles is studied on a Ni commercial catalyst in a fluidized bed reactor in-line with the pyrolysis reactor (a conical spouted bed reactor at 500 ºC). Steam reforming reactions have been carried out under the following conditions: 600-700 ºC and space time 0-16.7 gcat min gHDPE-1. Based on th...

The continuous increase in the generation of waste plastics together with the need for developing more sustainable waste management policies have promoted a great research effort dealing with their valorization routes. In this review, the main thermochemical routes are analyzed for the valorization of waste polyolefins to produce chemicals and fuel...

This work focuses on the removal of the tar derived from biomass gasification by catalytic steam reforming on Ni/Al2O3 catalysts. Different tar model compounds (phenol, toluene, methyl naphthalene, indene, anisole and furfural) were individually steam reformed (after dissolving each one in methanol), as well as a mixture of all of them, at 700 °C u...

The continuous pyrolysis-reforming of pine sawdust and high density polyethylene mixtures (25, 50 and 75 wt% HDPE) has been performed in a two-stage reaction system provided with a conical spouted bed reactor (CSBR) and a fluidized bed reactor. The influence HDPE co-feeding has on the conversion, yields and composition of the reforming outlet strea...

The valorization of waste high density polyethylene (HDPE) for hydrogen production has been studied in a two-step process, comprising pyrolysis and subsequent steam reforming of the volatiles produced in the first step. Particularly, this work focuses on the deterioration mechanisms (sintering and coke deposition) of the Ni commercial catalyst used...

Lan honetan poliolefinetatik abiatuta olefinak ekoizteko bi estrategia ezberdin konparatzen dira. Bi kasuetan lehen etapan iturri ohantze konikoko erreaktorean plastikoaren pirolisia egin da. Bigarren etapari dagokionez bi aukera ezberdin aztertu dira pirolisian sorturiko hegazkorren cracking-a egiteko. Alde batetik, ohantze finkoan cracking katali...

Catalytic steam reforming of phenol over Ni/Al2O3 catalyst with 10 wt% of Ni loading was carried out in a fixed bed reactor. The effect of temperature (650–800 °C), reaction time (20–80 min) and catalyst amount (0–2 g corresponding to 0–4.5 gcat h gphenol−1) on carbon conversion, H2 potential and catalyst deactivation was studied. High efficiency o...

Hydrogen production from polystyrene (PS) has been studied following continuous pyrolysis and in-line steam reforming. The first step was carried out at 500 °C in a conical spouted bed reactor and the subsequent reforming one was performed in a fluidized bed reactor on a commercial Ni catalyst at 700 °C. The effect space time and time on stream hav...

Catalytic steam reforming of n-hexane, 1-hexene, tetradecane and toluene over Ni a commercial catalyst has been carried out in a fluidized bed reactor at 700 °C. These compounds have been selected as model compounds of the volatiles formed in the pyrolysis of waste plastics in order to study in detail the performance of the catalyst in the pyrolysi...

Sewage sludge fast pyrolysis bio-oil, produced in a conical spouted bed reactor (CSBR) in the 450-600 °C range, has been characterized. On the one hand, the effect of temperature on bio-oil composition has been analyzed by means of online chromatography and, furthermore, the ultimate analysis and the higher heating value of each liquid have been de...

A continuous process has been developed consisting in the flash pyrolysis (500 °C) of high density polyethylene (HDPE) in a conical spouted bed reactor (CSBR) followed by steam reforming in a fluidized bed reactor (Ni commercial catalyst). The effect reforming temperature in the 600–700 °C range, space time from 2.1 to 20.8 gcat min gHDPE−1 and ste...

Steam gasification (900 °C) of high density polyethylene (HDPE) in a conical spouted bed reactor (CSBR) followed by steam reforming in a fixed bed reactor (Ni commercial catalyst) has been carried out. The effect reforming temperature in the 600-700 °C range has on product yields and gas composition as well as on the amount and nature of the coke d...

Steam pyrolysis (500 °C) of high density polyethylene (HDPE) in a conical spouted bed reactor followed by a steam reforming (700 °C) in a fixed bed reactor (Ni commercial catalyst) has been carried out for obtaining a syngas stream rich in H2. The product yields obtained in the pyrolysis of HDPE using steam are very similar to the previous ones wit...

Continuous pyrolysis of polystyrene has been studied in a conical spouted bed reactor with the main aim of enhancing styrene monomer recovery. Thermal degradation in a thermogravimetric analyser was conducted as a preliminary study in order to apply this information in the pyrolysis in the conical spouted bed reactor. The effects of temperature and...

Hydrogen production from pyrolysis-catalytic steam reforming of pine sawdust has been investigated using two subsequent reactors: i) a conical spouted bed reactor for biomass pyrolysis at 500 °C, and ii) a fluidized bed reactor for catalytic reforming of volatiles from the pyrolysis step. A commercial Ni reforming catalyst has been used for the ref...

The effect of temperature in the catalytic cracking of HDPE over a spent FCC catalyst on the product distribution has been studied using a two-step reaction system. Thermal pyrolysis of HDPE has been carried out in a conical spouted bed reactor and the volatiles formed (mainly waxes) have been fed in-line into a catalytic fixed bed reactor. An incr...

Principal component analysis is used as a pattern recognition method to find criteria for grouping into lumps the compounds formed in the thermal and catalytic pyrolysis of waste tyres. This information is the stating point for the proposal of simple kinetic schemes that efficiently describe the complex reactions that occur in the pyrolysis process...

Continuous catalytic pyrolysis of high density polyethylene has been carried out for obtaining light olefins in a two step reaction system: (i) thermal pyrolysis in a conical spouted bed at 500 degrees C; (ii) cracking of the volatiles (mainly waxes, C21+) formed in the first step, in a fixed bed reactor using a catalyst based on HZSM-5 zeolite. A...

High density polyethylene (HDPE) cracking has been carried out in a thermal-catalytic two-step unit for the selective production of light olefins. Continuous pyrolysis of HDPE has been conducted in a conical spouted bed reactor at 500 °C, and the volatiles formed (mainly waxes) have been transformed in a downstream fixed bed catalytic reactor at 50...

The catalytic cracking of HDPE (high density polyethylene) at 500 °C using a spent FCC catalyst agglomerated with bentonite (50 wt %) has been studied in a conical spouted bed reactor. The reaction is carried out in continuous regime (1 g min–1 of HDPE is fed) with no bed defluidization problems. The results obtained, namely, total conversion, and...

The continuous catalytic pyrolysis of high density polyethylene (HDPE) has been carried out in a two-step reaction system involving a pyrolysis conical spouted bed reactor followed by a catalytic fixed bed reactor. The good performance of the conical spouted bed reactor has allowed using a low temperature in thermal cracking (500 °C) without deflui...

A two-step process has been used for the selective production of light olefins by the thermal cracking of high-density polyethylene. The plastic has been continuously fed into a conical spouted-bed reactor (CSBR) operating at 500 °C, which yields 93 wt % of waxes (C21+) and C12–C21 hydrocarbons. The volatile product stream has been cracked downstre...

The production of activated carbons derived from waste tires has been carried out using steam and carbon dioxide as activation agents. The effect of temperature and activation time over the carbons prepared has been studied. The material subjected to activation has been char or residual carbon black obtained by continuous flash pyrolysis of waste t...

A commercial FCC catalyst based on a zeolite active phase has been used to perform the valorisation of waste tires by in situ catalytic pyrolysis. The process has been carried out in a conical spouted bed reactor provided by a continuous feeding system. The catalyst has been subjected to a steaming treatment in order to maximize diesel fraction. Hi...

The thermal and catalytic cracking of plastic waste has been regarded as one of the most feasible plastic recycling method at industrial scale. Three catalysts based on HZSM-5 zeolites with a ratio of SiO2/Al2O3 = 30, 80, and 280 were prepared and agglomerated by wet extrusion with bentonite (30 wt %) and with inert alumina (45 wt %). Continuous py...

The continuous flash pyrolysis of lignocellulosic biomass under atmospheric and vacuum conditions (0.25 atm) has been studied in a bench-scale plant provided with a conical spouted bed reactor. A previous kinetic study has been carried out in thermobalance, and the kinetic data have been fitted to a three parallel and independent reaction model by...

The pyrolysis of high-density polyethylene (HDPE) has been carried out in the range between 500 and 700 °C in continuous mode in a pilot-plant unit equipped with a conical spouted bed reactor. The products have been grouped into the lumps of gas (C4–), gasoline (C5–C11), diesel (C12–C20), and waxes (C21+). The product yields and compositions of the...

The effect of operating conditions on product yields and compositions has been studied in the catalytic cracking of polyolefins (high- and low-density polyethylene and polypropylene) in a conical spouted bed reactor. The catalyst has been prepared by agglomerating an HZSM-5 zeolite (SiO2/Al2O3 = 30) with bentonite and alumina. The study has been ca...

The catalytic cracking of high density polyethylene (HDPE) has been carried out at 500 C in a conical spouted bed reactor with two catalysts prepared with HZSM-5 zeolites with SiO2/Al2O3 ratios of 30 and 80. The polyethylene has been fed continuously (1 g min(-1)) over 10 h to a 30g catalyst bed. The results show the good performance of the conical...

A pilot plant provided with a conical spouted bed reactor has been used for the valorisation of waste tires by thermal pyrolysis in continuous mode. The effect of pyrolysis temperature on product distribution and properties has been studied in the temperature range from 425 to 600 ºC. This variable has proven to have an important effect on product...

The continuous pyrolysis of waste tires under vacuum conditions (25 and 50 kPa) has been studied in a pilot plant equipped with a conical spouted bed reactor and operating with continuous feed at 425 and 500 degrees C. The effects of vacuum on product distribution and properties have been studied. The main effect of vacuum is an increase in the die...

The pyrolysis of poly-(methyl methacrylate) (PMMA) has been studied in a pyrolysis plant provided with a conical spouted bed reactor. This reactor is an interesting technology for the pyrolysis of waste plastics due to its excellent hydrodynamic behaviour and its high heat transfer and versatility. A previous kinetic study was carried out in thermo...

Pyrolysis of scrap tires has been studied at 425 and 500°C and three pressure levels, atmospheric one 0.5 and 0.25 atm. The experimental runs have been carried out in a pilot plant conical spouted bed reactor provided with a system for continuous feeding of scrap tires. The feeding rate was 3 g/min and the mass fed in each run was 100 g. The main e...

Continuous pyrolysis of poly-(ethylene terephthalate) (PET) was performed in a conical spouted-bed reactor. This reactor is especially suitable for this process, because of its excellent hydrodynamic behavior and its versatility. An optimization of the operating conditions has been performed to avoid particle agglomeration and defluidization, given...

Pyrolysis is regarded as one of the most promising technologies for the valorization of waste materials and to obtain chemicals and alternative fuels to fossil ones. Pyrolytic oils are a very complex mixture hydrocarbons or oxygenated compounds with a wide distribution of molecular weights. High Performance Liquid Chromatography is a suitable way t...

A study has been carried out using HZSM-5, HY and Hβ zeolite-based catalysts in the pyrolysis of high density polyethylene (HDPE) continuously fed into a conical spouted bed reactor (CSBR) at 500 °C and atmospheric pressure, with the aim being to assess the yields and composition of the main products (both light olefins and automotive fuel hydrocar...

Activation of tyre char has been carried out using steam as activation agent, and the effect of temperature and activation time has been studied. The char samples used in the activation have been obtained by continuous flash pyrolysis carried out in a conical spouted bed reactor at 500°C. The activation has been carried out at 850 and 900°C in a fi...

The challenge of the tyre pyrolysis process is to make profitable the pyrolysis products by finding a commercial application. The pyrolysis liquid products may be used directly as fuel or they may be added to a refinery feed. The solid residue can be burnt to provide energy for the process, but reutilization as carbon black or its upgrading to obta...