Pyrolysis of Polyolefins in a Conical Spouted Bed Reactor: A Way to Obtain Valuable Products

The amount of waste plastic increases every single year, which causes a critical environmental issue. Polyolefins (mainly high‐ and low‐density polyethylene and polypropylene) are the most common types of plastics, accounting for 60 wt% of the plastic waste. Pyrolysis, the thermal degradation in an inert atmosphere, is considered to be one of the most appealing technologies for the recycling of plastic materials. The conical spouted bed reactor is suitable for the pyrolysis of plastic waste due to its ability to avoid agglomeration problems that may be caused by the melted plastic. The pyrolysis process may be carried out at different temperatures and with or without the presence of catalysts in the reaction environment in order to streamline product distribution. The resulting products are hydrocarbons: non‐condensable gases (C1–C4), gasoline fraction, diesel fraction, and waxes. These fractions might be used directly as feed streams for refinery units or as pools to be mixed with other streams from refineries

A CONICAL SPOUTED BED REACTOR FOR THE VALORISATION OF WASTE TIRES

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 distribution. Thus, pyrolysis oil yield was reduced from 64.3 wt% at 425 ºC to 55.9 wt% at 600 ºC. However, the quality of carbon black was improved operating at high temperatures (increasing BET surface area values). High yields of certain interesting chemicals have been obtained in the liquid fraction, such as limonene (19.3 wt%), isoprene (5.7 wt%) and styrene (6.1 wt%)

Evaluating catalytic (gas-solid) spectroscopic cells as intrinsic kinetic reactors: Methanol-to-hydrocarbon reaction as a case study

Commercial spectroscopic gas-solid cell reactors are routinely used to analyze the dynamics of the catalyst (catalyst pelletized as a disc) structure and retained/adsorbed species using multiple operando techniques. These instruments have revolutionized the understanding of many catalytic reactions, including the methanol-to-hydrocarbon reactions. We propose a reaction engineering framework to evaluate spectroscopic cells based on (a) analyzing the fluid dynamic performance, (b) comparing their performance with a reference packed-bed reactor, and (c) the assessment of the external and internal mass transfer limitations. We have used a Specac HTHP and a Linkam THMS600 cell reactors coupled with the corresponding gas conditioning, spectroscopic, and mass spectrometry apparatuses. Our results reveal that these cells approach a perfect mixing only with several equivalent tanks in series and they are reliable at low catalyst loadings (thin disc) and high flowrates (low spacetimes). Under these conditions, we can avoid external-internal mass transfer limitations and fluid dynamic artifacts (e.g., bypassing or dead/stagnant volume zones), obtaining intrinsic kinetics with the corresponding operando spectroscopic signatures. The proposed methodology allows to understand the influence of process parameters and potential design modifications on the observed kinetic performance.This work was possible due to the financial support of the Ministry of Economy, Industry, and Competitiveness of the Spanish Government (project CTQ2016-79646-P, cofounded with ERDF funds), the Basque Government (projects IT1218-19 and IT1645-22), and the King Abdullah University of Science and Technology (KAUST, project BAS/1/1403). J.V. is grateful for the fellowship granted by the Ministry of Economy, Industry, and Competitiveness of the Spanish Government (BES-2014-069980). The authors are grateful for the technical and human support provided by IZO-SGI SGIker of the University of the Basque Country (UPV/EHU) and European funding (ERDF and ESF)

Poliolefinen pirolisia iturri-ohantze konikoan

The amount of waste plastic increases every single year, which causes a critical environmental issue. Polyolefins (mainly high and low density polyethylene and poly- propylene) are the most common types of plastics, accounting for 60 wt% of the plastic waste. Pyrolysis, the thermal degradation in an inert atmosphere, is considered to be one of the most appealing technologies for the recycling of plastic materials. The conical spouted bed reactor is suitable for the pyrolysis of plastic waste due to its ability to avoid agglomeration problems that may be caused by the melted plastic. The pyrolysis process may be carried out at different temperatures and with or without the presence of catalysts in the reaction environment in order to streamline the product distribution. The resulting products are hydrocarbons: non-condensable gases (C1-C4), gasoline fraction, diesel frac- tion, and waxes. These fractions might be used directly as feed streams for refinery units or as pools to be mixed with other streams from refineries.; Hondakin plastikoen kantitatea gero eta handiagoa da eta horrek arazo larria sortzen du. Hondakin plastikoen artean ugarienak, %60 inguruko masa-proportzioan, poliolefinak dira (dentsitate altuko eta baxuko polietilenoa eta polipropilenoa). Pirolisi bidezko birziklatzea aukera interesgarria da plastikoen materiala berreskuratzeko. Pirolisia atmosfera inertean gauzatzen den degradazio termikoko prozesua da. Iturri-ohantze konikoak propietate egokiak ditu material plastikoen pirolisia egiteko, batez ere plastikozko partikula urtuek eragin ditzaketen aglomerazio-arazoak ekiditeko. Pirolisia tenperatura ezberdinetan, katalizatzailerik gabe edo katalizatzaile ezberdinak erabiliz egin daiteke, lortzen diren produktuen banaketa aldatzeko. Poliolefinen pirolisian lortzen diren produktuak hidrokarburoak dira, hala nola, C1-C4 gasak, gasolina frakzioa, gasolio frakzioa edota ezkoak. Frakzio horiek findegietan ohiko korronteekin elkar daitezke edo bertako unitateetako elikadurak osa ditzakete