Tire pyrolysis char: Processes, properties, upgrading and applications

Waste tires are solid wastes with large annual output and with the potential for great harm to the environment. The pyrolysis of waste tires can recycle energy and produce reusable products. Although there are many reviews in the literature in regard to the pyrolysis characteristics of waste tires, no one paper focuses on reviewing and summarizing the tire char. This paper critically appraises the achievements of earlier reports and literature and assesses the current state-of-the-art for the production and application of tire char from waste tires. Initially, the thermal decomposition behavior of different tire rubbers is discussed and compared where it is shown that the different components of waste tire rubber have different thermal degradation characteristics. The influencing factors on the yield and quality of tire char are discussed and assessed in terms of different pyrolysis reactors and technologies, tire type and composition, and a range of pyrolysis process conditions. The composition of the waste tire and pyrolysis conditions are the main factors affecting the distribution of pyrolysis products. Pyrolysis technology and reactor equipment also have an effect on the distribution of pyrolysis products. The physical and chemical structural characteristics of tire char are critically reviewed in detail, including a comparison of the fundamental differences with commercial carbon black and modified tire char (physical activation and chemical activation). Finally, high-value application fields and developmental prospects of tire char are summarized. Through extensive literature review, a novel development was that tire char could be used as a source of gra-phene. The economic analysis of the various tire char applications should be one of the main research directions in the future. The keynote of this review is to promote intensification of waste tire recycling and treatment so that more tire char can be obtained from waste tire pyrolysis and thereby be reused in different applications to obtain more value.This project has received funding from the Science and Technology Exchange Project of China Ministry of Science and Technology (2021- 12-2) and Education Cooperation Project between China and Central Eastern European Countries (2021086) and Shaanxi Provincial Natural Science Foundation Research Program Shaanxi Coal Joint Funding (2019JLZ-12)

Appraisal of agroforestry biomass wastes for hydrogen production by an integrated process of fast pyrolysis and in line steam reforming

The pyrolysis and in line steam reforming of different types of representative agroforestry biomass wastes (pine wood, citrus wastes and rice husk) was performed in a two-reactor system made up of a conical spouted bed and a fluidized bed. The pyrolysis step was carried out at 500 °C, and the steam reforming at 600 °C with a space time of 20 gcatalyst min gvolatiles−1 and a steam/biomass ratio (S/B) of 4. A study was conducted on the effect that the pyrolysis volatiles composition obtained with several biomasses has on the reforming conversion, product yields and H2 production. The different composition of the pyrolysis volatiles obtained with the three biomasses studied led to differences in the initial activity and, especially, in the catalyst deactivation rate. Initial conversions higher than 99% were obtained in all cases and the H2 production obtained varied in the 6.7–11.2 wt% range, depending on the feedstock used. The stability of the catalysts decreased depending on the feedstock as follows: pine wood ≫ citrus waste > rice husk. A detailed assessment of the mechanisms of catalyst deactivation revealed that coke deposition is the main cause of catalyst decay in all the runs. However, the volatile composition derived from the pyrolysis of citrus waste and rice husk involved the formation of an encapsulating coke, which severely blocked the catalyst pores, leading to catalyst deactivation during the first minutes of reaction.his work was carried out with the financial support of the grants PID2022-140704OB-I00 and PID2022-139454OB-I00 funded by MCIU/AEI/10.13039/501100011033 and “ERDF, a way of making Europe”, the grants TED 2021-132056B–I00 and PLEC 2021-008062 funded by MCIN/AEI/10.13039/501100011033 and “European Union NextGenerationEU/PRTR”, and the grants IT1645-22 and KK-2023/00060 funded by the Basque Government. Moreover, this project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 823745

Effect of CeO2 and MgO promoters on the performance of a Ni/Al2O3 catalyst in the steam reforming of biomass pyrolysis volatiles

A Ni/Al2O3 catalyst has been modified incorporating CeO2 and MgO promoters in order to improve its performance in the steam reforming of biomass pyrolysis volatiles. Ni/Al2O3, Ni/CeO2-Al2O3 and Ni/MgO-Al2O3 catalysts have been prepared and fresh and deactivated catalysts have been characterized by N2 adsorption/ desorption, X-ray Fluorescence (XRF), Temperature Programmed Reduction (TPR), X-ray powder diffraction (XRD), Temperature Programmed Oxidation (TPO), Transmission Electron Microscopy (TEM) and a technique based on Fourier Transform Infrared Spectroscopy-Temperature Programmed Oxidation (FTIR-TPO). The results obtained revealed a similar initial activity for the three catalysts tested (conversion higher than 98%), whereas stability has been greatly improved by incorporating CeO2 as promoter, as it enhances the gasification of coke precursors. However, Ni/MgO-Al2O3 catalyst is slightly less stable than Ni/Al2O3, presumably as a result of its lower reducibility due to the formation of MgAl2O4 spinel phase. Catalysts deactivation has been associated with coke deposition, although sintering phenomenon became also evident when the Ni/CeO2-Al2O3 catalyst was tested. The coke deposited on the catalysts does not present any specific morphology, which is evidence of its amorphous structure in the three catalysts studied.This work was carried out with financial support from the Ministry of Economy and Competitiveness of the Spanish Government (CTQ2016-75535-R (AEI/FEDER, UE) and CTQ-2015-69436-R (MINECO/FEDER, UE)), Ministry of Science, Innovation and Universities of the Spanish Government (RTI2018-101678-B-I00 (MCIU/AEI/FEDER, UE)), the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 823745, and the Basque Government (IT1218-19)

Fe/Olivine As Primary Catalyst in the Biomass Steam Gasification in a Fountain Confined Spouted Bed Reactor

The performance of Fe/olivine catalysts was tested in the continuous steam gasification of sawdust in a bench scale plant provided with a fountain confined conical spouted bed reactor at 850 degrees C. Olivine was used as catalyst support and loaded with 5 wt%Fe. The activity and stability of the catalyst was monitored by nitrogen adsorption-desorption, X-ray fluorescence spectroscopy, temperature programmed reduction, X-ray diffraction and X-ray photoelectron spectroscopy techniques, which were conducted before and after the runs. The fountain confined conical spouted bed performs well in the biomass steam gasification with primary catalysts. In fact, this reactor allows enhancing the gas-solid contact, and therefore the catalytic activity by avoiding the elutriation of fine catalyst particles. The uncatalysed efficiency of the gasification process, assessed based on the gas production and composition, H-2 production, tar concentration and composition, and carbon conversion efficiency, was consideraby improved on the Fe/olivine catalyst, with tar reduction being especially remarkable (to 10.4 g Nm(-3)). After 140 min on stream, catalyst deactivation was particularly evident, as tar concentration increased to 19.9 g Nm(-3) (90% of that without catalyst). However, Fe/olivine catalyst was still active for WGS and CH4 steam reforming reactions, with gas and H-2 productions being 1.35 Nm(3) kg(-1) and 5.44 wt%, respectively. Metal iron oxidation to Fe3O4 caused catalyst deactivation, as the reaction environment shifted from oxidizing to reducing conditions due to operational limitations.This work was carried out with financial support from the Spain's Ministries of Science, Innovation and Universities (GN1 RTI2018-098283-J-I00 GN10 (MCIU/AEI/FEDER, UE) and Science and Innovation (PID2019-107357RB-I00 (MCI/AEI/FEDER, UE), the Basque Government (IT1218-19 and KK-2020/00107), and the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 823745. The authors also thank the technical and human support provided by SGIker from UPV/EHU and European funding (ERDF and ESF

A comprehensive review of primary strategies for tar removal in biomass gasification

In the current energy scenario, the production of heat, power and biofuels from biomass has become of major interest. Amongst diverse thermochemical routes, gasification has stood out as a key technology for the large-scale application of biomass. However, the development of biomass gasification is subjected to the efficient conversion of the biochar and the mitigation of troublesome by-products, such as tar. Syngas with high tar content can cause pipeline fouling, downstream corrosion, catalyst deactivation, as well as adverse impact on health and environment, which obstruct the commercialization of biomass gasification technologies. Since the reduction of tar formation is a key challenge in biomass gasification, a comprehensive overview is provided on the following aspects, which particularly include the definition and complementary classifications of tar, as well as possible tar formation and transformation mechanisms. Moreover, the adverse effects of tar on downstream applications, human health or environment, and tar analyzing techniques (online and off-line) are discussed. Finally, the primary tar removal strategies are summarized. In this respect, the effect of key operation parameters (temperature, ER and S/B), catalysts utilization (natural and supported metal catalysts) and the improvement of reactor design on tar formation and elimination was thoroughly analyzed.This work was carried out with the financial support from Spanish Ministries of Science, Innovation and Universities (RTI2018-098283-J-I00 (MCIU/AEI/FEDER, UE)) and Science and Innovation (PID2019-107357RB-I00 (MCIU/AEI/FEDER, UE) and TED2021-132056B-I00 (MCI/AEI/FEDER, UE)) and the Basque Government (IT1645-22). Moreover, this project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 823745

Progress on Catalyst Development for the Steam Reforming of Biomass and Waste Plastics Pyrolysis Volatiles: A Review

[EN]n recent decades, the production of H-2 from biomass, waste plastics, and their mixtures has attracted increasing attention in the literature in order to overcome the environmental problems associated with global warming and CO2 emissions caused by conventional H-2 production processes. In this regard, the strategy based on pyrolysis and in-line catalytic reforming allows for obtaining high H-2 production from a wide variety of feedstocks. In addition, it provides several advantages compared to other thermochemical routes such as steam gasification, making it suitable for its further industrial implementation. This review analyzes the fundamental aspects involving the process of pyrolysis-reforming of biomass and waste plastics. However, the optimum design of transition metal based reforming catalysts is the bottleneck in the development of the process and final H-2 production. Accordingly, this review focuses especially on the influence the catalytic materials (support, promoters, and active phase), synthesis methods, and pyrolysis-reforming conditions have on the process performance. The results reported in the literature for the steam reforming of the volatiles derived from biomass, plastic wastes, and biomass/plastics mixtures on different metal based catalysts have been compared and analyzed in terms of H-2 production.This work was carried out with the financial support from Spain's Ministries of Science, Innovation and Universities (Grant RTI2018-101678-B-I00 (MCIU/AEI/FEDER, UE) and Grant RTI2018-098283-J-I00 (MCIU/AEI/FEDER, UE)) and Science and Innovation (Grant PID2019-107357RB-I00 (AEI/FEDER, UE)) and the Basque Government (Grants IT1218-19 and KK-2020/00107). Moreover, this project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 823745

CeO2 and La2O3 promoters in the steam reforming of polyolefinic waste plastic pyrolysis volatiles on Ni-based catalysts

[EN] Based on the promising results of La2O3 and CeO2 promoted Ni/Al2O3 catalysts in the reforming of biomass pyrolysis volatiles, the performance of these catalysts and the non-promoted one was 2 evaluated in the pyrolysis and in-line steam reforming of polypropylene (PP). The experiments were carried out in a continuous bench scale pyrolysis-reforming plant using two space times of 4.1 and 16.7 gcat min gplastic−1 and a steam/PP ratio of 4. The prepared catalysts and the deposited coke were characterized by N2 adsorption-desorption, X-ray fluorescence (XRF), X-ray diffraction (XRD), temperature programmed oxidation (TPO) and transmission electron microscopy (TEM). The Ni/Al2O3 catalyst showed suitable performance regarding pyrolysis product conversion and hydrogen production, and led to moderate coke deposition. It is to note that La2O3 incorporation remarkably improved catalyst performance compared to the other two catalysts in terms of conversion (> 99 %), hydrogen production (34.9 %) and coke deposition (2.24 wt%).This work was carried out with the financial support from Spain’s ministries of Economy and Competitiveness (CTQ2016-75535-R (AEI/FEDER, UE), Science, Innovation and Universities (RTI2018-101678-B-I00 (MCIU/AEI/FEDER, UE)) and, Science and Innovation PID2019-107357RB-I00 (MCI/AEI/FEDER, UE)), the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 823745, and the Basque Government (IT1218-19 and KK-2020/00107)

A narrative review and expert recommendations on the assessment of the clinical manifestations, follow-up, and management of post-OLT patients with ATTRv amyloidosis

Orthotopic liver transplantation (OLT) was the first treatment able to modify the natural course of hereditary transthyretin (ATTRv) amyloidosis, which is a rare and fatal disorder caused by the accumulation of misfolded transthyretin (TTR) variants in different organs and tissues and which leads to a progressive and multisystem dysfunction. Because the liver is the main source of TTR, OLT dramatically reduces the production of the pathogenic TTR variant, which should prevent amyloid formation and halt disease progression. However, amyloidosis progression may occur after OLT due to wild-type TTR deposition, especially in the nerves and heart. In this review, we discuss the disease features influencing OLT outcomes and the clinical manifestations of ATTRv amyloidosis progression post-OLT to improve our understanding of disease worsening after OLT and optimize the follow-up and clinical management of these patients. By conducting a literature review on the PubMed database, we identified patient characteristics that have been associated with worse post-OLT outcomes, including late-onset V50M and non-V50M variants, age >40 years, long disease duration, advanced neuropathy and autonomic dysfunction, and malnutrition. Regarding post-OLT mortality, deaths occurring within the first year after OLT were mainly associated with fatal graft complications and infectious diseases, whereas cardiovascular-related deaths usually occurred later. Considering the diverse clinical manifestations of ATTRv amyloidosis progression post-OLT, including worsening neuropathy and/or cardiomyopathy, autonomic dysfunction, and oculoleptomeningeal involvement, we present advice on the most relevant tests for assessing disease progression post-OLT. Finally, we discuss the use of new therapies based on TTR stabilizers and TTR mRNA silencers for the treatment of ATTRv amyloidosis patients post-OLT

Tuning pyrolysis temperature to improve the in-line steam reforming catalyst activity and stability

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 °C). The analysis of the deactivated catalysts has also allowed identifying the main bio-oil compounds responsible for catalyst decay (coke precursors). Pyrolysis temperature allows modifying the composition of the volatile stream that is subsequently reformed at 600 °C. An increase in pyrolysis temperature to 800 °C improves considerably the production of both H2 and gaseous stream at the initial reaction stages, reaching values of 12.95 wt% and 2.23 Nm3 kg−1, respectively. Catalyst stability is also considerably improved when pyrolysis temperature is increased due to the lower bio-oil yield and its different composition at high temperatures. Coke was the main cause of catalyst deactivation. Besides, the nature of the coke deposited is influenced by the composition of the pyrolysis volatiles, with encapsulating coke being formed by the adsorption and subsequent condensation of all hydrocarbons (oxygenated and non-oxygenated ones) preferably at low temperatures, whereas filamentous coke is formed when the concentrations of CO and light hydrocarbons in the volatile stream are increased at 800 °C.This work was carried out with the financial support of the grants RTI2018–101678-B-I00, RTI2018–098283-J-I00 and PID2019–107357RB-I00 funded by MCIN/AEI/ 10.13039/501100011033 and “ERDF, a way of making Europe”, and the grant IT1645–22 funded by the Basque Government. Moreover, this project has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No. 823745

Activity and stability of different Fe loaded primary catalysts for tar elimination

[EN] The performance of olivine, dolomite and gamma-alumina primary catalysts was evaluated in the continuous tar elimination process in which toluene was selected as the biomass gasification tar model compound. Iron was incorporated into these catalysts in order to improve their catalytic activity. All the experiments were performed in a continuous flow fluidized bed micro-reactor, with a steam/toluene ratio of 4 and a space velocity (GHSV) of 820 h(-1), which corresponds to a catalyst amount of 3.8 cm(3). The effect of temperature was studied using olivine in the 800-900 degrees C range, which allowed concluding that 850 degrees C was the best temperature for tar removal. The fresh and deactivated catalysts were characterized by N-2 adsorption-desorption, X-ray fluorescence (XRF), X-ray diffraction (XRD) and temperature-programmed oxidation (TPO). Tar conversion efficiency was assessed by means of carbon conversion, H-2 yield (based on the maximum allowed by stoichiometry), gas composition and product yields, with Fe/Al2O3 leading to the highest conversion (87.6 %) and H-2 yield (38 %). Likewise, Fe/Al2O3 also provided the highest stability, as it allowed operating for long periods with high conversion values (85.9 % after 35 min on stream), although it underwent severe deactivation. The analysis of the spent catalysts revealed that deactivation occurred mainly by coke deposition on the catalyst surface and iron phase oxidation, with Fe/olivine and Fe/dolomite leading to the faster deactivation due to their poorer metal dispersion related to their reduced surface area. The TPO profiles showed that the coke deposited on the three catalysts was amorphous with a very small contribution of highly structured carbon.This work was carried out with the financial support of the grants RTI2018-098283-J-I00 and PID2019−107357RB-I00 funded by MCIN/AEI/ 10.13039/501100011033 and by “ERDF A way of making Europe” and the grants IT1218−19 and KK-2020/00107 funded by the Basque Government. Moreover, this project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 823745