The objective of this study was to elucidate primary and secondary reactions of cellulose pyrolysis, which was accomplished by comparing results from a micro-pyrolyzer coupled to a GC–MS/FID system ...and a 100g/hr bench scale fluidized bed reactor system. The residence time of vapors in the micro-pyrolyzer was only 15–20ms, which precluded significant secondary reactions. The fluidized bed reactor had a vapor residence time of 1–2s, which is similar to full-scale pyrolysis systems and is long enough for secondary reactions to occur. Products from the fluidized bed pyrolyzer reactor were analyzed using a combination of micro-GC, GC–MS/FID, LC–MS and IC techniques. Comparison between the products from the two reactor systems revealed that the oligomerization of leglucosan and decomposition of primary products such as 5-hydroxymethyl furfural, anhydro xylopyranose and 2-furaldehyde were the major secondary reactions occurring in the fluidized bed reactor. This study can be used to build more descriptive pyrolysis models that can predict yield of specific compounds.
•Two main pyrolysis stage of waste bicycle tire can be observed from TG.•The release characteristics of volatiles was consistent with pyrolysis behavior.•FTIR spectrum at different temperature ...indicated two main pyrolysis stages.•Pyrolysis mechanism of waste bicycle tire was free radical mechanism.
Pyrolysis of waste tire is attracting widespread interest recently because of the great potential in waste valorization treatment. In this study, the thermal decomposition behavior, pyrolysis mechanism and products distribution of waste bicycle tire were investigated by means of TG-FTIR and Py-GC/MS. According to the TG results, two main pyrolysis stages of waste bicycle tire were observed, which were considered as the decomposition of rubber (285–531 °C) and further pyrolysis of pyrolytic products (663–847 °C), respectively. The volatiles release characteristics and FTIR spectrum at different temperatures exhibited good consistency with pyrolysis behavior. A detail information of pyrolysis products was analyzed by Py-GC/MS, which mainly include gaseous, alkenes and aromatics. The pyrolysis mechanism of waste bicycle tire was belong to free radical reaction, and the possible further pyrolysis pathway of D-limonene and styrene was also presented. Moreover, the products distribution under different pyrolysis final temperatures and heating rates conditions were summarized. Thus, this study could enhance our understanding on more specific details for the pyrolysis process of waste tire to some extent.
A nanocomposite of alpha-Fe.sub.2O.sub.3/alkalinized C.sub.3N.sub.4 (alpha-Fe.sub.2O.sub.3/A-C.sub.3N.sub.4) electrocatalyst for oxygen reduction reaction (ORR) was synthesized by a simple in situ ...electrostatic adsorption of A-C.sub.3N.sub.4 and iron-based ionic liquid OmimFeCl.sub.4 complexation reaction using sonication treatment followed by pyrolysis process. The as-prepared alpha-Fe.sub.2O.sub.3/A-C.sub.3N.sub.4 nanocomposite can act as a superior electrocatalyst for ORR in terms of excellent ORR activity with onset potential of 0.82 V vs. reversible hydrogen electrodes (RHE), current density of 5.2 mA cm.sup.-2 and outstanding methanol resistance. This cost-effective starting materials and simple preparation method paves the way to large-scale fabrication of low-cost and highly active noble metal-free electrocatalyst and promotes their practical applications in electrochemical power conversion and storage system. Graphical abstract
There has been an enormous amount of research in recent years in the area of thermo-chemical conversion of biomass into bio-fuels (bio-oil, bio-char and bio-gas) through pyrolysis technology due to ...its several socio-economic advantages as well as the fact it is an efficient conversion method compared to other thermo-chemical conversion technologies. However, this technology is not yet fully developed with respect to its commercial applications. In this study, more than two hundred publications are reviewed, discussed and summarized, with the emphasis being placed on the current status of pyrolysis technology and its potential for commercial applications for bio-fuel production. Aspects of pyrolysis technology such as pyrolysis principles, biomass sources and characteristics, types of pyrolysis, pyrolysis reactor design, pyrolysis products and their characteristics and economics of bio-fuel production are presented. It is found from this study that conversion of biomass to bio-fuel has to overcome challenges such as understanding the trade-off between the size of the pyrolysis plant and feedstock, improvement of the reliability of pyrolysis reactors and processes to become viable for commercial applications. Further study is required to achieve a better understanding of the economics of biomass pyrolysis for bio-fuel production, as well as resolving issues related to the capabilities of this technology in practical application.
Turning plastic waste into plastic oil by pyrolysis is one of the promising techniques to eradicate plastic waste pollution and accelerate the circular economy of plastic materials. Plastic waste is ...an attractive pyrolysis feedstock for plastic oil production owing to its favorable chemical properties of proximate analysis, ultimate analysis, and heating value other than its abundant availability. Despite the exponential growth of scientific output from 2015 to 2022, a vast majority of the current review articles cover the pyrolysis of plastic waste into a series of fuels and value-added products, and up-to-date reviews exclusively on plastic oil production from pyrolysis are relatively scarce. In light of this void in the current review articles, this review attempts to provide an up-to-date overview of plastic waste as pyrolysis feedstock for plastic oil production. A particular emphasis is placed on the common types of plastic as primary sources of plastic pollution, the characteristics (proximate analysis, ultimate analysis, hydrogen/carbon ratio, heating value, and degradation temperature) of various plastic wastes and their potential as pyrolysis feedstock, and the pyrolysis systems (reactor type and heating method) and conditions (temperature, heating rate, residence time, pressure, particle size, reaction atmosphere, catalyst and its operation modes, and single and mixed plastic wastes) used in plastic waste pyrolysis for plastic oil production. The characteristics of plastic oil from pyrolysis in terms of physical properties and chemical composition are also outlined and discussed. The major challenges and future prospects for the large-scale production of plastic oil from pyrolysis are also addressed.
Display omitted
•LDPE, HDPE, PP, and PS are more promising than PVC and PET as pyrolysis feedstock.•Low to moderate temperature, heating rate, and residence time favor plastic oil.•Lower pressure, smaller particle size and reactive gas atmosphere favor plastic oil.•Catalysts usually promote better plastic oil quality but do not necessarily yield.•Plastic oil is fit for fossil fuel blending/replacement due to its good properties.
Display omitted
•Reactions of tobacco is studied under inert and oxidative atmosphere.•The role of oxygen on the course of thermal degradation is investigated.•A methodology is proposed to ...distinguish oxidative pyrolysis from oxidation reactions.•The methodology is based on cross-correlation of mass loss, gas analysis and thermicity.
When heated up in oxidative atmospheres, lignocellulosic materials undergo complex series/parallel reactions of pyrolysis and combustion, sometimes leading to homogeneous or heterogeneous ignition. It is therefore challenging to draw a clear border between purely degradative and oxidation reactions. This work is part of a larger investigation on the role of oxygen in the patterns, chemistry, and kinetics of tobacco’s thermochemical degradation. The topic is particularly interesting for the design of innovative tobacco products that heat tobacco instead of combusting it, but it is also relevant for thermochemical conversion of all lignocellulosic biomass in general. Experiments of thermochemical degradation of tobacco have been carried out at different heating rates, under inert and oxidative atmospheres, both by Thermogravimetry (TG)/Differential Scanning Calorimetry (DSC) and in a small-scale fixed bed reactor, with contextual analysis of reaction products. In the present work, attention is devoted to the thermal effects and formation of carbon monoxide (CO) and carbon dioxide (CO2). A methodology based on the comparison of mass loss, heat and gas release curves is applied to distinguish between reactions of oxidative pyrolysis and combustion. It is shown that below 300 °C oxidative atmospheres enhance volatiles abstraction, but heterogeneous combustion/ignition of the tobacco only occurs at temperatures above 400 °C. Molecular oxygen present in the gaseous atmosphere around the biomass particles indeed facilitates rupture of the biomass macromolecular structure during heat-up, leading to the release of some volatile components.
The search for an effective, cost-efficient, and selective sorbent for COsub.2 capture technologies has been a focus of research in recent years. Many technologies allow efficient separation of ...COsub.2 from industrial gases; however, most of them (particularly amine absorption) are very energy-intensive processes not only from the point of view of operation but also solvent production. The aim of this study was to determine COsub.2 and CHsub.4 sorption capacity of pyrolyzed spruce wood under a wide range of pressures for application as an effective adsorbent for gas separation technology such as Pressure Swing Adsorption (PSA) or Temperature Swing Adsorption (TSA). The idea behind this study was to reduce the carbon footprint related to the transport and manufacturing of sorbent for the separation unit by replacing it with a material that is the direct product of pyrolysis. The results show that pyrolyzed spruce wood has a considerable sorption capacity and selectivity towards COsub.2 and CHsub.4. Excess sorption capacity reached 1.4 mmol·gsup.−1 for methane and 2.4 mmol·gsup.−1 for carbon dioxide. The calculated absolute sorption capacity was 1.75 mmol·gsup.−1 at 12.6 MPa for methane and 2.7 mmol·gsup.−1 at 4.7 MPa for carbon dioxide. The isotherms follow I type isotherm which is typical for microporous adsorbents.
•Microwave pyrolysis is superior to conventional methods in treating tannery sludge.•Microwave pyrolysis facilitates the reduction of Cr(VI) to Cr(III).•Microwave pyrolysis efficiently removes toxic ...substances from tannery sludge.•Microwave pyrolysis effectively fixes heavy metals in the residues.
The efficient and safe treatment of tannery sludge (TS) are causing significant concern. Pyrolysis stands as a pivotal technology in the realm of sludge treatment, offering the benefits of degrading organic matters within TS while simultaneously transforming the sludge into energy and other valuable substances. In order to develop an effective pyrolysis method with good resource recovery performance, this study employs microwave pyrolysis (MP) and conventional pyrolysis (CP) at temperatures ranging from 300 to 900 °C to investigate the transformation of chromium morphology. The results indicate that TS experienced a weight loss of 43 % during the pyrolysis process, with a combined average activation energy measured at 169.58 kJ/mol. MP, due to its more uniform and efficient heating, resulted in pronounced solid degradation, leading to increased pyrolysis gases. This enhanced the removal of organics at lower temperatures and contributed to the ring opening of aromatic hydrocarbons in the high-temperature segment. MP effectively reduced Cr(VI) to Cr(III) in TS, whereas CP showed relatively ineffective reduction of Cr(VI). Furthermore, metal compounds in TS treated by both MP and CP predominantly existed in the residue as FeCr2O4 and Cr2O3 at high temperatures. This suggests that more Cr(III) was immobilized in the pyrolysis residue. This study revalues the significance of MP as a promising treatment for TS, holding the potential for resource utilization.
Display omitted
•Ablative fast-pyrolysis with fractional condensation validated via 1200 kg bio-oil.•Slurry hydroprocessing enabled bio-oil stabilization.•Stablized bio-oil hydrotreated to high ...quality bio-based intermediate (BioMates)•20 wt% mass yield and 32 wt% carbon yield from straw to BioMates.
Reducing the use of fossil fuels is an ongoing and important effort considering the environmental impact and depletion of fossil-based resources. The combination of ablative fast pyrolysis and hydroprocessing is explored as a pathway allowing bio-based intermediates (BioMates) integration in underlying petroleum refineries. The proposed technology is validated in industrially relevant scale, identifying pros and cons towards its commercialization. Straw from wheat, rye and barley was fed to ablative fast pyrolysis rendering Fast Pyrolysis Bio-Oil (FPBO) as the main product. The FPBO was stabilized via slurry hydroprocessing, rendering a stabilized FPBO (sFPBO) with 49 % reduced oxygen content, 71 % reduced carbonyl content and 49 % reduced Conradson carbon residue. Fixed bed catalytic hydroprocessing of sFPBO resulted in the production of BioMates, a high bio-content product to be co-fed in established refinery units. Compared to the starting biomass, BioMates has 83.6 wt% C content increase, 92.5 wt% O content decrease, 93.0 wt% water content decrease, while the overall technology has 20 wt% conversion yield (32 wt% carbon yield) from biomass to BioMates.
PDF
