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•Pyrolysis of biomass to produce pyrolysis gas can be used in various areas, such as gas fuels.•The individual gas components of the pyrolysis gas are mostly environmentally ...friendly.•Most biomass feedstocks used for pyrolysis are carbon-cycle compliant and recyclable.•Most of the gases in the PG have a high calorific value and can be used for product upgrading.
Biomass energy has become the fourth largest energy source following coal, oil, and natural gas due to its abundantly available sources. At present, pyrolysis oil and biochar are the main products of biomass pyrolysis for applications. Despite this, biomass products still have an untapped potential that deserves further exploration. Research on biomass pyrolysis gas has progressed gradually and is reaching a commercial level through deeper research. It is possible to purify and decoke pyrolysis gas into different gaseous products according to demand, and its components can also be separated and extracted for other purposes. Therefore, biomass pyrolysis gas has a great deal of potential for development. This paper reviews the mechanism of biomass transformation into pyrolysis gas, equipment, the influence of process parameters, analysis methods, potential applications of pyrolysis gas, and ideas for future pyrolysis gas product upgrading.
This study represents a review of waste tires pyrolysis for energy and material recovery from the optimization perspective, including 1) underlying principles of waste tires pyrolysis, 2) pyrolysis ...conditions optimization, 3) optimized pyrolysis processes and 4) future optimization development directions. The property analysis of waste tires and the summary of pyrolysis mechanism and products show the great potential of waste tires pyrolysis to support circular economy and sustainable development. Waste tires pyrolysis convert this solid waste into potential substitutes for energy and chemical commodities (pyrolysis oil, gas and carbon black). The pyrolysis conditions for optimizing product distribution mainly include temperature, time, pressure, particle size, heating rate and tire type. The occurrence of secondary reactions is very sensitive to these pyrolysis conditions, which is the essence of product distribution optimization. Various optimized pyrolysis processes are developed by changing the pyrolysis conditions. These optimization processes enhance the control of reaction process and product distribution, optimizing pyrolysis product yield or quality. The integrated system including pretreatment, pyrolysis and products refining with the quantitative economic and environmental impact analysis is the main development direction of waste tires pyrolysis in the future. The review aims to bring new opportunities for the optimization and future development of waste tires pyrolysis.
•Waste tires pyrolysis is reviewed from optimization perspective.•Tires pyrolysis has great potential to obtain substitutes for energy and chemicals.•Secondary reaction is the essence of product distribution optimization.•Optimization processes enhance selectivity towards high-value products.•There is a lack of economic and environmental impact analysis of tires pyrolysis.
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
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.
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•Biomass pyrolysis has been classified based on recent advancements.•The merits and demerits of each approach are highlighted.•Suitability of each approach for green hydrogen ...production is discussed.•Biomass pyrolysis is a sustainable and effective approach for H2 production.
Biomass pyrolysis has recently gained increasing attention as a thermochemical conversion process for obtaining value-added products, thanks to the development of cutting-edge, innovative and cost-effective pyrolysis processes. Over time, new and novel pyrolysis techniques have emerged, and these processes can be tuned to maximize the production of high-quality hydrogen. This review examines recent advancements in biomass pyrolysis by classifying them into conventional, advanced and emerging approaches. A comprehensive overview on the recent advancements in biomass pyrolysis, highlighting the current status for industrial applications is presented. Further, the impact of each technique under different approaches on conversion of biomass for hydrogen production is evaluated. Techniques, such as inline catalytic pyrolysis, microwave pyrolysis, etc., can be employed for the sustainable production of hydrogen. Finally, the techno-economic analysis is presented to understand the viability of pyrolysis at large scale. The outlook highlights discernments into future directions, aimed to overcome the current shortcomings.
•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.
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.
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.
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•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.
Pyrolysis is one of the thermochemical technologies for converting biomass into energy and chemical products consisting of liquid bio-oil, solid biochar, and pyrolytic gas. Depending on the heating ...rate and residence time, biomass pyrolysis can be divided into three main categories slow (conventional), fast and flash pyrolysis mainly aiming at maximising either the bio-oil or biochar yields. Synthesis gas or hydrogen-rich gas can also be the target of biomass pyrolysis. Maximised gas rates can be achieved through the catalytic pyrolysis process, which is now increasingly being developed. Biomass pyrolysis generally follows a three-step mechanism comprising of dehydration, primary and secondary reactions. Dehydrogenation, depolymerisation, and fragmentation are the main competitive reactions during the primary decomposition of biomass. A number of parameters affect the biomass pyrolysis process, yields and properties of products. These include the biomass type, biomass pretreatment (physical, chemical, and biological), reaction atmosphere, temperature, heating rate and vapour residence time. This manuscript gives a general summary of the properties of the pyrolytic products and their analysis methods. Also provided are a review of the parameters that affect biomass pyrolysis and a summary of the state of industrial pyrolysis technologies.
