Co-pyrolysis Of Sawdust Research Articles

Valorizing polymeric wastes and biomass through optimized co-pyrolysis for upgraded pyrolysis oil: A study on TG-FTIR and fixed bed reactor

The co-pyrolysis of biomass and polymeric wastes offers a promising approach for waste reduction and valuable product recovery while decreasing fossil fuel dependence. This study aimed to investigate the synergistic effects of blending waste tire (WT) or polystyrene (PS) with sawdust (SD) at varying effective hydrogen/carbon ratio (H/Ceff) on liquid product distribution. Thermal degradation behavior was analyzed using TGA-FTIR, followed by fixed-bed reactor pyrolysis experiments at different temperatures. The devolatilization of SD primarily occurred between 185 and 390°C, while WT and PS decomposed between 250 and 500°C and 350–460°C, respectively. Results showed that SD addition to WT accelerated degradation at lower temperatures. Optimal H/Ceff ratios were 0.42 for WT/SD and 0.64 for PS/SD blends at 500°C, maximizing valued hydrocarbons, reducing pollutants, and yielding the highest liquid fraction. TGA-FTIR analysis revealed the presence of various functional groups, including C-H, CC, CO2, and O-H. The pyrolytic oil showed improved stability with significantly fewer undesired compounds. This research provides theoretical and practical insights into the control and application potential as well as the limitations of high-value energy products derived from the co-pyrolysis of SD, WT, and PS.

Biochar from co-pyrolysis of biological sludge and woody waste followed by chemical and thermal activation: end-of-waste procedure for sludge management and biochar sorption efficiency for anionic and cationic dyes

Nine biochars were produced by co-pyrolysis of sawdust and biological sludge following the “design of experiment” approach. Two kinds of sludge (both deriving from the treatment of mixed industrial-municipal wastewater) and two types of woody waste were selected as categorical predicting variables, while contact time, pyrolysis temperature, and sludge percentage were used as quantitative variables. Biochars were analysed for their product characteristics and environmental compatibility based on the European Standards (EN 12915–1:2009) for materials intended for water treatment (i.e. ash content, water leachable polycyclic aromatic hydrocarbons (PAHs) and elements), as well as for specific surface area (SSA), using them as response variables of a multivariate partial least square multiple regression, whose results provided interesting insights on the relationships between pyrolysis conditions and biochar characteristics. Biochars produced with sludge and/or providing the highest SSA values (258–370 m2 g−1) were selected to undergo a sustainable chemical treatment using a by-product of the gasification of woody biomass, complying in all cases with European Standards and achieving therefore the end-of-waste status for sewage sludge. The biochar deriving from the highest percentage of sludge (30% by weight) and with the highest SSA (390 m2 g−1) was thermally activated achieving SSA of 460 m2 g−1 and then tested for the sorption of direct yellow 50 and methylene blue in ultrapure water and real wastewater, compared to a commercial activated carbon (AC). The biochar showed Langmuir sorption maxima (Qm) 2–9 times lower than AC, thus highlighting promising sorption performances. Qm for methylene blue in wastewater (28 mg‧g−1) was confirmed by column breakthrough experiments.

Quantification of degree of interactions during co-pyrolysis of nine typical carbonaceous wastes

Organic municipal waste is a mixture of carbonaceous feedstock and cross-interaction of volatiles in their co-pyrolysis has been well documented, but quantifying their extent of interactions in co-pyrolysis is difficult. In this study, the ratio of char yield from co-pyrolysis to calculated average of pyrolysis of single feedstock was used as an indicator to probe the interaction in co-pyrolysis of every two typical carbonaceous wastes (sawdust, rice, spinach, chicken manure, office paper, corrugated paper, plastic bottles/films, fiber towel) at 550 °C. The results indicated that the co-pyrolysis of sawdust and corrugated paper had the highest degree of interaction (0.44). Sawdust and rice with ash-rich feedstock (spinach, chicken manure and office paper) resulted in dominance of gasification reactions to reduce char production in co-pyrolysis process. In comparison, the organics from the degradation of spinach and corrugated/office paper could react with the derivatives (mostly radicals) of plastic bottle (PET), plastic film (PE) or fiber towel (polyesters) via secondary condensation to generate more char. The chicken manure with high ash content hardly forms char of enhanced yield during its co-pyrolysis with other feedstocks. The enhancing char yield through secondary condensation generally resulted in additional oxygen-containing deposit on char and reduced thermal stability, which was the opposite to the formation of char with dominance of gasification. Co-pyrolysis of varied feedstock also led to change of morphologies of char via filling mechanism or formation of organics.

Adsorptive removal of ciprofloxacin and sulfamethoxazole from aqueous matrices using sawdust and plastic waste-derived biochar: A sustainable fight against antibiotic resistance

We produced carbon-negative biochar from the pyrolysis of sawdust biomass alone (SB) and from the co-pyrolysis of sawdust and plastic waste (SPB). The co-pyrolysis approach in this study was driven by several hypothetical factors, such as increased porosity, surface chemistry, stability, as well as waste management. We applied pyrolyzed and co-pyrolyzed biochars for the removal of ciprofloxacin (CFX) and sulfamethoxazole (SMX). Due to its more alkaline and amorphous nature, SB showed better removal efficiencies compared to SPB. The maximum removals of CFX and SMX with SB were observed as ∼95% and >95%, respectively whereas with SPB were 58.8%, and 34.9%, respectively. The primary mechanisms involved in the adsorption process were H-bonding, electrostatic and π–π electron donor–acceptor interactions. Homogenously and heterogeneously driven adsorption of both antibiotics followed the pseudo-second-order kinetic model, implying electron sharing/transfer (chemisorption) mediated adsorption. The work is highly pertinent in the context of emerging concerns related to drivers that promote antimicrobial resistance.

Techno-economic analysis of sawdust and rice husk co-pyrolysis for bio-oil production

A techno-economic analysis of bio-oil production from co-pyrolysis of sawdust and rice husk blend was performed to assess the feasibility of scaling up the plant capacities. The analysis was conducted at plant capacities of 0.1 kg/h, 100 kg/h and 1000 kg/h in USD currency. Technology evaluation was based on an optimum bio-oil yield of 51.9 % and a blending ratio of sawdust to rice husk 50:50 using a fluidized bed reactor. Sensitivity analysis showed that operating labour costs, nitrogen costs and feedstock costs have a significant impact on the unit production cost of bio-oil. A plant capacity of 1000 kg/h appears to be more economical for bio-oil production at a nominal unit production cost of 0.052 USD/kg.

Oxygen-doped biochar for the activation of ferrate for the highly efficient degradation of sulfadiazine with a distinct pathway

Oxygen-containing functional groups in functionalized biochar (BC) play an important role in its environmental applications. Herein, we introduced oxygen atoms into BC by copyrolysis of sawdust and magnesium carbonate basic pentahydrate (MgCO3)4·Mg(OH)2·5 H2O for the preparation of O-enriched porous BC (OPBC). OPBC800 (OPBC pyrolyzed at 800 °C) exhibited ultrahigh activity to activate ferrate (K2FeO4) for the oxidation of sulfadiazine (SDZ, 100% removal of SDZ in 2 min at pH = 5). We found that SDZ molecules can be rapidly adsorbed by the hierarchical porous structure of OPBC and were expediently oxidized by in situ generated Fe(IV) and Fe(V) active species on the surface of OPBC. The degradation mechanism of SDZ involved is quite different from the well-confirmed mechanism in which only active species in the solution play a role. Electrochemical impedance spectroscopy showed that O-doping in OPBC improved the electron-donating ability and expedited the electron transfer to ferrate, thus enhancing the catalytic activity of OPBC. This provides a new functionalization method for BC and provides more information about the activation of ferrate.

Investigation on the co-pyrolysis of municipal solid waste and sawdust: pyrolysis behaviors, kinetics, and thermodynamic analysis

ABSTRACT This paper aimed to disclose the interaction during the co-pyrolysis of sawdust (Wood) and municipal solid waste (MSW) using a thermogravimetric analyzer at the heating rates of 10, 30, and 50 °C/min. The results of thermogravimetric analysis (TGA) indicated that Wood enhanced the depolymerization reaction of plastics in MSW, while MSW could reduce the thermal decomposition temperature of lignocellulosic substances in Wood. In addition, the devolatilization indexes (Di) for the blended samples were approximately 3 times that of Wood, and the maximum of which was −2.5729 × 10−6 %·min−1·K−3 (in WM11), implying that co-pyrolysis was conducive to the release of volatile matter. Moreover, the apparent activation energy (Eα) was calculated by the Kissinger–Akahira–Sunose (KAS) and Flynn-–Wall–Ozawa (FWO) methods. When the mass ratio of MSW to Wood was 1:1, the value of the average activation energy (Eave) was optimal, which was 191.37 kJ/mol. Additionally, the experimental Eave of WM11 was 15.15 kJ/mol lower than the theoretical. Furthermore, thermodynamic parameters (ΔH, ΔG, and ΔS) were calculated, and the results verified that co-pyrolysis was a feasible and advantageous way to convert waste into energy.

Co-pyrolysis of cellulose/lignin and sawdust: Influence of secondary condensation of the volatiles on characteristics of biochar

The major compounds of cellulose and lignin in biomass could have varied contributions on distribution and properties of pyrolysis products by generating the volatiles of different structures via pyrolysis. In this paper, the co-pyrolysis of cellulose or lignin with sawdust were investigated, aiming to probe the impacts of volatiles from lignin or cellulose pyrolysis on evolution of products. The results indicated that the interactions between volatiles from cellulose or lignin with that of sawdust did exist. The co-pyrolysis of sawdust with cellulose tended to promote the bio-oil production, while the co-pyrolysis with lignin enhanced the formation of biochar. The cross-polymerization of light species (i.e. radicals) from cellulose pyrolysis with heavier ones from lignin pyrolysis transformed the precursors of gases into condensable liquid, bio-oil. In comparison, the interaction of heavy species between lignin and those from sawdust produced more carbonaceous solid, biochar. Additionally, the biochar from co-pyrolysis of sawdust with cellulose possessed more oxygen-containing functionalities (i.e. CO), higher oxygen content, while lower thermal stability, while that from co-pyrolysis with lignin was opposite. The in situ Diffuse Reflection Infrared Fourier Transform Spectra (DRIFTS) analysis suggested that the volatiles from cellulose reacted with that from sawdust formed more aliphatic structures.

Towards Understanding the Mechanism of Heavy Metals Immobilization in Biochar Derived from Co-pyrolysis of Sawdust and Sewage Sludge.

Biochar was prepared by mixing sewage sludge with sawdust via a co-pyrolysis with different mixture ratios and temperatures. The results showed that the sawdust addition resulted in a lower yield of biochar with higher C content. The total concentrations of Pb and Cd in biochar were reduced. Besides, pyrolysis can transform the potentially toxic Pb and Cd to stable fractions. However the sawdust addition had slight influence on the chemical forms of Pb and Cd in the biochar. The biochar with 50% sawdust at 600°C exhibited a remarkable reduction of the leachable metal concentrations. The possible transformation mechanisms of Pb and Cd were inferred as the formation of aluminum and silicon-containing minerals. These results provide insights into the influence of sawdust addition on the characteristics of biochar and the possible Pb and Cd immobilization mechanisms during co-pyrolysis process.

Improvement of bio-crude oil properties via co-pyrolysis of pine sawdust and waste polystyrene foam

Conversion technology of solid biomass to liquid fuel, named bio-crude oil, has been researched widely for the production of renewable energy to replace fossil fuel oil. As the result of many admirable researches, fast pyrolysis technology for bio-crude oil production is close to commercialization. However, bio-crude oil has unsatisfactory properties compared to general petroleum oil, for instance, low heating value, high water content, and high viscosity. In this study, pine sawdust (SD) biomass was co-pyrolyzed with waste polystyrene foam (WPSF), which was expected to improve the bio-crude oil quality due to high heating value and non-oxygen composition of polystyrene. The co-pyrolysis experiment was conducted in a bubbling fluidized bed reactor under the following conditions: temperature of 500 °C which was chosen based on the results from thermogravimetric analysis of SD and WPSF, nitrogen flow rate of 20–25 L/min., and feeding rate of 200 g/hr. Various mixing ratios of SD/WPSF by weight percentage were tested as follows: 100/0, 95/5, 90/10, 85/15, 80/20, 75/25, 70/30, 60/40, 50/50, 25/75, 0/100. Experimental results showed that in case of only SD feeding the bio-crude oil yield and higher heating value (HHV) were 48.83 wt% and 17.81 MJ/kg respectively. By contrast, oil yield and HHV in case of 25% SD with 75% WPSF mixture were 63.31 wt% and 39.65 MJ/kg respectively. Additional analysis showed that water content, and acetic acid concentration of bio-crude oil from co-pyrolysis of SD/WPSF mixture were decreased almost proportionally with the increasing WPSF ratio. Furthermore, measured values of water content, and acetic acid concentration were lower than the calculated values by linear interpolation, which means that the synergistic effect between SD and WPSF was achieved during the co-pyrolysis. In conclusion, co-pyrolysis of SD and WPSF was found as a promising solution to improve bio-crude oil quality. With this technology, the industrial growth of bio-crude oil area is expected as well as waste plastic.

XAS combined with TG–DTG study on synergic effect on sulfur transformation during co-pyrolysis of sawdust and lignite

The synergic effect of sawdust (SD) and a lignite can be observed by analyzing their co-pyrolysis behavior. The co-pyrolysis behavior of SD and lignite mixtures was investigated by thermo-gravimetric analysis, and their sulfur transformation was measured by X-ray absorption spectroscopy (XAS). The pyrolysis process can be divided into three stages for SD and lignite, while four their mixtures. The experimental mass loss of SD and lignite mixture during co-pyrolysis is higher than its theoretically calculated mass loss, especially at the mixing ratio of 1:1. This indicates that synergy occurs during SD and lignite co-pyrolysis process. XAS spectra of sulfur show that SD can promote FeS to decompose before 900 °C during co-pyrolysis, as the peak of FeS decreases in the mixture’s char. However, the experimental sulfur removal of mixtures is lower than the theoretically calculated one. This indicates that synergic effect has no effect on sulfur removal, which is very corresponding to more thiophenes gathering in the mixture’s char, because the peak of thiophenes is very steep for the mixture after pyrolysis. And other sulfurs transformation in the mixture is very similar to that of CF coal. For CF coal and its mixture, sulfate peak increases obviously after pyrolysis, which is mostly caused by absorbing SO2 of alkaline minerals during pyrolysis. This also suggests SD cannot prevent sulfate from forming during co-pyrolysis. Therefore, SD can be added to promote high-pyrite coal to increase sulfur removal, since the decomposition of FeS needs higher temperatures.

Converting spent battery anode waste into a porous biocomposite with high Pb(II) ion capture capacity from solution

Abstract Taking advantage of the low-cost carbon and manganese sources of the spent battery anode waste (SB), porous biocomposites were synthesized by co-pyrolyzing of SB with sawdust. Synthesis method was optimized, and potential biocomposite application in the aspect of Pb(II) removal in the wastewater was investigated and the related possible mechanism of Pb(II) removal was discussed. Composite derived at 750 °C with 10% SB loading amount had high Pb(II) adsorption capacity with negligible influence of ion strength. The maximum Pb(II) adsorption capacity was around 183.82 mg/g at 298 K and pH 4, and the increase of the temperature favored Pb(II) adsorption. Pb(II) adsorption behavior fitted the intraparticle diffusion model and Redlich-Pearson model. Pb(II) removal was governed by precipitation, complexation and Cπ−Pb(II) bond interaction combined processes. Co-pyrolysis of sawdust with SB not only explores an approach for the SB utilization but also provides an excellent biocomposite for solution Pb(II) ion adsorptive removal.

Effect of char on co-pyrolysis of biomass and coal in a free fall reactor

Fast pyrolysis and co-pyrolysis of pine sawdust (SD) and sub-bituminous coal (SB) were carried out in a free fall reactor. There is a gas–solid separator at the bottom of the reactor, where a controlled re-contact of the primary volatiles with the nascent char could be achieved. The experiments of the individual fuels with the volatiles–char re-contact resulted in increased tar yield and decreased the light hydrocarbon gas concentrations compared with that without the volatiles–char re-contact. During the co-pyrolysis of SD and SB, synergies were observed to have produced more tar at different biomass blending ratios (BR). Particularly, the re-contact of the volatiles–char effectively enhanced tar generation and suppressed water formation. The volatiles–char interactions promoted the tar generation mainly at the char bed temperature range from 600°C to 700°C. At the optimum condition with the BR of 0.50 and char bed temperature of 700°C, the tar yield increased up to 28.7%. The co-pyrolysis and volatiles–char interactions favored the acidic components generation in the liquid products. Especially, the volatiles–char re-contact during co-pyrolysis improved the quality of tar by decreasing its asphaltene content.

Bio-oil upgraded by catalytic co-pyrolysis of sawdust with tyre

We have investigated the improvement in the quality of bio-oils by catalytic co-pyrolysis of sawdust and tyre mixture in an integrated reactor. The vapours from co-pyrolysis are allowed to pass through a desulfurising layer composed of zinc oxide and then through the catalytic layer consisting of silver (Ag), palladium (Pd), molybdenum (Mo), or vanadium (V) supported over SBA-15 or HZSM-5. The bio-oils produced by the condensation of vapours are systematically analysed using an elemental analyser, calorimeter, gel permeation chromatograph, densimeter, viscometer, and thermal analyser. Results indicate that the quality of bio-oils can be effectively improved by using Ag/SBA-15 and Pd/SBA-15. The typical bio-oil (SSS40) produced by co-pyrolysis of the mixture containing 40 wt.% sawdust and 60 wt.% tyre with Ag/SBA-15 catalyst have properties similar to that of the diesel fuel no. 0 #. On the other hand, the molecular weight distribution of the upgraded bio-oils obtained from the mixture of 40 wt.% saw dust and 60 wt.% waste tyre with Ag/HZSM-5 as catalyst is close to that of commercial diesel fuel no. 0#. Based on the results, we have also proposed the kinetics associated with the combustion of typical upgraded bio-oil.

Characteristics of Gases From Co-Pyrolysis of Sawdust and Tires

The composition and characteristics of permanent gases that evolve during co-pyrolysis of sawdust and waste tires were observed. Gas composition was determined by gas chromatography, whereas gas characteristics were studied by pyrolysis–Fourier transform infrared (Py-FTIR) spectroscopy. Results show that as co-pyrolysis temperature and the proportion of sawdust in the mixture of biomass and waste tires increase, the gas yield increases, but the relationship between the addition of sawdust and gas yield is nonlinear. A synthetic effect exists among the co-pyrolysis gases. When the mass ratio of sawdust to tires is 1:2, and pyrolysis temperature is 600°C at a flow rate of 90 ml min−1, gas yield reaches 30.3 wt%. The mass fraction accounted for by ignited gases (such as CO, H2, CH4, C3H8, C3H6, and C2H4) is nearly 46% with a gross calorific value (GCV) of 17.9 MJ Nm−3, indicating that the gases may act as fuel gas. As a desulfurizer, ZnO removes 92% of H2S in the gaseous products. The content of H2S is below 10 × 10−9 g g−1 when ZnO is used during co-pyrolysis. Py-FTIR analysis shows that gases containing saturated C–H bonds (such as CH4 and C3H8) evolve first, followed by CO2, CO, and water vapor, and finally, vinyl-containing gases such as C3H6. It confirms that gases produced by co-pyrolysis of biomass and tires are completely utilized as resources while they are disposed. This has a great significance for sustainable supply of energy.

The pyrolysis of sawdust and polyethylene in TG and U-shape tube reactor

The co-pyrolysis of sawdust and polyethylene was carried out in a TG-DTG system and a U-shape tube reactor. This research was focused on the interaction between sawdust and polyethylene during the pyrolysis process. The results showed that the interaction between the sawdust particles and polyethylene particles could be ignored during the devolatile process, but there was interaction among the volatile components in the co-pyrolysis process.