Co-pyrolysis Behavior Research Articles

Microwave-assisted fast co-pyrolysis behaviors and products between microalgae and polyvinyl chloride

Microwave-assisted fast co-pyrolysis of microalgae (MA) and polyvinyl chloride (PVC) was investigated. The pyrolysis profiles, yields of three-phase, the chemical composition of liquid and the ultimate analyses of solid residues were studied. When the power increased from 800 W to 1000 W, the bio-oil yields increased significantly while the proportion of aromatics and the heating value of oil and char decreased. A remarkable synergistic effect between MA and PVC was achieved in terms of oil yield when MA to PVC ratios were 5:5 and 3:7 at 800 W and 5:5 at 1000 W, respectively. With the increase of PVC, the content of nitrogenous and oxygenous organic matter in oil decreased from 29.65% to 0.38% at 800 W. The yield of solid decreased, the HHV increased and the values of H/C had a wave change. According to the quantity and quality of liquid and solid, 30% percentage of PVC was the suitable ratio.

Co-pyrolysis behavior of microalgae biomass and low-quality coal: Products distributions, char-surface morphology, and synergistic effects

In this work, the distributions and releasing properties of the primary volatile products during co-pyrolysis of low-rank coal and green algae (GA) has been studied using fixed-bed reactor with online mass spectrometry. Surface morphology of the char was described quantitatively by SEM combined with fractal theory. Different forms of synergistic effects existed from both the yields of products and composition of the main gaseous products. Positive synergistic effects from tar yield were observed under 25% of GA from 600 to 850 °C, indicating GA promoted the formation of tar. Opposite synergistic effects on the content of H2 and CO were gained when the mass ratio of GA was 50%. The fractal dimensions of co-pyrolysis char were less than the calculated values except under 650 °C, which meant the GA promoted the homogeneity of char surface. This work could provide essential data for proper operation parameters selecting for co-pyrolysis.

Investigation into the Interactions during Staged Thermal Co-conversion of Kraft Lignin and Lignite

The objective of this study is to investigate the interactions during co-pyrolysis of kraft lignin/lignite and subsequent gasification of co-pyrolysis-formed char. The co-pyrolysis behavior of kraft lignin and lignite was conducted in analytical pyrolysis–gas chromatography/mass spectrometry (Py–GC/MS) and thermogravimetric analysis (TGA). Then, the CO2 gasification reactivity of pyrolysis-formed char was also examined in TGA. The experimental results showed that synergy was observed during co-pyrolysis of kraft lignin and lignite, resulting in promoting the formation of several lignin-derived compounds, such as 2,6-dimethylphenol, trans-isoeugenol, anisole, vanillin, and guaiacylacetone. The CO2 gasification reactivity of lignite-derived chars was also obviously promoted as a result of the addition of lignin. The optimal proportion of kraft lignin in the blend may be 30% according to the experimental results from both pyrolysis and gasification. The synergy during co-conversion of kraft lignin and lignit...

Parametric study and global sensitivity analysis for co-pyrolysis of rape straw and waste tire via variance-based decomposition

In present study, co-pyrolysis behavior of rape straw, waste tire and their various blends were investigated. TG-FTIR indicated that co-pyrolysis was characterized by a four-step reaction, and H2O, CH, OH, CO2 and CO groups were the main products evolved during the process. Additionally, using BBD-based experimental results, best-fit multiple regression models with high R2-pred values (94.10% for mass loss and 95.37% for reaction heat), which correlated explanatory variables with the responses, were presented. The derived models were analyzed by ANOVA at 95% confidence interval, F-test, lack-of-fit test and residues normal probability plots implied the models described well the experimental data. Finally, the model uncertainties as well as the interactive effect of these parameters were studied, the total-, first- and second-order sensitivity indices of operating factors were proposed using Sobol’ variance decomposition. To the authors’ knowledge, this is the first time global parameter sensitivity analysis has been performed in (co-)pyrolysis literature.

Co-pyrolysis behavior of fermentation residues with woody sawdust by thermogravimetric analysis and a vacuum reactor

This study aimed at cost-effective utilization of fermentation residues (FR) from biogas project for bio-energy via co-pyrolysis of FR and woody sawdust (WS). In this study, a vacuum reactor was used to study the pyrolysis behaviors of individual and blend samples of FR and WS. Obvious synergistic effects were observed, resulting in a lower char yield but a higher gas yield. The presence of woody sawdust promoted the devolatilization of FR, and improved the syngas (H2 and CO) content in the gaseous products. Compared to those of the char from pyrolysis of individual feedstock, co-pyrolysis of FR and WS in the vacuum reactor promoted the cracking reactions of large aromatic rings, enlarged the surface area and reduced the oxygenated groups of the resulted char.

3-3-3 セルロース－ポリプロピレン混合物の共熱分解挙動

3-3-3 セルロース－ポリプロピレン混合物の共熱分解挙動

Characterization and Kinetics for Co-Pyrolysis of Zhundong Lignite and Pine Sawdust in a Micro Fluidized Bed

Co-pyrolysis behaviors of Zhundong lignite and pine sawdust under isothermal conditions were investigated with a focus on the gas releasing characteristics using a micro fluidized bed reactor. The kinetic parameters were deduced by measuring time-dependent changes in the composition of evolved gases from the pyrolysis reactions, employing the universal integral method. The gas release intensity and conversion rate of pine sawdust were quite different from those of Zhundong lignite because of the difference in chemical structure and element content. The effect of blending ratio on the degree of conversion varied significantly for different gas components; H2, CO, and CH4 conversion became quicker with an increasing biomass ratio, while the variation of CO2 was not obvious. The generally used mechanistic models for gas–solid reactions were examined as ways to interpret the experimental data, and reaction kinetics was deduced with respect to the formation of an individual gas component. The obtained activati...

Study on Gas Products Distributions During Fast Co-pyrolysis of Paulownia Wood and PET at High Temperature

Abstract The fast co-pyrolysis behavior of Paulownia wood (PAW) and Polyethylene terephthalate (PET) was studied via a drop tube fixed-bed reactor under nitrogen atmosphere at temperature ranged from 600 o C to 1000 o C. The discrepancy between experimental and predicted values was presented to investigate the synergistic effects during PAW and PET co-pyrolytic process. The gas yields of all tested blends were increased as the increment of temperature. With PAW ratio in the blends increased, the gas yields were elevated. However, the experimental values of gas yields of the blends were lower than predicted ones indicating that gas products yields were inhibited during co-pyrolysis. The evolution of the gas components containing H 2 , CO, CH 4 , CO 2 and a small quantity of light hydrocarbons (C 2 H 2 , C 2 H 4 and C 2 H 6 ) was investigated at different blending ratios and temperatures.

3-3-3 低温ガス化温度域におけるブナ/ポリエチレン混合物の共熱分解機構

3-3-3 低温ガス化温度域におけるブナ/ポリエチレン混合物の共熱分解機構

Understanding the Co-Pyrolysis Behavior of Indonesian Oil Sands and Corn Straw

In this work, co-pyrolysis of Indonesian oil sands and corn straw was investigated to evaluate the potential synergetic effect. Thermogravimetric analysis was conducted to study the thermal decomposition behaviors of individual and blend feedstocks. Improved pyrolysis characteristics and higher conversion were observed, indicating a remarkable synergetic effect. Moreover, co-pyrolysis experiments were carried out using a fixed bed reactor. The results showed that the co-pyrolysis liquid product yield was increased, while the formation of solid residue was reduced, suggesting a higher conversion. The liquid product characterization by gas chromatography–mass spectroscopy also indicated the significant synergetic effect on the liquid chemical composition. Valuable phenols and alcohols were increased, while unstable aldehydes were decreased, suggesting the chemical interactions between two feedstocks during the co-pyrolysis process. The yield improvement and compositional variations of the co-pyrolysis liqui...

Effect of potassium on thermogravimetric behavior and co-pyrolytic kinetics of wood biomass and low density polyethylene

The effect of potassium on the thermogravimetric behavior and co-pyrolytic kinetics of wood sawdust (WS) and low density polyethylene (LDPE) was investigated using a thermogravimetric analyzer. It was found that the co-pyrolysis behavior of the potassium-treated WS/LDPE mixtures were different from the combination of WS and LDPE, and the maximum weight loss between the experimental and calculated values (ΔW) was up to −24.2%. Potassium has a great influence on the pyrolysis of WS/LDPE mixtures, leading to the decrease of the characteristic decomposition temperature (TP1) and the increase of char yield with increasing potassium content. The simulation of possible structures indicates that [K-cellobiose]+ complexes have different configurations and potassium may facilitate the cracking of the glycosidic linkage and the ring-opening reaction. The kinetic analysis indicated that the co-pyrolysis of the potassium-treated WS/LDPE mixtures could be described by three independent first-order reactions. The increase of the potassium contents in the WS/LDPE mixtures causes an increase trend for E and A values in the first decomposition stage but leads to a decreasing trend in the second stage. Furthermore, the kinetic compensation effect (KCE) has been observed in each decomposition stage for the co-pyrolysis of potassium-treated WS/LDPE mixtures.

Co-Pyrolysis Behaviors of the Cotton Straw/PP Mixtures and Catalysis Hydrodeoxygenation of Co-Pyrolysis Products over Ni-Mo/Al2O3 Catalyst

The doping of PP (polypropylene) with cotton straw improved the bio-oil yield, which showed there was a synergy in the co-pyrolysis of the cotton straw and PP at the range of 380–480 °C. In a fixed-bed reactor, model compounds and co-pyrolysis products were used for reactants of hydrodeoxygenation (HDO) over Ni-Mo/Al2O3. The deoxygenation rate of model compounds decreased over Ni-Mo/Al2O3 in the following order: alcohol > aldehyde > acetic acid > ethyl acetate. The upgraded oil mainly consisted of C11 alkane.

Study on the synergistic co-pyrolysis behaviors of mixed rice husk and two types of seaweed by a combined TG-FTIR technique

An investigation by TG-FTIR analysis was undertaken of the pyrolysis of five samples, three pure samples; Enteromorpha clathrata(EN), Sargassum fusiforme(SA) and rice husk(HU), and two blended 50/50 by weight of Enteromorpha clathrata with rice husk and Sargassum fusiforme with rice husk. The pyrolysis of each pure and each blended sample was divided into four stages; evaporation, depolymerization, devolatilization and carbonization. Differential calorimetry analysis showed that pyrolysis of the rice husk was mainly endothermic, pyrolysis of the blended seaweed and rice husk was exothermic and that the seaweed and rice husk were syergistic coupled during pyrolysis. Comparison of experimental data and theoretical data for calculated DTG curves in the pyrolysis of the blended sample of seaweed and rice husk showed that during the process of the main volatiles being precipitated, the thermal weight-loss rate was improved. The components of the blended sample pyrolised synergistically. The FTIR analysis of volatile gases in the pyrolysis process indicated that oxysulfide and nitrogen gases were released from Enteromorpha clathrata and Sargassum fusiforme, the main components in seaweed being protein and soluble polysaccharides. Due to the blending, some differences were found. The strength of CO and SO precipitation peaks were enhanced in the FTIR spectrum of the blend of EN and HU. However, the precipitated carbonyl peaks were weaked in the FTIR spectrum of the mixture of SA and HU. Kinetic analysis using the Coats-Redfern integral method showed that the pyrolysis activation energy in the blended sample was lower than in the seaweed biomass. Kinetic model functions for the blended samples at high temperature and at low temperature respectively, conformed to the second order rate equation and the Avrami–Erofeev (n=1) equation.

Co-pyrolysis behaviors of energy grass and lignite

A kind of energy grass (giant reedgrass) with high calorific value, high production, low land requirement and low sulfur dioxide emission is introduced into lignite pyrolysis process in this paper. Individual pyrolysis and co-pyrolysis characteristics of energy grass and lignite are investigated by the thermogravimetric analyzer together with mass spectrometer. The individual decomposition indicates that energy grass possesses higher thermochemical reactivity and shorter devolatilization time than lignite. The maximum decomposition rate increases with increasing the heating rate for both energy grass and lignite. The mass spectrometric analysis reveals that the emission of sulfur dioxide from energy grass is much lower than that from lignite. The co-pyrolysis of energy grass and lignite blend is characterized by two-stage thermal degradation processes, which is dominant by energy grass content in the first stage but lignite in the second stage. No obvious interaction between energy grass and lignite is observed during the co-pyrolysis process under the operational conditions investigated in this study. Moreover, the distributed activation energy model is applied to determine the activation energy for the pyrolysis of energy grass, lignite and their blends.

Pyrolysis behaviors and kinetics of refining and chemicals wastewater, lignite and their blends through TGA

Co-pyrolysis behaviors of refining and chemicals wastewater solid (RS) and Huolinhe lignite (HL) were investigated via thermogravimetric analysis (TGA). The thermal degradation process of RS and the blends proceeded in three stages, while two stages for HL. The increased percentage of RS in the blends reduced the characteristic temperature (Ti, Tp, Tf) and residual mass (Mr), while raised the characteristic reaction rate (Rp, Rv) and comprehensive devolatilization parameter (D). The results indicated that there existed some inhibitive interactions between RS and HL. The activation energies were calculated by using the Friedman and Starink method. The activation energy of RS increased first and then decreased with conversion degree, and the variation wasn’t as great as that of the blends and lignite. No matter which conversion degree is, the activation energy decreased with the percentage of RS in the blends increasing. The minimum value was obtained by blending 75wt.% RS.

Co-pyrolysis behaviors and kinetics of sewage sludge and pine sawdust blends under non-isothermal conditions

Mixing of sewage sludge with classical biomass, such as pine sawdust, can compensate the weaknesses of one fuel by another. The pyrolytic characteristics of sewage sludge (SS), pine sawdust (PS), and their blends were investigated under nitrogen atmosphere by dynamic thermogravimetric analysis at three heating rates of 10, 20, and 30 K min−1. Three thermal stages (dehydration, devolatilization, further carbonization) were identified during the pyrolysis of single materials, as well as the blends. Blending of PS with SS can improve the devolatilizaion properties of SS, whereas the initial decomposition temperature increases with the increase in proportion of PS. It has been found that the pyrolytic characteristics of the blends can be estimated from those of parent fuels, suggesting that no significant synergistic effect existed during thermal degradation of PS/SS blends. The dependence of apparent activation energy on conversion obtained by Friedman method and distributed activation energy model (DAEM) revealed that the blends can be considered as multistage process. The results indicated that the DAEM can provide reasonable fits to the experimental data.

Investigation on thermochemical behavior of co-pyrolysis between oil-palm solid wastes and paper sludge.

The pyrolysis characteristics of oil-palm solid wastes, paper sludge and their blends were studied via thermogravimetric analysis. Blends ranging from 10 wt.% to 90 wt.% on dosage ratio were prepared to investigate their co-pyrolysis behavior and kinetics. There was a synergistic interaction at low temperature during co-pyrolysis between oil-palm solid wastes and paper sludge. The synergistic interaction would improve thermochemical pyrolysis reactivity of the blends, which could be attributed to the hydrogenation role and the potential mineral catalytic effects on paper sludge pyrolysis. The value of average activation energy obtained by Starink and Friedmen methods did not gradually decline with the increasing proportion of oil-palm solid wastes in the blends. The lowest average activation energy was achieved when the percentage of oil-palm solid wastes was 70%, which was 152 kJ/mol by Starink and 149 kJ/mol by Friedmen, respectively.

TG/FTIR analysis on co-pyrolysis behavior of PE, PVC and PS

The pyrolysis and co-pyrolysis behaviors of polyethylene (PE), polystyrene (PS) and polyvinyl chloride (PVC) under N2 atmosphere were analyzed by Thermal gravimetric/Fourier transform infrared (TG/FTIR). The volatile products were analyzed to investigate the interaction of the plastic blends during the thermal decomposition process. The TGA results showed that the thermal stability increased followed by PVC, PS and PE. The pyrolysis process of PE was enhanced when mixed with PS. However, PS was postponed when mixed with PVC. As for PE and PVC, mutual block was happened when mixed together. The FTIR results showed that the free radical of the decomposition could combine into a stable compound. When PE mixed with PVC or PS, large amount of unsaturated hydrocarbon groups existed in products while the content of alkynes was decreased. The methyl (CH3) and methylene (CH2) bonds were disappeared while PVC mixed with PE.

Study on co-pyrolysis characteristics of rice straw and Shenfu bituminous coal blends in a fixed bed reactor

Co-pyrolysis behaviors of rice straw and Shenfu bituminous coal were studied in a fixed bed reactor under nitrogen atmosphere. The pyrolysis temperatures were 700°C, 800°C and 900°C, respectively. Six different biomass ratios were used. Gas, tar components were analyzed by a gas chromatograph and a gas chromatography-mass spectrometry respectively. Under co-pyrolysis conditions, the gas volume yields are higher than the calculated values. Co-pyrolysis tar contains more phenolics, less oxygenate compounds than calculated values. The addition of biomass changes the atmosphere during the pyrolysis process and promotes tar decomposition. The SEM results show that the differences between the blended char and their parents char are not significant. The results of char yields and ultimate analysis also show that no significant interactions exist between the two kinds of particles. The changes of gas yield and components are caused by the secondary reactions and tar decomposition.

Co-pyrolysis Behavior of Low-grade Coal and Binder Using High Temperature Solvent Fractionation

The authors have proposed a high temperature solvent fractionation method that can separate coals into several fractions having different molecular weight without destroying coal structure. In this study the method was applied to characterization of low-grade coals and binder during their co-pyrolysis to clarify chemical interaction between them. When a sub-bituminous coal or a slightly-caking coal was co-pyrolyzed with asphalt pitch (ASP), it was found that smaller-molecular weight compounds less than 800 in molecular weight which were abundant in ASP could be added by appearance as can be expected from the calculation assuming no interaction between the coals and ASP. The added smaller-molecular weight compounds contributed to the reduction of viscosity of the pyrolyzing coal. The possibility was also suggested that part of smaller-molecular weight compounds in ASP were converted to heavier compounds whereas some smaller-molecular weight compounds were formed from coals to compensate the loss of such compounds derived from ASP. It was also shown that oxygen existent in the heaviest fraction of the low-grade coals was removed to form H2O and CO2 by chemical interaction with ASP. This interaction was found to contribute to the reduction of shrinkage of low-grade coals during carbonization.