Pyrolysis Of Fractions Research Articles

Assessing the influence of biomass origin and fractionation methods on pyrolysis of primary biomass fractions

Pyrolysis has emerged as a highly promising technology for the efficient utilization of organic materials, particularly lignocellulosic materials. This study investigates the behavior and influence of three primary biomass fractions (cellulose, hemicellulose, and lignin) derived from different sources (trees, shrubs, and agricultural residues) on the kinetic of the pyrolysis process. With this objective, different fragmentation methods were employed to isolate the main components of the lignocellulosic biomass, followed by thermogravimetric analysis to examine the pyrolysis process. The activation energy was determined using both, the Friedman differential kinetic models of and the Flynn-Wall-Ozawa integrated method, with the latter being found to be more efficient. The activation energy (Ea) was found to be influenced by several factors, including the fractionation process and the origin of the raw material. For hemicellulose, the Ea was in the range of 200–300 kJ mol−1, while cellulose showed Ea values of about 180–220 kJ mol−1. In contrast, lignin displayed a wider range of Ea variation, with its values being more sensitive to the fractionation method used. Gas samples were collected through adsorption tubes during pyrolysis for analysis of gas stream compositions from different lignocellulosic fractions using gas chromatography/mass spectrometry. Furfural, among other compounds, was predominantly detected in the pyrolysis of hemicellulose fractions, ranging from 6.6 % to 19.3 %.

Evaluation of fossil geomacromolecular sources by the pyrolysis of density fractions of kerogens from Cretaceous and Miocene organic-rich marine shales

Evaluation of fossil geomacromolecular sources by the pyrolysis of density fractions of kerogens from Cretaceous and Miocene organic-rich marine shales

Color characteristics and pyrolysis volatile properties of main colored fractions from the Maillard reaction models of glucose with three amino acids

The effects of hydrosoluble colored fractions generated in the Maillard reaction models on the volatiles of pyrolytic Maillard reaction products was investigated. The hydrosoluble colored fractions obtained by reaction of glucose with glycine (Gly-Glc), proline (Pro-Glc) and phenylalanine (Phe-Glc) respectively at 125 °C were separated using Sephadex LH-20 Gel column. The colored fraction with large molecular weight had a higher contribution to the overall color and more glucose residue structures in main skeleton than that with small molecular weight in the same model. Gel permeation chromatography analysis indicated that these colored fractions had continuous relative molecular weight distribution (1000–80000 Da). Pyrolysis - gas chromatography - mass spectrometry determination (pyrolysis temperature: 160∼900 °C) suggested that furans and pyrroles were the main volatiles of two Gly-Glc fractions after pyrolysis, and the key pyrolysis volatiles of Pro-Glc fraction were furans, pyrroles, pyran, indole and cyclopentenes, which gave a freshly baked bread, nutty, coffee-like and sweet caramel-like odor. Especially phenyl-containing compounds seemed typical indicators of Phe-Glc fraction pyrolysis products, exhibiting a benzene-like, tallowy, sweet, balsamic and floral odor. The hydrosoluble colored fractions produced by different Maillard reactions had different pyrolytic volatile properties and were suitable for the development of bakery food improver with different color and flavor requirements.

CO2 capture and utilization by biocatalytic synthesis of carboxylic acids: a process design study

The search for less energy-intensive processes is pushing toward a diversification of Carbon-Capture and Utilization/Sequestration (CCU/S) pathways. Biocatalytic processes offer sustainable solutions characterized by extremely mild operating conditions. Over the last decade, post-combustion CO2 capture based on enzymatic reactive absorption experienced remarkable growth from the laboratory to the demonstration scale. The present study explores a novel CCU concept based on phenol carboxylation catalyzed by cofactor-free decarboxylases. The design of the CCU process includes CO2 capture by alkaline solvents boosted by carbonic anhydrase followed by bicarbonate fixation via enzymatic phenol carboxylation. Phenols generated from fractional pyrolysis of biomass were assumed as carboxylation substrates. Two process layouts have been developed and modelled, and reliable experimental data and kinetic model supported the computations. Simulated best cases prove to be feasible options for integrating the enzyme cascade with the conventional CO2 absorption/desorption loop and lignocellulose biomass-derived substrates.

Pyrolysis of combustible fractions in excavated waste: Effect of landfill time on pyrolysis characteristics analyzed by TG-FTIR-MS

Excavated waste in landfills contains non-negligible amounts of combustible fractions, whose mining and thermochemical treatment are promising to save land occupation and achieve energy utilization. Considering the possible changes of combustible fractions in the excavated waste during landfill time, this study comprehensively analyzed the impact of landfill time on the thermogravity characteristics, pyrolysis kinetics, products composition, and pyrolysis pathways of excavated waste using TG-FTIR-MS. The findings indicated a positive correlation between landfill time and the remaining mass resulting from pyrolysis. The activation energies for pyrolysis of excavated waste were found to be greater than those of fresh waste. Specifically, the activation energy values increased from 230.49 kJ/mol to 289.11 kJ/mol for polyethylene, from 216.38 kJ/mol to 260.91 kJ/mol for polypropylene, from 219.04 kJ/mol to 240.06 kJ/mol for expanded polystyrene, and from 210.01 kJ/mol to 279.93 kJ/mol for polyethylene terephthalate, respectively. The increment of activation energies indicates an elevated level of difficulty in the pyrolysis reaction. The pyrolysis kinetics of excavated waste were examined by the Kissinger-Akahira-Sunose (KAS), Flynn-Wall-Ozawa (FWO), and Starink methods. It was found that FWO method showed an optimal fitting result (R2 =0.9681–0.9819), while KAS and Starink methods also showed satisfactory fitting performance. The TG-FTIR-MS results revealed that the effect of landfill time on products categories are negligible, but the change in the content of pyrolysis products is more pronounced. This study is hoped to provide fundamental insights into the thermochemical disposal and energy recovery of excavated waste in landfills.

Electric arc pyrolysis of different fractions derived from waste tire pyrolysis oil

The paper reports the experimental results on extraction and characterization of different fractions (light (<180 °C), middle (180–350 °C), and heavy (>350 °C)) derived from pyrolysis oil of waste tires of mining vehicles, followed by their electric arc pyrolysis in order to produce nanosized carbon material. The released gas was found to contain 20.4–37.1 vol% hydrogen, 7.4–24.9 vol% methane, and 24.7–27.9 vol% carbon monoxide. The carbon material obtained was presented by an array of nanosized particles (30–250 nm) with a graphite-like structure and a wide range of specific surface area values (Ssf = 38.8–79.7 m2/g). The content of carbon and sulfur was 98.3–99.1 wt% and 0.1–0.3 wt%, respectively. Transmission electron microscopic analysis of the test samples revealed two types of carbon nanostructures of different morphology: polyhedral graphite and carbon nano-onions. Characteristics of the samples obtained from pyrolysis oil and its fraction with a boiling point exceeding 350 °C were the closest to those of carbon black.

Reviewing the use of zeolites and clay based catalysts for pyrolysis of plastics and oil fractions

Reviewing the use of zeolites and clay based catalysts for pyrolysis of plastics and oil fractions

Evaluating fractional pyrolysis for bio-oil speciation into holocellulose and lignin derived compounds

Fractional pyrolysis of lignocellulosic biomass, by staged thermal treatment, has been assessed as an in-situ speciation method of the bio-oil components that could be highly beneficial for extracting valuable compounds or for their subsequent catalytic upgrading. Wheat straw and pine woodchips were used as representative biomasses. Based on the results of TG analyses in an inert atmosphere, 350 and 700 °C were selected, respectively, as operational temperatures for the fractional pyrolysis. Compared to single-step pyrolysis, fractional thermal treatment of both biomasses led to some reduction of the bio-oil yield but with improved properties due to their lower oxygen content. Sharp differences were observed in the bio-oil composition obtained at the two steps of fractional pyrolysis. GC-MS analyses revealed that most of the compounds detected in the bio-oil obtained at 350 °C were products formed by the decomposition of polysaccharides, such as carboxylic acids, furans, sugars, and light oxygenates. In contrast, the organic liquid phase obtained during the subsequent treatment at 700 °C was rich in aromatic oxygenated compounds, coming from the lignin conversion. The content of oligomeric and heavy species, not detected by GC-MS, was much higher in the bio-oils obtained in the high-temperature step of fractional pyrolysis, denoting that they are largely formed from lignin. Significant changes were also observed in the relative contribution of the deoxygenation pathways during the two steps of fractional pyrolysis. Thus, dehydration was the predominant deoxygenation route during the degradation of the holocellulose biopolymers at the low-temperature step, whereas the decomposition of the lignin-rich solid at the high-temperature treatment proceeded with a significant contribution of decarbonylation and decarboxylation. These results evidence the great potential of lignocellulose fractional pyrolysis to generate bio-oil streams with high speciation of the components, facilitating sharply their further processing and upgrading.

Теплотехнические характеристики процесса пиролиза отработанных шин

A significant annual growth in the number of spent car tires creates a serious environmental problem and calls for the need to continue searching for efficient resource-saving methods of their recycling. There is a growing number of efforts aimed at studying waste tire thermochemical conversion processes, including their pyrolysis to obtain valuable products, including a solid fraction (coke residue), liquid hydrocarbon fraction (pyrolysis oil), and noncondensable gaseous fraction (pyrolysis gas). Commercial and pilot pyrolysis plants and reactors are reviewed. A rotating drum reactor, shaft and screw reactors are the most promising solutions for implementing a continuous process. The development of new resource-saving solutions for the pyrolysis of waste tire requires knowledge of the thermal characteristics of this process, including information on the material and heat flows in the pyrolysis reactor. The composition and thermal properties of waste tire, as well as specific outputs, composition and fuel properties of pyrolysis product material flows, including pyrolysis gas, pyrolysis oil and coke residue, are presented. Information on the pyrolysis plant or reactor heat balance structure is either absent or incomplete. Based on the data available in the literature, the heat balance of a commercial pyrolysis plant equipped with screw reactors characterized by a specific thermal destruction heat of 0.640 MJ/(kg of tires) is drawn up and studied. The numerical analysis results correlate with the data published for the commercial-grade plant. Information on the pyrolysis chamber heat balance structure is correct enough for use in engineering practice. It has been found that the specific heat consumption for the pyrolysis process is 2.269 MJ/(kg of tires). This value can be used in numerically analyzing pyrolysis plants equipped with other designs of pyrolysis reactors.

In situ and Ex situ Catalytic Pyrolysis of Microalgae and Integration With Pyrolytic Fractionation.

Microalgae are attractive feedstocks for biofuel production and are especially suitable for thermochemical conversion due to the presence of thermally labile constituents—lipids, starch and protein. However, the thermal degradation of starch and proteins produces water as well as other O- and N-compounds that are mixed-in with energy-dense lipid pyrolysis products. To produce hydrocarbon-rich products from microalgae biomass, we assessed in situ and ex situ catalytic pyrolysis of a lipid-rich Chlorella sp. in the presence of the HZSM-5 zeolite catalyst over a temperature range of 450–550°C. Results show that product yields and compositions were similar under both in situ and ex situ conditions with benzene, toluene and xylene produced as the primary aromatic products. Yields of aromatics increased with increasing temperature and the highest aromatic yield (36.4% g aromatics/g ash-free microalgae) and selectivity (87% g aromatics/g bio-oil) was obtained at 550°C. Also, at this temperature, oxygenates and nitrogenous compounds were not detected among the liquid products during ex situ catalytic pyrolysis. We also assessed the feasibility of a two-step fractional pyrolysis approach integrated with vapor phase catalytic upgrading. In these experiments, the biomass was first pyrolyzed at 320°C to degrade and volatilize starch, protein and free fatty acids. Then, the residual biomass was pyrolyzed again at 450°C to recover products from triglyceride decomposition. The volatiles from each fraction were passed through an ex situ catalyst bed. Results showed that net product yields from the 2-step process were similar to the single step ex situ catalytic pyrolysis at 450°C indicating that tailored vapor phase upgrading can be applied to allow separate recovery of products from the chemically distinct biomass components—(1) lower calorific value starch and proteins and (2) energy-dense lipids.

OH-Initiated Reactions of para-Coumaryl Alcohol Relevant to the Lignin Pyrolysis. Part III. Kinetics of H-Abstraction by H, OH, and CH3 Radicals

Lignin is the most complex component of biomass, and development of a detailed chemical kinetic model for biomass pyrolysis mainly relies on the understanding of the lignin decomposition kinetics. para-Coumaryl alcohol (p-CMA, HOPh-CH═CH-CH2OH), the focus of our analysis, is the simplest of the lignin monomers (monolignols) containing a typical side-chain double bond and both alkyl- and phenolic-type OH-groups. In parts I and II of our work (Asatryan, R. J. Phys. Chem. A 2019, 123, 2570-2585; Hudzik, J. M. J. Phys. Chem. A 2020, current issue), we created a detailed potential energy surface (PES) and performed a kinetic analysis of chemically activated, unimolecular, and bimolecular reactions pathways for p-CMA + OH. Reaction pathways analyzed include dissociation, intramolecular abstraction, group transfer, and elimination processes. The α- and β-carbon addition reactions generate 1,3- (RA1) and 1,2-diol (RB1) adduct radicals, respectively. Well depths are approximately 29 and 41 kcal/mol below the p-CMA + OH entrance level. Kinetic analysis aides in determining the major pathways for our conventional and fractional pyrolysis experiments. The current paper focuses on the H-abstraction reactions via H, OH, and CH3 light ("pool") radicals from p-CMA. The thermochemical properties of all stable, radical, and transition-state species were determined using the ωB97XD density functional theory (DFT) and higher-level CBS-QB3 composite methods. Barrier heights from the prereaction complexes, for OH-radical abstractions, to the transition states for the propanoid side chain are compared to the model H-abstraction reactions of allyl alcohol (AA) with OH and p-CMA with H and CH3 radicals. The lowest-energy, most stable, p-CMA radical formed is at the C9 allylic position (p-CMA-C9j) with exothermicity of 26.63, 41.32, and 27.34 kcal/mol for H, OH, and CH3, respectively. For OH-radical abstraction at this position, our findings are consistent with corresponding data on AA + OH at 37.44 kcal/mol and similar to that of RB1. A similar stable radical with an exothermicity of 34.95 kcal/mol occurs for the phenol hydroxyl group, generating the p-CMA-O4j radical. H-abstraction pathways are considered in relation to other major pathways previously considered for p-CMA + OH reactions including H-atom shifts, dehydration, and β-scission reactions. Derived rate coefficients for substituted phenols can be utilized in detailed kinetic models for lignin/biomass pyrolysis.

Моделирование и исследование процесса охлаждения твердых продуктов пиролиза отработанных шин

Every year, 1.5 billion tires are produced around the world, and each of them eventually falls into the waste stream. The growing volume of waste tires and limited possibilities for their disposal generate the need to develop methods for recycling them. A review of papers addressing the waste tire recycling problem with the use of proposed mechanical and thermochemical processing methods is presented. It is shown that researchers take interest in pyrolysis as a technology for thermochemical conversion of waste tire to produce valuable products: a solid fraction represented by coke residue (carbon black), a liquid hydrocarbon fraction (pyrolysis oil), and non-condensing gaseous fraction (pyrolysis gas). In a number of published papers, focus is placed on improving the consumer properties of each fraction. Conditions under which the coke residue quality can be improved to the level of activated carbon are, and methods for implementing this are developed. The cooling of solid pyrolysis products can be a limiting factor for the pyrolysis plant operation. Unloading of the coke residue at increased temperatures with outdoor cooling can lead to its burning out. To develop an efficient coke residue cooling heat exchanger, it is necessary to know the physical properties of this substance. A method for determining the thermal conductivity of fine coke residue based on the use of physical and mathematical modeling of the cooling process has been developed and implemented. Experiments on studying the coke residue bed cooling process in air in the temperature range from 500 °C to the ambient temperature were carried out. The time dependences of temperature at several points of the bed layer are obtained. A measuring chamber mathematical model reproducing the experimental conditions is developed. By studying the model, it is possible to determine the coke residue thermal conductivity, which approximates the calculated cooling process temperature curves to those obtained in the experiment with satisfactory accuracy. Based on the analysis of experimental data, two temperature ranges are identified, and a linear dependence of the bed thermal conductivity on the temperature is found in each of them. The coefficients of these functions are determined by minimizing the response function using the Box--Wilson method. The obtained results are used for the development of industrial thermal power engineering facilities.

Sulfur contaminations inhibit depolymerization of Kraft lignin

Softwood Kraft lignin (s-KL) and methanol-fractionated extracted Kraft lignin (ex-KL) samples were thermally depolymerized via fractional (step-wise) pyrolysis at temperatures from 175 °C to 700 °C in an isothermal System for Thermal Diagnostic Studies (STDS) reactor. Major pyrolysis products include guaiacols, vanillins, phenols, syringols, and sulfur-containing compounds. Sulfur-containing compounds, as intrinsic contaminants (both adsorbed and covalently bound to KL matrixes), strongly inhibited the formation of pyrolysis products. The lesser the sulfur content in the KL matrix, the higher the yields of major pyrolysis products. The high yields and early release of tar components from pyrolysis of ex-KL were attributed to the initial pretreatment of s-KL (Soxhlet extraction in methanol) causing a decrease in sulfur content from 3.61% (s-KL) to 2.91% (ex-KL). Mechanistic explanations for the absence of sulfur-containing bio-oil products, inhibitory effect of sulfur-containing compounds, and the relatively high char content in depolymerization of both lignin substrates, are developed.

TGA-FTIR study on the slow pyrolysis of lignin and cellulose-rich fractions derived from imidazolium-based ionic liquid pre-treatment of sugarcane straw

Slow pyrolysis of regenerated cellulose-rich material (RCRM) and recovered lignin produced from imidazolium-based ionic liquid (IL) pre-treatment of sugarcane straw (SCS) was investigated employing a Thermogravimetric Analyser (TGA) instrument coupled with a Fourier-Transform Infrared (FTIR) spectroscopy. 1-ethyl-3-methylimidazolium acetate ([Emim][OAc]) pre-treatment of SCS altered the hydrogen bonds of cellulose and produced amorphous Cellulose II structure in RCRM. FTIR spectroscopic analysis of liquid products showed that the IL pre-treatment increased the production of furans from the pyrolysis of RCRM, because the presence of amorphous Cellulose II in RCRM enhanced the dehydration reaction during pyrolysis. Moreover, the recovered lignin from IL pre-treatment enhanced the production of phenol-rich pyrolysis oil due to the cleavage of β-O-4 ether bonds of lignin during pre-treatment. Scanning electron microscope (SEM) analysis indicated highly porous structure of both RCRM and recovered lignin derived biochars. The kinetic analysis using a hybrid approach (a combination of model-fitting and model-free methods) indicated a reduction in the activation energy for both RCRM and recovered lignin pyrolysis. It is concluded that IL pre-treatment of lignocellulosic biomass followed by low-temperature pyrolysis can be an efficient route for biorefinery production.

Enhanced debromination by Fe particles during the catalytic pyrolysis of non-metallic fractions of printed circuit boards over ZSM-5 and Ni/SiO2-Al2O3 catalyst

A two-stage fixed-bed reactor was used to investigate the catalytic pyrolysis of non-metallic fractions of printed circuit boards (PCBs) over ZSM-5 and Ni/SiO2-Al2O3 (Ni/SA) catalysts. The addition of Fe particles to the catalyst was evaluated for bromine removal from the pyrolysis products. Results showed that the oil yield was significantly reduced from 50.1 wt% to 41.2 wt% by ZSM-5 catalyst and 36.0 wt% by Ni/SA catalyst, respectively, with corresponding increases of aqueous and gas products. The addition of Fe particles to ZSM-5 catalyst slightly altered the product yields, whereas the mixture of Fe and Ni/SA catalyst largely reduced the oil yield to 25.6 wt%, along with the highest gas yield of 20.3 wt%. The results suggested that the mixture of Fe-Ni/SA catalyst accelerated the cracking of vapor products derived from PCBs rather than the Fe-ZSM-5 mixture. Moreover, ZSM-5 catalyst favored the formation of single ring aromatics in the oils, such as benzene and toluene. The presence of Fe particles increased the concentration of phenol in the oils. The ZSM-5 and Ni/SA catalyst demonstrated great debromination performance for the conversion of organobromine compounds into HBr, reducing the bromine content in oils from 8.74 wt% to 5.96 wt% and 5.46 wt%, respectively. Furthermore, the addition of Fe particles reduced both the organobromine compounds and evolved HBr, which resulted in less than 3.8% of Br being transferred in the oil whereas more than 50% of bromine was fixed in Fe particles.

Kinetic Modeling of Cellulose Fractional Pyrolysis

The kinetics of cellulose fractional pyrolysis was studied for the first time in the temperature range of 200–900 °C, with 25 °C increment under nitrogen atmosphere. A detailed analysis of the major and minor pyrolysis products was performed using a System for Thermal Diagnostic Studies (STDS) and FTIR techniques. A semiglobal kinetic model was proposed, with products grouped into kinetic lumps, based on their formation profile similarity. Kinetic parameters (pre-exponential factor A and activation energy Ea) for formation of major products grouped into heavy volatiles 1 lump (levoglucosan and anhydrosugars) and light volatiles 2 lump (furans and carbonyls) were obtained based on the performed experimental studies. The final model accurately predicts not only the weight loss, the temperature-distribution of major lumped products, and the total yields of tar and gases from the fractional pyrolysis of cellulose but also shows a good performance toward literature data for experimental studies of others.

Fast pyrolysis of Kraft lignins fractionated by ultrafiltration

The pyrolysis behavior of different lignin samples fractionated by ultrafiltration membrane technology was investigated by pyrolysis–gas chromatography/mass spectrometry (Py–GC/MS). Results indicated that the predominant products derived from pyrolysis of lignin fractions with different molecular weights changed in the relative content, but not in the compound species. At 500°C, high molecular weight lignin favored the generation of guaiacol-type compounds (57.33%), and low molecular weight lignin produced more syringol-type compounds (34.33%). As temperature increased to 650°C, methoxy groups in S and G units were easier to cleave from the benzene ring of the high molecular weight lignin leading to an increase in the relative content of phenol-type compounds. High molecular weight lignin was found to produce the highest amounts of phenol-type compounds (46.22%) and aromatic hydrocarbons (17.25%) at 800°C, while low molecular weight lignin favored the generation of guaiacol-type and syingol-type compounds. The reveal of relevance between specific lignin fractions and pyrolysis behaviour is meaningful for the efficient transformation of lignin to specific aromatic compounds.

Hydrodesulfidation of the diesel fraction of pyrolytic fuel on polymetallic catalyst

Results are presented of a study of the liquid product formed in pyrolysis of automobile tires and fractions of this product. The diesel fraction of the pyrolytic liquid fuel was hydrodesulfided on a polymetallic catalyst. The results of the hydrodesulfidation in a flow-through laboratory installation in the temperature range 320–380°C at a hydrogen delivery rate of 6 L h–1 are shown. The experiment was performed during 1 h with preliminary activation in a flow of hydrogen for 2 h and raw material delivery rate of 4–16 mL h–1 on a polymetallic Al–Ni–V–Mo catalyst supported by γ-Al2O3. It was found that the degree of purification grows by 14% as the delivery rate is lowered from 16 to 8 mL h–1, and by 27% upon its decrease to 4 mL h–1. With temperature varied at the optimal raw material delivery rate of 4 mL h–1, the degree of purification also changes: the minimum degree of purification is observed at 320°C. The degree of purification grows by 7% as the process temperature is raised by 20°, and by 28% upon its increase by 40°.

Molecular Products and Fundamentally Based Reaction Pathways in the Gas-Phase Pyrolysis of the Lignin Model Compound p-Coumaryl Alcohol.

The fractional pyrolysis of lignin model compound para-coumaryl alcohol (p-CMA) containing a propanoid side chain and a phenolic OH group was studied using the System for Thermal Diagnostic Studies at temperatures from 200 to 900 °C, in order to gain mechanistic insight into the role of large substituents in high-lignin feedstocks pyrolysis. Phenol and its simple derivatives p-cresol, ethyl-, propenyl-, and propyl-phenols were found to be the major products predominantly formed at low pyrolysis temperatures (<500 °C). A cryogenic trapping technique was employed combined with EPR spectroscopy to identify the open-shell intermediates registered at pyrolysis temperatures above 500 °C. These were characterized as radical mixtures primarily consisting of oxygen-linked conjugated radicals. A comprehensive potential energy surface analysis of p-CMA and p-CMA + H atom systems was performed using various DFT protocols to examine the possible role of concerted molecular eliminations and free-radical mechanisms in the formation of major products. Other significant unimolecular concerted reactions along with formation and decomposition of primary radicals are also described and evaluated. The calculations suggest that a set of the chemically activated secondary radical channels is relevant to the low temperature product formation under fractional pyrolysis conditions.

Fractional conversion of microalgae from water blooms

Fractional conversion of natural algae cyanobacteria from Taihu Lake was conducted. The raw Taihu Lake algae (TLA) and pretreated samples were pyrolyzed at 290 °C and 450 °C according to the TGA results. Extraction of lipids or saccharides from the TLA was performed as a pretreatment to obtain lipid extracted algae (LEA) or saccharide extracted algae (SEA). The total yields of bio-oil from fractional pyrolysis were 40.9 wt% from TLA, 42.3 wt% from LEA, and 48.5 wt% from SEA. From TLA, the major components of the bio-oil were fatty acids, amides and hydrocarbons (heptadecane) at 290 °C whereas those at 450 °C were phenols and C10-C15 hydrocarbons. Following the lipid extraction, acids, amides and indoles accounted for a large proportion at 290 °C, while the main products obtained at 450 °C were phenols, indoles and pyrroles. It is worth mentioning that the yield of bio-oil from the LEA had increased, and the composition of the bio-oil was simplified. Moreover, the average molecular weight of the bio-oil obtained from LEA had decreased. Interestingly, the extraction of saccharides inhibited pyrolysis of the lipids, so the distribution of the bio-oil from SEA changed only a little. Fractional pyrolysis of pretreated microalgae not only increased the bio-oil yield but also improved the quality of the bio-oil.