Thermogravimetric Analyzer Coupled With Fourier Transform Infrared Spectroscopy Research Articles

Characteristics and kinetics of the gas releasing during oil shale pyrolysis in a micro fluidized bed reactor

This paper presents a comprehensive study on characteristics and kinetics of the gas component (H2, CH4, CO, CO2) releasing during oil shale (OS) pyrolysis. Firstly, the thermogravimetric analysis coupled with Fourier transform infrared spectroscopy (TGA-FTIR) was used to determine the decomposition regions of OS. The results showed that the OS undergoes two pyrolysis regions: first stage (400∼600 °C) and second stage (600∼800 °C). The isothermal pyrolysis of OS was carried out in a micro-fluidized bed reaction analyzer (MFBRA). The evolved temperature and time span of each gas product are different in both sections. Reaction kinetics were investigated with respect to the formation of individual gas component and gas mixture. The kinetics of gas components and gas mixture were calculated by model fitting method. The activation energy (Ea) calculated by the three models for H2, CH4 and CO2 were in the range of 51.05∼60.15, 6.84∼9.65 and 13.21∼14.10 kJ/mol, respectively, while the values varied significantly in high temperature zone. In particular, the resulting Ea values for H2 decreased to 38.88∼40.57 kJ/mol, while that for CH4 and CO2 increased to 25.16∼27.61and 26.12∼35.12 kJ/mol, respectively. However, compared with other three gases, CO only appears in the high temperature zone, and the activation energy of CO is in the range of 32.98∼34.82 kJ/mol. The Ea of the stage 2 is higher than that of the stage 1. The result indicated that the control step gradually transits from the surface chemical reaction control to the joint control of reaction and diffusion with increasing temperature.

Locally Sustainable Biodiesel Production from Waste Cooking Oil and Grease Using a Deep Eutectic Solvent: Characterization, Thermal Properties, and Blend Performance.

As part of local sustainability efforts, biodiesel was synthesized via transesterification using a deep eutectic solvent (DES) without further washing from on-campus, dining facility waste cooking oil and grease. Before moving forward with repurposing used DES as a solvent in chemistry teaching labs, we determined the suitability of the biodiesel as an alternative fuel blended with diesel to power campus utility vehicles. Biodiesel components were characterized by gas chromatography–mass spectrometry (GC–MS), Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (1H NMR), viscometer, differential scanning calorimetry (DSC), and evolved gas analysis during pyrolysis with a thermogravimetric analyzer coupled with FTIR (TGA-FTIR). The four major components of fatty acid methyl esters (FAMEs) in the biodiesel were methyl oleate, methyl linoleate, methyl palmitate, and methyl stearate. Kinematic viscosity over typical temperature ranges was within optimal values recommended by the American Biodiesel Standard (ASTM D6751), with a 30:70 biodiesel/diesel blend experimental viscosity of 3.43 cSt at 40 °C and a calculated viscosity of 10.13 cSt at 0 °C. The pure biodiesel’s cold-temperature onset of crystal formation is −10.1 °C versus −16.4 °C for a 30:70 biodiesel/diesel blend. Pyrolysis indicates good thermal stability, however, with an increased CO2 evolution in the blended fuel at higher temperatures as compared to that in the pure biodiesel and the pure diesel. Combustion gas analysis indicates virtually complete combustion of the blended fuel to CO2 and H2O with only trace amounts of CO. Overall results indicate that the biodiesel synthesized using DES is a suitable fuel for campus utility vehicles in the local moderate temperature climate and affords increased local sustainability by using used DES repurposed in our chemistry teaching labs.

Analysis of Pyrolysis Characteristics and Kinetics of Cigar Tobacco and Flue-Cured Tobacco by TG-FTIR

Summary Investigation of the detailed pyrolysis characteristics of tobacco raw materials is important for the understanding of product design and consumption. In this work, pyrolysis characteristics and kinetic models of cigar filler tobacco (CFT), cigar wrapper tobacco (CWT), and flue-cured tobacco (FCT) were investigated by using a thermogravimetric analyzer coupled with Fourier-transform infrared spectroscopy (TG-FTIR). The pyrolysis of different tobacco samples could be divided into four stages based on the derivative thermogravimetric analysis (DTG) curves. Flue-cured tobacco underwent a marked decomposition process at lower temperatures (about 200 °C), while the thermal decomposition of cigar tobacco occurs at higher temperatures. During the pyrolysis process, evolved gases including H2O, CO2, CH4, CO, carbonyls, alcohols, phenols and aromatic compounds were detected by FTIR. CWT released more CO2 than CFT, while the amount of CO2, CH4, CO and aromatic compounds released by flue-cured tobacco was lower than that of cigar tobacco. The pyrolysis kinetics of tobacco leaves were further analyzed and compared through the isoconversional FWO (Flynn-Wall-Ozawa) and KAS (Kissinger-Akahira-Sunose) methods. The activation energy of FCT (from 100.1 kJ mol−1 to 192.1 kJ mol−1) was lower than that of CFT (from 207.36 kJ mol−1 to 319.28 kJ mol−1) and CWT (from 160.40 kJ mol−1 to 260.45 kJ mol−1). The thermal decomposition kinetics of different tobaccos were analyzed by Málek and Coats-Redfern methods.

Evaluation of thermoanalytical methods equipped with evolved gas analysis for the detection of microplastic in environmental samples

Microplastic particles are currently detected in almost all environmental compartments. The results of detection vary widely, as a multitude of very different methods are used with very different requirements for analytical validity.In this work four thermoanalytical methods are compared and their advantages and limitations are discussed. One of them is thermal extraction-desorption gas chromatography mass spectrometry (TED-GC/MS), an analysis method for microplastic detection that has become established in recent years. In addition, thermogravimetric analysis coupled with Fourier-transform infrared spectroscopy (TGA-FTIR) and mass spectrometry (TGA-MS) were applied, two methods that are less common in this field but are still used in other research areas. Finally, microscale combustion calorimeter (MCC) was applied, a method not yet used for microplastic detection.The presented results are taken from a recently published interlaboratory comparison test by Becker et al. (2020). Here a reference material consisting of suspended matter and specified added polymer masses was examined, and only the results of the recoveries were presented. In the present paper, however, the results for the individual polymers are discussed in detail and individual perspectives for all instruments are shown.It was found that TED-GC/MS is the most suitable method for samples with unknown matrix and unknown, variable kinds and contents of microplastic. TGA-FTIR is a robust method for samples with known matrix and with defined kinds of microplastic. TGA-MS may offer a solution for the detection of PVC particles in the future. MCC can be used as a very fast and simple screening method for the identification of a potential microplastic load of standard polymers in unknown samples.

Pyrolysis behavior and product distribution of exinite submacerals

This paper systematically investigated the pyrolysis behavior and product distributions of exinite submacerals isolated from different low-rank coal using thermogravimetric analyzer coupled with Fourier Transform infrared spectroscopy (TG-FTIR) and Pyrolyzer coupled with gas chromatography/mass spectrometry (Py-GC/MS). The functional groups in exinite submacerals were studied by FTIR simultaneously. Results suggested that all submacerals were less aromatic with abundant aliphatic chains and more oxygen-containing functional groups. Besides, the TG profiles lateral shifted towards higher temperatures with the heating rates. The kinetic parameters (E and A) indicated that the calculated activation energy and frequency factor of the resinite were the largest, and the barkinite was close to cutinite, while the sporinite was the smallest. The release of CO2, CH4, H2O and CO were measured during pyrolysis process. The temperature intervals and contents for these volatile species reflected the difference in pyrolysis mechanism and the contents of functional groups for different submaceral. According to the fast pyrolysis (650 ℃) by Py-GC/MS, the volatile species could be classified into eight categories including alkanes, alkenes, cycloalkanes, arenes, alcohols, phenols, heteroatomic compounds and ketones. The pyrolysis behavior and product distributions of submacerals were closely related to the chemical structure of its special parent material. The sensitivity of different chemical structures in exinite submacerals to temperature achieved different trends of pyrolysis behavior and product distribution.

Investigation on the thermal degradation behavior of enzymatic hydrolysis lignin with or without steam explosion treatment characterized by TG-FTIR and Py-GC/MS

In this study, enzymatic hydrolysis lignin (EHL) extracted from bio-ethanol production residue by enzymatic hydrolysis method was utilized as the raw material, which was subsequently purified to remove cellulose and hemicellulose for gaining the purified lignin (EHL-P) through alkaline solution extraction. Compared with EHL-P, thermal performance and pyrolytic product distribution of EHL-P-SE (which was obtained from EHL-P by steam explosion) were also analyzed by thermogravimetric analyzer coupled with Fourier transform infrared spectroscopy (TG-FTIR) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). Results showed that the degradation process of EHL-P and EHL-P-SE was similarly divided into three stages: a drying stage, a rapid decomposition stage, and a slow carbonization stage. However, their initial weight loss (i.e., ˂ 3 wt% for EHL-P, while ~ 5 wt% for EHL-P-SE before 200 °C), primary weight loss (i.e., ~ 55 wt% for EHL-P, while ~ 48 wt% for EHL-P-SE between 200 and 600 °C), and char yields (i.e., ~ 33 wt% for EHL-P, while ~ 42 wt% for EHL-P-SE at 900 °C) were different. FTIR showed that the evolution of gaseous products changed significantly due to the effect of SE treatment, especially for organic components (i.e., the absorbance of peaks corresponding to carbonyl-containing components such as aldehydes, ketones, and acids decreased, while that related to phenols and aromatics increased). Finally, Py-GC/MS tracked variations of the relative content (%) of phenols (e.g., guaiacol (G), phenol (P), syringol (S), and catechol (C) types) with the increase of degradation temperature (from 300 to 500 °C), and results showed that demethoxylation was more likely to occur at higher degradation temperatures (≥ 400 °C) to realize the transformation from G- and S-type phenols to P- and C-type phenols.

Kinetics and mechanism of thermal degradation of aldehyde tanned leather

The thermal degradation of hides before and after tanning with formaldehyde and glutaraldehyde were studied using thermogravimetric analyzer (TGA) and TGA coupled with Fourier transform infrared spectrometry (TGA-FTIR). TG-FTIR analysis indicated that the pyrolysis products of both untanned hides and tanned leathers are mainly CO2, NH3, and CO contained organic components with some HNCO, CH4 and H2O. Compared to that of untanned hides, the peak intensity of evolved NH3 from formaldehyde tanned one is enhanced, while the evolved temperature decreases from 220 °C to 200 °C. The evolution of CO contained organic components is increased due to the introduction of carbonyl groups after formaldehyde tanning. However, for the glutaraldehyde-tanned leather, the evolution peak intensity of CO contained organic components decreases with more CO2 yield, suggesting that the carbonyl groups introduced by glutaraldehyde-tanning is mainly changed to CO2 rather than CO contained organic components. The kinetic analysis of thermal degradation process of the hides and tanned leathers are also investigated by using the methods of Flynn-Wall-Ozawa, Friedman and Criado. Results indicated that the thermal degradation process can be described by the three-dimensional diffusion model (D3) at the conversion below 0.5. Whereas, at the conversion above 0.5, this process turns to comply random nucleation model (F3).

Thermal behavior and kinetics of enzymatic hydrolysis lignin modified products

Enzymatic hydrolysis lignin (EHL) used in this experiment was extracted from the bio-ethanol production residue by enzymatic hydrolysis method. With different modification methods, the purpose of this paper was to investigate the pyrolysis behavior and kinetics of lignin modified products via thermogravimetric analyzer coupled with Fourier transform infrared spectrometry (TG-FTIR). The emergence of specific functional groups detected by FTIR predicted that specific functional groups was grafted onto lignin successfully. Thermogravimetry/derivate thermogravimetry (TG/DTG) results showed that only the pyrolysis process of Lig-F (one of lignin modified products) was similar to that of Lig-C (purified lignin), and pyrolysis processes of other lignin-modified products had changed greatly. Moreover, pyrolysis properties of lignin modified products were different because of different grafting functional groups. In addition, the kinetics of Lig-F was conducted by two kinetic models (FWO: Flynn-Wall-Ozawa and KAS: Kissinger-Akahira-Sunose). Both methods obtained analogous values of activation energy, ranging from 157 kJ mol−1 to 219 kJ mol−1. This paper also gave a further evaluation of the application of lignin modified products in the field of flame retardants, which would better promote the multi-functional application of lignin.

The Influence of Environmentally Friendly Flame Retardants on the Thermal Stability of Phase Change Polyurethane Foams.

To improve thermal insulation, microencapsulated phase change materials (micro-PCMs), expandable graphite (EG), and ammonium polyphosphate (APP) were introduced into polyurethane foam (PUF) to enhance the thermal stability and improve the thermal insulation behavior. The morphology of the PUF and micro-PCM was studied using a scanning electronic microscope (SEM), while the thermophysical properties of the PUF were investigated using a hot disk thermal constants analyzer and differential scanning calorimetry (DSC). The thermal stability of the PUF was investigated by thermogravimetric analysis (TGA), and the gas products volatilized from the PUF were analyzed by thermogravimetric analysis coupled with Fourier transform infrared spectrometry (TGA-FTIR). The results revealed that the thermal conductivities of the PUF were reduced because micro-PCM is effective in absorbing energy, showing that the PUF functions not only as a thermal insulation material but also as a heat sink for energy absorption. Moreover, the EG and APP were found to be effective in improving the thermal stabilities of the PUF, and the optimized formulation among EG, APP, and micro-PCMs in the PUF showed a significant synergistic effect.

Chemical looping combustion of lignite with the CaSO4–CoO mixed oxygen carrier

Chemical looping combustion (CLC) has well developed as a novel combustion technology for simultaneous completion of the coal combustion and CO2 capture with a low energy penalty. Among all the oxygen carriers available, CaSO4 has gained great attention as a promising oxygen carrier (OC) in CLC due to its high oxygen capacity and low price. But further application of CaSO4 OC also suffers the problems of low reactivity and even deactivation due to the sulfur loss via the side reactions of CaSO4, which should be well addressed. In this research, the CaSO4–CoO mixed OC was prepared firstly, and experiments based on thermogravimetric analyzer coupled with Fourier transform infrared spectroscopy (TG-FTIR) were conducted to evaluate the reaction characteristics and evolution of the gaseous products during the reaction of the prepared CaSO4–CoO mixed OC with lignite (abbreviated as YN). Both the higher reaction rate of the prepared mixed OC with YN coal and the elevated CO2 concentration fully reflected the enhanced reactivity of the prepared mixed OC for YN coal conversion. Furthermore, the micromorphology of the solid reaction products was analyzed by the field emission scanning electron microscopy spectrometry (FESEM). Good sintering resistance of the prepared CaSO4–CoO mixed OC during its reaction with YN was verified, which was ascribed to the temporary inert support role played by the CaSO4 substrate. In order to further study the desulfurization ability of CoO in the mixed OC, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and thermodynamic simulation were used for in-depth analysis. The gaseous sulfur species released by the CaSO4 side reactions were mainly fixed as solid CoS, Co9S8 and CaS, with the total content higher than 99.8%. And the sulfided OC could be completely regenerated to its original state at the oxidation stage according to the X-ray diffraction (XRD) result. Overall, the prepared CaSO4–CoO mixed OC not only has the enhanced reactivity and good sintering resistance, but also owns the potential to control sulfur released from the CaSO4 side reactions, which has broad application prospect to simultaneously achieve decarbonization and desulfurization in the CLC process.

Experimental investigation on combustion behaviors and reaction mechanisms for 5-aminotetrazole solid propellant with nanosized metal oxide additives under elevated pressure conditions

5-AT/Sr(NO3)2 based composite propellants have been applied in fire extinguishing fields as novel power source for several years due to its high thermal stability and large gas production, but the disadvantage of poor combustion stability still indeed to improve. In this study, the influential mechanism of two common burning modifier, nanosized Copper oxide (nano-CuO) and nanosized Zinc oxide (nano-ZnO), on the thermal behavior and combustion characteristics under high pressure of 5-AT based composite propellant was deeply investigated. Simultaneous thermogravimetric-differential thermal analysis (TG-DTA) have been used to identify the changes in the thermal and kinetic behavior of the catalyzed composite propellant. Thermogravimetric analyzer coupled with Fourier transform infrared spectrometry (TG-FTIR) analysis and pyrolysis-gas chromatography with mass spectrometry (Py-GC/MS) analysis were employed to characterize the composition of evolved gas in propellant decomposition process. Combined with results of the combustion characteristics measurement conducted on a strand burner (1–5 MPa), different kinds of influential mechanisms of these two catalysts on decomposition process and combustion process under elevated pressure conditions were proposed based on presumed physical combustion model. Outcomes of this study will contribute to the design of 5-aminotetrazole solid propellant with a superior combustion property under high pressure, and promote its application into fire-fighting area.

Pyrolysis behaviors and product distribution of Shengli Lignite at different heating rate and final temperature by TG-FTIR and Py-GC-MS

ABSTRACT The slow pyrolysis characteristics of Shengli lignite (SL) from ambient temperature to 800°C at heating rates of 20°C/min and 100°C/min were investigated by thermogravimetric analysis coupled with Fourier transform infrared spectrometry (TG-FTIR) and by pyrolysis coupled with gas chromatography-mass spectrometry (Py-GC-MS). The final temperatures had larger effect on the pyrolysis products. The pyrolysis at 800°C of 20°C/min and 100°C/min (from the Py-GC-MS) obtained a variety of aliphatic compounds and monocyclic aromatic compounds, including short-chain olefins, alcohols, and ketones. But at 400°C, almost no short-chain aliphatic compounds were obtained, and a faster heating rate (100°C/min) was beneficial for obtaining long-chain aliphatic alkanes, alcohols, and acids (n-Hexadecanoic acid and Octadecanoic acid). It provides evidence that the aliphatic chains in lignite structure were long-chain, and the short-chain aliphatic compounds were from the secondary decomposition. The bicyclic compounds, monocyclic aromatic compounds were always important products. The real-time FTIR showed obvious differences in the pyrolysis at different heating rates. In the slower pyrolysis process (20°C/min), the absorbance of CO2 was much higher than that in the other processes, but in the faster pyrolysis process (100°C/min), the diversity of the pyrolysis products was substantially improved by the -OH, C = O, -COOH, C-CH3 and aromatic C-H functional groups, so maybe more valuable gas/liquid products could be produced at larger heating rate. The products at some specific temperatures (from the DTG peaks) were also provided for the reaction analysis.

New Perspective on Wood Thermal Modification: Relevance between the Evolution of Chemical Structure and Physical-Mechanical Properties, and Online Analysis of Release of VOCs.

Thermal modification (TM) is an ecological and low-cost pretreated method to improve the dimensional stability and decay resistance of wood. This study systematically investigates the relevance between the evolution of chemical structure and the physical and mechanical properties during wood thermal modification processes. Moreover, the volatility of compounds (VOCs) was analyzed using a thermogravimetric analyzer coupled with Fourier transform infrared spectrometry (TGA-FTIR) and a pyrolizer coupled with gas chromatography/mass spectrometer (Py-GC/MS). With an increase of TM temperature, the anti-shrink efficiency and contact angle increased, while the equilibrium moisture content decreased. This result indicates that the dimensional stability improved markedly due to the reduction of hydrophilic hydroxyl (–OH). However, a slight decrease of the moduli of elasticity and of rupture was observed after TM due to the thermal degradation of hemicellulose and cellulose. Based on a TGA-FTIR analysis, the small molecular gaseous components were composed of H2O, CH4, CO2, and CO, where H2O was the dominant component with the highest absorbance intensity, i.e., 0.008 at 200 °C. Based on the Py-GC/MS analysis, the VOCs were shown to be mainly composed of acids, aldehydes, ketones, phenols, furans, alcohols, sugars, and esters, where acids were the dominant compounds, with a relative content of 37.05−42.77%.

Facile preparation of activated carbon foam via pyrolysis of waste bread under CO2 atmosphere

Activated carbon foam was prepared via direct pyrolysis of waste bread (WB) under CO2 atmosphere. The product was characterized by N2 adsorption/desorption and Fourier transform infrared spectroscopy (FTIR). The preparation process was investigated online by a thermogravimetric analyzer coupled with FTIR (TG-FTIR). The adsorption isotherms of methylene blue (MB) by the product were investigated. The experimental data demonstrated that the product had a high surface area of 1575 m2 g−1 and a total pore volume of 0.883 cm3 g−1. Thermal decomposition of polymers in WB mainly occurred between 200 and 500 °C, leading to the release of carbonyl compounds, aliphatic hydrocarbons, alcohols, and furans. The dominant CO2 activation process started at above 800 °C. The MB adsorption equilibrium data followed Langmuir model with a monolayer adsorption capacity of 403 mg g−1. This study provides a reference for the utilization of WB as a promising precursor of activated carbon foam adsorbent, which has highly porous structure and excellent floatability in water.

Separation of petroleum ether extracted residue of low temperature coal tar by chromatography column and structural feature of fractions by TG-FTIR and PY-GC/MS

The petroleum ether extracted residue (PCT) of the low temperature coal tar were separated and analyzed in this study. PCT was stepwise separated into toluene eluent (TS), ethanol eluent (EAS), methanol eluent (MAS), tetrahydrofuran eluent (THFS) and residue (IS) by chromatography column (CC) with Al2O3. Their composition and structure feature were confirmed by gel permeation chromatography (GPC), Uv-fluorescence, thermogravimetric analyzer coupled with Fourier transform infrared spectroscopy (TG-FTIR), pyrolysis gas chromatography-mass spectrometer (PY-GC/MS) and Fourier transformed infrared (FTIR). The results show that the yields of TS, EAS, MAS, THFS are 1.70 wt%, 33.22 wt%, 18.97 wt% and 1.41 wt%, respectively. The order of their molecular weights from small to large is as follows: MAS < PCT < TS < EAS < THFS. The compound types of pyrolysis volatiles from TS, EAS, MAS and IS change completely with the temperature rising. TS pyrolysis volatiles mainly contain oxygen compounds and nitrogen compounds. EAS pyrolysis volatiles mainly contain aromatic hydrocarbons and oxygen compounds·THFS pyrolysis volatiles mainly contain aliphatic hydrocarbons (C33-C43 alkanes), and their average content is 82.39 wt%. The pyrolysis temperature from 500 °C to 600 °C is the cut-off point, at which light aromatic hydrocarbons and low boiling phenols are detected, and they may connected by bridge bonds.

Thermo-kinetics and gaseous product analysis of banana peel pyrolysis for its bioenergy potential

This study illustrated the pyrolysis of banana peel (BP) as a potential waste management solution. Samples were characterized through Fourier transform infrared spectrometry (FTIR), elemental analysis, and high heating value (HHV) calculation. After pyrolysis experiments were performed at different heating rates (10, 20, 30, and 40 °C min−1) by using a thermogravimetric analyzer coupled with FTIR (TG-FTIR), the apparent activation energies were computed with Friedman, Kissinger–Akahira–Sunose (KAS), and Flynn–Wall–Ozawa (FWO) methods, and the evolved gaseous products were analyzed simultaneously. During pyrolysis, BP underwent three devolatilization steps accompanied by the evolution of some major gaseous products, including CO2, CH4, H2O, CH3COOH, CC, C6H5OH, HCOOH, and CH3CH2OH. Among them, CC, CH3COOH, and CO2 accounted for approximately 71.56% of the total gaseous products. Gas evolution was more significantly influenced by the pyrolysis temperature than by the heating rate. Pyrolysis–gas chromatography/mass spectrometry (Py-GC/MS) analysis confirmed the presence of some high-energy compounds and valuable chemicals containing aromatic, aldehyde, ketone, and other functional groups. In terms of preliminary energy balance, more than 70% of the total energy output was attributed to the liquid pyrolytic products followed by the solid and gaseous products. The energy recovery ratio of BP pyrolysis was superior to that of other fuel feedstocks. This work provided insights into resolving environmental problems associated with BP management by pyrolyzing BP as a potential source of renewable bioenergy.

Pyrolysis behaviors and product distribution of Shenmu coal at high heating rate: A study using TG-FTIR and Py-GC/MS

The chemical properties, pyrolysis behaviors and pyrolysis product distributions of Shenmu (SM) coal were investigated by proximate and ultimate analysis, thermogravimetric analyzer coupled with Fourier transform infrared spectroscopy (TG-FTIR) and Pyrolyzer coupled with gas chromatography/mass spectrometry (Py-GC/MS). The results of the proximate and ultimate analysis indicated that SM coal had less saturated aliphatic structures and more polar components. The coke yield for SM coal during pyrolysis process at 100 °C/min, 300 °C/min, and 500 °C/min was 65.60%, 64.19%, and 63.15%, respectively, which indicating that the increment in heating rates could promote the production of volatile substances. Moreover, there was a lateral shift to high temperature of TG/DTG curves when the heating rates increasing. The main volatile species detected from FTIR in the pyrolysis of SM coal were CO2, CO, CH4, C2H4, C2+ aliphatics, light arenes, CO bond containing species and CO bond containing species. Since the difference in the temperature intervals of those volatile species released, the sources of cleavage or chain scission during pyrolysis process were not the same. According to the fast pyrolysis by Py GC/MS, the volatile species could be divided into eleven species including alkenes, cycloalkenes, alkanes, cycloalkanes, aromatics, phenols, ethers, ketones, alcohols, N-containing species, and other species. The relative contents of alkenes and alkanes were dominant regardless of the variegation of heating rate, residence time and pyrolysis final temperature. Furthermore, the trend of each species under different influence factor conditions achieved different tunes rendered with equal skill.

TGA-FTIR analysis of Upper Assam oil shale, optimization of lab-scale pyrolysis process parameters using RSM

This paper presents a comprehensive study on the in line analysis of products formed during pyrolysis of oil shale from Upper Assam, India and optimization of lab-scale pyrolysis parameters. Thermogravimetric analysis coupled with Fourier transform infrared spectroscopy (TGA-FTIR) was used to determine the decomposition zones and investigate the products evolved during pyrolysis. Study of the evolved gases showed the presence of CH stretching, CC aromatic bending, OH, CO2, and SO2. Response surface methodology (RSM) was employed using central composite design (CCD) model to setup the lab-scale experiment using TGA data, and optimization of process parameters viz. heating rate, temperature and particle size. The pyrolytic shale oil obtained at optimum condition was subjected to characterization using gas chromatography and mass spectrometry (GC–MS) and nuclear magnetic resonance spectroscopy (NMR). The produced shale oil showed an abundance of aliphatic compounds corresponding to high energy density.

An effective multi-hydroxy-containing ammonium phosphate towards flame-retarding poly(lactic acid): Flame retardance, thermal and pyrolysis behaviors

To retard the flammability of poly(lactic acid) (PLA), a multi-hydroxy-containing ammonium phosphate (DPPT) derived from 2-chloro-5,5-dimethyl-1,3,2-dioxaphosphinane-2-oxide (DOP) and trihydroxymethyl aminomethane (TRIS) through a one-pot reaction was introduced. By comparison with PLA, the limiting oxygen index (LOI) of PLA modified with 2.5% DPPT increased from 19.5% to 32.7%, and UL-94 vertical rating was improved from no rating to UL-94 V-0 rating. Besides, the results of cone calorimetric tests (CC) showed that DPPT could suppress the heat release of PLA during combustion to some extent. Although the thermal behaviors of PLA were affected by DPPT, DPPT could promote the degree of crystallinity of PLA. According to the relevant results as well as the analyses of thermogravimetric analysis coupled with fourier transform infrared spectroscopy (TG-FTIR) and pyrolysis-gas chromatograph/mass spectrometer (py-GC/MS), the flame retardant mechanism of DPPT was also disclosed that it could decompose to generate the incombustible compounds such as water and ammonia, and simultaneously release phosphorus-containing free radicals; Besides, the removal of nonflammable dripping could also bring away heat and cut off the heat-transfer to the matrix.

Comparison of the thermal degradation behaviors and kinetics of palm oil waste under nitrogen and air atmosphere in TGA-FTIR with a complementary use of model-free and model-fitting approaches

Palm oil waste from palm oil industry is a promising biomass resource for bio-fuels and bio-chemicals production by biomass thermochemical conversion technology. In this paper, thermogravimetric analyzer coupled with fourier transform infrared spectrometry (TGA-FTIR) were used to investigate the difference of the thermal degradation behaviors and kinetics of palm kernel shell under nitrogen and air atmosphere. Based on the TG analysis, the weight loss in the third stage with the air atmosphere was higher than the nitrogen atmosphere, presenting as weight loss of 12.4wt.% in the carbonization stage of nitrogen atmosphere and 36.9wt.% in combustion stage of air atmosphere. Based on the 3D-FTIR analysis, the dominant components in the nitrogen atmosphere was CO2, CO bond contained organics, and CH or CO bond contained organics, while CO2 and H2O in the air atmosphere. The evolution and formation mechanism of non-condensable inorganic gaseous components (H2O, CH4, CO2 and CO) in the two atmospheres were remarkably different. The H2O and CO2 were mainly contributed by the breakage of OH group and the cracking/reforming reaction of CO and COOH groups in the nitrogen, however higher contents of H2O and CO2 were observed because of the combustion reaction in the air. The CH4 and CO were mainly contributed by the decomposition of OCH3, CH3, CH2 groups and the cracking of carboxyl group in the nitrogen, while the content of CH4 decreased by the diluting of H2O and CO2, and the CO increased by the incomplete combustion reaction in the air. The kinetic triple (mechanism function, activation energy, and pre-exponential factor) was estimated by the combined use of model-free (Ozawa and Kissinger) and model-fitting (Šatava-Šesták) method.