DTG Curves Research Articles

In English

X-ray phase and thermogravimetric analysis, scanning electron microscopy and energy-dispersion spectroscopy were used to study the products of phase formation during the precipitation of lanthanum and cerium salts in the presence of silver nitrate and recipients of precipitators, nucleating agents and hydrolysis regulators. Thermogravimetric analysis shows the completion of the La(OH)3 lattice dehydroxylation process at a temperature of ~ 300 °С and probable destruction of sulfates at a temperature of ~ 340 °С. The phase interaction of lanthanum oxide(III) with silver ends at T ~ 400 °C. The DTG curve shows a two-stage weight loss, which characterizes the destruction of lanthanum and silver hydroxides (250 °C) and the removal of sulfates (~ 340 °C), respectively. According to the TG, the total weight loss is 21.6 %. For the cerium-containing system the only endothermic effect of dehydroxylation of cerium hydroxide at T = 250 °C with its conversion into cerium dioxide is observed. The destruction of nitrates (anionic component of solutions) takes place at the temperature of 400 °C. Weight loss takes place at T = 150 °C and is 53.9 %. Thus, on the basis of TG-DTA data, it can be assumed that the formation of composites particles based on lanthanum and cerium oxides, modified with silver, ends at the temperature of 400 °C. The X-ray diffraction data shows that at the initial stage the system undergoes the formation of cerium and lanthanum hydroxides, and during lyophilization of the precipitate (T = 160 °C) the crystal lattice of hydroxides partial dehydroxylation takes place with the formation of trigonal oxides La2O3 and Ce2O3. It has been found that the presence of silver cations in the solution can affect the phase composition of lyophilized structures and the formation of the CeO2 phase. It is shown that the hydroxylamine chloride injection into the system can initiate the silver restoration on the lanthanum oxide surface and also partially restore it to the LaO phase. Temperature treatment of the samples (T = 400 °С) promotes homogenization of the precipitate composition: formation of 30 nm cerium dioxide particles with silver clusters evenly distributed on its surface, and hexagonal lanthanum oxide plates with individual silver particles as the second phase. In three-component systems, two modifications of lanthanum oxides (trigonal and cubic), cerium dioxide and metallic silver are formed. It is found that the chemical composition of the precipitates contains the main elements – La, Ce, O, Ag and impurity – S or Cl, as the anionic component of the initial solutions, N and K in the composition of the initial suspension. It is shown that the morphology of the samples is represented by hexagonal structures of lanthanum hydroxide and oxide, spherical and pseudocubic particles of cerium dioxide and lanthanum oxide, spherical clusters of silver.

The Usefulness of X-ray Diffraction and Thermal Analysis to Study Dietary Supplements Containing Iron.

X-ray powder diffraction (XRPD) and thermal analysis (differential scanning calorimetry/derivative of thermogravimetry (DSC/DTG)) are solid-state techniques that can be successfully used to identify and quantify various chemical compounds in polycrystalline mixtures, such as dietary supplements or drugs. In this work, 31 dietary supplements available on the Polish market that contain iron compounds, namely iron gluconate, fumarate, bisglycinate, citrate and pyrophosphate, were evaluated. The aim of the work was to identify iron compounds declared by the manufacturer as food supplements and to try to verify compliance with the manufacturer’s claims. Studies performed by X-ray and thermal analysis confirmed that crystalline iron compounds (iron (II) gluconate, iron (II) fumarate), declared by the manufacturers, were present in the investigated dietary supplements. Iron (II) bisglycinate proved to be semi-crystalline. However, depending on the composition of the formulation, it was possible to identify this compound in the tested supplements. For amorphous iron compounds (iron (III) citrate and iron (III) pyrophosphate), the diffraction pattern does not have characteristic diffraction lines. Food supplements containing crystalline iron compounds have a melting point close to the melting point of pure iron compounds. The presence of excipients was found to affect the shapes and positions of the endothermic peaks significantly. Widening of endothermic peaks and changes in their position were observed, as well as exothermic peaks indicating crystallization of amorphous compounds. Weight loss was determined for all dietary supplements tested. Analysis of the DTG curves showed that the thermal decomposition of most food supplements takes place in several steps. The results obtained by a combination of both simple, relatively fast and reliable XRPD and DSC/DTG methods are helpful in determining phase composition, pharmaceutical abnormalities or by detecting the presence of the correct polymorphic form.

Experimental and Kinetic Studies on Tobacco Pyrolysis under a Wide Range of Heating Rates.

In the present work, experimental and kinetic studies are conducted to explore and model tobacco pyrolysis characteristics under a wide range of heating conditions. First, thermal decomposition processes of a tobacco sample were investigated using thermogravimetric analysis/difference thermogravimetry (TGA/DTG) experiments under a wide range of heating rates (10–500 K/min), and the TGA/DTG profiles were compared to highlight the effect of heating rate on the pyrolysis characteristics. The results showed that the tobacco sample was sufficiently devolatilized at 1173.15 K (900 °C) and the final volatiles yields were not sensitive to the heating rate. Moreover, it was illustrated that the DTG curve presents a polymerization trend with the increase in heating rate. Then, kinetic parameters, including total component mass fraction, preexponential factor, and activation energy, were derived by deconvolution from TG/DTG profiles for each component with a one-step kinetic framework, and the correlations between kinetic parameters and heating rates were further explored and modeled. The results illustrated that four subpeaks can be found in the deconvolution, indicating the four components (volatile components, hemicellulose, cellulose, and lignin). In addition, the activation energy of each component was found to be insensitive with heating rate (with standard deviation less than 20%). Therefore, an average activation energy was used for each component to avoid the compensation effect and a power correlation between the heating rate and the preexponential factor could be found. A posteriori analysis also confirmed the validity of this correlation.

Insight into the charging methods effects during clean recycling of plastic by co-pyrolysis with low-rank coal

Co-pyrolysis of waste plastic and low-rank coal provides a promising method for high-efficiency utilization of them. Previous studies about co-pyrolysis of plastic and low-rank coal mainly concentrated on evenly physical mixture (PM) of feedstock. It has been found that the uneven distribution of materials in the reactor could be caused by the apparent differences in density and property between plastic and coal. In order to investigate the effects of interaction strength between coal and plastic on the thermal behavior and properties of products, a set of co-pyrolysis experiments with different charging methods of one Chinese low-rank coal and high density polyethylene (HDPE) were carried out. To be specific, the charging methods of PM and layered placement (LP), which include charging coal on top of plastic (CT), plastic in the middle of coal like a hamburger (HB) and plastic on top of coal (PT). Results show that, with the same plastic addition ratio, the weight loss of LP co-pyrolysis has almost no reduction compared with that of PM and only one peak is observed from DTG curves instead of two peaks as shown in the theoretical calculated (Cal) curve. It means that there is still an obvious interaction between coal and plastic during co-pyrolysis. Compared to the charge of PM, the tar yield of LP co-pyrolysis decreases slightly while enhances the char yield. The properties of char samples of LP show no noticeable differences as compared that of PM. In term of tar products, co-pyrolysis with HDPE increases the H/C atomic ratio of tar from 1.286 to 1.480 compared to coal pyrolysis alone. However, charging methods make little difference in H/C atom ratio of tar in co-pyrolysis reactions, which is around 1.50. On the other hand, the content of heavy components in tar obtained from LP co-pyrolysis reduces obviously, which is 18.06%, 22.83% and 26.76% for CT, HB and PT, respectively, compared to 36.60% for that of PM. Simultaneously, LP co-pyrolysis can effectively reduce the molecular weight of tar. Additionally, compared to the PM case, the content of H2 and light hydrocarbons (CnHm with n < 5) of LP co-pyrolysis decrease from 10.70% to 7.59% and from 24.56% to 21.67%, respectively. This results from the more effective utilization of H element in the feedstock, especially with the charge of CT. Thus, charging the coal on the top of plastic is a promising method of improving the quality of tar.

Thermomechanical properties of epoxy resin/basalt fiber/hydrotalcite composites and influence of hydrotalcite particle size on their properties

AbstractNatural fibers (NFs) and inorganic particles have been successfully grown in the polymer to enhance its properties. The basalt fiber (BF) and modified hydrotalcite (LDHs) reinforced epoxy resin matrix composites were prepared, and the effects of fiber and modified hydrotalcite (G‐LDHs) on the microstructural characteristics of composites were investigated. Fourier transform infrared spectroscopy and X‐ray diffraction were respectively used to analyze the structure of modified BF and G‐LDHs, and thermogravimetric analysis was performed to study thermal stability. The mechanical properties of composites, including dynamic thermomechanical and tensile and flexural properties, were respectively studied by dynamic mechanical analysis (DMA) and universal testing machine. Experimental results show the successful synthesis of high‐performance epoxy copolymers. The impact strength, tensile strength, and elastic modulus of EP/BF/G‐LDHs respectively reached 7.07 kJ/m2, 20.52 MPa, and 2595 MPa when the content ratio of BF to hydrotalcite in the additive was 3:3. The DMA test showed that the glass transition temperature (Tg) value increased by 18.3°C, and the thermal stability of composite materials was improved. The storage modulus E′ value increased by 268.04 MPa, and the stiffness of the epoxy material and the mechanical properties were also elevated. The TGA and DTG curves indicate that the cured composites also exhibit excellent thermal stability. The effect of g‐LDHS particle size on the properties of composites was also discussed. Overall, the synergistic and complementary enhancement effect of the two materials is the best when the diameter of hydrotalcite is similar to that of BF, and the performance of the composite material is considerably improved.

Autocatalytic influence of different levels of arsine on the thermal stability and pyrolysis of polypropylene

In this article, the pyrolysis and thermo-degradation of 11 virgin-polypropylene (virgin-PP) with different levels of arsenic in its polymer matrix, was carried out in a discontinuous quartz reactor at 500 °C. To quantify arsine (AsH3), 4 points were sampled during the PP synthesis process and a methodology was applied by GC with 4 detectors, which simultaneously and with a single injection allowed to quantify multiple components. AsH3 in propylene varied between 0.05 and 4.73 ppm and arsenic in virgin-PP residues between 0.001 and 4.32 ppm for PP0 and PP10. These generated an increase in the melt flow index from 3.0 to 24.51 and maintained a direct relationship with an R2 of 0.9993. The origin of thermo-oxidative degradation and the beginnings of virgin-PP pyrolysis are explained by the formation to aldehyde, ketone, alcohol, carboxylic acid functional groups, CO and CO2. These species caused TG and DTG curves to have atypical behavior for PP. For example, PP10 with an arsenic content of 4.32 ppm presented 3 degradation peaks at 80, 90 and 200 °C with a mass loss ratio of 22%, 18% and 55% °C−1 respectively. During pyrolysis the highest percentage of alkanes was found in PP0 with an average value of 62.4%, and the lowest values were found in PP8 to PP10, with oscillations between 0% and 1.4%. The total concentration of oxidized species for PP0 to PP10 was 2.26%, 32.7%, 43.1%, 50.9%, 59.3%, 66.2%, 75.0%, 83.0%, 89.1% and 97.5% respectively. In an O2 atmosphere ketones and carboxylic acids were only identified in PP0 to PP5. CO2 concentrations in PP5 to PP10 were of 100%.

Effect of small molecule compounds on the pyrolysis behavior of coal

The effect of small molecule compounds on the pyrolysis behavior of coal are discussed by comparing TG and DTG curves of Yanzhou coal and its tetrahydrofuran (THF) extracted residual in this paper. Based on the thermal gravimetric analysis of Yanzhou coal and its THF extracted residual, it is revealed that part of chemical bonds are weakened after the small molecular compound are extracted in coal, which promotes the pyrolysis of its THF extracted residual. The optimum reaction temperature is 490 oC for the high temperature fast liquefaction of the THF extracted residual. The maximum temperature of weight-loss rate for Yanzhou Coal and its THF extracted residual is 439 oC and 437 oC, respectively. The liquefaction reaction temperature of them is 389-490 oC and 380-525 oC,respectively. The results we studied could can give some help to the further perfection of the theory of the pyrolysis behavior of coal, and its application. And it is further helpful to study the mechanism of the theory of the pyrolysis behavior of coal.

New strategies to quantify aluminum hydroxide in powder coatings by thermogravimetric analysis and ATR-FT-MIR spectroscopy coupled with chemometrics

Powder coatings industry is a growing trade sector in our days and the process control phase is a critical step with the increasing necessity for rapid methods. In this research, we evaluated the possibility of aluminum hydroxide quantification in powder coatings using thermogravimetric analysis and ATR-FT-MIR spectroscopy. Spiked powder coatings sample standards were realized with a known amount of aluminum hydroxide from 0 to 22% in weight. The thermogravimetric analysis (TGA) was optimized, and the aluminum hydroxide content was determined with a stoichiometric formula based on the delta at the inflection point (DTG curve were derived) in TGA results. The spectroscopic data were acquired, and multivariate regression (Partial Least Squares Regression) was used to model the aluminum hydroxide content with respect to the spectral signal. Models were validated with an external set of real powder coating samples. In this article, a step-by-step model development procedure is illustrated as well as the issues addressed. In addition, models showed the possibility of identifying some additives and resins using only the spectroscopic information.

STUDY OF THE PYROLYSIS KINETICS AND ENERGY CONTENT OF ACID WASHED RICE HUSK SAMPLE USING ISOCONVERSIONAL METHODS

The rice husk was characterized by proximate and ultimate analysis. The proximate analysis was determined by moisture, volatile and ash content as 15.48%, 57.28% and 15.35% respectively. Ultimate analysis was determined using the data obtained from proximate analysis to calculate carbon, hydrogen, nitrogen and oxygen percentage as 43.67%, 4.64%, 0.956% and 35.78% respectively. The rice husk pyrolysis was studied by TGA/DTG analysis in a nitrogen atmosphere at flow rate of 60mL/minute, heating from 20.00 oC to 1000.00 oC at three different heating rates: 10, 15 and 20 oC/minute. The devolatilization and decomposition pattern portray by TGA curve for all the samples were almost the same, however, different peak temperatures were shown by DTG curve differently for all the samples at different heating rates. The sample RHC ran at three different heating rates: 10, 15 and 20 oC/minute with peak temperatures of 260.85 oC, 318.14 oC and 358.57 oC respectively. While the acid modified samples RHL and RAA at the same heating rates of 10, 15 and 20 oC/minute with peak temperatures of 402.05 oC, 343.91 oC and 280.76 oC respectively for sample RHL. And 399.34 oC, 325.59 oC and 282.61 oC respectively for sample RAA. Three kinetic models were used in this research, which are known as model fit methods for kinetics. The models are Flynn Wall Ozawa (FWO), Kissinger Akahira Sunose (KAS) and Coats Redfern methods. The KAS and FWO methods were used for the determination of activation energy and C-R method for the reaction mechanisms

Preparation of porous carbon materials from biomass pyrolysis vapors for hydrogen storage

A novel method for preparing porous carbon materials from biomass pyrolysis vapors with calcium citrate template has been proposed. The effects of pyrolysis temperature, pyrolysis heating rate and carbon-containing precursor preparation temperature on the yield of biomass pyrolysis products, composition of light bio-oil and structure of porous carbons were investigated. The physicochemical characterization and hydrogen adsorption experiments were carried out for the prepared porous carbons. The carbonization mechanism of the carbon-containing precursor was studied and a five-stage reaction kinetic model was established by Gaussian peak separation method according to the DTG curves. Under the optimal conditions of pyrolysis temperature (823 K), heating rate (10 K/min) and carbon-containing precursor preparation temperature (473 K), the prepared porous carbon material has the largest specific surface area of 1703 m2/g, relatively high micropore volume of 0.51 cm3/g and microporosity of 24.17%. The hydrogen adsorption capacity of the carbon material can reach 170.12 cm3/g (1.53 wt%) at 77 K at atmospheric pressure. This paper provides a novel and environmental-friendly method for the preparation of porous carbon materials, and also presents a new way for the utilization of biomass pyrolysis vapors before condensation.

PH-dependent chloride desorption isotherms of Portland cement paste

Carbonation, sulfate, and acid attack can lead to the release of bound chlorides, increasing the concentration of free chlorides in concrete pore solutions. The objective of this study was to develop pH-dependent chloride desorption isotherms for OPC paste exposed to MgCl2, CaCl2, and NaCl solutions. This study showed that the Langmuir isotherm suits the chloride binding of ground OPC paste the best, and the amount of bound chloride is predominantly influenced by the cation-type of chloride in the decreasing order CaCl2 > MgCl2 > NaCl. The results of the thermogravimetric analysis also confirmed this. The mass loss of Friedel's salt apparent in DTG curves indicated that more chlorides from CaCl2 salt may bind with cement hydrates. The phase assemblages predicted by thermodynamic modeling were found to be in good agreement with the experimental results. The drop in the pH of the exposure solution, achieved by adding nitric acid to the exposure solution, initially resulted in the total dissociation of the bound chlorides from the MgCl2 and NaCl salts. However, only 58% of the bound chlorides from the CaCl2 solution could be dissociated as a result of the reduced pH of the exposure solution. Moreover, the dissociation of bound chlorides resulted in the removal of Friedel's salt and the formation of calcium nitrate. The further addition of nitric acid resulted in the formation of a calcium-rich hydrogel capable of absorbing free chlorides.

Determination of Thermodynamic Parameters of Polylactic Acid by Thermogravimetry under Pyrolysis Conditions

In the present study, the thermodynamic parameters of Polylactic Acid (PLA) under conditions of thermal degradation were determined. The PLA material, previously sampled and characterized, was analyzed by dynamic thermogravimetry (TG) at heating rates of 5, 10 and 15 °C min−1 with a nitrogen flow of 20 mL min−1 from a temperature of 25 to 900 °C. The data were treated using isoconversional kinetic models to obtain the activation energy and the pre-exponential factor of each model. To fit the DTG curves, the Arrhenius equation was used applying the Contraction Sphere reaction model: two-dimensional phase limit reaction (R2). The thermodynamic parameters such as enthalpy, Gibbs free energy and entropy were determined from the kinetic parameters of suitable models for each heating rate after statistical validation and comparison with other studies. The results showed that as the heating rate increases, the degradation temperature also increases, while the activation energy, enthalpy and pre-exponential factor decrease. According to the value of ∆G (171.65 kJ mol−1), PLA has a significant potential to be used as a raw material to produce bioenergy/biofuels by pyrolysis.

Food Xanthan Polysaccharide Sulfation Process with Sulfamic Acid.

Xanthan is an important polysaccharide with many beneficial properties. Sulfated xanthan derivatives have anticoagulant and antithrombotic activity. This work proposes a new method for the synthesis of xanthan sulfates using sulfamic acid. Various N-substituted ureas have been investigated as process activators. It was found that urea has the greatest activating ability. BBD of xanthan sulfation process with sulfamic acid in 1,4-dioxane has been carried out. It was shown that the optimal conditions for the sulfation of xanthan (13.1 wt% sulfur content) are: the amount of sulfating complex per 1 g of xanthan is 3.5 mmol, temperature 90 °C, duration 2.3 h. Sulfated xanthan with the maximum sulfur content was analyzed by physicochemical methods. Thus, in the FTIR spectrum of xanthan sulfate, in comparison with the initial xanthanum, absorption bands appear at 1247 cm−1, which corresponds to the vibrations of the sulfate group. It was shown by GPC chromatography that the starting xanthan gum has a bimodal molecular weight distribution of particles, including a high molecular weight fraction with Mw > 1000 kDa and an LMW fraction with Mw < 600 kDa. It was found that the Mw of sulfated xanthan gum has a lower value (~612 kDa) in comparison with the original xanthan gum, and a narrower molecular weight distribution and is characterized by lower PD values. It was shown by thermal analysis that the main decomposition of xanthan sulfate, in contrast to the initial xanthan, occurs in two stages. The DTG curve has two pronounced peaks, with maxima at 226 and 286 °C.

Study on the thermogravimetric and combustion of coal slime

ABSTRACT The study of the combustion characteristics of single-particle solid fuels is the basis for achieving clean combustion of solid fuels, coal slime is currently a relatively common waste solid fuel. This work uses a thermogravimetric analyzer to study the heat release and weight loss process of coal slime with different ash contents under different heating rates. Through the analysis of TG and DTG curves, the combustion characteristic parameters of slime are solved. The results show that under the same heating rate condition, as the ash content of coal slime increases, the TG and DTG curves move to the higher temperature area, the peak value of the DTG curve gradually decreases, the ignition temperature first decreases and then increases, and the ignition delay time slightly decreases, the flammability index decreases, the ignition stability characteristic first increases and then decreases, and the burnout characteristic index first decreases and then increases. The coal slime sample with 50% ash content has the best ignition stability characteristics. The 50A sample has the highest ignition stability characteristic index, which is 2.47, 2.37, and 2.26 at heating rates of 20 K/min, 30 K/min, and 50 K/min, respectively.

Thermogravimetric Analysis of the Combustion of Khakassia Coal, Pine Sawdust and their Blends

A thermogravimetric analysis (TGA) of the combustion of two long-flame hard coals from the Republic of Khakassia, pine sawdust and their blends in the air stream, depending on the chemical composition and thermal characteristics of the samples, was carried out. The ignition temperature and the burn-out temperature of the coke residue of the studied samples were determined by extrapolation using the TG and DTG curves. The indices of ignition, burnout and combustion are calculated taking into account the time parameters. The ignition temperature of pine sawdust was Ti = 308 °C, the burnout temperature was Tb = 490 °C. When sawdust was added to the coals, the combustion process of the blend shifted to lower temperatures, and the ignition temperature decreased by more than 100 °C compared to the ignition temperature of the coals. The energy -efficient compositions of blends that ensure their high combustion characteristics are determined

Experimental investigation on microstructure evolution and spontaneous combustion properties of aerobic heated coal

Since coal oxidation and heat accumulation are prerequisites for coal spontaneous combustion, it is of great significance to study the characteristics of coal oxidation and heat accumulation to grasp characteristics of spontaneous combustion of residual coal and to locate the area with coal spontaneous combustion in goaf. In this study, three types of lignite and bituminous coal with a strong spontaneous combustion tendency were selected to prepare raw coal samples and aerobic heated coal samples. Then ultimate and proximate test, core pore and surface area test, SEM test, TG test, FTIR test and temperature-programmed test were undertaken, respectively. After coal undergoes aerobic heated progress, its surface micro-cracks, internal pore volume and specific surface area surge, and the active functional groups vary significantly; the contents of C and H fall, and that of O rises. These changes are conducive to coal oxidation. The temperatures corresponding to the first peak points in the DTG curves for the aerobic heated coal samples are lower than those for the raw coal samples, which indicates that the aerobic heated coal samples enter the self-oxidation acceleration stage earlier. Besides, according to the results of the temperature-programmed experiment, the cross-point temperatures of CO generation for the aerobic heated coal samples and the raw coal samples are 91 °C, 82 °C and 76 °C, respectively. A comprehensive analysis discloses that the aerobic heated coal samples are more likely to combust spontaneously in the initial stage of oxidation and to generate more CO. The heat dissipation zone, oxidation zone and suffocation zone were divided by monitoring the oxygen concentration changes in goaf at different stages on 5–20101 working face. It is determined that the oxidation zone of the goaf is 71–152 m on the inlet side and 59–128 m on the return side.

Influence of γ-radiation on thermal destruction of a cross-linked acrylic polymer

The effect of γ-radiation dosage on the thermal stability of the cross-linked acrylic polymer "Carbomer-140" (СRB) was investigated. The DTA, TGA, and DTG curves show multistage processes occurring in different temperature ranges on heating CRB from 25 °C to 500 °C. The rates of thermal decomposition of CRB were determined in the temperature ranges of 40–110 °C, 180–260 °C, 260–330 °C, and 330–500 °C. In combination with results of electronic structure calculations, potential thermal destruction reactions were proposed for the indicated temperature ranges. The main reactions for thermal decomposition of CRB are formation of ketones and cyclic anhydrides with formation of unsaturated bonds in the macromolecule due to elimination of H2O, CO2, and CO, respectively, from the polymer chain. An increase in the radiation dose applied to CRB leads to a decrease in the post-radiation thermal stability of the polymer. During radiolysis, double bonds are formed and accumulate in the polymer, contributing to the thermal destruction of CRB. As a result, the higher the radiation dose, the higher the rate of post-radiation thermal destruction.

Energy optimization from a binary mixture of non-edible oilseeds pyrolysis: Kinetic triplets analysis using Thermogravimetric Analyser and prediction modeling by Artificial Neural Network

Pyrolysis kinetics and thermodynamic parameters of two non-edible seeds, Pongamia pinnata (PP) and Sapindus emarginatus (SE), and their blend in the ratio of 1:1 (PS) were studied using the thermogravimetric analyzer. Kinetic triplets were determined using both model-free [Starink (STR), Friedman (FRM), Iterative Kissinger-Akahira-Sunose (IT-KAS), Iterative Ozawa-Flynn-Wall (IT-OFW), Vyazovkin (VYZ), and Master plot (MP)] and model fitting Coats-Redfern (CR) methods at three different heating rates 10, 30 and 50 °C/min. Activation energies were 192.66, 179.44, and 163.25 kJ/mol for PP, SE, and PS, respectively. It was found that the blend of the two-biomass (PS) showed promising results with lower activation energy compared to the individual biomass. Thermodynamic parameters (ΔG, ΔS, and ΔH) were obtained using the model-free isoconversional method. The three hidden layers of complex neuron topology are well fitted to the experimental DTG curves by artificial neural network (ANN). The study confirmed that the heating rate had a significant impact on the kinetics and thermodynamic parameters. The reaction mechanism was also in consonance with the experimental data. The study suggests that the PP and SE seeds can be an appropriate feed for pyrolysis, and their blend (PS) can be a viable alternative in optimizing the entire process.

Insight in the Crystallization Kinetics of AlPO4-11 Molecular Sieve Using Di-Isopropylamine as Template

The hydrothermal synthesis of aluminophosphate molecular sieve type AlPO4-11 was processed from chemicals containing psueudobohemite, 85% phosphoric acid, water, and di-isopropylamine as templating agent. The crystallization of the samples was studied by taking samples in times from 2 to 74 h. The obtained white powder products were characterized by X-ray diffraction patterns (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetry (TG) and differential scanning calorimetry (DTG) data and pH measurement of the mother liquor. The pore volume, as determined from TG and DTG curves, was ca. 0.17 cm3g−1. The percent relative crystallinity was determined by XRD and FT-IR methods. The crystallization kinetics evidenced that the hydrothermal synthesis of AlPO4-11 exhibited in its initial phase a behavior of first order reaction with a specific velocity constant of ca. 0.25 h−1, as determined from XRD and FT-IR data. The results obtained by both X-ray diffraction and infrared spectroscopy are comparable, and FT-IR is found to be a rapid method for estimating crystallinity and structure of aluminophosphate.

Pyrolysis Characteristics and Kinetics Analysis of Oil Sludge with CaO Additive

In the process of exploitation, transportation and refining of high-sulfur crude oil, a large number of oil sludge (OS) with high sulfur content is produced. Pyrolysis has been proved to be an effective method for OS disposal, but for solid waste with high sulfur content, lots of sulfur-containing gases will be released during thermal disposal. The addition of calcium oxide [1] in pyrolysis process is an economical and effective way to capture sulfur-containing gases. In order to understand the pyrolysis process of OS with CaO, a thermogravimetric analyzer was used to conduct pyrolysis experiments of OS with different Ca/S molar ratios (0, 1, 2, and 3) at different heating rates (10, 20, 30 and 40 °C/min). The results showed that with the increase of CaO addition the derivative thermogravimetric curves (DTG curves) showed a gentle trend. In addition, new weight loss peaks were occurred at 700∼900°C and after 1100°C, which were the decomposition of calcium carbonate and calcium sulfate, respectively. The kinetic parameters were solved by Friedman, FWO, and Starink methods, and the results were similar, with an average activation energies (E) value of 214 kJ/mol. The change trend of the activation energy followed by an increase and then a decrease corresponding to the change of energy demand for the reaction. The calculated average values of ΔH, ΔG and ΔS were about 207 kJ/mol, 447 kJ/mol and -0.3250 kJ/mol respectively. When the conversion rate was 0.5, the thermodynamic parameters reached their maximum values.