Maximum heating rates for producing undistorted glassy carbon ware determined by wedge-shaped samples

Polymeric carbon artifacts are particularly difficult to make in thick section. Heating rate, temperature, and sample thickness determine the outcome of carbonization of resin leading to a glassy polymeric carbon ware. Using wedge-shaped samples, we found the maximum thickness for various heating rates during gelling (300 K–360 K), curing (360 K–400 K), postcuring (400 K–500 K), and precarbonization (500 K–875 K). Excessive heating rate causes failure. In postcuring the critical heating rate varies inversely as the fifth power of thickness; in precarbonization this varies inversely as the third power of thickness. From thermogravimetric evidence we attribute such failure to low rates of diffusion of gaseous products of reactions occurring within the solid during pyrolysis. Mass spectrometry shows the main gaseous product is water vapor; some carboniferous gases are also evolved during precarbonization. We discuss a diffusion model applicable to any heat-treatment process in which volatile products are removed from solid bodies.

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Py–FTIR–GC/MS Analysis of Volatile Products of Automobile Shredder Residue Pyrolysis

Polymers ◽

10.3390/polym12112734 ◽

2020 ◽

Vol 12 (11) ◽

pp. 2734

Author(s):

Bin Yang ◽

Ming Chen

Keyword(s):

Alternative Energy ◽

Oil And Gas ◽

Gaseous Product ◽

Steam Gasification ◽

Pyrolysis Oil ◽

Shredder Residue ◽

Gaseous Products ◽

Automobile Shredder Residue ◽

Ms Analysis ◽

Volatile Products

Automobile shredder residue (ASR) pyrolysis produces solid, liquid, and gaseous products, particularly pyrolysis oil and gas, which could be used as renewable alternative energy resources. Due to the primary pyrolysis reaction not being complete, the yield of gaseous product is low. The pyrolysis tar comprises chemically unstable volatiles before condensing into liquid. Understanding the characteristics of volatile products will aid the design and improvement of subsequent processes. In order to accurately analyze the chemical characteristics and yields of volatile products of ASR primary pyrolysis, TG–FTIR–GC/MS analysis technology was used. According to the analysis results of the Gram–Schmidt profiles, the 3D stack plots, and GC/MS chromatograms of MixASR, ASR, and its main components, the major pyrolytic products of ASR included alkanes, olefins, and alcohols, and both had dense and indistinguishable weak peaks in the wavenumber range of 1900–1400 cm−1. Many of these products have unstable or weaker chemical bonds, such as =CH–, =CH2, –C=C–, and –C=CH2. Hence, more syngas with higher heating values can be obtained with further catalytic pyrolysis gasification, steam gasification, or higher temperature pyrolysis.

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Pyrolysis and Oxidation of PAN in Dry Air. Thermoanalytical Methods

Materials Science ◽

10.5755/j01.ms.17.1.246 ◽

1970 ◽

Vol 17 (1) ◽

pp. 38-42

Author(s):

Anna BIEDUNKIEWICZ ◽

Pawel FIGIEL ◽

Marta SABARA

Keyword(s):

Temperature Increase ◽

Heating Rates ◽

Linear Change ◽

Dry Air ◽

Isothermal Conditions ◽

Gaseous Products ◽

Heterogeneous Processes ◽

Temperature Ranges ◽

Higher Temperature ◽

Kinetics Of

The results of investigations on pyrolysis and oxidation of pure polyacrylonitrile (PAN) and its mixture with N,N-dimethylformamide (DMF) under non-isothermal conditions at linear change of samples temperature in time are presented. In each case process proceeded in different way. During pyrolysis of pure PAN the material containing mainly the product after PAN cyclization was obtained, while pyrolysis of PAN+DMF mixture gave the product after cyclization and stabilization. Under conditions of measurements, in both temperature ranges, series of gaseous products were formed.For the PAN-DMF system measurements at different samples heating rates were performed. The obtained results were in accordance with the kinetics of heterogeneous processes theory. The process rates in stages increased along with the temperature increase, and TG, DTG and HF function curves were shifted into higher temperature range. This means that the process of pyrolysis and oxidation of PAN in dry air can be carried out in a controlled way.http://dx.doi.org/10.5755/j01.ms.17.1.246

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Towards a better representation of the solar cycle in general circulation models

Atmospheric Chemistry and Physics ◽

10.5194/acp-7-5391-2007 ◽

2007 ◽

Vol 7 (20) ◽

pp. 5391-5400 ◽

Cited By ~ 59

Author(s):

K. M. Nissen ◽

K. Matthes ◽

U. Langematz ◽

B. Mayer

Keyword(s):

Solar Cycle ◽

Heating Rate ◽

General Circulation ◽

Temperature Response ◽

General Circulation Models ◽

Short Wave ◽

Radiative Transfer Model ◽

Transfer Model ◽

Heating Rates ◽

Radiation Scheme

Abstract. We introduce the improved Freie Universität Berlin (FUB) high-resolution radiation scheme FUBRad and compare it to the 4-band standard ECHAM5 SW radiation scheme of Fouquart and Bonnel (FB). Both schemes are validated against the detailed radiative transfer model libRadtran. FUBRad produces realistic heating rate variations during the solar cycle. The SW heating rate response with the FB scheme is about 20 times smaller than with FUBRad and cannot produce the observed temperature signal. A reduction of the spectral resolution to 6 bands for solar irradiance and ozone absorption cross sections leads to a degradation (reduction) of the solar SW heating rate signal by about 20%. The simulated temperature response agrees qualitatively well with observations in the summer upper stratosphere and mesosphere where irradiance variations dominate the signal. Comparison of the total short-wave heating rates under solar minimum conditions shows good agreement between FUBRad, FB and libRadtran up to the middle mesosphere (60–70 km) indicating that both parameterizations are well suited for climate integrations that do not take solar variability into account. The FUBRad scheme has been implemented as a sub-submodel of the Modular Earth Submodel System (MESSy).

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INVESTIGATION OF THERMAL DEGRADATION OF POULTRY PROCESSING DEWATERED SLUDGE USING THERMOGRAVIMETRIC ANALYSIS METHOD

Jurnal Teknologi ◽

10.11113/jt.v76.5522 ◽

2015 ◽

Vol 76 (5) ◽

Author(s):

N. Aniza ◽

S. Hassan ◽

M. F. M. Nor ◽

K. E. Kee ◽

Aklilu T.

Keyword(s):

Particle Size ◽

Thermogravimetric Analysis ◽

Thermal Degradation ◽

Heating Rate ◽

Degradation Process ◽

Heating Rates ◽

Initial Stage ◽

Poultry Processing ◽

Effect Of Particle Size ◽

Dewatered Sludge

Thermal degradation of Poultry Processing Dewatered Sludge (PPDS) was studied using thermogravimetric analysis (TGA) method. The effect of particle size on PPDS samples and operational condition such as heating rates were investigated. The non-isothermal TGA was run under a constant flow of oxygen at a rate of 30 mL/min with temperature ranging from 30ºC to 800ºC. Four sample particle sizes ranging between 0.425 mm to 2 mm, and heating rate between 5 K/min to 20 K/min were used in this study. The TGA results showed that particle size does not have any significant effect on the thermogravimetry (TG) curves at the initial stage, but the TG curves started to separate explicitly at the second stage. Particle size may affect the reactivity of sample and combustion performance due to the heat transfer and temperature gradient. The TG and peak of derivative thermogravimetry (DTG) curves tend to alter at high temperature when heating rate is increased most likely due to the limitation of mass transfer and the delay of degradation process.

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Kinetics study on non-isothermal thermochemical liquefaction of corncobs in ethanol-water solution: Effect of ethanol concentration

MATEC Web of Conferences ◽

10.1051/matecconf/201819709005 ◽

2018 ◽

Vol 197 ◽

pp. 09005

Author(s):

Bregas Siswahjono Tatag Sembodo ◽

Hary Sulistyo ◽

Wahyudi Budi Sediawan ◽

Mohammad Fahrurrozi

Keyword(s):

Experimental Data ◽

Kinetic Models ◽

Ethanol Concentration ◽

Water Solution ◽

Reaction Products ◽

Gaseous Products ◽

Bio Oil ◽

Volatile Products ◽

Calculation Results ◽

Oil Gas

Corncobs are potentially processed into bio-oil through thermochemical liquefaction processes. It is difficult to construct kinetics models based on the compounds involved in the reaction. It would be made four kinetic models based on four reaction products, i.e., solids, bio-oil, gas and volatile products. The purposes of the study were to seek kinetics model of thermochemical liquefaction of corncobs in ethanol-water solution and to study the effect of ethanol concentration. The experiment of liquefaction processes of corncobs in ethanol-water solution using sodium carbonate catalyst was performed in the 150 ml autoclave equipped with a magnetic stirrer in the temperature up to 280°C. Four kinetic models were applied to predict the yield of four reaction product lumps. The calculation results were compared to the experimental data. Compared to the others, model 4 was the most realistic and closely matching to the experimental data. In model 4 the reaction mechanism was assumed that biomass (corncobs) first decomposed into bio-oil, followed by decomposition of bio-oil into volatile products reversibly and, finally, volatile products decomposed into gaseous products. The yield of bio-oil increased from 42.05% to 54.93% by increasing to ethanol concentration of 0% to 40%.

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Effect of heating rates on the microstructure and gas permeation properties of carbon membranes

Malaysian Journal of Fundamental and Applied Sciences ◽

10.11113/mjfas.v14n3.1024 ◽

2018 ◽

Vol 14 (3) ◽

pp. 378-381

Author(s):

Norazlianie Sazali ◽

Wan Norharyati Wan Salleh ◽

Ahmad Fauzi Ismail ◽

Kumaran Kadirgama ◽

Mohamad Shahrizan Moslan ◽

...

Keyword(s):

Heating Rate ◽

High Performance ◽

Room Temperature ◽

Gas Permeation ◽

Carbon Membrane ◽

Heating Rates ◽

Polymer Blending ◽

Carbon Membranes ◽

Permeation Properties ◽

Fine Turning

High performance tubular carbon membrane (TCM’s) for CO2 separation were prepared by controlling the carbonization heating rates in range of 1-7 oC/min carbonized at 800 oC under Argon environment. A single permeation apparatus was used to determine the gas permeation properties of the membrane at room temperature. Fine turning of the carbonization condition was necessary to obtain the desired permeation properties. The preparation of PI/NCC-based TCM at low heating rate caused the gas permeance for the examined gas N2 and CO2 decreased whereas the selectivity of CO2/N2 increased. It was also identified that the gas permeation properties of the resultant TCM and its structure was highly affected by the heating rate. The best carbonization heating rate was found at 3oC/min for the fabrication of TCM derived via polymer blending of PI/NCC for CO2/N2 separation.

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Synthesis and characterization of a new conjugated polymer containing bithiazole group and its thermal decomposition kinetics

Macedonian Journal of Chemistry and Chemical Engineering ◽

10.20450/mjcce.2020.2025 ◽

2020 ◽

Vol 39 (2) ◽

pp. 227

Author(s):

Adnan Kurt ◽

Hacer Andan ◽

Murat Koca

Keyword(s):

Thermal Decomposition ◽

Heating Rate ◽

Conjugated Polymer ◽

Three Dimensional ◽

Heating Rates ◽

Diffusion Type ◽

Optimum Heating ◽

Rate Loss ◽

Kinetics Of

A new conjugated polymer containing a bithiazole group is prepared by the polycondensation of 2,2'-diamino-4,4'-bithiazole and terephthaldialdehyde in the presence of glacial acetic acid. The kinetics of thermal degradation of the new polymer are investigated by thermogravimetric analysis at different heating rates. The temperature corresponding to the maximum rate loss shifts to higher temperatures with increasing heating rate. The thermal decomposition activation energies of the conjugated polymer in a conversion range of 3–15 % are 288.4 and 281.1 kJ/mol by the Flynn–Wall–Ozawa and Kissinger methods, respectively. The Horowitz–Metzger method shows that the thermodegradation mechanism of the conjugated polymer proceeds over a three-dimensional diffusion type deceleration D3 mechanism. The optimum heating rate is 20 ºC/min.

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Investigation of Primary Recrystallization and Decarbonization with Different Heating Rates of Intermediate Annealing Using Nb-Containing Grain-Oriented Silicon Steel

Metals ◽

10.3390/met11101655 ◽

2021 ◽

Vol 11 (10) ◽

pp. 1655

Author(s):

Xin Tian ◽

Shuang Kuang ◽

Jie Li ◽

Jing Guo ◽

Yunli Feng

Keyword(s):

Heating Rate ◽

Electron Backscatter Diffraction ◽

Optical Microscope ◽

Primary Recrystallization ◽

Silicon Steel ◽

Intermediate Annealing ◽

Heating Rates ◽

Average Grain Size ◽

The Matrix ◽

20 Nm

An Nb-containing grain-oriented silicon steel was produced through double-stage cold rolling in order to investigate the effect of the heating rate during intermediate annealing on primary recrystallization and decarburization behavior. The microstructure and texture were observed and analyzed by an optical microscope and an electron backscatter diffraction system. A transmission electron microscope was used to observe the precipitation behavior of inhibitors. The decarburization effect during intermediate annealing was also calculated and discussed. The results show that primary recrystallization takes place after intermediate annealing. As the heating rate increases, the average grain size decreases gradually. The textures of {411}<148> and {111}<112> were found to be the strongest along the thickness direction in all of the annealed specimens and are mainly surrounded by HEGB and HAGB (> 45°). A large number of inhibitors with the size of 14~20 nm precipitate are distributed evenly in the matrix. The above results indicate that the higher heating rate during intermediate annealing contributes to both an excellent microstructure and magnetic properties. From the calculation, as the heating rate increases, decarbonization tends to proceed in the insulation stage, and the total amount of carbonization declines.

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Volatile Products From Pyrolysis of Cotton Fabrics Finished With Thps-Urea-Phosphate

Journal of Fire Sciences ◽

10.1177/073490418300100303 ◽

1983 ◽

Vol 1 (3) ◽

pp. 165-176 ◽

Cited By ~ 3

Author(s):

William E. Franklin

Keyword(s):

Mass Spectrometry ◽

Carbon Dioxide ◽

Flame Retardant ◽

Cotton Fabrics ◽

Pyrolysis Mass Spectrometry ◽

Mole Percent ◽

Pyrolysis Products ◽

Urea Phosphate ◽

Volatile Products ◽

Water Fractions

Volatile products evolved during the pyrolysis of cotton fabrics treated with various add-ons of THPS-urea-phosphate flame retardant were measured by pyrolysis-mass spectrometry. Molar fractions of nine primary, volatile pyrolysis products were determined, accounting for 82-89 mole percent of the products. Three classes of volatile products were distinguished on the basis of the response of the product fractions to add-on of the flame retardant. Increasing add-on decreased the anhydroglucose fractions. Small add-ons increased the "furan" fractions and large add-ons decreased them. Nonfuel fractions increased with increasing add-on. Inverse relations were found between anhydroglucose fractions and water fractions and between "furan" fractions and carbon dioxide fractions. The flame retardancy of the cotton fabrics had the best correlation with the water fractions. These results are compared and contrasted with data from the pyrolysis of cotton fabrics treated with another flame retardant, THPOH-ammonia.

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Heat Transfer Technology to Convert Plastic Trash to Oil

Volume 8: Heat Transfer and Thermal Engineering ◽

10.1115/imece2017-70953 ◽

2017 ◽

Cited By ~ 1

Author(s):

Mahmoud Elsharafi ◽

Cody Chancellor ◽

Cameron Duckworth ◽

Moiz Tatla ◽

Reuben Denwe ◽

...

Keyword(s):

Heat Transfer ◽

Feedback Loop ◽

Modern Society ◽

Environmental Issue ◽

Heating Rates ◽

Waste Plastic ◽

Control Temperature ◽

The Road ◽

Gaseous Products ◽

Plastic Type

In modern society, plastic waste has become a serious environmental issue. The inability of most hydrocarbon based plastics to naturally decompose quickly causes concern. The material piles up in landfills, waterways, and along the side of the road. One way to combat this issue is the repurposing of the material. Plastic can be converted back into oil (called pyrolysis) and refined to produce fuels. To attempt this, a custom-built steel reactor is to be filled with waste plastic, and will be heated to the plastic’s boiling point in an inert (N2) environment. The resulting vapor will be recondensed in a specially designed heat exchanger, resulting in oil, wax, and gaseous byproducts. The oil and waxes are collected in one container, and the gases are collected in a separate container. The system will require the use of thermocouples and a feedback loop to properly control temperature. The results are expected to show a correlation between plastic type and resulting byproduct composition with Grade 1 plastics producing the most gas. In addition, faster heating rates, larger plastic particle size, and higher temperatures should increase gaseous products. This may aid in the creation of commercial/industrial sized pyrolysis systems.

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