Bioenergy from Food Wastes: Thermal Decomposition of Carbohydrates, Lipids, and Proteins

2018 ◽  
Vol 61 (3) ◽  
pp. 797-805
Author(s):  
Zixu Yang ◽  
Jacob Collins ◽  
Ajay Kumar ◽  
Danielle Bellmer ◽  
Tim Bowser
Keyword(s):  
Activation Energy ◽  
Simple Structure ◽  
Reaction Scheme ◽  
Food Wastes ◽  
Model Compounds ◽  
Pyrolysis Products ◽  
Decomposition Scheme ◽  
Food Components ◽  
Protein Model ◽  
Single Reaction

Abstract. Food wastes differ in composition based on their sources and hence are difficult to use in gasification and pyrolysis technologies. The objectives of this study were to investigate the thermal devolatilization kinetics and pyrolysis products of three representative food components: lipids, carbohydrates, and protein. Devolatilization of carbohydrates and proteins occurred up to 600°C with a total weight loss of 90%. In particular, dextrose, sucrose, histidine, and phenylalanine exhibited a combined two-reaction decomposition scheme, whereas starch and valine exhibited a single-reaction scheme. Sucrose had a higher activation energy than dextrose as more energy was needed to cleave glyosidic linkages. Valine had the lowest activation energy (70.2 kJ mol-1) of all the protein model compounds due to its simple structure. However, the lipids primarily vaporized below 400°C and did not decompose. Pyrolysis products of carbohydrates were largely composed of furan and sugar-based compounds, whereas those of proteins varied depending on the type of protein. Because lipids mainly vaporized, only slight conversion (<1%) into different lipid types and hydrocarbons was observed. Keywords: Carbohydrate, Devolatilization, Food waste, Lipid, Protein, Py-GC/MS, Pyrolysis, Reaction kinetics, TGA.

The role of formaldehyde in the oxidation of ethylene

1952 ◽  
Vol 212 (1110) ◽  
pp. 291-311 ◽  
Keyword(s):  
Activation Energy ◽  
Ethylene Oxide ◽  
Induction Period ◽  
Maximum Rate ◽  
Reaction Scheme ◽  
Stationary Concentration ◽  
Rate Of Reaction ◽  
A Minor ◽  
Close Parallelism

The oxidation of ethylene at temperatures in the region of 400° C has been studied manometrically and analytically, and compared with the oxidation of formaldehyde under similar conditions. The observations of previous authors have been confirmed and extended with particular reference to the factors controlling the maximum rate of reaction. The oxidation of ethylene is closely dependent on the development of formaldehyde, which shows the behaviour to be expected of an agent for degenerate branching. There is a close parallelism between the variation of the activation energy of the oxidation of ethylene from 25 kcal at 350° C to 53 kcal at 550° C and of formaldehyde from 21 kcal at 350° C to more than 40 kcal at 500° C. Formaldehyde is produced in the oxidation of ethylene and attains a maximum concentration which is proportional to the ethylene pressure and independent of the oxygen pressure. The addition of formaldehyde to the reaction mixture reduces or removes the induction period without affecting the maximum rate of the reaction. Ethylene oxide plays a minor but significant part; it attains a stationary concentration in the reaction but is less effective than formaldehyde in reducing the induction period. A reaction scheme based on that proposed by Axford & Norrish (1948) for the oxidation of formaldehyde has been developed; it accounts satisfactorily for the observed facts.

scholarly journals Pyrolytic characteristics and kinetics of Guanzhong wheat straw and its components for high-value products

BioResources ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. 1958-1979
Author(s):  
Bingtao Hu ◽  
Zhaolin Gu ◽  
Junwei Su ◽  
Zhijian Li
Keyword(s):  
Activation Energy ◽  
Apparent Activation Energy ◽  
Wheat Straw ◽  
Pyrolysis Products ◽  
Transportation Fuels ◽  
Temperature Range ◽  
Model Free ◽  
System A ◽  
Gas Products ◽  
Kinetics Of

Wheat straw produced annually in the Shaanxi Guanzhong region is a potential biomass feedstock for the production of transportation fuels and specialized chemicals through combustion, pyrolysis, or gasification. In this work, the pyrolytic characteristics, evolved gas products, and kinetics of Guanzhong wheat straw and its components were first investigated with a thermogravimetry-Fourier infrared spectroscopy (TG-FTIR) system. A comparative kinetic study was conducted using different model-free methods of Flynn-Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS), Kissinger, and the Coats-Redfern methods. The main pyrolysis products identified by FTIR include H2O, CH4, CO2, and CO as well as aromatics, acids, ketones, and aldehydes. Kinetic results showed that the pyrolytic apparent activation energy of the straw is approximately 200 kJ/mol obtained via FWO and KAS methods at the conversion range of 0.4 to 0.75, which was 30 kJ/mol higher than the value 171.1 kJ/mol obtained by the Kissinger method. The apparent activation energy of cellulose in its main pyrolysis region is 135.5 kJ/mol and is about three times larger than that of hemicellulose (49.5 kJ/mol). The apparent activation energy of lignin at the temperature range of 45 to 116 °C was 34.5 kJ/mol, while that value at the temperature range of 120 to 252 °C was 6.64 kJ/mol.

Aufbau von Nonaphen-und Dithianonaphen-Derivaten - Modellverbindungen für gewinkelte Bandstrukturen / Generation of Nonaphene and Dithianonaphene Derivatives - Model Compounds for Bent Molecular Ribbons

1998 ◽  
Vol 53 (9) ◽  
pp. 1069-1073 ◽  
Author(s):  
Herbert Meier ◽  
Bernd Rose
Keyword(s):  
Reaction Scheme ◽  
Model Compounds ◽  
Related Reaction

The cycloaddition of the bisdienophile 1 and the benzo[c]furan generated in situ from the precursor 2 yielded the nonaphene derivative 4 (Scheme 1). A related reaction (Scheme 3) was used for the preparation of the dithianonaphene systems 6a, b, c, namely the [2π+8π] cycloaddition of 1 and 2H-benzothiete (5/5′). Acidic dehydration (aromatization) of 6a, b, c led to the dithianonaphenes 7a, b, c (Scheme 4).

Pyrolytic Behavior and Kinetic Analysis of Wheat Straw and Lignocellulosic Biomass Model Compound

2013 ◽  
Vol 860-863 ◽  
pp. 550-554 ◽  
Author(s):  
Zhi Qiang Wu ◽  
Shu Zhong Wang ◽  
Jun Zhao ◽  
Lin Chen ◽  
Hai Yu Meng
Keyword(s):  
Activation Energy ◽  
Kinetic Analysis ◽  
Wheat Straw ◽  
Lignocellulosic Biomass ◽  
Nitrogen Atmosphere ◽  
Thermochemical Conversion ◽  
Heating Rates ◽  
Decomposition Rates ◽  
Model Compounds ◽  
Pyrolysis Of Biomass

From a carbon cycle perspective, the thermochemical conversion of lignocellulosic biomass is inherently carbon neutral. Pyrolysis of biomass for energy supplying, such as bio-oil and bio-char, has been attracted much attention worldwide. Successful understanding the fundamental issues about the pyrolysis, including pyrolytic behavior and kinetic analysis of lignocellulosic biomass model compounds and real biomass, is essential for the further understanding and optimizing the pyrolysis process. In this paper, pyrolytic behavior of a typical lignocellulosic agricultural residue (wheat straw) and model compounds (cellulose) were measured through thermogravimetric analysis with various heating rates (10, 20, 40 °C·min-1) under nitrogen atmosphere. The results indicated that the interval of the weight loss for both wheat straw and cellulose moved upwards with the increment of heating rates. The maximum decomposition rates of cellulose were higher than those of wheat straw, and the temperature of maximum decomposition rates increased with the heating rates. Values of activation energy were solved through iso-conversional method. And the average values of activation energy for wheat straw and cellulose were 146.89 kJ·mol-1 and 134.56 kJ·mol-1 calculated from Flynn-Wall-Ozawa method, 144.05 kJ·mol-1 and 130.91 kJ·mol-1 calculated from Kissinger-Akahira-Sunose method, respectively.

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