Study of the Kinetics of Thermal Destruction of Crossed Polyethylene

2019 ◽  
Vol 5 (12) ◽  
pp. 37-46
Author(s):  
K. Chalov ◽  
Yu. Lugovoy ◽  
Yu. Kosivtsov ◽  
E. Sulman
Keyword(s):  
Total Yield ◽  
Calorific Value ◽  
High Heat ◽  
Process Temperature ◽  
Optimum Process ◽  
Quantitative Composition ◽  
Pyrolysis Gas ◽  
Gaseous Products ◽  
Liquid Products ◽  
Kinetics Of

This paper presents a study of the process of thermal degradation of crosslinked polyethylene. The kinetics of polymer decomposition was studied by thermogravimetry. Crosslinked polyethylene showed high heat resistance to temperatures of 400 °C. The temperature range of 430–500 °C was determined for the loss of the bulk of the sample. According to thermogravimetric data, the decomposition process proceeds in a single stage and includes a large number of fracture, cyclization, dehydrogenation, and other reactions. The process of pyrolysis of a crosslinked polymer in a stationary-bed metal reactor was investigated. The influence of the process temperature on the yield of solid, liquid, and gaseous pyrolysis products was investigated. The optimum process temperature was 500 °C. At this temperature, the yield of liquid and gaseous products was 85.0 and 12.5% (mass.), Respectively. Samples of crosslinked polyester decomposed almost completely. The amount of carbon–containing residue was 3.5% by weight of the feedstock. With increasing temperature, the yield of liquid products decreased slightly and the yield of gaseous products increased, but their total yield did not increase. For gaseous products, a qualitative and quantitative composition was determined. The main components of the pyrolysis gas were hydrocarbons C1–C4. The calorific value of pyrolysis gas obtained at a temperature of 500 °C was 17 MJ/m3. Thus, the pyrolysis process can be used to process crosslinked polyethylene wastes to produce liquid hydrocarbons and combustible gases.

scholarly journals ВЛИЯНИЕ ТЕХНОЛОГИЧЕСКОГО РЕЖИМА УСТАНОВКИ ТЕРМИЧЕСКОГО ПИРОЛИЗА УГЛЕВОДОРОДОВ НА КАЧЕСТВЕННЫЙ СОСТАВ ТЯЖЁЛОЙ СМОЛЫ

World Science ◽  
2019 ◽  
Vol 1 (1(41)) ◽  
pp. 29-35
Author(s):  
Садыгов Ф. М. ◽  
Магеррамова З. Ю. ◽  
Гаджиев Г. Н. ◽  
Гасан-заде Г. Г. ◽  
Мамедова И. Г. ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Maximum Yield ◽  
Optimum Process ◽  
Quantitative Composition ◽  
Process Conditions ◽  
Low Molecular Weight ◽  
Technological Parameters ◽  
Alkyl Derivatives ◽  
Liquid Products ◽  
Heavy Pyrolysis Resin

The dependence of the yield and composition of the heavy pyrolysis resin on the initial hydrocarbon feedstock and the process conditions is investigated. The variation of technological parameters within certain limits leads to a change in the content of low molecular weight olefins in the gaseous pyrolysis products, as well as the qualitative and quantitative composition of by-product liquid products. As a result of the research, the optimum process conditions for the pyrolysis of straight-run gasoline were determined, which, with the maximum conversion of hydrocarbons to low-molecular-weight olefins, significantly increases the yield of heavy resin containing a wide fraction of naphthalene, biphenyl, indene and their alkyl derivatives. It is shown that when treating by-products containing valuable hydrocarbons as target products and combining the technological mode of pyrolysis and their composition, it is possible to achieve along with the maximum yield of low molecular weight olefins, a significant yield of heavy pyrolysis resin and qualitative changes in its composition.

Kinetics of temperature-programmed reactivation of a hydrodesulphurization catalyst

1983 ◽  
Vol 48 (12) ◽  
pp. 3340-3355 ◽  
Author(s):  
Pavel Fott ◽  
Pavel Šebesta
Keyword(s):  
Carbon Dioxide ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Thin Layer ◽  
Kinetic Parameters ◽  
Diffusion Region ◽  
Reaction Heat ◽  
Gaseous Products ◽  
Temperature Programmed ◽  
Kinetics Of

The kinetic parameters of reactivation of a carbonized hydrodesulphurization (HDS) catalyst by air were evaluated from combined thermogravimetric (TG) and differential thermal analysis (DTA) data. In addition, the gaseous products leaving a temperature-programmed reactor with a thin layer of catalyst were analyzed chromatographically. Two exothermic processes were found to take part in the reactivation, and their kinetics were described by 1st order equations. In the first process (180-400 °C), sulphur in Co and Mo sulphides is oxidized to sulphur dioxide; in the second process (300-540 °C), in which the essential portion of heat is produced, the deposited carbon is oxidized to give predominantly carbon dioxide. If the reaction heat is not removed efficiently enough, ignition of the catalyst takes place, which is associated with a transition to the diffusion region. The application of the obtained kinetic parameters to modelling a temperature-programmed reactivation is illustrated on the case of a single particle.

scholarly journals Pyrolysis and Oxidation of PAN in Dry Air. Thermoanalytical Methods

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

Effects of Zn on Pyrolysis Characteristics of Shenhua Lignite

2014 ◽  
Vol 1008-1009 ◽  
pp. 247-251
Author(s):  
Wipawan Sangsanga ◽  
Chuan Na ◽  
Jin Xiao Dou ◽  
Jiang Long Yu
Keyword(s):  
Pyrolysis Temperature ◽  
Fixed Bed ◽  
Coal Pyrolysis ◽  
Pyrolysis Gas ◽  
Gaseous Products ◽  
Pyrolysis Characteristics ◽  
Maximum Value ◽  
Product Gas ◽  
Zn Content ◽  
Catalytic Effects

The catalytic effects of Zn on the release of the gaseous products during pyrolysis of Shenhua lignite was investigated by using a fixed-bed quartz reactor. The product gas compositions from the coal pyrolysis were analyzed by a gas chromatography (GC). Experimental results show that Zn had noticeable catalytic effects on lignite pyrolysis. With the increase in Zn content, lignite weight loss increases during pyrolysis. However, there was an optimum content for amount Zn into the coal. Pyrolysis temperature had a great impact on the composition of pyrolysis gas. As the pyrolysis temperature increased, char yield decreased and gas yield increased. There existed a temperature that tar yield reached its maximum value.

scholarly journals Fractionation of Birch Wood by Integrating Alkaline-Acid Treatments and Hydrogenation in Ethanol over a Bifunctional Ruthenium Catalyst

Catalysts ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1362
Author(s):  
Boris N. Kuznetsov ◽  
Sergey V. Baryshnikov ◽  
Angelina V. Miroshnikova ◽  
Aleksandr S. Kazachenko ◽  
Yuriy N. Malyar ◽  
...  
Keyword(s):  
Microcrystalline Cellulose ◽  
Catalytic Hydrogenation ◽  
Liquid Product ◽  
Gel Permeation Chromatography ◽  
Ruthenium Catalyst ◽  
Birch Wood ◽  
Gaseous Products ◽  
Liquid Products ◽  
First Time

For the first time, the fractionation of birch wood into microcrystalline cellulose, xylose and methoxyphenols is suggested based on the integration of alkali-acid pretreatments and hydrogenation in ethanol over a bifunctional Ru/C catalyst. It is established that removal of hemicelluloses during pretreatments of birch wood influences the yields of the liquid, gaseous and solid products of the non-catalytic and catalytic hydrogenation of pretreated samples in ethanol at 225 °C. The bifunctional Ru/carbon catalyst affects in different ways the conversion and yields of products of hydrogenation of the initial and acid- and alkali-pretreated birch wood. The most noticeable influence is characteristic of the hydrogenation of the acid-pretreated wood, where in contrast to the non-catalytic hydrogenation, the wood conversion and the yields of liquid products increase but the yields of the solid and gaseous products decrease. GC-MS, gel permeation chromatography and elemental analysis were used for characterization of the liquid product composition. The molecular mass distribution of the liquid products of hydrogenation of the initial and pretreated wood shifts towards the low-molecular range in the presence of the catalyst. From the GC-MS data, the contents of monomer compounds, predominantly 4-propylsyringol and 4-propanolsyringol, increase in the presence of the ruthenium catalyst. The solid products of catalytic hydrogenation of the pretreated wood contain up to 95 wt% of cellulose with the structure, similar to that of microcrystalline cellulose.

scholarly journals The Effect of Carbonates and Silicates on the Cracking of a Mixture of Fuel Oil and Mechanically Activated Oil Shale

2021 ◽  
pp. 234-241
Author(s):  
Marina V. Mozhayskaya ◽  
Galina S. Pevneva ◽  
Vladimir G. Surkov
Keyword(s):  
Oil Shale ◽  
Fractional Composition ◽  
Fuel Oil ◽  
Gaseous Products ◽  
Liquid Products ◽  
Mineral Components ◽  
Diesel Fractions

The study cracking of a mixture of mechanically activated oil shale (MO OSh) and fuel oil, a mixture of demineralized MO GS and fuel oil has been investigated. The data on the composition of liquid products showed that after the removal of mineral components, oil shale is more easily destroyed due to the release of kerogen. It is shown that in the obtained liquid products of the cracking of the mixture of fuel oil – demineralized MO OSh, the proportion of oils increases to 74.6 % wt. In the composition of gaseous products of cracking, the amount of hydrogen, methane and ethane is noticeably reduced. According to the data on the fractional composition of liquid products, it was found that during the cracking of mixtures of fuel oil and MO HS, after the removal of carbonates and silicates, the proportion of gasoline and diesel fractions inc

Kinetics of ο-Chloronitrobenzene Hydrogenation on Palladium/Carbon Catalyst

2011 ◽  
Vol 239-242 ◽  
pp. 161-167
Author(s):  
Xiao Zhen Wang ◽  
Yi Feng Zhu ◽  
Xiao Nian Li
Keyword(s):  
High Selectivity ◽  
Total Yield ◽  
Hydrogenation Reaction ◽  
Commercial Application ◽  
Reaction Conditions ◽  
Solvent Free Conditions ◽  
Hydrogenation Kinetics ◽  
Favorable Reaction ◽  
Kinetics Of ◽  
Very High

A 2 wt % Pd/C catalyst has been prepared by chemical impregnation and used to catalyze the hydrogenation of o-chloronitrobenzene (o-CNB) to o-chloroaniline (o-CAN) in solvent-free conditions. The effects of reaction temperature, H2 pressure, and stirring intensity on the hydrogenation kinetics have been investigated. The hydrogenation reaction showed very high selectivity with dehalogenation side products as low as 0.3% of total yield. The favorable reaction conditions were found to be temperature T = 383 K, stirring speed = 900 rpm, and feeding ratio CNB/catalyst = 200/1 (m/m). The recycled Pd/C still retained more than 98% of its original selectivity after 12 repeat used, indicating the catalyst had strong potentials for commercial application at industrial scale.

Biomass Oxygen-Enriched Gasification in a Pressurized Fluidized Bed for Production of Middle/High Heat-Value Fuel Gas

2013 ◽  
Vol 860-863 ◽  
pp. 450-455 ◽  
Author(s):  
Qian Liu ◽  
Bao Sheng Jin
Keyword(s):  
Fluidized Bed ◽  
Calorific Value ◽  
High Heat ◽  
Operating Conditions ◽  
National Standards ◽  
Optimum Operating ◽  
Hydrocarbon Synthesis ◽  
Fuel Gas ◽  
Equivalent Ratio ◽  
Heat Value

For biomass gasification, the high tar and carbon monoxide contents and the low heat value of fuel gas are problems to be solved, which leading to the poor operating conditions of the completed projects in China. Therefore, a new technology of biomass oxygen-enriched gasification in pressurized fluidized bed is proposed. Coupling the technologies of pressurized biomass oxygen-enriched gasification at low temperature, high-temperature gasification and melting, steam reforming and hydrocarbon synthesis, the high gasification efficiency, tar cracking and gas reforming shall be realized, and the middle/high heat value gas which meets the national standards will be produced. ASPEN PLUS simulation was carried out for biomass oxygen-enriched gasification. Both the equivalent ratio and gas yield of rice husk are lower than that of the wood sawdust, while the gas calorific values are equivalent. Considering the gas yield, the calorific value and economy, the optimum operating conditions are obtained: the gasification temperature at 1200 °C, the oxygen purity at 0.9, the equivalent ratio at about 0.25, the S/B ratio at 0.1~0.2. The gas yield could reach 1.9 m3/kg, and the gas calorific value was above 11 MJ/m3.

scholarly journals Hydrothermal Carbonization Kinetics of Lignocellulosic Agro-Wastes: Experimental Data and Modeling

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 516 ◽  
Author(s):  
Michela Lucian ◽  
Maurizio Volpe ◽  
Luca Fiori
Keyword(s):  
Experimental Data ◽  
Reaction Kinetics ◽  
Reaction Pathway ◽  
Hydrothermal Carbonization ◽  
Kinetics Model ◽  
Transient Phase ◽  
Lumped Model ◽  
Gaseous Products ◽  
Best Fitting ◽  
Kinetics Of

Olive trimmings (OT) were used as feedstock for an in-depth experimental study on the reaction kinetics controlling hydrothermal carbonization (HTC). OT were hydrothermally carbonized for a residence time τ of up to 8 h at temperatures between 180 and 250 °C to systematically investigate the chemical and energy properties changes of hydrochars during HTC. Additional experiments at 120 and 150 °C at τ = 0 h were carried out to analyze the heat-up transient phase required to reach the HTC set-point temperature. Furthermore, an original HTC reaction kinetics model was developed. The HTC reaction pathway was described through a lumped model, in which biomass is converted into solid (distinguished between primary and secondary char), liquid, and gaseous products. The kinetics model, written in MATLABTM, was used in best fitting routines with HTC experimental data obtained using OT and two other agro-wastes previously tested: grape marc and Opuntia Ficus Indica. The HTC kinetics model effectively predicts carbon distribution among HTC products versus time with the thermal transient phase included; it represents an effective tool for R&D in the HTC field. Importantly, both modeling and experimental data suggest that already during the heat-up phase, biomass greatly carbonizes, in particular at the highest temperature tested of 250 °C.

Sign in / Sign up

Export Citation Format

Share Document