scholarly journals Kinetics of Pyrolysis and Gasification Using Thermogravimetric and Thermovolumetric Analyses

2016 ◽  
Vol 62 (1) ◽  
pp. 17-25 ◽  
Author(s):  
Grzegorz Czerski ◽  
Katarzyna Zubek ◽  
Przemysław Grzywacz
Keyword(s):  
Conversion Degree ◽  
Solid Fuels ◽  
Carbon Conversion ◽  
Continuous Analysis ◽  
Gasification Process ◽  
Miscanthus Giganteus ◽  
Loss Of Weight ◽  
Kinetics Of ◽  
Carbon Dioxide Gasification

Abstract The carbon dioxide gasification process of Miscanthus giganteus biomass was examined using two methods. First an isothermal thermovolumetric method was applied. The measurement was conducted at 950°C and pressure of 0.1 MPa. Based on the continuous analysis of different kinds of gases formed during the gasification process, the thermovolumetric method allowed the determination of yields and composition of the resulting gas as well as the rate constant of CO formation. Then a non-isothermal thermogravimetric method was applied, during which the loss of weight of a sample as a function of temperature was recorded. In the course of the measurement, the temperature was raised from ambient to 950°C and the pressure was 0.1 MPa. As a result, a change in the carbon conversion degree was obtained. Moreover, TGA methods allow distinguishing various stages of the gasification process such as primary pyrolysis, secondary pyrolysis and gasification, and determining kinetic parameters for each stage. The presented methods differs from each other as they are based either on the analysis of changes in the resulting product or on the analysis of changes in the supplied feedstock, but both can be successfully used to the effective examination of kinetics of the gasification process. In addition, an important advantage of both methods is the possibility to carry out the gasification process for different solid fuels as coal, biomass, or solid waste in the atmosphere of a variety of gasification agents.

scholarly journals Examination of steam gasification of coal with physically mixed catalysts

2019 ◽  
Vol 21 (4) ◽  
pp. 51-57 ◽  
Author(s):  
Katarzyna Śpiewak ◽  
Grzegorz Czerski ◽  
Agnieszka Sopata
Keyword(s):  
Coal Gasification ◽  
Steam Gasification ◽  
Conversion Degree ◽  
Process Time ◽  
Gasification Process ◽  
Kinetics Of Formation ◽  
Short Time ◽  
Kinetics Of ◽  
Positive Effect

Abstract The aim of this study was to analyse the steam gasification process of ‘Janina’ coal with and without Na-, K- and Ca-catalysts. The catalysts were physically mixed with the coal due to the simplicity of this method, short time of execution and certainty that the amount of catalyst is exactly as the adopted one. The isothermal measurements were performed at 800, 900 and 950°C and a pressure of 1 MPa using thermovolumetric method. The obtained results enabled assessment of the effect of analysed catalysts on the process at various temperatures by determination of: i) carbon conversion degree; ii) yield and composition of the resulting gas; and iii) kinetics of formation reactions of main gas components – CO and H2. The addition of catalysts, as well as an increase in operating temperature, had a positive effect on the coal gasification process – reactions rates increased, and the process time was reduced.

scholarly journals Determination of the kinetic constants of the process of plasma gasification of coal-water fuel

2019 ◽  
Vol 109 ◽  
pp. 00034
Author(s):  
Leonid Kholiavchenko ◽  
Yevhen Pihida ◽  
Serhii Demchenko ◽  
Serhii Davydov
Keyword(s):  
Kinetic Constants ◽  
Carbon Conversion ◽  
Thermal Transformations ◽  
Plasma Gasification ◽  
Gaseous Environment ◽  
Gasification Process ◽  
High Temperature Processing ◽  
Fuel Particles ◽  
Kinetics Of

The chemical kinetics of processes of thermal transformations of carbon-containing media was studied at high-temperature processing (2000 K ≤ T ≤ 5000 K) in the chamber of a plasma-jet reactor using water vapor as an oxidizer. The chemical reactions rate was calculated according to the method of determining the kinetic constants of the process of gasification of coal-water fuel. The influence of the temperature of the gaseous environment in the chamber on the time of complete carbon conversion of the fuel particles is established. An example of calculating the parameters of the gasification process of coke residue particles with a size of (5 - 20)·10-5 m with an oxidizer excess coefficient α = 0.45 and fuel consumption mf = 100 kg/hr is given. The expediency of the process of vapor-plasma gasification at the temperature of gases in the reactor chamber up to 3000 K is shown.

scholarly journals Gasification Kinetics of Bituminous Coal Char in the Mixture of CO2, H2O, CO, and H2

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 496 ◽  
Author(s):  
Junwei Chen ◽  
Weibin Chen ◽  
Yang Jiao ◽  
Xidong Wang
Keyword(s):  
Bituminous Coal ◽  
Gas Diffusion ◽  
Coal Char ◽  
Conversion Degree ◽  
Diffusion Control ◽  
Diffusion Resistance ◽  
Gasification Process ◽  
Control Step ◽  
Kinetics Of ◽  
Gasification Temperature

The gasification kinetics of bituminous coal char was investigated in a mixture of CO2, H2O, CO, H2, and N2 under isothermal conditions. In addition, the impacts of gasification temperature, gasification time, and gas composition on the gasification process were analyzed. As the experimental results suggest, there is a significant increase of the carbon conversion degree of bituminous coal char not just when gasification temperature and time increase, but also when H2 and CO concentration decreases. The kinetics of bituminous coal char in the gasification process was successfully modeled as a shrinking unreacted core. It is concluded that the gasification of bituminous coal char is controlled by an internal chemical reaction in the early stage and diffusion in the later stage. The activation energies of bituminous coal char gasification for different stages were studied. Moreover, it is proposed for the first time, to our knowledge, that the diffusion-control step is significantly shortened with the decrease of the CO2/H2O ratio. As scanning-electron-microscopy results suggest, bituminous coal char gasified in CO2/H2O = 1/3 atmosphere has numerous inner pores (0–5 m). Therefore, in the process of gasification, the inner pores provide a gas channel that reduces the gas diffusion resistance and thus shortens the diffusion-control step. These results can serve as a reference for industrialized application of the technology of coal gasification direct reduced iron.

scholarly journals Development of method for determination of the kinetics constants of coal char gasification in pore diffusion regimes

2019 ◽  
Vol 114 ◽  
pp. 07007
Author(s):  
Irina Remkunas ◽  
Igor Donskoy ◽  
Aleksandr Kozlov
Keyword(s):  
Heterogeneous Reactions ◽  
Kinetic Constants ◽  
Carbon Conversion ◽  
Porous Sample ◽  
Char Gasification ◽  
Gasification Process ◽  
Diffusion Controlled ◽  
Reliable Assessment ◽  
Coal Char Gasification

In this paper, we developed a method for determining the kinetic constants of partially diffusion-controlled heterogeneous reactions in a porous sample of powder. Studies have been conducted on the experimental data of thermogravimetric analysis of carbon conversion in a stream of CO2, using a new method of processing kinetic curves, to obtain updated values of the kinetic constants under conditions where widely used models are inappropriate. Data obtained can be used for a reliable assessment of the characteristics of the gasification process.

scholarly journals Studies of catalytic coal gasification with steam

2016 ◽  
Vol 18 (3) ◽  
pp. 97-102 ◽  
Author(s):  
Stanisław Porada ◽  
Andrzej Rozwadowski ◽  
Katarzyna Zubek
Keyword(s):  
Coal Gasification ◽  
High Reactivity ◽  
Conversion Degree ◽  
Clean Coal ◽  
Catalytic Gasification ◽  
Gasification Process ◽  
Catalytically Active ◽  
Gasification Products ◽  
Isothermal Measurements

Abstract One of the promising processes, belonging to the so-called clean coal technologies, is catalytic coal gasification. The addition of a catalyst results in an increased process rate, in which synthesis gas is obtained. Therefore, the subject of this research was catalytic gasification of low-ranking coal which, due to a high reactivity, meets the requirements for fuels used in the gasification process. Potassium and calcium cations in an amount of 0.85, 1.7 and 3.4% by weight were used as catalytically active substances. Isothermal measurements were performed at 900°C under a pressure of 2 MPa using steam as a gasifying agent. On the basis of kinetic curves, the performance of main gasification products as well as carbon conversion degree were determined. The performed measurements allowed the determination of the type and amount of catalyst that ensure the most efficient gasification process of the coal ‘Piast’ in an atmosphere of steam.

Determination of microbiological activity during the processing of frost damaged sugar beets

2014 ◽  
pp. 228-231 ◽  
Author(s):  
Maciej Wojtczak ◽  
Aneta Antczak-Chrobot ◽  
Edyta Chmal-Fudali ◽  
Agnieszka Papiewska
Keyword(s):  
Sugar Beet ◽  
Microbiological Activity ◽  
Microbiological Contamination ◽  
Sugar Beets ◽  
Bacterial Metabolites ◽  
Kinetics Of

The aim of the study is to evaluate the kinetics of the synthesis of dextran and other bacterial metabolites as markers of microbiological contamination of sugar beet.

Studies on the Behavior Some Paints in Electro-insulating Fluid Based on Vegetable Esters

2018 ◽  
Vol 69 (5) ◽  
pp. 1139-1144
Author(s):  
Iosif Lingvay ◽  
Adriana Mariana Bors ◽  
Livia Carmen Ungureanu ◽  
Valerica Stanoi ◽  
Traian Rus
Keyword(s):  
Structural Changes ◽  
Oxidation Processes ◽  
High Oleic ◽  
Painting Materials ◽  
Insulating Paper ◽  
Different Types ◽  
Mechanism And Kinetics ◽  
Kinetics Of ◽  
Natural Ester

For the purpose of using three different types of painting materials for the inner protection of the transformer vats, their behavior was studied under actual conditions of operation in the transformer (thermal stress in electro-insulating fluid based on the natural ester in contact with copper for electro-technical use and electro-insulating paper). By comparing determination of the content in furans products (HPLC technique) and gases formed (by gas-chromatography) in the electro-insulating fluid (natural ester with high oleic content) thermally aged at 130 �C to 1000 hours in closed glass vessels, it have been found that the presence the investigated painting materials lead to a change in the mechanism and kinetics of the thermo-oxidation processes. These changes are supported by oxygen dissolved in oil, what leads to decrease both to gases formation CO2, CO, H2, CH4, C2H4 and C2H6) and furans products (5-HMF, 2-FOL, 2 -FAL and 2-ACF). The painting materials investigated during the heat treatment applied did not suffer any remarkable structural changes affecting their functionality in the electro-insulating fluid based on vegetable esters.

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