scholarly journals Investigation of non-isothermal and isothermal gasification process of coal char using different kinetic model

2015 ◽  
Vol 25 (1) ◽  
pp. 15-21 ◽  
Author(s):  
Guangwei Wang ◽  
Jianliang Zhang ◽  
Jiugang Shao ◽  
Kejiang Li ◽  
Haibin Zuo
Keyword(s):  
Kinetic Model ◽  
Coal Char ◽  
Gasification Process

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.

A comprehensive kinetic model for the formation of char-no during the combustion of a single particle of coal char

1988 ◽  
Vol 21 (1) ◽  
pp. 1207-1216 ◽  
Author(s):  
Norio Arai ◽  
Masanobu Hasatani ◽  
Yoshihiko Ninomiya ◽  
Stuart W. Churchill ◽  
Noam Lior
Keyword(s):  
Kinetic Model ◽  
Single Particle ◽  
Coal Char

Pore Structure of Coal-Chars Derived From Atmospheric and Pressurized Spouted Fluidized Bed Gasifiers

2005 ◽  
Author(s):  
Yufeng Duan ◽  
Yi Zhou ◽  
Xiaoping Chen ◽  
Changsui Zhao ◽  
Xin Wu
Keyword(s):  
Pore Structure ◽  
Fluidized Bed ◽  
Positive Impact ◽  
Elevated Pressure ◽  
Influential Factors ◽  
Coal Char ◽  
Operational Conditions ◽  
Gasification Process ◽  
Leading Role ◽  
Partial Gasification

Pore structure is one of the most important factors that dominate the reactivity of post-combustion of coal-chars derived from partial gasification process of atmospheric and pressurized spouted fluidized bed gasifiers. The influential factors on pore structure of coal-chars were analyzed in terms of the coal size feed, operational conditions, coal-char size and its components. It concluded that pyrolysis and devolatilization play a leading role in forming the pore structure of coal-chars in the partial gasification process. It is the reaction of coal-char with CO2 and H2O (steam) that plays a dominant positive impact on promoting enlargement and development of the coal-char pores at the elevated pressure gasification. There may exist an optimal coal-char size range that possesses abundant porosity and bigger pore specific surface area, which contributes to enhancing the gasification reactions in the atmospheric gasifier.

PERFORMANCE OF A PRESSURIZED TWO-STAGE FLUIDIZED GASIFICATION PROCESS FOR PRODUCTION OF LOW-BTU GAS FROM COAL CHAR

1981 ◽  
Vol 11 (6) ◽  
pp. 335-345 ◽  
Author(s):  
JUN-ICHI KAWABATA ◽  
MIDORI YUMIYAMA ◽  
YONESHIRO TAZAKI ◽  
SENJI HONMA ◽  
SHOHEI TAKEDA ◽  
...  
Keyword(s):  
Coal Char ◽  
Two Stage ◽  
Gasification Process

Determination of Char-CO2 Gasification Rate through Reaction Product

2014 ◽  
Vol 953-954 ◽  
pp. 1026-1030
Author(s):  
Yong Zhao ◽  
Jian Sheng Zhang
Keyword(s):  
Kinetic Parameters ◽  
Coal Char ◽  
Clear Understanding ◽  
Weight Loss Curve ◽  
Weight Changes ◽  
Gasification Process ◽  
Gasification Rate ◽  
Product Gas ◽  
Gas Products

This paper presents gasification kinetic parameters generated for Japanese lignite coal char reacting with carbon dioxide and the method for obtaining them. The experiments were conducted in a PTGA at atmospheric pressure within a temperature range of 1148K-1223K, and a mass spectrometer (MS) is coupled with PTGA to obtain the concentrations of product gas. The experiments were carried out with isothermal method, and kinetic parameters were determined through the analysis of the weight changes of coal char and the concentrations of products respectively. The effect of CO2 partial pressure on reaction rate was analyzed by nth order rate equation. It was found that the activation energy of char-CO2 reaction obtained from weight loss curve and product concentrations were 187.9kJ/mol and 187.0kJ/mol respectively, and the reaction order n were 0.24 and 0.222, proving MS a feasible method for kinetics research. Through the comparison, the method to obtain the kinetic data by concentrations of gas products was determined, and a more clear understanding of the gasification process was established.

Non-isothermal study of gasification process of coal char and biomass char in CO2 condition

2017 ◽  
Vol 24 (10) ◽  
pp. 985-990 ◽  
Author(s):  
Tao Xu ◽  
Guang-wei Wang ◽  
Jian-liang Zhang ◽  
Teng-fei Song ◽  
Run-sheng Xu
Keyword(s):  
Coal Char ◽  
Gasification Process ◽  
Biomass Char

scholarly journals Coal char characteristics variation in the gasification process and its influencing factors

2020 ◽  
Vol 38 (5) ◽  
pp. 1559-1573
Author(s):  
Zhenyong Yin ◽  
Hao Xu ◽  
Yanpen Chen ◽  
Tiantian Zhao
Keyword(s):  
Specific Surface ◽  
Pore Structure ◽  
Surface Area ◽  
Inner Mongolia ◽  
Coal Gasification ◽  
Coal Char ◽  
Gasification Process ◽  
Effective Component ◽  
Gasification Temperature ◽  
Better Than

Underground coal gasification is a burgeoning coal exploitation technique that coal is directly converted into gaseous fuel by controlled combustion. In this paper, the gasification experiments of Inner Mongolia lignite, Xinjiang subbituminous coal, and Hancheng medium volatile bitumite were conducted respectively by using the tube furnace coal gasification experiment system. The gasification process was conducted under 3°C/min increment within the range of 600–900°C. The gas composition was analyzed by gas chromatography and the pore structure of the coal char was detected by low-temperature N2 adsorption. The results show that the gasification temperature, gasification agent, and coal type have an important influence on the gasification reaction. With the increase of gasification temperature, the effective component, gas calorific value, and gas production rate increase. When CO2 is used as the gasifying agent, the effective components in the gas are mainly CO. When H2O(g) is used as the gasifying agent, the effective component of gas is H2. The coal gasification performance with low thermal maturity is obvious better than the high rank coal with higher coalification. N2 adsorption–desorption experiments show that the pore is mainly composed by transition pore and the micropores, the specific surface area is chiefly controlled by a pore size of 2–3 nm. With the increase of coalification degree, the adsorption amount, specific surface area, and total pore volume show a decreasing trend. The gasifying agent has a great influence on the pore structure of the coal char. The gasification effect of H2O (g) is significantly better than that of CO2. Analyzing the gasification characteristics and pore changes of different coal rank coals under different gasification agents, we found that Inner Mongolia lignite is more conducive to the transport of gasification agents and gaseous products in coal.

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