Results of Bituminous Coal Gasification upon Exposure to a Pressurized Pilot-Plant Circulating Fluidized-Bed (CFB) Reactor

Duan, Feng; Jin, Baosheng; Huang, Yaji; Li, Bin; Wu, Yiming; Zhang, Mingyao

doi:10.1021/ef901596n

Cited by 33 publications

(17 citation statements)

References 22 publications

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“…[40,51].T he TGA experiments were isothermal, and the gasification temperature was 900 8C, which is at ypical temperature for ac irculating fluidized-bed (CFB) gasifier. [52] ForH 2 O gasification, the gasification agent was 50 %H 2 O + 50 %N 2 .F or CO 2 gasification, the gasification agent was 100 %C O 2 .S ome pre-tests were conducted at first to choose the proper sample weight and gas flow rate for the suppression of diffusion effects. Thes ample mass is 10 AE 0.3 mg, and the flow rates for CO 2 and H 2 Og asification are 600 and 643 mL min À1 (standard temperature and pressure), respectively.…”

Section: Char Gasificationmentioning

confidence: 99%

Effects of Pyrolysis Atmosphere and Temperature on Coal Char Characteristics and Gasification Reactivity

et al. 2016

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Coal chars are usually produced under complex atmospheres in industrial production. However, most of the research about char characteristics and gasification reactivity uses the coal char samples prepared under an inert atmosphere. In this study, the influences of the pyrolysis atmosphere and temperature on coal char characteristics and gasification reactivity were investigated. A Shanxi bituminous coal was pyrolyzed in a bubbling fluidized bed to produce char samples. A mixture of hydrogen (H2), carbon dioxide (CO2), carbon monoxide (CO), and methane (CH4) was used as simulated pyrolysis gas (SPG). The coal was pyrolyzed in the SPG and N2 atmospheres, respectively. SEM, Raman spectroscopy, and FTIR spectroscopy were used to study the influences of the pyrolysis atmosphere and temperature on the coal char characteristics. The char–H2O and char–CO2 gasification reactivities were measured by using a modified thermogravimetric analysis (TGA) system. The experimental results indicate that the SPG atmosphere has no obvious influence on the coal char morphology, but it has significant influences on the carbon structures and surface chemical groups. The SPG char samples have lower gasification reactivity. The disproportionation reaction of CO, the decomposition reaction of CH4, and the loss of oxygen‐containing structures induced by H2 lead to a higher‐ordered degree of char, and the graphite generated from the disproportionation reaction and the decomposition reaction can decrease the specific surface area of the coal char. These two reasons result in the lower gasification reactivity of SPG char.

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Section: Char Gasificationmentioning

confidence: 99%

Effects of Pyrolysis Atmosphere and Temperature on Coal Char Characteristics and Gasification Reactivity

et al. 2016

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“…The main reactions involved in char gasification can be divided into two types: gas–solid reactions and gas–gas reactions . These reactions are listed below:…”

Section: Resultsmentioning

confidence: 99%

Coal Char Gasification on a Circulating Fluidized Bed for Hydrogen Generation: Experiments and Simulation

et al. 2015

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Char is the solid product of coal pyrolysis and its utilization is closely related to the scale of coal pyrolysis and tar processing. Char gasification is a promising choice for char utilization as it can provide hydrogen, which is needed for tar hydrogenation and chemical synthesis. However, reliable and mature coal char gasification technology has not yet been developed. The fluidized bed has been adopted as a gasifier in many studies, and its gasification temperature is relatively low. In this work, the feasibility of char gasification using a fluidized bed has been studied. A pyrolyzed bituminous coal char was gasified in a mixture of O2 and steam using a circulating fluidized bed. The height of the fluidized bed is 2360 mm and the inner diameter is 66 mm. The reactor is made of Ni‐Cd alloy steel, and a loopseal was used for solid circulation. In the experiments, the gasification temperature was varied between 870 and 900 °C, and the effects of O2/char and steam/char mass ratios on the gasification results were analyzed. The volume fraction of combustible gas, dry gas yield, carbon conversion, and lower heating value of the best case were 43.92 %, 1.64 Nm3 kg−1, 0.85, and 5.17 MJ N m−3, respectively. In addition, a simple model and a complex model were established by using Aspen Plus software. The two models were used to simulate char gasification, and the simulation results were validated with the experimental results. The results indicated that the complex model is more accurate than the simple model and is more suitable to simulate char gasification in a circulating fluidized bed.

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“…Another study was carried out in this pressurized CFB bed to find the optimum operating range for gasification using bituminous coal in this pilot plant test. [10] These gasification parameters provided optimum operating condition when the ER is about 0.33, and steam/coal ratio is 0.38 kg/kg. The fly ash discharged from the secondary cyclone was analyzed to determine its carbon content.…”

Section: Methodsmentioning

confidence: 95%

“…The equivalence ratio and steam/coal ratio are the most important operating parameters in the gasification process. Another study was carried out in this pressurized CFB bed to find the optimum operating range for gasification using bituminous coal in this pilot plant test . These gasification parameters provided optimum operating condition when the ER is about 0.33, and steam/coal ratio is 0.38 kg/kg.…”

Section: Methodsmentioning

confidence: 99%

Dependence of bituminous coal gasification on pressure in a turbulent circulating fluidized bed

Duan

Zhang

Huang

2011

Asia-Pacific J Chem Eng

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The concept of high‐temperature air/steam‐blown gasification technology to convert coal into fuel gas for power generation is proposed and evaluated. The effect of the pressure on coal gasification characteristics is studied experimentally by using a pressurized turbulent circulating fluidized bed (CFB). The results show that the product quality is improved at higher pressure because of the better fluidization in the reactor. Coal gasification at a higher pressure shows advantages in higher heating value (HHV) and carbon conversion. The HHV is increased by 16.6% when the pressure is increased from 0.1 to 0.3 MPa. The increase of the pressure increases the carbon conversion from 57.52% to 76.76%. In addition, dry gas yield and cold gas efficiency increase while the carbon content of fly ash decreases with the increase of pressure. Optimum operating pressure range exists for this specific CFB coal gasification process. © 2011 Curtin University of Technology and John Wiley & Sons, Ltd.

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Results of Bituminous Coal Gasification upon Exposure to a Pressurized Pilot-Plant Circulating Fluidized-Bed (CFB) Reactor

Cited by 33 publications

References 22 publications

Effects of Pyrolysis Atmosphere and Temperature on Coal Char Characteristics and Gasification Reactivity

Effects of Pyrolysis Atmosphere and Temperature on Coal Char Characteristics and Gasification Reactivity

Coal Char Gasification on a Circulating Fluidized Bed for Hydrogen Generation: Experiments and Simulation

Dependence of bituminous coal gasification on pressure in a turbulent circulating fluidized bed

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