Numerical Simulation of Ash Deposition in Entrained-Flow Gasifier

Author(s):  
Min Du ◽  
Yingli Hao
Author(s):  
Lei Wang ◽  
Jianliang Xu ◽  
Juntao Wei ◽  
Qinghua Guo ◽  
Yan Gong ◽  
...  

2012 ◽  
Vol 51 (6) ◽  
pp. 2560-2569 ◽  
Author(s):  
Zhonghua Sun ◽  
Zhenghua Dai ◽  
Zhijie Zhou ◽  
Qinghua Guo ◽  
Guangsuo Yu

Author(s):  
Hiroaki Watanabe ◽  
Kazuyoshi Ichikawa ◽  
Maromu Otaka ◽  
Jun Inumaru

The objective of this study is to develop an evaluation tool for a design and performance of a coal gasifier by a numerical simulation technique. In the present paper, a gas-particle two phase reacting flow calculation is carried out for a prediction of phenomena in an entrained flow coal gasifier due to coal and ash particles behavior, such as ash deposition on the wall. A transportation of the coal particles is modeled via a Lagrangian manner. The ash particle adhesion on the wall of the gasifier is discriminated by an empirical ash adhesion model based on a liquid phase fraction concept in the ash particle. The gas phase properties are calculated by three dimensional time-mean Eulerian conservation equations. The turbulent flow field is determined by the k-ε two equations model. Radiative heat transfer is calculated by the discrete transfer radiation method. Coal gasification reaction model is composed of three chemical processes in the current model: a pyrolysis, a char gasification and gas phase reactions. 2 tons/day (t/d) air-blown pressurized entrained flow coal gasifier, which has been constructed and operated by Central Research Institute of Electric Power Industry (CRIEPI) was targetted. As a result, a relationship between an operating condition (air ratio) of the gasifier and the gasifier performance is presented. The trend of the ash deposition on the gasifier inner wall is also presented. Comparison between the computational and the experimental results shows that the most feature of the gasifier performance and the profile of the ash deposition have been captured by the present model. It was confirmed that the numerical simulation approach is very useful for the assessment of gasifier performance and operation support.


2012 ◽  
Vol 524-527 ◽  
pp. 1943-1946
Author(s):  
Zhi Qiang Wu ◽  
Shu Zhong Wang ◽  
Lin Chen ◽  
Jun Zhao ◽  
Hai Yu Meng

The swirl flow could enhance the turbulent mixing and promote the slagging in the entrained flow gasifier. In recent research, the effect of swirl flow on cold flow characteristic of entrained flow gasifier was neglected or simplified. To address this, a three-dimensional computational fluid dynamic (CFD) simulation was presented to investigate the effect of swirl flow on the cold flow characteristic of entrained flow gasifier. Several control parameters, i.e., the diameter and injection velocity of nozzles, were found to significantly affect swirl intensity and velocity distribution in the entrained flow gasifier. Our numerical simulation provides an effective way for researchers or engineers to optimize and scale up the gasifier and nozzle.


Author(s):  
Hiroaki Watanabe ◽  
Maromu Otaka ◽  
Saburo Hara ◽  
Masami Ashizawa ◽  
Kazuhiro Kidoguchi ◽  
...  

The objective of this study is to develop an evaluation tool for a design and performance of an extra heavy oil gasifier by a numerical simulation technique. The modelling and the numerical simulation for the extra heavy oil gasification on the 2.4 tons/day entrained flow gasifier of CRIEPI are described in this paper. The gas phase properties are calculated by three dimensional time-mean Eulerian conservation equations, in addition to the k-ε turbulence model. The fuel droplet behavior is modelled via a Lagrangian particle tracking approach. Four reaction processes are modelled in the present paper: atomization (micro-explosion), pyrolysis, coke gasification reaction, and gaseous phase reaction. As a result of the simulation, in a relationship between an oxygen ratio of the gasifier and the gasifier performance, such as heating value of the product gas, carbon conversion efficiency are presented. Distribution of gas temperature and gas composition in the gasifier, and the product gas composition are also presented. Comparison between the computational and the experimental results shows that the most features of the gasifier performance have been captured accurately by the computational procedure. The numerical simulation approach is very useful for the assessment of gasification performance, operation support and optimization of the gasifier design.


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