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Title: One-Dimensional Dynamic Modeling of a Single-Stage Downward-Firing Entrained-Flow Coal Gasifier

Authors:
; ; ;
Publication Date:
Research Org.:
National Energy Technology Lab. (NETL), Pittsburgh, PA, and Morgantown, WV (United States). In-house Research
Sponsoring Org.:
USDOE Office of Fossil Energy (FE)
OSTI Identifier:
1165548
Report Number(s):
A-UNIV-PUB-099
Journal ID: ISSN 0887-0624
DOE Contract Number:
DE-FE0004000
Resource Type:
Journal Article
Resource Relation:
Journal Name: Energy and Fuels; Journal Volume: 28; Journal Issue: 8
Country of Publication:
United States
Language:
English

Citation Formats

Kasule, Job S, Turton, Richard, Bhattacharyya, Debangsu, and Zitney, Stephen E. One-Dimensional Dynamic Modeling of a Single-Stage Downward-Firing Entrained-Flow Coal Gasifier. United States: N. p., 2014. Web. doi:10.1021/ef5010122.
Kasule, Job S, Turton, Richard, Bhattacharyya, Debangsu, & Zitney, Stephen E. One-Dimensional Dynamic Modeling of a Single-Stage Downward-Firing Entrained-Flow Coal Gasifier. United States. doi:10.1021/ef5010122.
Kasule, Job S, Turton, Richard, Bhattacharyya, Debangsu, and Zitney, Stephen E. Thu . "One-Dimensional Dynamic Modeling of a Single-Stage Downward-Firing Entrained-Flow Coal Gasifier". United States. doi:10.1021/ef5010122.
@article{osti_1165548,
title = {One-Dimensional Dynamic Modeling of a Single-Stage Downward-Firing Entrained-Flow Coal Gasifier},
author = {Kasule, Job S and Turton, Richard and Bhattacharyya, Debangsu and Zitney, Stephen E},
abstractNote = {},
doi = {10.1021/ef5010122},
journal = {Energy and Fuels},
number = 8,
volume = 28,
place = {United States},
year = {Thu Aug 21 00:00:00 EDT 2014},
month = {Thu Aug 21 00:00:00 EDT 2014}
}
  • The integrated gasification combined cycle (IGCC) technology has emerged as an attractive alternative to conventional coal-fired power plant technology due to its higher efficiency and cleaner environmental performance especially with the option of CO{sub 2} capture and sequestration. The core unit of this technology is the gasifier whose optimal performance must be understood for efficient operation of IGCC power plants. This need has led a number of researchers to develop gasifier models of varying complexities. Whereas high-fidelity CFD models can accurately predict most key aspects of gasifier performance, they are computationally expensive and typically take hours to days to executemore » on high-performance computers. Therefore, faster one-dimensional (1D) partial differential equation (PDE)-based models are required for use in dynamic simulation studies, control system analysis, and training applications. A number of 1D gasifier models can be found in the literature, but most are steady-state and have limited application in the practical operation of the gasifier. As a result, 1D PDE-based dynamic models are needed to further study and predict gasifier performance under a wide variety of process conditions and disturbances. In the present study, a 1D transient model of a single-stage downward flow GE/Texaco-type gasifier has been developed. The model comprises mass, momentum and energy balances for the gas and solid phases. The model considers the initial gasification processes of water evaporation and coal devolatilization. In addition, the key heterogeneous and homogeneous chemical reactions have been modeled. The resulting time-dependent PDE model is solved using the well-known method of lines approach in Aspen Custom Modeler®, whereby the PDEs are discretized in the spatial domain and the resulting differential algebraic equations (DAEs) are then solved to obtain the transient response. The transient response of various gasifier performance parameters to certain disturbances commonly encountered in the real world operation of commercial IGCC plants will be presented. These disturbances include ramp and step changes in input variables such as coal flow rate, oxygen-to-coal ratio and water-to-coal ratio, among others. Comparison of gasifier model predictions to available dynamic data will also be discussed.« less
  • The gasifier is the heart of the integrated gasification combined cycle (IGCC), a technology that has emerged as an attractive alternative to conventional coal-fired power plant technology due to its higher efficiency and cleaner environmental performance especially with the option of CO{sub 2} capture and sequestration. Understanding the optimal performance of the gasifier is therefore paramount for the efficient operation of IGCC power plants. Numerous gasifier models of varying complexity have been developed to study the various aspects of gasifier performance. These range from simple one-dimensional (1D) process-type models to rigorous higher order 2-3D models based on computational fluid dynamicsmore » (CFD). Whereas high-fidelity CFD models can accurately predict most key aspects of gasifier performance, they are computationally expensive and typically take hours to days to execute on high-performance computers. Therefore, faster 1D partial differential equation (PDE)-based models are required for use in dynamic simulation studies, control system analysis, and training applications. A number of 1D gasifier models can be found in the literature, but most are steady-state models that have limited application in the practical operation of the gasifier. As a result, 1D PDE-based dynamic models are needed to further study and predict gasifier performance under a wide variety of process conditions and disturbances. In the current study, a 1D transient model of a single-stage downward-fired GE/Texaco-type entrained-flow gasifier has been developed. The model comprises mass, momentum and energy balances for the gas and solid phases. The model considers the initial gasification processes of water evaporation and coal devolatilization. In addition, the key heterogeneous and homogeneous chemical reactions have been modeled. The resulting time-dependent PDE model is solved using the well-known method of lines approach in Aspen Custom Modeler®, whereby the PDEs in the spatial domain are discretized and the resulting differential algebraic equations (DAEs) are then integrated over time using a dynamic integrator. The dynamic response results of the gasifier performance parameters to certain disturbances commonly encountered during practical operation are presented. These disturbances include ramp and step changes to input variables such as coal flow rate, oxygen-to-coal ratio and water-to-coal ratio among others. Comparison of model predictions to available dynamic data will also be discussed.« less
  • No abstract prepared.
  • A transient, multidimensional computer model has been developed to simulate the detailed phenomena occurring in the general class of single-stage entrained flow gasification reactors. Application of the computer simulation code has been specifically demonstrated for the Texaco class of gasifiers. The EEF (EPRI Entrained Flow) computer simulation model accounts for the coupled chemistry and turbulent hydrodynamics associated with coal-water slurry and oxygen injection including droplet and coal moisture vaporization, coal pyrolysis, char combustion and gasification, gas phase combustion as well as intraphase and interphase (turbulent) transport of mass, momentum, and energy. A generalized finite element geometry is used in one-dimensional,more » two-dimensional (Cartesian or axisymmetric), and three-dimensional modes. The theoretical formulation of the model is presented and several calculations of different types described. Three different approximations to the Texaco reactor design have been examined and the resulting similarities/differences discussed. Possible implications for scaleup and gasification-combined cycle operation have been noted.« less