A performance analysis of integrated solid oxide fuel cell (SOFC) and heat recovery steam generator (HRSG) for IGFC system by Using Aspen plus
- 주제(키워드) Energy Engineering
- 발행기관 아주대학교
- 지도교수 Professor Dr. Hyung Taek Kim
- 발행년도 2010
- 학위수여년월 2010. 2
- 학위명 석사
- 학과 및 전공 일반대학원 에너지시스템학부
- 실제URI http://www.dcollection.net/handler/ajou/000000010369
- 본문언어 영어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
The solid oxide fuel cell (SOFC) is a promising technology for electricity generation. Sulfur free syngas from the gas cleaning unit serves as a fuel for SOFC in IGFC (Integrated gasification Fuel cell) power plant. It converts the chemical energy of the fuel gas directly to electric energy and therefore, very high efficiencies can be achieved. The high operating temperature of the SOFC also provides excellent possibilities for cogeneration application. The outputs from SOFC can be utilized by HRSG which drives steam turbine for electricity production. Recent developments in modeling techniques has resulted in a more accurate fuel cell model giving an advantage over previous system studies based on simplified SOFC models. The objective of this work is to develop a simulation model of a SOFC for IGFC system, flexible enough for use in future development, capable of predicting system performance under various operating conditions and using diverse fuels. The SOFC stack model developed using the chemical process flow sheet simulator Aspen Plus which is of equilibrium type and is based on Gibbs free energy minimization. The SOFC model performs heat and mass balances and considers the ohmic, activation and concentration losses for the voltage calculation and some graphical presentation of those losses by using MATLAB software. A various range of syngas properties has been used for the simulation which is gathered from different literatures. The results indicate there must be tread off efficiency and power with respect to a variety of SOFC inputs. SOFC stack operation on syn-gas is compared to operation on different coal properties and as expected there is a drop in performance, which is attributed to increased input fuel and air flow due to the lower quality of the fuel gas. HRSG which is located after the SOFC will be included in current simulation study with various operating parameters. This paper also describes for the IGFC Power Plants, the optimization of the Heat Recovery Steam Generator (HRSG) is of particular interest in order to improve the efficiency of the heat recovery from SOFC exhaust gas and to maximize the power production in the steam cycle in IGFC system. It also delineates a thermodynamic optimization of the operating parameters for the HRSG. Based on SOFC output, HRSG output from different pressure levels are also varied. Steam turbine efficiency has calculated for measuring the total power plant output. Various HRSG configurations have been analyzed, from their two case has selected, the simpler; the common configuration of three-pressure steam generator with seven different sections is to be considered as case ‘1’ and triple pressure with reheat and other different components is to be consider as case ‘2’. The aim of this paper is to provide a simulation model for the optimal selection of the operative parameters of the HRSG and SOFC by comparing with other model.
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Contents
Abstract……………………….............................................................................ii
Acknowledgement……………………………………………………………..iv
Contents………………………………………………………………………...v
List of Figures……………………………………………….…………………vii
List of Tables.....................................................................................................viii
Chapter 1:
1.1Introduction……………………………………………………..………..…..1
1.2Motivation………………………………………….………………………...3
1.3Objectives……………………………………………………………………5
Chapter 2:
2.1 Model Description………………………………………………………......6
2.2 Basic Principles of Fuel Cells………………………………………….…....8
2.2.1. Introduciton to Solid Oxide Fuel Cells (SOFC)………… …………10
2.2.2. SOFC Fundamentals………………………………………………...10
2.3. Heat Recovery Steam Generator. (HRSG)………………… …………….11
2.3.1. Analysis of HRSG…………………………………………………..11
2.3.2. The gas-side effectiveness of a heat exchanger……………………..13
2.3.3. Heat exchanger with two or more parallel streams of water………..15
2.4. Thermodynamic efficiency………………………………………………. 17
2.4.1 For SOFC…………………………………………………….……….17
2.4.2 Steam turbine efficiency…………………………………………...…19
Chapter 3:
3 Simulation Procedure………………………………………………………..21
3.1. Aspen Plus………………………………………………………………...21
3.2. SOFC simulation model…………………………………………………..21
3.3 Voltage calculation for SOFC……………………………………………..24
3.3.1 Ohmic loss….…………………………………………………….…25
3.3.2 Activation loss………………………………………..……………..26
3.3.3 Concentration loss……………………………………………..…....27
3.4. Simulation model for HRSG in Aspen Plus………………………………29
3.4.1 Case 1…………………………………………………………….….29
3.4.2 Case 2……………………………………………………….…….…31
Chapter 4:
4 Results…………………………………………………………………….….34
4.1 Sensitivity Analysis …………………………………………………….....38
4.2 Results analysis for HRSG………………………………………………...40
4.3 Model Validation….…………………………………………………...…..47
Chapter 5:
Conclusion……………………………………………………………………..51
References……………………………………………………………………..52
Recent Publications……………………………………………………………56
