Performance Evaluation of Syngas Production in the Low-Rank Coal/Biomass Co-gasification Process using Aspen Plus Simulation
- 주제(키워드) Gasification , Syngas , Co-gasification , Low-rank coal , Biomass , Carbon conversion , Cold gas efficiency , Aspen Plus.
- 발행기관 아주대학교
- 지도교수 Hyung-Taek Kim
- 발행년도 2015
- 학위수여년월 2015. 8
- 학위명 석사
- 학과 및 전공 일반대학원 에너지시스템학과
- 실제URI http://www.dcollection.net/handler/ajou/000000020203
- 본문언어 영어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
Co-gasification of coal and biomass is the new sensation in energy production as it provides two benefits: coal for high density of energy and biomass for a clean and renewable energy source. The advantages of the gasification process are many. The producer gas from gasification is multipurpose and can be used for producing electricity in gas engines and turbines, for Fischer-Tropsch synthesis of liquid fuel and even for producing gaseous products such as synthetic natural gas like the SNG. A variety of mixtures and compositions of coal and wood provides great flexibility that best fits the desired product. In this study a basic gasification model is developed by Aspen plus Simulation Software based on the report of low rank coal to electricity IGCC cases. Simulation of different coal and wood (Radiata pine) co-gasification process was performed by applying the basic model. Entrained flow Siemens water quenched gasifier is proposed for the basic model for simulating gasification of different ratio of fuel blend. 40% lignite and 60% radiata pine, 70% lignite and 30% radiata pine, 80% lignite and 20% radiate pine, and finally 100 % lignite used for the co- gasification model. Carbon conversion and cold gas efficiency are also calculated to determine energy efficiency. Sensitivity analysis was also performed according to pressures and oxygen/ fuel blend ratios. A Low oxygen amount is required for co-gasification compared to 100% lignite coal. And there is no big pressure effect on the gas compositions production. From the result it clearly show that the 80% lignite coal and 20% radiata pine produces the highest amount of syngas compared to other fuel blend ratios. Biomass is carbon neutral and it is proved as it shows that the effective amount of CO2 is very low. On the other side H2S and NH3 mole flow increased after increasing the coal amount in the blend ratio. The final output of the syngas H2/ CO also indicated a good ratio for 80% lignite and 20% radiate pine.
more목차
Chapter 1. Introduction
1.1 Introduction 1
1.2 Objectives 2
Chapter 2. Literature Review
2.1 Coal and Biomass as an Alternative Energy Resource 4
2.2 Potential of Combined Usage of Coal and Biomass 4
2.3 Thermochemical Conversion of Solid Fuel 7
2.4 Gasification Process 9
2.5 Classification of Gasifier 10
2.5.1 Fixed Bed Gasifiers 11
2.5.2 Fluidized Bed Gasifiers 12
2.5.3 Entrained Bed Gasifiers 13
2.6 Co-Gasification of Coal / Biomass 14
2.7 Previous Study of Co-Gasification 16
2.8 Fuel Characteristics 17
2.8.1 Coal 17
2.8.1(a) Types of Coal 18
2.8.1(b) Low Rank Coal Structure Characteristics 18
2.8.1 (c) Availability of Low Rank Coal in the World 19
2.8.2 Biomass 21
Chapter 3. Simulation Model Description
3.1 The Fundamental of Coal/Biomass Co-Gasification Plant 22
3.1.1 The Basic Analysis of North Dakota Beulah-Zap Lignite Coal
22
3.1.2 Coal/ Biomass Co-Gasification Process 23
3.2 Aspen Plus 24
3.3 Description of Basic Simulation Model 25
3.3.1 Fuel Preparation Process 25
3.3.1. (a) Theoretical Explanation of Fuel Process 25
3.3.1. (b) Simulation Model of Size Reduction Process 26
3.3.1. (c) Simulation Model of drying Process 27
3.3.2 Gasification Process 28
3.3.2. (a) Theoretical Explanation of Siemens Gasifier 28
3.3.2. (b) Simulation Process of Gasification Model 30
3.3.3 Quenching Process 34
3.3.3 (a) Theoretical Explanation of Water Quenching Process 34
3.3.3 (b) Simulation Model of Quenching Process 34
3.3.4 Cos Hydrolysis and AGR Process 36
3.3.4 (a) Theoretical Explanation of Cos Hydrolysis and AGR Process 36
3.3.4 (b) Simulation Model of Cos Hydrolysis and AGR Process 36
3.3.5 Full Gasification Model in Aspen Plus: 39
3.4 Co-Gasification 40
3.4.1 The Basic Analysis of Coal / Biomass Mixture for Co- Gasification Plant 40
3.4.2 Simulation Model of Coal and Biomass Blend 41
3.4.3 Full Co-Gasification Model in Aspen Plus 42
Chapter 4. Results and Discussions
4.1 Input Data 43
4.2 Model Validation 44
4.2.1 Simulation Results 44
4.2.2 Different Stage Simulation Results and Report Data 46
4.3 Co-Gasification 49
4.3.1 Input Data 49
4.3.2 Sensitivity Analysis 50
4.3.2(a) Sensitivity Analysis of Oxidant for Gas Composition 50
4.3.2 (b) Sensitivity Analysis of Oxidant for Carbon Conversion and Cold Gas Efficiency 52
4.3.2 (c) Sensitivity Analysis of the Pressure effect for Syngas Composition 54
4.3.3 Raw Syngas Compositions of Various Fuel Blend Ratios 55
4.3.4 Amount of CO2 on Syngas Composition 56
4.3.5 Amount of H2S on Syngas Composition 57
4.3.6 Amount of NH3 on Syngas Composition 58
4.3.7 H2 /CO Ratio Comparison with respect to Lignite Ratio 59
4.3.8 Mass Flow Rate of Syngas on Different Blend Ratio 60
Chapter 5. Conclusion
5.1 Conclusion 61
5.2 Further Study 63
References 64
Recent Publications 69
Biography 70
