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Evaluation of ash deposition behavior and fine particle formation from combustion of low-rank coal impregnated with molasses in DTF
| DC Field | Value | Language |
|---|---|---|
| dc.contributor.advisor | Hyung-taek Kim | - |
| dc.contributor.author | XU ZIXIANG | - |
| dc.date.accessioned | 2019-08-13T16:41:06Z | - |
| dc.date.available | 2019-08-13T16:41:06Z | - |
| dc.date.issued | 2019-08 | - |
| dc.identifier.other | 29042 | - |
| dc.identifier.uri | https://dspace.ajou.ac.kr/handle/2018.oak/15534 | - |
| dc.description | 학위논문(석사)--아주대학교 일반대학원 :에너지시스템학과,2019. 8 | - |
| dc.description.tableofcontents | Contents Chapter 1 Introduction 1 1.1 Background 1 1.2 Motivation and Objective 4 1.3 Thesis Outline 5 Chapter 2 Literature Review 7 2.1 An Overview of Low-Rank Coal Impregnated with Molasses (HCK) 7 2.2 An Overview to Ash Deposition 8 2.2.1 Introduction to Ash Deposition 8 2.2.2 Transformation of Mineral Matter in Ash 9 2.2.3 Ash Deposition Mechanism 15 2.2.4 Factors Affecting the Ash Deposition 18 2.3 An Overview of Fine Particle Formation 19 2.3.1 An Introduction of Fine Particles 19 2.3 2 The Formation Mechanism of Fine Particles 21 2.3.3 Elemental Evolution process of Fine Particles 23 2.3 4 Factors Affecting the Formation of Fine Particles 24 Chapter 3 Experimental Sections 25 3.1 Sample Preparation 25 3.2 Samples Properties 26 3.3 Experimental Facility and Method 28 3.3.1 Experimental Facility 28 3.3.2 Experimental Method 28 3.4 Analytical Methods 30 3.4.1 SEM-EDX 30 3.4.2 XRD 31 Chapter 4 Results and Discussion 32 4.1 The Evaluation of Ash Deposition Behavior 32 4.1.1 The Characteristics of Deposits Through DTF Experiment 32 4.1.2 Prediction of Deposits Components by Theoretical Model 41 4.1.3 Comparison of Ash Deposition Behavior of These Five Fuels 46 4.2 The Characteristics of Fine Particle formation from Different Fuels. 47 4.2.1 The Morphology and Elemental Distribution of Fine Particles 47 4.2.2 Comparison of Fine Particles of These Five Fuels 51 Chapter 5 Conclusions 53 References 55 Abbreviations 61 | - |
| dc.language.iso | eng | - |
| dc.publisher | The Graduate School, Ajou University | - |
| dc.rights | 아주대학교 논문은 저작권에 의해 보호받습니다. | - |
| dc.title | Evaluation of ash deposition behavior and fine particle formation from combustion of low-rank coal impregnated with molasses in DTF | - |
| dc.type | Thesis | - |
| dc.contributor.affiliation | 아주대학교 일반대학원 | - |
| dc.contributor.department | 일반대학원 에너지시스템학과 | - |
| dc.date.awarded | 2019. 8 | - |
| dc.description.degree | Master | - |
| dc.identifier.localId | 952029 | - |
| dc.identifier.uci | I804:41038-000000029042 | - |
| dc.identifier.url | http://dcoll.ajou.ac.kr:9080/dcollection/common/orgView/000000029042 | - |
| dc.description.alternativeAbstract | In recent years, many countries have invested enormous efforts to tackle increasingly harsh environmental problems, especially the greenhouse effect. The addition of biomass into coal is regarded as a promising technology to mitigate CO2 emissions. However, the costs related to retrofitting injection systems and unstable combustion inhibit this option. Therefore, this thesis developed a two-in-one fuel that impregnates molasses into the holes of low-rank coal (LRC), which can be directly applied to existing boilers. However, due to the existence of alkali and alkaline earth metals (AAEMs) in molasses, the impregnation of molasses into the coal pores possibly lead to the ash deposited on the surface of the heat exchanger, reducing the heat exchange efficiency. Besides, a part of fine particles will emit into the atmosphere, resulting in a series of air pollutions. Thus, the investigation of ash deposition and fine particle formation is a significant topic to promote heat exchanger efficiency and protect the environment. In this study, five fuels, Berau coal, Berau coal impregnate with 10wt% and 20wt% molasses, Bayan coal and Bayan coal impregnate with 3wt% molasses are selected. In the following sections, these fuels will be denoted as Berau coal, 10% HCK, 20% HCK, Bayan coal and 3% HCK respectively. Experiments are carried out in drop tube furnace (DTF) under the combustion temperature of 1300°C and the ash probe temperature of 800°C with access air. The fuel is fed at a rate of 0.45g/min for 10min. The properties of the ash deposition and fine particles are characterized. It is concluded that 20% HCK showed the most serious deposition tendency, followed by 10% HCK, Berau coal, Bayan coal and 3% HCK. SEM-EDX, XRD and theoretical model analysis indicate that CaO and Fe2O3 are the main factors affecting the deposition propensity. Meanwhile, the difference between the top and bottom layers are also due to CaO and Fe2O3. As far as the fine particle formation is concerned, it was obvious that volatile elements, K, S and Mg, are rich in fine particles (＜1μm). Si, Al, Ca and Fe are rich in coarse particles (＞1μm), this phenomenon is due to the different formation mechanisms. The boiling point of K, S and Mg is 774°C, 445°C and 1090°C respectively. So, these elements are easy to vaporize and condense to form fine particles (＜1μm). The boiling point of Si, Al, Ca and Fe is 2355°C, 2327°C, 1484°C and 2750°C respectively, it is difficult to vaporize under testing temperature, thus, these elements are rich in coarse particles (＞1μm). | - |
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- Graduate School of Ajou University > Department of Energy Systems > 3. Theses(Master)
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