准东煤燃烧过程中碱金属行为的实验研究

论文总字数：24274字

摘 要

研究发现，准东煤中水分、挥发分含量非常高。煤中的Ca、Mg、Na等碱性金属元素含量非常高。准东煤燃烧生成颗粒物的质量尺寸分布曲线有两个峰值点，分别对应两种不同的细颗粒物形成机理：蒸发、成核、凝结机理以及破碎、熔融机理。热解气氛下的亚微米颗粒物生成量远远大于燃烧以及CO₂气化气氛下的生成量。转化过程中氧浓度越大，颗粒燃烧温度越高，亚微米颗粒物生成量越多且峰值向大颗粒方向偏移，同时，超微米颗粒物的生成量也越多。DLPI各级颗粒物水溶性物质的IC分析显示，亚微米颗粒物中的碱金属硫酸盐和氯化物含量非常高，说明碱性金属元素对亚微米颗粒物生成的贡献很大。在三种气氛（燃烧、热解和CO₂气化）下，添加高岭土都能在一定程度上减少颗粒物（包括亚微米颗粒物和超微米颗粒物）的生成。

关键词：准东煤；碱金属行为；一维沉降炉；细颗粒物

EXPERIMENTAL STUDY ON THE BEHAVIOR OF ALKALI METAL DURING THE COMBUSTION OF ZHUNDONG COAL

03011328 Yang Xu

Supervised by Changdong Sheng

Abstract:Zhundong coal is known for its high sodium content. It can cause severe slagging and fouling problems as well as much particulate matter generation during its combustion. According to this, we take the coal in Wucaiwan for a sample. The experiment of the conversion of Zhundong coal is carried out in the one-dimension down-fired furnace, after which the particulate matter is collected. By analyzing the particulate matter, we can study the formation characteristics of particles in different atmosphere. What’s more, we can also change the size of the coal powder, the concentration of oxygen or add kaolin into the coal to study what influence they will have on the formation of fine particulate matter.

During the Study, we find that Zhundong coal is rich in Moisture and volatile. The amount of Ca, Mg, and Na is very high in the coal. We can find two maximum points in the curves of the quality- size distribution of particulate matter, which stand for two different mechanisms of the particulate formation. They are Evaporation, nucleation and condensation mechanism and fragmentation, melting mechanism. We can find much more submicron particulate matter in the atmosphere of pyrolysis compared to the atmosphere of combustion and gasification in CO₂. The higher concentration of oxygen means higher combustion temperature, which can lead to more submicron particulate matter formation and the maximum point of PM₁ shifting to larger particles. We can find that the ultra micron particulate matter also increase in this case. The results of the IC on the Water soluble substances of the particulate matter from DLPI show that content of the alkali metal sulfate and chloride content is very high in submicron particulate matter, which means alkali metal do much contribution to the formation of submicron particulate matter. Last but not the least, adding kaolin into Zhundong coal can decrease the yield of particulate matter (both submicron and ultra micron) to some extent in the atmosphere of pyrolysis, combustion and gasification in CO₂.

Key words: Zhundong coal, alkali metal behavior, down-fired furnace, fine particulate matter

目 录

第一章 绪论 1

1.1 课题研究背景 1

1.1.1 我国的煤炭消费现状 1

1.1.2 PM_2.5的危害 1

1.2 准东高钠煤简介 2

1.3 国内外研究现状 3

1.4 本文的研究目的和研究内容 4

1.5 本章小结 5

第二章 燃烧实验系统与颗粒物样的测量方法 6

2.1 引言 6

2.2 样品制备 6

2.3 煤样的基础分析 6

2.3.1 工业分析 6

2.3.2准东煤灰成分分析 6

2.4 一维沉降炉实验 7

2.4.1纳博热沉降炉实验台 7

2.4.2旋风分离器 9

2.4.3 低压撞击器（DLPI） 10

2.5 X-射线衍射分析（XRD） 10

2.6 离子色谱分析（IC） 11

2.7 扫描电镜分析（SEM） 12

2.8 本章小结 12

第三章 实验结果与讨论 13

3.1 引言 13

3.2 一维沉降炉实验 13

3.2.1 细颗粒物生成特性 13

3.2.2 XRD分析结果 16

3.2.3 IC（离子色谱分析）结果 19

3.2.4 SEM电镜扫描结果 20

3.3本章小结 21

第四章 结论与展望 23

致 谢 24

参考文献(References) 25

第一章 绪论

1.1 课题研究背景

1.1.1 我国的煤炭消费现状

中国是一个产煤大国，煤炭在我国国民经济中有着举足轻重的地位（如图1-1）。我国煤炭的消费主要在重工业领域以及电力行业，也就是火力发电厂。虽然近年来国家一直在提倡发展太阳能、风能、核能等新型清洁能源，但是，因为技术经济性的限制，更重要的是当下没有一种能源能够取代燃煤的稳定性，煤炭在中国的能源消费市场上仍然有着不可替代的地位。就发电领域来讲，虽然太阳能电站、风力发电站、水电站、核电站等近年来发展势头良好，但传统的火力发电仍然是主力，约占整个市场的70%-80%（如图1-2）。

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