平朔煤与生物质共燃烧实验研究

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3.0 赵德峰 2024-11-11 18 4 3.1MB 59 页 15积分

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摘要

化石能源的大量消耗造成了严重的能源危机，同时也带来了严重的环境问题。

煤炭是我国的主要基础能源，在燃烧过程中释放出大量烟尘、SOx、NOx及温室气

体CO2，致使我国环境呈典型的煤烟型污染，造成了严重的经济损失。平朔煤是我

国典型的动力用煤，研究其高效、清洁燃烧利用技术，以及开发利用可再生能源

意义重大。生物质是可再生能源的一种，具有其他矿物燃料不可比拟的优势，是

替代或补充化石燃料的理想能源。在此背景基础下，本文对平朔煤与生物质进行

了共热解和共燃烧实验研究，考察掺混生物质对平朔煤热解特性和燃烧特性的影

响，以期为平朔煤的高效、清洁燃烧利用技术的开发与应用提供理论依据和参考。

本文首先介绍了生物质的性质、特点及利用技术，分析了生物质在直接利用

过程中存在的问题，进而提出了煤与生物质共热解和共燃烧技术，介绍了煤与生

物质共燃烧的意义、主要方式和研究现状，阐明了本课题的研究意义和重要性。

考虑到热解是燃烧过程中不可避免经历的步骤，研究煤的热解特性，对后续

的煤的燃烧利用具有关键性作用。因此，本文对平朔煤和生物质进行了共热解实

验，考察了掺混不同生物质以及掺混不同比例的生物质时平朔煤的热解特性，得

到了混合样品的热解特征参数。另外，将平朔煤和生物质混合热解的实际失重速

率曲线图与折算后的曲线图进行了参照对比。最后，利用一级反应动力学模型和

Coats-Redfern 积分法求得平朔煤与生物质混合样品的动力学参数。从热解特征参

数、实际失重速率曲线和折算后曲线的对比图以及动力学参数的结果来看，平朔

煤与生物质共热解过程中存在协同效应，生物质对平朔煤的热解具有促进作用。

利用热重分析仪对不同掺混比例的平朔煤和生物质混合半焦进行了燃烧实

验，分析了不同工况下平朔煤半焦的燃烧特性。从混合半焦的燃烧特征参数来看，

平朔煤与生物质混合半焦的着火温度和燃尽温度随生物质掺混比例的增加而降

低，同时混合半焦的着火稳燃特性指数和综合燃烧特性指数也相应增大，混合半

焦的燃烧性能得到改善。此外，在本研究范围内，当生物质掺混比例为70%时，混

合半焦的最大燃烧速率值最大，而且其着火特性、燃烧特性以及燃尽特性对较好。

总的来说，掺混生物质能够明显改善混合半焦的着火性能和燃烧性能。

在热天平实验研究的基础上，利用 Coats-Redfern 积分法和一级反应动力学模

型求解了平朔煤与生物质混合半焦的燃烧动力学参数。结果表明生物质的燃烧活

化能要比平朔煤的燃烧活化能小，而且随着生物质掺混比例的增大，平朔煤与生

物质混合半焦的燃烧活化能逐渐降低，说明掺混生物质对提高平朔煤与生物质混

合半焦的燃烧反应活性是有利的，掺混生物质能够改善混合半焦的燃烧特性。

关键词：平朔煤生物质共热解共燃烧热重分析反应动力学

ABSTRACT

Due to the global environmental concerns over excessive fossil fuel usage, the new

and clean energy has been searched to substitute for fossil resources. Compared with

petroleum and natural gas, which are in deeper and deeper shortages, the amount of coal

deposit is abundant. Coal, as a traditional fossil fuel, will still be a major energy source

in the foreseeable future throughout the world, especially in China.

Pingshuo coal is a typical thermal coal in China, which characteristically has a

high content of sulfur and chlorine. Because of the great amount of SOx, NOx and CO2

emission during the direct combustion of coal, it is highly important to develop more

effective, efficient technology to clean utilize coal.

As we know, biomass is one of the most important renewable energy resources,

and its application becomes more and more significant for climate protection. Compared

with other renewable energy resources, biomass is abundant in annual production, with

a geographically widespread distribution in the world. The application of biomass as

energy source can lead to a zero net CO2 emission in a very short life cycle period, since

carbon in the form of CO2 and energy are fixed by photosynthesis during biomass

growth. Consequently, the co-utilization of biomass in the existing coal-fired plants is

very appealing nowadays.

Thus, the co-combustion experiments of Pingshuo coal&biomass were conducted

against the background. Then it can be found that biomass plays an important role

during their co-pyrolysis and co-combustion process. Besides, its high thermochemical

reactivity and high volatile matter yield facilitate the conversion and upgrading of the

fuel mixture.

The characteristics and utilization ways of biomass were firstly summarized and

the current and future developments of biomass fuel conversion technologies were

analyzed in the paper. Then, the significance, main approaches and research status of

coal/biomass co-combustion and co-pyrolysis were introduced in detail. Therefore, it is

highly significant to do this work.

It is well-known that pyrolysis is the first conversion step during coal and biomass

combustion and gasification processes. The pyrolysis plays a key role in clean coal

utilization because of its effects on the resulted char characteristics and process

properties. Therefore, the co-pyrolysis and co-combustion processes of Pingshuo

coal/biomass are the focuses of this research. The pyrolysis behaviors of Pingshuo coal

and biomass had been investigated using a thermo-gravimetric analyzer and more

attention was paid to the pyrolysis characteristics and kinetic parameters of their blends.

Moreover, the comparison between the experimental and the calculated DTG curves

shows that the co-pyrolysis process is not the simple sum of the pyrolysis weight loss

rate of Pingshuo coal and the biomass. At last, the activation energy and the frequency

factor of the co-pyrolysis were calculated by Coats-Redfern method and the first-order

reaction model. The results show that the activation energy and the frequency factor

change with the mixture ratio of the biomass and the regularity was consistent with the

above-mentioned conclusions. Therefore, it can be deduced that there exist synergetic

effects between the biomass and Pingshuo coal during their co-pyrolysis process.

The combustion behaviors of Pingshuo coal and biomass mixed char were

investigated using TG analyzer. The effects of different pyrolysis conditions on the

combustion characteristics of Pingshuo coal char, as well as the addition ratio of

biomass were analyzed. The ignition temperature and the burnout temperature of the

mixed char are lower than those of Pingshuo coal char. The ignition temperature and the

burnout temperature of the mixed chars decrease with the increase of biomass mixture

ratio. Thus, the ignition performance and the burnout performance of the mixed char

increase compared with those of Pingshuo coal char. Furthermore, the maximum

combustion rate of the mixed char increases and the corresponding temperature

decreases with the increase of the biomass mixture ratio. Moreover, compared with

other chars (except biomass char) employed in the research, the combustion rate of the

mixed char with the biomass blending ratio of 70 wt % is the highest. In addition, the

ignition performance, the burnout performance, the ignition characteristic index and the

combustion characteristic index are also better than those of other chars. This result

suggests that the addition of the biomass can facilitate the combustion process, and

there is an optimal blending proportion during the whole combustion process.

On the basis of the results of the thermo-gravimetric experiments, the combustion

kinetic parameters of Pingshuo coal and biomass mixed char has been calculated with

good correlation using Coats-Redfern method and a first-order reaction model. It can be

obviously seen that the activation energy of biomass char is lower than that of Pingshuo

coal char and the biomass char has a higher reactivity. In addition, along with the

change of the biomass mixture ratio, the activation energy and the frequency factor of

the mixed char vary regularly. The activation energy of the mixed char lies between that

of biomass char and Pingshuo coal char. The larger the mixture ratio of the biomass is,

the lower the activation energy of the mixed char is. It can be concluded that the

addition of the biomass can facilitate the burning process of the mixed char.

Key Word ：Pingshuo coal, biomass, co-pyrolysis, co-combustion,

thermogravimetric analysis, kinetics

中文摘要

ABSTRACT

第一章文献综述及选题..........................................................................................1

§1.1 前言....................................................................................................................1

§1.2 煤与生物质共转化利用....................................................................................4

§1.3 煤与生物质共热解转化利用技术....................................................................5

§1.4 煤与生物质共燃烧转化利用技术....................................................................6

§1.4.1 煤与生物质共燃烧的研究意义...............................................................6

§1.4.2 煤与生物质共燃烧的主要方式 ...............................................................6

§1.4.3 煤与生物质共燃烧的研究现状 ...............................................................7

§1.5 选题的立论依据和研究内容........................................................................8

§1.5.1 课题立论依据..........................................................................................8

§1.5.2 研究内容..................................................................................................9

第二章实验装置及测试方法 ................................................................................ 11

§2.1 实验样品...........................................................................................................11

§2.1.1 原料样品................................................................................................ 11

§2.1.2 半焦实验样品的制备 ............................................................................ 11

§2.2 实验装置..........................................................................................................13

§2.2.1 管式固定床反应炉制焦实验装置 .........................................................13

§2.2.2 热天平实验装置 ....................................................................................14

§2.3 实验方案..........................................................................................................16

§2.3.1 管式固定床反应炉制焦实验.................................................................16

§2.3.2 热天平实验............................................................................................17

§2.3.2.1 热解实验……………………………………………………………..17

§2.3.2.2 燃烧实验……………………………………………………………..17

§2.4 测试方法 ....................................................................................................17

§2.4.1 工业分析................................................................................................17

§2.4.2 元素分析................................................................................................18

§2.4.3 灰分分析................................................................................................18

§2.4.4 灰熔点测试............................................................................................18

§2.5 本章小结 ....................................................................................................19

第三章平朔煤与生物质共热解实验研究 .............................................................20

§3.1 引言 ............................................................................................................20

§3.2 实验步骤 ....................................................................................................20

§3.2.1 实验原料................................................................................................20

§3.2.2 平朔煤与生物质混合样品热解实验 .....................................................20

§3.3 实验结果与讨论.........................................................................................21

§3.3.1 平朔煤与生物质单独热解实验 .............................................................21

§3.3.1 不同掺混比例生物质与平朔煤共热解实验..........................................21

§3.4 平朔煤与生物质混合样品热解反应动力学研究.......................................24

§3.5 本章小结 ....................................................................................................26

第四章平朔煤与生物质混合半焦燃烧特性的实验研究......................................28

§4.1 引言 .............................................................................................................28

§4.2 实验步骤 .....................................................................................................29

§4.2.1 不同热解终温下制得的平朔煤半焦样品..............................................29

§4.2.2 平朔煤与生物质混合半焦样品.............................................................30

§4.2.3 半焦燃烧特性的表征 ............................................................................31

§4.3 不同热解终温下制得的平朔煤半焦的热重实验结果与分析.....................31

§4.4 平朔煤与生物质混合半焦的热重实验结果与分析 ....................................33

§4.4.1 平朔煤焦与生物质焦单独燃烧实验结果与分析 ..................................33

§4.4.2 生物质掺混比例对平朔煤焦燃烧特性的影响......................................34

§4.5 本章小结 .....................................................................................................36

第五章平朔煤与生物质混合半焦的燃烧动力学研究..........................................37

§5.1 引言 .............................................................................................................37

§5.2 半焦燃烧机理函数和反应模型的确定 .......................................................38

§5.2.1 动力学机理函数 ....................................................................................38

§5.2.2 半焦燃烧机理函数和反应模型的选择 .................................................38

§5.3 平朔煤与生物质混合半焦的燃烧动力学参数计算 ....................................40

§5.4 本章小结 .....................................................................................................41

第六章全文总结与展望........................................................................................43

§6.1 全文总结 .....................................................................................................43

§6.2 本文主要创新点..........................................................................................44

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摘要：

摘要化石能源的大量消耗造成了严重的能源危机，同时也带来了严重的环境问题。煤炭是我国的主要基础能源，在燃烧过程中释放出大量烟尘、SOx、NOx及温室气体CO2，致使我国环境呈典型的煤烟型污染，造成了严重的经济损失。平朔煤是我国典型的动力用煤，研究其高效、清洁燃烧利用技术，以及开发利用可再生能源意义重大。生物质是可再生能源的一种，具有其他矿物燃料不可比拟的优势，是替代或补充化石燃料的理想能源。在此背景基础下，本文对平朔煤与生物质进行了共热解和共燃烧实验研究，考察掺混生物质对平朔煤热解特性和燃烧特性的影响，以期为平朔煤的高效、清洁燃烧利用技术的开发与应用提供理论依据和参考。本文首先介绍了生物质的性质...

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