化学链燃烧中金属载氧体的反应特性实验研究

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摘要

化学链燃烧技术的提出，起初是为了提高能源利用效率，后来发现该技术在

CO2减排方面有其独特的优势，随着当今对 CO2等温室气体的关注，化学链燃烧

技术在最近几年有了高速的发展，该技术也被认为是解决能源结构和环境两者之

间矛盾的突破口。

在化学链燃烧技术中，还原-氧化反应特性是载氧体性能中一个非常重要的指

标。本文利用小型流化床实验台，对四种制备金属载氧体 Ni 基、Fe 基、Cu 基和

Co 基在四个不同反应温度（650℃、750℃、850℃、950℃）和两种气氛（CH4、

CO+H2）下进行实验研究。通过分析各个工况下反应产物浓度随时间的变化曲线，

初步对比了四种金属载氧体的反应特性，通过对实验数据的处理，得出载氧体的

还原转化率，进而判断实验过程中温度以及气氛对载氧体的还原反应特性的影响。

实验研究表明，四种制备金属载氧体与 CH4反应时，除了 Cu 基载氧体之外，

其他载氧体的还原转化率均随温度的升高而升高，而且伴随着不同程度的积碳和

烧结；制备 Ni 基载氧体在各个温度下都能表现出较高的活性，其积碳随温度的升

高有减少的趋势；制备 Fe 基载氧体的还原反应活性不高，还原转化率较低；Cu

基载氧体在 750℃时活性最强；在 Co 基载氧体的制备过程中 CoO 与Al2O3生成

了CoAl2O4，致使该载氧体的转化率不是很高；总体而言，以 CH4为燃料时，四

种制备金属载氧体的还原反应活性强弱依次是：Ni 基、Cu 基、Co 基、Fe 基。

当四种制备金属载氧体与模拟煤制气反应时，Co 基载氧体随着温度的升高，

其还原转化率增加不大，其他三种载氧体的还原转化率没有随着温度的升高而升

高，Ni 基的最佳反应温度是 750℃，Fe 基和 Cu 基的最佳反应温度均为 850℃；

总体而言，以模拟煤制气为燃料时，四种制备金属载氧体的还原反应活性强弱依

次是：Ni 基、Cu 基、Fe 基、Co 基。以模拟煤制气为燃料时转化率普遍较高，因

此模拟煤制气比 CH4更适合化学链燃烧。

在实验过程中发现，四种制备金属载氧体均出现了不同程度的积碳现象，抗

积碳能力也是金属载氧体性能研究中一个不可忽视的特性，该性质的优劣决定了

金属载氧体的活性大小。积碳是由于 CH4的热解反应和 CO 的Boudouard 反应

造成的，积碳不仅和温度有关，而且还和压力、载氧体的载氧率等有关，

为了解水蒸气对积碳现象有抑制作用，本文结合热天平和管式炉对四种制备金属

的积碳特性进行研究。本文以 CO 为燃料（即还原性气氛），在热天平上分别对

Ni 基、Fe 基、Cu 基和 Co 基四种制备金属载氧体进行热重实验，通过分析各自

的TG 曲线，了解到四种载氧体均出现了不同程度的积碳现象，其中 Cu 基载氧体

可以在一定程度上抑制积碳。为了避免因积碳而带来的载氧体失活，在管式炉内

进行 CO 和载氧体的燃烧反应时，向炉内通入水蒸气，发现 CO 还原金属载氧体

时，通入水蒸气可以有效的抑制积碳。最后利用 X射线衍射仪（XRD）扫描反应

产物，分析结果显示通水蒸气时 C的特征峰已经消失，进一步验证了水蒸气的抑

碳效果。

关键词：化学链燃烧 CO2减排金属载氧体反应特性

ABSTRACT

Chemical-looping combustion (CLC) was proposed as a combustion technology

for efficient utilization of the energy. Later, it is generally acknowledged that the

technology has an unique advantage in CO2emission reduction. With inherent

separation of the greenhouse gas CO2, the technology has been developed so much in

recent years and it is an effective method to solve the conflict between energy structure

and environment.

One important index of the oxygen carrier performance is the characteristic of

reduction-oxidation in Chemical-looping combustion. In this paper, the fluidized bed is

used to study on four prepared metal oxygen carriers (Ni-based, Fe-based, Cu-based

and Co-based) at different reaction temperature of 650℃,750℃,850℃,950℃and in

the atmosphere of CH4and CO+H2. Through analyzing the variation of the reaction

product concentration along with time, the reactivity of the prepared metal oxygen

carriers was compared. The conversion ratio in the reduction can be calculated through

dealing with the experimental data. And then, the effects of temperature and

atmosphere on the reactivity of oxygen carriers were analyzed.

When the prepared metal oxygen carriers reacted with CH4, the experimental data

reveal that their reduction ratio increases with the rise of the temperature and at the

same time, carbon deposition and sintering were found. The Ni-based oxygen carriers

react rapidly with CH4at each temperature, and the carbon deposition decreases with

the rise of temperature. The Fe-based oxygen carriers react slowly with CH4and its

conversion ratio is small. The Cu-based oxygen carriers are not suitable for reacting

with CH4at low temperature. The Co-based oxygen carriers’ conversion ratio is also

not high, because the CoO reacts with Al2O3and products CoAl2O4. In general, the

intensity order of the reduction reactivity at the atmosphere of CH4is: Ni-based,

Cu-based, Co-based, Fe-based.

At the atmosphere of CO+H2, The Co-based oxygen carriers’ conversion ratio

increases slightly with the rise of the temperature while the other three oxygen carriers’

conversion ratio does not increase. The optimum reaction temperature of Ni-based

oxygen carriers is 750℃while that of the Fe-based oxygen carriers and the Cu-based

oxygen carriers are both 850 ℃. In general, the intensity order of the reduction

reactivity at the atmosphere of CO+H2is: Ni-based, Cu-based, Fe-based, Co-based.

Compared with the two kinds of atmosphere, it is found that CO+H2is more suitable

for the chemical-looping combustion.

In the experiment, carbon deposition and sintering were found. In the

chemical-looping combustion(CLC) technology, the anti-carbon capability of the metal

oxygen carrier can not be ignored, which decides the activity of the oxygen carrier.

Carbon deposition, which is caused by CH4pyrolysis and Boudouard reactions,

depends on the temperature as well as the pressure and the amount of oxygen added

with the oxygen carriers. In order to understand the inhibiting effect of H2O on carbon

deposition, thermobalance and tube furnace were used to study on the carbon

deposition of four prepared metal oxygen carriers. In this paper, Thermal Gravimetric

Analysis (TGA) is used to study on Ni-based 、Fe-based 、Cu-based and Co-based

prepared oxygen carriers, using CO as the fuel. TG curves indicate that the carbon

deposition characteristics of different prepared oxygen carriers occur and the Cu-based

oxygen carriers can restrain carbon deposition to some extent. Water steam was added

into the tube furnace, which can restrain carbon deposition effectively during CO

reacting with oxygen carriers. Finally, X-Ray Diffraction (XRD) was used to scan the

reaction product. Results show that the characteristic peaks of carbon disappeared

when adding water steam into the furnace, which confirms the inhibitory effect of

water steam on carbon deposition.

Key Word ：chemical-looping combustion (CLC), CO2emission

reduction, oxygen carrier, carbon deposition characteristics

中文摘要

ABSTRACT

第一章绪论 ......................................................... 1

§1.1 引言 ........................................................ 1

§1.2 本课题研究的意义 ............................................ 1

§1.3 化学链燃烧技术的发展现状 .................................... 4

§1.3.1 化学链燃烧技术的原理和特点 ............................ 4

§1.3.2 化学链燃烧技术国内外的研究进展 ........................ 5

§1.4 本文的主要研究内容 ......................................... 9

第二章实验系统及实验方法 ........................................... 11

§2.1 流态化原理 ................................................ 11

§2.2 实施方案介绍 ............................................... 12

§2.3 实验样品介绍 ............................................... 12

§2.4 实验用载氧体的制备方法介绍 ................................. 13

§2.5 实验设备介绍 ............................................... 14

§2.5.1 小型流化床试验台 ..................................... 14

§2.5.2 小型流化床的调试 ..................................... 15

§2.5.3 红外煤气分析仪 ....................................... 15

§2.6 本章小结 ................................................... 15

第三章金属载氧体的反应特性研究 ..................................... 17

§3.1 实验流程和工况 ............................................ 17

§3.1.1 还原性实验流程 ....................................... 17

§3.1.2 氧化性实验流程 ....................................... 17

§3.1.3 实验工况 ............................................. 17

§3.2 还原性气体和金属载氧体反应的热力学判据 .................... 18

§3.3 实验数据处理方法 .......................................... 19

§3.4 实验结果及分析 ............................................ 20

§3.4.1 CH4为还原气氛 ........................................ 20

§3.4.2 CO+H2为还原气氛 ...................................... 32

§3.4.3 CH4和 CO+H2两种气氛的比较 ............................. 43

§3.5 本章小结 .................................................. 44

第四章金属载氧体的积碳特性研究 .................................... 45

§4.1 实验流程及工况 ............................................ 45

§4.2 实验结果及分析 ............................................ 46

§4.2.1 四种金属载氧体的积碳特性分析 ......................... 46

§4.2.2 水蒸气对四种金属载氧体积碳特性的影响 ................. 47

§4.3 实验后载氧体的 XRD 分析 .................................... 48

§4.4 本章小结 .................................................. 51

第五章总结 ......................................................... 52

§5.1 本文主要工作及研究结论 .................................... 52

§5.2 本文创新点 ................................................ 53

§5.3 后续工作展望 .............................................. 53

参考文献 ............................................................ 55

在读期间公开发表的论文和承担科研项目及取得成果 ...................... 60

致谢 .............................................................. 61

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摘要：

摘要化学链燃烧技术的提出，起初是为了提高能源利用效率，后来发现该技术在CO2减排方面有其独特的优势，随着当今对CO2等温室气体的关注，化学链燃烧技术在最近几年有了高速的发展，该技术也被认为是解决能源结构和环境两者之间矛盾的突破口。在化学链燃烧技术中，还原-氧化反应特性是载氧体性能中一个非常重要的指标。本文利用小型流化床实验台，对四种制备金属载氧体Ni基、Fe基、Cu基和Co基在四个不同反应温度（650℃、750℃、850℃、950℃）和两种气氛（CH4、CO+H2）下进行实验研究。通过分析各个工况下反应产物浓度随时间的变化曲线，初步对比了四种金属载氧体的反应特性，通过对实验数据的处理，得出载氧...

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