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毕业论文网 > 毕业论文 > 理工学类 > 能源与环境系统工程 > 正文

污泥与生物质催化共热解动力学分析毕业论文

 2022-01-09 17:59:49  

论文总字数:31286字

摘 要

为了探索高效的城市污泥处理技术,解决传统城市污泥处理方法中产生的污染问题,本文针对污泥与生物质催化共热解过程的热解特性及动力学特性展开分析。

本文选用城市污泥和松木屑作为样品,用同步热分析仪进行工业分析和元素分析。探究松木屑不同添加量条件下污泥与松木屑的共热解特性,研究添加10%氧化钙作为催化剂时的共热解特性。针对动力学研究,采用Coats-Redfern积分法,选择有效的机理函数,通过软件绘制出拟合曲线,解出对应的动力学参数,剖析动力学规律。主要结论有:

热解特性研究发现,污泥热解顺序为:挥发水分、分解小分子有机物、分解高分子化合物、结焦反应。木屑添加量从0%到100%,热解特性指数从1.12上升到29.55,提高了共热解的强度和效率。氧化钙的加入降低了反应速率,总体抑制反应进程,但从DTG曲线看,700℃时出现失重率大约为10%的失重峰,对结焦反应阶段有促进作用,体现了氧化钙的选择性催化。

动力学特性研究发现,共热解过程中污泥超过50%时,热解过程以转化率α为依据可以分成三个区间:0.1–0.55、0.55–0.75和0.75–0.95。低于50%时分为两个区间:0.1–0.75和0.75–0.95。α在0.55-0.75之间的活化能很小,高分子化合物分解率低。共热解能够降低反应中的活化能,提高反应效率,木屑比例越大,总活化能越大,但比污泥及木屑单独热解的活化能小。催化剂的加入改变了共热解特性,使共热解过程需要的总活化能增大,抑制了反应的进行,但在α=0.75-0.95范围内的活化能减小,即氧化钙的催化作用促进了高温阶段的反应。

关键词:城市污泥 生物质 热解动力学 催化剂

Kinetic analysis of catalytic pyrolysis of sludge and wood chips

Abstract

In this paper, urban sludge and pine wood chips are selected as samples, and industrial analysis and elemental analysis are carried out with a synchronous thermal analyzer. To explore the co-pyrolysis characteristics of sludge and pine wood chips under different pine wood chips addition conditions, and to study the co-pyrolysis characteristics when adding 10% calcium oxide as a catalyst. For the study of dynamics, the Coats-Redfern integration method is used to select an effective mechanism function, draw a fitting curve through the software, solve the corresponding dynamics parameters, and analyze the dynamics laws. The main conclusions are:

Pyrolysis characteristics study found that the sludge pyrolysis sequence is: volatile water, decomposition of small molecular organic compounds, decomposition of high molecular compounds, coking reaction. The addition amount of wood chips is from 0% to 100%, and the pyrolysis characteristic index increases from 1.12 to 29.55, which improves the strength and efficiency of co-pyrolysis. The addition of calcium oxide reduces the reaction rate and generally inhibits the progress of the reaction, but from the DTG curve, a weight loss peak of about 10% occurs at 700 ° C, which promotes the coking reaction stage and reflects the selective catalysis of calcium oxide .

The kinetic characteristics study found that when the sludge exceeds 50% during the co-pyrolysis process, the pyrolysis process can be divided into three intervals based on the conversion rate α: 0.1–0.55, 0.55–0.75, and 0.75–0.95. When it is less than 50%, it is divided into two intervals: 0.1–0.75 and 0.75–0.95. The activation energy of α between 0.55-0.75 is very small, and the decomposition rate of polymer compounds is low. Co-pyrolysis can reduce the activation energy in the reaction and improve the reaction efficiency. The greater the proportion of wood chips, the greater the total activation energy, but it is smaller than the activation energy of pyrolysis of sludge and wood chips alone. The addition of the catalyst changes the characteristics of co-pyrolysis, increases the total activation energy required for the co-pyrolysis process, and inhibits the progress of the reaction, but the activation energy decreases in the range of α = 0.75-0.95, which promotes the reaction at high temperature stage .

Key words:Sewage sludge; Biomass; Kinetics; Catalyst

目 录

摘要 I

Abstract II

第一章 绪论 1

1.1课题背景 1

1.2 污泥来源及组成特性 2

1.3 污泥处理方法 3

1.3.1 填埋处理 3

1.3.2 堆肥处理 3

1.3.3 材料化处理 4

1.3.4 热处理 4

1.4研究进展 5

1.4.1 热解技术原理 5

1.4.2 污泥热解/共热解特性研究进展 6

1.4.3 污泥催化热解特性研究进展 7

1.5 本文的研究内容和技术路线 8

第二章 实验原料及理化特性分析 11

2.1 引言 11

2.2 实验仪器 11

2.3 分析方法 11

2.3.1 工业分析 11

2.3.2 元素分析 11

2.4 结果与讨论 12

2.5 本章小结 12

第三章 污泥和木屑催化共热解特性研究 15

3.1 引言 15

3.2 实验过程 15

3.3 分析方法 15

3.4 结果与讨论 15

3.4.1 污泥与木屑共热解特性 15

3.4.2 污泥与木屑催化共热解特性 19

3.5 本章小结 24

第四章 城市污泥与木屑催化共热解动力学特性 25

4.1 引言 25

4.2 动力学假设和方程 25

4.3 动力学参数算法 26

4.4 结果与讨论 27

4.4.1 污泥单独热解动力学特性 27

4.4.2 污泥与木屑共热解动力学特性 30

4.4.3 污泥与木屑催化共热解动力学特性 31

4.5 本章小结 32

第五章 结论与展望 35

5.1 结论 35

5.2 展望 36

参考文献 37

致谢 41

第一章 绪 论

1.1课题背景

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