多级吸附再生双流化床气固流动特性研究

论文总字数：29167字

摘 要

随着全球变暖问题日趋严重，CO₂的排放问题一直是社会各界关注的焦点。而燃煤电厂作为CO₂排放的重点部门之一，同时供给着国家能源的命脉。如何有效减少排放而又不影响产能，逐渐成为值得研究者们关注和探究的问题。燃烧后的CO₂补集技术因为可靠地脱碳能力和不需要大幅改造燃烧设备而得到广泛的关注，在这其中，碱金属吸收剂化学吸收CO₂的技术因为效率高、解离和再生能耗低、环保无污染等优势，成为了目前的研究热点。但由于目前的实现碱金属吸收剂脱碳及再生的设备尚不理想，这在大大限制了其在工业上的应用。

因此，本文搭建的双级鼓泡床-输运床耦合反应器，同时兼顾了鼓泡流化床气固接触时间长和循环流化床固体循环率高的两大优点，并能通过独立调节各项参数，完成对气固接触时间和固体循环率的控制。为探究其运行工况，本文基于该系统的气固流动特性作了如下研究：

设计并进行了系统的冷态实验，探究碳酸化反应器一级鼓泡床布风板出口压力波动与第一级、第二级鼓泡床静止床高的关系，实验发现：总床高越高，压力波动越大；总床高一定时，二级鼓泡床高度越高，压力波动越小。并对系统输运量进行了标定，作图分析其随各参数的变化趋势。并得到了以下结论：系统输运量与中心风量、鼓泡床高度同向增减。

同时，还在冷态实验中对对级间、床间返料量进行了标定，研究了各参数对级间、床间返料量的影响，得出了以下结论：级间、床间返料量受松动风量影响较大，几乎是线性增长关系，受返料风、第二级床高影响较小。

此外，本文还对该系统进行了热态试验，并得到了合格的脱碳效率和出口烟气CO₂浓度，以此说明本系统的脱碳能力和循环再生能力，对日后工业运用有一定价值。

关键词：碳捕集，双级鼓泡床连续脱碳系统，碱金属基干法，鼓泡床气固流动特性

Abstract

As the problem of global warming becomes more and more serious, the issue of CO2 emissions has always been the focus of attention from all walks of life. Coal-fired power plants, as one of the key sectors of CO2 emissions, also supply the lifeline of national energy. How to effectively reduce emissions without affecting production capacity has gradually become a problem that researchers should pay attention to and explore. The CO2 replenishment technology after combustion has received extensive attention due to its reliable decarburization capability and the need to significantly modify the combustion equipment. Among them, the alkali metal absorbent chemically absorbs CO2 because of high efficiency, low dissociation and regeneration energy consumption. The advantages of environmental protection and pollution-free have become the current research hotspots. However, the current equipment for decarburization and regeneration of alkali metal absorbents is not ideal, which greatly limits its industrial application.

Therefore, the two-stage bubble-bed transport reactor constructed in this paper takes into account the two advantages of long gas-solid contact time of the bubbling fluidized bed and high solids circulation rate of the circulating fluidized bed, and can be independently adjusted. The parameters control the gas-solid contact time and the solids circulation rate. In order to explore its operating conditions, this paper makes the following research based on the gas-solid flow characteristics of the system:

The cold state experiment of the system was designed and carried out to investigate the relationship between the outlet pressure fluctuation of the first-stage bubbling bed of the carbonation reactor and the static bed height of the first-stage and second-stage bubbling beds. The experiment found that the total bed height was higher. High, the pressure fluctuation is greater; when the total bed height is constant, the higher the level of the secondary bubbling bed, the smaller the pressure fluctuation. The system's transport volume was calibrated, and its trend with various parameters was analyzed. And got the following conclusion: the system transport volume and the central air volume, bubbling bed height increase and decrease in the same direction.

At the same time, the amount of feed between the stages and between the beds was also calibrated in the cold experiment. The influence of each parameter on the amount of feed between the stages and between the beds was studied. The following conclusions were drawn: interstage and bed back The amount of material is greatly affected by the loose air volume, which is almost linear growth, and is less affected by the return air and the second stage bed height.

In addition, the thermal test of the system was carried out, and the qualified decarburization efficiency and CO2 concentration of the flue gas were obtained. This shows that the decarbonization capacity and cycle regeneration capacity of the system have certain value for future industrial application.

Key words: carbon capture, two-stage bubbling bed continuous decarburization system, alkali metal-based dry method, gas-solid flow characteristics of bubbling bed

目 录

摘要 ……………………………………………………………………………………………………………………………………Ⅰ

Abstract …………………………………………………………………………………………………..…..………………… Ⅱ

1. 绪论 ……………………………….......………………………………………………………………………………1
   1. 课题研究背景及意义 …………………….......…………………………………………………………1

1.1.1温室气体排放现状及危害 .........................................................………………………1

1.1.2 世界碳减排形式与政策 ..................................................................................1

• 1. 二氧化碳捕集及封存技术介绍 .....................................……………………………………2
     1. 碳捕集技术分类 ....................................................................………………………2
     2. 燃烧前捕集技术 .............................................................................................3
     3. 燃烧中捕集技术 .............................................................................................3
     4. 燃烧后捕集技术 .............................................................................................4
  2. 碱金属基干法脱除CO2 ........................................………………………………………………5

1.3.1国外的研究现状 ..........................................................................................6

1.3.2国内的研究成果 ..........................................................................................8

• 1. 本文研究的目的和内容 ........................................................................................10
  2. 本章小结 .................................................................................................................11

1. 实验装置、方法 .....................................................................................................12

2.1 实验物料 ................................................................................................................12

2.2 实验装置 ...............................................................................................................12

2.2.1 碳酸化反应器 .............................................................................................13

2.2.2 再生反应器 .................................................................................................13

2.2.3 旋风反应器 .................................................................................................13

2.2.4 返料阀 .........................................................................................................13

2.3 实验原理 ...............................................................................................................14

2.4 实验设计 ...............................................................................................................14

2.4.1 冷态试验设计 ..............................................................................................14

2.4.2 热态试验设计 ..............................................................................................15

2.5 本章小结 ...............................................................................................................16

第三章 输运量标定极其变化规律分析 ...............................................................................17

3.1 床层高度变化对于第一级鼓泡床布风板出口压力波动的影响 .........................17

3.2 床层高度和中心风量对输运量的影响 .................................................................19

3.2.1 床层高度对于物料输运量的影响 ...............................................................19

3.2.2 中心风量对于物料输运量的影响 ...............................................................20

3.3 本章小结 ...............................................................................................................20

第四章 返料器标定及其变化规律分析 ...............................................................................21

4.1 床间返料器的标定 ................................................................................................21

4.1.1 床间返料器松动风量对返料量的影响 ......................................................21

4.1.2 床间返料器返料风量对返料量的影响 ......................................................22

4.1.3 第二级鼓泡床静止床高对床间返料器返料量的影响 ..............................23

4.2 级间返料器的标定........................................................................................................23

4.2.1 级间返料器松动风量对返料量的影响 ......................................................23

4.2.2 级间返料器返料风量对返料量的影响 .......................................................24

4.2.3 第二级鼓泡床静止床高对级间返料器返料量的影响 ...............................24

4.3 本章小结 ...................................................................................................................25

第五章 热态全循环试验流程及结果分析 ..........................................................................26

5.1 热态全循环试验流程 ..............................................................................................26

5.2 热态脱碳效率计算方法 ..........................................................................................26

5.3 热态试验结果及分析 ..............................................................................................27

5.4 本章小结 ..................................................................................................................30

第六章 全文总结 ..................................................................................................................31

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