论文总字数：22850字

摘 要

高压水洗是目前生物甲烷脱碳的有效途径之一，但是采用喷淋塔传质效率较低，溶剂循环流量大，导致设备、管道体积较大，占地面积多，同时直接运行费用包括电耗、溶剂消耗较高，极大的增加了生产成本。微型化发展是化工发展的崭新方向。微化工技术包括微热、微反应、微分离、微分析等系统。微通道技术是微化工的关键技术之一。微通道具有界面面积增加、传热过程得到强化、传质过程得到强化、所需原料减少、性能安全、“数量放大”六大优势。

本文采用微通道混合器进行气液混合加压脱碳研究。首先以交叉型微混合器、高压注射泵、气体流量计、气液分离罐及相关管路阀门构建了一套实验室脱碳装置。随后以去离子水为脱除溶剂，探究了操作压力、进气流速、操作温度、出气流速和再生水对模拟混合气中CO₂脱除率的影响。结果表明：微通道混合器可明显提高传质效率，操作压力的增大，进气流速和出气流速的降低，温度的下降会提高CO₂的脱除率当操作压力为1.1Mpa，其最大气液比达到29.17：1，约是传统高压水洗法最大气液比的7倍，从而增加脱碳效率。单位体积水对CO₂的吸收量为4.817 mL/mL，可将混合气体中初始时CO₂的含量从45%降至3%以下，此时CO₂的脱除率达到99.052%。流出气内CO₂的百分比含量由进气流速的增加而逐渐减少，穿透时间逐渐提前。随着进气流速125 mL/min增加至200 mL/min，穿透时间由70min提前至40min。同时研究发现低温有利于脱除CO₂，当水温为6.5℃，操作压力为0.75Mpa，气液比为25:1时，即可达到常温下1.1Mpa时的脱碳效果。出气流速不易过大，过大会导致微通道装置脱除CO₂的效率显著下降。通过将气液分离罐中的吸收水减压放出后静置、释放CO₂，将其再生并回用于脱碳，结果表明脱碳效果良好，单位体积水对CO₂的吸收量为4.812 mL/mL，穿透时间保持不变，80min时CO₂脱除率为97.775%，均与使用正常去离子水时无显著差别。

以上研究结果表明：通过微通道混合器可以提高脱碳的传质效率，使得吸收反应相对容易控制，极大提高脱碳能力，从而减少脱碳装置的体积和能耗，在沼气脱碳方面具有潜在的应用前景。

关键词：沼气 CO₂ 高压水洗 微通道

Abstract

High-pressure washing is one of the effective methods of marsh gas decarburization, but the efficiency of mass transfer by spray tower is low. Solvent circulation flow results in equipment, piping larger, covers an area of more, while direct operating costs, including power consumption, solvent consumption is high, greatly increased production costs.Miniaturization of the development of chemical industry is a new direction. Micro-chemical technology, including micro-heat, micro-reaction, micro-separation, micro-analysis and other systems. Microchannel technology is one of the key technologies of micro-chemical industry.

In this paper, using micro-channel mixer for gas-liquid mixture decompression research. First, a set of laboratory decarburizing unit was constructed by a cross-type micro-mixer, a high-pressure injection pump, gas flow meters, a gas-liquid separation tank, related pipeline valves and recycled water. Then, using deionized water as the only solvent to investigate the effect of operating pressure, inlet gas flow rate, operating temperature and outlet flow velocity on CO₂ removal rate in simulated mixture. The results show that the micro - channel mixer can improve the mass transfer efficiency obviously. Increasing pressure and reducing intake air velocity ,outlet flow rate and temperature will increase CO2 removal rate .When the operating pressure is 1.1Mpa, the maximum gas - liquid ratio is 29.17: 1, which is about 7 times of the maximum gas - liquid ratio of the traditional high - pressure water washing method. The amount of CO₂ absorbed per unit volume of water was 4.035 mL / mL and the CO₂ content in the mixed gas reduced from 45% to below 3%, and the removal rate of CO₂ was 99.052%.The percentage of CO2 in the effluent is gradually reduced by the increase of the inlet flow rate, and the penetration time is gradually advanced. With the inlet flow rate of 125 mL / min increased to 200 mL / min, penetration time from 70min advance to 40min.At the same time, it was found that the low temperature was beneficial to remove CO₂. When the water temperature was 6.5 ℃ and the operating pressure was 0.75Mpa, the decarburization effect was as the same as the operating pressure was 1.1Mpa at room temperature. The flow rate of the outlet is not too large, and the efficiency of the CO2 removal of the microchannel device is significantly reduced. The results show that the decarburization effect is good, and the amount of CO2 absorbed per unit volume of water is 4.812 mL / mL, and the amount of CO2 absorbed per unit volume of water is 4.812 mL / mL. , The permeation time remained unchanged, and the CO2 removal rate was 97.775% at 80 min, and there was no significant difference with normal deionized water.

The micro-channel mixer can improve the decarburization mass transfer efficiency and the decarburization capacity, thereby reducing the decarburization device volume and energy consumption, so it has potential application prospects.in the marsh gas decarburization.

Key Words: Marsh gas; Carbon dioxide; High-pressure washing; Micro-channel

目录

摘 要 I

Abstract II

第一章 文献综述 1

1.1背景 1

1.1.1沼气和生物甲烷的性质及优势 1

1.2常用除碳方法 1

1.2.1低温分离法 1

1.2.2吸附分离法 1

1.2.3膜分离法 2

1.2.4溶剂吸收法 2

1.3微通道技术 3

1.3.1微通道反应器的优势 4

1.3.2微通道反应器内气液两相的传质特点 4

1.4本文的研究目标与内容 6

第二章 材料与方法 7

2.2 实验器材 8

2.3 实验方法 8

2.3.1去离子水预处理 8

2.3.2 实验流程 8

2.3.3 微通道混合器加压水洗脱碳的研究 9

2.4 检测和评价手段 10

2.4.1 CO₂的百分比含量的测定 10

2.4.2 各个时间段CO₂脱除率的计算 10

2.4.3 各个时间段单位体积去离子水对CO₂吸收量的计算 10

2.5 误差分析 11

2.5.1 CO₂检测含量的误差分析 11

2.5.2 注射泵进水体积误差分析 11

第三章 结果与讨论 12

3.1 操作压力对脱碳效率的影响 12

3.2 进气流速对脱碳效率的影响 14

3.3 操作温度对脱碳效率的影响 15

3.4 出气流速对脱碳效率的影响 17

3.5 再生水对脱碳效率的考察 19

第四章 结论 21

参考文献 22

致谢 24

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