【作者】 蒋文举；

【导师】 钟本和；

【作者基本信息】 四川大学 ， 化学工艺， 2003， 博士

【摘要】 活性炭烟气脱硫是一种高效资源化的烟气脱硫工艺，它不但可以消除烟气SO₂的污染，而且还可以回收硫资源，是当前研究开发的重要脱硫方法。活性炭吸附催化氧化SO₂的性能及再生技术是该工艺的关键，一直是国内外科技人员研究的重要课题。本文主要对微波新技术在脱硫活性炭改性和再生中的应用进行了深入研究，以期找到一种经济有效的脱硫活性炭的改性方法和再生技术。 在微波场中考察了微波功率、活性炭量、载气流量等对活性炭升温行为的影响。微波场中活性炭的升温行为可分为快速升温（大约60s左右）和升温缓慢两阶段，大约120s后到达高温平台。该温度主要取决于微波功率，活性炭量只对升达最高温度有影响，对升温速率基本没有影响，载气流速对活性炭的升温影响较小。活性炭在微波场中的升温行为可以用对数式和二次多项式来描述。 通过微波在不同微波功率、作用时间对不同粒径活性炭进行改性，对改性前后活性炭孔隙结构、表面基团、元素组成、微晶结构的变化进行了测试，表明微波处理使活性炭比表面积变化不大，孔容稍有缩小，主要变化发生在中孔范围，孔径分布变化不大，只是向小孔方向发生稍微的移动，活性炭基本微晶增大，石墨化程度提高。微波加热使活性炭表面含氧官能团以CO_x形式分解，微波强度越大，氧含量越少，炭中以吡咯氮形式存在的氮元素含量增加。 通过比较微波改性活性炭前后的吸附脱硫能力，结合它们的表面物理和化学性质的变化分析，确认微波改性活性炭的脱硫性能有显著提高，其作用机理在于微波处理后，活性炭表面微观形貌发生了较大的变化，化学基团发生分解，碱性特征增强，表面含氧量减少，以CO形式释出的含氧官能团分解后产生的活性部位和毗咯氮官能团数量增加，吸附502的表观活化能降低。通过微波和电加热改性活性炭的对比研究发现:在微波改性活性炭的过程中，除了微波热效应之外，还存在有微波的非热效应，使活化过程速率增强、降低反应活化能等，从而使微波改性活性炭具有更高的脱硫能力。 应用正交实验研究了微波功率、辐照时间、活性炭粒径对微波改性活性炭脱硫效果的影响，显示微波功率是决定改性活性炭502吸附容量的关键因素，微波功率的增加可以加强改性活性炭的502吸附能力，辐照时间对活性炭改性的影响在4一smin内突出，活性炭粒径越小，改性效果越好，对50:吸附容量也越大。 对502动态吸附实验表明，微波改性活性炭使脱硫效率提高，502吸附容量增大，穿透时间延长。进口502浓度越高，气速越低，穿透时间越长，502吸附容量越大。脱硫最佳操作温度为60℃一80℃。烟气中02和水蒸气对改性活性炭吸附502的产生重要影响，应根据实际情况调节其含量。 建立了微波改性活性炭固定床吸附过程的一维数学模型，测定了NZ一姚一50，体系中502在微波改性活性炭上等温吸附的总传质系数，由K。和q/qco的关系曲线可知，吸附过程属于多步骤联合控制。利用模型模拟了微波改性活性炭床层上502穿透曲线，模拟计算和实验测定基本一致。表明提出的模型具有一定的准确性，可供装置设计或工艺计算时参考。 最后，采用微波技术对饱和含硫活性炭进行了再生实验，结果表明在较低的微波强度下可以获得高浓度的502气体和回收率，微波再生时间极短，在微波功率>150W，3005内即可解吸完全。活性炭量越大，载气流量越小，微波功率越大，越有利于 502出口浓度的提高。更多还原

【Abstract】 Flue gas desulfurization （FGD） by activated carbon is an efficient, widely applied recycling technology that can not only remove sulfur dioxide （SO2）, but also recover the sulfur resource. Therefore, the promising FGD technology has been under intensive research. The SO₂ adsorption and oxidation capability and the regeneration technique of activated carbon are key factors to the successful performance of this technology and hot research arenas in the world. This dissertation focused on the modification of activated carbon and its regeneration by using microwave technology in order to find a cost-effective and technically feasible FGD process.The effects of the microwave power, dosage of activated carbon, and flow rate on the behavior of activated carbon were investigated under microwave radiation. The rise of temperature can be divided into two phases: rapid change phase （0- 60 seconds） and slow change phase （60-120 seconds）. In about 120 seconds, the temperature approaches a stable value. The stable temperature of activated carbon is primarily determined by the power of microwave. The dosage of activated carbon only affects the stable temperature but shows little influence on the rate of the temperature rise. The flow rate of gas has little effect on the heating rate of the activated carbon. The behavior of activated carbon’s temperature rise can be described by the logarithm or the second order polynomial.Activated carbons in different sizes were processed under various powers ofmicrowave with different time. The pore structures, surface groups, elemental composition, and microstructures of both conventional and modified activated carbon were tested. It was found that modified activated carbon had little change in the surface, modest shrink on pore volume and substantial change in the mediate-size pore, a little change in pore size distribution, compared with the conventional activated carbon. The fundamental crystallites of modified activated carbon aggrandize and its graphitizing increases as well. Heating with microwave induces dissociation of surface groups over activated carbon to form COx. The less the oxygen content and the more content of N element in the form of pyrrole-N were observed under stronger microwave power radiation.It was affirmed that the desulfurization capability of activated carbon could be greatly increased by microwave modification. According to the analysis on surface physical and chemical characteristics, a mechanism was concluded: Modified by microwave, functional groups begin to dissociate, alkalescency is enhanced, and surface oxygen content is reduced; the amount of active sites produced by dissociation of oxygen-containing groups increased, so did the pyrrole-N groups. Apparently, the activated energy of SO₂ adsorption decreased. In the process of microwave processing, in addition to heat effect of microwave, non-heat effect of microwave also exists, which increases the rate of activation process and decreases activated energy of reactionThe effects of power of microwave, radiation time and activated carbon sizes on desulfurization were studied by a Crossover experiment. The power of microwave is a key factor for SO₂ adsorption capability. The increase of the power of microwave can enhance adsorption capability of activated carbon. The radiation time can play a significant role on modified activated carbon in 4-5 minutes. The higher adsorption capability of the modified activated carbon was obtained using smaller activated carbon.The results of the dynamic experiment of SO₂ adsorption show that microwave-modified activated carbon has a high desulfurization capability and a long breakthrough time. A higher influent concentration of SO₂ and a lower flow velocity will prolong the breakthrough time and increase the SO₂ adsorption capability. The operation temperature is suggested between 60 ℃and 80℃. Theoxygen and vapor concentration in flue gas greatly affects on the SO₂ adsorption capacity.A one-dimension mathematical更多还原