再生气氛对活性焦吸附—热再生活性影响的研究

发布时间：2018-01-06 11:17

本文关键词：再生气氛对活性焦吸附—热再生活性影响的研究　出处：《贵州大学》2015年硕士论文　论文类型：学位论文

【摘要】：炭法烟气脱硫脱硝技术是一种不耗水、无二次污染、可同时脱除多种污染物和回收硫资源的技术,目前已应用于多种工业烟气的治理。然而,运行过程中其存在运行成本高和能耗高两个问题,限制了它的广泛应用。其中,运行成本高主要是因为吸附—再生过程中存在大量的碳损失,能耗高是因为需要较高的再生温度。本文从寻找价格低廉的碳基吸附剂、提高吸附剂的脱硫脱硝性能、减少碳损失和降低热再生温度四个方面开展实验研究,对比研究了价格低廉的兰炭在烟气脱硫脱硝领域的应用前景,研究了吸附气氛和吸附剂性质对脱硫脱硝效率的影响,同时在不同的再生气氛下分析升温速率、再生温度、气体浓度和再生时间对吸附剂的热再生活性和碳消耗的影响。本文选用已商业化应用了的活性焦(AC-1)、活性炭(AC-2、AC-3),和煤的干馏副产物——兰炭(AC-4)作为碳基吸附剂,在含水含氨气气氛、无水含氨气气氛和含水无氨气气氛下进行脱硫脱硝实验,讨论吸附气氛和吸附剂性质对脱硫脱硝效率的影响。结果表明,在含水无氨气气氛下以AC-2、AC-3和AC-4的脱硝性能最佳,而在含水含氨气气氛下以AC-1和AC-4的脱硝性能最佳,主要是因为AC-2和AC-3具有较大的比表面积,在含水含氨气气氛下能够有效提高吸附剂的脱硫效率,可在吸附剂的表面生成大量的硫铵盐,从而导致吸附剂的微孔堵塞,抑制了脱硝反应的进行。对在含水含氨气气氛下脱硫脱硝后的四种碳基吸附剂进行加热再生,从再生吸附剂的脱硝效率、脱硫效率和SO2回收率三方面比较四种碳基吸附剂的热再生活性,并结合C/SO2(再生1 mol SO2所消耗C的量)对热再生过程中的碳消耗进行了分析。结果表明,经一次加热再生后,四种吸附剂的脱硫性能基本不变,AC-1的脱硝性能也基本不变,而AC-2、AC-3和AC-4的脱硝性能显著降低,主要是因为加热再生减少了吸附剂表面活性官能团的量,并对吸附剂的孔结构产生了影响;加热再生过程中,以AC-3的碳消耗最少,而以AC-2和AC-4的SO2回收率最高。另外,为减少化学碳消耗,可在较低温度下对吸附剂进行加热再生,此时SO2回收率仅稍有降低。分别在氮气气氛、含水气氛和含氨气气氛下对脱硫脱硝后的活性焦进行加热再生,讨论升温速率、再生温度、气体浓度和再生时间对活性焦热再生活性和碳消耗的影响。结果表明,在再生气氛中引入一定浓度的NH3,能够提高再生活性焦的脱硫脱硝性能,减少热再生过程中的碳消耗,但SO2回收率会显著降低;当引入水蒸气时,不能提高再生活性焦的脱硫脱硝性能,而使得热再生过程中的碳消耗增加;再生条件中,以再生温度对活性焦的脱硫脱硝效率和SO2回收率的影响最大,其次是升温速率和再生时间,随着再生温度的升高,再生活性焦的脱硫效率和SO2回收率逐渐提高,但碳消耗也随之增加。
[Abstract]:Carbon flue gas desulphurization and denitrification technology is a kind of technology which can remove many kinds of pollutants and recover sulfur resources simultaneously without water consumption and secondary pollution. It has been applied to the treatment of various industrial flue gas at present. The problems of high operating cost and high energy consumption in the process of operation limit its wide application. Among them, the high operating cost is mainly due to a large amount of carbon loss in the process of adsorption-regeneration. High energy consumption is due to the need for higher regeneration temperature. This paper from the search for low-cost carbon-based adsorbents to improve the desulfurization and denitrification performance of adsorbents reduce carbon loss and reduce the temperature of thermal regeneration four aspects of experimental research. The application prospect of low cost blue charcoal in flue gas desulfurization and denitrification was studied. The effects of adsorption atmosphere and adsorbent properties on desulfurization and denitrification efficiency were studied. At the same time, the heating rate was analyzed in different regeneration atmosphere. Effects of regeneration temperature, gas concentration and regeneration time on thermal regeneration activity and carbon consumption of adsorbents. The desulfurization and denitrification experiments were carried out in the atmosphere of water containing ammonia, anhydrous ammonia and water and ammonia without ammonia as carbon-based adsorbents, and the by-product of coal distillation (AC-4) was used as a carbon-based adsorbent. The desulfurization and denitrification experiments were carried out in the atmosphere of water containing ammonia, water containing ammonia and water and no ammonia. The effects of adsorption atmosphere and adsorbent properties on desulphurization and denitrification efficiency were discussed. The results showed that AC-2AC-3 and AC-4 had the best denitrification performance in the presence of water and ammonia. AC-1 and AC-4 have the best denitrification performance in the atmosphere of water and ammonia, mainly because AC-2 and AC-3 have larger specific surface area. The desulfurization efficiency of the adsorbent can be improved effectively in the atmosphere of water and ammonia, and a large amount of ammonium sulfate can be produced on the surface of the adsorbent, resulting in the micropore blockage of the adsorbent. Four carbon-based adsorbents after desulphurization and denitrification in aqueous ammonia atmosphere were heated and regenerated from the denitrification efficiency of regenerated adsorbents. The thermal regeneration activities of four carbon-based adsorbents were compared in terms of desulfurization efficiency and SO2 recovery. The carbon consumption during thermal regeneration was analyzed by using C / so _ 2 (the amount of C consumed by regenerated 1 mol SO2). The desulphurization performance of the four adsorbents was basically unchanged, and the denitrification performance of AC-2AC-3 and AC-4 was significantly decreased. The main reason is that heating regeneration reduces the amount of surface active functional groups of adsorbent and influences the pore structure of adsorbent. In the process of heating regeneration, the carbon consumption of AC-3 was the least, and the recovery of SO2 from AC-2 and AC-4 was the highest. In addition, to reduce the consumption of chemical carbon. The adsorbent can be heated and regenerated at lower temperature, and the recovery rate of SO2 is only slightly reduced. The activated coke after desulfurization and denitrification is heated and regenerated in nitrogen atmosphere, water atmosphere and ammonia atmosphere, respectively. The effects of heating rate, regeneration temperature, gas concentration and regeneration time on the thermal regeneration activity and carbon consumption of activated pyrolysis were discussed. The results showed that a certain concentration of NH3 was introduced into regeneration atmosphere. It can improve the desulfurization and denitrification performance of regenerated active coke and reduce the carbon consumption in the process of thermal regeneration, but the SO2 recovery rate will be significantly reduced. When water vapor was introduced, the desulfurization and denitrification performance of regenerated active coke could not be improved, but the carbon consumption in the process of thermal regeneration was increased. In regeneration conditions, regeneration temperature has the greatest influence on desulfurization and denitrification efficiency and SO2 recovery rate of activated coke, followed by heating rate and regeneration time, with the increase of regeneration temperature. The desulfurization efficiency and SO2 recovery of regenerated activated coke increased gradually, but the carbon consumption also increased.
【学位授予单位】：贵州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X701;TQ424.1

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