船舶尾气净化工艺与设备研究

发布时间：2018-01-11 11:02

  本文关键词：船舶尾气净化工艺与设备研究　出处：《北京化工大学》2015年硕士论文　论文类型：学位论文

  更多相关文章： 船舶尾气 海水脱硫 脱硫塔 脱硫效率 优化设计

【摘要】：船舶柴油机排放尾气中的硫氧化物SOx已成为当前大气污染的重要来源。国际公约MARPOL73/78则对SOx的排放提出了严格要求。为了有效应对各国日益严格的船舶燃油硫含量和SO：的排放量限制,必须加强船舶硫化物排放控制研究。本文对比了多种技术,认为海水法脱硫剂(海水)就地取材,在船舶尾气排放控制上具有优越性。本文在分析SO2脱硫机理的基础上,设计了一套以海水或淡水加碱为脱硫剂的双模式烟气脱硫系统,可适应不同地区排放要求；采用先曝气再调节pH的工艺可减少设备数量及占地面积,投资成本小；采用文丘里管作为脱硫塔初洗器,降温冷却、初步洗涤SO2和除尘效果好,工艺流程简单,系统可靠性高。以脱硫塔作为整套海水脱硫装置的核心设备,采用文丘里管式预处理装置对入口烟气做初步处理,螺旋形喷嘴为雾化喷嘴,通过喷淋塔内气液两相流动的CFD模拟,发现安装两层布气板有利于均匀流场分布,降低流场整体速度；气相在喷雾曳力作用下流向发生变化,喷嘴附近形成湍流与漩涡,由此证明合理布置孔板布气板和增加喷嘴数量可提高装置脱硫效率。以柴油机燃烧尾气模拟船舶尾气,对加装文丘里管式预处理装置的海水脱硫系统的脱硫效果及影响因素进行实验研究与分析,发现：双层孔板布气板的合理布置可起到优化流场分布的作用,脱硫效率约提高40%,在总流量为4 L·min-1时,文丘里初洗区可清除约52%的SO2,起到降温除尘、初步洗涤和缩短主塔高度作用；海水碱度、pH、温度对脱硫效率影响较大,盐度影响较小。海水碱度增大,pH值增大,脱硫效率明显提高；烟气中8O2含量与脱硫效率呈负相关关系。当入塔8O2浓度增大到3040 mg·m-3时,需要液气比达到15 L·m-3才能取得脱硫效率97.04%以上,即达到燃油含硫限值小于0.1%；随着液气比的增加,脱硫效率会增大,当液气比增加到7.5 L·m-3以上后,脱硫效率增长变得缓慢。适当增大液气比是提高脱硫效率的有效途径,实验中液气比在7.5 L·m-3以上能保证较好的脱硫效率。
[Abstract]:The sulfur oxide SOx in the exhaust gas of marine diesel engine has become an important source of air pollution at present, while the international convention MARPOL73/78 has put forward strict requirements for the emission of SOx. The increasingly stringent sulphur content of ship fuel and SOs:. Emission limits. It is necessary to strengthen the research on the discharge control of marine sulphide. This paper compares various technologies and thinks that the desulfurizer (seawater) is made locally. Based on the analysis of the mechanism of SO2 desulfurization, a two-mode flue gas desulfurization system using seawater or fresh water alkali as desulfurizer is designed. Can adapt to the emission requirements of different regions; The process of first aeration and then adjusting pH can reduce the number of equipments and occupy an area, and the investment cost is small. The Venturi tube is used as the primary scrubber for desulfurization tower, cooling and cooling, the primary washing SO2 and dust removal effect are good, the process flow is simple, the system reliability is high, and the desulfurization tower is taken as the core equipment of the whole seawater desulphurization unit. The inlet flue gas was treated with Venturi tube pretreating device. The spiral nozzle was used as atomizing nozzle, and the CFD simulation of gas-liquid two-phase flow in the spray tower was carried out. It is found that the installation of two-layer air distribution plate is beneficial to the uniform flow field distribution and the reduction of the overall velocity of the flow field. The flow direction of the gas phase changes under the action of spray drag, and turbulence and whirlpool are formed near the nozzle. It is proved that the efficiency of desulphurization can be improved by reasonably arranging the orifice plate and increasing the number of nozzles, and the tail gas of the ship is simulated by the combustion tail gas of the diesel engine. Experimental study and analysis of desulfurization effect and influencing factors of seawater desulfurization system with Venturi pipe pre-treatment system are carried out. It is found that the reasonable arrangement of double orifice plate can play an important role in optimizing the flow field distribution. When the total flow rate is 4 L 路min-1, the initial washing area of Venturi can remove about 52% of so _ 2, play the role of cooling and dust removal, preliminary washing and shortening the height of the main tower. The pH of seawater alkalinity and temperature have a great effect on desulfurization efficiency, but little effect on salinity. The content of 8O _ 2 in flue gas was negatively correlated with desulfurization efficiency, when the concentration of 8O _ 2 increased to 3040 mg 路m ~ (-3). The desulfurization efficiency is above 97.04% when the liquid-gas ratio is 15L 路m ~ (-3), that is, the limit value of sulfur content of fuel is less than 0.1L 路m ~ (-3). With the increase of liquid-gas ratio, the desulphurization efficiency will increase. When the liquid-gas ratio increases to more than 7.5 L 路m-3, the desulfurization efficiency increases slowly, and the proper increase of liquid-gas ratio is an effective way to improve the desulfurization efficiency. In the experiment, the ratio of liquid to gas above 7.5 L 路m ~ (-3) can guarantee a better desulphurization efficiency.
【学位授予单位】：北京化工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X736.3
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本文编号：1409245