电石渣烟气脱硫工艺的改造和应用

发布时间：2018-02-21 01:11

  本文关键词： 电石渣 石灰石 脱硫技术 脱硫剂 脱硫岛　出处：《北京化工大学》2015年硕士论文　论文类型：学位论文

【摘要】：本着“因地制宜、以废治废、变废为宝、发展循环经济”原则,利用电石渣替代石灰石作为脱硫剂,达到了废物综合利用。目前,我国烟气脱硫工艺主要采用石灰石-石膏湿法脱硫,该工艺相对简单、运行稳定可靠,但是脱硫剂石灰石价格比较高,运行成本约占脱硫装置的30-35%,为了提高电厂运行经济效益,降低运行成本,采用电石渣法替代石灰石法相当必要的,用电石渣替石灰石进行脱硫,一方面大大减少了电石废渣的排放,降低了对环境的污染,取得了很好的环境效益;另一方面采用了价格低廉的脱硫剂,降低了运行成本,同时减少了石灰石矿的开采,降低了有限资源的消耗,对石灰石矿产资源进行了有效保护,同时也降低石灰石-石膏法中C02的排放量,获得经济效益的同时还获得了良好的环境效益及社会效益。通过对现有烟气脱硫技术的现状比较,充分利用当地的特点,将企业的电石渣循环利用,选用电石渣-石膏湿法进行烟气脱硫,具有以废治废,变废为宝的优点,减少了污染物的排放,同时也降低了生产运行费用。采用电石渣-石膏湿法脱硫的工艺路线后,根据烟气中二氧化硫的含量,设计了脱硫塔,并制定了严格的操作规程,如液气比、烟气流速等。同时将生成的亚硫酸钙通入空气强制氧化成硫酸钙,并从脱硫塔底部用浆液泵抽出,经过二级脱水后,得到含水量为10%的脱硫石膏。改造工程分为两个阶段实施,第一阶段将原有1#、2#两台吸收塔第一层喷淋下方新增一层托盘,第一、二层喷淋管及喷嘴进行改造,并在吸收塔内增加吸收塔内酸液收集装置,将酸液收集到氧化塔；第二阶段改造新建一台3#吸收塔,3#吸收塔采取三层喷淋(最上层密集喷淋)加一层托盘形式,3#吸收塔投运后将烟气轮流切换到3#吸收塔后再分别对两台老吸收塔进行改造,将老吸收塔的第三层喷淋改造成一层密集型喷淋层。通过改造后第一阶段在FGD入口SO2浓度≤2000 mg·Nm-3(使用原煤全硫含量≤0.8%)的前提下,脱硫出口SO2浓度降低到≤50 mg·Nm-3。第二阶段新、老吸收塔在FGD入口SO2浓度≤3500 mg·Nm-3(原煤的全硫含量≤1.5%)的前提下,脱硫出口SO2浓度降低到50 mg·Nm-3,脱硫效率达到98.6%,满足了环保指标要求。最后,针对本次脱硫改造工程的运行情况进行了叙述,通过计算生产运行成本和二氧化硫减排量,得到与石灰石法相比每年节约成本约880万元,二氧化硫排量降低了841.5吨／年,因此电石渣作为脱硫剂具有良好的经济效益和环保效益。
[Abstract]:In line with the principle of "treating waste according to local conditions, changing waste into treasure and developing recycling economy", calcium carbide slag is used instead of limestone as desulfurizer to achieve comprehensive utilization of waste. Wet limestone gypsum desulfurization is mainly used in flue gas desulfurization process in China. The process is relatively simple and stable and reliable, but the price of desulfurizer limestone is relatively high, and the operating cost is about 30-355.In order to improve the economic benefit of power plant operation, the desulfurization process is mainly made up of limestone and gypsum. It is necessary to use calcium carbide slag instead of limestone method to reduce operation cost. On the one hand, calcium carbide slag for limestone desulphurization, on the one hand, greatly reduces the discharge of calcium carbide waste slag, reduces the pollution to the environment, and obtains very good environmental benefits. On the other hand, the low cost desulphurizer is used to reduce the running cost, to reduce the mining of limestone, to reduce the consumption of limited resources, and to effectively protect the mineral resources of limestone. At the same time, the discharge of CO2 in limestone gypsum process is reduced, and the economic benefits are obtained, and good environmental and social benefits are also obtained. By comparing the present situation of existing flue gas desulfurization technology, we can make full use of the local characteristics. In order to recycle the calcium carbide slag and choose the wet method of calcium carbide slag and gypsum for flue gas desulphurization, it has the advantage of treating waste with waste and turning waste into treasure, thus reducing the emission of pollutants. At the same time, the production cost is also reduced. After adopting the technology route of wet desulfurization with calcium carbide slag and gypsum, according to the content of sulfur dioxide in flue gas, the desulfurization tower is designed, and strict operation rules, such as the ratio of liquid to gas, are worked out. At the same time, the generated calcium sulfite is forced to be oxidized into calcium sulfate through the air, and extracted from the bottom of the desulfurization tower by slurry pump. After secondary dehydration, the desulphurized gypsum with water content of 10% is obtained. The reconstruction project is divided into two stages. In the first stage, a layer tray is added under the first layer of the original 1 #2# absorption tower, the first and second layers of spray pipes and nozzles are modified, and the acid collection device in the absorption tower is added to the absorption tower to collect the acid solution to the oxidation tower; In the second stage of reconstruction, a new absorption tower was built, and the absorption tower was built in the form of three layers of spray (the highest layer of dense spray) and a layer of pallet. After the tower was put into operation, the flue gas was switched to the absorption tower in turn and then the two old absorption towers were renovated separately. The third layer spray of the old absorption tower was transformed into a dense spray layer. In the first stage, the SO2 concentration at the outlet of desulfurization was reduced to 鈮，

本文编号：1520568