循环流化床烟气脱硫装置对袋式除尘器影响的实验研究.pdf

烟 气 污 染 治 理 循环流化床烟气脱硫装置 对袋式除尘器影响的实验研究 赵旭东 清华大学热能工程系, 北京 100084 马春元 山东大学, 济南 250000 李振山 项光明 陈昌和 清华大学热能工程系, 北京 100084 摘要 在 1台与袋式除尘器配套的循环流化床烟气脱硫系统上, 通过对运行脱硫系统前后袋式除尘器的脱硫效果机 理性分析。 研究了循环流化床烟气脱硫装置对袋式除尘器工作稳定性、除尘效率和阻力的影响, 并提出了改进措施。 关键词 循环流化床烟气脱硫 袋式除尘器 干法 1 前言 循环流化床烟气脱硫装置具有工艺相对简单 ,脱 硫效率较高 ,设备安装占地面积小 , 脱硫剂 石灰 与 水的消耗量少, 脱硫产物比较容易处理等特点 ,因此 越来越受到人们的关注 。循环流化床烟气脱硫装置 需与电除尘器或袋式除尘器配套使用。 在此着重研究了装置投入运行后循环流化床烟 气脱硫装置,对配套使用的袋式除尘器产生什么样的 影响 。这些研究为循环流化床烟气脱硫技术的发展 和在燃煤电厂的大规模应用提供了依据 。 2 脱硫系统简介 循环流化床烟气脱硫装置 CFB-FGD 主要由脱 硫反应塔、喷浆装置、喷水调节装置 、分离回送装置、 模拟给料装置、在线监测自动控制系统以及袋式除尘 器等几大部分组成, 工艺流程简图如图 1 所示 。 由锅炉排出的热烟气经文丘里装置进行预除尘 处理后进入脱硫塔内 。脱硫浆液和循环固体颗粒物 经流化后由两相流喷嘴喷入塔内, 与烟气发生脱硫反 应。反应后烟气进入下排气分离装置, 分离下来的固 体颗粒物 ,通过回送装置送回至文丘里喉口。净化后 的烟气通过袋式除尘器除尘后 ,经引风机排入大气 。 脱硫装置安装在 1 台 1 t h 燃煤锅炉上, 设计处 理烟气量为3 500 m 3 h ,循环流化床与袋式除尘器配 套使用,脱硫反应塔总高 20 m 。塔的入口处设有1 套 飞灰给料装置, 给料装置由调速电机控制 ,可以实现 给料速度的连续调节 ,以模拟各种不同的入口飞灰浓 度; 在供浆管路基础上外加 1 套调温水路, 以保证在 钙硫比不变的情况下调节脱硫反应的温度、 湿度等参 数。在锅炉烟气出口处和袋式除尘器后 ,各安有 1 个 调节风门, 可以用来调节烟气量的大小 ; 对整个脱硫 装置进行保温处理。 图 1 CFB -FGD 脱硫系统示意图 1模拟给料装置; 2调温管路; 3喷浆装置; 4脱硫反应塔; 5 下排气分离器; 6回料装置; 7浆液泵; 8空气压缩机; 9制浆 装置; 10袋式除尘器; 11引风机 ①～ ⑤为测点 。 采用脉冲反吹式玻纤袋式除尘器,除尘器运行参 数处理风量3 000～ 4 000 m 3 h; 过滤风速 0. 5 m s; 除 尘效率99. 8 ; 阻力 1 500 Pa ,清灰方式为定时脉冲 反吹。滤袋采用普通素布 玻纤布不经过处理, 价格 便宜 ,最高工作温度为 150 ℃, 滤袋长 3 m , 直径为 205 mm ,实验中将清灰时间间隔定为 2 min。 3 实验条件 实验所用的脱硫剂是山东淄博产的 Ca OH 2 粉,经化验测定其纯度为 88. 72, 另外含有少量的 39 环 境 工 程 2005年 10 月第 23卷第 5 期 CaCO3和CaO。Ca OH 2粉在浆液灌内制成不同浓度 的浆液,充分搅拌后, 喷入脱硫塔内。锅炉用煤分别 含硫量约为2. 5～ 3. 7。试验所用粉煤灰的密度、 主要化学成分化验结果和粒径分别见表 1 和表 2。 为便于分析 ,本试验的典型工况指 进料 Ca S 1. 2, 近绝热饱和温度 Δt 13 ℃, 脱硫塔内浓度 C 500 g m 3 ,烟气速度 v 5. 0 m s, 浆液浓度 C10。 表 1 实验用粉煤灰主要成分及密度 成分SiO2Al2O3Fe2O3CaONa2OK2OMgO 堆积密度 kgm- 3 百分含量 51. 231. 57. 23. 30. 140. 720. 89775 表 2 实验用粉煤灰粒径分析 粒径尺寸 μ m 质量百分比 粒径尺寸 μ m 质量百分比 74. 04 . 58 4 袋式除尘器的脱硫机理及实验研究 袋式除尘器的脱硫作用, 国内外许多专家学者都 作过研究 ,很多文献进行了报道 [ 1] 。 研究认为袋式除尘器脱硫效果明显 。一般认为 袋式除尘器对系统脱硫效率的贡献率为 20 左右。 Blythe [ 2] 等人中试实验表明 袋式除尘器有显著的脱 硫效果 ;Mark [ 3] 等人在 Coolside 工艺的研究过程中 ,也 发现袋式除尘器脱硫效果显著 ; 浙江大学王乃华、骆 仲泱等半干法循环流化床烟气脱硫试验表明 ,当近绝 热饱和温度为 10 ℃, 钙硫比为 1. 5, 循环倍率为 10 时,脱硫反应塔脱硫效率为 75, 脱硫系统的脱硫效 率为 92,袋式除尘器脱硫效率贡献率为 17。由 于袋式除尘器脱硫作用明显, Babcock and the effluent should meet the first-order of “ Integrated Wastewater Discharge Standard” GB8978 -1996 . Keywords oil-separting tank, airfloat system, biocontact oxidation and refinery wastewater DESIGN FOR PENG′ AN DOMESTIC SEWAGE TREATMENT PROJECTYang Kaiming et al 27 Abstract Oxidation channel technique is one of the essential techniquesfor domestic sewage treating currently. It was used to treat domestic sewage of Peng ′ an, Sichuan Province. As a result, the treated sewage can meet the first-order of “ Integrated Wastewater Discharge Standard” GB8978-1996 . It was presented that the sewage quality and the treating standards of the sewage treatment works, selection of the technique procedure, cardinal treating structures and equipments, design characteristics and treating results, main technical -economic inds etc. , which may be a reference for sewage disposal engineering design. Keywords sewage treatment plant, design, technique, structure and equipment ENQINEERINGTREATMENTOFWASTERWATERFROMABSTRACTOFCHINESE TRADITIONAL MEDICINEFeng Zhaohua 29 Abstract Through an actual example ofwastewater treatment project, it has been introdulced that an effective treatment technology, which mainly involves the sequential combination of the three processes of air -floatation, UBF and CASS, for treating the high -concentration wastewater from extraction of Chinese traditional medicine. Demonstrated by the engineering operation and effect, this treatment technology can steadily ensure that the effluent quality meets the first-order of “Integrated Standard of Wastewater Discharge” GB8978-1996completely , and the removal rates of all pollutants can be up to 90～ 99. Keywords treatment project, high -concentrationwastewater, Chinese traditional medicine and extraction ENGINEERING PRACTICE OF TREATMENT OF PACKAGING AND PRINTING WASTEWATER ChengKaiying et al 32 Abstract The process of “pretreatmentA2O” was selected to treat packaging and printing wastewater in light of the characteristics of wastewater quality. The practice results show that the process is reasonable and advanced. The water quality of effluent can come up to the 1st level standard of“ Discharge Limits of Water Pollutants” DB44 26 -2001. Keywords packaging and printing wastewater, pretreatment, hydrolytic acidification and biocontact oxidation HIGH CONCENTRATION FLAX RETTING WASTEWATER TREATMENT AND REGENERATION REUSELiu Zhixiao et al 34 Abstract Flax retting wastewater producedwhenflax was rettedwasa sort of high concentration organic wastewater. The effluent quality was better than that of the designing when combined air flotation-oxidation ditch-stabilization pond processwas adopted. The renovated water generated by the advanced treatment process could be reused in flax retting process, with which water resource could be recycled well in production process of the company. Keywords flax retting wastewater, air flotation, oxidation ditch, stabilization pond and renovated water TECHNOLOGYOFTREATINGPRINTINGANDDYEINGWASTEWATERBYHIGH - PERANCE COMPACT REACTOR HCRSun Cuiling et al 37 Abstract Applicaiton of HCR to the treatment of the printing and dyeing wastewater is introduced. The quantity of influent is11 000 m3 d, CODCris about 2 500 mg L, pH is about12, chroma is600～ 800multiples. After reconstruction, the resultsof running shows that the capability of treatment was highly improved, effluent CODCris 360 mg L and chroma is 400 multiples. The efficiency of removal of CODCris 86 and that of chroma is 50. The project is of less investment and stable running. Keywords technology of HCR, wastewater treatment and printing dyeing wastewater THE EFFECTS OF CFB-FGD ON THE BAG FILTERSZhaoXudong et al 39 Abstract A double circulating fluidized bed flue gas desulphurization CFB -FGDsystem is installed to control SO2emissions, followed by bag filters to remove dust from the flue gas. In order to study the effects of desulphurization on the bag -filters, testings on the operational stability, de -dust efficiency and resistance of the filterswere carried out both before and after running of the CFB-FGD system. Based on the testing results, the desulphurization mechanism was derived and demonstrated. Some modifications to enhance the perance of the clean-up system were also given. Keywords CFB -FGD, bag filters and dry desulphurization 3 ENVIRONMENTAL ENGINEERING Vol. 23, No. 5,Oct. , 2005