陶瓷行业白烟废气治理的初步研究.pdf

陶瓷行业白烟废气治理的初步研究 ＊ 彭闪江 苏伍根 佛山市环境监测中心站, 广东 528000 摘要 简述了陶瓷废气处理的技术方案、工艺流程及其废气净化装置的结构组成。 以某陶瓷厂白烟废气治理为实例, 废气净化装置对废气中白烟的去除效果明显, SO2和烟尘浓度从处理前的568. 8 mg Nm3和324. 6 mg Nm3降低到 76. 2. 0 mg Nm3和122. 4 mg Nm3, 去除率分别达到 86. 6和 54. 6, 处理后的 SO2和烟尘排放浓度都达到工业窑炉大 气污染物排放标准 GB 9078-1996 的二级标准。试验结果表明, 该废气净化装置及技术解决了陶瓷行业废气的白烟 污染, 并具有较好的脱硫除尘效果。 关键词 废气 治理 陶瓷行业 ＊佛山市环境保护局专项基金资助项目 0 前言 陶瓷企业干燥生产线上的喷雾干燥塔产生的废 气中含有大量水蒸汽 ,排入大气后遇冷即凝结成无数 小雾滴,从而形成白色烟雾 简称白烟 , 烟雾中还含 有大量未完全去除的粉尘和从锅炉中夹带的 SO2等 污染物,对周围环境造成一定的影响。由监测数据显 示,排放的 SO2浓度 , 烟尘浓度都超过了排放标准的 允许值 ,因此 , 需要配套建设废气的治理工程。目前 常用的废气处理方法中 , 脱硫除尘技术已日趋成 熟 [ 1- 3] ,但多集中在烟气脱硫或者是除尘等单一方面 上,对陶瓷废气中的白烟治理, 很少引起研究者们的 注意 。而常用的湿法烟气脱硫除尘设备中,虽然常配 置有脱水装置如除雾板、挡水板等 ,但脱水效率不高, 气、 水分离效果差,未能解决“白烟废气”的污染难题。 为有效治理陶瓷企业生产线喷雾干燥塔所产生 的废气中的白烟 、 SO2和烟尘污染 , 对常用的废气净 化装置及相关技术进行了改进 ,并以某陶瓷厂的废气 治理进行了试验研究 ,旨在为探讨和改进陶瓷行业废 气消烟、 脱硫、 除尘的污染治理技术 ,并为相关行业的 废气治理提供参考。 1 技术方案与工艺流程 1. 1 技术方案 陶瓷厂生产线上的喷雾干燥塔排出的烟气,经风 机抽入废气净化器后经过 3 层旋流板的离心作用 ,使 吸收液 水 和烟气中的污染物充分混合 , 沉降吸收 达到除尘脱硫的目的 , 净化后的含水烟气通过脱水 器,经防水槽而达到气液分离 达到去除大部分水汽 的目的 ,并进入干燥塔烟囱与来自隧道窑窑头烟囱 排出的热气混合 ,使烟气得到升温, 使其残余的水汽 不致冷凝, 最终达到消除“白烟”的目的。 1. 2 工艺流程与废气净化装置结构 喷雾干燥塔将泥浆干燥成泥粉时, 产出温度约 90 ℃ 含水汽烟气 。如图 1、图 2所示,烟气经管道 ,由 锅炉引风机 A 引送经进气管 7 至旋流板塔 B 底层 螺旋上升, 与进水管 4 、盘式喷洒器 5 输送下来的 水逆流相遇 。盘式喷洒器上密布小孔,使水与烟气接 触更加充分 。旋流板 6 为内向板, 水被穿过旋流板 的烟气喷成雾状 ,与烟气充分接触, 对烟气进行充分 洗涤, 并在离心力作用下甩向塔壁, 然后聚集成液环 后受重力下流, 经集水支管 10 、 集水管 9 流至下一 块旋流板, 逐板流至塔底 。烟气被冷却至40 ℃左右, 同时除尘脱硫。净化后的含水烟气经过旋流板塔上 部的脱水板 3 , 脱水板可以加快烟气的旋转速度 ,产 生离心力, 烟气中的水汽被强制甩向塔壁 ,顺壁流下, 从而达到气液分离的目的。烟气最后经塔顶的锥管 2 ,进一步降低了含水量。废水经塔底排水管 8 流 出旋流板塔 ,经沉淀中和处理后, 经离心泵流至储水 池冷却,供循环使用 。 烟气通过旋流板塔的排气管 1 后 ,在烟囱 C 中 与来自产品烧成隧道窑窑尾烟气,经保温管道输送与 约200 ℃ 的废热气相混合 。烟气又被加热到一定温 度而废热气温度下降, 混合气体再排入大气 ,其中的 残余水汽就不致冷凝 ,烟囱出口废气的“白烟”现象即 可消除 ,同时原直接排放的烧成废气温度降低, 减少 高温污染 。在旋流板塔内, 对烟气还有脱硫除尘 作用 。 45 环 境 工 程 2006年 10 月第 24卷第 5 期 图 1 烟气除尘除湿脱硫工艺流程 1排气管; 2锥管; 3脱水板; 4进水管; 5盘式喷洒器; 6旋流板; 7进气管; 8排水管; 9集水管; 10集水支管; 11锅炉风机; 12旋流板塔。 图 2 废气净化装置剖面图 2 结果与讨论 2. 1 监测结果 试验在除尘脱硫的基础上消除了喷雾干燥塔排 出的白烟 ,相关指标经有关部门检测达到工业窑炉 大气污染物 排放标准 GB 9078-1996 排放 标准 表 1 。 表 1 不同处理条件下废气排放浓度及去除率 项目 风量 m3h- 1 烟气流速 ms- 1 烟气 湿度 烟气 温度 ℃ 标准 体积 L SO2浓度 mg Nm- 3 烟尘浓度 mgNm- 3 处理前 平均值 24 349. 617. 92. 575201. 7568. 8324. 6 关热风管 时平均值 16 88611. 52. 856. 4315. 576. 2122. 4 关热风管 时去除率 86. 662. 3 开热风管 时平均值 3 018. 62. 43. 4115. 4171. 6258104. 7 开热风管 时去除率 54. 667. 7 2. 2 分析与讨论 通过将烟气通入冷却塔中 , 用冷却水洗涤烟气, 使其降温, 洗去烟气中的尘粒和部分二氧化硫 ,同时 除去其中大部分水汽 ,然后将净化后的烟气与产品烧 成隧道窑排放的热废气混合排放 , 起到了消除水汽、 SO2和粉尘的作用同时使原来直接的烧成废气温度 降低 ,减少高温污染。从监测结果来看 , 烟气经废气 净化器处理后并与来自产品隧道窑窑头约200 ℃的 废热气混合后 ,基本上不见白色水汽烟雾, 同时, SO2 和烟尘浓度从处理前的568. 8 mg Nm 3和324. 6 mg Nm3 降低到258. 0 mg Nm 3 和104. 7 mg Nm 3 , 去除率分别达 到54. 60 和 67. 70。从浓度指标看 ,处理后的 SO2 和烟尘排放浓度都达到工业窑炉大气污染物排放标 准 GB 9078- 1996 的二级标准 。 由于最终出口气体有部分来自产品烧成隧道窑 窑头的废热气, 其本身含有 SO2等污染物 ,因此造成 最终出口烟气的污染物去除率较低 ,从表 1 的检测结 果看, 如果关闭热风管 ,SO2和烟尘浓度的去除率分 别达到86. 6 和 54. 6。同骆建晖等人的研究结果 相比较,脱硫的效果比较好,但除尘效率稍低 [ 4-6] 。 本废气净化处理技术采用可热废气与烟气混合 的加热方式 ,循环使用冷却水, 而且充分利用了陶瓷 工业中原有的设备, 因此运行费用低 ,节能减耗。 参考文献 [ 1] Gengiz P A , Abbasian J, Khalili N R, Slimane R B, and Ho K K. 2002 . Development of Durable and Reactive Regenerable Sorbents for High Temperature Flue Gas Desulphurisation. International Journal of Environmental and Pollution 17 1 2 82 -101. [ 2] Chen Z Y and Yeh J T. 1998. A sorbent regenerator simulation model in copper oxide flue gas cleanup process. Environmental progress 17 2 61-69. [ 3] 吴泽安. 旋流板塔及其在废气处理中的应用. 环境工程, 1997, 12. [ 4] 骆建晖, 许闽明, 李康文. 旋流板塔双碱法在熔化炉废气脱硫除 尘中的应用. 环境工程,2003, 8 . [ 5] 谭亚军等. 旋流板塔在碱性黑液烟气脱硫中的应用. 环境工程, 1998, 1. [ 6] Lin Y S , Deng S G . 1998 . Removal of Trace Sulfur Dioxide from Gas Stream by Regenertive Sorption Process. Separation and Purification Technology 13 65 -77. 作者通讯处 彭闪江 528000 广东佛山市禅城区汾江南路 127 号 佛山市环境监测中心站 2006- 01-17 收稿 46 环 境 工 程 2006年 10 月第 24卷第 5 期 THE PRIMARY STUDY ON CLEANING EQUIPMENTS FOR TREATING FLUE GASIN CERAMICS INDUSTRYPeng Shanjiang Su Wugen 45 Abstract Technology scheme and flow associated with the composition of cleaning equipments for treating flue gas from ceramics industry were compendiously presented. Cleaning equipments and technology possessed a highest removal in treating test of a ceramics plant, and the average concentration of SO2could be reduced from 568. 8 mg Nm3to 76. 2 mg Nm3, and that of soot simultaneously from 324. 6 mg Nm3to 122. 4mg Nm3. The average removal rate of SO2andsoot reached 86. 6and54. 6respectively, which are up to the second -order of“ Emission Standard of Air Pollutants for Industrial Kiln and Furnace” GB 9078 -1996. The results indicated that cleaning equipments and their technology resolved the write flue gas pollution and simultaneously achieved a preferable desulphurization and dust collecting effects in treating flue gas of ceramics industry. Keywords flue gas, treatment and ceramics industry THE DESIGN OF DUST CATCHER SYSTEM FOR PRODUCTION WORKSHOP OF CARBON FACTORYLiu Zhangxian LuoLingxian Yang Jiawen 47 Abstract Through project instance of dust catcher for the production workshop of a carbon factory, it was expatiated the design scheme of pollulants control of the integrating system of fast melt of pitch, separating dust hoods centralized bag collectors as well as multi-tube stativ precipitatorsfor roasters, which would be used for the processes of melting, crushing , mixing and roasting a pitch. The results showed that the project could let all the pollutantsfrom the workshop meet the emission standards. This project explored a feasible route of dustproof and dedusting in the small sized carbon factory. Keywords carbon factory , dust, asphalt, control dust system and purification efficiency STUDY ONLEVIGATING BOTTOM ASH TO OPTIMIZE ITS QUALITY Yu Jinglong Zhai Jianping Li Qin et al 50 Abstract The bottom ash drained off from Changxing power plant was presumed upon levigating to national class Ⅱ fly ash. The results show that SiO2and Al2O3are the main chemical compositions and the main mineral phase is vitreous body . The trace elements and radioelements are under the limit of national standard. The properties of bottom ash are the best as the residual on sieve 45 μ m remainder is almost 10. The pozzolanic activities of bottom ash are better than those of the levigated class Ⅱ fly ash. Keywords bottom ash, levigating process and utilization STUDY ON USING SALT GYPSUM FROM SEA SALT INDUSTRY TO PRODUCE LIGHT WALL MATERIALMa Mingjie Zhu Li 53 Abstract It has been researched that the salt gypsum as a waste residue from sea salt industry can be used as a raw material to produce a kind of hollow batten as light wall materials by some processes. This product cost can be reduced greatly by applying modified processes and raw materials as compared to natural gypsum batten. The kind of hollow battenwhose perance indicatorsmeet the national standards can replace the product made of natural gypsum. Keywords waste residue, salt gypsum,wall materials and eco-environment REUSE OF MSWI FLY ASH IN MAKING OF GLAZED TILE Zhang Haiying Zhao Youcai Qi Jingyu 56 Abstract MSWI fly ash was used to make glazed tile based on analysis of its characterization, together with red argil and cylinder sand. Besides, influence of fly ash on perance and microstructure of glazed tile as well as its environmental risk were studied. It is found that major chemical constitution of fly ash is CaO, SiO2and Al2O3, featuring an SiO2-Al2O3-metal oxides system, which can be used as the raw material of glazed tile. When 20fly ash is used, glazed tile presents nice perances compression strength being 19. 2 MPa, water -absorption rate being 7. 2, presentation quality standing in the grade one category . In addition, leaching, in accordance with the HVEP standard, from glazed tile, of As, Pb, Ni, Cr, Cu, Hg and Cd can t be detected, and that of Zn is reduced to 1. 4, in comparison with fly ash. While, leaching, in accordance with the ALT standard, from glazed tile, of As, Pb, Ni, Cr, Cu and Zn is reduced respectively to 5. 6, 0 . 1, 6. 7, 5. 8, 5. 6 and 2 . 9, compared with fly ash, and that of Hg and Cd can t be detected. Keywords MSWI fly ash, glazed tile, environmental risk analysis, perance andmicrostructure APPLICATION OF WET CRUSHING IN REUTILIZATION OF DISCARDED PRINTED CIRCUIT BOARDSZhang Hongjian Zhao Yuemin Wang Quanqiang et al 60 Abstract Based on components and crushing characteristics of non -metal composition of the discarded printed circuit boards PCBs, secondary pollution problem produced by dry crushing is validated and studied with thermogravimetry -infrared deterctor and wet crushing is providedto solve this problem. From the comparison between experimental results of dry crushing and wet crushing , it can be observed that cumulative yield of each particle size fraction of wet crushing has a change, but the distribution characteristics of particle is not changed, and the productivity of coarse particleswith the size larger than -52 mm and superfine materials with the size less than 0. 045 mm are obviously increased. Finally, the reasons of the difference are analyzed. 4 ENVIRONMENTAL ENGINEERING Vol. 24, No. 5,Oct. , 2006