液哨超生在循环水杀菌的应用

第28卷第1期化学反应工程与工艺Vol 28, No 12012年02月Chemical Reaction Engineering and TechnologyFeb.2012100L761(20124液哨超声在循环水杀菌的应用张陈成,吕效平,韩萍芳(南京工业大学化学化工学院,超声化学工程研究所,江苏南京210009:研究了一种新型液哨式超声发生器,以循环水作为动力源,进行循环水的杀菌处理,同时探讨了簧片哨结构循环水水压以及温度对杀菌效果的影响,簧片响较好结构为簧片厚度(mmx簧片长度(mm)x喷距(mm)04×12×2,声强325Wm2,入口压力07MP,流量24mh,水温25℃,经过60min的处理,杀菌率最高84%·该系统有结构简单、坚固耐用、处理量大、耗能小等优点,具有工业化大规模的水处理的应用前景关调:超声杀中图分类号:TQ54文识码:A在工业循环水系统中,由于水的不断蒸发浓缩、物料泄露和适宜的水温,造成了细菌的大量繁殖,而生物黏泥在设备上的附着会严重影响设备运行效率,增加了设备能耗。目前国内通用的微生物控制方法主要是投加工业杀菌剂,这对人类和环境水生物都有不同程度的毒性,因此环境友好型的杀菌方法成为目前研究的热点超声杀菌是一种新型水处理技术,根据超声发生源的不同,目前主要有电功率超声和机械式超声田张帆等初步研究了电功率超声处理循环冷却水,通过实验验证了利用超声杀菌有较好的灭菌效果。本研究主要探讨机械式超声灭菌方法,由于机械式超声发生器结构简单、坚固耐用、处理量大、利用流程中的工业水泵提供超声能量、耗能小和设备成本低等优点队,适合工业上大规模运用作为超声杀菌的方法。1液哨结构液哨超声发生器,又称簧片哨。液哨主要由喷嘴、喷距调节管和簧片组成,剖面结构图见图1·该发生器是通过喷嘴的高压水流冲击簧片,使得簧片产生振动,产生超声波喷面图、唢嘴簧片喷距调节管簧片槽固定螂栓8mm水流m图1液哨剖面图Fig 1 Section View of Reed whist收痛日2011-1209修订日舞:201201-19作者筒介张陈成(1985),男,硫士研究生:吕效平(190),男,教授,博士生导师,通讯联系人. E-maiLxpla@cd第28卷第1期张陈成等液哨超声在循环水杀函的应用2液哨杀菌机理当超声波能量足够大时,就会产生“超声空化”现象,主要是液体中的微小气核在超声波的作用下被激活,表现在泡核的振荡、生长、收缩、崩溃等一系列动力学过程刀。液体中的微小气泡在超声的作用下振动、生长并不断聚集声场能量,当能量达到某个值时,空化气泡急剧崩溃闭合,这时会释放出巨大的能量,并产生高速强劲的微射流,使碰撞密度极高。空化气泡在急剧崩溃的瞬间产生局部高温高压(5000K,1800MPa)。这些超声波所携带的能量足以打开结合强劲的化学键啊另外由于液哨中水流速度极快,也会产生“水力空化”现象0,即水流内部形成空穴、空洞或空腔当液体快速流动时,气泡就会不断的产生和溃灭,从而释放能量,产生局部高温高压。空化现象所产生的能量,可以对微生物细胞物质产生损伤,破坏其细胞质膜,从而导致细胞死亡1,因而也就能达到杀菌的效果。3实验部分3.1实验条件氯化钠(NaCl):分析纯,西陇化工股份有限公司;营养肉汤:国药集团化学试剂有限公司;污水取自城市河流:精密电子天平:天津市天马仪器厂:液哨超声发生器:自制;高压灭菌锅:浙江新丰医疗器械有限公司;水听器:型号CS3,中科院声学研究所;示波器:江苏扬中电子仪器厂,型号SR8;菌落总数测试片:广州绿洲生化科技有限公司。验使用自制的由液哨式超声发生器组成的循环冷却水杀菌系统,见图2。其中簧片的主要几何尺寸见表2,材料均为不锈钢。测定表明,该液哨超声发生器的入口水压为08MPa时,其流量最高为28m3h,杀菌实验在盛有100L污水的水槽中进行。压力長片明B区流量计泵循球冷却水图2循环冷却水杀荫系统Fig 2 Cooling water disinfection system化学反应工程与工艺2012年02月裹2簧片的结构参数Table Smctural parameters of Reed whistleLength/mmReed width/mm22222024ooomooo032液哨性能参数测定选取表2中的各种簧片,通过调节阀门改变出水口处的压力,将CS-3水听器直接放入液哨附近,另一端与示波器相连,读取各个压力下的振幅,利用下面公式求出声强:e/刎)式中:z为声强,Wm2;e为示波器显示电压幅值,V;m为换算系数,31.6,与探头本身的物理性有关:四为媒质的密度,kg/m3;c为媒质中的声速,m/s33杀菌实验取一定量在一定条件下培养好的细菌倒入水槽中,加生理盐水稀释,水温为26℃,调节液哨的性能参数1闻,根据性能测试的结果,使其达到最佳状态,开启水泵,调节阀门,使其水压维持在07MPa,运行60min。实验前后每10min取一次水样测其菌落总数。通过菌落总数测试片测试实验前后污水的细菌总数,杀菌率计数方法按下式w-wx100%M式中:形杀菌率:M,处理前菌落总数:M,处理后菌落总数4结果与讨论41簧片结构优化4.1入口水压、簧片厚度与声强的关系对表2中9组簧片进行逐测试,得出入口水压、簧片厚度对声强的影响,见图3(图中结构参数表示为簧片厚度(mm)x簧片长度(m)x喷距(mm))。取液哨簧片长度为12mm,喷距为4mm,改变入口压力,考察簧片厚度对液哨声强的影响实验过程中,当入口水压为0IMPa和02MPa时,未听见明显的哨声。这是因为入口压力较小时水流冲击簧片的力度很小,簧片的振动很弱,几乎没有明显的线状谱。从04MPa开始,开始有一种较为尖锐的声音。从实验数据可以看出,随着水压的增大,声强逐渐变强,并在07MPa时达到最大。同时可以看出,资片厚度为04mm和0.5mm时,所得的声强是比较大的,可以看出簧片的厚度会影响簧片的振动快慢和振幅大小。4.1.2入口水压、簧片长度与声强的关系保持液哨簧片厚度以及喷距不变,改变液哨入口压力,考察簧片长度对液哨液哨声强的影响从图4实验数据可以看出,簧片长度为12mm时,所得到的声强是比较大的,约23Wm2左右。可见并不一定是长度越长或越短,产生的声强越大,而是存在一个最佳点。第28卷第1期张陈成等.液哨超声在循环水杀菌的应用04nmx 12mmx4 mmsmmx16mmx4t58有28品0.00.10203d.406070809Hydraulic pressure/MPa图3簧片厚度对声强的影响图4簧片长度对产强的影响Fig 3 Relationship between thickness and sound intensityFig 4 Relationship between length and sound intensity4.3入口水压、喷距与声强的关系保持液哨簧片厚度和长度不变,逐步增加入口压力,考察喷距不同时对液哨声强的影响。从实验数据可以看出,随若确距改变得到的声强数据明显变化,所以喷距对空化强度有一定的影量响。并且簧片到喷口之间距离达到2mm时,所得的05声强数据是最大的。这主要是因为簧片越靠近喷口04050607Ds09时,水流冲击簧片的力度就越大,簧片的振幅也就越draulic pressure /MPa大,振动速度也越快。由图5结果可知簧片结构参数图5簧片到喷口的距离对声强的影响为04mm×12mm×2mm时声强最大。Fig 5 Relationship between distance and sound intensity42杀菌实验结果与讨论421处理时间对杀菌效果的影响根据液哨最佳结构参数优化的结果,选取两种簧片,一种性能最好的簧片04mmx12mmx2mm,另外一种性能次好的簧片尺寸为05mmx12mmx2mm,进行循环水杀菌实验,其中被处理的污水量为80L此时入口流量24mh、水压07MPa,。实验结果如图6。从图6中可以看出,液哨对循环冷却水灭菌是有效的,灭菌率分别达到了70%和84%可以看出结构参数最优的液哨对循环水起到较好的灭菌效果。图6处理时间对杀菌效果的能响图7处理温度对杀菌效果的蟛响Fig. 6 The effect of processing time on sterilization rate Fig. 7 The ettect of processing temperature on sterilization rate4.22温度对灭菌效果的影响考察温度对灭菌效果的影响设置15、2025以及30℃四种温度选取结构参数为04mmx12mm×2mm化学反应工程与工艺2012年02月的簧片,其中被处理的污水量为80L。考察不同温度条件下的灭菌效果,结果见图7。图中结果表明,温度升高对细菌的灭菌效果都有明显的提高实验数据表明,温度越高,灭菌率越高。当温度分别为15、20、25和30℃时,90min内,灭菌率分别为7%%、82%、85%和83%这主要是由于温度升高将使液体的表面张力系数和粘滞系数下降,从而导致空化域值下降,使空化易于发生,但是并不是温度越高越好,这是因为温度升高,蒸汽压将增大,使空化强度减弱。5结论a)根据液哨性能测试实验的结果,液哨本身尺寸簧片长度(mm)×簣片厚度(mm)x喷距(mm)为12mm×04mm×2mm时,所得到的声强是最高的,为325Wcm2。此时入口压力07MPa,流量24m3hb)循环水最佳水温为25℃,选取两组簧片,其中一组簧片经过性能测试,效果是最好的。杀菌处理60min,杀菌率分别是70%和84%参考文献:[应崇福超声学M北京科学出版社,1990495506团2]张帆吕效平韩萍芳,等超声用于循环冷却水火菌化工进展20113071431-1434Zhang Fan, Lu Xiaoping, Han Pingfang, et al. 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Study on catalyzing germicidal efficacy of ultrasound and nanomete titanium dioxide[]).Chinesel王振瀲李敏常用灭菌方法与TO2光催化灭菌机理的研究团周口师范学院学报200.20592%ang Zhenling. Li Min. Progress in study of bactericidal methods and TiO photocatalysis killing [] Joumal of Zhoukou Teachers College,203、205)9294[17 Dadjour M F, Ogino C, Matsumura S. et al. Kinetics of disinfection of escherichiacoli by catalytic ultrasonic irradiation with Tio U.Biochemical Engineering Jouma, 2005, 25(3):243-248下转86页化学反应工程与工艺2012年02月le xiaojing. Huang Xianliang, Wang Zhengbao. Characterization of acidic properties of AgNaZSM-5 catalyst [] Chemical ReactionEngineering and Technology, 2010, 26(4): 361-365,370I9陆铭,孙洪敏,郭螨等ZSMS沸石催化剂的失活历程和活性稳定性团石油学(石油加工2001,17(4)5963Lu Ming. Sun Hongmin, Guo Yu, et al. Study on deactivation process and actiwutu stability of ZSM-5 zeolite []. Acta Petroleiica(Petroleum Processing Section), 2001, 17(4): 59-631毛东淼,郭强胜,孟涛,等,水热处理村纳米H2SM5分子酸性及催化醇制丙烯反应性能的影响物埤化学学报.2010,26(2)38344Mao Dongsen, Guo Qiangsheng Meng Tao, et al. Effect of hydrothermal treatment on the acidity and catalytic performance of nanosizedHZSM-5 zeolites for the conversion of methanol to propene [] Acta Phys. Chim. Sin, 2010, 26(21: 338-344Effects of the Impurities in LPG on H-ZSM-5 Catalyst for MTP ProcessGao Xiujuan, Chen Aiping Tong Shan, Li Debing, Chen Yuanying, Sun Xuguang, Mei Changsong'( 1. Datang Inner Mongolia Duolun Coal Chemical Co. Ltd. Inner Mongolia 027300, China; 2. Datang Intemational ChemicalTechnology Research Institute Co, Ltd, Beijing 100070, China)Abstract: The homemade LPG contains trace amounts of impurities. Apparently, due to the contents of theimpurities much higher than those of the impurities restricted by the Lurgi MTP(methanol to propylenetechnology, the LPG can not be used as the substitute for the cycling hydrocarbons without any expinvestigation. In this paper, the effects of the impurities in LPG on the structure and performance of H-ZSM-5catalyst for mTP process were investigated. The results of the performance test of H-ZSM-5 catalyst showed thatthe mTP catalyst exhibited a high activity, anti-coking capability, and regeneration property under the condition ofco-feeding with methanol and LPG ICP measurements showed that the deposition of impurities did not occur onthe catalysts. XRD tests suggested that the framework structure of the catalyst maintained well after repeatedreaction or regeneration NH,tpD characterizations showed that the amount of weak acid sites of the catalyst didnot change after reaction or regeneration. Therefore the homemade LPG can be verified as the substitute for thecycling hydrocarbon of MTP process.Key words: Lurgi MTP process; H-ZSM-5 catalyst; LPG impurity; regeneration接74页Application of Liquid Whistle Ultrasonic Generatorfor Circulation Water SterilizationZhang Chencheng, Lu Xiaoping, Han PingfangNanjing University of Technology College of Chemistry and Chemical Engineering, Institute of Sonochemical Engineering.Nanjing 210009, China)Abstract: A new liquid whistle ultrasonic generator is studied. The sterilization experiments have been carried outwith this liquid whistle device, which use high-speed circulation water as a power source. We studied the effectsof different parameters, such as structure of reed whistle and the pressure of the circulating water, on sterilizationrate. The preferable structure of the reed whistle is 0.4 mmx12 mmx2 mm. The reed whistle operating conditionsshow as follows: 3.25 W/cm2sound intensity, 0.7 MPa water inlet pressure, 25 t water temperature and 2.4m/h water flow-rate for 60 min. Under these conditions, the sterilization rate reached up to 84%. The generatorhas various advantages such as simple structure, fine sturdiness, durability and large handing capacity as well aslow power consuming. Moreover, it is suitable for industrial applications.Key words: liquid whistle; ultrasound; sterilization