摘要
钛白粉是一种白色无机颜料,化学性质稳定,广泛应用于涂料、塑料、橡胶、油墨、纸张、化纤、陶瓷、日化、医药、食品等行业。在其工业生产中,存在圆盘洗涤工艺,通常需要大量的水对物料进行水洗操作。喷射器作为一种流体机械,在许多工业领域中都有应用,但较少应用于节水。本文着重对四川攀枝花兴中钛业公司生产钛白粉的用水工艺进行改进,将先前传统的圆盘洗涤,改为使用节水清洗元件的圆盘洗涤,并对节水清洗元件的性能进行了理论分析及实验研究,研究了影响节水清洗元件性能的主要因素,最后对节水清洗元件在圆盘洗涤工艺中的应用及经济效益进行了分析。
本项研究提出的节水清洗元件,使用喷射器原理,利用压力水来引射空气,使气、水在混合室均匀渗混成气-水两相流,而两相流的音速大大地低于单相流,当流体从亚音速变为超音速时,要产生激波,使两相流进一步增压,达到容积流量和射流速度同时增大的效果,起到节水的作用。
论文首先对节水清洗元件的节水性能进行理论分析。研究表明,节水性能可由喷射系数表征,喷射系数越大,节水效果越好,而影响喷射系数的主要因素,包括面积比、工作压力、引射压力及出口压力等。文中给出了这些影响因素改变时对于喷射系数影响的具体表达式,并分析了这些因素的影响大小。
文中还建立了一套以水(工作流体)和空气(引射流体)为介质的节水清洗元件实验台,根据理论分析,初步拟定实验用的节水喷射器的几何尺寸、出入口通径、喉部通径、引射口大小;改变喷嘴出口直径和混合腔孔径,实验研究了节水喷射器基本参数对其性能的影响,并根据喷射系数得到最佳尺寸搭配,对节水清洗元件的结构进行了初步优化。
最后,结合四川攀枝花兴中钛业钛白粉生产工艺的实际情况,根据圆盘洗涤工艺运行过程,将节水清洗元件应用于圆盘洗涤工艺中,并根据节水试验结果对节水清洗元件的应用效果进行了经济性分析。
Titanium dioxide pigment (TiO_2) is a kind of white powder with high opacity, brilliant whiteness, excellent covering power and resistance to color change. These properties have made it a valuable pigment and opacifier for a broad range of applications in paints, plastic goods, inks and paper. During the production procedures of Titanium dioxide pigment, raw materials need washing and cleaning by much water in order to get rid of the impurities. As a fluid machine, ejector is widely applied in industries but few used as water-saving device. In this paper we are engaged in the performance analysis and experimental investigation of the ejector which is used as water-saving component in disc filter cleaning process within TiO_2 production procedures of Xingzhong Titanium Co. in Panzhihua, Sichuan province. By theoretical and experimental research, the main factors governing the performance of water-saving component are determined, and application and economy analysis of water-saving component in disc filter cleaning process are made.
The water-saving component is on the basis of ejector theory of fluid dynamics knowledge. When the component works, it is injected with the pressure water as motive fluid and the air from surroundings as suction fluid, then water and air meet with each other and turn out to be gas-liquid two phase flow in the mixing section. While the speed of sound in two phase flow is much lower than it in single phase flow, that is to say that the subsonic flow, including motive fluid and suction fluid, turn out to be the supersonic flow, i.e. the gas-liquid two phase flow; when shock wave occurs, through which pressure of the two phase flow increase abruptly. Accordingly, when water get through the water-saving component, both the flow rate and the velocity of work fluid out of it increase, and the function of it comes into effect.
Firstly, we theoretically analyze the performance of water-saving component, which depends on the entrainment ratio of it. The more the value of entrainment ratio of water-saving component is, the greater the effect upon water-saving is. The results show that there are many relations among entrainment ratio, ejector configuration and operating parameters, including area ratio, working pressure, ejecting pressure and outlet pressure. The expressions of parameters are obtained in this paper, and how the variables affecting are also analyzed.
Secondly, test-bed of water-saving component is set up, with water as motive fluid and air as suction fluid. According to the theoretical performance analysis of water-saving component, the property parameters of it are studied and the configuration of it is designed. In the experiment investigation, we study that how the water-saving performance of ejector is affected by parameters, viz. the nozzle, the absorber, the mixing-chamber, and the diffuser, and the optimal performance of water-saving component is concluded. According to the optimal performance of water-saving component, the optimal configuration of it is made.
Finally, according to the actual TiO_2 production procedures of Xingzhong Titanium Co., the water-saving component is experimentally applied in the disc filter cleaning process, and economy analysis of it in disc filter cleaning process is made.
引文
[1]邓捷,吴立峰.钛白粉应用手册(修订版)[M].北京:化学工业出版社,2005.
[2]陈朝华,刘长河.钛白粉生产及应用技术[M].北京:化学工业出版社,2006.
[3]索科洛夫,津格尔著,黄秋云译.喷射器[M].科学出版社,1977.
[4]许跃华,段守荣.攀枝花城市水资源利用现状与可持续利用对策[J].四川水利,2004,(4):51-54.
[5]王滞.水资源的可持续利用[J].科技广场,2002,(12):21-28.
[6]戴万红.水处理工业的现状与展望[J].冶金译丛,1999,(3):95-97.
[7]董辅祥,董欣东.节约用水原理及方法指南[M].中国建筑工业出版社,2000.
[8]陆宏圻.射流泵技术的理论及应用[M].北京:水利电力出版社,1989.
[9]Elord H G.The theory of ejector[J].Journal of applied mechanics,Trans.ASME,1945,67:170-174.
[10]刘志强,沈胜强,李素芬.喷射器一维设计理论的研究进展[J].热能动力工程,2001,16(3):229-232.
[11]流体工程学会喷射技术专业委员会.我国喷射技术应用发展概况[J].流体机械,1988,(11):27-28.
[12]黄晨,赵在三.喷射器在我国热能及动力工程中的应用[J].动力工程,1988,(4):53-58.
[13]郭金基.亚音速气体喷射器的性能分析及其计算方法[J].中山大学学报自然科学版,1981,(1):20-31.
[14]沈胜强,李素芬等.喷射式热泵的设计计算与性能分析[J].大连理工大学学报,1998,38(5):558-561.
[15]沈胜强,李素芬.纸机干燥部多段通汽系统中喷射式热泵的性能分析[J].中国造纸,2000,(2):36-40.
[16]刘志强,沈胜强等,蒸汽喷射式热泵性能实验研究[J].大连理工大学学报,2001,41(3):310-313.
[17]Keenan J H,Neumann E P.A simple air ejector[J].Journal of Applied Mechanics,Trans.ASME,1942,64:75-81.
[18]Keenan J H,Neumann E P,Lustwerk F.An investigation of ejector design by analysis and experiment[J].Journal of applied mechanics,Trans.ASME,1950,72:299-309.
[19]Sun D W,Eames I W.Recent developments in the design theories and application of ejectors-a review[J].Journal of the Institute of Energy,1995,68:65-79.
[20]陆震,尉迟斌等.蒸喷热泵的技术及其在化纤棉浆蒸煮工艺中的应用[J].能源研究与信息,10(2):18-22.
[21]上海市能源研究会.蒸汽喷射式热泵的应用与节能效果[J].能源研究与信息,10(2):36-41.
[22]阎尔平.蒸汽喷射式热泵供热在工业节能中的应用[J].节能技术,1994,(1):18-24.
[23]王成栋,庄琦.引射器用作化学氧碘激光器压力恢复系统的探讨[J].强激光与粒子束,1997,9(2):245-248.
[24]Karl Willian Felson.Experimental investigation of an ejector scramjet RBCC at mach 4.0 and 6.5 simulated flight conditions[D].The University of Alabama in Huntsville,2002.
[25]Annamalai K,Visvanathan K,Sriramulu V,Bhaskaran,K.Evaluation of the performance of supersonic exhaust diffuser using scaled down models[J].Experimental Thermal and Fluid Science,1998,17(3):217-229.
[26]张华.混合与扩散同时进行的环形引射器系统引射性能实验研究[J].北京航空航天大学学报,1993,(1):85-94.
[27]Dutton J C,Mikkelsen C D,Addy A L.A theoretical and experimental investigation of the constant area supersonic-supersonic ejector[J].AIAA Journal,1982,20(10):1392-1400.
[28]Jelinek M,Levy A,Borde I.Performance of a triple-pressure-level absorption cycle with R125-N,N'-dimethylethylurea[J].Applied Energy,2002,71(3):171-189.
[29]Adnan S(o|¨)zen,Mehmet(O|¨)zalp.Performance improvement of absorption refrigeration system using triple-pressure-level[J].Applied Thermal Engineering,2003,23(13):1577-1593.
[30]Giuseppe Grazzini,Andrea Rocchetti.Numerical optimization of a two-stage ejector refrigeration plant[J].International Journal of Refrigeration,2002,25(5):621-633.
[31]Wimolsiri Pridasawas,Per Lundquist.An exergy analysis of a solar-driven ejector refrigeration system[J].Solar Energy,2004,76(4):369-379.
[32]Selvaraju A,Mani A.Analysis of a vapor ejector refrigeration system with environment friendly refrigerants[J].International Journal of Thermal Sciences,2004,43(9):915-921.
[33]Selvaraju A,Mani A.Analysis of an ejector with environment friendly refrigerants[J].Applied thermal Engineering,2004,24(5-6):827-838.
[34]Riffat S B,Gan G,Smith S.Computational fluid dynamics applied to ejector heat pumps[J].Applied Thermal Engineering,1996,16(4):291-297.
[35]林兆福编.气体动力学[M].北京:航空航天大学出版社,1988.
[36]孙奉仲,吕伟,李淑英.水喷射器的引射系数分析[J].水动力学研究与进展,1997,12(4):414-418.
[37]杨绍利,盛继孚编著.钛铁矿熔炼汰渣与生铁技术[M].北京:冶金工业出版社,2006.
[38]Murphy J.Additives for plastics handbook[M].Holland:Elsevier,2001.
[39] Ladislav Svarovsky. Solid-liquid separation[M]. Holland: Elsevier, 2001.
[40] Sree Harsha K S. Principles of vapor deposition of thin films[M]. Holland: Elsevier, 2005.
[41] Watson J L, Li Zhicheng. Application of magnetic forces to disk vacuum filtration in the laboratory and plant[J]. Minerals Engineering, 1999, 12(10): 1253-1262.