旋流组合式进料喷嘴雾化性能实验研究

针对6种构型的旋流组合式进料喷嘴的雾化性能进行了实验研究。采用相位多普勒粒子分析仪(PDPA)测量了雾化粒径,同时验证了喷嘴的雾化角和各段的压降分配方案。结果显示:该旋流组合式喷嘴雾化效果较好,雾化粒径的空间分布比较均匀,各构型喷嘴在测量范围内的雾化粒径在63—76μm;喷嘴雾化粒径在流量20%操作弹性范围内的变化均在6μm之内;气液质量比从6%增加到7%会减小雾化粒径增加喷射速度;喷嘴压降分配合理,且采用四组合式旋流器以及球头双槽互击喷头的喷嘴压降分配较优。     

科技动态

重油催化裂化新型进料雾化喷嘴通过鉴定　　由中国石化集团北京设计院、西北工业大学、中国石化集团荆门石油化工总厂、锡山市石油化工设备总厂共同开发研制的重油催化裂化ＢＷＪ型进料雾化喷嘴 ,近日通过了中国石化集团公司技术开发中心组织的鉴定。ＢＷＪ型双流体离心式喷嘴 ,其核心技术是采用独创的两相旋流器 ,实现液流的均匀雾化。合作单位在开发研制过程中 ,经过优选 ,确定了性能优良的喷嘴结构 ,在此基础上根据不同处理量优化了结构尺寸 ,形成了设计系列并建立了完善的设计计算方法。冷态试验表明 ,产品雾化性能优越 ,喷嘴压降低 ,雾…     

基于正交设计的旋流组合式喷嘴雾化性能实验

为寻求旋流组合式喷嘴雾化性能影响因素间的优化匹配方案,在分析和总结的基础上,选取旋流器的组合方式、喷头构型、进气流量和进气方式等作为主要影响因素,通过正交设计理论,安排试验方案,采用相位多普勒粒子分析仪（PDPA）对雾化性能的关键评判因素——喷雾场粒径进行了采集测量。实验结果的极差分析和方差分析表明,旋流器的组合方式对雾化粒径的影响最强,水流量次之,再次为喷头构型,而进气方式的影响最弱;此外,旋流器组合方式与喷头的交互作用产生的影响不应被忽略。     

催化裂化进料喷嘴技术的研究进展

综述了催化裂化进料喷嘴的作用及特点,详细介绍了喉管类、靶式类、气泡雾化类、旋流式类、三次雾化类、气动雾化和气泡雾化结合类等进料喷嘴的结构特点、雾化机理及雾化效果。进料喷嘴的发展方向是深入了解气液两相流理论和气液初始作用,以及喷雾场存在雾化不均匀性,进一步研究出口形式使雾化粒度合适,压降分配合理。     

催化裂化装置对CS-Ⅱ型新型喷嘴的应用分析

催化裂化进料喷嘴,特别是重油催化裂化进料喷嘴,是催化裂化关键设备之一。进料喷嘴性能的优劣对裂化反应产品分布起着重要作用,性能优越的喷嘴可以改善进料喷嘴的雾化性能,减轻设备结焦,延长装置运行周期。随着原油趋于重质化,催化裂化原料油趋于劣质化,增加了原料油在反应时的裂化难度,可能造成设备结焦。     

低压旋流雾化喷嘴的雾化性能

石灰浆液雾化喷嘴是烟气喷雾干燥脱硫系统的关键设备。利用Win212-2型激光粒度分析仪,对不同结构参数的低浓度石灰浆旋流雾化喷嘴的低压雾化性能进行了实验研究,得出了喷嘴结构参数对喷嘴雾化性能的影响规律和石灰浆低压旋流雾化喷嘴的最优化结构参数。优化后的喷嘴结构参数为：旋流片槽数为4,旋流片槽张角6°,旋流室收缩角90°,D/d=4.4～6.4,D/b=6～8,L/b=3.3～4.0。该喷嘴在0.8 MPa的低压下,雾化粒度可达到100 μm以下,雾化角为70°左右,具有良好的雾化性能,比普通喷嘴的雾化性能有较大提高。     

地沟油生物柴油在旋流喷嘴中的雾化实验及模拟

对地沟油生物柴油在旋流雾化喷嘴中的内部流场及外部流场进行数值模拟,考察了喷嘴孔径、旋流芯螺距、螺柱槽道横截面积和槽道形状等结构参数对出口雾化速度及索特平均直径的影响,通过实验对模型进行了验证。结果表明,0.7 mm孔径的喷嘴的韦伯数最大,索特平均直径与雾化锥角最优。螺距4 mm的喷嘴雾化特性最优,旋流芯螺距越小,流体在喷嘴内旋流次数越多,阻力损失越大,流体在切向分量上速度越大。梯形槽道的雾化效果最好,相同横截面积下槽道的水力直径越大,雾化效果越好;截面积1 mm2槽道的喷嘴最优,槽道横截面积越小,流体在槽道中的湍流程度越大,流体内部剪切应力越大,液体表面不稳定波急剧增大。     

旋流式压力雾化器的研究应用

介绍了旋流组合式压力雾化器的结构原理，并通过对旋流式单喷嘴压力雾化特性的理论和试验研究，得出了组合式喷嘴雾化的特征参数。采用计算流体力学(CFD)技术，对喷雾干燥塔内气、固、液3相流场加以分析，优化了干燥系统的结构及工艺配置参数。以碱式硫酸铬为干燥对象，经工业化应用证明：采用该雾化装置的压力喷雾干燥系统在保证产品质量的前提下，可替代离心喷雾干燥装置，设备投资省，体积蒸发强度高，节能效果好。     

KH-5型喷嘴在重油催化裂化装置上的应用

通过对玉门炼油厂化工总厂0．8Mt／a催化裂化装置原料进料BWJ-Ⅲ型喷嘴研究,发现原料进料BWJ-Ⅲ型喷嘴雾化效果差、雾化蒸汽用量大、结焦率高、进料存在偏流等缺陷。针对此情况,2011年9月对原料BWJ—Ⅲ型喷嘴分段进料进行改造。改造后的KH-5型喷嘴环形进料,原料进料雾化效果显著提高,雾化蒸汽用量减少53％,掺渣率提高4．20％条件下,焦炭产率降低1．32％。     

催化裂化用新型高效雾化进料喷嘴的研制与工业应用

介绍了BWJ(Ⅲ)型流化催化裂化（FCC）用新型高效雾化进料喷嘴的研制和工业应用。工厂应用标定表明,采用该新型喷嘴,生焦率降低0.95%,干气收率降低0.475%,液体收率（液化气+汽油+柴油）提高1.432%,雾化蒸汽用量有所降低,说明喷嘴的雾化性能较好,经济效益显著。     

Diffusion of feed spray in fluid catalytic cracker riser

For fluid catalytic cracker (FCC) riser reactor, the diffusion pattern of feed spray and the flow features of catalysts in the feed injection zone were investigated in a cold‐riser model that is made of 186‐mm ID plexiglass pipe. In the feed injection zone, when a feed spray is introduced into the riser, a secondary flow of spray will occur. The secondary flow extends at first and then merges into the mainstream of spray. The occurrence of the secondary flow enhances the mixing of catalysts with feed. However, the extension of the secondary flow causes a violent catalyst backmixing; it is believed to be harmful to FCC reaction. The generation of the secondary flow of feed spray was theoretically analyzed by using the Kutta‐Joukowski Lift Theorem. Furthermore, a FCC feed nozzle, which can control/utilize the secondary flow in riser, was proposed. The effects of the nozzle used in some commercial FCC units are quite desirable. © 2009 American Institute of Chemical Engineers AIChE J, 2009     

Design and performance evaluation of swirl injectors for water evaporation at low pressure

This paper describes the design and performance evaluation of swirl injectors which find application in the spray flash desalination system at low pressures and temperatures. Water was sprayed into the vaporizer through a swirl injector as fine droplets. The vaporizer was maintained at low pressure. The maximum flow rate was 1 l/s. The injector performance was determined at different feed water temperatures, vacuum and water injection pressures. The effects of injector dimensions and flow parameters on droplet production were studied and analyzed. Droplet size of 0.7–0.9 mm from the theory compared with the experiments estimates. From this study, it is established that the droplet diameter in the range of 0.7–0.9 mm is optimum for flashing.     

Effect of feed atomization on FCC performance: simulation of entire unit

Entire fluid catalytic cracking (FCC) unit, comprising of a riser and a regenerator, is simulated by integrating FCC riser model presented in our earlier work (Chem. Eng. Sci. 56 (2001) 4489) with an FCC regenerator model. The effect of feed atomization (quantified by average drop size generated by the feed nozzle) on the performance of the unit is evaluated.     

自然吸气式浮选旋流器结构理论分析及实验研究

提出了最新结构的自然吸气式浮选旋流器。分析了结构特点及浮选原理,利用流体力学理论对射流喷嘴作了理论分析,并确定了该喷嘴的最佳结构及主要参数,通过实验确定了入料压力是影响旋流器处理量及浮选效果的主要参数,即入料压力越高,旋流器的处理量就越大,入料压力对浮选效果的影响,其最佳压力大小需经实验加以确定。     

Flow characteristics of a laminar swirling impinging jet: A numerical study

The primitive Navier-Stokes equations were solved to predict the flow field induced by a partially confined swirling laminar jet impinging normally on a flat surface. A study is made of the influence of the jet Reynolds number, nozzle-to-plate spacing, axial and swirl velocity profiles at nozzle exit plane, size of the confining and impingement plate and uniform suction applied at the plate. An interesting feature of the flow configuration is the predicted development of a recirculation bubble in the stagnation region which influences the heat and mass transfer characteristics. Axial and swirl velocity profiles at entry have dominant influence on the development of the flow field.     

CS喷嘴在催化裂化装置的工业应用

介绍了CS喷嘴在120×10^4t/a催化裂化装置的应用情况。工业试验结果表明,在原料油性质、催化剂性质和操作条件基本相同的情况下,使用CS喷嘴后,改善了产品分布,降低装置运行费用。干气收率降低了1.5个百分点;焦炭收率降低了1.2个百分点;液化气产率提高了1.3个百分点;汽油产率提高了1.1个百分点;柴油产率提高了0.3个百分点。CS喷嘴对产物性质无不良影响。年增加综合经济效益6 126万元。     

Numerical simulation of cavitation in the conical-spray nozzle for diesel premixed charge compression ignition engines

The conical-spray injector is capable of achieving lean mixture with high homogeneity in the cylinder for diesel Premixed charge compression ignition (PCCI) engine with advanced injection timing. To better understand the cavitating flow inside the conical-spray injector, numerical simulations have been conducted by using a mixture multiphase model and a full cavitation model in this study. The results indicate that the cavitation evolution significantly affects the liquid sheet thickness and velocity at nozzle exit, which further change the spray angle and droplet Sauter mean diameter (SMD) dramatically. Based on the cavitation distribution inside the nozzle, the cavitating flow inside the conical-spray nozzle can be classified into four regimes with no cavitation, cavitation inception at inlet, developing cavitation at nozzle exit and super cavitation respectively. The extension of cavitation to nozzle exit in the super cavitation regime significantly improves the fuel atomization by increasing the injection velocity and decreasing the thickness of the liquid sheet. A cavitation map for the conical-spray injector has been developed by sweeping the ambient pressure and injection pressure simultaneously. It is found that the phenomenon of super cavitation only occurs in a narrow region where ambient pressure is very low. Therefore, the start of injection timing should be kept well before top dead center (TDC) to ensure the occurrence of super cavitation inside the nozzle in order to provide more homogeneous fuel/air mixture for diesel PCCI engines.     

Biodiesel influence on tribology characteristics of a diesel engine

This paper deals with the influence of biodiesel on some tribology characteristics of a bus diesel engine with a mechanically controlled fuel injection system. The tests have been performed on a fully equipped engine test bed, on a fuel injection test bed and on a discharge coefficient testing device. The tested fuel was neat biodiesel produced from rapeseed. Attention was focused on the biodiesel influence on the pump plunger surface roughness, on the carbon deposits in the combustion chamber, on the injector and in the injector nozzle hole. The pump plunger surface was analyzed by experimentally determined roughness parameters and by a microscope. The carbon deposits at fuel injector and in the combustion chamber were examined using endoscopic inspection. The deposits in the injector nozzle were investigated indirectly by measuring the nozzle discharge coefficient. Numerical simulation has been performed in order to estimate the influence of the discharge coefficient variation on the computed injection characteristics. The obtained results indicate that biodiesel usage may even improve the pump plunger lubrication conditions. Furthermore, the carbon deposits in the combustion chambers did not vary significantly in quantity but they were noticeably redistributed. Finally, it was found out that the variation of the nozzle discharge coefficient has to be taken into account only if high accuracy of numerical simulation is desired.     

催化裂化再生器树枝状气体分布器喷嘴的射流特性

在催化裂化装置中再生器底部通常设置有树枝状管式气体分布器,通过分布器上的喷嘴分布气体。但在实际运行过程中喷嘴常出现布气不均和磨损问题,影响其自身的布气性能和使用寿命。为此,在二维床实验装置上针对喷嘴的射流特性进行了实验研究。实验物料为FCC催化剂颗粒,喷嘴出口气速范围为30～70 m·s^-1,喷嘴喷射角度范围为0°～67.5°。实验用摄影观察法测量喷嘴射流的射流长度和附近的流场流态。实验结果表明射流长度随喷嘴气速和喷射角度的增大而变长。射流气体在向上翻转过程中,在树枝状管式气体分布器两分支管之间产生旋转涡流现象,旋转涡流的大小与喷嘴出口气速和安装角度有密切关系。最后基于实验数据,建立了喷嘴射流长度的计算模型。     

喷嘴进料对提升管进料段内颗粒浓度分布的影响

在提升管冷模实验装置上考察了喷嘴进料对颗粒浓度径向分布的影响规律. 结果表明,提升管进料段内存在3种形式的颗粒浓度径向分布,在距喷嘴较近的轴向区域,颗粒浓度沿径向呈明显的W形分布,喷嘴进料对颗粒流动的影响很强;在距喷嘴较远的轴向位置,颗粒浓度沿径向呈环-核分布,喷嘴进料对颗粒流动的影响很弱;在二者之间,颗粒浓度沿径向呈弱W分布,喷嘴进料对颗粒流动具有一定影响. 随着喷嘴气速的增加或预提升气速的减小,颗粒浓度逐渐由W形分布转变为环-核分布,喷嘴进料对颗粒流动的影响逐渐减弱. 采用喷嘴射流动量与预提升来流动量比Mj/Mr考察了操作参数及装置结构尺寸对提升管进料段内颗粒浓度径向分布的综合影响. 在实验范围内,动量比对进料段内颗粒浓度径向分布及颗粒流动行为具有明显的影响规律,随着动量比的增加,颗粒浓度逐渐由W形分布转变为环－核分布,操作参数及装置结构尺寸对颗粒流动的影响逐渐减小. 在动量比小于4.21时,操作参数及装置结构尺寸对颗粒流动的影响在H=0.675~1.075 m间的轴向位置基本结束;在动量比增大为4.21时,操作参数及装置结构尺寸对颗粒流动的影响在H=0.375~0.675 m间的轴向位置便已基本结束.