Rapid and real-time analysis of multi-component dissolved gas in seawater by Raman spectroscopy combined with continuous gas-liquid separator

Rapid and sensitive detection of dissolved gases in seawater is quite essential for the investigation of the global carbon cycle.Large quantities of in situ optical detection techniques showed restricted measurement efficiency,owing to the single gas sensor without the identification ability of multiple gases.In this work,a novel gas-liquid Raman detection method of monitoring the multi-component dissolved gases was proposed based on a continuous gas-liquid separator under a large difference of partial pressure.The limit of detection(LOD)of the gas Raman spectrometer could arrive at about 14 μl·L^(-1)for N_(2)gas.Moreover,based on the continuous gas-liquid separation process,the detection time of the dissolved gases could be largely decreased to about 200 s compared with that of the traditional detection method(30 min).Effect of equilibrium time on gas-liquid separation process indicated that the extracted efficiency and decay time of these dissolved gases was CO_(2)>O_(2)>N_(2).In addition,the analysis of the relationship between equilibrium time and flow speed indicated that the decay time decreased with the increase of the flow speed.The validation and application of the developed system presented its great potential for studying the components and spatiotemporal distribution of dissolved gases in seawater.

Evaluation of gas-liquid separation performance of natural gas filters

Fibrous filters are often used to remove contaminants including both dusts and liquid droplets from natural gas. This paper aims to evaluate the gas-liquid separation performance of three types of cartridge filters used in the West-East natural gas transmission project. The comparison of the original pressure drop of clean filters and the evolution of pressure drop as liquid droplets deposited in the filter media are described. The original pressure drops of these filters were similar but the pressure drops at a steady state were different. Fractional efficiency was used to study the separation performance of cartridge filters. Droplets at the outlet of the filters had small diameters, no more than 3 μm, but were very numerous. The effect of filtration velocity on gas-liquid separation performance was analyzed. Higher filtration velocity indicated better gas-liquid separation performance. Finally the quality factor related to pressure drop and filtration efficiency was applied to evaluate the gas-liquid separation performance.

DOUBLE LOOP ACTIVE VIBRATION CONTROL OF PNEUMATIC ISOLATOR WITH TWO SEPARATE CHAMBERS

A newly designed pneumatic spring with two separate chambers is promoted and double-loop active control is introduced to overcome the following drawbacks of passive pneumatic isolation： ① The low frequency resonances introduced into the system; ② Conflict between lower isolation frequency and stiffness high enough to limit quasi-static stroke;③ Inconsistent isolation level with different force load. The design of two separate chambers is for the purpose of tuning support frequency and force independently and each chamber is controlled by a different valve. The inner one of double-loop structure is pressure control, and in order to obtain good performance, nonlinearities compensation and motion flow rate compensation （MFRC） are added besides the basic cascade compensation, and the influence of tube length is studied. The outer loop has two functions： one is to eliminate the resonance caused by isolation support and to broaden the isolation frequency band by payload velocity feedback and base velocity feed forward, and the other is to tune support force and support stiffness simultaneously and independently, which means the support force will have no effect on support stiffness. Theoretical analysis and experiment results show that the three drawbacks are overcome simultaneously.

Effects of Expansion Chamber on the Flow Pattern and Performance of Cyclones

To improve the performance of the Stairmand cyclone, the effects of an expansion chamber on the flow field, the pressure drop and the separation efficiency were investigated numerically and experimentally. The experimental results showed that compared with the Stairmand cyclone, the cyclone with an upper expansion chamber worked better at low inlet velocity(less than 14 m/s in this study), while the cyclone with a lower expansion chamber achieved higher efficiency at a relatively high inlet velocity(14-20 m/s). The presence of an expansion chamber can generally result in a slight decrease in the cyclone pressure drop. The simulated results, which were used to further analyze the reason behind the experimental phenomena, suggested that the expansion chamber had insignificant effects on the tangential velocity profiles in the cylindrical part of cyclones. While in the cone part, the expansion chamber and the dipleg, the tangential velocity slightly decreased. Nevertheless, the expansion chamber decreased the possibility of the vortex end to sweep the wall and then reduce the particle re-entrainment. Therefore, installing the expansion chamber at a proper position could improve the separation performance of Stairmand cyclones. Both the experimental and simulated results represent a potential improvement of the Stairmand cyclone performance.

FLUID DYNAMICS IN A GAS-STIRRED LADLE——A Separated Flow Model with Stochastical Trajectories

A separated flow model with stochastical trajectories has been developed to describe the fluid flow in a bubble stirred ladle.The bubble dispersion,turbulent characteristics and gas-liquid interactions can be predicted by this mathematical model.The bubble flow as a dispersed phase is treated in a Lagrangian frame of reference and the analysis of the turbulent flow for liquid phase is conducted in a Eulerian field.The interactions between bubbles and liquid phases are considered as a bubble source term in the control equation for a continuous phase. The Monte Carlo sampling method is used to determine the bubble trajectories.The homoge- neous flow model is also taken into consideration so that it can be compared with the sepa- rated flow model.Numerical predictions using a water model of a ladle show that the pre- dicted results of the separated flow model agree satisfactorily with the experimental results, but the prediction of the homogeneous flow model are not in good agreement with the experi- mental results.

一种气田新型入口过滤分离装置的设计及应用

在天然气田脱水工艺中,采用三甘醇脱水工艺的天然气处理系统需通过入口过滤分离装置脱除固体杂质、重烃组分、游离水滴以减少下游脱水负荷。在日常生产中,传统入口过滤分离装置存在腔室液位无法稳定、管线节流冻堵、天然气窜入火炬罐等问题。经分析,传统入口过滤分离装置液位无法稳定的原因主要是液位调节阀压差大、集液腔体积小。针对此问题,提出一种新型入口过滤分离装置。现场应用结果表明,该装置能够有效增加入口过滤分离装置液位调节阀背压,缓冲上游来液冲击而保障其液位稳定,减少火炬放空气,节能减排效果良好,可在天然气田的三甘醇脱水工艺系统中广泛推广应用。

Investigation on Temperature Separation and Flow Behaviour in Vortex Chamber

In the previous researches, it is known that the swirl flow in circular pipe causes the temperature separation. Recently, it is shown that the temperature separation occurs in a vortex chamber when compressed air are pumped into this device from the periphery. Especially, in a cavity installed in the periphery of the chamber, the highest temperature was observed. Therefore, it is expected that this device can be used as a heat source in the engineering field. In recent researches, the mechanism of temperature separation in vortex chamber has been investigated by some researchers. However, there are few researches for the effect of diameter and volume of vortex chamber, height of central rod and position of cavity on the temperature separation. Further, no detailed physical explanation has been made for the temperature separation phenomena in the vortex chamber. In the present study, the effects of chamber configuration and position of the cavity on temperature separation in the vortex chamber were investigated experimentally.

Quantification of particle separation using electrostatically charged spray mist in a dust chamber

In order to improve the efficiency of reducing fine dust emissions from diffuse sources,the commonly used water mist can be electrostatically charged.Thus,the attraction between particles and droplets increases due to electrostatic field forces.In the experimental investigations carried out,an electrostatic two-fluid nozzle was used to generate a charged spray mist according to the principle of charging by induction.In a chamber,dispersed dust was precipitated with the spray mist,while detecting the laser light attenuation.By means of comparative measurements it could be shown that faster sedimentation and separation takes place through electrostatic attraction.Parameter variations regarding the use of compressed air and water were investigated and the sedimentation time of the particle-droplet mixture in the chamber was shown.A size distribution was then calculated from the laser light attenuation,which shows that the proportion of small particles decreases with spray application.Furthermore,the influence of the polarity of droplets and solid particles on the reduction measure was determined.

直流循环凝汽器回水室抽空气改造技术优化及应用

某电厂#1机组、#2机组均采用一次直流供水的开式循环冷却水系统,在机组正常运行的情况下,空气频繁进入凝汽器回水室,使循环冷却水虹吸高度降低,造成机组真空降低,甚至导致凝汽器循环冷却水回水系统虹吸损坏。为此,分析了凝汽器回水室频繁进空气的原因,并通过比较不同类型的凝汽器回水室抽空气改造方案,提出并实施了一种高效分离、全自动控制的凝汽器回水室抽空气改造方案,该方案有效解决了凝汽器回水室频繁进空气的问题。

外置式卷接机组梗签分离装置的设计

为降低成品烟丝中的梗中含丝率,减少烟丝浪费,在ZJ17卷接机组的基础上设计了一种外置式梗签分离装置。原机分离出的梗丝混合物进入梗签一次分离装置,在真空悬浮腔内将混合物再次分离;一次分离出的较重烟丝和梗签的混合物输送到除尘房,较轻烟丝输送到梗签二次分离装置,在离心分离腔内将混合物再次分离;二次分离出的较轻烟丝直接进入制烟环节,含有少量烟丝的梗签混合物进入吸尘室。利用Ansys Workbench14.0软件对两种真空悬浮腔进行仿真分析,结果显示:方形腔体的梗丝分离效果好于圆柱形腔体,风分气压范围为-1.8×10~5～-2.3×10~5Pa;将离心分离腔体设计为"马蹄形",有利于气流流速发生变化,减少烟丝造碎。以曲靖卷烟厂生产的"云烟(软珍品)""云烟(软紫)"两种卷烟牌号为对象进行测试,结果表明:(1)改进后ZJ17卷烟机组平均梗中含丝率从20.27%下降到1.80%,每台机组可节约烟丝3 180 kg∕年;(2)安装分离装置不会对烟支卷制质量产生影响。该装置可为提升卷烟厂精益生产水平提供支持。

联合收获机惯性分离室内气固两相流数值模拟

利用Fluent软件中K-ε湍流模型和离散相模型对4ZTL-1800气吸式联合收获机惯性分离室气固两相流特征进行数值模拟计算分析.从流体动力学和湍流理论出发建立了气相湍流模型,根据牛顿第二定律建立了固相数学模型.通过建立的模型和边界条件模拟气体流动,利用双向耦合拉格朗日法追踪颗粒运动轨迹.通过数值计算,得到气流场压力分布规律以及颗粒相运动轨迹及其沉降和分离过程.研究结果为进一步改善惯性分离室内流场的分布规律,提高籽粒的沉降效率,减少气流的携带损失提供了依据.

白内障超声乳化吸除联合房角粘连分离术治疗慢性闭角型青光眼合并白内障的临床疗效

目的观察白内障超声乳化吸除人工晶状体植入联合房角粘连分离术治疗慢性闭角型青光眼合并白内障的临床疗效及术后房角形态的改变。方法白内障超声乳化吸除人工晶状体植入联合房角粘连分离术治疗慢性闭角型青光眼61例(73只眼),对其手术前后的视力、眼压、视野、中央前房深度、房角形态进行对照,术后随访6～11个月。结果 61例(73只眼)中有69只眼视力较术前明显提高(P<0.05)。73只眼术后中央前房深度均加深,术前前房深度(1.572±0.314)mm,术后前房深度(3.186±0.217)mm(P<0.05)。66只眼术后眼压明显降低,术前眼压(22.42±3.53)mm Hg,术后眼压(13.52±3.24)mm Hg(P<0.05)。房角镜术后2个月检查有71只眼房角开放,术后6个月房角镜未发现房角再次粘连,64只眼术后6个月复查视野无缩小。结论超声乳化白内障吸除人工晶状体植入联合房角粘连分离术可有效降低眼压、提高视力,是闭角型青光眼同时合并白内障患者安全有效的治疗途径。

急性闭角型青光眼合并白内障手术治疗的疗效观察

目的:观察前房角分离白内障囊外摘除后房型人工晶状体植入联合青光眼小梁切除治疗原发性急性闭角型青光眼合并白内障的临床效果。方法:对29例(29眼)急性闭角型青光眼合并白内障行白内障囊外摘除后房型人工晶状体植入联合小梁切除术。结果:29例(29眼)术后前房深度增加,视力较前提高,术后无严重并发症。结论:前房角分离、白内障囊外摘除后房型人工晶状体植入联合小梁切除术可有效降低眼压,开放房角,提高视力,取得了良好的治疗效果。

斜板式气液重力分离技术研究

在简要叙述斜板式气液分离器斜板分离室内液滴分离原理基础上,以常规卧式气液分离器设计准则为基础,通过对实际情况的分析与简化导出气液两相分离的数学模型及斜板气液分离器结构设计计算公式。并对常规卧式分离器和斜板式气液分离器分别进行结构尺寸设计与分离效率的对比计算,得出斜板式气液分离器具有实际应用推广价值。

催化裂化用短接触旋流反应器内气固滑移特性

利用欧拉-欧拉双流体模型对短接触旋流反应器分离腔内气固滑移特性进行了数值模拟,主要研究了切向气固滑移速度的分布规律,并考察了操作参数和物性参数对分离腔内切向滑移速度的影响。计算结果表明,分离腔内切向气固滑移速度沿径向呈'驼峰'分布;当气相入口速度增大或者剂气比减小时,切向气固滑移速度变小,颗粒切向速度增大,离心力增大,有利于提高气固分离效率;颗粒密度对切向滑移速度分布影响不大;颗粒粒径较大时,在排尘口易出现堵塞,不利于长周期运行;建立了截面平均切向气固滑移速度计算模型,计算值与模拟结果误差在±7.0%以内。

蔬菜种子风力筛选机分离室气固两相流模拟与试验

分离室作为蔬菜种子风力筛选机的重要组成部分,其风机频率和风门开度对种子筛选分离的质量有着重要的影响。利用Fluent软件的RNG k-ε湍流模型和DPM离散相模型,仿真了物料在分离室中的运动过程。用多项式拟合法分析了仿真结果,获得工作参数(风机频率和风门开度)与清选性能(清洁率和损失率)的关系。在此基础上,对清洁率和损失率进行运算,得到清选效率,该指标全面综合地反映了不同工况下清选效果的优劣。由清选效率的三维图及其等值线图能够便捷地分析分离室的最优工作参数。通过以上方法,得到上海青种子、菠菜种子和小白菜种子最优工作参数。分别是风机频率35 Hz、风门开度75%;风机频率42 Hz、风门开度80%;风机频率36 Hz、风门开度80%,对应的清选效率分别是88%、84%和88%。设计实机验证试验,比较了不同工况下清选性能的仿真结果与试验结果,二者吻合度较高,证明了分离室气固两相流模型的可靠性。

基于CFD-DEM的收获机分离室内谷物运动模拟与试验

采用计算流体力学与离散元耦合的方法对割前摘脱稻麦联合收获机惯性分离室内谷物的运动进行数值模拟。仿真结果表明:籽粒和短茎秆在气流作用下能够实现分离,分离室入口气体速度增加,有助于提高分离室初清选谷物的性能,但入口气体速度增加使得分离室后部气体湍流现象加重,且能耗也随之增加;不饱满籽粒能在分离室内实现沉降。对仿真结果进行了试验验证,结果表明利用CFD-DEM对分离室内谷物运动进行数值模拟是可行的。

电选机电场强度与相对湿度之间的关系

为了研究电选机高压静电分选腔的电场强度与相对湿度之间的关系,设计了能产生高达100%相对湿度的高湿度发生器,并进行了不同相对湿度下粉煤灰电选效果的实验研究。结果表明,随着相对湿度的增加,电选机的分选效果变差,直至电场被击穿而使电选机无法正常工作。根据实验结果,引入相对湿度系数f2,对电选机高压静电分选腔电场强度的设计公式进行了修正,以求电选机高压静电分选腔的设计更为科学。

气吸式割前摘脱联合收割机惯性分离室压力损失的影响因素

鉴于气吸式4ZTL-1800割前摘脱稻(麦)联合收获机的惯性分离室的体积和压力损失一般都较大。该文在前期研究工作基础上,确定以惯性分离室为对象,选择隔板长度、上盖安装高度、分离室长度、分离室入口气体速度为试验因素,以压力损失为评价指标,进行了四因素五水平二次正交旋转组合试验,获得了上述参数对压力损失的影响规律。在保证分离室分离效率的前提下,以分离室压力损失最小为目标,得出了惯性分离室的优化结构参数:隔板长度1180 mm,上盖高度1120 mm,分离室长度1700 mm。研究结果可为惯性沉降分离室的设计提供参考。

不同燃烧室长度的旋转爆震发动机实验研究

为了研究燃烧室长度对旋转爆震发动机(RDE)推力和比冲的影响,设计了RDE推力试验台,以环形燃烧室内径和外径分别为70mm和80mm的RDE作为实验模型,发动机采用环缝-喷孔对撞式掺混方式,以H2和Air分别作为燃料和氧化剂,使用高能火花塞直接点火,并用压电式力传感器测量推力,实验研究燃烧室长度分别为40mm,60mm,90mm和120mm的发动机工作性能。通过实验发现,燃烧室长度对RDE稳定工作的工况范围有很大的影响;在稳定工作的工况范围内,燃烧室内的爆震波的传播速度及RDE的推力和比冲随着入口质量流量的增大而逐渐提高,而当量比和燃烧室长度均存在一个最佳值,使爆震波的传播速度及RDE的推力和比冲达到最大值。针对于本论文中的RDE实验模型,基于混合物的比冲最高能够达到74.61s。