Study on Treatment of the Pesticide Wastewater by the Composite Process of Biological Active Carbon Filter-Fluid Bed

[ Objectlve] The research aimed to study treatment effect of the pesticide wastewater by the composite process of biological active car- bon filter-fluid bed. [Method] The composite process of biological active carbon filter- fluid bed was applied to treat the mixed pesticide wastewater. The removal efficiencies of CODcr, BODs, NH3-N, SS and the influence factors were investigated. [ Result] The composite process had good treatment efficiency for pesticide wastewater. After running stably, the average removal rates of CODc,, BODs, NH3-N and SS were re- spectively 91.6%, 96.2%, 90.2% and 87.5%. All indices reached the third level cdteda specified in Comprehensive Standard of the Sewage Dis- charge （DB12/356-2008）. [ Conclusionl The whole system operates reliably and simply, and provides a stable, convenient and economical solu- tion for deep treatment of the mixed pesticide wastewater.

Treatment of Dyes Wastewater by a New Kind of Bio - Fluid Bed

A new kind of bio-fluid bed used to treat dyes wastewater is described in detail due to its several special features,such as high removal efficiency,simple struc-ture,shock load resistance,etc.By means of analyzing the experiment data,the results show that the dye wastewater’s organic matter is removed greatly after be-ing treated by this new kind of bio-fluid bed.On the other hand,the removal efficiency of chromaticity of

A Preliminary Research on a Plasma Spout-Fluid Bed Reactor

A laboratory-scale plasma spout-fluid bed reactor with a 10 kW DC plasma torch was developed and tested using quartz sand particle and rice hull. The preliminary experimental results including particle recirculation and attrition, bed temperature distribution and stability, as well as biomass gasification system energy balance were presented in this paper. Research results indicated that plasma spout-fluid bed reactor may be a technically feasible reactor for carbonaceous organic material gasification.

Study of Diffusion through the Skin of Coated L-Ascorbic Acid by Fluid Bed Technology

Coating protects substances such as L-ascorbic acid from natural processes like oxidation. In this study, L-ascorbic acid was coated by fluid bed technology. A pH-dependent polymer was used as a coating material in order to release L-ascorbic acid (dissolution above pH 5.5) under conditions closest to the skin’s natural condition. Different techniques were used to determine the coating (SEM and size distribution) and to evaluate the percentage of coated L-ascorbic acid and its diffusion through the skin.

Fluidised bed granulation of two APIs:QbD approach and development of a NIR in-line monitoring method

The study focused on the fluid-bed granulation process of a product with two active pharmaceutical ingredients,intended for coated tablets preparation and further transfer to industrial scale.The work aimed to prove that an accurate control of the critical granulation parameters can level the input material variability and offer a user-friendly process control strategy.Moreover,an in-line Near-Infrared monitoring method was developed,which offered a real time overview of the moisture level along the granulation process,thus a reliable supervision and control process analytical technology(PAT)tool.The experimental design’s results showed that the use of apparently interchangeable active pharmaceutical ingredients(APIs)and filler sorts that comply with pharmacopoeial specifications,lead to different end-product critical attributes.By adapting critical granulation parameters(i.e.binder spray rate and atomising pressure)as a function of material characteristics,led to granules with average sizes comprised in a narrow range of 280–320μm and low nongranulated fraction of under 5%.Therefore,the accurate control of process parameters according to the formulation particularities achieved the maintenance of product within the design space and removed material related variability.To complete the Quality by design(QbD)strategy,despite its limited spectral domain,the microNIR spectrometer was successfully used as a robust PAT monitoring tool that offered a real time overview of the moisture level and allowed the supervision and control of the granulation process.

Numerical simulation of gas-solid flow with two fluid model in a spouted-fluid bed

The flow characteristics in a spouted-fluid bed differ from those in spouted or fluidized beds because of the injection of the spouting gas and the introduction of a fluidizing gas. The flow behavior of gas-solid phases was predicted using the Eulerian-Eulerian two-fluid model （TFM） approach with kinetic theory for granular flow to obtain the flow patterns in spouted-fluid beds. The gas flux and gas incident angle have a significant influence on the porosity and particle concentration in gas-solid spouted-fluid beds. The fluidizing gas flux affects the flow behavior of particles in the fountain. In the spouted-fluid bed, the solids volume fraction is low in the spout and high in the annulus. However, the solids volume fraction is reduced near the wall.

Industrial application of the technique of removing Mo by a combination of moving packed bed and fluidized bed ion exchange

The application of the technique of removing molybdenum by moving packed bedand fluidized bed ion-exchange in a factory was described. The data showed that the Mo removalefficiency is above 99 percent, and the Mo content in APT (Ammonium Paratungstate) is controlledsteadily below 18 X l0^(-6), in the case of treating the feed liquor containing Mo 1.4 g/L. Thetechnique is simple and convenient in operation, good reusability of resin, loss consumption ofdesorption reagent and little pollution on environment. The loss of tungsten is less than 0.5percent. The technique bas been proved to be an economical and efficient process for Mo removal.

Influences of the fluidizing and spouting pulsation on particle motion in spout-fluid beds

Effects of variable airflow on particle motion in spout-fluid beds are studied. Computational fluid dynam- ics using Navier-Stokes equations for the gas phase coupled with the discrete element method using Newton＇s laws for the solid phase have been employed. Results indicate that increasing the fluidizing velocity diminishes dead zones and increases both the total height of the bed and the traversed distance by particles in the steady spout-fluid bed. In pulsed airfows, two configurations are investigated, namely, the spouted pulsed-fluidized bed with pulsed flow of the fluidizing velocity, and the pulsed-spouted flu- idized bed with pulsed flow of the spouting velocity. The positive effect of pulsation on particle motion is shown and the effects of parameters, such as amplitude and frequency, on the dynamics of the bed are investigated in each configuration. An increase of up to 19% in traversed distance is found for the range studied, which suggests flow pulsation as a promising technique for increasing particle mixing in spout-fluid beds.

Investigation on Technique for Ethylene Preparation via Catalyzed in Fluidized Bed Dehydration of Bioethanol

The V-P/HZSM-5 catalyst was prepared by impregnation method using HZSM-5 zeolite as the carrier.Its catalytic activity was examined on dehydration of bio-ethanol in a self-designed fluidized bed reactor to manufacture ethylene. The effects of dehydration conditions on catalytic behaviors were investigated.The results showed that the V-P/HZSM-5 catalyst demonstrated good activity for bio-ethanol dehydration.Both bio-ethanol conversion and ethylene selectivity were over 90%under the following reaction conditions:a P/V atomic ratio of 7.5,a catahst calcination temperature of 300℃,a reaction temperature of 220℃,a bio-ethanol flow rate of 0.1 mL/min.and a catalyst dosage of 3.0 g.Furthermore,the catalyst exhibited excellent catalytic stability and regeneration capability.

Separation of Sesamin and Sesamolin by a Supercritical Fluid-Simulated Moving Bed

This work shows how the sesamin and sesamolin in sesame seed can be extracted, enriched and purified by the related technologies of supercritical carbon dioxide. Sesame oil is first obtained from the sesame seeds by supercritical carbon dioxide extraction (SFE);lignans in the oil are enriched and precipitated as the top product by supercritical fluid fractionation technology (SFF);the crude lignans are then separated by supercritical fluid-simulated moving bed chromatography (SF-SMB) to obtain pure sesamin and sesamolin. The simulated moving bed is a continuous chromatography;the use of supercritical carbon dioxide as the desorbent simplifies the downstream treatment. By experimental validation, this work also shows that replacing liquid by SF as the desorbent for the SMB automatically creates a gradient operation for the SMB and enlarges the separable range of the operating conditions. Both the design and operation of the SF-SMB are introduced in this paper. The application of SF-SMB to the separation of sesamin and sesamolin provides a novel example for demonstrating the diversity of SF and the potential applications for the production of natural products and the development of botanical drugs.

Hydrodynamics and oxygen transfer in a novel extra-loop fluidized bed bioreactor

In this paper, the characteristics of fluid mixing time in a novel extra-loop fluidized bed were studied. The results showed that the mixing time was shortened with the increase of fluid velocity. All the discrete numbers of the reactor were above 0.2. The serial number n was 2.5 -3.0. It was judged accordingly that the reactor fluid state was continous stirred tank reactor （CSTR） mainly. When the inspiratory capacity increased the mixing time of the reactor was shortened. Thus the air input was beneficial for the fluid mixing. During the three phases mixing process, the mixing time of the reactor could be decreased by the n increase of carrier and air loading together, but the change was not significant. The parameters affecting the reactor fluid state were fluid velocity, inspiratory capacity and carrier. KLa could be increased with the air loading increase, and at the same gas/liquid ratio when the pressure drop was high, KL~ value was increased. The amount of carrier complex influence on KLa. As the carrier loading continued to increase, its value had been dropped but the changes was not significant, and optimization condition was found at above 800 1 000 g carrier loading （pouzzolane） or 600 g PVC. Under gas/liquid ratio of 0.8% -5.2%, KLa was （0.62-1.37）×10^-2· s^-1.

库区浮泥层纵向流速垂线分布特性研究

水库浮泥是存在于水库底部的一层高含沙水体,流动性较强,直接影响水库淤积形态和水库排沙,研究其运动规律对水库减淤优化调度具有重要意义。根据三峡库区实测泥沙矿物组成和级配资料,配置沙样进行流变试验,以幂律流变模型描述浮泥的本构关系。构建了浮泥运动的速度分布理论模型,通过水槽试验对模型进行了验证,计算结果与试验结果吻合较好。结果表明,浮泥运动速度随浮泥厚度、上层水流流速、床面坡度增大而增大,随浮泥密度增大而减少。沿水深方向浮泥纵向流速分布始终呈抛物线型,表层的浮泥流速要远大于底层浮泥,浮泥纵向流速沿垂向方向不断减少,最底部的浮泥几乎处于静止状态。

Geldart C类脱硫灰颗粒在环流耦合提升管内稳定流动特性

我国CO_(2)的排放中70%来自工业领域,故工业过程的碳捕集对实现“双碳目标”十分关键。工业烟气中往往含有的硫氧化物会腐蚀设备并使后续脱碳等过程使用的催化剂中毒。因此,工业烟气的深度脱硫技术对后续的CO_(2)捕集或提纯过程至关重要。循环流化床半干法烟气脱硫因具有脱硫效率高、无污染、停留时间可控等优点受到广泛关注。循环流化床脱硫工艺中作为脱硫剂的脱硫灰颗粒为典型Geldart C类颗粒。由于C类颗粒的强黏附性,其在循环流化床操作中容易结块,从而影响装置稳定运行。为了强化脱硫灰颗粒在循环流化床内的流动稳定性,提出了环流强化的耦合提升管反应器的概念,并自行设计搭建了一套导流筒内径100 mm、高度300 mm,外筒内径160 mm、高度760 mm,输送段内径75 mm、总高度12.6 m的环流耦合提升管。在U_(g)=4 m/s、G_(s)=45 kg/(m^(2)·s),U_(g)=7 m/s、G_(s)=25 kg/(m^(2)·s)的操作条件下,考察了环流段的压力分布、标准差以及功率谱密度。当环隙区气速为0.4 m/s时,环流流动能够实现稳定、连续的密相环流流动。在C类颗粒形成稳定流动基础上,讨论了环流耦合提升管内的流动特性分布规律,包括固含率和颗粒速度。实验发现,环流流动的设计可以强化C类颗粒的流动特性,大幅提高耦合反应器内C类颗粒脱硫灰固含率,并实现了C类颗粒循环流态化装置的稳定运行。同时,这些研究结果可以为C类颗粒新型循环流态化反应器设计提供参考。

列车动载-水力耦合作用下铁路隧道道床隆起机理多尺度模拟与整治对策研究

某高原铁路隧道穿越富水燕山期闪长岩断层带段引发道床出现隆起,对轨道平顺性影响极大。为揭示列车动载-水力耦合作用下铁路隧道道床隆起的宏-细观驱动机制,在考虑隧底结构可能面临的列车动载-水力耦合条件下,提出1种多尺度数值分析方法。结果表明:在6 s的列车动载和地下水耦合作用下,隧底虚渣孔隙率由0.4逐渐增大至0.7,地下水水头高度由50 m升高至100 m,隧底孔隙水压力增加141%,隆起位移增加212%;虚渣孔隙率保持不变时,隧底孔隙水压力增长率与水头高度的增长率保持相同,但虚渣孔隙率增大也会导致隧底孔隙水压力升高,加剧隆起病害;采取“钻孔泄压、注浆固结”整治措施后,隧底孔隙水压力峰值降低79.7%,隆起位移峰值降低至0.08 mm,隆起病害得到显著改善。多尺度数值分析方法可为类似病害整治研究提供参考。

差速流化床及差速循环流化床锅炉

介绍差速流化床的历史背景、工作原理以及低速床内埋管防磨效果和与差速循环流化床相匹配的带加速段卧式旋风分离器结构及其应用。综述了江联重工集团股份有限公司35~220 t/h差速流化床的研发成果,以及哈尔滨工业大学在10~130 t/h差速循环流化床研发方面取得的业绩。比较了常规循环流化床与差速循环流化床的优缺点,在燃烧低热值燃料时差速循环流化床比常规循环流化床具有显著的优越性。

氦冷固态包层氚增殖球床气体和粉末流动特性的数值研究

基于计算流体力学和离散元耦合分析,研究了氦冷固态增殖包层球床中吹扫氦气的速度分布和破碎的正硅酸锂粉末速度随时间的变化及粉末数量随氦气入口流速变化。模拟结果表明,在吹扫氦气流动方向上,用入口流速归一化的氦气速度分布与入口流速无关,在靠近球床边缘速度变化较大,在球床中部速度变化较小;用入口流速归一化的粉末平均速度与入口流速关系不大,会随吹扫时间逐渐趋于稳定;对小粒径粉末,吹扫气体流速越大,越容易被吹出球床,对大粒径粉末,因其本身体积过大,易在球床中形成堵塞。

非球形湿颗粒导向管喷动流化床流动特性

实际工业生产中颗粒多为非球形颗粒,对颗粒形状效应和液相作用机制的研究不足,是导向管喷动流化床在颗粒涂层改性、包膜等工业应用的关键限制因素。选取粒径、密度相似的球形和圆柱形非球形颗粒为实验物料,对比两种颗粒在不同气速和雾滴引入量下的压力脉动信号频谱分析、信息熵分析,并结合床内气固流动对流型进行划分,绘制非球形湿颗粒流动相图,进而探究喷动流化过程中颗粒形状效应及液相作用机制。相比于球形颗粒,粒径、密度相似的非球形颗粒有较小的最小喷动速度,在喷动过程中有两个及以上较低的主频峰且信息熵较大,显示出非球形颗粒在系统内较高的混乱程度,颗粒之间摩擦、碰撞等降低了导向管内颗粒的固体循环速率。液体的引入增大了环形区颗粒间液桥力,使最小流化速度变大,但液体挥发引起喷动气量增大,使最小喷动速度与最小喷动流化速度减小。在喷动流化流型下引入液体,球形颗粒导向管两端压降ΔpDT的脉动主频降低,而非球形颗粒ΔpDT的主频升高。而且非球形颗粒黏附液体后频谱分析结果显示幅值较大的单一主频峰,表明非球形湿颗粒压力脉动规律性的增强。

低负荷下CFB锅炉二次风优化对NO_(x)排放影响的数值模拟

为控制循环流化床(circulating fluidized bed,CFB)锅炉低负荷下NO_(x)的原始排放,以某350 MW超临界CFB锅炉为研究对象,基于计算颗粒流体力学(computational particle fluid dynamics,CPFD)方法对40%负荷下燃烧过程进行数值模拟。分析了不同二次风角度、新增二次风量对NO_(x)排放的影响。结果表明:随着射流角度的减小,炉膛出口NO浓度逐渐降低,CO浓度无明显增加。部分二次风上移后炉膛密相区氧浓度降低,不完全燃烧增加,还原性氛围增强,抑制了NO的生成。当新增风量从10%增加到30%时,NO排放浓度降低了17.2%。但随着比例的进一步提高,炉膛密相区的缺氧环境造成燃烧效率下降,温度大幅降低。因此,在不影响燃烧的前提下可以通过提高新增二次风比例来降低NO的原始排放浓度。

标准椭圆封头式液体再分布器的设计与优化

【目的】液体再分布器大都针对气液固共存体系优化设计,但在盐湖卤水吸附提锂工艺中,吸附塔属于液固体系,有必要研究开发新型液体再分布器与此特殊工况适配。【方法】提出了一种新型标准椭圆封头式液体再分布器,利用椭圆曲面实现集流,利用中心圆孔与环缝组合结构实现中心区域液体再均布。【结果】计算流体力学分析结果表明,在椭球中心沿直径向外100mm、200mm、290mm位置排布尺寸为7mm的3条环缝,液体均布效果最佳。【结论】相比现有液体再分布器完全截断壁流的结构方案,仅减小壁流的通流面积,利用椭球曲面将其导引至主流区外侧,可以解决因壁面粘性造成的近壁区域液体流量远低于中心的问题,实现液体充分均布。

固定床管式反应器内催化剂颗粒堆积与反应模拟

采用数值模拟方法结合反应动力学,针对乙烯环氧化生产环氧乙烷的反应,考察了直径40.0mm的反应管中填充不同宏观尺寸的单孔或七孔催化剂颗粒时,反应器床层平均空隙率、堆密度以及单位床层高度压降、乙烯转化率、环氧乙烷选择性等参数的变化规律。模拟结果表明,对于七孔催化剂颗粒,随着催化剂外径的增加,床层平均空隙率大体呈现减小的趋势,这与单孔催化剂颗粒的变化趋势类似;而床层堆密度、乙烯转化率、环氧乙烷选择性均大体呈现增加的趋势,与单孔催化剂颗粒的变化趋势相反。