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.

Three-dimensional Simulation of Gas/Solid Flow in Spout-fluid Beds with Kinetic Theory of Granular Flow

A three-dimensional Eulerian multiphase model, with closure law according to the kinetic theory of granular flow, was used to study the gas/solid flow behaviors in spout-fluid beds. The influences of the coefficient of restitution due to non-ideal particle collisions on the simulated results were tested. It is demonstrated that the simulated result is strongly affected by the coefficient of restitution. Comparison of simulations with experiments in a small spout-fluid bed showed that an appropriate coefficient of restitution of 0.93 was necessary to simulate the flow characteristics in an underdesigned large size of spout-fluid bed coal gasifier with diameter of 1m and height of 6m. The internal jet and gas/solid flow patterns at different operating conditions were obtained. The simulations show that an optimal gas/solid flow pattern for coal gasification is found when the spouting gas flow rate is equal to the fluidizing gas flow rate and the total of them is two and a half times the minimum fluidizing gas flow rate. Be-sides, the radial distributions of particle velocity and gas velocity show similar tendencies; the radial distributions of particle phase pressure due to particle collisions and the particle pseudo-temperature corresponding to the macro-scopic kinetic energy of the random particle motion also show similar tendencies. These indicate that both gas drag force and particle collisions dominate the movement of particles.

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.

Characterization and evaluation in vivo of baicalin-nanocrystals prepared by an ultrasonic-homogenization-fluid bed drying method

AIM: To improve the absorption and bioavailability of baicalin using a nanocrystal(or nanosuspension) drug delivery system. METHODS: A tandem, ultrasonic-homogenization-fluid bed drying technology was applied to prepare baicalin-nanocrystal dried powders, and the physicochemical properties of baicalin-nanocrystals were characterized by scanning electron microscopy, photon correlation spectroscopy, powder X-ray diffraction, physical stability, and solubility experiments. Furthermore, in situ intestine single-pass perfusion experiments and pharmacokinetics in rats were performed to make a comparison between the microcrystals of baicalin and pure baicalin in their absorption properties and bioavailability in vivo. RESULTS: The mean particle size of baicalin-nanocrystals was 236 nm, with a polydispersity index of 0.173, and a zeta potential value of-34.8 mV, which provided a guarantee for the stability of the reconstituted nanosuspension. X-Ray diffraction results indicated that the crystallinity of baicalin was decreased through the ultrasonic-homogenization process. Physical stability experiments showed that the prepared baicalin-nanocrystals were sufficiently stable. It was shown that the solubility of baicalin in the form of nanocrystals, at 495 μg?mL-1, was much higher than the baicalin-microcrystals and the physical mixture(135 and 86.4 μg?mL-1, respectively). In situ intestine perfusion experiments demonstrated a clear advantage in the dissolution and absorption characteristics for baicalin-nanocrystals compared to the other formulations. In addition, after oral administration to rats, the particle size decrease from the micron to nanometer range exhibited much higher in vivo bioavailability(with the AUC(0-t) value of 206.96 ± 21.23 and 127.95 ± 14.41 mg?L-1·h-1, respectively). CONCLUSION: The nanocrystal drug delivery system using an ultrasonic-homogenization-fluid bed drying process is able to improve the absorption and in vivo bioavailability of baicalin, compared with pure baicalin coarse powder and micronized baicalin.

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.

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.

Pilot Scale Test to Treat High Concentration Gasification Wastewater Using Catalytic Oxidation and Aerobic Biological Fluid-Bed Combination Process

The gasification wastewater is a kind of typical organic industrial wastewater with high chemical oxygen demand (COD) and ammonia nitrogen, which could not be completely degraded by the traditional physical, chemical and biological method. So it is very important to find an effective treatment process. A combination process of catalytic oxidation with noble metal catalysts and aerobic biological fluid-bed packed with the new ultrastructure biological carriers, which was developed by ourselves, was investigated to treat the gasification wastewater. The pilot scale test with 0.5 m3/h influent flow was carried out to investigate the performance of this new combination process. The results showed that the effluent COD was 84.02 mg/L, ammonia nitrogen was 14.15 mg/L, and total phenol was 0.20 mg/L, which could completely meet the Grade Ⅰof Wastewater Discharge Standard (GB8978-1996), when the influent average COD was 5564 mg/L, ammonia nitrogen was 237 mg/L, and total phenol was 1100 mg/L. The two catalytic reactors could evidently improve the wastewater biodegradability, and the value of BOD5/COD (B/C) increased from 0.23 to 0.413 in the one-stage catalytic reactor and from 0.273 to 0.421 in two-stage catalytic reactor. The further experiment results showed that the effluent quality of this new combination process could still meet the discharge standard, when the COD loading was 8.65 kg / (m3·d). Most of aromatic and heterocyclic compounds were degraded effectively in this combination process.

CFD-DEM simulation of fluid-solid flow of a tapered column separation bed

Research on recycling waste Printed Circuit Boards(PCB) is at the forefront of preventing environmental pollution and finding ways to recycle resources.The Tapered Column Separation Bed(TCSB) is invented aiming at disposing the problem that fine particles of waste printed circuit boards cannot be separated efficiently so as to obtain further insight about the underlying mechanisms and demonstrate the separation feasibility in the tapered column separation bed.In this work,a Computational Fluid Dynamics(CFD) coupled with Discrete Element Method(DEM) model for two-phase flow has been extended to simulate the fluid-solid flow in the tapered column separation bed.Its validity is demonstrated by its successful capturing the key features of particles' flow pattern,velocity,the pressure distribution,the axial position with time and axial force for particles with different densities.Simulation results show that the plastic particles and resin particles become overflow,while copper particles,iron particles and aluminum particles successively become underflow,with a discharge water flow rate of 1 m^3/h,an obliquity of 30°.The simulated results agree reasonably well with the experimental observation.Using this equipment to separate waste PCBs is feasible,theoretically.

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。

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。