Characteristics of high-sulfate wastewater treatment by two-phase anaerobic digestion process with Jet-loop anaerobic fluidized bed

A new anaerobic reactor, Jet-loop anaerobic fluidized bed （JLAFB）, was designed for treating high-sulfate wastewater. The treatment characteristics, including the effect of influent COD/SO42 ratio and alkalinity and sulfide inhibition in reactors, were discussed for a JLAFB and a general anaerobic fiuidized bed （AFB） reactor used as sulfate-reducing phase and methane-producing phase, respectively, in two-phase anaerobic digestion process. The formation of granules in the two reactors was also examined. The results indicated that COD and sulfate removal had different demand of influent COD/SO4^2- ratios. When total COD removal was up to 85%, the ratio was only required up to 1.2, whereas, total sulfate removal up to 95% required it exceeding 3.0. The alkalinity in the two reactors increased linearly with the growth of influent alkalinity. Moreover, the change of influent alkalinity had no significant effect on pH and volatile fatty acids （VFA） in the two reactors. Influent alkalinity kept at 400-500 mg/L could meet the requirement of the treating process. The JLAFB reactor had great advantage in avoiding sulfide and free-H2S accumulation and toxicity inhibition on microorganisms. When sulfate loading rate was up to 8. 1 kg/（m^3.d）, the sulfide and free-H2S concentrations in JLAFB reactor were 58.6 and 49.7 mg/L, respectively. Furthermore, the granules, with offwhite color, ellipse shape and diameters of 1.0-3.0 mm, could be developed in JLAFB reactor. In granules, different groups of bacteria were distributed in different layers, and some inorganic metal compounds such as Fe, Ca, Mg etc. were found.

Start-up and Performance of a Novel Reactor----Jet Biogas Inter-loop Anaerobic Fluidized Bed

A novel anaerobic reactor, jet biogas inter-loop anaerobic fluidized bed （JBILAFB）, was designed and constructed. The start-up and performance of the reactor was investigated in the Process. of .artificial glucose wastewater treatment. With the wastewater recycle ratio of 2.5 ： 1, the recycled wastewater with biogas could mix sludge and wastewater in the JBILAFB reactor completely. The start-up of the JBILAFB reactor could be completed in less than 70 d through maintenance of hydraulic retention time （HR^I＂） and stepwise increase of feed total organic carbon （TOC） concentration. After the start-up, with the volumetric TOC loadings of 14.3 kg·m ^-3·d^-1, the TOC removal ratio, the effluent pH, and the volatile fatty acids （VFA）/alkalinity of the JBILAFB reactor were more than 80%, close to 7.0 and less than 0.4, respectively. Moreover, CH4 was produced at more than 70% of the theoretical value, The reactor exhibited high stability under the condition of high volumetric TOC loading. Sludge granules in the JBILAFB reactor were developed during the start-up and their sizes were enlarged with the stepwise increase of volumetric TOC loadings from 0.8 kg.m^-3.d ^-1 to 14.3 kg.m^-3.d^-1. Granules, an offwhite color and a similar spherical shape, were mainly comprised of global-like bacteria. These had good methanogenic activity and settleability, which were formed probably through adhesion of the bacteria. Some inorganic metal compounds such as Fe, Ca, Mg, Al, etc. were advantageous to the formation of the granules.

Cooling of Granules in Vibrating, Suspended Bed: Engineering Simulation

Here we suggest an algorithm for calculation of the process parameters and design of a vertical cooler with inclined, gas-permeable blades and with a vibrating, suspended layer of granules on them (Vibrating Fluidized Bed—VFB). The algorithm is based on the use of the equations of heat and material balance, taking into account the influx of moisture into the layer with cold air and dust—as a carryover. Mode entrainment of dust particles and moisture from the VFB is described by using empirical formulas and Π-theorem. To calculate the cooling time of granules a model of the dynamics of a variable mass VFB was built, which linked the geometrical and physical process parameters to a single dependency. An example showed that mass flow of granules of 248 kg/h and a volume flow of air of 646 m3/h with temperature of 30℃ to cool the zeolite granules from 110℃ to 42℃ for 49 s required a vertical apparatus of rectangular shape with four chambers and with volume of 0.2 m3. A comparative analysis of technological parameters of the projected cooler with the parameters of typical industrial apparatuses showed that for all indicators: the cooling time of granules, the flow rate of gas (air) and the heat flow, a 4-chambered, vertical apparatus of rectangular shape with VFB was the most effective.

Moisture sorption and diffusion determination of Chinese herbal granules:Moisture-resistant effects of fluidized bed granulation with dextrin

Objective: To investigate the effects of fluidized bed granulation with dextrin on moisture sorption and diffusion of Zexie Decoction granules.Methods: The particle characterization was studied by the particle size, scanning electron microscopy(SEM), differential scanning calorimetry(DSC), and Fourier transform infrared(FTIR). The moisture sorption isotherm, equilibrium moisture content(EMC), and moisture diffusion coefficients were determined by using the saturated salt solution method.Results: The particle size increased from 6.04 μm(powder) to 1201.47 μm(granule). The glass transition temperature of dextrin, Zexie Decoction powder, and granule was 107.13 °C, 94.82 °C, and 126.25 °C. As the increase of temperature, the initial rate of moisture sorption become higher. Furthermore, the initial rate of moisture sorption of Zexie Decoction granules was lower than those of powders and dextrin. The EMC and moisture diffusion coefficients were reduced significantly after granulation(P < 0.01). Critical relative humidity and diffusion activation energy of granules were higher than powders.Conclusion: Results suggested that fluidized bed granulation with dextrin could reduce the hygroscopicity of the Zexie Decoction extract powders and inhibited moisture diffusion, which is mainly related to the microstructure reorganization by fluidized bed granulation and anti-plasticizing effects of dextrin.

Influence of zone formation on stability of continuous fluidized bed layering granulation with external product classification

Continuous fluidized bed layering granulation with external product classification and a sieve-mill cycle can show instability in the form of self-sustained nonlinear oscillations of the particle size distribution. In the present study, the stability and bifurcation analysis of this process is presented. The underlying process models explicitly account for compartmentalization of the fluidized bed into a granulation and a drying zone, which is an important feature of many technical processes. Implications for plant operations are discussed with the help of stability diagrams as a function of zone size, residence time within different zones, the addition of external seeds and particular properties of the sieve-mill cycle.

Heat and mass transfer study in fluidized bed granulation-Prediction of entry length

Fluidized bed granulation is a process by which granules or coated particles are produced in a single piece of equipment by spraying a hinder as solution, suspension, or melt on the fluidized powder bed. Heat and mass transfer correlation useful for designing a granulator has been derived based on the equivalence of evaporation rate of the liquid to the heat transferred from hot gas to particles： （m/A）Dp^2λ/Lmf（1-εmf）（Tg-Tl）Kg=hDp/Kg.This equation is applied to data on granulation experiments by different workers to calculate Reynolds number and Nusselt number to obtain a relation between heat and mass transfer from gas to particles during granulation on a logarithmic scale from which the following empirical relation is obtained： Nu=0.0205Re^1.3876 which is comparable to Kothari＇s correlation Nu=0.03Re^1.3.By using the heat and mass transfer correlation obtained, the entry length, that is the length of granulator up to which effective heat transfer from gas to bed particles takes place, is estimated, which is also validated with experimental study. The correct estimation of entry length is useful in optimal design of a granulator.

导流板对喷雾流化床内颗粒生长过程影响的模拟

喷雾流化床内湿法造粒过程已广泛应用于能源、制药、食品和化工等各种工业领域,然而流化床中的颗粒生长过程涉及到复杂的气-液-固三相相互作用,进而难以实现造粒过程的精确控制。基于离散单元模型,通过添加液桥力模型和颗粒生长模型开展喷雾流化床内导流板结构对床内颗粒流动和生长特性影响的研究,分析颗粒流化状态对颗粒生长均匀性的影响。研究发现,在本文工况内,随着床内导流板长度的增加、导流板间距和高度的降低,颗粒流化状态得到改善,颗粒生长区域进一步扩大,颗粒循环时间增加,单次颗粒涂层增长量降低,颗粒生长得更均匀。

流化床造粒技术在尿素生产中的应用分析

以流化床造粒技术原理及其在尿素生产中的应用优势为切入点,在此基础上分析其应用的具体方法,就工作系统建设、流程管理、参数控制以及生产跟踪等工作进行论述,展望了流化床造粒技术在尿素生产中的应用趋势,包括智能化、标准化等,以系统呈现该技术的特点,为尿素生产工作提供参考。

三种常见制粒技术对中药制剂内在质量的影响及生产过程控制要点

比较分析湿法挤出制粒、干法制粒、流化床制粒3种不同制粒方式对中药制剂的内在质量的影响,根据其制粒方式浅论生产过程质量控制要点,为中药生产企业制粒方式的选择提供参考。

工业水质软化处理工艺中CO_(2)的应用试验研究

全球CO_(2)年排放量约为340亿t,工业领域的节能降碳已经成为“双碳”背景下的工业企业发展趋势。将CO_(2)固定与化学结晶造粒流化床水处理系统相结合,把CO_(2)作为软化药剂与NaOH共同用于高硬度水质的软化处理。考察药剂投加量及药剂投加浓度比、系统上升流速变化并与现有的处理方法进行对比。结果表明,该方法可以获得良好的软化效果,其中Ca^(2+)去除率最高可达到89%,总硬度去除率最高可达到85%。NaOH投加量对软化效率起主要影响作用,因此可以通过控制CO_(2)投加量灵活控制软化出水pH和碳酸盐浓度,免去了软化出水后续的pH调节工艺,同时提升了水质稳定性。上升流速变化试验结果表明,上升流速为110 m/h的条件下该方法仍可获得良好的软化效果,具有良好的抗冲击负荷能力。与目前所使用的“双碱法”(NaOH和Na_(2)CO_(3)作为软化药剂)相比,该方法碱性药剂投加总量低,吨水处理药剂成本低,具有良好的经济效益和生态效益。将CO_(2)作为软化剂应用于化学结晶造粒流化床系统可作为一种CO_(2)固定的新技术,具有较大的推广应用潜力。

结晶造粒流化床技术在浓盐水软化除硬处理中的设计应用

石油化工企业脱盐水用水量大,出于节水的考虑,需要将浓水进行回收处理,为了防止回收处理的浓缩过程结垢,保证浓水反渗透正常运行,在一项石化企业的脱盐水处理项目上,采用结晶造粒流化床技术对反渗透浓盐水进行化学除硬预处理,处理后的浓盐水硬度约为200 mg/L,收到了良好的应用效果。

质量源于设计在流化床制粒研究中的应用

应用“质量源于设计”(QbD)理念,通过工艺变量初始风险评估,确定对关键质量属性(CQA)具有潜在影响的高风险工艺变量,设计实验并根据结果制定科学合理的生产操作范围和控制策略。在工艺开发过程中,研究了环境温度湿度、喷液速度、进风温度对流化床制粒得到的颗粒性质的影响。结果表明环境湿度变大,进风风量含水量变大,制得的颗粒变大;喷液速度由40.0 g/min降低至25.0 g/min,制得的颗粒80目以下颗粒由15.0%增加至49.8%,颗粒变小;喷液速度25.0 g/min,进风温度60~70℃,进风风量80~100 m3/h,制得的颗粒大小无显著变化,说明进风风量对颗粒大小无显著影响。

采用HPLC法测定葡糖醛酸筛选葡醛内酯片制备方法

目的:制备葡醛内酯片,采用HPLC(高效液相色谱法)法测定葡醛内酯片中葡糖醛酸的含量,筛选制备方法,并为葡醛内酯片的质量控制提供参考。方法:以片芯收率为指标,采用正交分析确定基本处方,并运用不同的制粒方法制备葡醛内酯片(50mg规格);采用HPLC(高效液相色谱法)法分析测定不同制法的葡醛内酯片中葡糖醛酸含量,筛选出最优的制备方法。结果:采用HPLC法葡糖醛酸与碱降解峰之间分离度均大于1.5,呈良好线性关系,回收率为90%~108%,精密度,重复性、专属性良好,同时该方法需临用前制备,2~8℃冰箱保存下20min内稳定。以乳糖占比30%,低取代羟丙纤维素占比4%,葡醛内酯粒径为40目作为基本处方,按同一处方不同制备方法自制制剂,分析葡糖醛酸含量结果表明干法制粒与流化床制粒下葡醛内酯片的葡糖醛酸含量较低。结论:HPLC(高效液相色谱法)方法灵敏,专属性好,可用于葡醛内酯片中葡糖醛酸的测定;葡醛内酯片干法制粒与流化床制粒工艺更好。

电厂湿式电除尘冲洗废水处理新工艺

文章介绍了一种结晶造粒流化床与扭转式纤维过滤器结合的新工艺,并将其与反渗透法联合处理电厂湿式电除尘冲洗废水,提供了一种新型解决方案。分析了湿式电除尘器冲洗废水水质特征,采用的新工艺自用水率低,出水水质好,悬浮物去除率95%以上,总硬度去除率62%左右;由于水力负荷较高(流化床水力负荷可达到12 m^(3)/m^(2)·h~15 m^(3)/m^(2)·h,扭转式纤维过滤器约60 m^(3)/m^(2)·h~100 m^(3)/m^(2)·h),设备结构紧凑,占地可节约75%左右;整个工艺实现了无人值守全自动化运行。

替比培南匹酯颗粒的制备及体内外评价

目的制备替比培南匹酯颗粒并测定其体外溶出曲线,考察其在Beagle犬体内的药动学特征。方法先用湿法制粒制备含药内核颗粒,再用流化床进行底喷包衣,考察不同包衣层(隔离层、掩味层、矫味层)增重对产品体外溶出的影响,确定各层最佳增重;采用正交实验法确定掩味层中各包衣组分(乙基纤维素水分散体、尤特奇NE30、羟丙基甲基纤维素E6)的最佳比例;以替比培南匹酯颗粒为参比制剂,进行体外溶出行为和Beagle犬体内药动学对比实验。结果自制制剂和参比制剂体外溶出行为相似,在犬体内的AUC_(0~∞)、t_(max)和C_(max)分别为(4678±652)和(4215±897)h·μg·L^(-1)、(1.5±0.55)和(1.17±0.41)h、(1838±179)和(1915±402)μg·L^(-1),差异均无统计学意义(P>0.05)。以AUC_(0~t)计算得自制制剂的相对生物利用度为(118.67±14.57)%。结论本文研究出的替比培南匹酯颗粒处方工艺可行,质量稳定,与参比制剂相似,可为其仿制研究提供依据。

流化床一步制粒法的工艺优化

采用流化床一步制粒法制备工业压片颗粒,讨论了流化床设备工艺参数（进风风量、进风温度,喷雾速率和喷雾压力）对颗粒形成的（粒径分布和休止角）影响。结果表明,最佳实验条件为风机频率23~35 Hz,进风温度60℃,喷雾速率10 mL/min,喷雾压力1.5 MPa时,所得颗粒粒径分布最优,流动性最好。

流化床喷雾造粒技术进展

本文介绍了流化床喷雾造粒技术,包括造粒机理、操作方式、影响因素等。流化床喷雾造粒是将溶液、悬浮液或熔融液喷雾到已经干燥或不完全干燥颗粒的流化床床层内,在同一设备内一步完成蒸发、结晶、干燥或化学反应的造粒过程。流化床造粒操作对颗粒的尺寸、形状要求不高,所得到的产品无结块、具有良好的流动性能。与其他传统的造粒方法相比,流化床造粒具有工艺流程简单、设备装置紧凑、投资省、生产强度大等优点,越来越引起人们的关注。

负载型TiO_2固定相光催化氧化剂固定化技术研究

以耐火砖颗粒为载体 ,用浸涂法制备了负载型TiO2 光催化氧化剂 ,并设计了一种二相流化床光催化反应器。考察了固相催化剂制备过程中粘结剂的量、载体粒度及催化剂的表面处理方式等因素对催化剂的活性影响。结果表明 ,在流化床光催化反应器中 ,利用该方法制备的负载型TiO2 光催化氧化剂 ,对染料 4BS溶液的降解脱色反应具有很好的光催化活性及光催化效果的稳定性 ,为光催化技术的实际应用提供了有意义的尝试。

流化床包衣颗粒释放特性的影响因素

在一间歇锥形流化床中,以尿素颗粒(D=0.8 mm)为晶核,明胶为包膜物质,研究了流化气速、床层温度、喷嘴雾化空气压、料液质量浓度对包衣颗粒释放特性的影响。结果表明,在实验范围内,得到的包衣颗粒产品具有相似的溶解释放特性曲线。床层温度对释放速度的影响显著,流化气速、料液质量浓度对释放速度也有较大影响,而且均是非单调的。但雾化空气压与释放特性之间存在反向相关性。

流化床制粒影响因素的探讨

讨论了流化床制粒的影响因素和生产中易出现的问题。