转轮除湿器的数学模型及性能研究

建立了转轮除湿器的传热传质数学模型,利用有限差分法对方程组进行离散求解,并编制程序进行模拟,模拟结果与实验数据吻合较好,得到了稳态运行一个周期内空气温湿度和吸附剂温度、吸附率的变化规律及转轮除湿能力的影响因素.     

两种不同形式太阳能吸附床制冷性能比较

应用集总参数法建立太阳能集热吸附床能量守恒的数学模型,对以活性炭-甲醇为工质对的真空集热管吸附床和平板式集热吸附床进行模拟分析比较,分析吸附床的逐时吸附速率,得到集热床的温度和时间的函数关系,求解函数并绘制出吸附床温度随时间变化的曲线图。对太阳能吸附式制冷系统进行性能分析,对比分析两种吸附床系统的优缺点,并提出了改进的方向。     

变压吸附技术应用研究进展

变压吸附技术由于具有能耗低、工艺流程简单、操作费用小等优点,广泛用于气体的分离和回收领域。介绍了变压吸附的原理及应用进展,特别是在炼油厂干气提纯回收、煤层气净化回收中的应用前景。提出了目前技术存在的问题和相应的解决措施,针对传统变压吸附剂存在的吸附量较低、气体回收率不高等缺点,阐述了以高表面活性炭为吸附剂的变压吸附在这些领域中的发展潜力。     

变压吸附气体分离技术 四川天一科技股份有限公司

<正>四川天一科技股份有限公司(天科股份,股票代码600378)是国家科技部和中国科学院评审认定的高新技术企业。公司下属的变压吸附分离工程研究所是专业从事变压吸附(简称PSA)气体分离技术的研究、工程技术开发、工程设计、工程承包的机构。公司已建成投产各类变压吸附装置1000多套。天科股份变压吸附提纯氢气装置单套产氢能力已达到     

异养硝化菌的分离及其强化活性污泥脱氮效果

为提高水处理过程中的脱氮率，实现好氧条件下对总氮的去除。通过试验分离出一株异养硝化菌，该菌株为白色革兰氏阴性球状菌。将该菌扩大培养后接种于活性污泥系统并进行了处理模拟废水的试验。结果表明：该菌能在好氧条件下分别代谢氨氮、亚硝酸盐氮、硝酸盐氮，并通过好氧反硝化实现对总氮的去除。用该菌株强化的活性污泥系统对以氨氮、亚硝酸盐氮、硝酸盐氮为惟一氮源的模拟废水进行处理，4h的总氮去除率分别为85％、60％、70％。     

变压吸附气体分离技术 四川天一科技股份有限公司

<正>四川天一科技股份有限公司(天科股份,股票代码600378)是国家科技部和中国科学院评审认定的高新技术企业。公司下属的变压吸附分离工程研究所是专业从事变压吸附(简称PSA)气体分离技术的研究、工程技术开发、工程设计、工程承包的机构。公司已建成投产各类变压吸附装置1000多套。天科股份变压吸附提纯氢气装置单套产氢能力已达到280000m~3/h以上,可满足石化、化工系统国产大型化装置的需求。目前公司的变压吸附技术和装置已在石油化工、化     

HA-A/A-MCO污泥减量工艺的微生物与污泥特性

针对现有污泥减量技术中存在的对氮、磷去除率低的问题,开发了具有脱氮除磷和污泥减量功能的HA-A/A-MCO工艺.对微型动物种群变化及污泥特性进行了分析以揭示其污泥减量化机制.结果显示,曝气池实现了生物相的有效分离以及高等微生物的生长繁殖,利用微生物的逐级捕食作用达到了污泥减量效果.稳定运行时,系统各反应池的微型动物种类及数量呈现明显变化特征:厌氧池、缺氧池与细菌培养池的微生物种类与数量基本相当,以游泳型纤毛虫占绝对优势,几乎没有后生动物;好氧2池以固着类纤毛虫为优势种群,且轮虫和红斑瓢体虫数量渐增;好氧3池以固着类纤毛虫和后生动物(轮虫和红斑瓢体虫)占绝对优势.系统的污泥产率随曝气池生物相的逐渐明显分离与高级别微型动物数量的增加呈下降之势,最终稳定在0.112 gMLSS/gCOD.HA-A/A-MCO系统拥有较低的SOUR是由低有机负荷引起的,而不是由微型动物的捕食所致.     

变压吸附装置非连续生产方式的研究

文章对上海石洞口煤气制气有限公司制气装置上的变压吸附制氮装置吸附剂的性能情况进行了分析,并想通过工艺操作的优化,寻求一套适合非连续生产方式下的变压吸附装置操作方法,以改善吸附装置的工作状态,延长吸附剂使用年限;从而保证煤气质量指标,降低制气成本。     

变压吸附气体分离技术 四川天一科技股份有限公司

<正>四川天一科技股份有限公司(天科股份,股票代码600378)是国家科技部和中国科学院评审认定的高新技术企业。公司下属的变压吸附分离工程研究所是专业从事变压吸附(简称PSA)气体分离技术的研究、工程技术开发、工程设计、工程承包的机构。公司已建成投产各类变压吸附装置1000多套。天科股份变压吸附提纯氢气装置单套产氢能力已达到280000m³/h以     

变压吸附气体分离技术 四川天一科技股份有限公司

<正>四川天一科技股份有限公司(天科股份,股票代码600378)是国家科技部和中国科学院评审认定的高新技术企业。公司下属的变压吸附分离工程研究所是专业从事变压吸附(简称PSA)气体分离技术的研究、工程技术开发、工程设计、工程承包的机构。公司已建成投产各类变压吸附装置1000多套。天科股份变压吸附提纯氢气装置单套产氢能力已达到280000m~3(标)/h以上,可满足石化、化工系统国产大型化装置的需求。目前,公司的变压吸附技术和装置已在石油化工、化工、冶金、环保、食     

天然气制气中优化PSA装置操作

天然气制气工艺中PSA装置的作用是接收来自掺混空气压缩机的压缩空气,通过变压吸附除去压缩空气中部分氧气,生成的富氮气供煤气掺混。PSA装置的运行直接影响到煤气生产稳定和煤气掺混质量,研究一套正确的操作方法,并实施必要的设备改造以保障PSA装置稳定运行。     

Field analysis of PSA O2–ozone production process for water recycling

The use of an oxygen generator based on pressure swing adsorption technology (PSA) has been investigated as an alternative method for supplying oxygen for onsite ozone production. During the investigation period of 1040 h, the oxygen purity from the PSA process fluctuated within a range of 90.5–93 O₂% (v/v). Using the working ratio of 2.8 mol of O₂ to 1 m³ of raw water, the PSA process in series with a corona discharge ozone generator yielded an oxidation–reduction potential of ca. 200 mV and a concentration of 22.8 mg/L dissolved oxygen. The average efficiency of the raw water treatment was as follows: 47% chemical oxygen demand removal, 78% biological oxygen demand removal, 36% sulphide removal and 34% colour removal. The operating cost of the PSA O₂ generation was reduced 3 times compared with the cost of high‐pressure oxygen cylinders.     

Oxygen concentrators for medical gas pipeline systems.

In summary, the concern of the Department is patient safety; the effectiveness and suitability of oxygen PSA plant has been demonstrated. The Department will be including recommendations for the design and operation of PSA plant in the revised addition of HTM 22 and work has commenced on preparing an additional section to cover oxygen concentrators. In the future therefore it will be fitting and proper for the decision on the final choice of plant to be based on its cost effectiveness now that doubts over the suitability of PSA systems have been dispelled.     

Calibration and validation of an ASM3-based steady-state model for activated sludge systems--part II: Prediction of phosphorus removal

An ASM3-based steady-state model which can be used for estimating the average nitrogen-removal, sludge-production and phosphorus-removal rates of different biological phosphorus-removing systems (AAO, UCT, intermittent processes) is developed. It considers the wastewater composition, the oxygen and nitrate input in the anaerobic compartment and the interaction between biological phosphorus removal and denitrification for different operating conditions. The model is calibrated and validated with data from a number of long-term pilot and full-scale experiments for Swiss municipal wastewater. The steady-state model is adequate for a comparison of different BPR process configurations or for a first estimation of the nutrient-removal efficiency. It allows the plant performance and key parameters to be determined very quickly. Excel spreadsheets of the model for different flow schemes are available from the corresponding author.     

Modeling of phosphorus dynamics in aquatic sediments: I--model development

A model is developed to study the phosphorus dynamics in aquatic sediments and to conduct dynamic predictions of phosphorus release across a sediment-water interface. The model focuses on the sediment active layer below the sediment-water interface and is based on primary mechanisms regulating phosphorus behavior in sediments, including effective diffusion, bioturbation mixing and burial processes (transport), organic decomposition, sorption kinetic processes and non-linear partitioning (mobilization). The effects of environmental factors such as dissolved oxygen and temperature are taken into account. The model is solved by numerical integration.The primary difference from models in the literature is that the model directly describes the dynamic behavior of dissolved, particulate exchangeable ortho-phosphorus and organic phosphorus in sediments, and incorporates dynamic sorption and non-linear partitioning processes. These improve model mechanisms and allow regulation of phosphorus flux through the sediment reservoir that acts as both a source and sink of phosphorus.     

富氧空调的可行性探讨

空调环境的氧含量普遍低于20.9%,有必要采取措施补充空调环境消耗的氧气,改善室内空气质量。简要介绍了几种制氧方法,提出将变压吸附制氧或膜分离制氧用于空调环境增氧的思路,并且描述了这两种增氧系统。以某体育场馆为例,对两种增氧系统与传统的增大新风量增氧方式进行了比较,认为前者在设备初投资和运行成本上都具有优势,而且能够满足空调环境的增氧要求。     

A coupled thermal-hydraulic-mechanical application for assessment of slope stability

The stability of a slope is subjected to thermal (T), hydraulic (H), and mechanical (M) loadings and their coupling effects. Modeling the coupled THM processes that occur in the slope is important for reliably assessing and predicting the slope performance and stability. Therefore, a numerical model, which can consider the full coupling among the thermal (temperature variation), hydraulic (pore water pressure), and mechanical (stress and displacement) processes, is developed in this study. The developed model is employed to analyze slope stability, and the simulated results are seen to coincide well with the results obtained by traditional limit equilibrium calculation. A comparison of the results verifies the validity of the developed model for slope stability analyses under THM coupled effects. Furthermore, the capability of the developed THM model for predicting the slope performance is validated through comparisons of three case studies in terms of both laboratory experiments and numerical simulations. A favorable agreement between the modeling results and the compared data confirms the capability of the developed model to accurately describe the behavior of a slope affected by THM coupled processes. The modeling results can also contribute to a better understanding of slope failure induced by the THM couplings.     

How groundwater seepage and transport modelling software can be useful for studying gaseous transport in an unsaturated soil

The aim of this paper is to show how standard hydrogeologic software, usually used to model contaminant transport in groundwater under unsaturated conditions, can also be used to model gas transport in unsaturated porous media. Physical processes involved in the interaction between the atmosphere and the unsaturated soils are considered: transport by diffusion through the air and the groundwater, exchange between the liquid and gas phases and consumption. These physical processes are incorporated into the governing equations of a groundwater numerical code; by considering air, contained in the unsaturated soil, as water in the seepage numerical model, the air effectively becomes fluid within the numerical code. Then, the investigated gas is defined as the contaminant in the transport model, which is transported by -the air for the modeller-, and -water for the numerical code-. The over-riding assumption is that the air profiles and, therefore, water profiles of volume contents remain constant. The approach is illustrated using two examples, which consider the transport of oxygen. The first deals with oxygen distribution through a laboratory-cell diffusion containing reactive mining tailings. The second deals with the oxygen fluxes through the vadose zone, between the atmosphere and an unconfined aquifer's water table. Both examples consider different cases of oxygen consumption.     

Dynamic behavior of ozonation with pollutant in a countercurrent bubble column with oxygen mass transfer

The dynamic behavior of ozonation with pollutants in a countercurrent bubble column is studied for the model establishment. Bubble columns have been widely used for an ozonation system in the plants and laboratories. In addition, a countercurrent bubble column has been commonly recommended than a cocurrent one because it has a higher ozone transfer efficiency. Therefore, the investigation of this paper focuses on the countercurrent bubble column. As an ozonation process starts, the gas mixture of ozone and oxygen is introduced into the bottom of a column, and then transferred into the liquid. The pollutants in the wastewater are eliminated subsequently via oxidation by the dissolved ozone. There certainly exists a temporary and unsteady period before the ozonation system reaches steady state. However, available ozonation models employed to describe ozone and pollutant profiles have commonly been developed for steady state. The treating qualities of wastewater in the early stage of ozonation are usually not predicted, and the time required for the steady-state establishment remains to be determined. Moreover, oxygen mass transfer is usually neglected in previous ozonation models so that the increase of dissolved oxygen is uncertain. These information is desirable for the proper design and operation of ozonation system in a bubble column. Thus, the aim of this study is to model and investigate the dynamic processes of ozonation with pollutants including oxygen mass transfer. The dynamic axial dispersion model proposed is employed to predict the variation of the ozone, pollutant, and oxygen concentrations profiles. The validity of the model was demonstrated by comparing the predicted results with the experimental data. The o-cresol was chosen as the model pollutant. The temporal concentration variations of the residual o-cresol and dissolved oxygen in the effluent liquid, and the off-gas ozone in the free volume were measured accordingly. Furthermore, the variation of the enhancement factor of ozone and the amount of off-gas were predicted. Note that it usually needs 2-5 hydraulic retention times to approach steady state under the conditions of this study. Further, the effects of dimensionless system parameters on the performance of the ozonation processes are examined. As a result, the proposed dynamic model of ozonation with pollutants is useful for proper prediction of the variables of an ozonation system in a countercurrent bubble column.