Hydrogen production by partial oxidation of methane: Modeling and simulation

A one-dimensional non-isothermal model for oxygen permeable membrane reactor has been developed to simulate the partial oxidation of methane to produce hydrogen. The performance of two fixed bed reactors (FBRs) viz. one with pure O₂ in feed (FBR1), other with air in feed (FBR2), and a membrane reactor (MR) having air in non-reaction side have been studied at various feed conditions and inlet temperatures in order to investigate the effect of these parameters on conversion of methane and yield of hydrogen. The fixed bed reactor with pure O₂ in feed has been found to provide better performance as compared to fixed bed reactor with air and membrane reactor.     

聚丙烯反应器出料口块料形成的原因分析及对策

针对引进的Spheripol工艺反应系统中多次出现块料,造成系统停车的原因进行了分析,揭示了出现块料的可能原因以及解决的方法,为装置的稳定运行打下了基础。     

Integration of photocatalysis and membrane distillation for removal of mono- and poly-azo dyes from water

The paper reports investigations on the application of anatase-phase TiO₂ for the removal of azo dyes in a hybrid system coupling photocatalysis with direct contact membrane distillation (DCMD, MD). The process was conducted in a laboratory-scale installation equipped with a PP capillary module. The influence of reaction temperature and initial concentration of azo dyes on the effectiveness of their photodegradation was especially investigated. Two mono-azo dyes: Acid Red 18 (AR18) and Acid Yellow 36 (AY36) and one poly-azo dye, Direct Green 99 (DG99) were applied as model compounds. The increase of the reaction temperature from 313 to 333 K resulted in an improvement of the efficiency of photodecomposition of the dyes, as was found on the basis of changes of their masses in the feed solution. The comparison of the results obtained during photocatalysis alone and hybrid photocatalysis-MD process revealed that the reduction of feed volume in MD did not affect the photodegradation rate of the azo dyes. An improvement of the effectiveness of the degradation of dyes was obtained by an application of solutions with lower initial concentration (10 instead of 30 mg/dm³). Regardless of the process parameters applied, the product (distillate) was almost pure water with conductivity lower than 0.3 mS/m and pH above 5.2.     

An appraisal of tree sulphur content as a long term air pollution gauge

Plant sulphur content of tree annual ring groups is used as an air pollution gauge in the vicinity of the Port Talbot (South Wales) steel works. The results indicate, with regards sulphur dioxide pollution, a recent improvement in air quality. Dendrochronological measurements also indicate this general trend.     

研究堆放射性湿废物处理系统湿废物桶内处理工艺设计方案研究

通过对核电站放射性湿废物处理系统湿废物桶内处理工艺参数的比较，介绍了研究堆放射性湿废物处理系统废物桶内处理工艺设计方案以及在湿废物桶内处理工艺设计中遇到的重点、难点，并对这些重点、难点的解决方案进行了探讨。该方案在保证工作人员人身安全的前提下，更能适合研究堆的湿度物处理。     

Predicting the contractual cost of unplanned shutdowns of power stations: An accelerator-driven subcritical reactor case study

This paper discusses analysis of the acute contractual cost of a failure to supply electricity from the perspective of power station owners. It presents a model for analysing the financial cost to an electricity supplier in the context of a national grid when a power station unexpectedly instantaneously shuts down. The model probabilistically samples historical market data and includes analysis of the impact on the system buy price of historic unplanned generator shutdowns. A case study is presented for a potential future nuclear power station concept, the Accelerator-Driven Subcritical Reactor (ADSR), in the UK market. The reliability of ADSRs is a key issue in their future development. The model is used to identify an upper limit on the amount an operator should be willing to pay for reliability improvements that mitigate unplanned shutdowns. The case study results are presented in a form that allows the reader to scale the cost of accelerator system failures for any capacity factor and coefficient of reliability, for a range of discount rates.     

A continuous ultrasound‐assisted packed‐bed bioreactor for the lipase‐catalyzed synthesis of caffeic acid phenethyl ester

BACKGROUND: The focus of this paper is the ultrasound‐assisted synthesis of caffeic acid phenethyl ester (CAPE) from caffeic acid and phenyl ethanol in a continuous packed‐bed bioreactor. Immobilized Novozym^® 435 (from Candida antarctica) is used as the catalyst. A three‐level–three‐factor Box–Behnken design and a response surface methodology (RSM) are employed to evaluate the effects of temperature, flow rate, and ultrasonic power on the percentage molar conversion of CAPE. RESULTS: Based on ridge max analysis, it is concluded that the optimum condition for synthesis is reaction temperature 72.66 °C, flow rate 0.046 mL min^?1, and ultrasonic power 1.64 W cm^?2. The expected molar conversion value is 97.84%. An experiment performed under these optimal conditions resulted in a molar conversion of 92.11 ± 0.75%. The enzyme in the bioreactor was found to be stable for at least 6 days. CONCLUSIONS: The lipase‐catalyzed synthesis of CAPE by an ultrasound‐assisted packed‐bed bioreactor uses mild reaction conditions. Enzymatic synthesis of CAPE is suitable for use in the nutraceutical and food production industries. Copyright © 2011 Society of Chemical Industry     

Simultaneous degradation of atrazine and simazine by a binary culture of Stenotrophomonas maltophilia and Arthrobacter sp. in a two‐stage biofilm reactor

BACKGROUND: The impact of mixtures of chloro‐triazinic herbicides, such as atrazine and simazine, on aquatic ecosystems is of environmental concern. To study their biodegradation under various operational conditions, a binary community comprising Stenotrophomonas maltophilia and Arthrobacter sp. attached to the porous support of a packed bed reactor, was evaluated. RESULTS: The genetic analysis of the two atrazine‐degrading strains revealed that genes atzA, atzB, atzC are present in both bacteria, but only S. maltophilia possess atzD. Thus, by cultivating Arthrobacter sp. on these herbicides, cyanuric acid accumulation was observed. When the binary community was cultivated in the biofilm reactor, at all the loading rates probed, both herbicides were entirely removed. However, complete biodegradation of cyanuric acid was not achieved. CONCLUSIONS: Even with a two‐stage reactor, cyanuric acid was only partially removed. This fact could be attributed to the absence, in the second stage, of an easily degradable energy source, required by S. maltophilia for the uptake and cometabolic degradation of the recalcitrant heterocyclic ring. Responding to differences in nutritional conditions prevailing at each reactor stage, local differences in species' predominance were clearly detected by microbiological and molecular biology methods. Copyright © 2010 Society of Chemical Industry     

热电阻测控仪表的研制

本文介绍的用ＡＴ８９Ｃ２０５１实现的集双路光柱、数字显示于一体，并具有控制和通信功能而且便于扩充的测控仪表。详细说明输入通道、线性化方法等方面的技术。     

Chemical heat-pump system working at exhaust temperatures of high-temperature-gas-cooled reactor

A chemical heat-pump system using two hydrogen-absorbing alloys is proposed to utilize heat exhausted from a high-temperature source such as high-temperature-gas-cooled reactor, HTGR, which is designed to produce H₂ more efficiently. The overall system proposed here consists of HTGR, He gas turbines, chemical heat pumps and reaction vessels corresponding to the three-step decomposition reactions comprising the I–S process. A fundamental research is performed experimentally on heat generation in a single bed packed with a hydrogen-absorbing alloy that works at the H₂ production temperature. The hydrogen-absorbing alloy of Zr(V_1−xFe_x)₂ is selected as a material that has a proper plateau pressure for the heat-pump system operated between the input and output temperatures of HTGR. Temperature jump due to heat generated when the alloy absorbs H₂ proves that the alloy–H₂ system can heat up the exhaust gas even at 600 °C without any external mechanical force.