Selective Removal of Carbon Dioxide from Wet CO2/H2 Mixtures via Facilitated Transport Membranes containing Amine Blends as Carriers

The selective separation of carbon dioxide (CO₂) from a wet gaseous mixture of CO₂/H₂ through facilitated transport membranes containing immobilized aqueous solutions of monoethanolamine (MEA), diethanolamine (DEA), ethylenediamine (EDA) and monoprotonated ethylenediamine (EDAH⁺) and their blends was experimentally investigated. The effect of CO₂ partial pressure, amine concentration, feed side pressure and amine species on the CO₂ and H₂ permeances were studied. The CO₂ permeability through amine solution membranes decreased with increasing CO₂ feed partial pressure but the H₂ permeance was almost independent of the H₂ partial pressure. A comparison of experimental results showed that single or blended amines with low viscosity and a moderate equilibrium constant, i.e., large forward and reverse reaction rate of CO₂‐amine, are suitable for effective separation of CO₂. The permeability of CO₂ generally increased with an increase in amine concentration, although this increase may be compromised by the salting out effect and decrease in diffusivities of species. The results obtained indicated that CO₂ permeance across a variety of amines are in the order of DEA (2 M) > MD (2 M) > MD (1 M) > MEA (2 M) > MEA (4 M) > MD (4 M) > DEA (1 M) > DEA (4 M) > MEA (1 M) for various concentrations of MEA + DEA blend and are in the order of EDAH⁺ (2 M) > DEA (2 M) > MH (2 M) > DH (2 M) > ED (2 M) > EDA (2 M) > MEA (2 M) for various blends of amine.     

Solar powered high voltage energization for vehicular exhaust cleaning: A step towards possible retrofitting in vehicles

This paper proposes a novel way of generating high voltage for electric discharge plasma in controlling NO_x emission in diesel engine exhaust. A solar powered high frequency electric discharge topology has been suggested that will improve the size and specific energy density required when compared to the traditional repetitive pulse or 50 Hz AC energization. This methodology has been designed, fabricated and experimentally verified by conducting studies on real diesel engine exhaust.     

Dynamic stiffness removal for direct numerical simulations

A systematic approach was developed to derive non-stiff reduced mechanisms for direct numerical simulations (DNS) with explicit integration solvers. The stiffness reduction was achieved through on-the-fly elimination of short time-scales induced by two features of fast chemical reactivity, namely quasi-steady-state (QSS) species and partial-equilibrium (PE) reactions. The sparse algebraic equations resulting from QSS and PE approximations were utilized such that the efficiency of the dynamic stiffness reduction is high compared with general methods of time-scale reduction based on Jacobian decomposition. Using the dimension reduction strategies developed in our previous work, a reduced mechanism with 52 species was first derived from a detailed mechanism with 561 species. The reduced mechanism was validated for ignition and extinction applications over the parameter range of equivalence ratio between 0.5 and 1.5, pressure between 10 and 50 atm, and initial temperature between 700 and 1600 K for ignition, and worst-case errors of approximately 30% were observed. The reduced mechanism with dynamic stiffness removal was then applied in homogeneous and 1-D ignition applications, as well as a 2-D direct numerical simulation of ignition with temperature inhomogeneities at constant volume with integration time-steps of 5-10 ns. The integration was numerically stable and good accuracy was achieved.     

A multi-objective model for seasonal personnel reassignment

The focus of this research was the development of a model to address the problem of reassigning summer construction workers to winter snow and ice removal teams in an efficient and cost-effective manner. The model is a multi-objective integer program that can generate the complete and precise trade-off curve between the objectives of minimizing total distance that the reassigned workforce must travel from their respective homes to one of many site locations, and minimizing the maximum distance that any one worker must travel. System constraints include demand requirements for workers at each site and the limited availability of state-owned vehicles that may be issued to workers assigned to remote sites. Details of the model structure and solution procedure are presented together with the results of an actual application.     

云锡矿区井下通风排氡

云南锡矿井下存在着氡,而氡是产生矿工肺癌的主要因素之一,因此通风排氡成为我矿一项迫切需要解决的严重问题。云锡井下作业场所氡污染的主要来源是:采空区积累的高浓度氡的漏入;自然下行风把上部采空区及矿岩裂隙内的高浓度氡的带入;氡从矿岩介质中的渗出。因而形成高浓度氡对井下矿工的危害。针对上述原因,选用了压入式通风,使井巷内气压高于地表气压,以减少氡的漏入、渗出和改变下行风的方向,取得了降氡的良好的效果。此外,在防氡密闭工艺方面,对井巷壁喷涂混凝土防氡复盖层和密闭墙采用水泥砂浆粉面,效果良好。     

工业磷化废水处理的实验研究及应用

文章介绍了目前工业磷化废水处理过程中常用的化学沉淀除磷法,研究了pH、PAM投加量的变化对除磷效率的影响。确定了除磷的最佳工艺条件为:pH为7.5~9之间,PAM投加量为300 mg/L。     

AOA后置短时低氧曝气实现短程硝化反硝化除磷

为培养亚硝酸盐型反硝化聚磷菌实现好氧颗粒污泥（AGS）短程硝化内源反硝化除磷,设置3组同规格以厌氧/好氧/缺氧后置短时曝气（AO₁A-O₂）模式运行的SBR,各反应器好氧段/后置好氧段（O₁/O₂）的曝气强度和曝气时间均不同,通过对比3组反应器60 d的运行情况,探究各系统污染物处理性能和功能菌活性。结果表明,后置短时低氧曝气10 min且O₁、O₂的曝气强度分别为5、2.5 L/(h·L)的R2脱氮除磷效果最佳,其COD、TP、NH+₄-N、TN去除率达95.49%、95.57%、100%、95.52%。通过短时好氧饥饿和低溶解氧可以创造出短程硝化内源反硝化除磷的最适环境,R2中约60%的除磷菌为DPAOs,且亚硝酸盐型聚磷菌最多,可达38.76%,其反应器好氧段的亚硝酸盐积累率(R_NA)为74.19%,实现了较高的NO-₂-N积累,游离亚硝酸(FNA)为1.03 μg/L,可抑制PAOs和NOB,同时富集出更多的AOB和DPAOs。     

铝电解质中的钾脱除技术

针对我国西南地区铝电解质中钾含量偏高的问题,提出了铝电解工序钾脱除技术方案。根据某电解铝企业的实际情况,通过取样分析、理论推导,以及浮选分离试验,提出了具体的实施方案,并论证了方案的可行性。研究结果表明：电解质中的KF易挥发并以KAlF4和K2NaAl3F12、K2NaAlF6等固体氟铝酸盐的形态进入铝电解烟气;不同企业的铝电解质中KF含量不同,但电解槽挥发物中KF含量却比较接近;采用收集装置将铝电解烟气中的固体挥发物收集走,使其不再混入载氟氧化铝进入电解槽中,可快速降低铝电解槽中KF的平衡浓度;固体挥发物通过浮选可分离其中的氧化铝和氟铝酸盐,氟铝酸盐可用于制备低温电解质。该方案在技术上具有可行性。     

提高人工湿地脱氮除磷性能的强化技术及其在有色金属工业废水中的应用

人工湿地因具有良好的脱氮除磷性能而广泛应用于生活污水尾水和工业废水的深度处理。然而,随着环保政策要求的日益严格,传统的人工湿地对不同水质污水的处理能力有限,从而导致多数污水处理难以满足达标排放的要求。因此,越来越多的强化技术与手段被应用于人工湿地系统,以增强人工湿地的污染物净化性能。主要从合理设计人工湿地、联合预处理工艺构建复合人工湿地系统以及保温和溶解氧控制等方面综述当前提高人工湿地脱氮除磷性能的强化技术,并简要概述了人工湿地在处理有色金属工业废水中的应用。