电渗析处理焦化废水反渗透浓水的工程应用研究

结合某焦化废水深度处理与回用工程项目,考察了电渗析处理焦化废水反渗透浓水的状况和不同工艺参数对膜性能的影响,明确电渗析处理焦化废水反渗透浓水的脱盐率和能耗。结果表明,焦化废水反渗透浓水污染物对电渗析膜污染较重,可用1%稀盐酸洗涤恢复膜性能。2台电渗析膜堆串联组合处理焦化废水反渗透浓水,脱盐率和吨盐能耗随操作电压的增大而增大。固定操作电压为250 V,淡化液流量为9 m3/h,在此条件下膜堆脱盐率为51%,吨盐能耗为625 k W·h。     

含盐乙二醇溶液电渗析脱盐工艺研究

针对陆域油气体开采过程中产生的乙二醇盐溶液,设计了处理规模为100 L/h的3级串联电渗析连续化脱盐工艺,在不同操作电压条件下分析了系统脱盐率、能耗、乙二醇损失率以及各级电渗析脱盐率的变化特性。结果表明,操作电压为80 V时,脱盐率可达到90%,能耗仅为0.792 kW·h/m3,此时乙二醇损失率为0.51%。操作过程中当前2级电渗析以较大操作电压运行时,可通过适当降低第3级电渗析的操作电压以减少能耗。     

无机高盐废水电渗析规律的研究

考察了自制一级一段式电渗析装置在焦化厂的高盐、高硬度废水中的脱盐效果和规律。为了防止结垢对膜组件的影响,首先对高盐、高硬度废水进行了软化处理,随后确定了该软化废水的分解电压,最后详细考察了运行时间、电压、中间室废水流量及阴、阳极室废水流量对电渗析脱盐效率的影响规律。结果表明,电渗析脱盐效率随运行时间的延长而逐步下降,随着电压的升高而增大,随中间室流量的减小而增加,随阴、阳极室流量的增大而升高。当操作电压为2.8 V,中间室流量为78 mL·h^-1,阴、阳极室流量为42 mL·h^-1,连续运行30和60 min时的平均脱盐效率分别为6.7%和6.4%。     

电渗析对飞机除冰废水脱盐性能的研究

通过电渗析对飞机除冰废水的脱盐性能进行了初步研究,采用电导率来表征废水的脱盐率,并考察了其影响因素。结果表明,电渗析对废水的脱盐率不低于90%,乙二醇收率约为99%。操作电压对脱盐时间影响明显,适宜电压为12~14 V,废水中的乙二醇浓度越高,废水的脱盐时间越长,而脱盐时间越长,脱盐过程中乙二醇的损失越大。     

电渗析耦合蒸汽机械再压缩技术深度处理化工阻燃剂废水研究

针对单一蒸汽机械再压缩(MVR)技术处理阻燃剂化工废水能耗相对较高的问题,采用电渗析(ED)耦合MVR技术的新型模式,对阻燃剂废水进行深度脱盐及脱COD处理的同时降低系统总能耗。电渗析阶段考察不同的水回收率、不同电压及不同流量下的废水处理效果;最终阶段采用MVR工艺处理电渗析浓室产水,并对过程能耗模拟分析。结果表明,当电渗析采用恒压为25 V、体积流量为15 L/h、电渗析水回收率为67%时,耦合工艺的总能耗与单一使用MVR相比降低了48.8%;同时整体工艺的水回收率提高至95%。     

浓水流量对电渗析脱盐过程性能参数的影响

采用电渗析装置,对苦咸水脱盐过程进行了研究。考察了浓水流量、操作电压对膜堆电流、电阻、脱盐率、系统能耗的影响。结果表明,提高浓水流量与加大操作电压均使电渗析的传质通量（脱盐率）和操作电流提高,系统能耗增大。膜堆电阻变化较为复杂,操作电压＜20 V时,膜堆电阻降低;操作电压为20~30 V时,膜堆电阻基本保持不变;操作电压＞30 V时,膜堆电阻增大。     

电解电渗析联合处理含铜废水

研究了电解电渗析联合处理含铜废水的可行性.结果表明:电解铜回收率随电压和进水质量浓度升高、进水流量降低而提高.在U=4.5 V,p(Cu2+)进水为500 mg/L,q进水为1 L/h时,铜最高回收率为70%,能耗是11(kW·h)/kg.电解后尾液再经电渗析继续处理,淡水中铜的去除率约为98%,浓水的浓缩倍数在2以上,能耗为0.9～3.0(kW·h),可再进行电解回收.经X-射线衍射仪观察,回收铜几乎为100%,回收铜的粒径随电流密度增加而增加.     

电渗析+铁碳+生化组合法处理苯酚丙酮废水

采用电渗析+铁碳+生化组合处理法对实际苯酚丙酮废水的处理效果和影响因素进行实验研究。结果表明,电渗析汲盐液浓度及膜堆电压对废水脱盐效率及能耗有显著影响,在汲盐液初始质量浓度为20 g/L Na_2SO_4、电压为14 V条件下,经210 min废水盐质量浓度从66.7 g/L降到8 g/L左右,脱盐率达到88%,具有较高的效率和经济性;脱盐后的废水经1.5 h铁炭微电解处理,BOD5/COD提高到0.31,最后生化处理出水COD约为130 mg/L,组合处理法的COD总去除率达到96.7%。     

均相膜电渗析脱除氨法脱硫浆液中氟离子

鉴于烟道气氨法脱硫浆液中F-的危害性,在基本不影响硫酸铵的前提下采用均相膜电渗析脱除浆液中的F~-,考察了电渗析运行参数和浆液性质对F-迁移量的影响,并考察了硫酸根的截留效果。结果表明,F~-迁移量随电压和循环流量的增大而增加,但过高的电压会增加能耗,过高的循环流量会降低传质的几率,降低F-迁移量,均相膜电渗析较佳的运行参数为电压15 V,浓、淡液循环流量为200 L/h。随着温度和F~-初始质量浓度的升高,F-迁移量增大,(NH_4)_2SO_4质量分数对F-迁移量影响较小。均相膜电渗析对SO_4~(2-)的截留效果较好,可以在脱除F~-的同时更好地保留脱硫浆液中资源化回收成分硫酸铵。     

电渗析浓缩垃圾焚烧飞灰水洗废水研究

采用间歇电渗析法和连续电渗析法对去除重金属后的垃圾焚烧飞灰水洗废水中KCl、CaCl₂、NaCl等混盐进行浓缩工艺的研究,考察了电压、水洗废水温度、补料流量、水洗废水盐含量等因素对电渗析浓缩过程中混盐质量浓度、混盐回收率以及膜堆单位能耗的影响。结果表明,电压、温度、补料流量、水洗废水盐含量影响较大。在电压为12 V,水洗废水温度为25 ℃,补料流量为5 L/h、水洗废水盐含量46.70 g/L条件下,浓缩后水洗废水中的混盐质量浓度从46.70 g/L浓缩至187.29 g/L,混盐回收率为50.53%,膜堆单位能耗为170.79 kWh/t_混盐,表现出了良好的盐浓缩性能。     

Removal of zinc ions in wastewater by electrodialysis

To obtain useful data for treatment of the wastewater discharged from zinc electroplating processes, we investigated the effects of operating parameters, such as the initial concentration of dilute solution, the flow velocity and the applied voltage, on removal rate of Zn²⁺ in the model solutions using an electrodialysis system. Zinc ions in the solutions were effectively removed by the electrodialyzer with CMX cation exchange membranes and AMX anion exchange membranes. The initial concentration of dilute solution, the flow velocity and the applied voltage strongly affected the performance of the electrodialysis system. As the initial concentration of dilute solution, the flow velocity and the applied voltage were increased, the removal ratio was increased. The energy consumption was increased as the initial concentration of dilute solution and the applied voltage were increased, whereas the effect of the flow velocity on the energy consumption was negligible.     

Development of an electrodeionization process for removal of nitrate from drinking water Part 1: Single-species testing

A bench-scale study was performed to develop and evaluate the use of electrodeionization as a technology for the removal of nitrate from drinking water. Electrodeionization is an emerging technology that combines electrodialysis and ion exchange. Treatment of distilled water that was dosed with sodium nitrate was studied. The impact of design and operating conditions on nitrate flux and energy consumption for nitrate removal was evaluated. Increasing the voltage applied to the unit resulted in an increased nitrate flux out of the water stream but resulted in an increased energy consumption per equivalent of nitrate removed. Increasing the membrane spacing resulted in decreased fluxes and increased energy consumption. The type of resin employed in the process clearly had an impact on the fluxes, and the presence of any anion-exchange resin resulted in an improved performance compared to operation in the electrodialysis mode. Increasing the number of membrane pairs in the unit resulted in a decreased nitrate flux but appeared to have little impact on the energy consumed. Nitrate fluxes increased with nitrate concentration but appeared to approach a maximum flux at very high concentrations. At lower nitrate concentrations there was an increased energy consumption that likely resulted from the electrolysis of water at the lower ionic strength. Increasing the process flow rate appeared to have little impact on nitrate flux but resulted in higher energy consumption. Operation in recycle mode produced similar results to the once-through mode when conditions of similar outlet water composition were compared.     

Comparison of electrodialysis and reverse electrodialysis processes in the removal of Cu(II) from dilute solutions

Electrodialysis (ED) and electrodialysis reversal (EDR) processes have been often used for separation of ions in dilute solutions. In this study, the performance of ED and EDR processes has been examined in the removal of copper from the dilute solutions. First, applied voltage, initial concentration, flow rate, type of electrolyte and the effect of concentration were determined for both processes. Then, separation efficiency, current efficiency, energy requirement and material flux of the processes were calculated, and the performances of the processes were compared. The separation efficiency and energy consumption of EDR process were higher compared to ED process under equal operating conditions. Also, the current efficiency (39.58%) of EDR process was lower than the current efficiency (67.46%) of ED process. It can be said that the ED process is more suitable in terms of energy consumption for separation in the low flow rate and concentration.     

1,3-丙二醇发酵液电渗析脱盐的中试研究

在1,3-丙二醇发酵液电渗析脱盐小试研究的基础上进行了中试研究,着重考察了浓淡室流速、浓室初始浓度和膜对电压对电渗析操作过程的影响,通过综合比较脱盐时间、电流效率、能耗等一系列指标,确定了中试条件下脱盐工艺的最佳操作条件。     

双极膜电渗析处理生物质水解液的过程性能研究

在由双极膜和阴离子交换膜组成的两室双极膜电渗析装置中,研究了生物质水解液糖、酸分离和酸回收的过程性能。考察了不同膜对、进料浓度、电流密度、处理室循环流量及操作温度等因素对于处理水解液过程中的电流效率和平均功耗的影响。结果表明,由BP-1双极膜与A501SB阴离子交换膜组成的膜对的性能最佳;过程的电流效率随进料液酸浓度的增大而下降,过高酸浓度的水解液进料对电渗析分离过程不利;较高操作电流密度条件下电流效率高,利于降低功耗,本装置的处理室适宜循环流量为30.0 mL/m in;操作温度的升高,对提高电流效率作用不明显,但利于降低平均功耗,本实验装置的合适操作温度为35℃。     

Tailoring of Seebeck coefficient with surface roughness effects in silicon sub-50 nm films

ABSTRACT: The effect of surface roughness on the seebeck coefficient in the sub 50 nm scale silicon ultra thin films is investigated theoretically using nonequilibrium Green's function formalism. For systematic studies, the surface roughness is modelled by varying thickness periodically with square wave profile characterized by two parameters: amplitude (A0) and wavelength (lambda). Since high Seebeck coefficient is obtained if the temperature difference between the ends of device produces higher currents and higher induced voltages, we investigate how the generated current and induced voltage is affected with increasing A0 and lambda. The theoretical investigations show that pseudoperiodicity of the device structure gives rise to two effects: firstly the threshold energy at which the transmission of current starts is shifted towards higher energy sides and secondly transmission spectra of current possess pseudobands and pseudogaps. The width of the pseudobands and their occupancies determine the total generated current. It is found that current decreases with increasing A0 but shows a complicated trend with lambda. The trends of threshold energy determine the trends of Seebeck voltage with roughness parameters. The increase in threshold energy makes the current flow in higher energy levels. Thus the Seebeck voltage i.e. voltage required to nullify this current increases. Increase in Seebeck voltage results in increase in Seebeck coefficient. We find that threshold energy increases with increasing A0 and frequency (1/lambda). Hence Seebeck voltage and Seebeck coefficient increases vice versa. It is observed that Seebeck coefficient is tunable with surface roughness parameters.     

液隙式热泵膜蒸馏海水淡化系统的热力性能分析

热泵膜蒸馏是一种新型的膜分离技术,在处理高浓度盐水方面具有很大的优势,而目前的热泵膜蒸馏系统存在渗透量较低、冷却水消耗量大等问题。为提高渗透量、减少冷却水的消耗,设计了一种新型液隙式热泵膜蒸馏的海水淡化系统,通过在Aspen Plus中自定义膜模块建立经过实验验证的系统仿真模型,研究了进料液温度、渗透侧温度及进料流量对系统膜通量及能效比等热力参数的影响。结果表明,渗透侧温度降低可引起渗透量增加和能效比减小,且在低渗透侧温度情况下渗透侧温度的改变对能效比影响更大。随着渗透侧温度变化,存在一个渗透侧温度使造水比最大且吨水能耗最小,研究工况下最大造水比可达3.42,最小吨水能耗为463 MJ/t,且该最佳渗透侧温度随进料液温度增加而增加。进料液流量增加可引起渗透量和能效比增加,引起吨水能耗升高和造水比降低,当进料液流量小于3 L/min时,进料液流量增加对吨水能耗和造水比的负面影响较显著,进料液温度为50℃时,料液流量从1.5 L/min增至3 L/min,造水比的降低幅度可达33.5%;料液流量从4.5 L/min增至6 L/min时,造水比的降低幅度降至10.6%。     

烟气脱硫产物亚硫酸铵非催化氧化动力学

采用搅拌反应器,通过改变初始亚硫酸铵浓度、pH值、空气流量、温度以及硫酸铵浓度、不加催化剂,对氨法烟气脱硫产物亚硫酸铵氧化反应动力学进行了研究。实验结果表明:在硫酸铵浓度为0.15 mol/L、温度为35～60℃的溶液中、氧化空气流量为150～400 L/h时,亚硫酸铵的氧化速率随着pH值增加而下降,随着温度和空气流量的增加而增大;当硫酸铵浓度增大时,亚硫酸铵的氧化速率下降;在pH值为5.5时反应的活化能为31.88 kJ/mol。     

Response surface modeling and optimization of electrodialysis for reclamation of RO concentrates in coal-fired power plants

ABSTRACT

Response surface methodology was employed to model and optimize the electrodialysis process for Reverse osmosis concentrate (ROC) reclamation in coal-fired power plants. Predictive models were developed for simulation of different input parameters and responses of ED process. The model for responses was statistically verified by analysis of variance which generated a high coefficient of determination value. Moreover, regression analysis showed a good repeatability and agreement of the experimental data to a quadratic model. The optimum operating parameters were found to be 5.9 V of operational voltage, 1.19 m/s of flow rate and 74 min of time. And the corresponding energy consumption and desalination rate were 0.11 Wh/L and 75.3%, respectively.