离子液循环吸收法在尾气脱硫中的应用

针对冶炼烟气制酸尾气的治理,介绍了一种离子液循环吸收脱硫技术及在制酸尾气脱硫装置中的应用情况。离子液循环吸收法脱硫技术具有脱硫效率高、运行成本低、操作简便、较好回收硫资源等特点。在实际应用过程中,脱硫装置运行稳定。当进吸收塔ρ(SO2)为1 200 mg/m3时,出吸收塔ρ(SO2)为50 mg/m3。     

Concentration of sodium chloride in aqueous solution by chlorodifluoromethane gas hydrate

The decomposition temperature and pressure (quadruple point) of chlorodifluoromethane (R22) gas hydrate in aqueous sodium chloride (NaCl) solution was measured at different NaCl concentrations in the solution as a phase diagram. The operative concentration curve of NaCl was obtained as a function of temperature. The maximum decomposition temperature of R22 hydrate was about 290 K at 0.9 MPa pressure, and it decreased as the NaCl concentration increased in the solution. R22 hydrate caused supercooling, and the supercooling occurrence temperature was much lower than the decomposition temperature. The ultrasonic charge reduced the supercooling of hydration effectively even though the ultrasonic charge did not change the decomposition temperature at all. The concentration experimental results from the several NaCl solutions having different NaCl concentrations were in good agreement with the theoretical operative concentration curve for NaCl.     

填料塔中钠碱溶液脱除烟气中SO_2研究

在内径为400 mm的填料塔内,以Na2SO3为吸收剂进行了烟气脱硫模拟实验研究,重点考察了吸收液pH值、液气比(VL/Vg)、空塔气速、烟气中SO2初始浓度、吸收液温度及吸收剂初始浓度等对脱硫率的影响,确定出各影响因素与脱硫率间的关系及实验室规模下本工艺适宜的操作条件。结果表明,在吸收液pH=6—7、液气比1—2 L/m3、空塔气速1—1.5 m/s、吸收液温度50℃以下、吸收剂Na2SO3初始浓度0.3—0.5 mol/L、进口SO2质量浓度约为4 300 mg/m3时,脱硫率均可大于80%。实验结果可为实际脱硫装置设计及运行提供必要的基础数据。     

Solvent counter-diffusion in gas absorption

The usual design equations for absorption towers are based on the assumption that only one component is diffusing in the gas phase: the counter-diffusion of the solvent is ignored. A correction factor has been developed, based on a solution of the Stefan-Maxwell diffusion equations for the case of two gases diffusing through a stagnant third one. The special case of equimolal counter-diffusion is also considered. The correction factor is obtained by simultaneously solving two non-linear equations. The system ammonia-water-air is used to illustrate the order of magnitude of the error the factor is intended to correct.     

乙酸甲酯中钠离子的测定

钠离子的测定有几种方法,但乙酸甲酯中的钠的测定目前没有合适的方法。通过几种方法对比,找到检测乙酸甲酯中的钠的测定方法。该分析方法操作简单,样品不需要特殊处理,数据稳定可靠。     

煤气水中总铁离子及钙离子的分析

在酸性介质中,Fe2+与邻菲罗啉生成橙红色络合物,在最大吸收波长510nm处,通过测定其吸光度计算铁离子含量.采用EDTA滴定法测定Ca2+.两种离子加标回收率均达到90%以上.测定方法简便快速、准确率高,适合于煤气水中总铁离子及Ce的分析.     

Penetration profile of chloride ion in cracked reinforced concrete

A detailed observation on the penetration profile of chloride ions through and around a crack in reinforced concrete structures was carried out. Electron probe microanalysis (EPMA) and colorimetric tests were conducted on cracked specimens, which were exposed to NaCl solution at a temperature of 20 °C and a humidity of 60% RH, after being conditioned in the same condition for 2 months. Research parameters included water to cement ratio (w/c), single and multicracks, exposed direction, crack width, NaCl solution concentration and cover thickness. Increasing w/c led to a higher ingression rate of Cl⁻ ions, not only from the exposed surface but also around the cracks. It was found that the penetration depth from the surface of the cracks was equal to or slightly higher than that from the exposed surface for higher w/c mixes of 0.45 and 0.65. The transportation of Cl⁻ ion was strongly influenced by the bulk movement of the solution inside the concrete.     

PX氧化鼓泡塔反应器内的TA浓度分布

利用新建的D476鼓泡塔冷模实验装置和沉降—扩散模型对工业鼓泡塔PX氧化反应器内的TA浓度分布进行了实验和数学模拟研究。结果表明,由于PX氧化气速较大,塔内TA浓度接近均匀分布。     

Achieving flue gas desulphurization with membrane gas absorption

Membrane gas absorption (MGA) is an efficient and flexible way to carry out gas-liquid (G-L) contacting operations with hollow fibre membranes. The main advantages of membrane gas absorption over conventional G-L contactors is the compactness and low weight of the installation, the standard modular construction elements and the flexible operation. Gas and liquid flow can be controlled independently in the MGA process, which makes operation over a wide range of liquid and gas flow rates possible. In a MGA installation no entrainment, flooding, channelling or foaming occurs. Rob Klaassen and Albert E Jansen, TNO Environment, Energy and Process Innovation, discuss the principle of this technology, the benefits of newly developed membrane modules and their potential applications.     

Effects of gas concentration on hydrodynamics of gas absorption in a microchannel

In this article, the effects of gas concentration on hydrodynamics of gas–liquid two-phase flow with mass transfer during gas absorption in a microchannel are investigated, by using 2-amino-2-methyl-1-propanol (AMP) solution to absorb mixtures of CO₂ and N₂ with various volume fractions. The concentration of CO₂ not only affects the driving force of gas–liquid mass transfer, but also affects the pressure drop of gas–liquid two-phase flow. The average linear velocity of the liquid phase is estimated by introducing the void fraction, which accurately characterizes the difference in the bubble velocity versus the liquid velocity. On this basis, the pressure drop model of gas–liquid two-phase flow with mass transfer in a microchannel is established. Through the pressure drop model, the influence mechanism of CO₂ concentration on the pressure drop during gas absorption in a microchannel is revealed.     

基于pH测量的CO2吸收到钠基溶液动态实验及模型

采用基于pH测量的CO₂吸收速率研究方法。将pH与溶液中的成分相关联,采用分段拟合获得CO₂吸收速率,获得溶液成分对吸收速率的影响规律。对于低浓度的NaOH来说,吸收速率一直保持不变直到CO₂物理吸收到NaHCO₃溶液中。对于高浓度的NaOH,NaOH完全转化成Na₂CO₃时,吸收速率降低。但在两个吸收阶段中,吸收速率不变,CO₂物理吸收到NaHCO₃中时,吸收速率随CO₂饱和度的增加而降低。对CO₂吸收到NaOH中,CO₂和钠离子浓度都促进吸收,钠离子浓度影响更大;对于CO₂吸收到Na₂CO₃中,当Na₂CO₃浓度大于0.05mol/L,吸收速率不随浓度增加;对于CO₂吸收到NaHCO₃中,低浓度的钠可以促进CO₂吸收,而高浓度的钠抑制CO₂吸收,这主要由于析盐的作用。为避免CO₂大量吸收,优先选择0.5mol/L以上浓度的NaHCO₃。     

Temperature-dependent physical properties in physical gas absorption

A solution for interface temperature rise in physical gas absorption due to heat of solution was obtained by Danckwerts [1,2] with the limitation that the pertinent physical properties—diffusion coefficient, solubility of the gas and thermal conductivity of the liquid remained constant. This paper complements Danckwerts' contribution by considering the pertinent physical properties as temperature-dependent, the dependence being of the form:$\text{Q}\text{Qi}$ = exp [γ_Q(T ? T_i)]. Wagner [3] has obtained solutions for unsteady-state diffusion when the diffusion coefficient is similarly dependent on concentration. Wagner's solutions are adapted to provide a solution for the present problem. Two approximate solutions, one valid at high Lewis Number and the other when Lewis Number approaches unity are also presented. For the normal values of activation energies, Danckwerts' model is shown to be accurate when interfacial temperature rise is less than one percent of the absolute temperature of bulk liquid. The extent of departure from the Danckwerts' model is shown to depend on combinations of activation energies of the pertinent physical properties.     

Kinetics of oxygen absorption in aqueous sodium dithionite solutions

The absorption and reaction of oxygen in aqueous alkaline solutions of sodium dithionite has been experimentally investigated in a novel gas-liquid contactor. The novel gas-lift bubble column contactor was used to study the kinetics over wide ranges of reactant concentrations, temperature, and pH. The oxygen-sodium dithionite reaction was found to be first-order with respect to dithionite in the range of dithionite concentration < 0.1 M, and second-order in the range of dithionite concentration > 0.1 M. The reaction with respect to oxygen was found to be zero-order for all dithionite concentrations. These results and experimental investigations of the effect of solution alkalinity and temperature on the reaction rate are consistent with previous findings obtained in different gas-liquid contactors. The results thus confirm the feasibility of using the gas-lift bubble column for the kinetics of gas-liquid reactions.     

氯气吸收系统改造

在离子膜和隔膜烧碱系统开停车和发生突发事故时,通过对淡氯塔和事故塔未吸收完全的尾气进行二级吸收处理,达到保护人身安全和环保排放的目的。实践证明,该工艺能满足大中型氯碱装置的安全环保生产需要。     

氯化钠在微波干燥中的动态吸波效率研究

为了研究物料在微波干燥过程中的动态吸波效率,文中将反射损耗理论引入其中,计算了2.45 GHz微波频率下,20℃时含水率为1%—5%以及含水率为4%的氯化钠在20—100℃的反射损耗系数。计算结果显示,厚度为0.014 m含水率4%的氯化钠在60℃取得最大的微波吸收效率,达到-68 dB;不同含水率的氯化钠反射损耗系数随着厚度的增加,会按照含水率由高到低的顺序依次出现吸波峰。研究结果表明,只有在对应小于1/8波长的吸收峰偏移的较小厚度下,氯化钠才能在整个微波干燥过程中一直取得较高的吸波效率。     

Surfactant effects on gas absorption in a coke-oven gas treatment process

The effect of organic impurities in industrial stripped coal water (SCW) on the absorption of CO₂ was measured experimentally. Removal of these impurities via activated carbon showed a marked improvement in interphase mass transfer of a vertical wetted-wall column absorber. However, this benefit was not found in a stirred-cell absorber, in which a different flow pattern from that in wetted-wall column absorber is expected. An ad hoc systematic study on the effects of three deliberately added surfactants on gas absorption by pure water in three different absorbers with different flow patterns was thereafter conducted. The experimental results reveal that absorption deterioration also prevails only in a vertical, wetted-wall column absorber and the reduction in liquid phase mass transfer by the addition of surfactant can be satisfactorily correlated with surface pressure of solutions. This indicates that the effect of the industrial impurities in SCW on gas absorption may successfully be simulated under the same flow pattern by a surfactant solution with the same surface pressure. A possible modification of the existing coke-oven gas (COG) treatment process for the benefit of absorption enhancement was finally proposed.     

膜吸收在烟气净化中的应用

膜吸收法是膜分离技术与气体吸收技术相结合的一种新型烟气净化技术,具有传统吸收法和膜分离技术的共同优点。介绍膜吸收法净化烟气的基本原理、常用的膜材料,阐述烟气脱硫/脱硝、脱碳的研究进展。通过膜吸收技术与传统烟气吸收技术对比,表明膜吸收技术在经济性能和环保方面具有优势,应用前景广阔。     

低聚果糖促进钙离子吸收的研究

首先介绍了低聚果糖促进钙离子吸收的实验,简要分析了这一现象的原理,最后展示了几种应用低聚果糖的补钙产品。     

含碘吸收液中碘离子含量的测定

对含碘吸收液中碘离子含量进行定性及定量检测后,选用Fajans法对其中所含碘离子进行测定,测定结果稳定、可靠,测定方法简捷、可操作性好。