Absorption of Low Concentration Sulfur Dioxide Using Liquid-containing Microporous Membrane

The absorption of low concentration SO2 in flue gas by using the module of liquid-containing microporous membrane which is made up of hollow fiber and citric acid-sodium citrate buffer solution was investigated. The absorption efficiency of hydrophilic and hydrophobic membranes by using the concept of dynamic contact angle was mainly studied. The influences on absorption efficiency from absorption time, flowrate of gas phase, SO2 concentration of gas phase, air pressure, citrate concentration, pH value of solution as well as the generation of sulfate radical in absorption solution were examined. The results indicate that the hydrophobic hollow fiber membrane is better than hydrophilic membrane, the absorption efficiency decreases with increasing absorption time, gas phase flowrate, gas phase SO2 concentration and air pressure, the absorption rate and capacity of SO2 can be improved by increasing the citrate concentration, the absorption efficiency can be improved by increasing the pH value of citrate solution, the concentration of SO42- in absorption solution increases linearly with the absorption time at a rate around 0.192 g/(L×h).     

Theoretical Study on Sulfur Dioxide Absorption with Citrate Solution

The citrate absorption of SO2 is currently one of the most successful and economic methods to harness sulfur dioxide pollution. In order to theoretically elucidate the mechanism of SO2 absorption by citrate solution and provide theoretical instruction for experiments and industrial process, the theory of multi-buffer solution, combined with computer numerical calculation methods, was applied to study the distribution parameters of the components of the citrate solution in the process of SO2 absorption and the following results were obtained: (1) HCi2- and H2Ci- in the citrate solution played the dominant role in the absorption and desorption processes; (2) Through the calculation for the buffer capacity of citrate solution, it was found that the pH of the absorption and desorption solution should be in the range of 2~8, while at pH=4.5 the buffer capacity reached its maximum. Some valuable parameters were obtained, which are instructive to the ensuing experiments and industrial design.     

填料塔中碳酸钾/哌嗪混合吸收液脱除CO2的体积传质系数

The process of removing dilute CO2 from air by using me mixtures of K2CO3 and piperazine (PZ) was conducted in a random packed tower at 25℃. The results showed that PZ increased the absorption rate of CO2 into aqueous K2 CO3 much more effectively than MEA or DEA. The volumetric overall mass transfer coefficient (KGa) of dilute CO2 absorption into K2CO3/PZ was measured. The KGa value was evaluated over the ranges of main operating variables: the concentration of CO2 in inlet gas, gas flow rate, liquid loading, CO2 loading in liquid phase, and the concentrations of K2CO3 and PZ. The test showed that KGa could be remarkably improved by increasing liquid loading and the concentration of PZ, and decreasing the concentration of CO2 in inlet gas, as well as the gas flow rate and CO2 loading in liquid phase.     

超声波解吸柠檬酸盐溶液中二氧化硫的研究

Using a sonochemical reactor designed by the authors,the process of removing sulfur dioxide from cit- rate solution simulating the flue gas desulfurization was studied.The influence of ultrasonic frequency,ultrasonic power,reaction temperature,stirring speed,inert gases,initial concentration of sulfur dioxide and concentration of citrate on the efficiency of sulfur dioxide desorption,the stability of citrate solution and the concentration of sulfate radical was examined systematically.By comparing the desorption of sulfur dioxide with and without ultrasonifica- tion,it was concluded that(1)lower ultrasonic frequency results in a better degassing efficiency;(2)the use of ul- trasonification in desorbing sulfur dioxide from citrate solution improves the desorbing efficiency in some condi- tions,without changing the essence of chemical reactions;(3)sparging inert gas into the liquid can lower the vis- cosity of solution and the cavitating threshold,and raise the desorption efficiency.These results demonstrate a technical way for deep desorption of sulfur dioxide and provide the fundamental data for future industrial disposal of sulfur dioxide.     

Experimental and Theoretical Studies on Desulfurization Efficiency of Dual-alkali FGD System in a RST Scrubber

The effects of operating parameters on desulfurization efficiency of a dual-alkali FGD process in a rotating-stream-tray (RST) scrubber are investigated. A dimensionless factor, e, is proposed in this study to predict desulfurization efficiency of this dual-alkali FGD system. e represents the desulfurization ability of a dual alkali FGD system, determined by five main operating parameters such as sodium ion concentration, ratio of absorbent flow rate to flue gas flow rate, pH value of absorbent solution, ratio of sulfate ion to total sulfur ion in absorbent solution, and sulfur dioxide concentration of inlet flue gas. The empirical expression for predicting desulfurization efficiency at different temperatures is obtained through the experimental study and theoretical calculation. It provides useful guide for engineering design.     

Study on Desorbing Sulfur Dioxide from Citrate Solution by Ultrasonlficatlon

Using a sonochemical reactor designed by the authors, the process of removing sulfur dioxide from citrate solution simulating the flue gas desulfurization was studied. The influence of ultrasonic frequency, ultrasonic power, reaction temperature, stirring speed, inert gases, initial concentration of sulfur dioxide and concentration of citrate on the efficiency of sulfur dioxide desorption, the stability of citrate solution and the concentration of sulfate radical was examined systematically. By comparing the desorption of sulfur dioxide with and without ultrasonification, it was concluded that （1） lower ultrasonic frequency results in a better degassing efficiency; （2） the use of ultrasonification in desorbing sulfur dioxide from citrate solution improves the desorbing efficiency in some conditions, without changing the essence of chemical reactions; （3） sparging inert gas into the liquid can lower the viscosity of solution and the cavitating threshold, and raise the desorption efficiency. These results demonstrate a technical way for deep desorption of sulfur dioxide and provide the fundamental data for future industrial disposal of sulfur dioxide.     

旋转填料床中硝酸吸收NO_x的实验研究(英文)

Absorption of NOx into nitric acid solutions was studied in the presence of ozone by using a rotating packed bed (RPB) contactor. The influences of operating parameters, such as high gravity number, amount of ozone, gas velocity, liquid spray density and inlet concentration of NOx, on the removal efficiency of NOx were investigated, among which the high gravity number and ozone amount are more important. Ozone was introduced to oxidize HNO2 to HNO3 to prevent the decomposition of HNO2 in the liquid phase. The high gravity number presents the effective external force for enhancing the mass transfer of ozone from gas phase to liquid phase. Under the experimental condition, the removal efficiency of NOx is higher than 90% and the concentration of nitric acid product exceeds 45%.     

陶瓷球填料生物滴滤塔降解甲苯废气

The Purification experiments of waste gas containing low concentration toluene were made in trickling biofilter with ceramic spheres. The effects of liquid flow rate,gas flow rate,pH of circulation liquid, and toluene concentration in inlet gas on the purification efficiency of trickling biofilter were investigated. The pressure drop of the trickling biofilter was also measured during experiments.Increasing liquid flow rate and gas flow rate resulted in the decrease of purification efficiency of trickling biofilter. The highest purification efficiency of trickling biofilter was found at the circulation liquid pH of 7. The porosity of the packing material at the inlet of gas was higher than that at the outlet of gas in biofilter after continuous operation in 50 days. The decrease in the porosity of packing material caused a great increase in the pressure drop of the biofilter.     

Desorption of VOC from polymer adsorbent in multistage fluidized bed

The desorption process of volatile organic compounds(VOC) from a polymer adsorbent in counter-current multistage fluidized bed was studied. And a mathematical model considering the mass transfer dynamics was developed, which was validated from experiment data. The gaseous ethyl acetate mass transfer was discussed, and the limiting step is the intraparticle mass transfer of the desorption process. The value of intraparticle mass transfer coefficient is between 1.85 × 10~(-6) and 1.38 × 10~(-5) m·s~(-1) under temperature of 100–160 °C. Experiments under different operating conditions were carried out. The effects of operating conditions such as gas–solid flow ratio,gas inlet temperature and total stage number of multistage fluidized bed on outlet VOCs concentration and desorption efficiency were discussed. The maximum outlet VOCs concentration and corresponding desorption efficiency of the multistage fluidized bed desorber was calculated under different gas inlet temperatures and total stage numbers.     

Hydrogen sulfide removal by catalytic oxidative absorption method using rotating packed bed reactor

Using catalytic oxidative absorption for H_2S removal is of great interest due to its distinct advantages. However,traditional scrubbing process faces a great limitation in the confined space. Therefore, there is an urgent demand to develop high-efficiency process intensification technology for such a system. In this article, H_2S absorption experimental research was conducted in a rotating packed bed(RPB) reactor with ferric chelate absorbent and a mixture of N_2 and H_2S, which was used to simulate natural gas. The effects of absorbent p H value, gas–liquid ratio, gravity level of RPB, absorption temperature and character of the packing on the desulfurization efficiency were investigated. The results showed that H_2S removal efficiency could reach above 99.6% under the most of the experimental condition and above 99.9% under the optimal condition. A long-time continuous experiment was conducted to investigate the stability of the whole process combining absorption and regeneration. The result showed that the process could well realize simultaneous desulfurization and absorbent regeneration, and the H_2S removal efficiency kept relatively stable in the whole duration of 72 h. It can be clearly seen that high gravity technology desulfurization process, which is simple, high-efficiency, and space intensive, has a good prospect for industrial application of H_2S removal in confined space.     

高效填料塔中用柠檬酸/柠檬酸钠溶液进行烟气脱硫的研究

以柠檬酸 柠檬酸钠溶液为缓冲液在高效规整填料塔中进行烟气脱硫。模拟的烟气首先在吸收塔中用柠檬酸钠溶液脱硫 ,然后富液在解吸塔中释放出SO2 ,再生的缓冲液返回吸收塔循环使用。研究了影响吸收及解吸效率的各种重要参数 ,确定了最佳操作条件。对解决SO2 污染问题提供了应用基础     

规整丝网填料旋转填充床的气相压降特性及脱硫性能

采用空气-水体系,对装有4种不同规格规整丝网填料的旋转填充床的压降特性进行了实验研究,考察了转速、气体流量、液体流量等操作参数及填料特性对气相压降的影响规律,并与传统不锈钢波纹丝网填料旋转填充床压降进行了比较. 结果表明,装有规整丝网填料的旋转填充床压降可降低35%~70%. 进一步采用压降较低的规整丝网填料以(NH4)2SO3为吸收剂进行氨法脱硫性能研究,结果表明,随转子转速和(NH4)2SO3浓度增大,SO2脱除率升高;随进气口SO2浓度升高及气液比增大,SO2脱除率降低;SO2脱除率最高可达97%,可满足国家排放标准.     

填料塔中柠檬酸盐溶液脱除低质量浓度SO2的特性

研究了用柠檬酸盐溶液在波纹填料塔中吸收高氧含量烟气中低质量浓度SO2的特性,重点考察了柠檬酸浓度、溶液的pH、烟气流量对吸收效果的影响,确定出溶液中SO2质量浓度与烟气中SO2脱除率的关系,测定出吸收溶液中亚硫酸根的氧化速率,证实了溶液中硫酸根的质量浓度基本呈线性增加,增加的速率约为0.2g/(L·h)。     

多管文丘里洗涤器烟气脱硫的实验研究

设计搭建了文丘里洗涤器模拟实验装置,分别以氢氧化钠和氢氧化钙为脱硫剂,进行冷态实验,研究了吸收液浓度、液气比、喉管气速和入口二氧化硫浓度对脱硫效率的影响,得到了最佳操作工况。     

喷淋塔氨法脱硫实验研究

文章在喷淋实验塔中,研究了氨法烟气脱硫的特性。将空气和气态二氧化硫按一定比例混合后的气体作为模拟烟气,用氨水作为脱除二氧化硫的吸收剂,对模拟烟气的进气温度、进气浓度、气速、液气比以及吸收液的pH五个因素对脱硫率的影响进行了逐一考察,获得了各因素与脱硫率之间的关系,并得到较适宜的操作参数。实验结果表明：随着液气比和吸收液pH的增大,脱硫率增大。随着模拟烟气进气温度、进气浓度和气速的增大,脱硫率降低。其中温度因素对脱硫率的影响不明显。实验得到适宜的操作参数为：常温下,模拟烟气气速为2．0m／s,液气比为10,pH为6．4时,对浓度为2000mg／m^3的烟气操作,收率可维持在85％以上,并在理论上对各因素和脱硫率之间的内在联系作了理论分析。     

填料塔中哌嗪二胺吸收低浓度SO_2的传质性能

为满足有机胺法脱硫设计开发的需要,采用动态吸收法测定了填料塔中哌嗪二胺(PA-A)水溶液吸收低浓度SO2的体积总传质系数KGa,考察了吸收工艺参数如吸收液中的PA-A浓度和初始pH值、液相流率、吸收温度、进气SO2浓度及流速等对KGa的影响。结果表明:KGa随着吸收液中的PA-A浓度和初始pH值、液相喷淋密度的增加而增大;随着吸收温度、气相流率及进气SO2浓度的增加而减小。通过实验结果分析得到体积总传质系数KGa与气液相流率比(qG/qL)之间符合指数关系式,该经验关系可用于工程设计计算。     

新型旋转填料床脱除烟气中SO2的实验研究

在新型旋转填料床中以NaOH为吸收液脱除烟气中的SO2,考察了超重力因子、液气体积比、进气量等因素对脱硫率(h)和气相传质系数(KGa)的影响及循环次数对脱硫率和溶液pH值的影响. 结果表明,h随超重力因子、液气体积比增加而增加,随进气量增加而降低;KGa随超重力因子、液气体积比、进气量增加而增加. 脱硫率和溶液pH值随循环次数增加呈下降趋势. 最佳操作条件为：超重力因子67,进气量55 m3/h,液气体积比(1.1~1.3)′10-3. 在该条件下,出口气体中SO2浓度低于100 mg/m3,h稳定在约98.7%,比多级雾化旋转填料床提高18.7%. 对实验数据进行回归,拟合出KGa与气相雷诺数ReG、液相韦伯数WeL和伽利略数Ga之间的关联式为     

Fe2+液相催化氧化脱除烟气中SO2

提出了一种烟气脱硫新工艺。实验选用水作脱硫剂 ,在只以Fe为催化剂的条件下进行。加入吸收液槽中的铁屑可与脱硫产生的稀硫酸进行反应 ,不仅可维持较高的吸收液pH值 ,而且产生的Fe2 + 引发了液相催化氧化SO2 反应。连续运行实验结果表明脱硫过程在不同阶段分别受SO2 溶解、Fe2 + 液相催化氧化SO2 反应、气相中SO2 扩散和铁屑与酸反应控制。吸收液中Fe2 + 质量浓度的变化和初始Fe2 + 质量浓度对脱硫率及吸收液pH值影响显示 ,可直接由清水制取高浓度硫酸亚铁溶液。实验还调查了SO2 入口质量浓度、液气比、空塔气速和吸收温度对脱硫率和吸收液pH值的影响