强化结晶氨法脱碳实验研究

针对目前氨法二氧化碳捕集技术中存在的氨逃逸、再生能耗高、反应后期吸收率低等问题提出了强化结晶氨法捕碳工艺,采用氨水乙醇组成的混合吸收液,利用半连续鼓泡反应系统研究了实验过程中吸收液组成、吸收温度、烟气流量及烟气中CO_2体积分数对吸收及结晶规律的影响。实验结果表明,混合吸收液中选用高比例乙醇、较低的吸收温度、较高的烟气流量以及较大的CO_2体积分数有利于吸收液中晶体出现时间提前,有利于强化结晶过程,晶体含氨量占初始氨总量的分数可达38.75%,并且混合吸收液的CO_2吸收能力较纯氨水工况明显提高。创新之处在于:提出了一种强化结晶氨法捕碳工艺,对氨水乙醇混合吸收液的吸收及结晶规律进行研究,给出了能够改善吸收效果并利于结晶过程的有利工况。为接下来新工艺的进一步研究提供基础数据和参考。

潮间带沉积物中酸可挥发性硫化物提取方法的优化研究

沉积物中酸可挥发性硫化物(AVS)对某些重金属(如Cd、Pb等)的生物有效性具有强烈影响,因此沉积物中的AVS已成为水环境中重金属研究和质量评价的热点。通过改变实验装置,对实验中的吸收液、N2流量、反应酸量、水浴温度和反应时间进行对比研究且作出了优化选择,并利用优化方法分析了渤海湾天津段潮间带沉积物中AVS的含量。结果表明:(1)潮间带沉积物中AVS提取的最佳条件:以NaOH-乙二胺四乙酸-三乙醇胺混合吸收液为吸收液,N2流量为80 cm3/min,加入20 mL 1 mol/L HCl,100℃沸水浴中反应40 min。(2)大规模围海造地,已对化学指标产生影响。AVS在控制沉积物间隙水系统中重金属的分配和沉积物中重金属的化学活动性、生物可利用性方面起重要作用,应该要有足够的重视。

Absorption of Sulphur Dioxide with Sodium Citrate Buffer Solution in a Rotating Packed Bed

Absorption of SO2 from a SO2/air mixture with sodium citrate buffer solution was investigated using a rotating packed bed(RPB) in laboratory scale.The effects of operating parameters,such as the rotation speed of RPB,liquid-gas ratio,inlet gas flow rate,inlet concentration of SO2 in flue gas,sodium citrate buffer concentration and initial pH of absorption solution,on the SO2 concentration in the absorption solution or removal efficiency of SO2 were examined.Incremental rate of sulfate radical ions in the absorption solution was also examined.Experimental results indicate that the efficiency of this regenerative process will be improved by using RPB under appropriate operating conditions,and the generation of SO2-4 will be restrained in the process in RPB.

The effect of membrane pores wettability on CO_2 removal from CO_2/CH_4 gaseous mixture using NaOH, MEA and TEA liquid absorbents in hollow fiber membrane contactor

The present paper renders a modeling and a 2D numerical simulation for the removal of CO_2from CO_2/CH_4gaseous stream utilizing sodium hydroxide(NaOH),monoethanolamine(MEA)and triethanolamine(TEA)liquid absorbents inside the hollow fiber membrane contactor.Counter-current arrangement of absorbing agents and CO_2/CH_4gaseous mixture flows are implemented in the modeling and numerical simulation.Non-wetting and partial wetting modes of operation are considered where in the partial wetting mode,CO_2/CH_4gaseous mixture and liquid absorbents fill the membrane pores.The deteriorated removal of CO_2in the partial wetting mode of operation is mainly due to the mass transfer resistance imposed by the liquid in the pores of membrane.The validation of numerical simulation is done based on the comparison of simulation results of CO_2removal using Na OH and experimental data under non-wetting mode of operation.The comparison illustrates a desirable agreement with an average deviation of less than 5%.According to the results,MEA provides higher efficiency for CO_2removal in comparison with the other liquid absorbents.The order for CO_2removal performance is MEAN Na OHN TEA.The influence of non-wetting and partial wetting modes of operation on CO_2removal are evaluated in this article as one of the novelties.Besides,the percentage of CO_2sequestration as a function of gas velocity for various percentages of membrane pores wetting ranging from 0(non-wetting mode of operation)to 100%(complete wetting mode of operation)is studied in this research paper,which can be proposed as the other novelty.The results indicate that increase in some operational parameters such as module length,membrane porosity and absorbents concentration encourage the removal percentage of CO_2from CO_2/CH_4gaseous mixture while increasing in membrane tortuosity,gas velocity and initial CO_2concentration has unfavorable influence on the separation efficiency of CO_2.

Absorption Rate of CO_2 into MDEA Aqueous Solution Blended with Piperazine and Diethanolanline

Absorption rate of CO2 into aqueous solution of N-methyldiethanolamine (MDEA) blended with diethanolamine (DEA) and piperazine (PZ) was studied and a kinetic model was established. It is shown that homogeneous activation mechanism could explain this absorption process. The absorption rate coefficients of carbon dioxide into MDEA aqueous solution blended with DEA, PZ or DEA+PZ were compared with each other. The results demonstrated that the different activation effect of DEA, PZ and DEA+PZ on the carbon dioxide absorption comes from the difference in CO2 combination rate, transport of PZ and DEA to MDEA and the regeneration rate of PZ and DEA.

Study on Absorption and Regeneration Performance of Novel Hybrid Solutions for CO_2 Capture

Recently, a kind of hybrid solution MEA-methanol shows a better CO_2 capture performance over aqueous MEA solution. However, the vaporization of methanol is the biggest disadvantage that hinders its application, so it is necessary to minimize the vaporization of methanol during both the absorption and regeneration processes. In this work, two kinds of hybrid solutions were studied and compared with aqueous MEA solution and MEA-methanol solution, including MEA/TEA/methanol solution and MEA/glycerol/methanol solution. The absorption property of MEA/glycerol/methanol solution is better than aqueous MEA solution within a certain period of time and the absorption property of MEA/TEA/methanol solution is too poor to be used in CO_2 capture. By increasing the concentration of TEA and decreasing the concentration of MEA, the absorption rate, CO_2 capture efficiency and absorption capacity all decreased. Upon adding glycerol, the cyclic capacity decreased and the generation temperature increased, and moreover, the density and viscosity also increased considerably. So after adding TEA and glycerol, the CO_2 capture performance of MEAmethanol solvent cannot be improved.

Effect of Inoculants Mixture on Nutrient Uptake and Growth in Cucumber(Cucumis sativus L. ) Seedlings

[Objective]we checked the role of various proportion of three growth promoting bacteria to determine the optimum proportion with greater symbiosis in cucumber seedlings. [Method]Three strains of Rhodopseudomonas palustrisSH2,Bacillus megateriumSHⅡ3,Bacillus mucilaginosusSH1 were applied in this study. Cucumber were cultured in plastic pot,inoculating mixture with seven different proportion for 28 days. [Result]2:1:2 treatment had the strongest effect on N,P,K uptake and concentrations in the soils,on increasing enrich of Fe and Zn inroots and shoots and on plant height,stem diameter,dry weight,relative chlorophyll contents. Treatments of 1:1:2 and 1:1:1 were following ,while the weakest effect was given by 1:2:2,2:2:1 and 1:2:1 treatments. [Conclusion]2:1:2 is the optimum proportion of the three bacteria for nutrition uptake and growth of cucumber seedlings.