Process Characteristics of CO2 Absorption by Aqueous Monoethanolamine in a Microchannel Reactor

Process characteristics of CO2 absorption using aqueous monoethanolamine （MEA） in a microchannel reactor were investigated experimentally in this work. A T-type rectangular microchannel with a hydraulic diameter of 408μm was used. Operating parameters, i.e. temperature, pressure and molar ratio of MEA to CO2 were studied. Under 3 MPa pressure, the mole fraction of CO2 in gaslphase could decrease from 32.3% to 300×10-6 at least when gas hourly space velocity ranged from 14400 to 68600 h- and molar ratio of MEA to CO2 was kept at 2.2. In particular, the effects of temperature on CO2 absorption flux, mass transfer driving force, gas-liquid contact time and en- hancement factor were analyzed in detail and found that mass transfer enhancement by chemical reaction was a crucial factor for the orocess of CO9 absorotion.

Effects of Ni particle size on amination of monoethanolamine over Ni-Re/SiO_2 catalysts

Ni-Re/SiO2 catalysts with controllable Ni particle sizes(4.5–18.0 nm)were synthesized to investigate the effects of the particle size on the amination of monoethanolamine(MEA).The catalysts were characterized by various techniques and evaluated for the amination reaction in a trickle bed reactor at 170℃,8.0 MPa,and 0.5 h^-1 liquid hourly space velocity of MEA(LHSVMEA)in NH3/H2 atmosphere.The Ni-Re/SiO2 catalyst with the lowest Ni particle size(4.5 nm)exhibited the highest yield(66.4%)of the desired amines(ethylenediamine(EDA)and piperazine(PIP)).The results of the analysis show that the turnover frequency of MEA increased slightly(from 193 to 253 h^-1)as the Ni particle sizes of the Ni-Re/SiO2 catalysts increased from 4.5 to 18.0 nm.Moreover,the product distribution could be adjusted by varying the Ni particle size.The ratio of primary to secondary amines increased from 1.0 to 2.0 upon increasing the Ni particle size from 4.5 to 18.0 nm.Further analyses reveal that the Ni particle size influenced the electronic properties of surface Ni,which in turn affected the adsorption of MEA and the reaction pathway of MEA amination.Compared to those of small Ni particles,large particles possessed a higher proportion of high-coordinated terrace Ni sites and a higher surface electron density,which favored the amination of MEA and NH3 to form EDA.

Study on CO_2 Absorption by Aqueous Benzylamine and Its Formulations with Monoethanolamine as a Component for Post-Combustion Capture Process

Benzylamine(BZA) has been identified as a promising candidate for CO_2 capture process; however the evaluation of BZA in the packed column was very few. Thus, in this work, the absorption and regeneration performance of unblended BZA solvent as well as a series of amine concentrations and ratios in the formulations were studied using a semibatch bubbling reactor. And due to the formation of ivory-white precipitates in solvents containing higher BZA ratios, a 4:1 molar ratio of MEA/BZA mixed solvent was used to study its performance in a pilot-scale test bed. The results showed that a higher BZA ratio in the MEA/BZA mixed solvent resulted in a faster absorption rate, a higher mass transfer and heat transfer rate and a better cyclic performance, but the mass transfer rate of BZA decreased more quickly than MEA with the increase of CO_2 loading of the solvents. In addition, at high CO_2 loading in the MEA/ BZA mixed solvent with a molar ratio of 4:1, the ivory-white precipitates were generated which could cause blockage of the packing in the absorber, the stripper and the liquid pipelines.

Influence of monoethanolamine on thermal stability of starch in water based drilling fluid system

To improve the thermal stability of starch in water-based drilling fluid,monoethanolamine(MEA)was added,and the effect was investigated by laboratory experiment.The experimental results show that the addition of monoethanolamine(MEA)increases the apparent viscosity,plastic viscosity,dynamic shear force,and static shear force of the drilling fluid,and reduces the filtration rate of drilling fluid and thickness of mud cake apparently.By creating hydrogen bonds with starch polymer,the monoethanolamine can prevent hydrolysis of starch at high temperature.Starch,as a natural polymer,is able to improve the rheological properties and reduce filtration of drilling fluid,but it works only below 121℃.The MEA will increase the thermal stability of starch up to 160℃.There is a optimum concentration of MEA,when higher than this concentration,its effect declines.

Process simulation and analysis of carbon capture with an aqueous mixture of ionic liquid and monoethanolamine solvent

This study investigated the prospect of using aqueous mixture of 1-butylpyridinium tetrafluoroborate （[Bpy][BF4]） ionic liquid （IL） and monoethanolamine （MEA） as solvent in post-combustion CO2 capture （PCC） process. This is done by analysis of the process through modelling and simulation. In literature, reported PCC models with a mixture of IL and MEA solvent were developed using equilibrium-based mass transfer approach. In contrast, the model in this study is developed using rate-based mass transfer approach in Aspen Plus. From the results, the mixed aqueous solvent with 5-30 wt% IL and 30 wt% MEA showed 7%-9% and 12%-27% less specific regeneration energy and solvent circulation rate respectively compared to commonly used 30 wt% MEA solvent. It is concluded that the ｜L concentration （wt%） in the solvent blend have significant impact on specific regeneration energy and solvent circulation rate. This study is a starting point for further research on technical and economic analysis of PCC process with aqueous blend of IL and MEA as solvent.

Dissolution Properties of 2-(Dinitromethylene)-5-methyl-1,3-diazacyclopentane in Dimethyl Sulfoxide and N-Methyl Pyrrolidone

The molar enthalpies of dissolution for 2-（dinitromethylene）-5-methyl-1,3-diazacyclopentane（DNMDZ） in dimethyl sulfoxide（DMSO） and N-methyl pyrrolidone（NMP） were measured using an RD496-2000 Calvet microcalorimeter at 298.15 K under atmospheric pressure.Empirical formulae for the calculation of the molar enthalpies of dissolution（Δ diss H） were obtained from the experimental data of the dissolution processes of DNMDZ in DMSO or NMP.The relationships between the rate constant（k） and the molality（b） and between the reaction order（n） and the molality（b） were determined.The corresponding kinetic equations describing the two dissolution processes were dα/dt=10^-2.16（1-α） ^1.01 for the dissolution of DNMDZ in DMSO,and dα/dt=10^-2.02（1-α）^ 0.85 for the dissolution of DNMDZ in NMP,respectively.

Gamma-aminobutyric acid A receptor and N-methyl-D-aspartate receptor subunit expression in rat spiral ganglion neurons

BACKGROUND： Gamma-aminobutyric acid A （GABAA） and N-methyl-D-aspartate （NMDA） receptors are significant receptors in the central nervous system. An understanding of GABAA and NMDA receptor expression in spiral ganglion neurons （SGN） provides information for the functional role of these receptors in the auditory system. OBJECTIVE： To investigate mRNA expression of GABAA receptor （GABAAR） and NMDA receptor （NMDAR） subunits in the rat SGN. DESIGN, TIME AND SETTING： This in vitro, molecular biological study was performed at the Laboratory of Otolaryngology-Head and Neck Surgery, Guangxi Medical University, China from July 2007 to May 2008. MATERIALS： Reverse Transcriptase Kit and Taq DNA polymerase were purchased from Fermentas Burlington, ON, Canada; GABAAR and NMDAR primers were purchased from Shanghai Sangon, Shanghai, China. METHODS： SGN from 3-5 day postnatal Wistar rats was collected for primary cultures, mRNA expression of GABAAR and NMDAR subunits in the SGN was determined by reverse transcription polymerase chain reaction. MAIN OUTCOME MEASURES： Expression levels of GABAAR and NMDAR subunits were determined by quantitative analysis. RESULTS： GABAAR subunits （αl 6, β1 3, and y1 3） and NMDAR subunits （NR1, NR2A, NR2B, NR2C, NR2D, NR3A, and NR3B） were detected in the SGN. In α subunit genes of GABAAR, α1 and α3 expression was similar （P 〉 0.05） and greater than the other subunits. Of the β subunit genes, β1 subunit mRNA levels were greater than β2 and β3. Of the y subunit genes, y2 subunit mRNA levels were greater than y1 and y3. NR1 mRNA expression was the greatest of NMDAR subunits. CONCLUSION： GABAAR subunits （α1 6, β1-3, and y1-3） and NMDAR subunits （NR1, NR2A, NR2B, NR2C, NR2D, NR3A, and NR3B） were expressed in the rat SGN. Through comparison of GABAAR and NMDAR subunit expression, possible GABAAR combinations, as well as highly expressed subunit combinations, were estimated, which provided information for pharmacological and electrophysiological characteristics of GABAAR in the auditory system.

Synthesis and Structure Analysis of a Tripeptide Containing N-methyl Group Amino Acid

A convenient method of synthesizing a tripeptide-containing N-methyl group amino acid was developed using O-benzotriazole-N,N,N＇,N＇-tetramethyluronium-hexafluorophosphate as the condensing agent. The crystals of tripeptide had white needles belonging to the orthorhombic space group P2_12_12_1. The conformational preference for homochiral tripeptides with one N-methylated amide bond was also investigated. Crystal-structure analysis showed that homochiral tripeptides with an internal N-methylated amide bond preferred a trans-amide form, thereby giving the peptide β-fold characteristics. Intermolecular C-H···O and N-H···O hydrogen bonds linked the molecules into a one-dimensional chain and stabilized the structure.

RE-DISTRIBUTION OF THE N-METHYL GROUP IN GELSEMINE

The N_(b)-bromomethyl derivative (2) of gelsemine,a quaternary ammonium salt,was found to be recalcitrant toward Hofmann type alkaline degradation which has been successful in other cases.Instead,a re-distribution of the N-methyl group took place,giving rise to 3a,1,3b and 3c,in descending order of R_f values.

Identification of N-Methyl Bis(2-(Alkyloxy-Alkylphosphoryloxy)Ethyl) Amines by LC-HRMS/MS

N-Methyl bis(2-(alkyloxy-alkylphosphoryloxy)ethyl)amines, which are abbreviated as PNPs, are a series of new skeleton chemicals belonging to schedule 2.B.04 chemicals of Chemical Weapons Convention (CWC). PNPs are important markers of chemical warfare agents because they are structurally relative to both nerve agents and N-mustards. In this study, fragmentation pathways of the most characteristic fragment ions in Q-TOF mass spectrometry were proposed based on the information from accurate mass and secondary fragmentations of product ions scan experiments. Results indicated that the base ion in LC/HRMS was the quasi-molecular ion [M+H]+. In LC-HRMS/MS, it was [M+H-CnH2n+1P(O)(OH)CmH2m+1O]+ fragment ion which was formed by losing an alkyloxy alkylphosphoryloxy group from the quasi-molecular ion. The diagnostic ion m/z84.0814 was identified as [C5H10N]+, which was the group of (CH2=CH)2N+(H)CH3. PNPs have two protonated centers. One is on the N atom, the other is on the O atom (P=O). O-n-propyl PNPs generally exhibited two fragmentation pathways. Firstly, the quasi-molecular ion [M+H]+ lost a propoxy alkylphosphoryloxy group to produce [R1P(OH+)(O-n-C3H7)OCH2CH2N(CH3)CH=CH2]+, which could be fragmented further to produce [C5H10N]+ ion. Secondly, [R1P(OH+)(O-n-C3H7) OCH=CH2]+ ions were produced from [M+H]+ and fragmented further to produce the abundant ions [R1P(OH+)(OH)OCH =CH2]. However, O-isopropyl PNPs characteristically produced weak fragment ions [M+H-C3H6]+, which were presumably formed via loss of CH3CH=CH2 from [M+H]+. Other PNPs showed similar fragmentation pathways as O-n-propyl PNPs. On the summarization of the MS fragmentation pathways of PNPs, LC-HRMS/MS quantitative and qualitative methods were developed and applied to analyze N-Methyl bis(2-(butoxy-methylphosphoryloxy)ethyl]amine in high background organic samples. The analytical results had successfully supported the sample preparation for the 33rd official proficiency test of Organization for Prohibition of Chemical Weapons (OPCW).

基于MEA碳捕集过程的溶剂降解模型研究

目的吸收剂降解是工业烟气碳捕集过程中普遍存在的问题。目前,关于乙醇胺(MEA)溶剂降解的研究主要集中于单一的降解过程,缺乏对MEA溶剂降解过程完整机理模型的研究。提出了一种综合考虑MEA氧化降解和热降解的溶剂降解模型,使其能够更为准确地预测实际工业生产过程。方法建立了反应器的动态模型,并利用粒子群(PSO)算法,基于MEA溶剂降解的实验数据,构建了数据驱动的MEA溶剂降解模型。基于实际工厂数据,建立了一个包含MEA溶剂降解过程的稳态模型,并对关键设备中溶剂的降解情况进行了详细分析。在此基础之上,讨论了工艺参数对溶剂降解的影响,并提出在实际生产过程中有效降低溶剂降解的操作方法与建议。结果该模型的预测结果和实际工业生产数据较为吻合,可有效预测工业烟气碳捕集过程中MEA溶剂的降解情况,并在优化工艺操作参数方面表现出较大的潜力。结论该模型的建立可为碳捕集的模拟研究和工艺设计提供重要的参考。

化妆品中乙醇胺类的GC-MS分析

Gas chromatography-mass spectrometry (GC-MS) method has been developed for the simultaneous determination of monoethanolamine,diethanolamine,triethanolamine in cosmetics.The detected materials were extracted with ethanol by ultrasonic, then were analyzed by GC-FID and GC-MSD.The relative standard deviations (RSD) were 0.76%-3.43%,and recoveries were 85.8%-106.0%. The limit of detection was 0.05%.

低碳钢在富含H_2S乙醇胺溶液中的腐蚀及缓蚀剂抑制

利用失重、腐蚀电化学方法和表面分析技术研究了碳钢在富含H2 S的乙醇胺(MEA)溶液中的腐蚀行为,以及添加缓蚀剂后对其电化学行为的影响.讨论了IMC -C5缓蚀剂对该体系的缓蚀作用机理.结果表明,脱硫系统中吸收了硫化氢的乙醇胺溶液对碳钢的腐蚀十分严重,IMC -C5缓蚀剂能有效控制碳钢在该体系中的腐蚀,其缓蚀作用主要来自于吸附缓蚀剂分子对腐蚀阳极过程的抑制。

乙醇胺为主体的CO_2吸收剂的复配研究

以改善乙醇胺(MEA)水溶液吸收负荷、吸收速率、再生程度和防腐蚀等性能为目标,对以MEA为主体的复配吸收剂的性能进行了研究。结果表明,在MEA水溶液中加入哌嗪(PZ)或者2-氨基-2-甲基-1-丙醇(AMP)能提高MEA水溶液吸收CO2的负荷、平均吸收速率和再生性能。在溶液中加入少量氧化膜型缓蚀剂能有效抑制吸收剂溶液对碳钢的腐蚀,吸收剂溶液对碳钢的腐蚀速率从无缓蚀剂条件下的1.96 g/(m2.h)可降低到0.2 g/(m2.h)左右,极大地改善了吸收剂溶液的防腐蚀性能,对碳钢材料起到了较好的保护作用,缓蚀效果为偏钒酸钠>铬酸钾>重铬酸钾>亚硝酸钠>硝酸钠>磷酸钠>亚硫酸钠。

环丁砜对乙醇胺溶液吸收和解吸CO2的影响

利用物理溶剂环丁砜替代部分水,采用气液搅拌实验装置和真实热流量热法测定了环丁砜对乙醇胺(MEA)溶液吸收和解吸二氧化碳(CO_2)过程的影响,考察了CO_2循环负载、吸收速率、吸收热和解吸热等性质变化。研究表明:环丁砜对MEA溶液负载CO_2的吸收热影响较小,但对吸收速率、循环吸收容量和解吸过程影响较大。环丁砜可降低MEA溶液对CO_2的表观吸收速率,且随CO_2负载量的增大,降幅也逐渐变大。环丁砜有利于富液解吸过程,加快解吸速率,增大CO_2解吸程度,同时单位热流负荷、单位冷流负荷和单位能耗均有不同程度的降低。在燃煤电厂烟气条件下,20%MEA+20%sulfolane体系相对20%MEA体系,其表观吸收速率平均降低约10%,CO_2循环吸收容量增加24%,单位CO_2解吸能耗降低18%。

θ环填料塔中单乙醇胺吸收CO_2传质性能研究

在乱堆θ环不锈钢填料的自制填料塔中,使用单乙醇胺（MEA）作为吸收剂,研究MEA脱除CO2的去除率和总体积传质系数KGav,考察了贫液中CO2负载量、吸收剂浓度、液体流量、吸收温度等不同参数对总体积传质系数的影响.实验结果表明,KGav随贫液中CO2负载量的增大而减小,随吸收剂浓度、液体流量的增大而增大;且进料温度在30~50℃时,KGav随温度的增大而增大.

牛磺酸合成方法的改进

以乙醇胺为起始原料，经酯化和磺化两步反应制得牛磺酸，总收率为８３％。

钛硅分子筛催化乙醇胺合成三乙烯二胺工艺研究

在自制的小型反应器上以钛硅分子筛(TS-1)为催化剂,乙醇胺为原料,对合成三乙烯二胺工艺进行研究,考察了温度、n(H2O)/n(MEA)对反应的影响。研究结果表明,以TS-1为催化剂,温度为340℃,水/乙醇胺摩尔比为3.5,乙醇胺的转化率达90%以上,三乙烯二胺的选择性达62.57%。同时通过对反应产物的成分分析,推测了乙醇胺合成三乙烯二胺的反应机理。

胺法脱碳系统流程改进及优化模拟

采用一乙醇胺(MEA)进行燃煤电厂烟气脱碳是目前比较成熟和可行的技术,但是存在再生能耗高的严重缺陷。胺法脱碳系统流程改进及优化能有效降低再生能耗。应用Aspen Plus软件基于速率模型对传统胺法脱碳流程及其改进流程进行模拟研究。这些改进的流程包括吸收塔中间冷却流程、富液分流流程、贫液蒸汽再压缩流程、分流流程及富液分流与贫液蒸汽再压缩整合流程。研究结果表明:富液分流与贫液蒸汽再压缩整合流程节能效果最好,和传统流程相比再生能耗及等量功分别下降28.2%和11.9%。节能效果其次的是富液分流流程,再生能耗和等量功分别下降19.3%和11.8%。贫液蒸汽再压缩流程使再生能耗下降了14.1%,而等量功只下降了4.1%。吸收塔中间冷却流程和分流流程节能效果比较有限。

ZSM-5分子筛催化合成乙撑胺

研究了从单乙醇胺 (MEA)和氨合成乙撑胺。所用的催化剂为 ZSM- 5分子筛。反应条件为 :t=2 80～ 3 6 0°C,p=2 .0～ 8.0 MPa,NH3/MEA=5～ 5 0 (摩尔比 )。反应对 EDA、PIP、TEDA的选择性较高 ,MEA的转化率可达到 85 %。