Enhancement of carbon dioxide absorption into aqueous methyldiethanolamine using immobilised activators

Blends of ‘activating’ primary or secondary amines (diethanolamine, DEA) with tertiary amines, (methyldiethanolamine, MDEA) are commonly used for the removal of CO₂ from gas mixtures. To avoid undesirable side-effects from these activators, such as increased corrosion or higher energy requirements for regeneration, we propose using immobilised primary or secondary amine groups on solid supports. In this manner the activating additives can be localised to those parts of the absorption column where the high absorption rates achieved are truly beneficial and excluded elsewhere.The studies presented were carried out to provide an initial evaluation of the feasibility of this novel concept. Preliminary experiments carried out in a discontinuously operated stirred tank reactor reveal similar enhancement of the CO₂ absorption into ‘activated’ MDEA solution, when the soluble DEA additive is replaced by a suspended solid adsorbent, containing the equivalent quantity of immobilised amine groups. Further experiments examined the CO₂ absorption in a three phase fluidised bed column. They demonstrated that the immobilised activator can be employed in a continuously operated process too.All experimental results support the basic feasibility of using immobilised primary amines in place of homogeneous additives to enhance CO₂ absorption in tertiary amine solutions.     

新型萘四酰亚胺类长波长荧光染料的构建及其光谱调控

本文通过杂环胺类对二溴萘四酰亚胺的亲核反应,分别设计合成了8个未见报道的基于萘四酰亚胺母体的新型单取代或者双取代荧光染料.系统性光谱研究表明,胺类的推电子作用差异可以很好地调控其吸收和荧光波长,使之成为一类性能良好的可见或长波长荧光染料(最大吸收509—580 nm;最大发射565—638 nm;荧光量子效率0.21—0.54;Stokes位移36—77 nm).     

抗氧及摩擦改进剂的发展研究

抗氧及摩擦改进剂能够显著提高润滑油的抗氧抗磨性能,是润滑油的重要添加剂。但目前主流的抗氧及摩擦改进剂均含有对环境不利的S、P元素,开展新型环保抗氧及摩擦改进剂研究具有重要理论和实践价值。从抗氧剂和摩擦改进剂剂着手,介绍了目前使用最多的ZDDP的润滑机理和存在的局限,综合论述了酚型、胺型、无硫磷含氮杂环型抗氧剂和离子液体型、含氮杂环型、纳米粒子型摩擦改进剂的作用机理以及最新的研究成果,发现含氮杂环化合物具有成为新型抗氧摩擦改进剂的潜力,提出其存在的缺陷,并展望了未来的研究工作。     

天然气半贫液脱碳工艺三元胺液配方优选

为实现天然气脱碳工厂降本增效目标,基于某工厂PZ活化MDEA半贫液工艺,在现有设备能力下进一步提升胺液性能,进行三元复配胺液配方筛选以替代原有吸收剂。本文针对单一胺液的贫液、半贫液及富液分别进行实验,确定合适的主体胺液及添加剂,将胺液进行三元复配后通过实验探究三元复配胺液的吸收及再生性能,旨在寻找吸收容量大、吸收速率快、解吸率高、循环溶解度高、再生能耗低综合性能优的胺液配方。通过研究发现,单一胺液中AMP、DETA及PZ吸收性能较优,TEA再生能耗最低,解吸率最高;对于三元复配胺液而言,当MDEA/DEEA为主体胺液时,两种胺液配方贫液状态下的吸收速率和吸收负荷均较高,MDEA/TEA双主体胺液的最终解吸率高于MDEA/DEEA双主体胺液,TEA的加入显著提高了胺液的解吸率;筛选得到的三元高效胺液配方18%MDEA+18%TEA+4%PZ的半贫液循环溶解度高于原PZ活化MDEA配方,再生能耗较低,可代替PZ活化MDEA胺液应用于天然气半贫液脱碳工艺。     

MDEA吸收CO_2的活化剂及吸收设备研究进展

综述了近年来工业及实验研究中已出现的MDEA脱碳的活化剂。阐述了醇胺、烯胺、杂环等多种活化剂对MDEA吸收CO_2的活化性能的影响,研究显示醇胺类活化剂具有工业应用前景:从吸收装置方面介绍了旋转填料床和膜接触器两种新型设备在MDEA吸收CO_2方面情况,指出了今后研究和开发的主要方向,提出MDEA的活化剂开发应从节能、吸收机理和工业实际应用入手。     

EFFECTS OF COMPOSITION ON THE PERFORMANCE OF ALKANOLAMINE BLENDS FOR GAS SWEETENING

The use of amine blends to harness the desirable qualities of the constituent amines in order to reduce operating costs and/or improve product quality is becoming increasingly attractive to operators of alkanolamine-basedgas sweetening units. A number of parameters, all of which have economic implications, can be used to monitor the performance of amine blends. These include absorption rates, equilibrium solubility, corrosion, solution degradation and reclamation. This paper evaluates the influence of blend composition and components on some of the above parameters for aqueous blends of MDEA + MEA, MDEA + DEA and MDEA + DIPA     

苯乙烯类塑料耐老化性能研究

对纯聚苯乙烯(PS)、高抗冲聚苯乙烯(HIPS)、PS/(苯乙烯/丁二烯/苯乙烯)共聚物(SBS)共混物、添加助剂的PS和HIPS等5组试样进行紫外光加速老化。表征了5组试样老化前后的力学性能、特性粘度、分子链结构的变化。研究表明,紫外光加速老化使材料的力学性能降低,表层发生龟裂;表层的溶液粘度下降较明显,距厚度大于0.4mm时其粘度下降缓慢;傅立叶变换红外光谱谱图中在1720cm-1处出现明显的吸收峰,表明有CO生成;纯HIPS、添加助剂的HIPS和PS/SBS共混物在910、966cm-1处的吸收峰强度明显减弱,表明发生了烯烃碳碳双键的断裂,添加助剂的HIPS老化后的透过率保持率最高。     

A RIGOROUS MODEL FOR ABSORPTION OF CARBON DIOXIDE INTO AQUEOUS N-METHYLDIETHANOLAMINE SOLUTION

A rigorous model for absorption of carbon dioxide into aqueous N-methyldiethanolamine (MDEA) based on the assumption of reversible reactions and the simplified model with a pseudo-first order irreversible reaction hypothesis were employed to compare with experimental data. The experimental absorption rates were obtained from a characterized double stirred-cell absorber with a planar gas-liquid interface. It was demonstrated that the numerical solution of the rigorous model provides a better prediction for the absorption rate of carbon dioxide into aqueous MDEA solution than that of the simplified model. Only in the case of absorption experiments carried out at a low carbon dioxide partial pressure (p < 20 kpa) and low amine concentration (MDEA_total < 1000 mol/m³), the assumption of pseudo-first order irreversible reaction is reasonable.     

Electrochemical methods for the study of corrosionin lubricant additive systems

Potentiodynamic polarization has been used to study the corrosion behaviours of mild steel and copper in solutions containing some examples of common types of lubricant additives. A variety of conditions for performing of experiments were investigated. The best results were obtained in a background solution of 0.01m tetra-n-butylammonium perchlorate in 1:1 toluene/ethanol. The behaviour of the aforementioned metals was characterized and compared in solutions containing allyl amine, alkyl phosphite, and organic sulfides. For most solutions, corrosion and pitting potentials and corrosion rates of each metal were found to vary with the compound's concentration. Changes in the corrosivity of chemicals towards metals were monitored as a corrosion inhibitor was added to their solutions. The relative corrosion behaviour observed were consistent with the known performance of these metals in contact with lubricants containing these additives.     

Improvement in CO2 absorption and reduction of absorbent loss in aqueous NH3/triethanolamine/2-amino-2-methyl-1-propanol blends

Changes in the CO₂ absorption rates and capacities of the absorbent 2-amino-2-methyl-1-propanol (AMP), blended with NH₃ and other additives, were investigated toward performance improvement. The NH₃-blended absorbent removed CO₂ more efficiently than the AMP absorbent alone. However, absorbent loss through NH₃ evaporation was observed under these conditions. A second absorbent, the tertiary amine triethanolamine (TEA), which has a low vapor pressure, was selected and blended with the NH₃/AMP system to reduce NH₃ evaporation. Its effects on NH₃ loss and the absorption rate and capacity of the NH₃/AMP system were investigated, and the optimum blending ratios were determined. In addition, the absorbent blend at the optimum blending ratio was compared to AMP alone and the commercially available absorbent monoethanolamine at the same weight ratio. The thermal stabilities of the absorbents, under conditions used in the CO₂ absorption process, were compared by thermogravimetric analysis.     

Absorption of carbon dioxide into aqueous blends of 2-amino-2-methyl-1-propanol and diethanolamine

This work presents an experimental and theoretical investigation of CO₂ absorption into aqueous blends of 2-amino-2-methyl-1-propanol (AMP) and diethanolamine (DEA). The CO₂ absorption into the amine blends is described by a combined mass transfer-reaction kinetics-equilibrium model, developed according to Higbie's penetration theory. The model predictions have been found to be in good agreement with the experimental rates of absorption of CO₂ into (AMP+DEA+H₂O). The good agreement between the model predicted rates and enhancement factors and the experimental results indicate that the combined mass transfer-reaction kinetics-equilibrium model with the appropriate use of model parameters can effectively represent CO₂ mass transfer for the aqueous amine blends AMP/DEA.     

聚甲醛的耐热稳定化研究

介绍聚甲醛（POM）的热分解特征,热稳定性评价方法及各种添加剂对POM的热稳定化作用,讨论了位阻酚类抗氧剂和位阻胺类光稳定剂并用,以及添加含双键化合物或聚酰胺低聚物等改善POM热稳定性的方法。     

三乙醇胺与烯胺混合胺液脱碳性能及配比优选实验研究

胺法脱碳以其脱除效果好、能耗低等优点在天然气预处理中得到广泛应用。目前国内外普遍采用以甲基二乙醇胺为主体的复配胺液为吸收剂,为适应寻找经济、高效的新型吸收剂的需求,本文选取同为叔胺的三乙醇胺(TEA)为主体进行实验研究,在TEA反应机理的研究基础上,添加二乙烯三胺/三乙烯四胺(DETA/TETA)进行混合胺液的吸收解吸性能分析,对比优选出综合表现较好的混合胺液,考察其不同配比下吸收、解吸及贴近实际生产的循环利用效果,完成配比优选研究。结果表明:添加烯胺后,可大大提高吸收性能,但会降低解吸效果;TEA+DETA吸收和解吸性能优于TEA+TETA;TEA+DETA的优选配比为2.0/1.0和2.4/0.6;经循环实验验证,2mol/L TEA+1mol/L DETA综合效果最佳。     

耐高温及阻燃环氧树脂改性的研究进展

综述了近年来耐高温及阻燃环氧树脂改性的研究进展。目前对环氧树脂耐高温和阻燃方面的改性方法主要有硅改性,磷改性,硅、磷、胺协同改性,刚性棒状改性,芳杂环和脂环族改性,马来酰亚胺改性,氰酸酯改性,内消旋改性和有机钛改性等方法。     

Absorption of co2 into aqueous tertiary amine/mea solutions

Absorption rates for CO₂ into aqueous solutions of TEA, MDEA and blends of MEA with MDEA and TEA were measured in a stirred cell by a method similar to that used by Laddha and Danckwerts (1981). Second order rate constants for CO₂-TEA and CO₂-MDEA were obtained from the single amine data for temperatures in the range of 25-60°C. A modified pseudo first order model based on the film theory is used to predict the rate of absorption of CO₂ into mixed amine solutions. This model accounts for the variation of amine concentration in the film and assumes a shuttle mechanism for rate enhancement. Bulk liquid concentrations of the various species present are obtained from a simplified thermodynamic model. The model predicts absorption rates that are in agreement with experimental measurements.     

Rates of isotopic exchange between hydrogen and aminomethane catalyzed by potassium methylamide

Pseudo first order kinetic constants for the exchange of deuterium between hydrogen and aminomethane were determined from measurements of the rates of absorption of hydrogen deuteride into liquid aminomethane flowing over a sphere. Potassium methylamide dissolved in the amine catalyzed the reaction. Kinetic constants range from 130 to 650 sec^?1 at temperatures from —30° to —10°C and catalyst concentrations of 4.95 to 15.8 g K/kg amine.     

Evaluation of Mass Transfer Enhancement by Additives Using a New Semi-Empirical Method Based on Surface Tension Gradients and Marangoni Numbers

The use of additives is a viable strategy for enhancing absorption rates and, thereby, increasing the capacity of absorption machines. However, there is no general consensus or standard procedure in selecting potential additives. In this paper, we propose a new semi-empirical approach for the evaluation of mass transfer additives using surface tension gradients and Marangoni numbers. An analytical evaluation of surface tension has been carried out for ranges of temperature and LiBr and additive concentrations.     

ABSORPTION OF CARBON DIOXIDE INTO AQUEOUS DIETHANOLAMINE SOLUTIONS

The rates of absorption of pure carbon dioxide into aqueous diethanolamine solutions were measured at 25^°C in a liquid-jet column and a wetted-wall column. Experimental results were analyzed with the chemical absorption theory based on the penetration model. Physical solubility of carbon dioxide in aqueous diethanolamine solutions was determined from the absorption rates measured in a near pseudo first-order reaction regime and was found to show a salting-out effect. The measured absorption rates were in good agreement with the theoretical predictions for gas absorption with an irreversible third-order reaction.     

含氮杂环的酯或酰胺类衍生物的制备及其摩擦学性能

设计合成了4种含氮杂环的酯或酰胺类衍生物润滑油添加剂（Ⅰ~Ⅳ）。采用核磁共振氢谱（¹H NMR）和飞行时间质谱（MALDI-TOF-MS）对所得产物的结构进行了表征;研究了4种添加剂的油溶性、热稳定性和抗腐蚀性;在四球摩擦磨损试验机上系统考察了添加剂在液体石蜡中的摩擦学性能;利用扫描电子显微镜（SEM）和能谱分析仪（EDS）观察和分析了钢球磨斑的表面形貌和元素组成。结果表明,4种添加剂均具有良好的油溶性、热稳定性和抗腐蚀性,当添加剂Ⅰ的质量分数达到1.0%时,钢球的磨斑直径（WSD）和摩擦系数分别比在液体石蜡中降低了33%和26%。SEM结果显示4种添加剂的加入能明显减小WSD,减少表面磨损,EDS结果表明添加剂在摩擦过程中形成了复杂的反应膜。     

Synergistic effect between hindered amine light stabilizers and partially hindered oligomeric amines in polyethylene

The synergistic effect between novel synthesized oligomeric amines and a commercial hindered amine light stabilizer (Chimassorb 944) was studied in medium‐density polyethylene (MDPE). Mixtures of the synthesized oligomeric amines and commercial additives were prepared at different concentrations and then were evaluated by ultraviolet and thermal aging. The evaluation was carried out on films prepared by compression molding, and the oxidation rates were monitored with Fourier transform infrared, which was used to measure the formation of different functional groups: carbonyl, vinylic, and hydroperoxide. The data showed that, independently of the concentration of the commercial additives, when they were combined with oligomeric amines, they produced a synergistic effect with a magnitude depending on the MDPE aging conditions and the additive concentrations. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 280–287, 2004