Purification of Lactic Acid by Heterogeneous Catalytic Distillation Using Ion-exchange Resins

The purification of lactic acid based on the esterification of raw lactic acid from fermentation broth and then the catalytic distillation hydrolysis of methyl lactate simultaneously to achieve pure lactic acid is reported. The esterification kinetics of lactic acid with methanol catalyzed by strong-acid cation-exchange resins (Amberlyst-15,D001, D002, NKC, 002) was studied under the condition that simulates the real catalytic environment. Experimental results were correlated by a Langmuir-Hinselwood model and the nonideality of the solution was taken into account by using activities calculated by the universal quasichemical functional group activity coefficient (UNIFAC) method.A good agreement between the model and the experimental data was achieved. Continuous purification experiments were conducted to find the optimum column configuration and operation condition for the system. The effects of various parameters, e.g. the length of different section of the column, feed rate and ratio of reactants, packing material and catalyst type, were studied. This novel system shows good separation results in lab scale, and is potential for industrial application.

Tungsten removal from molybdate solutions using chelating ion-exchange resin:Equilibrium adsorption isotherm and kinetics

The equilibrium adsorption isotherm and kinetic of the sorption process for W and Mo on macro chelating resin D403 were investigated on single Na2 Mo O4 and Na2WO4 solutions.The sorption isotherm results show that the adsorption process of W obeys the Freundlich model very well whereas the exchange process with Mo approximately follows the Henry model.The kinetic experiments show that the intraparticle diffusion process was the rate-determining step for W sorption on the resin,and the corresponding activation energy is calculated to be 21.976 k J/mol.

Investigation of the Ion-Exchange Behavior of Zeolite Y in the Presence of Resin

Ion-exchange process of zeolite Y using ammonium-type resin as an exchange reagent was successfully carried out. The effect of temperature, space velocity and ion concentration on the breakthrough curves was carefully investigated. At the first exchange section, the maximum proportion of qualified zeolites(QR) was obtained at a temperature of 70 ℃, a weight hourly space velocity of 0.61 h-1, and an ion concentration of 197 mg/L. The minimum length of mass-transfer zone(MTZ) of the resin bed was achieved at a temperature of 70 ℃, a space velocity of 0.61 h-1, and an ion concentration of 423 mg/L. At the second exchange section, the length of MTZ of the resin bed was significantly increased, and the exchange of Na+ ions contained in zeolite Y was more difficult than that achieved at the first exchange section. In both the first and the second exchange sections, the zeolite Y subjected to ion exchange with the resin maintained the similar physical and chemical properties as compared to those exchanged by the conventional approaches, but the zeolite Y, which was obtained after ion exchange, contained a significantly lower content of Na2 O.

The Desalting Property of Ion-Exchange Resins in Organic Solvent

the desalting property of ion-exchange resins in organic solventis reported by using potassium acetate as a model compound. Theexperimental results show that solvability of the solvent, stirringspeed, and temperature are the factors which influence theion-exchange rate. The increase of solvability, stirring speed andtemperature will speed up the ion-exchange process.

Study on the Stability of Ion-exchange Resin Catalysts:Ⅰ. TGA as a Rapid Evaluating Method

The thermal stability of five commercial ion-exchange resin catalysts was studied by means of thermal gravimetric analysis （TGA） at elevated temperatures of up to 600℃ and isothermal temperatures in the range of 150℃ and 200 ℃. Resin samples with different initial water contents were also investigated. The study indicated that TGA, as a complementary evaluating method for the plug flow reactor system approach, could be used as a fast analyzing means for study on the thermal stability of ion-exchange resin catalysts. The stoichiometric calculation of the isothermally treated resin catalysts based on the FTIR analysis and acid capacity confirmed that the weight loss of the resins at 150℃ and 200℃ was caused by the desulfonation process and that desulfonation occurred mainly at the para-position of the benzene ring in the resins. H＋ ions and moisture played an important role in the desulfonation process.

Study on Stability of Ion-exchange Resin Catalysts:Ⅱ. Desulfonation during Isobutylene Dimerization

The performance of ion-exchange resin catalysts during isobutene (IB) dimerization was investigated under different IB contents,temperatures and liquid-volume hourly space velocity (LHSV) using a plug flow reactor in the absence of any selectivity enhancing component.High IB content and temperature resulted in a high conversion and C12 selectivity bu low C8 selectivity.The influence of LHSV was related with the IB content:LHSV had great effect at high IB content,while the performance of ion-exchange resin changed little with LHSV if IB content was low.The effect of water on the stability of resins was also studied.Desulfonation was observed during the C4 dimerization reaction when water was added to the feed.Chlorinated resin was more stable than conventional polystyrene-based resins during the test.

螯合树脂塔再生废水回收工艺改进

优化了螯合树脂塔再生废水回收工艺:将酸性废水送至脱氯塔与淡盐水混合,淡盐水脱氯后,被送至盐水工序用于化盐;将碱性废水直接送至盐水工序用于化盐.工艺优化后,实现了酸性废水和碱性废水的高效回收利用.

二次盐水精制工序技术改造

对二次盐水精制工序螯合树脂塔再生过程中酸、碱加入量和加入方式以及再生废水的回收方式进行了改造,年增效190万元。

八层浆料汽提塔运行总结

介绍了八层浆料汽提塔的结构、设计参数及工作原理,分析了八层浆料汽提塔在运行过程中的影响因素,并进行了技术改进,从而提升了八层浆料汽提塔的运行效能。

500 kV直线塔复合绝缘子断串原因分析

运用外观检查、解剖检查、染料渗透试验、红外测温试验,对一起500 kV某线路72号直线塔复合绝缘子断串故障原因进行分析。结果表明,故障相绝缘子护套存在自身缺陷、密封不严等问题,导致其芯棒与外界空气、雨水等接触,在强电场、酸液、潮湿空气等长期作用下芯棒受腐蚀,进而造成复合绝缘子中承力作用的玻璃纤维在电化反应下断裂,绝缘子在导线自重等综合作用下断串。

全卤制碱中储卤池盐泥的处理

针对在全卤制碱中采输卤工序储卤池、淡盐水池的盐泥沉积问题,提出了处理方案,达到了预期效果。

某电厂凝结水精处理再生装置问题分析及处理措施

某电厂凝结水精处理再生装置采用高塔分离再生工艺,在调试过程中出现了树脂从再生塔泄漏至树脂捕捉器内,以及阴阳树脂分离不够彻底、管道堵塞的问题.文章对于树脂泄漏、分离不彻底及管道堵塞的原因进行了排查与分析,最终确定了事故原因并提出了相应的解决方案,为精处理系统高速混床的调试运行顺利进行奠定了基础.

氯碱生产系统仪表及自控阀异常的分析及处置

针对烧碱装置运行过程中自控系统仪表及自控阀出现的问题,进行了分析,并给出解决措施。

Treatment of drilling wastewater using a weakly basic resin

Macroporous weak basic anion exchanger （D301R） was used to remove organic substances from drilling wastewater. The effect of pH, temperature and contact time on adsorption behavior was investigated in batch experiments, which indicated that the COD （Chemical Oxygen Demand） removal ratio of drilling wastewater was approximately 90%, and the COD of treated wastewater was below 70 mg/L under appropriate operating conditions. A mixed liquor of NaOH and NaCI was selected as desorbent because of its better elution performance. The results of column dynamic adsorption and regeneration showed that the COD of wastewater could be efficiently removed by D301R resin, and the resin was easily regenerated by the selected desorbent.

ADSORPTION OF HUMIC SUBSTANCES BY MACRO WEAKLY BASIC IONEXCHANGE RESIN AND THEIR EFFECTS ON REMOVAL OF Cu^(2+) AND Pb^(2+)

Adsorption of humic, tannic and gallic acids by a macro weakly basic ion-exchange resin JN-01 was studied. The adsorption capacity of this resin for gallic and tannic acids is much higher than that for humic acid, which can be explained on the basis of both their molecular size and ionization degree. Furthermore, humic acid is separated into different components with molecular weight in the range from 2000 Da to 100000 Da by ultra-filter, and their adsorption isotherms on resin JN-01 indicate that humic acid＇s molecular weight is an important factor which makes significant influence on adsorption. Finally, changes in the amount of Cu^2＋ and Pb^2＋ adsorbed on resin JN-01 as a function of the concentration of each of these three acids were studied. A large increase in the heavy metal ions uptake is observed in the presence of humic substance, such advantages are due to the interactions between the heavy metal ions and the unbound functional groups of the adsorbed organic acids.

INTERACTION MECHANISM OF ORGANIC MATTER WITH GEL TYPE POLYSTYRENE STRONGLY BASIC ANION EXCHANGE RESIN AND REGENERATION OF THE ORGANISM FOULED RESIN Ⅰ.The interreaction mechanism between strongly basic anion exchange resin and organic matter

It was generally considered that contamination of the gel type polystyrenestrong basic anion exchange resin by organic matter in natural water is the result ofion exchange and Van der waal's adsorption on it. On the basis of laboratory and industrial experiments, this paper confirmed that the interreaction between organicmatter and resin polymer matrix is primarily controled by a Van der waal's adsorption.

A STUDY ON THE KINETICS OF EXCHANGE REACTIONS OF W（Ⅵ） OR Mo（Ⅵ） WITHIN MACROPOROUS ANION EXCHANGE RESIN（D290） PHASE

The exchange behaviors of WO_4￣(2-) MoO_4￣(2-), H_2 W_(12) O_(40)￣(6-) and Mo8 O_(26)￣(4-) anions within macrOPorous exchange resin (D290) phases have been studied.The values of diffusion constant (B), inner diffusion coefficient (D), retarted time (td) half - exchange-period (t1/2), and activation energy (△E) were found from the kinetic analyses. A new method to separate W(Ⅵ) and Mo (Ⅵ) from each other was also suggested.

基于载铀树脂饱和再吸附-淋洗一体化工艺的U型塔设计研究

针对部分酸法地浸铀矿工艺在浸出中后期存在的浸出液铀浓度偏低、HSO_(4)^(-)离子竞争吸附、吸附饱和树脂容量低、固定床淋洗合格液铀浓度低等问题,设计了一种离子交换设备U型塔,研究了采用饱和再吸附与淋洗一体化工艺处理载铀树脂,考察了处理后淋洗液中铀浓度的变化。结果表明:经U型塔一体化工艺处理后,淋洗合格液中铀质量浓度升至43~50 g/L;U型塔运行稳定,树脂运移顺畅,塔内铀浓度梯度分布合理。该设备适用于地浸采铀浸出液处理过程,有一定的推广应用价值。

零手动操作系统在460 kt/a离子膜烧碱装置的应用

为提升某460 kt/a离子膜烧碱装置的自动化水平,稳定产品品质、降低能耗物耗,结合精良装备改造、完善基础自动化改造,开发了离子膜烧碱装置全流程、全过程无人控制的零手动操作系统。实际应用结果表明,DCS操作量降低到0次;关键控制指标(液碱含量、电解槽温度)的标准方差降低了40.00%以上,一期~四期碱液的NaOH的质量分数分别降低0.29%、0.32%、0.38%、0.02%,平均降低0.26%;树脂塔每月可减少再生约4次,每月减少消耗纯水690 m3、盐酸12 m3和液碱10.52 m3。整个装置每年可实现节能降耗创造的经济效益约为277.65万元。不仅装置自动化水平显著提升,还实现了增产增效、节能降耗。

改性玄武岩鳞片在氟碳重防腐涂料中的应用

为解决海上风电金属塔筒的腐蚀问题,使用硅烷偶联剂KH550对玄武岩鳞片进行改性,以氟碳树脂为成膜物质,制备了不同改性玄武岩鳞片含量的氟碳重防腐涂料。采用扫描电镜(SEM)、红外光谱(FT-IR)、X射线衍射(XRD)对制备的样品进行了表征,利用电化学阻抗谱(EIS)、酸碱浸泡试验、中性盐雾试验和大气曝晒试验等评价了涂层性能。结果表明:加入6%的改性玄武岩鳞片的涂层综合性能最优,其附着力可达1级,硬度高(4H),固化快,表干时间仅20 min,一次成膜厚度平均可达100μm以上,耐化学品性优异,具有长效防腐耐候性。