苯和二甲苯体系固液相平衡的数据预测与相图

针对对二甲苯装置结晶单元中由苯和二甲苯组成的相关体系,选取了固液相平衡计算模型—Van′t Hoff方程简式,利用与苯和二甲苯有关的二元和三元体系固液相平衡文献数据对该模型进行考察,利用该模型预测由苯和二甲苯组成的二元和三元体系的固液相平衡数据,并绘制三元体系的固液相平衡相图。结果表明：采用Van′t Hoff方程简式计算,苯和二甲苯有关体系的液相摩尔分数的平均相对偏差为2.69%,低共熔点温度的偏差最高为0.59℃,最低为0.01℃,表明所选模型适用于由苯和二甲苯组成的体系固液相平衡计算;利用该模型预测苯-间二甲苯、苯-邻二甲苯二元体系及对二甲苯-间二甲苯-苯、对二甲苯-邻二甲苯-苯、间二甲苯-邻二甲苯-苯三元体系的固液相平衡数据,绘制了对二甲苯-间二甲苯-苯三元体系的固液相平衡相图,这些新的相平衡数据和相图均未见有文献报道,可为对二甲苯结晶相关体系的固液相平衡研究提供理论指导和依据。     

复合萃取剂-磷酸-水三元体系液液相平衡研究

研究了复合萃取剂-磷酸-水三元体系在25℃下的液液相平衡关系,绘制了三角相图,用Hand公式对相平衡数据进行了关联。考察了不同温度条件下磷酸分配系数随原料酸中磷酸含量的变化关系,结果表明磷酸的分配系数随温度变化不大;同时,研究了磷酸中钙镁离子在两相中的分配情况,结果表明复合萃取剂对离子具有很好的选择性。     

正丁醇-异丁醇-水体系液-液-汽相平衡的研究(一)

本文测定了正丁醇-异丁醇-水三元体系沸点下液-液相平衡和汽-液相平衡数据。并用Mitsuyasu[5]的修正Wilson方程对所测数据统一进行了关联。     

甲苯和二甲苯体系固液平衡相图及其低共熔点对比

针对对二甲苯结晶相关由甲苯和二甲苯组成的二元和三元体系,选取固液相平衡计算模型—Van′t Hoff方程简式计算了由甲苯和二甲苯组成的二元和三元体系的液相摩尔分数与低共熔点温度及组成,并绘制了与甲苯有关的对二甲苯-甲苯-邻二甲苯、邻二甲苯-甲苯-间二甲苯、对二甲苯-甲苯-间二甲苯等3个三元体系的固液相平衡相图,对比分析...     

醋酸异丙酯-醋酸-水体系汽液相平衡研究

用改进的Rose釜测定了101.33 kPa下醋酸异丙酯-醋酸、醋酸异丙酯-醋酸-水(互溶区内)的等压汽液相平衡数据.考虑了醋酸在汽相中的缔合效应和非理想性,用NRTL、UNIQUAC模型对醋酸异丙酯-醋酸体系汽液相平衡数据进行关联,得到了相应的模型参数.在三元汽液相平衡数据的预测过程中详细讨论了醋酸-水体系汽液平衡数据对预测结果的影响,获得了较优的预测结果.     

水-醋酸-二异丙醚三元体系液液相平衡数据的测定

实验测定了水-醋酸-二异丙醚三元体系在293.15 K、303.15 K的液液相平衡数据.分别采用Othmer-Tobias和Bachman方程对实验数据进行了可靠性检验,相关性系数均大于0.983.绘制了三元液液平衡相图.     

醋酸甲酯-甲醇-水三元物系液液平衡数据的测定与关联

测定了常压下20、30、40、50℃时醋酸甲酯 水二元体系及醋酸甲酯 甲醇 水三元体系的液液平衡(LLE)数据,并与文献中已有的醋酸甲酯 水的液液平衡数据进行比较,证明了测定方法的可靠性。采用二元与三元液液平衡数据相结合的关联方法,并用NRTL和UNIQUAC模型对所测数据进行了热力学关联,得出了相应的模型参数。用该模型对三元体系进行计算,结果令人满意。用VisualBasic6.0语言开发了液液相平衡关联软件,可方便地用于二元和三元液液相平衡的计算。     

丁酮肟-水-异辛醇物系液液相平衡的研究

在甲基三丁酮肟基硅烷的生产过程中会产生部分含丁酮肟的废水,用萃取方法可回收丁酮肟。为获得萃取工艺所需的基础数据,在常压、60℃温度下,以工业实际废水为物料,进行液液相平衡实验,用拟三元方法处理丁酮肟-水-异辛醇三元体系的液液相平衡数据,获得了三元体系平衡相图。实验数据用非随机两相液体(NRTL)模型进行了关联,得出了该三元体系的NRTL模型参数。将实验数据与关联结果进行比较,结果表明,NRTL模型能对该三元体系进行较准确的关联。     

醋酸-甲酸-水三元体系汽液相平衡的研究

一、前言关于醋酸-甲酸-水三元体系汽液相平衡数据的报导未见有醋酸高浓区数据笔者曾报导过这三元系的数据,为了改进分析方法和考核两种模型对数据的处理,笔者对此三元系汽液相平衡数据着重高浓区重新进行了测定。     

聚甲氧基二甲醚+水+正己烷三元体系的液液相平衡

聚甲氧基二甲醚(PODEn)是一种极具应用前景的清洁柴油调和组分。研究了293.15 K、常压下PODE_1+水+正己烷、PODE_2+水+正己烷、PODE_3+水+正己烷、PODE_4+水+正己烷这4组三元体系的液液相平衡。PODE_(1-4)组分的萃取选择性系数S远大于1,表明正己烷作为萃取剂从水溶液中萃取PODE_(1-4)是可行的;经Hand结线关联检验,各体系的相平衡数据具有较高的一致性;采用NRTL和UNIQUAC热力学模型对相平衡数据进行拟合,均方根差计算(RMSD)结果和三元相图分析结果表明NRTL和UNIQUAC都能较好地描述三元体系的液液相平衡。     

杂质对磷酸萃取过程的影响

研究萃取相比与磷酸萃取率和杂质分离系数之间的关系,考察硫酸和铁2种杂质对磷酸萃取率的影响。实验结果表明:随着相比提高,磷酸萃取率上升,且各杂质分离系数提高;硫酸的存在有利于磷酸萃取,且存在一个最佳含量,使磷酸对硫酸分离系数最大;而铁离子的存在则不利于磷酸萃取。     

湿法磷酸中有机物的脱除方法

湿法磷酸中含有多种杂质,有机杂质是其中的一种。介绍了采用活性炭和化学氧化相结合脱除湿法磷酸中有机杂质的方法,分别研究了试剂用量、反应温度、反应时间和搅拌速度对脱除湿法磷酸中有机杂质的影响。结果表明,采用活性炭吸附和化学氧化相结合的方法脱除湿法磷酸中的有机杂质,最显著的影响因素为活性炭用量和双氧水用量;在最佳工艺条件下,该法可以脱除湿法磷酸中80.2%的有机杂质,净化后磷酸中残余的有机杂质含量低于食品级磷酸对有机杂质所要求的含量。该方法是脱除湿法磷酸中有机杂质的有效方法。     

正辛醇+煤油混合溶剂萃取净化湿法磷酸工艺研究

选用新型高效萃取体系正辛醇+煤油混合溶剂,研究了正辛醇+煤油混合溶剂在萃取净化湿法磷酸过程中萃取温度和相比（萃取剂与磷酸的体积比）与磷酸萃取率和杂质分离系数之间的关系, 考察了硫酸和铁两种杂质对磷酸萃取率和分配比的影响。实验表明: 随着相比提高, 磷酸萃取率上升, 各杂质分离系数提高。提高萃取温度和增加铁含量会使磷酸萃取率和分配比呈减小趋势,硫酸的存在有利于磷酸萃取。通过对正辛醇+煤油体系萃取湿法磷酸系统性的基础工艺研究,以期为设计工业化应用路线提供理论和技术支持。     

熔融悬浮结晶法提纯湿法磷酸

使用熔融悬浮结晶法分离提纯湿法磷酸,研究了全回流稳态操作条件下重力洗涤塔内磷酸的纯化过程,考察了原料质量分数、洗涤塔中搅拌转速等操作条件对塔中产品纯度、杂质质量分数沿塔高分布的影响,并用发汗提纯模型进行了拟合。研究结果表明:采用的悬浮结晶装置对湿法磷酸有良好的分离提纯效果;结晶器进料质量分数、洗涤塔搅拌速率对熔融液中杂质质量分数沿塔高的分布有很大影响,进料质量分数增加,则产品纯度增加,适度的搅拌有助于保证洗涤塔的纯化效率,而过高的搅拌速率对分离提纯效果影响不大。在结晶器H3PO4进料质量分数为84%—86%、洗涤塔搅拌速率为10—20 r/min范围内,产品磷酸纯度可达到食品添加剂的标准,发汗提纯模型能很好地描述稳态操作时塔内的杂质质量分数分布规律,在半对数坐标中,杂质质量分数沿塔高呈线性分布。     

PURIFICATION OF WET PROCESS PHOSPHORIC ACID BY EXTRACTION WITH 3-PENTANONE. STUDY OF THE IMPURITIES DISTRIBUTION. COMMENTS ON THE PURIFICATION BEHAVIOR OF DIFFERENT SOLVENTS

Abstract

3-Pentanone (DEK.) is used in this work for the purification of wet process phosphoric acid (WPA) by extraction. The study of impurities (Fe, Al, Mg, SO₄ ⁼ and F^¯ ) distribution between the conjugated phases generated shows that DFY. is very similar to isoamyl alcohol (iA) regarding its purification behavior. A review of the purification capability of all the solvents studied before is also presented. We have found a relation between the total impurities extracted and the amount of water plus phosphoric acid present in the organic phase. This relation would allow to predict the purification behavior of any solvent just from the data for the pure components.     

乳化液膜法脱除磷酸中镉的研究

镉是磷酸中的有害杂质之一,其对环境的污染和对人体的毒害日趋严重,所以必须控制磷酸中镉等有害杂质的含量。用乳化液膜法除去磷酸中的镉,采用单因素实验法,重点考察了表面活性剂Span-80,T151,T154及用量、萃取剂TBP,P204及用量、萃取时间对脱除磷酸中镉的影响。结果显示：表面活性剂T154用量为2.0 mL及萃取剂P204用量为2.0 mL时,乳化液膜具有较好的稳定性,且萃取时间为15 min时,从磷酸中除镉的效果最优。     

Purification process of phosphoric acid by vertical zone‐melting technique

The efficiency of vertical zone‐melting technique as a function of molten‐zone length, number of zone passes, molten‐zone velocity and phosphoric acid concentration on the purification process of phosphoric acid is studied. The results showed that adopting a relatively long molten‐zone length in the initial passes to effect a rapid movement of impurities and a short molten‐zone length in the later passes to obtain greater purification; additional zone‐passes cannot be made as impurities redistribution approaches limiting distribution; for stirring mechanism is not adopted in the present study and as diffusion is the only mixing process, slow molten‐zone velocity 3–6 mm h^?1 is better; the purification efficiency increases with phosphoric acid concentration, and 94–99.8% concentration of phosphoric acid is better. © 2012 Canadian Society for Chemical Engineering     

Production of phosphoric acid with low content of impurities

The present work is to study the possibility for controlled distribution of the impurities when they are decomposed by sulphuric acid to wet phosphoric acid and phosphogypsum, as well as generating technological conditions for production of clean wet phosphoric acid and its derivatives - phosphoric fertilizers, food phosphates and other phosphoric products.A coefficient of distribution D_A is introduced as a general criterion for elements dispersion. The study includes relationships between the weight ratio sulphuric acid/natural phosphate and D_A; the period of decomposition and D_A; the particle's size content of the natural phosphate and D_A. The obtained experimental data and relationships about the influence of the above discussed technological parameters on dispersion of more than 23 elements allow for control of that process in wet phosphoric acid and phosphogypsum by selecting specific technological conditions. Thus, depending on the requirements of acid's consumers and procedures for secondary processing of phosphogypsum to end-products, a selective decomposition of the natural phosphates to phosphoric acid and phosphogypsum can be carried out with content of the impurities in those products varying in narrow limits.     

浓缩湿法磷酸中的杂质对其流变性能的影响

浓缩湿法磷酸中存在大量的杂质离子,它们对浓缩磷酸的黏度和密度有着交互影响。通过模拟浓缩磷酸的组成,采用三因素二次回归正交设计的方法来考察Fe,Mg,Al等杂质离子对磷酸黏度的影响。结果表明:当杂质相对质量分数小于3.1%时Al对浓缩磷酸黏度影响最大,当杂质相对质量分数大于3.1%时,Mg对浓缩磷酸黏度影响最大;并得出杂质质量分数与磷酸黏度关系的数学模型,模型检验所得误差为7.37%,对实现浓缩湿法磷酸的管道输送提供一定参考价值。     

Utilization of spent petrochemical sulfuric acid in the production of wet‐process phosphoric acid

The possibility of the application of spent sulfuric acid from the petrochemical industry in wet‐process phosphoric acid technology was investigated. The effect of organic impurities in sulfuric acid from benzol acidic refining on the solubility of calcium sulfate hydrates is discussed. Solubility isotherms and regression equations for CaSO₄–H₃PO₄–H₂SO₄–H₂O (pure and containing impurities) systems are presented. Phase transition temperatures between dihydrate and hemihydrate calcium sulfate were determined. The difference between pure and polluted sulfuric acid systems observed is negligible over the range of typical wet‐process phosphoric acid technology parameters. It is concluded that the application of spent sulfuric acid from benzol acidic refining does not have a negative influence on the crystallization process of dihydrate calcium sulfate and therefore can be applied in wet‐process phosphoric acid technology. Copyright © 2005 Society of Chemical Industry