碱减量废水中回收对苯二甲酸资源再用

碱减量加工过程中产生了大量的废水,其中包含一定深度的对苯二甲酸盐（TPA-Na2）,经酸析回收处理可得到一定数量的对苯二甲酸和乙二醇,纯度都低于正规产品。研究了从碱减量废水中回收对苯二甲酸,并资源再用于聚酯涂腊的制备,不但有效解决了碱减量废水综合治理问题,并极大增加了回收产品的再用价值。     

碱减量废水中回收对苯二甲酸资源再用

研究了从碱减量废水中回收对苯二甲酸,并再用于聚酯涂膜的制备,有效解决了碱减量废水综合治理问题,并提高了回收产品的再用价值.     

碱减量废水中回收对苯二甲酸的过程分析

根据国内己运行的碱减量废水中回收对苯二甲酸装置运行实践,就如何提高回收品质、降低回收成本的相关因素,进行过程分析和探讨,并提出对策建议.     

碱减量废水中回收对苯二甲酸资源再用

从碱减量废水中回收对苯二甲酸,分析酸析工艺条件对回收产品的性能影响因素趋势;将得到的回收产品资源再用,作为原料制备聚酯涂膜,因回收产物纯度低于正规产品,试验加入甘油进行共聚合改性。在酸析回收工艺试验中确定了对回收资源性能的影响显著性大小依次为:酸析反应温度、废水碱度、搅拌速度、加酸速度、硫酸浓度。在最佳的工艺条件下,对苯二甲酸回收率为81%。在资源再用共聚合工艺试验中确定了加入官能度大于2的单体甘油,是产生支化和导致体型产物的根源,而多元醇的超量使用使得高分子聚合物在聚合过程中随着分子量增大不致产生凝胶化。实验表明,当原料酸醇比为1∶2.5,三元醇与二元醇摩尔比为1∶3时,资源再用产物的性能较为理想。     

涤纶织物碱减量处理废液中对苯二甲酸的回收

涤纶碱减量废液由于其碱度大、有机物含量高,治理起来相当困难。本课题研究了用酸析法从废液中 回收对苯二甲酸的可行性及影响因素。采用适当的工艺可以从碱减量废液中回收纯度为99.8％的对 苯二甲酸,回收率为83％左右,同时CODer的去除率为82％,实现了资源化治污。     

上海大学开发出PET纤维碱减量工艺废水中对苯二甲酸的回收方法

<正>上海大学开发出一种PET纤维碱减量工艺废水中对苯二甲酸的回收方法。回收处理的主要工艺过程是:先将废水在适宜p H条件下用混凝剂净化去杂,然后分步调节废水p H,在不同的p H阶段使用适宜的助凝剂增强析出物的沉降性能、增大析出物的粒径、提高析出物的过滤率,过滤后获得高纯度的对苯二甲酸。同时,出水的COD去除率达78%以上,废水的可生化性大幅提高,便于后续水处理的达标排放与综合利用。     

碱减量废水膜法集成处理技术

研究了膜法集成技术在碱减量废水处理中的应用.通过膜技术可以将碱减量废水中的对苯二甲酸钠分离成浓缩液,经过酸析处理,不仅可以从浓缩液中回收得到纯度90%以上的对苯二甲酸,而且加酸量仅为直接酸析法的1/3.同时,碱减量废水经膜处理和酸析后,COD可以降低70%以上.膜法集成技术还能够将含有乙二醇的碱液从碱减量废水中分离出来,乙二醇可以通过反渗透等膜技术分离回收,而碱液可以通过添加液碱的方法重新用于碱减量过程.     

回收利用粗对苯二甲酸

介绍了回收利用聚酯生产中所产生的废对苯甲酸的工艺及效果，每年可回收３００ｔ，效益１００万元，节约了能源，实现了变废为宝。     

对苯二甲酸回收再利用的研究进展

在对苯二甲酸(TPA)的生产和再加工过程中,会产生大量废弃物,其中TPA是其主要污染源。从TPA分离提纯、回收再利用的角度出发,介绍了酸析法、盐析法、重结晶法和膜处理法等方法,同时阐述了各自的优缺点及研究现状。最后提出多种方法合理的结合才能达到最佳的效果,指出了TPA回收再利用的发展方向。     

从废渣中回收对苯二甲酸

对苯二甲酸(TPA)生产所排废水中含70%～80%的TPA。通过先加NaOH,再加H_2SO_4等反应过程,可以得到纯度98%的TPA,适宜作为生产对苯二甲酸二甲酯和二辛酯等的原料。     

Recovery of Terephthalic Acid from Alkali Reduction Wastewater by Cooling Crystallization

A process for the recovery and purification of terephthalic acid (TA) from alkali reduction wastewater is reported. TA was first precipitated from alkali reduction wastewater by acidification with sulfuric acid, and then the produced crude TA was dissolved in dimethylacetamide (DMA) so that crude TA could be purified from the solution by cooling crystallization. The results indicated that acidification could reduce the chemical oxygen demand of the wastewater by 83 %, and the purity of TA by crystallization could reach 99.91 %. A correlation was proposed in describing the solubility of crude TA in DMA from 303.4 to 358.65 K, which gives a mean relative discrepancy of less than 1.14 %. The cooling rate of the mother liquor had a large influence on the crystal size distribution. At an average cooling rate of 1.18 K min^–1, the particle size distribution of TA was narrow and the average size was about 100 μm. In a bench‐scale study, it was demonstrated that the crystallized product can be recycled as the raw material for polyethylene terephthalate production.     

集成膜技术深度回用处理精对苯二甲酸废水研究

近两年来,膜法回用石化废水备受重视,利用集成膜技术对炼油和乙烯化工废水进行深度回用处理,目前已有相对成熟的经验,但集成膜技术用于精细化工产品精对苯二甲酸废水回用处理的研究尚少。在试验基本工况为超滤系统采用全量过滤方式,运行周期30min,内压式超滤运行通量不大于75L/(m2.h),超滤系统前加入絮凝剂PAC(投加量为5mg/L),低污染反渗透膜运行通量不大于19L/(m2.h),试验中系统回收率为70%,反渗透进水的COD含量小于40mg/L的条件下,精对苯二甲酸达标废水深度回用处理稳定运行,产水水质稳定可靠。     

碱减量废水残渣甲酯化反应动力学研究

为实现碱减量废水残渣有效利用,对碱减量废水残渣甲酯化反应条件与反应动力学规律进行了系统考察。论文首先考虑洗涤干燥等预处理方法对碱减量废水残渣组成的影响,然后通过改变醇酸比、初始水分含量及反应温度条件,进行了碱减量废水残渣甲酯化反应动力学实验研究。结果表明,预处理可有效去除残渣中的无机盐杂质提高对苯二甲酸纯度,但预处理会明显降低后续残渣甲酯化产物对苯二甲酸二甲酯(DMT)的收率以及对苯二甲酸(TA)甲酯化反应的转化。TA甲酯化两步反应均对温度敏感,采用典型的可逆平衡反应模型对实验数据进行拟合,得到动力学模型参数,并在此基础上对动力学模型进行检验,结果表明所建立的动力学模型是可靠的,能很好的预测各组分的浓度。研究所得可为碱减量废水残渣甲酯化工艺放大与设计提供依据。     

精对苯二甲酸生产废水处理技术

立足于实践工作经验,对精对苯二甲酸(PTA)生产进行简要分析,说明生产废水处理技术的重要作用。对精对苯二甲酸生产废水主要特点加以总结,从物化处理技术和生化处理技术两个方面,说明生产废水处理技术的应用及污水减量化发展前景。     

油田污水的油品回收及处理技术研究

对某油田污水采用“N2气浮厌氧—O2好氧强化A/O法”工艺流程实现油品回收,污水回注及排放的有效性和适用性进行了实验研究.试验结果表明,在原水水质中石油类在55～160 mg/L,COD含量在390～630mg/L,BOD含量在70～110 mg/L,SS在40～200 mg/L,该工艺对石油类、悬浮物的去除率可达90...     

Poly(ethylene terephthalate) Recycling and Recovery of Pure Terephthalic Acid. Kinetics of a Phase Transfer Catalyzed Alkaline Hydrolysis

Poly(ethylene terephthalate) (PET) taken from post‐consumer soft‐drink bottles was subjected to alkaline hydrolysis with aqueous sodium hydroxide after cutting it into small pieces (flakes). A phase transfer catalyst (trioctylmethylammonium bromide) was used in order the reaction to take place in atmospheric pressure and mild experimental conditions. Several different reaction kinetics parameters were studied, including temperature (70–95°C), NaOH concentration (5–15 wt.‐%), PET average particle size, catalyst to PET ratio and PET concentration. The disodium terephthalate received was treated with sulfuric acid and terephthalic acid (TPA) of high purity was separated. The ¹H NMR spectrum of the TPA revealed an about 2% admixture of isophthalic acid together with the pure 98% terephthalic acid. The purity of the TPA obtained was tested by determining its acidity and by polymerizing it with ethylene glycol using tetrabutyl titanate as catalyst. A simple theoretical model was developed to describe the hydrolysis rate. The apparent rate constant was inversely proportional to particle size and proportional to NaOH concentration and to the square root of the catalyst amount. The activation energy calculated was 83 kJ/mol. The method is very useful in recycling of PET bottles and other containers because nowadays, terephthalic acid is replacing dimethyl terephthalate (the traditional monomer) as the main monomer in the industrial production of PET.     

Preliminary Evaluation of Alternatives to Distillation for Acetic Acid Recovery from Terephthalic Acid Flowsheets

Abstract

Acetic acid is presently recovered from terephthalic acid flowsheets by distillation. This paper documents a preliminary evaluation of extraction for its recovery and recycle. Experimental data show that the solvent has a selectivity for acetic acid-water of 5 for a 50 wt. percent acid solution and 60 for 5 wt. percent acid solution. Above 10 wt. percent extractant in the solvent, addition of extractant to the solvent has the combined effect of decreasing the solvent loss to the aqueous phase and decreasing the loading of water in the solvent. The high selectivities of the solvent for acid vs. water combined with the high relative volatility of the acid vs. the solvent imply that lower energy costs with an extraction flowsheet over distillation is likely.