Research Of Discolorment Mechanism And Decolorization Method Of SEG

As an important chemical raw materials and intermediates in chemical industry,Ethylene glycol has a very wide application. Coal-based Ethylene glycol is a new technology that is different from the traditional petroleum route,and has a rapid development in recent years. Because of the raw material and the synthetic route are different, the impurities contained in the Coal-based Ethylene glycol products are more complex,and resulting in a series of quality problems such as the discoloration. Currently,reports on improving the quality of coal-based ethylene glycol are less,and do not form systematic improvement measures. Therefore the research and analysis on discoloration problem and forming systematic solutions can provide a basic gist for improving the quality of coal-based glycol.In this project we focus on the following aspects :studying the influence factors that affect the quality indicators of ethylene glycol;researching the effect and suitable conditions of ultraviolet irradiation; studying the effect and suitable treatment conditions of adsorption by activated carbon.Results of the research are as follows:1 、 The preservation conditions of sample have an impact on the product quality. Lighting can improve the quality to some extend,and exposure to the air has a dual effect on the quality,not only produce aldehyde to influence the UV value,but also conducive to the spreading of some material to the air.2、The presence of impurities can influence the UV value of sample,and different kinds of impurities has a different influence on the UV value of sample, the impurities which have a large impact on the UV value of sample should be mainly removed.3、The UV of sample can be improved by using the method of lighting,and there is an obvious improvement on the UV value of ethylene glycol sample with the UV-light wavelength range of 245nm-275 nm,through the experiments we can know that the irradiation intensity、lighting time as well as the distance from lighting source to the samples can have an obvious impact on the improvement results. Method of UV irradiation treatment is more suitable for dealing with samples that unqualified at the wavelength of 275 nm to make the time of treatment is short.4、Adsorb the samples with activated carbon,make the coconut shell activated carbon as the suitable adsorbent and the phosphoric acid as suitable modification reagents,and the suitable conditions of processing as follow:The concentration of phosphoric acid is 5%,processing time is 4 hours;The adsorption time is 2hours,Liquid-solid ratio is 300:1. The experiments indicate that the method of adsorption by activated carbon has a more obvious impact on the improving of UV value at the wavelength of 220 nm.The advantages and disadvantages of the two kinds of improvement methods complement each other,and form a systematic measures for improving the UV value of coal-based ethylene glycol. In actual industry,we can take proper methods to improve the products due to the status of samples.