Ethyleneglycol is commonly known as ethylene glycol, and its English name is ethylene glycol, abbreviated as EG; The molecular formula is C2H6O2 and the structural formula is HO-CH2-CH2-OH. It is the main raw material for producing polyester, polyester resin, synthetic fiber, plasticizer, surfactant and other organic products. Ethylene glycol is the simplest dihydric alcohol, which has the commonness of alcohol. It can be esterified with inorganic or organic acids and polymerized with polybasic acids to produce polyester. With the increasing market demand of polyester fiber and polyester plastics, the quality index requirements of ethylene glycol products are becoming more and more strict. At present, national standards must meet the requirements of excellent products, such as aldehyde mass fraction ≤0.0008%, ultraviolet transmittance, 220nm≥75%, 275nm≥92% and 350nm≥99%, so as to meet the needs of downstream products.

Second, the market status of China coal-to-ethylene glycol industry

China's energy structure is more coal and less oil, so the method of producing ethylene glycol from coal is gradually widely used. Preparation of ethylene glycol from coal is to prepare synthesis gas from coal, then to prepare dimethyl oxalate by catalytic reaction, and then to prepare ethylene glycol by low-pressure hydrogenation of DMO under the action of catalyst. This production method involves crude oil, ethane, coal and other raw materials.

In recent five years, China's ethylene glycol production capacity has increased year by year. According to statistics, by 202 1, China's ethylene glycol production capacity was 2 1.45 million tons, up 32.8% year-on-year, and the output was1.8 million tons, up 2 1.6% year-on-year. China has imported ethylene glycol products for many years, and the annual import volume has remained between 7.5-10.6 million tons. In 20021year, China's ethylene glycol imports reached 8,426,400 tons, down 20. 1% year-on-year. With the development of coal-based ethylene glycol technology, the production capacity will be greatly improved, and the dependence on ethylene glycol imports will be reduced in the future, thus improving the supply level.

As a new process of producing ethylene glycol from coal, the key link of purification directly determines the quality of the product. Because different companies in the market have different refining schemes for coal-based ethylene glycol, the impurity composition of the produced ethylene glycol is also different, and the quality is uneven, which directly affects the development of coal-based ethylene glycol industry.

The research shows that impurities such as esters and aldehydes mainly affect the quality of coal-based ethylene glycol, and trace esters such as diethyl oxalate, dimethyl oxalate, dimethyl carbonate, ethylene carbonate, methyl glycolate, 1, 4- butyrolactone, etc. Under the catalysis of catalyst, a part of esters are converted into polar substances and absorbed by related catalysts, and the other part is converted into substances that have no influence on the ultraviolet of ethylene glycol. Aldehydes, such as acetaldehyde and acrolein, react with ethylene glycol under the action of catalyst to produce high-boiling acetals. Some products are adsorbed by the catalyst, and the rest enter the ethylene glycol products, which will not adversely affect the indicators of ethylene glycol products, thus achieving the purposes of de-esterification, de-aldehyde, reducing aldehyde content and improving UV value. During the operation of the plant, no pollutants such as waste acid and waste alkali are produced.

Three. Brief introduction of ethylene glycol resin made from coal by Xiaolan technology

Roadmap of coal-to-ethylene glycol refining process

In view of the purification and refining of coal-based ethylene glycol industry, Xiaolan Technology has given full play to its strong strength in the field of adsorption and separation and its technical accumulation advantages for many years, organized R&D personnel to tackle key technical problems and developed two kinds of special resins for ethylene glycol refining:

seplite？ LXC-20 is a special resin for ethylene glycol in addition to formaldehyde, which has a suitable pore structure by introducing sulfonic acid active groups into styrene-divinylbenzene skeleton. The resin has the characteristics of high catalytic activity, large exchange capacity and long service life, and its main technical performance indexes have reached the international advanced level.

seplite？ LXC-30 resin is a special resin for ethylene glycol to improve ultraviolet transmittance, and it is a styrene-divinylbenzene polymer. Mainly used in ethylene glycol industry to improve the ultraviolet transmittance of products. The resin has the characteristics of high catalytic activity and long service life, and its main technical performance indexes have reached the international advanced level.

The combination of the two resins can make coal-based ethylene glycol reach the top grade.

Fourth, case display

After an enterprise in Inner Mongolia used Xiaolan ethylene glycol to refine resin, the data are as follows: