2020 is a big year for domestic ethylene glycol production. On August 24, Xinjiang Tianye Group’s annual output of 600,000 tons of ethylene glycol project successfully produced polyester-grade ethylene glycol products to meet the polyester industry’s requirements for ethylene glycol. The highest requirement of alcohol index marks that the entire process of the project has been completed and entered the production and operation stage.
It is understood that the project mainly relies on Tianye Group’s rich production experience and scientific research results in the field of coal chemical industry, and uses internationally advanced dimethyl oxalate synthesis and hydrogenation technology to produce polyester-grade ethylene glycol. It fully reflects the project’s competitive advantages of large-scale equipment, technology intensification, and production scale. The project’s core reactor production capacity, single production line scale, and product quality are in leading positions at home and abroad. It is the largest coal-to-ethylene 2 production facility currently built in China. alcohol project.
Two process routes for ethylene glycol
The industrial production process routes for ethylene glycol are divided into two categories according to different raw materials:
The first is the ethylene route, which uses crude oil, ethane or methanol as raw materials; it is the most mature process route among the existing processes and has an absolute market advantage.
The second is the syngas route, which uses coal, natural gas and coke oven gas as raw materials and is suitable for the resource characteristics of my country’s relatively abundant coal resources.
The editor will explain to you the syngas oxalate ester route used by Xinjiang Tianye to produce ethylene glycol.
The production of ethylene glycol through the synthesis gas oxalate ester route includes three steps.
At present, the domestic industrialized oxalate ester route technology holders mainly include Japan High Chemicals Co., Ltd.-Donghua Technology Company-Zhejiang Liansheng Chemical Company Consortium, China Wuhuan Engineering Co., Ltd.-Huashuo Technology Co., Ltd. Co., Ltd. – Hebi BMW Technology Group Consortium, Shanghai Pujing Chemical Technology Co., Ltd. – East China University of Science and Technology – Anhui Huaihua Group Consortium, Ningbo Zhongke Far East Catalytic Engineering Technology Co., Ltd. – China Chengda Engineering Company – Chinese Academy of Sciences Ningbo Materials Technology With the Engineering Research Institute-Shandong Hualu Hengsheng Chemical Co., Ltd. consortium, the Fujian Institute of Material Structure of the Chinese Academy of Sciences-Danhua Chemical Technology Company-Shanghai Jinmei Chemical New Technology Co., Ltd.-Henan Energy and Chemical Industry Group consortium, Sinopec, etc. Among these six technologies, Tongliao Gold and Coal’s technology is highly confidential to the outside world and has not been transferred to companies outside the group; Sinopec’s technology is only used within its own unit and is not transferred to the outside world.
The key to this technical route is the performance of the carbonylation catalyst and hydrogenation catalyst, which is closely related to system energy consumption and product quality. The ratio control of O2, methyl nitrite and NO in the oxidative esterification unit, as well as monitoring and prevention means are the guarantee of safe operation. Distillation unit design and by-product separation have an important impact on product quality and device economic benefits.
Under the premise that the oxalate ester route coal-to-ethylene glycol production technology has been basically mature, the service life of the carbonylation and hydrogenation catalysts has become the focus of production cost control.
The first-generation syngas-to-ethylene glycol SEG® carbonylation catalyst developed and produced by Gochem has a service life of more than 6 years in the Xinjiang Tianye ethylene glycol unit. In December 2013, about 11 tons of first-generation carbonylation catalyst produced by GaoChem (Jiangsu) Chemical New Materials Co., Ltd. was loaded into a carbonylation reactor of the 50,000 tons/year ethylene glycol plant in the first phase of Xinjiang Tianye (a total of two carbonylation reactor) until the catalyst of this furnace completes its mission in May 2020. In more than 6 years, a total of approximately 310,000 tons of polyester-grade ethylene glycol was produced, of which the reactor equipped with a high-chemical first-generation catalyst produced approximately 155,000 tons of ethylene glycol, equivalent to 14,000 tons of ethylene glycol per ton of carbonylation catalyst. .
Xinjiang Tianye Group began to carry out key technological research on ethylene glycol catalysts in 2013, established an ethylene glycol catalyst research and development team, mastered the core catalyst technology, and filed a total of 5 invention patent applications, which will be promoted in the future. Catalyst industrialization.
The oxalate ester route coal-to-ethylene glycol technology is almost mature, but there is still great potential to be tapped. For example, the poor stability of the hydrogenation catalyst, low ethylene glycol selectivity and high product impurities limit the long-term operation of the coal-to-ethylene glycol unit and the application of its products in the downstream polyester industry. The conversion rate of the hydrogenation catalyst , selectivity, stability and service life have become the focus of various technical parties. In terms of technical engineering support, future research and development will focus on system optimization, energy utilization, and reduction of steam and electricity consumption. It is expected that with the improvement of the technical level of coal production routes and the increase in the output of ethylene glycol products, the acceptance of downstream polyester will further increase.
Polyester production capacity continues to expand, and the ethylene glycol self-sufficiency rate is less than 50%
From 2008 to 2019, my country’s total ethylene glycol demand increased from 6.71 million tons increased to 17.852 million tons, an increase of 166.05%. As the main consumption area of ethylene glycol, polyester has the most impressive demand growth: in 2008, the demand for ethylene glycol corresponding to polyester was 6.37 million tons, and it increased to 16.77 million tons in 2019, with a growth rate of 163.27% in 10 years.
The proportion of ethylene glycol in other consumption areas is only less than 5%. The demand for antifreeze is relatively scattered and seasonal. The actual consumption in 2019 is about 260,000 tons. It is estimated that in 2020 The demand is approximately 250,000 tons. The actual consumption of ethylene glycol for unsaturated resins in 2019 is approximately 400,000 tons. The production capacity is expected to reach 5 million tons in 2020, and the demand for ethylene glycol is estimated to be 400,000 to 450,000 tons. Polyurethane’s demand for ethylene glycol in 2020 is estimated to be 250,000 to 300,000 tons.
In 2020, my country’s polyester industry production capacity is expected to reach 62.8 million tons, with output around 52.9 million tons, corresponding to ethylene glycol demand of 17.7215 million tons.
In 2019, my country’s ethylene glycol self-sufficiency rate was only 45%.In 2019, 250,000 tons of new production capacity were added, with the total production capacity reaching 11.031 million tons, a year-on-year increase of 2.3%; the output reached 8.149 million tons, a year-on-year increase of 18.3%; the capacity utilization rate was 73.9%, a year-on-year increase of 10 percentage points. Imports were 9.947 million tons, apparent consumption was 18.085 million tons, and the self-sufficiency rate was only 45%, an increase of 3.5 percentage points year-on-year.
In the future, the demand for ethylene glycol is expected to maintain a relatively stable growth trend. However, as the terminal clothing and home textile field enters a bottleneck period, the growth rate of ethylene glycol demand will gradually slow down. 2020 is a big year for domestic ethylene glycol production. In the first half of the year, Yankuang Rongxin, Zhejiang Petrochemical, and Hengli Petrochemical successively put into production nearly 3 million tons/year. The obvious expansion of the supply side has put pressure on the market; while the demand side has been suppressed by the new coronavirus epidemic. , exacerbating the contradiction between supply and demand, leading to a sharp decline in market prices.
Two major problems faced by coal-to-ethylene glycol
At present, coal-to-ethylene glycol has become a hot spot in the development of my country’s ethylene glycol industry, but There are still some shortcomings and problems:
First, economic issues. Under the current low oil prices, the original competitive advantages of coal-based ethylene glycol have been severely weakened.
The second is technical issues. The coal-to-ethylene glycol technology is not yet fully mature, and some units are running unstable, making it difficult to ensure long-term, high-load stable operation. There is a certain gap in product quality compared to the ethylene process, and it cannot be fully used in polyester production, and is mostly used in blends. In the current market environment, domestic ethylene glycol production enterprises are in a difficult situation and must further rely on scientific and technological progress to reduce costs and increase efficiency.
Compared with ethylene glycol, coal-based ethylene glycol still has the following three problems:
01 |Poor product stability, different batches of products from the same factory It may happen that some batches of products meet the standards and some batches do not;
02 |When used in the production of polyester bottle flakes, the products produced from coal-based ethylene glycol have poor light transmittance and are not accepted by the downstream. The degree is low;
03 |The production of ethylene glycol affects the dyeing of some polyester filament products and is not suitable for the production of fine denier filaments.
Therefore, so far, no polyester company has completely used coal to make ethylene glycol as raw material. In addition, very few exported polyester fiber products use coal-based ethylene glycol as raw material. The main reason is that major export destinations such as the EU have higher raw material index requirements; in addition, because the consumption of polyester bottle flakes is concentrated in drinking bottles, etc. In the field of food, food safety requirements are higher, and coal-to-ethylene glycol is basically not accepted now.
At present, although the new production capacity of coal-to-ethylene glycol is expanding rapidly, because the technology in this field is in the growth stage, there will be a mismatch in the market in the short term with rapid growth in production capacity but slow growth in output. . The coal-to-ethylene glycol process remained stable and profitable in 2019, with an average annual profit of 753 yuan/ton. The spread of the COVID-19 epidemic around the world has caused an uproar to the world economy. The financial and commodity markets have been greatly shaken. In particular, the plunge in oil prices has had a greater impact on the petrochemical industry chain. Under the background of low oil prices, the profit margin of coal-based ethylene glycol will most likely be greatly reduced, and its survival pressure will face unprecedented challenges. </p
