Danhua Technology reaches new levels in coal-based ethylene glycol production

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Danhua Technology Reaches New Levels in Coal-Based Ethylene Glycol Production Author/Source: China Chemical Industry News Date: 12-07-2018 Clicks: 9 Recently, there has been significant interest in investing in projects for producing ethylene glycol from coal. What are the actual operating conditions and economic benefits of such projects? At the beginning of December, reporters from China Chemical Industry News visited Danhua Chemical Technology Co., Ltd., which operates the world’s first plant for producing ethylene glycol from coal. 　　Wang Bin, chairman of Danhua Technology, told reporters that the 200,000-ton per year coal-to-ethylene glycol plant operated by Danhua Technology’s subsidiary, Tongliao Jinmei Chemical Industry Co., Ltd., is the world’s first production facility to use syngas to produce oxalate esters, which are then hydrogenated to yield ethylene glycol. The plant came online in 2009 and reached full capacity on November 18, 2011. Through annual technical upgrades and adjustments, the unit underwent its final upgrade in June and July of this year. After being put into operation in mid-July, its load gradually increased to over 90%, and its performance improved steadily. Since the second half of the year, the plant has been operating at high capacity with stable production. Currently, the daily output of ethylene glycol remains above 600 tons; the one-pass conversion rate of the synthetic raw material, methyl nitrite, is 80%. The plant operates at 100% capacity, and the quality rate of high-grade ethylene glycol is 100%. Both the material consumption and energy consumption per ton of product are at leading levels in the industry. The daily production volumes of ethylene glycol and oxalic acid once reached record highs of 613 tons and 280 tons, respectively. 　　According to him, the technical upgrades carried out in July this year focused on optimizing the dimethyl oxalate synthesis system, as well as cleaning the heat exchangers and pipelines in the distillation system. After the technical upgrades were completed in August and the catalyst was installed for operation, the one-pass conversion rate of methyl nitrite, the raw material in its synthesis system, increased from 75% to 80%. 　　As of the time of writing, the device has been in continuous operation for 145 days. From August to November, the total production of ethylene glycol by this facility was approximately 69,800 tons, while the production of oxalic acid was around 31,100 tons; profits amounted to about 130 million yuan. Over the past two months, its daily production of ethylene glycol has remained above 600 tons. For each ton of ethylene glycol produced, approximately 780 Nm3 of carbon monoxide and 1540 Nm3 of hydrogen are consumed. At the same time, its energy consumption has further decreased; the amount of steam required per ton of ethylene glycol produced has dropped from around 5.5 tons to about 5.2 tons, achieving a level that is ahead of industry standards. This has enabled the company to achieve a balance between production and sales, with no inventory of products. 　　Regarding the quality of coal-based ethylene glycol, an issue of great concern in the industry, Danhua Technology maintains a 100% rate of high-quality ethylene glycol production. The light transmittance values of its finished ethylene glycol products at 94/220nm, 98/250nm, 99/275nm, and 100/350nm all meet the latest **polyester-grade standards. “Several domestic polyester manufacturers that have been using Tongliao Jinmei ethylene glycol products for over a year have reported no issues at all, with no impact on the quality of the polyester. At present, all of our ethylene glycol products are sold to downstream polyester manufacturers. ”Wang Bin said. 　　Parameters such as the high selectivity, high conversion rate, low cost, and long service life of catalysts are key factors determining whether the coal-to-ethylene glycol technology is advanced and whether the resulting product is competitive. Wang Bin told reporters that the Tongliao Jinmei project uses catalysts produced by Jiangsu Jinju Alloy Materials Co., Ltd., a subsidiary of Tongliao Jinmei. At present, Jinju Company operates two automated production lines, enabling it to produce 3,000 tons of coal-to-ethylene glycol catalysts per year – the highest output in the country. The catalysts produced are supplied exclusively to Tongliao Jinmei and Henan Yongjin’s six coal-to-ethylene glycol production lines, with a total annual capacity of 1.2 million tons. 　　Among them, the selectivity of the synthetic catalyst DMO exceeds 99.5%, the one-pass conversion rate of methyl nitrite is over 80%, and its normal service life is around 2 years. During use, it addresses a series of issues such as high heat generation during the carbonylation reaction, significant peak temperatures, and intense side reactions. During operation, the hydrogenation catalyst exhibits excellent properties of high activity in low-temperature reactions; the selectivity for ethylene glycol exceeds 98%, the product quality remains stable, the DMO conversion rate is 100%, and its normal service life is around 1.5 years. 　　“The efficient and stable operation of the two key catalysts has led to a significant reduction in energy consumption and material usage in the production of ethylene glycol from coal. ”Wang Bin said that the cost of the ethylene glycol catalyst per ton at Tongliao Jinmei is currently around 150 yuan.