By Zhu Jun, Shandong Hualu Hengsheng Chemical Co., Ltd.
Dimethyl carbonate (DMC) is an environmentally friendly chemical raw material with excellent properties and a wide range of applications. Lithium ion battery electrolyte, coatings, polycarbonate, adhesives, and pharmaceuticals, as high-end application fields of DMC, have great development potential, which will be the driving force and direction of the DMC development in the future.
Demand grows steadily
Demand for DMC has steadily increased in recent years. Among the derivatives, lithium ion battery electrolyte and coatings are the major consumer markets. The lithium ion battery electrolyte is the biggest consumer (taking up more than 30% of the total consumption) and is considered to have the greatest potential.
The output of DMC was about 420 000 tons in 2018 and reached about 468 000 tons in 2019, of which, 360 000 tons were premium products (more than 99.9%), mostly based on synthetic production process. Other grades were by-products, as well purified first-class products and qualified products, and they are mainly used in the low-end coating, low-end thinners, glues, and blending industries.
In 2018, the consumption structure of domestic DMC was as below: electrolyte accounted for 30.56%; polycarbonate accounted for 22.22%; high-end coatings accounted for 13.89%; developing solutions, pharmaceuticals and pesticides accounted for 8.33% each; and polyurethane and adhesives took up 5.56%.
DMC is a green chemical intermediate to replace traditional toxic chemical products. Its growth is greatly subject to the development of downstream industries and is affected by its way to be one of the energy-saving and environmentally-friendly industries. Lithium-ion battery electrolyte, coatings, polycarbonate, adhesives, and pharmaceuticals sectors are working on developing high-end and highly environment-friendly grades. Meanwhile, the development and promotion of emerging downstream sectors will strongly drive up the DMC industry.
DMC industry in reshuffle amid upgrading technologies
In 2018, the total domestic DMC capacity was 770 000 t/a, 635 000 t/a of which were based on synthesis process, and the rest was by-products purified from synthesis gas to ethylene glycol process. Table 1 shows the main domestic DMC producers in 2018.
Table 1 China's synthesis-based DMC producers in 2018
Producer | Capacity (kt/a) | Production process |
Shandong Shida Shenghua Chemical Group | 75 | Transesterification |
Jining Shida Shenghua | 50 | Transesterification |
Shandong Haike Group | 60 | Transesterification |
Shandong Wells | 55 | Transesterification |
Taifeng Feiyang Chemical | 30 | Transesterification |
Shandong Depu Chemical Industry Science and Technology Co., Ltd. | 40 | Transesterification |
Ningbo Zhetiedafeng Chemical Co., Ltd. | 40 | Transesterification |
Taizhou Linggu Co., Ltd. | 60 | Transesterification |
CNSG Anhui Hong Sifang Co., Ltd. | 50 | Methanol oxidative carbonylation |
Jiangsu Aoke Chemical Co., Ltd. | 30 | EO transesterification |
Anhui Tongling Chemical Co., Ltd. | 90 | Transesterification |
Yulin Yunhua Co., Ltd. | 55 | Transesterification |
Some domestic DMC units were brought on stream in 2019. Wansheng New Materials put its DMC project into trial run in early 2020. Table 2 shows the domestic projects under construction or to be constructed.
Table 2 Domestic DMC projects under construction or to be constructed
Company | Capacity (kt/a) | Production process | Location | Remark |
Shandong Shida Shenghua Chemical Group | 50×2 | Vinyl carbonate transesterification | Quazhou | To be started up in 2021 |
Yangquan Coal Mining Qiandao Hengyuan Chemicals Co., Ltd. | 40 | Two-step alcoholysis of urea | Qingdao | Construction completed, but not on stream yet |
Ko Yo Chemical (Group) Co | 50 | Two-step alcoholysis of urea | Dazhou | Designed capacity of 300 kt/a, with 50 kt/a phase I project under construction |
Dongfang HOPE Group Wansheng New Materials Co., Ltd. | 60 | Methanol oxidative carbonylation | Chongqing | In trial run |
CNSG Anhui Hong Sifang Co., Ltd. | 50 | Methanol oxidative carbonylation | Zhoukou | Phase II under construction |
Zhongke Hui’an | 50 | Two-step alcoholysis of urea | Changzhi | In trial run |
Hainan Huasheng New Materials Co., Ltd. | 100 | Transesterification | Dongfang | Two 260 kt/a PC units are expected to be constructed and be put into production in 2020 |
Zhejiang Petrochemical Co., Ltd. | 100 | Transesterification | Ningbo | Under construction |
The early production processes of China's DMC products were phosgene, and the scale of the device was small. Later, due to toxicity, corrosion and environmental problems, they were gradually eliminated by the transesterification process. At present, the traditional transesterification process is still the dominant process, and the production capacity accounts for more than 90%.
At present, the traditional PO transesterification process is dominant in the domestic DMC industry, while new EO transesterification, methanol gas phase oxidative carbonylation, methanol liquid phase oxidative carbonylation, and two-step urea alcoholysis process are also used. The market competition is likely to be more furious and a reshuffle will be coming soon, as mature, reliable and comprehensively competitive processes will be leading in the market. Table 3 indicates the comprehensive comparison of some processes.
Table 3 Comprehensive comparison of different processes
Synthetic methods | Advantage | Disadvantage | Domestic application | |
Phosgenation | High yield | The process is complicated and the operation cycle is long; the raw materials are very toxic | No any plant based on the process | |
Methanol oxidative carbonylation | Gas phase | Easy access to raw materials; simple production process | Catalysts are expensive and side reaction generates small amounts of nitric acid | CNSG Anhui Hong Sifang Co., Ltd.’s 50 kt/a unit has been put into production |
Liquid phase | Easy access to raw materials; low costs; high production security | Catalyst features short life and strong corrosiveness | Wansheng New Materials Co., Ltd.’s 60 kt/a is in trial run | |
Transesterification | EO | Mature technology; large market capacity of the by-product ethylene glycol | Raw ethylene oxide is not easy to be transported and stored | Jiangsu Aoke Chemical Co., Ltd.’s 20 kt/a unit |
PO | Mature technology; raw material propylene oxide can be purchased | By-product 1,2-propanediol has limited market capacity and limited capacity per unit | Prevailing process in China | |
Urea alcoholysis | One-step | Raw materials are cheap and easily available, with no corrosion, no pollution | A large or excessive amount of methanol needed; high separation energy consumption and low selectivity | In R&Q phase |
Two-step | Raw materials are cheap and easily available, with no corrosion and high yield | Technical reliability yet to be verified | Shanxi Zhongke Hui'an’s 50 kt/a plant is in trial run; Yangmei Qingdao Hengyuan Chemical’s 40 kt/a plant has not been put into operation yet; Sichuan Ko Yo’s 30 kt/a is under construction; Hainan Huasheng New Materials Co.’s 10 kt/a unit (fed by the PC unit) | |
According to the current market conditions, the gap of cost of different processes is not big. Among the industrialized processes, the transesterification process is slightly higher in the full cost, and the methanol gas phase oxidative carbonylation process is optimal in the cost. It has not been long since the first methanol liquid phase oxidative carbonylation and urea alcoholysis units were put into production, so the two processes will have room to improve. The competitiveness of different processes is directly related to the reality of whether a producer is well equipped with raw materials and derivatives units, in addition to the characteristics of the process itself.
Although the product has excellent properties and is environment-friendly, the overall market capacity is slightly limited. Producers that do not integrate raw materials and derivatives facilities may be driven out of the market in the future.
