Coal-to-Olefins Industrialization Advanced Smoothly in China in 2011   

By Sang Jianxin, China National Chemical Information Center

The year of 2011 is a transition year for China's coal-to-olefins (CTO) projects, the year for plants to shift gradually from their demonstration phase into commercial operation. After nearly one year of industrial operation, Shenhua Baotou CTO project has achieved good economic benefits, verifying the feasibility and economics of its CTO technology, and thereby encouraging businesses and the Chinese government greatly. As a result, government restrictions on CTO have been loosened, and a number of new CTO projects have been proposed.

Progress of major CTO projects

In 2011, three CTO plants in China were put into operation, and Sinopec Zhongyuan Petrochemical Co Ltd (hereinafter referred to as Zhongyuan Petrochemical) also transformed a petroleum-based olefins plant into a coal-based olefins plant, bringing China's total CTO capacity to 1.805 million t/a, including a coal-to-ethylene capacity of 406 000 t/a and a coal-to-propylene capacity of 1.399 million t/a.
    Shenhua Baotou 600 000 t/a CTO project: The plant was put into commercial operation on January 1, 2011. It was planned to produce 450 000 tons of polyolefin (PE and PP) in 2011. But in fact, by November 2011, its polyolefin output had exceeded that goal, and the plant had a total sales revenue of RMB3.99 billion, achieving significant economic benefits.
    Shenhua Ningmei 500 000 t/a coal-to-propylene project: Construction of the plant was completed in August 2010. In April 2011, its gasifer achieved stable operation. At the end of April, its propylene, PP (polypropylene) and packaging units were successfully put into trial operation. In May, the plant was put into commercial production. In May 2011, it produced 48 000 tons of methanol, 17 000 tons of propylene, 2 300 tons of LPG, 5 500 tons of mixed aromatics and 13 000 tons of PP.
    Datang Duolun 500 000 t/a coal-to-propylene plant: The plant site is in Duolun, Xilin Gol League in Inner Mongolia. Its main raw material is lignite dug from No.2 opencast mine in Shengli coal field in Inner Mongolia. The project set a number of world and domestic records: the plant's single gasifier can handle 2 800 tons of dried coal a day and is the world’s largest; the plant has three such gasifiers, and this is also a world record; its Rectisol gas processing volume is the world's largest; its methanol unit is one of the world's three largest (all 5 000 t/d); its MTP (methanol-to-propylene) unit is the world's first industrial MTP unit; and its PP production capacity is 460 000 t/a, China's largest.
   The plant was put into trial production in the second quarter of 2010. In January 2011, the MTP unit's reaction system was successfully put into operation, and its methanol conversion rate met the design requirements. In the first half of 2011, two of its gasifiers were successfully put into operation. At the end of June, it produced qualified methanol. On August 29, the MTP unit smoothly produced distilled propylene. Management planned to produce the end product - qualified PP - before the end of 2011.
    Zhongyuan Petrochemical's transformation project: For its 106 000 t/a polymer-grade ethylene and 99 000 t/a polymer-grade propylene units, Zhongyuan Petrochemical transformed the units' feed route from light hydrocarbons and naphtha cracking route into the methanol-to-olefins route. In October, the transformation project was completed and the re-engineered plant produced qualified polymer-grade ethylene and propylene. The plant uses Sinopec's proprietary SMTO technology, and the manufacture of all its major equipment and catalysts have been achieved domestically.

A sharp increase in the number of proposed CTO projects

After the National Development and Reform Commission (NDRC) issued the Notification on Strengthening the Management of Coal-to-Liquids Projects in August 2008, some enterprises changed their planned/proposed coal-to-liquids plants into coal-to-olefins plants. And due to the financial crisis, domestic alcohol and ether markets suffered a downturn, so some large-scale alcohol and ether plants plan to be transformed into methanol-to-olefins (MTO) plants, making the number of planned CTO/MTO projects in China increase sharply. It was learned that the number of proposed CTO projects in China reached 36 by the end of 2011, and they have a total planned methanol capacity of about 85 million t/a and a total planned olefin capacity of about 28 million t/a, including an imported methanol-to-olefins capacity of 4.5 million t/a in coastal areas. These projects have the following two characteristics:
    (1) They are all upstream- and downstream-integrated projects and have the same route: coal -> methanol -> olefins. And the plants with PE as their end product will all be equipped with the full-density PE production equipment that can switch over to producing LLDPE and HDPE.
    (2) In order to pursue economies of scale and to be in line with the industry access policy, many projects take the strategy of applying for large capacity but building it in phases.
   If all these projects are completed on schedule, by 2015 China's coal-to-ethylene production capacity will reach 6.455 million t/a, and its coal-to-propylene capacity will reach 9.049 million t/a.

Advances in the CTO/MTO technology

The DMTO technology adopted by the Shenhua Baotou CTO project was independently developed by Dalian Institute of Chemical Physics (DICP), Chinese Academy of Sciences. Its selectivity for ethylene and propylene is greater than 78.71%, and it consumes three tons of methanol to produce one ton of olefins (ethylene + propylene). The new-generation methanol-to-olefins technology, the DMTO-II technology, jointly developed by Shaanxi Coal Chemical Group, Sinopec Luoyang Petrochemical Engineering Corporation and DICP, has a methanol conversion rate of 99.97%, and its selectivity for ethylene + propylene is increased to 85.68%; and it uses only 2.67 tons of methanol per ton of ethylene + propylene, 11% less than DMTO technology. Shaanxi Pucheng Clean Energy Chemical Co Ltd will use the DMTO-II technology to construct a 1.8 million t/a coal-to-methanol and 700 000 t/a methanol-to-olefins project.
   In 2011, China's CTO industry made remarkable progress. Shenhua Baotou CTO project was put into commercial production and achieved gratifying results in production and operation, verifying the reliability and economics of DICP's DMTO technology, and establishing success for the CTO technology. In addition, the application of Sinopec's SMTO technology was also promoted. China's CTO technology now leads the world.

Related policies came out one after another

On April 6, 2011, the NDRC issued the Notification on Regulating Orderly Development of Coal Chemical Industry, which prohibits the construction of coal-to-methanol projects that have a capacity of 500 000 t/a or less; and until the new approval catalogue comes out, any coal-to-olefins project must be approved by the NDRC.
   The Planning for Coal Deep-processing Demonstration Projects issued by the NDRC, the National Energy Administration (NEA) and the Ministry of Industry and Information Technology (MIIT) proposes to expand the scope of CTO and coal-to-gas (CTG) demonstration projects and to actively promote CTO and CTG technologies which consume less energy and water.
   The Twelfth Five-Year Plan for Ethylene Industry, formally launched in 2011, clearly states: China will accelerate the construction of large ethylene projects which are under construction, expand the capacity of