Monomers

Monomers are a collective name of small molecules that can have polymerization with molecules of the same group or other groups. They are simple compounds that can form polymer compounds through polymerization or polycondensation. Monomers are low-molecular raw materials used in the synthesis of polymers. They are usually unsaturated and cyclic or contain two or several functional groups.

Ethylene is a core monomer in the petroleum and chemical industry. Ethylene based products account for over 70% of petrochemicals, therefore ethylene plays an important part in the national economy. Ethylene is widely used to produce polyethylene, polyvinyl chloride and polystyrene, it is also used to synthesize various basic raw materials such as ethanol, ethylene oxide, ethylene glycol and acetaldehyde. Moreover, ethylene can be used as standard gas for analytical instruments in petrochemical enterprises and also as environment-friendly gas for fruit ripening.

The output of ethylene is one of the important indicators to evaluate a country’s petroleum and chemical industry development level. With the rapid development of the economy, China’s ethylene industry grew rapidly in recent years. As ethylene capacity expanded fast, China has become the world’s second largest ethylene producer, only next to the United States. The country’s ethylene capacity reached 23.1 million t/a in 2016, up 5% year on year and the CAGR was 5.8% in the past decade. The newly added capacity in 2016 reached 1.1 million t/a, which all came from CTO/MTO process. China’s CTO capacity has reached about 4.5 million t/a, accounting for 19% of the total ethylene capacity. There are 17 CTO units now. As CTO units are put on stream one after another, the ethylene capacity proportion of CNPC and Sinopec has been declining in recent years. The proportion was 72.8% in 2016. CNPC had 7 manufacturing companies and 12 ethylene units, while Sinopec had 14 manufacturing companies and 16 ethylene units.

As more CTO units were built, the newly added capacity of ethylene grew significantly in recent years. However, as oil prices fall, coal-to-olefins (CTO) process’ economic benefits are not so lucrative than before, as compared to naphtha-to-olefins process. The operating rate of coal chemical units is down and the overall operating rate of the olefin industry is affected.

It is requested by the Chinese Government that the scale of planned and new ethylene units should reach 1.0 million t/a and the scale of new CTO/MTO units should be above 500kt/a. The scale of domestic-funded or joint venture naphtha cracking units being constructed or planned for construction are all 800kt/a and above. The scale of ethylene production in China will therefore reach a high level during the 13thFive-Year Plan period. In terms of production process, the traditional cracking process will go in parallel with the coal chemical route. With the rebound of the international oil price, CTO’s economic benefits will also recover. As the Chinese government will further promote CTO demonstrative projects, it is therefore expected that by 2020, planned projects or projects under construction will commercialize 11.8 million t/a ethylene capacity. At the time, the capacity of ethylene in China will hopefully reach 34.90 million t/a. The capacity of CTO will be 6.90 million t/a, accounting for 19.7% of the total.