The Propylene Oxide Problem
Propylene oxide (PO) is in strong demand, especially for polyurethanes applications, but tight control on the technology is limiting the building of new plants. PO is one of the fastest growing uses of propylene, with production up 3.5%/year from 2010-2016. Given the forecast growth rates, more PO units need to be built to satisfy demand. But planned plants are few and far between with technology limitations strong. However, this could change in the near future as the Chinese launch new production processes. PO technology is currently in its third generation. In 2006 Sumitomo developed a method using oxidation by cumene hydroperoxide. The by-product cumyl alcohol can be recycled back to cumene. This was followed in 2008 by technology oxidising propylene with hydrogen peroxide (HPPO), with water the only by-product. This was simultaneously developed by Degussa-Uhde (now Evonik) and BASF/Dow Chemical. Sumitomo’s technology has not taken off to the extent the company hoped. There are only two plants globally – the original one in Japan and one in Saudi Arabia, launched in 2009 by PetroRabigh, a Saudi Aramco/Sumitomo joint venture. Another two are planned to open in Asia, with licences from Sumitomo. One will open in 2018 in South Korea, operated by S-Oil. The second is in Thailand, operated by PTT Global Chemical and due to start in 2019. Industry sources say this process is complex and costly, and has been overshadowed by the newer, more efficient HPPO process. HPPO is a relatively simple process with few by-products. As such, it is seen as the most modern, cost efficient process. Degussa-Uhde claim the first plant – built in 2008 by SK Chemicals in Korea. This was very shortly followed by a BASF/Dow plant in Antwerp also in 2008. More plants came from BASF/Dow – a plant in Thailand in 2011, and a Dow joint venture Sadara Chemicals opening in Saudi Arabia in 2017. Degussa-Uhde (now owned by Evonik) sold the technology under licence to Jishen Chemical industries in Jilin, China (from 2014). However, a couple of Chinese players are working on their own HPPO technologies and this could be a game changer for the PO market. If Chinese players are successful, this could lead to a new wave of PO plants and a loosening of supply. Source: ICIS Chemical Business, 7/6/2017.
TCGR Note: The original process was the propylene chlorohydrin route used by Dow Chemical. This was superseded by oxidizing propylene using organic peroxides e.g. tert butyl peroxide (TBP) but copoducts like MTBE or styrene made POSM plant investment decisions difficult. RIPP/Sinopec are one of the Chinese groups working on HPPO technology. They began operating a commercial demonstration unit in late 2015 (see CAP Communications dated 10/19/2015).