Rio Tinto’s Yarwun refinery features a cogeneration facility, which has reduced emissions at the site and saw the company named as a finalist of the industrial eco-efficiency award category at the 2011 Queensland Premiers Climate Smart Sustainability Awards.
In July 2007, Rio Tinto announced the US$ 2.3 billion expansion of its Yarwun refinery, a growth project referred to as “Yarwun 2”. The 160 megawatt gas-fired cogeneration facility, comprising of an electrical generator, gas turbine and heat recovery steam generator was a key element of the Yarwun 2 project.
The cogeneration facility, which was successfully commissioned in August 2010, converts natural gas energy via a large gas turbine to produce electricity and steam for the refinery.
The gas turbine is linked to a 160 megawatt electrical generator, which produces all the electricity needed to power the refining processes. Waste heat from the gas turbine exhaust is captured and used to produce steam for the refining process, with surplus electricity being exported to the Queensland electricity grid. This electricity has about one-third the emissions intensity of coal-fired electricity.
This type of cogeneration technology or ‘combined heat and power’ technology provides greater conversion efficiencies than traditional generation methods. It harnesses heat that would otherwise be wasted, and importantly, reduces greenhouse emissions.
The cogeneration facility now provides a stable and self-produced steam and electricity supply for the refinery, delivering a significant reduction in the operation’s greenhouse gas emissions.
The facility also has low oxides of nitrogen burners, together with a desulphurisation unit to reduce nitrogen dioxide and sulphur dioxide emissions.