26. Februar 2018 | Branche, Technologie

EGA reaches record low level of perfluorocarbon emissions

Aluminium producer Emirates Global Aluminium (EGA), UAE, released that its emissions of perfluorocarbons (PFCs) were a record low for the company in 2017, and that EGA has signed an agreement with the University of New South Wales to research further reductions.

PFCs are a group of greenhouse gases which have thousands of times more global warming potential of carbon dioxide. Reducing PFC emissions is an important environmental goal of the global aluminium industry. EGA’s emissions of PFCs were 22 kilograms per tonne of aluminium produced in 2017 compared to a global average of 380 kg/t in 2016, the most recent year for which figures are available from the International Aluminium Institute (IAI). At EGA’s newer Al Taweelah smelter (Emal), PFC emissions in 2017 were 7 kg/t of aluminium produced.

In the aluminium industry reported PFC emissions are known to be associated with momentary process imbalances known as anode effects. These occur when the alumina concentration falls in the reduction cells in which aluminium is smelted. Through technology development and operational improvements, EGA has reduced the frequency of anode effects in its operations from an average of once every three days in each reduction cell in 2009 to less than once every 12 days in each reduction cell in 2017. The average duration of each anode effect has similarly decreased, from 44 seconds in 2009 to below 21 seconds in 2017.

The new research that EGA will conduct with scientists from the University of New South Wales aims to reduce what the industry terms ‘background’ PFC emissions – those that are from variations in reduction cell conditions that are too small to be detected and remedied by the control technology available today. The research will focus on developing sophisticated technology to continuously monitor conditions inside reduction cells in great detail and semi-autonomously feed alumina in response to minute changes.

More accurate feeding of alumina in response to changing conditions is also expected to lower energy consumption, reducing emissions of CO2 created through power generation.

EGA’s work to reduce PFC emissions is led by executive vice-president Ali Al Zarouni, who is in charge of the company’s aluminium smelters in Abu Dhabi and Dubai and EGA’s technology development. He holds a PhD in Chemical Engineering from the University of New South Wales and wrote his doctoral thesis on the subject of ‘PFC emissions in the aluminium industry’. He says: “Reducing PFC emissions in the aluminium industry is a matter of fundamental environmental responsibility. Unfortunately no single factor provides the solution. Rather, we have achieved our reductions through developing our own smelting and pot control technology, continuously improving our operational processes and rigorously monitoring the quality of our raw materials. We believe our new research is the first of its kind as it aims to tackle emissions from minute changes rather than just reducing anode effects that we can all detect today. Working with the University of New South Wales enables us to combine our own technology expertise with the latest academic thinking to tackle this particularly difficult challenge.”

The new project is the third research partnership between EGA and the University of New South Wales. Previous research with the university has focused on developing more sophisticated measurements within reduction cells and the findings will be used in the new research work.

EGA is a member of the IAI and supports the Institute’s voluntary target of a 93% reduction in perfluorocarbon emissions at older smelters by 2020 (using 1990 as the baseline). EGA Jebel Ali achieved this reduction by 2015 – five years early. EGA has reduced its total greenhouse gas emissions produced per tonne of aluminium by 10% since 2011.