Reducing potent greenhouse gas emissions in the Russian aluminium industry

Reducing potent greenhouse gas emissions in the Russian aluminium industry

Soon the assessment focussed on the aluminium smelters within the portfolio. Aluminium production process is based on the electrolytic reduction of aluminium oxide (Al2O3) dissolved in an electrolyte where cryolite is the main component. The process takes place at 950-970 °C. The electrolytic cell is a pot lined with carbon blocks which serve as cathode. Liquid aluminium settles on the bottom of the pot since it is denser than the electrolyte. Periodically, this aluminium is siphoned off by vacuum into crucibles. Steel bars carry the electric current through the insulating bricks into the carbon cathode floor of the pot. Carbon anode blocks are suspended on steel rods, and dip into the electrolyte. This carbon is consumed during the electrolysis process. In the case of PB technology – prebake carbon anodes, burn gradually in the oxygen released by decomposing aluminium oxide, forming carbon monoxide (CO) and carbon dioxide (CO₂).

During pot operation, regularly appears a phenomenon called “anode effect” which leads to PFC emissions. Anode effect (AE) (“flare”) is the result of anode polarization during electrolysis process. AE appears when concentration of alumina (A_l2O₃) in the bath falls below critical level (1.5 to 2%) (bath “starvation”) and is characterized by the sharp increase in pot voltage because of reduced wetting of anode by the bath and increased electrical resistance on the anode-bath interface.

The project aims to reduce frequency of anode effects leading to PFCs emissions, which has a global warming potential of 6,500 (CF₄) and 9,200 (C₂F₆) times that of CO2. This emission reduction can be achieved by technical means or by operational activities. The technical measures within the scope of the projects is through operational improvements. The main operational improvements will be made in the following AEF sensitive areas: – alumina properties (e.g. moisture content); – thermal balance; – automatic process control system algorithms; – electrolysis process technology, electrolysis process practices and procedures, personnel training, analysis of pot operating parameters.

For example, for the Krasnoyarsk aluminium smelter, a 512 ha facility build in 1964, the emission reductions would amount to around 200,000 tCO₂e/year.

The smelters assessed included those in Krasnoyarsk, Bratsk, Novokuznetsk, Sayanogorsk, Khakas, Taishet, Bogoslovsk, Volkhov, Volgograd, Irkutsk, Kandalaksha, Nadvoitsky, Uralskiy, Zaporozhye.

Carbon offsetting under UN-governed mechanisms

Joint Implementation was the trading mechanism under the Kyoto Protocol for the industrialised Annex 1 countries. In practice most of the transactions were between companies and countries from Western Europe and Japan, who contracted projects in Russia, Ukraine and Central and Eastern Europe. The countries inherited a relatively inefficient power sector and heavy industry from the Soviet era. Investing in these sectors would result in more emission reductions per euro or yen invested, than if countries would only invest within their own jurisdiction.

This system of emissions trading has been instrumental in creating awareness of cost-effective emission reduction measures in the CIS region and Central and Eastern Europe. It also helped create capacity for mitigation project identification, development and impact monitoring. The downside of the mechanism however has been that, particularly in towards the end of the 2008-2012 Kyoto period, certain companies (not those examined within this project) became increasingly creative in inflating the emission reduction achievements of their investments. This undermined the credibility of the UN-governed emission trading mechanisms and its verification processes.

Client: Undisclosed

Jelmer Hoogzaad was an employee and shareholder of Climate Focus at the time of this project.