September 2011
Bruce Philpott
Energy Champion
Simcoa Operations Pty Ltd


Background on Simcoa

Silicon production process

Simcoa’s energy profile

EEO Opportunities – 2 examples

Evaluation of the EEO process

• Simcoa is a fully integrated silicon smelting operation located in the
Kemerton Industrial Park
• Australia’s only silicon producer
• The site consists of a sawmill, two charcoal retorts, two 27MVA submerged arc furnaces, a filter house , a product handling plant and baghouse as well as site services, laboratory, administration and maintenance areas.

• Silicon is used in both chemical and metallurgical processes, ultimately producing a range of high-tech products
• The majority of the world’s silicon is produced in China, Europe and South
America.

• Silicon is produced by the reduction of quartz at 3000 - 4000°C using a carbon reductant
• SiO2 + C → Si + CO2
• Particularly carbon and energy intensive
• International benchmark in process efficiency

• PV Solar Cells
• Silicone rubber
• Synthetic oil
• Optical fibre
• High strength aluminum alloys
• Silicon chips
• Synthetic quartz

Energy
Inputs
Electricity
Natural Gas
Diesel
LPG
GJ
(Approx)
1,400,000
70,000
12,000
500
• Total energy use at the Kemerton site is approximately 1.5 PJ per year.
•
The submerged arc furnaces use about 90% of the site’s electrical power with a load of 41 MW
• The process is highly endothermic requiring approx 11 MWh/tonne of silicon
• The furnaces are currently operating at worlds best practice levels in terms of electrical efficiencies, so opportunities for improvement are limited
.

• Considerable scope for projects that can capture and use waste heat from the smelting process or minimize furnace downtime.
• Projects that recover energy (waste heat) are normally only feasible if considered at the design stage.

• Assessment identified 10 opportunities with a total energy saving of 41,000 GJ
• 4 of these opportunities have been implemented, 4 are to be implemented,
1 is under investigation and 1 not to be implemented.

Replacement of steel contact pads with copper pads
Energy saving calculated as ~10,000 GJ.

Optimize use of ladle pre-heater Natural Gas
Historically spare ladles heated under gas fueled pre-heaters so that they could be immediately called into service – with better planning they can be maintained at a lower temperature, which is increased before use
Energy saving calculated as ~8,400 GJ.

• Being one of the first participants it was difficult to estimate resources needed – in hindsight probably underresourced
• Identified savings that did not require significant expenditure (for example ladle preheating)
• Use of energy bandwidths, while sometimes necessary, can be confusing

• Lack of continuity of staff makes reporting difficult
• Second cycle will provide an opportunity to apply the knowledge and skills learnt from networking, workshops etc
• Short payback period does not make opportunities a sure thing i.e. other variables such as technical risk, cash flow, other strategic priorities etc will influence decision making

 For new plant – EEO evaluation at design phase would be helpful – for example new silicon furnace is designed for future energy recovery