Increased energy consumption due to elevated anode resistivity HAR ALUMINIUM is a smelter in Oyland using western tehnology Smelter has production capacity of 500 000 tonyear With decent performance figures CE 945 energy consuption 136 MWht Al anode current density 08 Acm2 The energy ID: 610913
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Slide1
Group discussion 1
Increased energy consumption due to elevated anode resistivitySlide2
HAR ALUMINIUM is a smelter in Oyland using western tehnology. Smelter has production capacity of 500 000 ton/year. With decent performance figures ( CE 94,5%, energy consuption 13,6 MWh/t Al, anode current density 0,8 A/cm2) The energy price is 60 USD/MWh.
The new potroom manager is seeking for opportunities to reduce energy consuption of the smelter. Test result of the routine anode quality control reveal typical values for most properties, but elevated weekly average figures for the specific resistance of up to 63 µ
Ω
m. As a former carbon plant manager he knows that the bench mark figure is 53 µ
Ω
m
for anodes produced with comparable tehnology. The baked anodes have a hight of 650 mm and a stub depth of 100 mm.
What is the impact of the elevated anode resistivity on the energy consuption and accordingly the smelter cost?
What are potential root causes for this elevated anode resistivity?
How can the root causes for the elevated anode resistivitz be eliminated?Slide3
Anode drawingSlide4
What is financial impact on the smelter
costs
?
U
Δ
U
= 28 mV
Δ
E ΔU (1/CE) * 2,98 = 0,028 * (1/94,5) * 2.98 = 0,09 kWh/kg = 0,09 MWh/ton Al
For the 500.000 tpa smelter it is 500 000 * 0,09 = 45 000 MWh
And 45 000 MWh * 60 $/MWh = 2,7 Mil $ / yearSlide5
What is potential root causes for this elevated anode resistivity?
- The
root cause are cracks in anodes because all other properties are constant.Slide6
How can the root causes for the elevated anode resistivity be eliminated?
Forming over densititation.
Baking too fast - heat up rate
Mechanical cracks during transportation
Cooling
We can check all of this by measuring electrical resistivity.