Vertical Roller Mills for Coal Grinding

Vertical roller mills (VRM) can replace ball mills or tube mills used for preparing coal.  Today VRMs with capacities up to 50 tph are the dominant technology for coal grinding. 

Chinese flag According to MIIT, grinding media wear in a VRM will only be 5 to 10 g/ton of coal powder, as compared to 100 g/ton of coal powder in a ball mill.

In China, as of 2010 use of VRMs for coal grinding had a market penetration of around 30%. During the twelfth five-year period, the market penetration of the technology is expected to be promoted to 70% (MIIT, 2012. p.20).

Development Status Products
Commercial

Vertical Roller Mills for Coal GrindingCosts & Benefits

Parent Process: Fuel Preparation
Energy Savings Potential

7-10  kWh of electricity can be saved per ton of coal processed  -  depending on the coal grinability charactertistics (Often determined by Hardgrove Gringability Index (HGI)

Indian flag 5-7 kWh/t coal savings have been realised in Indian plants. 

Chinese flagAs compared to ball mills, using VRMs in raw material preparation can reduce power consumption by 20 -35% (8 - 10 kWh/t-raw material). This transformation can also help reduce the abrasive material requirements (on a weight basis) and costs by 80% and 20%, respectively (MIIT, 2012. p. 19)

CO2 Emission Reduction Potential

 In China, the application of this technology can help reduce CO2 reductions by 5.5 to 8 kg per ton of coal processed.

 In India, the use of this technology helps reduce CO2 emissions by 4 to 6 kg per ton of coal processed.

Costs

Japanese flag Installation costs of  $14 million (1US$=110¥) are reported for a 200 t/h capacity plant in Japan, including cost of supplemental facilities.

Indian flag Installation costs between $4 million (for 30 tph capacity) and $8 million (for 100 tph capacity) - or between $80 000-135 000 per ton/h capacity - are reported in India. 

Operating costs vary depending upon the cost of power, wear rate of mill internals, type of fuel ground etc. The operating costs are estimated to be 20% lower than the tube mill, and 50% lower than ball mill.

Chinese flag In China, installation of a VRM for coal grinding would entail 10 to 20% more capital investment. However, savings due to reduced energy costs reduced wear of material will result in a payback time of 1 to 2 years (MIIT, 2012. p.19)

Parent Process:
Energy Savings Potential
CO2 Emission Reduction Potential

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Costs
Parent Process:
Energy Savings Potential
CO2 Emission Reduction Potential

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Costs

Vertical Roller Mills for Coal GrindingSchematic

Vertical Roller Mills for Coal Grinding Publications

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