Fuel Preparation

Fuel preparation involves adjustment of the size and moisture content of the fuel, which is typically coal or petrocoke.  Vertical roller mills are the dominant choice for coal grindg with a share of around 90%. Ball mills, often used for fuels with poor grindability make up the remaining 10% (this infrormation does not cover the local Chinese market).  

increasingly, alternative waste and by-product streams – such as waste industrial oils and solvents, waste plastics, fractions of household waste, used tyres, wastewater treatment sludge and others – are being used in cement kilns as fuel. Some of these may require additional preparation infrastructure. More information on alternative fuels is available here

Fuel PreparationTechnologies & Measures

Technology or MeasureEnergy Savings PotentialCO2 Emission Reduction Potential Based on LiteratureCostsDevelopment Status
Optimizing Fuel Properties

Identical kiln systems fired by lignite and hard coal show a difference of around 0.1 GJ/t clinker. Reductions in the range of 0.3 GJ/t clinker are reported by using finely ground coal instead of coarse fuel.

Chinese flag If results similar to those in Europe are achieved, between 9 and 28 kg of CO2 can be reduced for every ton of clinker produced.

Costs of different fuels and necessary processing involved in preparation has to be taken into consideration.

Commercial
Vertical Roller Mills for Coal Grinding

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)

 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.

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)

Commercial
High-efficiency Separator/Classifier for Coal Grinding

1.7 kWh of electricity can be saved per ton of coal processed. 

indian flagIn India, savings between 1.0-1.7 kWh per ton coal have been realised, depending on the fineness of coal.

Chinese flag In China CO2 emissions can be reduced by 1.3 kg per ton of coal processed. 

Indian flag In India CO2 emissions can be reduced byAround 1.4 kg per  ton of coal processed. 

Installation costs are estimated to be US$ 0.01 per ton of clinker produced annually. 

In India, installation costs between US$ 0.2 - 0.4 million have been reported for this option. 

Commercial