475 Technical Solutions for Reduction of Waste Fuel Specific Emissions Flue Gas t reatment Innovative Technical Solutions for Reduction of Waste Fuel Specific Emissions in Cement Plants

481

Technical Solutions for Reduction of Waste Fuel Specific Emissions

Flue 

Gas T

reatment

Figure 7:   Thermal energy input of RDF in Austrian cement plants (except for grinding) for the 

time period 1988 to 2015 

Source:   Mauschitz, G.: Emissionen aus Anlagen der österreichischen Zementindustrie (Emissions from plants of the Austrian 

cement industry). Report. Vienna: Vienna University of Technology, 2016 

1.2. Energy recovery for RDF in cement kilns

A wide range of waste materials can be considered for energy recovery, having suitable 

input raw material properties because of their chemical and physical composition. What 

type of waste finally will be used in the kiln depends on different requirements, such as 

clinker production process specification and operating conditions, the raw meal and 

fuels composition, the feeding points, the off-gas cleaning systems, and the available 

waste amounts or the waste management structure in general [15]. 

Selected process conditions for the use of waste fuels in the clinker process can be 

summarised (acc. to [15]) as follows: 

•  maximum gas temperature of about 2,000 °C (main burner, flame temperature) 

and bed temperature of about 1,450 °C in rotary kilns,

•  gas retention time of about eight seconds at temperatures above 1,200 °C in rotary 

kilns,

10,000

Thermal energy input

TJ/y

Substitution of conventional, fossil fuels (2015): 76.1 percent

Total quantity of RDF (2015): 493,329 t y

-1

*Sawdust, waste wood, rubber waste, high caloric fraction, residues from agriculture, etc.

End-of-life tyres

SRF

Others*

Meat-and-bone meal

Waste oils

Waste solvents

Residuals from paper industry

9,000

8,000

7,000

6,000

5,000

4,000

3,000

2,000

1,000

198

8

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9

199

0

199

1

199

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199

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199

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199

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199

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199

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199

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199

9

200

0

200

1

200

2

200

3

200

4

200

5

200

6

200

7

200

8

200

9

201

0

201

1

201

2

201

3

201

4

201

5

0

Animal fat

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