Waste Heat Boilers

The temperature of the flue gases leaving the regenerator is usually between 300 and 600°C, and can be used to recover steam. Capturing the waste heat can be done before the flue gas cleaning (with subsequent cleaning) or after gas cleanup (Worrell et al., 2008. p.60). The amount of heat that can be recovered is dictated by the outlet temperatures, which is limited to around 200°C in order to avoid condensation on boiler tubes (IPTS/EC, 2013, p. 316). Produced steam can be used to generate power (using steam turbines), drive blowers or compressors, and/or preheat and dry cullet (Worrell et al., 2008. p.60).

The applicability and economic feasibility of the technique is dictated by the overall efficiency that may be obtained (including effective use of the steam generated). In practice, waste heat boilers have only been considered to recover residual heat downstream from regenerator or recuperator systems and there is thought to be at least two examples with oxy-fuel-fired furnaces in the EU. In many cases, the quantity of recoverable energy is low for efficient power generation and supplementary firing may be needed to generate superheated steam to drive turbines. Recuperative furnaces with higher waste gas temperatures or installations where it is possible to group the waste gases from several furnaces offer more opportunities for power generation. Waste heat boilers are in industrial use on some container glass facilities but most applications are with float glass furnaces (IPTS/EC, 2013. p.316). 

EU Flag

All float furnaces in Germany and many in other Member States have waste heat boilers (IPTS/EC, 2013. p.316).

 
Development Status Products
Commercial
Glass

Waste Heat BoilersCosts & Benefits

Parent Process: Melting and Refining
Energy Savings Potential

Between 1500 kWh/h (for end-port regenerative furnaces) and 6472 kWh/h for (side-port regenerative furnaces) can be recovered in container-glass production.

CO2 Emission Reduction Potential
Costs

Investment costs can exceed EUR 1 million with variable payback periods, depending on performance and prevailing energy prices.

Waste Heat Boilers Publications

Page Number: 

60

Waste Heat Boilers Reference Documents

Best Available Techniques (BAT) Reference Document for the Manufacture of Glass

As a reference of the EU Industrial Emissions Directive (2010/75 EU) this new version provides extensive information on Best Available Techniques (BATs) applicable to European Glass Manufacturing Industry for reducing environmental impact. The document is prepared by the  Institute for the Prospective Technological Studies of European Commission's Joint Research Center. 

Page Number: 

316-317