Waste-gas heat recovery by Thermo-Chemical Recuperation

HyGear, CelSian and the National Committee Netherlands Glass industry have their hands joined to develop a Thermo-Chemical Recuperation system to decrease the energy losses of the glass furnaces.

Industrial glass furnaces produce between 50 to 800 tons glass per day, 365 days of the year. In many cases natural gas is used as a source to heat the furnace. Unfortunately, a large amount of the energy supplied to the furnaces is lost through flue gases. Moreover, in the glass production process the energy consumption accounts for about 15% of the total glass production costs. This means that by reducing energy consumption, costs will also be reduced. The Thermo-Chemical Recuperator (‘TCR’) will save energy and therefore costs, by re-using the furnace’s waste gas heat to convert natural gas, water and waste heat into a high calorific reformer gas mixture.

The TCR can be applied in oxy-fuel furnaces, recuperative furnaces and hybrid regenerative/recuperative furnaces. Highest energy savings are expected in recuperative furnaces, but highest cost savings are expected for oxygen-fired furnaces, saving natural gas and oxygen at the same time. The principle of the system is displayed in the figure below.

Waste-gas heat recovery by Thermo-Chemical Recuperation

First, flue gas heat is used to generate steam from water. This steam and desulfurized natural gas are mixed and further heated. When the mixture reaches a temperature level of 700-900 °C, it is exposed to the catalyst in the reformer. In the reformer a mixture of hydrogen and carbon monoxide, so-called synthesis gas (reformer gas or syngas), is formed by the following endothermic reaction:

CH4 + H2O  -> 3H2 + CO

The hot syngas has a higher energy content than natural gas. Natural gas is added to the hot syngas and the new fuel mixture is fed to the furnace. Using the TCR, less natural gas is needed to melt the same amount of glass. Furthermore, since the oxidation of syngas generates more heat than natural gas, the total amount of fuel is reduced and thus also less oxygen needs to be used. Currently, oxygen is obtained with an energy intensive process and therefore expensive. The TCR technology will be beneficial for almost all glass plant, but the largest economic benefits are expected for oxy-fuelled furnaces.

Information about project partners on www.celsian.nl and www.icglass.org.

If you would like to receive more information about the Thermo Chemical Recuperator, please contact Ms. Viola van Alphen (HyGear) at viola.van.alphen[at]hygear.nl or Mr. Hans van Limpt (CelSian) at hans.vanlimpt[at]celsian.nl




HyGear: The Global Hydrogen Source

HyGear: The Global Hydrogen Source