Mixing of biogas with natural gas for the direct usage in boilers
Gas mixing device at a beer brewery. 125m3/h biogas
Biogas can be used not only for electricity or biomethane production, but also directly in boilers, for example, at distilleries, breweries, and fruit- and vegetable- processing plants. This method is economically most attractive and requires the least capital investment. Customers often ask how to use biogas in the existing boilers and whether a burner replacement is necessary.
If biogas is mixed with natural gas and the natural gas consumption exceeds the biogas consumption, the burner replacement may not be necessary. What is essential is the proper gas mixing. Zorg was one of the first to use a Venturi-type device at a brewery in Chisinau, Moldova. 125 m³/h of biogas coming from a WWTP treatment plant is mixed with natural gas in a ratio of 1:10.
In principle, biogas and natural gas are the same type of fuel. The same burners and boilers used for natural gas are also used for biogas. But biogas has a lower calorific value, so its consumption is higher than natural gas. The diameters of the burner inlet pipes are larger for biogas. With significant biogas volumes and complete replacement of natural gas with biogas, if the burners and boilers have a 30-40% reserve, then replacing the boiler or burner is not necessary. However, if the boiler does not have a reserve, a decrease in boiler output will be observed when switching to biogas. In this case, either the burners or the boiler itself will need to be replaced.