The main emissions from a flat glass furnace come from the combustion of fuel and the decomposition of the carbonate and sulphate raw materials. The raw materials are melted at a very high temperature so the process is extremely energy-intensive.
The most significant pollutants from a glass furnace are: nitrogen oxides formed from the nitrogen and oxygen in the air at high temperature; sulfur oxides from the refining agent
(and from oil fuel if that is used); and particulate matter derived from compounds volatilized from the molten glass. Carbon dioxide (CO2) comes from both the decomposition of carbonates and from combusted fuels.
We are tackling pollutant air emissions with a range of primary and secondary abatement techniques. Primary methods, such as special burners or carefully-chosen raw materials, including more cullet (recycled glass), reduce pollutant formation and can also improve the thermal performance of the furnaces. Secondary abatement removes the pollutants from the furnace waste gases before they are emitted through the chimney.
Novel pollution control plant installed at Ottawa
The abatement plant just installed on NSG Group’s OT1 furnace in Ottawa, USA, is a CCF unit purchased from McGill AirClean. The system is based on thousands of ceramic filters, in a single unit. Alkali is added to the waste gas and the resultant reaction products and primary particles are collected by the filter. The novelty of the process is that the fibers of the filters are coated with a metal catalyst so when the gases pass through the structure nitrogen oxides are also removed. It is expected that CCF technology will become the standard for new furnace pollution control plant throughout NSG group.