Typical fuels do not contain ash but instead contain mineral matter which forms ash on combustion. The formation and chemistry of ash from biomass fuel however is dependent upon the combustion process, particularly to the combustion conditions. This, as well as the nature of the fuel burned, can have a massive effect on the quality and composition of your ash which can impact the efficiency and uptime of your boiler, waste disposal or re-use.

Generally, two types of ash are of interest – fly ash and bottom ash.

WHAT IS FLY ASH?

Fly ash is a fine material prevented from escaping to the atmosphere by a suitable abatement system such as bag filtration or electrostatic precipitation. These are typically contaminated with volatile trace materials, Dioxins and Furans.

WHAT IS BOTTOM ASH?

Bottom ash is the residue left under the grate at the bottom of the boiler and may contain physical contaminants mixed with the fuel such as metal, stones, glass, ceramics and other materials. It is coarser than fly ash and is typically contaminated with heavy metals.

HOW CAN FLY ASH AND BOTTOM ASH IMPACT MY BOILER?

Issues may arise when ash chemistry is present, including the promotion of corrosion or low ash melting., which leads to adverse impacts on boiler/plant efficiency, uptime and long-term material sustainability. This has a greater significance with some fuels than others and is particularly important when considering agricultural material or other biomass recyclates.

HOW CAN ALFRED H KNIGHT HELP?

As an industry-leading testing and inspection company, Alfred H Knight helps organisations around the world build an accurate and reliable profile of their materials. We support the biomass sector through a range of inspection and analytical services, including ash testing.

If you would like to speak to an expert regarding ash at your biomass power plant, get in touch today via our contact page. If you’re looking for more information on the range of services that Alfred H Knight offers to the biomass sector, head to our dedicated biomass page.