Imerys offers Aurora™ to the power and steam industry. Aurora™ is a patented combustion-enhancing additive engineered to treat a boiler’s fireside system against the slagging, fouling and corrosion that occurs as a result of burning fuels high in volatile alkalis such as agro-waste, biomass, coal, MSW, pellets, wood and more.
Alkali metals sodium (Na), potassium (K), and calcium (Ca) found within these fuels are released into the flue gas as vapor. The vapor condenses onto fly ash particles and heat exchanger surfaces as liquid salts of sulfur, chlorine or similar particulates which in turn traps solid fly ash particles onto the cooler surfaces. Complex reactions then occur, including dissolution, sulfation, and sintering which ultimately leads to slagging and fouling. Aurora™ is an aluminosilicate that works as an alkali sorbent, capturing these alkali and alkaline earth metals and incorporating them into compounds which remain solid at boiler temperatures then exit the boiler as fly or bottom ash. Slagging, fouling and corrosion are therefore more easily managed or even eliminated.
By reducing slagging and fouling, Aurora™ increases boiler availability and increases overall boiler performance. Any remaining deposits are weakened and are more easily removed by conventional removal methods, thereby improving sootblower effectiveness, reducing maintenance costs and outage frequency. This effectively allows for the combustion of a mix of lower cost, opportunity fuels that are otherwise difficult to use, making it possible to increase boiler efficiency and power generation at a lower fuel cost.
Aurora™ is produced in three physical forms allowing flexibility and ease in application to the fuel prior to milling and combustion. Imerys has expertise in analyzing the fuel, recommending an appropriate dosage, and monitoring a variety of different boiler types to ensure that the product is added in the most technically efficient and cost-effective manner.
Other benefits include:
Reduced Maintenance Costs
AuroraTM can reduce maintenance costs due to the repair or replacement of equipment such as super heater pendants, corroded or eroded high-temperature tubes, and equipment damaged from falling slag. Fireside cleaning expenses including sootblowing, explosives and manpower are also decreased.
Increased Boiler Availability
The use of AuroraTM results in increased boiler availability due to fewer necessary repairs during forced outages and shorter planned outages.
Improved Heat Rates
Higher steam temperatures are maintained with fewer variations and power output is sustained by maximizing heat transfer.
Increased Fuel Flexibility
AuroraTM offers the opportunity for electric power plants to use lower quality, lower cost fuels in boiler operations. This fuel flexibility can lead to reduced fuel costs.