Dry bottom ash handling system for Biomass to Energy Boilers

Dry bottom ash handling system for Biomass to Energy Boilers

The Ecobelt® BIO system

Patented for dry extraction, air cooling, and mechanical conveying of biomass bottom ash

Biomass power plants need a dedicated system to take care of bottom ash in a smooth, efficient, and sustainable manner.
Building on the extensive experience gained thus far in coal-fired power plants and Waste-to-Energy plants, Magaldi developed a customized solution for grate boilers burning any type of biomass.
Dependent upon the boiler layout and restrictions, the same system can also be used to convey grate siftings and fly ash from the hoppers located under the second and third boiler passes.

Water and related costs savings

With the Ecobelt® BIO system, bottom ash is cooled and conveyed in a completely dry way. Water is replaced with a stream of ambient air as a primary cooling medium. The result is the effective mitigation of the environmental footprint and a high reduction in operating costs since there is no need to dispose of or treat wastewater.

Increase in boiler efficiency

Waste energy - in the form of ash sensible heat and ash chemical energy - is recovered from the incomplete combustion of the bottom ash and introduced into the boiler as preheated air. This results in an overall increase in boiler efficiency, saving in biomass consumption, and CO2 emissions reduction.

High-quality, marketable ash

The absence of water greatly reduces ash disposal costs due to the significant reduction in ash weight.
Also, as a gainful alternative to landfilling, bottom ash can be sold to the cement industry because its features (dry and low in carbon) increase its saleability.

The Superbelt® conveyor technology

Apart from the overall benefits of dry over the wet system, the Ecobelt® BIO system offers compelling benefits that derive from the use of the Superbelt® conveyor applied to dry ash handling, including:
- high dependability
- high temperature resistance
- high impact toughness
- negligible wear and no tear issues
- low power consumption
- low and easy maintenance
- long service life.

Find out more about the Superbelt

Some successful stories

Italy

Dry bottom ash handling

Biomass power plant

Dry bottom ash handling

The Ecobelt® BIO system allowed to save approx. 4,600 m3/y of water, reduce bottom ash rate by about 4,000 tons/y and recover about 350 kWth of thermal energy from bottom ash.

The Customer
Power plant in Finale Emilia (Italy) burning 100% biomass through grate firing technology.

The Challenge
The Customer was looking for a reliable, environmentally friendly, and efficient bottom ash handling system (BAHS) for the new biomass power plant. That’s why, still in the bidding stage, the technical specification for the BAHS was changed from wet to dry, in favor of the Ecobelt® BIO system.

The Solution
Installed underneath a grate boiler, the Ecobelt® BIO extracts, cools and conveys bottom ash in a dry way. Bottom ash is then conditioned by using a small amount of water (not exceeding 8% of the total ash weight) to keep the dust down.
The Ecobelt® BIO system allowed to:

  • save approx. 4,600 m3/y of water;
  • reduce bottom ash rate by about 4,000 tons/y;
  • recover about 350 kWth of thermal energy from bottom ash, resulting in saving 1,100 tons/y of biomass and significant CO2 emission reduction.
Read more

Italy

Dry bottom ash handling

Biomass power plant

Dry bottom ash handling

The Ecobelt® BIO system has been able to secure the boiler performance and reduce O&M and ash disposal costs.

The Customer
The largest Italian operating biomass plant. It is fuelled by virgin timber, through a carbon-neutral process.

The Challenge
The plant was originally equipped with a wet system. From the very beginning, it had posed serious reliability problems due to sudden chain breaks, and the inability to transport big lumps, thus causing frequent boiler outages and forcing to reduce the boiler load. Additionally, the high water content in bottom ash resulted in large ash volumes and high disposal costs.

The Solution
The Ecobelt® BIO system has been able to secure the boiler performance (till now not a single instance of boiler outage attributable to our system occurred) and to reduce O&M costs as well as ash disposal costs thanks to the ash weight reduction due to the absence of water.

Read more