Bottom ash handling and fly ash handling

Bottom Ash Handling and Fly Ash Handling

In power plants and industrial boilers, ash is generated as a byproduct of the combustion process. Proper handling of bottom ash and fly ash is critical to ensure smooth operations, environmental compliance, and efficient resource management. Here’s a detailed overview of both systems:

Bottom Ash Handling

Bottom ash is the coarse, heavier ash that falls to the bottom of the boiler during combustion. It often contains slag, clinkers, and unburned material.

Common Systems for Bottom Ash Handling

1. Submerged Flight Conveyors (SFC):
   • Hot bottom ash falls into a water-filled trough.
   • A flight chain system drags the ash to a dewatering section for disposal or further processing.
   • Ideal for continuous ash removal.
2. Dry Bottom Ash Handling Systems:
   • Ash is cooled by ambient or forced air instead of water.
   • These systems conserve water, reduce operational costs, and improve ash quality for reuse (e.g., in cement production).
3. Hydraulic Systems:
   • Ash is hydraulically transported from the furnace to a settling tank.
   • Requires significant water usage, now less favored due to environmental regulations.
4. Mechanical Conveyors:
   • Drag chain, belt, or screw conveyors transport the ash without water.

Advantages of Modern Bottom Ash Handling Systems:

• Minimized water usage (or complete elimination in dry systems).
• Reduced operational and maintenance costs.
• Environmentally friendly with better ash quality for reuse.

Fly Ash Handling

Fly ash is the fine, powdery material that is carried with the flue gas. It is collected by pollution control devices such as electrostatic precipitators (ESPs) or bag filters.

Fly Ash Handling Systems

1. Pneumatic Conveying Systems:
   • Dense-Phase Pneumatic Conveying:
     • Transports ash at low velocity to reduce wear and energy usage.
   • Lean-Phase Pneumatic Conveying:
     • Moves ash at higher speeds over shorter distances.
2. Mechanical Systems:
   • Uses screw conveyors, belt conveyors, or drag chain conveyors for short distances.
3. Vacuum Systems:
   • Utilizes negative pressure to collect fly ash from ESPs or bag filters and transport it to silos.
4. Ash Storage and Disposal:
   • Collected fly ash is stored in silos for recycling (e.g., in construction) or transported to disposal sites.

Advantages of Efficient Fly Ash Handling:

• Enclosed systems prevent dust emissions.
• Supports fly ash recycling and reduces disposal needs.
• Complies with stringent environmental regulations.

Key Differences Between Bottom Ash and Fly Ash Handling

Integration of Bottom and Fly Ash Handling Systems

A complete ash handling solution integrates both systems seamlessly to ensure continuous and efficient removal of ash. Advanced systems include features like:

1. Centralized Control Systems:
   • Real-time monitoring and control of both bottom and fly ash systems through SCADA or PLC systems.
2. Ash Dewatering Units:
   • Reduces water content in bottom ash for easier handling and transportation.
3. Silo Storage Systems:
   • Fly ash and bottom ash can be stored in separate silos with dust suppression systems.
4. Ash Recycling Units:
   • Bottom ash and fly ash are processed for reuse in construction, road base materials, or other industries.

Environmental Compliance

Both systems must comply with regulations such as:

• Limiting particulate emissions (e.g., from fly ash).
• Reducing water usage and wastewater discharge.
• Ensuring safe disposal of ash residues.

Modern dry ash handling systems have become the industry standard to achieve environmental sustainability.

Applications of Bottom and Fly Ash

1. Bottom Ash Applications:
   • Aggregates for construction.
   • Raw material in cement and concrete production.
2. Fly Ash Applications:
   • Fly ash is widely used as a cement additive (a substitute for Portland cement).
   • It is also used in road base stabilization, bricks, and tiles.

If you’d like assistance designing or improving a bottom ash or fly ash handling system, I can guide you with technical options and solutions tailored to your plant’s requirements! Let me know how I can assist.

Bottom and fly ash handling

• Bottom ash cooling screw
• Ash conveyors
• Bottom ash screen for sand recycling
• Ash container
• Fly ash cooling screw
• Pneumatic conveying systems
• Fly ash silo
• Dry and wet discharging systems

Features of the ash handling system

• Wide capacity range
• Wide cooling range
• High uptime with rugged, proven design

Drag Chain Conveyor is a conveying device for continuously conveying powder, granules and small pieces of granular materials in a closed casing by means of a moving scraper chain. Since the scraper chain is buried in the material to be conveyed, it is called a buried scraper conveyor. When transporting horizontally, the material is subjected to the thrust of the scraper chain in the running direction. The material is conveyed forward with the scraper chain to form a continuous overall material flow.
Drag Chain Conveyor is widely used in metallurgy, building materials, power plants, grain, mining, food and other industry.

General Technical Parameter:

1. The traction chain has high strength and can be used for long distance transportation.
2. Processes such as sorting, drying, cooling or assembly can be performed during the transport process.
3. Drag Chain Conveyor is simple structure,light weight,small volume and floor space. Easy to produce, install and maintain.
4. Flexible layout, horizontal or incline conveying materials can be realized. Continuous operation, multi-point feed and discharge.
5. Conveying airtight, dustproof, anti-virus, explosion-proof. Ambient temperatures of -20 to +45 °C.
6. Drag Chain Conveyor is widely used in conveying powdery and granular materials, and can realize multi-point feeding and multi-point unloading.
7. The Drag Chain Conveyor is reasonable in design, simple in structure, and small in cross-section, which can reduce the installation space.