Ash handling systems are crucial for power generation, cement manufacturing, pulp and paper production, and waste-to-energy plants. These systems ensure smooth boiler operations, prevent blockages and maximize combustion efficiency. Beyond operational benefits, effective ash management significantly minimizes environmental impact by reducing emissions and promoting sustainable waste disposal. John Riley, leading expert in ash and materials handling gives insight into the current landscape, key trends, and future of ash handling systems.
How Ash Handling Works
The ash handling process begins in the furnace or combustion chamber, where fuel like coal, wood chips, biomass, or oil is burned. Ash produced here is managed through several stages:
- Economizer: Preheats feedwater, but ash can accumulate, requiring proper handling.
- Ash hopper: Collects ash at the bottom of the furnace for temporary storage.
- Conveying systems: Ash is transferred via water-based sluicing, mechanical conveyors, or pneumatic systems to a storage or disposal site.
- Ash Storage or Recycling: After the ash is collected and moved, it is usually stored in a designated ash silo or removed to an ash disposal site. Modern facilities often recycle ash for uses, such as cement and fertilizer production, contributing to a circular economy. An ash conditioning system is employed at the end of the process which includes a water spritzing system. This helps weigh down the ash and removes ambient dust circulation, preparing it for trucking away.
Efficient ash handling is vital for operational efficiency and environmental sustainability. Poorly managed ash systems can lead to equipment wear, operational inefficiencies, and regulatory penalties. Effective systems also support compliance with strict emissions and waste disposal standards.
Wet vs. Dry Ash Handling
Ash handling systems can be broadly categorized as wet or dry, each with distinct advantages:
Dry ash handling is preferred for facilities prioritizing sustainability and water conservation. These systems are costlier but reduce water dependency and simplify ash reuse. If you think of a campfire, you can compare the ash floating away from the fire to dry ash handling.
Wet ash handling uses water to manage ash, making it ideal for facilities handling large volumes of ash. However, water consumption and potential contamination can be environmental drawbacks. An analogy for this type of ash handling is throwing cold water on your campfire to extinguish the embers.
The choice depends on fuel type, regulatory demands, operational goals, and budget. Coal, with its high British Thermal Unit (BTU) value, generates more ash and often requires robust handling systems. Plants burning biomass or tire-derived fuel (TDF) may need specialized solutions to manage varying ash properties. John Riley, Material Handling Sales Engineer, explains it this way: “We have a system called a submerged drag, which is specific to a wet ash handling system, and then we also have our regular ash handling, which is a dry system. There’s an analogy I like to use to explain the difference.
Let’s say you are going camping, and you decide to build a fire. So you need to feed the fire to build it up, you put wood or paper into it, and then you notice some ash rising into the air. That would be the dry ash that we’re collecting. When done with the fire, you douse it by dumping water on the fire, this is an example of wet ash handling. The leftover ash is down in the bottom.”
Fuel Types
So in a boiler system, we’re feeding the fuel and burning the media, whatever it is. It could be wood or coal, or other mixtures as needed. Fuel feed fluctuates depending on prices. For example, oil or coal prices can get expensive, but coal is the best fuel type. You may throw tire-derived fuel into the mixture to help reduce costs. Although it’s more cost-effective, you do lose a lot of BTUs.
“Once the feed goes through the system, next is the submerged drag, and then the submerged ash that we’re pulling away, and lastly the fly ash that we’re collecting in ash handling,” explained Riley.
Did you know that a Biomass Fuel Boiler has Two Types of Ash?
- Bottom Ash which is collected from the Grate Hopper and Siftings Hopper
- Fly Ash which is typically collected from the Boiler Hopper, Air Heater, Mechanical Dust Collector, Baghouses, and Precipitator Hoppers
Understanding the output is an important component in a total system solution.
ProcessBarron’s Ash Handling System
For many plants, the mishandling of ash creates a messy system that requires labor-intensive ash cleaning, and processes. ProcessBarron’s ash conditioning system creates a much cleaner product.
The right equipment can save your business money and time. Custom ash handling solutions and equipment, as well as industry expertise, can help keep your business up to current standards and free up time for workers to spend doing more important activities. Our ash conditioning system is superior in the market. Our system includes specialized nozzle setups and a ‘doghouse’ roof design which allows for ash volatility management before it’s sent to trucks.
Process Barron’s systems are designed to comply with domestic regulations, including OSHA (Occupational Safety and Health Administration) and MSHA (Mine Safety and Health Administration) standards.
Ash Handling Systems
• Single Strand Drag Conveyors
• Dual Strand Drag Conveyors
• Screw Conveyors
• Ash Silos
• Fly Ash Conditioners
• Slide Gate Dampers
• Air Lock Feeders – Rotary Valves
• Double Flap Valves
Ash Handling System Leakage, Detection, and Plant Maintenance
The first step in detecting leakage in ash handling systems is visual inspection, looking for ash coming out at conveyor connection points, around covers, or areas with higher pressure in the system.
When leakage is identified, the typical plant response is to clean it up and monitor the situation. If the problem persists on an hourly basis, the plant may contact ProcessBarron for recommendations, potentially sending pictures or requesting an on-site inspection.
Process Barron’s ash handling systems have significantly improved plant cleanliness. Riley noted that in some cases, they can now leave a plant without their jeans being dirty, which was not the case 10 years ago.
Key Trends Shaping the Future of Ash Handling
Containment: The ash handling process has become more streamlined over time. Previously, it involved fly ash collection, scrubbers (to remove toxins like carbon), and precipitators. Now, the process often goes directly from the boiler to conveyance and storage, typically in silos, which are preferred over storage houses for better ash containment. We will continue to see a focus on ash containment ensuring that the ash pH balance is right before it is considered waste.
Efficiency: Drag conveyors are more energy-efficient compared to fan systems. While fan systems may require 10-200 horsepower motors, drag conveyors can accomplish the same task with 2-10 horsepower motors. The energy cost savings are significant, estimated at $615 per horsepower annually. This translates to substantial savings, with a 100-horsepower fan costing approximately $61,500 annually, compared to much lower costs for drag conveyors.
Sustainability: “Zero-waste” initiatives drive innovations like dry ash systems and air classification for ash reuse in construction or road building. Advanced ash disposal techniques shift toward a dry ash handling system and capture and store ash without excessive water use.
According to Riley, “There’s a trend towards smaller boiler systems, especially on the West Coast where power is at a premium. These systems often use alternative fuel sources such as sweet potatoes and almond husks.”
Waste-to-energy and circular economy: Ash is increasingly viewed as a resource, fueling energy generation or being repurposed into building materials. Specifically, pH balanced ash can be used for cement applications. Large poultry companies are using ‘chicken litter’ as a burn media, which produces a different type of ash but is still conveyed in the same way as traditional ash.
In the next 10-20 years, ash handling systems will likely achieve full sustainability, integrating seamlessly with renewable energy solutions. With growing markets for ash reuse and heightened corporate accountability, industries must prioritize innovative and environmentally responsible practices.
Get a straight line to the circular economy.
Technological Advancements in Ash Handling
Future trends in ash handling may include increased monitoring throughout the process, similar to current CO2 monitoring in fan stacks. Enhanced monitoring of ash composition, particularly for toxins, CO2, and SO2 (sulfur dioxide) levels, is expected to help expedite the process of determining how the ash can be used or sold. Offset your CO2 emissions without upsetting your entire system.
Challenges Ahead
“The primary challenge in ash management is containment during transportation from the boiler to storage units. Ash, being light and easily airborne, requires special handling to prevent environmental dispersal, necessitating enclosed systems such as contained drag conveyor units with top covers,” explained Riley.
Despite technological advancements, industries face hurdles like high initial costs, complex installations, and adapting to evolving regulations. Stricter emissions standards and the need for global standardization add to the challenges.
Partner with Us
Ash handling is more than an operational necessity; it’s a cornerstone of industrial efficiency. By working with ProcessBarron to embrace ash handling technologies and best practices, your business can meet regulatory demands, enhance efficiency, and be at the forefront of ash handling innovations. Find a ProcessBarron sales representative near you. Handle everything better with a total solutions approach.