5 Benefits of Air Curtain Destructors

Whether you are looking to clear land for construction purposes, perform forest fuels management or wildfire rehabilitation, or support natural disaster recovery operation, you’re going to need to dispose of the wood waste you’ll generate in the process. While conventional wood waste disposal methods, such as open pile burning and biomass-to-energy plants, may be popular, they have their limitations. For example, open burning results in considerable air pollution, and biomass-to-energy or cogen plants are few in numbers and can only reasonably accept wood waste from within a 50-mile travel zone. 

Enter air curtain destructors also called air curtain burners or FireBoxes. Above ground air curtain destructors leverage air curtain technology to burn wood waste in a well-designed machine for a cleaner and faster burn. Read on to learn the top 5 benefits of air curtain burners relative to conventional wood waste disposal methods.

1. Reduced particulate matter emissions into the environment

When wood waste is burned in an open fire, the particulate matter or smoke produced is freely allowed to disperse into the air. Not only does this give rise to environmentally detrimental air pollution, it is also a potential hazard to human health.

This is because particulate matter of less than 2.5 microns in size, or PM2.5 particles, can get embedded in your lungs when breathed in. Prolonged exposure to such PM2.5 particles may lead to increased risks of contracting lung cancer or heart disease, and hence premature death, over time.

However, air curtain destructors – like those available from Air Burners – generate an air curtain designed to trap particulate matter as it rises from burning wood waste. The air curtain traps the particulates just below the air curtain where they tend to bounce back from it, until they are re-burned in the hottest zone just below the air curtain and broken down further until they are small enough to pass through the air curtain and become visible above as “heat waves”.

The resulting burn is very clean, with plume opacities of below 10% per EPA Method 9 Testing. This can be contrasted with open burning, which may produce smoke plume opacities of between 80% and 100%.

2. Produces environmentally friendly biochar that can be sold for a profit

When wood waste is burned in an air curtain destructor, the residual wood ash collects in the bottom of the burn chamber. The ashes should be removed daily, best first thing in the morning. The residuals usually include a fair amount of charred wood, wood chunks that did not combust completely and were starved of oxygen, because they were self-insulated by the ashes. This triggers the process of pyrolysis, or the burning of wood in the absence of oxygen, which produces a porous, carbon-based substance known as biochar. This biochar is a byproduct of the air curtain burner’s operation whose primary task is to get rid of massive amounts of wood waste in a clean and efficient manner.

Biochar is a rich, natural soil amendment. When biochar is added to the soil, it increases the soil’s ability to retain nutrients and water and thus its viability for growing crops. With such agricultural benefits, biochar is in high demand and is relatively easy for air above ground air curtain destructor users to obtain. They simply need to hose remaining unburned wood chunks with water and filter the material through a screen. The resultant biochar can then be sold into the market for a profit. Air Burners’ customers have reported making as much as 10-15 cubic yards of biochar daily, with a 1 cubic yard bag going for as high as $120.

While biochar on a smaller scale can also be produced by other methods, such as using burn barrels and open pile burns, that process may be much more labor-intensive. Though the steps are fairly comparable, the big difference is the environmental friendliness of air curtain burning in contrast to the other more rudimentary combustion methods. The latter create serious pollution and would have difficulty getting air permits, if at all, for any commercial-scale operation. 

3. Burns wood waste within a quicker period of time

In a self-contained air curtain destructor, fire temperatures can reach 2,000°F or more. At the same time, the high velocity of air being the pollution control feature of the machine also directs a small portion of the air into the FireBox for over-oxygenation of the fire. This helps create high temperatures that result in a faster and cleaner burn.

In contrast, fire temperatures tend to be much lower for open pile burning. As a result, the wood waste will take longer to burn away, and it also requires handling throughout to keep the fire from slowing down. We know this from our experience with campfires or fireplaces: you must stoke the fire to keep it up.

For example, it was recorded that it took a couple of hours to burn a 20-ton pile of wood waste in our Air Burners FireBox Model S327, compared to open pile burning another 20 tons of wood debris nearby which took nearly 48 hours to go away, smoking terribly all along. There was hardly any visible smoke above the FireBox throughout the burn period.

4. Lower preprocessing costs compared to typical biomass-to-energy schemes

The conventional method of converting biomass to energy is a resource-intensive exercise that involves high capital and recurring costs and is limited in scope. To burn biomass, you typically need to first process the whole wood waste in a grinder. The grinder may consume 30 to 40 gallons of diesel per hour and usually a second pass is required to make the resultant chips acceptable to the waste-to-energy plant. This process is also highly polluting from the large diesel engines used.

On the other hand, the PGFireBox biomass-to-energy system offered by Air Burners is a whole-log burner. It bypasses such energy-consuming grinding processes. This is because PGFireBoxes have been designed to accept whole wood waste, without the need for grinding.

PGFireBoxes are also portable, allowing them to be moved and set up closer to the site requiring wood waste disposal. As a result, less diesel needs to be used to transport wood waste for incineration. This reduces preprocessing costs, resulting in a far more economical and cleaner method of disposing of wood waste and making energy from it.

5. Safer deployment in a greater range of weather conditions

As open burning involves the burning of wood waste in an open area, success often depends on the weather. On days with high wind speeds, open burning may pose a high fire risk and hence cannot be done safely.

Employing an air curtain FireBox can overcome to some extent such weather obstacles. Air curtain destructors burn wood waste within a contained unit, making their operations less subject to weather conditions, although their use is also not recommended when wind speed exceeds a certain MPH as outlined in the respective operating manuals for the machines. However, FireBoxes can be fitted with an option called an ember screen. It is deployed at the end of the workday to ascertain that embers that might be left in the air curtain burner would not escape, should weather conditions worsen overnight.

Disposing of wood waste using an air curtain destructor

With their environmental friendliness and greater efficiency in wood waste disposal, air curtain destructors are the only reasonable option compared to other wood waste disposal schemes, especially open pile burning.

At Air Burners, we offer an entire range of air curtain burners that can help meet all your wood waste disposal needs, large and small. Lease financing options are also available through third-party financing institutions.  Contact us for a quote today.