FAQ’s on Air Curtain Burners

Since the invention of fire, man has been using burning techniques to clean up his messes and to clear land for future productivity. More recently, technological advancements have transformed the arduous and ineffective process of burning slash piles, construction waste, yard waste, storm damage clean-up and more.

Taking this new technology and pairing it with a mobile burning system, the craftsmen at Air Burners, Inc.®manufacture a machine that can handle even the biggest waste wood clean-up jobs with ease. This technology, called Air Curtain Burners, has taken controlled burning to a new level.

We’ve asked the pros at Air Burners to answer your questions about their advanced technology burning systems.

What is an air curtain destructor?

An air curtain destructor, or air curtain burner, uses advanced technology to burn wood waste in an efficient manner. Available in a few different models, air curtain burners are mobile and efficient machines that can aid in everything from disaster clean-up to construction disposal.

What is the purpose of an air curtain burner?

The primary purpose of an air curtain burner is to reduce the particulate matter (PM) in the air that is released from a controlled burn. Black carbon is a known pollutant, and the air curtain burning system reduces the amount of particulate matter in the air through the system of controlling the smoke and burning it a second time.

The secondary purpose of an air curtain burner is to improve the efficiency of burning environmental waste. This is a cost-effective solution for the issue of disposing of wood materials.

How does it work?

A fire is started in the FireBox™ using an accelerant, such as diesel fuel. After it has grown in strength, usually about 15-20 minutes, the air curtain is engaged. Using a steady stream of air, the air curtain machine directs smoke back down and into the fire, causing it to burn a second time. This reduces the particulate matter to acceptable U.S. EPA guidelines. By controlling the air flow, the fire is more efficient, burns more thoroughly and steadily, and has less particulate matter output.

What are the advantages of using an air curtain burner machine?

The primary advantage to using the air curtain burner is having a much more efficient method of disposing of waste material. When a lot of material needs to be burned in a short amount of time, there is no better method than using the air curtain burner. 

Secondly, it is the best way of controlling the amount of pollution that is released during a burn. The same amount of material, placed in a landfill, would take up an enormous amount of space and would take years to break down. Burning is an environmentally-friendly solution.

Also, air curtain burning is cost-effective. Burning onsite saves money on grinders and trucks. And air curtain burners dispose of tonnage much faster than open burning, saving labor costs. In addition, the  PGFireBox® is designed to generate electricity from the burning wood. This electricity can then be used onsite to run machines producing biomass products like biochar, wood pellets or mulch, saving on operating expenses. Another consideration is the fact that ash can be sold to nurseries or agricultural facilities, which is both a financial and an environmental advantage.

Finally, the air curtain burner reduces the amount of the tiniest particulate matter, called PM2.5, from being released into the air. These particles are under 2.5 microns in size and are small enough to get past your body’s defenses. 

What are the disadvantages of using an air curtain burner machine?

The air curtain burner needs balance to work effectively. It requires an air curtain that has a mass flow and velocity in balance with the potential mass flow and velocity of the burning waste. If the air curtain velocity is too high, the FireBox™ can become over-pressurized which can lift the curtain higher, causing it to be less effective in controlling the smoke. Embers and ash can also be blown out of the FireBox™. 

However, if the mass flow of the curtain is too low, the unburned particles in the original smoke may penetrate the curtain because of the hot gases being generated from the burning material.

Ash should be cleaned out at the beginning of each day. Ash needs to be excavated out of the box every time it reaches three feet deep. Operators must wear proper breathing apparatuses as protection.

FireBoxes™ do not prevent embers from escaping during the burn or during removal of ash, so if you are burning in a high danger fire zone, additional precautions must be taken to guard against wildfires.

What is left after air curtain burning?

Clean ash should be your final product. This can be turned into the earth for proper disposal or can be sold to area horticulture facilities. A certain amount of biochar, a desirable form of charcoal, will be present in the ash.

How long does it take to activate the air curtain burning system?

When you first start burning, the fire needs to grow in strength for 15-20 minutes before the air curtain can be activated. After that, it can burn without stopping, except for ash removal.

How fast can you load an air curtain machine?

The rate of loading needs to be in balance with the rate of burning. Since the burning rate will be steady and much faster than open burning, the rate of loading can also be steady and faster.

How can I reduce pollution from a burn?

If you are concerned about black carbon or particulate matter from your burns, an air curtain burner machine, such as the FireBox™, is a great solution. You can end up with a very clean burn, with opacities well under 10% per EPA Method 9 Testing, as compared to open burning, which typically can run at 80% to 100% opacity. 

How many tons can be burned in an hour?

Our smallest machine can burn 1 to 2 tons per hour. Our largest machine can burn over 10 tons an hour.

Is there a limit to how long you can keep a burn going with an air curtain machine?

The machine can run as long as needed to get the job done. The operator can continue adding fuel at the same rate that it is burned. After 3’ of ash is built up—approximately 20 hours of burning—the ash must be cleaned out to maintain the efficiency of the burn rate.

Do air curtain burners run on diesel?

As of model year 2019, all our machines are equipped with Tier 4 final diesel engines as required by the US EPA. The S-series FireBoxes can also be fitted with electric motors in lieu of diesel engines. For more details, additional information can be requested here.