Known for its distinctive orange and black portable sawmills, Wood-Mizer Products Inc. has become a major leader in the U.S. sawmill industry. It is hoping to extend its influence into the emerging field of wood energy with its Bio-Mizer biomass furnace.
Bio-Mizer is an industrial grade biomass furnace (500,000 to 1 million BTU) that can produce heat for a sawmill, dry kiln, pallet operation, greenhouse, business complex or rural school. The first major installation is in conjunction with a new kiln at Fritch Mill in Snohomish, Wash. The April issue of TimberLine magazine carried a full feature on this installation.
Bio-Mizer burns at a fairly constant temperature creating an extremely efficient, clean combustion even while using a wide variety of biomass waste. It can burn sawdust, wood chips, agricultural waste, paper, and even chicken manure. The unit has advanced controls that can be operated remotely using the Internet or a smart phone.
Seth Baughman, the design engineer for the Bio-Mizer, talked with Pallet Enterprise about the research and development behind the Bio-Mizer. This article is a rough transcript of that interview.
Pallet Enterprise: Wood-Mizer first introduced the Bio-Mizer concept two years ago as part of its anniversary tour. How is this new industrial version different from the initial unit?
Seth: The basic concept is the same, but the unit that was demonstrated on the Wood-Mizer anniversary tour was much smaller. It was always our intention to do both a larger industrial-grade and smaller unit. We built several of the 150,000 BTU, which have been tested by a number of test sites over the last two heating seasons. In the future, we are going to take what we learned and apply it to the smaller unit, but for now we are focusing on the industrial unit demand.
Pallet Enterprise: Explain the evolutionary development of the Bio-Mizer biomass burner. Why did Wood-Mizer decide to expand into the biomass field?
Seth: Wood-Mizer first got involved with the whole concept of wood-fired biomass burners about ten years ago. At the time, we were doing research about developing a Stirling engine, which unlike a car has the heat source outside of the engine. We were going to use that to produce electricity. We needed a reliable heat source. That is where our first burner came from to provide a heat source for the Stirling engine project. We couldn’t make the Stirling engine cost effective enough, which is the same problem that people have been running into for decades.
We put the Stirling engine project on hold, and the burners were put on hold for a while too. Wood-Mizer’s primary market is the sawmill industry. Many of our customers have lots of sawdust, wood chips, and other forms of wood waste. The burner project resurfaced as a stand-alone product to help sawmills better utilize wood waste material. Over the past few years, we have been refining the design and getting it ready to go to market.”
Pallet Enterprise: What makes the Bio-Mizer biomass burner different from anything else on the market?
Seth: There are two processes with combustion. One is the gasification process, known as the primary burn that produces combustible gases. That is what you usually see as smoke. Smoke is the result of incomplete combustion. The biomass has been gasified but not the secondary burn. A lot of other burners only have a primary burn chamber so they only do the primary combustion part or if they have a secondary burn chamber to burn the combustible gases it adds cost to the system. Because we are using small particle size and suspending it in a vortex of high speed air, it allows us to do the primary and secondary burn in one chamber. It is very clean, simple and easy to use.
We have seen no major competitors that have done anything similar to our process. And the ones that we have seen out there can’t burn the range of fuels that our system can. Most other options can only burn sawdust and very dry sawdust at that. We are not exclusive in that technology but given how well we implement it, I would say that the Bio-Mizer is unique in the marketplace.
Pallet Enterprise: Why have you been able to make this single chamber design work when others have not?
Seth: A major advantage of our approach is the control side of the process. We have a nice big, LCD touch screen that is really easy to use. Our main electrical engineer and I spent a lot of time going over how we want the unit to operate in terms of tweaking the coefficients, as if we were there monitoring it all the time. The Bio-Mizer does all of that automatically.
You can monitor the system remotely. You don’t have to be right at the unit to control it. If you have a local area network, you can control the unit from there. The Bio-Mizer automatically sends text message or e-mail alerts if the system needs attention.
Pallet Enterprise: Why can you process such a wide variety of biomass types?
Seth: The Bio-Mizer deals with smaller particle sizes than many other burners. When you get down to smaller particle sizes, really all biomass becomes pretty similar. Most biomass is at 7,500 to 8,500 BTU per lb. in terms of energy content.
Obviously, there is a big difference between a tree branch and a corn husk in its normal state. If you grind material down to an inch or smaller in particle size, then it starts to work the same in terms of combustion. Although the process is still not easy to do, we have been able to get our feed systems and burn chamber to handle a wide variety of biomass types and moisture contents.
Pallet Enterprise: What type of process is needed to prepare material for use in the Bio-Mizer?
Seth: A hammermill would work fine. Right now we just offer a burner. But we are working on some grinders that specifically would work with the Bio-Mizer. Right now we are working with companies that already have fuel that fits our criteria. We take anything from dust particle size to material that will fit through a one-inch screen.
Pallet Enterprise: One of the potential uses of the Bio-Mizer is electricity production. Is anyone doing that right now?
Seth: No customer is using the Bio-Mizer to produce electricity. We are currently talking with several companies in order to bring that to market for industrial applications.
Pallet Enterprise: Explain how your system produces heat energy?
Seth: Our heat exchanger transfers heat energy from the hot combustion of gases into water, which is known as hydronic heating. This process has been around for centuries. It’s a known heating system. A lot of facilities already have hydronic heating systems in place.
Hydronic heat offers a number of advantages. It is easy to transport over long distances because you can run it in installed pipe. It is a lot more comfortable in terms of heating a living/working space compared to forced air heat.
Pallet Enterprise: One of your first major installations is an integration of your burner with a new dry kiln. Describe how the Bio-Mizer is being used in this application.
Seth: It pretty much depends upon whether the kiln is set up to run off of steam or hot water. If the kiln is set up to run off hot water, all you have to do is unhook your current heating system and hook ours into it. If you’re running steam, you will have to add some more radiators to dissipate heat because it takes more surface area to transfer the same amount of heat at a lower temperature and obviously your hot water is at a lower temperature than steam would be.
Pallet Enterprise: What type of space requirements does the Bio-Mizer have for a basic installation?
Seth: The unit can be set up in a couple different configurations, depending on what arrangement works best at your facility. It can be set up in a compact arrangement with a footprint of 22’ x 25’, or in a linear arrangement requiring 11’ x 35’.
Pallet Enterprise: What makes for an ideal location to run a Bio-Mizer system?
Seth: The biggest thing we look for is your fuel supply and how much of it that you generate or have on hand. If you are running a system 24/7, it does take a lot of wood waste. You can burn a couple tons per day pretty easily. You have to make sure that the fuel is the right size and moisture content too. The Bio-Mizer can process material ranging from zero to 60% moisture content.
Another major consideration is whether the unit will be appropriately sized to your heat load. If you will need more than one million BTU, we can either sell you multiple units or can have a supplementary heat system.
When a kiln is up and running in the middle of a cycle, the heat draw will be a lot less than when you are first starting up. Some users will run our unit and a supplementary gas burner just to bring it up to temperature. Once it hits that temperature, the gas burner will shutoff and our system will continue to run. You want to make sure that you have enough heat load as well. If you don’t have a big enough heat load, then you are just burning fuel for no reason.
Pallet Enterprise: Describe the entire Bio-Mizer process from start to finish. What are the primary components of the system? {See accompanying chart}
Seth: The three main components are the fuel bin, the heat chamber and the heat exchanger. Bulk fuel is stored in the fuel bins. It runs when the burner is on and needing fuel. It has an auger that undercuts the entire pile so that you don’t have any bridging problems. A conveyor takes fuel into a metering bin, which serves to precisely control the amount of fuel fed to the burner. This keeps fuel flowing to the burner at consistent rates.
At the bottom of the metering bin is a six-inch auger that is run by a variable speed drive. The computer controls the rate of fuel fed into the burner by adjusting the auger speed. Fuel is dropped into the top of the chamber and gets suspended in a vortex of air. There is a combustion blower down at the bottom of the burn chamber. The fuel is burned while in suspension.
Hot gases exit up to the flue at the top. If there is no call for heat, then it will just vent to the atmosphere. If there is a call for heat, then the gases get drawn across into the heat exchanger.
The Bio-Mizer uses a double-pipe, counter-flow heat exchanger. It uses two pipes that are concentric. Combustion gases go through the inner pipe, and in the space between the two pipes the water flows in the opposite direction of the combustion gases. Water flowing in the opposite direction picks up heat. From there, the hot water goes to the hydronic manifold which conveys heat energy to the kiln or other device.
Pallet Enterprise: Tell me a little about the gases emitted by the Bio-Mizer burner. The emission of harmful gases has been a concern for some gasification processes. How does the Bio-Mizer compare to other units?
Seth: CO2 is the primary gas emitted by the Bio-Mizer. Any time you are combusting a hydrocarbon, CO2 and water are going to be your main emission. Our levels of harmful gases, such as carbon monoxide and various NOx gases, are extremely low.
Smaller home units have been banned from some localities due to emission concerns. The entire state of Washington doesn’t allow them any more because they don’t burn clean enough. The Bio-Mizer system doesn’t have that problem at all. There are no visible emissions and even invisible emissions are extremely low.
Pallet Enterprise: What are the top advantages of the Bio-Mizer?
Seth: The biggest advantages of the Bio-Mizer unit are the low emissions, the user interface, remote control, the range of fuels.
The one other thing that I have yet to mention is a built-in igniter. When the system is first turned on, the Bio-Mizer uses an igniter to get the chamber up to temperature before we start introducing the biomass fuel.
The igniter is actually rated for the full output of the unit. If you ever have a critical application where you need the heat and have an interruption in your biomass supply, you would be able to run it off the igniter for the full heat capacity of the system. You wouldn’t be without heat. It is nice to know that you have a backup in case the wood supply is disrupted.
Pallet Enterprise: What types of green energy credits or government funding exist that could help offset some of the cost of a Bio-Mizer?
Seth: Wood-Mizer has done a lot of research on the availability of government assistance and funding. There are quite a few grants and other economic incentives available. Most are at the state or local level. We encourage anyone who is interested in a burner to call our representatives. They will help you determine what might be available in your area.
Economic incentives that we have uncovered are mostly in terms of grants that cover most if not all of the costs of the system. Grants and other funding sources can significantly reduce the cost of the unit.
Pallet Enterprise: One of the major benefits of the Bio-Mizer is its ability to utilize a wide range of fuel sources. Are there any mechanical changes that must be made to switch fuel types?
Seth: Generally, the small particle size means you don’t have to make lots of changes when switching from different fuel materials. But let’s take an extreme example. If a user wants to switch from molder shavings, which are very light and fluffy, to corn, which is very heavy and dense, then you are talking orders of magnitude difference in terms of energy density. You may have to change out a drive sprocket to alter the speed of the fuel feed auger. But for anything other than extreme differences, the variable speed auger will be able to account for various fuel types.
Pallet Enterprise: Explain the economics behind the Bio-Mizer. What is the payback period?
Seth: A big driver in terms of calculating the payback period is the cost of the existing fuel source. A year ago energy prices were sky high and a lot of times we calculated the payback period was less than twelve months, especially if it was being used heavily. Right now, the payback is a little longer than that, but we still have a lot of volatility in the energy markets. Who knows how long the fuel markets will be will where they are now.
Despite lower fuel costs, the Bio-Mizer still offers a decent payback period. With the political climate the way that it is, there will be even more incentives becoming available to encourage green energy – grants, tax credits, etc.
Pallet Enterprise: Why does this product make sense now?
Seth: A lot of people are realizing that we need to take care of the environment. The Bio-Mizer uses material that may otherwise go to waste. It displaces fossil fuels. The net impact is positive for the environment.
Many of the places where the Bio-Mizer makes sense are facilities that have significant amounts of unused fuel material. For some companies this amounts to free fuel.
Pallet Enterprise: What are a few really unique applications besides a sawmill or dry kiln?
Seth: Pallet companies, industrial buildings, greenhouses, chicken farmers. With the recent push for biofuels, one of the most prominent sources of biodiesel is algae. The advantage of using the bio-mizer for that is the fact that you must keep the algae warm to make it grow. That’s where the heat comes from. After you harvest from the algae at the end of the process, you are left with all this empty algae husks that isn’t really good for anything. You can burn the leftover algae to produce heat and the CO2 required to grow algae in the first place.
Pallet Enterprise: What is needed for site prep and installation?
Seth: You need a flat and level concrete slab. The fuel bin needs to be at least under roof if not in a building. You don’t want it to get rained on. You will be hooking to an existing hydronic system or add one. You need hookups for the propane for the igniter. The igniter is available in propane, natural gas or fuel oil. The electrical requirement is 220 volts single phase, 45 amps service.
Pallet Enterprise: What is the typical installation time for a Bio-Mizer system?
Seth: From the time the unit arrives, it should only take three guys two days to assemble.
Pallet Enterprise: How does ambient temperature impact performance?
Seth: The biggest problem we run into in terms of the ambient temperature is when you get below freezing if you are using a really wet fuel. Many times guys will want to burn sawdust directly off the saw so that it hasn’t been dried. You get a chunk of sawdust ice. It is more of a feed problem than anything else. Even then, that only happens if you are between runs and the unit has been sitting idle for a long period of time, and you are trying to start it up when the temperature is below freezing. This really isn’t a problem if it runs continuously.
Pallet Enterprise: How is the Bio-Mizer carbon neutral?
Seth: If you have a pile of biomass sitting there, it is going to decompose over time and produce CO2. All we are doing is essentially speeding up the process by burning it. We are releasing the same amount of CO2 into the environment as allowing it to decompose. It is carbon neutral in that sense. And when you take into account, the fact that by burning the biomass instead of fossil fuels, we are reducing the net carbon emissions. You can actually think of it as a carbon negative process.
Bio-Mizer Offers Innovative Features for Its Biomass Furnaces
• The Bio-Mizer Model 1000 is a biomass furnace that can efficiently utilize a wide range of biomass waste products, like sawdust, wood chips, and paper, as well as agricultural and animal waste to produce environmentally friendly, clean, and safe heat for a variety of industrial applications.
• Is designed to meet the heating needs of industrial applications with heating demands ranging from 500,000 to 1,000,000 BTUs. This stand-alone system can be used to replace an existing fossil fueled furnace or be engineered into new heating systems.
• State-of-the-art controls allows for remote operation. It continuously monitors over a dozen critical variables in the burning process hundreds of times per second to precisely adjust each component. You can monitor the performance of your furnace from virtually anywhere via smartphone or PC, or opt to receive a text message on your phone when your furnace needs fuel or attention.
• The Bio-Mizer has the ability to utilize fuels with relatively high levels of moisture content. The furnace is designed to burn off excess moisture before the fuel enters the heart of the burn chamber and releases the moisture in the form of steam.
• The Bio-Mizer has the ability to operate on fuels with up to 60% moisture content, which may not be a suitable fuel source for other furnaces.
• The cyclonic burn process is the result of ten years of research and testing.
• Safety features prevent run-away or overheating conditions.
• All steel structures in the burn chamber are protected from the heat by a 4 ½” thick firebrick and custom ceramic insulators.
• Heat exchanger features a variable speed blower to control the process of accurately transferring heat from the burn chamber to 100 gallons of water flowing through transfer pipes in the exchanger. The Bio-Mizer’s heat exchanger utilizes a refined counter-flow process to transfer heat from combustion air to water for greater efficiency.
• Low emissions.
• Automated ash removal.
• Bulk storage and feeding system capable of dispensing various fuels.
