As you know, installing a biomass boiler is a significant undertaking. For this reason, it is crucial to carefully consider various factors before proceeding with the project to ensure the best possible result. To help you make an informed decision, here are the five most important factors in your biomass boiler installation.
This is the most crucial question to ask first as it has the largest impact on the economics of a project. If you are a company generating wood waste on site, like a kitchen manufacturer, or you are in logistics and have tons of broken wooden packaging every week, this is your answer. Self-suppliers of fuel will always have the cheapest fuel stock because the fuel is effectively free or they might be paying to get rid of it.
Customers without enough fuel onsite need to bring it in. There are many biomass providers in the UK, Ireland and the EU. There are also providers in North America now. The cost of the fuel will vary largely on the local logistics in your area. Some areas will have energy costs of 1p/kWh, whereas in some places, pellets can cost 14p/kWh. It really depends on the situation.
This is related to the first question. Your fuel type will depend on the biomass available. If you are a Tequila manufacturer in Mexico, bagasse from the cactus plant will be available. As a kitchen manufacturer, you will have chipboard and MDF dust to burn. You must ensure the biomass boiler you install has the correct fire chamber to deal with the available fuel. It is not just the fire chamber that needs to be right. The storage, conveying and flue gas cleaning systems must also be suitable for your fuel.
Pellets and MDF dust are very different products and require different machines to burn. However, industrial wood waste burners can generally be adjusted to burn easier fuels.
This shows various fuel types, from easiest to hardest to burn. In general, the material on the left can be burnt in fire chambers designed for materials on the right.
Wood Pellets – Wood Chips – MDF and Chipboard Chips – Wood Dust – Solid Grade Laminate – Fire Retardant MDF – RDF
With customers with material on site, there is generally a dust extraction/collector system that moves all the dust into one spot on the site from all the different woodworking processes. If you have plenty of broken pallets or offcuts, you will have a chipper/grinder doing bulk reduction. The storage silo of the biomass boiler will be fed from these sources, and this can be done manually with human effort, bucket loaders or most labour efficiently with a conveying system, such as a vertical chain drag conveyor or a pneumatic cyclone transfer system.
If the material is being delivered, the fuel type and transportation method need to be considered. The delivery methods used on most trailers can be summarised as moving floor trailers and pneumatic trailers. These both have strengths and weaknesses, and it is worth looking through for your biomass boiler installation.
Moving floor trailers are good because they are the most available form of transportation and are used to carry many other bulk goods. The negatives are that the receiving equipment generally needs to be more expensive to receive the fuel as the material gets dumped on the floor behind the trailer. This can be collected via a bucket loader into a storage silo or gathered using a Toploader.
Pneumatic delivery from a truck is popular for pellets, and there are many good installation setups similar to this. However, a common issue is that the pneumatic delivery system has too many bends or is too long a distance and dry pellets can be smashed into dust. Dust isn’t a problem for Ranheat industrial biomass boilers, but it can potentially explode a pellet system with an automatic ignition system.
There are hybrid versions of these two main types, such as a walking floor that feeds into a pneumatic conveying system. Getting this right in your biomass boiler installation is the most important part of the project.
I could write a thesis on this subject. This part of the system interacts most with the outside world and varies the most from installation to installation. Find a good partner and get good advice and good equipment. The potential dangers of getting fuel delivered incorrectly expose users to the dangers of fire and explosions.
This depends on the material and the range of materials you expect. Different fuels have different bulk properties. Pellets possess the advantage of free-flowing behaviour, simplifying the process of extracting fuel from a silo, typically requiring only the presence of a hole and a minor degree of agitation.
Wood Chips and wood dust are incredibly variable. Some mixtures will flow, while some are extremely stubborn. For these materials, Ranheat manufactures conical-bottomed silos and bunker silos. The conical-bottomed silos have a rotating agitator in the bottom that brings out stubborn wood waste. The outfeeders in our bunker silos are walking floors or screws.
Conical-bottomed silos can store more products in a smaller area. On the other hand, bunker silos have lower fill height, which is important to convey into the silo.
For materials such as straw and other stringing biomass, flat-bottomed rotating screw-out feeders are required. This is because straw will bridge at any angle and must be ripped from the bulk solid.
Storage and outfeeding of biomass is another very involved subject. This is just a small range of issues. Find a good partner who knows what they are doing for your biomass boiler installation.
The main difference between biomass and burning fossil fuels is that biomass leaves ash. The amount of ash that is created varies from one fuel to another. Different tree species have different ash percentages, which measure the dry mass of fuel against the mass of ash produced.
Below is an indication of the ash percentages we have found. This can vary hugely, especially with exotic woods with large amounts of resin.
The variation is significant, and the total amount of fuel burnt has an impact, as well. Eight tons a week is enough to power a 600kW system for a week of medium duty, such as a Ranheat MSU 600. If this is solid-grade laminate, it will produce up to 1600kg of ash weekly. However, if core wood is burnt, it will produce 400kg of ash weekly.
These differences will dictate the ash conveying equipment and storage required for your project. Systems burning just core wood will have less ash. Furthermore, they will have to get to a larger scale before they can justify the extra expense of an automatic deashing conveying system. Ash conveying systems start at £12,000 and scale up from there.
Where the ash is produced is also vital. The main distinction within ash lies between bottom ash, which originates in the fire chamber, and top ash, which is captured by the flue gas filter. The sources of ash can be filled into separate bins or combined depending on the amount of ash to be removed.
Ash conveying is much like any bulk product conveying issue. The production rate will indicate what method and machinery will be the most economical. More importantly, ash conveying is something you need to get right. Otherwise, it can cause fire and explosions.
Installation of a biomass boiler poses significantly more challenges and risks than other mechanical installations. At larger scales with different materials, it becomes more of a material conveying and storage problem than a simple distributing heat issue.
This means that the biomass boiler installer you select must possess in-depth knowledge of fuel, ash management, and delivery methods essential for your specific installation while being cost-effective. Ranheat is both a manufacturer and installer of industrial biomass boilers and has 35 years of experience. In our time, we have come around many of the challenges laid out in this short guide.
We design our layouts in 3D. In tight spaces, we scan them using a 3D point cloud laser scanner, which surveys customer sites and creates a 3D version in our CAD software. This enables us to do challenging conveyor layouts in one visit without rework.
If you are considering an industrial biomass boiler, feel free to get in touch with us. We will provide you with the expert solutions you require.
MATT LOCAL
