Biomass boiler systems can’t be ignored when it comes to heating efficiency with reduced emissions and low carbon footprints. These units have gained quite some popularity among small businesses and residential communities for their ability to produce low waste and manage carbon dioxide in the atmosphere.
These boilers come in different sizes, shapes, installation technologies, and fuel types, which makes it challenging to find the right match. To help you choose one, here is an in-depth guide on biomass boiler systems based on their working principle, efficiency, emissions, and cost.
How Does Biomass Boiler System Work?
How does a biomass boiler work？ A number of steps are involved.
1st Phase
Biomass boiler system works like traditional boilers and generates heat by combusting non-fossil fuels. These are bigger than other counterparts, because the fuel used in the chambers is in large volume, which takes up space.
2nd Phase
The fuel used to run a typical biomass boiler system includes wood pellets, wood chips, and logs. This fuel is fed into the combustion chamber to start the process. The feeder can be automatic, semi-automatic, and manual, based on the working facility and budget.
3rd Phase
Once the fuel is ignited within these chambers, it generates hot gases. These hot gases pass through the flue and into the heat exchanger chamber. During this process, the hot air in the chambers heats the water. Next, the water converts to steam and is transferred to the industrial equipment.
4th Phase
Finally, the by-product ashes are discarded into a separate tray, and the left-over heat goes into the thermal storage containers. These containers are also known as thermal tanks or buffer vessels. to make the process convenient, it is advised to always have the bulk of fuel present in your facility. This reduces the cost of frequently traveling the heavy wood logs and pellets.
Biomass boiler system is an ideal choice for homeowners looking for a more sustainable and efficient heating system. These boilers take advantage of natural sources such as wood pellets, chips, logs, and other organic materials to generate heat.
Using biomass systems for homes is a great way to reduce your carbon footprint as a homeowner. Unlike traditional oil and gas boilers, biomass boilers don’t rely on fossil fuels and are instead powered by renewable sources. As a result, they are much more environmentally friendly, since they emit fewer pollutants.
It is an excellent choice for homeowners looking for a more efficient, sustainable, and low-maintenance heating system. With their low emissions and high efficiency, biomass boilers are an ideal way to reduce your carbon footprint while still providing reliable heat to your home.
Combustion Process of a Commercial Biomass Boiler System
Biomass steam boilers for commercial areas are a great means to reduce the carbon footprint, decrease the electricity cost, and produce clean heat energy. They are currently used in public as well as private industrial sites. It is estimated that the largest 500 MWth boiler plant in a big facility can increase the heating efficiency by up to 89%.
The Combustion Process
The combustion process remains the same, as it is built on the four primary units, including the feeding system, combustion chamber, air supply, and ash discharge. In industrial setups, this is further accompanied by a gas recirculation FGR, an automatic controller, and a separate heat exchanger.
However, the installation techniques used for each facility determine the efficiency and what type of fuel to use. For instance, most facilities use moving-grates furnaces that can utilize all sorts of homogenous fuel. In contrast, the ones with rotating and circulating beds are limited to woodchips, bark, and sludge.
| Installation Technology | Fuel Type |
| Moving-Grate Systems | All Fuels (Homogenized) |
| CFB (Circulating Fluized Bed) | Small Materials (bark, woodchips, and sludge) |
| PF (Pulverized Wood Boilers) | Small and Dry (pellets, sawdust, and wood) |
| Pulverized Coal-Wood Burners | Small and Dry (pellets and sawdust) |
Factors that Determine the Efficiency of a Woodchip Boiler
The efficiency of a biomass boiler depends on a number of factors, including the quality of fuel, the type of fuel, emission value, and the temperature regularities within the system. Here are 3 critical factors that can influence the heating efficiency of your installed commercial boiler.
1. Flue Gas Temperature
Flue gases can be defined as gases that leave the chamber during combustion. These gases are responsible for producing heat and keeping the water hot. To determine the efficiency, the difference between the initial temperature and the flue temperature is taken. In case the gases are still hot when leaving the chamber, it means that the flue gases have not transferred their heat to water. So, the heat gets lost in the process. Hence, it is ideal for industries to have separate maintenance setups installed to prevent any heat loss.
2. Type of Biomass Fuel
On average, a typical biomass boiler system has around 80-90% efficiency as compared to other conventional heating setups. However, a large part of it comes down to what type of fuel you are using for residential and industrial sites. Here is a breakdown of the most commonly used fuels, their moisture level, and energy efficiency.
| Type of Fuel | Energy per Ton (Moisture Content) |
| Wood Chips | Around 4800 kWh (10-15%) |
| Wood Logs | Around 3500 kWh (25-30%) |
| Wood Pellets | Around 4800 kWh (5-8%) |
| Saw Dust | Around 1500 kWh (less than 20%) |
3. Emission Level
In simple words, it wouldn’t be wrong to say that low emissions mean better heating efficiency. The emissions produced by commercial biomass boiler systems can be divided into CO2, NOx, and PM. And it is determined by what quality fuel you are using.
Overall, the Carbon footprint and Nitrogen emission are negligible in a biomass boiler, which is directly proportional to the energy efficiency of the system. However, the probability of high PM emissions is one of the biggest concerns in this regard, specifically in urban industrial setups.
CO2
This is a common fact that the carbon dioxide produced by burning any wood material is high, given that it has a high calorific value. However, studies show that the CO2 emit from burning biomass is already a part of the natural atmospheric carbon cycle. Hence, you will see companies claiming that biomass boiler fuel is carbon neutral or that biomass fuel has a low carbon footprint.
NOx
When it comes to NOx emission, a large part of it is determined by the quality of fuel you are using. For instance, small dry pellets are known to have low emissions that tend to lie between 50 and 60 mg/MJ. In contrast, the chip boilers will emit around 170 or 180 mg/ MJ. in either case, the emissions are negligible, which keeps the efficiency intact in a biomass boiler system.
PM Particulate Emissions
Biomass fuel tends to have more particulate emissions than natural gas. When compared to fuel oil, there isn’t much difference. A typical modern industrial biomass boiler system can produce emissions between 10 and 70 mg/ MJ, which is quite similar to the value produced by oil.
However, using low-quality wood and incorrect equipment can increase this value in the commercial setting. And when they are positioned in urban areas, the air quality is compromised. To prevent this, most facilities use ceramic filters to keep these emissions low and improve the efficiency of the boiler.
4. Thermal Storage Capacity
Thermal storage is another critical element of any conventional or biomass steam boiler system. In simple words, it can be defined as the space that allows boilers to store heat energy, which can ultimately extend the working life of the boiler. High thermal storage means better heating efficiency and low emissions. Each boiler unit comes with buffer tanks that act as a battery to store this energy.
A study conducted by the ACS publication showed that having large thermal storage can reduce the cycling rates and the emissions. It was stated that the efficiency of a 25 KW modern biomass boiler was increased up to 74% with a buffer tank, as compared to 57% without one. However, the problem with biomass boiler systems is that having a separate buffer container can add to the already big size.
Cost of a Biomass Boiler
Here is a breakdown of what you should expect when it comes to the cost of a basic residential and commercial biomass boiler system.
Installation Cost
It is noted that buying and installing a biomass boiler can be expensive, specifically for residential sites. Here, the price difference is determined by its size and whether it has an automatic or manual feeder. A 15kW boiler works for both residential spaces and small businesses. If you look for an automatic one, it can cost you around $16000 – $18000, while a manual one would cost you around $11000 – $13000.
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Boiler Running Fuel Cost
The boiler fuel cost of a biomass boiler would be better or similar to the conventional counterparts, based on the fuel type. Most industries use wood pellets which can cost around $200 to 300 per ton. So, when we use this cost of biomass boilers for homes, the approximate value would be around $3000 per year.
Maintenance
The maintenance cost of a biomass boiler system is negligible. This is because they only produce ashes as a by-product. Here are some things that residential as well as commercial owners can do to extend the life of the boiler and improve its efficiency.
- Remove ashes every week or invest in a self-cleaning biomass boiler
- Maintenance of the feeding system (basic repairs after every two months are ideal)
- Clean the heat exchanger and ash discharger every week
- Log boilers tend to be a bit pricey, given that they produce more ashes and demand daily cleaning
- Annual technician checkups to make sure the boiler is working fine
How can I get a biomass boiler grant?
If you are interested in obtaining a biomass boiler grant, make sure you maximize your chances by following these steps.
First, research the various grants available for biomass boilers and identify the one that best fits your needs. Make sure you check the eligibility criteria for the grant and ensure you meet all the requirements.
Next, you should contact the relevant bodies responsible for offering the grant. This could include local councils, energy companies, or government departments. Your grant advisor should be able to provide you with detailed information about the grant and the application process.
Once you have obtained the information you need, you should complete the application form. Make sure to include all the required information and any supporting documents. If you have any questions or need help with the process, the relevant authority should be able to help.
Finally, you should submit your application.
Following this, you should receive a response within a few weeks. If your application is successful, you will receive the grant and be able to use it to purchase a biomass boiler.
You can successfully apply for a biomass boiler grant if you follow these steps. Good luck!
Conclusion
Biomass boilers are known for their minimal waste production and low carbon footprint. This is the reason why most businesses and industrial setups are turning towards it. However, choosing one specific to your requirements can be a challenge. So, before you choose any biomass boiler system for your firm, make sure to consider everything from the maintenance cost to installation space, efficiency, and design.