Biomass Pelleting
Background to Biomass
The raw material used for making fuel pellets is called biomass. Biomass is any living or recently dead material that can be used as fuel. This includes any wood and waste wood products.
Biomass includes:
- Wood round logs, chips and sawdust
- Bagasse
- Agricultural residues
Renewable fuel has exponentially increased its market share in the global energy mix from 6% in 2008 to 19% in 2015, and biomass (primarily in the form of wood pellets manufactured from wood waste) represents 50% of all renewable fuel used worldwide. Biomass is the only renewable resource that can produce and supply power on a sustainable 24/7 bases.
Various forms of alternative energy are currently being utilised worldwide, however none are truly 24/7, except for biomass wood pellets which have proved over the last 30 years to be the leading alternative energy worldwide. The global production of wood pellets has shown an exponential growth: from 2 million tonnes being produced in 2000 to 19.5 million tonnes in 2012, to 32 million tonnes in 2017.
It is predicted that by 2020 the annual demand will reach more than 59 million tonnes.
Introduction to Wood Pellets
Wood pellets are made from clean, compressed sawdust and wood waste. They are increasingly being used by the energy industry in purpose-built or converted coal-burning power plants, notably in Europe, UK, Japan and Korea, where the energy sector is striving to meet renewable targets and climate change goals. Air quality considerations are helping to make wood pellets an increasingly popular alternative to burning coal for electricity generation.
Wood pellets are manufactured by reducing all types of round wood and wood waste to a uniformed particle size, drying the raw material to a low moisture content and then extruding the wood particles to form a wood pellet.
Wood Pellet Production Cycle
ONE
Locally harvested and sustainable forestry practices
TWO
Fiber is transported to the pellet plant and then locally manufactured
THREE
Production process is continuosly monitored for quality and product control
FOUR
Screening and cooling process assures quality and plant cleanliness
FIVE
The pellets are bagged or prepared fir bulk shipping
SIX
Local and international bulk delivery
SEVEN
Product is shipping to customer location by rail, barge or truck
EIGHT
Immediate and continued savings are passed down to our customers
Wood pellets used as fuel are usually 6 to 8 mm in diameter and have a maximum length of 30 mm. There are three types of wood pellets manufactured for the renewable energy sector (see below). White Pellets are the traditional type of pellets which are currently manufactured and used globally. The Black Pellet is a new revolutionary pellet which has taken more than ten years to develop to an operational level.
Wood Pellet types
There are three types of wood pellets manufactured for the renewable energy sector:
Industrial grade White
Pellets (A1)
These are used as fuel by power utilities for electricity power production and Combined Heat and Power (CHP) for industrial and commercial use (space heating, boiling water and industrial steam). Combined Heat and Power is the cheapest form of direct thermal energy to produce heat, hot water and steam in comparison to any other form of energy.
Black Pellets
These are used as fuel for domestic and commercial thermal heating systems that produce hot water, space heating and cooling, and steam for domestic and commercial / industrial applications.
Premium grade White
Pellets (EN Plus)
These can be used for all application types.
Wood Pellet Market
The pellet market can be divided into three sectors:
Power Plants and Power Utilities
Power Plants are predominately fuelled with fossil fuels and are constantly under pressure to reduce their greenhouse gasses. When the wood pellet industry was in its infancy, many power plants replaced 10 -15% of coal in their boilers with wood pellets as a co-generation application. This in turn reduced their greenhouse gas emissions, lowered their ash content, and lowered their boiler and conveyor maintenance costs.
In the last five years major power plants in the UK and Europe have converted 50% of their boilers to only use wood pellets, which has resulted in significantly reducing the cost of carbon taxation, maintenance and ash disposal.
Commercial and Industrial Combined Heat and Power Strategies
Commercial and industrial entities use electricity to heat space and water, and to create steam and cooling. Instead of using electricity, wood pellets can be used in a thermal capacity to perform these applications.
The use of pellets in a thermal capacity results in achieving an 87% efficiency, compared to a 35% fuel efficiency when electricity is used for the same heating function. Thus the use of pellets significantly reduces the cost of heating and cooling for commercial and industrial entities.
This thermal process has been common practice throughout the United States, Europe and Asia for the last two decades. Combined Heat and Power is commonly used in the following sectors:
| SECTOR | FUEL |
|---|---|
| Farming applications | Heat – cooling |
| Hospitals & clinics | Heat – cooling – hot water - steam |
| Hospitality – hotels, game lodges & BnB | Heat – cooling – hot water - steam |
| Mining applications | Heat – cooling – hot water |
| Forestry nurseries | Heat – hot water |
| Freezer store | Cooling |
| Gymnasiums | Heat – cooling – hot water - steam |
| Shopping centres | Heat – cooling – hot water |
| All drying applications | Heat - hot water - steam |
| Office blocks | Heat – cooling – hot water |
| Wine industry | Cooling – hot water - steam |
| Housing estates | Heat – cooling – hot water |
| Automotive | Heat – hot water - steam |
Domestic Applications
Biomass Associations in Europe expect that the consumption of high-quality wood pellets for heating purposes will increase from over 7 million tonnes in 2011 to 22 million tonnes in 2020. The growth of this market is driven by the competitiveness of wood pellets compared to conventional fossil fuels, such as natural gas and oil.
Typically for the domestic market is that approximately 80% of pellet production is EN Plus certified. The EN Plus certification system sets high requirements on pellet quality and sustainability.
They can also be used for
- Water purification
- Fixed carbon additive applications
- As a fertilizer additive
- As a carbon steel production additive
- Wood pellets can be fed into a burner by auger feeding or buy pneumatic conveying. They can be conveniently blown from a tanker to a storage bunker.
Black Pellets
The black pellet production process adds an additional step to the traditional white pellet production procedure – the ‘thermal island’ process. The ‘thermal island’ process involves the application of pressure, heat and steam to the biomass, and takes place in one piece of stainless steel equipment. The ‘thermal island’ process melts the lignin inside the biomass and when it passes through the pellet mill the lignin acts as a natural adhesive and waterproofing agent. This process gives the black pellet its ‘unique qualities’.
In addition to black pellets being highly suitable for these fuel applications:
There are many benefits associated with the utilization of wood pellets. Benefits include:
- Reduced greenhouse gas emissions and thus enables plants to comply with clean air regulations.
- Helps stabilize the combustion of coal in boilers.
- Enables smooth automatic feeding with very fine calibration, due to their geometry and size.
-
Wood pellets can be fed into a burner by auger feeding or by pneumatic conveying. They can be conveniently blown from a tanker to a storage bunker.
They can also be used for
- Water purification
- Fixed carbon additive applications
- As a fertilizer additive
- As a carbon steel production additive
There are many advantages with using black pellets compared to the use of coal and white pellets.
Black pellets:
- Have a higher calorific value (19.5 MJ/kg – like steam coal) compared to coal and white pellets.
- Have a higher bulk density (750 kg/m3) compared to coal and to white pellets. The higher density also permits compact storage and rational transport over long distances in comparison to the other fuel types.
- Have fewer particulate fines (1%) compared to coal and white pellets.
- Have lower ash content (0.5%), thus there is less ash which requires disposal (1% compared to 38% from coal), and emissions compared to coal and white pellets. This also results in significantly reduced operational costs.
- Can be transported and stored in the open, whereas white pellets must not be exposed to the elements.
- Utilities that currently use coal, can directly substitute black pellets for coal without the need to implement costly technical adjustments to their boilers and feed systems. Black pellets can be incorporated into existing coal piles, reclaimers, Can be stored on the ground, left exposed to rain, snow and humidity, can be pulverized the same way as coal in coal crushers, and does not have the transportation issues which are associated with white pellets; as it can be transported in open trucks, rail cars, and barges — just like coal. Thus, there are no costly capital investments required when making the transition to black pellets.
