The Feasibility of Using Microwave Induced Plasma Torrefaction for the Production of an Energy Dense, Carbon Neutral Fuel from Wood Pellets
Lead Research Organisation:
Liverpool John Moores University
Department Name: Built Environment
Abstract
There is a real need to de-carbonise energy production in the UK and elsewhere in order that Governments meet their
obligations set by the Kyoto Protocol and meet renewable energy generation targets. Using sustainable sources of wood as
a fuel is one such method of reducing the CO2 emissions associated with energy production. However, wood has a high
moisture content, low energy density, has variable combustion properties and there are considerable costs incurred
modifying existing power plants for co-firing. As result the energy sector is looking increasingly to torrefaction to produce an
energy dense and renewable "bicoal" from wood. Torrefaction is low temperature heating of wood in the absence of oxygen
to produce a char-like fuel that, once pelletised, has properties similar to coal. However, the economics of existing
torrefaction technology has yet to be proven on an industrial scale and based upon prior pilot activity we believe that
microwave induced plasma torrefation (MPT) technology provide a more cost effective way to torrefy wood. The overall
objective of our project is to develop a prototype MPT demonstration reactor for cost effectively converting wood pellets to
biocoal.
This study will bring together a unique project delivery consortium comprising of Stopford Projects Ltd (SPL) and Liverpool
John Moores University (LJMU). SPL is a multidisciplinary engineering design and project management consultancy with
significant expertise in green technology and energy projects spanning research through to plant commissioning.
This project will investigate the feasibility of using microwave plasma technology for torrefying pre-pelletised wood with the
intention of improving fuel combustion efficiencies and reducing OPEX costs. It is the intention of the consortium to
develop, test and demonstrate an industrial lab-scale reactor as an output of the project as well as developing the
technological and commercial route to market. Unlike currently available torrefaction technologies, the novel advantage of
the described microwave plasma technology is that the process has a lower parasitic load, has significantly lower capital
costs, has greater tolerance of mixed feed streams, is more durable, modular, and potentially mobile. As such the
technology presents the sector with a more efficient and cost effective method of handling and transporting woody biomass
than conventional processes.
The project will be conducted in nine Work packages:
Work package 1: Feedstock Characterisation: (2 months)
Work package 2: System specifications and boundary conditions (2 months)
Work package 3: Microwave plasma torrefaction reactor design parameters (3 months)
Work package 4: Design and build microwave plasma reactor (2.5 months)
Work package 5: Experimentation and Optimisation (3 months).
Work package 6: Process performance and analysis (2 months)
Work package 7: Engagement with endusers (2 month)
Work package 8: Regulatory Requirements (2 month)
Work package 9: Process Scale-Up and Technology Exploitation (3 months)
obligations set by the Kyoto Protocol and meet renewable energy generation targets. Using sustainable sources of wood as
a fuel is one such method of reducing the CO2 emissions associated with energy production. However, wood has a high
moisture content, low energy density, has variable combustion properties and there are considerable costs incurred
modifying existing power plants for co-firing. As result the energy sector is looking increasingly to torrefaction to produce an
energy dense and renewable "bicoal" from wood. Torrefaction is low temperature heating of wood in the absence of oxygen
to produce a char-like fuel that, once pelletised, has properties similar to coal. However, the economics of existing
torrefaction technology has yet to be proven on an industrial scale and based upon prior pilot activity we believe that
microwave induced plasma torrefation (MPT) technology provide a more cost effective way to torrefy wood. The overall
objective of our project is to develop a prototype MPT demonstration reactor for cost effectively converting wood pellets to
biocoal.
This study will bring together a unique project delivery consortium comprising of Stopford Projects Ltd (SPL) and Liverpool
John Moores University (LJMU). SPL is a multidisciplinary engineering design and project management consultancy with
significant expertise in green technology and energy projects spanning research through to plant commissioning.
This project will investigate the feasibility of using microwave plasma technology for torrefying pre-pelletised wood with the
intention of improving fuel combustion efficiencies and reducing OPEX costs. It is the intention of the consortium to
develop, test and demonstrate an industrial lab-scale reactor as an output of the project as well as developing the
technological and commercial route to market. Unlike currently available torrefaction technologies, the novel advantage of
the described microwave plasma technology is that the process has a lower parasitic load, has significantly lower capital
costs, has greater tolerance of mixed feed streams, is more durable, modular, and potentially mobile. As such the
technology presents the sector with a more efficient and cost effective method of handling and transporting woody biomass
than conventional processes.
The project will be conducted in nine Work packages:
Work package 1: Feedstock Characterisation: (2 months)
Work package 2: System specifications and boundary conditions (2 months)
Work package 3: Microwave plasma torrefaction reactor design parameters (3 months)
Work package 4: Design and build microwave plasma reactor (2.5 months)
Work package 5: Experimentation and Optimisation (3 months).
Work package 6: Process performance and analysis (2 months)
Work package 7: Engagement with endusers (2 month)
Work package 8: Regulatory Requirements (2 month)
Work package 9: Process Scale-Up and Technology Exploitation (3 months)
Planned Impact
This project will see the development of a novel microwave plasma torrefaction (MPT) technology; which operates at a fraction of the cost of existing technologies, and will lower GHG emissions associated with energy generation by making available a low cost, energy dense, carbon neutral feedstock. Our proposal aligns with the competition brief as microwave plasma torrefaction is "innovative" and "can deliver a step change in the cost of performance of low cost sources of
energy". The technology will also integrate future demand and energy supply into a flexible, secure and resilient energy system; reducing GHG emissions at point of use.
Wood is bulky and contains 40% to 50% moisture, has a low CV, a low energy density, and is heterogeneous; resulting in a wide variety of combustion problems and high CO2 emissions per unit of energy transported. Some of these issues are addressed by pelletising. However, pelletised wood still contains a significant fraction of moisture (~10%), is prone to biodegradation and can auto combust. Wood pellets also absorb moisture during storage and incur high handling and storage costs. Large scale combustion of wood pellets is also prone to slagging and fouling of the incineration chamber. To address these issues the wood fuel industry is showing considerable interest in torrefaction. During torrefaction, the properties of wood are altered to provide a better quality fuel that is hydrophobic and biologically inert, and once it is briquetted or pelleted it produces a very energy-dense fuel with properties similar to coal (often referred to as biocoal). However, the economics of biocoal production using standard technologies are unproven. In contrast, microwave plasma
torrefaction can be used to produce biocoal, but due to its low CAPEX, OPEX, small plant footprint and superior operational efficiencies, MPT has significant potential to bring to the market a low cost, carbon neutral fuel that can be readily employed to de-carbonise energy generation. For a potentially paradigm shifting technology with such a large market, our research budget is modest, and the consortium believes that by focusing resources towards a sector that is looking for novel solutions (and one in which the consortium operates), MPT can be developed and proven for relatively little outlay, representing an excellent risk to reward ratio. We envisage several spin-out applications for MPT including an energy rich feedstock for use in biochemical synthesis (via the Fischer Tropsch process). The market for biocoal is clearly definable and includes power generators at all scales, making MPT an extremely attractive proposition to technology investors.
The OECD has estimated that Europe uses 405 million tonnes coal per annum. Therefore the potential market for bio-coal is vast, as biocoal can be used to offset coal consumption. Although the complete replacement of coal with biomass is not feasible, assuming that 10% of the electricity from coal combustion will be replaced by co-firing biomass, and that 10% of the replaced biomass is biocoal, a 4 million tonne market for our product can be envisaged. Initial calculations suggest that
the profit in biocoal (after production and transportation) is circa £50 per tonne, yielding a potential market value of £200 million as a fuel for co-firing. It can be seen that the business that develops a way to economically produce biocoal at the required tonnage will capitalise on an extremely lucrative market, even at the conservative values quoted here. It is our intention to develop, globally market and licence our microwave plasma torrefaction technology for this purpose. Hence Manufacture/deployment of MPT will present economic benefits across the supply chain with social benefits include; job protection, job creation, and a reduced reliance on fossil fuels. We anticipate that microwave plasma torrefaction will create employment at a time of restrictions on investment and recruitment.
energy". The technology will also integrate future demand and energy supply into a flexible, secure and resilient energy system; reducing GHG emissions at point of use.
Wood is bulky and contains 40% to 50% moisture, has a low CV, a low energy density, and is heterogeneous; resulting in a wide variety of combustion problems and high CO2 emissions per unit of energy transported. Some of these issues are addressed by pelletising. However, pelletised wood still contains a significant fraction of moisture (~10%), is prone to biodegradation and can auto combust. Wood pellets also absorb moisture during storage and incur high handling and storage costs. Large scale combustion of wood pellets is also prone to slagging and fouling of the incineration chamber. To address these issues the wood fuel industry is showing considerable interest in torrefaction. During torrefaction, the properties of wood are altered to provide a better quality fuel that is hydrophobic and biologically inert, and once it is briquetted or pelleted it produces a very energy-dense fuel with properties similar to coal (often referred to as biocoal). However, the economics of biocoal production using standard technologies are unproven. In contrast, microwave plasma
torrefaction can be used to produce biocoal, but due to its low CAPEX, OPEX, small plant footprint and superior operational efficiencies, MPT has significant potential to bring to the market a low cost, carbon neutral fuel that can be readily employed to de-carbonise energy generation. For a potentially paradigm shifting technology with such a large market, our research budget is modest, and the consortium believes that by focusing resources towards a sector that is looking for novel solutions (and one in which the consortium operates), MPT can be developed and proven for relatively little outlay, representing an excellent risk to reward ratio. We envisage several spin-out applications for MPT including an energy rich feedstock for use in biochemical synthesis (via the Fischer Tropsch process). The market for biocoal is clearly definable and includes power generators at all scales, making MPT an extremely attractive proposition to technology investors.
The OECD has estimated that Europe uses 405 million tonnes coal per annum. Therefore the potential market for bio-coal is vast, as biocoal can be used to offset coal consumption. Although the complete replacement of coal with biomass is not feasible, assuming that 10% of the electricity from coal combustion will be replaced by co-firing biomass, and that 10% of the replaced biomass is biocoal, a 4 million tonne market for our product can be envisaged. Initial calculations suggest that
the profit in biocoal (after production and transportation) is circa £50 per tonne, yielding a potential market value of £200 million as a fuel for co-firing. It can be seen that the business that develops a way to economically produce biocoal at the required tonnage will capitalise on an extremely lucrative market, even at the conservative values quoted here. It is our intention to develop, globally market and licence our microwave plasma torrefaction technology for this purpose. Hence Manufacture/deployment of MPT will present economic benefits across the supply chain with social benefits include; job protection, job creation, and a reduced reliance on fossil fuels. We anticipate that microwave plasma torrefaction will create employment at a time of restrictions on investment and recruitment.