Final Report Summary - PLAGASMIC (Advanced Microwave Plasma Gasification of pig and cow manure for cost-effective biogas generation.)
Executive Summary:
European SMEs operating in livestock farming (>2.21million) are under increasing pressure from supermarket purchasing powers, legislation, biofuel crops (as they compete with the livestock farmers for land) and environmental issues, which has resulted in substantially reduced profits for the community. In 2010, the average income for a farmer dropped by 27% compared to its value in 2003.
The Common Agricultural Policy (CAP) in the EU unevenly distributes subsidies to large farms and land owners while small- and medium-sized farms struggle to survive on less than minimum wage.
For example, in Spain, the top 18% of big farms received 76% of all subsidies and 37,000 family-run farms disappear each year. In addition, the livestock sector is faced with increasing legislation that, in time, will ban current methods for disposal of manure. Currently >90% of the 1,578 million tonnes of cow and pig manure produced per year are disposed of by being spread on fields as fertiliser. As manure contains high amounts of nitrogen and phosphorus, its disposal by this spreading method has become a problem.
Application of excessive amounts of manure to land can lead to surface and ground water
contamination through the accumulation of minerals in the soil. Nitrate and phosphate levels in many European waters are increasing to dangerous levels with over 70% of nitrate entering water from over-fertilisation of agricultural land. As a result, farmers in the EU are confronted with an increasing number of essential regulations and administration that limits the degree of freedom in farming, especially in intensive animal production. For example, the Nitrates Action Directive places a severe restriction on the quantity of organic manure that can be applied to land (170 kg N/ha/year) in addition to regulations forbidding land application during 4 months of the year and minimum storage periods of 6 months. In addition, the level of spreadlands currently available is inadequate for the amount of manure produced and would need to drastically increase in order to meet the limits set by the Nitrates Directive.
In order to meet vital legislation, livestock farmers may have to export the manure off the farm to landfill; this practice will expose the farming community to substantial increases in cost (>70% increase on current cost), due to landfill tax and transport costs. In addition export of manure off the farm is not always a viable alternative as transport of raw manure further than 15km is uneconomical due to its high water content (>70% by weight).
In order to meet on-farm nitrate and phosphate balance, the livestock sector has already been using low-protein animal feed, and low emissions techniques for the storage, handling and application of animal manure. These methods now used by farmers are proving expensive for the farming community and relatively inefficient. In addition improved farming practices alone will not be sufficient to meet the demanding environmental objectives for phosphates in surface waters as part of the European Nitrate Directive and Water Framework Directive, in which livestock manure loadings are limited to an overall farm limit of 170kg/ha total nitrogen on arable land; this is equivalent to limits for phosphorus of 19 kg/ha and 43 kg/ha respectively for cattle and pig manure.
Alternative methods for disposal of manure such as anaerobic digestion or gasification can be used for the conversion of manure into syngas or biogas for production of energy or use as a biofuel.
However these technologies require a minimum guaranteed tonnage to cover their high operating and capital cost. Therefore their operation involves transport of manure feedstocks from various farms to the operating site, increasing the risk of animal disease transmission between farms through cross-contamination from vehicle movements between farms and the centralised site.
Concern for the economic burden that implementation of existing and future legislation on nitrate and phosphate balances would place on the livestock farming community has driven Ashleigh Farms pig farmer with over 1500 sows that produce approximately 37000 pigs per year with further 10 fold of their counterpart Irish Farmers Associations to find an economical solution for the disposal of manure that would allow the livestock farming community to comply with important legislation while competing with cheap meat imports from the USA.
Our project, PlaGasMic has responded to an urgent need from the livestock farming community todevelop an environmentally-friendly method for disposal of animal manure such that the economic, competitive and legislative burdens on them may be eased. PlaGasMic involves the pyrolysis of manure using microwave induced plasma (MIP) technology allowing a rapid release of gases rich in hydrogen (‘syngas’). In addition we will collect a water-based liquid that will be subjected to electro-coagulation and filtration processes to obtain clean water suitable for farm cleaning, and additional salts with potential use as fertilisers.
Project Context and Objectives:
The Project concept
European SMEs operating in livestock farming (>2.21million) are under increasing pressure from supermarket purchasing powers, legislation, biofuel crops (as they compete with the livestock farmers for land) and environmental issues, which has resulted in substantially reduced profits for the community. In 2010, the average income for a farmer dropped by 27% compared to its value in 2003.
The Common Agricultural Policy (CAP) in the EU unevenly distributes subsidies to large farms and land owners while small- and medium-sized farms struggle to survive on less than minimum wage. For example, in Spain, the top 18% of big farms received 76% of all subsidies and 37,000 family-run farms disappear each year. In addition, the livestock sector is faced with increasing legislation that, in time, will ban current methods for disposal of manure. Currently >90% of the 1,578 million tonnes of cow and pig manure produced per year are disposed of by being spread on fields as fertiliser. As manure contains high amounts of nitrogen and phosphorus, its disposal by this spreading method has become a problem.
Application of excessive amounts of manure to land can lead to surface and ground water contamination through the accumulation of minerals in the soil. Nitrate and phosphate levels in many European waters are increasing to dangerous levels with over 70% of nitrate entering water from over-fertilisation of agricultural land. As a result, farmers in the EU are confronted with an increasing number of essential regulations and administration that limits the degree of freedom in farming, especially in intensive animal production. For example, the Nitrates Action Directive places a severe restriction on the quantity of organic manure that can be applied to land (170 kg N/ha/year) in addition to regulations forbidding land application during 4 months of the year and minimum storage periods of 6 months. In addition, the level of spreadlands currently available is inadequate for the amount of manure produced and would need to drastically increase in order to meet the limits set by the Nitrates Directive.
In order to meet vital legislation, livestock farmers may have to export the manure off the farm to landfill; this practice will expose the farming community to substantial increases in cost (>70% increase on current cost), due to landfill tax and transport costs. In addition export of manure off the farm is not always a viable alternative as transport of raw manure further than 15km is uneconomical due to its high water content (>70% by weight).
In order to meet on-farm nitrate and phosphate balance, the livestock sector has already been using low-protein animal feed and low emissions techniques for the storage, handling and application of animal manure. These methods now used by farmers are proving expensive for the farming community and relatively inefficient. In addition improved farming practices alone will not be sufficient to meet the demanding environmental objectives for phosphates in surface waters as part of the European Nitrate Directive and Water Framework Directive, in which livestock manure loadings are limited to an overall farm limit of 170kg/ha total nitrogen on arable land; this is equivalent to limits for phosphorus of 19 kg/ha and 43 kg/ha respectively for cattle and pig manure.
Alternative methods for disposal of manure such as anaerobic digestion or gasification can be used for the conversion of manure into syngas or biogas for production of energy or use as a biofuel. However these technologies require a minimum guaranteed tonnage to cover their high operating and capital cost. Therefore their operation involves transport of manure feed stocks from various farms to the operating site, increasing the risk of animal disease transmission between farms through cross-contamination from vehicle movements between farms and the centralised site.
Concern for the economic burden that implementation of existing and future legislation on nitrate and phosphate balances would place on the livestock farming community has driven Ashleigh Farms pig farmer with over 1500 sows that produce approximately 37000 pigs per year with further 10 fold of their counterpart Irish Farmers Associations to find an economical solution for the disposal of manure that would allow the livestock farming community to comply with important legislation while competing with cheap meat imports from the USA.
Our project, PlaGasMic will respond to an urgent need from the livestock farming community to develop an environmentally-friendly method for disposal of animal manure such that the economic, competitive and legislative burdens on them may be eased. PlaGasMic involves the pyrolysis of manure using microwave induced plasma (MIP) technology allowing a rapid release of gases rich in hydrogen (‘syngas’). In addition we will collect a water-based liquid that will be subjected to electro-coagulation and filtration processes to obtain clean water suitable for farm cleaning, and additional salts with potential use as fertilisers.
The main features of our technology are:
• A microwave plasma reactor that used to process animal manure. The reactor has two outputs – waste water containing nitrate and phosphate salts, and a hydrogen-rich gaseous mixture (syngas). The application of microwave induced plasma to animal manure for the production of syngas is novel and the best parameters will need to be experimentally determined.
• The use of microwaves as a pre-treatment methods to breakdown the contents of waste into rich liquid ideal “super soup” for speeding up the digestion process.
• The reactor consists of multiple microwave (MW) sources operating over a range of frequencies (2.45 GHz to 10 GHz) and power ratings. However, for industrial costing purposes and off shelf sources, it was recommended by the industrial p[partners to use sources operating at 2.45GHz.
• An electro-coagulation filtration system applied to the effluent in order to recover 0.7 to 0.9 litres of water per litre of manure with purity >99%. This process has allowed us to separate the nitrate and phosphate salts such that they may be used as fertilisers thereafter.
The main composition of this syngas will be 0.5% H2 and 7% CO for pig manure and 3% H2 and 42% CO for cow manure. This syngas has a calorific value of 142,000 J/g H2 and 10,107 J/g CO respectively and could be used directly in a gas-fired boiler unit (using the syngas produced as fuel) in order to heat water that could provide heat for the farm, or used directly in an engine for production of electricity which will be sold to the electricity grid.
In addition to the syngas this technology will generate 0.7 to 0.95 litres of effluent per litre of manure (depending on the moisture content of the manure). This effluent will be subjected to electro-coagulation and filtration systems producing water of 99% purity for farm cleaning in addition to nitrate and phosphate salts that could be used as fertilisers.
Scientific and technological objectives
Microwave heating can offer increased flexibility and control over traditional methods of heating, resulting from the instantaneous transfer or “coupling” of energy to molecules and ions. This results in systems that have greatly reduced thermal lag and consequently rapid heating and cooling rates can be achieved which can in part account for improvements in rate, yield and product selectivity.
Microwaves, electrical and magnetic field energies, are able to heat materials by two actions, namely dipole rotation and ionic conduction and both are able to absorb microwave energy by oscillating in the microwave field. Dipole materials have large dielectric constants and dielectric losses. Currently, the microwave source most commonly used is the fixed frequency 2.45GHz magnetron like the current house hold microwave ovens.
Although the use of 2.45GHz microwaves are reported to enhance the rate of chemical reactions or to produce a different product profile which can lead to higher yields, 2.45GHz is not necessarily the optimum frequency to use. For example, the Figure below shows the microwave dielectric loss for water, which represents power absorbed as a function of wavelength and temperature. For 2.45GHz the wavelength is 12.2cm and 11 as it dramatically decrease as the temperature increases. Hence the optimum operating frequency is not 2.45GHz but 10GHz (wavelength= 3cm) at room temperature but increases to 100GHz (wavelength= 3mm) at 100oC. Hence one of the focuses in this proposal is to deal with the Pigs/Cow waste physical properties of which the tuneable microwave source can maximise the microwave energy absorption.
Microwave Plasma, uses much focused energy with electrical field is about 10 fold higher in comparison with field generated by a conventional microwaves. Plasma gasification is a partial thermal degradation of a substance under sub-stoichiometric conditions (i.e. in the presence of oxygen but with insufficient oxygen to oxidise the fuel completely). The process uses high electrical field and high temperatures >4000 degree C to break down waste into its basic elemental composition, under controlled oxygen conditions, producing a synthesis gas and an inert vitrified slag.
Electro-coagulation is already used around the world to treat wastewater from mining, pulp and paper and metal processing industries and is highly effective in the removal of suspended and dissolved materials from solution; for example, phosphate levels in solution can be reduced by greater than 50% in one pass through the unit. However, the system has not been applied to the treatment of wastewater from a microwave plasma system and therefore will need further development.
The primary goal of the PlaGasMic project is to design, build and demonstrate a microwave plasma reactor integrated with electro-coagulation technology for continuous conversion of different types of manure into syngas for use as a fuel. In addition to the syngas, this technology managed to generate 0.7 to 0.9 litres of effluent per litre of manure (depending on the moisture content of the manure). This effluent was subjected to electro-coagulation and filtration to produce clean water for use in the farm in addition to nitrate and phosphate salts that could be used as fertilisers.
Scientific Objectives:
WP1: To investigate and characterise the effects of temperature (600 to 1000°C), time of reaction (hours to <2 days), range of operating frequency (2.45 to 10 GHz) and power applied to manure with moisture content. To research self-tuning of microwave sources to operate at various frequencies ranging from 2.45 to 10 GHz and automatic modulation of power levels to maintain optimisation.
WP2: To determine the range of current density to apply in the electro-coagulation process to the wastewater produced from the microwave process in order to achieve water with <0.2% suspended solids.
Technical Objectives:
WP1: To measure the dielectric properties of manure with water content between 70 and 95% across a range of frequencies (2.45 GHz to 10 GHz).
WP3: Design and build a microwave plasma reactor in which a single cavity will be used for all frequencies in the range of 2.45 to 10 GHz allowing multimode resonance conditions to be maintained at all times. In this system coupling waveguides will be used to allow any microwave source (i.e. magnetrons and travelling waves tubes) to be attached over the cavity.
WP4: Design and build an automated microwave plasma monitoring system in which software analysis will identify the salient parameters for each sensor (based on temporal analysis, spectrum analysis and response times) which will be used to map the parameters against the moisture content in the manure.
WP5: Design and build an electro-coagulation filtration system capable of treating up to 8 litres of processed effluent per minute. This system designed to recover 0.7 to 0.9 litres of water (<1% suspended solid) per litre of manure process.
WP1-6: Design, build and demonstrate a microwave plasma reactor for continuous processing (capacity of 3000 litres a day) and with an energy consumption of <7 kW per day, capable of producing up to 5 to 30 g of H2 per litre of manure processed.
Integrated Objectives:
WP7: Validation of performance of the prototype model at test sites through
• Verification of yield of syngas and clean water from different types of manure.
• Verification of time of reaction in relation to yield of syngas and water recovery.
• Verification of temperature of reaction in relation to yield of syngas and water recovery.
• Verification of energy consumption in relation to yield of syngas and water recovery.
Economic Objectives:
WP1-9: The final system has tested with expectation of a life expectancy of 10 years and can be priced at €100,000 (capital cost) compared to centralised facilities that cost over €4.5 million. We estimate that with a throughput of 750,000 litres per year (1000 units of live stock) and operating costs of <10% the capital cost per year (approx. €2200) with a quick payback period will be achieved. This is more than 25 times cheaper than a traditional anaerobic digestion system. The main capital cost is related to the microwave source and its operating power.
Although the payback of our technology is very attractive the main objective of PlaGasMic project is to provide a solution for disposal of manure to all sizes of livestock farms.
In order to achieve a solution within reach of small sized farms our technology will be modular. The number of reactors in use will be dependable on the size of the livestock farm. One reactor will be capable of treating up to 300,000 litres of manure per year (suitable for a farm with less than 500 heads of livestock). The effluent generated by the microwave plasma reactors will be fed into one electro-coagulation unit and an additional plasma source in order to recover the nitrogen and phosphorus salts and produce water for farm cleaning use.
During the project, the industrial partner’s option was to design a mobile compact system that meeting the needs for the farmers with multi components modules. In addition as the PlaGasMic system has a small footprint with a scale out potential to suit the industrial need. This can be in the form of using only one microwave source with high power of 30kW or multiple ones of 1kW unit similar to that of house hold microwave oven. Thus making our technology to have a massive potential over the current technologies which could be mobile between farms. Groups of small farmers will be able to buy a system between them and move the unit from one farm to another when it is needed. In addition we will consider the possibility of renting the technology to farmers with less than 1000 units of livestock.
Project Results:
Please see the attached summary report.
Potential Impact:
Please see the attached the impact report.
European SMEs operating in livestock farming (>2.21million) are under increasing pressure from supermarket purchasing powers, legislation, biofuel crops (as they compete with the livestock farmers for land) and environmental issues, which has resulted in substantially reduced profits for the community. In 2010, the average income for a farmer dropped by 27% compared to its value in 2003.
The Common Agricultural Policy (CAP) in the EU unevenly distributes subsidies to large farms and land owners while small- and medium-sized farms struggle to survive on less than minimum wage.
For example, in Spain, the top 18% of big farms received 76% of all subsidies and 37,000 family-run farms disappear each year. In addition, the livestock sector is faced with increasing legislation that, in time, will ban current methods for disposal of manure. Currently >90% of the 1,578 million tonnes of cow and pig manure produced per year are disposed of by being spread on fields as fertiliser. As manure contains high amounts of nitrogen and phosphorus, its disposal by this spreading method has become a problem.
Application of excessive amounts of manure to land can lead to surface and ground water
contamination through the accumulation of minerals in the soil. Nitrate and phosphate levels in many European waters are increasing to dangerous levels with over 70% of nitrate entering water from over-fertilisation of agricultural land. As a result, farmers in the EU are confronted with an increasing number of essential regulations and administration that limits the degree of freedom in farming, especially in intensive animal production. For example, the Nitrates Action Directive places a severe restriction on the quantity of organic manure that can be applied to land (170 kg N/ha/year) in addition to regulations forbidding land application during 4 months of the year and minimum storage periods of 6 months. In addition, the level of spreadlands currently available is inadequate for the amount of manure produced and would need to drastically increase in order to meet the limits set by the Nitrates Directive.
In order to meet vital legislation, livestock farmers may have to export the manure off the farm to landfill; this practice will expose the farming community to substantial increases in cost (>70% increase on current cost), due to landfill tax and transport costs. In addition export of manure off the farm is not always a viable alternative as transport of raw manure further than 15km is uneconomical due to its high water content (>70% by weight).
In order to meet on-farm nitrate and phosphate balance, the livestock sector has already been using low-protein animal feed, and low emissions techniques for the storage, handling and application of animal manure. These methods now used by farmers are proving expensive for the farming community and relatively inefficient. In addition improved farming practices alone will not be sufficient to meet the demanding environmental objectives for phosphates in surface waters as part of the European Nitrate Directive and Water Framework Directive, in which livestock manure loadings are limited to an overall farm limit of 170kg/ha total nitrogen on arable land; this is equivalent to limits for phosphorus of 19 kg/ha and 43 kg/ha respectively for cattle and pig manure.
Alternative methods for disposal of manure such as anaerobic digestion or gasification can be used for the conversion of manure into syngas or biogas for production of energy or use as a biofuel.
However these technologies require a minimum guaranteed tonnage to cover their high operating and capital cost. Therefore their operation involves transport of manure feedstocks from various farms to the operating site, increasing the risk of animal disease transmission between farms through cross-contamination from vehicle movements between farms and the centralised site.
Concern for the economic burden that implementation of existing and future legislation on nitrate and phosphate balances would place on the livestock farming community has driven Ashleigh Farms pig farmer with over 1500 sows that produce approximately 37000 pigs per year with further 10 fold of their counterpart Irish Farmers Associations to find an economical solution for the disposal of manure that would allow the livestock farming community to comply with important legislation while competing with cheap meat imports from the USA.
Our project, PlaGasMic has responded to an urgent need from the livestock farming community todevelop an environmentally-friendly method for disposal of animal manure such that the economic, competitive and legislative burdens on them may be eased. PlaGasMic involves the pyrolysis of manure using microwave induced plasma (MIP) technology allowing a rapid release of gases rich in hydrogen (‘syngas’). In addition we will collect a water-based liquid that will be subjected to electro-coagulation and filtration processes to obtain clean water suitable for farm cleaning, and additional salts with potential use as fertilisers.
Project Context and Objectives:
The Project concept
European SMEs operating in livestock farming (>2.21million) are under increasing pressure from supermarket purchasing powers, legislation, biofuel crops (as they compete with the livestock farmers for land) and environmental issues, which has resulted in substantially reduced profits for the community. In 2010, the average income for a farmer dropped by 27% compared to its value in 2003.
The Common Agricultural Policy (CAP) in the EU unevenly distributes subsidies to large farms and land owners while small- and medium-sized farms struggle to survive on less than minimum wage. For example, in Spain, the top 18% of big farms received 76% of all subsidies and 37,000 family-run farms disappear each year. In addition, the livestock sector is faced with increasing legislation that, in time, will ban current methods for disposal of manure. Currently >90% of the 1,578 million tonnes of cow and pig manure produced per year are disposed of by being spread on fields as fertiliser. As manure contains high amounts of nitrogen and phosphorus, its disposal by this spreading method has become a problem.
Application of excessive amounts of manure to land can lead to surface and ground water contamination through the accumulation of minerals in the soil. Nitrate and phosphate levels in many European waters are increasing to dangerous levels with over 70% of nitrate entering water from over-fertilisation of agricultural land. As a result, farmers in the EU are confronted with an increasing number of essential regulations and administration that limits the degree of freedom in farming, especially in intensive animal production. For example, the Nitrates Action Directive places a severe restriction on the quantity of organic manure that can be applied to land (170 kg N/ha/year) in addition to regulations forbidding land application during 4 months of the year and minimum storage periods of 6 months. In addition, the level of spreadlands currently available is inadequate for the amount of manure produced and would need to drastically increase in order to meet the limits set by the Nitrates Directive.
In order to meet vital legislation, livestock farmers may have to export the manure off the farm to landfill; this practice will expose the farming community to substantial increases in cost (>70% increase on current cost), due to landfill tax and transport costs. In addition export of manure off the farm is not always a viable alternative as transport of raw manure further than 15km is uneconomical due to its high water content (>70% by weight).
In order to meet on-farm nitrate and phosphate balance, the livestock sector has already been using low-protein animal feed and low emissions techniques for the storage, handling and application of animal manure. These methods now used by farmers are proving expensive for the farming community and relatively inefficient. In addition improved farming practices alone will not be sufficient to meet the demanding environmental objectives for phosphates in surface waters as part of the European Nitrate Directive and Water Framework Directive, in which livestock manure loadings are limited to an overall farm limit of 170kg/ha total nitrogen on arable land; this is equivalent to limits for phosphorus of 19 kg/ha and 43 kg/ha respectively for cattle and pig manure.
Alternative methods for disposal of manure such as anaerobic digestion or gasification can be used for the conversion of manure into syngas or biogas for production of energy or use as a biofuel. However these technologies require a minimum guaranteed tonnage to cover their high operating and capital cost. Therefore their operation involves transport of manure feed stocks from various farms to the operating site, increasing the risk of animal disease transmission between farms through cross-contamination from vehicle movements between farms and the centralised site.
Concern for the economic burden that implementation of existing and future legislation on nitrate and phosphate balances would place on the livestock farming community has driven Ashleigh Farms pig farmer with over 1500 sows that produce approximately 37000 pigs per year with further 10 fold of their counterpart Irish Farmers Associations to find an economical solution for the disposal of manure that would allow the livestock farming community to comply with important legislation while competing with cheap meat imports from the USA.
Our project, PlaGasMic will respond to an urgent need from the livestock farming community to develop an environmentally-friendly method for disposal of animal manure such that the economic, competitive and legislative burdens on them may be eased. PlaGasMic involves the pyrolysis of manure using microwave induced plasma (MIP) technology allowing a rapid release of gases rich in hydrogen (‘syngas’). In addition we will collect a water-based liquid that will be subjected to electro-coagulation and filtration processes to obtain clean water suitable for farm cleaning, and additional salts with potential use as fertilisers.
The main features of our technology are:
• A microwave plasma reactor that used to process animal manure. The reactor has two outputs – waste water containing nitrate and phosphate salts, and a hydrogen-rich gaseous mixture (syngas). The application of microwave induced plasma to animal manure for the production of syngas is novel and the best parameters will need to be experimentally determined.
• The use of microwaves as a pre-treatment methods to breakdown the contents of waste into rich liquid ideal “super soup” for speeding up the digestion process.
• The reactor consists of multiple microwave (MW) sources operating over a range of frequencies (2.45 GHz to 10 GHz) and power ratings. However, for industrial costing purposes and off shelf sources, it was recommended by the industrial p[partners to use sources operating at 2.45GHz.
• An electro-coagulation filtration system applied to the effluent in order to recover 0.7 to 0.9 litres of water per litre of manure with purity >99%. This process has allowed us to separate the nitrate and phosphate salts such that they may be used as fertilisers thereafter.
The main composition of this syngas will be 0.5% H2 and 7% CO for pig manure and 3% H2 and 42% CO for cow manure. This syngas has a calorific value of 142,000 J/g H2 and 10,107 J/g CO respectively and could be used directly in a gas-fired boiler unit (using the syngas produced as fuel) in order to heat water that could provide heat for the farm, or used directly in an engine for production of electricity which will be sold to the electricity grid.
In addition to the syngas this technology will generate 0.7 to 0.95 litres of effluent per litre of manure (depending on the moisture content of the manure). This effluent will be subjected to electro-coagulation and filtration systems producing water of 99% purity for farm cleaning in addition to nitrate and phosphate salts that could be used as fertilisers.
Scientific and technological objectives
Microwave heating can offer increased flexibility and control over traditional methods of heating, resulting from the instantaneous transfer or “coupling” of energy to molecules and ions. This results in systems that have greatly reduced thermal lag and consequently rapid heating and cooling rates can be achieved which can in part account for improvements in rate, yield and product selectivity.
Microwaves, electrical and magnetic field energies, are able to heat materials by two actions, namely dipole rotation and ionic conduction and both are able to absorb microwave energy by oscillating in the microwave field. Dipole materials have large dielectric constants and dielectric losses. Currently, the microwave source most commonly used is the fixed frequency 2.45GHz magnetron like the current house hold microwave ovens.
Although the use of 2.45GHz microwaves are reported to enhance the rate of chemical reactions or to produce a different product profile which can lead to higher yields, 2.45GHz is not necessarily the optimum frequency to use. For example, the Figure below shows the microwave dielectric loss for water, which represents power absorbed as a function of wavelength and temperature. For 2.45GHz the wavelength is 12.2cm and 11 as it dramatically decrease as the temperature increases. Hence the optimum operating frequency is not 2.45GHz but 10GHz (wavelength= 3cm) at room temperature but increases to 100GHz (wavelength= 3mm) at 100oC. Hence one of the focuses in this proposal is to deal with the Pigs/Cow waste physical properties of which the tuneable microwave source can maximise the microwave energy absorption.
Microwave Plasma, uses much focused energy with electrical field is about 10 fold higher in comparison with field generated by a conventional microwaves. Plasma gasification is a partial thermal degradation of a substance under sub-stoichiometric conditions (i.e. in the presence of oxygen but with insufficient oxygen to oxidise the fuel completely). The process uses high electrical field and high temperatures >4000 degree C to break down waste into its basic elemental composition, under controlled oxygen conditions, producing a synthesis gas and an inert vitrified slag.
Electro-coagulation is already used around the world to treat wastewater from mining, pulp and paper and metal processing industries and is highly effective in the removal of suspended and dissolved materials from solution; for example, phosphate levels in solution can be reduced by greater than 50% in one pass through the unit. However, the system has not been applied to the treatment of wastewater from a microwave plasma system and therefore will need further development.
The primary goal of the PlaGasMic project is to design, build and demonstrate a microwave plasma reactor integrated with electro-coagulation technology for continuous conversion of different types of manure into syngas for use as a fuel. In addition to the syngas, this technology managed to generate 0.7 to 0.9 litres of effluent per litre of manure (depending on the moisture content of the manure). This effluent was subjected to electro-coagulation and filtration to produce clean water for use in the farm in addition to nitrate and phosphate salts that could be used as fertilisers.
Scientific Objectives:
WP1: To investigate and characterise the effects of temperature (600 to 1000°C), time of reaction (hours to <2 days), range of operating frequency (2.45 to 10 GHz) and power applied to manure with moisture content. To research self-tuning of microwave sources to operate at various frequencies ranging from 2.45 to 10 GHz and automatic modulation of power levels to maintain optimisation.
WP2: To determine the range of current density to apply in the electro-coagulation process to the wastewater produced from the microwave process in order to achieve water with <0.2% suspended solids.
Technical Objectives:
WP1: To measure the dielectric properties of manure with water content between 70 and 95% across a range of frequencies (2.45 GHz to 10 GHz).
WP3: Design and build a microwave plasma reactor in which a single cavity will be used for all frequencies in the range of 2.45 to 10 GHz allowing multimode resonance conditions to be maintained at all times. In this system coupling waveguides will be used to allow any microwave source (i.e. magnetrons and travelling waves tubes) to be attached over the cavity.
WP4: Design and build an automated microwave plasma monitoring system in which software analysis will identify the salient parameters for each sensor (based on temporal analysis, spectrum analysis and response times) which will be used to map the parameters against the moisture content in the manure.
WP5: Design and build an electro-coagulation filtration system capable of treating up to 8 litres of processed effluent per minute. This system designed to recover 0.7 to 0.9 litres of water (<1% suspended solid) per litre of manure process.
WP1-6: Design, build and demonstrate a microwave plasma reactor for continuous processing (capacity of 3000 litres a day) and with an energy consumption of <7 kW per day, capable of producing up to 5 to 30 g of H2 per litre of manure processed.
Integrated Objectives:
WP7: Validation of performance of the prototype model at test sites through
• Verification of yield of syngas and clean water from different types of manure.
• Verification of time of reaction in relation to yield of syngas and water recovery.
• Verification of temperature of reaction in relation to yield of syngas and water recovery.
• Verification of energy consumption in relation to yield of syngas and water recovery.
Economic Objectives:
WP1-9: The final system has tested with expectation of a life expectancy of 10 years and can be priced at €100,000 (capital cost) compared to centralised facilities that cost over €4.5 million. We estimate that with a throughput of 750,000 litres per year (1000 units of live stock) and operating costs of <10% the capital cost per year (approx. €2200) with a quick payback period will be achieved. This is more than 25 times cheaper than a traditional anaerobic digestion system. The main capital cost is related to the microwave source and its operating power.
Although the payback of our technology is very attractive the main objective of PlaGasMic project is to provide a solution for disposal of manure to all sizes of livestock farms.
In order to achieve a solution within reach of small sized farms our technology will be modular. The number of reactors in use will be dependable on the size of the livestock farm. One reactor will be capable of treating up to 300,000 litres of manure per year (suitable for a farm with less than 500 heads of livestock). The effluent generated by the microwave plasma reactors will be fed into one electro-coagulation unit and an additional plasma source in order to recover the nitrogen and phosphorus salts and produce water for farm cleaning use.
During the project, the industrial partner’s option was to design a mobile compact system that meeting the needs for the farmers with multi components modules. In addition as the PlaGasMic system has a small footprint with a scale out potential to suit the industrial need. This can be in the form of using only one microwave source with high power of 30kW or multiple ones of 1kW unit similar to that of house hold microwave oven. Thus making our technology to have a massive potential over the current technologies which could be mobile between farms. Groups of small farmers will be able to buy a system between them and move the unit from one farm to another when it is needed. In addition we will consider the possibility of renting the technology to farmers with less than 1000 units of livestock.
Project Results:
Please see the attached summary report.
Potential Impact:
Please see the attached the impact report.
