The Experts below are selected from a list of 4698 Experts worldwide ranked by ideXlab platform
Jerry D Murphy - One of the best experts on this subject based on the ideXlab platform.
-
can acid pre treatment enhance biohydrogen and Biomethane production from grass silage in single stage and two stage fermentation processes
Energy Conversion and Management, 2019Co-Authors: Che Deng, Ju Cheng, Jerry D MurphyAbstract:Abstract Grass silage is an excellent feedstock for biofuel production, however, the recalcitrant cellulosic structure may limit its biodegradability. In this study, the effect of acid pre-treatment with mild thermal treatment conditions on biohydrogen and Biomethane production from grass silage was assessed through single-stage (CH4) and two-stage (H2 + CH4) fermentation. Microstructural characterisation showed that pre-treatment significantly reduced the recalcitrance and enlarged the specific area of grass silage. The optimal pre-treatment with 2% H2SO4 at 135 °C for 15 min achieved a total reducing sugar yield of 333.79 mg/g volatile solid (VS) of grass silage. The pre-treated silage led to a hydrogen yield of 68.26 ml/g VS in the first stage hydrogen fermentation, a 3-fold increase compared to untreated silage. The production of volatile fatty acids accordingly increased by 29.2%. In the second stage anaerobic digestion, untreated silage achieved the highest Biomethane yield of 392.84 ml/g VS, with a corresponding highest total energy conversion efficiency of 83.5%. Due to a lower Biomethane yield, the pre-treated silage presented a decreased total energy efficiency of 68.4%. In comparison, single-stage anaerobic digestion showed lower energy conversion efficiencies of 49.7% and 54.2% for the pre-treated and untreated silage, respectively. Despite the slight decrease in CH4 yield, the pre-treatment led to decreased energy consumption for the operation of anaerobic digestion processes due to the shorter digestion duration.
-
cascading Biomethane energy systems for sustainable green gas production in a circular economy
Bioresource Technology, 2017Co-Authors: David M Wall, Jerry D Murphy, Shane McdonaghAbstract:Abstract Biomethane is a flexible energy vector that can be used as a renewable fuel for both the heat and transport sectors. Recent EU legislation encourages the production and use of advanced, third generation biofuels with improved sustainability for future energy systems. The integration of technologies such as anaerobic digestion, gasification, and power to gas, along with advanced feedstocks such as algae will be at the forefront in meeting future sustainability criteria and achieving a green gas supply for the gas grid. This paper explores the relevant pathways in which an integrated Biomethane industry could potentially materialise and identifies and discusses the latest biotechnological advances in the production of renewable gas. Three scenarios of cascading Biomethane systems are developed.
-
boosting Biomethane yield and production rate with graphene the potential of direct interspecies electron transfer in anaerobic digestion
Bioresource Technology, 2017Co-Authors: Ju Cheng, Jiabei Zhang, Junhu Zhou, Jerry D MurphyAbstract:Interspecies electron transfer between bacteria and archaea plays a vital role in enhancing energy efficiency of anaerobic digestion (AD). Conductive carbon materials (i.e. graphene nanomaterial and activated charcoal) were assessed to enhance AD of ethanol (a key intermediate product after acidogenesis of algae). The addition of graphene (1.0g/L) resulted in the highest Biomethane yield (695.0±9.1mL/g) and production rate (95.7±7.6mL/g/d), corresponding to an enhancement of 25.0% in Biomethane yield and 19.5% in production rate. The ethanol degradation constant was accordingly improved by 29.1% in the presence of graphene. Microbial analyses revealed that electrogenic bacteria of Geobacter and Pseudomonas along with archaea Methanobacterium and Methanospirillum might participate in direct interspecies electron transfer (DIET). Theoretical calculations provided evidence that graphene-based DIET can sustained a much higher electron transfer flux than conventional hydrogen transfer.
-
assessing the total theoretical and financially viable resource of Biomethane for injection to a natural gas network in a region
Applied Energy, 2017Co-Authors: Richard Oshea, David M Wall, James D Owne, Ia Kilgallo, Jerry D MurphyAbstract:The total theoretical Biomethane resource of cattle slurry and grass silage in Ireland was estimated using the most up to date spatially explicit data available. The cattle slurry resource (9.6PJ) was predominantly found in southern and north-eastern regions while the grass silage resource (128.4PJ) was more concentrated in western regions. The total Biomethane resource of cattle slurry and grass silage was equivalent to 6% and 76% of total natural gas consumption in Ireland in 2014/15, respectively. A sequential optimisation model was run to determine where to source cattle slurry and grass silage from, for 42 potential Biomethane plant locations in Ireland. The concept was to maximise plant net present value (NPV) and develop locations in order of plant profitability. The impact of plant size, grass silage price, volatile solids ratio (VSR) of grass silage to cattle slurry, and incentive per unit energy of Biomethane was assessed in 81 separate scenarios. The results indicated that total Biomethane production from plants with a positive NPV ranged from 3.51PJ/a to 12.19PJ/a, considerably less than the total resource. The levelised cost of energy (LCOE) of plants was also calculated and ranged from ca. 50.2€/MWh to ca. 109€/MWh depending on the various plant parameters. LCOE decreased with increased plant size and ratio of grass silage to cattle slurry. The relationship between grass silage price and LCOE was assessed. In the median scenario (33€/twwt grass silage, VSR of 4, 75,000twwt/a plant size, 60€/MWh incentive) cattle slurry was sourced within 6.4km of the facility while grass silage was sourced within 10.5km of the facility. A high level assessment of the carbon dioxide intensity of Biomethane from the median scenario was conducted and showed a potential greenhouse gas reduction of 74–79% when compared to natural gas.
-
modelling a demand driven biogas system for production of electricity at peak demand and for production of Biomethane at other times
Bioresource Technology, 2016Co-Authors: Richard Oshea, David M Wall, Jerry D MurphyAbstract:Abstract Four feedstocks were assessed for use in a demand driven biogas system. Biomethane potential (BMP) assays were conducted for grass silage, food waste, Laminaria digitata and dairy cow slurry. Semi-continuous trials were undertaken for all feedstocks, assessing biogas and Biomethane production. Three kinetic models of the semi-continuous trials were compared. A first order model most accurately correlated with gas production in the pulse fed semi-continuous system. This model was developed for production of electricity on demand, and Biomethane upgrading. The model examined a theoretical grass silage digester that would produce 435 kW e in a continuous fed system. Adaptation to demand driven biogas required 187 min to produce sufficient methane to run a 2 MW e combined heat and power (CHP) unit for 60 min. The upgrading system was dispatched 71 min following CHP shutdown. Of the biogas produced 21% was used in the CHP and 79% was used in the upgrading system.
David M Wall - One of the best experts on this subject based on the ideXlab platform.
-
cascading Biomethane energy systems for sustainable green gas production in a circular economy
Bioresource Technology, 2017Co-Authors: David M Wall, Jerry D Murphy, Shane McdonaghAbstract:Abstract Biomethane is a flexible energy vector that can be used as a renewable fuel for both the heat and transport sectors. Recent EU legislation encourages the production and use of advanced, third generation biofuels with improved sustainability for future energy systems. The integration of technologies such as anaerobic digestion, gasification, and power to gas, along with advanced feedstocks such as algae will be at the forefront in meeting future sustainability criteria and achieving a green gas supply for the gas grid. This paper explores the relevant pathways in which an integrated Biomethane industry could potentially materialise and identifies and discusses the latest biotechnological advances in the production of renewable gas. Three scenarios of cascading Biomethane systems are developed.
-
assessing the total theoretical and financially viable resource of Biomethane for injection to a natural gas network in a region
Applied Energy, 2017Co-Authors: Richard Oshea, David M Wall, James D Owne, Ia Kilgallo, Jerry D MurphyAbstract:The total theoretical Biomethane resource of cattle slurry and grass silage in Ireland was estimated using the most up to date spatially explicit data available. The cattle slurry resource (9.6PJ) was predominantly found in southern and north-eastern regions while the grass silage resource (128.4PJ) was more concentrated in western regions. The total Biomethane resource of cattle slurry and grass silage was equivalent to 6% and 76% of total natural gas consumption in Ireland in 2014/15, respectively. A sequential optimisation model was run to determine where to source cattle slurry and grass silage from, for 42 potential Biomethane plant locations in Ireland. The concept was to maximise plant net present value (NPV) and develop locations in order of plant profitability. The impact of plant size, grass silage price, volatile solids ratio (VSR) of grass silage to cattle slurry, and incentive per unit energy of Biomethane was assessed in 81 separate scenarios. The results indicated that total Biomethane production from plants with a positive NPV ranged from 3.51PJ/a to 12.19PJ/a, considerably less than the total resource. The levelised cost of energy (LCOE) of plants was also calculated and ranged from ca. 50.2€/MWh to ca. 109€/MWh depending on the various plant parameters. LCOE decreased with increased plant size and ratio of grass silage to cattle slurry. The relationship between grass silage price and LCOE was assessed. In the median scenario (33€/twwt grass silage, VSR of 4, 75,000twwt/a plant size, 60€/MWh incentive) cattle slurry was sourced within 6.4km of the facility while grass silage was sourced within 10.5km of the facility. A high level assessment of the carbon dioxide intensity of Biomethane from the median scenario was conducted and showed a potential greenhouse gas reduction of 74–79% when compared to natural gas.
-
modelling a demand driven biogas system for production of electricity at peak demand and for production of Biomethane at other times
Bioresource Technology, 2016Co-Authors: Richard Oshea, David M Wall, Jerry D MurphyAbstract:Abstract Four feedstocks were assessed for use in a demand driven biogas system. Biomethane potential (BMP) assays were conducted for grass silage, food waste, Laminaria digitata and dairy cow slurry. Semi-continuous trials were undertaken for all feedstocks, assessing biogas and Biomethane production. Three kinetic models of the semi-continuous trials were compared. A first order model most accurately correlated with gas production in the pulse fed semi-continuous system. This model was developed for production of electricity on demand, and Biomethane upgrading. The model examined a theoretical grass silage digester that would produce 435 kW e in a continuous fed system. Adaptation to demand driven biogas required 187 min to produce sufficient methane to run a 2 MW e combined heat and power (CHP) unit for 60 min. The upgrading system was dispatched 71 min following CHP shutdown. Of the biogas produced 21% was used in the CHP and 79% was used in the upgrading system.
-
optimisation of digester performance with increasing organic loading rate for mono and co digestion of grass silage and dairy slurry
Bioresource Technology, 2014Co-Authors: Eoin Allen, Barbara Straccialini, David M Wall, Padraig Okiely, Jerry D MurphyAbstract:Abstract This study investigated the feasibility of mono-digesting grass silage, dairy slurry and the co-digestion of the two substrates at a range of concentrations with a specific focus on digester performance while increasing organic loading rate (OLR). The results show that the higher the proportion of grass silage in the substrate mix the higher the specific methane yield (SMY) achieved. Optimum conditions were assessed for 100% grass silage at an OLR of 3.5 kg VS m−3 d−1 generating a SMY of 398 L CH4 kg−1 VS equating to a Biomethane efficiency of 1.0. For co-digestion of grass silage with 20% dairy slurry the optimum condition was noted at an OLR of 4.0 kg VS m−3 d−1 generating a SMY of 349 L CH4 kg−1 VS and a Biomethane efficiency of 1.01. Hydraulic retention times of less than 20 days proved to be a limiting factor in the operation of farm digesters.
-
The effect of trace element addition to mono-digestion of grass silage at high organic loading rates.
Bioresource Technology, 2014Co-Authors: David M Wall, Eoin Allen, Barbara Straccialini, Padraig O'kiely, Jerry D MurphyAbstract:Abstract This study investigated the effect of trace element addition to mono-digestion of grass silage at high organic loading rates. Two continuous reactors were compared. The first mono-digested grass silage whilst the second operated in co-digestion, 80% grass silage with 20% dairy slurry (VS basis). The reactors were run for 65 weeks with a further 5 weeks taken for trace element supplementation for the mono-digestion of grass silage. The co-digestion reactor reported a higher Biomethane efficiency (1.01) than mono-digestion (0.90) at an OLR of 4.0 kg VS m−3 d−1 prior to addition of trace elements. Addition of cobalt, iron and nickel, led to an increase in the SMY in mono-digestion of grass silage by 12% to 404 L CH4 kg−1 VS and attained a Biomethane efficiency of 1.01.
Vanessa Ripoll - One of the best experts on this subject based on the ideXlab platform.
-
improvement of Biomethane potential of sewage sludge anaerobic co digestion by addition of sherry wine distillery wastewater
Journal of Cleaner Production, 2020Co-Authors: Vanessa Ripoll, Cristina Agabogarcia, Montserrat Perez, R SoleraAbstract:Abstract Co-digestion of sewage sludge (SS) with other unusually treated residues has been reported as an efficient method to improve Biomethane production. In this work, Sherry-wine distillery wastewater (SW-DW) has been proposed as co-substrate in order to increase Biomethane production and as a breakthrough solution in the management of both types of waste. In order to achieve this goal, different SS:SW-DW mixtures were employed as substrates in Biomethane Potential (BMP) tests. The biodegradability and Biomethane potential of each mixture was determined selecting the optimal co-substrate ratio. Results showed that the addition of SW-DW as a co-substrate improves the anaerobic digestion of SS in a proportionally way in terms of CODs and Biomethane production The optimal co-substrates ratio was 50:50 of SS:SW-DW obtaining %VSremoval = 54.5%; YCH4 = 225.1 L CH4/kgsv or 154 L CH4/kgCODt and microbial population of 5.5 times higher than sole SS. In this case, %VSremoval = 48.1%; YCH4 = 183 L CH4/kgsv or 135 L CH4/kgCODt. The modified Gompertz equation was used for the kinetic modelling of biogas production with successful fitting results (r2 = 0.99). In this sense, at optimal conditions, the maximum productivity reached at an infinite digestion time was ( Y CH 4 MAX ) = 229 ± 5.0 NL/kgSV; the specific constant was K = 25.0 ± 2.3 NL/kgSV·d and the lag phase time constant was (λ) = 2.49 ± 0.19.
Alan J Guwy - One of the best experts on this subject based on the ideXlab platform.
-
an evaluation of the policy and techno economic factors affecting the potential for biogas upgrading for transport fuel use in the uk
Energy Policy, 2011Co-Authors: Tim Patterson, Sandra Esteves, Richard M Dinsdale, Alan J GuwyAbstract:Gaseous biofuels including Biomethane, which has been shown to be more environmentally beneficial than liquid biofuels, should contribute to meeting the challenging UK targets set for the supplying of biofuels to the road transport fuel market. Under the Renewable Transport Fuel Obligations the financial incentives for the supply of biofuels have been volatile, e.g. 2008/2009 saw Renewable Transport Fuel Certificate values fall to zero. Any shortfall from the maximum value has significant implications for all biofuels. It is demonstrated that Biomethane can be produced at a cost which is competitive with liquid biofuels and fossil fuels within the UK. Technologies such as water scrubbing, pressure swing adsorption and physical and chemical absorption are available to upgrade biogas generated by anaerobic digestion of organic wastes to transport fuel quality, and technologies such as membrane separation and cryogenic distillation are being modified for such an application. The manufacture and sale of Biomethane as a transport fuel is also financially competitive with Combined Heat and Power. One limiting factor may be the additional cost of purchasing and maintaining Biomethane fuelled vehicles. Support in this area could lead to the rapid expansion of Biomethane transport fuel infrastructure and bring significant long term environmental and economic advantages.
R Solera - One of the best experts on this subject based on the ideXlab platform.
-
improvement of Biomethane potential of sewage sludge anaerobic co digestion by addition of sherry wine distillery wastewater
Journal of Cleaner Production, 2020Co-Authors: Vanessa Ripoll, Cristina Agabogarcia, Montserrat Perez, R SoleraAbstract:Abstract Co-digestion of sewage sludge (SS) with other unusually treated residues has been reported as an efficient method to improve Biomethane production. In this work, Sherry-wine distillery wastewater (SW-DW) has been proposed as co-substrate in order to increase Biomethane production and as a breakthrough solution in the management of both types of waste. In order to achieve this goal, different SS:SW-DW mixtures were employed as substrates in Biomethane Potential (BMP) tests. The biodegradability and Biomethane potential of each mixture was determined selecting the optimal co-substrate ratio. Results showed that the addition of SW-DW as a co-substrate improves the anaerobic digestion of SS in a proportionally way in terms of CODs and Biomethane production The optimal co-substrates ratio was 50:50 of SS:SW-DW obtaining %VSremoval = 54.5%; YCH4 = 225.1 L CH4/kgsv or 154 L CH4/kgCODt and microbial population of 5.5 times higher than sole SS. In this case, %VSremoval = 48.1%; YCH4 = 183 L CH4/kgsv or 135 L CH4/kgCODt. The modified Gompertz equation was used for the kinetic modelling of biogas production with successful fitting results (r2 = 0.99). In this sense, at optimal conditions, the maximum productivity reached at an infinite digestion time was ( Y CH 4 MAX ) = 229 ± 5.0 NL/kgSV; the specific constant was K = 25.0 ± 2.3 NL/kgSV·d and the lag phase time constant was (λ) = 2.49 ± 0.19.
