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Energy balance of biogas production from microalgae: effect of harvesting method, multiple raceways, scale of plant and combined heat and power generation

Energy balance of biogas production from microalgae: effect of harvesting method, multiple raceways, scale of plant and combined heat and power generation
Energy balance of biogas production from microalgae: effect of harvesting method, multiple raceways, scale of plant and combined heat and power generation
A previously-developed mechanistic energy balance model for production of biogas from the anaerobic digestion of microalgal biomass grown in open raceway systems was used to consider the energetic viability of a number of scenarios, and to explore some of the most critical parameters
affecting net energy production. The output demonstrated that no single harvesting method of those considered (centrifugation, settlement or flocculation) produced an energy output sufficiently
greater than operational energy inputs to make microalgal biogas production energetically viable.
Combinations of harvesting methods could produce energy outputs 2.3–3.4 times greater than the operational energy inputs. Electrical energy to power pumps, mixers and harvesting systems was 5–8 times greater than the heating energy requirement. If the energy to power the plant is generated
locally in a combined heat and power unit, a considerable amount of “low grade” heat will be available that is not required by the process, and for the system to show a net operational energy return this must be exploited. It is concluded that the production of microalgal biogas may be energetically viable, but it is dependent on the effective use of the heat generated by the combustion
of biogas in combined heat and power units to show an operational energy return.
Microalgae, Algae, Bioenergy, Anaerobic digestion, energy balance
1-15
Milledge, John J
89f742f7-2304-43e9-97d7-9426a19310ad
Heaven, Sonia
f25f74b6-97bd-4a18-b33b-a63084718571
Milledge, John J
89f742f7-2304-43e9-97d7-9426a19310ad
Heaven, Sonia
f25f74b6-97bd-4a18-b33b-a63084718571

Milledge, John J and Heaven, Sonia (2017) Energy balance of biogas production from microalgae: effect of harvesting method, multiple raceways, scale of plant and combined heat and power generation. Journal of Marine Science and Environment, 5 (1), 1-15. (doi:10.3390/jmse5010009).

Record type: Article

Abstract

A previously-developed mechanistic energy balance model for production of biogas from the anaerobic digestion of microalgal biomass grown in open raceway systems was used to consider the energetic viability of a number of scenarios, and to explore some of the most critical parameters
affecting net energy production. The output demonstrated that no single harvesting method of those considered (centrifugation, settlement or flocculation) produced an energy output sufficiently
greater than operational energy inputs to make microalgal biogas production energetically viable.
Combinations of harvesting methods could produce energy outputs 2.3–3.4 times greater than the operational energy inputs. Electrical energy to power pumps, mixers and harvesting systems was 5–8 times greater than the heating energy requirement. If the energy to power the plant is generated
locally in a combined heat and power unit, a considerable amount of “low grade” heat will be available that is not required by the process, and for the system to show a net operational energy return this must be exploited. It is concluded that the production of microalgal biogas may be energetically viable, but it is dependent on the effective use of the heat generated by the combustion
of biogas in combined heat and power units to show an operational energy return.

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energy balance of biogas production from microalgae - Accepted Manuscript
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Accepted/In Press date: 18 January 2017
e-pub ahead of print date: 25 January 2017
Keywords: Microalgae, Algae, Bioenergy, Anaerobic digestion, energy balance

Identifiers

Local EPrints ID: 425978
URI: http://eprints.soton.ac.uk/id/eprint/425978
PURE UUID: 17c9185a-8dd3-4223-a410-1dde692fa42c
ORCID for Sonia Heaven: ORCID iD orcid.org/0000-0001-7798-4683

Catalogue record

Date deposited: 08 Nov 2018 17:30
Last modified: 07 Oct 2020 01:37

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