Energy recovery from human faeces via gasification: a thermodynamic equilibrium modelling approach

T. Somorin, K. Patchigolla, S.T. Wagland, B. Fidalgo, A. Kolios, E. McAdam, A. Parker, L. Williams, S. Tyrrel, E. Cartmell

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Non-sewered sanitary systems (NSS) are emerging as one of the solutions to poor sanitation because of the limitations of the conventional flush toilet. These new sanitary systems are expected to safely treat faecal waste and operate without external connections to a sewer, water supply or energy source. The Nano Membrane Toilet (NMT) is a unique domestic-scale sanitary solution currently being developed to treat human waste on-site. This toilet will employ a small-scale gasifier to convert human faeces into products of high energy value. This study investigated the suitability of human faeces as a feedstock for gasification. It quantified the recoverable exergy potential from human faeces and explored the optimal routes for thermal conversion, using a thermodynamic equilibrium model. Fresh human faeces were found to have approximately 70-82 wt.% moisture and 3-6 wt.% ash. Product gas resulting from a typical dry human faeces (0 wt.% moisture) had LHV and exergy values of 17.2 MJ/kg and 24 MJ/kg respectively at optimum equivalence ratio of 0.31, values that are comparable to wood biomass. For suitable conversion of moist faecal samples, near combustion operating conditions are required, if an external energy source is not supplied. This is however at 5% loss in the exergy value of the gas, provided both thermal heat and energy of the gas are recovered. This study shows that the maximum recoverable exergy potential from an average adult moist human faeces can be up to 15 MJ/kg, when the gasifier is operated at optimum equivalence ratio of 0.57, excluding heat losses, distribution or other losses that result from operational activities.

LanguageEnglish
Pages364-376
Number of pages13
JournalEnergy Conversion and Management
Volume118
Early online date8 Apr 2016
DOIs
Publication statusPublished - 15 Jun 2016

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Exergy
Gasification
Thermodynamics
Recovery
Ashes
Moisture
Gases
Sanitation
Sewers
Heat losses
Water supply
Feedstocks
Wood
Biomass
Membranes
Hot Temperature

Keywords

  • biomass
  • exergy analysis
  • gasification
  • nano membrane toilet
  • non-sewered sanitary systems

Cite this

Somorin, T. ; Patchigolla, K. ; Wagland, S.T. ; Fidalgo, B. ; Kolios, A. ; McAdam, E. ; Parker, A. ; Williams, L. ; Tyrrel, S. ; Cartmell, E. / Energy recovery from human faeces via gasification : a thermodynamic equilibrium modelling approach. In: Energy Conversion and Management. 2016 ; Vol. 118. pp. 364-376.
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Somorin, T, Patchigolla, K, Wagland, ST, Fidalgo, B, Kolios, A, McAdam, E, Parker, A, Williams, L, Tyrrel, S & Cartmell, E 2016, 'Energy recovery from human faeces via gasification: a thermodynamic equilibrium modelling approach' Energy Conversion and Management, vol. 118, pp. 364-376. https://doi.org/10.1016/j.enconman.2016.04.005

Energy recovery from human faeces via gasification : a thermodynamic equilibrium modelling approach. / Somorin, T.; Patchigolla, K.; Wagland, S.T.; Fidalgo, B.; Kolios, A.; McAdam, E.; Parker, A.; Williams, L.; Tyrrel, S.; Cartmell, E.

In: Energy Conversion and Management, Vol. 118, 15.06.2016, p. 364-376.

Research output: Contribution to journalArticle

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T1 - Energy recovery from human faeces via gasification

T2 - Energy Conversion and Management

AU - Somorin, T.

AU - Patchigolla, K.

AU - Wagland, S.T.

AU - Fidalgo, B.

AU - Kolios, A.

AU - McAdam, E.

AU - Parker, A.

AU - Williams, L.

AU - Tyrrel, S.

AU - Cartmell, E.

PY - 2016/6/15

Y1 - 2016/6/15

N2 - Non-sewered sanitary systems (NSS) are emerging as one of the solutions to poor sanitation because of the limitations of the conventional flush toilet. These new sanitary systems are expected to safely treat faecal waste and operate without external connections to a sewer, water supply or energy source. The Nano Membrane Toilet (NMT) is a unique domestic-scale sanitary solution currently being developed to treat human waste on-site. This toilet will employ a small-scale gasifier to convert human faeces into products of high energy value. This study investigated the suitability of human faeces as a feedstock for gasification. It quantified the recoverable exergy potential from human faeces and explored the optimal routes for thermal conversion, using a thermodynamic equilibrium model. Fresh human faeces were found to have approximately 70-82 wt.% moisture and 3-6 wt.% ash. Product gas resulting from a typical dry human faeces (0 wt.% moisture) had LHV and exergy values of 17.2 MJ/kg and 24 MJ/kg respectively at optimum equivalence ratio of 0.31, values that are comparable to wood biomass. For suitable conversion of moist faecal samples, near combustion operating conditions are required, if an external energy source is not supplied. This is however at 5% loss in the exergy value of the gas, provided both thermal heat and energy of the gas are recovered. This study shows that the maximum recoverable exergy potential from an average adult moist human faeces can be up to 15 MJ/kg, when the gasifier is operated at optimum equivalence ratio of 0.57, excluding heat losses, distribution or other losses that result from operational activities.

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KW - biomass

KW - exergy analysis

KW - gasification

KW - nano membrane toilet

KW - non-sewered sanitary systems

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