Modelling of autogenerative high-pressure anaerobic digestion in a batch reactor for the production of pressurised biogas

Table 6 Parameters used in ADM1 simulations in the batch reactor [29, 62,63,64]

Parameter	Expression	Value	Unit
C_ac	Carbon content of acetate	0.0313	kmol C (kg COD)⁻¹
C_CH4	Carbon content of methane	0.0156	kmol C (kg COD)⁻¹
K_a,ac	Acid dissociation constant of acetate	1.738∙10^–5	mol L⁻¹
K_a,CO2	Acid dissociation constant of CO₂ at temperature 303 K	4.700∙10^–7	mol L⁻¹
k_A/Bac	Acid–base kinetic constant of acetate	1∙10¹⁰	L mol⁻¹ d⁻¹
k_A/Bco2	Acid–base kinetic constant of CO₂	1∙10¹⁰	L mol⁻¹ d⁻¹
k_dec,Xac	First-order decay rate	0.0200–0.0400	d⁻¹
K_H,CH4	Henry’s law coefficient of CH₄ at temperature 303 K	0.0013	mol L⁻¹ bar⁻¹
K_H,CO2	Henry’s law coefficient of CO₂ at temperature 303 K	0.0308	mol L⁻¹ bar⁻¹
k_La	Overall gas–liquid mass transfer coefficient	200*	d⁻¹
k_m,ac	Monod maximum specific uptake rate for acetate	4.100–7.800	kg COD kg COD ⁻¹ d⁻¹
K_S,ac	Half-saturation value for acetate	0.0500–0.600	kg COD m⁻³
K_w	Ion constant for water	1.450∙10^–14	mol L⁻¹
R	Ideal gas constant	0.0831	bar L mol⁻¹ K⁻¹
T_base	Absolute temperature in standard condition	298.15	K
T_op	Absolute temperature in digester	303.15	K
Y_ac	Yield of biomass on acetate	0.0500	–

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