Sustainability 2022 , 14 , 4669
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The difference between the results in terms of individual syngas composition, LHV of syngas, CCE , and CGE predicted through the developed model and experimental outcomes generate a deviation, which is calculated through Equation (2):
Simulation result − Experimental result Experimental result · 100,
Deviation ( % )=
(2)
The average deviation of the overall syngas composition is calculated considering the deviations of the individual components according to Equation (3):
Average Deviation ( % )= 1
n i = 1 | Deviation | ,
n ∑
(3)
where, n represents the number of syngas components considered during gasification model calibration and validation. 2.3. Assessment of Process Performance Process performances of WP–DIS pellets conversion to syngas through gasification are evaluated by assessing syngas LHV , CGE , and CCE as well as net power ( . P net ) available from the conversion process. The LHV of syngas depends on its composition and is calculated using Equation (4) [59]:
3 )= 0.108 y
LHV syng ( MJ/Nm
H 2 + 0.126 y CO + 0.358 y CH 4 ,
(4)
where, y H 2 , y CO , and y CH 4 denote the volume fraction of H 2 , CO, andCH 4 , respectively, present in syngas. The ratio between the energy flow rate of the syngas and that of the material fed to the gasifier is defined as CGE and is evaluated according to Equation (5) [23]:
LHV syng · . LHV fed ·
v syng . m fed ·
CGE ( % )=
100,
(5)
3 and WP–DIS pellet
where, LHV syng and LHV fed represent the LHV of syngas in MJ/Nm
in MJ/kg, respectively, whereas .
. m fed stand for the volumetric flow rate of syngas
v syng and
(Nm 3 /h) and mass flow rate of WP–DIS pellet (kg/h). The ratio of carbon flow rate by weight between the product streams (syngas) and reactant (WP–DIS pellet) is the CCE that is assessed by Equation (6) [23]:
. v syng
12 22.4 ·
CCE ( % )=
· 100,
(6)
. m fed · C% · ∑ 5
i = 1 n i · y i
where, i represents the carbon-containing constituent present in the syngas, C% is the weight fraction of carbon present in the WP–DIS pellet, n i is the carbon number, and y i is the fraction of i compound by volume in syngas (i.e.: C 1 –C 5 ). The difference between primary power available from the generated syngas and that required to complete air preheating is defined . P net and is stated in Equation (7): . P net = . P syng − . P prht , (7) where, . P syng is the primary power obtained from syngas and . P prht denotes the power required to complete air preheating.
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