THE ROLE OF CHAR FORMATION IN EQUILIBRIUM MODELING OF GASIFICATION PROCESSES

Ramos, Vinícius F.; Costa Junior, Esly F. da; Costa, Andréa O. S. da

doi:10.1590/1809-4430-Eng.Agric.v40n2p139-145/2020

Acessibilidade / Reportar erro

Brasil

Español English

sumário « anterior atual seguinte »

Sumário

Scientific Paper, Energy Systems • Eng. agríc. (Online) 40 (2) • Mar-Apr 2020 • https://doi.org/10.1590/1809-4430-Eng.Agric.v40n2p139-145/2020 copy

THE ROLE OF CHAR FORMATION IN EQUILIBRIUM MODELING OF GASIFICATION PROCESSES

Authorship SCIMAGO INSTITUTIONS RANKINGS

ABSTRACT

This work aims to develop and validate a model based on chemical equilibrium to predict the composition of syngas produced by gasification of woody biomass (sawdust). The model uses Gibbs Energy minimization to evaluate the composition of the system in chemical equilibrium. The results are validated by comparison between experimental data from a gasification experiment and those of other similar models in the literature. The study shows good agreement among experimental results and elucidates the role of solid unburned carbon in such systems, which is present in considerable amount. It can be concluded that equilibrium models can be used to predict carbon conversion in gasification systems.

KEYWORDS
char formation; gasification; Gibbs energy minimization; modeling

Input values	Altafini et al. (2003)Altafini CR, Wander PR, Barreto RM (2003) Prediction of the working parameters of a wood waste gasifier through an equilibrium model. Energy Conversion and Management 44:2763-2777. DOI: http://dx.doi.org/10.1016/S0196-8904(03)00025-6 http://dx.doi.org/10.1016/S0196-8904(03)...
Carbon (wt%)	52.05
Hydrogen (wt%)	6.08
Oxygen (wt%)	41.59
Nitrogen (wt%)	0.28
Higher heating value (MJ/kg)	20.4
Moisture content (wt%, waf)	10.0
Biomass feed rate (kg/h)	12.6
Air/biomass mass ratio (kg_AIR/kg_BM)	1.96
Gasification temperature (K)	1073

Species	n_i (Equations 1 and 10)	n_i (Equations 2 and 10)	n_i (Equations 1 and 13)	n_i (Equations 2 and 13)
CH₄	0.3	0	0.11	0.04
CO	106.26	5.8	106.58	77.26
CO₂	32.11	44.03	31.98	40.32
H₂	90.53	14.5	90.96	78.47
H₂O	25.35	101.98	25.29	37.95
N₂	165.52	165.52	165.52	165.52
C(s)	-	88.84	-	21.07
n_tot	420.07	420.67	420.44	420.63

	Experimental values	Models by other authors			Models developed in this study
	1 (Altafini et al., 2003Altafini CR, Wander PR, Barreto RM (2003) Prediction of the working parameters of a wood waste gasifier through an equilibrium model. Energy Conversion and Management 44:2763-2777. DOI: http://dx.doi.org/10.1016/S0196-8904(03)00025-6 http://dx.doi.org/10.1016/S0196-8904(03)... )	2 (Altafini et al., 2003Altafini CR, Wander PR, Barreto RM (2003) Prediction of the working parameters of a wood waste gasifier through an equilibrium model. Energy Conversion and Management 44:2763-2777. DOI: http://dx.doi.org/10.1016/S0196-8904(03)00025-6 http://dx.doi.org/10.1016/S0196-8904(03)... )	3 (Jarungthammachote & Dutta, 2007Jarungthammachote S, Dutta A (2007) Thermodynamic equilibrium model and second law analysis of a downdraft waste gasifier. Energy 32:1660-1669. DOI: http://dx.doi.org/10.1016/j.energy.2007.01.010 http://dx.doi.org/10.1016/j.energy.2007.... )^* * CH4 amount fixed to the average experimental value obtained by Jarungthammachote & Dutta (2007).	4 (Fournel et al., 2015Fournel S, Marcos B, Godbout S, Heitz M (2015) Predicting gaseous emissions from small-scale combustion of agricultural biomass fuels. Bioresource Technology 179:165-172. DOI: http://dx.doi.org/10.1016/j.biortech.2014.11.100 http://dx.doi.org/10.1016/j.biortech.201... )^* * CH4 amount fixed to the average experimental value obtained by Jarungthammachote & Dutta (2007).	5 This study (No C(s) formed)	6 This study (No C(s) formed)^* * CH4 amount fixed to the average experimental value obtained by Jarungthammachote & Dutta (2007).	7 This study (With C(s) formation)	8 This study (With C(s) formation)^* * CH4 amount fixed to the average experimental value obtained by Jarungthammachote & Dutta (2007).
CH₄	2.31	0	1.66	1.66	0.03	1.66	0.01	1.66
CO	20.14	19.7	23.34	21.47	27.11	25.32	21.16	20.16
CO₂	12.06	10.15	9.82	11.14	7.43	8.87	11.5	12.56
H₂	14.00	20.06	18.24	18.83	22.8	19.93	21.05	18.39
N₂	50.79	50.1	46.93	46.9	42.63	44.21	46.28	47.23
RMSE	-	3.05	3.12	2.88	6.62	5.46	3.92	2.55

Correlations	This study Eq. 2 and 13	This study Eq. 2 and 13 ^* * Model with CH4 amount fixed to the average experimental value obtained by Jarungthammachote & Dutta (2007).
0.054 (Eq. 15)	0.0477	0.040
0.821 (Eq. 16)	0.855	0.881

Associação Brasileira de Engenharia Agrícola SBEA - Associação Brasileira de Engenharia Agrícola, Departamento de Engenharia e Ciências Exatas FCAV/UNESP, Prof. Paulo Donato Castellane, km 5, 14884.900 | Jaboticabal - SP, Tel./Fax: +55 16 3209 7619 - Jaboticabal - SP - Brazil
E-mail: revistasbea@sbea.org.br

Acompanhe os números deste periódico no seu leitor de RSS

[1] *Corresponding author. Universidade Federal de Minas Gerais/ Belo Horizonte - MG, Brasil. E-mail: viniciusramos92@gmail.com