Modelling of a solid oxide fuel cell for integrated coal gasification hybrid power plant simulation

Abstract

Now and in the mid-term future, coal remains an important energy source for electricity generation for reasons of energy supply security and economics. The expectation for low CO2-emissions and high plant efficiencies make solid oxide fuel cells an essential part of numerous innovative power plant concepts. For that reason, simplified and flexible models for solid oxide fuel cells are needed, which can be implemented easily in complex power plant system simulations. A model for a tubular solid oxide fuel cell based on a semi-empirical approach has been developed. The created model is successfully validated with operating data of demonstration plants published in literature. A parametric study for the target application in a hybrid power plant with high temperature fuel cells of fuel gas composition, operating pressure and temperature, fuel utilization and electrical power density is presented. By means of these, the model of the fuel cell is qualified for implementation in hybrid power plants system models. Additionally, characteristic diagrams obtained by variation of the operating pressure and the fuel utilization are discussed. With the help of the diagrams, the electric and energetic performance of the SOFC over a wide range of these parameters is described by isolines for discrete values of the electrical efficiency and voltage of the fuel cell.

Keywords

• modelling; SOFC; tubular cell; coal gasification; IGFC; hybrid power plant

References

1. = 0.167) (A.14) Δ ∗= {10 bar +
2. 15 bar − 10 bar : 1 bar < ≤ 3 bar
3. 3 bar+5 bar − 3 bar( − 3 bar) − 1 bar: 3 bar < ≤ 5 bar
4. 5 bar+10 bar − 5 bar( − 5 bar) − 1 bar 10 bar− 5 bar( − 5 bar) −
5. : 5 bar < ≤ 10 bar 1 bar : > 10 bar with
6. 1 bar= −6.164 ∙ 10−9( V
7. 3 bar= −2.820 ∙ 10−9( V
8. 5 bar= −3.113 ∙ 10−9( V

9. 10 bar= −2.082 ∙ 10−9( V 2 2 A/m² ) + 0.8110 A/m² )− 3.989 ∙ 10−5( A/m² 2 A/m² )− 3.892 ∙ 10−5( A/m² ) + 0.8751 A/m² )− 4.295 ∙ 10−5( 2 2
10. 15 bar= −2.737 ∙ 10−9( V A/m²
11. )− 034 ∙ 10−5( A/m² ) + 0.9059 ∆ ℎ ( , = 0.167) = 4 [ln( ̅̅̅̅) 2 − ln (( ̅̅̅̅) 2 =0.167 )]
12. p = operating pressure [bar] ( ̅̅̅̅) 2 =0.167
13. mole fraction at the inlet and outlet of the stack Δ = Δ ∗+ Δ
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