Modelling gas cooling in Black Liquor Gasification

Lars Johansson (1) , Lars Westerlund (1)

1 Division of Energy Engineering

Pressurized Entrained Flow High Temperature Black Liquor Gasification (PEHT-BLG) is a new technology not yet commercialized. The technology has the potential to improve the efficiency of energy and chemical recovery in the pulping industry. It also enables new processes, i.e. production of renewable motor-fuels from the syngas. The technology is not yet fully developed and interest in computer models for scale-up and optimization of the process in combination with experiments is favourable in the development process. A demonstration plant has been in operation since late 2005, in Pitea, Sweden. At Lulea University of Technology (LTU), a CFD model of a vertical tube in the counter current condenser has been developed using the commercial code FLUENT 6. The geometry is consistent with the demonstration plant and input data of the design has been used as boundary conditions for the model. The objective is to create a CFD model that can be used as a designing tool for the technology developer in future scale-up and for commercialized units. The model predicts the condensation process very well and shows that the major part of the condensation takes place in the first quarter of the tube under the given conditions. The heat transfer through the tube wall has been modelled based on results from the literature. The results show the importance of accurate heat transfer coefficients. Compared to designing data, the heat transfer through the wall and the condensate rate show good agreement. However, these results need to be validated against experimental data for different conditions.

Mots clés: Condensation; Simulation; CFD; saturated

Domaines: Thermique [physics.class-ph]; Thermique [physics.class-ph]

Lars Johansson, Lars Westerlund. Modelling gas cooling in Black Liquor Gasification. Applied Thermal Engineering, 2011, 31 (16), pp.3176. ⟨10.1016/j.applthermaleng.2011.05.043⟩. ⟨hal-00789887⟩