High-pressure entrained flow coal gasification is becoming increasingly important particularly in the development of Integrated Coal Gasification Combined Cycle (IGCC) technology for the production of electricity. However, there is a lack of knowledge worldwide for the gasification process and more especially for the chemical reactions (reactions rates, constants) that take place under high pressure and temperature. Therefore a gasifier has been designed and is being built at the Institute for Energy Systems (Lehrstuhl für Energisysteme -LES) at the Technische Universität München (TUM). This gasifier is an entrained flow gasifier and has the advantage that it can operate to very high conditions of pressure and temperature, up to 50 bar pressure and 1800 textdegreeC temperature. In an ongoing project, a great variety of experiments under different conditions are planned to determine chemical reactions rates at high pressure conditions. In addition to the experimental work, CFD numerical simulations of pulverized coal gasification are being performed. The aim is to use numerical investigations for preliminary assessment of the facility. The goal is to develop a gasification model suitable for high pressure and condition tailored on the experiments to be used in CFD computations to predict chemical products, the heat transfer and the turbulence inside the gasifier. To this purpose the Watanabe- Otaka model has been chosen as a reference set of reactions and reaction rates. This coal gasification model was developed for 20 bar pressure and 1400 textdegreeC temperature. To better adapt this model to the LES gasifier working conditions, the 50 bar pyrolysis model developed by Yang was implemented. The Yang?s model predicts devolatilization at high pressure and temperature conditions. To test the compatibility of the modified coal gasification with the LES experiments, the gasifier geometry from Watanabe-Otaka and the geometry of the LES gasifier were selected for the CFD simulations carried on at the designed operating conditions of the LES gasifier. The pressure range was 1-50 bar and the temperature range was 1200-1800 textdegreeC. Numerical results show the influence of the pressure both on the devolatilization process and on the hydrogen?s production. Although these results seem to be overestimated compared to the expected, as there is a significant difference between the pressure levels used for the pyrolysis and the gasification for the reactions. Future work is oriented to develop a model suitable for the LES gasifier operating conditions and to validate numerical results against experimental data.
«
High-pressure entrained flow coal gasification is becoming increasingly important particularly in the development of Integrated Coal Gasification Combined Cycle (IGCC) technology for the production of electricity. However, there is a lack of knowledge worldwide for the gasification process and more especially for the chemical reactions (reactions rates, constants) that take place under high pressure and temperature. Therefore a gasifier has been designed and is being built at the Institute for E...
»
Login
BibTeX