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Energy Technology Centre in Piteå Modelling, Simulation and Optimisation of a Downflow Entrained-flow Reactor for Pressurised Black Liquor Gasification.

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Presentation on theme: "Energy Technology Centre in Piteå Modelling, Simulation and Optimisation of a Downflow Entrained-flow Reactor for Pressurised Black Liquor Gasification."— Presentation transcript:

1 Energy Technology Centre in Piteå Modelling, Simulation and Optimisation of a Downflow Entrained-flow Reactor for Pressurised Black Liquor Gasification Magnus Marklund, PhD student ETC

2 Energy Technology Centre in Piteå Gasification Plant Gasification Reactor  600 mm H: 1886 mm

3 Energy Technology Centre in Piteå Objective The main goal is to develop an advanced process model for the reactor that can be used for design optimisation of arbitrary unit sizes.

4 Energy Technology Centre in Piteå Main model specifics Based on a commercial CFD code Simplified atomiser/burner Submodels for drying, pyrolysis, and char gasification Gas/droplet interactive turbulence model Partial combustion of fuel gases Inclusion of radiation and conjugate heat transfer Submodel for thickness prediction of smelt layer on wall Inorganic (smelt) reactions

5 Energy Technology Centre in Piteå Methodology CFX4 (or FLUENT 6/CFX5) Distribution of non interacting discrete droplets Droplet conversion by customised user routines k-  and Reynolds stress turbulence models Gas combustion modelled by EDC Discrete transfer or Monte Carlo method for thermal radiation and a coupled model for conjugate heat transfer Åbo Academy’s model for wall layer thickness Inorganic (smelt) reactions by customised user routines

6 Energy Technology Centre in Piteå Plan 01/02 CFD4: Possible collaboration with Dr. Fletcher USYD or Åbo Academy EXP1: Possible founding of a Particle Dynamics Analysis (PDA) device

7 Energy Technology Centre in Piteå Modified coal combustion model Needed: Proximate analysis (Moisture, volatiles, fixed carbon, and ash) Ultimate analysis of the volatiles and fixed carbon Higher heating value Emissivities for droplet and char particle Devolatilization: Moisture and volatiles are released at a rate proportional (Arrhenius) to the remaining volatiles in the droplets Droplet swells linearly with released volatiles Char gasification: Only combustion with oxygen Controlled by diffusion of oxygen to the droplet surface and the char reactivity

8 Energy Technology Centre in Piteå Uncertainties and difficulties Uncertainties: Droplet size and velocity distributions from burner Parameters for devolatilization and gasification rates Characteristic volatile composition Gasification of char Boundary conditions for heat transfer Difficulties: Resolving the burner Convergence

9 Energy Technology Centre in Piteå Simulations So far... 2-dimensional axi-symmetric model Burner modelled as a circular inlet Simplified mechanistic model (no gas/ droplet interaction) CFX4 coal combustion model K-  turbulence model Eddy Dissipation Model (EDM) and Eddy Dissipation Concept (EDC) …to come 2D and 3D models More detailed burner (separate inlets for liquor and oxygen) Implementation of a more advanced droplet/gas interaction model Reynolds stress turbulence model Wall smelt layer

10 Energy Technology Centre in Piteå First results (simple model) 90º Full-cone95º Full-cone

11 Energy Technology Centre in Piteå Latest results (coal model) 110° full cone spray70° full cone spray

12 Energy Technology Centre in Piteå For updated information Acknowledged sponsors:


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