The development of a computer model for a fixed bed gasifier and its use for optimization and control

Area of Science:

• Chemical Engineering
• Thermodynamics
• Reaction Kinetics

Background:

• Fixed-bed gasifiers are crucial for converting biomass and waste into syngas.
• Optimizing gasifier performance and control is essential for efficient energy production.
• Accurate mathematical models are needed to understand and improve gasifier operation.

Purpose of the Study:

• To develop and validate a mathematical model for a fixed-bed gasifier.
• To investigate the stationary performance of the gasifier using the model.
• To identify an efficient control strategy for gasifier operation during load changes.

Main Methods:

• Development of a one-dimensional model based on conservation of mass and energy.
• Incorporation of gas-phase chemical equilibrium and Langmuir-Hinshelwood kinetics for char reactions.
• Validation of the model against experimental data.
• Thermo-gravimetric analysis to determine beech char reactivity.

Main Results:

• The mathematical model accurately predicted gasifier performance.
• An efficient and simple control strategy for load changes was identified.
• The control strategy was successfully implemented in an automated power plant, operating for over 3000 hours.
• Beech char reactivity was characterized as a function of temperature, gas composition, and conversion.

Conclusions:

• The developed mathematical model is a valuable tool for analyzing and controlling fixed-bed gasifiers.
• The identified control strategy enhances operational efficiency and stability.
• The study demonstrates the successful application of modeling and experimental analysis in optimizing power plant operation.