CCS and Power Systems
ADVANCED ENERGY SYSTEMS - GASIFICATION SYSTEMS
Conversion and Fouling
Performer: NETL Office of Research and Development
Project No: FWP-2012.03.03 Task 3
Accurate physical models are needed to predict the rates of slag buildup in a gasifier or ash deposition in a syngas convective cooler. Gasification plants can experience lower carbon conversion and plugging of syngas coolers with fly ash, reducing the thermal efficiency of a gasifier and its overall reliability. Molten ash chemistry and viscosity are crucial aspects of carbon feedstock ash impact on slag properties and refractory corrosion in a gasifier.
In this project researchers will develop reduced order models (ROMs) with higher fidelity computational fluid dynamics models coupled to the ROMs to enable more accurate prediction of gasifier performance. Proposed devolatization and char kinetics work will attempt to identify the factors responsible for the formation of fly ash particles by using the traditional mineral processing approach of particle partitioning and by superimposing kinetics of char and mineral transformations. Slag viscosity will be investigated using a high-temperature rotating-bob viscometer and a temperature gradient furnace in which slag infiltration in a controlled atmosphere can be studied. Particle deposition testing will initially be conducted at temperatures relevant to the convective syngas coolers in order to generate ash particle chemistry; ash adhesion probabilities as a function of particle size, temperature, and velocity; surface temperature; and contact angle. Ash particles from the High Pressure Entrained Flow Reactor (HPEFR) at Pennsylvania State University (Penn State) will be generated from coal and petcoke feedstocks that are separated into multiple size and density fractions, each containing various amounts of mineral matter, which will be used to determine the characteristics of the fly ash particles. The effect of iron sulfides and other coatings on particle deposition will also be investigated in the latter stages of the project, and a comprehensive model for ash deposition at convective syngas cooler (CSC) conditions will be generated.
|Particle deposition experimental schematic