Calculations for OPF with Adjustable Tap Ratios

In this document, the calculations of the AC power balance and flow equations used by MATPOWER will be extended to include adjustable tap ratios

Gasification of coal-derived chars in synthesis gas mixtures under intraparticle mass-transfer-controlled conditions

A model has been formulated to describe the quasi-steady-state gasification of coal-derived chars in gas mixtures where both the reactants carbon dioxide and steam, and the gasification products carbon monoxide and hydrogen are present. As such, these conditions reflect the situation found in most practical gasification systems.\ud \ud The model presented is applied under conditions where intraparticle mass transfer is rate-controlling. Intraparticle heat transfer is neglected. In view of the non-equimolar gasification reactions, the mass flux equations are derived from the continuum limit of the dusty gas model. These flux equations are combined with strongly non-linear Langmuir-Hinshelwood kinetics for the gasification reactions. The model accounts for local variations of the diffusive and convective permeability parameters, as well as variations in the reactive surface area, during burnoff of a char particle.\ud \ud The impact of the various relevant mass-transfer parameters, the gasification temperature and pressure, and the char particle size on the gasification behaviour is discussed. A comparison is made between the present model and existing models, and various modelling approaches are critically reviewed

Effects of intraparticle heat and mass transfer during devolatilization of a single coal particle

The objective of the present work is to elucidate the influence of intraparticle mass and heat transfer phenomena on the overall rate and product yields during devolatilization of a single coal particle in an inert atmosphere. To this end a mathematical model has been formulated which covers transient devolatilization kinetics and intraparticle mass and heat transport. Secondary deposition reactions of tarry volatiles also are included. These specific features of the model allow a quantitative assessment to be made of the impact of major process conditions such as the coal particle size, the ambient pressure and the heating rate on the tar, gas and total volatile yield during devolatilization. Model predictions are compared to a limited number of experimental results, both from the present work and from various literature sources