Coal Swelling Model for Pressurized High Particle Heating Rate Pyrolysis Applications

Abstract

A model was previously developed to describe the decrease in swelling during coal pyrolysis at atmospheric pressure when maximum particle heating rates increase from 104 K/s to 105 K/s. That model included effects of coal type using chemical structure properties. This paper presents results of new experiments to study the effects of elevated pressure and high heating rates on coal pyrolysis. A pressurized flat-flame burner (PFFB) was designed and built to conduct these studies. The pyrolysis experiments reported in this paper were conducted at particle heating rates of ∼105 K/s and maximum gas temperatures of 1700 to 1900 K at pressures of 1 to 15 atm. Residence times of 25–85 ms were used. A new coal swelling correlation was developed that predicts the effects of heating rate, pressure, and coal rank on the swelling ratio at heating rates above ∼104 K/s. The coal rank index parameters from a previously published atmospheric swelling model were used to model the pressurized swelling data, and a new correl...