Investigation of pulverized coal combustors and gasifiers: multiple sub-reactor model and experimental results

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1982

OSTI ID:6255783

George, II, P E

A continuous stirred tank reactor model is developed for combustion and gasification of pulverized coal or hydrocarbon fuels. Elementary gas phase reactions are used for wet carbon monoxide and methane combustion. Global reaction mechanisms are used for hydrocarbons other than methane. Coal mass loss due to pyrolysis is modeled using a competing reaction method. Realistic combustion characteristics are ascribed to the pyrolysis products by approximating their composition. A shrinking core model is used for char reactions with oxygen, water vapor and carbon dioxide. A unique method is developed for determining the particle size distribution in the reactor. Char particles are assumed to enter at constant size, but variations in residence time produce a distribution of particle sizes in the reactor. Using a power law approximation for variation of the effective carbon rate coefficient with particle radius, the particle size distribution may be determined by integrating over the allowed residence times in the reactor. This method compensates for the change of effective carbon radius with increased residence time and provides accurate prediction for a very wide range of throughput. Conditions from equilibrium to blowout may be predicted over a range of equivalence ratios from 0.5 to 10.0. The CSTR coal model is used as a building block for multiple subreactor modeling of pulverized coal combustors and gasifers. Model predictions are compared to exhaust data from small scale cyclone and jet reactors investigated in this work and to internal data from a large experimental furnace at Ijmuiden, Holland. In addition to providing data for model comparison, the experimental results show that both the cyclone and swirled jet reactors may be used for low calorific value coal gasification.

• OSTI ID: 6255783
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010404* -- Coal
Lignite
& Peat-- Gasification
014000 -- Coal
Lignite
& Peat-- Combustion
42 ENGINEERING
421000 -- Engineering-- Combustion Systems
CARBONACEOUS MATERIALS
CHARS
CHEMICAL REACTIONS
CHEMICAL REACTORS
COAL
COAL GASIFICATION
COMBUSTION
COMBUSTORS
COMMINUTION
ENERGY SOURCES
FOSSIL FUELS
FUELS
FUNCTIONAL MODELS
GASIFICATION
MATERIALS
OXIDATION
PARTICLE SIZE
PULVERIZERS
PYROLYSIS PRODUCTS
SIZE
THERMOCHEMICAL PROCESSES
USES