- Users Manual for latest CPD model, including the nitrogen release model and the model to calculate the species concentrations in the light gases (PDF file)
We have been working on measurements and modeling of the nitrogen evolution during coal devolatilization in order to remove some of the empiricism in current models. Measurements to date have focused on a combination of 13-C NMR and elemental analysis of solid (char) and condensed phase (tar) products, along with analysis of gas phase species using FTIR. Recent developments include a method to determine the mass of nitrogen per aromatic mass (referred to as Nsite) from the solid-state 13-C NMR data and the elemental analysis. This provides a set of data on the chemical structure of nitogen in the char and tar. Models that are capable of matching the gas phase species as well as the nitrogen transformations in the char and tar must match some of the chemistry involved, and hence are less empirical than previous models. Such a model has recently been developed by Steve Perry in his PhD dissertation, and is available (see below). The most recent work was done on secondary reactions of nirtogen species (tar going to HCN and NH3) by Haifeng Zhang. References are provided below.
Perry, S., E. M. Hambly, T. H. Fletcher, M. S. Solum, and R. J. Pugmire, " Solid-State 13C NMR Characterization of Matched Tars and Chars From Rapid Coal Devolatilization," Proceedings of the Combustion Institute, 28, 2313-2319 (2000).
Perry, S., T. H. Fletcher, R. J. Pugmire, M. S. Solum, "A Global Free-Radical Mechanism for Light Gas Nitrogen Release from Coal during Devolatilization," Energy & Fuels, 14, 1094-1102 (2000). (PDF file from E&F)
Perry, S., "A Global Free-Radical Mechanism for Nitrogen Release During Devolatilization Based on Coal Chemical Structure," Ph.D.disertation in Chemical Engineering, Brigham Young University (1999)(PDF Document - 1 MB)
Zhang, H., "Nitrogen Evolution and Soot Formation during Secondary Coal Pyrolysis," Ph.D. in Chemical Engineering, Brigham Young University (April, 2001) (pdf file, 812 K)
Zhang, H. and T. H. Fletcher, "Nitrogen Transformations furing Secondary Coal Pyrolysis," Energy & Fuels, 15, 1512-1522 (2001). (PDF file from E&F)
Chemical Percolation Devolatilization (CPD) Nitrogen and Light Gas (NLG) Model
A modified verion of the CPD model
has been completed that calculates nitrogen release in the tar and light gas,
and also the amount of nitrogen remaining in the char. This model was initially
developed by Dominic Genetti (MS, BYU, 1999), and later modified substantially
by Steve Perry (PhD, 2000). In addition, this model uses a correlation to calculate
the mass fraction of major light gas species in the light gas fraction as a
function of time, using a table look-up procedure. Thus, the computational eficiency
of the CPD model is maintained, and the number of ODE's solved in the code is
minimized.
- Users Manual for latest CPD model, including the nitrogen release model and
the model to calculate the species concentrations in the light gases (PDF
file)
- Files for new CPD model, including
nitrogen release and gas species (Directory of Files)
This version includes use of a user-specified
particle temperature profile.
- Files for new CPDCP model, including
nitrogen release and gas species (Directory of Files)
This version includes solution of
the particle energy equation based on a gas temperature profile.
- Dominic Genetti's M.S. Thesis,
BYU, 1999, "An Advanced Model of Coal Devolatilization Based on Chemical Structure,"
(PDF file - 720K)
- Steve Perry's Ph.D. Dissertation,
BYU, 2000, "A Global Free-Radical Mechanism for Nitrogen Release During Devolatilization
Based on Coal Chemical Structure," (PDF file
- 1 MB)
I am trying to generate a user database for the CPD model. If you would like free updates on improvements to the CPD model and related correlations, please send me an email: tom_fletcher@byu.edu.