Modeling Framework for Biogenic Methane Formation from Coal

Abstract

In situ biodegradation of coal to methane offers an innovative and attractive alternative to the prevailing methods of harnessing the energy potential of coal. This alternative approach employs a community of microorganisms to biologically generate methane from unmined coal and has the promise of causing less pollution, reducing the environmental impact of mining, and being potentially less expensive. 9,10,15−18 The goal of our work is to develop a novel, comprehensive, and quantitative mathematical modeling framework to better understand the process of biogenic methane formation from coal. Intermediate chemical species and metabolic pathways are identified using existing literature information and are incorporated into a lumped kinetic model, referred to as the Coal to Methane (C2M) Kinetic Model. Several intermediate compounds have been lumped into polyaromatics (PACs), long chain fatty acids (LCFAs), and mid chain fatty acids (MCFAs), etc. The simulations of the model and sensitivity analysis along with a metabolic pathway connectivity map are useful for guiding experimental design and establishing important intermediate metabolites and bottlenecks. The dependence of methane production on temperature and concentration of enzymes has been studied through sensitivity analysis of kinetic parameters, showing CO 2 reduction and acetate cleavage play a significant role. Additionally, interdependence of MCFA hydrolysis to acetate and conversion of acetate to methane has been identified, implying acetate regulation as a key factor of methane formation. The mathematical model compares favorably to a limited set of experimental data provided by ArcTech Inc. Model parameters can aid in understanding the impact of metabolic bottlenecks on the bioconversion process and can be useful for monitoring or controlling the biogenic methane process.

Importance of specific substrate utilization by microbes in microbially enhanced coal-bed methane production: A modelling study

“…Experimental studies focusing on MECBM, performed at Montana State University (MSU) [3,5,6], provide the basis for modelling MECBM production with two-phase multi-component transport processes using the numerical simulator DuMu X [7]. Numerical modelling has proven to be a valuable tool for testing hypotheses developed from observations and experimental studies and for designing beneficial experiments [8? ], yet only few models describing microbial activity in coal-beds are found in the literature ( [9], [10]).…”