Modelling of flue gas injection and collaborative optimization of multi-injection parameters for efficient coal-based carbon sequestration combined with BP neural network parallel genetic algorithms

•A refined THMC model with a convenient permeability model for GM-ECBM is established.•Different views on elevated injection temperature are explained for the first time.•Cooperative equalization can achieve a win–win situation of ECBM and CCS.•An objective function with multiple categories of costs...

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Bibliographic Details
Published in:Fuel (Guildford) Vol. 368; p. 131536
Main Authors: Fan, Zhanglei, Fan, Gangwei, Zhang, Dongsheng, Zhang, Lei, Chai, Yujian, Yu, Wei
Format: Journal Article
Language:English
Published: Elsevier Ltd 15.07.2024
Subjects:
Cooperative equalization
GA-BP neural network
Objective function
Permeability model
THMC model
THMC model
Permeability model
GA-BP neural network
Objective function
Cooperative equalization
ISSN:0016-2361
Online Access:Get full text
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Summary:•A refined THMC model with a convenient permeability model for GM-ECBM is established.•Different views on elevated injection temperature are explained for the first time.•Cooperative equalization can achieve a win–win situation of ECBM and CCS.•An objective function with multiple categories of costs and revenues is developed.•CO2 adsorption-induced capacity determines optimal CO2 proportion and optimizability. Cooperative equalization among the injection parameters can control the economic objective function to ensure the efficiency of gas-mixture-enhanced coalbed methane recovery (GM-ECBM). This study first proposed and validated a refined thermal-hydro-mechanical-chemical (THMC) coupling model with a convenient permeability model. Based on GM-ECBM numerical calculation results under different combinations of injection parameters, different types of cost-income objective functions, including different costs and incomes, were optimized by parallelly applying a genetic algorithm and backpropagation neural network (GA-BP). Using the recovery rate as the index, a small inter-well distance and a large injection pressure can increase the optimal CO2 proportion. The effectiveness of enhancing the injection temperature was significantly correlated with both inter-well distance and the injection pressure. Cooperative equalization among the injection parameters can explain different viewpoints of different scholars on the temperature effect. Large Henry’s law constants resulted in low carbon sequestration and coalbed methane (CH4) production but did not affect the optimal CO2 proportion. High carbon sequestration and CH4 prices corresponded to small inter-well distances and large injection pressure. Based on the objective function, the optimal inter-well distance and the injection temperature were 175–220 m and 305.5–311.5 K, respectively. The volumetric adsorption-induced expansion coefficient (VAEC) of CO2 determined the optimal CO2 proportion, the optimization feasibility of the injection scheme, and the applicability of GM-ECBM.
ISSN:0016-2361
DOI:10.1016/j.fuel.2024.131536