The shale gas is an unconventional supplementary energy to traditional fossil energy

and is stored in layered rocks with low permeability and porosity

which leads to the difficulty for exploration of shale gas. Therefore

using CO

2

gas to displace shale gas has become an important topic. In this work

we use molecular simulations to study the displacement of shale gas by flue gas rather than CO

2

in which flue gas is modeled as a binary mixture of CO

2

and N

2

and the shale model is represented by inorganic Illite and organic methylnaphthalene. CH

4

is used as a shale gas model. Compared to the pure CO

2

flue gas is easily available and the cost of displacement by flue gas would become lower. Results indicate that the pore size of shale is an important factor in the process of displacing shale gas and simultaneously sequestrating flue gas

while the flue gas N

2

-CO

2

ratio shows a small effect on the process of CH

4

displacement

because the high partial pressure of flue gas is the main driving force for displacement of shale gas. Moreover

the geological condition also has a significant effect on the

process of CH

4

displacement by flue gas. Therefore

we suggest that the burial depth of 1 km is suitable operation condition for shale gas displacement. It is expected that this work provides a useful guidance for exploitation of shale gas and sequestration of greenhouse gas.