TITLE:
Simulation of a NGCC Power Generation Plant for the Production of Electricity from CO2 Emissions Part II: SNGCC Power Plant
AUTHORS:
Asfaw Gezae Daful, Zin Eddine Dadach
KEYWORDS:
Synthetic Natural Gas Combined Cycle (SNGCC)
JOURNAL NAME:
Journal of Power and Energy Engineering,
Vol.8 No.8,
August
25,
2020
ABSTRACT: The objective of the first part of the investigation was to use Aspen
Plus software and the Redlich-Kwong-Soave equation of state in order to
simulate an adiabatic methanation reactor for the production of synthetic
natural methane (SNG) using 1 kg/hr of
carbon dioxide. In this paper, we define the Synthetic Natural Gas Combined
Cycle (SNGCC) as a combined cycle power plant where the fuel is synthetic
natural gas (SNG) produced by a methanation reactor. The feed of the
methanation reactor is the recycled stream of carbon dioxide of a CO2 capture unit treating the flue gas of the SNGCC power plant. The objective of
the second part of the investigation is the utilization of Aspen plus software
with SRK equation of state for the simulation of the SNGCC power plant. The
metallurgical limitation of the gas turbine was fixed at 1300°C
in this investigation. For effective absorption by amine solutions, the molar
percentage of CO2 in the flue gas should be higher than
10%. Moreover, in order to reduce technical problems linked to oxidative
degradation of amine in the CO2 capture plant, the
percentage of O2 in the flue gas should also be lower
than 5%. To reach this goal, the primary air for combustion has 10% excess air
(compared to stoichiometric air) and 37% of the flue gas leaving the SNGCC is recirculated as the secondary air for cooling
the turbine. As a result, the concentration of CO2 and O2 of the
flue gas entering the CO2 capture unit were respectively
equal to 10.2% and 2.01%. The simulation results of the SNGCC power plant
indicate that 6.6 MJ of electricity are produced for each kg of carbon dioxide
recycled from the CO2 capture unit of the power plant.
In other terms, the production of the 24.88 kg/hr of
synthetic natural gas (SNG) consumes 62.36 kg/hr of
recycled carbon dioxide and 16.4 kg/hr of
hydrogen. The SNG produced by the methanation reactor of the power plant
generates 114 kW of electricity. It is assumed in this paper that the hydrogen
needed for the methanation of carbon dioxide is a product of a catalytic
reforming plant that produces gasoline from heavy naphta fraction of an
atmospheric distillation unit of crude oil.