Evaluation of an Absorption Based aMDEA Process Using Aspen Plus: A conceptual study of biobased carbon capture technology for a combined heat and power plant
Typ
Examensarbete för masterexamen
Program
Sustainable energy systems (MPSES), MSc
Publicerad
2022
Författare
Larsson, Jesper
Larsson, Tove
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Production of heat and power through combustion of fossil fuels has contributed
with increased levels of CO2 in the atmosphere, causing climate change and environmental
problems. A solution to contribute to a sustainable energy system and
mitigate CO2 emissions, is to combine biomass gasification with carbon capture technology.
This thesis aims to investigate a hydrogen production unit for a combined
heat and power plant, which includes chemical absorption based carbon capture.
The solvent used is an aqueous solution of N-Methyldiethanolamine (MDEA) and
piperazine (PZ).
Models for the hydrogen production process were constructed in the simulation
software Aspen Plus. The carbon capture model was investigated in a parameter
study where important process parameters were identified. Liquid-to-gas ratio, solvent
composition, pressures levels in the absorption and desorption columns, and
feed temperatures into the respective columns were investigated. An optimization
with the objective of minimizing the heat demand in the process was also included
in the model evaluation.
Liquid-to-gas ratio was found to have a large impact on the absorption efficiency,
with increased absorption as a result of increased liquid-to-gas ratio. It was found
that an optimum ratio could be located, where excess heating of the process was kept
to a minimum. Investigation of solvent composition showed that the ratio between
MDEA and PZ was a key design parameter, in terms of carbon capture efficiency
and energy demand of the process. An increase in capture rate as a result of increased
pressure in the absorber was recognized, as a cause of increased solubility of
CO2 at higher pressures. Increased pressure in the stripper column was identified
as a parameter favorable for increased heat integration of the system.
Beskrivning
Ämne/nyckelord
Aspen Plus , Carbon capture , Chemical absorption , MDEA , PZ