Combined heat and power plants integrated with carbon capture: Process and system level potential
Typ
Examensarbete för masterexamen
Program
Sustainable energy systems (MPSES), MSc
Publicerad
2020
Författare
Ahlmén, Madeleine
Hellsberg, Jesper
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
The world has expressed a strong desire to mitigate climate change during the past decades. In Sweden, the government has expressed the aims to achieve negative carbon
emissions, Carbon Capture and Storage (CCS) is one of the key technologies in
reaching this goal. This thesis determines the national potential for carbon capture in
the Swedish waste and biomass fired Combined Heat and Power (CHP) plants. The
effects on plant performance and the operation of connected district heating systems
are evaluated.
The evaluation was performed by developing CHP plant process models of all 110
Swedish CHP plants based on plant data. Each model was retrofitted with postcombustion
carbon capture units with a 90 % capture rate of plant carbon dioxide
emissions. A district heating system dispatch model was created and incorporated
with the process models. The operating profiles of each plant was estimated based on
the heat demand within each district heating network. Four strategies for operating
the CHP plants were evaluated, based on the fuel consumption, district heating delivery
and electricity generation relative to the amount of carbon captured.
The results of the evaluation showed that the Swedish CHP plants alone have the
potential, if equipped with CCS, of reaching Sweden’s goal of 11 Mton negative emissions.
The Power to Heat Ratio ( ) (before implementation with CCS) is the most
determining factor for the CHP process performance after CCS integration. The most
determining factor for the district heating network performance is the ratio between
plant heat generation capacity and the peak demand for district heating. Each operational
strategy investigated, had advantages and disadvantages. The fuel consumption
will increase with the implementation of CCS regardless of the operating strategy, although
to different extents. Also, most CHP plants will not be able to maintain the
present heat delivery if integrated with CCS. Each district heating system is, however,
unique and should be investigated in further detail.
Beskrivning
Ämne/nyckelord
CCS , CHP , district heating , biomass , waste