Abstract
This paper will discuss novel technologies for increasing the energy
efficiency of offshore oil and gas platforms. Three case studies are
in progress that are based on actual oil-producing platforms—two
on the Norwegian Continental Shelf (NCS) and one in the Brazilian
basin. The current focus is on developing compact, novel bottoming
cycles for recovery of waste heat from the gas turbine and heat recovery
from the compressor train for gas export. The technologies
under investigation use steam and alternative working fluids, such
as carbon dioxide (CO2) and hydrocarbons. All the fluids investigated
in this project are natural working fluids; hence, they will not
cause any unexpected environmental issues in the future.
A case study was performed that considered an 18-year period
of operation on an actual platform and a scenario in which one gas
turbine was removed and replaced with a CO2 bottoming cycle by
use of the exhaust heat from a different gas turbine. The beauty of
this scenario is that it would not increase the weight on the platform
because the crate containing the gas turbine to be removed
was of a weight similar to that of the crate containing the CO2 bottoming
cycle. The substitution would not affect the ability to cover
the heat demand on the platform because a waste-heat-recovery
unit (WHRU) could be installed on the platform’s other gas turbine.
The case study indicates a significant reduction in CO2 emissions
of 22% (63 000 t/a), and does not involve adding additional
weight or volume to the platform. If operating on the NCS, the annual
savings in reduced fuel costs and CO2 tax from implementing
this scenario would be USD 17 million, although much lower in
other territories.
efficiency of offshore oil and gas platforms. Three case studies are
in progress that are based on actual oil-producing platforms—two
on the Norwegian Continental Shelf (NCS) and one in the Brazilian
basin. The current focus is on developing compact, novel bottoming
cycles for recovery of waste heat from the gas turbine and heat recovery
from the compressor train for gas export. The technologies
under investigation use steam and alternative working fluids, such
as carbon dioxide (CO2) and hydrocarbons. All the fluids investigated
in this project are natural working fluids; hence, they will not
cause any unexpected environmental issues in the future.
A case study was performed that considered an 18-year period
of operation on an actual platform and a scenario in which one gas
turbine was removed and replaced with a CO2 bottoming cycle by
use of the exhaust heat from a different gas turbine. The beauty of
this scenario is that it would not increase the weight on the platform
because the crate containing the gas turbine to be removed
was of a weight similar to that of the crate containing the CO2 bottoming
cycle. The substitution would not affect the ability to cover
the heat demand on the platform because a waste-heat-recovery
unit (WHRU) could be installed on the platform’s other gas turbine.
The case study indicates a significant reduction in CO2 emissions
of 22% (63 000 t/a), and does not involve adding additional
weight or volume to the platform. If operating on the NCS, the annual
savings in reduced fuel costs and CO2 tax from implementing
this scenario would be USD 17 million, although much lower in
other territories.
