The system produces substantially pure CO2 at pipeline pressure for sequestration.
A power generation system has been proposed by British researcher Rodney Allam that claims to efficiently sequester CO2 and separate other pollutants. Termed as NET Power, the technology is capable of utilizing natural gas, coal, or biomass and does not need water to operate.
The invention provides methods and system for power generation using a high efficiency combustor (e.g., a transpiration cooled combustor) in combination with a circulating fluid (e.g., a C02 circulating fluid). The circulating fluid can be introduced into the combustor along with a fuel and an oxidant for combustion such that a high pressure, high temperature fluid stream is produced comprising the circulating fluid and combustion products. The fluid stream can be introduced into a turbine.
The fluid stream can be maintained at a relatively high pressure during expansion in the turbine such that the pressure ratio across the turbine (i.e., the ratio of the pressure at the turbine inlet and the pressure at the turbine outlet) is less than about 12. The fluid stream can then be further processed for separation of the components of the fluid stream, which can include passing the fluid stream through a heat exchanger.
The circulating fluid (at least a portion of which may be recycled from the fluid stream) can be passed through the same heat exchanger to heat the circulating fluid prior to introduction into the combustor. The heat exchanger is operated through selection of a low grade heat source so that only a small temperature difference exists between the turbine exhaust and the recycle fluid at the hot end of the heat exchanger.
The system can produce substantially pure CO2 at pipeline pressure for sequestration. The CO2 also may be recycled into the power production system.
A wide variety of fuel sources can be used. For example, the high efficiency combustor used according to the invention can make use of gaseous (e.g., natural gas or coal derived gases), liquid (e.g., hydrocarbons, bitumen) and solid (e.g., coal, lignite, pet-coke) fuels.