Direct fired power cycle

A method for implementing a thermodynamic cycle comprising the steps of:

• superheating a gaseous working stream;
• expanding the superheated gaseous working stream to transform its energy into usable form;
• dividing the expanded gaseous working stream into a withdrawal stream and a spent stream;
• reheating the spent stream and expanding the reheated spent stream;
• cooling the withdrawal stream and the spent stream, after the expansion of the spent stream, the cooling of the withdrawal stream and the spent stream transferring heat used to superheat the gaseous working stream;
• combining the withdrawal stream with a lean stream, having a higher content of a high-boiling component than the withdrawal stream, to form a composite stream that condenses over a temperature range that is higher than the temperature range required to evaporate an oncoming liquid working stream;
• condensing the composite stream to provide heat to evaporate the oncoming liquid working stream, the evaporation of the liquid working stream transforming the liquid working stream into the gaseous working stream, and to provide heat to the lean stream;
• cooling and condensing the composite stream to preheat the liquid working stream;
• expanding the composite stream to reduce the pressure of the composite stream;
• partially evaporating a first portion of the expanded composite stream with heat transferred from a counterstream of the same composite stream, that has not yet been expanded, and with heat transferred from said spent stream;
• separating the partially evaporated composite stream to form a liquid stream, that produces the lean stream, and a vapor stream;
• combining the vapor stream with a second portion of the expanded composite stream to form a pre-condensed working stream, and condensing that pre-condensed working stream to produce the liquid working stream;
• pumping the lean stream to a higher pressure than the pressure of the liquid stream produced from the separation of the partially evaporated composite stream;
• heating the high pressure lean stream with a counterstream of the composite stream formed by combining the lean stream with the withdrawal stream;
• pumping the liquid working stream, formed from the condensation of said pre-condensed working stream, to a higher pressure, forming a high pressure liquid working stream;
• preheating the high pressure liquid working stream with heat transferred from counterstreams of the composite stream and the spent stream;
• and
• evaporating the preheated high pressure liquid working stream with heat transferred from the composite stream, producing the gaseous working stream.

A method for implementing a thermodynamic cycle comprising the steps of:

• superheating a gaseous working stream;
• expanding the superheated gaseous working stream to transform its energy into usable form;
• dividing the expanded gaseous working stream into a withdrawal stream and a spent stream;
• reheating the spent stream and expanding the reheated spent stream;
• cooling the withdrawal stream and the spent stream, after the expansion of the spent stream, the cooling of the withdrawal stream and the spent stream transferring heat used to superheat the gaseous working stream;
• combining the withdrawal stream with a lean stream, having a higher content of a high-boiling component than the withdrawal stream, to form a composite stream that condenses over a temperature range that is higher than the temperature range required to evaporate an oncoming liquid working stream;
• condensing the composite stream to provide heat to evaporate the oncoming liquid working stream, the evaporation of the liquid working stream transforming the liquid working stream into said gaseous working stream;
• cooling and condensing the composite stream to heat the lean stream and to preheat the liquid working stream;
• preheating and partially evaporating the liquid working stream with heat from the spent stream, after heat from the spent stream has been used to superheat the gaseous working stream;
• expanding the composite stream to reduce the pressure of the composite stream;
• partially evaporating a first portion of the expanded composite stream with heat transferred from a counterstream of the same composite stream, that has not yet been expanded, and with heat transferred from said spent stream;
• separating the partially evaporated composite stream in a separator to form a first liquid stream, that produces a portion of the lean stream, and a first vapor stream;
• combining the first vapor stream with a second portion of the expanded composite stream in a scrubber, second liquid and second vapor streams flowing from said scrubber;
• combining said first liquid stream flowing from said separator with said second liquid stream flowing from said scrubber to form said lean stream;
• pumping the lean stream to a higher pressure than the pressure of the first liquid stream that is produced from the separation of the partially evaporated composite stream;
• combining the second vapor stream flowing from said scrubber with a third portion of the composite stream, after the composite stream has been expanded, to form a pre-condensed stream, and condensing the pre-condensed stream to produce the liquid working stream;
• heating the lean stream, after pumped to a higher pressure, with heat from a counterstream of the composite stream that is formed by combining the lean stream with the withdrawal stream;
• pumping the liquid working stream, formed by the condensation of the pre-condensed working stream, to a higher pressure;
• preheating the liquid working stream, after pumped to a higher pressure, with heat transferred from counterstreams of the composite and spent streams;
• and
• evaporating the preheated liquid working stream with heat transferred from the composite and spent streams, producing said gaseous working stream.

Apparatus for implementing a thermodynamic cycle comprising:

• means for expanding a gaseous working stream to transform its energy into usable form;
• means for removing from said expanded gaseous working stream a withdrawal stream;
• a first stream mixer for combining the withdrawal stream with a lean stream, having a higher content of a high-boiling component than is contained in the withdrawal stream, to form a composite stream that condenses over a temperature range that is higher than the temperature range required to evaporate an oncoming liquid working stream;
• a heat exchanger for condensing the composite stream to provide heat to evaporate the oncoming liquid working stream to form the gaseous working stream;
• a gravity separator for separating the composite stream to form a liquid stream, a portion of which forms the lean stream, and a vapor stream;
• and
• a condenser for forming the liquid working stream that is evaporated by the composite stream in the heat exchanger.

Apparatus for implementing a thermodynamic cycle comprising:

• a heater for superheating a gaseous working stream;
• means for expanding the superheated gaseous working stream to transform its energy into usable form;
• a first stream separator for dividing the expanded gaseous working stream into a withdrawal stream and a spent stream;
• a reheater for reheating the spent stream and means for expanding the reheated spent stream after reheating;
• first and second heat exchangers for cooling the withdrawal stream and the spent stream, after the expansion of the spent stream, the cooling of the withdrawal stream and the spent stream transferring heat used to superheat the gaseous working stream;
• a first stream mixer for combining the withdrawal stream with a lean stream, having a higher content of a high-boiling component than the withdrawal stream, to form a composite stream that condenses over a temperature range that is higher than the temperature range required to evaporate an oncoming liquid working stream;
• a third heat exchanger for condensing the composite stream to provide heat to partially evaporate the oncoming liquid working stream, transforming the liquid working stream into a gaseous working stream;
• means for expanding the composite stream to reduce the pressure of the composite stream;
• a fourth heat exchanger for partially evaporating a first portion of the expanded composite stream with the heat transferred from a counterstream of the same composite stream, that has not yet been expanded, and a fifth heat exchanger for partially evaporating this portion of the expanded composite stream with heat transferred from said spent stream;
• a gravity separator for separating the partially evaporated first portion of the composite stream to form a first liquid stream, that forms a portion of the lean stream, and a first vapor stream;
• a scrubber for combining the first vapor stream with a second portion of said expanded composite stream, and for enabling second vapor and second liquid streams to flow from said scrubber;
• a second stream mixer for combining said first liquid stream and said second liquid stream to form said lean stream;
• a first pump for pumping the lean stream to a higher pressure than the pressure of the first liquid stream that is produced from the separation of the partially evaporated first portion of the composite stream;
• a third stream mixer for combining a third portion of the expanded composite stream with the second vapor stream, forming a pre-condensed working stream;
• a condenser for condensing the pre-condensed working stream to produce the liquid working stream;
• and
• a second pump for pumping the liquid working stream, after it flows from the condenser, to a pressure that is higher than the pressure of the liquid working stream after it flows from the condenser, said high pressure liquid working stream evaporated in said third heat exchanger to produce said gaseous working stream.

Apparatus for implementing a thermodynamic cycle comprising:

• a heater for superheating a gaseous working stream;
• means for expanding the superheated gaseous working stream to transform its energy into usable form;
• a first stream separator for dividing the expanded gaseous working stream into a withdrawal stream and a spent stream;
• a reheater for reheating the spent stream and means for expanding the reheated spent stream;
• first and second heat exchangers for cooling the withdrawal stream and the spent stream, after the expansion of the spent stream, the cooling of the withdrawal stream and the spent stream transferring heat used to superheat the gaseous working stream;
• a first stream mixer for combining the withdrawal stream with a lean stream, having a higher content of a high-boiling component than the withdrawal stream, to form a composite stream that condenses over a temperature range that is higher than the temperature range required to evaporate an oncoming liquid working stream;
• a third heat exchanger for condensing the composite stream to provide heat to partially evaporate the oncoming liquid working stream, transforming the liquid working stream into part of a gaseous working stream;
• a fourth heat exchanger for cooling and condensing the composite stream to preheat the lean and liquid working stream;
• means for expanding the composite stream to reduce the pressure of the composite stream;
• a fifth heat exchanger for partially evaporating a first portion of the expanded composite stream with heat transferred from a counterstream of the same composite stream, that has not yet been expanded, and a sixth heat exchanger enabling heat transferred from said spent stream to partially evaporate this first portion of the expanded composite stream;
• a gravity separator for separating the partially evaporated first portion of the composite stream to form a first liquid stream, that forms a portion of the lean stream, and a first vapor stream;
• a scrubber for combining the first vapor stream with a second portion of said expanded composite stream, and for enabling second vapor and second liquid streams to flow from said scrubber;
• a second stream mixer for combining said first liquid stream and said second liquid stream to form said lean stream;
• a first pump for pumping the lean stream to a higher pressure than the pressure of the first liquid stream that is produced from the separation of the partially evaporated first portion of the composite stream;
• a seventh heat exchanger for transferring heat from the spent stream, after it has transferred heat to the gaseous working stream, to the liquid working stream to evaporate the liquid working stream to form part of the gaseous working stream and an eighth heat exchanger enabling heat from the spent stream to preheat the liquid working stream;
• a third stream mixer for mixing the second vapor stream with a third portion of the expanded composite stream to form a pre-condensed working stream;
• a condenser for condensing the pre-condensed working stream to produce the liquid working stream;
• and
• a second pump for pumping the liquid working stream, after it flows from the condenser, to a higher pressure, before the liquid working stream is preheated in the fourth and eighth heat exchangers.