Partially-open gas turbine cycle providing high thermal efficiencies and ultra-low emissions

• US 6,532,745 B1
• Filed: 04/10/2002
• Issued: 03/18/2003
• Est. Priority Date: 04/10/2002
• Status: Expired due to Fees

• Current Assignee: AES Development Company Incorporated
• Original Assignee: David L. Neary
• Inventors: Neary, David L.
• Primary Examiner(s): KIM, TAE JUN
• Application Number:
  US10/119,915
• Time in Patent Office: 342 Days
• Field of Search: 607/84, 607/85, 60/395.2, 60/394.1, 607/37
• US Class Current: 60/784
• CPC Class Codes: F02C 1/005 being recirculated
• CPC Class Codes: F02C 1/08 Semi-closed cycles
• CPC Class Codes: F02C 3/34 with recycling of part of the working fluid, i.e. semi-closed cycles with combustion products in the closed part of the cycle
• CPC Class Codes: Y02E 20/14 Combined heat and power generation [CHP]

Abstract

A partially-open turbine cycle for use with a modified gas turbine wherein the cycle'"'"'s working motive fluid replaces the predominant air-derived nitrogen working motive fluid contained in a conventional gas turbine cycle. The working motive fluid comprises a mixture of predominantly carbon dioxide and water vapor in a Mol percent ratio identical to that of the same molecular components Mol percentage as generated from the combustion of the fuel used. The cycle'"'"'s is susceptible to a 98 percent reduction of fugitive nitrogen oxide and carbon monoxide mass flow emissions as emitted by present art gas turbines on a rated shaft-horsepower basis, and is further susceptible to high simple cycle and cogeneration plant thermal efficiencies at greatly reduced operating pressures.

Claims

1. A partially-open gas turbine cycle for use with a modified gas turbine or comparable functioning turbine cycle train components producing mechanical output power and residual exhaust energy, the said cycle hereafter referred to as the AES Turbine Cycle comprising:

(a) AES Turbine Cycle working motive fluid and power turbine exhaust comprising a highly superheated mixture of predominant carbon dioxide and water vapor in Mol percent ratio proportions identical to that of the carbon dioxide and water vapor generated from combustion of the employed gaseous or liquid hydrocarbon fuel;

(b) a compressor means for raising the pressure of a low superheat recycled turbine exhaust gas stream, said stream of increased pressure recycled turbine exhaust gas hereafter referred to as the primary recycle gas stream;

(c) two or more primary recycle gas heat exchanger means conduit-positioned in parallel downstream from the said compressor means for extracting heat energy from the said primary recycle gas stream;

(d) said primary recycle gas heat exchanger means conduit manifold-connected to downstream positioned turbine exhaust gas waste heat recovery unit (WHRU) heat exchanger fluid manifold;

(e) said two or more heat exchangers downstream from the said compressor means, wherein the compressor'"'"'s discharge gas heat contained within said primary recycle gas flow is transferred to air or to a facility'"'"'s provided streams of process gas or steam, said compressor primary recycle gas flow being proportioned as required between plural exchangers by individual control valve means positioned within each said heat exchanger'"'"'s parallel outlet branch'"'"'s manifold conduit means;

(f) a turbine exhaust gas waste heat recovery unit (WHRU) heat exchanger means conduit-positioned downstream of a power turbine for transfer of power turbine exhaust gas residual heat energy to fluid coils contained within two or three parallel sections comprising said WHRU heat exchanger;

(g) a said WHRU heat exchanger collectively comprising a primary section containing parallel primary recycle gas stream coils as well as secondary and/or auxiliary sections containing steam or process fluid coils;

(h) conduit end-manifold parallel branches positioned downstream of said compressed recycle gas heat exchangers and containing individual control damper valve means for distributing the primary recycle manifold gas stream between parallel first and second primary recycle stream coils within the primary section of said WHRU heat exchanger, said parallel primary recycle gas stream coils discharging highly superheated first and second working motive fluid streams;

(i) conduit manifold branches and control damper valve means for distributing the power turbine exhaust gas mass flows between the said parallel sections of the said turbine exhaust gas WHRU heat exchanger, said manifold branch and damper control valve means connected to the downstream cool exhaust plenum sections side of said WHRU heat exchanger;

(j) manifold means for distributing said first flow-controlled stream portion of working motive fluid to one or more premixer subassemblies to establish a maximum temperature of primary and secondary zone combustion chemical reactions, said premixer subassemblies being direct means-connected to the exterior or interior of one or more combustion chamber assemblies, said manifold means positioned downstream of the fluid stream'"'"'s said WHRU heat exchanger having a primary first stream discharge header;

(k) manifold means for distributing said second flow controlled stream portion of the said working motive fluid to one or more said combustor assemblies for establishing a reduced controlled temperature tertiary zone at outlets of the said combustor assemblies, said manifold means positioned downstream of the fluid stream'"'"'s said WHRU heat exchanger having a primary section second stream discharge header;

(l) conduit and control valve means for distributing a predominant oxygen stream to one or more said premixer subassemblies;

said conduit and valve means positioned upstream of said premixer subassemblies;

(m) conduit and control valve means for distributing pressurized gaseous or liquid hydrocarbon fuel to one or more said premixer subassemblies;

(n) one or more said combustor assemblies downstream from the said WHRU heat exchanger'"'"'s primary section, said combustor assemblies comprising regions wherein the ignition and combustion chemical reactions occur, producing water vapor, carbon dioxide, and heat of combustion absorption by said working motive fluid;

(o) a power turbine assembly downstream of the said combustor assemblies for receiving the combustor gases predominantly comprising the working motive fluid and products of combustion at elevated temperature and pressure, the said combustor gases being expanded within said power turbine to produce mechanical output power and residual superheated exhaust gas heat energy;

(p) a power turbine assembly with output shaft series-train means of transmitting horsepower to drive rotating mechanical equipment or electrical generators with electric power conduit connections to a facility'"'"'s control room containing generator switchgear and MCC modular cabinets;

(q) manifold or conduit series positioned means conveying the downstream superheated exhaust gases from the said power turbine through said turbine exhaust WHRU heat exchanger and series continuing thereafter to a final downstream conduit-positioned turbine exhaust heat exchanger creating a turbine exhaust gas temperature slightly above its dewpoint temperature;

(r) a turbine exhaust gas distribution manifold conduit-positioned downstream of the said final turbine exhaust heat exchanger, said heat exchanger conduit-routing a majority of the turbine exhaust mass flow to the inlet of the cycle'"'"'s said compressor means, thereby completing the closed portion of said AES gas turbine cycle;

(s) conduit and control valve means for venting excess steady-state gas turbine exhaust mass flow from the said turbine exhaust gas distribution manifold into the atmosphere, said vented excess gas turbine exhaust providing the open portion of said AES gas turbine cycle wherein the said vented exhaust comprises a mass flow rate of low superheated temperature carbon dioxide and water vapor equating to the mass flow rate of the said AES gas turbine cycle'"'"'s generated mass products of combustion;

(t) a master PLC control panel that exercises both safety monitoring functions and all control valves positioning in response to the said master control panel'"'"'s coordination of both the AES Turbine Cycle'"'"'s mechanical power output and fluid heat recovery demands imposed on the operating cycle.

2. A partially-open gas turbine cycle of claim 1, wherein a conduit manifold-connected means provides the fluid flow connection between the compressed recycle gas heat exchangers and the turbine exhaust WHRU heat exchanger, said conduit-connected means therein having lesser flow portions of the total primary recycle low superheat temperature gas that are extracted from first and second side-branch connections positioned upstream of said turbine exhaust WHRU heat exchanger, said first side-branch connection having end-connected conduit means wherein a control valve regulates a flow of compressed recycle gas to downstream-positioned one or more premixer assemblies, said second-branch connection having end-connected conduit means wherein a flow of compressed recycle gas is conveyed to the inlet of a secondary recycle compressor.

3. A secondary recycle gas compressor recited in claim 2, wherein the compressor type comprises that of a motor-driven low pressure ratio radial centrifugal or positive displacement modular designed compressor unit with motor speed-control design features.

4. A partially-open gas turbine cycle of claim 1, wherein a conduit and control valve means provides a regulated fluid flow stream distributing a predominant oxygen stream, said predominant oxygen stream comprising a venturi gas mixer produced homogeneous mixture of pressurized secondary recycle compressor discharge gas and a controlled rich oxygen stream supplied by a facility'"'"'s separate auxiliary modular air separation system.

5. A partially-open turbine cycle of claim 1, wherein the recited cycle'"'"'s compressor comprises one or more stages of axial or radial centrifugal or positive displacement design or combination of these design types thereof and direct-driven by the recited power turbine assembly or independently driven by other than said power turbine assembly.

6. A partially-open gas turbine cycle of claim 1, wherein the recited compressor means possesses compressor flow control means comprising shaft speed changes by the further recited power turbine assembly or by either the said compressor'"'"'s internal flow control means or by separate variable speed drive means.

7. A partially-open gas turbine cycle of claim 1, wherein the recited conduit and control valve means for venting excess steady-state gas turbine exhaust to atmosphere, said control valve further performs a back-pressure control function to maintain the additionally recited turbine exhaust gas distribution manifold at a fixed desired internal absolute pressure.

8. A partially-open gas turbine cycle of claim 1, wherein one or more combustor assemblies and power turbine assembly have closely interconnecting conduit transition means or other means of one directly connecting to the another.

9. A partially-open gas turbine cycle of claim 1, wherein the power turbine assembly comprises one or more individual series-positioned hot gas expansion stages of conventional gas turbine axial flow design or alternative radial flow design.

10. A partially-closed gas turbine cycle of claim 1, wherein the power turbine assembly with output shaft series-train means therein further comprising shaft couplings and alternately gearbox means to adapt the power turbine assembly output shaft speed to the required speed of driven rotating mechanical equipment or electrical generators.

11. A partial-open gas turbine cycle of claim 1, wherein the primary recycle gas heat exchanger coil means has its heat absorbing fluid flow serially conduit-connected to the recited secondary section of the further recited turbine exhaust (WHRU) heat exchanger for cogeneration cycle applications and or to further recited final turbine exhaust heat exchanger series conduit-positioned downstream of the said WHRU.

12. A partially-open gas turbine cycle of claim 1, wherein flow controlling damper valves contained within turbine exhaust and primary recycle gas conduits are control-positioned as required by the further recited master PLC control panel upon receipt of mass flow data transmitted from computing sensor means positioned within the same said conduits.

13. A partially-open gas turbine cycle of claim 1, wherein the master PLC control panel comprising safety monitoring and control design features for both AES Turbine Cycle and driven mechanical rotating equipment applications are in accordance with API 616 or API RP 11PGT specifications, said master PLC control panel further comprising expandable control features for control integration with power cycle-complementing auxiliary systems'"'"' PLC control panels and a facility'"'"'s power plant distributive control system (DCS).