Method of efficiency and emissions performance improvement for the simple steam cycle
원문보기
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
F01K-007/34
F01K-019/00
출원번호
US-0707206
(2010-02-17)
등록번호
US-8453452
(2013-06-04)
발명자
/ 주소
Kravets, Aleksandr
출원인 / 주소
Veritask Energy Systems, Inc.
대리인 / 주소
Pergament Gilman & Cepeda LLP
인용정보
피인용 횟수 :
2인용 특허 :
7
초록▼
A method for improvement of a fossil fuel energy conversion into electrical energy for the simple sub- and supercritical steam cycle is proposed through introduction of additional regenerative cycle duties to improve the evaporation rate per unit of fuel burned, thus minimizing condenser heat loss o
A method for improvement of a fossil fuel energy conversion into electrical energy for the simple sub- and supercritical steam cycle is proposed through introduction of additional regenerative cycle duties to improve the evaporation rate per unit of fuel burned, thus minimizing condenser heat loss of the working media. The additional duties provide a supplemental energy credit in the form of heat input to a steam generator where a modified combustion process is realized to convert fossil fuel into carbon monoxide and hydrogen at atmospheric pressure and thus achieving an essential reduction of nitrogen oxides (NOx) formation. The additional duties also involve a direct contact heat transfer to recover latent and thermal energy, contained in the discharged combustion products to provide yet another energy credit that satisfies both conventional and/or added regenerative cycle duties. A water surplus is also achieved in the said process of heat recovery from the combustion products to significantly improve water usage of the simple steam plant. The proposed heat recovery process also minimizes coolant usage while achieving a complete water recovery from combustion products and maintaining draft capabilities in the stack.
대표청구항▼
1. A method of improving thermal and/or environmental performance of a steam cycle comprising the steps of: a) mixing at least a portion of a steam with at least one of: a fuel; one or more combustion products comprising carbon dioxide; and combustion products of fossil fuel in ambient air; andb) su
1. A method of improving thermal and/or environmental performance of a steam cycle comprising the steps of: a) mixing at least a portion of a steam with at least one of: a fuel; one or more combustion products comprising carbon dioxide; and combustion products of fossil fuel in ambient air; andb) supplying at least one of the steam, the mixture of the steam and the one or more combustion products, and the mixture of the fuel and the steam into a furnace of a boiler, thereby adding heat to a combustion process, enhancing partial fuel conversion into carbon monoxide and hydrogen, suppressing formation of nitrogen oxide(s) (“NOx”), and/or increasing steam evaporation with fuel burned, wherein at least one of:(i) the steam that is supplied into the furnace of the boiler is extracted from a steam turbine; and(ii) a high quality steam is extracted from a steam turbine and heat from the high quality steam is transferred to the steam or to a low quality water stream to generate the steam that is supplied into the furnace of the boiler within the steam cycle, the steam that is supplied into the furnace of the boiler being lower quality than the high quality steam used in the steam cycle. 2. The method of claim 1, wherein the supplying and/or mixing occurs proximately to boiler and/or the furnace in at least one of: an area of fuel injection; a pipe; a fuel injector; and a combustion zone in the furnace. 3. The method of claim 1, wherein the supplying and/or mixing occurs proximately to the boiler and/or the furnace and to a combustion zone in the furnace between the area of fuel injection through the main burners under sub-stoichiometric conditions and the area where the balance of the air is added for complete combustion to suppress NOx formed in the main combustion zone. 4. The method of claim 1, wherein the steam and/or the high quality steam extracted from the turbine comprises of: (i) a first portion of the steam and/or the high quality steam extracted from a low pressure or the lowest extraction point in a low pressure (“LP”) turbine; and (ii) a second portion of steam extracted from any extraction point having higher steam parameters than steam parameters of the extraction of the first portion, the second portion serving as a motive media in an eductor to compress the first portion of the steam and/or the high quality steam and supply the steam and/or the high quality steam into the combustion process. 5. The method of claim 4, further comprising reheating the steam and/or the extracted high quality steam from the steam turbine by mixing the steam and/or the extracted high quality steam with one or more combustion products before leaving the boiler and supplying the reheated mixture into a combustion zone of the furnace (combustion process) to increase heat input into the combustion process and improve the NOx suppression. 6. The method of claim 4, further comprising reheating the steam and/or the extracted high quality steam from the steam turbine by heating the steam and/or the extracted high quality steam in a designated heat transfer surface inserted into combustion products before leaving the boiler and supplying the reheated steam into a combustion zone of the furnace to increase heat input into the furnace (combustion process) and improve the NOx suppression. 7. The method of claim 4, further comprising: transferring an energy of the extracted steam and/or the extracted high quality steam to a lower quality (grade) water through an evaporator; andreheating the lower quality (grade) water with one or more combustion products before leaving the boiler to increase the additional heat input into the combustion process and improve the NOx suppression, whereinthe lower quality (grade) water evaporates into a lower quality steam and the lower quality steam operates to: enter into a combustion zone of the furnace and/or mix with the fuel stream to suppress emissions and prevents loss of the high quality steam, thereby improving one or more operating costs. 8. The method of claim 1, further comprising: adding oxygen to an oxidizer comprising ambient air to increase a temperature in a combustion zone for fuel with a low calorific value to increase the rate of fuel and steam reactions and/or fuel and combustion products to increase a fuel conversion rate into CO and hydrogen and/or to reduce NOx emissions. 9. The method of claim 1, further comprising: replacing a portion of a low temperature fuel transporting media comprising air and/or combustion products with steam before fuel injection into the furnace to increase the rate of fuel and steam reactions and/or fuel and combustion products to increase a fuel conversion rate into CO and hydrogen and/or to reduce NOx emissions. 10. The method of claim 1, wherein additional heat added to the combustion process produces additional steam in the boiler that is further partially expending through at least one section of the turbine before extraction from a low pressure section of the turbine such that the additional steam performs additional mechanical work while moving through the turbine to drive a generator to produce additional electrical output. 11. The method of claim 10, further comprising extracting the additional steam before a turbine condenser such that steam cycle loss in the condenser is diminished while power produced by the turbine increases. 12. The method of claim 7, wherein the lower quality steam and/or the lower quality water stream that evaporates into the lower quality steam comprises water other than cycle-feed water. 13. The method of claim 7, further comprising using the high quality steam for at least one of: indirect heating carbon dioxide prior to injection into the furnace; heating air-derived combustion products prior to injection into the furnace; drying coal before grinding; heating the fuel prior to injection into the furnace; and heating the fuel and other components selected from a group including at least one of: steam, carbon dioxide, and one or more combustion products. 14. The method of claim 7, further comprising: using the high quality steam and/or the lower quality steam as motive gas to drive a hot flue gas to mix with the fuel stream, wherein the mixing occurs in a pipe and/or a fuel injector proximate to the furnace. 15. The method of claim 14, further comprising: extracting a dry portion of the flue gas before entering a stack for at least one of: (i) preheating in a main air heater for coal drying and/or for further drying and transporting pulverized coal from a mill to a furnace; (ii) coal drying before supplying the coal to the mill; and (iii) bypassing a portion of the dry flue gas around a main air heater to control a temperature of the fuel leaving the mill and/or to maintain a coal drying temperature. 16. The method of claim 1, further comprising: directing an exit gas from the boiler into a vessel containing a water sprayer to directly absorb a low thermal energy heat from the flue gas; and supplying the heated water into at least one water-to-water heat exchanger, the water-to-water heat exchanger heats a feed water stream to the furnace to increase the work performed by the steam in the turbine, wherein the feed water comprises a condensate from a turbine condenser. 17. The method of claim 16, further comprising transferring at least a portion of the heat from the heated water to a low quality (grade) water in at least one water-to-water heat exchanger before evaporation of the low quality water, thereby recovering low energy heat. 18. The method of claim 16, further comprising transferring at least a portion of the heat from the heated water to combustion air in at least one water-to-gas heat exchanger before entering a main air heater, thereby recovering low energy heat. 19. The method of claim 16, further comprising adding steam from the cycle to the heated water to increase its heating potential for: (i) coal drying; and/or (ii) air preheating. 20. The method of claim 16, further comprising: saturating a flue gas that exits from the boiler to a first direct heat exchanger at elevated temperature, wherein the elevated temperature is between about 150° F. and about 200° F.; andsubmitting the saturated gas to a second surface heat exchanger to improve a cooling rate and to remove acidic moisture. 21. The method of claim 16, further comprising: partially and/or completely extracting one or more pollutants product(s) contained by the flue gas from at least one of the water-to-water heat exchanger, and the vessel containing a water sprayer; andperforming water treatment of the acidic liquid resulted from the heat-transfer process in a waste water plant to convert into by-products suitable for storage and/or safe disposal. 22. The method of claim 16, further comprising: taking the exit gas from the direct heat exchanger and piping the exit gas into a surface heat exchanger for cooling;adding ambient air or compressed air and water to promote condensation and to obtain a cool flue gas;piping the cool flue gas to a moisture separator to remove remaining (over-equilibrium) liquid moisture from flue gas; andreturning the gas to the surface heat exchanger for heating and to reduce and/or minimize consumption of ambient air or compressed air and water required for promoting moisture condensation from the flue gas entering the moisture separator. 23. The method of claim 22, further comprising: partially and/or completely extracting one or more pollutants product(s) contained by the flue gas from at least one of the first heat exchanger, the second heat exchanger, and the moisture separator; andperforming water treatment of the acidic liquid resulted from the heat-transfer process in a waste water plant to convert into by-products suitable for storage. 24. The method of claim 23, further comprising: partially and/or completely extracting the one or more pollutants product(s) before entering a stack, thereby reducing mist output through the stack to the atmosphere, wherein the one or more pollutants product(s) are captured and removed by water droplets in the moisture separator prior to exhaust to the atmosphere and the one or more pollutants product(s) include at least one of: gaseous phase of NOx; gaseous phase of sulfur oxides (“SOx”) comprising sulfur dioxide (“SO2”) gaseous phase and/or sulfur trioxide (“SO3”) gaseous phase; one or more heavy metals comprising arsenic, cadmium, and/or mercury; one or more acids comprising Chlorine and Sulfur; and one or more particulate matter comprising particulate matter 10 and/or particulate matter 2.5 (“PM10” and/or “PM 2.5”) captured in a dust collector. 25. The method of claim 23, further comprising: generating a water surplus from the treated products such that the water surplus is used for at least one of: as the make-up water in the steam cycle; for plant use in one or more cooling towers to cool circulation water from a turbine condenser; and to establish a reliable source of water supply for one or more other activities. 26. The method of claim 1, further comprising: saturating a flue gas that exits from the boiler to a first direct heat exchanger at an elevated temperature, wherein the elevated temperature is between about 150° F. and about 200° F.; andsubmitting the saturated gas to a second surface heat exchanger to improve a cooling rate and to remove acidic moisture, wherein the energy regain by the dry flue gas in the second surface heat exchanger operates to improve a natural draft through a stack. 27. The method of claim 1, further comprising reducing carbon dioxide (“CO2”) by up to and/or including ten percent due to a corresponding reduction of fuel consumption in the steam cycle. 28. A method of improving performance of a steam cycle comprising the steps of: transferring heat from a high quality steam to a low quality steam or to a low quality water stream to generate the low quality steam within the steam cycle, wherein the high quality steam is pure or substantially pure;mixing an amount of the low quality steam with at least one of a portion of a fuel stream and one or more combustion products to form a mixture; andheating the low quality steam and/or the mixture to release energy during combustion, wherein the energy is used to generate or heat steam. 29. The method of claim 28, further comprising: directing an exit gas from the boiler into a vessel containing a water sprayer to absorb a low thermal energy heat from the boiler exit gas; andsupplying the heated water into at least one water-to-water heat exchanger, the water-to-water heat exchanger heats a feed water stream to the furnace to increase the work performed by the steam in the turbine, wherein the feed water comprises condensate returning from a turbine condenser. 30. The method of claim 28, wherein additional heat added to the combustion process produces additional steam in the boiler that is further partially and/or completely expended through at least one section of the turbine before extraction from a low pressure section of the turbine such that the additional steam performs additional mechanical work while moving through the turbine to drive a generator to produce additional electrical output. 31. The method of claim 30, further comprising extracting the high quality steam before a turbine condenser such that steam cycle loss in the condenser is diminished while power produced by the turbine increases. 32. The method of claim 28, wherein the low quality steam and/or the low quality water stream that evaporates into the low quality steam comprises water other than cycle-feed water. 33. The method of claim 28, wherein the low quality steam that mixes with the fuel stream prevents loss of the high quality steam, thereby improving one or more operating costs. 34. The method of claim 28, further comprising using the high quality steam for at least one of: heating carbon dioxide prior to injection into the furnace; heating air derived combustion products prior to injection into the furnace; drying coal before grinding; heating the fuel prior to injection into the furnace; and heating the fuel and other components selected from a group including at least one of: steam, carbon dioxide, and one or more combustion products. 35. The method of claim 28, further comprising: using the high quality steam and/or the low quality steam as motive gas to drive a hot flue gas to mix with the fuel stream, wherein the mixing occurs in a pipe and/or a fuel injector proximate to the furnace. 36. The method of claim 29, further comprising: taking the exit gas from the direct heat exchanger and piping the exit gas into a surface heat exchanger for cooling;adding ambient air or compressed air and water to promote condensation and to obtain a cool flue gas;piping the cool flue gas to a moisture separator to remove remaining (over-equilibrium) liquid moisture from flue gas; andreturning the gas to the surface heat exchanger for heating and to reduce and/or minimize consumption of ambient air or compressed air and water required for promoting moisture condensation from the flue gas entering the moisture separator. 37. The method of claim 28, further comprising: saturating a flue gas that exits from the boiler to a first heat exchanger at an elevated temperature; andsubmitting the saturated gas to a second heat exchanger to improve a cooling rate and to remove acidic moisture, wherein a heat transfer surface of the second heat exchanger comprises one or more plates having frequent directional changes (wave profile) to improve separation of a polluted condensate from the flue gas. 38. The method of claim 36, further comprising: extracting one or more waste product(s) from at least one of the direct heat exchanger, the surface heat exchanger, and the moisture separator; andperforming water treatment and/or acidic liquid treatment on the one or more extracted waste products. 39. The method of claim 38, further comprising: generating a water surplus from the treated product(s) such that the water surplus is at least one of: (i) used as the make-up water in the steam cycle; returned to the direct heat exchanger to control outlet temperature from direct heat exchanger and/or to maintain heated liquid pH close to neutral, thereby allowing the use of less expensive construction material(s); and/or to establish a reliable source of water supply for one or more other activities. 40. The method of claim 1, wherein at least one of the fuel and the fossil fuel comprises at least one of: (i) a first fuel that operates to be used for a steam cycle operation;(ii) at least a portion of a first fuel used in a steam cycle operation;(iii) at least a portion of a second fuel, either fossil or man-made, of different origin from the first fuel, the second fuel being in a form of at least one of gaseous, liquid, and solid fuel that supplements, or substitutes with, at least a portion of the first fuel used for a steam cycle operation; and(iv) at least one of the first fuel and the second fuel comprises at least one of: a gas, a natural gas, a coal, an oil, a hydrocarbon fuel, a carbon-based fuel, a man-made fuel, a fossil fuel, and a solid fuel. 41. The method of claim 1, wherein one or more combustion products are at least one of: (i) a portion of products consisting predominantly of carbon dioxide derived from one or more products of a complete and rapid fuel oxidation in ambient air or oxygen-enriched air or in a 100% oxygen atmosphere; and(ii) a portion of the combustion products resulted from rapid fuel oxidation in ambient air or oxygen-enriched air or in a 100% oxygen atmosphere. 42. The method of claim 28, wherein one or more combustion products are: (i) a portion of products consisting predominantly of carbon dioxide derived from one or more products of a complete and rapid fuel oxidation in ambient air or oxygen-enriched air or in a 100% oxygen atmosphere; and(ii) a portion of the combustion products resulted from rapid fuel oxidation in ambient air or oxygen-enriched air or in a 100% oxygen atmosphere. 43. The method of claim 2, wherein at least one of: (i) combustion is a series of rapid chemical oxidation and reduction reactions of two or more substances or reactants, including at least a fuel and an oxidant, with a characteristic liberation of heat and light, providing that: (a) heat liberation exceeds a specific activation energy to establish a self-sustained combustion process; (b) sufficient time and at least a sufficient amount of oxidant as required to complete the chemical reaction are provided; (c) the said reactants convert into chemically inert products or combustion products or flue gas, where the chemically inert products or the combustion products or the flue gas represent a mixture of primarily incombustible elements that cannot undergo any further chemical reaction under their physical conditions; and (d) the composition of the combustion products or the flue gas depends on the compositions of the reactants including the fuel and the oxidant;(ii) the combustion zone is a portion of the boiler furnace where all or a major portion of fuel and an oxidant required to operate the steam cycle are supplied through one or more main burners, and where the combustion zone further substantially includes products of the incomplete (intermittent) fuel and oxidant reaction which remain chemically active under local physical conditions within the combustion zone;(iii) a sub-stoichiometric combustion is a self-sustained chemical oxidation and reduction reaction of all or a major portion of fuel required to generate power in the steam cycle while a shortage of an oxidation reactant is created within a second combustion zone by design to prevent a complete combustion of the fuel supplied within the combustion zone; and(iv) an area within the boiler furnace where the balance of air is added to complete the combustion process downstream of a sub-stoichiometric combustion zone and obtain predominantly complete product(s) of combustion, including flue gas. 44. The method of claim 3, wherein at least one of: (i) combustion is a series of rapid chemical oxidation and reduction reactions of two or more substances or reactants, including at least a fuel and an oxidant, with a characteristic liberation of heat and light, providing that: (a) heat liberation exceeds a specific activation energy to establish a self-sustained combustion process; (b) sufficient time and at least a sufficient amount of oxidant as required to complete the chemical reaction are supplied; (c) the said reactants convert into one or more chemically inert products or more combustion products or flue gas, where the chemically inert products or the combustion products or the flue gas represent a mixture of primarily incombustible elements that cannot undergo any further chemical reaction under their physical conditions; and (d) the composition of the combustion products or the flue gas depends on the compositions of the reactants including the fuel and the oxidant;(ii) the combustion zone is a portion of the boiler furnace where all or a major portion of fuel and an oxidant required to operate the steam cycle are supplied through one or more main burners, and where the combustion zone further substantially includes products of the incomplete (intermittent) fuel and oxidant reaction which remain chemically active under local physical conditions within the combustion zone;(iii) a sub-stoichiometric combustion is a self-sustained chemical oxidation and reduction reaction of all or a major portion of fuel required to generate power in the steam cycle while a shortage of an oxidation reactant is created within a second combustion zone by design to prevent a complete combustion of the fuel supplied within the combustion zone; and(iv) an area within the boiler furnace where the balance of air is added to complete the combustion process downstream of a sub-stoichiometric combustion zone and obtain complete product(s) of combustion, including flue gas. 45. The method of claim 4, wherein at least one of: (i) at least one of the high quality steam and its respective condensate derived from the boiler feed water include a low or minimal level of one or more chemical impurities that is required for reliable long-term boiler and turbine operation; and(ii) at least one of the steam, a low quality steam and water at least one of: (a) includes larger quantities of chemical impurities as compared to those found in boiler feed water; and(b) is derived from the source other than water and/or steam required for the steam cycle operation. 46. The method of claim 1, wherein the fuel stream comprises a carbon based fuel having either fossil or man-maid origin and is determined by the generic formula CnHmNiOjSk, where index n>0, representing that the quantity of the Carbon element (C) in the fuel is always greater than zero, and where the other indices, i.e., m, i, j and k, representing quantities of other elements in the fuel, i.e., Hydrogen (H), Nitrogen (N), Oxygen (O), and Sulfur (S), respectively, operate to be equal to or greater than zero. 47. The method of claim 28, wherein the fuel stream comprises a carbon based fuel having either fossil or man-maid origin and is determined by the generic formula CnHmNiOjSk, where index n>0, representing that the quantity of the Carbon element (C) in the fuel is always greater than zero, and where the other indices, i.e., m, i, j and k, representing quantities of other elements in the fuel, i.e., Hydrogen (H), Nitrogen (N), Oxygen (O), and Sulfur (S), respectively, operate to be equal to or greater than zero. 48. The method of claim 41, wherein the fuel stream comprises a carbon based fuel having either fossil or man-maid origin and is determined by the generic formula CnHmNiOjSk, where index n>0, representing that the quantity of the Carbon element (C) in the fuel is always greater than zero, and where the other indices, i.e., m, i, j and k, representing quantities of other elements in the fuel, i.e., Hydrogen (H), Nitrogen (N), Oxygen (O), and Sulfur (S), respectively, operate to be equal to or greater than zero. 49. The method of claim 28, wherein at least one of: (i) the low quality water stream comprises at least one of a low energy water stream;(ii) the low quality water stream recovers waste energy contained in the combustion products and steam operated within steam cycle to generate a low quality steam; and(iii) the low quality steam supplements fuel heat input into the boiler furnace or combustion zone(s). 50. The method of claim 4, wherein the first potion of the steam is the low quality steam generated from the low quality water. 51. The method of claim 1, wherein the high quality steam is pure or substantially pure. 52. The method of claim 51, wherein at least one of: (i) the purity or substantial purity of the high quality steam is such that the high quality steam includes at least one of: no traces of chemical impurities and/or gases, traces of chemical impurities and/or gases, and a low or minimal level of one or more chemical impurities and/or gases for reliable long-term boiler and/or turbine operation; and(ii) the high quality steam is more pure or more substantially pure than the low quality steam or the low quality water stream from which the low quality steam is generated. 53. The method of claim 28, wherein at least one of: (i) the purity or substantial purity of the high quality steam is such that the high quality steam includes at least one of: no traces of chemical impurities and/or gases, traces of chemical impurities and/or gases, and a low or minimal level of one or more chemical impurities and/or gases for reliable long-term boiler and/or turbine operation; and(ii) the high quality steam is more pure or more substantially pure than the low quality steam or the low quality water stream from which the low quality steam is generated. 54. The method of claim 28, wherein at least one of: (i) the high quality steam includes a low or minimal level of one or more chemical impurities that is required for reliable long-term boiler and turbine operation; and(ii) at least one of the steam, a low quality steam and water at least one of: (a) includes larger quantities of chemical impurities as compared to those found in boiler feed water; and(b) is derived from the source other than water and/or steam required for the steam cycle operation. 55. A method of improving thermal and/or environmental performance of a steam cycle comprising the steps of: a) mixing at least a portion of a steam with at least one of: a fuel; one or more combustion products comprising carbon dioxide; and combustion products of fossil fuel in ambient air; andb) supplying at least one of the steam, the mixture of the steam and the one or more combustion products, and the mixture of the fuel and the steam into a furnace of a boiler, thereby adding heat to a combustion process, enhancing partial fuel conversion into carbon monoxide and hydrogen, suppressing formation of nitrogen oxide(s) (“NOx”), and/or increasing steam evaporation with fuel burned, wherein:the supplying and/or mixing occurs proximately to the boiler and/or the furnace and to a combustion zone in the furnace between the area of fuel injection through the main burners under sub-stoichiometric conditions and the area where the balance of the air is added for complete combustion to suppress NOx formed in the main combustion zone; andat least one of: (i) the steam is extracted from a steam turbine; and (ii) a high quality steam is extracted from a steam turbine and heat from the high quality steam is transferred to the steam or to a low quality water stream to generate the steam within the steam cycle, the steam being lower quality than the high quality steam used in the steam cycle.
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