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Continuous real time heating value (btu)/coal flow balancing meterRelated Patent Categories: Furnaces, With Control Means Responsive To A Sensed ConditionContinuous real time heating value (btu)/coal flow balancing meter description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070251432, Continuous real time heating value (btu)/coal flow balancing meter. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS-REFERENCE TO RELATED APPLICATIONS [0001] Not Applicable STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT [0002] Not Applicable BACKGROUND OF THE INVENTION [0003] 1. Field of Invention [0004] The present invention relates to the use of nuclear response measurements of fuel flow and fuel quality combined with a process control system for optimization of air and coal stoichiometry at each burner in a coal fired boiler. [0005] 2. Description of the Related Art [0006] In the field of coal fired boilers used especially by utility companies and industrial boiler operators, it is well known that increasingly stringent emissions limits continue to apply pressure to reduce NO.sub.x emissions from coal fired boilers. Years of investigation by utilities, boiler suppliers, and controls suppliers have determined that stoichiometries local to the burners must be maintained to achieve very low NO.sub.x emissions without negatively effecting combustion efficiency or boiler performance. Common barriers to lower NO.sub.x emissions include poor coal and air distribution which may also lead to high unburned carbon, high CO.sub.x, boiler slagging, and oxygen and/or steam temperature imbalances. [0007] To date, all low NO.sub.x firing systems are based on a pre-defined balance of air and coal at the burners. Deviations from the design air/fuel balance at individual burners results in burners operating at a fuel lean or fuel rich condition. A fuel lean burner produces high NO.sub.x levels at elevated O.sub.2 resulting in a flue gas with high CO.sub.x, high NO.sub.x, and increased LOI due to burners operating with poor stoichiometries. A fuel rich burner produces large amounts of CO.sub.X, high LOI, and longer flames while lowering the oxygen level in the flue gas. Many coal fired boilers with poor air/fuel distribution experience problems such as: emission problems; increased unburned carbon in fly ash; distorted oxygen profile at the boiler outlet; uneven steam temperature profiles; flame impingement; increased slagging; and water wall heat waste. [0008] The inventor of the present invention is a co-inventor of the subject matter disclosed in U.S. Pat. No. 7,006,919, titled "Real time continuous elemental measurement of bulk material," issued on Feb. 28, 2006. In that patent, various methods and an apparatus for continuous real-time measurement of bulk material using gamma irradiation and neutron irradiation is disclosed. The '919 device includes a dual-energy gamma attenuation (DGA) device for monitoring bulk material flow and for producing a spectrum that is compared to a baseline spectrum to produce a relative weight/impurity ratio. A prompt gamma neutron activation analysis (PGNAA) device monitors the same bulk material flow and produces a spectrum that is compared to a library of spectrums to produce a relative component ratio. The relative component ratio is processed with the relative weight/impurity ratio to produce an absolute weight and impurity value, which is then processed with the relative component ratio to produce absolute component, or analyte, values. [0009] The DGA analysis technique involves bombarding a bulk material with gamma rays from two gamma ray emitters of sufficiently different energies. The gamma rays interact with the bulk material resulting in the attenuation of the number of gamma rays transmitted through the bulk material. The gamma rays are typically detected by a scintillation crystal (typically NaI). The sum of these released gamma rays at these specific energies is referred to as an energy spectrum. The technology relies on the fact that elements with different atomic numbers attenuate gamma rays at specific energies in different ways. Thus, for low-energy gamma rays (i.e., those generated by a low energy gamma emitter such as Am-241), the attenuation of gamma rays is largely dependent on the atomic number of the atoms/elements present in the bulk material. For high-energy gamma rays (i.e., those generated by a high-energy gamma emitter such as Cs-137), attenuation is independent of the atoms/elements in the bulk material. Analysis of the energy spectrum leads to a determination of the bulk elemental composition of the bulk material. [0010] DGA based sensors are known in the art. DGA devices are based on the premise that analyzed material will attenuate different energy gamma rays in fixed repeatable ways. A DGA device consists of a gamma energy source arrangement consisting of dual energy gamma emitters. The gamma emitters are chosen in such a way that the material to be analyzed will attenuate the different energy gamma rays in ways that are conducive to measuring one or more specific properties of the material being measured. One such application of DGA technology uses gamma ray sources to interrogate coal, with the assumption that the material of which the coal is composed will attenuate the differing energy gamma rays to produce a measurement that is conducive to determining coal ash content and density. [0011] The PGNAA technique involves bombarding a bulk material sample with neutrons from a neutron emitter (typically Cf-252). The neutrons collide with atoms/elements in the sample, emitter housing, and/or an external moderator and are captured by the nuclei of atoms/elements present in the sample. The capture process often involves the release of gamma rays at energies specific to the captured atom/element. These gamma rays are detected typically by a scintillation crystal (typically NaI). The sum of the detected gamma energy at these specific energies is an energy spectrum. Analysis of the energy spectrum provides analytical information on the proportion of the various elements present in the bulk material. [0012] As discussed in the '919 patent, various PGNAA based sensor systems are known. One such analyzer is that described in U.S. Pat. No. 4,582,992, titled "Self-Contained, On-Line, Real-time Bulk Material Analyzer," issued to Atwell, et al., on Apr. 15, 1986, which uses PGNAA technology in an attempt to determine the elemental content of the bulk material. The described analyzer uses an arrangement of neutron sources and gamma ray detectors in an enclosed assembly to perform its analysis. A similar device, described in U.S. Pat. No. 6,362,477, titled "Bulk Material Analyser for OnConveyor Belt Analysis," issued to Sowerby, et al., on Mar. 26, 2002, uses PGNAA technology in a bulk material on-conveyor belt arrangement to analyze bulk material. Again, this analyzer uses a neutron source and gamma ray detectors in an enclosed assembly to perform its analysis. BRIEF SUMMARY OF THE INVENTION [0013] The present invention is a method and an apparatus for continuous real time heating value/coal flow balancing of coal from a coal feeder to a burner. The apparatus includes a dual-energy Gamma Attenuation (DGA)/multi-energy Gamma Attenuation (MGA) device for measuring coal quality at a specific location (i.e., on the coal feeder tube between the coal silo and the mill) in a coal fired plant in order to control the parameters of the plant according to the measured coal quality. By strategically placing the DGA/MGA device, continuous accurate real-time coal quality information is accomplished for making individual adjustments in order to improve stoichiometry to optimize performance of the system. [0014] A system incorporating the apparatus of the present invention is includes a coal silo for receiving and burning coal. A DGA/MGA device includes at least one DGA/MGA source and at least one DGA/MGA detector in a fixed position relative to the coal silo. The analyzed coal flows onto a coal feeder conveyor or is otherwise moved to a mill. The coal is pulverized before being combined with air by way of at least one actuated damper. The dampers are electrically or electromechanically operated to open and close to adjust the volume of air introduced into the pulverized coal. The resulting product is then delivered to at least one burner. [0015] Quality information pertaining to the coal is determined by the DGA/MGA device and then sent to a processor. The processor is provided for varying the control of various system components based upon the coal quality information received from the DGA/MGA device. [0016] A time delay is established between the time the coal is passed through the coal silo feeder tube, at which point the coal is analyzed by the DGA/MGA device, and the time that the coal is processed through the dampers. The processor uses the coal quality information pertaining to the coal and the known time delay to adjust the actuated dampers, thereby controlling the amount of air mixed with the coal for optimal burner stoichiometry. Thus when a selected volume of coal is analyzed and particular settings at the dampers are required for that volume, the processor waits a predetermined time equal to the time delay before adjusting the dampers. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS [0017] The above-mentioned features of the invention will become more clearly understood from the following detailed description of the invention read together with the drawings in which: [0018] FIG. 1 is a block diagram of the proposed system; [0019] FIG. 2 is a representative diagram of the online measurement process; and Continue reading about Continuous real time heating value (btu)/coal flow balancing meter... Full patent description for Continuous real time heating value (btu)/coal flow balancing meter Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Continuous real time heating value (btu)/coal flow balancing meter patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Continuous real time heating value (btu)/coal flow balancing meter or other areas of interest. ### Previous Patent Application: Protection method and protection system for valuables Next Patent Application: Method and plant for processing waste Industry Class: Furnaces ### FreshPatents.com Support Thank you for viewing the Continuous real time heating value (btu)/coal flow balancing meter patent info. 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