Abstract: Systems and methods operate to infer a fuel composition in a combustion system. The fuel composition may be inferred by receiving measured operating parameters including one or more of fuel data defining fuel characteristics used in combustion within a heater of the combustion system, emissions data defining emission gasses exiting the heater, airflow data defining ambient air being supplied to the heater and airflow rate of the air within the heater. One or more relationships within the measured operating parameters may be identified that result in a list of potential fuel compositions. One of the potential fuel compositions from the list may be selected having sufficient likelihood of resulting in the measured operating parameters as an inferred fuel composition. The output the inferred fuel composition to a heater controller of the combustion system and used for automatic control thereof.

Abstract: A demultiplexed filtering method includes propagating an optical beam from an input optical fiber to a diffraction grating to produce a first and a second diffracted beam having a respective first center wavelength ?1 and a second center-wavelength ?2>?1 of the optical beam. The first diffracted beam propagates back toward the input optical fiber at a first diffracted angle determined in part by ?1 and a diffraction order m1 of the first diffracted beam. The second diffracted beam propagates back toward the input optical fiber at a second diffracted angle determined in part by ?2 and a diffraction order m2<m1. The method also includes (i) coupling the first diffracted beam into a first optical fiber of a one-dimensional optical-fiber array that includes the input optical fiber, and (ii) coupling the second diffracted beam into a second optical fiber of the one-dimensional optical-fiber array.

Abstract: A laser-heterodyne combustion-efficiency monitor captures light emitted from a combustion zone during combustion and determines combustion efficiency based on the captured light. The monitor includes an optical detector that generates an electrical response by mixing the captured light with an optical local-oscillator signal, and a signal filter that filters the electrical response to isolate a beat-note that is proportional to a target-species concentration in the combustion zone. The frequency of the local-oscillator signal determines the target species, which may be carbon monoxide, carbon dioxide, or another emission or absorption line that can be detected using laser-heterodyne radiometry. A laser generates the local-oscillator signal. The monitor may be extended to operate with several lasers emitting several local-oscillator signals at different frequencies, thereby allowing multiple target species to be detected simultaneously.

Abstract: Combustion heater control systems and methods that include dynamic safety settings. Current operating parameters of the combustion heater are sensed at a plurality of time intervals and converted into a time-varying signal. The time-varying signal is compared to a burner stability envelope indicating when a burner is likely to enter an unstable state. The unstable state may include huffing, flashback, and/or liftoff. When the burner is likely to enter an unstable state, the combustion heater is controlled to prevent the unstable state.

Abstract: A multi-function sight port door includes a sensor mount attached at an aperture within the sight port door. A sensor is mounted to the sensor mount and configured to monitor the interior of a heater that the multi-function sight port door is mounted to. The multi-function sight port door is also configured to open to allow visual inspection of the interior of the heater while the sensor is mounted thereto. The multi-function sight port may be configured to allow for one or more of X-axis, Y-axis, Z-axis, tilt, roll, and yaw positioning of the sensor as mounted to the sight port door. The sensor may be a temperature sensor, pressure sensor, flame scanner, gas analyzer, optical-based sensor, thermal imager, thermal camera, or laser-based analyzer.

Abstract: Measuring a concentration of at least one target species is described. A first and second tunable diode laser are configured to generate laser light at a respective wavelength different from one another. A pitch head comprising a transmitting optic is optically coupled to the first and second tunable diode lasers via distal ends of the first and second optical fibers, and is oriented to project respective beams from each of the first and second distal ends through a measurement zone. A photodetector is configured to detect an optical power of light in the first and second wavelengths. A catch head located across the measurement zone from the pitch head is in optical communication with the pitch head to receive the respective beams from the first and second distal ends and direct the respective beams to the photodetector.

Abstract: Systems for measuring a concentration of a target species include a first and second tunable diode laser generating laser light at a respective first and second wavelength each corresponding to respective absorption lines of the target species. A first optical fiber is optically coupled to the first tunable diode laser, and does not support a fundamental mode at the second wavelength. A second optical fiber is coupled to the second tunable diode laser and does not support a fundamental mode at the first wavelength. A fiber bundle includes respective distal ends of the first and second optical fibers, which are stripped of their respective coatings and arranged with their claddings adjacent to each other. A pitch head is configured to project respective optical beams from the fiber bundle through a measurement zone. A catch head located across the measurement zone receives the projected beams and directs them to a sensor.

Abstract: Systems and methods for determining operating discrepancy a process heater. The discrepancy may be identified by solving a fired-systems model of the heater. The fired-systems model is then compared to current operating data. If the sensed current operating data is outside of the expected value(s), as defined by the fired-systems model, the systems and methods may take a remediation action to resolve the discrepancy. The discrepancy may include convection fouling identification and identification of tramp-air leaks within the process heater that are otherwise not easily detected by a human operator.

Abstract: Systems and methods iteratively solve a fired-systems model of the process heater based on fuel information, a target heat release of the plurality of burners, ambient air information, and available airflow at each of the plurality of burners to identify optimized burner air register settings to achieve a target global excess oxygen level to be sensed by the oxygen sensor. The optimized burner air register settings may be output to a heater controller of the process heater for control of the process heater.

Abstract: A multi-function sight port door includes a sensor mount attached at an aperture within the sight port door. A sensor is mounted to the sensor mount and configured to monitor the interior of a heater that the multi-function sight port door is mounted to. The multi-function sight port door is also configured to open to allow visual inspection of the interior of the heater while the sensor is mounted thereto. The multi-function sight port may be configured to allow for one or more of X-axis, Y-axis, Z-axis, tilt, roll, and yaw positioning of the sensor as mounted to the sight port door. The sensor may be a temperature sensor, pressure sensor, flame scanner, gas analyzer, optical-based sensor, thermal imager, thermal camera, or laser-based analyzer.

Abstract: A tunable diode laser absorption spectroscopy (TDLAS) optical head includes a housing configured for attachment to a sight tube attached to a wall of a process chamber. The TDLAS optical head further includes optics within the housing for transmitting, receiving, or transmitting and receiving a laser beam within a process chamber through the sight tube. The TDLAS optical head further includes a photo sensor in the housing positioned to receive light emitted by combustion within the process chamber to which the housing is attached.

Abstract: Systems for measuring a concentration of a target species include a first and second tunable diode laser generating laser light at a respective first and second wavelength each corresponding to respective absorption lines of the target species. A first optical fiber is optically coupled to the first tunable diode laser, and does not support a fundamental mode at the second wavelength. A second optical fiber is coupled to the second tunable diode laser and does not support a fundamental mode at the first wavelength. A fiber bundle includes respective distal ends of the first and second optical fibers, which are stripped of their respective coatings and arranged with their claddings adjacent to each other. A pitch head is configured to project respective optical beams from the fiber bundle through a measurement zone. A catch head located across the measurement zone receives the projected beams and directs them to a sensor.

Abstract: A method for measuring a concentration of at least one target species includes generating first and second laser beams having respective first and second wavelengths each corresponding to respective absorption lines of the at least one target species. The method includes coupling the first and second laser beams to proximal ends of first and second fundamental modes of first and second optical waveguides, respectively. The method includes transmitting through a measurement zone, for a distal end of the first and second optical waveguides, a probe signal including the first and second laser beam. The method includes determining a first signal strength of the probe signal at the first wavelength and a second signal strength of the probe signal at the second wavelength, and determining, from the first signal strength and the second signal strength, a concentration of the at least one target species.

Abstract: Sensing of gas species characteristics within a process chamber includes selectively projecting a beam of a first select lasing frequency therethough. The beam is optically coupled to a detector to detect a process transmission spectrum having an absorption dip at a select lasing frequency caused by a gas species characteristic. The beam is selectively projected through a fiber Bragg grating which is formed in an optical fiber core to partially reflect at least a portion of the beam of the first select lasing frequency while passing a remainder of the beam. The remainder of the beam has an FBG transmission spectrum mimicking the absorption dip at or near the select lasing frequency caused by a gas species characteristic of interest. It is optically coupled the detector. Outputs of the detector are monitored to compare the FBG transmission spectrum to any process transmission spectrum produced in the process chamber.