Boulder, CO, United States
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Sappey A.,Zolo Technologies | Heilbrunn G.,Zolo Technologies
AIChE Ethylene Producers Conference Proceedings | Year: 2016

Operators are often challenged to maintain well-balanced, uniform combustion across a large fired heater in order to optimize efficiency, reliability, production yields, and safety and to reduce emissions. While most large furnaces and heaters have several individual sensors available to monitor temperature, O2, and CO, typically at the furnace exit, the number of such sensors available for use directly inside the firebox is very limited. This paper describes a novel but well-proven wavelength-multiplexed, laser-based monitoring and diagnostic technology that measures temperature, oxygen, and carbon monoxide directly in the high temperature zone of combustion furnaces and heaters. Because of the fiber-coupled nature of the system, multiple locations (up to 24 lines of sight) can be measured with a single system. Utilization of wavelength-multiplexed tunable diode laser absorption spectroscopy (TDLAS) laser systems for continuous reporting of multiple combustion gases across the radiant and convective zones of a combustion process represents a first-of-its-kind application for TDLAS technology. It allows operators to tune burner controls to achieve fuel savings, increase production yields, lower excess 02, monitor CO, reduce NOx and CO2 emissions, and extend furnace tube/coil life through well-balanced temperature and oxygen profiles across the entire envelope of the heater. This paper describes the design, use, and value of wavelength-multiplexed TDLAS laser technology as applied to large furnaces. © 2016, American Institute of Chemical Engineers. All rights reserved.


Affelt S.,Zolo Technologies
Power Engineering (Barrington, Illinois) | Year: 2011

In 2010, the US Department of Energy's National Energy Technology Laboratory (NETL) sponsored demonstration projects to reduce CO2/MWh using generation efficiency improvements through combustion balancing at two coal-fired power plants. The projects, led by Zolo Technologies, used the ZoIoBOSS real-time combustion monitor to balance combustion coupled with closed-loop combustion optimization software to sustain improvements. The ZoIoBOSS layouts at each plant were customized to adopt the furnace characteristics, burner configuration and access or obstructions at the furnace wall. Two alternative methods for determining efficiencies were evaluated, Input/Output (10) and Heat Loss (HL) methods both confirmed significant improvements in heat rate. The results showed improvement in boiler efficiency with savings in both fuel and auxiliary power as a result of manual and optimizer tuning. Reductions of CO2/MWh of 2.43% and 2.34% were calculated following manual and optimizer tuning.


Grover S.,University of Colorado at Boulder | Dmitriyeva O.,University of Colorado at Boulder | Estes M.J.,Zolo Technologies | Moddel G.,University of Colorado at Boulder
IEEE Transactions on Nanotechnology | Year: 2010

We evaluate a technique to improve the performance of antenna-coupled diode rectifiers working in the IR. Efficient operation of conventional, lumped-element rectifiers is limited to the low terahertz. By using femtosecond-fast MIM diodes in a traveling-wave (TW) configuration, we obtain a distributed rectifier with improved bandwidth. This design gives higher detection efficiency due to a good match between the antenna impedance and the geometry-controlled impedance of the TW structure. We have developed a method for calculating the responsivity of the antenna-coupled TW detector. Three TW devices, made from different materials, are simulated to obtain their impedance and responsivity at 1.5, 3, 5, and 10 μm wavelengths. The characteristic impedance of a 100-nm-wide TW is in the range of 50 Ωand has a small variation with frequency. A peak responsivity of 0.086 A/W is obtained for the Nb- Nb 2O 5Nb TW diode at 3-μm wavelength. This corresponds to a quantum efficiency of 3.6% and is a significant improvement over the antenna-coupled lumped-element diode rectifiers. For IR imaging, this results in a normalized detectivity of 4 × 10 6 Jones at 3 μm. We have identified several ways for improving the detectivity of the TW detector. Possible methods include decreasing the diode resistance, reducing the noise, and increasing the effective antenna area. © 2010 IEEE.


A method of monitoring combustion properties in an interior of a boiler of the type having walls comprising a plurality of parallel steam tubes separated by a metal membrane. First and second penetrations are provided in the metal membrane between adjacent tubes on opposite sides of the boiler. A beam of light is projected through a pitch optic comprising a pitch collimating lens and a pitch relay lens, both residing outside the boiler interior. The pitch relay lens projects the beam through a penetration into the boiler interior. The beam of light is received with a catch optic substantially identical to the pitch optic residing outside the boiler interior. The strength of the collimated received beam of light is determined. At least one of the pitch collimating lens and the catch collimating lens may then be aligned to maximize the strength of the collimated received beam.


A method of absorption spectroscopy to determine a rapidly variable gas parameter. The method includes transmitting light from a synchronization light source to a synchronization detector. The transmitted light is periodically interrupted by a moving mechanical part between the synchronization light source and synchronization detector. The output from the synchronization detector is used to generate a repeating time signal having variable phase delay. This signal is used to control the timing of laser spectroscopy wavelength scans. Multiple spectroscopic scans may be repeated at multiple selected time signal phase delay and the results averaged for each phase. Apparatus for implementing the above methods are also disclosed.


Patent
Zolo Technologies | Date: 2010-08-10

An apparatus and methods for measuring combustion parameters in the measurement zone of a gas turbine engine. The measurement zone is defined as being between an outer casing and an engine component having a reflecting surface inside the outer casing. The apparatus comprises a laser generating a transmitting beam of light of a select wavelength and a multimode transmitting fiber optically coupled to the laser. A transmitting optic is optically coupled to the multimode optical fiber for transmitting the beam into the measurement zone. The reflecting surface is configured to provide a Lambertian reflection. A receiving optic is positioned to receive the Lambertian reflection. Means are provided in operative association with the multimode transmitting fiber for averaging modal noise induced signal level variation of light propagating within the multimode transmitting fiber.


A method of monitoring blockage of a sight tube attached to a wall of a process chamber, the sight tube being operatively associated with a TDLAS optical head with a window between the sight tube and the TDLAS optical head. The method includes the steps of providing a photo sensor in the TDLAS optical head, the photo sensor being positioned to receive light emitted by a light emitting process within the process chamber. An emission signal produced by light emitted by the light emitting process within the process chamber being received by the photo sensor is monitored. A determination is made if the emission signal is degrading.


An embedded flight sensor system having a laser and one or more flight sensors in optical communication with the laser plus a data processing device in optical communication with the flight sensors. The flight sensors may be laser based optical components such as a fiber Bragg grating in combination with an optical detector, a spectroscopy grating and detector or an optical detector associated with catch optics. The parameters sensed by the flight sensors may be used to determine any flight parameter. Representative flight parameters include but are not limited to an airframe or external surface temperature, airstream velocity , combustion zone temperature, engine inlet temperature, a gas concentration or a shock front position.


A method of monitoring combustion properties in an interior of a furnace is described. A beam of light is projected through a pitch optic including a pitch collimating lens residing outside the boiler interior. The pitch collimating lens projects the beam through a penetration into the boiler interior. The beam of light projected by the pitch collimating lens is reflected from at least one in-furnace retro-reflector, and received with a catch optic substantially identical to the pitch optic residing outside the boiler interior. The pitch optic and the catch optic may be embodied in the same pitch/catch optic. The pitch collimating lens may also be steered toward another of the at least one in-furnace retro-reflectors. Combustion properties may be calculated for each retro-reflector based on retro-reflector zones within the furnace.


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