“How low can we go?” That was the question Mario Sanjuan asked. The CPSE Deely Station was performing well, but they wanted to bring NOx emissions even lower. They knew that lack of real-time furnace information was a limiting factor in reducing NOx.

Deely turned to ZoloBOSS™, the only instrument that can measure and map multiple constitu-ents directly in the heart of combustion. Feeding this data into NeuCo’s CombustionOpt® en-abled CPSE Deely to optimize more aggressively and more flexibly.

Measure with light
The ZoloBOSS uses tunable diode laser absorption spectroscopy to determine concentrations of multiple combustion constituents. The technology scans a laser across known absorption lines and compares the amount of light absorbed to the amount of light transmitted. Each measure-ment, and there are up to 10,000 of them per second, is its own calibration for dust, ash, turbu-lence, and alignment drift.

Designed for boilers
TDLAS is a proven technology that has been around for years, but Zolo Technologies is the first to apply it to the harsh boiler environment. To accomplish this feat we had to make sure that sen-sitive electronics were located far from the harsh boiler conditions. In addition, the measurement technique had to be robust enough to collect data in the boiler environment even as the boiler water walls grow and shrink.

Zolo at Deely
All lasers, detectors, and computers are housed safely in a relay room, over 1,000 feet from the measurement heads. Measurement paths at Deely are arranged in a 4 x 5 grid just below the bull-nose.  Each path measures all constituents simultaneously and the nine paths are measured se-quentially within three minutes. Each head is controlled by the control rack in the relay room and automatically aligns before each measurement. Nearly 7° of pitch and roll alignment adjustment in each head means that the paths remain aligned even as load changes.

During the commissioning stages we faced some challenges with our standard sight tube con-figuration. There was flame impingement into the sight tubes that caused many of the windows to break and allowed pop-corn ash to accumulate. To rectify this issue we installed longer, slot-ted sight tubes to allow the ash to fall out of the tube. This modification fixed both the window breakage and the popcorn ash issues.

Measure where it counts
The ZoloBOSS can be used on its own to provide combustion engineers and operators with what amounts to continuous constituent HVT probe mapping of their boilers. Our team wants to prove that integrating this data with NeuCo’s CombustionOpt will not only help a plant optimize, but also enable faster and tighter boiler control. Once optimized, the boiler should be able to main-tain that state even as conditions change. Data from the combustion zone is more accurate and immediate than back-pass data and should enable more responsive optimization. We’re already seeing reduced heat-rates and NOx at Deely. It’s exciting to see what Mario and his team will do next!