Laser-Based Moisture Analyzer for Hydrogen Recycle Gas Delivers Fast and Repeatable Readings

Getting timely and repeatable moisture measurements in the catalytic reformers of a refinery has always been problematic — until lately. The presence of harsh chemicals, particularly hydrochloric acid, is so destructive to the moisture analyzer probes that refineries have accepted their imminent failure to be a fact of life.

Yet, the need for getting reliable readings of moisture present in hydrogen recycle streams is critical enough to force refineries to install multiple sensors in this process stream, hoping that at least one will be operating properly. As a result, refineries are spending $10,000 - $20,000 and upwards for servicing and replacing damaged sensor probes.

“This continual cycle of high maintenance costs for conventional moisture sensor probes is primarily due the constant exposure of the probes to damaging chemicals in the stream they are sampling,” explains Al Kania, a representative of SpectraSensors, Inc. (San Dimas, CA) to the petrochemical industries. “Since moisture affects the life of the very costly catalysts used in producing aromatics, refineries have been forced to live with the outmoded moisture analysis technology that is both unreliable and expensive.”

That widespread problem is now being solved through the use of a laser-based technology that is accurate, fast and virtually maintenance-free. Originally developed by NASA for such projects as the Mars Lunar Lander, the technology was spun-off commercially with the formation of SpectraSensors, which now manufactures and markets the laser based moisture analyzer.

“This new technology is completely unique because it does not expose the laser, which measures moisture, to the harsh chemicals in the stream,” Kania explains. “Instead, this SpectraSensors analyzer is designed to extract samples out of the process into an isolated sample cell, where it is analyzed. Because the laser is located behind a protective window, the harmful compounds in the stream — those that compromise a conventional sensor — have no damaging effect.”

Kania points out that the laser-based technology has become the new standard in moisture analysis for natural gas pipelines, where moisture content can be very costly in terms of lost revenue and damage to pipelines.

“Other than maintenance-free performance, the most important benefits to oil refineries using SpectraSensors moisture analyzers are response time and repeatability,” adds Kania. “It usually takes conventional sensor probes a long time to ‘see’ a spike of moisture concentration in the line. That problem of critical response time does not occur with the laser-based sensors, which provides instantaneous results.”

The other vital factor, repeatability, is assured with the SpectraSensors laser-based moisture analyzer, enhancing process control. Good repeatability is possible with tunable laser spectroscopy because the analyte (the gas that is undergoing analysis) cannot damage or physically change the sensor components.

SpectraSensors, Inc. headquartered in San Dimas, California, was incorporated in 1999, as a technology spin-off of the NASA/Caltech Jet Propulsion Laboratory. The company is a leading manufacturer of optically based gas sensors for the industrial process and environmental monitoring markets. Typical applications include non-contact measurement of moisture, carbon dioxide, and other corrosives in natural gas pipelines (Energy Market), industrial process monitoring (Petrochemical), and airborne water vapor and other atmospheric measurements from commercial aircraft for the U.S. and International Weather Services (Atmospheric).

For more information contact: Sam Miller, Director of Marketing — Energy Tel: (909) 542-0394 x228 Fax: 909-542-0402 Email:smiller@spectrasensors.com SpectraSensors, Inc. 972 North Amelia Avenue, San Dimas, CA 91773 www.spectrasensors.com