Using portable optical oxygen analysers in power plants

Trends in the Power Industry have generated pressure and challenges on the instrumentation technology in the plant. The recent availability of new luminescent technology for dissolved oxygen (DO2) measurement provides answers to these requirements.

HACH LANGE has produced a report which describes the different scenarios of use and the associated benefits when the optical LDO technology and portability are put together. This is a brief summary.

Trends and challenges in the power industry
Before talking about the oxygen analysis it make sense to identify all trends and challenges driving instrumentation in the power industry.

The last decade has seen increased pressure on cost reduction together with other challenges leading to several consequences:

• Maintenance and service personnel reduction leading to optimisation of the different tasks and to decrease service and calibration time on all analysers in the plant.
• Less formal chemical training and knowledge applied in task supervision and instrument operation.
• Outsourcing of instrumentation services requiring the need for devices with less complexity and easier service operations.
• Extension of the operating lifetime of the plant equipment, challenging the entire steam and water analytic system in terms of performance and reliability.
• Peak power plants, running only during high demand periods with a large oxygen level variability between them, leading to more frequent calibration and service operations for the oxygen measuring devices.

How to use a portable oxygen analyser in the plant?
There are various scenarios for the use of a portable oxygen analyser in the plant. Combining the flexibility of a portable monitor with the strengths of the LDO provide new opportunities:

• As a validation tool
• On-line calibration
• Troubleshooting the process
• Troubleshooting on-line analysers
• As a backup unit

How does the Orbisphere 3100 meet the challenges of the Power Industry?
The combination of the LDO technology integrated in a portable device provides the right answers to instrumentation challenges in the Power Industry:

• Pressure on costs is covered by two main features. The device can be used for a wide range of applications such as validation, calibration, troubleshooting and as a backup unit. The solid state sensor requires no maintenance for up to three years and the device requires no 'babysitting' time when waiting for quick measurement results.
• Complexity is reduced by the high level of ergonomics of the unit with a bright touch screen and different tools and modes of use from spot measurements to a graphic view. The operator can concentrate his attention on data analysis.
• Extension of the plant operation lifetime requirement is supported by a better continuous monitoring of the corrosion source, by keeping the on-line oxygen loops at peak performance. This is the direct consequence of the LDO sensor short response time. With an EC sensor, going straight from a stand-by state to accurate reading may take more than 15 minutes. With the LDO it takes no more than 3 minutes to get the result, even if the analyser has not been used for many weeks. Validating or calibrating 10 on-line oxygen loops with a portable device has never been so quick and accurate.

To request a full copy of this report, please email sarah.blayds@hach-lange.co.uk