Emerson gas analysis contributes to power plant efficiency in South Wales

Emerson gas analysis contributes to power plant efficiency in South Wales
Rosemount Analytical oxygen sensors also increase safety and reduce maintenance requirements at npower Cogen plant

AUSTIN, TEXAS (February 22, 2007) - Rosemount Analytical flue gas analysis products from Emerson Process Management are helping to maintain efficient operations at the major RWE npower Combined Heat and Power (CHP) plant in Barry, South Wales. This npower Cogen plant supplies electricity, steam and treated process water to the adjacent Dow Corning manufacturing facility.

Close monitoring by the Rosemount Analytical Oxymitter of the flue gas oxygen levels is helping to maintain an overall efficiency rate of about 75 percent for the CHP plant. This means the plant uses substantially less fuel than conventional methods for generating heat and power. This efficiency prompted the UK Department for Environment, Food and Rural Affairs to consider the plant a “Good Quality CHP.”

The 28-MW of generating capacity is developed from two 6.5-MW Tornado gas turbines and a 15-MW Thermodyn steam turbine. Multiple high pressure waste heat recovery boilers and low pressure boilers also supply up to 250 tons per hour of steam capacity to the Dow Corning site.

Rosemount Analytical instrumentation has been well established at the plant, particularly for monitoring the boiler and process water treatment systems. After recent problems with the existing flue gas analyzer equipment, RWE npower installed a Rosemount Analytical Oxymitter 4000 unit on trial. This zirconium-oxide-based oxygen transmitter is designed to be directly mounted into high temperature flues. Its gas analysis measurements are used to fine tune the burner air/fuel ratios for maximum efficiency and reduced NOx emissions. Following the successful completion of this trial, the plant installed further units.

The Oxymitter 4000 appealed to npower Cogen because its sensor mounts directly into the flue gas duct. This eliminates the need for a sampling system and avoids the resulting operation difficulties and maintenance.

Also, the Oxymitter 4000 is available with split architecture. The high-temperature-tolerant probe is mounted directly into the duct and the associated operator and display electronics can be installed up to 60 meters away at ground level, enabling easy access. Operators no longer have to climb up through the plant to reach the flue gas head unit to make adjustments or to check the probe. This eliminates the difficult working conditions and significantly decreases the time spent during inspections and recalibrations.

Paul Gardner, Site Engineer responsible for npower Cogen instrumentation, is pleased with the improved accessibility: “It is far more convenient, and safer, not to have to send engineers right up to the head unit, where access is difficult and scaffolding is required to carry out the work. The Oxymitter local operator interface gives us a display of flue gas oxygen level and temperature, and with the sealed push buttons, we can carry out any calibration routines needed on the sensor from ground level.”

The Rosemount Analytical Oxymitter’s on-line diagnostic determines when calibration is needed and signals a warning on the ground-level display. This diagnostic routine automatically triggers the sensor monitoring electronics to take an impedance measurement of the cell to detect any drift or contamination. Any unusual readings trigger a warning on the local operator interface and suggest a recalibration.

The utilization of Rosemount Analytical flue gas analysis products at the CHP plant coincided with a major expansion of the Barry site in the late 1990s, which involved a £38 million investment by RWE npower. Dow Corning also invested £200 million at the time to make its site one of the most advanced silicon-based materials manufacturing facilities in the world. The Dow Corning facility now covers 160 acres and employs approximately 600 people.

About Emerson Process Management
Emerson Process Management, an Emerson business, is a leader in helping businesses automate their production, processing and distribution in the chemical, oil and gas, refining, pulp and paper, power, water and wastewater treatment, food and beverage, and other industries. A division of Emerson, Rosemount Analytical includes a gas division that offers a complete line of process, combustion and environmental analyzers for the power, chemical and refining industries. The best-in-class technology and expertise of Rosemount Analytical plays a key role in the Emerson mission of combining superior products and technology with industry-specific engineering, consulting, project management and maintenance services. Emerson brands include PlantWeb, Fisher, Micro Motion, Rosemount, Mobrey, Daniel, Bristol, DeltaV, Ovation, and AMS Suite.

About Emerson
Emerson, based in St. Louis, is a global leader in bringing technology and engineering together to provide innovative solutions to customers through its network power, process management, industrial automation, climate technologies, and appliance and tools businesses. Sales in fiscal 2006 were $20.1 billion.

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