Feb 23, 2007

Emerson’s Technology Contributes to CHP Plant Efficiency in South Wales

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% for the CHP plant. This means the plant uses substantially less fuel than conventional methods for generating heat and power. This efficiency prompted the U.K. 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.

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, the 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 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.

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