If safety is the bottom line for power plant operation, then economic efficiency is its lifeline for sustainable development. Modern ultra-supercritical units pursue ultimate thermal efficiency, meaning that precise control of every process parameter is crucial.
However, an easily underestimated "hidden risk"-static pressure error-is seriously threatening the quality of the control loop and quietly eroding power generation efficiency. This article will reveal how high static pressure transmitters, by overcoming this challenge, have become a core tool for improving unit economic efficiency.
PART.1: Static Pressure Error: A "Fatal Drift" in Accuracy Under High Pressure Environments
In conventional pressure measurement, we mainly focus on the accuracy and stability of transmitters. However, in the high-pressure environments of supercritical and ultra-supercritical units, a special challenge emerges: static pressure error. This refers to the undesirable drift of the transmitter's zero-point output value as the background static pressure of its system changes.
PART 2: High Static Pressure Transmitters: Suppressing Static Pressure Errors, Improving Process Control Quality, and Providing Economic Guarantee for Power Plants.
Modern power plants pursue maximum thermal efficiency. Even minute parameter deviations can directly lead to malfunctions in the control system, causing the boiler to deviate from its optimal combustion efficiency point, resulting in significant heat loss and increased costs.
- Achieving High-Precision Minimal Differential Pressure Measurement Under High Pressure Backgrounds
For example, measuring the main feedwater flow rate requires precise measurement of the differential pressure signal, which may only be tens of kilopascals, generated by the throttling device under a static pressure of 40 MPa. Ordinary transmitters will produce significant "static pressure error" (i.e., zero-point drift with changes in static pressure) under high static pressure.
High static pressure transmitters, through special design and compensation technology, control the static pressure error within an extremely small range (e.g., <±0.025% URL/1000 psi). This allows it to "see clearly" minute process changes even under extreme background pressures, providing accurate flow feedback for automatic feedwater control and water-fuel ratio coordinated control (CCS), thereby ensuring that the boiler operates at its optimal efficiency point.
- Supporting Advanced Control Strategies
In ultra-supercritical units, controlling the flow rates of the primary and secondary desuperheating water spray is like a "precision scalpel" for finely regulating the main steam and reheat steam temperatures. The desuperheating water is drawn from the high-pressure feedwater system, resulting in extremely high pressure, but the flow control requires extremely high sensitivity. Only high static pressure differential pressure transmitters can stably and accurately measure these small flow signals under this high-pressure environment, thereby achieving smooth switching between various modes such as subcritical, supercritical, and DC operation, and precise steam temperature control, directly affecting the unit's thermal efficiency and economy.
The ability to control static pressure error determines the baseline of measurement quality. High static pressure transmitters, with their superior accuracy, transform minute changes under extreme pressure into reliable data, providing a solid guarantee for the unit's economical operation and safeguarding every bit of thermal efficiency value.