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John Accardo |

How can Clamp-on Ultrasonic flow meters identify what product is flowing from outside the pipe?

Many petroleum pipelines flow multiple products such as diesel fuel, gasoline and jet fuel. Between each of these products lies an interface where the flow stream transitions from one product to another. Pipeline operating companies depend on instrumentation to indicate what fluid is in the pipe and when an interface occurs in order to manage the pipeline’s operations. For example, flow arriving at a terminal is stored by product type in specific storage tanks. By knowing when an interface arrives, a valve can be switched to route the new fluid to its respective tank. Certain additives (e.g., Drag Reduction Agent “DRA”) may only be injected for specific fluids. So, you can see that knowing what fluid is presently in the pipe is critical to proper operation of the pipeline. Using a non-intrusive instrument for this purpose adds another level of benefits, including low cost installation, no loss of pressure, no interruption of the DRA, and the ability to allow pig passage through the measurement point.

How can an instrument do all this without actually touching the product?
In a word, “Liquid Table”.  OK, so that’s 2 words. Actually, it’s fairly simple and it’s all based on sonic velocity. The Siemens SITRANS FUH1010 is designed primarily for hydrocarbon liquid measurement. These fluids “behave” in a very predictable manner; that is, their sonic velocity values change linearly relative to temperature and pressure and by the same “slope” factors across liquid types. The FUH1010 ultrasonic flow meter precisely measures the “actual” sonic velocity (called Vs) of the flowing liquid, as well as its temperature. Since we know the (Vs) slope factor for hydrocarbon liquids, the “measured” Vs can be corrected to a “standard” (base) value (typically 60 °F.) This temperature-corrected (normalized) sonic velocity is known as Liquident. By using Liquident, we level the playing field by eliminating the possibility of confusing one liquid with another due to temperature (and/or pressure) influences.  Now it’s a simple matter to identify the fluid; this is where the “Liquid Table” comes into play.

The FUH1010 clamp-on flow meter comes equipped with an integral liquid table, which is essentially a mini database of common hydrocarbon fuels (See Figure 1). Once the Liquident value has been determined, the table recognizes the matching Liquident, pinpointing (by name) the current liquid being measured. Besides the liquid’s name, its associated density (Sg) and Viscosity values at base temperature are also identified. This enables the FUH1010 to publish “live” data of the liquid name plus the liquid’s density (Sg, API, Kg/M3) and viscosity at “base” conditions, as well as computation of density and viscosity for “actual” pipeline operating conditions.

Besides product identification, the FUH1010 brings many additional benefits to the pipeline operator.

Product ID is only one small facet of the FUH1010’s capabilities. It is, after all, a high precision flow measurement instrument. Therefore, it includes many useful features to help you manage your pipeline’s operations, including:

  • standard volume correction of flow rate and total,
  • mass flow rate indication, interface detection,
  • low/high flow rate alarming, batching, and pig detection,
  • bi-directional flow measurement.
  • non-intrusive design, which allows no interruption of flow for installation or servicing

The FUH1010 clamp-on ultrasonic flow meter, through the use of its dynamic liquid table, provides a powerful tool for managing pipeline operations and intra-terminal flow management.

How can it help you more effectively operate your pipeline system?

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