Accurate Multiphase Flow Measurement

Many industries, such as oil & gas production, require flow measurement for fluids with gas and liquid phases.

Emerson's Kevin Borden

In this quick 1:49 video, 5700 with Advanced Phase Measurement, Emerson’s Kevin Borden describes how advanced phase measurement (APM) technology provides multiphase Coriolis flow measurement for challenging gas or liquid applications. APM technology is available in the Micro Motion Model 5700 advanced field mount transmitter.

Kevin notes that this technology can provide accuracy of +/-3% for a gas void fraction up to 15%. The APM algorithm provides corrected mass and volumetric flow values when multiphase flow conditions are present. Gas void fraction is also calculated. Continue Reading

Automatic Gauging for Onshore Oil and Gas Small Lease Tanks

Emerson's Michael Machuca

Author: Michael Machuca

Manual tank gauging is very prevalent in onshore oil and gas facilities located in the United States. It is viewed as a low-cost, effective solution to manage tank inventory and custody transfer measurements. The API 18.1 standard governs the procedure for how these measurements are made, but there is increasing concern around accounting accuracy, production losses and safety. Operators are also looking reduce costs and increase cash flow by better managing tank transfers, logistics and inventory.

API-18.2-Custody-TransferUntil recently, the only other solution was to install an expensive lease automatic custody transfer (LACT) unit, which can be uneconomical on sites with low production volumes. To address this issue, the American Petroleum Institute (API) has released a new standard API MPMS Chapter 18.2, Custody Transfer of Crude Oil from Lease Tanks Using Alternative Measurement Methods, which allows for custody transfer of crude oil from lease tanks using alternative measurement methods. While there has been an existing standard API 3.1B for automated tank gauging for custody transfer measurement, this standard was designed for large storage tanks with requirements that are not practical and are not economical for small lease tanks.

The industry realized the benefits to a more automated method of measurement. Because of this need, API took up the responsibility to issue a new standard API 18.2 to address the unique requirements of small lease tanks in onshore oil & gas operations. API 18.2 now considers guided wave radar level measurement as an acceptable solution and references the exiting API 3.1B standard but with reduced accuracy requirements associated with API 18.1 that are that are more suitable for smaller tanks. Continue Reading

Guided Wave Radar Level Measurement in Vessel Bypass Chambers

Accurately measuring levels in vessels is important in many aspects—safety, efficiency, reliability and availability to name a few. Mechanical level measurement devices historically have been failure prone and have required regular maintenance.

Emerson’s Thomas Rundqvist

Guided wave radar (GWR) technology avoids the problems with associated with mechanical devices, but is affected by obstructions in the vessel such as agitators, heat exchangers and other structures. In a Control Engineering Europe article, Ensuring reliability and accuracy with GWR, Emerson’s Thomas Rundqvist describes how a separate bypass chamber combined with guided wave radar level measurement can be used successfully for these vessels.

GWR-Accuracy-ReliabilityHe opens highlighting some advantages that external chambers provide. This installation method:

…isolates the radar transmitter for maintenance purposes, which is desirable for applications involving high temperatures/pressures or hazardous liquids. A further advantage is that if there is turbulence in the vessel the chamber acts as a stilling well, providing a calmer, cleaner surface and helping to increase measurement reliability and robustness.

Sizing the chamber is important to accurately measure the level inside the vessel. Some factors affecting accuracy include:

…the chamber diameter, the size of the process connections between the chamber and the vessel, and the ambient conditions.

Differences in temperature, vapor condensation and liquid stratification can also cause differences in level between the chamber and vessel. Insulation and lagging can help to prevent these differences.

Thomas provides tips on how to size the chamber correctly. Continue Reading

Surge Relief for Oil and Gas Liquids Pipelines-Part 2

Emerson's Rossella Mimmi

Emerson's Dave Seiler

Authors: Rossella Mimmi and Dave Seiler

In part one of our series, Surge Relief for Oil and Gas Liquids Pipelines, we provided background on surge conditions in pipelines transporting liquids, their effects on pipelines and why these effects matter to pipeline operators.

We’ll conclude this two-part series with a closer look at ways to prevent surge, methods of protection, surge systems and the need for pipeline hydraulic analysis.

What can be done to prevent surge

Some design approach and considerations can help prevent surge pressure from happening:

  1. Complete computer modeling of pipeline profile during the design stage, to determine the effects of unsteady flow of liquids transmission in the pipelines
  2. Stage pumps shutdown sequence, in conjunction with the closing of main pipeline valves
  3. Linked ship/shore emergency shutdown (ESD—for loading and off-loading tankers): historically, if the tanker’s ESD valve shuts in, the pump continues to operate for a period of time after the valve closure, causing surge pressure conditions. A linked ESD system uses the initiation of ESD on board the tanker to trip the pumps. The ESD valve closure time allows the pipeline flow to decay. These systems must insure the transfer pump is shutdown first.
  4. Stage ESD or motor operated valve closure times; extending the valve closure time will help reducing the surge effect

Surge protection methods

Even if all the above actions can help, a proper surge system should always be in place. Continue Reading

Advanced Automation Drives Project and Operational Cost Certainty

Emerson's Chuck Miller

Author: Chuck Miller

One of the most transformational cost-reduction trends in the automation industry is the application of configurable I/O.

Based upon the projects standards premise, reduced installation and commissioning time – along with the inclusion of late stage project changes without cost – configurable I/O is a technology that is critical to the optimization of project execution strategies.

DeltaV-CHARMsHowever, not all configurable I/O offerings are equal. These technologies must support all types of I/O and wiring options. This includes built-in field termination assemblies, which eliminate traditional marshaling and provide for I/O that can be assigned to a number of controllers at any time during the design, installation, commissioning, or operational phase of a project.

In addition, implementing wireless technologies not only eliminates costs associated with engineering and installation, but also allows people to perform their job from anywhere. This will challenge us to overcome the traditional culture; driving the need for “smart applications” to provide field operations teams with the status of all assets and immediate access to all forms of intelligent technologies on phones, PDAs, and other mobile devices. This will ultimately allow field personnel to predict changes – in demand or operation – prior to the event occurring at the gas processing facility, avoiding process downtime and changes in product quality. Continue Reading