Ways to Improve Plant Performance via Pressure Instrumentation

Embedded diagnostics in smart instrumentation has played a role in safer, more efficient and reliable plants for decades in the process industries. As the power of the microcontrollers at the heart of these intelligent devices grows, so do the reliability, accuracy and diagnostic coverage grow.

Pressure-Instrumentation-WhitepaperA new whitepaper, 7 Ways to Improve Productivity and Process Operations with Pressure Instrumentation, provides practical examples of putting the accuracy, reliability, diagnostic coverage to effective use.

I’ll briefly share the seven ways and invite you to request a copy of the whitepaper. The first way is to use the diagnostic coverage to increase uptime. We shared one example how in an earlier post, Early Detection of Distillation Column Flooding Conditions.

The second way is to simplify process connections to improve reliability. Differential pressure (DP) flow and level measurement are great examples where this can be done. We discussed this in a post, Eliminating Temperature Effects in DP Level Measurement.

The third way is to eliminate heat tracing to increase accuracy and reduce costs. We described one way how in a post, Avoiding Cold Climate Measurement Challenges.

The fourth way is to easily and economically add measurement points to increase process insight. For many plants and production facilities the challenge and cost of running wires to add the measurement has been a limiting factor. As a result, measurement devices were minimized to what was needed to control the process. Wireless devices now make it possible to add measurements to improve energy usage, monitor rotating assets, and much more.

The fifth way is to compensate flow measurement to protect profits. Flow is a fundamental fiscal measurement in custody transfer applications. We highlighted this opportunity in a post, Assuring Accuracy in Fiscal Measurement and Custody Transfer.

The sixth way is to operate closer to set point to control for process variability. This was one of the points made in a recent webinar on blending operations for refiners. With extremely tight sulfur limits in transportation fuels, accurate and reliable measurements allow the blend recipes to move the process controls closer to the specification limits without exceeding the limits.

Stability-Specification

The final way described in the whitepaper was to have the ability to standardize on a common instrument platform to optimize budget. Standardization affects many areas including design, procurement, installation, commissioning as well as training and maintenance procedures.

Request the whitepaper for more detail on each of these ways and you can connect and interact with other pressure measurement experts in the Pressure group in the Emerson Exchange 365 community.

7 comments

  1. For the second way only 4-20 mA is mentioned for eliminating impulse piping and capillaries but it can of course also be achieved using fieldbus since FF is time-synchronized as explained in the post “Efficient Distillation Columns Require Accurate DP Measurements”
    http://www.emersonprocessxperts.com/2013/03/efficient-distillation-columns-require-accurate-dp-measurements/
    “If the devices are Foundation fieldbus-based, the communications are synchronized and accurate calculations can be performed by the control system.”
    Since leading pressure transmitters also contain an arithmetic function block the calculation can be done in one of the pressure transmitters itself to get a local reading; in both transmitters or in separate display; “virtual remote seals” if you will.

    The fourth way is the one that really strike a chord with me. There are so many “missing measurements” around the plant. See the post “Adding Missing Measurements in Refineries”
    http://www.emersonprocessxperts.com/2013/08/adding-missing-measurements-in-refineries/
    Wireless transmitters are a great way to cover these. There are all kinds of missing measurements. Pressure features in many applications, but there are also vibration, valve position, temperature, pH/ORP, conductivity, level, and flow etc. Many flow and level applications can be handled using pressure transmitters although wireless guided wave radar level transmitters are available. Pressure transmitters are now being deployed in applications beyond the P&ID such as filter and strainer/screen blocking/plugging, pump seal pressure, lube oil pressure, heat exchanger blocking, DP flow, fire protection system integrity, and replacing manual data collection rounds reading pressure gauges. There are many improvements that can be made once a WirelessHART gateway is in place in the plant unit. Many of these applications are related to improving equipment reliability while at the same time improving maintenance productivity as explained in this new article:
    Multi-parameter Condition Monitoring
    http://www.ceasiamag.com/2015/06/multi-parameter-condition-monitoring/

  2. Hey folks this is a great article about pressure instrumentation, I have a inquiry about the point 2 “Simplify process connections to improve reliability”, normally the orifice plates and pressure taps for flow transmitters are ubicated in a horizontal pipe located on a pipe rack, I mean on a tall point. The customers have been normally doing maintenance and routine checks on ground level, If the customer use compact assemblies for him mean that during the maintenance or routine check, he will need use a ladder or scaffold in order to make his activity. How can we discuss/justify with the customer this different transmitter’s location?

  3. Jim Cahill says:

    Hi Juan, Thanks for your question. I’m checking with a few of my friends who manage the Rosemount brand. Let me see what I can find out.

  4. Juan – The nice thing about using compact assemblies is that it reduces the number of leak points so you shouldn’t see as many leaks and thus shouldn’t have to inspect them as much. Ultimately this saves significantly on maintenance rounds thus helps with the justification.

  5. This is a good article…like it and thanks for sharing

  6. Hi I have one very basic question associated with subject topic, would appreciate if some one could help me with it:

    We are measuring DP (0.35 barg is alarm) across the sour water stripper through a DP transmitter with remote seals and capillary tubing. However this instrument was not working fine, we are now replacing it with Emerson ERS system with two similar transmitters 3051SAM type with range of (-1 to 10.35 barg), as per the catalog the accuracy of these two transmitters is 0.035% of span.

    Oper pressure = 1.75 barg
    design pressure = 5.5 barg
    DP alarm set point = 0.35 barg

    Now my question is how accurate would be my DP measurement? As the transmitters themselves are only 0.035 % of span which as per my calculation = 0.035 X (-1 to 10barg = 11) = +/-0.385

    Is it the correct calculation im doing?

    What is term range down? It is mentioned as 150:1

    Which is the most accurate type to measure DP across the columns/absorbers?

    Appreciate if some one can help me with my basic and stupid questions
    =

    I have following concerns

  7. Jim Cahill says:

    Hi Ali, Let me ask a few friends on our Rosemount DP measurement team and see what they say… thanks!

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