Category Archive: Unit Operation Control

Aug
13

Emerson Exchange – Meet the Expert Session

This year Emerson Exchange will be held October 8-12, 2012 – Hilton Anaheim in Anaheim, California.  A number of meet the expert sessions are scheduled for the last day of the conference, Friday, October 12th . Willy Worjsznis and I will host one meet the expert session in which we will give an overview of …

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Aug
06

Advanced Control Foundation – Coming Soon

Advanced Control Foundation

Many of the advanced control products available in the DeltaV control system can be traced to an advanced control research and development program established within Emerson Process Management in the early 1990s. The ISA book Advanced Control Unleashed – Plant Performance Management for Optimum Benefit, published in 2003, included examples based on advanced control software …

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Jul
30

Boot Camp for New Employees

BookOutline

Courses required for an engineering degree are designed to provide the student with a sound technical foundation for work in industry. However, in most cases these courses do not address the terminology and common practices that an engineer must know to design, implement, checkout and commission a process control system. Universities can help bridge this …

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Feb
13

Monitoring Turbine and Compressor Operation

Compressor Efficiency

In January I posted a series of four (4) blogs that addressed the implement of an on-line compressor efficiency calculation. The example for this series was a compressor for a refrigeration system that used R134a refrigerant. If you have a similar compressor application in your plant then the information provided in these blogs may act …

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Feb
06

Teaching the 9025 Class – Costa Rica

Costa Rica  - San Jose

The week of January 8th, 2012 I traveled to our office in Costa Rica to teach the 9025 class. This class was created last year by Emerson’s education department to provide training on the basics of process control and instrumentation. The lecture material and student workshops included in the class are based on the book …

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Jan
30

Centrifugal Compressor Efficiency – Part 4

CompleteEff

Part 1 of the centrifugal compressor efficiency series addressed the measurements and parameters that must be calculated to determine compressor efficiency. In Part 2-3 of this series we examined one way of calculating the enthalpy and entropy of the gas stream at the compressor suction and discharge and isentropic enthalpy for the refrigerant R134a. Once …

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Jan
26

Compressor Surge and Stall Detection and Prevention

A compressor going into stall is like jumping off a cliff with a bungee cord. If the bungee cord has no losses to dampen the oscillation, we have something akin to surge. A 0.5% drop in efficiency can occur for each surge cycle. Several surge cycles can occur due to delays and lags in high …

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Jan
23

Centrifugal Compressor Efficiency – Part 3

Entropy R134a

Part 1 of the centrifugal compressor efficiency series addressed the measurements and parameters that are used to calculate compressor efficiency. In Part 2 of this series we examine how these measurements are used to calculate the enthalpy of the gas stream at the compressor suction and discharged for the refrigerant R134a. This calculation utilized bilinear …

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Jan
16

Centrifugal Compressor Efficiency – Part 2

R134a Thermodynamic Properties

As addressed in Part 1 of the centrifugal compressor efficiency series, the enthalpy of the gas stream at the compressor suction and discharge must be known to determine the compressor efficiency. Also, the isentropic enthalpy must be determined based on the gas stream entropy at the compressor suction and the compressor discharge pressure. These properties …

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Jan
09

Centrifugal Compressor Efficiency – Part 1

Measurements On-line Compressor Efficiency

Centrifugal compressors play an important role within the process industry. In some cases compressor capacity may determine the throughput of a plant. If a compressor is used for refrigeration then any variation in compressor operation may directly impact the temperature control in key unit operations such as flash vessels and exothermic reactors. Also, the compressor …

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