We ask Greg:
What role do you see dynamic simulation playing in the future of best understanding of compressor open-loop backup?
Greg's Response:
Even a fast feedback controller is unable to get a compressor out of severe surge because of the huge jumps in flow. What is needed is an open-lo
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We ask Greg:
What role do you see dynamic simulation playing in the future of best understanding of compressor surge control?
Greg's Response:
The surge controller is a suction low controller with a remote set point that is parallel to the surge curve. Not only is surge prevented for all po
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We ask Greg:
What role do you see dynamic simulation playing in the future of best understanding of compressor surge oscillations?
Greg's Response:
Equations have been developed to show the compressor map to the left of the surge point not commonly known that is the key to understanding the
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We ask Greg:
What role do you see dynamic simulation playing in the future of best distillation column temperature control tray?
Greg's Response:
Process simulations or plant tests can be run to determine the tray with the largest and most symmetrical (linear) response to a change in the sp
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We ask Greg:
What role do you see dynamic simulation playing in the future of best distillation column temperature controller tuning?
Greg's Response:
Dynamic simulations running faster than real time are key to ensuring the best column temperature controller tuning. Except for high purity
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We ask Greg:
What role do you see dynamic simulation playing in the future of best distillation column temperature control strategy?
Greg's Response:
Dynamic simulations running faster than real time are key to ensuring the best column temperature control strategy. The manipulation of separ
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We ask Greg:
What role do you see dynamic simulation playing in the future of best distillation column pressure control?
Greg's Response:
Dynamic simulations can be help ensure distillation column pressure does not cause instability from operation at the weep point or flood point. The opera
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We ask Greg:
What role do you see dynamic simulation playing in the future of best crystallizer temperature control?
Greg's Response:
Batch-operated stirred cooling crystallizers are the most common type in the industry, but they tend to yield poor quality, primarily due to the high cooling
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We ask Greg:
What role do you see dynamic simulation playing in the future of best dryer temperature control?
Greg's Response:
The basic loop arrangement for dryer temperature control would use cascade control of outlet temperature to set inlet temperature. However, a constant outlet temper
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We ask Greg:
What role do you see dynamic simulation playing in the future of best kiln and calciner temperature control?
Greg's Response:
In kilns and calciners, there are typically four zones. First is a drying zone of constant temperature, followed by a heating zone of rising temperature
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We ask Greg:
What role do you see dynamic simulation playing in the future of best vessel temperature control?
Greg's Response:
A vessel is defined here as storage, recycle, blend, or surge volume where there is no heat of reaction and no agitator. Fortunately, most vessel volumes are so la
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We ask Greg:
What role do you see dynamic simulation playing in the future of best heat exchanger temperature control?
Greg's Response:
Flows much lower than design causes a high process gain and high process deadtime that can lead to temperature oscillations and possible instability. Low v
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We ask Greg:
What role do you see dynamic simulation playing in the future of best temperature measurement installation?
Greg's Response:
Temperature RTD sensors should use 4 wires and TC sensors should use extension wires of same material as sensor with length as short as possible to minim
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We ask Greg:
What role do you see dynamic simulation playing in the future of best temperature measurement selection?
Greg's Response:
Temperature is often the most important of the common measurements because it is an indicator of process stream composition and product quality. Temperature
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We ask Greg:
What role do you see dynamic simulation playing in the future of best lime system design for pH control?
Greg's Response:
Lime feeders have a transportation delay that is proportional to the length of the feeder divided by its speed. This transportation delay may be several min
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We ask Greg:
What role do you see dynamic simulation playing in the future of best liquid reagent dilution for pH control?
Greg's Response:
A common misconception is that the slope of the titration curve and, therefore, the system sensitivity can be decreased by reagent dilution. Reagent di
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We ask Greg:
What role do you see dynamic simulation playing in the future of best liquid reagent delivery for pH control?
Greg's Response:
If the reagent pipeline is partially filled or empty or a dip tube is backfilled with process fluid, the regent delivery delay becomes the biggest sour
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We ask Greg:
What role do you see dynamic simulation playing in the future of best reagent selection for pH control?
Greg's Response:
For a reagent dose to be precise enough, the reagent’s logarithmic acid dissociation constant (pKa) should be close to the pH set point so that it tends to f
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We ask Greg:
What role do you see dynamic simulation playing in the future of best control valve deign for pH control?
Greg's Response:
Stick and slip generally occur together and have a common cause of friction in the actuator design, stem packing, and seating surfaces. Rotary valves with
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We ask Greg:
What role do you see dynamic simulation playing in the future of best static mixer use for pH control?
Greg's Response:
Static mixer have noisy pH measurements. Signal filtering can help but a downstream volume is needed to provide smoothing of pH oscillations that can be large
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We ask Greg:
What role do you see dynamic simulation playing in the future of best vessel design for pH control?
Greg's Response:
pH systems are extremely sensitive to the vessel design. A poor design can make good pH control impossible in nearly all systems despite the use of the most adva
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We ask Greg:
What role do you see dynamic simulation playing in the future of best titration curve critical for pH system design?
Greg's Response:
The titration curve is the most important piece of information for designing, commissioning, and troubleshooting pH control systems. Lab titrati
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We ask Greg:
What role do you see dynamic simulation playing in the future of best minimization of pH system cost?
Greg's Response:
Because of the pressure to minimize capital costs, a project may sell itself short on the number of stages required. The basic rule from the 1970s was that a w
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We ask Greg:
What role do you see dynamic simulation playing in the future of developing the best maximization of reactor production rate?
Greg's Response:
Production rate can be maximized by a valve position controller (VPC) monitoring coolant valve position. The VPC setpoint is the maxim
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