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...
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...
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 large...
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...
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 minimize...
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...
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...
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...
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...
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...
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...
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...
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...
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 titration...
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...
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...
We ask Greg:
What role do you see dynamic simulation playing in the future of developing the best fluidized bed gas reactor temperature control?
Greg's Response:
For gas reactants and a gas product, a pressure loop controls the material balance and provides the time available for...
We ask Greg:
What role do you see dynamic simulation playing in the future of developing the best multiphase reaction completion control?
Greg's Response:
For both batch and continuous reactors, reaction completion control seeks to provide a complete conversion of all reactants and...
We ask Greg:
What role do you see dynamic simulation playing in the future of developing the best liquid single phase continuous reactor composition control?
Greg's Response:
For reactions that are all in one phase (gas, liquid, or solid), inventory control (pressure or level control) cannot...
We ask Greg:
What role do you see dynamic simulation playing in the future of developing the best liquid single phase continuous reactor temperature control?
Greg's Response:
Temperature loops control the energy balance and the reaction rate through the Arrhenius equation. A cascade...
We ask Greg:
What role do you see dynamic simulation playing in the future of developing the best Flow Measurement Specifications?
Greg's Response:
Lack of recognition of the adverse effects of changes in process stream composition and operating conditions, upstream and downstream piping, and...
We ask Greg:
What role do you see dynamic simulation playing in the future of developing the best Temperature Measurement Specifications?
Greg's Response:
Process efficiency and capacity are often determined by a temperature control loop performance’s effect on the formation and...
We ask Greg:
What role do you see dynamic simulation playing in the future of adaptive pH Control?
Greg's Response:
In my 50+ year career in process automation, dynamic first principle simulations have played a more extensive and critical role in pH system design than any other process...
We ask Greg:
What role do you see dynamic simulation playing in defining the best Control Valve Specifications?
Greg's Response:
The biggest problem facing nearly all control loops stems from control valve specifications not requiring the control valve internal closure member to actually move...
