Process control, Chemical Engineering

Assignment Help:

1.      In the system shown schematically below, water is supplied to a spray nozzle by a gear pump with a constant output of 20 US gpm. The flow rate of water discharged through the nozzle is controlled by manipulating the flow of water re-circulated around the pump using a proportional-plus-integral controller. The set point of the controller is normally 14 US gpm but can vary between 9 and 18 US gpm. The flow sensor has a range of 0-20 US gpm and responds instantaneously to flow variations. The control valve has a CV of 3 US gpm/psi1/2, a time constant of 2 seconds, a linear installed characteristic and is current-to-close.

(a) What should be the action of She controller (reverse or direct)? Why?

(b) Would it be better to eliminate the recirculation loop and install the control valve immediately downstream of the pump? Why?

(c) If the pump discharge pressure is 100 psig when the control valve is closed, show that the flow rate across the nozzle is 8 US gpm when the control valve is wide open,

Notes: The valve and nozzle are the only significant flow resistances in this system. You may also assume that the pump suction port and the spray leaving the nozzle are at atmospheric pressure. The nozzle behaves as an orifice.

(d) What are the outputs of the controller and flow transmitter (in %) when the set point is 12 US gpm and steady-state has been achieved?

148_Process Control.png


Related Discussions:- Process control

Heat transfer coefficient for the forced convection , A) A horizontal tube ...

A) A horizontal tube having a 1.25 cm outside diameter is submerged in a water 1 atm and 100 oC. Determine the heat flux for the surface temperature of (a) 540 o C, (b) 650 o C,

What is density of energy states, What is density of energy states? The...

What is density of energy states? The density of states (DOS) of a system explains the number of states at each energy level that are available to be get. A high DOS at a speci

Derive the ultimate primary controller gain, Consider the cascade loop as s...

Consider the cascade loop as shown below: i)   Specify the inner-loop gain such that the damping coefficient of the closed loop is equal to 0.4 ii)  Derive the ultimate

Explain with sketch the process of "forging", Explain with sketch the proce...

Explain with sketch the process of "forging". Forging is the process by which metal is heated and is shaped by plastic deformation by suitably applying compressive force. Gener

#Healthcare Statistics and Research, AskAs your final task (Key Assignment)...

AskAs your final task (Key Assignment), you will choose a topic in health care (e.g. cardiovascular issues, obesity, or cancer) and analyze it. Then, integrate all of the steps and

Sketch their bode plots and compare with the matlab figures, 1. Consider th...

1. Consider the previous heat exchanger.  Tune a proportional controller for a)  GM = 2; PM = 45 degrees and c)  MPH (maximum peak height) occurs at 2 dB (provides a z of ~ 0.4).

Molarity, WHATS THE MOLARITY OF SEAWATER

WHATS THE MOLARITY OF SEAWATER

Mass transfer, a. Explain the problems of flooding and channeling in packed...

a. Explain the problems of flooding and channeling in packed towertion..

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd