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

Bakelite, Bakelite is a material based on the thermosetting phenol formald...

Bakelite is a material based on the thermosetting phenol formaldehyde resin. Produced by the reaction under heat and pressure of phenol (a toxic, colourless crystalline solid) and

Portland cement, describe layout of wet process for portland cement industr...

describe layout of wet process for portland cement industries ?

Aeration, all about aeration in water system

all about aeration in water system

Reaction between chloride ion and a primary carbocation, Which one of the  ...

Which one of the  following  statements  about  product  A is correct? It arose from a reaction between chloride ion and a primary carbocation It arose from a reaction

What is ionic bonding, Ionic  bonding. An ionic bond (or electrovalent...

Ionic  bonding. An ionic bond (or electrovalent bond) is a type of chemical bond that can often form among metal and non-metal ions (or polyatomic ions like as ammonium) throug

Polymers assignments, What are the applications of polymers in electrical a...

What are the applications of polymers in electrical and electronics industries>

Advantages and disadvantages of cold working, Advantages of cold working ...

Advantages of cold working (i)  No heat is needed. (ii)  Better surface finish is get. (iii)  Superior dimension control. (iv)  Improved strength and hardness properti

Fraction, what is the mole fraction of solute and solvent is equal to

what is the mole fraction of solute and solvent is equal to

#esterification, what do i do to eliminate odor from cowdung?

what do i do to eliminate odor from cowdung?

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