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

Characteristics of ferro-electric materials, What are the chief characteris...

What are the chief characteristics of ferro-electric materials Ferroelectric materials have following characteristics: a)  They have a huge dielectric constant which is non-

Look, nerve cell reproduces

nerve cell reproduces

Mixing salt solutions, Mixing Salt Solutions You mix 195.0 gallons of ...

Mixing Salt Solutions You mix 195.0 gallons of a mixture containing 12.00 wt% NaCl (sodium chloride) and 88.00 wt% water (solution density = 1.0837 g/cm 3 ) with a V 2 -gallon

Temperature of the shield, Two parallel planes 1.2x1.2 are splited by a dis...

Two parallel planes 1.2x1.2 are splited by a distance of 1.2 m. the emissivity's of the planes are 0.4 and 0.6, and the temperature are 760 and 300 oC, correspondingly. A 1.2x1.2 r

Explain brazing and soldering, Brazing and Soldering - Both soldering and ...

Brazing and Soldering - Both soldering and brazing processes are useful for combination two dissimilar metals. Both brazing alloy and solder have lower melting points than the met

What is tie-line rule, What is tie-line rule? The tie-line rule is appl...

What is tie-line rule? The tie-line rule is applied to verify the compositions of two co-existing phases in a binary phase diagram. The tie line is a horizontal line drawn at t

Convection heat transfer, An enclosure haves Helium at a pressure of 1.3 at...

An enclosure haves Helium at a pressure of 1.3 atm and has two vertical heating surfaces, which are keeps at 80 and 20 oC respectively. The vertical surfaces are 40x40 cm and are s

Metallurgy, explain physical and chemical methods of extraction in detail?

explain physical and chemical methods of extraction in detail?

Homes, Ask questionbats #Minimum 100 words accepted#

Ask questionbats #Minimum 100 words accepted#

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