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

Look, when do the cell get alot of thing in there thing because am confuse ...

when do the cell get alot of thing in there thing because am confuse cause is alot of thing becaus is crazy

Introduction-study of design and features of a laboratory, INTRODUCTION : ...

INTRODUCTION : Here you were introduced to the essential features of a good laboratory. Since no two labs are alike, it is important to know the design and organisation of the lab

Valves, Describe different type of valves

Describe different type of valves

Spelling resistance, Spelling resistance: The breaking or cracking or peel...

Spelling resistance: The breaking or cracking or peeling off the refractory is known as spelling. A good refractory must show a good resistance to thermal spelling. Thermal spelli

Pour point and its significance, Pour point: Just as flashpoint when tempe...

Pour point: Just as flashpoint when temperature is further lowered below cloud point of certain temperature, oil becomes semi-solid and losses its flow characteristics. This point

¿, miunuman t Boston party

miunuman t Boston party

Rheology, why do frosting on cakes do not fall off

why do frosting on cakes do not fall off

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