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

Distinguish between intrinsic and extrinsic semiconductor, Distinguish betw...

Distinguish between intrinsic and extrinsic semiconductor. In intrinsic semiconductors, the conduction is because of the intrinsic processes characteristics of the crystal, wit

Matlab, how to solve partial differential equation using matlab and also di...

how to solve partial differential equation using matlab and also discreteing the pdf in matlab

.paint production, what is the effect of surfactant in paint

what is the effect of surfactant in paint

Leak test in hydrocracking plant, how to perform a leak test with nitrogen ...

how to perform a leak test with nitrogen in a hydrocracking plant in Russia

What do you understand by wet bulb globe temperature, What do you understan...

What do you understand by Wet bulb Globe temperature? Wet bulb globe temperature index is used to measure the sultriness of environment. Sultriness is calculated on the basis o

Explain soft magnetic materials, Soft magnetic materials  Soft magnetic...

Soft magnetic materials  Soft magnetic materials are majorly utilized in those applications in which the soft material has to amplify the flux occured by the electrical current

Free electron theory of metals, Free Electron theory of metals This the...

Free Electron theory of metals This theory tells that, metals conduct electricity due to the presence of free electrons in it. The outermost shells of metal atoms will be loose

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