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

Boiler troubles-scale and sludge formation, #question.dicuss brifely the bo...

#question.dicuss brifely the boiler troubles and their treatment

Mass and partial energy balance, Mass and Partial Energy Balance The p...

Mass and Partial Energy Balance The process flow diagram attached shows a very simplified approach to the production of Potash from Sylvinite ore. Conduct a mass balance and a

Porosity, Porosity: The property of the refractory brick is the ratio of i...

Porosity: The property of the refractory brick is the ratio of its pore volume to the total volume. The refractory material with high porosity is not preferred for furnace lining

Hardness control, how can i controll hardness in the boiler

how can i controll hardness in the boiler

Explain loss angle, Explain Loss Angle Loss Angle can be described a...

Explain Loss Angle Loss Angle can be described as the arc-tangent of the electrical dissipation factor.

Solid mensuration, #quehe two sides of a triangle are 17 cm and 28 cm long,...

#quehe two sides of a triangle are 17 cm and 28 cm long, and the length of the median drawn to the third side is equal to 19.5 cm. Find the distance from an endpoint of this median

Formox Process, Hi, my name is Luan Sousa, i am from Brazil and i am a chem...

Hi, my name is Luan Sousa, i am from Brazil and i am a chemical engineering student. I am developing a project of formox plant design and i would like to know about yields of conve

Internal conditioning of water, describe briefly any four internal conditio...

describe briefly any four internal conditioning methods

Acetic acid, the full reaction mechanism for production of acetic acid from...

the full reaction mechanism for production of acetic acid from feed of ethylene via wacker process with acetaldehyde as an intermediate

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