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

Chemical engineering thermodynamics 1, I want some lecture notes on propert...

I want some lecture notes on properties of pure substances, Ideal gas laws

EMERGENCY !!!, We have a lot of water plastic bottels that are being threw ...

We have a lot of water plastic bottels that are being threw and wasted , how can we use them in a onother way like making it into a fabric, or I need any topic for project that inv

Flash tank, a mixture of propane (125 lbmole, K = 2.056), n-butane (200 lbm...

a mixture of propane (125 lbmole, K = 2.056), n-butane (200 lbmole, K = 0.925), and n-pentane (175 lbmole, K=0.520), is at 200 psia and 200 F. determine the phase of the mixture?

Outlet water temperature, A shell-and-tube Heat exchanger with one shell ex...

A shell-and-tube Heat exchanger with one shell exceed and two tube passes si to be designed to condense 3900 kg/hr of steam at 1 atm. Steam may be suppose to enter the shell side a

Mass transfer operation, a. Explain the problems of flooding and channeling...

a. Explain the problems of flooding and channeling in packed tower

Production of chemicals from coal, Production of Chemicals from Coal C...

Production of Chemicals from Coal Coal has been considered a major component of U.S. energy reserves for a long time, and more recently it has become an important raw material

Characteristics that can affect the flow of bulk solids, What are the diffe...

What are the different characteristics that can affect the flow of bulk solids and how? The main characteristics which can affect flow of bulk solids are as below: > Moistu

Describe various properties of mica and transformer oil, Describe various p...

Describe various properties and applications of mica and transformer oil. Properties and uses of MICA Mica has a high dielectric strength and good chemical stability, making

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