Process control, Chemical Engineering

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

Posted Date: 2/23/2013 1:00:34 AM | Location : United States

Related Discussions:- Process control, Assignment Help, Ask Question on Process control, Get Answer, Expert's Help, Process control Discussions

Write discussion on Process control
Your posts are moderated
Related Questions
hello, i am asad, frome bd. i need help..........

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

I need help with my project. for more information. email me

how do i stop flaring of iron and steel emission

manufacture process

What is meant by crystal imperfections? Crystalline solids have a very regular atomic structure: that is, the local positions of atoms with respect to each other are frequent a

Reactants Acrylonitrile and Dimethylamine to form product DMAPA i.e. Dimethylaminopropylamine. What is the specific consumption of reactants to produce 1mole of DMAPA

How chemilcal#..

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?