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

How many types of breakdown are possible in dielectrics, The following thre...

The following three types of breakdown are possible in Dielectrics: (a) Electrothermal Breakdown - This is caused by the heat produced because of the dielectric loss which is

Explain epitaxial growth, Explain Epitaxial Growth Epitaxial Growth ...

Explain Epitaxial Growth Epitaxial Growth - Refers to the growing of a crystal using one more crystal as the substrate, like that the atomic arrangement is continuous across

Refractoriness, Refractoriness: It indicates the capacity of a material to...

Refractoriness: It indicates the capacity of a material to withstand heat without appreciable deformation or softening under particular operating conditions and is measured as the

Explain projection printing, Projection Printing Projection printing, k...

Projection Printing Projection printing, keep away from mask damage entirely. An image of the patterns on the mask is projected onto the resist-coated wafer, which are many cen

What are extrusion applications, What are its applications? (i)   Direc...

What are its applications? (i)   Direct extrusion: The billet is placed in a container and forced by the die through a piston.  (ii)    Indirect extrusion: The extruded part

Solid fuels, Advantages and disadvantage of solid fuels

Advantages and disadvantage of solid fuels

Monolith reactor, Your first assessment will cover the design of a monolith...

Your first assessment will cover the design of a monolith reactor for the VOCs removal. Therefore, you are asked to do the following: 1. Choose a specific VOC; 2. Search for the

Saponification value of oil, The importance of oil acid and base titration...

The importance of oil acid and base titration in the saponification value of oil

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