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

Water softening, What is phosphate conditioning in water softening?

What is phosphate conditioning in water softening?

Order of reaction, on doubling the concentration of reactant,the rate of re...

on doubling the concentration of reactant,the rate of reaction triples.what is the order of reaction?

Heat engine, derive an equation for efficiency of heat engine

derive an equation for efficiency of heat engine

Homework, Water from a supply having a total head of 100 ft is used in the ...

Water from a supply having a total head of 100 ft is used in the jet of an ejector in order to lift 10 ft3/s of water from another source (at a lower level) that has a total head o

Calculate the flow rate of bread produced, Question:1 (a) A flowchart o...

Question:1 (a) A flowchart of a continuous steady state two-unit separation process is shown below (Figure 1.1). Each stream contains two components, x and y, in different prop

Edta method, structure of EDTA and estimation of hardness of water by Edta ...

structure of EDTA and estimation of hardness of water by Edta method

Linear alkyl benzene, Linear Alkyl benzene (LAB) is produced by the alkylat...

Linear Alkyl benzene (LAB) is produced by the alkylation of benzene with olefins (assuming all dodecane). Raw maw materials: Kerosene and benzene. The chemical plant design comp

Water Treatment, Among phosphate and calgon methods, which one would be the...

Among phosphate and calgon methods, which one would be the best option for internal conditioning

Introduction to aspects of electrical maintenance, INTRODUCTION : Earlier ...

INTRODUCTION : Earlier in this course you have read about the requirements of laboratories. You also know that these requirements can be for consumable and non consumable nature

Material and energy balances, Wet air containing 4.0 mole% water vapor at 7...

Wet air containing 4.0 mole% water vapor at 76°F and 14.8 psia is passed through a column of calcium chloride pellets. The pellets absorb 97% of the water and none of the other con

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