pumps & compressor

7/24/2019 Pumps & Compressor

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Pumps

Pumps are used to move liquid from a low pressure orlow elevation to higher pressure or elevation.

Two types of pumps generally in oil industry

Centrifugal pumps: Are recommended to use where

large volume at lesser pressure are required. Higherpressure can also be achieved by multistage

centrifugal pump.

!eciprocating pumps: Are recommended to use wherehigh discharge pressure and low flow rate are required


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Centrifugal !eciprocating

"low is completely steady #o output limit. High head obtained with

multistage at high speed

with large output. !ange $%%% to &%%% rpm 'irect coupling with motor

or engine. (ess efficiency when )*H

is low. ) depends on H. (ow capital +

maintenance cost

"low is more or lesspulsating.

,utput rarely e-ceeds%% m&*hr.

High head obtainedefficiently at low speed. !ange $%% to &%%rpm !eduction gear required. /fficiency is very high. ) is independent of H. high capital +

maintenance cost


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Centrifugal Pump

Centrifugal pump imparts velocity to a liquid. Thisvelocity change into pressure energy. Head develop isappro- equal to velocity energy.

H 0 1.*g2 where H is head in feet2 g is &. ft*sec..

This velocity can be calculated by 1 0 !P3 4 '*5

The static head corresponding to any pressure isdependent on the weight of liquid by the formula

Head in feet 0 head in psi - .&$* 6p.7r.

6tatic 6uction left : when the source of supply is belowthe centre line of pump. 1ertical distance in feet from thecentre line of pump to the top level of suction reservoir.


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Static suction head:when the source of supply is above

the centre line of pump. 1ertical distance in feet from thecentre line of pump to the top level of suction reservoir. Static discharge head: is the vertical distance in feet

from between the pump centerline and the top liquid levelin discharge reservoir.

Total static head: 1ertical distance in feet from the toplevel of suction reservoir to the top liquid level indischarge reservoir.

"riction head: head required to overcome resistance toflow in pipes + fittings.

1elocity head: head necessary to accelerate the fluid +calculated as hv 0 v *g.


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Total 'ynamic 6uction (ift 8hs9: 6tatic suction lift minus velocity head

at suction flange plus total friction head in the suction line.

Total 'ynamic 6uction Head 8hs9: 6tatic suction head plus velocityhead at suction flange minus total friction head in the suction line.

Total 'ynamic 'ischarge Head 8hd9: 6tatic discharge head plus

velocity head at discharge flange plus total friction head in the

discharge line.

Total 'ynamic Head 8T'H9 T'H 0 hd hs8with a suction lift9

T'H 0 hd hs8with a suction head9

Capacity : ) is normally e-pressed gpm + is directly related to the

velocity of flow and area of the pipe.

) 0 A 4 1 or 1 0 )*A


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;

Hydraulic Horsepower 8HHP9:% - @ #P6H : Total suction head in feet absolute at suction

nole minus the vapour pressure of the liquid in feetabsolute or is defined as the net pressure above thevapour pressure of the liquid being pumped. #P6Havailable e-ceeds the #P6H required by at least & to Bfeet


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Pump siing formulas

Head in feet 0 head in psi - .&$* 6p.7r

HHP of centrifugal Pump

0 gpm - head in ft - 6p.7r*&5>%

HHP of reciprocating Pump

0 gpm - psi * $$D

?HP 0 HHP * /fficiency

/lect HP input to motor 0 Pump ?HP* @

E< input to motor 0 Pump ?HP - .DB * @

Affinity (aws : These laws are the mathematicalrelationship between variables for centrifugal pump

performance. with impeller dia constant. )$*).0 #$*#.

H$*H.0 8#$*#.9. ?HP$*?HP.0 8#$*#.9&


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Problems

An oil of 6p. 7r .FB is required to transport froman underground tan= &%G deep from the pumpsuction to an uphill tan= at $&%G high. A pumpoperating at %%% rpm having an impeller dia $delivering at rate of &%% gpm is required toinstall. Calculate the ?HP of the pump2 thefriction losses along the pipes and fittings is D%psi. The pump is assumed to be >BI efficient.

Jf a pump delivers &B% gpm at $%% rpm.


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!eciprocating Pumps

Jn this pump energy is added to the fluid intermittently by

moving one or more boundaries linearly with a piston2 plungeror diaphragm.

Jf the liquid is pumped during movement in one direction it is

classified as single acting.

Jf the liquid is pumped during movement in both direction it isclassified as double acting.

These pumps are also classified by the no. of cylinders as

simple-2 duple-2 triple- or quantaple- etc.

#P6H available must e-ceeds the #P6H requird.

Jn case low #P6H application centrifugal pumps are used as

a charge pump to feed the suction of recipesL.


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Pulsation dampeners are used at suction and discharge

of pump the minimie pulsation2 piping vibration and to

reduce pump maintenance cost.

Pressure relief valves must be installed at discharge and

suction.

6wing type chec= valve 8#!19 to be installed at pump

discharge to avoid flow reversal and to reduce pulsation.

A cone type strainer to be installed at pump suction.


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C,3P!/66,!

The function of a compressor is to ta=e adefinite quantity of fluid 8a gas or air9 and

deliver it at a required higher pressure.

Compressors are used for compressiblefluids where as pumps are used for non

compressible fluids


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TYPES OF COMPRESSORS

Centrifugal Compressors

!eciprocating Compressors

6crew Compressors


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GENERAL APPLICATION

Centriugal Co!"ressors:

High mass rate of flow and low pressureratios.

Reci"rocating Co!"ressors:

(ow mass rate of flow and high pressureratios.


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Centriugal Co!"ressors

A centrifugal compressor consists of an impeller

with a series of curved radial vanes. Air is drawn

in2 through the impeller eye and is whirledaround at higher speeds by the vanes on the

impeller as the impeller rotates at high rotational

speed.


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RECIPROCATING COMPRESSORS

A reciprocating compressor is one which

increases the out let pressure of gas*air by

the reciprocating movement of piston.

!ation of discharge pressure + suction

pressure is called compression ratio.

Jn production facilities mostly pac=aged

type reciprocating are used.


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Component of Compressors

Compressor Prime mover

6crubbers

6uction + discharge pulsation bottles Coolers

Control panel

Control valves2 safety devices and

instrumentation


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,P/!ATJ#7 CMC(/

#$ Suction %al%e o"ens and gas isdra&n into the c'linder (# ) *+$

*$ Suction %al%e closes and gasco!"ression ,egins (* ) -+$

-$ .ischarge %al%e o"ens and theco!"ressed gas is dischargedro! the c'linder (- ) /+$

/$ .ischarge %al%e closes$ A ga"is sho&n in this diagra!

,et&een 0ero %olu!e and the%olu!e at "osition / &hich isclearance %olu!e in thec'linder$ ( / ) #+$


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S&e"t 1olu!e6wept volume is the volume swept by acompressor piston during a complete stro=e.

6wept volume is e-pressed in cubic inches andcalculated as follows:

Head /nd 0 Area Piston 8in.9 N 6tro=e 8in9Cran= /nd 0 8Area Piston 8in.9 Area !od 8in.99 N 6tro=e

8in9Total 0 O - Area Piston 8in.9 Area !od 8in.9 N 6tro=e8in9


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Piston .is"lace!ent

Piston displacement is e-pressed in cubic feet perminute and is the product of the swept volumeandcompressor speed in revolutions per minute. Thefollowing formula would be used to calculate thedisplacement of a cylinderQ

Piston .is"lace!ent (CFM+2 S&e"t 1olu!e(cu$ !+ 3 RPM

#4*5
http://g/Ariel%20Application%20ManualarieldbSwept_Volume.htmhttp://g/Ariel%20Application%20ManualarieldbSwept_Volume.htm


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(ubrication 6ystem

Compressor moving parts generate heat

due to friction.

"orce feed lubrication can minimie

friction + =eep the comp cool.

Piston2 piston rod Pac=ing2 crosshead

sleepers2 cran=shaft2 main and rod

bearings are lubricated

pumps & compressor

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