Fig. 3.1.4a

 

Fig. 3.1.4b 

 

Fig. 3.1.5

DISCHARGE PIPING

ISOLATION VALVE

NON RETURN VALVE

PRESSURE INDICATORPI

CONCENTRICREDUCER

ECCENTRICREDUCER

F.S.U

SUCTION PIPING

ISOLATION VALVE

'Y' TYPESTRAINER

DRAIN

PUMP CASTINGCL

COMPONENTS OF A TYPICAL PUMP SUCTIONAND DISCHARGE PIPING SYSTEM

ECC. REDUCER

DRAIN

TYPICAL SUCTION LINE SUPPORT

BYPASS LINE

FCV

BYPASS LINE

(ALT)

COOLER

ARRANGEMENT FOR MINIMUM FLOW FOR CENTRIFUGAL PUMP

USE OF ECCENTRIC REDUCERS ALLOWS

LARGER FLANGES ON VALVES TO CLEAR

ECCENTRIC REDUCERS AT PUMP CONNECTIONS

The complexity of piping system design, maintenance, and troubleshooting requires the process Engineers, the Maintenance Engineers and the Piping Engineers on the same Wavelength and work more closely together.

Fig. 3.1.6

The following general concepts apply for locating the heat exchangers.

a) Exchangers should be located adjacent to the related equipment., e.g. Reboilers should be located attached/

next to their respective towers, condensers should be located next to reflux drums close to tower.

b) Exchangers should be close to the other process equipment e.g. in case of draw off flow through an exchanger from a vessel/reactor bottom, the exchanger should be close to and under the vessel or reactor to have short pump suction lines. Overhead condenser shall be placed above the reactor to have minimum horizontal piping.

c) Exchangers connecting two equipment, one on shell side and the other on the tube side, located at a distance, should be placed where two streams meet,

and on that side of the yard where majority of related equipment is placed.

d) Exchangers between process equipment and the battery limit. e.g. product coolers, should be located near the battery limit to reduce pipe rum. e) Stack those exchangers which can be grouped

together to simplify piping and save plot space. f) Leave space and access around the exchanger flanges

and heads, and tube bundle cleaning/pulling space in front and in line with the shell.

  

g) While locating exchangers in a row, arrange the saddle to have more economical overall (lined up or combined) foundation / structure design. Further, travelling gantry can be provided in such case to handle a row of exchangers.

h) The heat exchanger shall be located in the equipment layout with respect to the fixed saddle and the

same is located closer to the head i) Outline the clearances and working space in the front

and around both ends of the exchanger to facilitate shell cover and tube bundle removal as well as maintenance and cleaning.

j) The channel end shall face the roadside for convenience of tube removal and the shell

cover the rack side.

The various clearances shall be as indicated in Fig. 3.3.1. All Dimensions are in mm

Fig. 3.3.1a

 

Fig. 3.3.1b

The basic principles adopted in the heat exchanger piping are:  a) The working spaces should be kept clear of any piping and accessories to facilitate channel, shell- cover and tube bundle removal, as well as maintenance and cleaning. b) Excessive piping strains on the exchanger nozzles from the actual weight of pipe and fittings and from forces of thermal expansion should be avoided. c) The piping shall be arranged in such a way that no

temporary support will be required for removing the channel and tube bundle.

d) Provide easily removable spool pieces, flanged elbows, break flanges, or short pipe runs to provide

adequate clearances for the operation of tube removal.

e) The pipe lines with valves and control valves should run along with access aisle close to the exchanger.

f) Pipe line connecting the exchanger with adjacent process equipment can run point to point just above

required head room. g) Steam lines connecting the header on the rack can

be arranged on either side of the exchanger h) Valve handles should be made accessible from the

grade and from access way. These access way should be used for arranging manifolds, control valves stations and instruments

i) To avoid condensate drainage toward exchanger, the preferred connection for steam lines is to the top of the header. However, there is nothing wrong in having a steam connection from the bottom of the header if

steam traps are placed at the low point j) The standard dimensions related to exchanger piping are given in sketch. These details are illustrated in Fig. 3.3.2.

 

Fig. 3.3.2a 

 

Fig. 3.3.2b

The basic types used in the chemical process industry are –  1)  Fixed tube-sheet Heat Exchange  2) `U’ Tube Heat Exchangers  3)  Floating Head type Exchangers  4)   Kettle type Heat Exchanger  

HEAT EXCHANGE NOMENCLATUREN-2 NOMENCLATURE OF HEAT EXCHANGER COMPONENTS

For the purpose of establishing standard terminology, Figure N-2 illustrates types of heat exchangers. Typical part and connections, for illustrative purposes only, are numbered for identification table N-2

Table N-21.    Stationary Head –Channel2.    Stationary Head – Bonnet3.    Stationary Head Flange-Channel or Bonnet4.    Channel Cover

5.   Stationary Head Nozzel6.   Stationary Tubesheet7.   Tubes8.    Shell9.    Shell Cover10.  Shell Flange-Stationary Head End11.  Shell Flange-Rear Head End12.  Shell Nozzel13.  Shell Cover Flange14.  Expansion Joint15.  Floating Tubesheet16. Floating Head Cover17.  Floating Head Cover Flange

18.    Floating Head Backing Device19.    Split Shear Ring20.    Slip-on Backing Flange21.    Floating Head Cover External22.    Floating Tubesheet 23.    Packing Box24.    Packing Gland25.    Packing Gland26.   Klfjadlfkaj27.    Tierods and Spacers28.    Transverese Baffles or Support Plates

29.  Impingernent Plate30.  Longitudinal Baffle31.  Pass Partition32.  Vent Connection33.  Drain Connection34.  Instrument Connection35. Support Saddle 36.  Lifting Log37. Support Bracket 38. Weir39. Liquid Level Connection

FRONT ENDSTATIONARY HEAD TYPES

CHANNELAND MOVABLE COVER

BONNET (INTEGRAL COVER)

CHANNEL INTEGRAL WITH TUBE-SHEET AND REMOVABLE COVER

REMOVABLETUBE

BUNDLEONLY

CHANNEL INTEGRAL WITH TUBE-SHEET AND REMOVABLE COVER

SPECIAL HIGH PRESSURE CLOSURE

A

B

C

D

N

SHEEL TYPES

ONE PASS SHELL

TWO PASS SHELLWITH LONGITUDINAL BAFFLE

SPILT FLOW

DOUBLE SPLIT FLOW

DIVIDED FLOW

KETTLE TYPE REBOILER

E

F

G

H

J

K

X

DIVIDED FLOW

REAR ENDHEAD TYPES

FIXED TUBESHEETLIKE "A" STATIONARY HEAD

FIXED TUBESHEETLIKE "B" STATIONARY HEAD

FIXED TUBE SHEETLIKE "N" STATIONARY HEAD

OUTSIDE PACKED FLOATING HEAD

FLOATING HEADWITH BACKING DEVICE

PULL THROUGH FLOATING HEAD

U-TUBE BUNBLE

EXTERNALLY SEALEDFLOATING TUBESHEET

L

M

P

S

T

U

W

N

32 2 3 6 32 1 37 27 29 14 12 34 2

5

5 34 3712

BEM

8

33 6 3

36 4 3 34 5 31 34 12 1 30 21 27 32 91

34 5 6 10 12 34 35 35 331

Standards Of The Tubular Exchanger Manufacturers Association

CFU

36 4 3 5 34 31 12 34 23 27 28 8 7 32 15 23 24 25 22 36

1 34 5 3 106 33 35 35 34 12 19 20 21

AEP

36 34 5 3 10 1 2 28 12 34 27 23 24 26 24 23 15 1 36

4 3 1 6 34 12 35 35 34 12 34 5 3 4

Standards Of The Tubular Exchanger Manufacturers Association

36 4 3 5 34 31 31

1 34 3 10 355

6 12 25 7 8 27 28 18 36 37

36

3

15

18

33121311341235

Standard Of The Exchanger Manufactures Association

36 4 3 34 5 31

8 34 12 35

9

1 5 34 3 6 38 34 12 35 27 28 7 35 12 34 39

15 17 36 34

16

AKT

The following alterations can be suggested in order to achieve optimum piping arrangement.   a) Elbow nozzle permits lowering of heat exchanger to grade to have better accessibility to valves and instruments. (Refer Fig. 3.3.3)  b) Angular nozzle can save one or two bends in the pipe line.The maximum angle from the vertical centre line can be about 300. (Refer Fig. 3.3.4)  c) Horizontal exchanger can be turned vertical for conserving floor space. Vertical exchangers can be changed to horizontal when installation height is restricted

d) Exchanger saddle can also be relocated to adjust to a line-up or combined foundation design. (Refer Fig. 3.3.2)

 

Fig. 3.3.3

Fig. 3.3.4a Fig. 3.3.4b

Interchange flow media between tube side and shell side. This can give the following advantages…    If hotter liquid is allowed to flow through the tube, this will minimize the heat loss and/or avoid use of thicker shell insulation.    If high pressure fluid flows on the tube side, only tubes,

tube sheets, channels and cover have to be designed for high pressure. This reduces shell side thickness and the cost.

    Corrosive liquid should pass through the tube so that only the tubes and the channels have to be made of corrosion resistant material.

If one medium is dirty and the other is clean, passing clean through the shell will result in easier tube bundle removal and cleaning.

  Shell side volume is much more than the tube side and hence vaporization or condensation of free

flowing fluid is more effective in shell.

  When hazardous chemicals are water cooled, the water is passed through the shell. The tube leakage will contaminate the cooling water. On the other hand, the shell leakage can vent process material to the atmosphere.

 

Fig. 3.3.5

The piping associated with these vessels are simple. Economy of piping and access to valves and instruments depend on well-oriented nozzles. The nozzle and support orientation can be evaluated as below. (Refer Fig. 3.4.1)

      Inlet/outlet nozzles      Vents and Drains       Relief Valves/Rupture Disc       Level gauges       Pressure and Temperature tap-offs.       Manholes       Vessel saddles

Fig. 3.4.1 

 

Fig. 3.4.2 

 

Fig. 3.4.3 

 

Fig. 3.4.4

 

Fig. 3.4.5

Let us analyze the equipment layout and Piping design for a distillation column, which is more of an integrated unit than the individual equipment discussed earlier.

 Interactions between hydraulic requirements and piping

configurations require close attention to many fluid and mechanical details, in order to obtain the most efficient and economical distillation units.

 

Fig. 3.5.1

 

Fig. 3.5.2

 

Fig. 3.5.3

 

Fig. 3.5.4

The prime consideration in all these cases is the performance to achieve the process requirements integrated with economy.  

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