pipe size

GENERAL SPECIFICATIONS FOR

LINESIZING DESIGN BASIS.

1.0 Introduction

The guidelines for sizing of Process and Utility pipelines for Chemical Process Plants are presented in the following sections.

2.0 Piping Engineering Hydraulics

A pipeline design is based on the hydraulics of the fluid flowing through it. Fluid hydraulics can be classified as following :

· Liquid Hydraulics.

· Vapour Hydraulics.

· Mixed Phase Hydraulics.

For a Preliminary estimate of size of a pipeline, an iterative procedure as follows is adopted:

1. Assume a size of pipe

2. Compute the corresponding velocity and pressure drop for the assumed pipe size

3. Check if the velocity and pressure fall within the recommended level

4. If the velocity or pressure drop does not fall within the recommended range, choose a different pipe size and repeat steps 2 and 3.

This process is carried out until a satisfactory size of pipe is obtained.

For the three hydraulic systems mentiones above, the recommended velocity and pressure drop are given below for different applications which are normally encountered in Process plants.

Piping systems should be designed taking into consideration capital cost and operating costs and with due allowance for noise erosion and corrosion limitations. Consider economic factors when and where applicable.

2.01 Liquid Hydraulics.

The following tables are to be used as a guide for the sizing of pipe lines in process and water service.

Recommended Velocity and Maximum D P for Carbon Steel Liquid Lines

Liquid Lines in Process and Equipment Service

Sr. Type of Service Velocity Maximum D P

No. ft/sec. m/sec. psi/100ft kg/cm2/100m

1. General

recommendation

5-15 1.5-4.6 4 0.92

2. Laminar Flow 4-15 1.2-1.5

3. Turbulent Flow

Liquid density

100 lb/ft3 1602

kg/cm3

5-8 1.5-2.4

50 lb/ft3 801

kg/cm3

6-10 1.8-3.0

20 lb/ft3 320 10-15 3.0-4.6

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WATER LINES

kg/cm3

4. Pump Suction

Boiling Liquid 2-6 0.6-1.8 0.5 0.115

Non-boiling liquids 4-8 1.2-2.4 1 0.23

5. Pump Discharge

0 - 250

gpm

0 - 57

m3/hr

6-8 1.8-2.4 6 1.38

250-700

gpm

57-159

m3/hr

8-10 2.4-3 4 0.92

>700 gpm >159m3/hr 10-15 3-4.6 2 0.46

6. Bottoms Outlet 4-6 1.2-1.8 0.6 0.14

7. Reboiler Trapout 1-4 0.3-1.2 0.15 0.035

8. Liquid from Condensor 3-6 0.9-1.8 0.5-0.11

9. Liquid to Chillers 4-6 1.2-1.8

10. Refrigerant Lines 2-4 0.6-1.2 0.4 0.09

11. Gravity Run LInes 3-8 0.9-2.4 0.4 0.09

12. Liquid Feed to Towers 4-6 1.2-1.8


No. ft/sec. m/sec. psi/100ft kg/cm2/100m

1. General Service 2-16 0.6-4.9 2 0.46

Diameter, inches

1 2-3 0.6-0.9

2 3-4.5 0.9-1.4

4 5-7 1.5-2.1

6 7-9 2.1-2.7

8 8-10 2.4-3.0

10 10-12 3.0-3.7

12 10-14 3.0-4.3

16 10-15 3.0-4.6

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2.02 VAPOUR HYDRAULICS

The following tables are to be used as a guide for the sizing of pipe lines in steam or vapour service.

RECOMMENDED VELOCITY AND MAXIMUM D P FOR CARBON STEEL VAPOR LINES

VAPOR LINES IN PROCESS AND EQUIPMENT SERVICE

20 and up 10-16 3.0-4.9

2. Pump Suction and Drain 4-7 1.2-2.1

3. Pump Discharge 5-10 1.5-3.0

4. Boiler Feed 8-15 2.4-4.6

5. Refinery Water Lines 2-5 0.6-1.5 2.5 0.58

6. Cooling Water 12-16 3.7-4.9 2 0.46

7. From Condensor 3-5 0.9-1.5


No. ft/sec. m/sec. psi/100ft kg/cm2/

100m

1. General Recommendation

Pressure Level

psig kg/cm2

P > 500 P > 35.1 2.0 0.46

200<P<=500 14.1<P<=35.1 1.5 0.35

150<P<=200 10.5<P<=14.1 0.6 0.14

50 <P<=150 3.5 <P<=10.5 0.3 0.069

0 < P <=50 0< P <=3.5 0.15 0.034

Subatmospheric 0.1 0.023

2. Gas Lines within Battery

Limits

0.5 0.12

3. Compressor Piping Suction 0.5 0.12

4. Compressor Piping discharge 1.0 0.23

5. Refrigerant Suction Lines 15-35 4.6-11

6. Refrigerant Discharge Lines 35-60 11-18

7. Tower Overhead

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STEAM LINES

Pressure (P > 150 psia) 40-50 12-15 0.2-0.5 0.046-

0.12

Atmospheric 60-100 18-30

Vacuum (P < 10 psia) 125-200 38-61 0.05-0.1 0.012-

0.02


No. ft/sec. m/sec. psi/100ft kg/cm2/

100m

1. General Recommendation

Maximum :

Saturated 200 61

Superheated 250 76

Steam Pressure :

psig kg/cm2

0 - 50 3.5

50 - 150 3.5 - 10.5

150 - 300 10.5 - 21

>300 >21

2. High Pressure Steam Lines

Short (L<600 ft) 1.0 0.23

Long (L>600 ft) 0.5 0.165

Short Leads 2.5 0.577

3. Exhaust Steam Lines 0.5 0.165

(P > 1 atm)

Leads to Exhaust Header 1.5 0.346

4. Feed Lines to Pumps and

Reciprocating Engines

12.5-15 3.8-4.6

5. Power House Equipment

and Process Piping (Saturated at P >=25 psig)

100-170 30.5-52

6. Boiler and Turbine Leads 115-330 35-100 3 0.69

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2.03 MIXED PHASE HYDRAULICS

The following basis shall be used as a guide for the sizing of pipe lines in mixed phase flow service.

Condensate Lines Velocity < Erosion Velocity

DP/100m < 0.2 kg/cm2 G

UNITS

The units and measurements to be used shall be those given below

(Superheated to P >= 200 psig)

MEASUREMENT UNIT

PRESSURE :(As guage) Kg/cm2

LOW PRESSURE : mmH2O

PRESSURE :(Draft or Vacuum) mmH2O

FLOW :

- Liquids m3/HR,l/HR

- Gas Nm3/HR

- Air Nm3/HR

- Steam Kg/HR

- Solids Kg/HR

TEMPERATURE : Deg.C

SPECIFIC GRAVITY:

-Water 1.0 at 4 Deg.C

-Air 1.0 at 0 Deg. C

& 1013 millibar

VISCOSITY : CP

DENSITY : Kg/m3

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CONVERSION FACTORS

The conversion factors to be used shall be those as given below

LENGTH : mm,cm or m

MEASUREMENT UNIT

Time Sec,Min,Hr,Day

Velocity m/sec

QUANTITY TO CONVERT METRIC CONVERSION

FROM UNIT FACTOR

Length inch mm 25.4

Safety Distance feet m 0.3

Stress , Pressure psig Kg/cm2 0.0703

Specific Heat Btu/Lb °F K. cal/Kg °C 1.000

Surface Tension N/m dynes/cm 1000

Latent Heat Btu/lb Kcal/Kg 0.556

Flow rate lb/hr Kg/Hr 0.454

Power Btu/hr K. cal/hr 0.252

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pipe size

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