This document summarizes a student project to design a high temperature and pressure naphtha piping system. It includes the project members, objectives to understand piping design concepts and flexibility, and perform stress analysis manually and using CAESER II software. The problem statement is to design a 6" diameter pipe connecting a centrifugal pump and pressure vessel operating at 300°C and 21.4kg/cm2. The document outlines the design methodology, calculations, material selection, and references used.
2. PROJECT GUIDES:
DR. S JAYAKUMAR
(INTERNAL)
MR. SAJISH, SR.
ENGG. BPCL KOCHI
REFINERY(EXTERNAL)
PROJECT GROUP
MEMBERS
ANOOP M G
DEEPIKA SUDEVAN
SARATH
KRISHNAKUMAR
TOBIN MAMMEN
3. To understand the concepts of piping design and
flexibility of piping
PROBLEM STATEMENT :To design a high
temperature (300deg Celsius), high pressure
(21.4kg/cm2) NAPHTHA carrying pipe connecting
the given centrifugal pump and a pressure
vessel. The pipe is of 6” diameter and the pump
outlet is of 4” diameter.
To perform stress analysis of the system–
manually.
To verify the design using CAESER II.
4. HOOP STRESS –circumferential stress or tensile stress
acting in a direction tangential to the circumference.
Mathematically,
Hoop stress = (P x D)/(2xt)
Therefore pipe wall thickness “t” can be obtained
FLEXIBILITY- piping systems shall have sufficient
flexibility to prevent thermal expansion or contraction
or movements of piping support and terminals.
D y ≤ 0.03
(L-U)2
5. Dynamic effects are assumed negligible.
The end connected to vessel is assumed to be
fixed (i.e.; thermal expansion is neglected).
Temperature and pressure inside the piping
remains a constant throughout the entire service.
Outside conditions( temperature, pressure, wind
speed etc) are assumed to be ambient.
Effects of secondary stresses have been neglected.
Negligible variation in thermal expansion due to
different valves and flanges used are not
considered in thermal stress analysis.
The terminal displacements have been neglected.
Expansion of vessel is neglected.
6. 1. Identifying the service fluid, operating and
design conditions.
2. Selection of pipe material based on step 1.
3. Calculation of pipe thickness and selection
based on available sizes in market.
4. Routing of pipe.
5. Primary flexibility analysis and incorporation of
expansion loops.
6. Placement of anchor points and section wise
analysis of stresses
7. Location of supports and analysis of support
reaction and stresses.
8. Selection of Pipe fittings and accessories.
9. Selection of insulation material.
7. SERVICE FLUID – NAPHTHA
OPERATING CONDITION – TEMP = 300 deg.
C, PRESSURE = 21.4 kg/sq. cm
DESIGN CONDITION – TEMP = 316 deg. C,
PRESSURE = 38.66 kg/sq. cm
CALCULATION OF THICKNESS
tm = t + c
t = PD
2(SEW + PY)
8. tnominal = tm
100% - 12.5%
D = 6”
S =17.748 ksi
E = 1 (quality factor)
W = 1( weld reduction factor)
Y = d + 2c
D + d + 2c
STRESS RANGE DUE TO EXPANSION LOADING
Sb = √(Sb
2 + 4St
2)
10. PRIMARY FLEXIBILITY CHECK
DISPLACEMENT STRAIN
D y ≤ K1
(L – U)2
K1 depends on reference modulus of elasticity
and the allowable stress of the material
For convenience of calculation, K1 is taken as
0.03
15. ASME B31.3 -PROCESS PIPING
ASME B16.5 -FLANGES AND PIPE FITTINGS
ASME B16.9 -REDUCERS AND ELBOWS
ASME B31.1 -POWER PIPING
ASME B36.10 - WELDED AND SEAMLESS
WROUGHT STEEL PIPE
ASME B16.11 -FORGED FITTINGS, SOCKET-
WELDING AND THREADED
API 600 & API 602- VALVES
16. The manual designing process and stress
analysis have been completed
The design is found to be safe
17. “PIPING DESIGN AND ENGINEERING”-by ITT
GRINNELL INDUSTRIAL PIPING INC.
ASME CAREER COURSE MATERIAL
“PIPING AND PIPE SUPPORT SYSTEMS” –by PAUL
R SMITH & THOMAS J VAN LAAN
“ASME CODE BOOKS”