22. Pressure and Temperature Drop in Pipelines
1. Introduction
This write-up gives design calculation for pressure drop and temperature drop in steam pipe line.
2. Example:
Given:
Pipe Size = Ø Do x T – Ø 323.9x25.4mm
Steam temperature = TI = 460 Degree C
Steam pressure = PI = 65 Kg/sq cm (a)
Enthalpy = I =792.4 k cal/kg
Specific weight = v = 0.04895cu m/ kg
Density = p = 1/0.0485 = 20.4 kg/ cu m
Friction factor = f = 0.02
Pipe length = L = 100m
Flow velocity = W = 30m/ sec
Inside diameter = d =(323.9 - 2 x 25.4) = 273.1 mm = 0.2731
Q = heat transferred, kcal/hr
Dt = temperature difference, Degree C
R = resistance for flow of heat, hr - Degree C/kcal
L = Length of pipe, m
Ti = pipe inside fluid temperature, Degree C
To = pipe outside ambient temperature, Degree C
Hi = convective heat transfer co-efficient inside pipe,k cal/hr-Degree C-sq m
Ho = convective heat transfer co-efficient outside pipe, k cal/hr-Degree C-sq m
K1 = thermal conductivity of pipe material, k cal/hr-Degree C-m
K2 = thermal conductivity of insulation material, k cal/hr-Degree C-m
R1 = pipe inside radius, m
R2 = pipe outside radius, m
R3 = insulation outside radius, m
Loge = logarithm to the base "e"