Property estimation by data tables

CHEMICAL PROPERTY
ESTIMATION BY USE OF
DATA TABLES
A course under Finishing school (Technical)
Module: Campus to Chemical plant
Presented by: Mr. Mehul P Deshpande (Lecturer, Chemical Department)
Government Polytechnic Valsad
1This work is licensed under a Creative Commons Attribution 4.0 International License

CONTENT OUTLINE
• Need for chemical data and properties
• Sources for data tables
• Use of standard data tables for property
estimation
• Vapor Liquid Equilibrium for water system
• Use of steam tables
• Interpolation

Data Tables
A data table is a group of related facts arranged in labelled rows and
columns and is used to record information. Its purpose is to help sort, analyse
and compare data gathered from a experiment or research project.

Foundation of research
• Research Scientists and engineer use chemical property estimates
for chemical study, to design an instrument, or to investigate
suspect experimental measurement
Prediction of behavior of chemical substance
• For storage, handling and Precautionary purpose
Environmental pollution control
• Regulatory personnel and environmental specialists use the
information to screen chemicals for laboratory testing and to set
regulatory priorities
Need for chemical property estimation

Sources for Standard data
• Thermodynamic data ASHRAE Handbook, 1981: Fundamentals, American Society of Heating, Refrigerating
and Air-Conditioning Engineers, Atlanta, 1981
• Cengel, Y. (2014). Thermodynamics: An Engineering Approach. New York, NY: McGraw-Hill Higher
Education.
• SMITH, J. M., & VAN NESS, H. C. (1959). Introduction to chemical engineering thermodynamics. New York,
McGraw-Hill.
• Baum, Edward J. Chemical property estimation : theory and application. Boca Raton: Lewis Publishers,
1998. Print.
• Green,D.& Perry,R. (2007). Perry's Chemical Engineers' Handbook, Eighth Edition. New York, NY: McGraw
Hill Professional.
➢ More references list from which data is compiled in Perry's Chemical Engineers' Handbook-8TH edt are
available on pg:2-6

Conversion Factors

Conversion Factors (continued..)

Kinematic Viscosity vs Absolute Viscosity
9
• Dynamic viscosity (Pa-s): If you are interested in the interaction between molecules
that can be interpreted in terms of mechanical stress, temperature effect etc.
• Kinematic viscosity (cm2/s):It has been the standard in oil industries because of the
simplicity of the kinematic viscometers, it does not involve calculation of force
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Specific Gravity
Why Specific Gravity is Important
A. Configuration of a mixer
B. In applications with higher specific gravity, more
torque would be required to produce the desired
result.
C. If specific gravity was not taken into
consideration, and a mixer not optimized
accordingly, results would be unpredictable, and
motor damage and/or failure would likely occur
10
SG >1 (substance will sink in water)
SG < 1 (substance will float on water)

Specific Gravity (continued…)
11
Baumé scale
• The Baumé scale is a pair of hydrometer scales developed by French pharmacist Antoine
Baumé in 1768 to measure density of various liquids.
• One scale measures the density of liquids heavier than water and the other, liquids lighter
than water.
• The Baumé of distilled water is 0.
API gravity
• The American Petroleum Institute gravity, or API gravity, is a measure of how heavy or light
a petroleum liquid is compared to water.
• if its API gravity > 10 (floats on water)
• if its API gravity < 10 ( heavier and sinks)
• The API gravity scale is based on errors in early implementations of the Baumé scale.
Twaddell scale
• The Twaddell scale is a hydrometer scale for reporting the measured specific gravity of a
liquid relative to water. On this scale, a specific gravity of 1 is reported as 0, and 2 reports as
200.

Physical Properties

Physical properties (continued..)
Viscosity
(Transport property)

Vapor-Liquid Equilibrium
Phase diagrams

Phase diagrams (continued…)
T-V Diagram of pure
substance
P-V Diagram of pure
substance

PROPERTY TABLES
• For most substances, the relationships among thermodynamic properties are too
complex to be expressed by simple equations.
• Therefore, properties are frequently presented in the form of tables.
• Some thermodynamic properties can be measured easily, but others cannot and are
calculated by using the relations between them and measurable properties.
• The results of these measurements and calculations are presented in tables in a
convenient format.
• In the following discussion, the steam tables are used to demonstrate the use of
thermodynamic property tables

Steam Table

Steam Table (continued…)

Saturated Liquid–Vapor Mixture
Quality: (x) It is the ratio of mass of vapor to total mass of mixture.
• Its value is between 0 and 1.
• The quality of a system that consists of saturated liquid is 0 (or 0
percent)
• The quality of a system consisting of saturated vapor is 1 (or 100
percent).

Interpolation
Interpolation is a method of constructing new data points within the
range of a discrete set of known data points.
Use: To obtain intermediate value on property table for which direct
reference is not available.
Here Linear interpolation technique would be used to obtain the
required values

Interpolation (continued…)
Example
❖ Obtain specific volume of saturated water vapor at 18 °C
(vg@20°C-vg@15°C)/(20°C-15°C) = (vg@20°C-vg@18°C)/(20°C-18°C)
(57.762-77.885)/5 =(57.762- vg@18°C)/2
vg@18°C = 49.7128 m3/kg

Examples

Examples (continued…)

References
• Perry, Robert H., and Don W. Green. Perry's chemical engineers' handbook.
New York: McGraw-Hill, 2008.
• Cengel, Yunus A., and Michael A. Boles. Thermodynamics : an engineering
approach. New York, NY: McGraw-Hill, 2011

Property estimation by data tables

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