Saybolt viscosity of petroleum products and especially for the lube oil it also consider as properties of lube oil

1. Duhok Polytechnic University
Zakho Technical Institute
Petroleum Department
Scientific Report
Name: Taha Samir Ali
Stage: 2nd
Stage
Subject: Petroleum and Gas Technology2
LAB
Experiment: Standard Test Method for
Saybolt Viscosity ASTM D88-99
Experiment No. : 2

2. Objective:
To determine saybolt viscosity of petroleum products at
specified temperature (21-99) °C.
Introduction:
This test method covers the empirical procedures for
Determining the Saybolt Universal or Saybolt Furol viscosities
Of petroleum products at specified temperatures between 21
and 99°C (70 and 210°F). It is recommended that viscosity
indexes be calculated from kinematic rather
than Saybolt viscosities.
There are two types:
1-saybolt universal viscosity: It is the corrected efflux time in
seconds of 60 mL of sample flowing through a calibrated
universal orifice under specified condition. The viscosity value is
reported in Saybolt universal seconds abbreviated SUS, at a
specified temperature. It is determine using an orifice of (1.76
±0.015) mm in diameter used for lubricants and distillates with
efflux time greater than 32 sec. and less than 1000 sec.

3. 2-Saybolt furol viscosity: It is s the corrected efflux time in
seconds of 60 mL of sample flowing through a calibrated orifice
under gravity at specified temperature. The viscosity value is
reported in Saybolt Furol seconds, abbreviated SFS, at a
specified temperature. This is determined using an orifice of
(3.15 ±0.02) mm in diameter used when "SUS" value is greater
than 1000 sec. The viscosity value is reported in-Saybolt Furol
seconds, abbreviated SFS, at a specified temperature. The "SFS"
is approximately one tenth the "SUS". Furol: refers to "Fuel and
road oils."
Apparatus:
1-saybolt viscosity test assembly (water or oil bath, electrical
heater, sample container with orifice and stopper, mixer).
2-Receiving flask.
3-Thermometer.
4-stop watch.

4. Procedures:
1. Clean viscometer and receiving flask with appropriate
solvent.
2. Place the receiving flask below the bottom of the viscometer.
3. Fill the bath to with water for test temperature less than 98
°C and oil for higher test temperature.
Place the sample in the viscometer container and insert a cork
stopper at the bottom of the viscometer.
5. Control bath temperature.
6. Snap the cork and start the timer.
7. Stop the timer the instant the bottom of the oil meniscus
reaches graduation mark (60 ml).
8. Record the efflux timer in seconds to the nearest 0.1 sec.
This will be the viscosity.
Results & Calculation:
1-Report the time in the seconds to in nearest 0.1 sec.
2-To draw the relationship between viscosity and temperature,
arranged a table contains (temperature and efflux) as follows:-

5. Temperature °C Efflux time (viscosity) in sec
1- 30°C
2- 35°C
3- 40°C
1- 503 sec
2- 409 sec
3- 336 sec
0
100
200
300
400
500
600
1 2 3 4
Relationship between Viscosity &
Temperatue

6. The viscosity in centistokes can be calculated using this
equation:
cSt=0.226 S-195/S for S 32-100
cSt=0.22*S-135/S for S>100
Where:cSt= viscosity in centistokes, S=viscosity in SUS
Calculation Kinematic Viscosity:
1. cst=0.22×S-135/S
=0.22×503-135/503
=110.66 - 0.2683
=110.3917 cSt
2. cst=0.22×S-135/S
=0.22×409-135/409
=89.98 – 0.3300
=89.65 cSt
3. cst=0.22×S-135/S
=0.22×336-135/336
=73.93 – 0.4017
=73.52 cSt

7. Discussion:
1-what is the effect of temperature on viscosity?
- When a liquid heats up, its molecules become excited and begin
to move. The energy of this movement is enough to overcome the
forces that bind the molecules together, for example, when honey
is cold it has a high viscosity and can be difficult to pour. When
heated in microwaves, the viscosity decrease and the honey flows
more freely.
2-what is used on the bath media of viscosity test? Why?
-In this method we use the Oil bath, because oil is for higher test
temperature or sometimes using water for less than 98 °C.
3-set another method to determine the viscosity?
- Calculating the dynamic viscosity using kinematic viscosity
(Standard Test Method for Viscosity of Transparent Liquids) by
using Viscometer.
4-what is the viscosity index of lube oil?
- It is the rate of change of viscosity between 2 temperatures. The
lower the Viscosity Index, the more the drop in viscosity as the oil
warms up. The higher the VI value, the less the drop in viscosity as
the oil warms up. Generally, the less it changes, across a range of
temperatures, the better.