Measurement of density S.G and API gravity

Sulaimani polytechnic university
college of engineering
petroleum and energy department

1. Technical College Of Engineering
Petroleum and Energy Engineering Department

Chemistry Laboratory
1
st
stage
(2016-2017)

Lab # 2(Density and Specific Gravity)
(Measurement of Density S.G and API gravity)



Prepare By: Zanyar nawzad hama ali

Date : 27/2/2017

Group : A

2. Aim :
 Calculate the density a substance from measurements of
it is mass and volume .
 Calculate the specific gravity of a liquid from it is density
 Compute the value of API (American petroleum
institute)





Introduction:

Determining the density, S.G and API gravity of the fluid is very
important to classified the fuel . this experiment will show us how to
determining API and S.G via two method .

Density is mass per unite value or density is a characteristic property
of the substance. the density of the substance is the relationship
between the mass of the substance and how much space it takes up
(volume ).

API gravity is used to quantify the quality of petroleum products
and it has range that measures the quality . and it depended on S.G
the higher S.G the lower API gravity .

3. Equipment :

 Granulate cylinder
 Hydrometer
 Scientific balance
 Pykno meter

4. Procedure :
Hydrometer method :
At first take a suitable graduate cylinder 500 ml and it should be
clean . the cylinder should be big enough because when we up put the
hydrometer it should (move )floats easily in the cylinder .
So, we fill cylinder with the sample (in out experiment we just used
diesel for the method ) after filing the cylinder with the diesel we
allowed sufficient time for the hydro meter to come to rest . and when
the hydrometer is flowed freely we took the scale reading. And at the
end we brought out the hydrometer and cleaned it.
Pico meter :
At first we took the emptied Pico meter and weight it (M1). Then we
filled the pyknometer with the sample that we wanted and weight it
again (M2) .(To yield the weight of the sample we subtract M2 from
M1)
The volume of the pyknometer that we used for kerosene was
5.305ml and for diesel was 4.928ml.
After those steps we measure the the density of fluid and API gravity
and specific gravity according to what we did in the lab.
API gravity =141.5/S.G(at15.6 c
ͦ
)-131.5
Note:
 API gravity >40 paraffinic (or light )based crude oil
 API gravity =33-40 mixed (or intermediate) based crude oil
 APIgravity< 33 naphthenic (asphaltic or heavy) based crude oil

5. Calculation:
M1 = 33.04 gm (empty)  m1 =mass of pyknometer
M2 = 71.97 gm ( crude) m2 =mass of pyknometer with crude oil
M3 = 82.60 gm (water) m3 =mass of pyknometer with water
V1 = volume of crude oil V2 = volume of water
 Sp.Gr =
&#3627408517;&#3627408518;&#3627408527;&#3627408532;&#3627408522;&#3627408533;?????? &#3627408528;&#3627408519; &#3627408532;&#3627408534;&#3627408515;&#3627408532;&#3627408533;&#3627408514;&#3627408527;&#3627408516;&#3627408518;
&#3627408517;&#3627408527;&#3627408532;&#3627408522;&#3627408533;?????? &#3627408528;&#3627408519; &#3627408536;&#3627408514;&#3627408533;&#3627408518;&#3627408531;

Sp.Gr =
&#3627408526;&#3627408514;&#3627408532;&#3627408532; &#3627408528;&#3627408519; &#3627408516;&#3627408531;&#3627408534;&#3627408517;&#3627408518; &#3627408528;&#3627408522;&#3627408525;
&#3627408535;&#3627409359;
&#3627408526;&#3627408514;&#3627408532;&#3627408532; &#3627408528;&#3627408519; &#3627408536;&#3627408514;&#3627408533;&#3627408518;&#3627408531;
&#3627408535;&#3627409360;
(V1=V2)
Sp.Gr=
&#3627408526;&#3627408514;&#3627408532;&#3627408532; &#3627408528;&#3627408519; &#3627408516;&#3627408531;&#3627408534;&#3627408517;?????? &#3627408528;&#3627408522;&#3627408525;
&#3627408526;&#3627408514;&#3627408532;&#3627408532; &#3627408528;&#3627408519; &#3627408536;&#3627408514;&#3627408533;&#3627408518;&#3627408531;
=
&#3627408526;&#3627408514;&#3627408532;&#3627408532; &#3627408528;&#3627408519; &#3627408529;??????&#3627408524;&#3627408527;&#3627408528;&#3627408526;&#3627408518;&#3627408533;&#3627408518;&#3627408531; &#3627408536;&#3627408522;&#3627408533;&#3627408521; &#3627408516;&#3627408531;&#3627408534;&#3627408517;&#3627408518; &#3627408528;&#3627408522;&#3627408525;−&#3627408526;&#3627408514;&#3627408532;&#3627408532; &#3627408528;&#3627408519; &#3627408529;??????&#3627408524;&#3627408527;&#3627408528;
&#3627408526;&#3627408514;&#3627408532;&#3627408532; &#3627408528;&#3627408519; &#3627408529;??????&#3627408524;&#3627408527;&#3627408528;&#3627408526;&#3627408518;&#3627408533;&#3627408518;&#3627408531; &#3627408536;&#3627408522;&#3627408533;&#3627408521; &#3627408536;&#3627408514;&#3627408533;&#3627408518;&#3627408531;−&#3627408526;&#3627408514;&#3627408532;&#3627408532; &#3627408528;&#3627408519; &#3627408529;??????&#3627408524;&#3627408527;&#3627408528;

Sp.Gr =
??????&#3627409360;−??????&#3627409359;
??????&#3627409361;−??????&#3627409359;

&#3627409365;&#3627409359;.&#3627409367;&#3627409365;−&#3627409361;&#3627409361;.&#3627409358;&#3627409362;
&#3627409366;&#3627409360;.&#3627409364;&#3627409358;−&#3627409361;&#3627409361;.&#3627409358;&#3627409362;

&#3627409361;&#3627409366;.&#3627409367;&#3627409361;
&#3627409362;&#3627409367;.&#3627409363;&#3627409364;
 0. 7855
Temperature (T) of crude oil = 18 c
ͦ

CR or α = 0.00066
Sp.Gr( at 60 c
ͦ
for 15.6 c
ͦ
) =Sp.Gr(at T)+ α ×( T -15.6)
Sp.Gr (at 60 c
ͦ
for 15.6 c
ͦ
) = 0.7855 + (0.00066)(21 c
ͦ
-15.6 c
ͦ
)
Sp.Gr = 0.789
API =
&#3627409359;&#3627409362;&#3627409359;.&#3627409363;
&#3627409358;.&#3627409365;&#3627409366;&#3627409367;
– 131.5 = 47.84 this value of (API) it mean

6. Discussion :
1- Explain which method is much accurate ?
Method two (pykometer is more accurate then the hydrometer and
the reasons belongs to those factory that affect the hydrometer like
temperature , carbon dioxide and presence of alcohol ..

2- What are factor effecting on the hydrometer ?
The factor that effects the hydrometer are :
 Temperature that causes the change in density
 Carbon dioxide
 Presence of alcohol

3- What are the advantage of API value ?
The more API gravity value of crude oil more expansive and more
effectual because it contain more gasoline and it is the most wanted
product at the whole world . the other advantage of API gravity vale
that we can determine the sulfur contain in crude oil , the higher
value of API gravity mean the less contain of sulfur , the high levels
of sulfur contains can be toxic and dangerous and can cause
breathing hazards .

7. Reference :
www.wikpedia.org
http://study.com
http://whatis.techtarget.com