2015
Assistant lecturers
Belinskaya Nataliya Sergeevna
Kirgina Maria Vladimirovna
Institute of Natural Resources
Department of Fuel Technology and Chemical Cybernetics
Fundamentals of Petroleum Refining
Unit 6. Product Blending
INTRODUCTION
2
Refining processes do not generally produce
commercially usable products directly, but rather
semi-finished products which must be blended in
order to meet the specifications of the demanded
products.
BLENDING
4
The main purpose of product blending is
to find the best way of mixing different intermediate
products available from the refinery and some additives
in order to adjust the product specifications.
Straight run gasoline
Additives and
improvers
Products of downstream
processes
v Alkylate
v Isomerate
v Reformate
v FCC gasoline
Figure 2. Gasoline blending scheme
BLENDING
5
The final quality of the finished products is always checked by
laboratory tests before market distribution.
Gasoline is tested for
v octane number
v Reid vapour pressure (RVP)
v volatility
Diesel fuel is tested for
v flash point (cetane number)
v volatility
Gas oil is tested for
v diesel index
v flash point
v pour point
v viscosity
BLENDING
6
v specific gravity
v boiling point
v sulphur content
v octane number
v viscosity
v flash temperature
v pour point
v aniline point
v RVP
v cloud point
Properties of finished products
Additive properties Non-additive properties
BLENDING
7
Table 1. Typical properties for gasoline blending components
LSR gasoline – Light straight run gasoline
HSR gasoline – Heavy straight run gasoline
ADDITIVES
8
Gasoline additives
oxygenate additives antiknock additives
oxygen containing
compounds having high
octane number
chemical agents used to
destroy peroxides which
cause knock inside an engine
v Alcohols methanol, ethanol, isopropyl alcohol,
secondary butyl alcohol, tertiary butyl
alcohol
v Ethers diisopropyl ether (DIPE)
methyl tertiary butyl ether (MTBE)
ethyl tertiary butyl ether (ETBE)
methyl tertiary amyl ether
v Tetraethyl lead
v Fe-containing additives
v Mn-containing additives
v Amine containing additives
monomethylamine
TECHNOLOGY OF BLENDING
9
v Circulation method of blending
The blending is performed inside blending (mixing) tanks. It is
the most frequently used method.
v Blending inside apparatus with mixing devices
v Blending inside pipes
CIRCULATION TECHNOLOGY
10
Figure 3. Schemes of circulation blenders
a) blending tank with
circulation pump
b) blending tank with
circulation pump and ejector
1 – reservoir; 2 – spray; 3 – circulation pump; 4 – ejector
The product prepared inside blending tank is taken by special pumps and
pumped many times according to the scheme “tank – pump – tank” until the
mixture inside the tank becomes homogeneous in composition.
TECHNOLOGY OF BLENDING WITH
CIRCULATION PUMPS
11
Figure 4. Scheme of blending with
circulation pumps
Rcom – commercial tank
Straight
run
gasoline
Stable
catalysateN-butane Isopentane Isomerate MTBE
P-1 P-2 P-3 P-4 P-5 P-6
P-7 P-8
P-9
R-1 Rcom
REFERENCES
12
v Fahim M.A., Sahhhaf T.A., Elkilani A.S. Fundamentals of
Petroleum Refining: – First Edition. – Elsivier. – 2010. –
485 p.
Product Blending p. 237-261
v Chaudhuri U.R. Fundamentals of Petroleum Engineering
and Petrochemical Engineering. Taylor and Francis
Group. – 2011. – 380 p.
Blending Operations p. 139