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.

ROLE OF BLENDING IN THE REFINERY

3

Fig

ure

1. R

ole

of

ble

nd

ing

in

th

e r

efi

nery

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