1 / 6 Next Page
Information
Show Menu
1 / 6 Next Page
Page Background

767

ISSN 1070-4272, Russian Journal of Applied Chemistry, 2014, Vol. 87, No. 6, pp. 767−772. © Pleiades Publishing, Ltd., 2014.

Original Russian Text

©

E.V. Chuparev, P.A. Zernov, O.I. Parputs, N.V. Lisitsyn,

2014, published in Zhurnal Prikladnoi Khimii, 2014, Vol. 87, No. 6, pp. 760

−766

.

CATALYSIS

Low Temperature

Isomerization of

n

-Hexane

on

Catalyst Systems Al

2

O

3

/ZrO

2

/SO

4

/Pt

E. V. Chuparev

a,b

, P. A. Zernov

a,b

, O. I. Parputs

a,b

, and N. V. Lisitsyn

a

a

St. Petersburg State Technological Institute (Technical University), Moskovskii pr. 26, St. Petersburg, 190013 Russia

b

JSC “RRТ Ltd.” ul. Serpukhovskaya 10, St. Petersburg, 190013 Russia

e-mail:

evgeniy.chuparev@globalrrt.com

Received May 5, 2014

Abstract

— As a result of investigating low temperature isomerization of

n

-hexane at 130, 140, 150, 160°C in

a flow reactor with a fixed bed of catalyst of the Al

2

O

3

/ZrO

2

/SO

4

/Pt type a ratio of components in the catalyst

system was selected and process conditions were defined, which allow to obtain highly branched high-octane

isomers with a yield of up to 40% relative to a transformed raw material. A kinetic model of the process was

proposed and kinetic parameters were calculated.

DOI:

10.1134/S1070427214060172

There is a need to implement new processes of

production of synthetic gasoline components to meet

contemporary more stringent requirements for fuels [1].

Isomerization of paraffinic hydrocarbons C

5

–C

6

is one

of the cheapest ways to increase the production of high-

octane gasoline components with improved environmen-

tal characteristics.

Known

isomerization processes

can be divided

into three types, which are differed mainly

by

applied

catalysts.

Each of these processes has

advantages and

drawbacks

.

The high-temperature

process based

on the use of

platinum

catalysts

on zeolite occurs at 250–290°C. This

type of catalyst

is less sensitive to sulfur

, water, and other

catalyst poisons

contained

in rawmaterial and hydrogen-

containing gas (

HCG) than

other

types of catalysts

.

How-

ever, the product

is

of a low octane

number

and

requires

circulation of hydrogen.

Medium temperature

isomerization

based on the use of

platinum catalysts on

sulfated zirconium oxide occurs at

120–180°C. The catalyst

is characterized by

a

resistance

to catalyst poisons

in a rawmaterial and

HCG

and

by

high

yield

of

branched isomers

of pentane

and hexane with

a high

octane number

,

but there is a need of hydrogen

circulation.

Low temperature

isomerization process

based

on

platinum catalysts

on chlorided

alumina

proceeds at

100–160°C. The catalyst

does not require

hydrogen cir-

culation. It

allows to obtain

a product with

high octane

number,

however, it is the

most sensitive to sulfur, water,

and other

catalyst poisons

contained

a raw material

and

HCG

, and also requires

impregnation

by

organochlorines

and subsequent purification

from

them that leads

to the

formation of waste water.

Currently, a process using platinum catalysts on sulfat-

ed zirconia is the most promising isomerization process

.

The aim of the study was determination of

the optimal

ratio of the components

in the catalyst of this type

, selec-

tion of

process conditions

,

which give

highly branched

isomers

of hydrocarbons

characterized by

the highest

octane numbers

, and also

construction of a kinetic model

of isomerization reaction

of

hexane

on

an optimum cata-

lyst sample

.

EXPERIMENTAL

Studies of samples

of catalysts in

the isomerization

reaction of

n

-

hexane

were conducted

in a

flow-through

setup

(JSC “RRT Ltd.” equipped with

isothermal

tubular

reactor of a radial type with stationary catalyst bed (Fig. 1).