Chemical Engineering December 2020 - 22

Technology Profile
Isopropyl Alcohol Production from Acetone
By Intratec Solutions
sopropyl alcohol (isopropanol or
2-propanol) is a colorless and
flammable liquid with a strong
odor. Isopropyl alcohol was
among the first petrochemical products
to be industrially manufactured
- it has been produced since 1920.
At that time, isopropanol was generated
through the indirect hydration of
propylene, a process that uses sulfuric
acid to react with propylene and
generate a compound that will react
with water to produce isopropanol.
Today, isopropanol is one of the
most produced C1 to C5 alcohols,
ranking third in commercial production,
behind methanol and ethanol.
The main industrial applications of
I
isopropyl alcohol are as a chemical
intermediate and as a solvent in the
manufacturing of cements, primers,
paints, varnishes, skin cleaners, perfumes,
lotions, shampoos and deodorants.
It is also used as a disinfectant
and antiseptic.
The process
The present analysis discusses an
industrial process for isopropanol
production. The process under
analysis comprises two main sections:
(1) reaction; and (2) purification
(Figure 1).
Reaction. Hydrogen is compressed
and fed, along with liquid acetone,
to the upper part of a circulation reactor.
The circulating mixture passes
through a gas-liquid separation
vessel. Part of the liquid is cooled
- removing the heat generated by
the exothermic reaction - and recycled
to the reactor. The remainder
Acetone
Hydrogen
Propylene
Indirect hydration
Direct hydration
Propylene
Propane
Isopropanol
FIGURE 2. Isopropanol production can occur via different pathways, as shown here
Hydrogenation
Acetone
n Raw material n Process n Main product n Byproducts
is cooled and routed to a second reactor,
followed by a second vaporliquid
separation stage. The liquid
portion obtained after the second
vapor-liquid separation is sent to the
purification stage. The vapor portion
is mixed with the vapors from the
first gas-liquid separation and also
sent to purification.
Purification. In the purification stage,
the vapors from the reaction are fed
to a condenser, where isopropanol
and acetone are recovered. Most of
the uncondensed vapors are recycled
to the hydrogen compressors.
The remaining portion of the hydrogen-rich
gaseous stream, the condensate
from the condenser and the
liquid product from the reaction are
fed to a deaeration tank to remove
any gases dissolved in the crude
liquid product. The crude product
is then subjected to dehydration by
means of molecular sieves, and finally
fed into a purification column, from
which purified isopropanol product
is withdrawn as a side stream. Lowboiling
components are separated
as the column's overheads product,
while high-boiling impurities are obtained
as the bottoms product.
Fuel
2
5
1
3
4
Isopropanol
Heavy
impurities
CW
ST
FIGURE 1. The diagram shows a process for isopropanol production via acetone hydrogenation
22
N2
7
6
8
1. Hydrogenation reactors
2. Hydrogen compressor
3. Deaeration
4. Molecular sieve column
5. Divided wall column
6. Cooling tower
7. Boiler
8. Air-separation unit
CW Cooling water
ST Steam
N2 Nitrogen
CHEMICAL ENGINEERING WWW.CHEMENGONLINE.COM DECEMBER 2020
Production pathways
The main raw materials for isopropanol
manufacture are propylene and
acetone. Propylene is reacted with
water directly, or indirectly (in the
presence of sulfuric acid), to form
isopropanol. Acetone, in turn, passes
though a hydrogenation process.
Figure 2 presents different pathways
for isopropanol production.
Economic performance
The total operating cost (raw materials,
utilities, fixed costs and depreciation
costs) estimated to produce isopropanol
was about $1,000 per ton
of isopropanol in the fourth quarter
of 2016. The analysis was based on
a plant constructed in the U.S. with
capacity to produce 60,000 metric
ton per year of isopropyl alcohol.
This column is based on " Isopropyl
Alcohol Production from Acetone
- Cost Analysis, " a report published
by Intratec. It can be found at: www.
intratec.us/analysis/isopropyl-alcohol-production-cost.
n
Edited
by Scott Jenkins
Editor's note: The content for this column is supplied by Intratec
Solutions LLC (Houston; www.intratec.us) and edited by Chemical
Engineering. The analyses and models presented are prepared on
the basis of publicly available and non-confidential information. The
content represents the opinions of Intratec only. More information
about the methodology for preparing analysis can be found, along
with terms of use, at www.intratec.us/che.
Light
impurities

http://www.intratec.us/analysis/isopropyl-alco http://www.intratec.us http://www.intratec.us/che http://WWW.CHEMENGONLINE.COM

Chemical Engineering December 2020

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