Chemical Engineering December 2011 - 11

Edited by Gerald Ondrey
December 2011
Propane to storage
Commercialization is set for
a new alkylation process
n improved sulfuric-acid alkylation process
that reduces acid consumption by up
to 50% from that of conventional processes
will make its commercial debut in China. Developed
by Lummus Technology, a CB&I company
(The Woodlands, Tex.; www.cbi.com),
the technology will be used by Ningbo Haiyue
New Material Co. in a grassroots alkylation
plant to be built near Ningbo City, Zhejiang
Province. Scheduled for startup at the end of
2013, the plant will produce 600,000 metric
tons (m.t.) per year of alkylate.
A
Olefin feed
Reaction
Separation
Acid recycle
The process is similar to standard sulfuric
acid alkylation methods in that it uses
H2SO4 to react light olefins (C3-C5) with
isobutane to produce motor fuel alkylate (predominantly
C8 material). The innovation is a
contactor for mixing the acid and hydrocarbons.
Conventional alkylation units use large
impellers to mix the reactants, then separate
the alkylate product from the acid emulsion.
The product is purified by a series of acid and
alkaline washes. In contrast, Lummus carries
out the reaction in a large, vertical column,
using proprietary packing to achieve efficient
contacting between the components.
The design of the contactor improves mass
transfer over conventional alkylation and
enables an easier separation of the reaction
products, says Todd Vogt, Lummus Technology's
director of operations for refining.
" We have eliminated the acid and alkaline
water wash and use advanced coalescers
for cleanup, " he says. Also, the contactor alAlkylate
product
to storage
Fresh acid
Spent acid
lows the process to be done at around 27°F,
versus 40-50°F for mechanical mixing. The
colder temperature improves selectivity and
produces a higher-octane product, with low
acid consumption, says Vogt, noting that
mechanical impellers are unsuited to lowtemperature
operation because of the viscosity
of the acid emulsion. Another benefit
is that the process is readily scaled up - the
Ningbo plant will use only two vertical reactors
in parallel, versus about eight reactors
for conventional alkylation.
" We have come up with a simplified process
that eliminates a lot of equipment, so we expect
to cut capital costs by 20-30%, " says Vogt.
" Also, we estimate that operating costs will be
reduced, primarily through reduced acid consumption
and lower maintenance cost. "
Making amides with high yield, less waste
A
catalyst for making amides from alcohols
and amines under aerobic conditions has
been developed by Professor Shu Kobayashi
and his research group at the University
of Tokyo (Tokyo, www.chem.s.u-tokyo.ac.jp/
users/synorg/index_e.html).
The catalyst
- nano particles (2.4-nm dia.) of gold and
cobalt - is said to produce amides with
higher yield, less side reactions and almost
no waste, compared to alternative routes
based on carboxylic acids and amines, which
require a condensation agent that generates
a lot of waste. Yields of more than 90% have
been achieved in the laboratory for amides
that are typically used for synthesizing proNote:
For more information, circle the 3-digit number
on p. 62, or use the website designation.
Bio bisabolene
teins and textile chemicals.
For example, a targeted amide has been produced
from benzyl alcohol and benzyl amine
with a 96% yield using a 1-wt.% Au/Co catalyst
on a polymer-incarcerated, carbon-black
(PICB) support. The reaction required 12 h in
a tetrahydrofuran-water solvent at room temperature.
Over 30 other reactions using alcohols
and amines - including ammonia and
amino acids - have been studied, with yields
of over 90% for the corresponding amide. The
catalyst can be recovered and reused several
times without loss of activity, says Kobayashi.
The group plans to work with industrial partners
to develop commercial processes.
Through genetic engineering
of microbes, scientists from
Lawrence Berkeley National
Laboratory's (Berkeley, Calif.;
www.lbl.gov) Joint BioEnergy
Institute (JBEI) have coaxed
both bacteria (Escherichia
coli) and yeast (Saccharomyces
cerevisiae) to produce
a chemical precursor to bisabolane
- a critical step toward
an improved renewable
diesel alternative. The precursor
can be converted to
bisabolane when treated with
hydrogen gas under pressure.
Bisabolane, a plantderived
hydrocarbon chemically
related to turpentine,
was discovered to deliver
comparable performance to
standard D2 diesel fuel and
superior cold weather performance.
With continuous yield
improvements, biosynthetic
bisabolane could initially
serve as a cold weather additive
to diesel and biodiesel
formulations and, at higher
yields, could substitute for
these fuels. The JBEI team
inserted a gene from the
Grand Fir tree into E. coli
bacteria, and made genetic
adjustments designed to optimize
the production of bisabolene,
boosting the yield of
that chemical tenfold.
CHEMICAL ENGINEERING WWW.CHE.COM DECEMBER 2011 11
iC4 recycle
iC4 make-up
Fractionator
n-Butane
to storage
DeC3
http://www.cbi.com http://www.lbl.gov http://www.chem.s.u-tokyo.ac.jp/ http://WWW.CHE.COM
Chemical Engineering December 2011

Table of Contents for the Digital Edition of Chemical Engineering December 2011
