Chemical Engineering September 2010 - 26

Combustion
air blower
Source: Ronald Bell
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www.flexim.de) compensates for drift
and deposit sensitivity in inline process
measurements of refractive index,
overcoming a key disadvantage of conventional
instruments.
Rather than measuring the critical
angle of refraction, the new refractometer
sets up a differential measurement
based on a method that measures light
transmitted through a bi-prism.
A parallel light beam crosses the
fluid to be measured, and is refracted
and split at the surface of the measuring
prism. The two intensity peaks
from the split beam are detected on
a charge-coupled device (CCD) sensor
that is positioned in the focus of an optical
lens. The distance between them
is correlated to the refractive index of
the fluid through Snell's Law (ratio
of the sines of the angles of incidence
and refraction equals the ratio of the
velocities in the two media).
While the critical angle approach can
be useful in the laboratory, its value is
diminished somewhat in process applications
because only the material
at the prism surface contributes to the
measurement. This characteristic can
be problematic because measurements
are sensitive to particles adhering to
the prism surface, and are not applicable
for low-flow conditions or highly
viscous materials. - Oct. 20, 3:30 PM
Cogeneration process has high
thermal efficiency, low emissions
The Ecoces Cogeneration system produces
electrical and thermal energy
with thermal efficiencies of 90 to 92%
and achieves exhaust emissions of less
than 5 ppmv for NOx and 10 ppmv
carbon monoxide. The cogeneration
system can be applied to both leanburn
and rich-burn internal-combustion
(IC) engines.
To achieve higher thermal efficiencies
than conventional systems, the
Ecoces system combines engine exhaust
from an IC-engine-driven generator
with combustion air (Figure
2). The controls allow the auxiliary
burner to fire a heat-recovery steam
generator at near stoichiometric oxygen-to-fuel
ratios, maximizing the
overall thermal efficiency and minimizing
emissions.
" This approach to cogeneration provides
for a means to produce steam at
After
burner
Boiler
DeNOx
catalyst
Economizer
Main header
CO oxidation
catalyst
Stack
Electrical
power
Generator I.C. engine
Pump
Valve
Jacket water
exchanger
Cooling tower
Chiller unit
FIGURE 2. To
achieve high
thermal efficiencies,
the Ecoces
cogeneration
system combines
engine
exhaust from a
generator with
combustion air
Cold water
Hot water
Flue gas
Fuel
varying rates, independent of electrical
load, " comments technology developer
Ronald Bell.
Bell, an industry consultant, originally
patented the technology in 1991,
then optimized the control system in
2005, and worked with General System
Co. Ltd. (Korea) to set up a commercial
demonstration in 2006. - Oct.
20, 11:50 AM
Catalyst system allows high-efficiency
propriolactone production
A process under development by Novomer
(Waltham, Mass.; www.novomer.
com) utilizes a novel aluminum-based
catalyst system that allows carbon
monoxide and ethylene oxide to react
to form propriolactone with greater
than 99% efficiency.
Propriolactone is a versatile chemical
intermediate that can be converted
to acrylic acid, acrylate esters, 1,3propanediol
and polypropriolactone
(PPL), a polymer that has similar
properties to polyethylene and polypropylene,
but is biodegradeable. The
new catalyst system, discovered by
Cornell University (Ithaca, N.Y.; www.
cornell.edu) professor Geoff Coates,
enables an economically viable route
to PPL, which has not yet been made
on a commercial scale.
In Novomer's process, the CO, ethylene
oxide and process solvent are combined
in a reactor with the catalyst
under mild reaction conditions. After
formation of propriolactone, the catalyst
is separated from the product and
recycled with the solvent.
Novomer says an ethylene-oxidebased
route to acrylic acid has strategic
advantages over current technology,
which is based on propylene oxidation.
Further, the company says in 2009, its
process was determined to have a cost
advantage of more than 30% over existing
acrylic acid processes.
24D-2 CHEMICAL ENGINEERING WWW.CHE.COM SEPTEMBER 2010
Novomer recently completed construction
of a continuous pilot unit to
verify the catalyst lifetime in a closed
loop system. Novomer is seeking partners
to commercialize the technology.
- Oct. 19, noon
Plate reactor can replace batch
processes with continuous ones
Alfa Laval's (Lund, Sweden; www.
alfalaval.com) ART plate reactor enables
some batch processes in pharmaceutical
production, as well as fine
and specialty chemicals, to convert to
continuous operation. The ART reactor
uses channeled plates to integrate
the mixing channel with heat transfer
surfaces, creating a modular, continuous
reaction system.
The ART plate reactor consists of a
series of cassettes with specially designed
channel plates at their cores.
Machined into the plates are process
and utility channels, which are designed
to optimize mixing and heat
transfer performance. Each cassette
has process inlet and outlet ports, as
well as secondary ports through which
reactants may be added or monitoring
devices may be inserted. Multiple cassettes
are typically stacked and held
together in a frame.
" Continuous reactors ... will not replace
all batch reactors, " Alfa Laval explains,
" but in cases where the chemistry
is limited by the batch reactor,
or where safety is an issue, the ART
plate reactor can help a great deal. "
Two plate-reactor models are commercially
available, covering the range
of laboratory trials to production of up
to 1,000 ton/yr. Standard plate reactors
are constructed with stainless steel or
Hastelloy, and can operate at temperatures
between -60 and 200°C without
any reactor changes. Design pressure
ranges from full vacuum to 20 bar. -
Oct. 19, noon
http://www.flexim.de http://www.alfalaval.com http://www.novomer http://www.cornell.edu http://WWW.CHE.COM
Chemical Engineering September 2010

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