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Introducing MethBr Scrubbing Technology: Instantaneous Capture
and Destroy for Quarantine/Preshipment, Critical, and Emergency Use
Peter J. Joyce
President
Value Recovery, Inc.
510 Heron Drive, Suite 301
Bridgeport, NJ 08014
e-mail: joyce@ptcvalue.com
Methyl bromide's reactivity has not been thoroughly explored as a capture-and-destroy
removal strategy to protect the ozone layer. This critical attributereactivityis
both methyl bromide's most beneficial attribute with respect to fumigation efficacy
and its Achilles' heel with respect to environmental impact. When used as a
fumigant, methyl bromide can interrupt an organism's internal chemical reactions,
thus shutting down the organism. In the upper atmosphere, methyl bromide reacts
at low temperatures with ozone, thus destroying the ozone layer's ability to
provide protective filtering of UV light from the sun. Harnessing methyl bromide's
reactivity in the form of a scrubbing solution that has been designed to provide
exceptionally high reaction rates is the key to a new capture-and-destroy strategy
that may supply the missing link in the methyl bromide phase-out program.
Value Recovery, Inc., of Bridgeport, New Jersey, believes that exploiting methyl
bromide's strong suit, its reactivity, can result in an effective, safe, and
cheap way to keep methyl bromide from ever reaching the upper atmosphere. The
process takes place in a "reactive scrubber." Methyl bromideladen
air is forced through the reactive scrubbing solution and the air emerges essentially
free of methyl bromide. A water-soluble organic compound or anion in the scrubbing
liquor reacts with the methyl bromide to form a benign organic product and sodium
bromide.
The technology used is based on phase transfer catalysis or PTC, whose salient
feature is that it brings reactants from different phases together to react
when they normally would not have a chance of reacting. PTC has been around
for over 30 years and is the subject of over 2,000 patents and 10,000 peer-reviewed
journal articles. Elite academics and specialty chemical companies use PTC to
make high-molecular-weight pharmaceutical chemicals and other similar sophisticated
molecules. PTC participates in at least one manufacturing step in over $10 billion
worth of specialty chemical sales. Currently, Value Recovery is the only company
dedicated to applying PTC to the environmental field. The company has identified
over 180 million kg per year of production-related waste documented in the U.S.
Toxic Release Inventory that could be transformed into salable products using
PTC technology. Funding for this work was initiated under the U.S.
Department of Energy Office of Industrial Technology.
A small-scale field demonstration of the technology was done on February 28,
2003, in conjunction with Rudi Scheffrahn of the University of Florida, who
is advocating using methyl bromide to destroy anthrax spores. During fumigation
of a University of Florida office trailer
containing surrogate anthrax spores, a slipstream containing over 20,000 ppm
(>80 oz/1000 ft3) of methyl bromide was charged to small gas washing
bottles containing the reactive scrubber solution. The outlet concentration
averaged 4 ppm and a steady-state value of 2 ppm was achieved in a 4-hour test
demonstrating over 99.9 percent removal in less than 1 second of contact time.
The air feed rate in the gas washing bottles was very low so these experiments
do not represent a conclusive test in terms of commercial viability. However,
the results do show that the reaction rate is exceptionally fast and that the
reaction rate does not control the overall removal rate of methyl bromide from
air. Thus, the approach is similar to scrubbing acid gases such as hydrochloric
acid with sodium hydroxide to make sodium chloride (table salt) and water. This
process also uses a reactive scrubber principle where the acid-base reaction
is very fast. Results from the Florida test are available at http://www.ptcvalue.com/app3.asp.
The scrubber liquor used in the Florida tests is not suitable for introduction
into the environment because the waste produced from it would be hazardous.
Thus, this particular formula would be used only for demonstration. However,
subsequent research results (as yet unpublished) from the company show that
a formula based on a nonhazardous scrubbing liquor is feasible and that the
company is actively working in this direction. The components of the scrubbing
liquor are both cheap and relatively easy to acquire. The next steps are to
scale the process up to conventional scrubber contacting equipment and to validate
the technology through the appropriate environmental authorities.
In summary, a new technology has emerged that can potentially provide an economic
and environmentally benign way to capture and destroy methyl bromide that continues
to be used under the exemptions from phase-out for emergency use, critical use,
and quarantine/preshipment (QPS). QPS applications such as fumigation of perishable
commodities are particularly well suited to this technology because of the limited
time available to accomplish dockside fumigations. The method is based on applying
reactive scrubber technology to totally remove highly reactive methyl bromide
and convert it to environmentally benign products. The gasliquid contact
times are on the order of seconds. Patent applications have been submitted.
[Fall 2003 Table of Contents] [Newsletter
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Bromide Home Page]
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Last Updated: April 9, 2004
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