United States
Environmental Protection
Agency
Air and Energy Engineering
Research Laboratory
Research Triangle Park NC 27711
Research and Development
EPA/600/S7-89/011 Dec. 1989
4»EPA Project Summary
Technologies for
CFC/Halon Destruction
J. C. Dickerman, T. E. Emmel, G. E. Harris, and K. E. Hummel
This report presents an overview of
the current status of possible tech-
nologies used to destroy chloro-
fluorocarbons (CFCs) and halons,
chemicals implicated in the destruc-
tion of the stratospheric ozone layer.
The Montreal Protocol, an inter-
national treaty to control the
production and consumption of these
chemicals, allows countries to in-
crease production by the volume of
CFCs or halons destroyed, if the
destruction technology has been
approved by the Parties to the
Protocol. The Parties have neither yet
approved nor considered possible
destruction technologies. This docu-
ment is the first step in the United
States' review of such technologies,
and will serve as the basis for
additional work in this area.
This report is based on publicly
available articles and reports, and
personal contacts with various
individuals who are knowledgeable in
the field. The summary of the key
findings addressed the following
areas:
• The ability of the various technol-
ogies to effectively destroy CFCs;
• The environmental consequences
of such destruction;
• The ability of current emission
monitoring systems to verify that
the CFCs have indeed been
destroyed;
• The impacts of current regulations
on CFC destruction; and
• The existence of any significant
data gaps, along with recommen-
dations of future required work to
resolve any unanswered issues
resulting from the data gaps.
This Project Summary was develo-
ped by EPA's Air and Energy Engi-
neering Research Laboratory, Re-
search Triangle Park, NC, to announce
key findings of the research project
that is fully documented in a separate
report of the same title (see Project
Report ordering information at back).
Introduction
The U.S. Environmental Protection
Agency (EPA) requested an investigation
into several areas related to chloro-
fluorocarbon (CFC) and halon destruction
technologies:
• Currently and potentially available
destruction technologies;
• Potential environmental or health
effects posed by destruction by-
products; and
• Methods to monitor destruction
efficiency.
This report documents the results of a
limited scoping study based on publicly
available articles and reports, and
personal contacts with various individuals
who are knowledgeable in the field.
Technologies to Destroy CFCs
and Halons
Many technologies could potentially be
used to destroy CFCs and halons. Most
of these technologies are at a preliminary
level of development for application to
CFCs and halons. Only thermal incin-
eration is currently available and demon-
strated for CFC and halon destruction.
Other technologies have been pro-
posed for destruction of CFCs and
halons. Some of these technologies have
been commercially used for destruction
-------
of other types of wastes, but they have
not been demonstrated for CFCs and
batons. Each of these promising tech-
nologies is discussed below.
• Catalytic Incineration is similar to
thermal incineration, but the destruction
is achieved at lower temperatures by
use of a catalyst. The lower temper-
atures represent a potential savings in
fuel costs, but the application to data,
of catalytic incineration has been
limited to destruction of hydrocarbons
or chlorinated organics. If tests of
chloride-resistant catalysts are suc-
cessful with CFCs or halons, catalytic
incineration could be commercially
available in the near term (3 to 5
years).
• Pyrotysis is destruction using high
temperatures, but without excess oxy-
gen for direct combustion. This
approach offers potential for reduced
exhaust gas volume (resulting in
smaller, less costly gas scrubbers), but
has not been tested with CFCs or
halons. If demonstration tests were
initiated,, pyrolysis could be com-
mercially available for CFCs or halons
in the near term (3 to 5 years).
• Active metals scrubbing is a process
which uses sodium, zinc, or aluminum
metal to rapidly react with halogenated
compounds. It has only been com-
mercialized for destruction of PCB-
containing wastes. Active metals scrub-
bing could be commercialized in the
moderate term (5 to 10 years).
• Chemical scrubbing is a process that
uses a highly alkaline reagent to
destroy halogenated compounds. It has
only been demonstrated on the bench-
scale for PCB destruction. Chemical
scrubbing would probably be a long
term (10 to 15 years) commercial pos-
sibility.
• Wet air oxidation is a process that uses
a moderate temperature aqueous
stream with oxygen to destroy organic
compounds. Limited test data show
that CFC-113 can be destroyed by this
process, but its use is limited to dilute
aqueous wastes. The ultimate appli-
cation of wet air oxidation is
questionable because of the require-
ment for a dilute aqueous form, but it
could probably be commercialized for
some CFG or halon applications in the
moderate term (5 to 10 years).
• Supercritical water oxidation is similar
to wet air oxidation, but it operates at
higher temperatures and pressures.
The current application of supercritical
water oxidation is limited to destruction
of aqueous wastes containing chlorin-
ated organics. It is possible that this
technology could be commercialized
for specialty CFC or halon streams in
the moderate term (5 to 10 years).
• Corona discharge is a process that
uses energized electrons from an
ionized corona field to destroy many
organics. It is currently a development
project, but shows possibility for future
development. The commercialization of
corona discharge for destroying CFCs
or halons is a long term (10 to 20
years) possibility.
Environmental Implications of
CFC Destruction
Environmental concerns surrounding
CFC and halon destruction include
possible formation of potentially hazard-
ous products of incomplete combustion
(PICs), and acid and/or halogenated gas
emissions. PIC formation, in general, is a
poorly understood phenomenon, which is
further complicated for CFC destruction
systems since no data on PIC formation
exist. Data from hazardous waste incin-
erators have indicated that PIC formation
in a properly operated system is typically
less than 1 ppm. At these low levels, the
volumes of any PICs formed would be
small. The overall toxicity, however, is an
unresolved issue that requires additional
data to resolve.
Thermal destruction of CFCs or halons
also produces acid gases (HCI, HF, or
HBr) and/or free halogen gases (CI2, F2,
or Br2) when the halogen-containing
parent compound is broken down in the
incinerator. Both types of gases are
hazards because of their toxicity and
corrosivity, and will require scrubbing
with either a water or caustic solution to
react with the acid/halogen gases. These
aqueous waste streams must be sent to
wastewater treatment facilities before
discharge. Large quantities of waste salts
are generated. For each 1 Ib (0.45 kg) of
CFC-12 incinerated, neutralization of the
acid gases produced results in the
generation of roughly 1.5 Ib (0.68 kg) of
salts.
Monitoring Methods for CFC
Destruction
To monitor destruction, record keeping
procedures must be in place to track the
quantities of CFC compounds in the
waste fed to the incinerator, and then
methods must be available to monitor the
destruction efficiency achieved during
incineration.
The basic tracking procedure now in
use involves the preparation of a feed
record and a certificate of destruction for
each waste load that is incinerated. The
feed record includes information on the
weight and composition of the waste
load. This information is gathered when
the waste load is received by the in-
cinerator facility. After the waste has
been incinerated, the certificate of
destruction is prepared to document that
the waste was destroyed. This certificate
is sent to the waste originator to com-
plete the record keeping process.
Currently, continuous monitoring meth-
ods for measuring the destruction
efficiency of CFCs and halons do not
exist. Incinerators burning wastes that
contain CFCs must comply with the
Resource Conservation and Recovery Act
(RCRA) performance standards. RCRA
requires prelicense testing (trial burn) to
ensure destruction efficiency and to
define the range of operating parameters
for which the unit would be in com-
pliance.
Regulatory Impacts
Currently, the regulations that would
have the most effect on CFC disposal
operations are: (1) RCRA, which can
affect the handling and processing of
spent CFC wastes; and (2) the Clean Air
Act, which affects the allowable emis-
sions of acid gases. All regulatory pro-
visions should be able to be met and thus
should not create impediments to imple-
menting a CFC destruction program.
Data Gaps and Research
Needs
The four major areas of data gaps
identified in this evaluation are: (1) PIC
formation resulting from CFC destruction;
(2) technical design data on CFC thermal
destruction systems, particularly in the
area of corrosion and materials of con-
struction; (3) all aspects of halon destruc-
tion; and (4) availability of continuous
CFC or halon monitors to verify destruc-
tion.
These data gaps can be addressed
through short-term (2-5 years) research
initiatives which would be focused on
better characterizing thermal destruction
systems to make data available for future
developments. In addition to short-term
research initiatives, a longer-term (5-15
years) research program should also be
considered to promote the development
of the most promising destruction tech-
nologies now in various stages of devel-
opment.
&U. S. GOVERNMENT PRINTING OFFICE: 1989/748-012/07190
-------
1
-------
J. C. Dickerman, T. E. Emmel, G. E. Harris, and K. E. Hummel are with Radian
Corp., Research Triangle Park, NC 27709.
Paul M. Lemleux is the EPA Project Officer (see below).
The complete report, entitled "Technologies for CFC/Halon Destruction," (Order
No. PB 90-116 955/AS; Cost: $17.00, subject to change) will be available only
from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Air and Energy Engineering Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use $300
EPA/600/S7-89/011
------- |