United States
Environmental Protection
Agency
Water Engineering
Research Laboratory
Cincinnati OH 45268
\>
'I
Research and Development
EPA/600/S2-85/073 Aug. 1985
Project Summary
Batch Pretreatment Process
Technology for Abatement of
Emissions and Conservation
of Energy in Glass Melting
Furnaces: Phase MA, Process
Design Manual
R. E. Miller, R. Raghavan, and R. R. Thomas
In glass manufacturing, the use of the
furnace stack gases to preheat the glass
batch showed promise in early feasibil-
ity studies for reducing energy costs
and reducing particulate discharged to
the stack. This study investigated the
environmental effectiveness of the con-
cept on an operating regenerative fur-
nace exhaust gas stream and identified
the capture potential of a packed bed
column with and without electrical en-
hancement. Also characterized were
the optimum operating parameters for
the palletizing operation.
This Project Summary was devel-
oped by EPA's Water Engineering Re-
search Laboratory, Cincinnati, OH, 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
A 1973 study of the glass manufactur-
ing process concluded that batch pre-
heating with furnace stack gases is a po-
tential option for controlling glass
manufacturing pollution while reducing
energy consumption. The potential for
faster glass melting with this process
would compound the energy savings
and return the materials normally lost
from the stack as particulate pollution
back to the melting tank.
A jointly funded project was formally
initiated in 1977 to develop and demon-
strate the capability of glass batch pre-
heating. The Department of Energy,
Corning Glass Works, and the U.S. Envi-
ronmental Protection Agency jointly
sponsored and funded this effort. That
project involved preliminary laboratory
studies and development of a process
design manual. The project was com-
pleted in late 1981 and reported in
EPA-600/7-81-038, May 1981.
Since the laboratory experimentation
adequately defined only the energy
conservation potential of the concept,
the report on that project recommended
additional research be conducted to fur-
ther define the pollution capture poten-
tial of the concept. This present project
was designed to accomplish that rec-
ommendation and includes conducting
pollution capture studies on a packed
bed using operating commercial regen-
erative furnace exhaust gases with ag-
glomerated glass batch pellets. Also in-
cluded are results of the pollution
capture potential of the packed bed
when it is electrostatically enhanced.
Conclusions are developed on the par-
ticulate pollution capture potential of
the packed bed with and without electri-
cal enhancement, on SOX capture effi-
ciency of the packed bed, and on glass
product quality.
During Phase I of this project, particu-
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late capture tests were conducted on a
miniature packed bed of pellets using
burner exhaust gases laden with com-
mercial grade sodium sulfate particu-
lates to simulate paniculate emissions
frpm a glass furnace. The results were
not considered conclusive because the
small-sized bed may have introduced
wall effects on the particulate capture
characteristics and because the sodium
sulfate particulates used were not rep-
resentative of the usual submicron-size
condensation products in an actual pro-
duction furnace environment. Thus, it
was recommended that further work be
carried out to conduct a more represen-
tative test program using a large-size
bed and actual soda-lime furnace ex-
haust gases.
Tests were conducted using a 0.76-m-
diameter x 1.52-m-deep bed and using
a slipstream of gases from a soda-lime
container furnace operated by Thatcher
Glass Manufacturing Company in their
Elmira, NY, plant. The soda-lime pellets
used in the tests were approximately 1.3
to 1.6 cm in diameter. The testing period
lasted 6 weeks and 19 tests run were
completed.
The objectives of these tests were to:
1. determine particulate capture effi-
ciencies in the packed bed and
electrified filter bed using EPA-
approved pollution testing proce-
dures,
2. determine the particulate size dis-
tribution of the emissions at the
inlet and outlet of the packed bed,
and
3. evaluate the effects of particulates
captured by the pelletized batch
with regard to the pellet's meeting
characteristics.
Pilot Plant Design and Equip-
ment
A schematic of the packed bed pilot
plant is shown in Figure 1. About 5% of
the volume of the operating commercial
furnace flue gas was passed through a
duct to the packed bed. The duct was
designed to include a damper for con-
trolling gas flow through the packed
bed system. The gases coming out of
the packed bed were drawn into a elec-
trified filter bed (EFB) pilot unit. The sys-
tem was used to complement the collec-
tion efficiency of the packed bed. The
sampling locations in the system were
(1) upstream of the packed bed, (2) be-
tween the packed bed and the EFB, and
(3) after the EFB. All sampling ports
were located at least eight diameters of
Packed Bed
Outlet Sampling
Cold Air Inlet
•£
Corona
Charger
. — Bed
1 Charger
Packed
Bed
® Packed Bed
Inlet Sampling
-f"j Cooling
I Section
Electrofied
Filter
Bed
MS,
/77
Flue
Figure 1. Schematic test set-up.
straight ducting upstream and two di-
ameters of straight ducting down-
stream of the sampling ports. The duct
material from the flue to the EFB was
made of stainless steel to provide for
high-temperature operation and to min-
imize corrosion inside the duct.
The pellets in the packed bed (Fig-
ure 2) were supported by a stainless-
steel wire mesh screen welded to the
bottom of the cylindrical portion of the
packed bed. Four access doors (approx-
imately 15 cm x 30 cm) on the side of
the packed bed were designed for sam-
pling, loading, and unloading the pel-
lets into the packed bed.
Testing Strategy and Experi-
mental Conditions
The overall strategy of the bed testing
was to move toward maximizing the
bed capture efficiency by setting the op-
erating conditions for each experiment.
Additional experiments were also con-
ducted to establish reproducibility of
testing and scale-up parameters. The
bed study variables were bed depth, gas
velocity, and gas temperature (Table 1).
The size distribution of the particulates
in flue gases was dictated by the fur-
nace operating conditions during test-
ing; however, the particle size distribu-
tion at the inlet of the packed bed
remained relatively constant. The spe-
cific operating conditions for the packed
bed testing are shown in Table 1.
Conclusions
The following conclusions are based
EFB
) Outlet
Sampling
Exhaust
Fan
on work with the 1.37-m-diameter pan
pelletizer:
• Pan angle has a significant effect in
determining pellet size.
• The optimum pelletizing rate in a
1.32-m-diameter pan is 635 kg per
hour with a depth-to-diameter ratio
of 0.26. This rate is 80% of the max-
imum.
• The pelletizer can be operated with-
out operator attention provided
All Dimensions
in Centimeters.
Door
Wire Mesh
Figure 2.
Packed bed dimensions, in centi-
meters.
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Table 1. Range of Experimental Variables
Function Studied Units Flange
Packed Bed:
Bed depth
Gas velocity
Gas temperature
EFB:
Gas volume
Gas temperature
Bed voltage
Corona current
m
m/sec
°C
m3/min
°C
Kv
mA
0.6-1.5
0.6-1.8
260-370
25-200
150-260
0-9.5
1.5-3.0
proper control of batch and water
feed rates is provided.
• Pelletizer wear, adding approxi-
mately 40 ppm iron into the batch,
does not cause color problems
when the pellets are melted.
• 70% to 80% of the water in pellets
should be removed from pellets in
the belt dryer before they enter a
shaft dryer or preheater.
• Wet soda-lime pellets will stick to-
gether when subjected to heat in ex-
cess of 225°C in a belt dryer.
• Fines generated in the shaft dryer,
which were not carried out in the
exhaust gas, amounted to 3% to 5%
of the weight of the pellets.
• Approximately 1.3 cm is the opti-
mum diameter pellet for durability
in handling.
• Crushing strength of a pellet de-
creases as the size of the pellet in-
creases.
• In a production system, wet pellets
should be screened to remove occa-
sional batch chunks generated in
the pelletizer.
• Wet pellet strength exceeded that
needed for handling between the
pelletizer and belt dryer.
• The surface of dried pellets had 30%
to 42% more SO4 than the inner
core.
• Inertial capture is the dominant
mechanism for soda-lime furnace
particulates in the packed bed.
• An increase in the packed bed depth
increases paniculate capture. An in-
crease in gas velocity increases par-
ticulate capture. A decrease in gas
temperature has little effect on
packed bed capture.
• An increase in bed voltage in EFB
increases particulate capture.
• S02 capture in the pellet bed (EFB)
was about 75%.
• The concept of pollution capture
from soda-lime furnace emissions
using electrified filter bed technol-
ogy was shown to be feasible.
• With the use of the gravel or soda-
lime pellets as collection media, the
particulate collection is greater than
95%.
• The EFB needs more power to ob-
tain the same collection efficiency
that the gravel bed obtains because
of the electrical properties of the
pellets.
The full report submitted in fulfill-
ment of Contract No. 68-02-2640 by
Corning Glass Works under the spon-
sorship of the U.S. Environmental Pro-
tection Agency.
R. E. Miller. Ft. Raghavan, and ft. R. Thomas are with Corning Glass Works.
Corning. NY 14831.
Charles H. Darvin was the EPA Project Officer, for information contact Roger
Wi/moth (see below).
The complete report, entitled "Batch Pretreatment Process Technology for
Abatement of Emissions and Conservation of Energy in Glass Melting Furnaces:
Phase HA, Process Design Manual." (Order No. PB 85-216 554/AS; Cost:
$13.00. subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield. VA 22161
Telephone: 703-487-4650
Roger Wilmoth can be contacted at:
Water Engineering Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
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United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use $300
EPA/600/S2-85/073
0000329 PS
PROTECTION ftGENCY
•&U.S. GOVERNMENT PRINTING OFFICE.1985—559-016/27110
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