&EPA
United States
Environmental Protection
Agency
EPA/540/MR-92/011
March 1992
SUPERFUND INNOVATIVE
TECHNOLOGY EVALUATION
Demonstration Bulletin
Cyclone Furnace Soil Vitrification Technology
Babcock Si Wilcox
Technology Description: Babcock and Wilcox's (B&W) cy-
clone furnace is an innovative thermal technology which may
offer advantages in treating soils containing organics, heavy
metals, and/or radionuclide contaminants. The furnace used in
the SITE demonstration was a 4- to 6-million Btu/hr pilot system.
The test facility, shown in Figure 1, is fired by a scaled-down
version of B&Ws commercial cyclone furnace. It is water-cooled
and simulates the geometry of B&W's single cyclone, front-wall-
fired cyclone boiler. This furnace is typical of full-scale, coal-fired
cyclone units in regard to furnace/convection gas temperature
profiles and residence times, NOX levels, cyclone slagging poten-
tial, ash retention in the slag, unburned carbon and flyash particle
size.
For the demonstration, natural gas was introduced into the cy-
clone furnace. Preheated combustion air (nominal 800°F) enters
tangentially into the cyclone furnace. The soil is introduced via a
soil disperser (nozzle) at the center of the cyclone. The gas
temperature out of the cyclone barrel is over 3000°F while the
gas exiting the furnace has a temperature over 2000°F with a 2
sec residence time.
The cyclone is designed to achieve very high heat release rates,
temperatures and turbulence. Paniculate matter from the soil
stream is retained along the walls of the furnace by the swirling
action of the combustion air and is incorporated into the molten
slag layer. Organic material in the soil is vaporized or incinerated
in the molten slag. The slag which has a temperature of 2400°F
exits the cyclone furnace from a tap at the cyclone throat and
drops into a water-filled tank where the material is quenched. A
small portion of the soil exits as flyash with the flue gas from the
furnace and is collected in a baghouse. A heat exchanger cools
stack gases to approximately 200°F before they enter the
baghouse.
Waste Applicability: This furnace can treat liquids, sludges,
or soils contaminated with organics, heavy metals and/or radio-
nuclides.
Demonstration Results: The demonstration took place at
B&Ws Alliance Research Center in Alliance, OH between No-
vember 4, 1991 and November 16, 1991. The process was
demonstrated using a Synthetic Soil Matrix (SSM) provided by
EPA's Risk Reduction Engineering Laboratory in Edison, NJ.
SSMs are well-characterized, clean soils which are spiked with
known concentrations of contaminants of concern. For this
study, the SSM was spiked with heavy metals (cadmium, chro-
mium and lead); semi-volatile organics (anthracene and dimethyl
phthalate); and simulated radionuclides (bismuth, strontium and
zirconium). Simulated radionuclides are non-radioactive metals
whose behavior in the cyclone furnace will simulate true radionu-
clide species.
Three replicaite tests were conducted at B&W's pilot facility. SSM
was fed into the cyclone at 170 Ib/hr. The total amount of SSM
SSM Feed
System
SSM
Sampling
Location
Slag and .,
Quench '
Water
Sampling
Location
Continuous Emissions
_ ,. . Monitor (CEM)
Sampling Locat,on sampling Location
Stack Paniculate
'ID Fan
Scrubber
(Not in Use)
Furnace
Stack
Natural
Gas
Soil
Injector
Cyclone
Barrel
. Slag
Quenching
Tank
Figure 1. Cyclone Test Facility
Printed on Recycled Paper
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treated during the three runs was about 1 ton; the total amount
burned during the entire demonstration was almost 3 tons. A
review of preliminary data reflects the following results:
• The slag produced complied with TCLP regulatory require-
ments. Average leachate concentrations for cadmium,
chromium, and lead were 0.1, 0.3 and 0.7 mg/L, respec-
tively.
• A 12 to 1 weight ratio of slag to flyash was achieved.
* Almost 95% of the non-combustible portion of the SSM
was incorporated within the slag. On average, over 75%
(by weight) of the chromium in the SSM was trapped in the
vitrified slag. In addition, the percentages for strontium
and zirconium retained In the slag were 85% and 95%,
respectively. The other metals in the SSM (bismuth,
cadmium, and lead) are considered "volatile" and lower
percentages of these metals were retained in the slag.
Metals which partitioned to the flue gas were captured by
the baghouse. Since the resulting baghouse solids failed
TCLP for cadmium and chromium, the baghouse solids
were treated as a hazardous waste. Approximately 150 Ib
of baghouse solids were collected during the entire dem-
onstration.
• The volume of slag produced was 28% smaller than the
feed SSM.
• Destruction and Removal Efficiencies (DREs) for both semi-
volatile organic spikes were greater than 99.99%.
• An average of 0.001 grains per dry standard cubic foot of
particulate (corrected to 7% O2) was emitted, which is less
than the RCRA regulatory limit of 0.08 grains per dry
standard cubic foot at 7% O2.
The average flue gas flow rate out the stack was 1250 dry
standard cubic feet per minute. The average exhaust gas
composition from the burning of SSM and natural gas was
approximately 5.6% O , 8.6% CO2, 359 ppm NO, 6 ppm
CO, and 8.4 ppm total hydrocarbons (measured as pro-
pane).
• The simulated radionuclides were immobilized within the
slag according to American Nuclear Society Method 16.1.
• The process formed products of incomplete combustion;
however, concentrations were very bw.
An Applications Analysis Report and a Technical Evaluation
Report describing the complete demonstration will be available in
the Fall of 1992.
For Further Information:
EPA Project Manager:
Laurel Staley
U.S. EPA Risk Reduction Engineering Laboratory
26 West Martin Luther King Drive
Cincinnati, OH 45268
(513) 569-7863 (FTS: 684-7863)
United States
Environmental Protection
Agency
Center for Environmental
Research Information
Cincinnati, OH 45268
BULK RATE
POSTAGE & FEES PAID
EPA
PERMIT No. G-35
Official Business
Penalty for Private Use $300
EPA/540/MR-92/011
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