United States
Environmental Protection
Agency
Industrial Environmental Research
Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S7-81-021 Apr. 1981
Project Summary
Environmental
Characterization of
Geokinetics' In situ Oil Shale
Retorting Technology
Gerald M. Rinaldi, Jean L. Delaney and William H. Hedley
The objective of this research pro-
gram was to physically, chemically,
and biologically characterize air emis-
sions and water effluents from in-situ
oil shale retorting. Geokinetics, Inc.,
agreed to allow Monsanto Research
Corporation to sample and analyze
emissions and effluents from Retort
No. 17, a pilot-scale unit producing 30
barrels of crude shale oil per day and
located at the "Kamp Kerogen" site in
Uintah County, Utah. The potential
pollution sources tested were the
retort off-gases before and after mist
elimination, the exhaust from thermal
incineration of the demister outlet
gases, fugitive gas seepage through
the retort surface and around well
casings, retort water after oil separa-
tion, and evaporation pond water.
The three stack gas streams were
analyzed for criteria pollutants (carbon
monoxide, hydrocarbons, oxides of
nitrogen and sulfur, and paniculate
matter) as well as ammonia, arsine,
hydrogen cyanide, and trace elements.
Carbon monoxide, total hydrocarbons,
and Ci through Ce hydrocarbon frac-
tions were quantified in the fugitive
emission samples. Conventional pol-
lutants and water quality parameters,
organic priority pollutants, and trace
elements were measured in the sam-
ples of retort water and evaporation
pond water. Selected air and water
pollution samples were tested for
biological activity, using the Ames
mutagenicity assay, the Chinese ham-
ster ovary (CHO) clonal toxicity assay,
and the rabbit alveolar macrophage
(RAM) cytotoxicity assay.
This Project Summary was developed
by EPA's Industrial Environmental
Research Laboratory, Cincinnati, OH,
to announce key findings of the re-
search project that is fully documented
in a separate report of the same title
(see Project Report ordering informa-
tion at back).
Introduction
Oil shale has been recognized as a
potentially substantial energy resource
in the United States for more than 100
years. Recently, increasing dependence
on foreign oil supplies and rapidly
escalating oil prices have provided new
incentive for shale oil recovery from
deposits in Colorado, Utah, and Wyo-
ming. At least four domestic firms
(Colony Development Operation, Paraho
Development Corporation, Superior Oil
Company, and Union Oil Company) have
developed surface retorting processes,
in which oil shale is mined and crushed
prior to thermal processing in above-
ground facilities. The costs associated
with mining and transporting volumi-
nous quantities of raw shale and the
environmental impacts of spent shale
disposal may limit commercial applica-
tion of surface retorting technology.
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Considerable research is currently
being directed toward the development
of true or modified in-situ retorting
processes. True or modified in-situ
technologies, in which the shale bed is
hydraulically or explosively fractured
and retorting is carried out underground,
are now being developed by Dow Chem-
ical Company, Equity Oil Company,
Geokinetics, Inc., Rio Blanco Oil Shale
Company, and Occidental Oil Shale, Inc.
Despite the benefits of shale oil as an
alternative energy source, air emissions,
water effluents, and solid wastes associ-
ated with retorting could have adverse
impacts on the environment if uncon-
trolled. Byproduct gases released during
the retorting process may contain a
complex mixture of so-called "criteria"
pollutants (carbon monoxide, hydrocar-
bons, lead, oxides of nitrogen and
sulfur, and particulate matter) and other
non-criteria pollutant materials, such as
ammonia, hydrogen cyanide, and hy-
drogen sulfide, all of which could have a
deleterious effect on the West's pristine
air quality. Similarly, contaminated
wastewaters from oil shale processing
operations might degrade the existing
water quality if discharged without
proper treatment. Reliable, comprehen-
sive characterizations of air emissions,
water effluents, and solid wastes must
be performed now so as to identify
suitable control strategies prior to
commercialization of an oil shale in-
dustry.
In order to gather some of the neces-
sary data on potential environmental
impacts, the Environmental Protection
Agency's Industrial Environmental Re-
search Laboratory (IERL), Cincinnati,
Ohio, contracted with Monsanto Re-
search Corporation (MRC) to study air
emissions and water effluents from
horizontal in-situ oil shale retorting. To
meet this objective, MRC obtained
permission from Geokinetics, Inc., and
the Department of Energy's Laramie
Energy Technology Center to conduct a
sampling and analysis program at Geo-
kinetics' "Kamp Kerogen" site in Uintah
County in northeast Utah. Studies of
this nature may serve as a basis for
determining additional testing needs
and other efforts to define cost-effective
solutions to potential pollution problems.
This publication is a summary of the
complete project report, which can be
obtained from lERL's Energy Pollution
Control Division along with further
information on environmental aspects
of oil shale processing.
In-situ Retorting
Crude oil can be recovered from shale
by using heat to liquify a powdery
organic solid known as "kerogen." In-
situ retorting is the generic name given
to recovery processes in which under-
ground shale deposits are heated in
place after increasing the permeability
of the rock by fracturing and, in some
cases, partial mining. Geokinetics, Inc.,
is currently developing a true in-situ
process, that is, one which does not
involve any mining, that employs a
horizontally-moving flame front to retort
oil shale deposits located beneath
shallow overburden. Investigations of
this novel shale oil recovery technique
through privately funded laboratory and
field work date back to 1973, and a
cooperative agreement between Geoki-
netics and the Department of Energy
has been in effect since 1977.
In the Geokinetics horizontal in-situ
retorting process, a pattern of blastholes
is drilled from the surface, through the
overburden, and into the oil shale bed.
The holes are loaded with explosives
and then fired using a carefully planned
blast system. The blast yields a well-
fragmented mass of rock, with high
permeability, and also a sloped-bottom
bed which allows shale oil and co-
produced water to drain to a sump for
recovery by production wells; the result
is shown in Figure 1. After "rubbliza-
tion" of the shale deposit is completed,
surface equipment such as that shown
in Figure 2 is installed to process the
product gases released during the
retorting process.
The oil shale is ignited with burning
charcoal at the air inlet wells which are
Air Injection Well
Preblast Surface
drilled at one end of the retort. Injected
air establishes and maintains a horizon-
tally-moving burn front that occupies
the entire cross-section of the rubblized
bed. Off-gases containing oil mist exit
through output holes at the downstream
end of the retort. During Geokinetics'
ongoing process development efforts,
these off-gases, once above ground, are
passed through a three-chamber, packed-
tower mist eliminator to remove en-
trained oil and water, prior to combustion
in a thermal incinerator. Provisions are
made for firing propane as a supplemen-
tal fuel for the incinerator if the heat
content of the demisted gases is insuffi-
cient to maintain combustion. For com-
mercial-scale operations, instead of
being incinerated after mistelimination,
the retort off-gases will be either recycled
to the air inlet wells or fed to a gas tur-
bine to generate electricity.
The mixture of shale oil and water
which collects in the sump at the retort's
bottom is pumped by aboveground wells
to an oil-water separator tank, along
with the liquid recovered in the mist
eliminator described above. From the
separator, the aqueous layer is sent to
an evaporation pond, and the crude
shale oil is pumped to storage tanks for
holding prior to refining into marketable
products.
The specific oil shale retort selected
for testing in this sampling and analysis
program was designated as No. 17 by
Geokinetics. This retort, blasted in May
1978, contained 13,000 tons of frag-
mented oil shale, in a bed 17 feet thick,
72 feet wide, and 156 feet long, situated
under an average of 26 feet of overbur-
den. Retort No. 17 was ignited in mid-
April 1979, and MRC personnel per-
Liquid
Production Well!
I-Surface Uplift—- [•
Front' \ . n—•-•-. «= —• n
^- .,, t, ^ _
Retort
Off-Gases
..»
-*Oil/Water
Mixture
"/Sump*-
Figure 1. Sectional view of a Geokinetics horizontal in-situ oil shale retort.
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Retort Boundary
Pressure]
Blower
Pressuri
Blower
Figure 2.
Heat
Exchanger
Overhead view of surface
Geokinetics Retort No. 17.
formed field sampling and ana lysis from
July 16 to July 26. During that time
period, the flame front advanced ap-
proximately 6 inches per day, and the
crude shale oil production rate was 30
barrels per day. For comparison, Geoki-
netics' projected full-scale operations
will produce on the order of 2,000
barrels of shale oil each day, and other
developers have proposed commercial
facilities as large as 50,000 barrels per
day.
Stack Gas Sampling
EPA-approved methods were used to
collect samples of retort off-gases after
mist elimination (demister outlet) and of
the thermal incinerator exhaust gases
for quantification of air emissions.
Investigation of the demister outlet
gases, an essentially untreated stream,
provided information that would enable
the EPA to evaluate the potential of
pollution control methods other than
that implemented by Geokinetics, namely
incineration. Numerical results from
chemical analyses of the two types of
stack gas samples are summarized in
Table 1.
The amount of carbon monoxide in
the demister outlet gases, that is, in the
gases produced by the burning oil shale
retort, was greater than that of any of
the other air pollutants measured.
However, because of essentially com-
plete combustion in the thermal inciner-
acuum
'lower
[Gas Flow
Mist
\Eliminator
Vacuum
Blower
=&\ £
Thermal
Incinerator
Air Pollutant
Emissions
equipment for handling off-gases from
ator, the concentration of this criteria
pollutant in the exhaust to the atmos-
phere was less than the detection limit
of 0.1 percent by volume. Inspection of
the data indicates that incineration is
also a very effective control technique
for hydrocarbons. Even particulate
matter emissions are reduced somewhat
due to the fact that a substantial fraction
of the material that passes through the
mist eliminator consists of condensed
organic compounds which will burn.
Nevertheless, the residual emissions in
the incinerator exhaust implies that
inorganic solids, such as shale dust,
account for some of the particulate
mass. Extrapolating the pilot-scale
conditions and emission rate to Geoki-
netics' commercial-scale production of
2,000 barrels of shale oil daily, particu-
late emissions from incineration would
amount to nearly 300 tons per year.
Contrary to the behavior of the other
air pollutants, the emissions of nitrogen
and sulfur oxides are increased, relative
to amounts in raw retort off-gases, by
incineration. The concentration of nitro-
gen oxides in the incinerator exhaust
cannot be fully accounted for by the
reaction of nitrogen and oxygen from
the combustion air. However, nitrogen
oxides may also be formed during
incineration if nitrogenous compounds
such as ammonia are present in the
feed stream, as was the case at Geoki-
netics Retort No. 17. This hypothesis
was confirmed by the disappearance of
ammonia present in the demister outlet
gases. The substantial emissions of
sulfur oxides from the thermal inciner-
ator can be similarly explained, due to
oxidation of hydrogen sulfide (H2S) and
other sulfur compounds typically gener-
ated during oil shale retorting. Again
extrapolating, predicted sulfur dioxide
emissions from Geokinetics' commer-
cial facility amount to 5,400 tons annu-
ally, which may require some sort of flue
gas desulfurization for control. At the
other extreme, emissions of hydrogen
cyanide and trace elements, such as
arsenic, lead, and mercury, from oil
shale retorting were measurable but
only at or near the detection limits of
available analytical instrumentation.
Samples of the demister outlet gases
from Geokinetics Retort No. 17 were
also subjected to tests for biological
activity in order to assess potential
health and ecological effects. Using
standardized experimental procedures,
the oily particulate matter was demon-
strated to be mutagenic, that is, it
contained chemical substances that
may increase the risk of cancer. This
Table 1.
Chemical Analyses of Stack Gas Samples from a Pilot-scale In-situ
Oil Shale Retort
Mass flow rate. Ib/hr
Stack gas component
CRITERIA POLLUTANTS
Carbon monoxide (CO)
Hydrocarbons, total
Particulate matter
Nitrogen oxides (NO*)
Sulfur oxides (SOJ
NON-CRITERIA EMISSIONS
Ammonia (NH3J
Hydrogen cyanide (HCN)
Trace elements
Demister outlet
130
37
2.4
0.01
<0.03
2.9
0.01
<0.01
Incinerator exhaust
<8.4
1.3
0.9
2.0
18
<0.06
<0.01
<0.01
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observation must be taken into consid-
eration if oil shale developers are to
select and implement appropriate treat-
ment facilities for retorting emissions.
Fugitive Emissions
In addition to point-source emissions
such as those from the thermal inciner-
ator stack at Geokinetics Retort No. 17,
oil shale processing operations may
also give rise to so-called fugitive
emissions. Fugitive emissions consist of
diffuse, unconfined releases of panicu-
late matter, hydrocarbons, or other
pollutants into the atmosphere, usually
as a result of equipment leaks.
Geokinetics' explosive fragmentation
of an oil shale deposit causes the
surface of the retort overburden to
undergo noticeable uplift, creating
ground cracks of various sizes. Plant
personnel routinely seal the larger
cracks by filling with mud before retorting
begins, but all means of escape of
fugitive emissions are not eliminated.
Additional sources of fugitive emissions
are created by drilling instrumentation
wells into the oil shale bed. It has been
estimated that as much as one-third to
one-half of the total volume of gas
injected into Geokinetics' in-situ retorts
is not recovered at the outlet wells but
rather lost in the form of fugitive emis-
sions. Samples were collected using a
novel technique that combined the
applicable features of methods previously
used to measure fugitive emissions
from sources as diverse as growing or
decaying vegetation and petroleum
refineries.
Fugitive hydrocarbon emission rates
due to ground seepage at Geokinetics
Retort No. 17 ranged from 0.001 to0.09
pound per square foot of surface area
per day, a seemingly negligible amount.
However, accounting for the entire
retort surface as well as the contribution
from well leaks, the total fugitive hydro-
carbon emissions of about 13 pounds
per hour are ten times more than those
released to the atmosphere from the
incinerator stack. In addition, fugitive
emissions of carbon monoxide were
measured to be as much as 40 pounds
per hour, posing a potential health
hazard to personnel working on the
retort surface. The implications of
extrapolating this data on fugitive emis-
sions to commercial-scale facilities,
which may be 100 to 1,000 times larger
than Geokinetic's pilot retort, are that
additional research into methods for
both measurement and control is nec-
essary.
Water Pollutant Sampling
Water collected along with the product
oil from Geokinetics' in-situ shale
retorts is contaminated with a number
of potentially harmful pollutants. Sam-
ples of this "retort water" were analyzed
by standard methods in order to identify
the major chemical species present.
Development of new analytical technol-
ogy to resolve an ongoing controversy
among researchers regarding method
interferences due to the complex water
pollutant matrix was considered beyond
the scope of this project.
Table 2 lists the analytical results for
the pollutants and water quality param-
eters observed at the largest concentra-
tions in Geokinetics' retort water. As is
Conclusion
Treating shale to recover crude oil
may soon be an economically viable
alternative to continued depletion of
conventional petroleum reserves. Pilot-
scale process development research by
companies such as Geokinetics has
begun to provide the information nec-
essary for design and construction of
large commercial shale oil production
facilities. However, characterization of
emissions and effluents from oil shale
retorting has shown that significant
numbers and quantities of pollutants
present pose a complex environmental
control problem. Additional measure-
ment studies and technical and economic
evaluations of treatment alternatives
are necessary to prevent potential
adverse impacts by integrating pollution
control with oil shale development.
Table 2. Analysis of Wastewater from Geokinetics' Pilot-scale Oil Shale Retort
Parameter
Concentration, mg/L*
Alkalinity (as CaCOs)
Biological Oxygen Demand (BOD)
Bicarbonate (HCOz'l
Carbon, Total Inorganic (TIC)
Carbon, Total Organic (TOC)
Chemical Oxygen Demand (COD)
Chloride (CD
Nitrogen, Ammonia (NHs)
Solids, Total Dissolved (TDS)
Sulfur, Total (as S)
16,600
2,000
5.400
1.100
2.200
7.200
1,100
1.100
9,400
1,200
*1,000 milligrams per liter (mg/L) is equivalent to a 1% solution.
typical of wastewaters for oil shale
retorting, the data show the presence of
significant quantities of a wide variety of
pollutants. More specifically, this retort
water sample contained nitrogen com-
pounds (for example, ammonia), sulfur
compounds, soluble solids, and organic
compounds. As shown in Table 3, the
retort water collected at Geokinetics
also contained certain "organic priority
pollutants" (acrylonitrile, benzene,
phenol, toluene) and trace elements
(arsenic, boron, iron, strontium) in
amounts on the order of one part per
million. The presence of these poten-
tiaIly toxic materials makes treatment of
oil shale retorting wastewaters for
discharge or process recycle, already
difficult because of the number and
amount of "conventional" pollutants
present, a truly formidable challenge for
both the EPA and industry.
Table 3. Organic Priority Pollutants
and Trace Elements in Geo-
kinetics' Retort Water
Component
Concentration. mg/L"
ORGANIC PRIORITY POLLUTANTS
Acrylonitrile 0 25
Benzene O 37
Phenol 0.67
Toluene 0 28
TRACE ELEMENTS
Arsenic IAsl 1.6
Boron IB) 61
Iron IFe) 0.8
Strontium /Sr) 0.7
"Milligrams per liter.
4
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Gerald M. Rinaldi, Jean L. Delaney, and William H. Hedley are with Monsanto
Research Corporation. Dayton, OH 45407.
Robert C. Thurnau is the EPA Project Officer (see below).
The complete report is in two parts:
"Environmental Characterization of Geokinetics' In situ Oil Shale Retorting
Technology," (Order No. PB81-163 727; Cost: $9.50)
Environmental Characterization of Geokinetics' In situ Oil Shale Retorting
Technology: Field and Analytical Data Appendices," (Order No. PB 81-163 735;
Cost: $3.50 (microfiche only))
These reports will be available only from: (costs subject to change)
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Industrial Environmental Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
> U.S GOVERNMENT PRINTING OFFICE. 1061.757-012/7049
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