United States
Environmental Protection
Agency
Air and Energy Engineering
Research Laboratory
Research Triangle Park NC 27711
Research and Development
EPA/600/S7-86/015d Aug. 1986
\>EPA Project Summary
Coal Gasification
Environmental Data
Summary: Organics
Karl J. Bombaugh
This report summarizes the organics
data from environmental assessments
of several low- and medium-Btu coal
gasification processes conducted be-
tween 1977 and 1981 under the spon-
sorship of the U.S. Environmental Pro-
tection Agency. This data summary
focuses on the concentration, composi-
tion, and mass flow of organics in the
major streams of the various gasffier-
related processes. Many compounds in
the organics from the major gaseous-,
aqueous-, and solid-phase streams of
the several processes are identified. Or-
ganic compositions and stream concen-
trations among plants and plants'
streams are compared.
This Project Summary was devel-
oped by EPA's Air and Energy Engi-
neering Research Laboratory, Research
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 or-
dering information at back).
Introduction
This report provides a collection and
reduction of data that pertain to the or-
ganics in coal gasification process and
discharge streams. During the past
decade, EPA/AEERL has conducted
source test and evaluation programs at
commercial-, pilot-, and bench-scale
coal gasification facilities. The objec-
tives of these programs were to provide
test data for:
• characterizing regulated and non-
regulated species in process waste
streams;
• evaluating pollution control proc-
ess performance;
• developing sampling and analytical
methods for characterizing con-
stituents in process and waste
streams;
• evaluating the potential health and
ecological effects of process waste
streams;
• developing pollution control
schemes for treating gaseous, liq-
uid, and solid waste streams;
• providing input to federal, state,
and local regulatory agencies; and
• providing input to health studies.
These programs were conducted on
several types of gasifiers using different
coal feedstocks (Table 1). The facilities
were selected based on the greater
availability of process, gas, liquid, and
solid phase data. Results of these inves-
tigations are documented in a number
of referenced government reports, sym-
posjum proceedings, and journal publi-
cations. The tests varied in scope as
well as in breadth and dealt with a range
of pollutant groups (e.g., trace metals,
organics, sulfur species, nitrogen spe-
cies, and hydrocarbons). Some studies
dealt primarily with wastewater; others
investigated all types of streams:
gaseous, organic liquid, and aqueous-
and solid-waste. The data from several
of these test sites are distributed over
more than one document, so that sev-
eral documents must be consulted to
obtain comprehensive pictures of any
pollutant-concern relating to more than
one gasifier.
This report presents a compilation of
currently available data that relate
specifically to the organics levels in the
various streams of the several types of
coal gasifiers that were investigated
-------
Table 1. Source Test and Evaluation Program
Plant Gasification Process
Fuel
Fort Snelling
Glen-Gery
Holston
Kosovo
Modderfontein
Ptolemais
Worcester
Oberhausen-Holten
Duluth, University
Wellman-Galusha (low Btu)
Wellman-Galusha (low Btu)
Willputte/Chapman (low Btu)
Pressurized, fixed-bed gasifier
Koppers-Totzek entrained-bed
Koppers-Totzek entrained-bed
Riley Gas Producer (low Btu gasifier)
Texaco entrained-bed
Foster-Wheeler/STOIC (low Btu
NO Lignite
Anthracite
Bituminous Coal
Lignite
High Volatile
Bituminous Coal
Bituminous Coal
Lignite
Illinois No. 6
Bituminous Coal
Lignite
of Minnesota
Madison, PA
Homer City
Sasol 1
gasifier)
Kellogg-Rust/Westinghouse,
fluidized-bed process development
unit
Other Programs
Bi-Gas Pilot Plant
Lurgi Mark IV (modified)
WY Subbituminous
Pittsburgh No. 8 Bituminous
Coal
NO Lignite
Pittsburgh No. 8 Bituminous
Coal
KY No. 9 Bituminous Coal
under this program. In addition to pre-
senting a coherent compilation and
summary, these data have been consol-
idated to enable an interpretative evalu-
ation of:
• trends or correlations of organics
behavior across processes,
• trends or correlations in the context
of control approaches,
• specific characteristics of individual
processes, and
• recommendations for monitoring
commercial-scale systems to fur-
ther define environmental issues or
apparent trends in pollutant behav-
ior.
This data consolidation and evalua-
tion should make it possible to:
• recognize process-specific charac-
teristics for both synfuels produc-
tion and pollution control technolo-
gies which should influence the
areas of emphasis and scope of fu-
ture monitoring activities including
monitoring for Synthetic Fuels Cor-
poration (SFC)-supported facilities,
and
• define data interpretation and pre-
sentation approaches which will
help evaluate the data addressing
particular areas of concern in miti-
gating environmental and health
problems with existing and future
facilities.
In this report, "organics" refers to any
compound, or group of components,
that contain both carbon and hydrogen.
Compounds containing other elements
(e.g., oxygen, nitrogen, and sulfur) in
addition to carbon and hydrogen are
also considered to be organic.
Objectives
The overall objective of this report is
to present information about organics
in discharge streams of various coal
gasification processes. The streams of
concern may be discharged to the envi-
ronment or to other processes or con-
trol modules that in turn have discharge
streams. The principal concern here are
those streams that may impact the envi-
ronment. The information considered
here was gained from a series of tests
conducted on a variety of plants, both
pilot- and commercial-scale, over a
span of several years using an EPA-
approved protocol that evolved during
the program. The tests' results contain
an abundance of information on pollu-
tants. Because the objective of these
tests was to characterize the low/
medium Btu coal gasification technol-
ogy, the tests addressed a broad range
of pollutant concerns among which the
organics was only one of many.
Results and Conclusions
The conclusions drawn from this
evaluation point out similarities and dis-
similarities in the gasification processes
reviewed. The major similarities in the
data are:
• the tar-producing gasifiers, oper-
ated on coal with similar volatiles
content, produced about 30 kg
of condensable organics in the
product gases per metric ton of feed
coal;
• these organics generally were simi-
lar in composition; and
• none of the gasifiers showed a sig-
nificant trend toward the production
of any specific class of compounds
or species (hazardous or non-
hazardous).
The data indicate that the five tar-
producing gasifiers (Chapman,
Wellman-Galusha [Fort Snelling], Riley,
Foster-Wheeler/STOIC, and the Lurgi-
type [Kosovo]) produce similar
amounts of similar kinds of organics.
However, these data depend on the ana-
lytical techniques employed. Hundreds
of components were detected, many
species were identified, and many iden-
tifications were made at the component
class or subclass level (e.g., a Iky I ben-
zenes). The total identification of these
components was far from complete as
would be expected from the survey na-
ture of these studies. The non-polar or-
ganics identified were primarily
paraffins (including long straight chain
paraffins), aromatics (benzenes, alkyl
benzenes, naphthalenes, and alkyl
naphthalenes), and polycyclic aromat-
ics (including alkyl polycyclic aromatics
and polycyclic hydro-aromatics). The
polar organics consisted of hydroxy-
aromatics (phenols and alkyl phenols),
aromatic amines, and nitrogen hetero-
cyclics. The organics contained lesser
amounts of heterocyclic compounds
containing oxygen, sulfur, and multi-
heterocyclic compounds (e.g., thia-
zoles).
Detailed analyses tended to be pre-
directed to known components of con-
cern such as priority pollutants or se-
lected polynuclear aromatics and were
generally limited to single column gas
chromatography-mass spectrometry
without additional separation and con-
firmation. Speciation was not consis-
tent across the data base, and no valid
comparison of species distribution
across the gasifiers as a group can be
made. This limitation is made more
severe in several cases because the
mass of an extensive list of identified
compounds represented less than 10
percent of the total organic mass in a
stream. For the Chapman gasifier, how-
ever, relatively few components com-
prised the major portion of the speci-
ated mass. Overall, the speciations do
not provide a complete statement of
composition for the organics arising
-------
from the gasification process, but they
do identify and quantify many species
considered to be environmentally sig-
nificant. Additional compounds of equal
or greater significance also may have
been present. The gasifiers surveyed
displayed some dissimilarities which, in
general, were substantiations of the
overall behavior of organics in gasifica-
tion processes.
The organics in the crude product gas
result largely from thermal devolatiliza-
tion of coal. Therefore, it is not surpris-
ing that the product gas from the
Wellman-Galusha gasifier (Glen-Gery),
operated on anthracite, contained virtu-
ally no condensable organics. The bot-
tom gas from the Foster-Wheeler/STOIC
gasifier which is produced from the
coked coal was also practically
organics-free. The entrained-bed proc-
esses (Texaco, KRW, and Koppers-
Totzek) force the devolatilized material
to pass through the gasification zone so
their product gases were also much
lower in condensable organics. Trace
amounts of phenol were found in the
aqueous streams from these processes.
It is also noteworthy that the organic
loadings of the ash from the tar-
producing gasifiers were all between
300 and 600 ppm except for the Foster-
Wheeler/STOIC which was only 1 ppm.
Hydantoins were not detected
(<2 ppm) in wastewater from the
Kosovo Lurgi-type (dry ash fixed-bed)
gasifier, although they were found at
high levels (300-3000 ppm) in waste-
water from another fixed-bed gasifier.
Several conclusions concerning the
environmental significance of organics
in product gas can be made from the
collected data. Organics in crude
product gas can impact the environ-
ment either by escaping from the proc-
ess through a discharge stream or a leak
or by increasing the level of pollutants
in combustion flue gas.
The impact of organics escaping to
the environment is a process-specific
and a stream-specific problem because
the composition of the organics mixture
is influenced by temperature and by
contact with both aqueous and organic
solvents. For example, at the Chapman
site the organics discharged from the
stripper vent (45 percent VO) were dif-
ferent from the organics trapped from
either the crude gas (16 percent VO) or
the tar (5 percent VO).
Selective treatments, such as at
Kosovo where a combination of
aqueous scrubbing, selective gas clean-
ing (Rectisol), and selective water clean-
ing (Phenosolvan) are used, alter the or-
ganic composition considerably.
Lipophilic components were enriched in
the naphtha and medium oil, while the
hydrophilic components were concen-
trated in the water and accumulated in
the crude phenol. Both types of compo-
nents were concentrated, to some ex-
tent, by the thermally condensed tar. In
such a system, the composition of the
condensable or extractable organic is
stream specific.
A survey of organic mass loading can
indicate the potential for pollution from
a source, but it can neither describe the
composition nor define the risk poten-
tial. LC fractionation as used in this
study can indicate if the bulk of the or-
ganics is primarily polar or non-polar,
but more detailed analyses are required
to assess the severity of pollution or the
potential for environmental effects.
Nevertheless, organic composition and
mass loading data provide valuable in-
formation for use in environmental con-
trol technology.
-------
K. J. Bombaugh is with Radian Corporation, Austin, TX 78766.
William J. Rhodes is the EPA Project Officer (see below}.
The complete report, entitled "Coal Gasification Environmental Data Summary:
Organics, "(Order No. PB 36-209 095/AS; Cost: $16.95, subject to change) will
be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA22161
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, NC27711
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
k
U.S.OFFICIAL M/1
•-\PENALTY
I - 0 2
Official Business
Penalty for Private Use $300
EPA/600/S7-86/015d
0000329 PS
U S ENVIR PROTECTION AGENCY
CHICAGO
40,
It 60604
------- |