United States
Environmental Protection
Agency
Industrial Environmental Resea
Laboratory
Research Triangle Park NC 2771
Research and Development
EPA-600/S7-82-057b Mar. 1983
Project Summary
Hitachi Zosen NOX Flue Gas
Treatment Process:
Volume 2. Independent
Evaluation
J. M. Burke
Nitrogen oxide (NOX) emissions
from stationary sources may be
reduced by 80 - 90% by applying
selective catalytic reduction (SCR) of
NOX with ammonia. In the interest of
furthering the development of this
technology, EPA sponsored pilot scale
tests of two SCR processes treating
flue gas slipstreams from coal-fired
boilers. One of the processes was the
Hitachi Zosen (HZ) process. An inde-
pendent evaluation of the pilot plant
tests of the HZ process shows that the
process can reduce NO« emissions
from a coal-fired boiler by 90%. Initial
tests resulted in plugging of the
catalyst. But a new catalyst with
larger gas passages was tested: it
operated for 5500 hours without any
signs of plugging. An energy analysis
indicates that the HZ process energy
requirements equal 0.3% of the
boiler's capacity. Process costs were
estimated based on the pilot plant
test results. Estimated capital invest-
ment and annual revenue require-
ments for the HZ process are $44/kW
and 2.91 mills/kWh, respectively.
These costs are slightly lower than
previous estimates for the process.
This Project Summary was devel-
oped by EPA's Industrial Environ-
mental 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
ordering information at back).
Introduction
Selective catalytic reduction (SCR) of
NOX with NH3can reduce NOx emissions
by 80% or more. As such, SCR repre-
sents the most effective process avail-
able for controlling stationary source
NO, emissions. For a utility application
of SCR, a catalytic reactor is located
between the economizer and air pre-
heater sections of the boiler. At this
location the flue gas temperature is 300
- 400°C (570-750°F), which is optimum
for the catalytic activity. Ammonia is
injected into the flue gas upstream of
the catalyst and reacts with NOx on the
catalyst surface to form elemental
nitrogen and water.
Most SCR processes were developed
and are being operated commercially in
Japan, primarily on gas- and oil-fired
sources. However, in the U.S., SCR
systems are now being installed on a
limited basis. The most notable applica-
tion is a demonstration system that is
being constructed to treat half of the
flue gas from Southern California
Edison's 215 MWe Huntington Beach
Unit No. 2 (an oil-fired boiler). Operation
of this system is expected to establish
-------
SCR as a commercially available tech-
nology for oil- and gas-fired sources in
the U.S.
In Japan, development efforts are
currently aimed at applying SCR to coal-
fired sources. To date, most of the SCR
process vendors in Japan have operated
pilot units on slipstreams from coal-
fired boilers. In addition, there are now
four full-scale SCR systems treating
flue gas from coal-fired boilers; eight
other units are scheduled for start-up in
1982 and 1983. These development
efforts are rapidly establishing SCR as
commercially available for controlling
NO* emissions from coal-fired sources
in Japan.
The transfer of SCR technology from
Japan to the U.S. for coal-fired applica-
tions presents a potentially significant
problem. Since most coal-fired boilers
in the U.S. operate electrostatic pre-
cipitators (ESPs) downstream of the air
preheater, a typical SCR application
would expose the catalyst in the reactor
to the full particulate concentration
from the boiler. Although tests have
been conducted in Japan in which the
catalyst was exposed to high particulate
concentrations with no adverse effects,
the differences in the composition of
particulates from U.S. and Japanese
coals could impact SCR operation.
To further the development of SCR
technology and to determine how
differences between Japanese and U.S.
coal/particulate properties impact the
performance of SCR processes, EPA
sponsored pilot scale (0.5 MW equiva-
lent) tests of two SCR systems. One of
the SCR systems was the Hitachi Zosen
(HZ) process. The HZ pilot plant pro-
cessed a flue gas slipstream from a coal-
fired boiler. The contractor responsible
for the design and operation of the pilot
plant was Chemico Air Pollution Control
Corp. (now General Electric Environ-
mental Services Corp.), the North
American licensee for the HZ process.
Chemico was also responsible for
collection, evaluation, and reporting of
the test data.
Primary objectives of the pilot plant
test program sponsored by EPA were:
(1) to demonstrate the ability of the HZ
process to achieve a 90% reduction in
NOx emissions, and (2) to determine the
long-term impacts on catalyst perform-
ance which result from processing flue
gas from a coal-fired utility boiler.
In conjunction with the pilot plant test
program, EPA contracted with Radian
Corp. to independently evaluate the
processes tested based on the pilot
plant results. This document summa-
rizes the results of the independent
evaluation of the HZ process. It includes
a discussion of the results of tests
conducted by both Chemico and Radian
and the results of Radian's independent
evaluation of the HZ process. A separate
report (Volume I) covering the detailed
results of the pilot plant test program
has been prepared by HZ.
Program Objectives and
Approach
The independent evaluation of the HZ
pilot plant test program conducted by
Radian Corp. had three major objectives:
(1) to provide independent validation of
the process measurements made by
Chemico; (2) to quantify changes in the
emission rates of secondary pollutants
(pollutants other than NOX) across the
pilot plant reactor; and (3) to complete a
technical and economic evaluation of
the HZ process including identification
of areas which require further develop-
ment or investigation.
To validate the measurements made by
Chemico, a quality assurance program
was implemented. This program used
EPA reference methods and other
standard measurement techniques to
make independent audits of critical
process parameters; e.g., flue gas flow-
rate and NH3 injection rate. In conjunc-
tion with the quality assurance program,
the continuous NOX monitors were
subjected to certification tests designed
to determine their ability to make
accurate repeatable measurements.
These certification tests included
measurement of the continuous moni-
tors relative to accuracy, drift, calibra-
tion error, and response time.
Concurrent with the quality assur-
ance program, a stack sampling program
was conducted to measure changes in
secondary process emissions across the
SCR reactor. This approach required
simultaneous sampling of the reactor
inlet and outlet for\the species of
interest. The samples were then ana-
lyzed and differences between inlet and
outlet concentrations determined.
Based on the results of the quality
assurance program, the stack sampling
program, and the test data collected by
Chemico, an evaluation of the HZ
process was completed. This evaluation
consisted of several steps. First, the test
data were analyzed and reduced to a
form which could be used to predict
process performance for a specified set
of operating conditions. Then, using the
reduced test data and the results of the
stack sampling program, material and
energy balance calculations were
completed for a 500 MWe coal-fired
application of the HZ process. The basis
for these calculations was identical to
that used by TVA in developing cost
estimates for the HZ process and
presented in "Preliminary Economic
Analysis of NOX Flue Gas Treatment
Processes."' The results of the material
and energy balance calculations were
then used to develop a modified esti-
mate of total capital investment and
annual revenue requirements for a 500
MW coal-fired application of the HZ
process. Finally, the test data were re-
viewed and areas requiring further in-
vestigation/quantification were identi-
fied.
Results
Several areas which influence the
technical andeconomicfeasibrlityof the
HZ process were examined as part of
this study:
• Pilot plant test results.
• Results of Radian's independent
tests.
• Results of a 500 MW conceptual
design of the HZ process.
• Material balance calculations for a
500 MW process application.
• Energy balance calculation for a
500 MW process application.
• Estimated capital investment and
annual revenue requirements for a
500 MW HZ process application.
The following discussion summarizes
the results of the evaluation of each of
these areas. Overall conclusions on the
technical and economic feasibility of ap-
plying the HZ process to a coal-fired
boiler are presented later.
Pilot Plant Test Results
The test program at the HZ pilot plant
was initiated in June 1979, and was
completed in January 1981. During this
period, the pilot plant processed a flue
gas slipstream from between the
economizer and the air preheater of the
coal-fired Unit 3 at Georgia Power Co.'s
Plant Mitchell Station. Design flue gas
flowrate to the pilot unit was 1700
NmVhr (1060 scfm), and flue gas was
processed for about 10,000 hours.
The pilot plant test program involved
examination of three charges of catalyst
material under a variety of test condi-
tions. In general, these tests were
divided into two categories: optimiza-
tion tests and demonstration or long-
term tests. The objective of the optimiza-
tion tests was to identify operating
-------
conditions which would reduce NOx
emissions by 90% at a minimum cost for
operating the process. The major
objective of the demonstration tests
was to document the ability of the
process to achieve a 90% reduction in
NOX emissions for 90 days.
The objectives of the pilot plant tests
conducted by Chemico were exceeded.
The NOx reduction efficiency of the plant
averaged over 90% during the 90 day
demonstration test; the average was
89.8% over 5 months of operation. This
included several test periods during
which the NHa/NOx ratio was varied to
determine its effect on NOx reduction
efficiency. If these test periods are
excluded from the averages, the NOx
reduction efficiency during the 5
months of operation would be greater
than 90%.
Other significant results of the test
program showed that neither tempera-
ture nor flowrate has any significant
effect on NOX reduction efficiency
within a range about the design level.
These results indicate that process
performance should not be impaired at
boiler loads below the design level. As a
result, no temperature or flow control
would be required for a full-scale
application of the HZ process.
During the test program, three
catalyst charges were examined: two of
these (NOXNON 500) experienced
severe plugging problems after about
2000 hours of operation. When replaced
with the NOXNON 600 catalyst, which
has larger gas passages, no further
plugging problems were observed. The
original plugging was believed to be due
to the adhesiveness of the fly ash. At
high temperatures, fly ash samples
collected from the power plant were
found to agglomerate.
Tests with the NOXNON 500 catalyst
did not last long enough to get a good
measure of catalyst activity, but results
of the NOXNON 600 tests showed a
gradual decline in catalyst activity with
time. After 5500 hours of operation,
activity of the NOXNON 600 had
dropped slightly, but it was still possible
to achieve 90% NO* reduction. Since
5500 hours is nearly 1 year of operation
(—7000 hours), a catalyst life of 1 year
seems reasonable, based on test results.
In fact, catalyst life may be extended
well beyo'nd 1 year based on the results
of the in-situ regeneration test conducted
at the conclusion of the test program.
These tests showed that catalyst activity
had been restored to the level of
essentially new catalyst. Unfortunately,
since the regeneration test was con-
ducted during the final week of the test
program, it is uncertain how long the
effects of regeneration would last.
Overall, the results of the pilot plant
tests indicate that application of the HZ
process to a coal-fired boiler is tech-
nically feasible. The tests demonstrated
the ability of the process to achieve 90%
NOX reduction for over 90 days and also
demonstrated a stable catalyst life of
nearly 1 year.
Independent Evaluation Test
Program Results
The independent evaluation test
program conducted by Radian had two
primary objectives: to ensure thequality
of the data collected at the HZ pilot plant
and to quantify changes in the concentra-
tions of certain pollutants across the HZ
reactor. Data quality was determined by
quality assurance (QA) audits and
continuous monitor certification tests;
changes in pollutant concentrations
were determined by a secondary emis-
sions sampling program. The results of
each element of the independent
evaluation program are summarized
below.
Quality Assurance Audits
The QA audits conducted by Radian
were designed to ensure that the
process data which are required to
characterize the operation of the HZ
pilot plant were accurate. Radian used
reference methods for auditing process
operating parameters which were
measured on a continuous or routine
basis by Chemico. One exception to this
was the measurement of NH3emissions
which were not routinely monitored by
Chemico, although the original design
of the pilot unit included an analyzer
intended to determine NH3 emissions.
The results of the NH3 emissions
sampling conducted by Radian indi-
cated an average NH3 concentration at
the reactor outlet of about 50 ppm u nder
operating conditions which result in
90% NOx reduction. The NH3 concentra-
tion at the reactor outlet was much
higher than expected (previous work in
Japan indicated NH3 concentrations of
about 10 ppm). The relatively high NH3
concentrations are expected to have an
impact on equipment downstream of
the catalytic reactor for a commercial
application of the HZ process. This is
discussed in more detail later.
The results of the QA audits con-
ducted by Radian are summarized in
Table 1. As shown, all but the SOz
concentration measurements were
within 10% of the values recorded by
Chemico. This indicates that, except for
the S02 monitor, the process data
collected by Chemico accurately charac-
terize the operation of the HZ pilot plant.
In the case of the flue gas SOz con-
centration at the HZ pilot plant, the audit
results were determined to be correct,
and the SOa monitor was in error. This
error is characteristic of the type of SOa
monitor used (pulsed fluorescence)
when the instrument is calibrated with
standard gases composed of SOz in
nitrogen.
Secondary Emissions Sampling
The secondary emissions sampling
program was conducted by Radian
during July and August 1980, concur-
rent with the demonstration test con-
ducted by Chemico. The objective was to
quantify changes in the emission rates
of pollutants other than NOX. For the
most part, these tests were conducted
during tests in which steady state NOx
reduction efficiency was maintained at
90%.
Table 2 summarizes the results of the
secondary emissions sampling program
at the HZ pilot plant. As shown,
concentrations of hydrocarbons, CO,
hydrogen cyanide (HCN), and nitroso-
amines at the reactor outlet were below
the detection limits of the analytical
techniques employed. For hydrocarbons
and CO, no conclusions can be drawn
concerning the impacts of the HZ
process. For HCN, the analytical detec-
tion limit is equivalent to 10 ppbv and for
Table 1. Results of QA Audits at the Hitachi Zosen Pilot Plant
Measurement Audited Relative Error*, %
SOz Concentration
Flue Gas Flowrate
NH3 Injection Rate
Reactor Pressure Drop
Reactor Temperature
a/?/>/af/w> Frmr - Monitor Reading- AuditMeasurement mn%
Audit Measurement
-19.8
- 0.3
- 6.0.
4.5
4.8
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N-Nitrosodimethylamine, 2 ppbv. In
both cases, these concentrations are at
levels which are considered safe for
emission sources.
Table 2 shows an increase in 80s
concentration across the HZ reactor.
This is due to oxidation of SOz in the
reactor and was not unexpected since
the catalyst contains vanadium pent-
oxide which is the catalyst used in
manufacturing sulfuric acid. The ap-
parent change in paniculate concentra-
tion shown in Table 2 is believed to be
due to unaccounted for stratification in
the ducts. Note that no results for
nitrous oxide (N20) are presented. This
is due to the fact that the analytical
technique used to measure N20 was
unsatisfactory for use in a flue gas
stream.
In addition to measuring the con-
centration of particu lates in the flue gas,
an elemental analysis of the particu-
lates was completed in an attempt to de-
termine if erosion of the catalyst has a
measurable effect on the concentration
of vanadium (V) and titanium (Ti) in the
participates. Table 3 gives results of the
elemental analysis of the particu lates
collected at the HZ pilot plant. As
shown, an apparent increase in all ele-
ments occurs across the reactor, but the
relative concentrations on V and Ti re-
main constant. This indicates that there
is no measurable change in the concen-
tration of V or Ti in the particulates
exiting the reactor.
Continuous Monitor
Certification Tests
Certification tests were conducted for
the SC>2 and NOX monitors used to
measure flue gas concentrations of
pollutants at the inlet and outlet of the
reactor. These tests were included in
the independent evaluation program to
ensure the quality of the pilot plant
performance data being collected by
Chemico. Certification of continuous
emission monitors involves a formal
procedure, developed by EPA to ensure
the accuracy of monitors measuring
emissions from sources which must
comply with new source performance
standard emission limitations. For a
continuous emission monitor (CEM) to
be certified, it must be subjected to and
pass a number of performance tests,
including:
• Calibration error.
• Response time.
• Drift.
• Relative accuracy.
Table 2. Stack Sampling Results at HZ Pilot Unit
Flue Gas
Component
Nitrosoamines
(/jg/dscmb)
Hydrogen Cyanide
(mg/dscm)
Ammonia
(ppmv-dry basis)
Sulfur Trioxide
(ppmv-dry basis)
Hydrocarbons* (C, -Ce)
fppmvj
Carbon Monoxide0
Paniculate Loading
Reactor Inlet
Concentration3
5
0.01
Not measured
8.4
1.0
0.017
7.1
Reactor Outlet
Concentration3
5
0.01
54.8
20.7
1.0
O.017
7.7
(g/dscm)
Nitrous Oxide
aAverage of three or more tests.
hdscm - dry standard cubic meter.
c Below the detection limit.
Table 3. Results of Paniculate Analysis at the HZ Pilot Plant3
Component
In
Out
" Concentrations are on a mass fraction basis.
Out/In
Al
Ca
Fe
K
Mg
Mn
Sn
Na
Si
Zn
Cu
Ti
V
10.7%
8200 ppm
4.9%
2.0%
6300 ppm
190 ppm
490 ppm
4200 ppm
18%
190 ppm
150 ppm
5800 ppm
270 ppm
13.0%
9900 ppm
6.0%
2.5%
7800 ppm
240 ppm
680 ppm
4700 ppm
23%
25O ppm
1 70 ppm
6900 ppm
330 ppm
1.21
1.21
1.22
1.25
1.24
1.26
1.40
1.12
1.28
1.32
1.13
1.19
1.22
The performance specifications for each
of the above certification tests are
shown in Table 4, along with results of
the tests. The performance specifica-
tions are those contained in the Federal
Register, Vol. 44, No. 197, Wednesday,
October 10, 1979 - "Proposed Rules:
Standards of Performance for New
Stationary Sources; Continuous Monitor-
ing Performance Specifications".2
As shown in Table 4, the test results
for both the NOX continuous monitors
met the performances specifications.
These data indicate that continuous
monitors were making accurate measure-
ments of flue gas NOX concentrations.
Results of the Conceptual
Design of a 500 MW HZ
Process
A conceptual design of a 500 MW HZ
process was prepared based on the pilot
plant test results. This conceptual
design served as a basis for material and
energy balance calculations and for a
cost estimate for a 500 MW application
of the HZ process.
Table 5 summarizes the results of the
conceptual design for a 500 MW ap-
plication of an HZ process. As shown,
the key design variable levels are
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Table 4. Continuous Monitor Certification Test Results at the HZ Pilot Plant
Certification
Test
Performance
Specification
Inlet /VOx
Monitor
Outlet /VOx
Monitor
Calibration Error
-high level, %
-mid level. %
Response Time, min
Zero Drift (2-hour), %
Calibration Drift
(2-hour), %
Relative Accuracy, %
<5
<5
<2
<2
<20a
1.40
4.39
1.4
1.20
1.93
14.1
4.70
2.68
1.6
0.05
1.78
10.5
aAlternatively, <10 % of the applicable emissions standard.
Table 5. Results of the Conceptual Design for a 500 MW Hitachi Zosen Process
Design Parameter
Design Level
Reactor Design Parameter
Number of Reactors
Reactor Cross Section, m2
Catalyst Volume per Reactor, m3
Reactor System Pressure Drop, kPa
Soot Blowers per Reactor
Soot Blowing Frequency
/ ir Preheater Design Parameters
Soot Blowers per Preheater
Soot Blowing Frequency
Element Configuration
Element Construction
2
96.5
205
1.28
4
3/day
6
6/day
Combined Intermediate and Low
Temperature Zone
Corrosion Resistant Material
in Intermediate and Low Temperature
Zone
presented for the SCR reactor and the
downstream air preheater.
The conceptual design of the HZ
process was prepared for a single
application of the process; it was based
solely on the pilot plant test results.
Results of this design indicate that NOX
emission can be reduced by 90%, using
the HZ process. In fact, 90% NOX reduc-
tion was possible at space velocities
greater than previous estimates in-
dicated (i.e., at a relatively lower catalyst
volume per unit volume of flue gas
treated). However, the greater space
velocities were accompanied by NH3
emissions which were much higher
than previous estimates.
One result of the high NH3 emissions
estimated for the conceptual design
was that special modifications to the air
preheater are required to mitigate
problems associated with the formation
of ammonium sulfates downstream of
the reactor. These modifications were
identified as part of a prior study3; they
are based on Japanese experience with
air preheater operations downstream of
an SCR system. Note that modifications
specified for the air preheater were
expected to minimize problems at
relatively low NH3 and SOs concentra-
tions at the reactor exit. Concentrations
at the reactor outlet for the conceptual
design are much higher than antic-
ipated in previous studies of SCR
technology; this could result in opera-
tional problems which cannot be mini-
mized by the preheater modifications
included in the conceptual design. This
represents an area which requires
further investigation.
Reactor pressure drop and other
design parameters are fairly consistent
with previous estimates for the process.
The design results also show that the
process can operate over a range of
temperatures (340 -. 410°C) and space
velocities (6,500 - 8,900 hr"1) without
any significant effect on NOx reduction
efficiency. This indicates the process
has good flexibility in processing flue
gas under conditions of changing boiler
load.
In summary, the conceptual design
indicates that the HZ process can
reduce NOx emissions by 90%. This NOx
reduction efficiency can be achieved at
a lower catalyst volume per unit of flue
gas treated than previous estimates
indicated. However, the lower catalyst
volume of the conceptual design is
accompanied by a significantly higher
NH3 emission rate which can result in
severe operational problems in down-
stream equipment, particularly the air
preheater. Further work is required to
determine if the effects of these NH3
emissions can be offset by the air
preheater modifications included in the
conceptual design.
Results of Material Balance
Calculations for a 500 MW
HZ Process
Material balance calculations for a
500 MW application of the HZ process
were included as part of this study to
identify raw material requirements for
the process and to serve as a basis for an
estimate of capital investment and
annual revenue requirements. The
material balance was based on the pilot
plant and secondary emissions sam-
pling test results and thus reflects those
results in the estimated raw material
requirements. The most significant
results of the material balance calcula-
tions include estimation of NH3 require-
ments for NO, reduction, NH3 and SOs
emissions from the process, and steam
requirements for air preheater soot
blowing.
The NH3 requirements for the process
were estimated to be 1.0 mole of NH3
per mole of NOX in the flue gas entering
the reactor. This requirement was esti-
mated based on the results of approxi-
mately 6 months of pilot plant operation.
During the 6 months, the NH3/NOX
injection ratio averaged 0.98, and the
NOx reduction efficiency averaged
89.8%. With an NH3/NOX injection ratio
of 1.0, estimated NH3 requirements for
the process decreased about 1O% for
previous estimates.
Estimates of NH3 and SO3 emissions
from the HZ process were significantly
higher than previous estimates in-
dicated. As discussed earlier, this
results in the requirements for air pre-
heater modifications and additional soot
blowing. The requirement for additional
soot blowing results in a sevenfold
increase in HZ process steam require-
ments. This is not very significant from a
material balance standpoint, but it is
important in terms of its effect on
process energy requirements. Note that
HZ claims that the NH3 emission and
S02 oxidation rates can be reducedwith
no decrease in process performance by
adjusting the composition of the cata-
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lyst. However, since this was not
demonstrated during the pilot plant
tests, it was not considered in preparing
the material balances or the conceptual
design.
In summary, the material balance
calculations showed no significant
change in raw material requirements
for the HZ process. The most important
result was the estimated NH3 and SO3
emission rates which were significantly
higher than previous estimates in-
dicated.
Results of Energy Balance
Calculations for a 500 MW
HZ Process
An energy balance was completed as
part of the evaluation of the HZ process.
This energy balance defined overall
process energy requirements and
quantified the heat credits associated
with the process. The results of the
analysis of energy requirements in-
dicated that the HZ process has a net
energy consumption equivalent to
about 0.3% of the energy input to the
boiler.
The individual components of the
overall process energy requirements
are summarized in Table 6. Each
component has been put on the basis of
heat input to the boiler. For steam, a
thermal efficiency of 88% was used to
determine the energy input required to
generate one Gcal of steam energy. For
electricity, a boiler heat rate of 2.27
Mcal/kWh was used. The heat credit
was assumed to replace heat input to
the boiler on a 1-to-1 basis.
Results of the Cost Estimate
for a 500 MW HZ Process
Application
An estimate of total capital investment
and annual revenue requirements for a
500 MW application of the HZ process
was prepared as part of this evaluation.
The estimated costs reflect the results
of the pilot plant tests. When compared
with the previous estimate prepared by
TVA, the modified cost estimates
indicate the magnitude of the impact the
pilot plant results had on estimated
process costs. In addition, comparison
of the modified cost estimate with cost
estimates for other SCR processes
indicates the cost effectiveness of the
HZ process as tested in the pilot plant
program.
Results of Capital Cost Estimate
Table 7 gives the individual compo-
nents of and the estimated total capital
investment for a 500 MW application of
the HZ process. The total capital invest-
ment was estimated to be approxi-
mately $22.1 x 106 which is equivalent
to approximately $44/kW of generating
capacity. When compared to TVA's pre-
vious estimate, this represents a slight
decrease.
The principal difference between thi
two estimates is the estimated catalys
volume. The required catalyst volurm
based on the pilot plant tests wai
estimated to be about 20% less, thereby
decreasing the total capital investment
However, the decrease in costs frort
reduced catalyst volume requirement!
Table 6.
Overall Energy Requirement for a 500 MW Application of the HZ Process
Energy Requirement Percent of Boiler
Energy Area Gcal/hr Capacity
Heat Credit
Steam
Electricity
Total
(3.15)
3.36
3.50
3.71
(0.28)
0.30
0.31
0.33
Table 7. Estimated Capital Investment for a 500 MW Application of the Hitachi
Zosen Process*
Direct Investment*
NHa storage and injection
Reactor section
Gas handling
Air pre heater modifications
Sub-total direct investment (Dl)
Services, utilities (0.06 x Dl)
Total direct investment (TDI)
Indirect Investment
Engineering design and supervision
Architect and engineering contractor
Construction expense
= 0.25 (TDI x 70 "V83
Contractor fees = 0.096 (TDI x JO^f'76
Total indirect investment (IDI)
Contingency ~ 0.2. (TDI + IDI)
Total fixed investment (TFI)
Other Capital Charges
Allowance for start-up and modifications
= (0. 1) (TFI)
Interest during construction
- (0. 12) (TFI)
Total depreciable investment
Land
Working capital
Royalty fee
TOTAL CAPITAL INVESTMENT
Investment, $
645,000
8,632,000
351,000
1,461,000
1 1,089.000
665,000
11,754,000
274,000
69,000
1,933,000
625.000
2,9O1,OOO
2,931,000
17,586,000
1,759,000
2. 1 10,000
21,455,000
5,000
336,000
300,000
22,096,000
%of
Total Direct
Investment
5.5
73.4
3.0
12.4
94.3
5.7
100.00
2.3
0.6
16.4
5.3
24.6
24.9
149.5
15.0
17.9
182.4
2.9
2.6
187.9
"Basis: 500 MW new coal-fired power plant, 3.5% sulfur coal, 90% NO* removal.
Midwest plant location. Represents project beginning mid-1977, ending mid-1980.
Average basis for scaling, mid-1979. Investment requirements for fly ash disposal
excluded. Construction labor shortages with overtime pay incentive not considered.
bEach item of direct investment includes total equipment costs plus installation labor,
and material costs for electrical, piping, ductwork, foundations, structural,
instrumentation, insulation, and site preparation.
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was somewhat offset by the costs of air
preheater modifications required to
minimize ammonium sulfate deposition
problems.
Results of the Annual Revenue
Requirement Estimate
Table 8 gives the individual compo-
nents and the total estimated average
annual revenue requirements for a 500
MW application of the HZ process. The
average annual revenue requirement
was estimated to be approximately
$10.2x 106 which is equivalent to 2.91
mills/kWh. Compared to TVA's previous
estimate, this represents a 17% de-
crease in the annual revenue require-
ments.
As with capital costs, the principal
factor which decreased the annual
revenue requirements is the lower
quantity of catalyst required in the
reactor. Again, this reduction in annual
revenue requirements was somewhat
offset by the cost of increased air
preheater soot blowing.
Cost Comparison and Summary
The capital investment and annual
revenue requirements of the HZ process
have been estimated based on the
results of the test conducted at the EPA-
sponsored pilot plant in Albany, GA.
These estimates indicate that the
capital costs and annual revenue
requirements are slightly lower than the
estimated costs prior to the test program.
A more important comparison, however,
is the cost of the HZ process relative to
the cost of other SCR processes.
Since the same basis was used in
preparing the modified HZ cost estimate
and TVA's preliminary economic esti-
mates for other SCR processes, it is
possible to make a direct comparison
with the costs of the Shell flue gas
treating (SFGT) process which were
developed under the EPA pilot plant test
program. Table 9 gives the estimated
annual revenue requirements for two
pollution control systems which reduce
emissions of particulates, NO,, and
S03 by 99.5, 90, and 90%, respectively.
As shown, the pollution control systems
include flue gas desulfurization capa-
bility and have downstream ESPs to put
the cost estimates on a common basis.
As shown in Table 9, the estimated
costs associated with the HZ processes
are 30 percent lower than those of the
Table 8. Estimated Average Annual Revenue Requirements for a 500 MW Application of the Hitachi Zosen Process*
Item
Direct Costs
Raw materials
Catalyst
Total raw materials
Conversion costs
Operating labor and supervision
Annual
Quantity
5.25 x 106 kg
8760
Unit
Cost, $
0.1 65 /kg
72.507
Annual
Cost, $
866,300
5,125,000
5,991.300
109.500
% of Annual
Revenue Requirec
8.47
50.14
58.61
1.07
Utilities
Steam
Electricity
Heat credit
Maintenance =0.04 x TDI
Analyses
Total conversion costs
Total direct costs
Indirect Costs
Capital charges
Depreciation - (0.06) (total
depreciable investment)
Average cost of capital = (0.086)
(total capital investment)
Overheads
Plant = (0.5) (conversion costs
minus utilities)
Administrative = (0.1)
(operating labor costs)
Total indirect costs
Spent catalyst disposal
Total Annual Revenue Requirements
labor hr
20,700 Gcal
10,787,000 kWh
22,050 Gcal
2,920
labor hr
labor hr
7.94/Gcal
0.029/kWh
-7.94/Gcal
77.007
labor hr
164,400
312,800
(175.100)
470,200
49,600
931,400
6,922,700
1,287,300
1,900.300
314,700
11,000
3,513,300
(214,000)
10.222.000
1.61
3.06
(1-71)
4.60
0.48
9.11
67.72
12.59
18.59
3.08
0.11
34.37
(2.09)
100.00
aBasis: 500 MW new coal-fired power plant, 3.5% S coal. 90 percent NO* reduction, 90 percent SOi removal. Midwest power plant
location. 1980 revenue requirements. Remaining life of power plant = 30 years. Plant on line 7000 hr/yr. Plant heat rate
equals 9.5 Ml/kWh. Investment and revenue requirement for disposal of fly ash excluded. Total direct investment
$11,754,000; total depreciable investment $21,455,OOO; and total capital investment $22.096,000.
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Tabled. Estimated Annual Revenue Requirements for Two Pollution
Control Systems*
SCR Process
Annual Revenue Requirements ($ x 106)
SCR
FGD
ESP
Overall
SFGT
Hitachi Zosen
33.6
10.2
14.7
3.0
2.2
36.6
27.1
"All costs except the HZ-SCR and the SFGT-SCR costs are from "Preliminary Economic
Analysis of NO* Flue Gas Treatment Processes." Tennessee Valley Authority - Office
of Power. EPA-600/7-80-021, February 1980.
SFGT process. These results indicate
that the HZ process, as tested in the pilot
plant and presented in the conceptual
design, is the most economical of the
two SCR processes tested in EPA's pilot
plant program within the constraints of
the conceptual design used in this
study. Note that the relative costs
presented in Table 9 are only valid for
one specific application; they could
change for other applications.
Overall the results of the modified
cost estimate indicate that, for the
particular application examined in this
study, the HZ process is economically
competitive with other SCR processes.
This is based on a conceptual design
which was representative of operating
conditions demonstrated during the
pilot plant tests. Note, however, that the
costs can be affected by the impacts of
high NH3 and S03 emissions whose
effects were not examined during the
pilot plant tests. Additionally, the esti-
mates presented in this evaluation were
based on a 1-year catalyst life which
was not demonstrated. But, HZ will
guarantee a 1 -year catalyst life for coal-
fired applications.
Conclusions
The following conclusions are based
on the work performed during this
study. For the most part, the information
obtained during the course of the study
is summarized in the full report and
serves as backgroundforthe conclusions
presented here. The major conclusions
of this Study are:
• The HZ process can reduce NOX
emissions by 90% when applied to
a coal-fired boiler. This level of
emissions reduction was achieved
over a 90-day period at an NH3/NOX
injection ratio of 1.0 and space
velocities greater than previous
test work indicated. However, the
excellent performance of this pilot
plant was accompanied by NH3
emissions which were much higher
than previous estimates indicated.
The initial tests of the HZ process
experienced problems with catalyst
plugging which resulted in failure
of two charges of NOXNON 500
series catalyst. These problems
were eliminated by using NOXNON
600 series catalyst (a catalyst with
larger gas passages) and com-
pressed air (as opposed to super-
heated steam) for reactor soot
blowing. It appears likely that the
good performance of the NOXNON
600 catalyst was due to the larger
gas passages since the fly ash has
a tendency to agglomerate in dry
environments.
A gradual decline in catalyst
activity was recorded during the
test program which resulted in the
requirement for increased NH3/
NOx injection ratios to attain 90%
NO, reduction. Because the test
program was terminated after
5500 hours of operation, the
catalyst activity after 1 year of
operation could not be determined.
> A novel, in situ catalyst regenera-
tion technique was tested as part
of the program. This test showed
that the regenerated catalyst had
activity similar to fresh catalyst
and thus reversed some of the
decline in activity observed during
the test program. Unfortunately,
the catalyst regeneration technique
was tested toward the end of the
pilot plant test program; so it is
uncertain how long the effects of
the catalyst regeneration will last.
> The independent evaluation test
program indicated that emission
rates of most pollutants were not
affected by-the HZ process. How-
ever, emission rates of both NH3
and S03 were relatively high and
can result in operational problems
in the downstream equipment. The
severity of any problems in this
regard is very site specific and
could not be assessed as part of
this study. This should, however.
be given careful consideration in
any planned applications of the HZ
process.
• The conceptual design and material
balance calculations indicated high
NH3 emission rates which will
cause severe operational problems
in the air preheater, downstream
of the HZ process. The conceptual
design included air preheater
modifications designed to minimize
those problems. But because the
estimated NHs and SOs emission
rates are much higher than pre-
vious estimates, it is uncertain if
the air preheater modifications will
be adequate. Further investigation
in this area is required.
• The overall energy requirements
for the HZ process were estimated
to be 0.3% of the boiler's capacity.
This is a very small fraction of
boiler capacity and does not signifi-
cantly affect process costs.
• The estimated capital investment
and annual revenue requirements
for the HZ process were slightly
lower than TVA's preliminary
estimate. This indicates that the
HZ process is economically com-
petitive with other SCR processes
when considered for application to
a coal-fired boiler. Note that the
cost estimates assumed a 1-year
catalyst life which was not dem-
onstrated during the pilot plant
tests, although it would be guar-
anteed by HZ. The relative process
costs would change if a 1-year
catalyst life were not possible.
In conclusion, the pilot plant tests
indicate the HZ process is technically
suited for application to coal-fired
sources. However, the tests did not
demonstrate a 1 -year catalyst life which
is generally considered a minimum for
technical feasibility of an SCR process.
In reality, a shorter catalyst life would
translate into increased annual revenue
requirements. In terms of costs, under
the conditions of the cost estimate
prepared as part of this study, the HZ
process is economically competitive
with other SCR processes.
References
1. Maxwell, J.D., et al. Preliminary
Economic Analysis of NOx Flue
Gas Treatment Processes. EPA-
600/7-80-021 (NTISPB 80-176456).
February 1980.
2. Environmental Protection Agency.
40 CFR Part 60. Standards of Per-
formance for New Stationary
-------
Sources: Continuous Monitoring
Performance Specifications - Pro-
posed Revisions. Federal Register/
Vol. 44, No. 197/Wednesday,
October 10, 1979/Proposed Rules.
Burke, J.M. and K.L. Johnson. Am-
monium Sulfate and Bisulfate
Formation in Air Preheaters. EPA-
600/7-82-025a. April 1982.
J. M. Burke is with Radian Corporation, Austin. TX 78759.
J. David Mobley is the EPA Project Officer (see below).
The complete report, entitled "Hitachi Zosen /VOX Flue Gas Treatment Process:
Volume2. Independent Evaluation," (Order No. PB 83-113 837; Cost: $19.OO,
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:
Industrial Environmental Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
U. S. GOVERNMENT PRINTING OFFICE: 1983/6551-095/589
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