HomeMy WebLinkAboutSP 144B; SDG&E Wastewater Facility; Specific Plan (SP) (12)I
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FIRST ANNUAL REPORT
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Presented by
San Diego Gas & Electric
NOVEMBER 22, 1977
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In compliance with City of Carlsbad Ordinance 9456,
• Section 314(k), San Diego Gas & Electric is submitting this
first annual report to the Carlsbad City Council. This
• report will describe improvements in plant and operating
tt procedures during the preceding year which reduce the emission
of air pollutants resulting from the operation of Encina
I Units 1, 2, 3 and 4.
The following are areas of improvement that were
If accomplished in the last year. These improvements result
• in increased efficiency, reduced fuel consumption, and a
corresponding decrease in emissions.
• I. Major Turbine Overhaul
Encina Units 1 and 3 underwent major turbine over-
| hauls in September 1976 and January 1977, respectively (see
« Attachments 1 and 2). During a major overhaul, the entire
turbine is dismantled, useable parts are cleaned and worn
I parts replaced or repaired. The turbine is then reassembled
and put back in operation. The goal of a major overhaul is
jj to return the turbine efficiency to as close to design level
— as possible and to insure reliable operation for the next
™ four years. Major turbine overhauls are normally done every
II four years.
II. Boiler Overhaul
I The boilers for Units 1, 2, 3 and 4 were overhauled
_ during the past year. By cleaning and repairing burners, air
• registers, heat transfer surfaces and structural components,
• air leakage is minimized. In this way, boiler efficiency is
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I returned to design conditions.
• III. Condenser Tube Scraping
The tubes in the condenser of all four units were
• scraped to remove marine growth and other deposits. In
ft this process, spring loaded metal scrapers are inserted into
the 1-inch tubes (each condenser has 6,000 to 10,000 tubes)
• and a high pressure water stream pushes the scrapers through
the individual tubes. Condenser heat transfer is thus
improved, reducing each unit's turbine back pressure. This
• results in improved unit efficiency.
IV. Electric Production Performance Monitoring Program
I Since mid-1975, a special SDG&E team has been
working to find new ways of improving plant efficiency and
| to cut fuel oil consumption. The Performance Monitoring
_ Program is one of several developments that resulted from
™ those efforts,
flj The aim of this program is to provide a method of
monitoring performance of each unit so that it can be
| operated at its most efficient level under various loading
_ conditions. This increased efficiency leads to reduced oil
™ consumption and corresponding emission reduction. Operators
• make hourly comparisons of actual unit performance to the
best attainable standards and then take corrective action
| when appropriate. The operator can either adjust the
_ control setting of the unit or request that maintenance be
™ performed (see Attachment 3).
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V. Encina Fallout Test Program
| Since mid- 197 6, SDG&E has been conducting this
^ program to determine and correct the cause of damage resulting
• from acidic particulate emissions from Encina Power Plant.
• The test program had its beginnings in June 1976,
at which time SDG&E accepted the allegations and provisions
• of the Abatement Petition sought by the Air Pollution Control
District. At that time it was established by both SDG&E
» and the APCD that "SDG&E was responsible for at least some
• of the corrosive spotting" around the Encina Power Plant.
We subsequently hired an independent consultant, York
I Research Corporation, as specified in the Abatement Order,
to conduct a comprehensive study to determine the source of
I the damaging particles , and develop a method to control
• these particles.
Results of the test program and recommendations
• for acid-fallout abatement at Encina are as follows:
1. Reaffirming our original findings, the four
I boilers situated at Encina Power Plant do
M contribute to local corrosive spotting problems.
Acidified particles formed in the boilers
I are emitted, and some have sufficient weight
to fall within close proximity of the plant
| and cause damage if they land on a susceptible
_ surface such as a car, or a patio awning. The
™ majority of particles emitted from the unit are
• extremely small, dust-like, and non-corrosive
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in nature. The acidic fallout particles are
I very few in number and small in size.
™ 2. Acid fallout particles are composed of two key
• parts, a carrier called a "cenosphere," and an
acid. The cenosphere is a carbon particle
£ formed during the combustion of oil, which
looks and acts like a sponge. It has an affinity
• for liquids, so the many holes in its structure
• become filled with water and acid formed during
combustion. As combustion efficiency increases,
• production of cenospheres decreases. Therefore,
efforts to improve combustion efficiency are
• extremely worthwhile. Sulfuric acid is formed
I when a small fraction of sulfur in the fuel
combines with oxygen during combustion and
• then with water formed from combustion or
available in the atmosphere. When a particle
• lands on a cloth, painted, or metal surface,
•j the acid is strong enough to corrode or stain
the surface. Fortunately, the acid-fallout
• particles are small and few in number so that
the damage caused is not extensive.i
• 3. Fallout damage was determined to be primarily
caused by acidic particles and not by iron
ft rust, as was originally speculated.
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4. The majority of acid-fallout emitted occurs
I during and immediately after each unit's soot
• blow, an operation to clean the heat transfer
surfaces of the boiler. However, fallout is
• emitted from each boiler at varying levels
throughout the day.
« 5. Local meteorological conditions surrounding
Encina Power Plant are such that the impact of
• fallout cannot be accurately forecasted based
on surface wind speed and direction information.
£ This is because an unpredictable upper-air
_ layer exists above approximately 250 feet
• altitude that has no relationship with the
• surface wind conditions. When the stack plumes
enter this layer, the problem of determining
• fallout impact and intensity are complicated.
• Based on these findings and York's recommendations,
• SDG&E implemented the following control measures to sub-
stantially eliminate the damaging acidic fallout from the
• Encina Power Plant:
1. Magnesium based fuel oil additive is being
• injected into the fuel system of each boiler
• at Encina on a continuous basis. All Encina
boilers have been using an additive since
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May 6, 1977. Test data based on ambient fallout
• monitoring devices indicates a typical monthly
average reduction exceeds 95% in the number of
m acidic particles emitted from the power plant.
• The additive reduces acid-fallout by both
inhibiting the formation of 803, and thus sulfuric
• acid, and by neutralizing any acid that is formed.
The rate of additive injection will be
| maintained at a level just sufficient to
^ substantially reduce acid-fallout, which will
™ then minimize any increase in particulates
• from the boilers. With the additive, we are
currently in compliance with Rule 52 which
• sets the maximum source particulate levels at
_ 0.1 grains/SCF.
• 2. Soot blowing on each boiler has been rescheduled
from present 5:00 p,m. start time to 11:00 a.m.
• in order to take advantage of favorable wind
conditions existing from mid-day through early
W afternoon. Surface winds during this period
• are generally at or near their maximum speed
with high persistence and apparently, from
• ambient emission data, the upper winds tend to
follow the surface winds during this time period.
• This has the effect of limiting the dispersion
m of fallout to a narrow corridor, east to south-east
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of the plant, which is essentially unpopulated.
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3. Automatic fuel oil viscosity controls will be
" installed on each boiler to assure that oil
• combustion is optimized so as to reduce the
carbonaceous acid carriers, "cenospheres . "
• Combustion equipment is designed to operate
at certain fuel oil viscosities in order to
• produce the best flame possible and minimize
• the amount of unburned carbon. This project
is currently in the engineering phase, with
• two consultants handling the engineering. The
current schedule calls for completion of the
I project in 1979.
Based on the trends exhibited by the data during
• limited test periods, the first two control methods, addi-
tives and soot blow changes will provide the Encina Power
| Plant with substantial elimination of damaging fallout
• while installation of viscosity controls will just enhance
the effectiveness of the other control methods. The cost
H of these control methods will amount to about $30,000 per
month for the purchase of the fuel oil additive.
| At the recommendation of the San Diego Air
• Pollution Control Officer, a new test program was initiated
to study the proposed solution to the fallout program. This
• test program will continue until December 31, 1977.
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The following activities are underway as part of
P this new test program:
_ 1. At the request of the State Department of Health,
™ tests are being conducted to assess if any adverse
• side effects may result from use of the additive.
SDG&E has initiated a program to determine
£ emission and dispersive characteristics of
respirable-sized particles, with qualitative and
• quantitative identification. Information will
• be submitted to APCD and the Department of Health.
• 2. SDG&E and APCD are jointly conducting a series
of source tests on each boiler to determine any
• net increase or decrease in particulate emissions.
• APCD Rules 20.1, 20.2, 53 (b) and Subpart A of
Regulation X limit an increase of total particu-
• late emissions to 10 Ib/hr or 100 Ib/hr, as
compared to emission levels prior to any modifi-
• cation of operations or equipment.
In conclusion, SDG&E has an aggressive and efficient
• overhaul and maintenance program to maintain the most
efficient power plants possible. Additionally, we have
I been successful in finding new ways to improve plant eff ici-
• ency in many areas.
Regarding the Fallout Abatement Program, SDG&E
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began over a year ago to solve a problem others had not
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— solved, and sought to find a solution others had not yet
• found. All valid claims made by residents affected by
tt this problem have been acknowledged and settled. Through
an extensive test program utilizing York Research Corp.,
P and an expenditure to date of $1,620,000, we have developed
— a Control Plan that will substantially eliminate the fallout
™ problem. Evidence of this is the fact that demand claims by
• Carlsbad residents have dropped dramatically. We are con-
tinuing our testing through December 1977 to verify that in
• fact this Control Plan will meet all applicable regulatory
standards.
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ELECTRIC PRODUCTION DEPARTMENT
1976 OVERHAUL SCHEDULE REVISION 'C
JANUARY
5 1O 15 2O 25
ooo
a<o
MARCH
5 IO 15 2O 25 5 IO 15 2O 25 5 10 15 2O 25 5 IO 15 2O 25 5 IO 15 2O 25 5 IO 15 2O 25 5 IO 15 2O 25 5 1O 15 2O 25 5 IO 15 2O 25 S IO 15 2O 25
ooo
•5 IO 15 2O 25
JANUARY
5 1O 15 2O 25 5 IO 15 2O 25
FEBRUARY MARCH
5 1O 15 2O 25
APRIL
5 IO 15 2O 25
MAY
5 IO 15 2O 25
JUNE
5 IO 15 20 25
JULY
5 10 15 ?O 25
AUGUST
5 1O 15 2O 25
SEPTEMBER
5 IO 15 2O 25
OCTOBER
5 IO 15 2O 25
NOVEMBER
5 IO 15 2O 25
DECEMBER
ATTACHMENT 2
GENERATING UNIT OVERHAUL SCHEDULE
1977, REVISION 'D'
CAPACITY RESOURCES (Mw)
NUCLEAR UNIT SCHEDULED MAINTENANCE (Mw)
GAS TURBINE TEMPERATURE DERATING (Mw)
LARGEST CONTINGENCY (Mw)
CAPACITY BEFORE SCHEDULED MAINT. (Mw)
PREDICTED MONTHLY PEAK DEMAND (Mw)
ALLOWANCE FOR EXTREME WEATHER (Mw)
EXTREME MONTHLY PEAK DEMAND (Mw)
MARGIN BEFORE SCHEDULED MAINT. (Mw)
MAINT WEEK STARTS ON (SUNDAY)
CAPACITY SCHEDULED OFF (Mw)
UNIT
MARGIN AFTER SCHEDULED MAINT. (Mw)
JANUARY
2248
86
287
1875
1626
85
1711
164
2 9 16 23
102 102 102
EA3 EA3 EA3
164 62 62 62
FEBRUARY
2249
86
287
1876
1560
83
1643
233
30 6 13 20
102 102 102
EA3 EA3 EA3
131 131 131 233
MARCH
2257
86
287
1884
1543
66
1609
275
27 6 13 20 27
102 102 102 102
EA2 EA2 EA2 EA2
173 173 173 173 275
APRIL
2257
43
287
1927
1509
78
1587
340
3 10 17 24
142 142 220 220
SB2 SB2 SB4 SB4
198 198 120 120
MAY
2257 2257
43 43
287 220
1927 1994
1438 1438
98 98
1536 1536
391 458
1 8 15 22
287 287
EA4 EA4
391 171 171 391
JUNE
2255
34
287
1934
1617
146
1763
171
29 5 12 19 26
64 64 64 38
SG4 SG4SG3SG1
171 107 107 107 133
CAPACITY RESOURCES (Mw)
NUCLEAR UNIT SCHEDULED MAINTENANCE (Mw)
GAS TURBINE TEMPERATURE DERATING (Mw)
LARGEST CONTINGENCY (Mw)
CAPACITY BEFORE SCHEDULED MAINT. (Mw)
PREDICTED MONTHLY PEAK DEMAND (Mw)
ALLOWANCE FOR EXTREME WEATHER (Mw)
EXTREME MONTHLY PEAK DEMAND (Mw)
MARGIN BEFORE SCHEDULED MAINT. (Mw)
MAINT. WEEK STARTS ON (SUNDAY)
CAPACITY SCHEDULED OFF (Mw)
UNIT
MARGIN AFTER SCHEDULED MAINT. (Mw)
JULY
2252
40
287
1925
1707
65
1772
153
3 10 17 24
100 100 100
EA1 EA1 EA1
53 53 53 153
AUGUST
2187
42
287
1858
1797
114
1911
•53
31 7 14 21 28
-53 -53 -53 -53 -53
SEPTEMBER
2185
76
287
1822
1761
210
1971
-149
4 11 18 25
-149-149-149 -149
OCTOBER
2185
67
287
1831
1603
125
1728
103
2 9 16 23
198 198 198 198
SB3 SB3 SB3 SB3
-95 -95 -95 -95
NOVEMBER
2185
3
287
1895
1638
83
1721
174
30 6 13 20 27
198 198 198 198
SB3 SB3 SB3 SB3
-24 -24 -24 -24 174
DECEMBER
2187
287
1900
1724
86
1810
90
4 11 18 25
140 140
SB1 SB1
90 -50 -50 90
NOTES: CAPACITY RESOURCES BASED ON FIGURES
SHOWN IN "CALIFORNIA POWER POOL LOAD
RESOURCES REPORT" DATED 5/4/77.
MONTHLY PEAK DEMAND BASED ON FIGURES
SHOWN IN "LONG TERM DEMAND FORE-
CAST" - 5/5/77.
UNIT
ENCINA4
ENCINA3
ENCINA2
ENCINA 1
SOUTH BAY 4
SOUTH BAY 3
SOUTH BAY 2
SOUTH BAY 1
SILVER GATE 4
SILVER GATE 3
SILVER GATE 2
SILVER GATE 1
STATION B 25
STATION B 24
STATION B 22
STATION B 21
STATION B HT
GAS TURBINES
CAPACITY
287
102
102
100
220
198
142
140
64
64
64
38
41
28
18
17
3
410
ATTACHMENT 3
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EFFICIENCY IMPROVEMENT PROGRAM AT SAN DIEGO GAS & ELECTRIC
Presented at: EEI Prime Movers Committee Meeting
October 4, 1976
by: Jon P. Hardway
General Superintendent, Electric Production
San Diego Gas & Electric Company
INTRODUCTION
Over the last year and a half, San Diego Gas & Electric
Company has been concentrating on reducing its single largest
operating expense—the cost of power plant fuel and purchased
energy. A special team was set up to increase plant efficiency
and to cut fuel oil consumption. According to 1974 data, SDG&E's
system heat rate of 10945 Btu/kwhr ranked 70th in the survey of
the Top 100 electric utilities. In 1975 we achieved a heat rate
of 10481 Btu/kwhr which elevated us to 41st among the Top 100.
That improvement of 29 steps is significant. It was exceeded
only by one other company--Middle South Utilities, which ranked
56th in 1974 and 23rd in 1975.
SDG&E's improvement in heat rate reduced operating
expense in 1975 by approximately $7 million which, undoubtedly,
had a significant effect in the Company's improved financial
outlook.
Just what did we do to achieve this savings? Many
factors contributed, including a unit performance monitoring pro-
gram, improved maintenance, cleaner condensers, and operational
dispatch changes.
PERFORMANCE MONITORING
Our first approach to improve unit efficiencies was to
develop a unit performance monitoring program, similar to Florida
Power and Light's Energy Management Program.2 Special thanks go
to Charlie Branning of FP&L and Joe Davis of Duke Power Company
for their helpful assistance.
1. "The Top 100 Electric Utilities 1974--A Year of Zero Growth",
Electric Light & Power. July 21, 1975 (1974 Data); August 16,
1976 (1975 Data).
2. "An Energy Management Program Helps This Utility Reduce Its
Fuel Bill", 1975 Generation Planbook, Power Magazine, p. 41-45
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-2-
The aim of our program is to provide a method of
monitoring performance of each unit, so that it can be operated
at its best efficiency under various loading conditions.
Five key variables were selected as potentially having
the greatest effect on heat rate. They are-.
1) Turbine back pressure, as a function of circulating
water inlet temperatures.
2) Excess oxygen at the economizer outlet.
3) Air heater gas out temperature, as a function of
air heater air in temperature.
4) Main steam temperature, and
5) Reheat steam temperature.
A display chart containing these five variables, (as a
function of Mw), for each generating unit has been placed in each
plant control room. The charts graphically depict the "best
attainable" performance standards so that the operator can
evaluate the unit's performance. The best attainable approach was
selected over design parameters to encourage operators to meet
present realistic goals. Each operator makes hourly comparisons
of actual performance to the best attainable standards and then
takes corrective action when appropriate. The operator can either
adjust the control setting of the unit or request that maintenance
be performed.
The operator then records actual operating performance
on control room logs which are processed and compared by a digital
computer to the best attainable standards. The difference between
the actual measurement and the best attainable value is then used
to calculate the influence on heat rate and a prediction of the
theoretical fuel savings (loss) that is created by variance from
optimum. Knowing the economic impact of the increased fuel costs,
our engineers can then use the data to determine the best correc-
tive action, such as optimum frequency and method of condenser
cleaning, boiler wash, soot blowing and other maintenance item
scheduling.
The computer program summarizes daily and monthly values
for the performance monitoring report. See Figure 1 for sample
monthly printout, and Figure 2 for trend analysis.
The performance monitoring report provides Company
management with information on efficient plant operation. But
just ay important - it requires the plant operators to participate
directly in monitoring each unit's efficiency.
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-3-
OPERATIONAL CHANGES
Operational changes have had a significant effect on
our system heat rate improvement. Our first step was to set up
an accurate set of current incremental heat rate characteristics
for all steam generating units. In some cases, we had previously
been dispatching units on the basis of 10-year-old data. Since
absolute heat rate changes can change the incremental heat rates
significantly, accurate input-output tests are essential. A
special team of SDG&E engineers was formed to make periodic tests
of all steam generating units. Within 15 months, tests of every
steam unit on the system had been completed. The results were
twofold: First, accurate incremental heat rate curves were defined,
and second, each unit's performance was compared to original or
manufacture specifications.
The incremental heat rate curves were then utilized
by a new computer program, "Unit Commitment/Pro duct ion Cost".
This program provides load dispatchers with an hour-by-hour
model of our electric generating system. Now, the Load Supervisor
can efficiently dispatch our generating units by considering
incremental heat rates plus important plant operating conditions
such as boiler/turbine startup, shutdown, and other operation data.
This new computer program also enables our Electric
Operations Department to more effectively schedule limited
use of less efficient, quick-starting gas turbines.
MAINTENANCE
Our input-output testing program pointed out that some
units no longer met the original manufacturer's guarantee. Thus,
it became our goal on each unit's yearly overhaul to return our
boiler/turbines to an "as new" condition. This goal, of course,
could not be achieved on every unit without significant modifi-
cations and expense.
During 1975, several major unit overhauls corrected
problems such as severe deposits on turbine blades, circulating
pump impeller wear, turbine seal "rubout", and a condenser
fouling.
Another key maintenance development was a new computerized
overhaul scheduling program. This program determines the optimum
yearly schedule for overhauling each generating unit, thereby
minimizing the system fuel cost and maximizing the system heat
rate improvement.
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-4-
CONDENSERS
Both the Performance Monitoring Program and our main-
tenance programs concentrate on turbine back pressure as the
most important variable influencing heat rates. Efforts in 1975
have significantly reduced each unit's back pressure. Our goal,
in this case, is to reduce all units back pressure to the
original manufacturer design specification.
In the past, we cleaned our condensers each month with
an air and water method, and each year with rubber plugs. However,
these techniques cleaned primarily tube-sheet debris and did not
remove mineral deposits. As indicated on Figure 3, the back
pressure on our South Bay Unit 1 had been increasing since 1960.
Stemming from our heat rate improvement program, we looked into
different methods of condenser tube cleaning. We evaluated
hydroblast (10,000 psi waterjet), acid cleaning, a "flocculent"
material, plus the metal scraper technique. The metal scraper
approach, provided by the Condenser Cleaners Manufacturing Co.,
Pittsburgh, Pennsylvania, was judged to be the superior method.
The condenser tube wear was empirically determined to be less
than 0.06 thousandths of an inch (.00006 inch) for each scraping.
The results were dramatic!
We flushed out more than one ton of "crud" from the
condenser cleaning operation at South Bay Unit 1. The deposits
were analyzed to be iron oxide, manganese oxide, silica, and
organic growth. Figure 3 shows a 1.10" Hg improvement in back
pressure — a return to original design back pressure.
Our experience with the scrapers in 1976 indicated that,
considering our specific fouling conditions and heat rate economics,
a frequency of twice a year is optimum for our South Bay units and
once per year for our Encina units. By cleaning condensers on
seven units, we have lowered our system heat rate by 0.6670, gaining
a fuel saving of more than $1.2 million per year.
SUMMARY
I have described some of the major parts of our program
to reduce the net system heat rate. Many other factors contributed
to improvement, but perhaps the most significant is the sincere
interest our management has shown in heat rate improvement.
We're still learning about efficiency projects, but we
were encouraged by the first year results. Our goal for 1976 is to
improve efficiency by an additional 1 to 3%. For this second stage
efficiency effort we have retained the NUS Corporation of Rockville,
Maryland as consulting engineers. This will put additional emphasis
on specific programs that should further improve our position in
the Top 100 electric utilities.