control of combustion turbine particulate emissions...

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Control of Combustion Turbine

Particulate Emissions Verified

by Improved Measurement Technology

M. J. AMBROSE

Senior Engineer, Plant Development Engineering, Combustion Turbine Systems Div., Mem.ASME

E. S. OBIDINSKI

Senior Engineer

J.H. MARLOW

Advanced Engineer Steam Turbine Generator, Materials Engineering Lab., Technical Operations Div.

Westinghouse Electric Corp., Lester, Pa.

Early field tests on 25- and 33-MW combustion turbines indicated that. with modest controls on fuel sulfur content, compliance with strict regulations on particulate emissions, such as the 10 lb (4.5 kg) per hour Rule 67 of the Los Angeles Air Pollution Control District, wasfeasible. This paper describes the field development program to demonstrate Rule 67 compliance on an 80-MW combustion turbine for which the 10-lb/hr (4.5-kg/hr) limit is approximately 4 psm by weight. Particulate controls were implemented by installing improved-smoke combustors, and using water injection and low sulfur fuel . Meticulous sampling and analytical procedures were developed, using a specially designed and equipped environmental test laboratory trailer, to study the properties of particulate collection filters, and to improve the precision of measurements from each portion of the particulate sampling system: probe, filter, and water impingers. The test results clearly indicate that with proper attention to the details of sample system preconditioning, sample collection and analysis, the large combustion turbine can comply with the stringent 10-lb/hr (4.5-kg/hr) particulate limit of Rule 67.

Contributed by the Gas Turbine Division of The American Society of Mechanical Engineers for presentation at the Gas Turbine Conference & Exhibit & Solar Energy Conference, San Diego, Calif., March 12-15, 1979. Manuscript received at ASME Headquarters January II, 1'79.

Copies will be available until December I, 1979.

. THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS, UNITED ENGINEERING CENTER, 345 EAST 47th STREET, NEW YORK, N.Y. 10017 "'ol ...

Copyright © 1979 by ASME

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Control of Combustion Turbine

Particulate Emissions Verified

by Improved Measurement Technology

M. J. AMBROSE E. S. OBIDINSKI

ABSTRACT

Early field tests on 25 and 33 MW combustion turbines indicated that, with modest controls on fuel sulfur content, compliance with strict regulations on particulate emissions, such as the 10 pounds (4.5 kilograms) per hour Rule 67 of the Los Angeles Air Pollution Control District, was feasible.

This paper describes the field development program to demonstrate Rule 67 compliance on an 80 MW combustion turbine for which the 10 lb/hr (4.5 kg/hr) limit is approximately 4 parts per million by weight. Particulate controls were implemented by installing improved-smoke combustors, and using wahar injection and low sulfur fuel. Meticulous sampling and analytical procedures were developed, using a specially-d�signed and equipped environmental test laboratory trailer, to study the properties of particulate collection filters, and to improve the precision of measurements from each portion of the particulate sampling system : probe, filter and water impingers.

The test results clearly indicate that with proper attention to the details of sample system preconditioning, sample collection and analysis, the large combustion turbine can comply with the stringent 10 lb/hr (4.5 kg/hr) particulate limit of Rule 67.

1

J. H. MARLOW 111 111111111111 J�f J)li�i�l lif liii� 111111111111 11

10001675983

INTRODUCTION

In the early 1970s, environmental concern in the Southern California area had become sufficiently strong that the then Air Pollution Control District of Los Angeles County (LAAPCD) issued additional stringent regulations to protect the local air quality. Among these newer air pollution regulations was Rule 67 (1), which limited emissions from stationary sources to :

10 pounds per hour (lb/hr) combustion contaminants (4.5 kg/hr)

140 lb/hr nitrogen oxides (NOx), expressed as NOZ (613.6 kg/hr)

200 lb/hr sulfur oxides {SOx), expressed as SOz (90.9 kg/hr)

Sensitive to the needs of electric utilities in the Southern California region for additional combustion turbine systems, Westinghouse Combustion Turbine Systems Division (CTSD) undertook a program to implement emissions controls capable of meeting the requirements of Rule 67. NOx controls by a patented(2) combustor water injection system were developed during laboratory test programs (3), and verified by full field demonstrations on a 33 MW combustion turbineC4), Particulate emissions were evaluated


during field operations for information as to their character and source (4), (5), (6), and emissions controls were specified, developed and implemented during field test programs to demonstrate the capability of these combustion turbines to meet the stringent emission limits of Rule 67 (4,5) .

This paper describes the particulate state-of-theart and the f ield development program recently conducted at Florida Power Corporation (FPC) to demonstrate the capability of Rule 67 compliance with larger and more efficient 80 MW combustion turbines, for which the 10 lb/hr (4.5 kg/hr) particulate limit is approximately 4 parts per million by weight (ppm wt).

80 MW DATA COMPARED WITH EARLY FIELD TEST RESULTS

Early baseline particulate data had been obtained during extensive tests on a 25 MW combustion turbine located at the Gilbert Station of Jersey Central Power & Light (5, 6) . With standard #2 GT f uel, base load particulate loadings were 9.61 lb/hr (4.37 kg/hr) which is equivalent to slightly less than 8 ppm wt for this size turbine. Due to the

awkwardness of performing ppm-level measurements using the water impinger portion of the LAAPCD sampling procedure (7), this baseline data had both wide scatter, + 2 lb/hr (+ 0.91 kg/hr), equivalent to + '1 . 6 ppm wt at the 9 . Gl lb/hr (4. 37 kg/hr) level, and significant water impinger residue, 3 lb/hr (1.4 kg/hr), equivalent to 2.4 ppm wt downstream of the primary collection f ilter (5).

In order to qualify the larger 80 MW combustion turbine under the 10 lb/hr (4 . 5 kg/hr) limit of Rule 67, baseline particulate levels would require approximately 50% reduction to slightly less than 4 ppm wt. Furthermore, analytical procedures for particulate determinations would require extensive ref inement to improve the precision and accuracy of measurements at such low emission levels.

With the combination of improved-smoke combustors, water-injection, and low-sulfur fuel, the 80 MW turbine has demonstrated an average net LA/SCAQMD particulate level of 9 . 07 lb/hr (4 . 12 kg/hr), equivalent to 3 . 5 ppm wt, at base load. Analytical precision of particulate measurements has been refined to provide repeatability as follows :

1st LOW-SULFUR FUEL TEST

REPLICATE LOWSULFUR FUEL TEST DIFFERENCE

Average Exhaust Filtered Particulate

Average Exhaust Water Impinger Chargeable Residue

Net LAAPCD/ SCAQMD Particulate

PARTICULATE SAMPLING SYSTEM

7.57 lb/hr (3. 44 kg/hr) 2 . 86 ppm wt

2.31 lb/hr ( 1 . 05 kg/hr) 0 . 87 ppm wt

9.15 lb/hr (4.16 kg/hr) 3.45 ppm wt

The sampling system specified for collecting particulates in Los Angeles and vicinity is shown schematically in Figure i. Particulates are determined by direct f iltration at 200 F (93 C) followed by water impingement, which is equivalent to LAAPCD method 4 . 4.2 (7), and which was initially developed during procedural discussions with LAAPCD in 1972. The procedure is also essentially the same as South Coast Air Quality Management District (SCAQUD) "Modified EPA Method 5" (8) .

The LAAPCD and SCAQMD net particulate charge consists of :

(1) All total weight collected in the exhaust sampling probe by rinsing with distilled water . (Particulate probes should be removed from the exhaust as soon as possible after sampling . )

Plus :

(2) All total weight collected on the 200 F (93 C) sample f ilter determined after drying at 110 c.

Plus :

(3) All total weight collected in the water impingers and determined as a dried (110 C) residue.

2

8 . 42 lb/hr (3.83 kg/hr) 3 . 1 8 ppm wt

1.24 lb/hr (0. 56 kg/hr) 0.47 ppm wt

8.99 lb/hr (4.09 kg/hr) 3.39 ppm wt

Minus :

0 . 85 lb/hr (O. 39 kg/hr) 0 . 32 ppm wt

1 . 07 lb/hr (0 . 49 kg/hr) 0 . 40 ppm wt

0 . 16 lb/hr (0.07 kg/hr) 0 . 06 ppm wt

(4) All artifact H2S04 • 2 H20, which has been formed by S02 absorption during water impingement sample collection, and retained in the dried water impinger residue . This allowance for artifact H2S04' • 2 H20 i� in accordance with both LAAPCD method 4 . 4 . 1 . 1(7J and the SCAQMD Modified EPA Method 5 (8). It is noted that "true" sulfuric acid mist is efficiently collected on the 200 F (93 C) filter which is upstream of the water impingers .

Minus:

(5) All particulate material determined by similar measurements at the compressor inlet of the combustion turbine .

EMISSIONS CONTROL DEMONSTRATION - 80 MW COMBUSTION TURBINE

In January, 1975, Westinghouse CTSD and Florida Power Corporation (FPC) agreed to cooperate in an emissions control demonstration program on the 80 MW combustion turbines at the Turner Plant, Enterprise, Florida. The objectives of the emissions program were :

A. To confirm emission levels which had been projected on the basis of tests on 25 and 33 MW turbines .


1. Isokinetic Particulate Probe, Length as appropriate for 12-point sampling traverse

2. 4 7 .. millimeter Glass Fiber Filter {Type "A") in Stainless Steel Holder

3. Oven/Heater to maintain 200 F (93 C) Filter Temperature

4. Thermocouple , Filter Inlet Gas Temperature 5. Thermocouple, Filter Outlet Gas Temperature 6. Greenburg-Smith Impinger with 200 milliliters

Distilled Water 7 . Greenburg-Smith Impinger without any Impingement

Fluid 8. Thermometer 9. Ice Bath Container

10. Mercury Manometer 11. Dry Gas Volume Meter 12. Vacuum Pump with Flow Control

Fig. 1 Schematic of LAAPCD and SCAQMD Sampling System For Particulates

B. To verify NOx reduction with combustor water injection , which had initially been demonstrated on the 33 MW turbine.

C. To verify the composition of particulates from this larger engine.

D. To verify particulate reduction with low-sulfur fuel.

�. To determine the baseline smoke level of an improved-smoke combustor.

SITE AND TURBINE PREPARATIONS

A. A set of improved-smoke combustors was supplied and installed during overhaul of one of the engines. The earlier smoke performance of these combustors was expected to result in improved particulate levels.

B. Several site alterations were accomplished in preparation for extensive emissions testing , as shown schematically in Figures #2 and #3 :

(1) Installation of a water-forwarding system (forwarding pumps, a 3" (76 mm) pipeline and an 8 , 000 gallon (30.3 cubic meter) recirculation tanker) to supply boiler condensate for combustor water injection.

(2) Installation of an exhaust stack sampling platform and an array of gas and particulate sampling probes for multi-point exhaust sampling in the exhaust silencer section where the flow path is long and straigh�.

EXHAUST SA .. PLING STATION

ENVIRON .. ENTAL TEST TRAILER

Fig. 2 Schematic of General Test Arrangement

1500 FEET OF 3'" PIPE ABOVE GROUND TO

COMBUSTION TURBINE

LEVEt.. CONTROL

8,000 GALLON TANKER

WATER RESERVOIR

RESERVOIR ANO SKID TIE·IN

STATE HlGHWAY

WATER INJECTION SKID r--------------1 I I

\1 TO

COMBUSTION TURBINE

NOZZLES

Fig. 3 Schematic of Water Injection System

3


(3) Cleaning of the 10,000 gallon (37.9 m]) fuel day-tank, and partially filling it with a sufficient amount of low sulfur fuel blend to permit replicate particulate testing.

(4) Installation of Combustion Turbine Environmental Test Laboratory Trailer #721 at the exhaust stack, to support complete, on-site analyses of emission gases and particulates, as well as of fuel and injection wateT.

IMPROVEMENTS IN TECHNIQUES OF SAMPLE COLLECTION, HANDLING AND ANALYSIS

Prior to controlled-emissions testing with combustor water injection, particulate samples were collected for the purposes of developing improved and more sensitive procedures, In October, 1975, the first full exhaust traverse for particulates was performed with the reference procedureC7,8) used on earlier tests.

These initial tests indicated the need to improve the techniques of sample collection, handling and analysis to avoid formation of what were considered artifact particulates, and thereby restrict the total particulate charge to true levels. Consequently the following procedural changes were made in subsequent tests:

A. Avoidance of intermittent shut-down and subsequent resumption of particulate sampling.

B. Preheating the filters and holders prior to sampling.

C. High-temperature thermal conditioning of particulate collection filters and tare-weight beakers and flasks, to stabilize tare and sample weights and to eliminate potential effects of moistureretention.

D. Use of commercial distilled water for impingement sampling, probe washing, and sample transfer, and testing water blanks for solids content.

E. Use of teflon sleeves, rather than stop-cock grease, to seal the ground-glass joints of the water impingers.

F. Direct transfer of probe wash and water impinger samples from large collection beakers to tareweight beakers and flasks, avoiding intermediate sample handling and transfeT.

G. Use of lightest possible tare-weight beakers and flasks.

TAl!LE I PA.cTICULATe LUAOINGS, SERIES FILTERS - uEC. 1975

Dl\Y/Dl\TE

Til'.F.

EX?.ACST LOC . ' PROBE LENGTH (FEET)

TOTAL EXRl\UST PAllTI!=. lST FILTER

TOTl\L EXRl\UST PAJITIC. 2�m FILTER

TOTAL F.Xi!AUf;T PARTIC. �RD f'lLTrP

H2 504 li;T FILTF.R

"2 �n4 2110 l'ILTF.R

"2 504 3RD FILTER

Fuel Sulfur Content

DAY/01\TE

TIMF.

F.XHl\UST LOCATION

TOTAL EXHAUST rARTIC. l5T FILTEll

TOTAL EXHAUST PARTIC. 2ND FILTER TOTAL EXHAUST PARTIC. 3RD FILTP.R

"2 so4 lST FILTl:R

R2 SC14 2ND FILTER

"2 504 3RD FILTER

Fuel Sulfur Content

DAY/DATE

TI!'-�

EXl!l\UST LOCATION

TOTAL EXHAUST PARTIC. lST FILTER

TOTAL F.Xlll\UST PARTIC. 2ND FILTER

TOTl\L F.XHAUnT PARTIC. 3RD l"IJ,TEll

", so, lST FIJ,TP.R

R2 so4 2ND l"!L'f'F.R e7 so, 3RD FILTER

Fuel Sulfur Content

4

(LB/llR) (LD/llR) (T.n/l'R) (LO/fill) (LB/llR) (LB/llR)

(% wt)

(LB/HR) '.LB/1111)

(LO/llR) (LD/llR) (LD/llR) (LB/UR)

(% wt)

(J,D/HR) (Lii/HR) (Ln/!'11) (J,B/1111) cr.n/rtlll (LD/llR) (% wt)

N-5 Olli l"J.l\ PC, F.t:'!'ERPt\ISE • CTl4 (BASt: LOAD, STATION FUEL, NO WATP.R IN.JF:C'l'ION)

SATURDAY, DP.CEMOJ:R 6, lq75 l2:U 16:27 12:37 12:28 13:00 l4: 18 17:33 1-7' 2-7' 3-7' �-7' 2-7' (��) 1-'7' 2-7' 5. 32 . 6.74 7.42 3.59 2. 70 5.99 6.63 0.37 0.75 -0.20 0.30 -0.27 0 l. 20 0.15 0.37 -0.40 -0.30 0 0.15 -0.60 1.27 0.75 1.80 l.19 1.35 3.67 3.0l

0.30 1.12 0.60 0.45 o.�o o. 67 o. 75 0.60 0.97 0.80 -0.45 0.67 0.45 0.30

0.080

SUNDAY, DECEMLEn 7, 11:33 11:53 11:37 11:57 12:00

1975 12:14 13:43

2-4' 2-7' 2-10• 3-4' 3-R.�KE 2-4' (SLOI>

FLOl'I) l. 96 8.07 o. 23 0.98

7.01 10.63 6.�3 6.1.8 2.34 0.53 -0.20 0.38 0.15 0.90

0.38 0.60 0.3R 0 0.53 o. 83 0.60 0.38 5.20 2.49 2.ll 0.67 0.98 J.01 0.90 1.20 0.53 0.59 0.30 0.23 1.13 0.53 0.23 0.53 0.59 0.30 O.ll 0.67

,0.084

SUNDAY 12/7/75 15:07 14:20 3-7' 3-10'

(SLOW FLOW)

1.81 3.01 0.23 0.45 0.23 0.45 0.67 O.RJ 0.38 0.45 0.23 0.45

- 0.084-

14:01 13:34 15:00 J-1°<1> 4-7' ._,,��) 6.74 3.22 3.15

2.32 0.30 0.45 1.80 -0.30 0.60 2.02 l.12 1.05 l.�2 0.30 0.90 o. 67 0.44 1.65

13:59 13:50 14:09 2-7°(1) 2-10' 3-4 o(l)

8.97 7.H 6.86 l.20 0.60 3.09

0.83 0 2.49 1.28 2.49 2.49 0.07 l . 28 1.20 o. 23 0.23 0.60

(1) Warmer filters (260 - 275°F) than standard 200°F


H. Improved sensitivity analysis of artifact H2S04 • 2 H20 which forms a relatively large and non-chargeable background for water impingement particulate collection.

I. Meticulous care in sample processing using an on-site laboratory trailer to minimize sample handling and to eliminate storage and shipping, thereby avoiding uncertainties of sample integrity.

CONFIRMATION OF PARTICULATE FILTRATION EFFICIENCY

In late 1975, development tests were conducted to confirm particulate filtration efficiency and particulate compositional analysis techniques:

A. Condensation Nuclei Monitor (CNM) data taken immediately downstream of several primary particulate collection f ilters (item 2 Figure 1) indicated essentially 1007. f iltration efficiency (9). No significant solid particles, or liquid droplets, which could act as particulate nuclei during rapid expansion in a supersaturated detector cell, were found after filtering the exhaust with the type "A" glass fiber particulate collectors. The filtered deposits remained stable below 275 F (135 C).

B. Encouraged by the results of this CNH/filter efficiency experiment, and implementing the improved particulate collection procedures, follow-on tests were performed with series filters as an independent confirmation of their collection efficiency. Successful demonstration of filtration efficiency might eventually justify elimination of the cumbersome water impinger collection system.

ARTIFACT PARTICULATE OBSERVATIONS USING SERIES FILTERS

Table 1 summarizes the results of the evaluation of the properties of type "A" glass fiber particulate filters, using a series arrangement. The primary (first) particulate filter served as the collector for solid particles (carbon, ash, H2S04 acid mist). Downstream filters did accumulate a small but consistent amount of collected weight, essentially all of which was eventually analyzed as H2S04 within the limits of analytical precision at these low levels. Half the downstream filters were analyzed for H2S04 by precipitation techniques, and half by baking. Titrimetric deterninations of f ilter H2S04 were attempted, but found to be inadequate at these low values of H2S04 retained on the series filters.

Three of the series filter tests were conducted at temperatures sufficiently high (260 - 275 F,

127-135 C) to have permitted some H2S04 to migrate through the primary f ilter in the vapor phase. As shown in Table 1, these resulted in noticeably higher deposits on the downstream filters. It is postulated that the H2S04 weight retained on the great majority of downstream filters is due to S02 gas-phase absorption, a phenomenon noticed by other investigators involved in ambient-air particulate collection (10, 11, 12, 13J. This tendency of particulate collection f ilters to retain a fraction of S02 gas might be considered as a system bias, inflating the particulate charge an average 0.85 lb/hr (0.39 kg/hr). However, no corrections for this apparent filter artifact have been made to the results presented herein as "LAAPCD/SCAQHD" particulate loadings.

During compositional baking analysis of several of the primary, or first, particulate filter samples, an interesting correlation (Figure 4) was observed between filtered HzS04 and filtered carbon. Baking to 675 F (357 C) releases the H2S04, and further bcl ing to 950 F (510 C) volatilizes all the carbon.

It is postulated that the carbon particulate acts as an adsorbent for the exhaust sulfur species, retaining an equilibrated relative amount regardless of the total amount of filtered particulate. Further bench test investigations were performed to develop an understanding of this sulfur-carbon interaction (9) Results indicate that this phenomenon is unlikely to occur at normal filtration temperatures.

PRC-CONDITIONING THE PARTICULATE SAMPLING SYSTEM

Pre-conditioning The Particulate Probes

All equipment and hardware used in particulate collection is cleaned and conditioned prior to its use in the analytical scheme.

The fittings on the isokinetic probes are checked for tightness, and the probe-tip thermocouple is checked to conf irm its functioning ability at operating temperatures. Both ends of the probe are then uncapped, and several flushing solutions are forced through the probe to condition the sampling surface prior to its exposure to combustion products.

Ca:tREl..ATION OF FILTER HzS04 AND C&Reo,,.

W !.Ollll fl"C GY• !BASE lOAO 'liflO W&TC!t IH.(Cf'OM!i

zo

,, ,,

, , ,,

,

,, ,

10

••

Fig. 4 Correlation of Filter HzS04 and Carbon.

The probe pre-conditioning is performed by using the arrangement shown in Figure 5 and a pump capable of producing 10 pounds per square inch (PSIG),equivalent to 0.7 kilograms per square centimeter (kg/cm3) on the system.

After pre-conditioning, the probe is removed from the cleaning system, leak checked, and capped at both ends. The probe is maintained in this sealed condition until ready for positioning in an exhaust sampling stream, when the caps are removed in order to connect the sampling train and to position the probe in the stack for sample collection.

5


ISOKINETIC PROBE

PARTICUUTt Pi!OBE CLEANING SYSTEM

l6'ie§§�§:=?: i=J PROBE WASHING

ADAPTER

Fig . 5 Schematic of Particulate Probe Cleaning System

Pre-Conditioning The Particulate Filters

A sufficient amount of "as received" glass fiber type "A" filters to complete the desired sample station requirements are weighed, and then placed in a muffle f urnace for at least one hour to stabilize the filters at a temperature higher than any to which the filter will be exposed during sampling and subsequent analysis . The filters are removed and placed in a drying desiccator until ambient equilibrium is reached . The filters are then reweighed and these tare weights are recorded . The filters are f inally assembled into a pre-conditioned stainless steel f ilter holder .

Pre-Conditioning The Particulate Filter Holders

The apparatus used in collecting the solid particulate contaminants is conditioned and treated prior to sampling, and will be located upstream of the "water impinger" collecting section when both are used . (Figure 1).

Each stainless steel filter holder is inspected for defects which may lead to improper sampling during the collection period . The inlet and outlet thermocouples attached to the filter holder are checked to ensure proper functioning during sampling . The holder is reassembled with a previously conditioned f ilter and leak checked . Ilolh ends are

6

then capped until used in a sampling train system .

Pre-Conditioning The Water Impingers

If the water impinger section is to be used in stack particulate sampling (7 , 8), then each impinger is inspected for defects in wall structure prior to sampling . The impingers are then rinsed clean with a dilute acid solution followed by several rinses with distilled wate� . When it is determined that the impingers are sufficiently clean, they are then air dried . All connecting devices (Tygon and black rubber tubing) are inspected and cleaned in a similar manne� . Teflon sleeves are placed in the base of each impinger and all train connections made, taking care to ensure the integrity of the connector tubing . After a leak check, the inlet and exhaust ends of each impinger train are connected to each other to ensure protection from foreign contaminants prior to collection of particulates . All portions of the particulate contaminant collection train (probe, dry particle f ilter, and water impinger sections) are now ready to be positioned at an exhaust sampling station .

Pre-Conditioning The Tare-Weight Flasks For Water Impinger/Probe Wash Collection

The glassware used for the final reduction of the dried residues from the probe washings and the

water impingement collection is similarly pre-conditioned . The small flasks are identified, cleaned with dilute acid solution, rinsed with distilled water, and placed in a muffle furnace for one hour at a stabilization temperature sufficiently higher than any to which the flasks will be exposed during subsequent analysis . The flasks are removed, placed in a drying desiccator until ambient equilibrium is reached, then reweighed and the weights recorded . They are next placed in a drying oven at 110 C for one hour, removed, cooled and weighed, and these tare weights are recorded . The flasks, if not to be used immediately, are returned to the drying oven, When needed, the cooling and tare-weighing procedures are repeated .

PROBE SAMPLING AND WATER WASHING

At the end of the sampling period, the particu�ate collection train is disassembled frora the prob� . The probe is removed from the stack as soon as possible, and both ends capped until the probe is cool enough for water washin•g. When the probe has cooled suf ficiently, it is uncapped, and distilled water is added and allowed to absorb any particulate contaminants for several minutes, then transferred to a large, clean collection beaker . This water wash procedure is repeated until it is determined that the combustion emission contaminants are completely removed from the sampling probe . All washings are retained in suitable clean containers for subsequent volume reduction and analysis .

The cleaning-flushing assembly (Figure 5) is reconnected to the probe and the flushing solutions are passed through until the probe has been reconditioned . The train is then disassembled , and the probe is capped at both ends, now ready for future sampling .

ANALYSES OF PARTICULATE CONTAMINANTS

The total loading and composition analyses of the particulate contaminants in the probe, filter and water impinger samples are conducted in the following manner:

�. The probe wash sample, collected in a previously cleaned beaker, is placed on a hot plate and slowly reduced until the majority of the probe wash water has been evaporated . The condensed sample is removed and allowed to coo•! . The cooled volume is transferred to a preconditioned tare-weighted flask with a minimum of distilled water washings and then placed in a drying oven at 110 C until reduced to dryness . The flask is cooled to ambient conditions and weighed. The weight obtained is used to calculate the total probe wash particulate contaminant. The sample is then analyzed further using titration, precipitation, baking or atomic absorption analytical techniques, depending on the amount of detailed composition information required .

B . After the f ilter holder has cooled, the filter is removed and weighed, and the result recorded as the "as received" weigh'!: . The "as received" filter is placed in a drying oven at 110 C for one hour, removed, cooled and reweighed . The weight is used to calculate the filter particulate contaminant loading . The filter is then analyzed by titration, precipitation, baking or atomic absorption techniques, depending on the amount of additional composition information desired .


C . The water impinger particulate contaminant sample, prior to volume reduction, is analyzed for final condensate volume, pH and specific conductance . The liquid volume sample is transferred to a previously cleaned beaker, placed on a hot plate and slowly reduced until the majority of the water impinger sample has been evaporatetl . The sample beaker is removed and cooled, and the remaining concentrated volume is transferred to a preconditioned, tare-weighted flask used for final reduction and analysis . The f lask is placed in a drying oven at 110 C and the sample volume evaporated to dryness . The flask is removed, cooled and weighed. The residue weight is used to calculate the total particulate plus H2S04 • 2 H20 artifact contaminant in the water impinger portion of the sampling train . The artifact content of the flask must be further analyzed to enable a determination of chargeable particulate loading from the water impinger residue .

Correction for the water impinger artifact H2S04' • 2 HzO (from S02 absorption) is permissible (7,8), since the upstream particulate filter efficiently collects any acid mist when maintained at 200 F (913.3 0). Artifact acid analysis can be performed by titration, precipitation or baking techniques, dependent on the amount of additional composition information required .

WATER INJECTION EMISSIONS TESTS

After completing the above investigations and procedural developments for improved p�rticulate measurement technology, the program was redirected towards the demonstration of emissions control . The water injection system was activated in May 1976, and baseline tests were performed the following month to confirm the reductions in smoke and nitrogen oxides (NOx), and to determ,.ne the effect on carbon monoxide (CO).

The reduction in exhaust smoke, as measured by ASTM-D-2156, with water injection at peak and base loads is shown in Figures 6 and '7. Not:e in Figure 7 that the overall smoke level eventually observed with the low sulfur demonstration fuel is significantly less than for station #2 GT distillate fuel .

Exhaust NOx was measured both by on-line electrochemical cell instrumentation and by wet chemistry (Phenoldisulfonic (PSD) acid method ANSI/ASTM-D-1608, and a modification of the Saltzman technique ASTM-D-1607 . ) These three methods normally agree within a :t_ 10 parts per million by volume (ppmv) band of data. The reduction in NOx with water injection at peak and base loads is shown in Figures 8 and 9. Rule 67 NOx compliance for this size turbine is equivalent to 32 pprn'IT .

Exhaust CO was monitored during the water injection tests by an on-line Non-dispersive Infrared Analyzer (NDlR'), CO was observed to increase with water injection at both peak and base loads, as shown in Figures 10 and 11 .

PARTICULATE DISTRIBUTION WITHIN THE EXHAUST

Two complete data sets of particulate distribution within the exhaust appear in Tables 2 and •3 .

These are replicate tests from the final demonstration of Rule 67 particulate compliance with low-sulfur fuel and water injection

Cocplete LAAPCD/SCAQMD particulate train samples were taken at each equally spaced position of a twelvepoint exhaust traverse . The samples were taken at 3 foot (0.9 m) depth intervals in four locations .

.l.STM-D-2156 SMOKE·SPOT

NUMBER

PEAK LOAD SMOKE REDUCTION WITH WATER INJECTION (W�Oll FPC GT4)

(STATlDN FUEL •z GT)

Fig . 6 Peak Load Smoke Reduction With Water Injection

BASE LDAO SMOKE REOUC!ION WITH WATER INJECTI� IW50IB FPC GT41 (tf.l.TION FUEL •ZGT, ANO LOW SULFUA FUEL BUNP)

ASTM·D�21)& SMOKE SPOT HUWSER

(STATION FU£l. •ZGT) •

- --Oo (LDW·S FUELJ

� � � � � m � � � � � � WATER IN.IECTtON FL.OW (GAL.LONS/ MINUTE}

Fig, 7 Base Load Smoke Reduction With Water Injection and Low-Sulfur Fuel

The particulate portion of each component of the sampling system is shown in Tables 2 and 3. The accumulated particulate charge as described above is shown as "Net Particulate Including Probe Wash" .

Exhaust Filter Results

There were high exhaust particulate loadings on two

7


(WSOIB FPC GT4)

E F FECT OF WATER INJECTION ON PEAK LOAD NOx

NO• (PPMV)

•MODIFIED SALTZMAN IASTN�0-1607)

X PDS ( ANSl/ASTM·D•l&D8l oFARISTOR 220

20D

180

160

140

120

100

80

60

40

20

10 20 30 40 50 60 70 8 0 90 100 110 I 0 WATER INJECTION FLOW( GALLONS/MINUTE)

Fig. 8 Peak Load NOx Reduction With Water Injection

EFFECT OF WATER INJECTION ON BASE LOAD NO• (W·501B F PC GT41

NOx (PPMVI

220

200

180

160

140

120

100

80

60

• MODIFIED SALTZMAN (ASTM ·D·l607)

X PDS (ANS1/ASTM·D·l608)

o FA RISTOR

0 0 10 20 30 40 50 60 70 80 90 100 110 120

WATER INJECTION FLOW (GALLONS I MINUTE)

Fig. 9 Base Load NOx Reduction With Water Injection

IW-5018 FPC GT4) EFFECT OF WATER INJECTION ON PEAK LOAD CO

CO (NOIRI PPMV 220

200

180

160

140

120

100

80

60

40

20

o+-��,--.-�..--.-�..-....,....�.--...--... O 10 20 30 40 SO 60 70 80 90 100 110 I 0

WATER INJECTION FLOW I GALLO NS I MINUTE)

Fig. 10 Effect of Water Injection on Peak Load CO

8

gFEtT OF 'A'ATEH UUECTION ON BASE LOAD CO tW�OIB FPC Gl 4)

� w � � � � ro � � � � ® WATER INJECTION fLO# (GALLONS/MNiJTtl

Fig. 11 Effect of Water Injection On Base Load CO

filters for each test (line 4 of Tables 2 & 3). These were associated with unusually high ash deposits during the first test and unusually high H2S04 retention during the second test.

Despite these few anomalous results, the average exhaust filter particulate loadings for these replication tests were 7.57 and 8. 42 lb/hr (3.44 and 3.33 kg/hr). This is considered excellent agreement, within 0.9 lb/hr (0.41 kg/hr) which is slightly more than 0. 3 ppm wt.

Exhaust Water Impinger Chargeable Particulate Residue

As described above, the chargeable particulate residue from water impingement collection is the difference between the impinger total collected weight and the artifact H2S04 • 2 H20 contained therein.

Lines 5 and 6 of Tables 2 and 3 illustrate these values for the replicate tests for which the average exhaust chargeable particulate residues are 2.31 and 1.25 lb/hr (1.05 and 0.56 kg/hr). Two analytical methods for H2so4 • 2 H20 were used on both sets of samples. The agreement is again excellent, within 1.1 lb/hr (0.5 kg/hr) which is slightly more than 0.4 ppm wt

Probe Wash Results

The exhaust probe washings for the first test had been combined, averaged, and corrected for inlet results, producing an average net probe wash particulate loading of 1.1 lb/hr (0.5 kg/hr), as shown on line 14 of Table 2.

The individual exhaust probe wash results for the second test are shown in line 7 of Table 3. Their 2.25 lb/hr (1.02 kg/hr) average value, when corrected for the 1.15 lb/hr (0.52 kg/hr) inlet probe wash total weight (line 12) , provides a net probe wash loading identical to the first test, 1.1 lb/hr (0.5 kg/hr).


10

11

12

13

14

15

9

10

11

12

13

TABLE #2 W501B FLORIDA POWER CORP,, TURNER STATION GT#4

LAAPCD & SCAQMD PARTICULATE DATA 90 GPM WATER INJlCTION FOR NOx CONTROL

LOW-SULFUR FUEL FOR PARTICULATE CONTROL

(5) Day-Datc-Fuel-C. T. Load Hode Sunda7, August 8, 1976, Low Sulfur Fuel, 8aae Load {Titration and J!aking Comparison for H2S04 Analysis)

Gas Turbine Load BASE

(4) Partlc.Probe Location 1-l' 1-6' 1-91 2-3' 2-6' 2-9' l-3' 3-6' l-9' 4-3' 4-6'

b.h.Partlc.Pilter Total vt Lb/Hr s.11 8.94 7.15 12.93 5.46 6.06 7.29 7.16 5.50 3.75 6.13 Exh.Partic.Water lm\l.Total wt. Lb/Hr 7.90 5.91 5.33 8.05 10.04 8.98 7 .66 7.39 lC.28 8.40 8.05 Exh.Partic.Wate.r Imp. H2S04•2Hz0(3) Lb/Hr 6.2!11 5.0�l) 2.9,1>' 5.W 8.1lu 1.16ll 2.•P> 5.6!2> 8.9!1> 5.6�2> 6.9!1>

E:ith.Partic.Probe Wash Total vt. Lb/Ur llASHINGS COKllINED • AVEllAGED..

Exh. Portie. (4+5-6) Lb/Hr 6.79 9.76 9.49 15.44 6.79 7. 74 12.08 e.94 6.83 6.55 7.24 Inlet Filter Total vt.. Lb/Hr Inlet Water Imp.Total vt Lb/Hr Inlet Water bop. HzS04·2Hzo131 Lb/Hr Inlet Probe Wash Total vt. Lb/Hr

(4) 4-9'

15.29

10.49

4.9P>

20.83

!zh . Avs. Inlet llet

: 1.57

8.21

J 2. 31 lb/hr difference

5.90 chargeable 1.1

9.88

1.17

2.21

1.H

is

Net hrtlc. (B-9-U>+ll) Lb/Hr 4.96 7,93 7.66 13.61 4.96 5.91 10.25 7.11 5.00 4,72 5.41 19.0 e.05 Avg. Het Probe Wa11h Lb/Ur WASHlNCS COKllINED • AVERAGED Hct Partic.Incl.Probe Wash Lb/Hr

(exhauat-inlct)

H2�04 • 2�z0 Ana�y1ill B� ��!::ion

6.06

Artllact HzS04 • 2Hz0 In \later Impinger•

9.0J 8. 76 14.71 6.06 1.01 11.35 e.n

(1) (2) (3) (4) High Filter \il'eighu Acolociated With Uau11uallJ HJ1b A.h Depoait

(5) Fuel Sulfur Conteat • 0.07 Z wt

1A8LE 3 W501B FLORIDA POWER CORP,, TIJRNER STATION GTl4

LMPCD � SCAQtm PARTICULATE DATA 90 CPH WATER INJF.CTIOH FOR llOx CONTROL

LOW-SULt1JR FUEL FOR PARTICULAT� CONTROL

6.10 5.82 6.51 10.1

Day-Date-Fuel-G.T. Load Hode Sunday, Sept., 12, 1976, Low·Sulfur Fuel�)Base Load (Titration and liaking Comparison For u2so4 Analysis)

Caa Turbine Load BASE l!xh.

1;1

9.15

Partic. Probe Location 1-31 1-91 2-3'41 2-6' 2-9' 3-314> 3-6' 3-9' 4-3' 4-6' 4-9' Avg. Inlet

Exh. Parttc. Filter Total wt:. Lb/Hr 5.28 7.25 6.84 16.64 8.39 8.24 18.91 5.63 5.78 4.06 6.34 7.74 8.42

Exh. Partic. Water

Net

Imp. Total vt Lb/Hr 9.12 34.8 7.77 6.14 9.00 7.62 5.94 10.18 8.63 7.28 9.40 29.99 12.l

Jl.24 lo/hr

(2) (2) (1) (1) (2) (2) (1) {l) (2) (1) (2) (l) difference is I1111>.Hzso4.2H2o(3) Lb/Hr 6.89 33.8 6.46 6.67 6.54 5.78 5.79 10.34 7.08 7.28 5.47 28.99 10.92 chargeable Exh. Partic. Water

Exh. Probe Wash Total wt. Lb/Hr 0.92 1. 70 1.84 2. 76 2.38 0.92 4.88 2.31 2.54 3.22 2.39 1.15 2.25

Exh. Par tic. (4+5-6+7) Lb/Hr 8.43 9.95 9.99 18.87 13.23 11.0 23.94. 7. 78 9.87 7.28 12.66 9.89 11.91

Inlet Filter Total vt. Lb/Hr 0.46

Inlet Water Imp. Total wt. Lb/Hr 2.77

Inlet Water Imp. H2S04·2H:z0 (3) Lb/Hr 1.46

Inlet Probe Wash Total vt. Lb/Hr 1.15

Net Partic. Incl. Probe Waah Lb/Hr 5.51 7.03 1.01 15.95 10.31 8.08 21.02 4.86 6.95 4.36 9. 74 6.97 8.99 (Exhaust-Inlet) (0-9-lo+ll-12)

(1) Hz;:c>4 . ZH�O �lyai11 �y Baking (2) Titration (3) Artifact H2504 • 2H20 in Water Iapingera ( 4) High Filter Weights Aaaociated With Unusually High H2S04 Collections. (5) Fuel Sulfur Content • 0.07 % vt

9


Net LAAPCD/SCAQMD Particulate Charge

The net particulate charge including exhaust filters, water impingers, probe washings, and corrections for inlet samples and all artifact H2S04 • 2 H20, is shown in lines 15 and 13 of Tables 2 and 3, respectively. The agreement between both low-sulfur fuel test results, 9.15 and 8.99 lb/hr (4.16 and 4.09 kg/hr), indicates excellent overall repeatability.

OVERALL EFFECT OF FUEL·SULFUR ON LAAPCD/SCAQMD PARTICULATES

During this demonstration of particulate control with low sulfur fuel, six (6) different water injection tests were performed with fuel sulfur content ranging from 0.07 to 0.17% by weight.

The first four tests were performed with station #2 GT distillate fuel to obtain an exhaust baseline using the improved particulate measurement technologies described above. The low-sulfur fuel was a blended fuel specially-procured for particulate testing. Table 4 summarizes the average values of the exhaust particulate traverses as well as the inlet values and the final LAAPCD/SCAQMD net particulate charge (line 14).

Several techniques of H2S04 • 2 H20 analysis were used in the determination of water impinger non-chargeable artifact (line 5 of Table 4), all but one of which correlates well with the total collected sample weight of the water impinger. The average water impinger chargeable residue, which is the difference between lines 4 and 5, is only 3 lb/hr (1.4 kg/hr), which is approximately 1 ppm wt.

The 3rd test (July 19th), which was perturbed by a water injection trip out and restart, resulted in the highest particulate loading, noted in the water impinger charge.

Average inlet particulate values have been used to calculate the net results for the second test (July 15th), which was terminated by a turbine shutdown prior to collecting all samples. The average net probe wash particulate value from the last two llow-sulfur) tests has been used to calculate the results for the first 4 tests, which were performed primarily to obtain an exhaust baseline.

The overall correlation of LAAPCD/SCAQMD particulate levels with fuel sulfur is shown in Figure 12, which displays the ability of the large low-sMoke 80 MW combustion turbine to satisfy the 10 lb/hr (�.S kg/hr) limit of Rule 67 by operating with water injection and controlled-sulfur fuel.

CONCLUSIONS

�arge combustion turbine systems with low-smoke combustors, water injection and low sulfur fuel, can comply with the stringent 10 lb/hr (4.5 kg/hr) particulate limit of LAAPCD Rule 67 with proper attention to the details of sample system preconditioning, sample collection and analysis.

Particulate levels decrease noticeably with lower fuel sulfur.

Further smoke reductions have been achieved with combustor water injection, observed on earlier testsC4), and by the use of low sulfur fuel.

Water injection produces the expected dramatic reduction in NOx emissions, also observed on earlier testsC4)

TABLE 4

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

11.

12.

13.

14.

10

W501B FLORIDA POWER CORP., nJRHER STATION CT h EFFECT OF PUE!. SULFUR CONTENT OH LMPCD ' SCAQKD PARTICULATE l!lHSSlOHS

WE LOAD. 90 CPH I/ATER INJECTION FOR llOx CONTROL

Date (1976) JULY 13 JULY 15 JULY 19 (l)

Fuel Sulfur l vt 0.12 0.17 0.16

Avg. Exh. Part1c. Filter Total vt. lb/hr 10.80 9.88 8.25

Avg. !.xh. Partic:. Water Imp. Total vt. lb/hr 16.94 7.80 12.40

Avg. Exh . Partlc. \later lap. e2so4 • 29z0Ul lb/hr H.67(3) 3.43(4) 3.91 (4)

Avg. Exh. Partic. Probe WHh Tot.al vt. lb/hr flot pert orme.d (6)

Avg. Exh. Partic. (3)+(4) - (5)+(6) Total �. lb/hr 14.07 14.25 16. 74

Inlet Filter Total wt. lb/hr -0.29 0.416<8> l.03

Inlet Water lap. Total vt. lb/hr 10.66 3.62 (8) 0.52

lnlet Water Iap. 82504 • 2e20<2> lb/hr 2.66 l.85<8> 3.12

Inlet Probe Wo.ah Tctal vt. lb/hr ot performed (E)

Het Partic. • (7-8-9+111-11) lb/hr 6.36 12.06 18.31

Avg. Net Probe Wash lb/hr --- Uoe l. l lb/hr from 8/8 and 9/ll

Net Partic. Including 1.1 • lb/hr 7.46 lb/hr Probe Wash (8/8. 9/12)

(l) Water injection tripped end waa restored durina teat (2) Artifact H2S04 • 2H20 in water 1.mpingere (3) Analysis of 1.mpinger HzS04 • 2H20 by baking technique (4) " 11 " " " 11 precipitation technique (S) 11 titration technique (6) Adding 1.1 lb/hr net probe wash (8/8, 9/12) (7) Exhaust probe vaehlnga combined and corrected for inlet value

13.16 19.41

(8) Inlet data not taken. due to turbine trip; used average inlet data fro• 7/13 through 9/12

JULY JO

o.u

9.20

17.12

13.17(3,5)

13.a

-o.29

l.94

0.44

11.915

13.05

AUG. 8 Sl!PT. 12

0.07 0.01

7.57 8.42

1.21 12.16

5.90CJ.5> 10.92(3,5)

(7) 2.25

9.88 11.91

1.17 0.46

2.21 2. 77

l.55 1.46

(7) 1.15

8.99


E FFECT OF FUEL SULFUR CONTENT ON L A A PCO I SCAOMO NET PARTICULATES

LAAPCD ISCAOMO NET PAR T ICULATES

( L B IH R I

20

15

10

(W- �01 9 FPC GT4 BASE LOAD ) WITH 90 GPM WATER INJECTION

�E:N

bNJECTION TRIP"' RESTART

• L

UNUSUALLY HIGH INLET PARTICULATE LOADING

g,+-�� 0 05 10 15 20 FUEL SULFUR CONTENT (% WEIGHTI

Fig . 12 Effect of Fuel Sulfur Content On Particulates

Carbon monoxide increases measureably with combustor water injection .

The particulate filter is essentially 100% efficient , which may justify elimination of the cumbersome water impinger collection system .

Particulate filters appear to be biased by a small amount of H2S04 weight , which we postulate originates from absorption of gas-phase S02 .

The correlation between f iltered carbon and sulfur as H2S04 postulates an adsorption of the H2S04 on carbon. This phenomenon is unlikely to occur at normal particulate collection temperature .

ACKNOWLEDGEMENTS

The authors wish to express appreciation to the following individuals from Florida Power Corporation who participated in the planning and execution of these emissions tests :

Mr . James Whitehurst - Manager, Turner Plant , FPC

Mr . Charles Fadeley - Supervisor, Operations , Turner Plant , FPC

Mr . Jerry Campbell - Combustion Turbine Supervisor , Turner Plant , FPC

Mr . Dan Shantz - Environmental Engineer , FPC Corporate Staff

Further acknowledgement is made of the following lndividuals from the Westinghouse Research and Development Center who assisted both in the planning and execution of the particulate development program :

Mr . William Hickam - Manager , Physical Chemistry

Dr . Gerry Carlson - Manager , Analytical Chemistry

Appreciation is also extended to Mr . Chester A. Jersey, of the Westinghouse CTSD Engineering Department , who directed the site preparations and turbine alterations, and who provided the vital interface between utility operations and engineering test requirements .

REFERENCES

1 . Air Pollution Rules and Regulations, Air Pollution Control District , County of Los Angeles , 1972 .

2 . DeCorso , S .M. , Hussey, C . E . , Ambrose , M. J . , "5ystem For Reducing Nitrogen-Oxygen Compound In The Exhaust Of A Gas Turbine" , United States Patent 3 , 826 , 080 , July 30 , 197� .

3 . Singh , P . P . , Young , W . E . , Ambrose , M . J . , "Formation and Control Of Oxides Of Nitrogen Emissions From Gas Turbine Systems" , 72-GT-22 , Amercian Society Of Mechanical Engineers .

4 . Ambrose , M . J . , Obidinski, E .S . , "Recent Field Test For Control Of Exhaust Emissions From A 35 MW Gas Turbine" , 72-JPG-GT-2 , American Society Of Mechanical Engineers .

5 . Carl , D . E . , Obidinski , E . S . , Jersey , C .A . , "Exhaust Emissions From A 25 MW Gas Turbine Firing Heavy And Light Distillate Fuels And Natural Gas" , 75-GT-68, American Society Of Mechanical Engineers .

6 . Carl , D . E . , Forsman , W . C . , Ambrose , M.J. , Obidinski, E . S . , "Log-Normal Distribution Of Particulate Measurements From A Gas Turbine Exhaust" , Gas Turbine Combustion and Fuels Technology, Winter Annual Meeting Of The American Society Of Mechanical Engineers , Atlanta , Georgia , November 27 - December 2 , 1977 , p p 27-30.

7 . Source Testing !1anual. Air Pollution Control District, County Of Los Angeles , 1972 .

8 . Source Testing Manual, South Coast Air Quality Management District , Los Angeles, 1977 .

9 . Carlson , G . , Unpublished Report, 1976 , Westinghouse Electric Corporation , Pittsburgh , Pa .

10 . Grosjean , D . , and Friedlander , S . K . , "GasParticle Distribution Factors For Organic And Other Pollutants In The Los Angeles Atmosphere" , Journal Of Ihe Air Pollution Control Association , Vol . 25 , No . 10 , Oc•t. 1975 , pp 1038 - 1044 .

11. Mueller , P . K . , Twiss , S . , Sanders , G . , "Selection Of Filter Media : An Annotated Outline" , 13th Conference On Methods In Air Pollution And Industrial Hygiene Studies , Berkeley, Calif. , Oct. 30-31 . 197'2 .

11


- ----- ---

12. Lee, R.E., Jr . , and Wagman, J . , "A Sampling Anomaly In The Determination Of Atmospheric Sulfate Concentration", American Industrial Hygiene Association Journal, May-June, 1966, pp 266-271.

13. Meserole, 5 . B . , Schwitzgebel, K . , Jones, B . F . , Thompson, C . M., Mesich, F . G . , "Sulfur Dioxide Interferences In The Measurement Of Ambient Particulate Sulfates", Research Project 262, Final Report, Vol. 1, Jan . 1976, Radian Corp., Austin, Texas, For Electric Power Research Institute, Palo Alto, Calif.

12


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