Comparative Results of Sampling Procedures Used During

Testing of Prototype Air Pollution Control Devices at New York City Municipal Incinerators

E. F. GILARDI and HOWARD F. SCHIFF

Roy F. Weston, Inc.

Wester Chester, Pennsylvania

INTRODUCTION

A challenging experience in gas sampling for air pol­lution control is under way in New York City. This sampling and analysis program is being conducted on three prototype air pollution control systems with a different system installed on a single furnace at three different multi-furnace incinerator plants. These instal­lations are:

1) 73rd Street Manhattan InCinerator; Chemico medium energy Venturi wet scrubber.

2) Southwest Brooklyn Incincerator; Wheelabrator (Lurgi) precipitator preceded by a down flow gas conditioning tower.

3) South Shore Brooklyn Incinerator; Research-Cottrell precipitator preceded by an up-flow gas conditioning tower.

The gas sampling and analysis program consists of de­termining the simultaneous particulate loading, preced­ing and following the prototype air pollution control systems. Another principal feature of this program is to sample simultaneously using the recommended tech­niques of both ASME anci the EPA Office of Air Pro­grams (OAP), the expectation being that perhaps a data correlation could be made between the two testing procedures. In addition to the usual sampling data, samples are being obtained for the determina-tion of the gaseous constituents such as organic acids, chlorides, hydrocarbons, oxides of nitrogen, and carbon monoxide. Carbon dioxide and oxygen are continuously analyzed and recorded during the sampling periods.

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Records of the usual operating parameters of the in­cinerator units are kept and integrated so that the emis­sion data can be correlated with the actual performance of the incinerator.

This test program was undertaken to provide guidance to the New York City Department of Public Works, De­partment of Sanitation, and Environmental Protection Agency in establishing the types of systems which should be incorporated in the remaining 24 furnaces in their seven incineration plants. The program will also provide some indication as to the nature and concentration of gaseous constituents of current interest in the stack ef­fluent. It is' hoped that the analysis of data generated will reveal a correlation between the (different) two samp­ling techniques which should be of interest to the regu­latory agencies and the operating agencies, as well as the designers, builders, and equipment suppliers for in­cineration facilities.

This paper principally discusses the significance of the gas sampling procedures and analysis with data of par­ticular interest resulting from the tests conducted at the 73rd Street Manhattan Incinerator equipped with a medium energy Venturi wet scrubber.

TEST PROGRAM

During February 1971 and in August 1971 tests were conducted at the 73rd Street Incinerator of the City of New York to establish emission levels of particulates and gaseous pollutants. These tests included simul­taneous sampling for gaseous constitutents. One gas sampling train (illustrated schematically in Fig. 1) is identified in this paper as an ASME type train incor-

S

T A

C

K

t

INCoNEL

PROBE

HOT BOX

THERMOCOU PLE

PI TOT TUBE

AND MUOIIETER

FLEX HOSE

C OARSE ALUMINUM

OXIOE (RA #9B)

THIMBLE

CONOENSER

200 GMS

SILICA GEL COUO WATER IN

Fig. 1 ASME particulate train scrubber outlet.

P 11 01 1 UB [ ANO MANOM[1[R

IMP INGERS IN ICE BATH

VALVE

THERM OCOU P L E

NOTE: ON THE SCRUBBER OUTLET. A VYCOR-GLASS, NICHROME

WIRE WRAPPEO PROBE WAS USEO

Fig. 2 EPA-CAP particulate train.

103

BLEED DAMPER FOR GAS VOLLNE CONTROL

BREEDti NG TO STACK

-

SAMP LE PORTS

D RYING G RATE

CHA RGI NG HOPPER

WATER QUENCH

FU RNACE

COMBUSTION 0 CHAMBER 0

o o

-... : (\ c::::J c::::J

RESIDUE CONVEYORS

SETTlI NG CHAMBER

TO RESIDUE QUENCH

WATER MAKE-UP

Fig. 3 Simplified section through Furnace No. 1 and scrubber.

porating standard 20-micron pass aluminum oxide thimble (RA Number 98). The other gas sampling train (illustrated schematically in Fig. 2) is identified in this paper as an EPA-OAP type train.

The 73rd Street Plant is one of three multi-furnace incinerator plants in New York City in which a full-scale prototype particulate stack emission control system had been installed on a single furnace to evaluate their per­formance [1]. Furnace No. 1 in this plant is equipped with a medium energy wet approach Venturi Scrubber.

The schematic arrangement of the furnace system in Fig. 3 indicates the location of the gas sampling stations. As usually found in so many older plants, the locations for suitable gas sampling stations had to be compromised. The only reasonably accessible location for gas sampling ahead of the scrubber was at the primary furnace outlet (Sample Ports "A"). This location required sampling from both sides of the furnace and at five levels. The furnace configuration at this location compounded by the usual wide fluctuations in gas velocity, flame pattern and high temperatures made sampling procedures very difficult and the data obtained virtually irreproducible.

Prior studies by the City had indicated that loca­tion for gas sampling after the scrubber and induced draft fan should be at the flue.gas duct elbow at the roof line (Sample Ports "B") (see Fig. 4).

The gas distribution pattern at the only physically practical sampling location, between the induced draft

fan outlet and the breeching elbow, left much to be de­sired. Fig. 5 shows velocities at sampling points ranging from zero to 50 ft/sec with most of the flow crowded to the outer side of the gas duct elbow. A total of 40 sampling points (five at each of eight ports) were used to obtain an average for these velocity variations. The revised Federal EPA criteria (December 23,1971 Fed­eral Register) would have increased the number of samp­ling points to 48 under such circumstances.

Even under these adverse conditions, only one samp­ling run out of 22 exceeded the allowance of ± 1 0 percent deviation from isokinetic sampling conditions. The average deviation from isokinetic conditions was less than 2 percent for these runs. All points were sampled for a minimum of 5 min.

RESULTS AND DISCUSSION

Fig. 6 shows the distribution of the calculated results of particulate sampling for representative runs. These 'results expressed in pounds per thousand pounds of dry flue gas show the relationship between the ASME type train and the EPA type train.

The higher catch of the OAP-EPA type train is evi­dent in this plot; however, there is no assurance that the higher catch of the OAP-EPA train represents physical particulate matter. Additional research into the source of material caught in the irnpinger train is presently being

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II'

SAMPLING PORTS 8"

0 () 0 0 ( ) () l) A 8 C D E F G

12 --S'

SHUT OFF DAMPER

t ,

12'

,

/ FAN MOTOR I

7 ' I I

� \ / FAN HOUSING " /

'- ./

Fig,4 Sample ports in exhaust breeching a�scrubber outlet,

105

PO I NT NUMB E R

�--------------- I 0' -6"'----------------11

POR T A POR T B PORT C PORT 0 PORT [ PORT F PORT G PORT H

� LESS THAN 10'/SEC � 20' /SEC TO lO'/SEC _ 40'/SEC TO SO /SEC

c=J IO"/SEC TO 20'/S.H � lO'/SEC TO 4 0'/ SEC

-

�

z

� z 0

::: � ,. !; �

�

�

� �

� 0

�

Fig,5 Particulate sampling locations at scrubber outlet position.

Sectional drawing (top view).

v V 0,1

0.6

0,5

0.4

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0,2

0.1

V V V

" , L ��'Y �;;--/9

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/ ./ V ...... ,1.\ �

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...... v V

V ......

10 20 lO 40 50 60 70 BO

PROBABILITY OF OCCURRENCE EOUIL TO OR LESS THIN GRIPH VIlUE

(I) TOTIL OF PROBE, CYCLONE, FILTER INO IMPINGER CITCH

(21 TOTIl OF PROBE INO TH IMBLE CATCH

V

90 95

Fig. 6 Normal Probability distribution of particulate emissions

at scrubber outlet.

106

L

9B

Gaseous Compound

Aldehyde Concentration, ppmv2

Flow Rate, Ib./hr.

Ammonia Concentration, ppmv Flow Rate, Ib./hr.

Chlorine Concentration, ppmv Flow Rate, Ib./hr.

Hydrogen Chloride Concentration, ppmv Flow Rate, Ib./hr.

Nitrogen Dioxide Concentration, ppmv Flow Rate, Ib./hr.

Nitric Oxide Concentration, ppmv Flow Rate, Ib./hr.

Organic Acids Concentration, ppmv Flow Rate, Ib./hr.

Sulfur Dioxide Concentration, ppmv Flow Rate, Ib./hr.

Hydrocarbons Concentration, ppmv Flow Rate, Ib./hr.

Carbon Monoxide Concentration, ppmv Flow Rate, Ib./hr.

1 Average of three tests. 2parts per milliun by volume. 3Less than 25 ppmv.

Average Value 1 at Scrubber Outlet

0.16 0.036

28.6 3.17

1.88 0.76

11.3 2.62

0.22 0.05

2.42 0.37

1.60 0.59

14.6 7.5

o o

Fig.7 Gaseous emissions - 73rd Street Incinerator.

conducted under an EPA sponsored research program. The OAP-EPA filter is specified as being 99.99 percent effective on 0.3 micron particles; therefore, the impinger catch more likely represents fume catch �ondensed in the impingers or reaction products of gaseous com­pounds in the flue gas.

The results of testing for gaseous emissions at the furnace outlet are considered at this time to be incon-

107

elusive. The addition of bleed air at the scrubber inlet, the difficulty in obtaining representative samples at the furnace outlet, the possibility of chemical reactions in the scrubber all contributed to our decision that report­ing of the scrubber inlet data for comparison with outlet data could be misinterpreted. Fig. 7, however, shows the emission data for gaseous compounds at the scrub­ber outlet. These values will be compared with similar data obtained from subsequent tests at the other proto­type installations.

The limited purpose of this presentation is to analyze the test results with respect to particulate sampling and analyses procedures. In this review each of the sampling elements are considered individually, i.e., probe catch, filter catch, impinger catch, etc. This enables a more direct comparison between sampling train elements, such as the filter of the EPA train and the thimble of the ASME train.

A concern about sampling downstream of the scrub­ber was the potential for moisture droplets disturbing the results by overloading the sampling train with dirty water. Determinations of moisture content from the impinger and silica gel catch were made and compared with temperatures recorded during the test period. Fig. 8 indicates the deviation of test points from the theoretical sat!lration moisture volume. Sixty-eight percent of the runs showed higher moisture concentra­tion than theoretical saturation. The points of maximum deviation from the theoretical curve reflect a variation from 35 percent less than theoretical moisture to 74 percent greater than theoretical.

The variation of these points from the saturation curve and their relatively uniform concentration at ap­proximately 28.4 percent moisture has been discussed at great length between members of our organization. Points representing simultaneous runs show an average temperature separation of 3 F and an average moisture percentage separation of 2.1 percent.

We believe that the presence of moisture in excess of saturation can be explained by considering water par­ticles swept from the demister assembly, water from the fan wash system as well as condensation due to tempera­ture loss (radiation) through the gas ducts.

The significance of the excess moisture becomes evi­dent when its effect on particulate concentrations is noted. Using saturation moisture instead of measured moisture for correction of dry gas conditions reduces the particulate concentration in the data reported by as much as 16 percent. The five points within the 136F to 142F temperature range average more than 10 percent lower in particulate concentration when moisture volume is based on saturation volume at the measured gas tempera­ture in lieu of measured volume.

38

34

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>-<D

� "" :::> 26 l-on

c:> ,.. I-

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• - OAP _ - ASIE

138 142 146 150 154 158

SATURATION TEMPERATURE

Fig. 8 Flue gas temperature vs. percent moisture.

50.000

45.000

"'-;; 40.000 1-

----i---,-F-_.--7f------'--t------t

35.000 I--;'----A'----�-+-----t------t

30.000 &.... __ "'---II...-___ ......:. ____ --L. ____ ..J JUDO J5 000 40 000

ASME

45 000 50.000

Fig.9 Relative measured dry gas flow, cfm dry flue gas.

108

.2

-3 ·3

_I

162 166

•

015 r-----.---------------.-------�---r--

e3

e p e1

010 �----.-------��_r� �------�----� 6

e 8

o 05 IL-_�

005 o 10 o 15 lSME

Fig. 10 Relative particulate catch, grains/scf @ 12% CO2,

A second item of concern was the correlation of cal­culated flue gas flows between simultaneous runs. The widely varying rates of gas flow at each sampling point combined with the wide variation in gas velocities across the gas duct indicated that similar gas volumes for the ASME and OAP trains might not be obtained. Fig. 9 shows the relationship actually obtained between simul­taneous runs. The majority of the points fall within 10 percent of being identical. The OAP train generally shows higher gas volumes and greater deviation from the equal value line. The variations are considered acceptable in light of the poor gas velocity pattern at the sampling location.

There is almost constant discussion in the engineer­ing community regarding the relationship between the dry filter catch in the ASME (thimble) and OAP (filter), and the material reported as catch in the series of wet impingers of the OAP train. The data made available by the sampling and analyses procedures used during these tests may provide some additional insight into these discussions.

Fig. 10 shows that the total catch (probe and filter plus impingers) reported by the OAP test train plotted against the (probe and thimble) catch reported by the ASME train. The great majority of points indicate the OAP catch exceeds the ASME catch by more than 20 percent. The points below the equal line are all as­sociated with a high probe catch in the ASME train.

o 15r-----,----------------r---------------

o 101------+-------------�------------__l

e 9

e1

e8 e 2

050�--��-------------4--------------_4

o 50 o 10 o 1 5

lSME

Fig. 11 Relative particulate catch, grains/scf @ 12% CO2, OAP

less impinger catch.

Eliminating the impinger catch from the results of the OAP train as illustrated in Fig. 11 brings the points falling above the equal catch line much closer together and closer to the line. The average catch in the OAP impingers represented approximately 20 perent of the total catch in the OAP train. However, the higher efficiency of the OAP filter over the ASME thimble re­sults in the average OAP probe and filter catch remaining approximately 7 percent greater than the ASME probe and thimble catch. This low average was strongly influ­enced by the high probe catch in three of the ASME samples. The majority of the points indicate that the OAP probe and filter catch will average from 10 to 20 percent greater than the ASME probe and thimble catch.

The relationship between impinger catch and the catch in the front of the test train (probe plus filter or thimble) is shown in Fig. 12. Although not reported in previous data, all condensate from the back end of the ASME train was processed for solids content. Also an ether-chloroform extraction was made on Runs 8, 9 and 10 of the ASME condensate impinger catch.

Fig. 12 shows that the organic extract was generally an insignificant portion of the impinger catch. Therefore, the impinger catch probably represents either fume material passing the filter or the products of chemical reactions in the impinger train or perhaps a combination of both. The new EPA criteria and procedures published in the Federal Register of December 23, 1971, no longer

109

P 2 3 4 5 6 8 9 _1_0_

0.10

0.08 0: UJ l-

I- 0.06 0 0

0 :z:

u ex: IX> UJ 0 04 :::> IX> u 0

0: 0 0-0: 0 02 ex: 0 :z: ex: l-V> 0 00 0: UJ 0-V> 0.02 :z: c( 0: t!>

0: 0.04 � UJ c( t!> :::> :z: I-u 0-c( :IE 0.06

0. 08

o. 10 N OTES. THE F IRST BAR F OR EACH RUN REPRESE N TS OAP TEST OATA THE SECOND BAR FOR EACH RUN REPRESENTS ASME TEST DATA THE SHADED PORTION ABDVE THE NEUT RAL L INE REPRESE NTS PROBE CATCH THE-SHADED PORT ION BELOW THE NEUTRA L LINE REPRESENTS ORGA N IC EXTRACT

Fig. 12 Comparative values of dry and wet catch.

requires that this impinger portion of the catch be reported.

The high levels of deposition within the probe indicate that extreme care must be exercised in handling and cleaning the probe to ensure complete determination and reporting of all of the particulate captured. Also, because of the potential of developing reaction products, extreme caution must be exercised to prevent condensa­tion of moisture in the probe and filter (thimble) .

The data as presented in this paper are not sufficient to permit finer conclusions to be reached. However, the care exercised in performing these tests and the relatively large number of simultaneous runs using the OAP and

110

ASME trains provides additional useful information which may soon permit accurate evaluation of test pro­cedures and equipment performance.

The cooperation of officials of the City of New York, plant personnel and our laboratory personnel in obtaining and analyzing this data is deeply appreciated.

REFERENCES

III W. Ellison, "Control of Air and Waler Pollution from

Municipal Incinerators with the Wet Approach Venturi Scrubber,"

Proceedings of 1970 National Incinerator Conference, ASME,

New York, N. Y., 1970, pp. 157-166.