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OAR Box 1814 

Prepped hy Ollie Stewart 

Document Number: 

40) ll-B-18 

Docket Number: 

A-88-02 

Printed 11/7/2008 7:22:08 AM Sheet 40 of 63 
$ ) 

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-IB 

A-88-02 

MIDWEST RESEARCH INSTITUTE 

4505 Creedmoor •• 

Raleigh N C 

Date: March 12, 1987 

(Finalized April 21, 1987) 

Subject: Site Visit—Diamond Chrome Plating, Inc. 

Chromium Electroplating NESHAP 

EPA Contract 68-02-3817; ESED Project 85/02a 

MRI Project 7717-K 

From: Randy Strait i^. 

To: Al Vervaert 

ESED/ISB/SSS (MD-13) 

U. S. Environmental Protection Agency 

Research Triangle Park, N.C. 27711 

I. Purpose 

The purpose of this site visit was to gather background information 

about the hard chromium electroplating operation at this plant and to 

determine the suitability of a Tr1-Mer® fan/separator scrubber for 

chromium emissions testing. 

II. Place and Date 

Diamond Chrome Plating, Inc. 

604 South Michigan Avenue 

Post Office Box 312 

Howell, Michigan 48843 

(517) 546-0150 

May 22, 1986 

III. Attendees 

Diamond Chrome Plating, Inc. 

Jack C. Beatty, III, General Manager 

Midwest Research Institute 

Randy Strait 

/ 
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IV. Discussion 

The visit consisted of a discussion about the hard chromium 

electroplating operations and chromium emission capture and control 

equipment at the plant. The discussion was followed by a complete tour of 

the plant. 

A. General 

Diamond Chrome Plating, Inc., 1s a large-size job shop 

(35,000 square feet) that performs hard chromium plating of aircraft, 

machine tool, and hydraulic parts. The plant has been 1n operation for 

32 years. The plant is operated 18 hours per day, 5 to 6 days per week, 

and 50 weeks per year and uses from 60,000 to 80,000 pounds of chromic 

a d d per year. 

B. Process Description 

Twelve hard chromium plating tanks at this facility are vented to a 

Tr1-Mer® fan/separator scrubber. The tanks are numbered 1 through 8 and 9 

through 13. The dimensions and operating parameters of the 12 tanks are 

presented 1n Table 1. The concentration of chromic ad d 1n the plating 

baths ranges from 28 to 33 ounces per gallon (oz/gal) of plating 

solution. Sulfuric ad d 1s used as a catalyst 1n the plating baths 1n a 

concentration ranging from 0.28 to 0.33 oz/gal of plating solution. The 

baths are operated at about 132°F and are cooled with water. The plant 

also operates several other hard chromium plating tanks that are vented to 

two Cellcote vertical-flow packed-bed scrubbers. 

C. Emissions Control 

Each of the 12 tanks 1s equipped with a double-sided draft hood 

vented to the one Tr1-Mer® fan/separator scrubber that was purchased as 

used equipment and Installed at the plant 1n 1983. The scrubber was 

originally installed at a plant 1n Chicago, Illinois, 1n 1974. The gas 

flow rate to the scrubber is 45,000 cubic feet per minute, and the unit 1s 

equipped with a 75-horsepower motor. 

A diagram of the fan/separator scrubber with a single packed bed 1s 

shown 1n Figure 1. The scrubber at this plant contains two packed beds. 

The fan/separator scrubber consists of two stages: a dynamic scrubbing 

stage followed by an impingement stage. In the first stage, ventilation 

air 1s ducted Into the eye of a backward-blade centrifugal fan where 1t 1s 

sprayed with high-pressure, low-volume water or scrubbing liquid. The 

water flow rate to the eye of the fan 1s 24 gallons per minute (gal/m1n) 

at 10 pounds per square Inch (ps1) of pressure. Contaminant aerosols are 

entrained and spun out centrifugally onto the fan scroll. The centrifugal 

action created by the fan wheel eliminates approximately 50 percent of the 

Incoming chromic acid mist. In the second stage, the exhaust gas flows 

Into an expansion chamber containing two packed beds of hydrophobic tubing 

made of polypropylene. The expansion chamber 1s designed to reduce the 

velocity of the contaminated gas stream to no more than 500 feet per 

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TABLE 1. DIMENSIONS AND OPERATING PARAMETERS FOR TWELVE 

HARD CHROMIUM PLATING TANKS 

Tank No. 

1 

2 

3 

4 

5 

6 

8 

9 

10 

11 

12 

13 

Dimensions 

(1, w, d), fta 

10, 3, 4 

16, 3, 4 

3, 3, 6 

10, 3, 4 

4, 4, 10 

24, 2.5, 4 

10, 3, 4 

10, 3, 4 

10, 3, 2.5 

34, 2.5, 4 

10, 3, 2.5 

10, 3, 3 

Capacity, 

gal 

890 

1,430 

400 

890 

1,190 

1,790 

890 

890 

560 

2,540 

560 

670 

Voltage, 

volts0 

12 

12 

12 

12 

12 

12 

12 

12 

12 

12 

12 

12 

Currentamperes 

8,800 

12,500 

3,500 

7,500 

6,000 

10,000 

6,500 

5,000 

5,000 

17,000 

9,000 

3,400 

!*1 = length, w = width, d = depth. 

DMax1mum values for each tank. Actual voltage 

to 12 volts. Actual current values can range 

the maximum current values. 

values can range from 3.5 

from 10 to 100 percent of 
CUM. nr in 

nunc MIMS 

CMIMIIMl IUM II MMHI 

III! Ul MIIICUS 

IICI riissw. (•• IIIIMI m u 

niaar U-III I siPiiiim 

( u m PMIICUS ) 

SICIIIlll St Mill III .1 

muraiut uu MM HKIM r « CMIOUMS 

HH IHMI 

IIIIIMt SIMI-IIU I? MIIICU 

••MCIIM I IIIIKiPIlM 

It* MfCIIM-1 Ml CMISI 

I I PliCHM UlClllt 

CMI/UII»lfl Mil l I I Ullll _«SI! 

iiuiam 11 mass nisi 

^ Figure 1. Fan/separator scrubber. 
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minute for maximum Impingement efficiency. The gases are sprayed with 

water before the first packed bed. Because the gas flow changes direction 

numerous times as 1t passes through the packed beds, chromic acid droplets 

Impinge on the packing media and separate from the air stream. The water 

flow rate to the packed-bed stage 1s 48 gal/m1n at 10 psi. Contaminated 

water 1s pumped from the unit to a remote recirculation tank and then 

recirculated through the scrubber to reduce water consumption costs. The 

scrubber water 1s drained once per week and 1s reused 1n the plating 

tanks. 

The plant has modified the scrubber by Installing four spray nozzles 

between the first and second packed beds because chromium droplets were 

occasionally breaking through the second packed bed. The water for these 

nozzles 1s clean makeup water that typically 1s used to offset evaporation 

1n the scrubber and that otherwise would be dumped Into the sump. Water 

flow 1s 3.2 gal/min total to the four nozzles Intermittently as needed to 

maintain the water level. The nozzles operate from 10 to 30 minutes each 

hour depending on weather conditions. Mr. Beatty stated that Installing 

these fresh water spray nozzles eliminated the breakthrough problem. 

V. Conclusions 

Diamond Chrome Plating, Inc. 1s representative of a large-size job 

shop that performs hard chromium plating of aircraft, machine tool, and 

hydraulic parts. Emission testing of the fan/separator scrubber 1s not 

recommended because there are only about 2 feet of straight ductwork at 

the Inlet of the unit, which would not allow for the proper location of a 

test port. Also, because the scrubber 1s not equipped with a stack, a 

stack would have to be Installed to perform outlet emission testing. 

Exhaust gases are vented through a 50-1nch-square opening located above 

the second packed bed. Mr. Beatty was very cooperative during the visit, 

and the information provided will be most useful to the chromium study.