•

£ J ^ 

OAR Box 1313 

Prepped by LaTeia Shed 

Document Number: 

48) ll-B-22 

Docket Number: 

A-88-02 

Printed 6/12/2008 9:03:29 AM Sheet 48 of 99 
® 

PJL 

A-88-02 

MIDWEST RESEARCH INSTITUTE 

4505 Creedmoor Road 

Raleigh, N.C. 27612 

Telephone (919) 781-5750 

i-. ' . '; "• '7 

Date: March 16, 1987 

(Finalized April 2, 1987) 

Subject: Site V1 sit—Pratt and Whitney 

Chromium Electroplating NESHAP 

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

MRI Project 7717-K 

From: 

To: 

Robin Barker $Y 

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 chromic acid anodizing operations at this plant and to assess 

visually the amount of misting from the two chromic acid anodizing 

tanks. 

II. Place and Date 

Pratt and Whitney 

400 Main Street 

East Hartford, Connecticut 06108 

(203) 565-2016 

December 17, 1986 

III. Attendees 

Pratt and Whitney * 

John L. Russell, Plant Engineer 

U. S. Environmental Protection Aqency (EPA) 

Al Vervaert, ISB 

Midwest Research Institute 

Robin Barker 

/ 
P.3 

IV. Discussion 

We arrived at the plant at 1:30 p.m. During the visit, there was a 

discussion about the chromic acid anodizing operations followed by a tour 

of the facility. 

A. General 

Pratt and Whitney is a captive shop that performs chromic ad d 

anodizing of aircraft parts such as gearboxes. The facility employs 

11,000 people and operates 24 hours per day, 6 days per week. The 

operation of the anodizing process 1s variable, depending upon the amount 

of work requiring anodizing. 

B. Process Descriptions 

There are two Identical anodizing tanks at this facility. Each tank 

1s 2.1 meters (m) (7 feet [ft]) long, 2.1 m (7 ft) wide, 2.1 m (7 ft) deep 

and holds 10,145 liters (2,680 gallons) of anodizing solution. The 

anodizing solution contains chromic acid in a concentration of 

approximately 120 grams per liter (g/a) (16 ounces per gallon [oz/gal]) of 

water. The operating temperature 1s 60°C (140°F). 

The tanks are equipped with manual rectifiers that are used to step 

the voltage to 20 or 40 volts over a 30-m1nute period. (The voltage used 

depends upon the type of part being anodized.) The voltage 1s then 

maintained at 20 or 40 volts for the remainder of the anodizing time. The 

anodizing time typically ranges from 40 to 90 minutes. The current 

applied during the anodizing time ranges from 200 to 400 amperes. 

The facility has five other tanks that contain chromic add. These 

tanks are used to strip the aluminum substrate and to seal the aluminum 

after anodizing. The chromic acid concentration of the solution in these 

tanks ranges from 7.5 to 120 g/a (1 to 16 oz/gal) of water. 

C. Emission Control 

Both anodizing tanks are equipped with single-sided lateral hoods to 

capture any chromic acid mist that may be generated during anodizing. 

There are no control devices in place to treat the ventilation exhaust 

gases. 

V. Observations 

Pratt and Whitney is representative of other captive anodizing 

shops. At the time of the visit, the anodizing tanks were not 1n 

operation so no visual assessment of the amount of misting could be made. 

SZ-