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# OAR Box 1313
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### Document

Number: 

# 37 ) ll-B-1 1

Docket Number: 

# A-88-0 2

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# FINA L P. 2 

## A-88-0 2 MIDWES T RESEARC H INSTITUT E

450 5 Creedmoo r Roa

d Raleigh , N.C

. 2761 2 Telephon e (919

) 781-575 0

p " •\v, \\

\ •'" •\ 8 1 \ \ 8U - : ' .•

•



### Date : Jul y

29 , 198 6 ,' ' \ J\ H * 8 

### ^ l " (Finalize dAugus t 28 , 1986 ) ] •

* Subject : Sit e Visit—Piedmon t Industria l Platin g

Chromiu m Electroplatin g NESHA P EPA Contrac t 68-02-3817 ; ESE D Projec t 85/02 a MR I Projec t 7717- K From : Randy

Strai t /Ll To : Al Vervaer t

ESED/ISB/SS S (MD-13 ) U . S . Environmenta l Protectio nAgenc y Researc hTriangl e Park , N.C . 2771 1 I . Purpos e Th e purpos e o f thi s sit e visi t wa s t o gathe r backgroun dinformatio n abou t th e chromiu

m electroplatin g operatio na t thi s plan t an dt o determin e th e suitabilit y

o f thi s plan t fo r chromiu m emission s testin g t o asses s th e effec t o f scrubbe r wate r recirculatio no nscrubbe r performance . II . Plac e an

dDat e Piedmon t Industria l Platin g Pos t Offic e Box581 3 20 0 Monro e Stree t Statesville , Nort hCarolin a 2867 7 (704 ) 872-276 6 Ma y 29 , 198 6 III . Attendee s Piedmon t Industria l Platin g Bo bMiller , Plan t Manage r U . S . Environmenta l Protectio nAgenc y Al Vervaert , IS B Midwes t Researc hInstitut e Randy Strai t

/P. 3

IV . Discussio n
W e arrive d a t th e plan t a t 1:0 0 p.m . Th e visi t consiste do f a tou r o f th e plan t an

d a discussio nabou t th e hardchromiu m electroplatin g operatio nan

d chromiu

m emission s captur e an dcontro l equipment . A . Genera l Piedmon t Industria l Platin g i s a jobsho p tha t perform s har d chromiu m electroplatin g o f textil e machiner y part s an

dindustria l roll s an dtubing . B . Proces s Informatio n Ther e ar e thre e har d chromiu m platin g tank s use da t thi s plant , whic har e arrange d a s show ni nFigur e 1 . Th e dimension s an doperatin g parameter s fo r eac htan k ar e liste d i nTabl e 1 . Th e lon g tan k i s use dt o plat e long industria l roll s an dtubin g a s wel l a s smalle r parts . Th e tan k i s equippe dwit hon e 6,000 - an dthre e 1,000-amper e rectifiers . Whe nplatin g industria l roll s o r tubing , th e 6,000-amper e rectifie r i s used . Whe nplatin g smalle r an ddifferen t kind s o f parts , upt o fou r wor k station s ca nb e se t upi nth e tank . Thre e o f th e wor k station s ar e charge dwit hth e 1,000-amper e rectifiers , an don e wor k statio ni s charge dwit hth e 6,000-amper e rectifier . Th e 10-foo t tank contain s u pt o fiv e wor k stations , an d eac hwor k statio ni s charge dwit ha separat e 1,000-amper e rectifier . Th e dee p tank currentl y i s no t bein g used . Th e plan t i s i nth e proces s o f installin g a fourt hhar dchromium platin g tank . Th e tan k i s 1 4 fee t (ft ) i nlength , 4. 5 f t i nwidth , an d 5 f t i ndept han

d wil l contai nabou t 2,35 0 gallon s (gal ) o f platin g solution . Porou s pot s ar e use d a t thi s plan t primaril y t o reduc e trivalen t chromiu m contaminatio no f th e platin g baths . Th e concentratio no f trivalen t chromiu

m ion s increase s t o level s tha t contaminat e th e platin g bath s whe nth e surfac e are a o f th e cathode s plate di s substantiall y large r tha nth e surfac e are a o f th e anodes . Th e pot s ar e mad e o f cerami c tha t contain s pore s rangin g fro m 0. 5 t o 1. 0 micrometer s indiameter . Th e pot s ar e place di na platin g bat ht o oxidiz e trivalen t chromiu m t o hexavalen t chromiu m whil e platin g i s performed . Severa l anode s ar e place daroun dth e outsid e o f eac hpot , an d a cathod e i s place dinsid e eac hpot . Th e anode s an dcathod e ar e bot hforme d fro m anallo y

consistin g o f 94-percen t lead an d6-percen t antimony . Abou t 9 volt s an d30 0 ampere s o f direc t curren t ar e applie d t o th e anode s surroundin g eac hpot . Trivalen t chromiu m ion s presen t i nth e bat hmigrat e t o th e anode s wher e the y reac t wit hoxyge nt o for m chromi c aci d(Cr0 3 ) . Th e porou s pot s provid e a selectiv e membran e tha t prevent s th e hexavalen t chromiu m anion s i nth e bat hfro m flowin g t o th e cathod e wher e the y woul d b e reduce d an d deposited . A

secondar y functio no f th e pot s i s t o remov e meta l contaminant s fro m th e platin g



### <5LSTAC K

DUAL L SINGL E PACKED-BE D SCRUBBE R

WAL L LEGEN D AIRFLO W

WAL L

LONGTANK " ^

CAPTUR E HOOD S 10-FOO T TAN K 

# - A CAPTUR E HOOD S

( * Figur e 1 . Schemati c o f Piedmon t Industria l Platin g hardchromiu

m platin g operation .

J*

.TABL E 1 . DIMENSION S AND OPERATINGPARAMETER S O F HAR D CHROMIU M PLATINGTANK S A T PIEDMON T INDUSTRIAL PLATING

Tank identifi catio n Dimension s

(1 , w , d) , ft. a Capacity , ga l Hour s of .

operatio n Voltage ,

volts 0 Current ,

ampere s , e Metho do f

coolin g Constituents ,

_oz/_gal_

r CrO : H ? S0 ,

Lon g tank 10-foo t tank
Dee ptank 23 , 3 , 4

10 , 3 , 4

3 , 4 , 1 0 2,06 4

89 8

89 8 8 , 5 , 5 0

8 , 5 , 5 0 1 2

1 2

1 2 9,00 0 5,00 0 Wate r

Wate r 3 2

3 2 0.3 2

0.3 2

4,00 0 Wate r

* 1 = length , w = width , d = depth . D hours/day , days/week , weeks/year . ^Tan k no t currentl y

i nuse . Maximu m operatin g values . e A tota l o f fou r wor k station s ca nb e used i nth e lon g tank : thre e o f th e wor k station s ar e charge d wit ha 6,00 0 amper e wor k station . A tota l o f fiv e wor k station s ar e use di nth e 10-foo t tank : eac h wor k statio ni s charge d wit hseparat e 1,00 0 amper e rectifiers . Cr0 3 = chromi c acid , H 2 S0 4 = sulfuri c acid .



## >4 > T lP. 6

solution . Som e meta l contaminant s containe di nth e platin g solutio nar e transforme d t o cation s an d flow throug hth e pot s t o th e cathod e wher e the y deposi t eithe r o nth e cathod e o r o nth e insid e o f th e pot s formin g a n olive-dra bgree nsludge . Th e pot s ar e remove dfro m th e tank an

dcleane d ever y 2 4 t o 3 2 hour s becaus e accumulatio no f sludg e i nth e pot s increase s resistanc e an

ddecrease s th e amoun t o f curren t require dt o oxidiz e trivalen t chromiu

m t o hexavalen t chromiu m efficiently . C . Emission s Contro l Th e long tank an

d10-foo t tank ar e equippe dwit hdouble-side ddraf t hoods , an

dth e dee ptank i s equippe dwit ha single-side ddraf t hood . Th e hood s wer e manufacture dan dinstalle db

y Keslma c Metal s Company locate di n Greensboro , Nort hCarolina . Emission s fro

m al l thre e tank s ar e ducte d togethe r an dvente dt o a singl e packed-be d horizontal-flo w scrubbe r manufacture db y Dual l Industries , Inc . Th e scrubbe r wa s purchase da s use dequipmen t an dwa s installe d a t th e plan t approximatel y 2 year s ago . Th e ga s flow rat e o f th e scrubbe r i s 11,50 0 actua l cubi c fee t pe r minut e (acfm) , an dth e wate r flow rat e i s 34. 5 gallon s pe r minute . Th e scrubbe r wate r drain s int o a sum pi nth e botto

m o f th e scrubbe r an

d i s recirculate db

y a 1.5-horsepowe r pum pan d spraye dcountercurren t t o th e ga s flow i nfron t o f th e packe d bed . A senso r i s use d t o monito r th e wate r leve l i nth e sum pwhic h contain s abou t 10 0 ga l o f water . Approximatel y 2 5 ga l o f clea nwate r ar e automatically

adde d ove r th e packe d be dwhe nth e senso r call s fo r mor e wate r t o mak e upfo r evaporatio nlosses , whic hoccur s abou t fou r time s pe r day . Clea nwate r i s use d t o was hdow nth e scrubbe r onc e pe r day , an dth e scrubbe r wate r i s the ndraine dint o th e platin g tanks . Th e chromi c aci d concentratio no f th e scrubbe r wate r i s estimate dt o rang e fro m 1 t o 2 ounce s pe r gallo no f water . Th e scrubbe r i s equippe dwit ha chevron blad e mis t eliminato r tha t i s installe d behindth e packe dbe dt o contro l wate r an

d chromic-aci d droplet s tha t ma y brea k throug hth e packe dbed . Th e mis t eliminato r i s no t washe d dow nbu t i s inspecte dfrequently . I f droplet s appea r inth e mis t eliminator , th e packe dbedi s reconditione dt o preven t th e breakthroug ho f droplets . Th e scrubbe r i s locate d outsid e o f th e plant . Ther e ar e 3 f t o f straigh t ductwor k betwee nth e outsid e wal l o f th e buildin g an danelbo w tha t connect s t o th e inle t o f th e scrubber . Th e stac k contain s abou t 6 f t o f straigh t ductwork . Th e outsid e diamete r o f th e ductwor k i s 2 4 inche s a t bot hth e inle t an

doutle t o f th e scrubber . Th e plan t plan s t o instal l a fan/separato r scrubbe r manufacture db y Tri-Mer ® Corporatio nt o contro l chromiu m emission s fro

m th e fourt htan k tha t i s bein g installed . Th e uni t wa s purchase da s use dequipment . Th e ga s flo w rat e o f the scrubbe r shoul dbe abou t 8,00 0 acfm . Th e ductwor k a t th e inle t o f th e scrubbe r wil l be a straigh t sectio nrangin g fro m 6 t o 9 ft.i nlengt han

d 2 4 t o 2 8 inche s i noutsid e diameter .



### T TP. 7

D . Conclusion s Th e plan t appear s t o b e a nexcellen t candidat e fo r conductin g emission s test s t o determin e th e effec t o f scrubbe r wate r recirculatio no n scrubbe r performanc e fo r th e followin g reasons : (1 ) Th e thre e chromiu m platin g tank s a t thi s facilit y appea r t o hav e effectiv e emissio ncaptur e systems , (2 ) th e Dual l singl e packed-be d scrubbe r use dt o contro l chromiu m emission s a t th e plan t i s representativ e o f th e type s o f scrubber s commonl y applie d t o contro l chromiu m emission s fro

m hardchromiu

m platin g operations , (3 ) chromi c aci daddition s t o th e scrubbin g wate r ca nb e easil y made , (4 ) ther e i s adequat e length s o f straigh t duc t a t bot hth e inle t an doutle t o f th e scrubbe r fo r testing , an d(5 ) Mr . Mille r i s ver y cooperativ e an

dha s volunteere dt o assis t u s i nth e performanc e o f th e tests . Becaus e th e scrubbe r wa s installe da s use dequipment , Dual l Industrie s shoul d b e contacte dan d aske dt o inspec t th e uni t befor e a fina l decisio ni s mad e t o tes t th e scrubbe r t o ensur e tha t i t i s operatin g normally , size dcorrectly , an d representativ e o f th e singl e packed-be d scrubbe r currentl y

manufacture db

y Duall .



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