SKlafka-CoreMaking,22may02

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Wingra Engineering, S.C. 1

Influence of EmissionEstimates on BACT for IronFoundry Core Making

Steven Klafka, PE, DEE

Wingra Engineering, S.C.A&WMA Conference 2002


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Iron Foundry Case Study Existing iron foundry in Indiana.

Addition of two coldbox core making machineswith combined capacity of 6 tons per hour.

Project required Prevention of SignificantDeterioration (PSD) air quality permit.

Permit requirements included determination ofBest Available Control Technology (BACT).

PSD applicability based on plant-wide VOCemissions increase from debottlenecking.


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Core Making Process Cores form internal space in castings.

Molten iron poured into molds flowsaround core to form internal voids.

Cores - mixture of sand & organic resin.

Resin type is phenolic-urethane. Catalyst used to activate resin.


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Core Making ProcessContd

Mixing

Organic binder mixed with silica sand.

Core Forming Sand/resin mixture blown into the mold box.

Catalyst injected to cure resin.

Catalyst purged from core machine.

Storage

Core removed for finishing, storage, delivery.


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Core Making Flow Diagram

Mixing CoreMachines

CoreStorage

Baghouse Scrubber

VOCPM, VOC

VOC


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VOC Emissions from Catalyst VOC generated by catalyst and resin

Catalyst Emissions

Triethyl Amine or TEA

Typical usage: 2-7 lbs/ton of core

Proposed usage: 3 lbs/ton of core

Assume 100% of catalyst emittedfrom core machines.


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VOC Emissions from Resin Resin Emissions

Evaporation of VOC constituentsfrom mixing, core machine & storage

Function of resin usage & VOC content

Little attention to resin losses in priorBACT analyses or permits.

Loss Range = 0.1 - 1.0 lbs/ton of core



Resin VOC Emission Methods American Foundrymans Society

(AFS) Form R booklet. Ohio Cast Metals Association

(OCMA) study in 1998.

Resin manufacturers evaporation tests Core making stack tests



AFS Form R Booklet Produced by AFS and the Casting

Industry Suppliers Association. Assist foundries with Form R TRI.

Provides estimates for reportable

chemicals in core and mold binder. Estimates fraction of resin remaining in

core and fraction released.



Resin Loss Using AFS Form R

ConstituentContent

(%)AFS Loss

(%)Resin Loss

(%)

Formaldehyde 0.11 2.00 0.002Naphthalene 4.92 3.25 0.160

Trimethylbenzene 1.62 3.25 0.053

Total 0.215

Total Resin Loss = 0.215%



1998 OCMA Study Laboratory resin evaporation tests.

Measured weight loss during mixing,forming, and storage.

No catalyst used during test.

Based on 1% resin in core sand.



Resin Loss using OCMA StudyStep

Time(hours)

Resin Loss(%)

Resin Loss(% of Total)

Mixing 0.03 0.39 12Machine 0.5 0.55 17

Storage 3 0.77 24

Storage >3 1.55 47

Total 12 3.26 100

Total Resin Loss = 3.26%



Resin Manufacturer Tests

Based on OCMA methodology.

Various resins evaluated tocompare evaporative losses.

Resin alternatives suitable for

Indiana project.


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Resin Loss from Manufacturers

ResinTime Elapsed

(hours)

Resin Loss

(%)A 3 3.0

B 3 1.2

Total Resin Loss = 1.2 to 3.0%


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Core Making Stack Tests

Conducted on existing operations

Tests for mixing and core machine Testing of core storage area not

practical due to open area.

Total VOC measured by Method 25 TEA measured by Method 25A


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Resin Loss using Stack Tests Mixing

Method 25A: 0.54 lbs VOC/hr, 0.40% of resin

Method 25: 0.61 lbs VOC/hr, 0.45% of resin Core Machine

Method 25A: 14.0 lbs VOC/hr

Method 25: 16.5 lbs VOC/hr

Method 25: 17.6 lbs TEA/hr, 3.4 lbs VOC/ton

TEA emissions > Total VOC

Resin loss measurements not possible.


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Resin Loss ComparisonMethod AFS OCMA Mfg A Mfg B Test

Resin Loss(%)

0.215 3.26 3.0 1.2 0.45

VOC @1%

(lbs/ton)0.043 0.65 0.60 0.24 0.09

VOC @1.5%

(lbs/ton)0.06 0.98 0.90 0.36 0.14


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Final Mixing Loss Estimate Mixing Loss

Test used Resin A; project to use Resin B Combined stack test and mfg lab tests

Resin B Loss = 0.45% Resin A Loss

x (1.2/3.0) = 0.18% Resin B Loss = 0.14 lbs/ton Resin A Loss

x (1.2/3.0) = 0.05 lbs/ton


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Core Machine Loss Estimate

Core Machine Loss

Combined stack test and mfg lab tests Mfg Total Resin B Loss Mixing Loss

0.36 0.05= 0.31 lbs/ton

Storage Loss Losses included with core machine.


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BACT Control Options Mixing

Regenerative Thermal Oxidizer

Carbon Adsorption

Core Machine

Packed Bed Scrubber

Regenerative Thermal Oxidizer

Carbon Adsorption


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Mixing BACT Analysis

Control Alternative UncontrolledVOC(lbs per hour)

Cost Effectiveness($ per ton)

RTO 0.30 609,810

Carbon Adsorption 0.30 161,920


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BACT for Mixing

High cost effectiveness due to relatively

low VOC emissions. IDEM feasibility threshold of $8,000

per ton of VOC removed.

No add-on controls required.


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Core Machine BACT Analysis

Control

Alternative

UncontrolledVOC

(lbs per hour)

ControlledVOC

(lbs per hr)

CostEffectiveness($ per ton)

CarbonAdsorption

19.86 0.40 14,520

RTO 19.86 0.40 9,041

Scrubber 19.86 2.22 2,835


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BACT for Core Machine RTO and carbon adsorption exceed IDEM

threshold for economic infeasibility.

RTO exceeds cost effectiveness used forprior Wheland BACT of $4,928/ton.

Packed bed scrubber considered BACT.


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RTO Cost Effectiveness Versus Resin Loss

BA

02000

4000

6000

8000

1000012000

14000

0 1 2 3

Resin Loss Emission Factor

(lbs per ton of core)

Co

stEffectiveness

($perton

VOC

)

2 lbs TEA/ton 3 lbs TEA/ton

4 lbs TEA/ton 5 lbs TEA/ton

BA


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Effect of VOC Loss on RTO Cost

Cost effectiveness varies with catalyst usageand resin losses.

Typically values can result in RTO as BACT.

If case study foundry had used Resin A --

Core machine resin loss increases from 0.36 to

0.90 lbs/ton. Cost effectiveness decreases to $7,676/ton.

RTO becomes economically feasible and BACT.


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Wingra Engineering S C 27

Conclusions Use of RTO on core making operations

will receive serious consideration for

future BACT evaluations. Cost effectiveness and feasibility of

control options are dependent oncatalyst usage and resin losses.

Resin losses, though small, effect theoutcome of the BACT analysis.

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