Wingra Engineering, S.C.1 Influence of Emission Estimates on BACT for Iron Foundry Core Making...

Wingra Engineering, S.C. 1

Influence of Emission Estimates on BACT for Iron Foundry Core Making

Steven Klafka, PE, DEEWingra Engineering, S.C.A&WMA Conference 2002

Wingra Engineering, S.C. 2

Iron Foundry Case Study

Existing iron foundry in Indiana. Addition of two coldbox core making

machines with combined capacity of 6 tons per hour.

Project required Prevention of Significant Deterioration (PSD) air quality permit.

Permit requirements included determination of Best Available Control Technology (BACT).

PSD applicability based on plant-wide VOC emissions increase from “debottlenecking”.

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Core Making Process

Cores form internal space in castings. Molten iron poured into molds flows

around 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 Process Cont’d

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 emitted from core machines.

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VOC Emissions from Resin

Resin Emissions Evaporation of VOC constituents from mixing, core machine & storage Function of resin usage & VOC

content Little attention to resin losses in prior

BACT analyses or permits. Loss Range = 0.1 - 1.0 lbs/ton of core

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Resin VOC Emission Methods

American Foundryman’s Society (AFS) “Form R” booklet. Ohio Cast Metals Association (OCMA) study in 1998. Resin manufacturers evaporation

tests Core making stack tests

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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.

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Resin Loss Using AFS Form R

Constituent Content

(%) AFS Loss

(%) Resin Loss

(%) Formaldehyde 0.11 2.00 0.002 Naphthalene 4.92 3.25 0.160

Trimethylbenzene 1.62 3.25 0.053 Total 0.215

Total Resin Loss = 0.215%

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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.

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Resin Loss using OCMA Study

Step Time

(hours) Resin Loss

(%) Resin Loss

(% of Total) Mixing 0.03 0.39 12 Machine 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%

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Resin Manufacturer Tests

Based on OCMA methodology. Various resins evaluated to

compare evaporative losses. Resin alternatives suitable for

Indiana project.

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Resin Loss from Manufacturers

Resin Time 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 Comparison

Method AFS OCMAMfg 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 Uncontrolled

VOC (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

Uncontrolled VOC

(lbs per hour)

Controlled VOC

(lbs per hr)

Cost Effectiveness ($ per ton)

Carbon Adsorption

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 for prior Wheland BACT of $4,928/ton.

Packed bed scrubber considered BACT.

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RTO Cost Effectiveness Versus Resin Loss

BA

0

20004000

6000

8000

1000012000

14000

0 1 2 3

Resin Loss Emission Factor(lbs per ton of core)

Cost

Eff

ect

iveness

($ p

er

ton V

OC)

2 lbs TEA/ton 3 lbs TEA/ton4 lbs TEA/ton 5 lbs TEA/ton

BA

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Effect of VOC Loss on RTO Cost

Cost effectiveness varies with catalyst usage and 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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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 on catalyst usage and resin losses.

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