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Gossman Consulting, Inc

GCI TECH NOTES©


Volume 7, Number 2           A Gossman Consulting, Inc. Publication        May  2002


 

HWC Operating Limit Determination for Lone Star Industries Greencastle Facility

by

Jim Woodford and David Constans, Gossman Consulting, Inc.

Craig Chrispell and Carlos Buckelew, Lonestar Industries

 


In 1991 & 1992, boilers and industrial furnaces faced EPA regulation for their hazardous waste burning activity.  In fact, this led to the steel mills dropping the activity.  The BIF rule, as it came to be called, was designed to protect human health and the environment.  But over the years, the rules kept getting more and more attention.  EPA Administrator Carol Browner even managed to flip-flop waste disposal priorities and whereas burning waste and getting rid of it had once been at the top, that activity now found itself at the bottom with land fills coming back in favor.  Over the past several years, EPA has been developing MACT rules for boilers and industrial furnaces and now the industry faces new limits with some new ways of calculating how you meet those limits.  Some BIFs wondered how their existing BIF (or final permit) data would fare without doing new testing. This paper looks at one facility’s compliance data from late 2000 in order to determine how that data stacks up under the 2002 waste combustor MACT rules.

 

REQUIREMENTS OF THE HWC REGULATION

The first thing to do is take a look at the waste/combustor rule (as of April 2002) and compare requirements with BIF.  If two or more test sequences are needed to complete all the required tests and there are subsequently two or more sets of data for a particular operating parameter the more stringent is applied as the operating limit.  As an example both the DRE test and the PCDD/PCDF test require the establishment of a minimum combustion chamber temperature, whichever test sequence gives the higher average of run averages establishes the limit.

 

These are the operating limits to be considered:

Minimum Combustion Chamber Temperature

DRE Test - Operating Limit will be an HRA (hourly rolling average) greater than the average of the run averages.  PCDD/PCDF Test – Same

Maximum Flue Gas Flow Rate or Production Rate

DRE Test – Operating Limit will be an HRA less than the average of the maximum HRA for the runs.   PCDD/PCDF Test, SVM/LVM Test and Chloride Test – Same

Maximum Liquid HWF Feed Rate

DRE Test - Operating Limit will be an HRA less than the average of the maximum HRA for the runs.  PCDD/PCDF Test – Same

Maximum Total HWF Feed Rate

DRE Test - Operating Limit will be an HRA less than the average of the maximum HRA for the runs.  PCDD/PCDF Test – Same

Maximum APCD Inlet Temperature

PCDD/PCDF Test - Operating Limit will be an HRA less than the average of the run averages.

SVM/LVM Test – Same

Element Feed Rate Limits

Mercury Feed Rate - Operating Limit will be a 12 HRA less than the average of the average HRA for the runs.  SVM/LVM Feed Rate – Same.  Chloride Feed Rate - Same

Minimum Power Limits for ESPs

This requirement was dropped from the rule in an amendment in the May 14, 2001 FR

Minimum Pressure Drop Limits for Baghouses

This requirement was dropped from the rule in an amendment in the May 14, 2001 FR

Maximum Combustion Chamber Pressure

Pressure must be less than ambient pressure

Maximum CO (max 100 ppmv) or THC (max 20 ppmv) in the Stack

Monitoring is the same as BIF, i.e. PS4B and PS8A.  Note: If CO is chosen as the standard the POHC test must demonstrate a <20 ppmv of THC in the stack gases. 

The next thing on the agenda is to look at existing compliance data and run it through the limit setting exercises of the HWC MACT rule.


 

IMPACT OF “AVERAGE OF RUN AVERAGES” ON OPERATING ENVELOPE SPECIFIC TO GREENCASTLE

Using actual 2000 ROC test the differences in establishing the various parameters are demonstrated.

 

BIF Operating Values

HWC MACT Operating Values

Minimum Combustion Chamber Temp. °F

Run 1, Min HRA,   1682

Run 2, Min HRA,   1675

Run 3, Min HRA,   1675

Avg.  Min HRA,     1678

Minimum Combustion Chamber Temp. °F

Run 1, Avg.          1723

Run 2, Avg.          1722

Run 3, Avg.          1720

Avg. of Averages  1722

Maximum Kiln Feed Feedrate, tons(wet)/hr

Run 1, Max HRA,    458

Run 2, Max HRA,    462

Run 3, Max HRA,    458

Avg. Max HRA,       460

Maximum Kiln Feed Feedrate, tons(wet)/hr

Run 1, Max HRA,    458

Run 2, Max HRA,    462

Run 3, Max HRA,    458

Avg. Max HRA,       460

Maximum ID Fan (alternate to feedrate), RPM

Run 1, Max HRA, 897

Run 2, Max HRA, 899

Run 3, Max HRA, 904

Avg. Max HRA,    900

Maximum ID Fan (alternate to feedrate), RPM

Run 1, Max HRA, 897

Run 2, Max HRA, 899

Run 3, Max HRA, 904

Avg. Max HRA,    900

Maximum Liquid HWF Feedrate, tons/hr

Run 1, Max HRA  12.6

Run 2, Max HRA  13.5

Run 3, Max HRA  13.2

Avg, Max HRA     13.1

Maximum Liquid HWF Feedrate, tons/hr

Run 1, Max HRA  12.6

Run 2, Max HRA  13.5

Run 3, Max HRA  13.2

Avg, Max HRA     13.1


BIF Operating Values

HWC MACT Operating Values

Maximum Total HWF Feedrate, tons/hr

Run 1, Max HRA  12.8

Run 2, Max HRA  13.7

Run 3, Max HRA  13.4

Avg, Max HRA     13.3

Maximum Total HWF Feedrate, tons/hr

Run 1, Max HRA  12.8

Run 2, Max HRA  13.7

Run 3, Max HRA  13.4

Avg, Max HRA     13.3

Maximum ESP Inlet Temperature, °F

Run 1, Max HRA   416

Run 2, Max HRA   428

Run 3, Max HRA   432

Avg. Max HRA      426

Maximum ESP Inlet Temperature, °F

Run 1, Avg.          401

Run 2, Avg,          414

Run 3, Avg.          405

Avg. of Averages  407

Maximum By-Pass APCD Inlet Temperature, °F

Run 1, Max HRA   426

Run 2, Max HRA   430

Run 3, Max HRA   424

Avg. Max HRA      427

Maximum By-Pass APCD Inlet Temperature, °F

Run 1, Avg.          389

Run 2, Avg,          386

Run 3, Avg.          395

Avg. of Averages  390

 

ELEMENT FEEDRATE LIMITS

 

2000 ROC Maximum HRA Rates

HWC MACT Operating Limits

 

 

As LVM (As + Be + Cr)

110 #/hr

If set based on 2000

ROC data

Same Data Monitored over a 12 HRA

 

LVM – 106.4 #/hr

104.9 #/hr



As SVM (Pb + Cd)

43 #/hr

SVM – 41.8 #/hr

41.2 #/hr


Chlorine

712 #/hr

Chlorine– 622.3 #/hr

579.4 #/hr

 

 

The set point for the SVM, LVM, Hg and chlorine feedrate limits under the HWC MACT is the average of the three run average HRA input rates. In this case, the 2000 ROC mercury data is insufficient to provide an input rate limit primarily due to concentration values less than detection limit, especially for the raw feed materials.  Under BIF it was unnecessary to have a precise input value for mercury from raw materials.  HWC requirements are however more stringent.  HWC does still have a provision similar to BIF’s Tier IA.  See 63.1207(m) where an MTEC may be calculated.  Amendments to the HWC MACT have also been made which ease the requirements on how non-detects are handled. See FR 66 No. 128 page 35098.    Clearly the 12 HRA will flatten the data. 

ADDRESSING EACH MONITORED PARA-METER IN TURN:

Minimum Combustion Chamber Temperature – The lower the value the better.  The ideal would be to run as low of a temperature as possible during both the DRE and PCDD/PCDF tests.  At the same time however we would want to maximize flue gas flow rate (or production), HWF feed rate and during the PCDD/PCDF test maximize the APCD inlet temperature. (Although maximizing production rate as an alternate for maximum flue gas flow rate will likely be difficult and still minimize combustion chamber temperature.)  This should be possible but it will be necessary to sit down and work out the desired values, compromising as required, and plan out how this can be done.

 

Maximum Flue Gas Flow Rate – This will be somewhat easier because the limit is to be a HRA less than the average of the maximum HRA of the test runs.  Here a large amplitude cycle will be an  advantage.

 

Maximum HWF Feed Rate – Because of the way the limit is set the only thing that can be done is to feed at a high rate throughout the test runs.  This can be a conflicting parameter with minimizing combustion chamber temperature for some kilns.

 

Maximum APCD Inlet Temperature – There is no upper limit on this value if the PCDD/DF is below 0.2 ng/dscm TEQ.  Even if it is necessary to comply with the >0.2 but <0.4 ng/dscm at 7% O2 and therefore limited to a maximum of 400 F (per the HWC MACT rule, 63.1204(a)(ii)) it is worth while, if possible, to establish a set of  “average of run averages” above 400 F so that 400 F is indeed the limit and not some value less than that like 398 F.  If however, it is necessary to be at, say 300 F, to be below 0.4 ng/dscm@7% O2 it is still worth while to maximize this temperature limit to provide as much operating envelope as possible.

 

Element Feed Rate – The 12 HRA limit flattens the data however it is still possible to exceed the limit, particularly if there is a pronounced cycle in the metals feedrate which is not accommodated in the run start and stop times.  Consistently feeding these elements at as high a rate as is allowable throughout the runs would be best.        

 

CONCLUSION

Waste Combustor MACT versus BIF makes little or no difference for maximum raw material feedrate, ID fan rpm, liquid HWF feedrate or maximum HWF feedrate.  There is clearly an impact on minimum combustion chamber temperature, maximum ESP inlet temperature and maximum by-pass APCD inlet temperature.  Clearly, a facility has more flexibility under the new rules, but each facility will still have to decide which operating parameter they choose to dictate operations.