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Metso Minerals (Pyro Division) , 350 Railorad St. Danville, PA, 17821 

# Technical Analysis for Tilden I Phase III additional simulations while applying COEN LNB technology.
Background Simulations 8 thru 11 are newly created simulations. This document provides an overview comparative analysis of simulations 8 thru 11, which is Phase III study for Tilden furnaces. Simulations 1 thru 3 were created in 2012 as part of Phase I study and were analyzed in a previous document. Simulations 4 thru 7 were created and analyzed in a previous document in 2013 as part of Phase II study. This document is created for the analysis of simulations 8 thru 11. This purpose of this analysis to use current operating data and apply it using the latest COEN LNB design conditions required for NOx reduction. Refer to COEN report titled “ Final report for Tilden Line 1 (T-1)” for design condition details. Simulations Phase Simulation Description Conditions
1 1 Baseline Current operating conditions on natural gas fuel with 15.5% stoichiometric primary combustion air
1 2 100% Stoich Current conditions with 110% stoichiometric primary combustion air along with adjusting cooler airflow to maintain 1150 ° F recouperation (recoup) temperature. See stream number 27. 1 3 110% Stoich Current conditions with 100% stoichiometric primary combustion air along with adjusting cooler airflow to maintain 1150 ° F recoup temperature.
2 4 100% Stoich Current conditions with 100% stoichiometric primary combustion air along with adjusting primary cooling and recoup airflow airflow to maintain same UDD and DDD exhaust gas volume flow. Grate UDD and DDD on gas temperatures were maintained the same as baseline simulation 1. 2 5 100% Stoich Current conditions with 100% stoichiometric primary combustion air along with adjusting primary cooling and recoup airflow airflow to minimize fuel consumption. 2 6 100% Stoich Current conditions with 100% stoichiometric primary combustion air along with increasing primary cooling and recoup airflow airflow by 10% above the flow established in Simulation 6.

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January 13, 2015

Metso Minerals (Pyro Division) , 350 Railorad St. Danville, PA, 17821 

# Phase Simulation Description Conditions
2 7 100% Stoich Current conditions with 100% stoichiometric primary combustion air along with increasing primary cooling and recoup airflow airflow by 20% above the flow established in Simulation 6. 3 8 New Gas

Baseline Current operating conditions on 100% natural gas

as measured and analyzed during the May 23, 2013 airflow study.
3 9 COEN Gas

Stoich Design Starting with new gas baseline simulation 8 and

adjust for latest COEN design information contained in report title” COEN final report report for Tilden 1 (T

- 1). The design data from COEN for 100% natural 3 10 New Coal/Gas

Baseline Current operating conditions on 76% coal and 24%

natural gas as measured and analyzed during the June 14, 2012 airflow study.
3 11 COEN Coal

Stoich Design Starting with new coal/gas baseline simulation 10

and adjust for latest COEN design information contained in report title” COEN final report report for Tilden 1 (T

- 1). The design data from COEN for
All engineering simulations were developed by holding several of the key process parameters used for Simulaton 8 thru 11. The process parameters held were production rate of pellets, % green ball moisture, bentonite, flux rate. . The total air supplied to the cooler was adjusted as needed to maintain final product temperature across all simulations. Maintaining these parameters ensures that fuel changes are not due to altered processing requirements. Holding these key process parameters also allows for comparison to previous simulations 1 thru 7. Comparitive Analysis Two comparison sets are analyzed. One set for comparing baseline gas with COEN LNB gas (simulation 8 compared to 9) and another set for comparing baseline coal with COEN LNB coal operation (simulation 10 compared to 11). Data values stated in below conclusions will have 8 and 9 values first followed by 10 and 11. The LNB COEN simulations were compared to the baseline simulation for several key p rocess parame t ers. NO x emissio n s valu es c an n ot be pr e d ic t e d for COEN simu lati o n s d u e to li m i t e d i n fo rma tion fro m b urner suppl i ers a n d w ou ld not b e a cc urate u n t il fu ll sc ale d emonstra tion te sti n g

. Dus t generati o n i s a ff ected b y p e ll et hea t up and cool d ow n rate s. D u st em iss ions (stre a m 1 2, 24, 6 5) w e re n o t comp a red f or CO EN si m u l ations b ecause o f the un c e rtai nt y of s e n sit ivi ty of the p e ll ets. Fur ther t e stin g is required t o d etermi n e dust genera tion. P lease r e fe r t o attac h e d ta ble s f or m ore c o mp ari sons and comments

. Con clu s io ns

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January 13, 2015

Metso Minerals (Pyro Division) , 350 Railorad St. Danville, PA, 17821 

# The comparison values when stated below are stated for gas comparison and then coal comparison respectively. The comparison of key process parameters shows a number of significant operational and environmental impacts as a result of COEN LNB installation: 1. Fuel rate is expected to increase 28% and 21%(stream 46) when incorporating LNB technology at Tilden I. The fuel rate increase is due to increased heat content in exhaust gases, i.e. heat generated but not used to processing pellets. The increase in unheated primary combustion air to the burner will require an increase in fuel to replace the heat not used from heated secondary combustion air. 2. A fuel rate increase is also shown between gas firing and coal firing in the kiln. The coal firing requires coal grinding mill air be supplied to the kiln burner This amount of air accounts for 47% of stoichiometric air requirements as compared to gas firing where only 16% stoichiometric air is supplied to kiln burner. The fuel rate between base coal firing and gas firing increases 11% due to this. This same phenomenon is the one that causes fuel rate to increase when applying COEN LNB burners to Tilden I. The significant increase in burner primary air alters the thermal heat balance of the system that requires more fuel to be used. 3. The pellet heat up rate is more aggressive using the LNB simulations. If testing confirms that detrimental pellet quality issues occur as a result, it will be necessary to blend outside air to reduce process gas temperatures in order to mimic a heat up rate closer to the base rate. This additional outside air will increase fuel rate further by increasing heat content in exhaust gases further. 4. The Down Draft Drying (DDD) (stream 24) exhaust gas volumes increased by 20% and 14% due to higher temperatures and increased air flow rates through the grate. The fans that move the DDD exhaust will see an increase in kilowatt usage by the percent of additional volume along with additional pressure requirements due to larger pressure losses in handling the extra volume. Computational Fluid Dynamics (CFD) modeling of process ducts is required to predict pressure requirements from handling the additional process air. The modeling will help determine if existing fan capacity can handle the increased volume and pressure requirements. 5. Burner primary air rate increased 709% and 247%. This increase was due to the COEN LNB burner requirements of 112% and 116% stoichiometric air rate requirements. The burner primary air rate increase is 40% and 35% of the base primary cooling air. Since the burner primary air rate is such a large portion of the primary cooling the primary cooling air had to be reduced to accommodate the rest of the system.. See below for more explanation. 6. Primary cooling air rate decreased 55% and 60%. This was due to the increase in kiln burner primary air rate. The grate and process fans that receive this process gas stream cannot handle the increase in gas flow by using same base primary cooling air rate along with additional burner primary air rate. 7. The split of cooling air between primary and secondary cooling will change drastically. Although the same amount of total process cooling air to cool the product is required for LNB technology, the split of cooling air between the zones in the cooler will change. This

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Metso Minerals (Pyro Division) , 350 Railorad St. Danville, PA, 17821 

# change in cooling air split will alter the cooling down cycle of the pellets. Altering the cool down cycle may affect pellet quality and dust generation. Secondary cooling air will increase while primary cooling air is decreased to accommodate LNB technology requirements of high burner primary air. Evaluation of the secondary cooling air fan will determine if it can handle the increased flow requirements. 8. The drastic change of the split between primary and secondary cooling will require rezoning of the cooler air. Secondary cooling air has increased so much from original design area that the velocity of cooling air through the pellet bed will start to fluidize the pellets. Fluidized pellets in the cooler lead to hot spots, thermal inefficiencies, and safety issues from handling hot pellets. The increased velocity requires higher underbed pressure to supply this increased airflow through the original area. The secondary cooling underbed windbox pressure will increase above ” WC while the primary cooling pressure drops to around ” WC. The imbalance of pressure between primary and secondary cooling along with the high secondary cooling air velocity require the cooler area to be rezoned. When rezoning the cooler the location of the gas off-takes such as parallel flow duct, recoup duct, cooler stack will have to relocated. 9. Secondary cooling air exiting the cooler vent stack is projected to increase between 415% and 360%. This increase in volume of air required to maintain total cooling air will exit the cooler vent stack (stream number 65). The collateral impact to the process, pellet quality, and a potential increase in dust loading, will be an important variable to assess during the full scale demonstrations. 10. Dust emissions from UDD and DDD exhaust gas are expected to increase. Dust emissions increases will be contributable to two key process changes with LNB technology: process dust generation from altered heat up rate and gas cleaning equipment efficiency due to gas volume increase through the equipment. The higher volumes of air through the gas cleaning equipment increases velocities which may stress existing cleaning systems and may decrease cleaning efficiency. 11. Process dust generation from altered heating and cooling rates may change the dust loading to UDD and DDD exhaust gas cleaning equipment. Changes to dust loading at the gas cleaning equipment may increase the burden on control equipment and may change stack particulate emissions. Process dust generation is not predictable until the sensitivity of pellets has been tested. Since the heat-up and cool down profile will change with LNB technology, it is expected that dust loading to the control equipment may increase. Evaluation of gas cleaning equipment is required to predict exhaust particulate. 12. Process gas (secondary combustion air) flow rates and temperatures entering the kiln from the primary cooling zone will be affected. Individual Computational Fluid Dynamics (CFD) analysis is required to fully understand the effects of LNB technology on kiln burner combustion zone because each GK system has unique temperatures, flow rates, velocities, and blends between the two ports. Expected impacts include but are not limited to: flame temperature profile, heat release curve, products of combustion rates, pollutant formations such as NOx, and CO. Since GK systems are custom designed, an individual furnace analysis is crucial to determine what effects will occur when applying LNB technology.

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Metso Minerals (Pyro Division) , 350 Railorad St. Danville, PA, 17821 

# 13. LNB technology alters heat up profile. It is recommended that testing and analysis be performed to determine what product quality issues are affected. Without further testing Metso, as a designed of GK systems, cannot guarantee the effects to product quality and production rate without more in depth study. 14. LNB burner technology alters flame temperature profile. This flame temperature profile is critical to obtaining proper time at temperature to produce pellets of proper qualities. The final sintering properties are very sensitive to peak temperature and time at temperature. Altering the flame temperature profile from the typical grate kiln temperature profile will alter pellet sintering quality. Metso cannot predict pellet quality changes due to flame temperature profile changes. 15. The increase in fuel requirements can be shown by the data in the heat loss rows Exhaust Gas Heat Loss, Grate Chain Heat Loss, and Total of these two rows. It is shown that the lower heat loss correlate to lower fuel rate. The cooler product discharge heat loss is equal for all simulations, therefore this heat loss was not shown. One of the goals of the simulations was to maintain product discharge temperature. 16. Increasing heat recovery from the cooler into the process does not always lead to lower fuel rates. The increased cooler heat recovery has to be recovered in kiln or grate in order for this to lower fuel rates. Passing the increased recover heat into the exhaust gases will not improve fuel rate. Process gas heat transfer in the grate bed is more efficient at higher temperatures and less mass as compared to lower temperatures and more mass if both carry the same amount of heat. 17. Kiln exit gas temperature was maintained at for all simulations. Because the flame pattern, heat release curve, length, etc is not known for LNB kiln burner combustion, the kiln heat transfer model was not adjusted for different flame characteristics. 18. DDD2 Grate on gas temperatures defined in base simulations is known to produce quality pellets. All LNB simulations have higher temperatures ϶ F and ϶ F. Some testing is required to determine the effect of this higher temperature on pellet quality. 19. NOx emissions on a MMBTU basis is expected to decrease from 74% (4.6 to 1.2) but NOx be dispersed into the environment will only decrease by 66%.
Final Conclusions The comparative analysis for Phase III of the applying Low NOX technology to Tilden I furnace shows similar conclusions as Phase I and Phase II. Using actual design parameters from the COEN report titled “Final report for Tilden Line 1 (T-1)” only solidifies the many obstacles, performance degradation, fuel penalty, energy penalties already mentioned in previous Phase I and Phase II analysis. Phase I and Phase II analysis was based on preliminary design information, while Phase III uses vendor required design parameters to meet Low NOx operation. Attached: Tilden I process flow diagram Tilden I Data Table, actual data Tilden I Data Table, normalized data

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Metso Minerals (Pyro Division) , 350 Railorad St. Danville, PA, 17821Simulation 8 Simulation 9 Simulation 10 Simulation 11

Criteria Units No. Actual Actual Actual Actual

Production Rate Lton/hr 67

Fuel Rate BTUg/LTon 46 Primary Air % of stoich 47 Primary Air lb/min 47 Secondary Air Temperature (°F) 45 Primary Cooling Air lb/min Secondary Cooling Air lb/min Secondary Air Vol. Flow Rate (ACFM) 45

Grate PH bed air flow SCFM/grate ft2 36

Recoup Gas Temperature (°F) 27 DDD2 On Gas Temperature (°F) Grate pellet disharge Temperature (°F) 44 Cooler pellet discharge Temperature (°F) 67

Exhaust Gas Heat Loss Heat Content (MBTU/min.) 12,24,65

Grate Chain Heat Loss Heat Content (MBTU/min.)

Total Heat Content (MBTU/min.) UDD Exhaust Gas CO2 (lb/min.) 12 H2O (lb/min.) 12 N2 (lb/min.) 12 O2 (lb/min.) 12 SO2 (lb/min.) 12 NOx (lb/min.) 12 Dust (lb/min.) 12 Mass Flow Rate (lb/min.) 12 Vol. Flow Rate (SCFM) 12 Vol. Flow Rate (ACFM) 12 Temperature (°F) 12 Heat Content (MBTU/min.) 12 DDD Exhaust Gas CO2 (lb/min.) 24 H2O (lb/min.) 24 N2 (lb/min.) 24 O2 (lb/min.) 24 SO2 (lb/min.) 24 NOx (lb/min.) 24 Dust (lb/min.) 24 Mass Flow Rate (lb/min.) 24 Vol. Flow Rate (SCFM) 24 Vol. Flow Rate (ACFM) 24 Temperature (°F) 24 Heat Content (MBTU/min.) 24 Cooler Stack Gas CO2 (lb/min.) 65

H2O (lb/min.) 65

N2 (lb/min.) 65

O2 (lb/min.) 65 SO2 (lb/min.) 65 NOx (lb/min.) 65 Dust (lb/min.) 65
Mass Flow Rate (lb/min.) 65
Vol. Flow Rate (SCFM) 65
Vol. Flow Rate (ACFM) 65 Temperature (°F) 65 Heat Content (MBTU/min.) 65
Note: No. denotes stream flow number for Tilden ICriteria Units No.

Production Rate Lton/hr 67

Fuel Rate BTUg/LTon 46 Primary Air % of stoich 47 Primary Air lb/min 47 Secondary Air Temperature (°F) 45 Primary Cooling Air lb/min Secondary Cooling Air lb/min Secondary Air Vol. Flow Rate (ACFM) 45

Grate PH bed air flow SCFM/grate ft2 36

Recoup Gas Temperature (°F) 27 DDD2 On Gas Temperature (°F) Grate pellet disharge Temperature (°F) 44 Cooler pellet discharge Temperature (°F) 67

Exhaust Gas Heat Loss Heat Content (MBTU/min.) 12,24,65

Grate Chain Heat Loss Heat Content (MBTU/min.)

Total Heat Content (MBTU/min.) UDD Exhaust Gas CO2 (lb/min.) 12 H2O (lb/min.) 12 N2 (lb/min.) 12 O2 (lb/min.) 12 SO2 (lb/min.) 12 NOx (lb/min.) 12 Dust (lb/min.) 12 Mass Flow Rate (lb/min.) 12 Vol. Flow Rate (SCFM) 12 Vol. Flow Rate (ACFM) 12 Temperature (°F) 12 Heat Content (MBTU/min.) 12 DDD Exhaust Gas CO2 (lb/min.) 24 H2O (lb/min.) 24 N2 (lb/min.) 24 O2 (lb/min.) 24 SO2 (lb/min.) 24 NOx (lb/min.) 24 Dust (lb/min.) 24 Mass Flow Rate (lb/min.) 24 Vol. Flow Rate (SCFM) 24 Vol. Flow Rate (ACFM) 24 Temperature (°F) 24 Heat Content (MBTU/min.) 24 Cooler Stack Gas CO2 (lb/min.) 65

H2O (lb/min.) 65

N2 (lb/min.) 65

O2 (lb/min.) 65 SO2 (lb/min.) 65 NOx (lb/min.) 65 Dust (lb/min.) 65
Mass Flow Rate (lb/min.) 65
Vol. Flow Rate (SCFM) 65
Vol. Flow Rate (ACFM) 65 Temperature (°F) 65 Heat Content (MBTU/min.) 65 Simulation 8 Simulation 9 Simulation 10 Simulation 11 Comments Normalized Normalized Normalized Normalized

1.00 1.00 1.00 1.00 System flow resistance and existing fan characteristics to be evaluated to determine if production rate can be maintained

1.00 1.28 1.00 1.21 Fuel rate increases for LNB simulation due to increase in unrecovered heat in exhaust gas streams

1.00 7.09 1.00 2.47 Primary air rate was adjusted to represent a reasonable range of primary air for LNB technology

1.00 9.10 1.00 3.09 Primary air rate was adjusted to represent a reasonable range of primary air for LNB technology

0.00 326.86 0.00 286.72 Temperature increased greatly due to decreased air flow through primary cooling zone.

1.00 0.55 1.00 0.60 Primary cooling decreases due to increase in LNB burner primary air rate.

1.00 1.50 1.00 1.54 Secondary cooling increases to maintain final product temperature

1.00 0.63 1.00 0.66 Flow rate decreases due to air is displaced by additional primary air requirements for LNB technology.

1.00 0.96 1.00 0.96 Simulation 3 airflow was increased to reduce "Recoup Gas" temperature

0.00 568.83 0.00 509.19 Recoup gas temperature increases greatly. More testing is required to determine if pellet quality will be effected. 0.00 569.15 0.00 509.50

0.00 56.02 0.00 41.09 Temperature increased leading to higher grate chain temperatures and degraded chain life. 0.00 -5.88 0.00 -0.83

1.00 1.69 1.00 1.47 This is total heat leaving with UDD, DDD and cooler stack exhaust.

1.00 1.63 1.00 1.32 This is estimated heat loss from grate chain. The

1.00 1.68 1.00 1.45 1.00 0.96 1.00 1.19
1.00 1.08 1.00 1.13 Increased due to higher percentage of drying occuring in UDD zone. 1.00 0.91 1.00 1.10 1.00 0.84 1.00 1.07 TBD TBD TBD TBD
TBD TBD TBD TBD Nox generation values not available from burner supplier
TBD TBD TBD TBD Dust generation is effected by pellet heat up rate. Further testing required
1.00 0.92 1.00 1.10
1.00 0.93 1.00 1.10
1.00 0.95 1.00 1.11 Volume increased due to higher temperatures. Fan performance must be evaluated.
0.00 16.82 0.00 7.24 Temperature increased leading to increase in unrecovered heat leaving the system.
1.00 1.02 1.00 1.15 Increase in unrecovered heat. 1.00 1.30 1.00 1.20 Increased due to increase in fuel rate. 1.00 1.04 1.00 0.98 1.00 1.04 1.00 1.06 1.00 1.00 1.00 1.04 TBD TBD TBD TBD
TBD TBD TBD TBD Nox generation values not available from burner supplier
TBD TBD TBD TBD Dust generation is effected by pellet heat up rate. Further testing required
1.00 1.04 1.00 1.05
1.00 1.04 1.00 1.05
1.00 1.20 1.00 1.14 Volume increased due to higher temperatures. Fan performance must be evaluated.
0.00 105.17 0.00 64.60 Temperature increased leading to increase in unrecovered heat leaving the system.
1.00 1.59 1.00 1.31 Increase in unrecovered heat. 1.00 1.00 1.00 1.00

1.00 3.15 1.00 3.10 Air flow rate increased to compensate for reduced air flow to primary cooling required to maintain cooler pellet discharge temperature.

1.00 3.15 1.00 3.10 Air flow rate increased to compensate for reduced air flow to primary cooling required to maintain cooler pellet discharge temperature.

1.00 3.15 1.00 3.10 Air flow rate increased to compensate for reduced air flow to primary cooling required to maintain cooler pellet discharge temperature. TBD TBD TBD TBD TBD TBD TBD TBD
TBD TBD TBD TBD Dust generation is effected by pellet heat up rate. Further testing required

1.00 3.14 1.00 3.09 Air flow rate increased to compensate for reduced air flow to primary cooling required to maintain cooler pellet discharge temperature.

1.00 3.15 1.00 3.10 Air flow rate increased to compensate for reduced air flow to primary cooling required to maintain cooler pellet discharge temperature.

1.00 4.15 1.00 3.60 Air flow rate increased to compensate for reduced air flow to primary cooling required to maintain cooler pellet discharge temperature.
0.00 186.54 0.00 115.17 Temperature increased leading to increase in unrecovered heat leaving the system.
1.00 13.89 1.00 5.11 Increase in unrecovered heat. Note: All values except temperatures have been normalized to base simulation. Temperatures are shown as degrees