**Param eter**  **January February**  **March Quarterly Total**  **April May**  **June Quarterly Total**  **July August**  **Septem ber** **Quarterly Total October**  **Novem ber** **Decem**

**ber Quarterly** 

**Total YTD**  **Param eter**  **Coke Content (% by wt)**  72.80% 72.80% 72.50% 72.50% 72.50% 72.49% 72.44% 72.19% 71.93% 72.24% 72.26% 72.56% 72.43%**Coke Content (% by wt)**  **Coke Sulfur (by wt)**  0.0187 0.0179 0.0201 0.0219 0.0174 0.0229 0.0204 0.0167 0.0185 0.0249 0.0235 0.0225 0.0204 **Coke Sulfur (by wt)**  **Pitch Content (% by wt)**  27.20% 27.20% 27.50% 27.50% 27.50% 27.51% 27.56% 27.81% 28.07% 27.76% 27.74% 27.44% 27.57%**Pitch Content (% by wt)**  **Pitch Sulfur Content (by**  **wt.)** 0.0054 0.0054 0.0054 0.0054 0.0054 0.0054 0.0054 0.0054 0.0054 0.0054 0.0054 0.0054 0.0054 0.0054**Pitch Sulfur Content (by wt.)**  **S Generation Rate (lb S/lb paste)**  0.0151 0.0145 0.0161 0.0174 0.0141 0.0181 0.0163 0.0136 0.0148 0.0195 0.0185 0.0178 0.0163**S Generation Rate (lb S/lb paste)** 

**SO 2** **Generation (lb SO2/lb briquettes)**  0.0276 0.0266 0.0295 0.0318 0.0258 0.0332 0.0299 0.0249 0.0272 0.0358 0.0339 0.0327 0.0299 **SO 2** **Generation (lb SO2/lb paste)**  **COS Generation Rate (lb COS/lb**  **paste)** 0.0023 0.0022 0.0025 0.0027 0.0022 0.0028 0.0025 0.0021 0.0023 0.0030 0.0028 0.0027 0.0025**COS Generation Rate (lb COS/lb paste)**  **Briquettes Poured (MT)**  5709.28 5789.29 5185.01 5813.06 5842.27 5483.39 5994.59 5441.66 5641.96 6098.91 4780.23 5625.27 67,405
**Unused Carbon (MT)**  115 115 115 115 115 115 115 115 115 115 115 115 1,380 **Briquettes Poured (lbs)**  **Briquettes Poured (lbs)**  12,333,278 12,509,670 11,177,461 12,562,074 12,626,471 11,835,276 12,962,279 11,743,277 12,184,863 13,192,26610,285,07312,148,068 145,560,057**Adujusted Briquette Consum**  **ption (lbs) Aluminum**  **Production lbs** 22,788,067 21,372,680 22,751,23066,911,977 21,954,647 23,083,976 22,233,849 67,272,472 22,489,075 22,598,080 22,322,50367,409,65822,447,90522,048,03722,546,55267,042,494268,636,601**Aluminum Production lbs**  **Aluminum Production Tons**  11,394 10,686 11,376 33,456 10,977 11,542 11,117 33,636 11,245 11,299 11,161 33,705 11,224 11,024 11,273 33,521 134,318**Aluminum Production Tons**  **COS Generation Rate (lb COS/Ton**  **Al)** 2.50 2.61 2.43 3.05 2.37 2.96 2.88 2.17 2.49 3.52 2.65 2.96 2.72**COS Generation Rate (lb COS/Ton Al)** 
**SO2 Generation (lb SO2/Ton Al)**  29.90 31.14 28.97 36.44 28.26 35.34 34.42 25.91 29.69 42.04 31.59 35.28 32.41 **SO2 Generation (lb SO2/Ton Al)**  **Pot Capture Efficiency**  93% 93% 93% 93% 93% 93% 93% 93% 93% 93% 93% 93% 93.0% **Pot Capture Efficiency**  **Control Efficiency SO2**  96% 96% 96% 96% 96% 96% 96% 96% 96% 96% 96% 96% 96.3% **Control Efficiency SO2**  **Overall Control SO2**  90% 90% 90% 90% 90% 90% 90% 90% 90% 90% 90% 90% 89.6%**Overall Control SO2 Control Efficiency**  **COS** 34% 34% 34% 34% 34% 34% 34% 34% 34% 34% 34% 34% 34.2% **Control Efficiency COS**  **Overall Control COS**  31% 31% 31% 31% 31% 31% 31% 31% 31% 31% 31% 31% 30.6%**Overall Control COS Prim** **ary Control (lb SO2/ton Al)**  1.03 1.07 1.00 1.25 0.97 1.22 1.18 0.89 1.02 1.45 1.09 1.21 1.12 **Prim ary Control (lb**  **SO2/ton Al) Prim** **ary Control (lb SO2)**  11,721 11,452 11,341 13,764 11,223 13,519 13,317 10,073 11,403 16,235 11,984 13,685 **149,717 Prim** **ary Control (lb SO2)**  **Roof Vent (lb SO2/ton Al)**  2.09 2.18 2.03 2.55 1.98 2.47 2.41 1.81 2.08 2.94 2.21 2.47 2.27 **Roof Vent (lb SO2/ton Al)**  **Roof Vent (lb SO2)** 23,844 23,296 23,072 27,999 22,830 27,501 27,091 20,492 23,197 33,027 24,380 27,839 **304,568 Roof Vent (lb SO2)**  **Total SO2** 35,565 34,748 34,413 104,726 41,763 34,053 41,019 116,835 40,408 30,565 34,600 105,573 49,262 36,364 41,524 127,151 **454,285 Total SO2**  **Prim ary Control**  **(lb COS/ton Al)** 1.53 1.60 1.49 1.87 1.45 1.81 1.76 1.33 1.52 2.16 1.62 1.81 1.66 **Prim ary Control (lb**  **COS/ton Al) Prim** **ary Control (lb COS)**  17,462 17,061 16,897 20,506 16,720 20,141 19,840 15,008 16,989 24,188 17,855 20,388 **223,055 Prim** **ary Control (lb COS)**  **Roof Vent (lb COS/ton Al)**  0.18 0.18 0.17 0.21 0.17 0.21 0.20 0.15 0.17 0.25 0.19 0.21 0.19 **Roof Vent (lb COS/ton Al)**  **Roof Vent (lb COS)** 1,998 1,952 1,933 2,346 1,913 2,304 2,270 1,717 1,943 2,767 2,042 2,332 **25,515 Roof Vent (lb COS)**  **Total COS** 19,460 19,013 18,830 57,303 22,852 18,633 22,444 63,929 22,110 16,724 18,932 57,766 26,955 19,897 22,721 69,573 **248,571 Total COS**  

# East Plant - 2008 Sulfur Dioxide and Carbonyl Sulfide Emissions by Month

**Pitch sulfur level - used the average for 2008 for each m onthly value. In 2008, the briquette consum**  **ption was based off the num ber of paste boxes dum** 

**ped on the pots as tracked by the carbon process engineer. Unused carbon was subtracted from briquettes**  **consum ed as it was sent offsite for recycling.**  

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