Reference Charts & Graphs Feature Article Digest€¦ · 6 February 2008 - IndustrialHeating.com General Engineering Data 500.0 260 126.67 503.6 262 127.78 507.2 264 128.89 510.8

A Publication • www.industrialheating.com • 23,030 Circulation • The Largest And Most Preferred Industry Publication

A Publication • www.industrialheating.com • 23,030 Circulation • The Largest And Most Preferred Industry Publication

February 2008

Reference Charts & Graphs Feature Article Digest

• Burners • Analysis & Control • Performance & Efficiency

An informative reference guide for the thermal processing industry containing helpful reference tools and a digest of useful combustion-related articles.

A Supplement to Industrial Heating

Excerpts from

IndustrialHeating.com - February 2008 5

Contents

Throughout the Tool Kit, you will fi nd helpful hints from Eclipse’s “20 Tips for Combustion System Care” booklet. The tips will be numbered as they appear in this resource.

For Combustion System Care20

TIPS

February 2008

Reference Charts & GraphsGeneral Engineering Data PageTemperature Conversion Chart ...........................................................................................................6Thermal Properties of Various Materials ......................................................................................... 8Approximate Critical Temps of Carbon and Alloy Steels ......................................................... 10Equilibrium Curves for Furnace Gases on Iron, Carbon & Steels ............................................11

Industrial GasesConversion Table of Pressure Equivalents .................................................................................... 12Various Relationships for Flow & Pressure .................................................................................... 12Table for Atmosphere Classiÿ cations ............................................................................................. 12Compositions & Characteristics for Prepared Atmospheres.................................................. 13

Fuels and Flue DataAvailable Heat for Natural Gas .......................................................................................................... 14Typical Fuels Data .................................................................................................................................. 14Hot Mix Temperature vs % Excess Air ............................................................................................. 14Emissions Conversion Chart ............................................................................................................... 15Flue Gas Component Data .................................................................................................................. 15Heat Recovery and Fuel Savings ...................................................................................................... 16

Feature Article DigestBurnersSelf-Regenerative BurnersDr. Joachim G. Wuenning – WS Thermal Process Technology Inc., Elyria, Ohio .................... 18

Converting Your Process To Alternative Renewable FuelsGordon Harbison, Dürr Systems, Inc., Plymouth, Mich., and George Fritts, Eclipse, Inc., Rockford, Ill. ..............................................................................................................................................20

Analysis & ControlOptimizing Combustion ControlsDan Curry – Eclipse, Inc., Rockford, Ill. ..............................................................................................22

ROI Analysis of Combustion Control for Gas-Fired Heat-Treating FurnacesE.S. Boltz, Y.H. Boltz, B. Knight and P.J. Barker – Marathon Sensors Inc., a member of United Process Controls ......................................................................................................................................24

Performance & Effi ciencyAlternative Energy SavingsSteeltech Limited – Grand Rapids, Mich. ..........................................................................................26

Courtesy of

14

18

400% 200%

300%

50%

100%25%

0%

10%

Oxygen

0 1 2 3 4 5 6Oxygen % in fl ue gas

High-effi ciency region

Fuel

CO

24

6 February 2008 - IndustrialHeating.com

GeneralEngineering Data

500.0 260 126.67 503.6 262 127.78 507.2 264 128.89 510.8 266 130.00 514.4 268 131.11 518.0 270 132.22 521.6 272 133.33 525.2 274 134.44 528.8 276 135.56 532.4 278 136.67 536.0 280 137.78 539.6 282 138.89 543.2 284 140.00 546.8 286 141.11 550.4 288 142.22 554.0 290 143.33 557.6 292 144.44 561.2 294 145.56 564.8 296 146.67 568.4 298 147.78 572.0 300 148.89 575.6 302 150.00 579.2 304 151.11 582.8 306 152.22 586.4 308 153.33 590.0 310 154.44 593.6 312 155.56 597.2 314 156.67 600.8 316 157.78 604.4 318 158.89 608.0 320 160.00 611.6 322 161.11 615.2 324 162.22 618.8 326 163.33 622.4 328 164.44 626.0 330 165.56 629.6 332 166.67 633.2 334 167.78 636.8 336 168.89 640.4 338 170.00 644.0 340 171.11 647.6 342 172.22 651.2 344 173.33 654.8 346 174.44 658.4 348 175.56 662.0 350 176.67 665.6 352 177.78 669.2 354 178.89 672.8 356 180.00 676.4 358 181.11 680.0 360 182.22 683.6 362 183.33 687.2 364 184.44 690.8 366 185.56 694.4 368 186.67 698.0 370 187.78

701.6 372 188.89 705.2 374 190.00 708.8 376 191.11 712.4 378 192.22 716.0 380 193.33 719.6 382 194.44 723.2 384 195.56 726.8 386 196.67 730.4 388 197.78 734.0 390 198.89 737.6 392 200.00 741.2 394 201.11 744.8 396 202.22 748.4 398 203.33 752.0 400 204.44 755.6 402 205.56 759.2 404 206.67 762.8 406 207.78 766.4 408 208.89 770.0 410 210.00 773.6 412 211.11 777.2 414 212.22 780.8 416 213.33 784.4 418 214.44 788.0 420 215.56 791.6 422 216.67 795.2 424 217.78 798.8 426 218.89 802.4 428 220.00 806.0 430 221.11 809.6 432 222.22 813.2 434 223.33 816.8 436 224.44 820.4 438 225.56 824.0 440 226.67 827.6 442 227.78 831.2 444 228.89 834.8 446 230.00 838.4 448 231.11 842.0 450 232.22 845.6 452 233.33 849.2 454 234.44 852.8 456 235.56 856.4 458 236.67 860.0 460 237.78 863.6 462 238.89 867.2 464 240.00 870.8 466 241.11 874.4 468 242.22 878.0 470 243.33 881.6 472 244.44 885.2 474 245.56 888.8 476 246.67 892.4 478 247.78 896.0 480 248.89 899.6 482 250.00

903.2 484 251.11 906.8 486 252.22 910.4 488 253.33 914.0 490 254.44 917.6 492 255.56 921.2 494 256.67 924.8 496 257.78 928.4 498 258.89 932.0 500 260.00 935.6 502 261.11 939.2 504 262.22 942.8 506 263.33 946.4 508 264.44 950.0 510 265.56 953.6 512 266.67 957.2 514 267.78 960.8 516 268.89 964.4 518 270.00 968.0 520 271.11 971.6 522 272.22 975.2 524 273.33 978.8 526 274.44 982.4 528 275.56 986.0 530 276.67 989.6 532 277.78 993.2 534 278.89 996.8 536 280.00 1000.4 538 281.11 1004.0 540 282.22 1007.6 542 283.33 1011.2 544 284.44 1014.8 546 285.56 1018.4 548 286.67 1022.0 550 287.78 1040.0 560 293.33 1058.0 570 298.89 1076.0 580 304.44 1094.0 590 310.00 1112.0 600 315.56 1130.0 610 321.11 1148.0 620 326.67 1166.0 630 332.22 1184.0 640 337.78 1202.0 650 343.33 1220.0 660 348.89 1238.0 670 354.44 1256.0 680 360.00 1274.0 690 365.56 1292.0 700 371.11 1310.0 710 376.67 1328.0 720 382.22 1346.0 730 387.78 1364.0 740 393.33 1382.0 750 398.89 1400.0 760 404.44 1418.0 770 410.00

1436.0 780 415.56 1454.0 790 421.11 1472.0 800 426.67 1490.0 810 432.22 1508.0 820 437.78 1526.0 830 443.33 1544.0 840 448.89 1562.0 850 454.44 1580.0 860 460.00 1598.0 870 465.56 1616.0 880 471.11 1634.0 890 476.67 1652.0 900 482.22 1670.0 910 487.78 1688.0 920 493.33 1706.0 930 498.89 1724.0 940 504.44 1742.0 950 510.00 1760.0 960 515.56 1778.0 970 521.11 1796.0 980 526.67 1814.0 990 532.22 1832.0 1000 537.78 1850.0 1010 543.33 1868.0 1020 548.89 1886.0 1030 554.44 1904.0 1040 560.00 1922.0 1050 565.56 1940.0 1060 571.11 1958.0 1070 576.67 1976.0 1080 582.22 1994.0 1090 587.78 2012.0 1100 593.33 2030.0 1110 598.89 2048.0 1120 604.44 2066.0 1130 610.00 2084.0 1140 615.56 2102.0 1150 621.11 2120.0 1160 626.67 2138.0 1170 632.22 2156.0 1180 637.78 2174.0 1190 643.33 2192.0 1200 648.89 2210.0 1210 654.44

2228.0 1220 660.00 2246.0 1230 665.56 2264.0 1240 671.11 2282.0 1250 676.67 2300.0 1260 682.22 2318.0 1270 687.78 2336.0 1280 693.33 2354.0 1290 698.89 2372.0 1300 704.44 2390.0 1310 710.00 2408.0 1320 715.56 2426.0 1330 721.11 2444.0 1340 726.67 2462.0 1350 732.22 2480.0 1360 737.78 2498.0 1370 743.33 2516.0 1380 748.89 2534.0 1390 754.44 2552.0 1400 760.00 2570.0 1410 765.56 2588.0 1420 771.11 2606.0 1430 776.67 2624.0 1440 782.22 2642.0 1450 787.78 2660.0 1460 793.33 2678.0 1470 798.89 2696.0 1480 804.44 2714.0 1490 810.00 2732.0 1500 815.56 2750.0 1510 821.11 2768.0 1520 826.67 2786.0 1530 832.22 2804.0 1540 837.78 2822.0 1550 843.33 2840.0 1560 848.89 2858.0 1570 854.44 2876.0 1580 860.00 2894.0 1590 865.56 2912.0 1600 871.11 2930.0 1610 876.67 2948.0 1620 882.22 2966.0 1630 887.78 2984.0 1640 893.33 3002.0 1650 898.89

Exact temperature values may be found by interpolation. For example: To find °C for 5027°F

5000°F = 2760.0°C5050°F = 2787.8°C

(2787.8 - 2760.0)°C = 27.8 = 0.555 °C (5050 - 5000)°F 50.0 °F

5027 - 5000 = 27°F x 0.555°C = 14.99°C °F

5027°F = 2760.0 + 14.99 = 2774.99°C

°F °C °F °C °F °C °F °C °F °C

Temperature ConversionsThe general arrangement of this table was devised by Souveur and Boylston more than 40 years ago. The middle column of fi gures (in bold-faced type) contains the reading (°F or °C) to be converted. If converting from Fahrenheit to Centigrade, read the °C equivalent in the column headed “°C”. If converting from Centigrade to Fahrenheit, read the °F equivalent in the column headed “°F”. °C = 5/9(°F-32)



Air 0.0765 — — — 0.237 -311.0 91.7 Alcohol -Ethyl 49.26 0.232 -173.2 44.8 0.648 172.4 369.0 -Methyl 49.6 — -142.6 29.5 0.601 150.8 480.6 Alumina 243.5 0.197 3722 — — — — Aluminum 166.7 0.248 1214 169.1 0.252 3272 — Ammonia 32° 45.6 0.502 -83.0 195 1.099 -37.3 543.2 Andalusite 199.8 0.168 3290 — — — — Aniline 2.25 0.741 17.6 37.8 0.514 363 198 Antimony 422 0.054 1166 70.0 0.054 2624 — Asbestos 124-174 0.195 — — — — — Asphalt - Trinidad 97 0.55 190 — 0.55 — — - Gilsonite 67.5 0.55 300 — 0.55 — — Arsenic 357.6 0.082 Sublimes — — — — Babbitt - 75Pb 15Sb 10Sn — 0.039 462 26.2 0.038 — — - 84Sn 8Sb 8Cu — 0.071 464 34.1 0.063 — — Bakelite — 0.30 — — — — — Beryllium 113.8 0.50 2345 621.9 0.425 5036 — Bismuth 615 0.033 518 18.5 0.035 2606 — Borax 105.5 0.238 1366 — — — — Brass - 67Cu 33Zn 528 0.105 1688 71.0 0.123 — — - 85Cu 15Zn — 0.104 1877 84.4 0.116 — — - 90Cu 10Zn — 0.104 1952 86.6 0.115 — — Brick - Fireclay 137-150 0.240 — — — — — -Red 118 0.230 — — — — — -Silica 144-162 0.260 — — — — — Bronze - 90Cu 10Al — 0.126 1922 98.6 0.125 — — - 90Cu 10Sn — 0.107 1850 84.2 0.106 — — - 80Cu 10Zn 10Sn 534 0.095 1832 79.9 0.109 — — Cadmium 540 0.038 610 19.5 0.074 1412 409 Calcium 96.6 0.170 1564 — — 2709 — Calcium Carbonate 175 0.210 Dec. 1517 — — — — Calcium Chloride 157 0.16 1422 97.7 — >2912 — Camphor 62.4 0.440 353 19.4 0.61 408 — Carbon - Amorphous 129 0.241 6300 — — 8721 — - Disulfide 79.2 — -166 — 0.24 115 150.8 - Graphite 138.3 0.184 6300 — — 8721 — Charcoal 18-38 0.165 — — — — — Chlorine 0.190 0.19 -151 41.3 — -30.3 121 Chloroform 95.5 — -85 — 0.149 142.1 105.3 Chromite 281 0.22 3956 — — — — Chromium 437 0.12 2822 57.1 — 4500 — Clay, Dry 112-162 0.224 3160 — — — — Coal - Anthracite — 0.31 — — — — — - Bituminous — 0.30 — — — — — Coal Tar 76.7 0.413 196 — — 325 — Coal Tar Oil — — — — 0.34 390-910 136 Cobalt 555 0.145 2723 — — 5252 — Coke — 0.2-0.38 — — — — — Concrete — 0.27 — — — — — Copper 558 0.104 1982 90.8 0.111 4703 — Cork — 0.48 — — — — — Corundum 250 0.304 3722 — — 6332 — Die Cast Metal - 87.3Zn 8.1Sn 4.1Cu 0.5Al — 0.103 780 48.3 0.138 — — - 90 Sn 4.5 Cu 5.5 Sb — 0.070 450 30.3 0.062 — — - 80 Pb 10 Sn 10 Sb — 0.038 600 17.4 0.037 — — - 92 Al 8 Cu — 0.236 1150 163.1 0.241 — —

Thermal Properties of Various Materials(Reprinted with permission from “Combustion Engineering Guide,” published by Eclipse, Inc., Rockford, Ill., 1986).

MaterialDensitylb/cu.ft.@60°F

SolidSpecific

HeatBtu/lb-°F

MeltingPoint,

°F

LatentHeat ofFusion,Btu/lb

LiquidSpecific

Heat,Btu/lb-°F

BoilingPoint,

°F

LatentHeat of

VaporizationBtu/lb



Fuel Oil — — — — 0.45 — — Gasoline 42 — — — 0.514 176 128-146 German Silver — 0.109 1850 86.2 0.123 — — Glass - Crown — 0.16 — — — — — - Flint — 0.13 — — — — — - Pyrex — 0.20 — — — — — - Window (Soda Lime) 160 0.19 2192 — — — — Glass Wool 1.5 0.16 — — — — — Graphite 0.30-0.38 — Subl. 6606 — — — — Hydrochloric Acid 75 — -12 — — — — Hydrogen 0.0053 — -434 27 — -423 194 Hydrogen Sulfide — — -117 — — -79 — Iron 491 0.1162 2795 117 — 5430 — Iron - Gray Cast 443 0.119 2330 41.7 — — — - White Cast 480 0.119 2000 59.5 — — — Kerosene — — — — 0.470 — 108 Lead 711 0.032 621 9.9 0.032 3171 — Lead Oxide 575-593 0.049 1749 — — — — Lipowitz Metal — 0.041 140 17.2 0.041 — — Magnesite 187 0.200 Dec. 662 — — — — Magnesium 108.6 0.272 1204 83.7 0.266 — — Magnesium Oxide 223 0.23-0.30 5072 — — — — Manganese 500 0.171 2246 65.9 0.192 — — T = 1958 T = 43.5 Molybdenum 636 0.065 4748 — — 8672 — Monel 550 0.129 2415 117.4 0.139 — — Mallite 188.8 — 3290 — 0.175 — — Nickel 556 0.134 2646 131.4 0.124 — — Nichrome 517 — — — 0.111 — — Nitrogen 0.0741 — -346 11.1 — -320 85.6 Oxygen 0.0847 0.336 -361 5.98 0.394 -297 91.6 Petroleum 48-55 — — — 0.511 — — Platinum 1335 0.036 3224 49 0.032 7933 — Porcelain 150 0.26 — — — — — Quartz 165.5 0.23 — — — — — Resin - Phenolic 80-100 0.3-0.4 — — — — — - Copals 68.6 0.39 300-680 — — — — Rhodium 773 0.058 3571 — — — — Rockwool 6 0.198 — — — — — Rose’s Metal — 0.043 230 18.3 0.041 — — Rosin 68 0.5 170-212 — — — — Sand 162 0.20 — — — — — Sandstone — 0.22 — — — — — Silica 180 — 3182 — 0.1910 4060 — Silicon 155 0.176 2600 — — 4149 Silicon Carbide 199 0.23 4082 — — Subl. 3032 — Silver 656 0.063 1761 46.8 0.070 3634 — Sodium Carbonate 151.5 0.306 1566 — — Dec. — Sodium Nitrate 140.5 0.231 597 116.8 — 1716 — Sodium Oxide 142 0.231 Subl. 2327 — — — — Sodium Sulfate 168 0.21 — — — — — Solder - 50Pb 50Sn 580 0.051 450 23 0.046 — — - 63Pb 37Sn — 0.044 468 14.8 0.041 — — Steel - 0.3%C 491 0.166 (70-1330°)* *Phase change between 1330 & 1500° requires 0.129 (1500-2500°) additional 80 Btu/lb. Tin 460 0.069 450 25.9 0.0545 4118 — Titanium 281 0.14 3272 — — — — Tungsten 1204 0.034 6098 — — 10652 — Type Metal- Linotype — 0.036 486 21.5 0.036 — — Type Metal- Stereotype 670 0.036 500 26.2 0.036 — — Uranium 370 0.028 2071 — — — — Vanadium 372 0.115 3110 — — 5432 — Zinc 443 0.107 786 47.9 0.146 1706 — Zinc Oxide 341 0.125 >3272 — — — — Zircon 293 0.132 4622 — — — — Zirconia 349 0.103 4919 — — — — Zirconium 399 0.067 3100 — — 9122 —

MaterialDensitylb/cu.ft.@60°F

SolidSpecific

HeatBtu/lb-°F

MeltingPoint,

°F

LatentHeat ofFusion,Btu/lb

LiquidSpecific

Heat,Btu/lb-°F

BoilingPoint,

°F

LatentHeat of

VaporizationBtu/lb



1010 1335 1610 1560 1260 904 1015 1335 1585 1545 1260 871 1020 1335 1555 1515 1260 838 1025 1340 1545 1440 1265 805 1030 1340 1500 1465 1250 752 1035 1340 1475 1440 1255 720 1040 1340 1460 1420 1240 690 1045 1340 1440 1405 1260 655 1050 1340 1425 1390 1260 610 1055 1340 1390 1350 1260 590 1060 1340 1375 1340 1265 555 1065 1340 1350 1325 1270 501 1070 1340 1350 1310 1275 490 1080 1345 1355 1290 1280 415 1090 1345 1355 1290 1270 365 1095 1350 1415 1340 1210 628 1117 1350 1550 1450 1245 809 1118 1345 1520 1495 1245 782 1137 1315 1420 1360 1220 654 1141 1310 1400 1340 1210 628 1335 1315 1460 1340 1160 640 1340 1315 1435 1330 1150 610 2317 1285 1435 1265 1065 — 2330 1285 1380 1205 1050 — 2340 1285 1350 1185 1060 580 2345 1265 1335 1125 1040 — 2512 1290 1400 1150 1060 — 2515 1260 1400 1160 1090 — 3115 1355 1500 1480 1240 — 3120 1355 1480 1445 1230 — 3130 1355 1440 1355 1220 — 3140 1355 1410 1300 1215 630 3141 1355 1410 1300 1215 — 3150 1355 1380 1275 1215 —

3310 1335 1440 1235 1160 — 3316 1335 1425 1235 1160 — 4023 1350 1540 1440 1240 775 4027 1340 1485 1400 1240 755 4037 1340 1495 1390 1210 690 4047 1340 1440 1330 1200 615 4063 1360 1390 1220 1190 445 4130 1380 1490 1390 1250 685 4140 1350 1480 1370 1255 595 4145 1340 1470 1380 1250 569 4150 1350 1430 1345 1240 530 4320 1335 1490 1365 1170 720 4340 1335 1425 1310 1120 545 4615 1340 1510 1330 1210 — 4620 1325 1460 1300 1190 — 4640 1315 1400 1260 1130 640 4718 1320 1520 1410 1200 — 4820 1270 1440 1260 1110 695 5120 1400 1560 1470 1290 760 5130 1370 1490 1370 1280 680 5140 1360 1450 1340 1265 620 5150 1330 1420 1330 1290 555 5160 1310 1410 1320 1250 490 52100 1340 1440 1320 1270 485 6150 1380 1450 1370 1270 545 8620 1350 1525 1415 1220 745 8630 1355 1475 1370 1220 680 8640 1350 1435 1340 1200 610 8645 1350 1430 1310 1230 575 8720 1350 1530 1420 1220 740 9260 1370 1500 1380 1315 550 9310 1315 1490 1305 830 — 9317 1300 1455 1290 800 — 9442 1350 1435 1280 1190 —

Formula for calculating approximate Ms point based on chemical composition: Ms (˚F) = 930 – (600 x %C) – (60 x %Mn) – (50 x %Cr) – (30 x %Ni) – (20 x %Si) – (20 x %Mo) – (20 x %W)

The following symbols for critical temperatures are used for the heat treatment of steel: Ac1: The temperature at which austenite begins to form during heating.Ac3: The temperature at which transformation of ferrite to austenite is completed during heating. Ar3: The temperature at which austenite begins to transform to ferrite (or to ferrite plus cementite) during cooling. Ar1: The temperature at which transformation of austenite to ferrite (or to ferrite plus cementite) is completed during cooling. Ms: The temperature at which the transformation of austenite to martensite starts during cooling. Mf: The temperature at which transformation of austenite to martensite finishes during cooling.

On Heating On Cooling On AISI 50˚F per Hour 50˚F per Hour Quenching Grade Ac1 Ac3 Ar3 Ar1 Ms (˚F) (˚F) (˚F) (˚F) (˚F)

On Heating On Cooling On AISI 50˚F per Hour 50˚F per Hour Quenching Grade Ac1 Ac3 Ar3 Ar1 Ms (˚F) (˚F) (˚F) (˚F) (˚F)

Approximate Critical Temperatures Of Carbon And Alloy Steels(Sources: “Practical Data For Metallurgists,” The Timken Co., Canton, Ohio, 1977; “AISI/SAE Bar Data Handbook,”

Inland Steel Bar Co., East Chicago, Ind., Date Unknown).



Equilibrium Curves For Furnace Gases On Iron, Carbon & Steels(Source: Surface Combustion Inc., Maumee, Ohio)

Effect of Gas Constituents on Metals

Metal O2 CO2 CO H2 H2O CH4 N2

Iron (Fe) Oxidize Oxidize Carb. — Oxidize Carb. —

Iron Carbide (Fe3C)

Oxidize & Decarb. Oxidize & Decarb. — Decarb. Oxidize & Decarb. — —

Iron Oxide (FeO) — — Reduce Oxide Reduce Oxide — Reduce Oxide —

Copper (Cu) Oxidize — — — — — —

If the combustion system is lacking the design air pressure, check to make sure the blower is in its proper rotation. You would be stunned at the number of new installations or

retrofi t systems that stumble during startup because of this simple wiring mistake. A c ombustion air blower is designed to spin toward the outlet in a laminar fashion. If the blower is rotating at a r ight angle to the outlet (the wrong way), bet-ter than a third of your capacity can be lost. It also can create problems for the motor.

Any fi lter blockage will result in serious problems. As the system bogs down under a clogged fi lter, your process may not get the required input. Clogged fi lters put un-

due strain on the combustion air blowers over time, so your electrical and motor maintenance costs may escalate. And, worst of all, the burners may go fuel rich. This wastes fuel and can create carbon, which at its best is an insulator and a mess. At its worst, it is a fi re hazard.

Not Enough Pressure? Check Your Blower Rotation

Keep Filters CleanTIP # TIP #

1 11


IndustrialGases

Pressure RelationshipsReprinted with permission from “Guide to Burners/Combustion Data” presented by Hauck Manufacturing

Conversion Table of Pressure Equivalents

Lbs. per sq. In.

Oz. per sq. in. Ft. H2O

Inches H20

mm H20 mbar kPa Inches Hg.

kg per cm2

1.000 16.00 2.309 27.710 703.834 68.970 6.897 2.040 .070

.063 1.000 .144 1.732 43.993 4.345 .431 .127 .004

.433 6.928 1.000 12.000 304.800 29.864 2.985 .888 .030

.036 .572 .083 1.000 25.400 2.464 .2464 .074 .003

.001 .023 .003 .039 1.000 .098 .010 .003 .0001

.015 .232 .033 .402 10.208 1.000 .100 .030 .001

.145 2.320 .334 4.020 102.00 10.183 1.000 .295 .010

.491 7.858 1.134 13.610 345.694 33.864 3.386 1.000 .035

14.220 227.600 32.842 394.100 10010.140 980.700 98.070 28.960 1.000

Q2=Q

1∆ p

2∆ p

1

Q2=Q

1Sg

1

Sg2

Q2=Q

1F

1+460

F2+460

Q2=Q

1p

2+14.7

p1+14.7

Q2=Q

1A2

A1

∆ p2=∆ p

1

Q2

2

Q1

∆ p2=∆ p

1

A1

2

A2

∆ p2=∆ p

1

Sg2

Sg1

∆ p2=∆ p

1

F2+460

F1+460

∆ p2=∆ p

1

p1+14.7

p2+14.7

Where:

∆ p=pressure drop p=pressure in PSIQ=STP flow F=degrees ˚FA=area Sg=specific gravity

Various relationships for fl ow and pressure

Atmosphere Classifi cations

Atmospheres generated for heat treating processes are classifi ed into six major categories, according to

the American Gas Association:

Class 100/Exothermic Base - composed of the products of an air-fuel gas mixture;

Class 200/Prepared Nitrogen Base - a Class 100 atmosphere with various amounts of CO2 and

H2O removed;

Class 300/Endothermic Base - produced by partial reaction of a gas-fuel mixture in an externally

heated catalyst fi lled retort;

Class 400/Charcoal Base - atmosphere produced by passing air through incandescent charcoal in an

externally heated vertical retort;

Class 500/Exothermic-Endothermic Base - produced by the complete combustion of an air-fuel

gas mixture with most water vapor removed and reforming most of the CO2 to CO.

Class 600/Ammonia Base - Any atmosphere produced with ammonia (NH3) as the primary

constituent.

Generation, Application and Control of Furnace Atmospheres

Measure the content of oxygen left over from the chemical process of combustion with

an oxygen analyzer. Costs for simple portable units range anywhere from $400 to $3000, but the devices should pay for themselves within a year. In oven or heater operations, have your combustion technician show you where to spot check the fl ue products so that you can detect changes. If changes become dramatic, have your technician tune the burners. Remem-ber, in some operations O

2 levels may

be high due to a ir entrainment from other sources, but the O

2 can still be

measured and change may be recog-nizable. Check monthly.

Use an Oxygen AnalyzerTIP #

15


IndustrialGases

Compositions & Characteristics for Various Classes of Prepared AtmospheresClass method of preparation

Gas content, % Dew Gas N2 CO CO2 H2 CH4 Point °F Consump.[1] Safety questions

Class 100 Exothermic Base

101 Lean Exothermic Mixture 86.8 1.5 10.5 1.2 - [2] 120 Non-Combustible: Toxic

102 Rich Exothermic Mixture 71.5 10.5 5.0 12.5 0.5 [2] 155 Combustible: Toxic

103 Class 101 Prepared Directly in Furnace - - - - - - - -

104 Class 102 Prepared Directly in Furnace - - - - - - - -

105 Class 101 Followed By Passage Through Incandescent Charcoal 77.8 20.1 - 2.1 - - - Combustible: Toxic

106 Class 102 Followed By Passage Through Incandescent Charcoal 67.3 19.3 - 12.9 0.5 - - Combustible: Toxic

Class 200 Prepared N2 Base

201 Lean Prepared Nitrogen 97.1 1.7 - 1.2 - -40 135 Non-Combustible: Inert: Toxic

202 Rich Prepared Nitrogen 75.3 11.0 - 13.2 0.5 -40 180 Combustible: Toxic

207 Class 201 Plus Raw Hydrocarbon - - - - - - - -


223 Class 201 Plus Steam With Catalyst to 96.9 0.05 0.05 3.0 - -40 - Combustible: Toxic

Convert Carbon Monoxide (CO)

224 Class 202 Plus Steam With Catalyst to Convert Carbon Monoxide (CO) 89.9 0.05 0.05 10.0 - -40 - Combustible: Toxic

Class 300 Endothermic Base

301 Partially Reacted Followed By Quick Cooling to Eliminate Breakdown of 2CO=C+CO2

45.1 19.6 0.4 34.6 0.3 +50 190[3] Combustible: Toxic

302 Completed Reacted and Quickly Cooled 39.8 20.7 - 38.7 0.8 0 to –5 200[3] Combustible: Toxic

323 Gas-Air-Steam Mixture With Catalyst to Convert CH4

5.0 21.4 8.0 65.6 5.0 [2] 260 Combustible: Toxic

325 Gas-Air-Steam Mixture With Catalyst to Convert CO Rest 0.05 to 1.0 0.05 to 2.0 50.0 to 99.6 0.0 to 0.4 - - -

Class 400 Charcoal Base

402 Charcoal Base 64.1 34.7 - 1.2 - -20 12.5 lbs Charcoal Combustible: Toxic


Class 500 Exothermic

501 Lean Exothermic-Endothermic 63.0 17.0 - 20.0 - -70 120 Combustible: Toxic

Class 600 Ammonia Base

600 Ammonia-Raw

601 Dissociated Ammonia 25.0 - - 75.0 - -60 23.5 lbs ammonia Combustible

621Lean Combusted Ammonia. Refrigeration or Adsorbent Tower Dehydration Depending on Desired Dew Point.

99.0 - - 1.0 - [2] 13.7 lbs ammonia Non-Combustible: ammonia Relatively Inert

622Rich Combusted Ammonia. Refrigeration or Adsorbent Tower Dehydration Depending on Desired Dew Point.

80.0 - - 20.0 - [2] 14.9 lbs ammonia Combustible

[1] Gas Consumption in cu. ft. per 1000 cu. ft. of atmosphere based on 1000 Btu natural gas. For other gases, multiply by 2.0 f or high H2, high CO and artificial gas: 0.4 for propane and 0.3 for butane.[2] Dew point corresponds to room temperature using tap water cooling. May be reduced to 40°F by refrigeration of –50 by adsor bent towers.[3] Plus 250 cu. ft. per 1000 cu. ft. for heating gas.Reference: American Gas Association, Report #104, I. Jenkins, “Controlled Atmospheres for the Heat T reatment of Metals,” Chapman & Hall 1946.


Fuels and Flue Data

90 290 490 690 890 1090 1290 1490 1690

Flue gas temperature °C

Available heat for natural gas

Flue gas temperature °F

% A

vaila

ble

heat

200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 3200

For various percent xsa100

90

80

70

60

50

40

30

20

10

0

400% 200%

300%

50%

100%25%

0%

10%

%, x

sa

Hot mix temperature, °F

Hot mix temperature, °C

Hot mix temperature vs. % excess air for natural gas

3000

2500

2000

1500

1000

500

0 200 1000 1800 2600 3400

90 490 890 1290 1690

Fuels and Flue DataReprinted with permission from “Guide to Burners/Combustion Data” presented by Hauck Manufacturing

Typical Fuels Data for fuels at 60°F and 29.9” Hg

Fuel Type Specifi c Gravity(air=1.0 or *water=1.0

Gross Btu per Ft3

Gross Btu per gal.

Stoichiometric ratio Neutral air fuel

(Ft3 air/unit fuel)

Natural 0.6 1035 – 10.0

Propane 1.52 2520 – 23.8

Butane 2.01 3260 – 30.0

Coke Oven 0.40 550 – 5.54

Hydrogen 0.069 326 – 2.38

Liquid propane 0.505* – 91,000 8.51

No. 2 fuel oil 0.876* – 138,000 1365

No. 6 fuel oil 1.04 approx.* – 150,000 1485

If controls have moved or another phenomenon has caused the burn-er to l ean out, it could be costing

you a f ortune. Most burners are de-signed to b urn with a s mall percent-age of excess air (less than 15%). Some exceptions include air heating equip-ment and low temperature operations where the excess air is used to control the temperature of the fl ame. If you have a burner designed to run at 10% excess air and the burner drifts into the range of 50% (that is a difference of 5% O2 or 7.5% O2 in the products of combustion), the difference in a 1000F (538C) oven operation is 7% loss of effi ciency. If you had a one mil-lion BTU burner, and gas costs of $5 per 1,000 cfm, keeping one burner in tune would save approximately $2,600 per year.

TIP #

14Eliminate Excess Air

ADVERTISERWEBSITE

INDEX

☛

Page COMPANY NAME PHONE WEBSITE ADDRESS 7 BeaverMatic, Inc. 815-963-0005 www.beavermatic.com 17 Custom Electric Manufacturing Co. 248-305-7700 www.custom-electric.com 2 Eclipse Combustion 800-800-3248 www.eclipsenet.com 19 Flinn & Dreffein Engineering Co. 847-272-6370 www.fl inndreffein.com 27 Hauck Manufacturing 717-272-3051 www.hauckburner.com 15 INEX Incorporated 716-537-2270 www.INEXinc.net 4 Maxon Corp. 765-284-3304 www.maxoncorp.com 28 Selas Heat Technology Co., LLC 800-523-6500 www.selas.com 3 Siemens Building Technologies, Inc. 847-215-1050 www.siemenscombustioncontrols.com 25 WS Thermal Process Technology Inc. 440-365-8029 www.fl ox.com


Fuels and Flue Data

Flue Gas Component DataReprinted with permission from Hauck Manufacturing

Emissions Conversion ChartReprinted with permission from Hauck Manufacturing

1

0.9

0.8

0.7

.06

.05

0.4

0.3

0.2

0.1

0 0 100 200 300 400 500 600

0 2 4 6 8 10 12 14

2.62.42.2

21.81.61.41.2

10.8

(Birmingham natural gas)(3% O2 base)

% Oxygen (O2) dry

PPM correction factors

Natural gas fi red systems

PPM @ 3% 02 dry fl ue products

Mul

tiply

PPM

by

this

fact

or

Poun

ds p

er m

illio

n Bt

u

Nox as NO2

CO

Combustibles as CH4

This chart is intended as a quick reference sheet for emissions conversion. This cart is valid for combustion products of natural gas similar to Birmingham (1004 Btu/Hr, s.g. 0.6, 90% methane, and 5% nitrogen). A typical example is as follows:Sample contains 7.5% O2, 45 ppm NOx, 100 ppm CO, and .09% combustibles:1. Correct all readings to 3% O2 reference

by multiplying emissions readings by the correction factor on chart insert (O2 of 7.5% = 1.3)

2. NOx: 45 x 1.3 = 58.5 ppm, CO: 100 X 1.3 = 130 ppm, combustibles: 0.9% x 10,000 (convert to ppm) x 1.3 = 1170 ppm combustibles

3. Find values on chart. NOx of 58.5 ppm - .308 lbs/millon Btu, CO of 130 ppm = .09 lbs/million Btu, combustibles of 1170 ppm = .48 lbs/million Btu.

Flue Gas Component Data at 60°F and 29.9” Hg

Flue gascomponents Formula Molecular

weight

Specifi c gravity

(air=1.0)

Density (Lb/Ft3)

Ft3 per lb.

Oxygen 02 32.00 1.1053 0.0844 11.819

Carbon dioxide CO2 44.01 1.5282 0.1161 8.548

Carbon monoxide CO 28.01 0.9672 0.0739 13.506

Nitric oxide NO 30.00 1.0380 0.0792 12.626

Nitrogen dioxide NO2 46.00 1.5917 0.1214 8.237

Nitrogen N2 28.02 0.9718 0.0739 13.443

Air – 28.90 1.0000 0.0763 13.063

Sulfur dioxide SO2 64.06 2.2640 0.1690 2.264

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Contact: Becky McClelland at 412-306-4355 or

[email protected]

The International Journal of Thermal Processing JANUARY 2015

INSIDE

25 Keeping Hot with PIES32 Combustion Safeguards35 Rockwell Hardness Evolution38 Technology SpotlightsA Publication • Vol. LXXXIII • No. 1

Heat Treating’sA Look at the North American Heat-Treating World

28

The International Journal of Thermal Processing FEBRUARY 2015

INSIDE

6 IH Connect34 Combustion Resources44 Firebricks Save Energy48 Cutting-Edge StainlessA Publication • Vol. LXXXIII • No. 2www.industrialheating.com

The Other White Metal 38

The International Journal of Thermal Processing MARCH 2015

INSIDE

30 CQI-9 for Induction 35 Heat-Treatment Opportunities 42 LPC of Pyrowear® Alloy 53 58 Commercial Heat Treaters Directory

A Publication • Vol. LXXXIII • No. 3 • www.industrialheating.com

Muffles &Retorts,

Calciners 52

The International Journal of Thermal Processing APRIL 2015

INSIDE

31 Money-Saving Burner38 Fastener Thermal Processing44 Ceramic-Fiber Modules47 Aftermarket DirectoryA Publication • Vol. LXXXIII • No. 4 www.industrialheating.com

Thermal CaptureTechnology 35

Page COMPANY NAME PHONE WEBSITE ADDRESS 7 BeaverMatic, Inc. 815-963-0005 www.beavermatic.com 17 Custom Electric Manufacturing Co. 248-305-7700 www.custom-electric.com 2 Eclipse Combustion 800-800-3248 www.eclipsenet.com 19 Flinn & Dreffein Engineering Co. 847-272-6370 www.fl inndreffein.com 27 Hauck Manufacturing 717-272-3051 www.hauckburner.com 15 INEX Incorporated 716-537-2270 www.INEXinc.net 4 Maxon Corp. 765-284-3304 www.maxoncorp.com 28 Selas Heat Technology Co., LLC 800-523-6500 www.selas.com 3 Siemens Building Technologies, Inc. 847-215-1050 www.siemenscombustioncontrols.com 25 WS Thermal Process Technology Inc. 440-365-8029 www.fl ox.com


Fuels and Flue Data

Heat recovery can be divided into three main categories:• Direct Recovery occurs when waste

gas temperature is lowered through modifi cations of the heating system itself. Lengthening a pu sher-type shell reheat furnace is an example of direct recovery.

• Indirect Recovery occurs when the waste gas is used to preheat anything that enters the heating system, which could be combustion air, fuel or the material to be preheated in the heating system.

• Secondary Recovery uses waste gas to preheat an external medium. Genera-tion of steam is an example.

Direct Recovery is dealt with by the de-signer of the heating system. The most economical and effi cient method of Indirect Recovery is preheating combustion air. The table above specifi es values of fuel savings for various waste gases and air pre-heat temperatures. The higher the waste gas and air preheat temperature, the great-er the percentage of fuel is saved.

As opposed to Indirect Heat Recovery, Secondary Recovery is used to preheat any medium that does not directly enter the heating system. Applications for Second-ary Heat Recovery include steam genera-tion, preheating thermal fl uids for process heating and space heating utilizing hot water or air.

Source: Combustion Technology Manual, 5th Ed., Industrial Heating Equipment Associa-tion, 1994.

Heat Recovery and Fuel SavingsPercent fuel savings for various combustion air preheat temperatures

Preheat temperature, °F

Furnace outlettemperature, °F 400 500 600 700 800 900 1000 1100 1200 1300 1400

2600 22 26 39 34 37 40 43 46 48 50 52

2500 20 24 28 32 35 38 41 43 45 48 50

2400 18 22 26 30 33 36 38 41 43 45 47

2300 17 21 24 28 31 34 36 49 31 43 45

2200 16 20 23 26 29 32 34 37 39 41 43

2100 15 18 22 25 27 30 33 35 38 39 41

2000 14 17 20 23 26 29 31 33 36 38 40

1900 13 16 19 22 25 27 30 32 34 36 38

1800 13 16 19 21 24 26 29 31 33 35 37

1700 12 15 18 20 23 25 27 30 32 33 35

1600 11 14 17 19 22 24 26 28 30 32 34

1500 11 14 16 19 21 23 25 27 29 31 33

1400 10 13 16 18 20 22 25 27 28 30 —

Fuel is natural gas at 10% excess air.

If you notice a variation in fl ame color, something has changed and not for the better. Bright,

luminescent fl ames generally indicate a g as-rich condition. The exception would be radiant

tube or incinerator burners, which are designed to be luminescent. A bright, white or wispy

blue fl ame often indicates lean burn or excess air. The exception is air heat-type burners that,

by design, burn with a lean fl ame. And, of course, if you see soot or carbon on the fl oor, bad

things are happening in the combustion process. With the exception of one or two industrial

processes, a sooty fl ame is not desirable. If a sooty fl ame occurs, have a technician review the

burner settings as soon as possible. Soot is a solid form of your fuel dollars.

TIP #

19Check Flame Color


Burners

Self-Regenerative Burner for Single-Ended, P and Double-P Radiant TubesDr. Joachim G. Wuenning - WS Thermal Process Technology Inc., Elyria, Ohio

Gas-fi red radiant tubes are widely used to heat industrial furnaces. Energy ef-fi ciency has become a top priority for many companies in the heat-treating busi-ness. This paper will discuss the available options and will present a new type of regenerative burner for radiant-tube heating.

egenerative air preheating is accepted as the most effec-tive way to increase energy effi ciency for high-tempera-ture process heating, but it

was seen as too complex and expensive for heating small and medium size heat-treating furnaces.

Self-Regenerative BurnerSelf-regenerative burners combine a r e-generative system and the burner into one compact unit. All switching valves and controls can be integrated into the burner housing. Figure 5 shows how the exhaust and air fl ow are directed through the burner. The heat of the exhaust is stored in ceramic honeycomb regenerators and transferred to the combustion air when the fl ow direction switches. Cycle times on the order of 10 seconds provide even conditions. The fuel supply is constant and does not need to be switched unlike

in regenerative burner-pair designs. At high furnace temperatures, the FLOX®

– fl ameless oxidation combustion mode – ensures low NOx emissions in spite of very high combustion-air preheat temperatures. Figure 6 s hows a s elf-regenerative burner that could be used for direct fi ring and for heating of recirculating radiant tubes. The self-regenerative burner is used in combi-nation with a pulse-fi ring system, meaning the burner is on/off controlled. A l ocal burner-control unit handles all the logic for regenerative switching, fl ame safety, ignition and valve operation. That makes the installation, start-up and maintenance as easy as with self-recuperative burners. The tube temperature uniformity is excel-lent due to alternating fl ow directions and the internal recirculation, and NOx emis-sions are low due to fl ameless oxidation.

ConclusionsThere are many options of radiant-tube

systems on the market. To fi ght the chal-lenges of rising energy costs and environ-mental regulations, a c lose cooperation of the end user, the furnace builder and the burner manufacturer is necessary to choose the best possible confi guration with respect to:• Radiant-tube performance• Energy effi ciency• Low emissions• Low maintenanceAnd of course investment-cost optimization is always an important consideration. IH

FLOX® and REGEMAT® are trademarks of WS Inc.

For more information: Dr. Joachim G. Wuen-ning is the president of WS Thermal Process Technology, Inc., 719 Sugar Ln., Elyria, OH 44035 ; tel : 440-365-8029 ; fax : 440-365-9452 ; e-mail : WSInc@fl ox.com; web : www.fl ox.com

This article originally appeared in June 2007. Read it in its entirety at www.industrialheating.com/toolkit/wsthermal

R

Fig. 6. Self-regenerative burner REGEMAT®

Pneumatic switching valves

Orifi ces

Exhaust

Regenerators

Combustion air

FLOX®

Flame

Fuel Flame air

Furnace wall

a)

b)

Fig. 5. Self-regenerative burner principle


Burners

andfi ll gas (LFG) is created as solid waste decomposes in a landfi ll. This gas consists of about 50% methane, the

primary component of natural gas, about 50% carbon dioxide and a small amount of non-methane organic compounds.

Renewable Fuel Opportunities Instead of allowing LFG to escape into the air, it can be captured, converted and used as an energy source. The alternative use of LFG helps to reduce odors and other haz-ards associated with LFG emissions, and it helps prevent methane from migrating into the atmosphere and contributing to local smog and global climate change. Landfi ll gas is extracted from landfi lls us-ing a series of wells and a blower/fl are (or vacuum) system. This system directs the collected gas to a c entral point where it can be processed and treated, depending upon the ultimate use for the gas. From this point, the gas can be simply fl ared or used to generate electricity, replace fossil fuels in industrial and manufacturing op-erations, fuel greenhouse operations or be upgraded to pipeline-quality gas. Pressurized methane gas can be piped underground and burned as a r enewable fuel for manufacturing facilities at a lower cost than other fuels such as natural gas. In North America, and the United States specifi cally, landfi ll property that is in close proximity to manufacturing facilities can be a ready source of energy. Given that all landfi lls generate meth-ane, the benefi cial use of LFG makes eco-

nomic and social sense. Because methane is both potent and short-lived, reducing methane emissions from landfi lls is one of the best ways to achieve a near-term ben-efi cial impact in mitigating global climate change. The greenhouse gas reduction benefi ts of using 1,000,000 btu/hour of LFG in a typical production facility are the equivalent of planting almost 1,200 acres of forest per year or removing the annual carbon dioxide emissions from more than 800 cars.1

Recognize Alternative Fuel Incon-sistenciesGiven its nature of formation and the variability between landfi lls, it is pru-dent to have an independent labora-tory analyze the constituents of the gas as part of the initial project development. The lab analysis will provide an insight into the fuel characteristics and very often determine the scope and details of project requirements. In many in-stances, LFG contains one or more species of siloxanes. S iloxanes are non-toxic organosilicates that are used in many consumer and industrial prod-ucts to enhance certain product charac-teristics. Organosilicates volatilize and are carried with the landfi ll gas as part of the organic decomposition process. As the LFG is combusted, the organosilicate reduces to silicon dioxide (SiO2), often creating deposits on the combustion and heat-transfer equipment. Siloxane fi ltra-tion technology exists that will remove

various siloxane species to below detec-tion limits.

Identify Potential Processes in Your FacilityThe most likely candidates for renewable fuel usage are those processes that have fairly consistent and continuous ther-mal-loading/fuel-usage profi les. Processes whose fuel consumption fl uctuates due to changes in production, weather or other process characteristics will place a d iffi -cult demand on the supply of LFG from the landfi ll. LFG is typically produced on a 24/7 basis. Any fuel not used is generally

fl ared at the landfi ll.

Converting Your Process To Alternative Renewable FuelsGordon Harbison, Dürr Systems, Inc., Plymouth, Mich., and George Fritts, Eclipse, Inc., Rockford, Ill.

Renewable fuels have long had a “green” characteristic associated with the environmental beneÿ ts of their use. With the rising cost of fossil fuel, renewable fuels now show a green economic beneÿ t by lowering operating costs in industrial facilities with thermal processes. This article addresses and highlights the beneÿ cial use of alternative fuels and the equipment modiÿ cations often required for renewable fuel use.

andfi ll gas (LFG) is created as solid waste decomposes in a landfi ll. This gas consists of about 50% methane, the

primary component of natural gas, about L

Fig. 1. LFG-capable furnace burner


Economic Benefi tsRenewable fuels such as landfi ll gas are typically procured from landfi ll operators on a l ong-term contractual basis. Many landfi ll operators use their gas to generate electricity on-site to sell green power to the local utilities, requiring a c apital invest-ment on t heir part. Selling the available

landfi ll gas as a direct fuel replacement to natural gas requires the marriage of process opportunity and available fuel. This sort of partnership benefi ts both the process facil-ity and the landfi ll operator on a long-term basis. Typically LFG supply contracts have a tiered fi xed-price structure that enable many renewable fuel-conversion projects to be implemented with attractive, short investment payback periods of generally less than three years. Because of the fi xed price advantage of LFG, the rising cost of natural gas only increases the relative sav-ings for the plant and shortens the payback period. An investigation of what sort of re-newable fuel is available near your facility is an excellent starting point. (Do not be daunted by distances. BMW (see sidebar)

had a 9 .5-mile pipeline constructed that crosses a r iver, two creeks, an interstate highway and their test track in order to de-liver the available LFG to the Spartanburg facility.) Then have a detailed analysis of your process and production requirements done in order to determine the maximum benefi cial use of alternative fuels and to secure the operating cost benefi ts for your facility. As companies begin to investi-gate, characterize and analyze their energy consumption, they will discover unknown profi t possibilities. Improvements in energy usage and the associated environmental impacts are within reach today and can be enacted without sacrifi cing companies’ economic well-being. IH

1http://www.epa.gov/lmop/res/lfge_bene fi tscalc_022806.xls: The US EPA calculates the Total Equivalent Emissions Reduction based on the reduction of methane emitted directly from the landfi ll plus the offset of carbon di-oxide from avoiding the use of fossil fuels.

For more information: Contact: Gordon M. Harbison, C.E.M., Manager, Service Solutions, Dürr Systems, Inc., 40600 Plymouth Road, Plymouth, MI 4 8170; e-mail: gordon.harbi-son @durrusa.com; or George Fritts, Product Manager, Low Temperature Products, Eclipse, Inc., 1665 Elmwood Road, Rockford, IL 61103; e-mail: [email protected]

This article originally appeared in October 2006. Read it in its entirety at www.industrialheating.com/toolkit/durr

LFG and Natural Gas Comparison

Fuel Gas Characteristic LFGNatural

Gas

Gross heating value (Btu / cubic foot)

300 - 500

950 -1100

Specifi c Gravity 1.0 - 1.2 0.6 - 0.7

Methane, CH4 content (%) 30 - 50 85 - 95

Carbon Dioxide, C02 content (%)

50 - 70 0 - 5

Four turbines at the Spartanburg, S.C., facility of BMW Manufacturing Co. LLC have been using “Green Energy” since January 2003 when BMW executed a l ong-term contract procuring Landfi ll Methane Gas (LFG) at a fi xed cost from the Palmetto Landfi ll almost 10 miles away from the plant. The landfi ll, however, was capable of supplying BMW with more LFG than was being used to run the innovative co-generation system that produces on-site power and generates hot and cold water. In order to identify the potential for using the additional LFG as thermal energy in the paint-shop process equipment and eliminate the requirement for natural gas as a fuel, BMW worked in partnership with Dürr Systems, Inc., the supplier of the original process equipment. Dürr is also an Industry Partner in the Landfi ll Methane Outreach Program (LMOP) and experienced in applying renewable fuels in process equipment. The primary evaluation criteria for process equipment use was a consistent, year-round, thermal load/fuel usage and no potential for detrimental impact on the equipment or the painting process as a result of LFG combustion by-products. Process equipment and production uptime requirements also had to be considered. During the summer of 2006, BMW Manufacturing became the fi rst automotive company to use an alternative, renewable fuel to fuel its painting process equipment. All of the pro-cess equipment targeted for this landmark project had existing burners and gas trains that required replacement or modifi cation in order for the burners to run on LFG. Twenty-three paint-shop process burners and safety valve trains were replaced in this project because of the lower BTU content of the LFG and the increased volumetric-fl ow requirements. The Eclipse RatoAir burners installed by Dürr during this project did not change the ther-

mal energy requirements of the pro-cess equipment. This additional use of methane in the BMW paint shop did not impact the production of electric-ity on site and has greatly reduced the paint shop’s reliance on natural gas, providing fi nancial benefi ts to BMW and signifi cant environmental benefi ts to the surrounding community. Long dedicated to conservation, BMW’s commitment to environmental re-sponsibility is the driving force behind the development of this sort of envi-ronmentally friendly innovation.

World’s First Green Automotive Paint Shop

and signifi cant environmental benefi ts to the surrounding community. Long

the development of this sort of envi-

Just like the air and gas source at the inlet, exhaust systems should be balanced and provide for free

fl ow of the fl ue products. It is particu-larly common for building pressure in Northern climes to affect combus-tion system performance during cool weather. Makeup air systems and building heating systems can pressur-ize or create a negative pressure dur-ing weather fl uctuations, and burners can become unbalanced if the exhaust system cannot accommodate the change. Notice a c hange in furnace performance? Notice a change in the weather? They might be related.

Breathe In, Breathe OutTIP #

3


Analysis & Control

Optimizing Combustion ControlsDan Curry – Eclipse, Inc., Rockford, Ill.

From the narrowest to the broadest deÿ nition of combustion control, the goal is to achieve the best production results with a system that is safe and reliable.

hat do y ou think of when you hear the ter-minology “combustion controls?” Maybe you

would answer with any one or a combina-tion of the following:• Flame-safeguard control – making sure

there is fl ame present while gas is fl ow-ing to the burner

• Temperature control – adjusting the fi r-ing rate to maintain the process heat

• Air-fuel-ratio control – maintaining proper burner effi ciency

• Process control – a djusting multiple system components such as the burner fi ring rate, furnace pressure, circulation and exhaust fan rates, and product feed rates to achieve the best production results

All of these are important to consider for potential energy savings and reduced emissions. Collectively, they direct us to safely control combustion for effective and effi cient heat generation and transfer, to maximize heat containment and to take advantage of heat recapture.

Before Considering a New Combustion Controller Manufacturing owners and managers are continually looking for ways to reduce production costs and increase produc-tion rates. With the great technological advances in electronic controllers, the temptation may be to look to the mysteri-ous and magical “black box” as a solution. Sometimes a s alesman under pressure to make his quota may reinforce the idea of the fancy electronic control system as a panacea. Unfortunately, the most sophis-ticated controllers will not fi x a poorly de-signed thermal process.

For example, an expensive air-fuel-ratio controller may provide some energy savings in the range of 2-10% over a conventional ratio-control system. The investment could be very large, however, making the pay-back excruciatingly long. Other actions to get even greater energy savings of 10-50% include:• Properly selecting heating equipment

for the application• Maintaining and fi xing worn-out ther-

mal-process equipment• Replacing with newer burner designs

having higher effi ciencies and reduced emissions

We should investigate these fi rst before considering retrofi tting with an expensive control system.

Replace Old Outdated EquipmentIn many thermal-processing facilities, it is not uncommon to see combustion equip-ment that is over 15 years old. Newer burn-ers offer substantial advances in nozzle mixing that can improve heat transfer, and they can reduce emissions that were not regulated or even considered years ago. Higher burner turndown (maximum-

to-minimum fi ring ratio) allows tighter temperature-control regulation. Low turn-down systems often must shut off to pre-vent over-temperature conditions when the process load is at minimum. During the off time, the process may cool too much, requiring excess energy to get back to the original temperature.

Mass-Flow Ratio Control Most of the previous methods need well-regulated air and fuel pressures into the control valves. Also, variations of the chamber back pressure may cause shifts to the ratio. In cases where these condi-tions are not well regulated, then you must add fl ow monitoring to the control scheme (Fig. 9). The fl ow sensors provide feedback to the controller that will then make corrections in actuator positions to continuously maintain the correct ratio. Advantages are its precision overall fi ring rates, and it is a true fl ow-control method. Disadvantages are that electronic skills are needed for commissioning, a s ensor failure could lead to an unsafe condition, and it has a higher cost. The controller could be a dedicated unit

Type Turndown V/M Response Cost

Diff. pressure 3/10:1 V Fast $ / $$

Displacement 100:1 V Slow $$

Turbine 10:1 V Medium $

Vortex 30:1 V Medium $

Thermal 100:1 M Fast $

Coriolis 50/200:1 M Fast $$

Ultrasonic 50/3000:1 V Fast $$$

Laser 1000:1 V Fast $$$

V = velocity: need T&P compensation for true mass fl owM = true mass fl ow sensor

Fig. 1. Summary of sensors

hat do you think of when you hear the ter-minology “combustion controls?” Maybe you W


Analysis & Control

specifi cally designed for the application or a generic programmable multi-loop unit. It should use cross-limiting for its control scheme or algorithm. This helps to prevent an unsafe burner fi ring condition by always keeping the fuel set point limited to the lowest value of either fi ring-rate demand or actual airfl ow. Likewise, the air set point is set to the highest value of either the de-mand or fuel fl ow. Therefore, cross-limiting prevents a fuel-rich ratio on rapid changes in the fi ring-rate demand signal. A key factor in successful mass-fl ow implementation is the choice of the fl ow sensors. As with any sensor, it must be selected to match the process conditions. It must stand up to the ambient condi-tions and the pressure, temperatures and contaminants of the process gases. When comparing sensor types, the primary characteristics for good mass-fl ow ratio control are: • Turndown – The sensor must be able to

handle the range of the burner. Some sensors will drop off to the minimum output signal when the fl ow drops below a certain range. In ratio control, if this happens on the air sensor before the gas sensor, it could lead to an unsafe gas-rich condition.

• Repeatability – A lthough accuracy is always good, it is not as important as repeatability in ratio control. During commissioning, any accuracy problems are adjusted when the ratio is pro-grammed at each fi ring position.

• Response time – If the sensor response

time is longer than the control actuators stroke, the system will be unstable and it will be diffi cult to tune the controller.

• Drift – A n electronic system is not maintenance free. The drift rating will determine how often the system will re-quire calibration.

Some sensors base their measurements on gas velocity or volume, so the mass fl ow must be calculated from additional inputs of temperature and pressure. These include the differential pressure, positive displacement, turbine, vortex shedding, ultrasonic and laser types. However, ther-mal dispersion and coriolis sensors base their measurements on true mass fl ow. A brief summary of sensors is shown in Figure 10. The column V/M shows V if the sensor is velocity or volume-based and shows M for a true mass-fl ow sensor. In some types, the turndown shows a range to cover the variety of implementations from manufacturers. For example, an orifi ce meter with a s imple differential-pressure transmitter may only provide a 3 :1 turn-down, but when the orifi ce is supplied with a matched “smart” microprocessor system, the turndown can increase to 10:1.

SummaryIn the broadest sense, optimizing combus-tion can refer to controlling the complete thermal-process system. Narrowing down, it can refer to the design of the nozzle in a burner. From the narrowest to the broad-est defi nition, our goal is to achieve the

best production results with a system that is safe and reliable. The market directs us to improve effi ciency for energy savings and to reduce emissions. It is accomplished best when we evaluate and prioritize the most benefi cial actions, whether changes in heating equipment, implementing a maintenance program or adopting a n ew controller. IH

For more information: Dan Curry is an elec-tronic products engineer for Eclipse, Inc., 1665 Elmwood Rd., Rockford, Ill. 61103; tel: 815-877-3031; fax: 815-637-7049; email: [email protected]; web: www.eclipsenet.com

This article originally appeared in October 2007. Read it in its entirety at www.industrialheating.com/toolkit/eclipse

Fuel savings, %

Furnace exhaust Temperature, °F

Preheated air temperature, °F 600 800 1000 1200 1400 1600

2400 26 32 38 43 47 51

2200 23 29 34 39 43 47

2000 20 26 31 35 39 43

1800 18 24 28 33 37 40

1600 17 22 26 30 34

1400 15 20 24 28

1200 14 19 23

1000 13 18

Fig. 2. Fuel savings using preheated air Fig. 3. Damaged furnace door – excessive rediation leaks

Combustion experts speak in terms of pressures, velocities and fl ows because these are

critical to b urner operation. By un-derstanding and knowing burner pressures and fl ows, you can detect changes in performance early and help troubleshoot any problems.

A manometer is an inexpensive de-vice for measuring air pressure. If you do not have one, get one. Have your burner technician show you where to check the pressure inputs on your burner, then check them monthly. If you notice a change in pressure, alert your combustion technician to g et the burner back in tune.

Check Your PressureTIP #

12


Analysis & Control

ROI Analysis of Combustion Control for Gas-Fired Heat-Treating FurnacesE.S. Boltz, Y.H. Boltz, B. Knight and P.J. Barker – Marathon Sensors Inc., a member of United Process Controls

Over the last several years, operational costs for heat treating have risen substantially driven by escalating energy costs and, more recently, skyrocketing nickel prices. Energy prices, which once represented less than 12% of typical operating costs, now often consume 20% or more of the operational budget. This has led many heat-treating operations to pursue cost-reduction programs aimed at conserving energy.

n response to these energy-conserva-tion endeavors, it has been suggested that equipping gas-fi red furnaces with sensor and control systems that

optimize the fuel-to-air ratio could lead to dramatic energy savings. Such control sys-tems are said to save substantial fuel over uncontrolled furnaces. This article will demonstrate that, al-though combustion optimization does save fuel, the cost of deploying such controls is substantially higher than the resulting fuel savings on a h eat-treating furnace. Alternative ways of achieving similar cost savings at a substantially lower investment cost will be presented.

An Overview of CombustionThe process we refer to as combustion is nothing more than the chemical com-bination of fuel and oxygen to produce heat and by-products (see sidebar). Air

– the primary source for oxygen used in combustion processes – i s comprised of oxygen (20.95%), nitrogen (78%) and traces of other gases. This is a c ritical point because nitrogen adds nothing to the combustion process and, in fact, it absorbs a signifi cant amount of the heat generated by the fuel and air. In addi-tion, nitrogen leads to the production of nitrous-oxide compounds that are regu-lated by the EPA. In perfect combustion, the oxygen and fuel combine in an ideal ratio so that nei-ther oxygen nor fuel remains after com-bustion, and the by-products are primarily carbon dioxide and water. This point of perfect combustion is commonly referred to as stoichiometry. It ensures that no un-necessary nitrogen is being heated, and it is the point where heat generation is highest and pollution emissions the low-est. Figure 1 shows a chart of combustion

effi ciency versus excess oxygen. No real combustion system, however, can ever achieve perfect combustion be-cause the fuel BTU content and fuel and airfl ow rates vary. Additionally, the uni-formity and mixing of the gases is not perfect. In reality, combustion is either oxidizing (too much oxygen) or reducing (too much fuel). Oxidizing combustion (too much oxy-gen) causes the heat loss and excess pol-lution production mentioned previously, but it also results in a shorter life for alloy components such as radiant tubes and – in the case of open-fi red furnaces – refrac-tory brick. Reducing combustion (too much fuel) produces a sooty emission as unburned fuel goes up the stacks (wasting fuel and dollars). What’s worse is that reducing combustion shortens the life of tubes even more quickly than oxidizing and can also lead to a greatly reduced burner life span. Optimized combustion within the heat treat is vital to achieving the longest pos-sible life for tubes, burners and brick and can result in substantial fuel savings.

The Economics of Combustion Control – Potential SavingsAs a general rule of thumb, for every 1% you can reduce your excess oxygen in your fi ring system, you can reduce the fuel needed to produce the same heat between 1-3% (Fig. 2). For example, if

n response to these energy-conserva-tion endeavors, it has been suggested that equipping gas-fi red furnaces with sensor and control systems that I

3%

1%

Fuel

sav

ings

Flue gas temperature, °F 1200 2000

Effi ciency

Oxygen

0 1 2 3 4 5 6Oxygen % in fl ue gas

High-effi ciency region

Fuel

CO

Fig. 1. Combustion is most effi cient be-tween 0.75% and 2% excess oxygen.

Fig. 2. Temperature dependence of com-bustion optimization: for every 1% reduc-tion in excess oxygen there is a correspond-ing 1-3% reduction in fuel use.


Analysis & Control

your furnace is currently fi ring with 10% oxygen in the exhaust fl ue and you re-duce that to 1% oxygen, you can expect a savings of at least 9% on the fuel used for that furnace. If you’re fi ring at higher temperatures you might see savings as high as 27%.

Alternate Approach: Imbalance MonitoringSo, are there options somewhere between constant manual checks of burners and full-blown combustion control? Consider an automated monitoring and alarm/noti-fi cation system, or “combustion imbalance monitoring.” Looking back to that “typical” heat-treat shop that can save about 7% on fuel,

we can now reduce the initial investment from $118,000 to about $56,000 and the annual cost from $45,000 to about $14,000. There is still no payback in fuel savings until year two, but remember that tubes will now last signifi cantly longer and the ongoing payback is now almost $24,000 per year.

ConclusionsIn spite of high gas prices and voices pushing for combustion controls on heat-treating furnaces, the economics for control simply aren’t there. Combus-tion, however, still represents an area where most heat treats can fi nd savings in the form of less fuel use, lower emis-sions and longer radiant-tube and refrac-

tory life. The way to do it economically is either manually or using an automated system to notify operators when burners are operating ineffi ciently. The savings won’t double profi ts or put a n ew shine on an old furnace, but they’re real and achievable. IH

For more information: E.S. Boltz, Y.H. Boltz,

B. Knight and P.J. Barker, Marathon Sensors

Inc., a m ember of United Process Controls,

8904 Beckett Rd., West Chester, Ohio 45069;

tel: 513-772-1000; fax: 513-326-7090; e-mail:

[email protected]; web: www.

marathonsensors.com

This article originally appeared in October 2007.

Read it in its entirety at www.industrial heating.

com/toolkit/marathon

In 1597, Francis Bacon said

Knowledge is power420 Years later, Industrial Heating eNews is delivering it to your inbox.

Sign up today – it’s free, it’s easy.

Sign up now for Industrial Heating’s daily news brief and bi-weekly newsletter at www.industrialheating.com/enews or snap this QR Code.

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Performance & E° cienc y

Alternative Energy SavingsSteeltech Limited – Grand Rapids, Mich.

Does your company’s gas consumption concern you? Industrial fuel costs are at an all-time high. As the weather warms and the driving season approaches, fuel costs will continue to increase. Natural gas is consuming a larger part of budgeted expenses every year. Researchers are investigating new sources for fuel, but the needs of the heat treater are immediate, and a solution is required today.

ndustry managers are being chal-lenged to trim costs and remain competitive with the expanding global market. Heat treaters are

seeking new technologies to help allevi-ate their growing expenses. It would be great if it were as simple as putting a lock on the thermostat and asking employees to wear warmer clothes. Natural gas is an essential component of the heat-treat industry. This is not a small concern or even a p assing one. Fossil fuels are a fi -nite resource. As our economics profes-sors taught us, as demand increases and resources dwindle, prices inevitably rise. Currently, new sources for fuel are be-ing explored. The needs of heat treaters are pressing, however, and an answer is needed as soon as possible.

Alternative Energy Solutions TechnologySteeltech has developed Alternative Ener-gy Solutions technology – known as AES – for radiant-tube assemblies used in heat-treatment furnaces. AES has been shown

to save up to 20% on natural gas costs. AES tubes use less fuel, take less time to ramp-up from ambient to cycle temperature and last twice as long as standard alloy tubes. This is due to the optimal tube design in combination with the choice of material. Double the life means less costly replace-ments and downtime. A shorter ramp-up time generates savings with reduced labor and equipment operating hours.

Laboratory Study ResultsAn independent, third-party laboratory mirrored the operating conditions for the fi eld study to thoroughly examine the performance of AES. Both the AES and standard tubes were fi red with 28% excess air (5% O

2 in the exhaust) to extend the rise time, assure the experimental preci-sion was sound and to capture any signifi -cant differences between the tubes. The observation of the radiant tubes’ performance was twofold. First measured was the time it took – w ith a 2 00,000 BTU/hr fi ring rate – t o raise the test chamber temperature from ambient to 1800°F (982°C). The second measurement was the energy required to maintain that 1800°F chamber temperature for a s ix-hour hold. The AES tube took only 35½ minutes during ramp-up, while the stan-

dard radiant tube took 52 minutes – a 32% reduction. For six hours, the total energy used to maintain a steady 1800°F (982°C) chamber temperature was measured. The AES tubes used 79,680 less BTUs than the standard tube. Table 1 illustrates the labo-ratory study results.

SummaryHeat treaters are facing numerous chal-lenges with today’s global economy. They look for help to stay competitive by re-ducing expenses and increasing effi cien-cy. Steeltech has developed a technology that aids you and your company with fuel conservation and cost-reduction strate-gies. AES can potentially deliver up to 20% fuel savings as well as reduced op-erating and labor expenses. Our success depends upon your success, and that is why we provide materials like AES – an-other opportunity to improve your bot-tom line. IH

For more information and other cost-saving

ideas, contact a Steeltech customer service

representative at 1-800-897-7833 or e-mail us

at [email protected]

This article originally appeared in June 2007.

Read it in its entirety at www.industrial heating.

com/toolkit/steeltech

seeking new technologies to help allevi-I

120,000

100,000

80,000

60,000

40,000

20,000

0

Dolla

rs

Month Year

$95,976

$7,998

Fig. 2. AES savings for a single batch furnace

Table 1. Laboratory study results

Lab Study

Step 1: Ramp-up Step 2: Steady Temperature - six hours

Minutes to 1800°FTotal Energy Used

(BTU)Average Firing Rates (BTU)

Total Energy Used (BTU)

AES 35.5 126,000 189,920 1,139,520

Standard Tube 52 177,600 203,200 1,219,200

Documents

Reference Charts & Graphs Feature Article Digest€¦ · 6 February 2008 - IndustrialHeating.com General Engineering Data 500.0 260 126.67 503.6 262 127.78 507.2 264 128.89 510.8