Improving Cupola EfficiencyEfficiency
Robert BiggeIron Casting Research InstituteIron Casting Research Institute
DIS Annual Meeting, June DIS Annual Meeting, June 7, 2012 7, 2012 Muskegon, MichiganMuskegon, Michigan
History of ICRIHistory of ICRI• In the 1930’s a group of ironIn the 1930 s a group of iron
foundries funded research at Battelle Memorial Institute to look atMemorial Institute to look at improving cupola operations.
• Some of the researchers from Battelle were spun off to form theBattelle were spun off to form the Gray Iron Research Institute.
DIS Annual Meeting, June 7, 2012 DIS Annual Meeting, June 7, 2012 Muskegon, MichiganMuskegon, Michigan
• In the 1970’s the name was• In the 1970’s the name was changed to Iron Casting Research Institute to reflect that we wereInstitute to reflect that we were involved with all type of iron castingscastings.
DIS Annual Meeting, June 7, 2012 DIS Annual Meeting, June 7, 2012 Muskegon, MichiganMuskegon, Michigan
General CommentsGeneral Comments• Operate the cupola continuouslyp p y• Operate the cupola at constant blast• Blast rate should be in the range of• Blast rate should be in the range of
2.4 – 2.6 times the cupola cross-section in inchessection in inches
• Size tuyeres to achieve a tuyere elocit of 12 15 000 ft/min cold blastvelocity of 12-15,000 ft/min cold blast
DIS Annual Meeting, June DIS Annual Meeting, June 7, 2012 7, 2012 Muskegon, MichiganMuskegon, Michigan
General CommentsGeneral Comments
• Any changes made to improve the efficiency of the cupola will increase y pthe melt rate.
• If you can’t get rid of the additionalIf you can t get rid of the additional melted iron you are not going to maximize the cupola operationmaximize the cupola operation
DIS Annual Meeting, June 7, 2012 DIS Annual Meeting, June 7, 2012 Muskegon, MichiganMuskegon, Michigan
General Comments
• You need to work with scheduling to evenly load the molding lines to have y ga constant metal demand.
• The cupola should be sized so thatThe cupola should be sized so that the cupola is pushed to achieve the required metal demandrequired metal demand.
DIS Annual Meeting, June 7, 2012 DIS Annual Meeting, June 7, 2012 Muskegon, MichiganMuskegon, Michigan
Effect of Lining on Heat Loss
5560
Heat Loss to Shell Water Cooling
---- Unlined Cupola
35404550
Lost
Unlined Cupola---- Unlined Cupola in Meltzone---- Lined Cupola
20253035
% o
f Tot
al H
eat L
5101520%
05
30 50 70 90 110 130 150 170Diameter of Cupola Shell, inches
DIS Annual Meeting, June DIS Annual Meeting, June 7, 2012 7, 2012 Muskegon, MichiganMuskegon, Michigan
Sizing of cokegReference: Some Variables in Acid Cupola Melting; 1954 AFS Transactions
DIS Annual Meeting, June 7, 2012 DIS Annual Meeting, June 7, 2012 Muskegon, MichiganMuskegon, Michigan
Effluent Gas CompositionEffluent Gas Composition
40CO/CO2 Balance in Effluent Gas
30
35
40
15
20
25
% C
O in
Gas
5
10
15%
00 5 10 15 20 25
%CO2 in Gas
DIS Annual Meeting, June 7, 2012 DIS Annual Meeting, June 7, 2012 Muskegon, MichiganMuskegon, Michigan
Energy Loss to CO FormationEnergy Loss to CO Formation45,000
Heat Loss to CO, BTU/1000scf
30 000
35,000
40,000
1000
scf
20,000
25,000
30,000
oss
to C
O, B
TU/1
5,000
10,000
15,000
Ener
gy L
00 5 10 15 20 25 30 35 40
% CO in Gas
DIS Annual Meeting, June 7, 2012 DIS Annual Meeting, June 7, 2012 Muskegon, MichiganMuskegon, Michigan
Coke used to Generate COCoke used to Generate CO14
Total Carbon Used, #C/1000scf
10
12
scf
6
8
cons
umed
/100
0s
2
4#C
00 5 10 15 20 25 30 35 40
% CO in Effluent Gas
DIS Annual Meeting, June DIS Annual Meeting, June 7, 2012 7, 2012 Muskegon, MichiganMuskegon, Michigan
Effect of Hot BlastEffect of Hot Blast30,000
Available Energy From Heated Blast Air, BTU/1000scf
20,000
25,000
10 000
15,000
BTU
/100
0scf
5,000
10,000
00 200 400 600 800 1000 1200 1400 1600
Temperature of Blast Air, °F
DIS Annual Meeting, June 7, 2012 DIS Annual Meeting, June 7, 2012 Muskegon, MichiganMuskegon, Michigan
Divided BlastReference: Further results of investigation of improved cupola performance by proportioning the blast
between two rows of tuyeres; 1972 BCIRA Report 1057
DIS Annual Meeting, June 7, 2012 DIS Annual Meeting, June 7, 2012 Muskegon, MichiganMuskegon, Michigan
Use of OxygenygReference: Developments in Cupola Melting; 1979 BCIRA Conference paper
DIS Annual Meeting, June 7, 2012 DIS Annual Meeting, June 7, 2012 Muskegon, MichiganMuskegon, Michigan
Effect of Humidity in Blast AirEffect of Humidity in Blast AirReference: Cupola Handbook, 5th Edition; AFS
DIS Annual Meeting, June DIS Annual Meeting, June 7, 2012 7, 2012 Muskegon, MichiganMuskegon, Michigan
Savings from DehumidificationSavings from Dehumidification17,500 scfm blast rate; melting 50 TPH; operating 50% of available hours/month; $500 per ton for coke
Total Savings
$140,000
$160,000
$80,000
$100,000
$120,000
$40,000
$60,000
,
$-
$20,000
Jun-
08
Aug
-08
Oct
-08
Dec
-08
Feb-
09
Apr
-09
Jun-
09
Aug
-09
Oct
-09
Dec
-09
Feb-
10
Apr
-10
Jun-
10
Aug
-10
Oct
-10
Dec
-10
Feb-
11
Apr
-11
Jun-
11
Aug
-11
Oct
-11
Dec
-11
Feb-
12
DIS Annual Meeting, June DIS Annual Meeting, June 7, 2012 7, 2012 Muskegon, MichiganMuskegon, Michigan
Natural Gas & Liquid Fuels• In the late 60’s and early 70’s testsIn the late 60 s and early 70 s tests
were run using natural gas and fuel oil burners in the tuyeres of cupolasoil burners in the tuyeres of cupolas.
• Some of this work was actually done here in Muskegon at CWC This workhere in Muskegon at CWC. This work was done by Battelle Memorial Institute and Columbia GasInstitute and Columbia Gas.
• The burners were fired with air.
DIS Annual Meeting, June 7, 2012 DIS Annual Meeting, June 7, 2012 Muskegon, MichiganMuskegon, Michigan
Effect of Burners on Melt RateReference: Oxy-Fuel Tuyere Burners; 1966 AFS Transactions
Oxy-NG Burners Oxy-Oil Burners
UR
UR
MELTED PER
HO
MELTED PER
HO
0 LB. C
HARG
ES M
0 LB. C
HARG
ES M
ATE NO. O
F 5000
ATE NO. O
F 5000
MELTING RA
MELTING RA
DIS Annual Meeting, June 7, 2012 DIS Annual Meeting, June 7, 2012 Muskegon, MichiganMuskegon, Michigan
MELTING RATE – VERSUS – WIND RATEOXY‐OIL BURNERS – HIGH FLOWS
MELTING RATE – VERSUS – WIND RATEOXY‐GAS BURNERS – HIGH FLOWS
Natural Gas BurnersNatural Gas Burners• In the mid 90’s and later the use ofIn the mid 90 s and later the use of
natural gas burners fired with oxygen was developed in Europe and manywas developed in Europe and many papers were published. These papers all indicated reduced coke usage.a d cated educed co e usage
• I was involved with the installation of oxy-NG burners at Wheland Foundryoxy-NG burners at Wheland Foundry in the late 90’s.
DIS Annual Meeting, June 7, 2012 DIS Annual Meeting, June 7, 2012 Muskegon, MichiganMuskegon, Michigan
Natural Gas BurnersNatural Gas Burners• These burners were quite small inThese burners were quite small in
energy input. Approximately 5 million BTU/Hr total through 3 burners.BTU/Hr total through 3 burners.
We experienced an increase in melt• We experienced an increase in melt rate of 5-10%, a reduced coke consumption of approximately 5%consumption of approximately 5%, and a increase in silicon recovery.
DIS Annual Meeting, June 7, 2012 DIS Annual Meeting, June 7, 2012 Muskegon, MichiganMuskegon, Michigan
Natural Gas BurnersNatural Gas Burners• The European reports of oxy-NG p p y
burner use in the last decade have reported much more substantial pimprovements in cupola efficiency.
• The burner outputs are substantially greater than those at Whelandgreater than those at Wheland Foundry.
DIS Annual Meeting, June 7, 2012 DIS Annual Meeting, June 7, 2012 Muskegon, MichiganMuskegon, Michigan
