430F98089
&EPA
United States
Environmental Protection Agency
Air and Radiation
6202J
Draft
April 1998
EPA Coalbed Methane Outreach Program Technical Options Series
USE OF COAL MINE METHANE IN BLAST FURNACES
Gas injection systems increase the iron-making productivity ot blast furnaces while lowering costs
(Photo Courtesy of American Iron and Steel Institute)
POTENTIAL BENEFITS OF INJECTING COAL MINE METHANE IN BLASTFURNACES.
* Reduces coke usage and improved furnace stability
* Increases iron-making productivity and reduced operating costs
* Reduces air pollution from coke
+ Recovery and use of coal mine methane reduces greenhouse gas emissions
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Using coal mine
methane as fuel,
rather than venting it
to the atmosphere,
reduces methane
emissions
Blast furnaces near
gassy coal mines may
be able to use coal
mine methane to
offset a portion of their
natural gas needs
The cost of coal mine
methane is often less
than conventional
natural gas
Why Consider Using Coal Mine Methane in Blast Furnaces?
The steel industry uses blast furnaces to transform iron ores into molten iron, which
is later used for steelmaking. Blast furnace operations use metallurgical coke to
produce most of the energy required to melt the ore to iron. Currently, U.S.
steelmakers produce approximately 55 million tons of molten iron annually,
requiring about 23 million tons of coke per year. However, coke is becoming
increasingly expensive since coke production is declining for various reasons.
Since blast furnaces will continue to be the major process for producing iron in the
United States, the steel industry is seeking low-capital options that reduce coke
consumption, increase productivity, and reduce operating expenses.
All blast furnaces in North America inject some type of supplemental fuel, such as
natural gas, coke oven gas, oils and tars, or coal to form additional carbon
monoxide and hydrogen for combustion, and chemical reduction of iron-bearing
materials into molten iron. Of these fuels, natural gas and pulverized coal are the
most widely accepted for injection. Recent full-scale tests have shown that
injecting natural gas into blast furnaces at the rate of 6,900 standard cubic feet
per ton of hot metal (scf/thm) can reduce coke consumption by 30%, and can
increase ironmaking production by 40%. Injecting natural gas, rather than coal or
coke oven gas, as a supplemental fuel also reduces NOx and SOx emissions.
Coal mine methane provides the same benefits as conventional natural gas, and
could easily be substituted for, or mixed with, natural gas for blast furnace use, as
long as it meets gas quality requirements (it must have a low sulfur content and
contain at least 94% methane).
In the U.S., several blast furnaces that currently inject natural gas are located within
approximately 20 miles of gassy coal mines. Because most gassy coal mines
drain less than 10 million cubic feet of methane per day, they do not produce
enough methane to meet all the gas requirements of a typical blast furnace, but
one or more gassy mines could produce enough methane to supplement a blast
furnace's gas needs. A preliminary review suggests that a dedicated pipeline
project delivering coal mine methane to a blast furnace is not likely to be
economically viable. However, this review did not take into account many
variables, including a steel companys interest in greenhouse gas reduction
credits, locations of existing pipelines with respect to the blast furnaces, and the
potential for innovative strategies for transporting methane from a mine to a blast
furnace. These site-specific conditions could improve the economics of using
coal mine methane in blast furnaces. Internationally, there may be additional
opportunities for the use of coal mine methane in blast furnaces, as in many
countries, large metallurgical industries are located near coal mines.
Several companies are currently reporting their methane emissions reductions
under the DOE-sponsored "Voluntary Reporting Program" for greenhouse gas
emissions. At present, these emissions reductions do not have an established
market value. However, at least two companies, Niagara Mohawk Power Corp,
and Suncor Energy Inc., have taken a first step toward the creation of a global
market and an international trading system for reductions in emissions of
greenhouse gases, such as methane and carbon dioxide. Specifically, Suncor
Energy has agreed to purchase greenhouse gas emission reductions from
Niagara Mohawk. Steel companies wishing to participate in a greenhouse gas
emissions reduction program may wish to use coal mine methane to offset a
portion of their fuel needs.
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IRON
BEARING
BURDEN
FLUX
FUEL
Iron Ore 615lb
Fluxed Sinter 2484 Ib
Scrap 197 Ib
Limestone
Gravel
15lb
15lb
Coke
BLAST
Air 44,280 scf 3277 Ib
Moisture 670 scf 32 Ib
FUEL
Natural Gas 962 scf 41 Ib
TOP GAS 63,500 SCF
MOISTURE 3,300 SCF
DUST
SLAG 418lb
HOT METAL 2000 Ib
Schematic of a typical blast furnace injecting natural gas (962 scf per ton of hot metal)
The process places iron ore, coke and other fluxing substances into the furnace top (upper left
diagram) while blowing a blast of hot air enriched with natural gas into the furnace bottom
(lower left). The coke generates gases that reduce the ore, creating molten iron and slag (lower
right). The process also produces blast furnace gas, or "top gas" (upper right) that is suitable for
use in the furnace stoves or elsewhere in the plant.
Comparison of Differing Levels of Gas Injection at a Blast Furnace
(Project at Acme Steel Company in Chicago)
-
Metal production (tons/day)
Coke cost ($/THM)
Natural gas cost ($/THM)
Oxygen Cost ($/THM))
Iron Ore Pellets ($/THM)
Total Cost ($/THM)
Cost Savings ($/Day)
Increased Production ($/Day)
Total Benefits ($/Day)
Material Costs: Coke -$11 5/ton;
No Gas
Injection
2,589
$59,00
$0
$0
$57.80
$117.00
—
-
1 780 scf gas per
ton of hot metal
2,918
$52.00
$3.80
$0.10
$57.60
$113.50
$10,740
$32,900
$43,460
Natural gas - $2,20/mcf; Oxygen -
3340 scf gas per 5800 scf gas per
ton of hot metal ton of hot metal
3.124! 3,452
$48.00
$7.50
$41,00
$12.60
$2.60 ! $4,90
$57.70
115.80
$4,280
$53,500
$57,780
$57.70
$116.20
$2,420
$86,300
$88,720
$35/ton; Ore pellets - $38/ton
Abbreviations: scf - standard cubic feet; THM - tons of hot metal; mcf - thousand cubic feet
All data derived from Gas Research Institute Report, "Natural Gas Injection in Blast Furnaces"
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For More Information.
Rapidly changing environmental regulations and market conditions are creating new
opportunities for distribution and use of coal mine methane. Blast furnaces are a
high-volume gas consumer that could benefit from using coal mine methane to
meet a portion of their fuel needs. The use of coal mine methane, like conventional
natural gas, reduces coke consumption, and therefore NOx, SOx, and CO2 emissions.
In addition to these benefits, the use of coal mine methane reduces methane
emissions.
To obtain more information about using natural gas in blast furnaces, contact:
Dave Smith
Program Team Leader
Industrial Business Unit
Gas Research Institute
8600 West Bryn Mawr Avenue
Chicago, IL 60631-3562
Telephone: (773) 399-5471
Fax: (773)399-8170
To obtain information about blast furnace operations, contact:
William A. Obenchain
Manager, Manufacturing and Technology
American Iron and Steel Institute
1101 -17th Street, NW
Washington, DC 20036-4700
Telephone: (202) 452-7208
Fax: (202) 463-6573
Or contact EPA's Coalbed Methane Outreach Program for information about this and
other profitable uses for coal mine methane:
Coalbed Methane Outreach Program
U.S. EPA (6202J)
401 M Street, SW
Washington, DC 20460 USA
(202) 564-9468 or 564-9481
Fax: (202)565-2077
e-mail: fernandez.roger@epamail.epa.gov
schultz.karl@epamail.epa.gov
http://www.epa.gov/coalbed
C O A L B
METHANE
OUTREACH
P R O C R A M
The mention of products or services in this case study does not constitute an endorsement by EPA.
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