Part 2 CCT Overview
Iron Making and General Industry Technologies (Iron Making Technologies)

3A2. Pulverized Coal Injection for Blast Furnaces (PCI)
Research and development: Nippon Steel Corp. and other blast furnace steel makers
Period: Successful introduction of the technology to domestic blast furnaces started in 1981

Technology Overview

1. Background and process overview
The injection of pulverized coal into blast furnaces in Japan

4. Drying, pulverizing, and collection of coal conducted in two parallelbegan at Nippon Steel Corp.’s Oita No. 1 blast furnace in 1981.

lines, assuring stable operation of blast furnace.

Although the main reducing material in blast furnaces is coke,

5. Flow velocity of carrier air and pressure resistance of

blast furnace operators during and after the 1960s utilized heavyequipment set in consideration of prevention of fire andoil as a companion fuel, injecting it through the tuyeres toexplosions.
Bag filter

enhance the productivity, efficiency, and scaling up potential.
After the two oil crises, however, the high price of heavy oil forced

Cyclonethe producers to switch exclusively to coke, meaning coke wasRaw coal bunker

solely relied upon as the reducing material. Nevertheless, there

Receivinghopper

was a desire for an inexpensive heavy-oil-alternative companion
fuel to reduce costs and ensure the stable operation of blast

Reservoirtankfurnaces.
To this end, an ARMCO pulverized coal injection system wasP.A. fanDistributor

Feederintroduction of this technology in Japan (Fig. 1). This system

Air heater

Pulverizer

featured the following:1

1. High-pressure transportation and injection lines with no
Feed tank3

Furnace
Disperser

mechanically rotating components, thereby avoiding wear and2

Transport line

installed at the Oita No. 1 blast furnace, marking the firsttear damage.
2. No recycling of gas, assuring reliable operation.

N2 compressor

O.T.

3. Distribution of pulverized coal fed to individual tuyeres,Air compressor

ensuring uniform distribution utilizing geometrically symmetricFig. 1 Process flowchart of pulverized coal injection facility
at Oita No. 1 blast furnace

flow characteristics of fluid.

2. Development objectives and technology to be developed
Field tests of the introduced technology had been performed

2. Model plant test (1 t/hr scale) for coal treatment, transportation,abroad. Considering the differences in facility configurations andand control.

scale, as well as operating conditions in Japan versus abroad, a

3. Test to inject coal through a single tuyere into an actual furnace:study team conducted tests and investigations, focusing on theCombustibility evaluation at the tuyere of an actual furnace, asfollowing items, and reflected the results in the design.

well as the sampling and evaluation of coke inside the furnace.

1. Pulverized coal combustion test: The influence of the grade and4. The distribution of pulverized coal along the circumference:size of the pulverized coal, the temperature, pressure, and oxygen

Utilizing a prototype, studies were made to understand the powderrich condition of the air feed, and other variables were evaluated.

flow characteristics and to determine the distribution accuracy.

3. Progress and development results
Considering the heavy oil injection level during an increased

Following the domestic technology, Kobe Steel, Ltd. introduced

production rate period and the experience of long-term results, thethe U.S. Petrocarb technology and constructed the Kakogawa No.

capacity of the Oita No. 1 blast furnace was designed for 80 kg/t. Two

2 blast furnace and the Kobe No. 3 blast furnace in 1983, as themill lines, each having 25 t/hr capacity, were installed. After the start"Kobelco system." Following that, ARMCO systems wereof the plant, the equipment operation and injection operation

introduced into Nippon Steel’s Nagoya No. 1 blast furnace andfunctioned smoothly, establishing a stable production system.

Nisshin Steel Kure No. 2 blast furnace, which entered commercial

After the success of the Oita No. 1 blast furnace, Godo Steel, Ltd.

operation in 1984. In 1986, pulverized coal injection equipment

began operating an exclusively-developed system in 1982.

for blast furnaces was adopted at 16 sites in Japan, accounting

45

Clean Coal Technologies in Japan
200for 50% of the market. The number of blast furnaces employing

550

the technology had increased to 25 in 1996. In 1998, all theinjection equipment, which increased the average domestic
pulverized coal ratio to a 130 kg/t level, (Fig. 2). Table 1 shows thevarious types of injection for the blast furnace pulverized coalequipment. Table 2 shows the highest level attained in Japan for
the typical operational index of blast furnaces utilizing pulverizedcoal injection technology.

150500Coke rate (mean)

PC rate (mean)

100

450

50400

Coke rate (kg/t-pig)

PC rate (kg/t-pig), Number of PCIBF

operating domestic blast furnaces employed the pulverized coal

Number of BF equipped with PCI0
1980

1990
year

350

2000

Fig. 2 Increase in installations of pulverized coal injection
for blast furnaces technology in Japan
Table 1 Various types of pulverized coal injection equipment for blast furnaces
Type of distribution/transportation

Pneumaticconveying
concentration

Velocity

Pipe arrangement/flow rate control

Low

High

Low

Users

Investment

Carrier gas pressureand flow rate (Downtake)National Steel,
Kobe Steel,JFE (NKK)

MediumHigh

Same as above, but uptake

JFE (Kawasaki Steel)MediumHigh

Low

Same as above + Flow meter

Thyssen

Large

MediumLow

Rotary valve

Dunkerque

MediumSimon Macawber

Low

High

Coal pump

Scunthorpe

Large

ARMCO

Low

High

Uniformly distributed to give
uniform pressure drop acrossindividual pipes

Nippon Steel Corp.,
Hoogovens

SmallHighLow

Uniformly distributedby throttled pipes

Sidmar, Solac Fod

SmallHigh

Low

Same as aboveDunkerque, Taranto

Small

Low

Rotary feeder + uniform
pressure drop (one way)
distribution

Sumitomo
Metal Mining Co., Ltd.

MediumProcess

Petrocarb
DENKA
Kuettner

Pneumatic conveying
from feed tank directly
to each tuyereformerly PW

new PM
Klockner

Feed tank
Main pipe
Distributor
TuyereSumitomo
Metal Mining Co., Ltd.

Low

Table 2 Highest domestic level operational indicies for blast furnaces with pulverized coal injection
Monthandyear

Steel works, blast furnace

Coal dust ratio
kg/tCoke ratio
kg/t

Reducing material ratio
kg/tTapping ratio
t/d/m3

Maximum pulverized coal ratio (PCR)

6/98

Fukuyama No. 3 blast furnace266

289555

1.84

Minimum coke ratio (CR)

3/99

Kobe No. 3 blast furnace214288502

2.06

Minimum reducing material ratio (RAR)

3/94

Oita No. 1 blast furnace122342464

1.95

Maximum tapping ratio

1/97

Nagoya No. 1 blast furnace

137

350

487

2.63

4. Issues and feasibility of practical application
The average lifespan for domestic coke ovens has reachedinnovations to blast furnaces: recycled materials, such as waste

approximately 30 years, and the importance of pulverized coalplastics and biomass, as well as recycled ores can be injected

injection technology as a companion fuel for blast furnaces

with pulverized coal into the furnaces via tuyeres. Thus, theincreases year by year. Compared with coke, which depends ontechnology is expected to be developed as core blast furnace

caking coal, pulverized coal increases the potential for thetechnology, addressing resource, energy, and carbon dioxide

injection material owing to the adaptability of coal resources.

issues.

Pulverized coal injection technology has the potential to spur
Reference

Shinjiro Waguri: Ferram, Vol. 8, p. 371, 2003.
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