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

3A3. Direct Iron Ore Smelting Reduction Process (DIOS)
Research and development: Japan Coal Energy Center; and Japan Iron and Steel Federation
Period: 1988-1995 (8 years)

Technology Overview

1. Overview

3. Results of study

The Direct Iron Ore Smelting Reduction Process (DIOS) directly

A feasibility study was undertaken on the installation of a newuses noncaking coal in a powder or granular form, and iron ore

commercial blast furnace plant and of DIOS in a waterfront area.

without the use of coke or a sintering process, which are normally

Considering its superiority to the blast furnace process as

required in blast furnace processes. The noncaking coal isdescribed below, the feasibility of DIOS can be demonstrated for

directly fed to a smelting reduction furnace, while the iron ore is

a 6,000 ton molten iron model production facility (annualpreliminarily reduced before being fed to the furnace, thus

production of 2 million tons).

producing molten iron.

1. Investment cost reduced by 35%.
2. Molten iron production cost decreased by 19%.

2. Features

3. Coal consumed, 730-750 kg per 1 ton of molten iron production,

1. Possibility of utilizing inexpensive raw materials and fuelequivalent to that of the blast furnace process.

(noncaking coal, in-house dust, etc.)

4. Net energy consumption decreased by 3 to 4%.

2. Low operating cost

5. CO2 emissions in the iron making process decreased by 4 to

3. Responds flexibly to variations in production rate5%.

4. Compact and small incremental investment
5. Stable, high-quality supply of iron source available
6. Effective use of coal energy
7. Easy co-production of energy (co-generation)
8. Low environmental load (low SOx, NOx, CO2, dust generation,
no coke oven gas leaks)
4. Research and development progress
Table 1 Research and development progress
Fiscal year

1988

1989

1990

1991

1992

1993

1994

1995

Core technology study

Construction
Test operation

Pilot plant test

1) Core technology study (FY1988-FY1990)

2. With various raw materials, the equipment and operatingCore technologies necessary for the construction of the pilot

specifications to achieve high thermal efficiency, as an alternativeplant were established. These core technologies include anto the blast furnace, were determined.

increase in the thermal efficiency of a smelting reduction furnace

3. Technologyforwater-coolingthefurnacebodywas(SRF), the technology to be integrated with a preliminary

established. A conceptual design and an economic evaluation

reduction furnace (PRF), the molten slag discharge technology,(FS) for commercial facilities was conducted. The conditions ofand the scale-up of an SRF.

the facilities and of the operations to prove the superiority versus

2) Pilot plant test (FY1993-FY1995)

the blast furnace, as shown in the results of the research, was

1. The possibility of directly using powder, granular ore, and coalclarified.

was confirmed, and necessary equipment specifications weredetermined.

47

Clean Coal Technologies in Japan

Coal952kg

Flux80kg

Plant size

500 t-molten iron/day

Smelting reduction
furnace

Height 9.3m
Inner diameter 3.7m
Pressure less than 2.0kg/cm2 — G (300kPa)

Pre-reduction
furnace

Height 8.0m
Inner diameter 2.7m

Iron ore
1450kgPre-heating
furnaceRD 8.7%2,326Nm3
2,789Mcal (11.7GJ)

RD 8.6%600 CO

Pre-reduction
furnace
Venturi scrubber
RD 27.0%779 COO2608Nm3RD 27.1%

Pressure control valve

OD 31.6%
Off-gasTapping device
Smelting reduction
furnace
1.9kg/cm2 — G (290kPa)
Molten iron

24.7t/h
1,540OC
1,000kg
Legend

N2 70Nm3

OD: Oxidation degree
RD: Reduction degree

Fig. 1 Process flowchart for DIOS pilot plant (per 1,000kg of molten iron)48