Ikelic - Alliance Digital Repository

COAL
Process Description
In the HYCOL process, powdered coal is
pneumatically conveyed using nitrogen, and intro
duced with oxygen into the gasifier through two
stages of tangential multi-burners; four burners
arranged in each stage. The gasifier, operating
at 3 MPa and up to 1,800C, converts the coal to
a synthesis gas. Most of the ash in the coal
melts and circulates down along the wall of the
gasifier as molten slag, and eventually exits the
gasifier mainly through the outer slag tap holes in
the bottom. The slag is quenched, solidified in a
water bath, and crushed by the slag crusher,
then removed via lockhoppers. When the hot
gas exits the gasifier, recycle cooled gas and
steam are mixed to quench the gas so that the
solids in the hot gas are no longer sticky
(Figure 2).
The solids in the synthesis gas, termed recycle
char, are removed from the gas in double hot
Heat Recovery
Zone
FIGURE 2
cyclones. The recovered char, at about 300C, is
circulated to the gasifier via lockhoppers and a
pneumatic conveying system. This achieves
higher carbon conversion and allows a greater
recovery
of the coal ash as slag.
Technological Features
To achieve high gasification efficiency and ap
plicability to a wide range of coals, the HYCOL
gasifier has the following features:
- The
oxygen-blown one-chamber with
two-step
HYCOL PLANT CONFIGURATION
.Water.
(Quench)
Radiant"
Boiler
f CoaVOxygen
Gasification (Upper Burners)
Zone
CoaVOxygen
4 (Lower Burners)
Slag Quenching
Zone
HYCOL Reactor
SOURCE: MATSUOKA ET AL.
<
O
Oil Burner V Crusher
spiral flow concept lengthens
the residence time of coal particles in the
gasification zone, and thus enables a
higher gasification efficiency with com
pact reactor size. In addition, a wide
range of split ratios of coal and oxygen
fed to upper and lower burners can be
chosen independently to obtain optimum
gasification efficiency with a wide
Recycte (Quench)
Hot CyctoneJ nel i Convectj
1 r> Boiler
g &
Y
on Shifter
Steam
(Quench)
' Char/Oxygen/Steam
(Char Burner)
Slag
4-36
r\
E
Cooled Gas
Scrubber
| Wash Water
THE SYNTHETIC FUELS REPORT, JANUARY 1995