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Processing of low rank coals for various applications
Dr. R. Aeckersberg, G. Salewski, S. Schlegel
10th ECCRIA 2014-09-16
3 Processing of low rank coals @ECCRIA
1927 – Invention of "The Loesche Mill"
Ernst Curt Loesche developed the first Loesche Mill
4 Processing of low rank coals @ECCRIA
possible solution: briquetting
possible solution: drying
Low-rank coals (LRC)
low-rank coals
high water content
low gross calorific value
low energy density
prone to spontaneous combustion
5 Processing of low rank coals @ECCRIA
Typical LRC drying process – tubular dryer
drying medium: steam
steam data: ≈ 3 – 4 bar (g)
≈ 160 – 180°C
typical in combination with mine-
mouth power plant loss of electrical power due to steam
extraction in the steam turbine
Nunes: Coal upgrading (2009)
6 Processing of low rank coals @ECCRIA
LOESCHE´s Coal Enhancement Process for LRC
major features of the patented Coal Enhancement Process:
simultaneous grinding, drying and classifying of low-rank coals
high drying capacity
adjustment of the required particle size distribution of pulverized LRC for
downstream process
self-inert process
hot gas with oxygen content below limiting oxygen concentration of the
LRC
partial separation of produced coal fines in a stand-alone separator for fuel
production of hot gas generator
no additional external heat source like steam required
ATEX compliant with approved fire and explosion protection concept by
notified body
7 Processing of low rank coals @ECCRIA
Schematic flow sheet of coal enhancement
process
8 Processing of low rank coals @ECCRIA
Performed technical feasibility of process
investigated coals: 6 different lignites
VM (daf): 38.3 – 53.3 m.-%
ash (ar): 3.65 – 15.9 m.-%
water content (ar): 46.0 – 56.0 m.-%
drying and grinding on Loesche´s industrial scale mobile coal grinding
plant with production of: different residual moisture contents
different particle size distributions
binderless briquetting on optimized lab-scale double roller press: with variation of briquetting pressure
evaluation of briquette strength
Hardgrove-Index analysis of briquettes
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CGP – mobile coal grinding plant
10 Processing of low rank coals @ECCRIA
Results – Drying
LRC 1 LRC 2 LRC 3 LRC 4 LRC 5 LRC 6
raw 53.0% 53.3% 45.7% 56.4% 52.6% 52.3%
setting 1 8.7% 10.7% 7.1% 14.8% 10.7% 11.6%
setting 2 7.5% 8.0% 5.1% 10.1% 8.8% 8.6%
setting 3 5.3% 5.1% 4.3% 5.0% 7.6% 7.7%
0%
10%
20%
30%
40%
50%
60%
mo
istu
re c
on
ten
t
11 Processing of low rank coals @ECCRIA
Results - Comminution
LRC 1 LRC 2 LRC 3 LRC 4 LRC 5 LRC 6
setting 1 67.1% 52.7% 49.4% 39.2% 50.2% 41.1%
setting 2 50.5% 40.7% 30.8% 33.3% 34.5% 25.1%
setting 3 23.0% 14.3% 14.8% 18.4% 14.9% 11.0%
0%
10%
20%
30%
40%
50%
60%
70%
R90µ
m
12 Processing of low rank coals @ECCRIA
Next step – small scale industrial feasibility
demonstration plant:
product capacity: 7 tph
drying capacity: ∆H2O=48%
hot gas generator: max 6.8 MW (≈0.95 tph pulverized LRC)
use of client´s available briquetting equipment
13 Processing of low rank coals @ECCRIA
THANK YOU
FOR YOUR ATTENTION!
contact information
14 Processing of low rank coals @ECCRIA
Briquetting
modified double roller briquetting press
briquette strength evaluation
strength
abrasion
15 Processing of low rank coals @ECCRIA
Results LRC 3 – briquette strength evaluation
70
75
80
85
90
95
resid
ue
%R7,5mm %R3,0mm
reference steam coal HGI=48
16 Processing of low rank coals @ECCRIA
Results LRC 4 – briquette strength evaluation
70
75
80
85
90
95
resid
ue
%R7,5mm %R3,0mm
reference steam coal HGI=48
