In fluidized-bed combustion and gasification of biomass and waste, agglomeration of bed/ash particles is a major problem area. This paper deals with a new method for monitoring and controlling fluidized-bed hydrodynamics, which enables the recognition of agglomeration in an early stage and provides control measures to prevent further agglomeration and defluidization. The method, called early agglomeration recognition system (EARS), is based on recognizing significant differences between reference time series of pressure fluctuations and successive time series measured during prolonged plant operation. The early recognition provides a time interval for taking dedicated actions to counteract the agglomeration. Thus, EARS can be a tool to help plant operators prevent agglomeration-induced plant shutdowns and minimize bed material makeup and residue production. Results are presented of small-scale experiments showing the effectiveness and selectivity of the early agglomeration recognition. Subsequently, the development of control strategies is discussed.

1.
Visser
,
H. J. M.
,
Hofmans
,
H.
,
Huijnen
,
H.
,
Kastelein
,
R.
, and
Kiel
,
J. H. A.
, 2001, “
Biomass Ash-Bed Material Interactions Leading to Agglomeration in Fluidized Bed Combustion and Gasification
,”
Progress in Thermochem Biomass Conversion
,
A. V.
Bridgwater
, ed.,
Blackwell Science
, Vol.
1
, pp.
272
286
.
2.
Visser
,
H. J. M.
,
Van Lith
,
S.
, and
Kiel
,
J. H. A.
, 2002, “
Biomass Ash-Bed Material Interactions Leading to Agglomeration in Fluidized Bed Combustion and Gasification
,”
Proceedings of the 12th European Conference and Technology, Exhibition on Biomass for Energy, Industry and Climate Protection
, V 2.43,
Amsterdam
, June 17–21.
3.
Kiel
,
J. H. A.
,
Korbee
,
R.
,
Van Ommen
,
J. R.
,
Nijenhuis
,
J.
, and
Van den Bleek
,
C. M.
, 2002, “
Early Agglomeration Recognition System (EARS)
,”
Proceedings 12th European Conference and Technology Exhibition on Biomass for Energy, Industry and Climate Protection
, ETA-Florence,
Florence, Italy
, pp.
589
592
.
4.
Van Ommen
,
J. R.
,
Coppens
,
M.-O.
,
Van den Bleek
,
C. M.
, and
Schouten
,
J. C.
, 2000, “
Early Warning of Agglomeration in Fluidized Beds by Attractor Comparison
,”
AIChE J.
0001-1541,
46
, pp.
2183
2197
.
5.
Schouten
,
J. C.
, and
Van den Bleek
,
C. M.
, 1998, “
Monitoring the Quality of Fluidization Using the Short-Term Predictability of Pressure Fluctuations
,”
AIChE J.
0001-1541,
44
(
1
), pp.
48
60
.
6.
Van der Drift
,
A.
,
Visser
,
H. J. M.
, and
Olsen
,
V.
, 2001, “
Prediction and Solution Methods for Ash Agglomeration and Related Problems During Biomass Conversion
,”
Proceedings of the 1st World Conference on Biomass for Energy and Industry
,
James and James
,
London, UK
, pp.
485
488
.
7.
Kai
,
T.
, and
Furusaki
,
S.
, 1987, “
Methanation of Carbon Dioxide and Fluidization Quality in a Fluidized Bed Reactor—The Influence of a Decrease in Gas Volume
,”
Chem. Eng. Sci.
0009-2509,
42
, pp.
335
339
.
8.
Chong
,
Y. O.
,
O’Dea
,
D. P.
,
White
,
E. T.
,
Lee
,
P. L.
, and
Leung
,
L. S.
, 1987, “
Control of Quality of Fluidization in a Tall Bed Using the Variance of Pressure Fluctuations
,”
Powder Technol.
0032-5910,
53
, pp.
237
246
.
9.
Svensson
,
A.
,
Johnsson
,
F.
, and
Leckner
,
B.
, 1996, “
Fluidization Regimes in Nonslugging Fluidized Beds: The Influence of Pressure Drop Across the Air Distributor
,”
Powder Technol.
0032-5910,
86
, pp.
299
312
.
10.
Van Ommen
,
J. R.
,
Schouten
,
J. C.
, and
Van den Bleek
,
C. M.
, 1999, “
An Early-Warning-Method for Detecting Bed Agglomeration in Fluidized Bed Combustors
,”
Proceedings of the 15th International Conference on Fluidized Bed Combustion
,
R. B.
Reuther
, ed., ASME, New York, Paper No. 150.
11.
Daw
,
C. S.
, and
Halow
,
J. S.
, 1993, “
Evaluations and Control of Fluidization Quality Through Chaotic Time Series Analysis of Pressure-Drop Measurements
,”
AIChE Symp. Ser.
0065-8812,
89
(
296
), pp.
103
122
.
12.
Finney
,
C. E. A.
,
Nguyen
,
K.
,
Daw
,
C. S.
, and
Halow
,
J. S.
, 1998, “
Symbol-Sequence Statistics for Monitoring Fluidization
,”
Proceedings of the ASME Heat Transfer Division
, Vol.
5
,
R. A.
Nelson
Jr.
,
T.
Chopin
, and
S. T.
Thynell
, eds., ASME, New York, pp.
405
411
.
13.
Daw
,
C. S.
,
Finney
,
C. E. A.
,
Nguyen
,
K.
, and
Halow
,
J. S.
, 1998, “
Symbol Statistics: A New Tool for Understanding Multiphase Flow Phenomena
,”
Proceedings of the ASME Heat Transfer Division
, Vol.
5
,
R. A.
Nelson
Jr.
,
T.
Chopin
, and
S. T.
Thynell
, eds., ASME, New York, pp.
221
229
.
14.
Van Ommen
,
J. R.
,
Schouten
,
J. C.
,
Coppens
,
M.-O.
,
Lin
,
W.
,
Dam-Johansen
,
K.
, and
Van den Bleek
,
C. M.
, 2001, “
Timely Detection of Agglomeration in Biomass Fired Fluidized Beds
,”
Proceedings of the 16th International Conference on Fluidized Bed Combustion
,
D. W.
Geiling
, ed., ASME, New York, Paper No. 131.
15.
Van Ommen
,
J. R.
,
Schouten
,
J. C.
,
Van der Stappen
,
M. L. M.
, and
Van den Bleek
,
C. M.
, 2000, “
Response Characteristics of Probe-Transducer Systems for Pressure Measurements in Gas-Solid Fluidized Beds: How to Prevent Pitfalls in Dynamic Pressure Measurements
,”
Powder Technol.
0032-5910,
106
, pp.
199
218
;
Erratum:
Van Ommen
,
J. R.
,
Schouten
,
J. C.
,
Van der Stappen
,
M. L. M.
, and
Van den Bleek
,
C. M.
,
Powder Technol.
0032-5910
113
, p.
217
, 2000.
You do not currently have access to this content.