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Thermal Engineering / GEA EGI Co. Ltd.1
CIRCUMIX MIXER
IN DENSE SLURRY SYSTEMOF
GEA EGI Co. Ltd.
an environment friendly solution for coal fired power plants
2009
Thermal Engineering / GEA EGI Contracting/Engineering Co. Ltd.
Thermal Engineering / GEA EGI Co. Ltd.2
GENERAL DEFINITIONS OF DSS TECHNOLOGY
• „DSS” stands for „Dense Slurry System”
• „Slurry” is a mixture of water and residue of coal fired boilers
• „Slag or bottom ash or bed ash” is the rough-grained part of residue
from boiler furnace
• „Ash or fly ash” is the fine-grained residue collected by electrostatic
precipitators (ESP) or bag filters from the flue gas
• „Dense” reflects the density of slurry with a ratio around 1:1 (1 kg solid
material:1 kg water)
• „Thin” reflects the density of the slurry with a ratio around 1:10. (1 kg
solid material:10 kg water). Thin slurry is produced in the conventional
residue discharge systems
• „Mixer” is the key component of dense slurry preparation
• „CIRCUMIX” is the given name of EGI’s patented mixer equipment
Thermal Engineering / GEA EGI Co. Ltd.3
GENERAL DEFINITIONS OF DSS TECHNOLOGY
• „DSS technology” means complete environment friendly slag and
ash disposal technology of EGI based on comprehensive technology
know-how
• „Dense slurry of CIRCUMIX mixer” means
• viscous non-Newtonian fluid (Bingham plastic fluid) as water/solid material mixture to
keep solid particles in suspension in mixer and in the connecting hydraulic transport
system, even if rough-grained bottom ash is mixed together with fly ash;
• water/solid material mixture near to the stoichiometrical ratio needed to be bounded and
to be solidified with slight excess water to fill up interparticle voids promoting
transformations of ash mineral phases
• Intensive slurry homogenization and crystal nucleus generation by collisions on blades
of rotating circulation pumps in the mixer aggregate.
Thermal Engineering / GEA EGI Co. Ltd.
GENERAL DEFINITIONS OF DSS TECHNOLOGY
Continuum
Mechanics
Solid body
mechanics
Elasticity
Plasticity
Reology
Fluid
mechanics
Non-
Newtonian
fluids
Newtonian fluids
4
Thermal Engineering / GEA EGI Co. Ltd.5
HISTORY OF TECHNOLOGY DEVELOPMENT
• The first dense slurry system delivered by EGI was the ash discharge
system of Pécs Power Plant in 1991;
• The dense slurry mixer operated on batch mode. There were two
mixers operated parallel. First a mixer was filled up by a scaled
amount of makeup water, fly ash and dewatered bottom ash. A
rotating blade agitator was operated continuously in the mixer. After
a pre-set mixing time the slurry was discharged from the mixer, and
during discharge the next mixer was filled up and agitated. EGI faced
serious operational problems with bottom ash. Finally Client
decided to handle the bottom ash by trucks;
• EGI has decided to develop his own mixer type that is capable of
running continuously, to handle rough-grained bottom ash
particles (later on to mix in also FGD gypsum slurry) without
mechanical rotating blades.
• The result of the development is the patented CIRCUMIX mixer.
Thermal Engineering / GEA EGI Co. Ltd.6
DESCRIPTION OF PATENTED CIRCUMIX MIXER
• Main features of CIRCUMIX mixer
• The CIRCUMIX mixer has two main parts: pre-mixer head and mixing tank
• Agitation by slurry circulation pumps (pre-mixer and mixing tank) and
hydrodynamic internal mixing for intensive slurry homogenization, for
applying appropriate amount of mixing work per unit mass of dense slurry;
• Bottom ash can be mixed into as there are no dead zones inside for settling;
• FGD gypsum can be mixed into the dense ash slurry;
• Exhaust air venting system connected to mixing tank helps degassing of
slurry and keeping the slurry homogeneous (incompressible);
• Cleaner equipment are applied to keep clean dry-wet interfaces;
Thermal Engineering / GEA EGI Co. Ltd.7
CIRCUMIX MIXER SCHEME
Exhaust air venting
Makeup water
Pre-mixer Head
circulation
Tank circulation
Dense slurry discharge
Pre-mixer
Head
Mixing Tank
Deflector Thickened BA slurry
FGD gypsum slurry
Fly ash
Thermal Engineering / GEA EGI Co. Ltd.8
PATENT OF CIRCUMIX MIXER
• Patent header of CIRCUMIX mixer equipment
Thermal Engineering / GEA EGI Co. Ltd.9
PATENT OF CLEANING APPARATUS
• Hydromechanical Mixing Apparatus
Thermal Engineering / GEA EGI Co. Ltd.1010
DENSE SLURRY MIXER EQUIPMENT LINE
of CIRCUMIX mixer referencesThe size and capacity variation
2001.
Q =120 m/hslurry
3
Tendering Phase
NEYVELI LIGNITE CORP.
JEA PP
slurryQ =100 m/h3
MÁTRA POWER PLANT Co. Ltd.
Q =240 m/h
1999.
slurry
3
VISONTA PLANT
Size and capacity development of CIRCUMIX mixer projects
Thermal Engineering / GEA EGI Co. Ltd.1111
DENSE SLURRY MIXER ARRANGEMENT
Mixer Tank Circulation
PumpPre-mixer Head
Circulation Pump
Mixer Exhaust Venting
System
Fly Ash Dosing Silo
Thermal Engineering / GEA EGI Co. Ltd.12
MAIN MILESTONES OF CIRCUMIX DEVELOPMENT
• Testing of dense slurry sample properties made by laboratory scale
and by EGI’s semi-industrial mobile mixer with residues from several
coal fired power plants;
• Support the appropriate test procedures applied at laboratories of
environmental authorities considering the specialties of dense slurry
disposal field (effect of aging, way of sampling, etc.);
• Collecting qualifications based on tests mentioned above for potential
Clients without and with FGD gypsum;
• Studies at three different universities and other specialists for
rheological, sedimentation, transportation and solidification properties
of dense slurries;
Thermal Engineering / GEA EGI Co. Ltd.13
LABORATORY TESTS AND STUDIES
• Ash particle size distribution measurements;
• Ash particle density measurements;
• Ash chemical composition measurements;
• Ash mineral phases measurements mainly for evaluating CaO forms;
• Rheological tests of dense slurry at different solids concentration by
pipe viscometer;
• Stress analysis of test cubes
Thermal Engineering / GEA EGI Co. Ltd.14
LABORATORY TESTS AND STUDIES FOR DSS APPLICATIONS
Eesti PP / Narva Power Plants
Particle size distribution of ash samples of PCB and CFB
0
10
20
30
40
50
60
70
80
90
100
10 100 1000
Particle size, micro-meter
Un
ders
ize, w
t%
Furnace bottom ash
Coarse fly ash
Fine fly ash
PCB ash
CFB ash
Technical University of Miskolc
Thermal Engineering / GEA EGI Co. Ltd.15
Technical University of Veszprém
Oxides composition of generated total ash of CFB unit #8 of Eesti PPCFB ash
CaO
30.93%
SiO2
32.51%
MgO
5.17%
Al2O3
7.44%
Fe2O3
4.21%
Na2O
0.13%
K2O
3.38%
TiO2
0.10%
SO3
5.68%
Cl2
0.18%
Ignition loss (810 °C)
10.25%
LABORATORY TESTS AND STUDIES FOR DSS APPLICATIONS
Thermal Engineering / GEA EGI Co. Ltd.16
COMPUTER FLOW DYNAMIC DSS MIXER MODEL
• Computer flow dynamic model and physical model was developed for
developing CIRCUMIX technology to study effect of mixer size, slurry
recirculation and for aiding appropriate design of other mixer details);
• Preliminary modeling were required to select optimal grid
arrangement, the best fitting turbulence model, etc.
• Physical model was built to compare measured and calculated
velocity profiles.
Thermal Engineering / GEA EGI Co. Ltd.17
DSS MIXER MODEL AND COMPUTER FLOW DYNAMIC
Budapest University of Technology and Economics
Thermal Engineering / GEA EGI Co. Ltd.18
COMPUTER FLOW DYNAMIC DSS MIXER MODEL
Extract from presentation abstract for Multiphase Flows Workshop
26-28 May 2009, Dresden-Rossendorf
Numerical simulation and measurements of the free surface flow in a
hydrodynamic mixer
Cs. Hős(1), Gy. Paál(1), G. Walter(2)
Corresponding author: Cs. Hős, [email protected]
(1) Department of Hydrodynamic Systems
Budapest University of Technology and Economics
(2) GEA EGI Contracting / Engineering Co. Ltd.
Thermal Engineering / GEA EGI Co. Ltd.19
This part of the presentation deals with the numerical simulation of a mixer
consisting of a cyclon-like cylinder in which the free-surface swirling water flow
is driven by two tangential water jets above the water level. The challenge in
this problem was to properly capture the velocity distribution and the free water
surface. 3D unsteady simulations were performed with SST and SSG
turbulence models in a geometry containing 800k cells.
A test rig was built in which -beside the visual access to the whole fluid domain
–velocity measurements were performed using turbine flow meters. The
circumferential velocity component was measured along several radial and
axial lines and compared to the simulation results showing reasonable
agreement.
COMPUTER FLOW DYNAMIC DSS MIXER MODEL
Thermal Engineering / GEA EGI Co. Ltd.20
COMPREHENSIVE DENSE SLURRY SYSTEM
Dry Fly Ash
Collection
Makeup Water
Treatment
Makeup Water
Surge Tank
Bottom
Storage Bin
Fly Ash
Storage Silo
Dense Slurry
Transport
Dense Slurry
Deposition
Dense Slurry
CIRCUMIX Mixer
Dry Bottom Ash
Collection /
Treatment
Thermal Engineering / GEA EGI Co. Ltd.21
DENSE SLURRY SYSTEM
• BA slurry handling
• EGI DSS technology includes bottom ash slurry thickeners and clean
water return back to ash flushing at operating boilers;
• Oversize particles of bottom ash slurry are separated and collected in
waste container;
• Thickened bottom ash slurry is pumped into operating dense slurry
mixer(s);
• FGD gypsum slurry handling
• CIRCUMIX mixers can accept FGD gypsum slurry flow from gypsum
slurry reservoir;
• FGD gypsum slurry flow is monitored and the final dense slurry quality is
protected from unacceptably high gypsum content;
Thermal Engineering / GEA EGI Co. Ltd.22
• I&C
• The control system is part of the technology know-how of EGI;
• Equipment have their on PLC controls and on top level a DCS system
controls the whole ash handling technology;
• The ash discharge system is operated by issuing automatic operational
sequences from the operator station of the ash handling plant;
• Closed and open loop controls helps automatic system operation;
• Alarms and protections are for avoiding forced outages;
• Management system helps scheduling maintenance;
DENSE SLURRY SYSTEM
Thermal Engineering / GEA EGI Co. Ltd.2323
BOTTOM ASH SLURRY THICKENER
Thermal Engineering / GEA EGI Co. Ltd.24
ECOLOGYCAL FEATURES OF DSS TECHNOLOGY
• The dense slurry is deposited generally onto a plain ash field area.
The ash field is divided into smaller size slurry cassettes – one for
operation and the other for stand by.
• The cassette is surrounded by dike made from own material
excavated from deposited dense slurry.
• On the top of the dike are the dense slurry distribution pipes, and at
even positions dense slurry discharge pipe can be connected.
Thermal Engineering / GEA EGI Co. Ltd.25
ECOLOGYCAL FEATURES OF DSS TECHNOLOGY
• Water requirement is low. Zero waste water plant is achievable by
mixing in plant waste waters, including water treatment plant and
flue gas desulphurization
• No return water system from ash disposal area should be operated
• After mineral transformation of settled dense ash slurry, ash stone is
developed icharacterized by
• low water leakage to surface and ground water systems
• low dissolution of ash components
• embedded hazardous components
• acceptable strength and stability
Thermal Engineering / GEA EGI Co. Ltd.26
ECOLOGYCAL FEATURES OF DSS TECHNOLOGY
• The developed, settled and aged ash layers are mechanically stable,
there is no dusting by wind, and the rain leakage through the ash has
environmentally acceptable quality.
• The ash field height can be increased layer by layer. The compressive
strength of the deposited ash allows to built high ash storage fields.
• The side surfaces are covered by thin earth layer, and by some
plantations the field can easily be recultivated.
Thermal Engineering / GEA EGI Co. Ltd.2727
BASIC ASH TRANSFORMATIONS
Slaking, calcium and sulfate ion generation:
CaO + H2O → Ca(OH)2 FAST
CaSO4 + H2O → Ca++ + SO4-- FAST
Ettringit formation:
Ca++ + OH- + SO4-- + Al2O3 + H2O →
3CaOAl2O3 3CaSO4 31-32H2O INITIALLY FAST
Calcium silicate hydrates formation:
Ca++ + OH- + SiO2 + H2O → CSH MINOR REACTION
Thermal Engineering / GEA EGI Co. Ltd.2828
ASH STONE PROPERTIES
Compressive strength and leakage data for 90 days ash stone formed from dense ash slurry of a high CaO content ash (according to DIN standards):
Sample W/S Strength Leakage
kg/kg kN/m2 m/s
I-3-F 1:1 4182
I-2-K-11 1:1 1936 <E-12
II-1-F 0.8:1 13043 <E-12
II-3-F 0.8:1 8571 <E-12
II-2-K-7 0.8:1 4670 2.2E-11
II-2-K-1 0.8:1 5586 3.7E-06 (30 days old)
Thermal Engineering / GEA EGI Co. Ltd.2929
Dense ash slurry disposal area (typical)
EXISTING DAM
PLANNED BOUNDARY
PLANNED SEPARATOR DAM
EAST SIDE
OPTIONAL FOIL COVERAGE
DISTANCE SLURRY LINE
MONITORING STATION
WATER COLLECTING WELLS
ASH FIELD NO 1
WATER DRAIN
WEST SIDE
EXCESS WATER DITCH
STEEP SLOPE
DISCHARGE SUPPORT
CULTIVATION OF DISPOSAL AREA
Thermal Engineering / GEA EGI Co. Ltd.3030
DENSE SLURRY LANDFILL DISCHARGE
Thermal Engineering / GEA EGI Co. Ltd.3131
DENSE SLURRY SYSTEM, LANDFILL AREA
Thermal Engineering / GEA EGI Co. Ltd.32
MARKET OF DSS TECHNOLOGY
• EGI DSS technology means complex environmentally sound solution
for Clients:
• by replacement of obsolete thin ash slurry systems at existing
power plants. Retrofitting of existing bottom ash and fly ash
collection systems (if it is required by environmental agencies);
• by fitting an environmentally acceptable ash disposal technology at
new plants.
Thermal Engineering / GEA EGI Co. Ltd.33
REFERENCE PLANTS - ROMANIA
Purchase Order No. with complete postal
AddressLocation Year
HCSD DSS Plant Capacity
Bottom
Ash
TPH
Fly Ash
TPH
Total
Ash
TPH
SC Colterm SA
Timisoara Sud Power Plant, Romania
Episcop Joseph
Lonovici, 4
Timisoara
300092, Romania
2000 20 20
SC Colterm SA
Timisoara Sud Power Plant Ext., Romania
Episcop Joseph
Lonovici, 4
Timisoara
300092, Romania
2007 3 17 20
Romelectro, Romania
Rovinari Power Plant 6X330 MWe,
Romania
020371, Bucureşti,
Sector 2
Bulevardul Lacul
Tei, Nr. 1-3
2009 4x30
4x127
FA
+4x33
gypsum
4x190
Romelectro, Romania
Craiova-II Power Plant 2X150 MWe,
Romania
020371, Bucureşti,
Sector 2
Bulevardul Lacul
Tei, Nr. 1-3
2009 4x9.2
4x51 FA
+4x17.3
gypsum
4x77.5
Romelectro, Romania
Isalnita Power Plant 2X315 MWe
020371, Bucureşti,
Sector 2
Bulevardul Lacul
Tei, Nr. 1-3
2009 4x7
4x55.2
FA
+4x20
gypsum
4x82.2
Thermal Engineering / GEA EGI Co. Ltd.34
REFERENCE PLANTS - ROMANIA
• Listed Romanian projects No. 1 and 2 are completed and are
operating. The first installation originally was designed as pilot plant
for Romanian plants to test dense slurry handling system properties in
semi industrial scale.
• After the pilot plant was operated for years without problem, the Client
had decided to extend the dense slurry system capacity for the full
plant.
• Projects No. 3, 4 and 5 are running projects. All EGI equipment are at
site, but the EPC Contractor is in delay because of different reasons
(financial, etc.). Commissioning of these projects are expected in the
near future.
Thermal Engineering / GEA EGI Co. Ltd.35
REFERENCE PLANTS - ROMANIA
• A new Romanian project is the ash handling system delivery for
Turceni Power Plant. This ash handling system will be similar to
Rovinari case, but the installed total ash discharge capacity will be
twice. EGI has good chance to participate (tender was submitted on
30 July, 2009.)
• Recently a New Romanian tender has been issued for Paroseni
Power Plant. (Tender was submitted on 20 August, 2009.)
Thermal Engineering / GEA EGI Co. Ltd.36
ROVINARI POWER PLANT - ROMANIA
• Next slides demonstrate first the assembly schedule of Rovinari PP
Dense slurry mixers for a unit.
• Next a photo shows mixer tank before dispatch
• And finally three selected operator graphic diagrams are shown.
Thermal Engineering / GEA EGI Co. Ltd.37
ROVINARI POWER PLANT - ROMANIA
GEA EGI Power & Process Technology
Ash silo
Thermal Engineering / GEA EGI Co. Ltd.38
ROVINARI POWER PLANT - ROMANIA
GEA EGI Power & Process Technology
Ash silo
CIRCUMIX
mixers
Thermal Engineering / GEA EGI Co. Ltd.GEA EGI Power & Process Technology3939
Detailed design phase
Budapest, 21st October, 2008.
Ash silo
CIRCUMIX
mixers
Head and tank
recirculation
pumps
Thermal Engineering / GEA EGI Co. Ltd.GEA EGI Power & Process Technology4040 Budapest, 21st October, 2008.
Ash silo
CIRCUMIX
mixers
Head and tank
recirculation
pumps
Platforms
Thermal Engineering / GEA EGI Co. Ltd.GEA EGI Power & Process Technology4141 Budapest, 21st October, 2008.
Ash silo
CIRCUMIX
mixers
Head and tank
recirculation
pumps
Platforms
Rotary ash
feeders
Thermal Engineering / GEA EGI Co. Ltd.GEA EGI Power & Process Technology4242 Budapest, 21st October, 2008.
Ash silo
CIRCUMIX
mixers
Head and tank
recirculation
pumps
Platforms
Rotary ash
feeders
Head
recirculation
pipelines
Thermal Engineering / GEA EGI Co. Ltd.GEA EGI Power & Process Technology4343 Budapest, 21st October, 2008.
Ash silo
CIRCUMIX
mixers
Head and tank
recirculation
pumps
Platforms
Rotary ash
feeders
Head
recirculation
pipelines
Tank
recirculation
pipelines
Thermal Engineering / GEA EGI Co. Ltd.GEA EGI Power & Process Technology4444 Budapest, 21st October, 2008.
Ash silo
CIRCUMIX
mixers
Head and tank
recirculation
pumps
Platforms
Rotary ash
feeders
Head
recirculation
pipelines
Tank
recirculation
pipelines
Make up water
Thermal Engineering / GEA EGI Co. Ltd.GEA EGI Power & Process Technology4545 Budapest, 21st October, 2008.
Ash silo
CIRCUMIX
mixers
Head and tank
recirculation
pumps
Platforms
Rotary ash
feeders
Head
recirculation
pipelines
Tank
recirculation
pipelines
Make up water
Flushing water
Thermal Engineering / GEA EGI Co. Ltd.GEA EGI Power & Process Technology4646 Budapest, 21st October, 2008.
Ash silo
CIRCUMIX
mixers
Head and tank
recirculation
pumps
Platforms
Rotary ash
feeders
Head
recirculation
pipelines
Tank
recirculation
pipelines
Make up water
Flushing water
Exhaust air
filters
Thermal Engineering / GEA EGI Co. Ltd.GEA EGI Power & Process Technology4747 Budapest, 21st October, 2008.
Exhaust air
filters
Exhaust air
pipelines
Ash silo
CIRCUMIX
mixers
Head and tank
recirculation
pumps
Platforms
Rotary ash
feeders
Head
recirculation
pipelines
Tank
recirculation
pipelines
Make up water
Flushing water
Thermal Engineering / GEA EGI Co. Ltd.GEA EGI Power & Process Technology4848 Budapest, 21st October, 2008.
Exhaust air
filters
Exhaust air
pipelines
Gypsum slurry
pipelines
Ash silo
CIRCUMIX
mixers
Head and tank
recirculation
pumps
Platforms
Rotary ash
feeders
Head
recirculation
pipelines
Tank
recirculation
pipelines
Make up water
Flushing water
Thermal Engineering / GEA EGI Co. Ltd.4949
ABRASIVE RESISTANT INTERNAL LINING
Thermal Engineering / GEA EGI Co. Ltd.5050
PRE-ERECTION IN HUNGARY
Thermal Engineering / GEA EGI Co. Ltd.5151
PREPARATION FOR TRANSPORTATION
Thermal Engineering / GEA EGI Co. Ltd.5252
DENSE SLURRY DCS SOFTWARE –CIRCUMIX MIXER
Thermal Engineering / GEA EGI Co. Ltd.5353
DENSE SLURRY DCS SOFTWARE - THICKENERS
Thermal Engineering / GEA EGI Co. Ltd.5454
DENSE SLURRY DCS SOFTWARE –LONG DISTANCE TRANSPORTATION
Thermal Engineering / GEA EGI Co. Ltd.5555
• JEA Jacksonville Northside Generating Station / USA/ 2x300 MWe CFB
circulating fluidized bed boiler based on petroleum coke (90 %) and coal
(10 %) fuel. The boiler is the largest CFB boiler on the world.
2x62,5 tons/h of fly ash + 2x62,5 tons/h of bed ash mixing units (high CaSO4
fly ash / high CaO bed ash)
CIRCUMIX continuous mixing technology
Bed ash and fly ash slurry handling
Slurry distance transport
2 sets of piston diaphragm type slurry pump (GEHO)
1,7 km slurry transport distance
Commissioned: 2002
REFERENCE PLANTS - JEA
Thermal Engineering / GEA EGI Co. Ltd.5656
JEA 120 TPH DENSE ASH SLURRY MIXER, BED ASH MIXER HEAD AND TANK
Thermal Engineering / GEA EGI Co. Ltd.
5757
JEA 120 T/H DENSE SLURRY MIXER, LANDFILL AREA
Walking on the surface of 24 hours ash stone
Thermal Engineering / GEA EGI Co. Ltd.5858
PROJECT HANDLING – TECHNICAL
Tendering phase
• Physical and chemical analysis of residues
• Test cubes preparation by mobile mixer
• Computer flow dynamic model
• Design data by calculation software
Design phase
• Standardized modules
• 3D model preparation
• Pipe stress analysis
• Own software application in DCS system
• Full scale software test by simulation in EGI
Thermal Engineering / GEA EGI Co. Ltd.5959
PROJECT HANDLING – TECHNICAL
Manufacturing phase
• Continuous quality assurance and expediting
• Pre-erection at workshop in Hungary
• Geometrical verification by laser scanner
• Well-documented package transportation
Erection and commissioning phase
• Supervision by EGI’s experts deeply involved in the projects from
the beginning