Circumix Dense Slurry Technology

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.


GENERAL DEFINITIONS OF DSS TECHNOLOGY

stands for Slurry

is a mixture of water and residue of coal fired boilers

or bottom ash or bed is the rough-grained part of residue

from boiler furnace

or fly is the fine-grained residue collected by electrostatic

precipitators (ESP) or bag filters from the flue gas

reflects the density of slurry with a ratio around 1:1 (1 kg solid

material:1 kg water)

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

is the key component of dense slurry preparation

is the given name of patented mixer equipment



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.


Continuum

Mechanics

Solid body

mechanics

Elasticity

Plasticity

Reology

Fluid

mechanics

Non-

Newtonian

fluids

Newtonian fluids

4


HISTORY OF TECHNOLOGY DEVELOPMENT

The first dense slurry system delivered by EGI was the ash discharge

system of 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.


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;


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


PATENT OF CIRCUMIX MIXER

Patent header of CIRCUMIX mixer equipment


PATENT OF CLEANING APPARATUS

Hydromechanical Mixing Apparatus


DENSE SLURRY MIXER EQUIPMENT LINE

of CIRCUMIX mixer referencesThe size and capacity variation

2001.

Q =120 m/hslurry3

Tendering Phase

NEYVELI LIGNITE CORP.

JEA PP

slurryQ =100 m/h3

MTRA POWER PLANT Co. Ltd.

Q =240 m/h

1999.

slurry

3

VISONTA PLANT

Size and capacity development of CIRCUMIX mixer projects


DENSE SLURRY MIXER ARRANGEMENT

Mixer Tank Circulation

PumpPre-mixer Head

Circulation Pump

Mixer Exhaust Venting

System

Fly Ash Dosing Silo


MAIN MILESTONES OF CIRCUMIX DEVELOPMENT

Testing of dense slurry sample properties made by laboratory scale

and by 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;


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


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


Technical

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


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.


DSS MIXER MODEL AND COMPUTER FLOW DYNAMIC

Budapest University of Technology and Economics



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

1 1), G. Walter(2)

(1) Department of Hydrodynamic Systems

Budapest University of Technology and Economics

(2) GEA EGI Contracting / Engineering Co. Ltd.


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.



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


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;


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


BOTTOM ASH SLURRY THICKENER


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.



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



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.


BASIC ASH TRANSFORMATIONS

Slaking, calcium and sulfate ion generation:

CaO + H2O 2 FAST

CaSO4 + H2++ + SO4

-- FAST

Ettringit formation:

Ca++ + OH- + SO4-- + Al2O3 + H2

3CaO Al2O3 3CaSO4 31-32H2O INITIALLY FAST

Calcium silicate hydrates formation:

Ca++ + OH- + SiO2 + H2 MINOR REACTION


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


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


DENSE SLURRY LANDFILL DISCHARGE


DENSE SLURRY SYSTEM, LANDFILL AREA


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.


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

Sector 2

Bulevardul Lacul

Tei, Nr. 1-3

2009 4x30

4x127

FA

+4x33

gypsum

4x190

Romelectro, Romania

Craiova-II Power Plant 2X150 MWe,

Romania

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, ,

Sector 2

Bulevardul Lacul

Tei, Nr. 1-3

2009 4x7

4x55.2

FA

+4x20

gypsum

4x82.2



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.



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.)


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.



GEA EGI Power & Process Technology

Ash silo



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


Ash silo

CIRCUMIX

mixers

Head and tank

recirculation

pumps

Platforms

Rotary ash

feeders


Ash silo

CIRCUMIX

mixers

Head and tank

recirculation

pumps

Platforms

Rotary ash

feeders

Head

recirculation

pipelines


Ash silo

CIRCUMIX

mixers

Head and tank

recirculation

pumps

Platforms

Rotary ash

feeders

Head

recirculation

pipelines

Tank

recirculation

pipelines


Ash silo

CIRCUMIX

mixers

Head and tank

recirculation

pumps

Platforms

Rotary ash

feeders

Head

recirculation

pipelines

Tank

recirculation

pipelines

Make up water

Documents

Circumix Dense Slurry Technology