Advances in Grate Combustion Technology fouling mitigation ... ACC loss ca. 50 ......

Advances in Grate Combustion Technology

WTERT 2012 Conference, Columbia University, October 18

2 WTERT 2012, Columbia University New York, October 18th

R&D Director’s Dream

New CCS • Upgrade of basic control module

• Add-on control features: Burn-out and fire end control (Riverside)

• Maximized throughput

Low Excess Air • Combustion with less combustion air

• Lower investment costs of new plants

• Improved energy efficiency

• Reduced emissions

Emissions ....

Boiler fouling mitigation • Longer campaign times for boilers

• Improved margins on new projects

• Improved guarantees; reduced guarantee costs

Inova Grate • Optimized grate construction, lower cost

• Lower maintenance costs

• Reduced building height

Additives ......

Bottom Ash Residue ....

Filter Residues ....

Dream: Show Case Project

Show the results of all ideas, development, modelling, trials and testing in a real plant

Fabric Filter ....

DyNOR®

• SNCR for low NOx emissions without catalyst

• <100 mg/m3 NOx with < 10 mg/m3 NH3 slip

3

1) Inova Grate

Features of the Inova Grate

Combines all positive aspects from cumulated years of experience

In particular the Inova Grate is built to:

Accommodate a wide range of fuels various configurations air and water cooled more grate movement controls

Further reduce burnout

Reduce plant building height (compared to Von Roll grate) less inclination

Minimize investment costs lower weight, fewer parts

Reduce maintenance costs easy access

Improve plant availability less and shorter outages

WTERT 2012, Columbia University New York, October 18th

4

2) New Generation Combustion Control System (CCS)

FT

QT O2

Steam

FC

FC

Recirculated flue gas

Secondary air

Flue gas

Primary air

FC

Ramfeeder /

Grate

control system

A04

Base value calculationBased on plant design

Primary air

Primary air temperature

Recirculated flue gas

Secondary air

Ram feeder speed

Grate speed

A03

A02

A01

TC

Operator

Adaptation

SetpointSteam production

A04

A03

A02

A01

Base CCS

PID-Controllers

Implemented on the DCS

Steam controller

O2 Controller

Combustion automatic

P

L

PT

Q

Q

T

T

P

PP

Supplementary controller

Fire position control

Burn – out control

Fuzzy-Hybrid Steam controller

Automatic heating value correction

...

...


5

2) New Generation CCS Features

Early Detection of

Fuel Property Changes

P

V1,m1

V2,m2

V3,m3

V4,m4

V5,m5

V6,m6

V7,m7,ζ7

P

s

Müllmasse [kg]

Müllvolumen [m3]

Stösseldruck [bar]

Stösselweg [mm]

∆P

F

Druckdifferenz [mbar]

Primärluftvolumenstrom [m3/h i.N.]

Kompakte Müllfraktion

Lockere Müllfraktion

ζ =

2 ∆P A2

ρ V2

.

Use existing or new

data to calculate feed

properties

0-1400 °C

0-100 %

350 – 550 nm

Feuerstart Feuerende

Temperaturverlauf Feuerstart zu früh

Temperaturverlauf ideal

UV Strahlungsintensität zu langes Feuer

UV Strahlungsintensität ideal

Fire Start Fire End

ideal positions

Ideal temperature

distribution on grate

Early fire start

Late fire start

Fire Position Control

Burnout Control

Reduce Load Drops

Determine reason for

Load Drop

Komp.

Dichte

Temp.

Zeta

Komp.

Dichte

Temp.

Zeta

Frischdampfleistung [t/h]

A) Zu wenig Brennstoff B) Schlechter Brennstoff

Richtige Massnahme A Richtige Massnahme B

Live steam flow

Low fuel Bad fuel

Variable

setting A Variable

setting B


6

2) New Generation CCS Benefits

Sample calculation 2 x 500 tpd - 19 days:

Steam production: 55‘842 tons

Lost steam production: 2526 tons

Extrapolated to whole year (330 days):

Lost steam production: 43‘873 tons

Lost electric production: 7239 MWh/y

Lost $ ($80/MWh): 579‘119 $/y

Typical Steam Production Trend

with conventional/basic CCS

Typical Steam Production Trend with New Generation CCS


7

3) Boiler Efficiency Analysis and Intelligent Boiler Cleaning

Shower cleaning

Explosion cleaning

Automated and monitored pneumatic

rappers:

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

1.4

.08

1.5

.08

1.6

.08

1.7

.08

1.8

.08

1.9

.08

1.1

0.0

81

.11

.08

1.1

2.0

81

.1.0

91

.2.0

91

.3.0

91

.4.0

9

Eff

izie

nz (

%)

0

2

4

6

8

10

12

14

16

18

20

Dru

ckab

fall

Rau

chg

as K

esse

l (m

bar

)

ÜH3 ÜH2 ÜH1 ECO dP RG

Bo

ile

r S

ec

tio

n E

ffic

ien

cie

s

Bo

ile

r F

lue

Ga

s H

ea

d L

oss

[m

ba

r]

Scaling almost instantly reduces

boiler efficiency

Efficiencies are calculated for

individual boiler sections

cleaning efforts are optimized

1 year period


8

4) DyNOR® - Dynamic NOx Reduction

DyNOR®

Flow

Distributors

Injection Level

IR Pyrometers

Virtual segmentation of the boiler

Quick temperature measurement

Dynamic, precise and quick

responding reagent injection


9

4) DyNOR® performance (before other measures)

0

20

40

60

80

100

120

140

160

180

18:

00

0:0

0

6:0

0

12:

00

18:

00

0:0

0

6:0

0

12:

00

NO

x (m

g/m

3 s

tp d

ry 1

1%

O2)

0

10

20

30

40

50

60

70

80

90

NH

3 (

mg

/m3 s

tp d

ry 1

1%

O2)

NOx-setpoint:

100mg/m3

DyNORTM

NOx-setpoint:

68 ppmv @7% O2

Results have been confirmed in

other plants:

Client: Westenergy OY

Location: Vaasa, Finland

Capacity: 1 x 520 tpd

61 MWth

Start-up: 2012


London, UK

Thermal Input Waste

(100 %)

ACC loss

ca. 50 – 55 %

Stack loss

ca. 10 – 15 %

Slag loss

ca. 2 %Various

ca. 2 – 4 %

Net Electricity

ca. 25 %ca. 25 – 30%

10

5) Energy Efficiency Improvement: minimize losses

Sta

ck

AC

C

Slag

Stack losses are significant

Roughly 10 – 15% of energy (LHV basis)

Efficiency improvement by …

…lowering exhaust gas temperature

…lowering exhaust gas flow rate

Electricity


11

5) Energy Efficiency: after lot of modelling

DEM Model (Discrete Elements Method)

(in cooperation with LEAT / U of Bochum)

Objective:

Numerical model of movement on grate

and thermochemical processes within

particles and gas phase

Method:

coupling of various modelling modules to

account for:

solid mechanics/ particle movement

drying/gasification/pyrolysis of

particles

heat transfer to/within particles

gas flow pattern and burn-out of gases

radiant heat transfer

Schnittstelle für

den Austausch

Interface surface for

data exchange to

the CFD model

Example:

content of volatiles

in solid particles


12

5) Energy Efficiency: ..and even more modelling

end of flame zone

Results:

Good agreement of modelled

and measured temperature and

oxygen profiles

Identification of two extreme gas

conditions:

Feed end

oxygen: 0 –10 %

CO: 5 – 20 %

(varies greatly in time)

hydrogen: 2 – 5 %

Discharge end

oxygen: 20 %


13

5) Energy Efficiency: the Solution

0 20 110 130 150 170 190 2000

1

2

3

4

5

6 //

//

//

O2 [

vo

l%w

et]

0 20 110 130 150 170 190 200

100

10000

100000

1000

10

//

//

time [min.]

CO

loca

l [m

g/m

3 a

t S

TP

]

O2, global

O2, local

RFG ON RFG OFF RFG ON RFGOFF

New Patented Premixing

Solution

With premixing on…

local O2 = O2 at stack

local CO homogeneous

and low

Flue gas flow

20% lower ( < 1.20)

Expected electricity prod.

4% higher

ON = well mixed

(O2, local = O2, global) OFF = not fully mixed

(O2, local ≠ O2, global)

Conc.

COlocal up to 100x


14

5) NOx generation

0

100

200

300

400

500

600

0 5 10 15

O2 concentration boiler (vol % dry)

NO

x c

onc. (m

g/m

3 i.N

. 11%

O2 d

ry) Germany 2004

Norway 1999

Germany 1998

Switzerland 2002

Switzerland 1990

Netherlands 2004

Netherlands 1996

Switzerland 2003

Germany 2005

Germany 2005

Norway 2007

Switzerland 2010

without flue gas

recirculation

with flue gas

recirculation

Lausanne

NOx, uncontrolled, 1-minute averages

0

68

136

204

272

340

408

NO

x c

onc.

(pp

mv

@ 7

% O

2 dr

y)


And R&D Director’s Dream Came True: RENERGIA

Location: Perlen, near

Lucerne, Switzerland

Capacity: 2 x 410 tpd

2 x 47 MWth

Contract: 04/2012

Start-up: 01/2015

Many of the above

described new

developments will be

included in this plant

15 WTERT 2012, Columbia University New York, October 18th

16

Thank you for your attention

Peter Chromec

Hitachi Zosen Inova U.S.A. LLC

3740 Davinci Court, Suite 250

Norcross, GA 30092

T: +1 678 987 2501

[email protected]


Advances in Grate Combustion Technology fouling mitigation ... ACC loss ca. 50 ......

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Transcript of Advances in Grate Combustion Technology fouling mitigation ... ACC loss ca. 50 ......