View
228
Download
0
Category
Preview:
Citation preview
© EUtech Scientific Engineering GmbH Dennewartstrasse 25-27, 52068 Aachen, Germany www.eutech-scientific.de Phone:+49/241/963-2380 Fax:+49/241/963-2389
Co-Firing Optimization with Continuous Coal Flow Measurement
Dr.-Ing. Francesco Turoni
POWER-GEN Europe Köln June 13th, 2012
© EUtech Scientific Engineering GmbH Dennewartstrasse 25-27, 52068 Aachen, Germany www.eutech-scientific.de Phone:+49/241/963-2380 Fax:+49/241/963-2389
Introduction
Combustion optimization
EUcoalflow System
Applications and results
Summary
Contents
© EUtech Scientific Engineering GmbH Dennewartstrasse 25-27, 52068 Aachen, Germany www.eutech-scientific.de Phone:+49/241/963-2380 Fax:+49/241/963-2389
Introduction
© EUtech Scientific Engineering GmbH Dennewartstrasse 25-27, 52068 Aachen, Germany www.eutech-scientific.de Phone:+49/241/963-2380 Fax:+49/241/963-2389
Introduction
650 MW coal fired boiler with SCR (biomass co-firing)
High und local CO concentrations
Unbalanced coal flow distribution (coal flow hanks)
Coal flow not directly monitored and controlled
System information and ‘status quo’
High excess oxygen levels
Trade off between emissions and efficiency
© EUtech Scientific Engineering GmbH Dennewartstrasse 25-27, 52068 Aachen, Germany www.eutech-scientific.de Phone:+49/241/963-2380 Fax:+49/241/963-2389
Reduce process variability and shift operating point closer to the limits
Individual adjustment of air and fuel flow at burner level
Identify and utilize the intricate interplay of combustion parameters
Air/fuel ratio and performance Strategy
Introduction
l
hth
NOx
COLoI
l = 1.0 l
hth
NOx
COLoI
l = 1.0
lgeslopt
Air/fuel ratio (l) - optimised combustion settings
Air/fuel ratio (l) - regular combustion settings
System optimization
Adaptation to load changes
© EUtech Scientific Engineering GmbH Dennewartstrasse 25-27, 52068 Aachen, Germany www.eutech-scientific.de Phone:+49/241/963-2380 Fax:+49/241/963-2389
Why is coal and air flow control so important?
Controllable O&M variable Dh th
Coal fineness 0.1 - 0.3%
Primary air-flow 0.1 - 0.2%
Fuel line balance 0.1 - 0.3%
Particulate-air ratio 0.1 - 0.3%
Carbon-in-ash (LoI) 0.1 - 0.3%
Excess oxygen 0.1 - 0.3%
Total* 0.6 – 1.7%
* These benefits do not add up synergistically. Typically, an overall improvement in net efficiency will be around 0.3 – 1.0%
© EUtech Scientific Engineering GmbH Dennewartstrasse 25-27, 52068 Aachen, Germany www.eutech-scientific.de Phone:+49/241/963-2380 Fax:+49/241/963-2389
Combustion optimization
© EUtech Scientific Engineering GmbH Dennewartstrasse 25-27, 52068 Aachen, Germany www.eutech-scientific.de Phone:+49/241/963-2380 Fax:+49/241/963-2389
Combustion optimization
Measure
If you can´t measure, you can´t control.
Basic Idea
EUcoalflow sensors
EUcontrol Coalflow
Coal flow & primary air
© EUtech Scientific Engineering GmbH Dennewartstrasse 25-27, 52068 Aachen, Germany www.eutech-scientific.de Phone:+49/241/963-2380 Fax:+49/241/963-2389
Combustion optimization
Measure
If you can´t measure, you can´t control.
Control If you can´t control, you can´t optimize.
Basic Idea
EUcoalflow sensors
Orificing valve
EUcontrol Coalflow
Coal flow & primary air
© EUtech Scientific Engineering GmbH Dennewartstrasse 25-27, 52068 Aachen, Germany www.eutech-scientific.de Phone:+49/241/963-2380 Fax:+49/241/963-2389
Combustion optimization
Measure
If you can´t measure, you can´t control.
Control If you can´t control, you can´t optimize.
Optimize
If you don´t optimize, you waste money.
Basic Idea
Sec. air damper
Burner
EUcoalflow sensors
Orificing valve
EUcontrol Coalflow
Coal flow & primary air
Wind box
© EUtech Scientific Engineering GmbH Dennewartstrasse 25-27, 52068 Aachen, Germany www.eutech-scientific.de Phone:+49/241/963-2380 Fax:+49/241/963-2389
Combustion optimization
EUcoalflow Sensor
Coal mass flow 2 – 3 Sensors per pipe
Orificing valve Basic adjustment Pipe-to-pipe balancing Manual or motor driven
SA-Damper Control
Automatic adjustment of SA AFR at prescribed level
Basic Idea
Sec. air damper
Burner
EUcoalflow sensors
Orificing valve
EUcontrol Coalflow
Coal flow & primary air
Wind box
© EUtech Scientific Engineering GmbH Dennewartstrasse 25-27, 52068 Aachen, Germany www.eutech-scientific.de Phone:+49/241/963-2380 Fax:+49/241/963-2389
Mill upgradation
Coal dampers after classifier
Online coal flow measurement in each pipe
Adjust coal flows to acceptable reference limits (manual) Use excess O2 as global control variable
Optimize (emissions, heat rate, LoI, slagging, ...)
Applied actions and strategy
Combustion optimization
© EUtech Scientific Engineering GmbH Dennewartstrasse 25-27, 52068 Aachen, Germany www.eutech-scientific.de Phone:+49/241/963-2380 Fax:+49/241/963-2389
EUcoalflow system
© EUtech Scientific Engineering GmbH Dennewartstrasse 25-27, 52068 Aachen, Germany www.eutech-scientific.de Phone:+49/241/963-2380 Fax:+49/241/963-2389
Sensor type Microwave
Operating temp. < 200 °C
Flow density < 1000 g/m³
Sensor diameter 20 mm
Power supply 110/240 V AC
Sensor set-up 2 to 5 per pipe
Sensor
System specification
Data acquisition
Online determination of - Coal mass flow - Pipe-to-pipe distribution
Sensor & system calibration
Statistic functions
Features
System set-up
Sensor Control Unit
© EUtech Scientific Engineering GmbH Dennewartstrasse 25-27, 52068 Aachen, Germany www.eutech-scientific.de Phone:+49/241/963-2380 Fax:+49/241/963-2389
Mobile ECF System
Easy and quick set-up
- Quick release connector
- Purge air adapter
Comfortable control through ECF Software
Stand-alone operation and data acquisition (without PC)
Interface to DCS
Features
EUcoalflow system
Design
© EUtech Scientific Engineering GmbH Dennewartstrasse 25-27, 52068 Aachen, Germany www.eutech-scientific.de Phone:+49/241/963-2380 Fax:+49/241/963-2389
Installation and set-up
EUcoalflow system
© EUtech Scientific Engineering GmbH Dennewartstrasse 25-27, 52068 Aachen, Germany www.eutech-scientific.de Phone:+49/241/963-2380 Fax:+49/241/963-2389
EUcoalflow specification
Measurement principle
P0 = Power of reflected microwave
Caption
P(t
) Pow
er
t1 t2 t3 t (Time)
Mass flow:
m = f (P0,t) Microwave field Coal pipe
Particle Reflecting microwave
EUcoalflow sensor
P0
t1 t2 t3 t (Time)
|P(t
)/dt|
a
P(t)= a*t P(t)= -a*t +P1
t1/2 t2/2 t3/2
t1/2 t2/2 t3/2
P(t)= 2a*t
P0
P(t)= -2a*t +P1 P(t
) Pow
er
|P
(t)/
dt|
t (Time)
t (Time)
2a
© EUtech Scientific Engineering GmbH Dennewartstrasse 25-27, 52068 Aachen, Germany www.eutech-scientific.de Phone:+49/241/963-2380 Fax:+49/241/963-2389
Applications and results
© EUtech Scientific Engineering GmbH Dennewartstrasse 25-27, 52068 Aachen, Germany www.eutech-scientific.de Phone:+49/241/963-2380 Fax:+49/241/963-2389
Tests during load change
- High correlation with belt weigher data
- Online monitoring of inline balance in each burner pipe
High resolution signals
System results
High sensitivity
Conclusion
© EUtech Scientific Engineering GmbH Dennewartstrasse 25-27, 52068 Aachen, Germany www.eutech-scientific.de Phone:+49/241/963-2380 Fax:+49/241/963-2389
High fluctuation in the mass flow signal causes
fluctuating excess oxygen
(DCS signal) at constant load set point
High correlation of excess oxygen signal with fuel flow (biomass)
Direct visualisation of feeding and milling malfunctions
Control of secondary air flow
Immediate results Signal analysis
Conclusion
0
4
8
12
16
20
30
40
50
60
70
80
12
:00
12
:05
12
:10
12
:15
12
:20
12
:25
O2
Co
nce
ntr
atio
n [
%]
EUco
alfl
ow
mas
s fl
ow
[%
]
Time [hh:mm]
O2 Concentration EUcoalflow
System results
© EUtech Scientific Engineering GmbH Dennewartstrasse 25-27, 52068 Aachen, Germany www.eutech-scientific.de Phone:+49/241/963-2380 Fax:+49/241/963-2389
Tests with three mill settings
- Stable and reproducible signal
- Direct monitoring of load changes in each burner pipe
- Good correlation between EUcoalflow mass flow signal and mill load Linear fit can be used for signal calibration
y = 1,073.4x + 310.3
700
750
800
850
900
950
1000
1050
1100
40%
45%
50%
55%
60%
65%
70%
EUcoalflow raw signal Linear fit for calibration
0
200
400
600
800
1000
1200
1400
1600
0
100
200
300
400
500
600
700
800
11:3
0
11:4
0
11:5
0
12:0
0
12:1
0
12:2
0
12:3
0
12:4
0
12:5
0
13:0
0
13:1
0
13:2
0
13:3
0
13:4
0
13:5
0
14:0
0
14:1
0
14:2
0
14:3
0
Mean Burner 1 Mean Burner 2 Mean Burner 3 Mean Mill
System Results
Strong linearity Signal correlation
Load 45%
Load 55%
Load 65%
Conclusion Mill load
EU
coalflo
w
mean t
ota
l si
gnal
EU
coalflo
w s
ignal fo
r burn
er
1-3
© EUtech Scientific Engineering GmbH Dennewartstrasse 25-27, 52068 Aachen, Germany www.eutech-scientific.de Phone:+49/241/963-2380 Fax:+49/241/963-2389
Independent assessment of system upgradation
True system optimization
- Online monitoring and tuning of inline balance in each burner pipe
Efficiency improvement without emission worsening
System results
Application with co-firing
Conclusion
Clean combustion
-100% -75% -50% -25% 0% 25%
Increased efficiency
-45% -15% 10% 40%
before optimization after optimization
© EUtech Scientific Engineering GmbH Dennewartstrasse 25-27, 52068 Aachen, Germany www.eutech-scientific.de Phone:+49/241/963-2380 Fax:+49/241/963-2389
Active measurement and balancing of coal flow in all pipes
Real-time control of air-fuel ratios at burner levels
On-line monitor and supervision of mill operation
Improved combustion efficiency and emissions
- Improved efficiency (0.3 to 1%)
- Less NOx and CO emissions (-5 to -15 %)
- Less LOI
Less slagging and less cleaning demand
Positive effects on availability and maintenance
- Less down time
- Less boiler wall corrosion
Continuous profit through online measurement
Benefits
Recommended