Has combustion automation changed much since the advent of the distributed control system (DCS)? When automobile technology transitioned from carburetors to fuel injection, it brought a new standard of safe, reliable, clean, efficient performance. However, other than widespread adoption of NFPA codes, operation of fired assets such as heaters, furnaces, ethane crackers, and steam methane reformers really hasn’t changed much in decades. Imprecise, inaccurate, and often corrupted process data conspires to leave operators with sloppy control loops and ambiguities, which lead to questions such as:
• Do I really know that my purge is complete?
• What are my ideal set points?
• Can I truly trust the data on my screen?
• How close to ideal can I safely run?
• How do I know when I’m operating dangerously?
• When I get in trouble, is a trip my only recourse?
These uncertainties can produce inconsistent decisions and, in turn, unnecessary fuel consumption, non-optimal process throughput, excessive emissions, accelerated aging of assets, increased maintenance, and, most importantly, safety compromises.
It doesn’t have to be like this; there’s a better way to combust. With its initial founding derived from the recommendations of IEC 556, Yokogawa has re-drawn the limits of safe, efficient, clean combustion. Through the proven path of CombustionONE, Yokogawa welcomes all fired asset operators to explore beyond the "Flat Earth Era" of combustion automation.
Optimizing Combustion - Transcending the "Flat Earth Era"
1. Richard Bosse
North America Sales & Marketing Lead:
CombustionONE
Yokogawa
Optimizing Combustion -
Transcending the
‘Flat Earth Era’
November 11, 2020
2. When on ‘Flat Earth’,
keep a safe distance from the edge
8. …just adds to an already long list of concerns
…and…
…balancedwith…
…and…
…yetalways….
EXTENDING
THE LIFE OF
FIRED ASSETS
(AND CATALYSTS
IF APPLICABLE)
SAFETY
• Avoid burner flame out, but rapid
response when it happens
• Eliminate accumulated combustibles
• Reduce trips/increase stability
• Optimize time spent in process area
• Decrease tube failures
EFFICIENCY
• Reduce fuel consumption
• Optimize excess air
• Minimize tramp air
• Retain experience of
aging/retiring operators
• Reduce flaring
• Stabilize O2
and coil outlet
temperature swing
EMISSIONS
• Reduce CO2
greenhouse
gases
• Reduce other emission that
may be limiting production
(NOx & CO)
THROUGHPUT
• Maximize heat capacity
• Tube temp limitations
• Reduce coking & fouling
• Shorten start ups
• Increase production rates
• Decrease T/A frequency
Com
bustionO
NE
START
HERE
9. The CombustionONE Core Solution
1. Real-time LHV calculations
2. Burner balancing
3. Fast, accurate O2, CO, and CH4
measurements
4. Precise wind compensated draft
measurements
5. CLOSED LOOP Combustion
controls utilizing dynamic A/F
ratio control with CO/O2 cross
limited supervisory optimization
Safety bonus – real time CH4 used
as a BMS startup permissive
1
2
3
4
5
Simple to operate & support
Comprehensive
Agnostic
Proven
10. CombustionONE Turnkey to Address API 556 & More
Measurement improvements
• Instruments (burner balancing, fuel density and
flow, stack flow)
• Wind compensation ring for stabilized stack flow
• O2, CO, CH4, NH3 TDLS analyzer
• CEMS
• Engineering/Installation services
Controls improvements
• Advanced combustion controls
• Improved burner management
• Updated graphics & historian
• Reports
• Engineering/Installation services
11. CombustionONE Turnkey to Address API 556 & More
Other complementary improvements
• Feedwater pH optimization
• Ammonia slip optimization
• Combustion optics
• Turbomachinery controls
• Plant master & energy optimization
• Startup/shutdown procedural automation
• Operator training simulators
• Digital twins
• Full plant performance improvement analytics,
before or after implementation
• Remote diagnostics via secure cloud
12. Safety Benefit #1 – Eliminate Hazardous Zirconium Oxide
Pictures from Dow’s publication on the hazards of Zirconium Oxide probes
as a potential ignition source (operating temp > CH4 combustion point)
“BEFORE”
Heater Offline…With Gas Valve Leak
“AFTER”
Gas Leak Found The Zirconium Oxide Probe
13. Safety Inherent To The TDLS Technology
▪ In-Situ
▪ N2 or Instrument Air Cooling & Glass Cleaning
Sensor
Control Unit
Laser
Unit
Mounting
Flange
Gas Flow
O2
O2
O2
O2
O2
O2
▪ Interference Free
▪ Safely non-contacting
16. Safety Benefit #4 – CO Visibility to Prevent Afterburning
Afterburning? Where Is Combustion Occurring???
17. Safety Benefit #5 - Fast & Accurate Air & Fuel Control Loops
Fast & accurate measurements
of fuel heat value and flue gas
composition before and after
combustion allow safer
combustion control
18. Improved Fuel Efficiency & Production Capacity
API 556 Section 3.4.4.9.2
“F) in a properly designed system
with fast response infrared or lased
based O₂/CO measurements,
oxygen control at less than 1% may
be acceptable”.
19. Balancing Safety, Efficiency, Throughput, Emissions, & Assets
UNSAFE
CO “VIOLATIONS”
CO2
EXCURSIONS
EFFICIENCY LOSSES
EFFICIENCY LOSSES
NOx “VIOLATIONS”
% EXCESS AIR
-20 -10 0 10 20
CO &
Combustibles
NOx
O2
Ideal
Decreases
Decreases
FUEL RICH AIR RICH
Fuel & CO2
Decreases
Production
Increases
20. Air/Fuel Ratio Must Account For Air & Fuel Variability
Calculated A/F Ratio
26
25
24
23
22
20
21
19
18
17
21. The Results Of Poor, Slow Measurements & Inaccurate Control
Instability and Inefficiency
22. The Results Of Poor, Slow Measurements & Inaccurate Control
Instability and Inefficiency
24. Extended Asset Life
Stabilized Operation Is Easier On Your Fired Assets
Burner balancing & decreased draft – reduces hotspots, extending tube life
(also reduces tramp air and increases residence time)
Stabilized COT, O2
, & operation
1. Reduces thermal cycling stress of tubes, hangers, etc.
2. Quickly responds to feed pressure variations, avoiding trips.
3. Makes the process easier to manage, so fewer trips. Avoiding severe thermal cycling from
trips extends asset life.
4. Minimizes COT temperature peaks, benefitting coking/fouling.
25. Benefits Bottom Line
• Unlike a ZrOx probe, the TDLS is not an ignition source (API 556 recommendation)
• Methane measurement can be used as a BMS start-up permissive
• Much faster & more accurate measurements & control loops, so more capable operators
SAFETY
• Operator freedom to safely run closer to the CO breakthrough, with CO override of O2
• Dynamic A/F ratio while using existing combustion control logic
• Stabilized COT = fewer trips
• Less tramp air, reduced afterburning in convection section
FUEL EFFICIENCY/PRODUCTION THROUGHPUT
• Hotspots reduced by burner balancing
• Faster & more accurate loops maximize response, minimizing trips
ASSET LIFESPAN
• Lower O2
means lower NOx and lower CO2
EMISSIONS