Everyone wants the highest efficiency, but on-site condition and environmental permits are often contrary for optimal efficiency. Knowledge of current and pending regulations can make or break a project. Dropping emissions limits (in some areas of the country, approaching 5 ppm total NOx) have been the driving factor in improving combustion control while still improving system efficiency. Accurate emissions measurements are critical during commissioning and maintenance.
Ensuring boiler & burner efficiency
The Challenge
When evaluating the burner’s characteristics, the focus of attention is on fuel, and air delivery, flame behavior, and of course the measured flue gas and emissions values.
Experienced service engineers also know that other combustion systems need to be checked:
- Optimized fuel density and delivery and air supply is crucial in order to maintain a wide operating range, stable flame, and the best efficiency with lowest emissions.
- Correct set-points must be confirmed. Ensure that fan capacity, the blowers and air ducts are controlled and coordinated with one another. These items combined with well-designed furnace dimension, burner spacing, and wind-box, all contribute to better controlled combustion.
- Your tools and combustion analyzer need to work correctly all the time. You want to be certain the installation is operating correctly.
When analyzing the burner’s behaviour, the focus of attention is often on fuel supply, atomization, control behaviour and emissions values. However, experienced service engineers know: optimum air supply is crucial for a wide adjustment range, stable combustion and the best emissions values. This means it is vital to ensure that blowers, air ducts and controls are coordinated with one another.
There is therefore an optimum fuel to air supply ratio for every combustion process. The combustion plant operates with a stable flame, optimum efficiency and lowest emissions in this range. The challenge for service engineers lies in determining the optimum air ratio and setting the system on that basis.
The details of how the differences in terms of the fuel-air mixture can be best set vary according to the boiler manufacturer, type of fuel and control plan. Some burners control the quantity of air which is taken into the boiler, others the quantity of fuel and still more allow the setting of both parameters. In any case, it is important to know the exact oxygen content in the process to ensure reliable and cost-effective operation.
There is therefore an optimum fuel to air supply ratio for every combustion process. The combustion plant operates with a stable flame, optimum efficiency and lowest emissions in this range. The challenge for service engineers lies in determining the optimum air ratio and setting the system on that basis.
The details of how the differences in terms of the fuel-air mixture can be best set vary according to the boiler manufacturer, type of fuel and control plan. Some burners control the quantity of air which is taken into the boiler, others the quantity of fuel and still more allow the setting of both parameters. In any case, it is important to know the exact oxygen content in the process to ensure reliable and cost-effective operation.
White paper
Power generation, the heating of buildings or cement and glass manufacture – burner and boiler systems provide the necessary thermal energy. And to ensure the combustion process runs in the most cost-effective and environmentally friendly way possible, service engineers have to trim the system perfectly. You will find all the relevant topics involving flue gas analysis and system trimming in our new white paper:
- The chemical reactions during combustion
- The influence of the fuel-air ratio on efficiency and emissions
- The optimum setting of the system with the testo 340 and testo 350
The two solutions – testo 340 or testo 350 for combustion tuning
The testo 340 and 350 analyzers show you the measurements that allow you to make control adjustments. Use them to measure the O2 or excess air for proper fuel setup in commercial and industrial systems. Use them to find inbound air leakage in gaskets or between pollution control devices. The analyzers pressure sensors allow you to check air flow, chimney draft, or differential room pressure to maximize performance. Use the testo 340 to establish the best combustion conditions. Use the testo 350 when a critical NOx permit must be met or when additional measurement parameters are needed.
easyEmission software - When connected to your computer, easyEmissions software allows you to operate the analyzer and log the values directly into a computer. Display the measurements as a simple table or graph, or expand the view to see values from the other side of the boiler room. It allows for fast direct downloading into Excel so you can transfer the data into your own report, or use the software’s standard report templates. When testing for State or Federal compliance use TECsoft software with the 350, for an easy way to generate reports.
Application sketch
Here you can download the most important information about the application involving boilers now:
- Emissions development (Lambda)
- Optimum boiler settings
Efficient service measurements
with the testo 340
- Four (4) gas flexibility. Rugged constriction inside and out. Always ready to perform under the harshest conditions.
- Long life-time CO and NOx sensors (up to 5 years) make cost of ownership the best in market. Field exchangeable sensors allow greater flexibility, including low and ultra low NOx applications.
- The automatic dilution (range extender) factor-5x increases the CO range to 50,000 ppm. The analyzer will calculate and display the corrected values. User defined setpoints means you can extend the CO sensor life and maintain accurate measurements.
- The bright back-lit display shows measurements, efficiency, excess air calculations, as well as corrected NOx and CO values. The display parameters are easily customizeable, can display from 4 to 8 lines, or show a variety of measurement options, such as PPM values or as MMBtu/hr.
- Quick-connect 9 foot hose extensions (maximum 2) with integrated thermocouple means you can extend the hose to 25 feet. Simply disconnect them for easier, less bulky transport.
High-precision emissions measurements with the testo 350
- Test up to six gases. Convenient plug & play sensors allow fast field changes. Easily swap out and test low NOx applications one day, and commissioning and mapping the next.
- Comprehensive calculations (i.e NOx and CO corrected to 3%) make comparison to permit conditions easier.
- The 300-foot Bluetooth connection lets you see quick boiler output changes without measurement delays normally experienced with long sample lines.
- Advanced sample conditioning (Peltier chiller) removes moisture for high accuracy. Proven sample gas paths with Teflon® lined hoses have the fastest response times and maintain sample integrity.
- The automatic test programs save data and control the analyzer to eliminate sensor drift. It also allows for long-term un-attended testing capabilities than can last for hours, or weeks, and even more.
- The standard dilution system delivers the widest testing ranges and promotes longer sensor life. The upgraded system allows for CO to 400,000 ppm, and NO, NO2, SO2, H2S to 5 times the sensor range.
- Testo 350 complies with many state and federal protocols including: US EPA CTM-030, -034 and ASTM D6522 requirements.
