Boiler Tuning

Corrosion Management

Field Testing Services

Fuel Switching

Laboratory Services

Regulatory Consulting

Training

Press Releases

Air Heater Efficiency CleanAir has the experience and capabilities to conduct air heater efficiency testing in accordance with accepted industry protocols (ASME PTC 4.3). By determining the average inlet and outlet concentration of either flue gas excess oxygen (O2) or carbon dioxide (CO2), the air in-leakage into the system can be calculated. The temperature of the flue gas leaving the airheater (which is the final heat exchange element in the boiler) has a direct influence on the station efficiency. For example, a 70 ºF increase in this temperature could result in a 0.5% decrease in station efficiency. There are many causes of an increase in this temperature, all to do with reductions in energy absorbed from the hot gas in or after the furnace. The most usual problems are: fouling of the external heat transfer surfaces of the furnace, superheaters, reheaters and economizers - many of these surfaces have to be regularly cleaned using jets of steam. This "soot blowing" wastes the steam, so the extent of soot blowing is always a compromise between the reduction in efficiency caused by soot blowing and increase in efficiency resulting from cleaner heat transfer surfaces; fouling of the internal heat transfer surfaces of the furnace, superheaters, reheaters and economizers caused mainly by incorrect chemistry of the water and steam in these tubes; or by incorrect material selection of the tubes; or by the tube material overheating; or combinations of these; and fouling, corrosion/erosion and blocking of airheater elements. Back to Boiler Schematic Back to Top Ammonia Injection Grid Tuning A sound selective catalytic reduction (SCR) catalyst management program as well as the successful operation of an SCR system will include at a minimum annual ammonia injection grid (AIG) tuning to optimize the NH3:NOx distribution over the cross section of the catalyst bed, minimize ammonia slip and to reduce O&M costs.  CleanAir’s team of experienced engineers using our proprietary flue gas profiling system called the Multi-Point Automated Sampling System (MASS) has provided AIG tuning support to plant operators, engineers and catalyst management providers. Back to Boiler Schematic Back to Top Boiler and Combustion Efficiency CleanAir can conduct testing to document boiler efficiency utilizing industry accepted testing protocols (ASME Performance Test Codes), and we can also perform tests directed toward increasing (improving) boiler and combustion efficiency, thereby reducing unit operating costs. The CO and excess air (boiler O2) contents of the flue gas, the unburned carbon in the fly ash, and steam temperatures affect boiler efficiency, turbine net heat rate, and auxiliary power requirements, which in turn determine unit net heat rate. If the excess oxygen is set too high or too low, dry gas heat losses can be large or unburned carbon in ash can be excessive. This reduces unit thermal efficiency and can render the ash unsuitable for re-use. Back to Boiler Schematic Back to Top Coal Flow CleanAir has the capability of conducting coal pipe flow studies by use of Rotoprobe or "dirty pitot". Back to Boiler Schematic Back to Top Corrosion Monitoring CleanAir has partnered with Corrosion Management, Ltd. and Reaction Engineering International to perform both high temperature and low temperature corrosion investigation studies. Using electrochemical sensor instrumentation, corrosion behavior of heat transfer elements can be determined. The electrochemical module(s) is integrated into a computerized digital data acquisition system, which collects the data, correlates it with temperature data from the sensor and the gas stream, displays it and stores it for later evaluation. The data acquisition unit is typically interfaced to the plant control computer to enable corrosion data to be displayed alongside process parameters and to allow plant parameters to be trended alongside corrosion data for cause/effect evaluations. Back to Boiler Schematic Back to Top ESP Performance & Diagnostics CleanAir has conducted numerous electrostatic precipitator (ESP) performance test programs. These programs typically involve the measurement of particulate mass emission rates at the inlet and outlet of the ESP using EPA approved procedures. Diagnostic capabilities include "hot wire" studies to determine flow profiles, insitu resistivity determination, and particle size and characterization determination. Back to Boiler Schematic Back to Top FEGT Measurements CleanAir manufactures and utilizes high velocity thermocouple (HVT) probes to measure furnace exit gas temperatures (FEGT) and species concentrations. The probes have an integrated sampling tube that allows an analyzer to draw a gas sample from the furnace to analyze the gas (e.g. O2, CO, NOX). A water-cooled jacket protects and cools the probe, while quick connect couplings allows for fast and easy attachment of air and water to standard industrial connections. The water-cooled HVT probe can be used to map the furnace exit plane of a utility or industrial boiler. Once a traverse of the furnace has been completed, the results can be plotted in order to diagnose operational problems such as air in-leakage, secondary airflow and/or fuel imbalances. Back to Boiler Schematic Back to Top FGD Performance Another of CleanAir testing services is flue gas desulfurization (FGD) performance testing. CleanAir has conducted performance testing on both wet and dry scrubber systems. FGD performance testing involves a series of emission tests that typically includes measurement of the following parameters: sulfur dioxide (SO2) removal efficiency; particulate emissions (FGD inlet/outlet); electrical power consumption; gas properties; fuel properties; reagent properties; and make-up water properties. Back to Boiler Schematic Back to Top Flue Gas Analysis When conducting diagnostic or boiler performance testing, CleanAir will utilize a multi-probe gaseous sampling matrix at the economizer outlet. With knowledge of the boiler duct cross sectional area, a sampling grid is established that will provide a representative sample. Measurements are made of the combustion products (O2, CO2, CO, NO, SO2) in the flue gas stream. With knowledge of the distribution of O2, CO and NO, in the convective back pass, the field performance engineer can make discrete adjustments to burner damper settings, burner tilt control, excess air control bias, or mill bias control in order in order to optimize the combustion characteristics of the boiler. Back to Boiler Schematic Back to Top Flyash Resistivity and Particle Sizing CleanAir’s particle characterization laboratory provides flyash resistivity and particle size distribution analysis. A combination of this laboratory data and computer modeling is used to optimize the flyash collection efficiency of electrostatic precipitators and to predict the ESP performance over a wide range of flue gas conditions, such as varying temperatures and SO3 concentrations. The laboratory routinely performs the following: Coal-switching studies by evaluating the resistivity of select coals and blends to predict ESP collection performance Study the effect of flue gas conditioning to improve ESP collection Increase generating output of units derated due to opacity Back to Boiler Schematic Back to Top Fuel Switching CleanAir has the capability of conducting fuel switching studies for electric utility boilers. Fuel switching typically involves switching from a high sulfur to a low sulfur coal as part of an emission compliance strategy. But, to maintain plant efficiency and avoid a unit derate, all areas of your plant must be evaluated for the effects of the change in fuels: fuel delivery, coal receiving and handling, burners, air heaters, heat transfer surfaces, auxiliary power, precipitators, ash handling systems, and instrument, controls and electrical equipment. Back to Boiler Schematic Back to Top SCR Performance Testing CleanAir has worked with both utility boiler owners and selective catalytic reduction (SCR) system vendors on several SCR installation projects to characterize SCR system performance. As part of a typical SCR performance test program, the NOx removal efficiency, inlet and outlet NOx distribution, inlet temperature and velocity distribution, ammonia (NH3) slip, SO2 to SO3 conversion, SCR and catalyst pressure drop are determined to demonstrate compliance with SCR performance guarantees. Back to Boiler Schematic Back to Top SNCR Performance Testing CleanAir has conducted several selective non-catalytic reduction (SNCR) performance evaluation test programs. These programs are generally directed toward establishing NOx removal efficiency, ammonia slip, airheater pressure drop, and furnace exit gas temperature profiles. Back to Boiler Schematic Back to Top Unburned Carbon CleanAir uses EPA approved test procedures to isokinetically extract fly ash samples from the flue gas stream in order quantify the amount of unburned carbon in the ash. Elevated unburned carbon levels are an indication of incomplete combustion, and represent an efficiency loss. Very high unburned carbon in the ash, presents the potential for safety concerns such as airheater and/or ESP fires. CleanAir utilizes unburned carbon testing in combination with flue gas analysis to optimize unit performance. Back to Boiler Schematic Back to Top