Effect of Volatiles on Soot Based Deposit Layers

2013 ◽  
Author(s):  
Ashwin Salvi ◽  
John Hoard ◽  
Mitchell Bieniek ◽  
Mehdi Abarham ◽  
Dan Styles ◽  
...  
Keyword(s):  
Heat Exchangers ◽  
Nox Reduction ◽  
Infrared Camera ◽  
Optical Microscope ◽  
Exhaust Gas ◽  
Thermogravimetric Analyzer ◽  
Gas Recirculation ◽  
Thermo Physical Properties ◽  
Deposit Layer

The implementation of exhaust gas recirculation (EGR) coolers has recently been a widespread methodology for engine in-cylinder NOX reduction. A common problem with the use of EGR coolers is the tendency for a deposit, or fouling layer to form through thermophoresis. These deposit layers consist of soot and volatiles and reduce the effectiveness of heat exchangers at decreasing exhaust gas outlet temperatures, subsequently increasing engine out NOX emission. This paper presents results from a novel visualization rig that allows for the development of a deposit layer while providing optical and infrared access. A 24-hour, 379 micron thick deposit layer was developed and characterized with an optical microscope, an infrared camera, and a thermogravimetric analyzer. The in-situ thermal conductivity of the deposit layer was calculated to be 0.047 W/mK. Volatiles from the layer were then evaporated off and the layer reanalyzed. Results suggest that volatile bake-out can significantly alter the thermo-physical properties of the deposit layer and hypotheses are presented as to how.

Effect of Volatiles on Soot Based Deposit Layers

2014 ◽  
Vol 136 (11) ◽  
Author(s):  
Ashwin Salvi ◽  
John Hoard ◽  
Mitchell Bieniek ◽  
Mehdi Abarham ◽  
Dan Styles ◽  
...  
Keyword(s):  
Heat Exchangers ◽  
Nox Reduction ◽  
Infrared Camera ◽  
Optical Microscope ◽  
Volatile Components ◽  
Exhaust Gas ◽  
Thermogravimetric Analyzer ◽  
Gas Recirculation ◽  
Deposit Layer

The implementation of exhaust gas recirculation (EGR) coolers has recently been a widespread methodology for engine in-cylinder NOx reduction. A common problem with the use of EGR coolers is the tendency for a deposit, or fouling layer to form through thermophoresis. These deposit layers consist of soot and volatiles and reduce the effectiveness of heat exchangers at decreasing exhaust gas outlet temperatures, subsequently increasing engine out NOx emission. This paper presents results from a novel visualization rig that allows for the development of a deposit layer while providing optical and infrared access. A 24 h, 379-micron-thick deposit layer was developed and characterized with an optical microscope, an infrared camera, and a thermogravimetric analyzer. The in situ thermal conductivity of the deposit layer was calculated to be 0.047 W/mK. Volatiles from the layer were then evaporated off and the layer reanalyzed. Results suggest that the removal of volatile components affect the thermophysical properties of the deposit. Hypotheses supporting these results are presented.

Visual Study of In-Situ EGR Cooler Fouling Layer Evolution

2014 ◽  
Author(s):  
Haochi Li ◽  
John Hoard ◽  
Daniel Styles ◽  
Ashwin Salvi ◽  
Akshay Kini ◽  
...  
Keyword(s):  
Heat Exchangers ◽  
Gas Flow ◽  
Nox Reduction ◽  
Time Lapse ◽  
Layer Growth ◽  
Future Emission ◽  
Egr Cooler ◽  
Gas Recirculation ◽  
Deposit Layer

Exhaust gas recirculation (EGR) is a major technology to reduce NOx from diesel engines for future emission standards. The implementation of EGR coolers has been a common methodology to provide engine in-cylinder NOx reduction. However, EGR cooler fouling is a common problem. The particulate matter in exhaust tends to form a deposit layer on the wall of the heat exchangers. This effect leads to a reduction of thermal effectiveness of the heat exchangers resulting in insufficient EGR cooling and subsequently higher engine NOx emission. This paper utilized a unique test rig offering visible and infrared optical access to the deposit layer in a simulated diesel EGR cooler to study the evolution of the layer from fresh to heavy deposit. A 460μm thick deposit layer was built during a 37 hour exposure. Time lapse videos were taken provide visual in-situ evidence for the investigation of the layer thickness development and morphology change during the deposition. The layer growth tended to stabilize from about 22 hours of deposition. The shear force exerted by the gas flow moves surface particles of 20μm in diameter or larger. This could contribute to the stabilization phenomenon.

NOx Emissions Modeling and Uncertainty From Exhaust-Gas-Diluted Flames

2015 ◽  
Vol 138 (5) ◽  
Author(s):  
Antonio C. A. Lipardi ◽  
Jeffrey M. Bergthorson ◽  
Gilles Bourque
Keyword(s):  
Nox Reduction ◽  
Flame Temperature ◽  
No Production ◽  
Exhaust Gas ◽  
Oxides Of Nitrogen ◽  
Nox Formation ◽  
Kinetic And Thermodynamic Parameters ◽  
Emissions Modeling ◽  
Combustion Processes ◽  
Gas Recirculation

Oxides of nitrogen (NOx) are pollutants emitted by combustion processes during power generation and transportation that are subject to increasingly stringent regulations due to their impact on human health and the environment. One NOx reduction technology being investigated for gas-turbine engines is exhaust-gas recirculation (EGR), either through external exhaust-gas recycling or staged combustion. In this study, the effects of different percentages of EGR on NOx production will be investigated for methane–air and propane–air flames at a selected adiabatic flame temperature of 1800 K. The variability and uncertainty of the results obtained by the gri-mech 3.0 (GRI), San-Diego 2005 (SD), and the CSE thermochemical mechanisms are assessed. It was found that key parameters associated with postflame NO emissions can vary up to 192% for peak CH values, 35% for thermal NO production rate, and 81% for flame speed, depending on the mechanism used for the simulation. A linear uncertainty analysis, including both kinetic and thermodynamic parameters, demonstrates that simulated postflame nitric oxide levels have uncertainties on the order of ±50–60%. The high variability of model predictions, and their relatively high associated uncertainties, motivates future experiments of NOx formation in exhaust-gas-diluted flames under engine-relevant conditions to improve and validate combustion and NOx design tools.

Exhaust Gas Recirculation Performance in Dry Low Emissions Combustors

2011 ◽  
Author(s):  
A. M. Elkady ◽  
A. R. Brand ◽  
C. L. Vandervort ◽  
A. T. Evulet
Keyword(s):  
Gas Turbine ◽  
Co2 Capture ◽  
Carbon Capture ◽  
Power Plants ◽  
Nox Reduction ◽  
Co2 Concentration ◽  
Exhaust Gas Recirculation ◽  
Exhaust Gas ◽  
Low Oxygen ◽  
Gas Recirculation

In a carbon constrained world there is a need for capturing and sequestering CO2. Post-combustion carbon capture via Exhaust Gas Recirculation (EGR) is considered a feasible means of reducing emission of CO2 from power plants. Exhaust Gas Recirculation is an enabling technology for increasing the CO2 concentration within the gas turbine cycle and allow the decrease of the size of the separation plant, which in turn will enable a significant reduction in CO2 capture cost. This paper describes the experimental work performed to better understand the risks of utilizing EGR in combustors employing dry low emissions (DLE) technologies. A rig was built for exploring the capability of premixers to operate in low O2 environment, and a series of experiments in a visually accessible test rig was performed at representative aeroderivative gas turbine pressures and temperatures. Experimental results include the effect of applying EGR on operability, efficiency and emissions performance under conditions of up to 40% EGR. Findings confirm the viability of EGR for enhanced CO2 capture; In addition, we confirm benefits of NOx reduction while complying with CO emissions in DLE combustors under low oxygen content oxidizer.

Application of an Experimental EGR System to a Medium Speed EMD Marine Engine

2009 ◽  
Author(s):  
John Hedrick ◽  
Steven G. Fritz ◽  
Ted Stewart
Keyword(s):  
Nox Reduction ◽  
Injection Timing ◽  
Exhaust Gas ◽  
Marine Engine ◽  
Air Temperatures ◽  
Medium Speed ◽  
Particulate Matter Emissions ◽  
Baseline Test ◽  
Exhaust Energy ◽  
Gas Recirculation

This paper focuses on quantifying emission reductions associated with various on-engine technologies applied to Electro-Motive Diesel two-cycle diesel engines, which are very popular in marine and locomotive applications in North America. This paper investigates the benefits of using exhaust gas recirculation (EGR), separate circuit aftercooler, and retarded injection timing on a EMD 12-645E7 marine engine. The EGR system alone provided up to a 32.9% reduction in brake specific Nitrogen Oxides (NOx) emissions while demonstrating less than one percent increase in cycle brake specific fuel consumption (BSFC). The brake specific particulate matter emissions increased somewhat, but at a modest rate based on the amount of NOx emission reduction. When the enhanced aftercooler system was combined with the addition of EGR, there was a 31.9% reduction in NOx and essentially no change to the BSFC when compared to the baseline test. The minimum manifold air temperature (MAT) was limited due to the size of the standard EMD aftercooler heat exchanger that is fitted on the engine. No efforts to modify the turbocharger to improve the turbo match to take advantage of the lower manifold air temperatures and the corresponding lower exhaust energy. Once 4° static injection timing retard was introduced, along with the EGR and the minimum MAT, a maximum NOx reduction of 49% was realized with only a 1.1% increase over the baseline BSFC.

In-Situ Thermophysical Properties of an Evolving Carbon Nanoparticle Based Deposit Layer Utilizing a Novel Infrared and Optical Methodology

2015 ◽  
Author(s):  
Ashwin A. Salvi ◽  
John Hoard ◽  
Dan Styles ◽  
Dennis Assanis
Keyword(s):  
Thermal Conductivity ◽  
Internal Combustion Engines ◽  
Linear Increase ◽  
Outlet Temperature ◽  
Combustion Engines ◽  
Deposit Thickness ◽  
Exhaust Gases ◽  
Gas Recirculation ◽  
Deposit Layer

The use of exhaust gas recirculation (EGR) in internal combustion engines has significant impacts on engine combustion and emissions. EGR can be used to reduce in-cylinder NOx production, reduce fuel consumption, and enable advanced forms of combustion. To maximize the benefits of EGR, the exhaust gases are often cooled with liquid to gas heat exchangers. However, the build up of a fouling deposit layer from exhaust particulates and volatiles result in the decrease of heat exchanger efficiency, and increase the outlet temperature of the exhaust gases, and decrease the advantages of EGR. This paper presents experimental data from a novel in-situ measurement technique in a visualization rig during the development of a 378 micron thick deposit layer. Measurements were performed every 6 hours for up to 24 hours. Results show a non-linear increase in deposit thickness with an increase in layer surface area as deposition continued. Deposit surface temperature and temperature difference across the thickness of the layer was shown to increase with deposit thickness while heat transfer decreased. The provided measurements combine to produce deposit thermal conductivity. A thorough uncertainty analysis of the in-situ technique is presented and suggests higher measurement accuracy at thicker deposit layers and with larger temperature differences across the layer. The interface and wall temperature measurements are identified as the strongest contributors to the measurement uncertainty. Due to instrument uncertainty, the influence of deposit thickness and temperature could not be determined. At an average deposit thickness of 378 microns and at a temperature of 100°C, the deposit thermal conductivity was determined to be 0.044 ± 0.0062 W/mK at a 90% confidence interval based on instrument accuracy.

In-Situ Use of an Optical Microscope for FIB Microsurgery of Planarized Devices

1999 ◽  
Author(s):  
Patrick J. Wolpert ◽  
Raymond A. Lee
Keyword(s):  
Surface Layer ◽  
Success Rate ◽  
Flip Chip ◽  
Infrared Camera ◽  
Optical Microscope ◽  
Success Rates ◽  
Throughput Time ◽  
Cycle Times ◽  
Work Chamber

Abstract The extensive use of planarization in many of today's leading process technologies significantly reduces the effectiveness of FIB circuit modification and debugging. Planarization has played a significant role in the development of denser chips with increasingly smaller geometries. Fully planarized devices offer little or no surface features on which the FIB operator relies for orientation and alignment. These conditions lead to increased debug cycle times and decreased success rates using the FIB. Recent FIB tool advancements in the field of C4 (controlled-collapse chip connection) flip-chip packaged device modification and debug have also made it easier to work on highly planarized conventional wire-bond technology. The integration of an optical microscope with an infrared camera into the work chamber allows the operator to view the circuitry under the surface layer. This paper will offer several techniques for overcoming the challenges that planarized devices present by using this in-situ optical microscope. When properly implemented, these techniques can significantly improve the success rate and throughput time of device modification on highly planarized parts.

Application of exhaust gas recirculation of NOx reduction in SI engines

2022 ◽  
pp. 155-187
Author(s):  
Dhinesh Balasubramanian ◽  
Inbanaathan Papla Venugopal ◽  
Rajarajan Amudhan ◽  
Tanakorn Wongwuttanasatian ◽  
Kasianantham Nanthagopal
Keyword(s):  
Nox Reduction ◽  
Exhaust Gas Recirculation ◽  
Exhaust Gas ◽  
Si Engines ◽  
Gas Recirculation

Assessing grouting mix thermo-physical properties for shallow geothermal systems

2020 ◽  
Author(s):  
Enrico Garbin ◽  
Ludovico Mascarin ◽  
Eloisa Di Sipio ◽  
Gilberto Artioli ◽  
Javier Urchueguía ◽  
...  
Keyword(s):  
Physical Properties ◽  
Heat Exchangers ◽  
Low Cost ◽  
Injection Pressure ◽  
Geothermal Systems ◽  
Geothermal Heat ◽  
Key Factor ◽  
Geological Formations ◽  
Thermo Physical Properties

<p>The main goal of the EU funded GEO4CIVHIC project is the development of more efficient and low-cost geothermal systems for conditioning retrofitting civil and historical buildings. In this framework, the identification of the most appropriate grout for different heat exchangers is a key factor for improving the overall efficiency of shallow geothermal systems. Therefore, a dedicated investigation was focused on the selection and optimization of the thermo-physical properties of grouting products to be used for:</p><ul><li>the sealing of the coaxial geothermal probes’ head characterized by different installation depths</li> <li>the sealing of the coaxial geothermal heat exchangers by filling the annular gap between the outer casing and the geological formations exposed to the wellbore</li> </ul><p> </p><p>In both cases, the thermo-physical behavior of conventional and thermal enhanced grouts has been determined in laboratory for the purpose of manufacturing satisfactory cement based grouts with a real in-situ application. On the one hand, it is important to identify the grout mixtures having a suitable in situ workability, that is those satisfying specific conditions in terms of injection pressure, grout flowability, open working time and costs. On the other, it is essential to determine those providing optimal heat transfer between the probe and the surrounding ground.</p><p>Several lab experiments were performed on commercially available and enhanced selected mixtures to define (i) the workability and the flowability of the grouts; (ii) fundamental properties like mechanical strength, thermal conductivity and permeability of the hardened materials; (iii) leakage and calorimetric behavior, useful to identify sealing properties and grout setting times; (iv) viscosity and (v) density of the cement based mixture able to give information about the grout rate of descent and thus its pumpability under pressure.</p><p>Lastly, according to the lab results, few grout mixtures were selected as the best choice to be applied in situ for sealing the head of the geothermal probes’ and the annular space between the outer casing and the geological formations exposed to the wellbore. Therefore, this work attempts to address a knowledge gap of the thermo-physical properties, behavior and characterization of grouts for borehole heat exchangers (BHE), that are little studied and known.</p><p> </p>

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