NOx Emissions in a Steel Reheat Furnace Firing By-Product Fuels

2001 ◽  
Author(s):  
Bradley R. Adams ◽  
Dave H. Wang
Keyword(s):  
Low Cost ◽  
Nox Reduction ◽  
Coke Oven ◽  
Cfd Modeling ◽  
Stoichiometric Ratio ◽  
Nox Emissions ◽  
Confined Space ◽  
Nox Formation ◽  
Reheat Furnace ◽  
Bottom Zone

Abstract A DOE-funded program was used to understand the mechanisms that control the formation of NOx during the combustion of steelmaking by-product fuels and to investigate possible low-cost control options to minimize the NOx emissions. This paper discusses the CFD modeling results of NOx emissions in a reheat furnace. The reheat furnace has a total of 20 burners distributed over three firing zones. The furnace is fired at a rate of 250 × 106 Btu/hr and an overall stoichiometric ratio of 1.06 (fuel lean). Fuels with heating values of approximate 500 Btu/SCF were examined, including coke oven gas (COG), blast furnace gas (BFG) and a blend of COG, BFG, natural gas (NG) and nitrogen. A good range of process variables was modeled to examine effects of fuel type, air preheat, stoichiometric ratio, firing rate and burner stoichiometry distribution on NOx emissions. Modeling results indicated that NOx formation in the reheat furnace is dominated by thermal NO, with some variation depending on the fuel fired. Temperature profiles showed an effective separation of the furnace interior into top and bottom zones as a result of the steel slab barrier. Higher temperatures characterized the bottom zone and elevated NOx levels as a result of the confined space and enhanced fuel air mixing provided by the slab supports. Results also showed that reburning of NOx plays a significant role in final NOx emissions with 30–40% of NOx formed being reduced by reburning in most cases. Modeling identified that operating the side burners in each burner zone slightly substoichiometric (while maintaining the overall furnace stoichiometry at 1.06) provided significant NOx reduction via reburning. NOx reductions of 23% and 30% were predicted when firing with COG and COG-NG-Air fuels, respectively. Overall furnace exit temperatures and heat flux profiles were not significantly affected by the biased firing.

CFD Modeling of NOx Reduction Technologies in Utility Boilers

2000 ◽  
Author(s):  
Marc A. Cremer ◽  
Bradley R. Adams ◽  
David H. Wang ◽  
Michael P. Heap
Keyword(s):  
Nox Reduction ◽  
Electric Utility ◽  
Cfd Modeling ◽  
Nox Formation ◽  
Modeling Tools ◽  
Chemical Mechanisms ◽  
Utility Boilers ◽  
Clean Air ◽  
Nox Control ◽  
Selective Noncatalytic Reduction

Abstract This paper discusses the development and application of CFD modeling tools that have been utilized to assess and design NOx reduction systems that are currently being evaluated by the electric utility industry. Stringent limits on NOx emissions have been imposed by the Clean Air Act Amendments, and a number of NOx reduction technologies are available to help meet these limits including selective noncatalytic reduction (SNCR) and reburning, as well as various combinations of these. This paper discusses the development and implementation of global and reduced chemical mechanisms for NOx formation/destruction into a comprehensive CFD code so that these various options for NOx control can be evaluated. Also, some examples showing the application of these tools to full-scale utility boilers utilizing low-NOx burners, air staging, and SNCR are presented.

scholarly journals Effect of Steam Addition on the Flow Field and NOx Emissions for Jet-A in an Aircraft Combustor

2016 ◽  
Vol 33 (4) ◽  
Author(s):  
Rui Xue ◽  
Chunbo Hu ◽  
Theoklis Nikolaidis ◽  
Pericle Pilidis
Keyword(s):  
Nox Reduction ◽  
Chemical Reactor ◽  
Steam Injection ◽  
Nox Emissions ◽  
Nox Formation ◽  
Steam Content ◽  
Injection Technology ◽  
Integrated Performance ◽  
Processing Techniques ◽  
The Impact

AbstractThe steam injection technology for aircraft engines is gaining rising importance because of the strong limitations imposed by the legislation for NOx reduction in airports. In order to investigate the impact of steam addition on combustion and NOx emissions, an integrated performance-CFD-chemical reactor network (CRN) methodology was developed. The CFD results showed steam addition reduced the high temperature size and the radical pool moved downstream. Then different post-processing techniques are employed and CRN is generated to predict NOx emissions. This network consists of 14 chemical reactor elements and the results were in close agreement with the ICAO databank. The established CRN model was then used for steam addition study and the results showed under air/steam mixture atmosphere, high steam content could push the NOx formation region to the post-flame zone and a large amount of the NOx emission could be reduced when the steam mass fraction is quite high.

CFD Applications on Selective Catalytic NOx Reduction (SCR) Systems

2003 ◽  
Author(s):  
Jia Mi ◽  
Dan A. Pitsko ◽  
Tim Haskew
Keyword(s):  
Power Generation ◽  
Pressure Drop ◽  
Nox Reduction ◽  
Measurement Data ◽  
Cfd Modeling ◽  
Nox Emissions ◽  
Steam Power ◽  
Flow Models ◽  
Design And Optimization ◽  
Cfd Applications

For the last several years, CFD modeling has been successfully used in Southern Company as one of the design and analysis tools to provide engineering insight to retrofitting Selective Catalytic NOx Reduction (SCR) systems to coal-fired steam power generation plants. SCR technology is the most effective method for reducing NOx emissions by at least 75% ∼ 90%. This paper will summarize a few selected CFD applications that were proved to be essential in the SCR design and optimization processes. For validation purposes, some of the CFD results, such as pressure drop, were compared with the available measurement data from the scaled physical flow models. They generally agreed well.

In-Cylinder NOx Reduction Using Different Camshaft Timings on Diesel Engines

2014 ◽  
Author(s):  
Lucas Comitre ◽  
Flavio G. Lehmann
Keyword(s):  
Low Cost ◽  
Nox Reduction ◽  
Intake Manifold ◽  
Nox Emissions ◽  
Valve Timing ◽  
Main Criterion ◽  
Engine Simulation ◽  
Intake Stroke ◽  
Timing Strategies ◽  
Fresh Charge

Over time, environmental protection standards have become more strict and complex. Nitrogen oxides (NOx) are regulated pollutants produced by combustion in a diesel engine. In this project, camshaft timing modifications were studied as a way of reducing NOx emission levels while using low cost hardware. Different valve timing strategies were proposed and modelled using engine simulation. This project was based on two concepts. The first was to open the intake valve during the exhaust stroke, thus expelling burnt gases from the cylinder into the intake manifold and then later re-admitting these gases into the cylinder during the intake stroke of the next cycle. The second was to open the exhaust valve during the intake stroke, allowing burnt gases from the exhaust manifold to enter the cylinder at the same time as the fresh charge enters. Both technologies studied were able to recirculate the exhaust gases without an external EGR system. The EGR amount was controlled by either an intake throttle or an exhaust throttle. The amount of EGR was predicted using engine simulation. The brake-specific fuel consumption (BSFC) and brake-specific NOx (BSNOx) trade off was the main criterion used to select the best technology, although other features such as predicted manifold pressures and engine-out soot were also considered. The results indicate that, by using increased amounts of EGR while varying the intake or exhaust throttle position, NOx emissions can be reduced with a slight BSFC penalty. These methods are thus a low cost means of reducing engine-out NOx emissions.

RSCR® System to Reduce NOx Emissions From Boilers

2009 ◽  
Author(s):  
Richard F. Abrams ◽  
Robert Faia
Keyword(s):  
Selective Catalytic Reduction ◽  
Flue Gas ◽  
Heat Recovery ◽  
High Efficiency ◽  
Catalytic Reduction ◽  
Low Cost ◽  
Nox Reduction ◽  
Waste To Energy ◽  
Nox Emissions ◽  
Reaction Products

Babcock Power Environmental (BPE), a Babcock Power Inc. company, has developed a new, innovative, high-efficiency NOx reduction technology designed to greatly reduce the NOx emissions from waste to energy (WTE) boilers at relatively low cost. This “tail-end” system uses Selective Catalytic Reduction (SCR) to achieve the high reduction performance. Conventional SCR catalyst cannot be used in the traditional “high-dust” location, downstream of the economizer because constituents in the ash would poison the catalyst quickly, rendering it useless. Thus, the Regenerative Selective Catalytic Reduction (RSCR®) system is designed to operate at the end of the plant before the flue gas is discharged to the stack. The process utilizes a reactant (usually aqueous ammonia) to be added to the flue gas stream upstream of the RSCR to reduce NOx to harmless reaction products, N2 and H2O. The RSCR combines the efficient heat recovery, temperature control, reactant mixing, and catalyst into a single unit and provides the maximum NOx reduction and heat recovery practical. The paper will describe the overall predicted performance of a typical WTE boiler plant using this new technology. The paper will also provide actual operating data on the RSCR, which has been retrofitted to four biomass-fired units.

THE METHOD OF NITROGEN OXIDE EMISSION REDUCTION DURING THE COMBUSTION OF GASEOUS FUEL IN MUNICIPAL THERMAL POWER BOILERS

2020 ◽  
Vol 5 (3) ◽  
pp. 18-33
Author(s):  
Sylwia Janta-Lipińska ◽  
Keyword(s):  
European Union ◽  
Emission Reduction ◽  
Thermal Power ◽  
Nox Reduction ◽  
Gaseous Fuel ◽  
Nox Emissions ◽  
The European Union ◽  
Nitrogen Oxide Emission ◽  
Boiler Efficiency ◽  
Injection Technology

The nitrogen oxides in a flame of burning fuel can be created by many mechanisms. The amount of NOx concentration emitted to the ground atmosphere mainly depends on the type of fuel burned in the industrial and heating boilers. Changes in the country's thermal policy and requirements that are set for us by the European Union States are forcing us to reduce greenhouse gas emissions. Directed metered ballast method is one of the most attractive techniques for reducing NOx emissions. In recent years, moisture injection technology is still investigated on low and medium power thermal power boilers operating on gaseous fuel. The goal of this work was to perform the investigations of the process of a moisture injection into the zones of decisive influence (SDW-I and SDW-II) on steam and water boilers: DKVR 10-13, DKVR 20-13, DE 25-14 and PTVM-50. The obtained results clearly show how the proposed method affects NOx reduction and boiler efficiency.

A NOx Reduction Project for a GT11 Type Gas Turbine

2005 ◽  
Author(s):  
Lars O. Nord ◽  
David R. Schoemaker ◽  
Helmer G. Andersen
Keyword(s):  
Power Plant ◽  
Distribution System ◽  
Gas Turbines ◽  
Nox Reduction ◽  
Measurement Data ◽  
Combustion Stability ◽  
Study Phase ◽  
Nox Emissions ◽  
Ambient Conditions ◽  
Exhaust Temperature

A study was initiated to investigate the possibility of significantly reducing the NOx emissions at a power plant utilizing, among other manufacturers, ALSTOM GT11 type gas turbines. This study is limited to one of the GT11 type gas turbines on the site. After the initial study phase, the project moved on to a mechanical implementation stage, followed by thorough testing and tuning. The NOx emissions were to be reduced at all ambient conditions, but particularly at cold conditions (below 0°C) where a NOx reduction of more than 70% was the goal. The geographical location of the power plant means cold ambient conditions for a large part of the year. The mechanical modifications included the addition of Helmholtz damper capacity with an approximately 30% increase in volume for passive thermo-acoustic instability control, significant piping changes to the fuel distribution system in order to change the burner configuration, and installation of manual valves for throttling of the fuel gas to individual burners. Subsequent to the mechanical modifications, significant time was spent on testing and tuning of the unit to achieve the wanted NOx emissions throughout a major part of the load range. The tuning was, in addition to the main focus of the NOx reduction, also focused on exhaust temperature spread, combustion stability, CO emissions, as well as other parameters. The measurement data was acquired through a combination of existing unit instrumentation and specific instrumentation added to aid in the tuning effort. The existing instrumentation readings were polled from the control system. The majority of the added instrumentation was acquired via the FieldPoint system from National Instruments. The ALSTOM AMODIS plant-monitoring system was used for acquisition and analysis of all the data from the various sources. The project was, in the end, a success with low NOx emissions at part load and full load. As a final stage of the project, the CO emissions were also optimized resulting in a nice compromise between the important parameters monitored, namely NOx emissions, CO emissions, combustion stability, and exhaust temperature distribution.

scholarly journals Microwave Assisted-Hydrothermal Synthesis of Nickel Ferrite Nanoparticles

2018 ◽  
Vol 34 (5) ◽  
pp. 2577-2582
Author(s):  
Mohamed H. H. Mahmoud ◽  
Mahmoud M. Hessien
Keyword(s):  
Nickel Ferrite ◽  
High Performance ◽  
Fine Particles ◽  
Low Cost ◽  
Nickel Chloride ◽  
Heating Time ◽  
Stoichiometric Ratio ◽  
Microwave Assisted ◽  
Xrd Patterns ◽  
Co Precipitation

Nanomagnetic ferrite materials are of great technological importance in several industries due to their high performance, ease of preparation and low cost. The ferrite properties are based on composition, structure and methods of preparation. Nickel ferrite, NiFe2O4, was prepared by the simple microwave assisted-hydrothermal method. Nickel chloride and ferric chloride solutions (stoichiometric ratio of 1: 2 respectively) were mixed, the pH was raised to 10.5 and the mixture was heated at 180 °C in a closed Teflon vessel using a microwave oven at different periods of time (2 - 24 h). The formed powders were examined by XRD, TEM, and VSM. The intensity of nickel-ferrite in the XRD patterns increased with time owing to increase in crystallinity of the formed phase. The TEM images showed that, the size was in the range of 20-40 nm and contents of fine particles noticeably decreased with increasing reaction time to 4-6 hrs and contents of more regular cubic particles are formed. The NiFe2O4 magnetization was continuesly increased with raising the heating time from 2h (9 emu/g) to 24 h (43 emu/g) which may be due to the high purity and crystallinity of the formed NiFe2O4. The results showed that the properties of the formed ferrite can be tailored by controlling the heating time. Microwave assisted co-precipitation followed by hydrothermal digestion resulted in a substance of good homogeneity and crystallinity at a short time.

scholarly journals Nb2O5 nanoparticles obtained by microwave assisted combustion synthesis under different conditions

2021 ◽  
Vol 15 (2) ◽  
pp. 128-135
Author(s):  
Thaís Luiz ◽  
Fabio Nakagomi ◽  
Reny Renzetti ◽  
Guilherme Siqueira
Keyword(s):  
Combustion Synthesis ◽  
Diffuse Reflectance Spectroscopy ◽  
Low Cost ◽  
Synthesis Method ◽  
Particle Growth ◽  
Synthesis Temperature ◽  
Band Gap Energy ◽  
Stoichiometric Ratio ◽  
Synthesis Of Nanoparticles ◽  
Microwave Assisted

The microwave assisted combustion synthesis (MACS) as a new, quick and low cost synthesis method was used for preparation of niobium pentoxide (Nb2O5) powders. The present paper investigated the effect of reactant concentrations (ammonium niobium oxalate, urea and ammonium nitrate) on the characteristics of Nb2O5 nanoparticles. Three samples were synthesized with stoichiometric ratio between the fuel and oxidant (C1), excess of oxidant (C2) and excess of fuel (C3). In all samples, Nb2O5 crystalline nanoparticles with irregular morphology were detected. The synthesis of nanoparticles with smaller diameter in the C2 and C3 samples was confirmed by greater values of band gap energy measured through UV-Visible diffuse reflectance spectroscopy (indicating quantum confinement) and by the Rietveld refinement of X-ray diffraction patterns. The results showed that the amounts of oxidant and fuel can change synthesis temperature, influencing the final characteristics of the particles, such as size and existent phases. In these cases the excess of oxidant and fuel in the C2 and C3 samples, respectively, decreases the average synthesis temperature and decelerates the particle growth and the formation of the monoclinic phase.

scholarly journals Biomagnetic Monitoring vs. CFD Modeling: A Real Case Study of Near-Source Depositions of Traffic-Related Particulate Matter along a Motorway

Atmosphere ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1285
Author(s):  
Sarah Letaïef ◽  
Pierre Camps ◽  
Thierry Poidras ◽  
Patrick Nicol ◽  
Delphine Bosch ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Particulate Matter ◽  
Cfd Simulation ◽  
Low Cost ◽  
Precast Concrete ◽  
Cfd Modeling ◽  
Concrete Wall ◽  
Fluorescence Measurements ◽  
Computational Fluid Dynamics Cfd

A test site located along a 12-lane motorway east of Montpellier, France, is used to evaluate the potential of biomagnetic monitoring on traffic-related particulate matter (PM) to parametrize a computational fluid dynamics (CFD) simulation of the local airflow. Two configurations were established on the site with three vegetated flat-top earth berms of a basic design, and a fourth one was located windward to the traffic roofed with a 4-m-high precast concrete wall. As a first step, PM deposition simultaneously on plant leaves, on low-cost passive artificial filters, and on soils was estimated from proxies supplied by magnetic and X-ray fluorescence measurements on both sides of the motorway. These latter revealed that traffic-related pollutants are present on soils samples highlighted with a clear fingerprint of combustion residues, and wears of breaks, vehicles, and highway equipment. Maximum PM accumulations were detected in the lee of the berm–wall combination, while no significant deposition was observed on both sides of the flat-top earth berms. These results are in line with measurements from PM µ-sensors operated by the regional state-approved air quality agency. Finally, we compared the experimental measurements with the outcomes of a computational fluid dynamics (CFD) modeling based on the Reynolds-Averaged Navier–Stokes (RANS) equations that consider the traffic-induced momentum and turbulence. The CFD modeling matches the experimental results by predicting a recirculated flow in the near wake of the berm–wall combination that enhances the PM concentration, whereas the flat-top berm geometry does not alter the pollutants’ transport and indeed contributes to their atmospheric dispersion.

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