Industrial Gas Burners Research Articles

Numerical and experimental analysis of the formation of nitrogen oxides in a non-premixed industrial gas burner

Nitrogen oxides (NOx) formation in a non-premixed industrial gas burner is analyzed with Reynolds-averaged Navier-Stokes (RANS) computational fluid dynamics, using the Flamelet Generated Manifold (FGM) approach for chemistry and the Reynolds stress model for turbulence closure. Analysis and validation of the numerical methodology use both the RANS and the Large Eddy Simulation methods to study the Sandia flame D experiment. Four regimes of the gas burner, differing by thermal power, are studied experimentally and numerically, comparing measured and computed flue gas temperature and emissions. The flow features leading to NOx formation are analyzed. At low power, most NOx formation occurs in the flame core, where temperatures are highest. At high power, a significant amount of NOx forms where a secondary stream of oxidizer meets the high-temperature burnt gas stream. The NOx formation rate is modeled either by summing the contributions of the main paths relevant to the studied problem or via two variants of the FGM scalar transport approach. One of these variants features a correction to the transported scalar approach that enables accounting for the effects of non-adiabatic phenomena, e.g. heat radiation, on NOx formation without increasing the look-up table dimensionality and the required memory usage. The correction is shown to improve emission predictions over the baseline model, although quantitative differences between predicted and measured emission levels remain significant. The approach computing the NOx formation rate as by summing contributions yields the best agreement with measurements when the thermal path predominates, and the formation of nitrogen dioxide is negligible.

Numerical and Experimental Analysis of the Cold Flow Physics of a Nonpremixed Industrial Gas Burner

Abstract The flow field of a nonpremixed industrial gas burner is analyzed with Reynolds-averaged Navier–Stokes computational fluid dynamics validated against velocity and pressure measurements. Combustion is not modeled because the aim is optimizing the predictive capabilities of the cold flow before including chemistry. The system's complex flow physics, affected by a 90 deg turn, backward and forward facing steps, and transversal jets in the mainstream is investigated at full and partial load. The sensitivity of the computed flow field to inflow boundary condition setup, approach for resolving/modeling wall-bounded flows, and turbulence closure is assessed. In the first sensitivity analysis, the inflow boundary condition is prescribed using measured total pressure or measured velocity field. In the second, boundary layers are resolved down to the wall or modeled with wall functions. In the third sensitivity analysis, the turbulence closure uses the k−ω shear stress transport eddy viscosity model or two variants of the Reynolds stress model. The agreement between the predictions of most simulation setups among themselves and with the measurements is good. For a given type of inflow condition and wall flow treatment, the ω-based Reynolds stress model gives the best agreement with measurements among the considered turbulence models at full load. At partial load, the comparison with measured data highlights some scatter in the predictions of different patterns of the flow measurements. Overall, the findings of this study provide insight into the fluid dynamics of industrial gas burners and guidelines for their simulation-based analysis.

Mono-Blok Tipte Bir Doğal Gaz Yakıcının Sayısal Analizi ve Deneysel

Fossil fuels are still one the major sources of the energy production. Fuels, utilized in the power generation, especially in industrial scale applications, are almost hydrocarbons in gaseous, liquid or solid phases. In combustion of gaseous fossil fuels, besides the several other emissions carbon monoxide and nitric oxide which are identified as the main suspects of the environmental pollution are produced. In this study, the flow field and the emission statistics of an industrial scale gas burner was investigated numerically. The burner and the assembled combustion chamber have been modelled using ANSYS-Fluent software. The standards for flue gas emissions of gas burners defined in TSE EN 676:2000 Class-3 have been taken into account. One of the most important emission of NOx level given in that standard, limited to be less than 80 mg/kWh, has been initially computed for the existing burner and then for the modified burner designs. Both the velocity and temperature fields are calculated and represented in terms of contour plots. The emission results are collected at the exit of the combustion chamber and the chamber wall temperatures have been also computed. The numerical model results were validated with the available experimental measurements obtained from on-site test facilities.

DEFECTS IN LARGE HOLLOW POROUS CYLINDRICAL FILTERS MADE BY SHS

The relevance of research is connected with the use of ceramic filters in biology and medicine for fine filtration of air and biological fluids abroad. Due to the unique combination of chemical and thermal resistance, high strength and thermal conductivity, ceramic filters are used to clean aggressive liquids, superheated high pressure steam and other gases. The dependence of burning rate on the relative density and granulometric composition of FeTiO 3 –Al–Si–SiO 2 –C powder mixtures is studied. The paper provides experimental results on the influence of initial charge compact density and composition on the quality of products obtained. The main types of defects appearing in the synthesis are identified. The causes of defects are found. Feedstock with particle sizes larger than specified values results in penetrations (cavities) occurring in the product. Their formation is caused by the increased liquid phase content in these regions due to decelerating reaction rate and rising temperature. Higher density results in transverse and longitudinal laminations in the product. Such laminations are formed under the pressure of gaseous products with the low gas permeability of the sample that declines as density increases. The technology of self-propagating high-temperature synthesis of large porous products is developed with the photographs of filtering elements presented: for the typical industrial gas burner GG-2, for superheated steam and demineralized water purification (filtering elements used in polyvinyl chloride process vessels at JSC «Sayanskkhimplast»), for iron removal from artesian water. Defect-free large porous products can be obtained with an optimal ratio of the sample grain size distribution and density, as well as reaction rate and heat removal rate.

Numerical simulation of flow, combustion and NO emission of a fuel-staged industrial gas burner

Three dimensional numerical simulations were performed to optimize the geometrical parameters of a fuel-staged low NOx gas burner. The effect of the primary gas injection angle (α), the staged gas injection angle (β) and position of the staged gun (H) on flame size and NO emission was analyzed based on the contours of temperature, stoichiometric mixture fraction, rate of thermal NO and the global NO emission. The predicted results were validated with the experimental measurements of the full scale burner (1.4 MW) at different excess air factors. The results indicate that H is the most important factors affecting the NO emission, followed by β and α respectively. The chemical flame heights increase with the increase of β and the decrease of H but the effect of α is negligible. Finally, α = 70°, β = 30° and H = 36 mm are recommended as the optimized results.

A reactor network model for predicting NOx emissions in an industrial natural gas burner

A chemical reactor network (CRN) is developed and applied to the modeling of a natural gas burner. The CRN development is based on experimental and CFD simulation results of the BERL 300 kW test. The CRN element arrangement, reactor volumes, and flow splits are adjusted based on the best agreement with characteristic temperatures of the reactive flow, aiming to reproduce the experimental NOx emissions data. A sensitivity analysis and a parametric study of the CRN are carried out to evaluate its sensitivity to the flow splits adjustments and its ability to predict emission with air preheat and turndown operation, as well as the influence of the reaction mechanism employed. The best agreement was obtained in the air preheat simulations using Konnov 0.4 mechanism, while the GRI-Mech 3.0 is accurate only within 110 K preheating. The turndown operation results are relatively accurate for turndown ratio between 1.0 and 1.3.

Application of CFD in Studying and Modification of Gas Burners of Catalytic Reforming Unit of Abadan Refinery in Iran

article is a report of the attempts which were made to model an industrial premix gas burner which was operating in one of the furnaces of the Catalytic Reforming Unit (CRU) of Abadan refinery. The main objective of the modeling was to investigate on the effect of the structural geometry of the burner on its mode of operation, i.e. complete combustion of the gas, maximum generation of heat and production of a proper flame configuration. For this goal, fundamental equations of the conservation of mass, momentum and energy for fuel-air mixture flowing in the burner were written and solved by using the Computational Fluid Dynamic (CFD) techniques and the results were analyzed. The main conclusion of the research was that various effects of the changes in the burner come to appear and an appropriate correction on the burner was recommended to the industry.

Experimental Study of Local Axial Mixing in a Pilot-Scale Cold Burner

The residence time distribution (RTD) approach was used to characterize the flow and mixing behavior of burners. This analysis consists of injecting an inert gaseous tracer into the feed and measuring its change in concentration at various detection points. The responses are then used to characterize the flow behavior and, thus, the local mixing in the space delimited by the injection and probe points. The outcome of this RTD analysis is a flow model that, combined with an appropriate kinetics, constitutes an efficient tool in examining the ways to reduce NOx emissions in existing installations. A replica made in plastic at a 1:1 scale of an industrial gas burner was used for cold experiments. As preliminary information, a chart of local mixing in the axial section of the burner chamber was obtained. Even though far from working conditions, cold experiments are beneficial because they reveal the existence of possible major flow disturbances, leading to imperfect or incomplete combustion, a source of NOx.

Molybdenum Silicide Based Materials and Their Properties

Molybdenum disilicide (MoSi2) is a promising candidate material for high temperature structural applications. It is a high melting point (2030 °C) material with excellent oxidation resistance and a moderate density (6.24 g/cm3). However, low toughness at low temperatures and high creep rates at elevated temperatures have hindered its commercialization in structural applications. Much effort has been invested in MoSi2 composites as alternatives to pure molybdenum disilicide for oxidizing and aggressive environments. Molybdenum disilicide-based heating elements have been used extensively in high-temperature furnaces. The low electrical resistance of silicides in combination with high thermal stability, electronmigration resistance, and excellent diffusion-barrier characteristics is important for microelectronic applications. Projected applications of MoSi2-based materials include turbine airfoils, combustion chamber components in oxidizing environments, missile nozzles, molten metal lances, industrial gas burners, diesel engine glow plugs, and materials for glass processing. In this paper, synthesis, fabrication, and properties of the monolithic and composite molybdenum silicides are reviewed.

Scaling Laws for NO x Emission Performance of Burners and Furnaces from 30 kW to 12 MW

A general analytical approach for scaling NO x emissions from burners and furnaces is presented, together with the scaling model for NO x emissions performance that results when this approach is applied to a broad class of swirl-stabilized industrial gas burners. The model is based on results from a set of collaborative burner scaling experiments on a generic gas burner and furnace design at five different scales having near-uniform geometric, aerodynamic, and thermal similarity and uniform measurement protocols. This collaborative effort provides the first NO x scaling data over the range of thermal scales from 30 kW to 12 MW, including input-output measurements as well as detailed in-flame measurements of NO, NO 2, CO, O 2, unburned hydrocarbons, temperature, and velocities at each scale. The in-flame measurements allow identification of key sources of NO x production. The underlying physics of these NO x sources lead to scaling laws for their respective contributions to the overall NO x emissions performance. It is found that the relative importance of each source depends on the burner scale and operating conditions. The scalings for these NO x sources are combined in a comprehensive scaling model for NO x emission performance. Results from the scaling model show good agreement with experimental data at all burner scales and over the entire range of turndown, staging, preheat, and excess air dilution, with correlations generally exceeding 90%. The scaling model permits design trade-off assessments for a broad class of burners and furnaces, and allows performance of full industrial-scale burners and furnaces of this type to be inferred from results of small-scale tests.

Mean Streamwise Velocity Measurements in a Triple Jet of Equilateral Triangular Configuration

Multijet flows arise in several applications such as jet engine/rocket combustors, the thrust augmenting ejectors for VTOL/STOL aircraft, and industrial gas burners. In order to achieve proper combustion, thrust development, and reduction in the noise level, it is often desirable to control the inter-mixing between the jets and also the entrainment of the surrounding atmosphere. This, in turn, requires a detailed study of the behavior of high speed jets in multijet configuration. The situation of interest here is an array of three axisymmetric nozzles set in a common end wall with equal spacing in a triangular configuration. The reason why this particular configuration has been chosen is that it promotes bending of the jet axes toward each other, thus leading to greater mixing. In the present study, experiments have been conducted to investigate the effect of stagnation pressure ratio and nozzle spacing upon the mean flow characteristic of compressible jets in triangular configuration. The individual flow features of the vertex jet and the base twin jet are analyzed and their contributions to the axis switching as well as the overall triple jet behavior are highlighted.

ChemInform Abstract: Diminution of NOx at Industrial Gas Burners.

ChemInform Abstract: Diminution of NOx at Industrial Gas Burners.

Gas burner control using microprocessors

The application of microprocessors to the direct supervision of industrial gas burners offers several advantages over existing technology. The achievement of adequate safety standards poses particular design problems which are not conveniently solved by multiple-channel redundancy. A hierarchical multiple-burner control system is described in which hardware and software combine to achieve required levels of safety. The architecture permits comprehensive facilities for reading out information on the state of the various burners, both locally and at a remote location. In hazardous or noisy environments a fibre-optic link can be used for remote communication.

Esso Energy Award Lecture, 1983 The development of a recuperative burner for gas-fired furnaces

It is common for over 50% of the heat input to high temperature industrial furnaces to be lost in the flue gases. Owing to high cost, complexity and service problems, recuperators to recover this heat have not been widely used in the past. During the 1960s the design of industrial gas burners improved considerably. So by the early 1970s it was feasible to develop a device that incorporated, in a single unit, the functions of a burner, flue and recuperator. This became known as the recuperative burner. The technical problems to be overcome to ensure reliable operation and durability of this device, when placed in a potentially corrosive environment at up to 1600°C, are considerable. In addition, the wide variety of furnace types and applications necessitated an extensive field trial and demonstration programme. The development also serves as a useful vehicle for illustrating the time scales and resources involved in steering an industrial development from the laboratory through to common use. The important stages and roles of the various parties can be identified and lessons about investment policy in energy saving equipment learnt.

Study of Combustion Noise from Industrial Gas-burner by Spectrum Analysis

Study of Combustion Noise from Industrial Gas-burner by Spectrum Analysis

THE ROLE OF GAS IN ENVIRONMENTAL CONTROL

The gases comprising the atmosphere are in dynamic balance both with the oceans and the dry land of the continents. The mechanisms which operate to keep the atmospheric content of oxygen, nitrogen, carbon and sulphur constant are now well defined. The capacity of the system to absorb excess gaseous impurities is adequate on a global basis with the exception of carbon dioxide.Air pollution is thus a local problem resulting from the overloading of a particular air space with contaminants. The greater part of air pollution is due to the combustion of fossil fuels. Ease of control and virtual freedom from sulphur give natural gas an advantage over liquid and solid fuels as far as air pollution control is concerned. Oxides of nitrogen are produced when natural gas is burned but in smaller quantities than in the combustion of other fuels. In high capacity industrial gas burners where oxides of nitrogen may be generated in large quantities control is easier and can achieve a lower level of oxides of nitrogen than is the case with other fuels.The large scale use of natural gas to solve the air pollution problems of Pittsburgh, Los Angeles and many other cities is proof of the usefulness of gas in this respect. Specialised applications include use in incinerators and industrial after burners. Advances in removal of impurities from fuels and of air pollutants from products of combustion combined with rising gas prices will in time displace gas from its preeminent position in air pollution control. It is, however, likely to retain its advantage in small installations and in dense urban areas. In public and private transport its use will probably remain limited.While technological developments in the distant future may eventually displace fossil fuels, gas will have a large share of the fuel market until that day comes and will contribute effectively to the control of air pollution.