Nitrogen oxides reduction in a porous burner shahrooz afsharvahid school of mechanical engineering the university of adelaide, south australia 5005 a thesis submitted in fulfilment of the requirements for the degree of doctor of philosophy july 2016. A lean gas mixture is introduced into the porous medium, where the gas flow rate is changed at a regular interval of time and, as a result, the combustion front is confined within a specific region of the porous medium. Department of chemical engineering, lund university 28,100 views. The model is of combustion in a threedimensional porous medium. The existing setup was significantly modified with the aim of providing improved data quality and data rate, reduction of interferences and additional species information.
The present work focuses on thermoelectric generation using a porous media burner with flame stabilization at the interface of two porous bodies. Combustion in porous media is utilized in advanced boiler and surface burners. As one promising example, porous media combustion pmc technology has been developed to reduce no x emissions and to enable compact burner which achieves efficient and stable combustion with a. Pdf porous media of lzsa glassceramic for burner applications.
The new burner is a twosection and doubledeck porous medium with gas inlets at both ends. This results in an extensive interphase energy and momentum transfer between the fluid and solid phases. The preheat zone consists of alumina spheres of 5 mm diameter and the combustion zone is made up of 10 ppi pores per inch sic ceramic foam. Matrix stabilized porous inert media combustion used in burner technology along with different materials and applications have been elaborately described in previous studies 3 4 56. In the course of the experiments different porous media and ceramic insulation materials were tested. Pdf applications of porous media combustion technology. Numerical simulation of a new porous medium burner with two. A porous media burner comprises an outer casing of impermeable material separated by a gas distributing space from an inner hollow core, open at one end, of a porous medium.
Combustion characteristics of butane porous burner for. Applications of porous media combustion technology a. An experimental study of stable and unstable operation range. In this study, a new burner was proposed based on the combustion mechanism of the methaneair mixture in the porous medium and the preheating effect. The heat regeneration effect of the porous matrix and the low degree of thermal nonequilibrium between the gas and the solid phases keep temperature values above the minimum necessary for combustion and hence the co and no x production at extremely low levels.
In this work, a study on the effect of porous material on the thermal behaviour of a biogas operated pmb is presented. Steadystate combustion regimes for gas combustion in inert porous media. A system for converting combustion heat into electric power is proposed on the basis of gas combustion in a thermoelectric porous element. The properties of the porous materials are crucial to the combustion performance, as they directly influence the degree of heat recirculation occurring in the burner. They called the proposed burner, which uses porous media to transfer some of the hot gas enthalpy to the premixed. Porous burners for household cooking applications in 1996, jugjai and sanitjai 1996 proposed a new burner design to improve the thermal efficiency of conventional burners used for domestic applications.
The porous samples were wrapped in insulation and housed in a quartz tube see fig. These changes are presented and discussed in detail. Pdf experimental thermoelectric generation in a porous. One of the essential mechanics of nox formation is thermal, and it mainly depends on the flame. This porous burner technology is critical when generating power from thermoelectric devices, smallscale heating, and combustion of lowcalorific value landfillseepage gases. Alumina reticulated d and honeycomb a porous foams. Advanced laser based measurements in porous media combustion. In particular we focus on ultralean combustion, where the. A bed of porous media is thus able to remove particles considerably smaller than the voids within the bed.
Dec 17, 2008 superadiabatic combustion in porous media allows a stable burning of ultralean methaneair mixtures, far below flammability limits. In this video, we will talk about how to calculate the porous media coefficients for a simple homogeneous porous media from the experimentally obtained velocity vs pressure loss data. The quality of the combustion process in the porous burners depends on the length of flame in the porous medium. Porous media allow for the premixed and nonpremixed combustion of gas fuels. Stabilized combustion in porous media applications of the porous burner technology in energy and heat engineering. Reaction layer was made up of alumina discrete type while preheat layer. The result was an optimised burner ib, which had very low. A twodimensional mathematic model was set up, and the distributions of temperature and concentrations of. A specially designed porous media burner has applied to burn with blast furnace gas. Design and modeling of a heat exchanger for porous combustor.
Results show that power input, heat capacity of porous matrix, arrangement of porous blocks, and annular heat recirculation are major factors that influence the propagation of combustion wave. Furthermore, the surface area per unit volume of porous matrix is very large, of the order of 10 4 m. The project titled experimental and numerical investigation of flame stabilization in porous media burner for hydrocarbonhydrogen fuels, is funded by dst serb. Based on these data, the flame is found to be most stable if the equivalence ratio. To promote the effective utilization of different varieties of lowcalorific gas mixtures in a porous media burner, combustion behaviors of three typical lowcalorific gas mixtures in a twolayer porous burner are simulated with a twoenergy and onedimensional transient model. For the application of inert porous media in high pressure combustion, a velocity stabilisation was employed. The chapter discusses the fundamentals and application of combustion in porous burners. In this present work, dual layered micro burner was built with predefined thickness of reaction and preheat layer.
Laserinduced phosphorescence applications in surface. Porous burners for leanburn applications sciencedirect. The temperature distribution, the ignition position, flame structure were analyzed. A mathematical model enables a numerical parametric study for applications that porous combustion is involved. Potential of porous media combustion technology for household. Combustion wave propagation of a modular porous burner. Research article combustion characteristics of butane porous.
The porous media burner of claim 1 wherein the wall thickness of the hollow core is between onefourth inch and 2 inches. Experimental thermoelectric generation in a porous. Introduction combustion processes in porous media burners pmbs have found increasing attraction during the last two decades. Figure 16 schematic of a porous media burner used for household heating 37 figure 17 a detailed view inside the heat exchanger elements b heat exchanger 38 figure 18 porous burner heat exchanger thermal efficiency relating to lhv 40. Porosity effects in flame length of the porous burners. Porous burners for leanburn applications porous burners for leanburn applications wood, susie.
A lzsa li2ozro2sio2al2o3 glassceramic porous media produced by the replication method has been studied for relatively low temperature applications. Pdf flow through porous media ali alshahad academia. How do i calculate the porous media parameters youtube. The stable combustion of industrial gas in porous media burner was studied in this paper. Twodimensional numerical simulation of combustion and heat. Reticulated ceramic or metallic foams have an openpore structure made up of an interconnected network of dodecahedrallike cells, with solid struts forming the cell edges. The gas infrared porous burner radimax mainly consists of the optimised porous materials as shown in figure 2. Experimental study of multispecies gas combustion in a. Pdf experimental and numerical studies of porous media. An investigation of internal flame structure in porous media. In this paper, the computational fluid dynamic cfd is used to investigate the porosity effects on the flame length of the combustion process in porous burner. The model represents conservation of mass and energy for. Superadiabatic radiant porous burner with preheater and radiation.
Experimental analysis of biogas combustion with different. This technology combines higher power densities, high efficiencies, higher power dynamic ranges and very low emissions of pollutants nox, co. The fifth group concerned with burning liquid fuels inside the porous media, so as to best uti. World population is doubling about every thirty five years. Pdf potential of porous media combustion technology for. This work continues our previous measurements in such combustion systems.
Porous medium burners are characterized by high efficiency and good stability. Surface temperature measurements in a porous media burner. Distributions of species concentrations and flame temperature are measured. The paper summarizes the knowledge concerning porous media combustion techniques as applied in engines. Moreover, it is essential to evaluate the conditions that lead to instability flashback phenomenon to prevent flashback in a. The typical situation envisaged is the combustion of a nondeforming porous solid medium through which a gas such as air passes. The evolution of the flame characteristics in a single injection cycle is determined from the influence of the height of the foam ceramic on the spray characteristics and the. The aim of this research is to reach an ultralean combustion, and investigate the performance of a porous burner at such condition. Combustioninporous inert media pim can take place at the poroussurfaceorwithin the porous media. Performance of domestic lpg cooking stove with porous media. Porous media combustion pmc has interesting advantages compared with free flame combustion due to higher burning rates, increased power dynamic range, extension of the lean flammability limits. From the experiment results, one can see that lowheatvalue gases are capable of stable burning in a porous media burner. In porous burner, the porous matrix recirculates heat from the postflame to the preflame zone through solid to solid radiation and conduction.
Pdf porous media combustion has been key point of interest for researchers. A wide variety of porous media have been used or suggested for porous burner applications. Twodimensional numerical simulation of combustion and. In this present work, dual layered micro burner was built with. An improved knowledge of porous burner materials design is necessary to extend the operating range to ultralean concentrations. They showed that the flame of porous burner is affected by the airflow velocity.
The pim pdf model includes the consideration of temperature deviations. A mathematical model for the gas mixture combustion in the porous medium. Apr 01, 2018 in this video, we will talk about how to calculate the porous media coefficients for a simple homogeneous porous media from the experimentally obtained velocity vs pressure loss data. Enabling tailored porous media burners via additive. Six pbsnte thermoelectric te modules with a total area of 54 cm 2 were attached to the wall of the burner.
Numerical study of the effects of porous burner parameters. This demand for energy is increasing due to population growth and rising living standard. This work reports onedimensional combustion in a porous burner using three combustion models. Twolayer porous media burner which has 140 mm length is composed of two porous sections with different porous materials. Data sheet process technology all gas porous media burner application burning of sofc anode o. Dec 17, 2018 in this study, the stable and unstable flashback phenomenon performance of a twopart porous burner has been evaluated experimentally. Burner setup figure 1 shows the porous burner and the ex perimental setup of the xct that was utilized in this study. Combustion characteristics of porous media burners under. Previous experimental investigations of different porous materials and structures yielded, that the best burner. The present study explores the utilization of a porous burner for thermoelectric power generation. The modified design called porous radiant recirculated burner which uses porous media to transfer some of the hot gas enthalpy to premixed mixture. Experimental and numerical studies of porous media combustion. The temperature of the solid phase may increase under specific conditions so that the burner adopts aradiative.
Stabilized combustion in porous media applications of. Aiaa, fluid 2000 conference and exhibition, denver, co. The porous media combustion technology is an effective solution to stable combustion and clean utilization of low heating value gas. Different suspensions have been tested, and appropriated parameters to obtain good impregnation and green strength were determined. The porous burner was tested with butane gas using two sets of configurations. Potential of porousmedia combustion technology as applied. The overall temperature of ceramic porous burner is higher than that of ceramicmetal type burner due to the lower heat storage capacity of the former, especially for the temperature downstream. Pdf performance analysis of porous radiant burners for. The paper gives an overview of possible applications of. Flame stability analysis of the premixed methaneair. Burner a is graded in porosity and constant in pore diameter pro. Stabilized combustion in porous media applications of the porous burner technology in energy and heatengineering dimosthenis trimis erlangennuernberg, univ. Experiments with combustion of diluted liquefied petroleum gases used as a fuel premixed with air are performed.
The results showed that the excess temperature is a function of the modified lewis. Experimental and numerical studies of porous media. Combustion of industrial gas in porous media burner. The burner operated with a leanpremixed methaneair mixture was mounted on a laboratory scissortype jack 2 to define the coated points coordinates. Xray computed tomography xct measurements are performed to characterize the internal volumetric flame structure within a porous media burner pmb.
A porous burner composed of a c c composite foam coated in sic has recently been developed. A baseline simulation for the three mixtures is presented. In proceedings of the fluids 2000 conference and exhibit, denver, co, june 1922, 2000, ed. However, porous burners produce less contaminant compared to others. Porous media burner pmb, working on the principle of combustion in porous media offer several advantages including high thermal efficiency, low emissions, high power intensity, etc. Co and no x emissions in porous inert media pim burner system operated under elevated pressure and inlet temperature using a new flame stabilization technique. A model of timedependent porous medium combustion is presented. Porous media in biological and environmental applications porous media for catalytic renewable energy conversion nico hotz 57 interaction of gusts with forest edges bodo ruck and michael tischmacher 63 towards a porous media model of the human lung christopher t. For observing the combustion characteristics of porous media burners under various back pressures, investigating flame stability and figuring out the distribution laws of combustion gas flow and resistance loss, so as to achieve an optimized design and efficient. Numerical simulation of a new porous medium burner with. Ansysfluent species transport combustion model tutorial for gas burner with air swirler duration. This is because combustion in inert porous media offers an interesting and promising route towards burner with highpower density, highpower dynamic range, and very low emission of pollutants such as nox and co. Experimental thermoelectric generation in a porous media. The equivalence ratio and inlet velocity are kept constant.
The latter has been studied both numerically 23, 24 and experimentally 25. Lowcalorific gas combustion in a twolayer porous burner. Experimental characterization of diesel combustion in an. Oct 21, 2015 18 comsol for solute transport in porous media duration.
In this paper, the experimental research of porous media combustion was carried on premixed combustion of multiple ejectiontangential burner, the ignition characteristic, the resistance characteristics and the temperature distribution in the burner were obtained, and the experimental results were analyzed in detailed, which can provide references for the improvements of novel porous medium. A novel liquid fuel spray and electric preheated porous media burner pmb with three flame types are investigated experimentally. Selfaspiratingairpreheating porous medium gas burner. Unlike the porous burners described in the previous section, the prrb does not operate by stabilizing the flame inside the porous medium. Perovskite catalysts for porous media in internal combustion. Analysis of thermal energy conversion into electric power. A porous media reciprocal flow burner with embedded heat. The effect of position change of porous body on combustion is studied. Straatman 69 oral session 4 nano and micro scale phenomena. Pdf co and no x emissions in porous inert media pim. Combustion in porous media is a means to alter physical and chemical mechanisms of the combustion. Porous media burner with seven coated areas and a porosity of 90%. The historical knowledge on porous inert burner and porous media in which include the. They found that the presence of surface reactions significantly influence the no x reduction efficiency.
Simple, efficient porous media minimizes environmental contamination and conserves energy resources without sacrificing performance. Experimental thermoelectric generation in a porous media burner. Potential of porousmedia combustion technology as applied to. Measurements of emissions and radiation for methane combustion within a porous medium burner. Experimental research on premixed porous media combustion in. The literature contains numerous studies of porous burners made of reticulated ceramic foams, as documented above. Porous media combustion has been key point of interest for researchers from past couple of decades due its numerous advantages, such as remarkable low emission levels without compromising thermal efficiency. Experimental and theoretical study of combustion under. The porous media reformer design presented in this study incorporates an eductor to entrain ambient air and a swirl mixing chamber and porous media bed to premix fuel and oxidizer before combustion. Investigation of lean combustion stability, pressure drop. This form of stabilisation allows a wide power and excess air ratio range. The power rate can be varied without compromising the efficiency of combustion. Enabling tailored porous media burners via additive manufacturing. The flow is turbulent due to small vortices generated by a solid porous matrix, see figure 11.
When the flame is stabilized at the porous surface,afraction of the heat released by combustion reactions is transferred to the solid phase. Porous media of lzsa glassceramic for burner applications. Combustion characteristics of blast furnace gas in porous. Longterm material durability tests at constant and cycled onoff conditions are performed, along with a characterization of combustion stability, pressure drop and pollutant emissions for a range of equivalence ratios, mass. Porous media of lzsa glassceramic for burner applications data pdf available in materials science forum 727728 august 2012 with 64 reads how we measure reads. The porous media burner of claim 1 including a nozzle part positioned in the outlet port of the casing in communication with the opening in the hollow core. The fuel mixture enters the gas distributing space between the casing and the core and then passes through the core to the hollow space of the core. Porous media combustion through a silicon carbide foam. Fabrication of porous media for porous inert burner free download as powerpoint presentation. The cartesian coordinates of these points and the burner.
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