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COMBUSTION OF GASEOUS FUELS COMBUSTIBLE MIXTURE TYPES OF COMBUSTIBLE MIXTURES FLAMMABILITY LIMITS - FLAMMABILITY LIMITS: Definition - LEAN AND RICH FLAMMABILITY LIMITS - EXPLOSION LIMIT - FLAMMABILITY LIMITS: examples IGNITION - IGNITION PHENOMENA - MINIMUM ENERGY of IGNITION - MINIMUM IGNITION ENERGY OF GASES - SELFIGNITION PROPAGATION OF COMBUSTION - Deflagration -FLAME - FLAME STRUCTURE - LAMINAR AND TURBULENT FLAMES - PREMIXED AND DIFFUSION FLAMES - Detonation - Glow ....
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RENALT ENERGY
By Gerard B. Hawkins Executive Director
A Business Unit of GBH Enterprises, Ltd. www.renaltenergy.com
Renewable and Alternative Energy for the New Millennium
RENALT ENERGY
COMBUSTIBLE MIXTURE
A Business Unit of GBH Enterprises, Ltd. www.renaltenergy.com
Definition: a mixture of fuel and oxidizer is combustible when combustion is developing in it after an ignition source vanishes.
RENALT ENERGY TYPES OF COMBUSTIBLE MIXTURES
A Business Unit of GBH Enterprises, Ltd. www.renaltenergy.com
RENALT ENERGY
FLAMMABILITY LIMITS
A Business Unit of GBH Enterprises, Ltd. www.renaltenergy.com
RENALT ENERGY FLAMMABILITY LIMITS: DEFINITION
A Business Unit of GBH Enterprises, Ltd. www.renaltenergy.com
Flame can occur only in mixture within a certain composition range: flammability limits.
Flammability limits refer to the composition range within which ignition and flame propagation can be brought by external ignition (e.g. by spark).
RENALT ENERGY
LEAN AND RICH FLAMMABILITY LIMITS
A Business Unit of GBH Enterprises, Ltd. www.renaltenergy.com
LFL – minimum percentage of fuel by volume in the mixture RFL – maximum percentage of fuel by volume in the mixture
(for solid fuels could be expressed in g/m3)
RENALT ENERGY
EXPLOSION LIMIT
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Explosion limits mean the same as flammability limits: LEL – lower explosion limit means the same as lean flammability limit. UEL – upper explosion limit means the same as rich flammability limit.
RENALT ENERGY FLAMMABILITY LIMITS: EXAMPLES
A Business Unit of GBH Enterprises, Ltd. www.renaltenergy.com
RENALT ENERGY
IGNITION
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Definition: Ignition means local initiation of the combustion process in a combustible mixture.
RENALT ENERGY
IGNITION PHENOMENA
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Two ignition types can be distinguished: -external ignition (e.g. spark ...),
- selfignition
RENALT ENERGY
MINIMUM ENERGY of IGNITION
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Two ignition types can be distinguished: E min – is minimum of energy, which discharged in a combustible mixture causes it’s ignition. E min – is measured in J.
RENALT ENERGY MINIMUM IGNITION ENERGY OF GASES
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RENALT ENERGY
SELFIGNITION
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RENALT ENERGY
PROPAGATION OF COMBUSTION
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1. Deflagration
2. Detonation 3. Glow
RENALT ENERGY
DEFLAGRATION
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1. Deflagration is propagation of a combustion process by flame. 2. Mechanism of propagation has thermal character: by heat conduction.
RENALT ENERGY
FLAME
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RENALT ENERGY
DETONATION
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RENALT ENERGY
FLAME STRUCTURE
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RENALT ENERGY
LAMINAR AND TURBULENT FLAMES
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RENALT ENERGY
PREMIXED AND DIFFUSION FLAMES
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Considering preparation of combustible mixture there are two principal types of flames: - premixed, - diffusion flames.
RENALT ENERGY
FLAMES
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RENALT ENERGY PREMIXED LAMINAR FLAME
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RENALT ENERGY
STRUCTURE OF PREMIXED LAMINAR FLAME
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RENALT ENERGY
STRUCTURE OF PREMIXED LAMINAR FLAME
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RENALT ENERGY
SPEED OF PREMIXED, LAMINAR FLAME
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RENALT ENERGY
PREMIXED, LAMINAR FLAME ABOVE THE BUNSEN BURNER
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RENALT ENERGY
PREMIXED, LAMINAR FLAME ABOVE THE BUNSEN BURNER
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RENALT ENERGY
STRUCTURE OF DIFFUSION, LAMINAR FLAME
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RENALT ENERGY
STRUCTURE OF DIFFUSION, LAMINAR FLAME
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RENALT ENERGY
STRUCTURE OF DIFFUSION, LAMINAR FLAME
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Diffusion flame height vs. gas outflow velocity
RENALT ENERGY
LIMITED DIFFUSION, TURBULENT FLAME
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Lifted diffusion flame
turbulization
RENALT ENERGY
TURBULENT FLAME
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Surface area of turbulent flame
RENALT ENERGY
STRUCTURE OF DIFFUSION,TURBULENT FLAME
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RENALT ENERGY
INFLUENCE OF TURBULENCE ON FLAME STRUCTURE
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RENALT ENERGY
STABILITY OF GAS FLAMES
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Stability of premixed flame in an open space
RENALT ENERGY
GAS BURNERS
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RENALT ENERGY REQUIREMENTS FOR GAS BURNERS
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Features of good burner: - stable and proper operation in the range of design parameters, - low emission of pollutant, - security of operation - long lifetime, - low level of noise.
RENALT ENERGY
TYPES OF GAS BURNERS
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RENALT ENERGY CLASSIFICATION OF GAS BURNERS DEPENDING ON APPLICATIONS
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•Compact burners (common use) •Low- emission burners •Start-up burners •Pilot burners •Special burners
RENALT ENERGY
PRINCIPLE OF OPERATION OF LOW-PRESSURE JET-EJECTOR GAS BURNER
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RENALT ENERGY RANGE OF OPERATION LOW-RESSURE
JET-EJECTOR GAS BURNER
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RENALT ENERGY
SELECTION OF NOZZELS FOR LOW-RESSURE JET-EJECTOR GAS BURNERS
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RENALT ENERGY
EXAMPLES OF LOW-RESSURE JET-EJECTOR GAS BURNERS
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RENALT ENERGY
LOW-RESSURE JET-EJECTOR GAS BURNERS
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Domestic ovens burners
RENALT ENERGY
HIGH-RESSURE JET-EJECTOR GAS BURNERS
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RENALT ENERGY
NOZZLE-MIX JET BURNERS
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RENALT ENERGY NOZZLE-MIX SWIRL BURNERS
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RENALT ENERGY
COMPACT BURNER
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RENALT ENERGY
DUCT BURNER - IDEA
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RENALT ENERGY DUCT BURNERS - SOLUTIONS
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RENALT ENERGY
WASTE GAS BURNER
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RENALT ENERGY
RADIATING TUBES
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RENALT ENERGY
GAS FLARES
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RENALT ENERGY
PILOT BURNERS
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RENALT ENERGY
GAS LAMPS
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RENALT ENERGY
NEW COMBUSTION TECHNOLOGIES: FLAMELESS
COMBUSTION
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•Diluted combustion •Highly preheated combustion
RENALT ENERGY
FLAMELESS COMBUSTION
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flame combustion
flameless combustion
RENALT ENERGY
CONDITIONS OF FLAMELESS COMBUSTION
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temperature of air must be higher than selfignition temperature (800-1000 o C), intensive recirculation in flame region should secured,
burning at low oxygen concentration, below 2-5 % vol.,
system of air and gas nozzles should allow to extend the combustion process on the whole furnace.
RENALT ENERGY RULES OF FLAMELESS COMBUSTION
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T pow – air temp. T procesu – process temp.
RENALT ENERGY RANGE OF FLAMELESS COMBUSTION
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RENALT ENERGY
EFFECTS OF FLAMELESS COMBUSTION
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increase of thermal efficiency, saving of fuel: 15-30%, increase of furnace capacity: 25%,
uniform temperature distribution in the furnace, low NOx concentration in flue gas
an order lower than using low-NOx combustion systems, two orders lower than using conventional burners.
RENALT ENERGY NOx CONCENTRATION IN FLUE GAS DEPENDING ON THE TEMPERATURE
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1- conventional burner, 2- air staging, 3- flameless combustion
RENALT ENERGY APPLICATION OF FLAMELESS
COMBUSTION TECHNOLOGY
A Business Unit of GBH Enterprises, Ltd. www.renaltenergy.com
At present: In glass industry (burners of 200-300kW), In ceramic industry (burners of 200-300kW), In metallurgy (burners of 6-8 MW), In petrochemistry. In the future: In power plants (PF boilers), In the waste incinerators.
RENALT ENERGY Renewable and Alternative Energy for the New Millennium
"RENALT ENERGY" - providing integrated solutions to "Green" petrochemicals, integrated Bio-Refining /conventional oil Refining, and Biomass-to-chemicals, primarily through Energy and Process Consultancy. Biomass-to-"Green" chemicals: Biomass-to-chemicals refers to the process of producing chemicals from Biomass. The major Biomass -to-chemicals processes utilized in worldwide, with our strategic focus on, Biomass-to-methanol, MTO and MTP processes that produce the same chemical products, such as ethylene and propylene, as the petrochemical facilities, due to better cost efficiencies and greater demand for these chemicals.
www.renaltenergy.com
RENALT ENERGY Renewable and Alternative Energy for the New Millennium
We also have interest in, Biomass-to-olefins, Biomass-to-PVC, Biomass to-aromatics and Biomass-to-ammonia/urea processes. We provide a broad range of integrated services spanning the project life-cycle from feasibility studies, consulting services, provision of proprietary technologies, design, engineering, and after-sale technical support.
Executive Director GBH Enterprises, Ltd. RenAlt Energy Office: +1-312-235-2610 Cell: +52 55 2108 3070 [email protected] www.renaltenergy.com
www.renaltenergy.com