COMBUSTION OF GASEOUS FUELS

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

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COMBUSTIBLE MIXTURE


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


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FLAMMABILITY LIMITS


RENALT ENERGY FLAMMABILITY LIMITS: DEFINITION


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).

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LEAN AND RICH FLAMMABILITY LIMITS


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)

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EXPLOSION LIMIT


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


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IGNITION


Definition: Ignition means local initiation of the combustion process in a combustible mixture.

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IGNITION PHENOMENA


Two ignition types can be distinguished: -external ignition (e.g. spark ...),

- selfignition

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MINIMUM ENERGY of IGNITION


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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SELFIGNITION


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PROPAGATION OF COMBUSTION


1. Deflagration

2. Detonation 3. Glow

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DEFLAGRATION


1. Deflagration is propagation of a combustion process by flame. 2. Mechanism of propagation has thermal character: by heat conduction.

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FLAME


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DETONATION


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FLAME STRUCTURE


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LAMINAR AND TURBULENT FLAMES


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PREMIXED AND DIFFUSION FLAMES


Considering preparation of combustible mixture there are two principal types of flames: - premixed, - diffusion flames.

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FLAMES


RENALT ENERGY PREMIXED LAMINAR FLAME


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STRUCTURE OF PREMIXED LAMINAR FLAME


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SPEED OF PREMIXED, LAMINAR FLAME


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PREMIXED, LAMINAR FLAME ABOVE THE BUNSEN BURNER


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STRUCTURE OF DIFFUSION, LAMINAR FLAME


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STRUCTURE OF DIFFUSION, LAMINAR FLAME


Diffusion flame height vs. gas outflow velocity

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LIMITED DIFFUSION, TURBULENT FLAME


Lifted diffusion flame

turbulization

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TURBULENT FLAME


Surface area of turbulent flame

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STRUCTURE OF DIFFUSION,TURBULENT FLAME


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INFLUENCE OF TURBULENCE ON FLAME STRUCTURE


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STABILITY OF GAS FLAMES


Stability of premixed flame in an open space

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GAS BURNERS


RENALT ENERGY REQUIREMENTS FOR GAS BURNERS


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.

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TYPES OF GAS BURNERS


RENALT ENERGY CLASSIFICATION OF GAS BURNERS DEPENDING ON APPLICATIONS


•Compact burners (common use) •Low- emission burners •Start-up burners •Pilot burners •Special burners

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PRINCIPLE OF OPERATION OF LOW-PRESSURE JET-EJECTOR GAS BURNER


RENALT ENERGY RANGE OF OPERATION LOW-RESSURE

JET-EJECTOR GAS BURNER


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SELECTION OF NOZZELS FOR LOW-RESSURE JET-EJECTOR GAS BURNERS


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EXAMPLES OF LOW-RESSURE JET-EJECTOR GAS BURNERS


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LOW-RESSURE JET-EJECTOR GAS BURNERS


Domestic ovens burners

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HIGH-RESSURE JET-EJECTOR GAS BURNERS


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NOZZLE-MIX JET BURNERS


RENALT ENERGY NOZZLE-MIX SWIRL BURNERS


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COMPACT BURNER


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DUCT BURNER - IDEA


RENALT ENERGY DUCT BURNERS - SOLUTIONS


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WASTE GAS BURNER


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RADIATING TUBES


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GAS FLARES


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PILOT BURNERS


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GAS LAMPS


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NEW COMBUSTION TECHNOLOGIES: FLAMELESS

COMBUSTION


•Diluted combustion •Highly preheated combustion

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FLAMELESS COMBUSTION


flame combustion

flameless combustion

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CONDITIONS OF FLAMELESS COMBUSTION


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


T pow – air temp. T procesu – process temp.

RENALT ENERGY RANGE OF FLAMELESS COMBUSTION


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EFFECTS OF FLAMELESS COMBUSTION


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


1- conventional burner, 2- air staging, 3- flameless combustion

RENALT ENERGY APPLICATION OF FLAMELESS

COMBUSTION TECHNOLOGY


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

COMBUSTION OF GASEOUS FUELS

Technology

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