Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
  • F23D14/38—Torches, e.g. for brazing or heating
  • F23D14/42—Torches, e.g. for brazing or heating for cutting
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
  • C10L3/00—Gaseous fuels; Natural gas; Synthetic natural gas obtained by processes not covered by subclass C10G, C10K; Liquefied petroleum gas
  • C10L3/02—Compositions containing acetylene
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
  • C21D1/34—Methods of heating
  • C21D1/52—Methods of heating with flames

Definitions

• the present invention relates, on the one hand, to a combustible gas mixture containing propane, propylene and acetylene, and, on the other hand, to a method of flame cutting a metal or a metal alloy by heating. using a flame and supply of a cutting oxygen flow.
• flame cutting uses, on the one hand, a flame of. heats and, on the other hand, a jet or flow of cutting oxygen.
• the heating flame usually fed by a mixture of combustible gas and heating oxygen, largely conditions the efficiency and quality of the flame cutting.
• the known combustible gases for feeding the heating flame are acetylene, propane, methane, hydrogen and other liquefied petroleum gases (LPG), ethylene, propylene optionally mixed with methylacetylene, or mixtures of gases such as CRYLENE TM (mixture comprising approximately 73% ethylene, 22% acetylene and 5% propylene), TETRENE TM (MAPP type mixture containing approximately 39% methylacetylene and propadiene, 44% propylene and 17% of a mixture of butane, propane and their unsaturated derivatives); TETRENE TM and CRYLENE TM are marketed by the company L'AIR LIQUIDE.
• mixtures of liquefied petroleum gas (G. P. L.), some of the constituents of which contain -OH radicals, are also used to feed an oxy-fuel flame. Mention may be made, for example, of the following combustible mixtures which are commercially available: FLAMEX TM, CHEMTANE II TM, HGX TM, OR EXCELLENE TM.
• FLAMEX TM FLAMEX TM
• CHEMTANE II TM CHEMTANE II TM
• HGX TM HGX TM
• OR EXCELLENE TM mixtures of liquefied petroleum gas
• the aforementioned sophisticated mixtures and the specific gases derived from hydrocarbons have relatively high costs, in particular of implementation, since they consume a lot of oxygen. In addition, they are often sensitive to cold and are conditioned under low pressure.
• Acetylene although making it possible to obtain high cutting speeds with good qualities of cutting edges, is poorly adapted to cuts of large thicknesses and is sensitive to flashback.
• JP-A-61042592 describes, for its part, a gas mixture of combustion for welding, heating or cutting by fusion consisting of 20 to 70% of natural gas, 10 to 60% of hydrogen and 20 to 70% acetylene.
• JP-A-50006003 teaches a liquid mixture for welding, heating or cutting metal consisting of 64 to 95% of methane and from 5 to 35% of 1 ethylene.
• document JP-A-530065303 describes a gas mixture for fusion cutting containing methane, ethylene and liquefied petroleum gas (G. P. L.), for example propane or propylene.
• document FR-A-2099217 relates to a combustible gas mixture intended for heating, melting, welding or cutting metals, containing 1 to 77% of methylacetylene and / or propadiene, methane, ethane, ethylene, propane and / or propylene.
• flame cutting is carried out by supplying the heating flame with natural gas, essentially formed of methane.
• natural gas essentially formed of methane.
• the use of natural gas for flame cutting has the advantage of using a gas whose cost is low, while making it possible to cut metallic elements over a wide range of thicknesses.
• natural gas only provides a low flame temperature, requires long preheating times and, moreover, leads to poor quality of the cutting edges.
• the object of the present invention is therefore to propose a combustible mixture, in particular for flame cutting, which does not have the drawbacks of conventional gas mixtures, which makes it possible to replace the mixtures currently used, such as CRYLENE TM and TETRENE TM, which leads to good performance, which is easy and safe to use and of reasonable cost.
• the present invention therefore relates to a combustible gas mixture containing acetylene, propane and propylene, characterized in that the ratio Qp / Qa of the proportion (Qp) of propane and propylene to the proportion (Qa) of acetylene of said mixture is such that:
• the Qp / Qa ratio is between
• 1 invention is a ternary mixture consisting of acetylene, propane and propylene and optionally containing impurities.
• the propane / propylene proportion is between 50:50 and 99: 1, preferably between 60:40 and 98: 2 preferably between 70:30 and 95: 5.
• the combustible mixture according to the invention may comprise at least one other compound chosen from nitrogen, oxygen, methane or another hydrocarbon and their mixtures.
• the combustible mixture of the invention contains from 15% to 50% by volume of acetylene, the remainder being essentially propane and / or propylene, preferably from 20 to 45% of acetylene, preferably approximately 25% to 40% acetylene.
• the fuel mixture according to the invention is preferably in gaseous form.
• the invention also relates to a welding process chosen from flame cutting, drilling in full sheet metal, brazing, heating, heat treatment and flame treatment, in particular of granites and marbles, characterized in that it uses a combustible gas mixture according to the invention.
• welding process is understood to mean a process for working with materials requiring an addition of heat delivered by a torch.
• the pressure of the combustible mixture sent to the torch is between 0.1.10 5 Pa and 5.10 5 Pa, preferably between 0.5.10 5 Pa and 2.5.10 5 Pa.
• the flow rate of said combustible mixture is between 20 lh “1 to 2000 lh “ 1 , preferably 150 lh “1 to 1000 lh “ 1 .
• the pressure and the flow rate of heating oxygen they are adjusted, in a known manner, according to the type of torch used and the desired consumption ratio.
• the invention relates to a process for manufacturing a combustible mixture containing propane, propylene and acetylene, characterized in that given proportions of acetylene, propane and of propylene, preferably mixed together, on the one hand, acetylene and, on the other hand, a propane / propylene premix, and in that one obtains a combustible mixture having the aforementioned Qp / Qa ratio .
• the combustible mixture is produced directly at the site of use, for example, by means of a mixer comprising a flow meter measuring the flow of propane and / or propylene (Qp), controlling, from this measurement of Qp, a acetylene flow regulator (Qa) and also ensuring the maintenance and / or obtaining of the desired Qp / Qa value; the mixture thus obtained is then sent to a torch.
• a mixer comprising a flow meter measuring the flow of propane and / or propylene (Qp), controlling, from this measurement of Qp, a acetylene flow regulator (Qa) and also ensuring the maintenance and / or obtaining of the desired Qp / Qa value; the mixture thus obtained is then sent to a torch.
• a combustible mixture according to the invention containing a proportion (Qa) of acetylene and a proportion (Qp) of propane and propylene such as Qp / Qa ratio is preferably equal to about 1.9 to 2.6, and containing at least 25% (by volume) of acetylene, the remainder being mainly propane and propylene, makes it possible to obtain, when it is used in an oxycut sheet process, results equivalent to those obtained with a TETRENE TM type gases and significantly better than those obtained with propane alone.
• the combustible mixture according to the invention leads to a preheating time, before cutting the sheet by adding cutting oxygen, substantially identical to that obtained with TETRENE TM, it turns out that the cutting quality is , meanwhile, significantly better than that resulting from cutting with a heating flame supplied with TETRENE TM, thanks to the presence of acetylene in high proportion compared to propane and propylene, which acetylene probably increases the heat exchange. taking place at the bottom of the groove between the flame and the workpiece.
• the following tests aim to determine the evolution of the priming time in full sheet metal for a cutting torch as a function of the proportion of acetylene in the fuel supply mixture; the remainder of the mixture being propane and propylene, and possibly common impurities.
• the propane used contains a few% of propylene, typically about 1 to 5%, but, for the sake of simplification, we speak below only of propane while bearing in mind that it it is in fact a propane / propylene mixture, the proportion of propane being much higher in this case than that of propylene.
• the measurement on the priming time that is to say the time necessary to bring the sheet to the cutting temperature (about 1,300 ° C.) from ambient temperature, the priming time being defined experimentally as being the time minimum heating which allowed to obtain a cutting initiation of the sheet during the supply of cutting oxygen.
• a series of tests is in fact carried out, during which the test pieces are initially heated with the same gas mixture at room temperature for different periods of time.
• the priming time is determined which is the minimum period of time which gave rise to a priming, that is to say at the beginning of combustion of the test piece in the oxygen jet.
• the cutting head is of the MACH 3S PROPANE type
• the cutting head is of type MACH 3S TETRENE.
• the priming time is an inverse function of the acetylene content of the mixture.
• a time saving of 30 to 42% is obtained for a mixture composed of 70% propane and 30% acetylene, which increases with the content 10
• acetylene in the combustible mixture makes it possible to obtain a luminous flame and the morphology of the dart and the plume facilitates the adjustment of the consumption ratio of the torch compared to its use powered only by propane and propylene. .
• acetylene added to propane and propylene increases the flame temperature and improves the quality of the cutting edges.
• acetylene provides only a short flame length
• the mixture of acetylene and propane and propylene makes it possible to obtain a flame having a longer length, which makes it possible to cut out elements of strong thickness.
• the mixture of propane, propylene and acetylene with Qa / Qp ⁇ 2.30 approximately and containing approximately 30% acetylene is advantageously usable in applications of welding, surface quenching, heating, shrinking or thermal spraying.
• this mixture is versatile and can be used for all of the applications implemented, for example, by a boilermaker or a metal carpenter.
• the combustible mixture according to the present invention is particularly well suited for use in an oxycutting process of metals, such as steels, in particular non-alloyed or low-alloyed steels, as defined in particular in the document AFNOR N ° FD CR 12187.1995. F; April 1996.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Organic Chemistry (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• General Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Combustion & Propulsion (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Insulated Conductors (AREA)
• Liquid Carbonaceous Fuels (AREA)

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Family Cites Families (5)

• 1998
  • 1998-02-12 FR FR9801674A patent/FR2774693B1/fr not_active Expired - Fee Related
• 1999
  • 1999-01-28 WO PCT/FR1999/000165 patent/WO1999041340A1/fr not_active Application Discontinuation
  • 1999-01-28 EP EP99901642A patent/EP1053292A1/de not_active Withdrawn
  • 1999-01-28 AU AU21678/99A patent/AU2167899A/en not_active Abandoned

Non-Patent Citations (1)

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