FR2501712A1 - STABLE DENSITY STABLE TERNARY CRYOGENIC FUEL WITH LOW GAS STATE - Google Patents

Abstract

1. Stable ternary cryogenic combustible with a gas phase density lower than that of air, consisting of a mixture of acetylene, ethylene, and hydrocarbon containing 3 carbon atoms per molecule, characterized in that the said initial cryogenic mixture contains 25 to 30 percent by volume of acetylene, 61 to 72 percent by volume of ethylene, and 3 to 9 percent by volume of the C3 -hydrocarbon.

Description

"STABLE TERNARY CRYOGENIC FUEL WITH DENSITY IN THE GASEOUS STATE"

LOWER IN THE AIR "2501712

  Invention of Maurice BRUNI and Georges DUBOZ.

  oi i: d TO THE, RLIDOCIET ANONYMOUS FOR STUDY

  Y E? X $ tOl18 É & EDESEOR USI CEÀU E.

  The present invention relates to a tertiary fuel

  stable density In the gaseous state below the

density of the air.

  It has been customary for more than half a century to use acetylene in this technical field. However, the nature of acetylene makes it very dangerous to keep it compressed in its natural state, and is usually stored after being compressed and dissolved in a solvent, such as acetone, in a porous material. . In these conditions,

  1n in relation to the weight of the container and its contents the quantity

  The amount of acetylene stored or transported is low.

  The transport and storage of acetylene in the liquid state has been considered, however, because of the risk of explosion and the difficulty of handling, acetylene

pure liquefied is not used.

  The use of acetylene mixtures has been proposed, avoiding the risk of explosion and making it possible to obtain

  a sufficiently high combustion temperature to

  perform welding and cutting operations. Else

  It is known that the addition of acetylene in a

  The fuel can give the latter welding performance tending towards those of acetylene. if it is easy to produce gas mixtures with a constant composition, it is not the same when the mixture comes from a storage in the liquid state where the gas phase is different, in composition, from the phase liquid. In the case of the ethylene-acetylene mixture an enrichment in

  acetylene, whereas in the case of propylene-acetylene

  tylene there is depletion in acetylene, which leads,

  after a while, has a mixture unfit for soldering.

  This difficulty could be avoided by

  removal of the liquid phase of the mixture which remains constant,

  since the liquid does not heat up too much.

  In industry, in general, reheating,

  liquid can not be avoided and we are obliged to

  cull the excess pressure which creates a modification

  of the mixture. This phenomenon is very important when

  the container is bad or the cryogenic container

  gene has been stored too long.

  For several years, fuel mixtures with a substantially constant content of acetylene have been sought which do not require special equipment for its distribution in liquid, as is the case for ethylene-acetylene mixtures. Distributable mixtures were found

  in liquid form with conventional equipment

  cryogenic substances and whose gaseous phase and phase

  liquid have a substantially constant content of acetylene.

  These combustible gas mixtures obtained by natural evaporation of the liquid phase, without sampling thereof,

  represent for the user an economy of investment

  because of a simplification of the equipment by

  binary ethylene-acetylene binary mixtures.

  With the known ethylene-acetyl ether mixtures

  preferential evaporation of the ethylenic compound and consequently enrichment of the liquid phase in acetylene is observed. The proposed ternary mixtures which have only low enrichment in acetylene,

  better meet the safety criteria.

  Mixtures of two hydrocarbons were obtained

  and acetylene which, by natural evaporation,

  kill a gas whose acetylene content varies little, especially if using a conventional cold evaporator allowing the simultaneous sampling of the liquid and gaseous phase, producing three-component mixtures in which a component is more volatile than acetylene while the third is less so. The latter constituent contributes by physical effect to the stabilization of the phase

  at the end of emptying, while the most volatile

  Read the gas phase, especially at the beginning of the emptying.

  The constituent more volatile than acetylene

is ethylene.

  The third constituent chosen so as to cause the stabilization of the liquid phase is a

  hydrocarbon whose molecule contains three carbon atoms

  bone, the said hydrocarbon forming part of the group consisting of propane, cyclopropane and propylene and the choice

250 1 7 1 2

  preferably bearing on the unsaturated hydrocarbon.

  In addition, to meet the criteria

  particular safety requirements for all work carried out

  killed in confined-atmosphere premises and workshops, located below ground level, cramped, sometimes difficult to ventilate, combustible mixtures for welding and

  the gaseous state remains lower than that of the air.

  According to the invention, the ternary fuel

  cryogenic mixture consisting of a mixture of ethylene acetylenes

  ne and a hydrocarbon in C in the following proportions s

  at 30% acetylene, 61 to 72% by volume of ethyl

  and 3 to 9% by volume of the C 3 hydrocarbon is used in the gaseous state after vaporization of the mixture

stored in the liquid state.

  This combustible mixture is particularly

  suitable for welding and assembly operations.

  The density in the gaseous state is always

  less than that of air, even when performing a pre-

  alternation of the gaseous phase of the storage tank

  or liquid vaporization, under normal operating conditions, ie when, at the

  maximum, the ratio of the quantity withdrawn in the gas phase

  to that taken by the liquid phase, remains lower

to 1.

  The stability of the fuel mixture is

  suitable for industrial use in large quantities.

  The low enrichment of acetylene, during a slow evaporation, allows the distribution of said mixtures in bulk or in small conventional cryogenic evaporators, free of copper or copper alloys. Transport and transfer are more

  advantageously produced, the product being in the liquid state.

  It is possible to envisage the conditioning of the gaseous phase in the compressed state, under a pressure of up to 100 bar,

  in containers filled with porous material.

  The combustible mixtures of the invention,

  when the C3 hydrocarbon is propylene, are

  in the attached ternary diagram in the figure

  1. The contents of acetylene, ethylene and propylene are

  in percentages by volume. The density properties

  The lower gas phase and low acetylene enrichment are perfectly preserved in the quadrilateral A 'B' C 'D' located below the right

  FG representing the mixtures of density equal to the air.

  The preferred field of use is

  to a cryogenic mixture containing about 26% acetylene, about 69% ethylene and about 5% propylene. An illustrative example is given below

the invention without limitation.

Example

  Initial composition E acetylene 26% ethylene 69% propylene 5% The use of this mixture in

  conventional evaporators, from which it is possible

  the ability to withdraw the liquid phase and the gas phase as a function of the increase in the pressure of the reservoir, gives rise to the modification of the following compositions:

  In any case, we can see on the

  FIG. 2 shows that all the points appearing in the liquid and gaseous compositions are below the line G / F in the appended drawing. Dashed line "" shows the evolution of% Weight gas phase Liquid phase of emptying acetylene ethylene propylene acetylene ethylene propylene, starting 21.0 77.0 2.0 26.0 69, o 590% 21.5 76.5 2 , 0 26.5 68, o 505

% 22.0 75.5 2.5 27.0 67.0 6.0

% 22.5 74.5 3.0 27.5 63.5 9.0

% 24.0 72.5 3.5 29.5 59.5 11.0

250 1 7 12

  the liquid phase while the dotted line E'E "cor-

  corresponds to that of the gaseous phase. The original cryogenic mixture is represented by the point E, the conjugate point E 'representing the composition of the gaseous phase in

  balance with E; the points E "and E" 'representing respectively

  the compositions of the gas phase and the

liquid phase at 80% emptying.

Claims (6)

  1. Stable cryogenic ternary fuel   density in the gaseous state lower than that of air,   titué by a mixture of acetylene, ethylene and hydrocarbon   containing three carbon atoms in its molecule, which is   characterized in that said initial cryogenic mixture contains 30% by volume of acetylene, 61 to 72% by volume of ethylene and 3 to 9% by volume of C-hydrocarbon.   2. Ternary fuel according to the claim   1, characterized in that the hydrocarbon containing three carbon atoms is part of the group consisting of   propane, cyclopropane and propylene.   3. Ternary fuel according to the claim   1, characterized in that the C 3 hydrocarbon is propylene.   4. Ternary fuel according to the claim   3, characterized in that the initial cryogenic mixture contains about 26% acetylene, about 69% ethylene and about 5% propylene.   5. Ternary fuel according to any   claims 1 to 4, characterized in that the said   fuel is stored in the refrigerated liquid state and used   in the gaseous state after vaporization.   6. Ternary fuel in the gaseous state   composition according to any of claims 1 to   4, characterized in that said gaseous fuel is   compressed state under pressure which can reach   dre up to 100 bar in containers filled with porous material.