US2925384A - Process of storing and handling acetylene solutions - Google Patents

Description

United States Patent PROCESS OF STORING AND HANDLING I ACETYLENE SOLUTIONS Karl Winnacker, Konigstein, and Arthur Wolfram, Frankfurt, Germany, amignors to Knapsack-Griesheim Alttlengesellschaft, Knapsack, near Koln, Germany, a company of Germany No Drawing. Application November 29, 1955 Serial No. 549,855

Claims priority, application Germany February 14, 1951 7 Claims. (Cl. 252-4) This application is a continuation-in-part application of our application Ser. No. 271,076, now abandoned, which describes the storage or transportation of liquid acetylene which is dissolved at a temperature below -80 C. in at least one solvent for acetylene, for example acetaldehyde. The solvent being present in an amount of at least about 22 percent calculated upon the weight of the acetylene.

The present invention relates to the safe handling, storing or transporting of liquid acetylene and comprises storing and handling acetylene at temperatures below about -80 C. and dissolved in at least one solvent for acetylene with the solvent being present in an amount of at least about 22 percent calculated upon the weight of the acetylene solution. The solutions of acetylene in mixtures of solvents are new. They are likewise an object of the present invention.

We have found that acetylene can safely be handled, stored and transported in the liquid state in the form of solutions which are obtained by introducing gaseous acetylene at a temperature below about -80 C. into a solvent mixture capable of readily dissolving the acetylene and consisting of acetaldehyde and methyl isobutyl ketone and/or methyl ethyl ketone and additionally of acetone.

Since acetylene, and particularly liquid or solid acetylene, belongs to the class of violently explosive compounds, it cannot be stored as other hydrocarbons under pressure in steel bottles unless these steel bottles contain a filling material and the acetylene is compressed into a solvent such as acetone. Such acetylene, designated as dissolved acetylene gas, possesses the disadvantage that only a relatively small quantity may be stored in a bottle and that a large and expensive stock of bottles must therefore be maintained. Considerable expense occurs through frequent and requiredrepairs to the steel bottles and the valves. Many attempts have already been made to convert the acetylene into the solid form and to store it is that form, but this has been impossible in practice in view of the explosive property of the product. According to another suggestion, the liquid acetylene should be stored in a fully enclosed pressure reservoir cooled by means of solid carbon dioxide and acetone. This process is not satisfactory for industrial purposes because it is too dangerous.

The solvent mixtures used according to the present invention are liquid at temperatures between about --80 C. and about -1'15 C. The components of said mixtures have a boiling point above 0 C.

If the process of this invention shall be economical, the amount of the solvent used must be as small as possible. Hence, it is necessary to employ temperatures as low as possible. It is generally satisfactory that about two and a half to three and a half times the quantity by weight of acetylene be present with respect to the weight of the solvent or solvents, i.e. the solvent or solvents must be present at least in a quantity of about 22 percent, calculated upon the weight of the acetylene solution.

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Preferably the solvent represents about 25-50% by weight of the acetylene solution and the optimum amount of solvent is about 25-33%. The acetylene is preferably present in an amount of at least about 50% and preferably about 67 to especially 70% or more. However, it has been found that acetylene crystals may separate from very cold solutions whereby the danger of explosion is highly increased.

According to the present invention, it is now possible to transport or to store large quantities of acetylene for a prolonged time, since a solution of acetylene cooled to about -1l0 C. can be stored far longer in the liquid state than a solution of a higher temperature. If the melting point is, for example, at l40 C., the temperature of the acetylene solution may rise for 60 degrees centigrate, but the explosion-proof character of the solution is still maintained. For economical reasons, however, extremely low temperatures will be applied for the preparation of the cooled solutions only exceptionally since, when solvents are used which at about 1l5 C. are just still liquid, the solutions have a sufiiciently large capacity to maintain a temperature below C., which temperature is necessary for storing or transporting. Also, the costs increase as the temperature of the solvent is lowered when preparing the acetylene solution. The dissolved liquid acetylene cooled e.g. to temperatures of about l15 C. can be transported or stored for many days in a well insulated vessel without undergoing a loss of acetylene and solvent worth mentioning. This amounts to a considerable saving in comparison with the hitherto known processes. The transport of the dissolved acetylene is thus made bearable from an economical point of view, and this the more so, since simple, well insulated reservoirs having relatively thin walls may be used. Neither during the manufacture of the dissolved liquid acetylene is an application of pressure necessary, nor is a pressure produced in an amount worth mentioning during the storing at a temperature of about -80 C. or below. If it is intended to store the dissolved, liquid acetylene for a prolonged period, it is recommended to apply a refrigeration by means of a corresponding cooling agent. If vessels having thick walls are applied, it is, of course, also possible to dissolve the acetylene with application of pressure. The application of pressure is, however, not necessary. It is also possible to maintain the solutions of liquid acetylene even under reduced pressure, but above the boiling point of acetylene. However, this procedure is not very economical.

If the solvent boils at a sulficiently high temperature, for instance at 0 C., it is also possible, when the gaseous acetylene is eventually used, to obtain a gas, substantially free from solvent. The solutions according to this invention consist of acetylene and at least 22 percent (calculated on the weight of the solution) of a solvent mixture, comprising at least 70 percent and at most 99.5 percent of acetaldehyde.

The mixtures of solvents used according to the present invention contain at least about 70 percent and at most 99.5 percent of acetaldehyde. The remaining parts consist of methyl ethyl ketone and/0r methyl isobutyl ketone in an amount of about 0.5 to about 25 percent and of acetone in an amount of about 0.1 to about 15 percent, the percentage data being calculated on the total amount of the solvent mixture in which the acetylene will be dissolved.

It is to be understood that where solvent mixtures are described in which the total amount of the upper limits of all percentage figures oi the solventsother than acetaldchyde is higher than 30"percent, the total amount of these components in the solvent mixture shall be not higher than 30 percent.

Preferably, mixtures are used of about 70 to about 98.9 percent of acetaldehyde, of about 1 to about 22 percent of methyl ethyl ketone and/or methyl isobutyl ketone and of about 0.1 to about 15 percent of acetone. Furthermore, it has been found suitable to use mixtures of solvents which contain at least about 70 and at most about 99.3 percent of acetaldehyde, between about 0.1 to about 15 percent of acetone, between about 0.5 to about 20 percent of methyl ethyl ketone and between about 0.1 and about 8 percent of methyl isobutyl ketone. Other mixtures of solvents which can be used are those which contain between about 70 and about 99 percent of acetaldehyde, between about 0.4 and about 8 percent of acetone, between about 0.5 and 20 percent of methyl ethyl ketone and between about 0.1 to about 8 percent of methyl isobutyl kctone; the total amount of methyl isobutyl ketone being never higher than about 25 percent.

Especially suitable are solvent mixtures which contain between about 70 and about 90 percent of acetaldehyde" and in which the total amount of the other components is between about 10 and about 30 percent, every component itself being added in an amount within the limits given above.

The mixtures of this invention are capable of readily dissolving the acetylene and are still liquid at temperatures between about 115 C. to --80 C. They yield solutions of acetylene which are still liquid at very low temperatures and in many cases at far lower temperatures than those described in the parent application.

It is desirable to keep as low as possible the temperature at which a solidification of the acetylene dissolved in the solvent or in the mixtures of solvents occurs, since the solidified solution or a solution containing acetylene crystals can no longer be handled with complete safety. Already with some solvents, for instance, acetaldehyde, it is possible to obtain solutions which solidity only-at a temperature considerably below --80 C. With the mixtures of solvents as described in the present 'applb cation, the solidification point is, in general, pressed down to a lower degree. The quantitative proportion of the various solvents in these mixtures may vary within the wide limits mentioned above. It is particularly suitable to use the various constitutents in such quantities that eutectic mixtures are formed.

The quantitative proportions in which the solvents or the mixtures of solvents on the one hand and the acetylene on the other hand shall be used may likewise vary to a large extent. The quantity of the solvent or of the mixtures of solvents may be superior to that of the acetylene.

Since the acetylene from the solution may be used directly for filling bottles of dissolved acetylene gas, it is advisable, during the manufacture of the acetylene solution, to use a well purified acetylene, in order to avoid a purification at a later date. If, the steps described herein are strictly observed, the solutions of liquid acetylene will not detonate with the detonators usually applied in explosive tests.

With the mixtures of acetylene and solvents described in Examples l-14 hereafter, detonation tests were made. Furthermore, the said mixtures were subjected to tests which consisted in severely heating the solution contained in a nearly sealed metal tube. The metal tube of a length of about 40 centimeters and containing 1 liter of the solution, was heated in a slightly inclined position with 6 strong Teclu burners. The acetylene with the solvent was permitted to escape through an aperture of a diameter of 1.5 millimeters at one extremity of the tube and burnt ofi merely with a strong flame, whereas meta-dinitrobenzene detonated when tested in the same manner. It must be emphasized that meta-dinitrobenzene is not regarded as an explosive for purposes of transport.

The industrial progress attained by the process of the present invention is thus proved.

The following examples serve to illustrate flie'invention,

4 but they are not intended to limit tberetqtheparts being by weight:

Example I grams of the mixgrams of percent turn of dlssol'vsd my weight. s n 64 (hi1: without acetylene lound melting p i t. C.

(2) 10.0 percent methyl ethyl ketoue+6.0 percent acetoilet-81.0 percent acetatdehyde (3) 10.0 percent methyl ethyl ketonu+3.0 percent acetone+8L0 percent ucetaldebyde (4) 20.0 percent methyl ethyl immune-1.0 percent acet.0ue+79.9 percent acuteldehyde (5) 20.0 percent methyl ethyl ketouo-I-7.0 percent ace tone +73;0 percent acetatdehydc (0% 2.0 percent methyl isoutyl kctoie-l-ton percent; ao3tone+83.0 percent neataliehyde (7) 14.0 percent methyl lso butyl ketone t-iupercent acetune+82.0 perceutaceb alzleh d y 15:2 (8) 20.0 percent -10; methyl isobutyl ketone+L0 percent acetone-H911 percent acetaldeiyde (9) 2.0 percent methyl ethyl kotone +1.0 percent methyl isobutyl ketone+l3.0 percent acetone+84.0 percent acetaldehyde (in) 12.0 percent methyl ethyl ketone+2.5 percent methyl lsobutyl ketone +2.5 percent scratched-83.0 percent acetaldehyde V (11) 20.0 percent methyl .eths l ketone+0.5 percent methyl lsobutyl ketone +0.5-perouut acetone-Mao poreenbacetaldehyde (13012.0 percent methyl ethyl ketone+20 percent methyl tsooutyl ketone +3.0 percent costumes-83.0

ercen't acetaldehyde (I ).15.0 percent methyl ethyl ketonc+L5 percent methyl lsobutyl ketone +45 percent acet0ne+79.0 percent acct-aldehyde a (14) 19.0 percent methyl ethyl ketoue+0.5 percent methyl lsobutyl ketone +6.5 percent acetone-+740 percent acetaldehyde 15.8 3&1 0 -l05 We claim:

1. The process of storing and handling acetylene solutions with a high concentration or at'le'ast 50% anemone at low temperature at substantially normal pressure for prolonged periods of time without danger of explosion which comprises dissolving, storing and handling acetylene at temperatures below about C. in a mixture of solvents for acetylene, which consists or about 70 to about 99.4 percent assessment as, aboutQS to abo'ut 2.5 percent of a ltctone selected from the" group consisting of methyl ethyl ketone and methyl isobutyl ketone and mixtures thereof and of about 0.1 to about IS percent of acetone, said mixture of solvents'being presem'in an amuunt'of'between about 22 and 50 percent calculated on the weight of the acetylene solution, and the solution being maintained above the solidification point.

2. The process of storing and handling acetylene solutions with a high concentration of at least 50% acetylene lat low temperature at substantially normal pressure for prolonged periods of time without danger of explosion which comprises dissolving, storing and handling acetylene at temperatures below about 80 C. and under substantially atmospheric pressure in a mixture of solvents for acetylene, which consists of about 70 to about 99.4 percent of acetaldehyde, about 0.5 to about 25 percent of a ketone selected from the group consisting of methyl ethyl ketone and methyl isobutyl ketone and mixtures thereof and of about 0.1 to about 15 percent of acetone, said mixture of solvents being present in an amount of between about 22 and 50 percent, calculated on the weight of the acetylene solution, and the solution being maintained above the solidification point.

3. The process of storing and handling acetylene solutions with a high concentration of at least 50% acetylene at low temperature at substantially normal pressure for prolonged periods of time without danger of explosion which comprises dissolving, storing and handling acetylene at temperatures below about 80 C. in a mixture of solvents for acetylene, which consists of about 70 to about 99.3 percent of acetaldehyde, about 0.1 to about 15 percent of acetone, about 0.5 to about 20 percent of methyl ethyl ketone and of about 0.1 to about 8 percent of methyl isobutyl ketone, the total amount of methyl ethyl ketone and methyl isobutyl ketone being not higher than about 25 percent, said mixture of solvents being present in an amount of at least about 22 percent and at most about 50 percent, calculated on the weight of the acetylene solution, and the solution being maintained above the solidification point.

4. The process of storing and handling acetylene solutions with a high concentration of at least 50% acetylene at low temperature at substantially normal pressure for prolonged periods of time without danger of explosion which comprises dissolving, storing and handling acetylene at temperatures below about 80 C. in a mixture of solvents for acetylene, which consists of about 70 to about 99.0 percent of acetaldehyde, about 0.4 to about 8 percent of acetone, about 0.5 to about 20 percent of methyl ethyl ketone and about 0.1 to about 8 percent of methyl isobutyl ketone, the total amount of methyl ethyl ketone and methyl isobutyl ketone being not higher than about 25 percent, said mixture of solvents being present in an amount of at least about 22 percent and at most about 50 percent, calculated on the weight of the acetylene solution, and the solution being maintained above the solidification point.

5. The process of storing and handling acetylene solutions with a high concentration of at least 50% acetylene at low temperature at substantially normal pres sure for prolonged periods of time without danger of explosion which comprises dissolving, storing and handling acetylene at temperatures below about 80 C. in a mixture of solvents for acetylene, which consists of about to about 90 percent of acetaldehyde between about 0.1 and about 15 percent of acetone and between about 0.5 and about 25 percent of a compound selected from the group consisting of methyl ethyl ketone and methyl isobutyl ketone and mixtures thereof, the total amount of acetone, methyl ethyl ketone, and methyl isobutyl ketone being between about 10 and about 30 percent, said mixture of solvents being present in an amount of at least about 22 percent and at most about 50 percent calculated on the weight of the acetylene solution, and the solution being maintained above the solidification point.

6 The process of storing and handling acetylene solutions with a high concentration of at least 50% acetylene at low temperature at substantially normal pressure for prolonged periods of time without danger of explosion which comprises dissolving, storing and handling acetylene at temperatures below about C. in a mixture of solvents for acetylene, which consists of about 70 to about 99.4 percent of acetaldehyde, about 0.5 to about 25 percent of a ketone selected from the group consisting of methyl ethyl ketone and methyl isobutyl ketone and mixtures thereof and of about 0.1 to about 15 percent of acetone, said mixture of solvents being present in an amount of between about 25 and 50 percent calculated on the weight of the acetylene solution, and the solution being maintained above the solidification point.

7. The process of storing and handling acetylene solutions with a high concentration of at least 50% acetylene at low temperature at substantially normal pressure for prolonged periods of time without danger of explosion which comprises dissolving, storing and handling acetylene at temperatures below about 80 C. and under substantially atmospheric pressure in a mixture of solvents for acetylene, which consists of about 70 to about 99.4 percent of acetaldehyde, about 0.5 to about 25 percent of a ketone selected from the group consisting of methyl ethyl ketone and methyl isobutyl ketone and mixtures thereof and of about 0.1 to about 15 percent of acetone, said mixture of solvents being present in an amount of between about 25 and 50 percent, calculated on the weight of the acetylene solution, and the solution being maintained above the solidification point.

References Cited in the file of this patent UNITED STATES PATENTS UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 2 ,925 384 February 16 1960 Karl Winnacker et al.

It is hereby certified that error appears in the-printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 4 in the table column 1 thereof line 3 of Example (4), for "79.9" read 79.0

Signed and sealed this 30th day of August 1960.

( SEAL) Attest:

ERNEST W. SWIDER ROBERT C. WATSON Attesting Oflicer Commissioner of Patents

Claims (1)

1. THE PROCESS OF STORING AND HANDLING ACETYLENE SOLUTIONS WITH A HIGH CONCENTRATION OF AT LEAST 50% ACETYLENE AT LOW TEMPERATURE AT SUBSTANTIALLY NORMAL PRESSURE FOR PROLONGED PERIODS OF TIME WITHOUT DANGER OF EXPLOSION WHICH COMPRISES DISSOLVING STORING AND HANDLING ACETYLENE AT TEMPERATURES BELOW ABOUT -80*C. IN A MIXTURE OF SOLVENTS FOR ACETYLENE, WHICH CONSISTS OF ABOUT 70 TO ABOUT 99.4 PERCENT OF ACETALDEHYDE, ABOUT 0.5 TO ABOUT 25 PERCENT OF A KETONE SELECTED FROM THE GROUP CONSISTING OF METHYL ETHYL KETONE AND METHYL ISOBUTYL KETONE AND MIXTURES THEREOF AND OF ABOUT 0.1 TO ABOUT 15 PERCENT OF ACETONE, SAID MIXTURE OF SOLVENTS BEING PRESENT IN AN AMOUNT OF BETWEEN ABOUT 22 AND 50 PERCENT CALCULATED ON THE WEIGHT OF THE ACETYLENE SOLUTION, AND THE SOLUTION BEING MAINTAINED ABOVE THE SOLIDIFICATION POINT.