US2246552A - Method for making a fuel consisting predominantly of normally fluid hydrocarbons in solidified form - Google Patents

Description

Patented June 24, 1941 METHOD FOR MAKING A FUEL CONSISTING PREDOMINANTLY OF NORMALLY FLUID HYDROCARBONS IN SOLIDIFIED FORM Eugene D. Stirlen, New Haven, Conn, assignor, by

mesneassignments, to Safety-Fuel Incorporated, West Cheshire, Conn., a corporation of Connecticut No Drawing. Application Deccmbcr 6, 1939,

' Serial No. 307,777

8 Claims.

This invention relates to a fuel consisting predominantly of normally fluid hydrocarbons in solidified form and is a continuation in part of my prior application Serial No. 56,721, filed December 30, 1935, renewed December 1, 1938.

Attempts have been made to produce a satisfactory solidified fuel consisting predominantly of normally fluid hydrocarbons. The solidified fuels heretofore produced have had one or more of the following defects:

(a) Melting during burning with consequent fire danger and improper combustion.

(b) Failure to re-light readily and to burn properly after the fuel has been partly burned and allowed to cool.

(c) Inability to withstand shipment without breaking down the solid condition of the fuel.

Solidified fuels made in accordance with the method hereinafter described are free from any of these defects.

One example of normally fluid hydrocarbons that may be solidified by the application of my method is a petroleum distillate. ample is a mixture of hydrocarbons of the benzene series. Although such normally fluid hydrocarbons as are used for fuel ordinarily contain numerous hydrocarbons, the term hydrocarbons as used in the claims includes the limiting case in which only one hydrocarbon is present. As normally fluid hydrocarbons I may use gasoline although I prefer a petroleum distillate of.closer boiling point. I may also use benzol or a light coal tar distillate consisting predominantly of benzol homologues. The normally fluid hydrocarbons should for ordinary use have a flash point not substantially above normal temperature so that combustion may be started by means of a match or similar lighter while the fuel is at normal temperature.

In carrying out my method I form a solution of the normally fluid hydrocarbons with a soap substantially insoluble or limitably soluble in the normally fluid hydrocarbons and an organic solvent with which said hydrocarbons and soap form a solution. The soap is present in amounts sufficient to jell or congeal the hydrocarbons in the absence or substantial absence of the solvent and the solvent is present in amount sufiicient to bring the hydrocarbons and soap into a unitary liquid solution. An example of sucha soap is the sodium salt of a fatty acid for example stearic acid or the sodium salt of abietic acid, i. e., aodium resinate. An example of such a solvent s 95% ethyl alcohol or 95% methanol or 98% sopropanol. The solvent used must boil pre- Another exdominantly below the boiling point of the major part of the hydrocarbons.

In preparing the unitary solution of hydrocarbons, soap and solvent I may, of course, comingle the hydrocarbons and solvent with the previously prepared soap. In actual practice, however, I prefer to combine the formation of the soap with the carrying out of my method. For this purpose the saponifiable material may be dissolved in the solvent and the hydrocarbon and then saponifled by the addition of alkali; alternatively the saponiflable material may be dis solved in the solvent and then saponified by the addition of alkali and the hydrocarbon thereafter added. The saponiflable material could be dissolved in the hydrocarbon, saponifled by the addition of alkali and thereafter brought into solution by the addition of the solvent but in this case the saponification would be complicated by congelation of the hydrocarbon. As alkali I may use, for example, sodium hydroxide in dry form or in solution and the materials may be heated to assist saponification. Water is only limitably soluble in the solvent-hydrocarbon-soap solution and if an excess of water is introduced in any way as, for example, in solution in the solvent or in the soap, or as a by-product of the saponification reaction, the excess will separate into a second and heavier liquid phase and may therefore be withdrawn and discarded. For this reason the saponifiable material in the hydrocarbonsolvent solution may be neutralized by contacting it with an aqueous sodium hydroxide solution. After saponification has taken place and. the system is permitted to settle, an aqueous solution, containing some rosin soap, will be found in the lower part of the vessel and may be withdrawn. The eificiency by which the water is separated in this manner is enhanced by the presence of a material having a preferential affinity for water such as for example sodium hydroxide which may be present as the result of using an excess of sodium hydroxide over that required for saponification.

In the next step of my process the hydrocarbon-solvent -soap solution, prepared by any of the alternative methods described is subjected to a selective distillation whereby the bulk of the solvent is removed. When substantially all of the solvent has been taken off in this manner the remainder of liquid hydrocarbons and soap will suddenly jell or congeal, thereby producing a solidified fuel consisting predominantly of normally fluid hydrocarbons. The distillation may be carried out with the solution held in the containers in which it is to be shipped, thereby leaving a residue'of solidified fuel in the container and ready for shipment or, if desired. the solidified fuel may be produced in larger masses and thereafter cut into a form suitable for loading into such containers. The solidified fuel may be shipped in the form of slabs or blocks and cut to suitable size as and when required for use.

In normal practice the overhead distillate is condensed and recovered. It consists largely of solvent and alsp contains some water and some of the hydrocarbons. The condensate may separate into a two layer system, the upper layer consisting mainly of hydrocarbons and the lower layer of solvent and water. The condensate is, of course, treated in a suitable manner to recover the hydrocarbons and solvent for reuse.

In one practical embodiment of my invention I dissolved commercial grade E rosin in 95% ethyl alcohol to make a solution having 57.8% rosin by weight. I dissolve sodium hydroxide in water to make an aqueous solution having 40% sodium hydroxide by weight. At room temperature I stirred 44 cc. of the rosin-alcohol solution into 480 ccL-ol' gasoline of a boiling range of 160 F. to about 280 F. I then stirred into the gasolinerosin-alcoliol solution thus made. 19 cc. of the said sodium hydroxide solution and continued stirring at room temperature for five minutes. I then continued stirring while holding the material at 130 F. for several minutes. I have found that this last step of stirring at an elevated temperature is not essential although the eventual character of the solidified fuel produced may be somewhat less firm if it is omitted. After stirring and heating I allow the materials to settie for about 15 minutes whereupon they separated into two layers. I separated the top layer consisting of gasoline, rosin-soap and alcohol. poured it into suitable containers and continued heating until substantially all of the solvent had distilled off and the fuel had congealed at the temperature of distillation to a firm solid condition. The fuel so made burned properly and without any of the defects hereinbefore referred to in a suitable stove leaving a residue amounting to about 6.5% by weight of the original solidified fuel.

The actual soap content of this fuel was found to be about 6.2%. This is determined by evaporating a weighed cake of the solidified fuel to constant weight in an oven at about 100 C.

I carried out another run using the same procedure and the same amount of gasoline but adding 48 cc. of the said rosin-alcohol solution, instead of 44 cc., and 21 cc. of the said sodium hydroxide solution, instead of 19 cc. In this case the solidified fuel produced was more rigid and firm than that produced in the preceding run and burned properly in a suitable stove. It left a residue of about 7.3% of the weight of the original cake of solidified fuel and the actual soap content was about 7%.

If solidified fuel is made in accordance with my invention with a soap content of less than about it does not have sufiicient strength and rigidity to withstand shipment without damage, i. e., without the breaking down of its solid condltion. As the soap content is raised above about 5% the mechanical strength and rigidity of the fuel increases. If the soap content does not ex ceed about 7.5% the fuel on burning leaves a crisp, flaky residue which does not stick to the container in which it is burned and can be easily removed. When the soap content passes above about 9% the length of time required to start the fuel burning properly is seriously increased. When the soap content passes about 11% it becomes difllcult to get the fuel to burn properly and after burning for a short time the flame may go out due to the slagging effect of the soap.

Where ordinary gasoline with a boiling point range from about 130 F. to about 440 F. is solidified according to this invention, and the solidified fuel thereby produced is burned for about 15 minutes in a suitable stove and then extinguished, it is difficult or impossible to get the solidified fuel to again burn properly even though the soap content of the fuel is about 6 or 7%. This dlfllculty is, however, eliminated by using as normally fluid hydrocarbons a petroleum distillate with a boiling range of from about 160 F. to about 280 F. Such a distillate when solidified with a soap content of about 7% and. burned in a suitable stove burns properly throughout its entire burning time. If the flame is extinguished before the fuel has been consumed, and the stove is allowed to cool completely, the fuel can still be easily re-lighted and will continue to burn properly until completely exhausted.

The advantageous properties of fuel made with petroleum distillate of a boiling range of about 160 F. to about 280 F. is also present in a large degree when using a petroleum distillate in which at least of the distillate boils between about F. and about 350 F. These advantageous properties are present in still larger degree and more nearly approaching the properties of the cut from 160 F. to 280 F. when using a petroleum distillate in which at least 90% boils-between about F. and about 300 F.

When a petroleum distillate, rosin-soap and alcohol solution in which the distillate has a boiling range of F. to 280 F., is distilled to bring about formation of the solidified fuel, boiling or distillation starts at about 152 F. and continues until at a temperature of about 158 F. substantially all of the solvent has been distilled off and congelation and solidification of the hydrocarbons occurs. Since the boiling point of the alcohol is about 173 F. and the minimum boiling point of the petroleum distillate about 160 F., it seems evident that the alcohol, water and lower boiling fractions of the petroleum distillate together constitute a ternary boiling mixture containing a relatively greater concentration of water than is present in the petroleum distillate, rosin-soap and alcohol solution. The material distilled off when condensed amounts to about 12% by volume of the petroleum distillate, rosinsoap and alcohol solution subjected to distillation. The condensate produced consists of twolayers, a lower layer amounting to about 13% by volume of the condensate consisting mainly of alcohol and water and an upper layer constituting the remainder of the condensate and consisting mainly of gasoline. Inasmuch as petroleum distillates may contain normal and isomeric homologues of the particular hydrocarbon present, and may in addition contain various hydrocarbons within a particular class and may in addition contain different classes of hydrocarbons, the ternary bolling mixture does not appear to be constant, the hydrocarbon portion thereof being formed by bydrocarbons of successively higher boiling point as the lower hydrocarbons pass 'ofi. Hydrocarbon liquids of other boiling point ranges act similarly when solidified in accordance with this invention.

The fact ,that the fuelsolidifies while hot, insures that neither the" cake of fuel nor the top liquefles while being burned, it becomes very dangerous, since if the container of the burning fuel is knocked over, the liquefied fuel is liable to start a serious fire. Another objection to a solidified fuel which melts, or with which the top surface melts. is that an excess amount of hydrocarbon vapor is given off with consequent interference with uniform and proper burning.

' When the surface or top portion of such a solidified fuel melts and gives off an excess amount of vapor while being burned, the flame mounts higher than proper and changes from a blue flame to an objectionable yellow flame. Solidifled fuel made in accordance with the present invention and employing only rosin soap as the solidifying agent, is non-meltable and entirely safe while burning; not only does it not melt or form any free top layer of melted or liquefied fuel, but it remains completely solid without bubbling or boiling until all the hydrocarbon has burned. This is the case not only when the fuel is burned in a stove, but also when burned in the open and not in a container or stove.

The foregoing specific description is for purposes of illustration and not of limitation and it is therefore my intention that the invention be limited only by' the following claims or their equivalents wherein I-have attempted to claim broadly all patentable novelty.

I claim:

1. Method of making a fuel composition consisting predominantly of normally fluid readily flammable hydrocarbonswhich comprises addin to such hydrocarbons a sodium soap, not more than limitedly soluble in such hydrocarbons and adapted to conceal the same, in amount suflicient to congeal the same, adding thereto an organic solvent for said hydrocarbons and said soap in amount sumcient to bring into solution said hydrocarbons and said soap which solvent boils predominantly below the maHr part of said hydrocarbons, thereafter removing by distillation organic solvent thereby solidifying the residual hydrocarbon soap mixture.

2. Method according to claim 1 in which said soap consists predominantly of sodium resinate.

3. Method according to claim 1 in which said soap consists predominantly of s um stearate.

4. Method according to claim 1 in which the normally'fluid hydrocarbons are a petroleum distillate in which at least of the distillate boils between F. and 3507 F.

5. Method of making a fuel composition consisting predominantly of normally fluid readily flammable hydrocarbons which comprises adding to such hydrocarbons a,sodium soap, not more than limitedly soluble in such hydrocarbons and adapted to congeal the same, in amount sufilcient to congeal the same,'adding thereto an organic solvent for said hydrocarbons and said soap in amount suiflcient to .bring into solution said hydrocarloons and said soap which solvent boils predominantly below the major part of said hydrocarbons, at least some of said materials containing water, permitting the materials to settle, thereby forming an aqueous and an oil phase, separating said aqueous from said oil phase, thereafter removing by distillation from said oil phase organic solvent thereby solidifying the residual hydrocarbon soap mixture.

6. Method according to claim 5 in which said soap consists predominantly of sodium resinate.

7. Method according to claim 5 in which said soap consists predominantly of sodium stearate.

between 130 F. and 350 F.

\ EUGENE 1:. 31mm.