?atenied Jan. 23, 1934 _ UNITED ‘STATESDPATENT OFFICE . 1,944,17 5 , PROCESS OF ODORIZING LIQUEFIED PETROLEUM GASES ~ Frederick E. Frey, Bartlesville, 0kla., assignor to Phillips Petroleum Company, Bartlesville, 0kla., a corporation of Delaware No Drawing. Application October ‘I, 1929 Serial No. 398,109 3 Claims. (Cl. 4H) This invention pertains to the odorizing 01' equal volatility to the lique?ed gas. For example, liquefied petroleum gas. ' it a soluble compound boiling at a temperature It is well known that lique?ed petroleum gas somewhat higher than propane, such as di such as butane and propane, when mixed with methylsul?de be used as an odorizer, the con 5 air, formv explosive mixtures._ As the odor of centration delivered will be less than the con- 60 such petroleum gases is too weak to warn those centration in the liquid fuel at all times. Con present where such gases are escaping, the use sequently, the emptying of a cylinder by evapo of lique?ed petroleum gas, as a fuel, especially ration, will cause a continuous increase in the is attended by some danger of ?re and explo- concentration of the odorizer in the liquid, and lo sion from leaks and open jets. in the gas delivered. However, I recommend 65 I have discovered that an adequate odor may that a soluble liquid of comparatively low vapor be imparted to such gases by adding to the pressure, such as kerosene be present in the cyl same while stored in liquid condition, in a cyl- inder containing the mixture of propane and inder or the like, an odorous material in su?l- dimethylsul?de, to limit the increase in concen u cient amount to odorize a mixture 0! the gas tration that can take place when the cylinder is 70 with the maximum amount of air that will per- nearly empty, and thus prevent the discharge of " mit combustion. This may be accomplishedby excessive amounts of odorous material. introducing vinto the cylinder containing the If a compound or limited solubility is used as lique?ed gas, an odorous material of su?lcient an odorizer, I have found that some of the more so volatility to deliver the necessary concentration promising materials will evaporate too readily, 75 to the gas, under the high pressure developed and the concentration delivered decreased as the in the cylinder. However, very few substances propaneiuel is evaporated. I therefore propose, may be employed for- this purpose, due to the as a further example, to use with the fuel, a fact that the gas when utilized, changes from liquid of- low volatility and limited miscibility, 25 liquid to ‘gaseous condition, and consequently, ,to dissolve a part of the odorous material to form so the proportion of the odorous substance may ' a separate liquid phase which will deliver a su?l vary in the gaseous ?uid as the content of the cient concentration or the odorous material at cylinder diminishes, as the lique?ed gas is used all stages 01' emptying by evaporation. For this from the same. purpose,v glycol can be used in a cylinder of 30 In the case oi’ a gas consisting mainly of prc- propane iuei‘odorized by ammonia. s5 , pane, I have found it advisable to use an odorous It has heretofore been proposed to add odor material of high volatility, but the number of izing agents to a gas stream, but so far as I am substances possessing both 'the required odor aware, no proposal has been made prior to my strength and volatility is limited. Consequently, invention to incorporate an odorizing agent di 35 special measures must be used to make materials rectly into gas while the latter is in liquid con- 90 of other than the correct volatility serve the dition and held under pressure in a cylinder or purpose. the like. The latter procedure presents prob Furthermore, it is desirable that the concen- lems which are not present in the odorizing of tration of .odor delivered be fairly constant, a gas stream. For instance, it is necessary to 60 whether the cylinder is lull of liquid fuel or avoid the delivery or excessive concentration of 95 nearly empty. ' a miscible odorizer from a near-empty cylinder, , In accordance with my invention, I have dis- and it is necessary to control the concentration covered that ii propylene is used as an odorizer throughout delivery of a charge, when an odor of propane for example, since it is highly miscible izer of limited miscibility is used in connection 45 with propane and equally volatile, it will be‘ with lique?ed gas in a cylinder.‘ _100 delivered in fairly constant concentration as the . One prior inventor uses thio-acetone in a gas . 4 contentoi the cylinder‘diminishes. stream for odorizing purposes. He did not con Therei'ore, as a part of the present invention, ‘template the use oi organic sul?des in general, I proposes. lique?ed iuel consisting essentially and dealt only with the odorizing of poisonous w 59 of propane and propylene, in which the pr'opy- iuel gases, while I deal with non-poisonous gases \05 lene is present in suincient quantity to impart an which are stored in liquefied condition, and wish odor to all?ammable mixtures with air. to introduce into the lique?ed gas, only an I have also discovered that in odorizing lique- amount of odorizer su?icient to odorize an ex ?ed pretroleum or the like, it is not absolutely plosive mixture (about 2.0% in air). A poison 55 necessary to use an'odorizing substance having ous mixture 01 water or producer gas’ (0.05 to 110 o 2 asaaivs 0.10% in air) would require a much higher odor odorize, and this I accomplish by the invention concentration. as explained above. From the foregoing it will be understood that I am aware that substances other than those my invention involves the following: - speci?cally mentioned are suitable for my pur First.—The odorizing of lique?ed petroleum poses, and that changes may be made in the gases to warn vthose present when there is a foregoing proposals, without departing iron the su?lcientamount of such gas escaping to form spirit of -the invention, as expressed in the an explosive mixture with air. 7 claims. Second.—.-To'impart the odorizing agent to the What I claim and desire to secure by Letters gas whi . he latter is in lique?ed condition and Patent is: ‘ held'underpressure in a cylinder or the like.v ' 1. A lique?ed petroleum gas having admixed Third-To employ only such agents as will therewith a volatile odorizing agent in amount furnish an odor of the necessary strength during su?icient to odorize the leanest ?ammable mix the entire delivery of the gas from the cylinder. ture of said gas with air, and containing a sub 15 Fourth.-—Avoiding the delivery of excessive stance having the characteristics of kerosene to concentration of a miscible odorizer from a avoid the delivery of excessive concentration of near-empty cylinder by the introduction of a said odorizer from a substantially empty cylin suitable retaining agent such‘ as kerosene or der from which the gas is delivered. v glycol. ‘ 2. Lique?ed petroleum gas stored under pres 20 Fifth-To provide a novel liquefied gas mix sure and having admixed therewith a.miscible ture. 1 odorizing agent, and a substance having the It is believed that the invention may be readily characteristics of kerosene to prevent the de understood from the foregoing description, but livery of excessive concentration of the odorizing by way of reiteration it may be explained that at agent from a substantially empty chamber from 25 the present time, large amounts of propane and which the gas is delivered. the like are obtained from the treatment of 3. Lique?ed petroleum gas containing a‘ vola natural gas, oil ,gas and the like. Such propane tile odorizing agent and'asubstance dissolving or its equivalent is placed under pressure and the odorizing agent, but miscible to no more stored in gas-tight pressure cylinders, from than a limited degree with the lique?ed petro ‘so which the gas ‘evaporates and is utilized by the leum gas. ' ' ' consumer in gaseous condition. It is such lique FREDERICK E. F'REY. ?ed petroleum gases as this which I propose to 35 45 50 55 60 65 14 70 14 .