US2714085A - Thermal conversion of hydrocarbons in the presence of an oxychlorine compound - Google Patents

Description

United vStates PatentO 2,714,085 THERMAL CONVERSION OF HYDROCARBONS IN THE PRESENCE OF AN OXYCHLORINE COM- POUND Carlisle M. Thacker, Wilmington, net, and Hillis 0. Folkins, Crystal Lake, 111., assignors to The Pure Oil Company, Chicago, Ill., a corporation of Ohio No Drawing. Continuation of application Serial No.

34,556, June 22, 1948, which isa continuation of application Serial No. 564,180, November 18, 1944, now Patent No. 2,460,200, dated January 25, 1949. This application June 4, 1952, Serial No. 291,776

4 Claims. (Cl. 196-52) co-pending application Serial Number 564,180, filed November 18, 1944, entitled Thermal Conversion of Hydrocarbons in the Presence of an Oxychlorine Compound, now United States Patent No. 2,460,200, which in turn is a continuation-in-part of our application Serial Number 434,790, filed March 14, 1942, entitled Thermal Conversion of Hydrocarbons promoted by Explosive rganic Nitrogen Compounds, which has since issued as United States Patent 2,435,760.

We have discovered that if hydrocarbons are subjected to suitable time, temperature and pressure conditions to crack the hydrocarbons, in the presence of a small amount of an explosive substance, the cracking reaction is promoted so that higher yields of cracked products can be obtained and cracking can be effected at lower temperatures. Although it is not known why explosive substances promote the cracking reaction, it is thought the shock of or the energy produced in the decomposition of the explosive is communicated to the intimately associated hydrocarbon molecules undergoing decomposition, thus facilitating scission of the carbon to carbon bonds.

One of the objects of the invention is to provide an improved method of converting higher boiling hydrocarbons into lower boiling hydrocarbons.

Another object of the invention is to accelerate the rate of cracking in thermal cracking operations.

Other objects of the invention will become manifest from the following description.

In accordance with the invention, hydrocarbons to be converted are subjected to conversion conditions of time, temperature and pressure in admixture with a small amount of an explosive substance which explodes when heated to or below the temperature of the cracking reaction. The explosive substance is preferably injected directly into the reaction zone in the form of a solution in a solvent; or where hydrocarbon liquid is cracked, in solution or suspension in a portion of the hydrocarbon liquid to be cracked. It is important that the explosive substance shall not be subjected to such temperatures prior to the time it enters the reactor as to cause decomposition thereof. Explosive substances may be injected into the reaction zone in an amount of approximately .05 to 3 mol per cent of the hydrocarbons undergoing cracking, depending upon the particular compound used.

Any known explosive compound whether organic or inorganic which is capable of exploding under reaction conditions may be used. As examples of compounds which are useful, the following are given:

Organic nitro compounds- 2,4,6-trinitroaniline (T. N. A., picramide) 2,4,6-trinitrocresol 2,3,4-trinitrotoluene 2,4,6-trinitrotoluene (T. N. T.)

Trinitrophenylmethylnitramine (tetryl) Picric aci'd 2,3,4,6 tetranitrophenol Nitrocellulose Nitroglycerin Nitromannite Benzazide Chrysammic acid Glycol dinitrate Dinitromethane Benzylazide Lead salt of trinitroresorcinol Ni'trosoguanidine Nitro urea Trinitroethanenitrile Ammonium compounds- Ammonium azide Ammonium bromate Ammonium chlorate Ammonium perchromate Ammonium periodate Picrates of lead, potassium, thallium and zinc Fulminates of silver, mercury and gold Oxalates of and tartrates of mercury and silver Azides of ammonium, lead, mercury, silver, calcium and benzoyl azide Peroxides--Alkyl derivatives of hydrogen peroxide such as ether peroxides, benzoyl peroxide Perbenzoic acid Oxyhalide compounds such as chlorine dioxide, chlorine tetroxide, lead chlorite, and esters of hypochlorous acid such as ethyl hypochlorite Iodine compounds such as iodosobenzcne, iodoxybenzene,

nitrogen triodide Nitrides of mercury and sulfur Amides quinonechlorimide, diazobenzeneimide Compounds which upon decomposition form a halogen or a hydrohalide, particularly bromine, iodine, hydrogen iodide or hydrogen bromide, are particularly effective since these halogens and hydrohalides in themselves are very effective cracking sensitizers. Compounds which decompose to form a free oxygen atom are also highly efiective, since free oxygen in itself has a sensitizing efiect on the cracking reaction. Metal salts, particularly mercury salts, are also good sensitizers since mercury is an active cracking catalyst.

Cracking in the presence of explosive substances may be carried out under sub-atmospheric, atmospheric or super-atmospheric pressures and at temperatures ranging from the lowest temperature at which cracking will occur to a temperature of approximately 2000 F., depending upon the nature of the charging stock and the type of product it is desired to produce. When cracking of hydrocarbon oil is conducted for the purpose of making lower boiling hydrocarbon liquid, such as gasoline, temperatures ranging from approximately 650 to 1200" F. may be used. Where cracking of hydrocarbon oils or gases for the production of aromatic hydrocarbons is prac ticed, temperatures of approximately 1000 to 1500 F. may be used. If it is desired to produce butadiene from hydrocarbon oils, temperatures in the vicinity of l300 to 1600 F. give the best yields and where it is desired to crack hydrocarbon oils to gaseous hydrocarbons, temperatures from approximately 1300 to 2000 F. may be used.

The invention is adapted for use in conjunction with conventional types of purely thermal as well as catalytic cracking operations without the necessity of changing the I operation of said process or the apparatus required except to make provision for charging the explosive substance to the reaction zone.

As an example illustrating how the invention may be practiced, gas oil is charged to a pre-heatin'gcoil in a thermal cracking operation conducted at a maximum temperature of approximately 900 F. and at a pressure of approximately 500 pounds per square inch. In the preheating coil, the gas oil is heated to a temperature of approximately 700" F., and passes into the cracking coil into which a solution of trinitrotoluene in a portion of the gas oil is injected in such amounts that the mol ratio of trinitrotoluene to gas oil undergoing cracking is .001- to 1. The trinitrotoluene solution is injected into the inlet of reaction coil. The yield of gasoline obtained is considerably in excess of that which is obtained in a similar operation Without using any cracking sensitizer.

As another example, a solution of benzoyl peroxide in benzene is injected into a cracking Zone inwhich gas oil is undergoing cracking at a temperature of approximately 850 F. The mol ratio of benzoyl peroxide to gas oil is approximately .01 to l. The yield of gasoline is as good as can be obtained at higher temperatures without Sensitizers.

Although the specific examples are directed to cracking of gas oil, it is to be understood that the invention is applicable to cracking of methane to acetylene, cracking of propane and butanes to ethylene and propylene and crack- 4 ing of hydrocarbon oils in general to lower boiling hydrocarbons. V

It will be seen, therefore, that we have succeeded in improving hydrocarbon cracking processes in that by adding a small amount of explosive to the hydrocarbon undergoing cracking, yields of desirable products can be materially increased for any particular set of reaction conditions or the reaction can be carried out at lower temperatures' and/ or in. less time without suifering any decrease in yield of desirable products.

What is claimed is:

1. The process of cracking higher boiling hydrocarbon oils to lower boiling liquid motor fuel hydrocarbons which consists in subjecting said hydrocarbons to cracking conditions of time, temperature, and pressure in the presence of a small amount of an explosive compound selected from the group consisting of chlorine tetroxide, chlorine dioxide, and lead chlorit'e'.

2. The method in accordance with claim 1 in which the explosive compound is chlorine tetroxide.

3. The process in accordance with claim 1 in which the explosive compound is chlorine dioxide,

4, The process in accordance with claim 1 in which the explosive compound is lead chlorite.

References Cited in the" file of this patent UNITED STATES PATENTS 2,460,200- Thacker et a1; Jan. 25, 1949

Claims (1)

1. THE PROCESS OF CRACKING HIGHER BOILING HYDROCARBON OILS TO LOWER BOILING LIQUID MOTOR FUEL HYDROCARBONS WHICH CONSISTS IN SUBJECTING SAID HYDROCARBONS TO CRACKING CONDITIONS OF TIME, TEMPERATURE, AND PRESSURE IN THE PRESENCE OF A SMALL AMOUNT OF AN EXPLOSIVE COMPOUND SELECTED FROM THE GROUP CONSISTING OF CHLORINE TETROXIDE, CHLORINE DIOXIDE, AND LEAD CHLORITE.