US2111899A - Process for the manufacture of ethylene from oil - Google Patents

Description

1 ethylene is increased to as high as 45% by weight ingested 22, 193s untreu STATES..

l I .moonssron 'nm armena (ICE a Appumnpember 1s, 1935, serial N9. 55,011

' ,-2 emma (cieco-1ro) The subject matter of this invention is a new method for producing ethylene, a hydrocarbon gas (12H4 of the olefin seriesVfrom liquid hydro-v carbon mixtures of the type round in petroleum.'

5 in which new process the correlation of temperatures, reaction velocities and reaction periods of time produce yields of ethylene far in excess of the -yields by the current methodsof, producing ethylene from hydrocarbons.

In the oil industry ethylene is a by-product in converting heavy-oil to gasoline by pyrolysis and 1 the -yieldvof ethylene, depending upon whether the liquid or the vapor phase method of cracking is employed, varies in amounts up to approximately 6% by weight of the charging stock.

In the chemical industry, in the operation di- I rected to the production of ethylene from liquid j .hydrocarbons, a` variation of the vapor phase method used in the oil industry is employed. V

In the oil industry the yieldof liquids is in the order of 75% by weight of the charging stock and the ethylene yield as above indicated is only about 6%; in the chemical industry the yield of liquids is in the order-oi. 40% by weightof the charging stock and the ethylene yield is in the 'order of 10% by weight of 111e chargingstock.

As` distinguished kfrom these prior processes, the present invention provides a method wherein the -yield of lliquids is reduced` to less than 10% by weight of the charging stock and the fyield of of the charging stock.

.One of the `objects ofthis invention is the production of ethylene as'the primary product oi' the operation in converting substantially all of the charging stock to gases, the yield of condensible polymers being inhibited substantially .tol exclusion. This operation is notof necessity .an adjunct to .oil renery operations but can be conveniently located wherever ethylene isfdesired for use either directly orfas a process material.V `Another object of this invention is the production of ethylene from liquid hydrocarbons. wherein I obtain a yield of ethylene as high as 45 by weight of the hydrocarbons charged, my meth# od providingor the ash system cracking of pre,-

heated liquid hydrocarbons, the ethylene thus produced beingl prevented from polymerizing to heavier hydrocarbons'ythereby insuring the maximum yield of ethyleneand the yield of liquids. v

Mynew process produces these novel results from liquid hydrocarbons in a continuous operation, the process comprising the operations ofpre- 4heating `the oil to a suillcientiy high temperature while subjected to suitable pressure and velocity sc that upon dashing the preheated oil into a hotter reaction zone substantially fall of the oil is almost instantly heated and cracked to ethylene and hydrocarbons oi.' lessthanfour carbon atoms, 5 this hot 'gas being immediately shock chilled below the polymerization temperature zone topractically exclude polymerization before a substantial amount of ethylene is polymerized.

In the accompanying drawing I have illustrated 10 diagrammatically embodiments of my invention: Fig. 1 illustrating v an embodiment of the inveng tion wherein lthe reaction zone is externally s' heated; and

Fig. 2 illustrating. an embodiment `oi" the inven- 'lo tion wherein the reaction zone is' internally heated. 1

As an example of the practice of my invention for the production of ethylene from gas oil,` and with reference ilrst of ,all t Fig. 1:l Tlie oil to be 29 processed is taken from any suitable source of supply I and supplied to the pressure preheater 2 at a pressure in the order of, for example, 20

,atmospheres or higher pressure, iiowing continuously through the preheater to the reaction zone 25 3. The oil -is preheated to a temperature in the order of 850 F. In the preheating step of my process temperature and pressure conditionsare i so controlled that the oil remains in the liquid phase. The preheated oil iscontinuously in- 30 iected into the hotter reaction zone 3, flashing into vapor, the temperature of the hotter reactlo'n zone being so controlled that substantially all of' the oil vapor'is converted to ethylene and hydrocarbons of less than four carbon atoms at a tem. 35

perature of inthe order of 1400 F. The' hot gases are immediately shock chilled to below '1000. F. in the cooler- 4 so as to practically exfA clude polymerization before a substantial amount of ethylene; is polymerized, thereby avoiding yields 40 trated in Fg.'2 the procedure is the same as outlined above, the reaction zone being internally heated by hot products of combustion from source 8. Chilling of the hot gasis effected by water 5o injected into the/gas as indicated at 1. The ethylene is separated from the products of py- 'rolysis by chemical reactionas shown at 8.

e example given above I have mentioned 'a tem raturein the order oi' 1400 Il'. with refer' g55l F therefrom vary, but in any case the temperature should not be less thanv approximately 1200? F. and the reaction time should not exceed approximately one and one-half seconds to avoid pro-v ducing condensates. Furthermore, the temper' ature should not exceed 1600 F, because at such temperature ethylene decreases. Preferably the temperature ranges between -1300" F. and A1500 I". and the time varies in inverse relation to the temperature, preferably ranging from approximately one and one-halt seconds to less than one-half secondA in order to obtain the yield 'o1 ethylene.

What I claim is:-

1. The process of producing ethylene from oil,

optimumv which process comprises preheating the oil under superatmospheric pressure while maintaining the oil slightly below its vaporizing temperature at that pressure, injecting al1 of the preheated liquid oil into a owing gaseous medium which contains suiiicient heat for heat exchange to the preheated oil to flash heat the preheated oil to within the temperature range of 1300.F. to 1600 F., at

which temperature all of the hydrocarbons of the carbons as ethylene and hydrocarbons of not more than four carbon atoms.

2. The process of producing ethylene from gas 'oil, which process comprises preheating the oil to a temperature in the order oi' 850 F. while subjected to superatmospheric' pressure, controllingtpressure and time conditions whilelpreheating so that the oil remains in the liquid phase, injecting all' of the preheated oil into a flowing4 gaseous medium which contains sumcientheat for heat exchange to the preheated oil to ilash heat the preheated oil to within the temperature range of 1300 F. to 1600", F., at which temperature all of the hydrocarbons' of the oil are instantly decomposed to ethylene and hydrocarbons .of not more than four carbon atoms, and immediately upon attaining this vtemperature shock cooling to below 1000 F. to exclude polymerizing reactions forming gasoline hydrocarbons and to retain the hydrocarbons as ethylene and hydrocarbons of not more than four carbon atoms. y

THEODORE NAGEL.

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