US1965105A - Refining hydrocarbons - Google Patents

Description

y 3, 1934. M. R. MANDELBAUM 1,965,105

REFINING HYDROCARBONS Original Filed: Sept. 19 1930 INVENTOR 4:? W

BY MGM ATTORN EY Patented July 3, 1934 UNITED STATES PATENT OFFICE Was-m REFINING HYDROCARBONS Application September 19, 1930, Serial No. 482,966 Renewed August 8, 1933 Claims.

This invention relates to refining hydrocarbons and more especially to the refining of gasoline produced from heavier oils by cracking.

Cracked gasoline contains unstable, unsatu- 5 rated compounds which unless removed render it unsuitable as motor fuel, for such compounds tend to discolor on exposure to light and to form deposits. It is, therefore, necessary to refine cracked gasoline by removing such compounds.

One method of refining cracked gasoline consists in contacting the cracked gasoline in vapor phase with solid adsorbent treating material capable of polymerizing the compounds above referred to. This treatment usually is suflicient to economically produce refined stabilized gasoline, but in the case of especially recalcitrant products, refined stabilized gasoline can be obtained only by use of an increased ratio of treating material to gasoline treated, thereby increasing the refining 20 cost to such anextent that the process becomes uneconomical.

An object of this invention is an improved method of refining and stabilizing gasoline where in the gasoline is refined, but not stabilized, by vapor phase contact with solid adsorptive material and is subsequently stabilized by contact in liquid phase and in substantially the same ratio with additional solid adsorptive material, while maintaining the activity thereof for vapor phase 30 refining.

According to one embodiment of my invention, refined stabilized gasoline may be economically obtained from recalcitrant cracked gasoline. When the ordinary ratio of solid adsorptive treating material to gasoline treated is used with recalcitrant gasoline, the vapor phase contact step yields a refined butunstabilized product. The refined gasoline is then condensed and cooled well below its condensing temperature, after which it 40 is passed through a second body of the same adsorptive material as used in the vapor phase step and in substantially the same ratio of treating material to gasoline. Passage of the refined gasoline through this second body of treating material stabilizes the gasoline and the activity of the treating material for vapor phase refining is unimpaired due to the low temperature of the liquid gasoline. After the normal period of operation, the treating material used in the vapor phase step becomes spent and I use the treating material of the liquid phase step to replace the spent .treating material of the vapor phase step. In this way, I am able to maintain the same ratio of gasoline to treating material that would be required to produce a refined but unstabilized prodnot by vapor phase treatment alone. Preferably, I utilize two towers so connected that either can be used for the vapor phase step or the liquid phase step, and provide means for reversing the order of fiow through the tower. With this arrangement, it is necessary only to change the charge of one tower at a time.

An additional advantage of my invention is that it supplies for the vapor phase treating step a treating material, which, by having treated a quantity of hydrocarbon liquid, becomes seasoned and does not have the objectionable properties of fresh solid adsorbents. It is well-known that such materials, when fresh, are too active and cause an increase in the boiling range of the hydrocarbons being treated. I have found that by passing large amounts of liquid hydrocarbons through such materials before they are used for vapor phase refining, they retain their desired efiiciency, but without the hyperactivity which raises the boiling range of the oil.

Other objects, novel features and advantages of the invention will be apparent from the following specification and accompanying drawing, wherein is disclosed diagrammatically one form of apparatus for refining cracked hydrocarbons in accordance with my invention.

Cracked hydrocarbon vapors are supplied from a cracking unit or re-run still through a pipe 10 to a bubble tower or other fractionator 11. The hydrocarbon fraction to be refined, usually gasoline, is discharged from the fractionator 11 through the pipe 12 which terminates in branch pipes 13 and 14 leading to treating towers 15 and 16 respectively, the pipes 13 and 14 being controlled by valves 17 and 18. The treat ng towers 15 and 16 are provided with funnel-shaped fluid permeable shelves 19 and 20 terminating in discharge spouts 21 and 22 controlled by valves 23 and 24. From the lower portions of the towers 15 and 16, pipes 25 and 26 lead to separators 27 and 28 from which pipes 29 and 30 controlled by valves 31 and 32 lead to a condenser 33. A pipe 34 leadsto a gas separator 35 andpipes 36 and 37 controlled by valves 38 and 39 lead from the separator to the pipes 30 and 29 respectively. Pipes 40 and 41 controlled by valves 42 and 43 lead from the pipes 14 and 13 respectively and connect with a discharge pipe 44.

The treating towers 15 and 16 are provided with drainage pipes 45, 46 controlled by valves 47 and 48, the pipes leading to tanks 49 and 50. The separators 2'7 and 28 are provided with drainage pipes 51 and 52 controlled by valves 53 and 54, these pipes also leading to the tanks 49 and 50.

Pipes 55 and 56 lead from the tanks 49 and 50 to the inlet of a pump 57, the outlet of which is connected to a pipe 58 leading into the upper part of the fractionator 11.

When this apparatus is operated to refine gasoline in accordance with my invention, the towers 15 and 16 are charged with solid adsorptive treating material capable of polymerizing undesirable, unstable, unsaturated compounds contained in cracked gasoline. This treating material may be fullers earth, or any other solid adsorptive material which has the required properties.

The various valves are so set that the vapor preferably is delivered to the upper portion of one of the treating towers and is withdrawn from the lower portion of such tower after it is passed through the treating material contained therein. The ratio of gasoline treated to the treating material is such that the gasoline is refined, but not stabilized, this being accomplished with a lower ratio than would be required both to refine and stabilize the gasoline. The refined vapors are then passed through a separator in which entrained liquids are removed from the vapors and the latter are then conducted to the condenser 33 where they are liquefied and cooled materially below their condensation temperature. The liquefied gasoline is then led to the gas separator 35 by which gas in the liquid is removed and the liquid gasoline is then preferably introduced into the bottom of the other treating tower and caused to flow through the body of treating material contained therein. By this treatment, the gasoline is stabilized and later discharged through the pipe 44 and conducted to a storage tank (not shown). After the treating material in the vapor phase state has become spent, it is withdrawn from this tower and a fresh charge introduced. The valves are then so manipulated that the vapor phase step is now carried on in the tower in which formerly the liquid phase step was carried on and the liquid phase step is carried on in the tower having the fresh treating material.

Assume that the vapor phase step is to be carried on in the tower 15 and the liquid phase step in the treating tower 16. I In this arrangement, the following valves would be open; 17, 31, 38 and 42, while the following valves will be closed; 18, 32, 39 and 43. Upon re-charging of the tower 15 after the treating material therein has become spent, the valves which formerly were closed will be open and the valves which formerly were opened will be closed.

Condensate and polymers collecting in the treating towers and separators are drained into the tanks 49 and 50 from which they are pumped back into the fractionator. When the vapor phase step is carried on in the tower 15, valves 47 and 53 will be open while valves 48 and 54 will be closed and when the vapor phase step is carried on in the tower 16, valves 48 and 54 will be open and valves 47 and 53 will be closed.

The vapor phase step may be carried on at any desired pressure up to the pressure of the cracking or other distillation unit to which the tower 11 is connected. The pressure of the vapor phase step may be regulated by means of the valve 35b of the vent 35a for the gas separator 35. Where this pressure is of the order of 50 or 60 pounds and where gasoline is being treated, the temperature of the vapors in the treating tower will be between 300 and 350 F. The refined liquefied gasoline should be at a temperature below 150 F. when contacted with the treating material in order to minimize any reaction tending to impair the activity of the treating material for vapor phase use.

It is of course understood that the apparatus above described may be varied without departing from the spirit of the invention as defined in the appended claims and that the method may be carried out with any suitable apparatus.

I claim:

1. In a two stage treating process for refining and stabilizing cracked gasoline characterized by vapor phase contact of the cracked gasoline with a charge of solid adsorptive material, condensation of the refined vapors and subsequent liquid phase contact thereof with additional solid adsorptive material, the steps of using a fresh adsorptive material for the liquid phase contact, thereby seasoning said solid adsorptive material, and then using such seasoned solid adsorptive material for the vapor phase contact.

2. In a two stage process of refining and stabilizing cracked gasoline characterized by passage of cracked gasoline in vapor phase through a bed of solid adsorptive material, condensation of the refined vapors and subsequent passage thereof in liquid phase through a second bed of the same solid adsorptive material, the steps of passing refined condensate through a bed of fresh solid adsorptive material, thereby seasoning the same, and then passing unrefined gasoline vapors through said bed of seasoned solid adsorptive material.

3. In a two stage process of refining and statilizing cracked gasoline characterized by passage of cracked gasoline in vapor phase through a bed of solid adsorptive material, condensation of the refined vapors and subsequent passage thereof in liquid phase through a second bed of the same solid adsorptive material, the steps of passing refined condensate upwardly through a bed of fresh solid adsorptive material, thereby seasoning said material, and then passing unrefined vapors downwardly through said bed of seasoned solid adsorptive material.

4. In a two-stage process of refining and stabilizing cracked gasoline, characterized by passage of cracked gasoline in vapor phase through a bed of solid adsorptive material, condensation of the refined vapors and subsequent passage thereof in liquid phase through a second body of the same solid adsorptive material in substantially the same quantity as in the first bed, the steps of using a fresh charge of adsorptive material for the liquid phase contact, thereby seasoning said material and then using such bed of seasoned solid adsorptive material for the vapor phase contact.

5. In a two-stage process of refining and stabilizing cracked gasoline, characterized by passage of cracked gasoline in vapor phase through a bed of solid adsorptive material, condensation of the refined vapors and subsequent passage thereof in liquid phase through a second body of the same solid adsorptive material in substantially the same quantity as in the first bed, the steps of using a fresh charge of solid adsorptive material for the liquid phase contact and passing refined gasoline upwardly therethrough, thereby seasoning said material and then using such bed of seasoned solid adsorptive material for the vapor phase contact and passing unrefined vapor downwardly therethrough.

MALVIN R. MANDELBAUM.

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