US1708076A - Process for heating oils - Google Patents

Description

AFTER 9, 1929. J. c. BLACK fi,78,@76

PROCESS FOR HEATING OILS Filed May 9, 1924 Patented Apr. 9, 11929.

UNITED STT matte arr aria.

J OHN C. BLACK, 0]! DESTREHAN, LOUISIANA, ASSIGNOR, BY MESNE ASSIGNMENTS, TO GASOLINE PRODUCTS COMPANY, INC., OF WILMINGTON, DELAWARE, A COR/PO TION OF DELAWARE.

Application filed May 9, 1924. {Serial No; 712,156.

This invention relates to a process for heating petroleum oils preparatory to d1st1lla tion or for cracking purposes or for heating oil for any purpose.

The heater is of tubular construction and the elements may be of series or multiple connection and may be connected to a still or evaporator or in some types of cracking apparatus may be connected to reaction chambers, carbon catchers or evaporator-s or may be connected to coolers or heat inter-changers, the

' counter current relation to each other; that is to say the colder material to be heated is first passed in contact with the outgoing heating medium and asthe colder material 1s gradually heated, it comes in cont-act with increasingly hotte'r heating medlum until finally the outgoing heated material meets the incoming heating medium when the latter. is at its highest temperature. In this Way, the greatest amount of heat may be'absorbed and the efliciency of interchange 1s a maximum.

Tubular oil heaters are usually constructed on the above principlethe elements being so arranged that the oil passing through the final tubes will be subjected to the hottest gases in the furnace-and the entering colder oil will be subjected to the reduced temperature of the exit gases, thereby apparently obtaining the best results and the inost etiiclent operation. 4 t

I have found, however, by practlcal experience that a heating element placed 1n a furnace constructed on the above principle will have a short life, the tubes carrying the hottest oil in the hottest portion of the furnace ,will sag and burn out and will require con tinual renewal of tubes. v

The reason for this is that the oil entering the final heating elements will have attained very closely its maximum temperature with the result that there is a reduced heat differential between the oil and the heating me- PROCESS FOR HEATING OILS.

dium so that the oil absorbs or carries away only a small amount of heat which permits the pipes or tubes to become highly overheated causing their eventual destruction.

Now I have found that I can overcome this difficulty in a very simpleand efficient man ner by placing the initial heating elements (carrying the colder oil) in the hottest por-- tion of the furnace where it is subjected to the highest temperature of the heatin medium. In this way, the heat difi'erentia is at a maximum and a large amount of heat is absorbed by the oil which will maintain the tubes in a comparatively cool condition, thereby prolonging their life and largely prevent the sagging of the pipes and will effectually prevent their destruction by burning out. The position of the initial coil or element in the furnace is such that it'acts as a protector between the extreme heat of the fire or heating medium and the final coil or heatmg element by interposing a cooling device to the fire or heating medium and functions as such to the extent that the final coils or heating elements will be undamaged by excessive heat.

The arrangement of the. ooiis or heating elements are such that tlieoil passes first through the initial heating element where it is subjected to the highest temperature of theheating medium; it then passes to the elements in contact with the exit or final heating medium; it then flows in a countercurrent manner in relation to the heating medium, and eventually emerges at a point Where the heating'medium is leaving the initial coils or heating elements. In this way, the latter part of the heating operation is done on a countercurrent principle, the initial coil or element acting as a preliminary or auxiliary coil to the balance of the heating element.

By reference to the drawing and the following description of its operation, the invent-ion may bereadily understood.

The drawing shows a diagrammatic elevation of a heating element placed in a furnace and clearly shows the method of construction. I only show a single series of tubes or pipes but these could be multiplied and connected in multiple or series which would be readily understood by anyone familiar with the art to which this invention pertains.

The drawing represents a brick furnace setting-1; 2 is the firebox orcombus'tion chamber; 3 is the exit gas space and 4 is the stack; 5 is a burner for supplying heat to the apparatus; 6 is a pump for circulating the oil through the coils or heating elements; 7 is a tank to hold the oil to be heated; the flow of oil from the tank 7 to the pump 6 is through the pipe 8 and valve 8 the pump 6 discharges through line 9 to the initial heating coil or element 10, from which it flows through line 11 to the entrance end of the coil or heating element 12 from which it flows toward the hotter portion of the furnace and exits at a point substantially where the heating medium leaves the coil 10; the exit end of the final coil or heating element 12 is shown as 13 and may be connected to any auxiliary apparatus desired, such as a still, evaporator, fractionating tower or, if used for cracking purposes, may be connected to a still, a reaction chamber or carbon catcher, or it may be connected to a heat exchanger or cooler for some classes of refining operations.

The operation of the apparatus is as fhllows:

Ihe pump 6 is started, drawing its supply of oil to be heated through the line 8 and valve 8' connected to the oil supply tank 7 the pump discharges the oil through the 'line' 9 into the heating element 10, which I have designated as the initial or primary heating element; this element is connected in series relation with the final or secondary heating elementor coil 12, the ,two being connected by pipe 11; coil 12 has anoutlet 13 connected to any subsequent or auxiliary apparatus desired which is immaterial to the operation of the heater; the fires are now started from burner the hot combustion gases in the combustlon space 2 will ascend through the coils or heating elements, passing first through the initial or primer coils or ele-. ment wherein the coolest oil "partially cooled combustion gases ascend ows; then the through the final or secondarycoils or element wherein the oil flows in a counter current direction to the ascending gases and is pro ressively heated as it descends through 1 the eating element and comes in contact with the increasing temperature of the combustion gases; the 011 then passes out of the final or secondary coil or element through pipe 13 for further manipulation or treatment.

By this arran ement of heating coils or elements, I am enabled to prolong the life of the coils and to increase the capaclty of the appathe fire and partially cools the ascending combustion gases as they flow through the coil, so that the gases impinging on the lower portions of the coil 12 are considerably reduced in temperature and will not injure the metal by burning as would be the case if the bottom coils carried the hottest oil, for the reason that their heat absorbing capacity is much reduced as the oil is practically up to its desired final temperature in the terminal passes of the coil.

It is to be understood that this arrangement of coils and furnace could be reversed, the combustion gases entering the coil space at the top and leaving at the bottom, the coil arrangement would then be reverscdthe initial or primary coil or element being at the top and the secondary 'coil or final heating ratus; the coil 10 absorbs the radiant heat of i element would be below with its outlet below the initial coil or element.

As an economy, a heat interchanger could be interposed in the pipe 9, either as" a preheater in the furnace space 3 or as a vapor or liquid heat interchanger.

I have not 1 shown this on the drawing as it complicates I 1. A process of heating petroleum oils in I:

tubular coils situated in a furnace which comprises first passing the oil through the part of the coil located in the hot-test zone of the furnace, concurrent with the passage of combustion gases 1n sald furnace, then passing the oil directly through a portion of the coil situated in the coolest zone of the furnace, and removing the oil from the coil at a point located at the point intermediate the hottest and coolest point of the furnace.

2. A process for continuously heating petroleum oil which comprises first passing the oil through a coil at the point of maximum heatlof the furnace, passing the oil concurrentl with the flow of combustion gases in the urnace, then passing the oil through a portion of the coil situated in a relatively cooler zone of the furnace, passing the oil counter-current to the flow of combustion gases and removing the oil from the coil at a point intermediate the hottest and coolest zone 'of'tlie furnace.

In testimony whereof I hereunto affix my

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