US2067056A - Oil still - Google Patents

Description

Jan. 5, 1937. J. H. LAWRENCE 2,067,056

` OIL STILL Y Filed sept. 27, 1930 2 sheets-sheet 1 www@ fg? .f v

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ATTORNEYS J. H. LAWRENCE OIL STILL Filed Sept. 27, 1930 Janls, 193.7.

2 sheets-sheet 2 ATTORNEYS Patented Jan. 5, 1937 y orifice OIL STILL John H. Lawrence, New York, N. Y., assgnor to Metropolitan Engineering Company, Brooklyn, N. Y., a corporation of New York Application september 27, 1930, serial No. 484,776

1 Claim.

My invention relates to oil stills of the pipe or tube and drum type for the cracking of petroleum hydro-carbon and for theY distilling generally of petroleum and similar products'.

In stills of the above type the oil is heated while passing through a tube or pipe in a furnace and is then passed into a separating or digesting chamber to which little or no additional heat is added. The hydro-carbons to which the heat is imparted are decomposed at high temperatures to a greater or less extent depending on the constitution of the oil, time of .heating and other factors and in this decomposition the carbon is set free in quantities depending on the composition of the oil and the extent of cracking. This carbon may act as an insulating material if it should settle on the inner vwall of the heating tubes and would thus cause over-heating and destruction or rupture of the tube.

Heretofore the heatingtubes have not been subjected to any substantial extent to direct contact with, or to the direct radiation of heat from, the furnace but have been heated by Contact with the products of the completed combustion and, therefore,gby conduction rather than by radiation.

`Objects of my invention are to provide Va method of heating oil, ina still, in which the oil is subjected to direct radiation from the burning fuel in the combustion zone; in which the transfer of heat into oil or hydro-carbons is at the highest rate; and in which this heating is accomplished Without danger of destruction of the heating tube.

With these and other objects in View, which will more fully appear from the following description, my invention comprises the method and apparatus described in the following specification.

Various features o-f the invention are illustrated in the accompanying drawings in whicht Fig. l is a perspective View, with portions broken away, of the heating pipes or coils and combustion chamber of an oil still embodying a preferred form of the invention;

Fig. 2 is a cross-sectional elevation of the furnace and heating tubes shown in Fig. l;

Fig. 3 is a perspective View of a furnace and heating coil similar to that of Fig. l embodying a modified form of the invention;

Fig. 4. is a cross-sectional elevation of the fur` nace and heating tubes of Fig. 3, and

Figs. 5 and 6 are, respectively, a longitudinal view and a cross-sectional View of a length of individual tubing or pipe forming an element of the preferred embodiment of the invention.

In my invention the fuel is burnt in the combustion Zone and is then drawn through an outlet and then to theexhaust flue or stack. The fuel may be of any suitable or available type, preferably a` fluid fuel such as oil, gas or powdered coal. The oil to be heated is rst passed into' the heating coils in the preheating or outlet flue Vof the furnace. In these coils in which the oil'is subjected to heating by conduction of the heat from the hot combustion gases, the oil is passed in parallel paths through parallel coils to provide a` moderate velocity through the ,coils and to give the oil sufficient time to abstract the maximum amount of heat from the hot `combustion gases. This parallel arrangement of the coils also enables the oil to pass through the preheating coils with a. minimum drop in pressure and to thus preserve the pressure.

The oil streams are then reunited and passed in a single continuous stream through lengths of pipe connected in series to form alcontinuous coil. Thelengths of pipe of this coil line the combustion chamber, or the walls of the combustion chamber, and are subjected to direct radia tion from the burning gases at a maximum intensity.

To increase to the greatest extent possible the absorption of heat, the tubes exposed to direct radiation are provided with ns extending between adjacent tubes to receive the heat reaching the spaces between the tubes and conduct this heat into the interior of the tube. The oil then passes from the coil into a receiving drum, digesting chamber or other distilling apparatus.

During the passage of the oil through the preheating coils in which it is heated by conduction of heat from the products of the completed combustion, the velocity of the oil and consequently the drop in pressure are relatively low. The oil then enters a continuous coil, the pipes of which are subjected to direct radiation, at a pressure suiicient to provide the maximum velocity of oil through the pipes heated by radiation and to thus sweep out of this coil the carbon that may wif,

be formed by a partial or initial cracking of the hydro-carbon.

Referring more particularly tol Figs. 1 and 2 of the accompanying drawings, oil is supplied to an inlet header I!) from which it passes in parallel into a number of heating pipes I I, four such pipes being shown by way of example. These pipes extend transversely through the outlet ilue I2 of the furnace and are united at alternately opposite projecting ends to adjacent parallel heating tubes by means of the return bends I3 and I4. Any suitable type of return bend may be employed, right-angled ones with end plugs being preferred as they permit a ready access to the tubes for cleaning.

The pipes II nearest the inlet ends of the ilue I2 deliver into the header I 5. From the header I5 the oil enters one of a number of pipe or tube lengths I6 that are arranged about the inner surface of the combustion chamber I'I. The tubes I6 project through end walls of the combustion chamber I'I and are connected in series by return bends I8 and I9 at the projecting ends. The return bends I8 and I 9 may be similar in form and construction to the return bends I3 and I 4. A drain 20 may be arranged at the lowermost of the return bends I8 and I9. The oil thus passes in a continuous stream through the pipe lengths I6 at a velocity much greater than that of its passage through the preheating coils II. In the example shown in Figs. 1 and 2, the velocity through the pipes I 6 would be four times that through the preheating pipes II. From the last of the pipes I6 the oil passes through the outlet pipe 2| toy the receiving or separating drum or digesting chamber not shown.

Fuel for combustion in the combustion chamber I I is supplied through a pair of iluid fuel burners 22 and 23 positioned at opposite ends of the furnace. These burners may be of any suitable type, oil burners being shown by way of example. The air and fuel supplied through these burners is burned in the combustion chamber I1 and the products of combustion after having given up heat by radiation to the pipes I6 pass through the outlet ue I2 and impart heat to the heating pipes I I. They are then withdrawn through an outlet ilue 24 and thence through a pair of outlet ducts 25 and 26 to inlets arranged at opposite ends of a fan 21. The fan 21 is driven by a motor 28 and delivers the exhausted products of combustion to a ue or stack 29.

To increase to the maximum extent the radiation receiving capacity of the tubes I6, they are provided with flanges or iins 30 arranged to extend longitudinally from the outer surface of the tubes at positions on diametrically opposite sides thereof as shown in detail in Figs. 5 and 6. These ns are not made continuous with the length of the pipe or tube but are made in short areas in order to prevent distortion. The ns are arranged between successive pipes as shown in Fig. 2 occupying the spaces between adjacent pipe lengths, and thereby intercepting heat rays directed between the pipe lengths and receiving the heat of such radiation and conducting it to the pipe.

A suitable insulating material SI encloses the outer surface of the heating tubes I6 and the outermost tube I I and prevents loss of heat therefrom. In the modification shown in Figs. 3 and 4 the arrangement of the tubes or pipes II and I6 and of the combustion chamber Il and outlet flue is similar to that of Figs. 1 and 2, but the combustion chamber I'I is cylindrical, or circular in cross-section, so that each of the tubes or pipes I6 is equidistant from the center of the combustion chamber and thus receives an equal amount of radiated heat.

What I claim is An oil still comprising a combustion chamber having a wall formed of parallel bare horizontal heat absorbing tubes projecting at their opposite ends beyond said combustion chamber, said tubes having bare fins spanning the space between adjacent tubes to form a substantially continuous furnace wall exposed directly to the heat in said furnace, and burners at opposite ends of said combustion chamber to burn fuel in direct heat transferring relation to said bare tubes, and an olf-take for products of combustion midway of said last named ends.

JOHN H. LAWRENCE.

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