US1862737A - Method of operating furnaces - Google Patents

Description

June 14, 1932. 1 DE FLOREZ 1,862,737

METHOD OF OPERATING FURNACES Original Filed Oct. 29, 1926 3 Sheets-Sheet l Nw I, I HU i mm. ww

June 14, 1932. DE FLQREZ 1,862,737

METHOD 0F OPERATING FURNAGES Original Filed Oct. 29, 1926 3 Sheets-Sheet 2 .lune 14, 1932. L. DE FLoREz METHOD OF OPERATING FURNACES Original Filed Oct. 29, 1926 3 Sheets-Sheet I new and improved type of heater, ma

bustion efficiency.

Patented June 14, 1932 UNITED STATES PATENT OFFICE LUIS DE FLOREZ, 0F POMFRET, CONNECTICUT, .AS-SIGNOR TO m TEXAS COMPANY, .L

CORPORATION OF DELAWARE i METHOD OF OPERATING FURNAOIB riginal application illed ctober 29, 1926, Serial No. 145,054. Divided and this application filed November 3, 1928. Serial No. 317,088.

This invention relates to improvements in heaters for fluids and more particularly to those comprising heating surfaces of the tublar type. My invention, which comprisesba e used for any duties to which this class o apparatus may be put and is particularly adapted for use Where a fluid is to be heated progressively and fuel burned with high com- The invention further relates to a method of effecting a heat treatment of petroleum oils.

This application is a division of my coending application Serial No. 145,054, filed ctober 29, 1926.

The operation of the heater is not limited to the use of an specific type of fuel. In fact one of the o jects of my invention is to provide a combustion chamber which can be readily adapted to burn a wide variety of fuels with relatively little alteration.

My invention is to some extent an elaboration of and an improvement upon the invention shown in m co-pending application, Serial No. 120,06 now U. S. Patent 1,717,- 334, filed July 2, 1926, and the general objects and advantages set forth in said co-pending application are generally applicable to the present invention. However, the structure illustrated and described in this application has many important oints of difference from that disclosed in sai copending application, which oints of difference I shall describe more ully hereafter in the specification. These points of difference result in greatly simplifying, cheapening and improving the construction shown by said copending application, and inproducing a heater peculiarly adapted to exacting conditions of operation.

As important structural features to be covered by this application I may refer to a structure which takes full advantage of the self-supporting arch principle of construction and circular sections whereby a comparatively small amount of steel may be made to perform its structural requirement; the fact that the furnace is adapted to the burning of as, oil or powdered fuel; the method used o supporting the tubular heating surface solely from their upper ends, thus permitting free expansion, ease of removal; simple access for cleaning or replacement' the safety of the apparatus in the event of explosions or bursting of tubes and other important advantages of construction will appear from the drawings and following description.

The general design of the heater is such as to permit the use of both radiant and convection heat in substantially separate stages. Thus I am enabled to apply heat in the convection stage from gases which have been relieved of a considerable quantity of heat thus to avoid overloading these surfaces and eliminate the corresponding detrimental effect. Furthermore rovision is made t0 begin the absorption o the heat generated b the fuel immediately after ignition whic permits the reduction of the combustion space, while the surfaces which are Within vlew of the flame can operate at a. high transfer rate thus reducing the total surface required for a given capacity.

I shall describe an embodiment of my construction as a vertical pipe still adapted to heat petroleum or its products having a vertical cylindrical heating chamber around the inner wall of which the tubes or pipes are disposed, said heating chamber being centrally fired from the top or bottom.

In the preferred construction illustrated I have shown the furnace as fired from the top. The location of the burner or other means b which fuel is introduced into the combustlon chamber is such that the flame tends to remain parallel to the tubes and out of direct contact therewith, thus avoiding any substantial transfer of heat b convection. In the case of the apparatus red from the top, the outlet at the bottom of the heating chamber discharges into a flue in which an ash pit is provided in the event that powdered fuel is to be burned. Both the burner chamber and the outlet are of less diameter than the heating chamber and extend beyond thc same so that the ends of the tubes may project outside of the heating chamber, entirely out of contact with the hot gases. The products of combustion may pass from the flue to an economizer section in which the hot gases come into direct contact with a. series of tubes in which the fluid to be heated is given a preliminary heating. From the economizer the products of combustion then pass to the stack. A by-pass around the economizer connecting the radiant heat section of the furnace with the stack is controlled by an explosion damper adapted to be opened automatically by the forcel of an explosion in the furnace, or by hand 1n case of a leak or failure of a tube. I have also illustrated a modification of the invention in which the transfer of heat is practically entirely accomplished by radiation and the economizer section is replaced by an air preheater which has for its purpose to preheat the air required for combustion thus permitting a higher flame temperature at the exit of the burner and making it possible to transfer additional heat at high temperature which would have to be transferred by contact at low temperatures if no air pre eater were used.

It will he understood that the heater is applicable to a wide variety of uses such as the generation of steam, heating the gases, etc. and I therefore do not desire to be confined to any particular use or construction beyond that set forth in the appended claims.

ln the accompanying drawings, in which like reference numerals denote like parts throughout the several views thereof:

Figure 1-is a vertical longitudinal section of a pipe still constructed in accordance with my invention;

Figure 2-is a horizontal section taken on the line 2--2 of Figure 1;

Figure 3-is a detail plan view of a portion of the upper tube sheet;

Figure 4-is a detail plan view of a portion of the lower tube sheet; and

Figure 5-is an elevation partially in section of a modified form of my invention.

Referring more particularly to the drawings, a steel shell 10 preferably c lindrical in form is supported at its base by s iort posts or columns 11 which are suitably secured in a foundation 12. An annular iiange 13 is secured to the lower edge of the shell 10 and supports the weight of the heat insulatin lining 14 and the inner refractory lining 1. A steel cylindrical ring 16 of somewhat less diameter than the shell 10 is disposed below the shell 10 and supported upon the foundation 12 by means of a lower flange 17 secured thereto; an upper outwardly extending Harige 18 is secured to the upper edge of the ring 16 and is disposed in substantially the same horizontal plane as the Harige 13 on the shell 10. The ring 16 encircles the outlet 19 for the products of combustion.

The upper edge of the shell 10 supports the upper tube sheet 20 which is provided with an integral depending flange 21 at its outer edge and an integral upwardly extending flange 22 at its inner ed e. The tube sheet 20 is preferably formed o a. plurality of segmental sections, one of which is illustrated in Figure 3. The depending flange 2l is secured directly to the shell 10 and the flange 22 is secured to a rin 23 to which is also secured the framewor 24 which su ports the burner cone 25 of the furnace. '1 e upper ends of the bars comprising the framework 24 are secured to a ring 26 which supports the centrally located burner casing.

It will be noted that by this construction the metal shell 10 supports practically the entire weight of the furnace structure, and that the upper tube sheet 2O together with the ring 23, the framework 24 and the ring 26 form, in effect, a self supporting arch, the stresses of which are transmitted to and borne directly by the shell 10. Inasmuch as this shell is cylindrical and takes the greater portion of the strain edgewise, it is apparent that a large factor of safety may be secured with the use of a comparatively small amount of steel work. It is to be understood, of course, that the shell 10 need not be a single piece of metal, and that other equivalent supporting means might be employed, such as for example, a squirrel cage construction comprising Wide bands of metal at the top and bottom of the furnace rigidly joined together by vertical bars. The word shell therefore as used in the claims, is intended to include such adaptations and modifications.

The oil heating tubes 27 are inserted in apertures in the upper tube sheet 20 and are connected together by couplings 28 having shoulders which rest upon the upper tube sheet 20 so that the tubes are suspended vertically therefrom. The tubes 27 are disposed adjacent the inner refractory wall 15,

etween the same and the products of combastion in the center of the furnace. The lower ends of the tubes extend through apertures in a lower tube sheet 29 which consists of a plurality of flat segments resting upon the. flanges 13 and 18, and are provided with 'couplings 30, both of these sets of couplings having plugs 31 in their ends which may be removed to permit access to the tubes for cleaning.

The burner cone 25 of the furnace is substantially conical in shape and flares out- Wardly at its bottom forming a horizontal shoulder 32. The upper narrow end of the burner cone 25 is provided with an opening 83 in which is inserted a suitable burner 34, the exact construction of which is not illustrated but which may be of any well known type suitable for the particular fuel to be burned. The outlet 19 is provided with an outwardly flaring rounded shoulder 35. Both the burner cone 25 and the outlet 19 are centrally disposed with respect to the tubes and for this reason the hot products of combustion tend to tlow through the center of the furnace away from direct contact with the tubes 27 and to transmit heat thereto mainly by radiation, the shoulders 32 and 35 serving to maintain a blanket of dead or relatively slow movin gases in the nei hborhood oi the tubes. it will also be note that the couplings 28 and 30 joinin the tubes together are disposed outside o the furnace where they are not subjected to the destructive effect of the direct heat of the furnace. The upper ends of the tubes are enclosed in a protecting chamber 36, the top of which is removable to permit access to the tubes for cleaning or replacement.

By this construction of the tubes it will be observed that they are supported solely from' the upper tube sheet, and inasmuch as their expansion is mainly in the direction of their length, they may expand freely without damage to themselves or to their supports. It will be noted also that the tubes are so positioned that ready access may be had to their ends. Thus the lower wall of the heating chamber cooperates with the outlet 19 and the foundation 12 to form an annular recess in which the lower ends of the tubes are located and the usual tools may be readily inserted into this recess to expand the ends of the tubes into the couplings 30 when new tubes are inserted. The segmental construction of the upper and lower tube sheets, together with the fact that the lower tube sheet merely rests upon the flanges 13 and 18, enables the entire section of the tubes to be lifted by a suitable crane if necessary, to permit small repairs to be made to the furnace lining. When inserting new tubes it is merely necessary to cut the old tubes at convenient places, remove the ends from the couplings, lower a new tube into place and expand its end into the coupling with the usual tool for this purpose having rotating rollers.

The outlet 19 of the furnace is connected to an underground flue 40 and an ash pit 41 having a steam ejector 42 for removing the ash is located immediately beneath the outlet 19 and the burner 34. The steam ejector is protected by a fluid cooled grate 43 through which the oil to be heated may be pumped. Provision is thus made for easily and effectively removing the ash when powdered coal or other fuel having considerable solid residue is burned. A manhole 44 having a cover 45 permits access to the ash pit 41, flue 40, and the interior of the furnace.

The fiue 40 connects with an economizer section 50 of conventional construction in which the oil may be preheated in tubes in direct contact with the flue gases.

The flue gases after passing through the economizer section 50 pass through a flue 51 into a stack 52 and are controlled by a damper 53 located in the iue 51. The stack 52 also communicates directly with the flue 40 so that the economizer section 50 ma be bypassed by opening the damper 54. e construction of the damper 54 is such that it will be opened automatically by any explosion in the still or by any other cause creating sudden dangerous pressure of the flue gases so that a quick escape for the products of combustion is provided.

The damper 54 com rises a rotatable shaft 55 mounted in the stac 52 and provided with an external operating handle 56 for hand operation. A collar 57 is rigidl, secured to the shaft 55 within the stack an is connected by means of a pivoted link 58 with the damper 54. The lower end of the damper 54 is provided with a bearing 59 which co-operates with an axis suitably located to cause the damper 54 to pivot about the bearing 59.

A platform having a railing 66 encircles the upper end of the furnace and is supported by the shell 10.

Referring to the modification shown.` in Figure 5 the construction of the furnace and stack is similar to that shown in Fi res 1 and 2, but the economizer section is eliminated and its place is taken by an air preheater of the recuperator type disposed directly' in the flue 40. No explosion damper is shown in this ligure, but one might easily be arranged by constructing a by-pass around the air heater 70 and placing its explosion damper in the by-pass.

The use of the air preheater shown in this modification permits the use of substantially the theoretical quantity of air for complete -100 combustion of the fuel and enables a considerably higher flame temperature to be secured in the heating chamber than has been possible heretofore in other types of furnaces and therefore more radiant heat will 105 be transferred to the heating tubes 27 in this chamber. The additional radiant heat transfer thus secured makes it possible to economically eliminate the economizer section 50 shown in Figure 1.

What I claim is:

1. The method of quickly raising hydrocarbon oils to a high temperature, comprising burning a fuel to create a source of intensive radiant heat and impelling the dame and the 115 products of combustion in a vertical unobstructed path, passing the oil in a series of vertical parallel paths, all of said paths being in substantially uniform radiativerelationtothe source of heat and parallel to the path of the 120 flame and products of combustion, to quickly absorb such heat and reduce the temperature of the combustion gases, withdrawing the gases while maintaining them in substantially non-convective relation to said paths, and 125 passing the gases in convective relation to the air employed for combustion to preheat the same.

2. The method of heatin hydrocarbon oils to a high temperature whic comprises burn- 130 4 means? ing a fuel to create a source of intensive heat and impelling the {iame and the products of combustion in a vertical unobstructed path passing the hydrocarbon oil in a. series of parallel paths, all of said paths being in substantially uniform radiative relation to the source of heat, to quickly absorb such heat and reduce the temperature of the combustion gases, withdrawing the gases While maintaining them in non-convective relation to said paths, and passing the gases in convective relation to the air employed for combustion to preheat the same.

3. The method of quickly raising oil to a desired temperature, which comprises burning a fuel to create a flame as a source of intensive radiant heat and impelling the flame and the products of combustion in a vertical unobstructed path, passing the oil in radiative relation to the flame and the hot combustion products serially through vertical paths which are parallel to the path of the ame and products of combustion and substantially equidistant therefrom, to quickly absorb radiant heat and reduce the temperature of the products of combustion, While maintaining the products of combustion in substan tially non-convective relation to said paths, passmg the products of combustion in convective relation to the air employed to preheat the same and supplying to the burning fuel substantially the theoretical quantity of air necessary for complete combustion of the fuel.

In Witness whereof I have hereunto set my hand this 31st day of October 1928.

- LUIS DE FLOREZ.

CERTIFICATE 0F CORRECTION.

Patent No. l, 862, 737.

LUIS de FLREZ.

June 14, 1932.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Page l, lines 3 and`4,

for "tublar" read tubular; page 4, line 5, claim 6, before "parallel" insert the word vertical, and line 7, after "heat" first occurrence insert the words and parallel to the path of the flame and products of combustion; and that the said Letters Patent should be read with these corrections therein that the same may conformto the record of the case in the Patent Office.

Signed and sealed this 4th day of October, A. D. 1932.

(Seal) M. J. Moore, Acting Commissioner of Patents.

4 means? ing a fuel to create a source of intensive heat and impelling the {iame and the products of combustion in a vertical unobstructed path passing the hydrocarbon oil in a. series of parallel paths, all of said paths being in substantially uniform radiative relation to the source of heat, to quickly absorb such heat and reduce the temperature of the combustion gases, withdrawing the gases While maintaining them in non-convective relation to said paths, and passing the gases in convective relation to the air employed for combustion to preheat the same.

3. The method of quickly raising oil to a desired temperature, which comprises burning a fuel to create a flame as a source of intensive radiant heat and impelling the flame and the products of combustion in a vertical unobstructed path, passing the oil in radiative relation to the flame and the hot combustion products serially through vertical paths which are parallel to the path of the ame and products of combustion and substantially equidistant therefrom, to quickly absorb radiant heat and reduce the temperature of the products of combustion, While maintaining the products of combustion in substan tially non-convective relation to said paths, passmg the products of combustion in convective relation to the air employed to preheat the same and supplying to the burning fuel substantially the theoretical quantity of air necessary for complete combustion of the fuel.

In Witness whereof I have hereunto set my hand this 31st day of October 1928.

- LUIS DE FLOREZ.

CERTIFICATE 0F CORRECTION.

Patent No. l, 862, 737.

LUIS de FLREZ.

June 14, 1932.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Page l, lines 3 and`4,

for "tublar" read tubular; page 4, line 5, claim 6, before "parallel" insert the word vertical, and line 7, after "heat" first occurrence insert the words and parallel to the path of the flame and products of combustion; and that the said Letters Patent should be read with these corrections therein that the same may conformto the record of the case in the Patent Office.

Signed and sealed this 4th day of October, A. D. 1932.

(Seal) M. J. Moore, Acting Commissioner of Patents.

5 CERTIFICATE OF CORRECTION.

Patent No. 1,862,737. June 14, 1932.

LUIS de FLOREZ.

It is hereby certified that in Certificate of Correction issued October 4, 1932, in the above numbered patent, the claim 6, in line 3, should read claim 2; and that the said Certificate of Correction shouldbe read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 8th day of November, A. D. 1932.

M. J. Moore,

(Seal) Acting Commissioner of Patents.

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