US2346348A - Heater for fluids - Google Patents

Description

M. W.IBARN|-:s

HEATER FOR FLUIDS Aprilv 11, 1944.

Filed Jan. 26, 1942 ANANOOOOOOOOGOO,

Patented Apr. 11, 1944 HEATER Fon FLUIDS Marion W. Barnes; Chicago, Ill., asslgnor to Unlversal Oil Products Company, Chicago, Ill., a corporation of Delaware Application January 26, 1942, serial No'. 428,239

. Claims. (Cl. 4122-356) The invention isvdirected to an improved form of heater for fluids which is particularly advantageous as applied to heating hydrocarbons to the high temperatures required for their thermal or catalytic conversion,A but which will also be found useful in numerous other applications wherein it is desired to heat one or more streams of uid with relatively high rates of heat input.

The heater herein provided is of the general type employing a plurality of separately fired cells with tubular fluid conduits disposed in each.

cell to receive direct radiant heat from the flames and hot combustion gases passing therethrough and from refractory walls vof the heater over which said flames and hot combustion gases are passed.

The features and advantages of the invention will be apparent to those familiar with the art from an inspection of the accompanying diagrammatic drawing and the following description thereof.

The single figure of the drawing represents a cross-sectio'nal elevation of one specific form of the heater provided by the invention.

Referring to the drawing, the heater here illustrated comprises substantially vertical refractory side walls l and 2, inwardly and upwardly sloping refractory walls 3 and 4 which connect -walls and 2, respectively, with the other vertical refractory outer walls '5 and 6, a floor 1, and end walls not shown.

Interior refractory walls 8 and 9, spaced from each other and from the side walls l and 2, are provided within the heater and extend from the `door to a level adjacent the upper extremity of walls and 2.

The'space within the heaterbetween walls l and 8 comprises a combustion and radiant heatcentral cell. Another bank 20, comprising in this I instance a single row-of horizontally disposed tubes 2|, is located in the upper portion of the heater adjacent the inner surface of wall v3 and a similar bank 22 of tubular fluid conduits 23 is disposed in the upper portion of the heater adjacent the inner surface of wall 4. Still another bank 24, comprising a plurality of superimposed horizontal rows of horizontally disposed tubes 25, is located in the fluid heating zone 26 dened between walls 5 and .6. A flue 21 leading to a suitable stack 28'is provided above zone 26.

The entire furnace structure is mounted upon a suitable foundation which, in this instance,

comprises a.l vertical wall 28 disposed beneath each of the walls I, 2, 8 and 9, a iloor 30, disposed beneath and spaced from .the refractory floor 1, and suitable footings, not illustrated. Burner compartments 3|, 32, 33 and 3H, individual to the respective combustion and heating zones i0, il, i2 and I3, are provided beneath floor 1 and between the walls 29 and suitable partitions 35 and 36 are provided to separate the individual burner compartments from each other.

A horizontal row of burners, one of which is indicated at 3'|, is provided within burner compartment 3| and these burners communicate with combustion and heating zone I0 through firing ports'36 provided in floor 1 adjacent the lower end of wall 8. Fuel is supplied to each of the burners 31 through line 38 and valve 40 and air is admitted in regulated amounts to burner compartment 3i by the adjustment of a suitable damper 4| provided at the mouth `of opening 42v through the adjacent wall 28. The air thus admitted to compartment 8| passes through burners 31 to mix with the fuel and form a combustible mixture which is burned in zone I0 ading zone or redV cell I0, and a separatelyred combustion and radiant heating zone or cell is defined between walls 2 and `9.` A centrallyl disposed cell, comprising the independently red combustion and radiant heating zones |2- and |3, is provided between walls 8A and 9.

A bankl I4, comprising, in the case illustrated,

-a single vertical row of. horizontally disposed tubular uid conduits '|5, is located Within cell Iladjacent the interior surfacel of wall I. Another-.bank I8, comprising in this instance a single vertical row of horizontally disposed tubes |1, is located ain cell l adjacent the inner surface .of wall 2. Another bank i8, comprising, in the case illustrated, two vertically parallel rows of horizontally disposed tubes I9. is located substantially midway between walls 8 and 8 in the jacent the surface of wall 8.v The flames and hot combustion gases issuing from burners 31 and burner ports 38 are directed upwardly at an angle against and over the surface of wallk 8,

heating the latter to a highly radiant condition and direct radiant heat is transmitted from wall 8 and from the flames andhot combustion gases passing thereover to oneside of the tubes I5 of bank Il.

i firing arrangement similar to that above ydescribed with the elements thereofA designated by the same reference numerals 31 and 2in-v clusive is providedfor cell ll, which is ilred independently Aof cell I8 and wherein direct radi- Reflected radiant heat is transmitted from wall tothe opposite side of these tubes.

combustion gases passing thereover to one side of the tubes I1 to bank IB. 'I'he opposite side of these tubes is heated by reflected radiant heat from wall 2.

Another horizontal row of burners, one of which is indicated at 43, is provided in burner compartment 33 for directing flames and hot combustion gases through ring ports 44, disposed in floor 1 adjacent the base of wall 8, upwardly into combustion and heating zone 'I2 over the surface of wall 8 facing tube bank I8, heating the latter to a highly radiant condition. Fuel is supplied to each of the burners 43 through a line 45 and a valve 4B and air for combustion of the fuel is admitted in controlled amounts, by the adjustment of damper 41. to burner compartment 33 through openings 48 and 49 in walls 29. A similar ring arrangement, wherein corresponding portions are indicated by the same reference numerals 43 to 49 inclusive, is provided for combustion and heating zone I3 to direct flames and hot combustion gases upwardly over the surface of wall 9 facing tube bank I8.

The tubes in the opposite rows of bank I8 are arranged in staggered formation and are so spaced that each tube is heated on one side by direct radiation from the surface of wall 8 and from the flames and hot combustion gases passing thereover and on its opposite side from the surface of wall 9 and the flames and hot combustion gases passing thereover. The tubes in the right-hand row of bank I8 are, of course. partially shielded from radiant heat transmitted from the wall 8 and from the flames and hot combustion gases in zone I2, while the tubes in the left-hand row of bank I8 are partially shielded from radiant heat transmitted from wall 9 and from the flames and hot combustion gases passing through zone I3. Thus, by independent firing of zones I2 and I3. a considerable degree of independent control may be exerted over the rates of heat transmission obtained in the right and left-hand rows of bank I8. The heating conditions employed in zones III and II and the rates of heating obtained in banks I4 and I3 are made entirely independent of each other and of the heating conditions employed in zones I2 and I3 by the provisions for independently firing each of the zones Ill and I I. Thus, an unusually high degree of flexibility is provided in this heater and by the selection of suitable specific paths of flow through the tube banks and a suitable seouential or parallel arrangement of the tube banks in said flow. a wide variety of heatinar curves is obtainable for the fluid undergoing treatment. and the type of heat treatment desired may be selected to suit requirements. When desired, it is also easy to obtain either la different type of heat treatment or substantially the same heat treatment or two or more separate streams of fluid with the heater herein provided.

Combustion gases which have given up a substantial portion of their heat to the respective tube banks I4, I6 and I8 are discharged from each of the independently fired combustion and heating zones I8, II. I2 and I3 into the space between walls 3 and 4 and supply both radiant and convection heat to the tubular elements of banks and 22. "I'he tubes of these banks receive direct radiant heat on one side from the hot combustion gases and receive reflected radiant heat on their opposite sides from the respective walls 3 and 4. Heating conditions obtained in bank 20 are, of course. influenced to a greater extent by the combustion gases from zones III and I2 than those from zones II and I3, while the heating conditions obtained in bank 22 are influenced to a greater extent by the combustion gases from zones II and I3 than from zones I0 and I2, so that a considerable degree of independent control is also obtainable over the heating conditions employed in bank 20 as compared with that obtained in bank 22 and vice versa.

The total combustion gases from zones II'I, II, I2 and I3, after supplying heat to the tubes of banks 20 and 22, pass upwardlythrough fluid heating zone 26 in intimate contact with the tubes of bank 24 in this zone and supply a considerable portion of their residual heat thereto. The combustion gases are thence directed through ilue 21 to stack 28.

The invention is not limited to any specific path of flow of fluid through the various tube banks nor to any specific sequence of flow through the several banks. Ordinarily, adjacent tubes in each bank will be connected in series at their ends by suitable return bends or headers, not illustrated, but it is also within the scope of the invention to connect portions or all of the tubes in any bank for parallel flow or to connect severalV banks for the parallel flow of separate streams of the same or different fluid therethrough. It is also Within the scope of the invention to dispose the tubular elements of any or all of the various banks adjacent the side and interior walls in a vertical rather than a horizontal position and the tubes in either or both of the banks adjacent the sloping walls'of the heater may extend lengthwise from adjacent the top to adjacent the bottom of the sloping wall rather than from end to end thereof. As previously mentioned, a wide variety of advantageous flow arrangements are possible in the improved form of heater herein provided and may be selected within the skill of one familiar with the art and correlated with the firing conditions employed in the independently fired combustion and heating zones to suit requirements.

Although the specific form of heater illustrated in the drawing is up-flred `with a general upward flow of combustiongases throughout the heater. it is entirely within the vscope of the invention to invert the furnace structure and re in a downward direction with a general* downward flow of combustion gases through the heater.'

The invention also contemplates a two row arrangement instead of a single row of tubes in any or all of the banks I4, I6, 20 and 22 and. when desired, a single row of tubes or more than two rows of tubes (usually three or four rows) may be employed in bank I8 instead of the two row arrangement shown in the drawing. These and numerous other variations from the specific structure illustrated will be evident to one familiar with the art.

I claim as my invention: n

1. A heater -for fluids comprising, in combination, refractory side and end walls, a floor and a roof, a pair of substantially vertical, refractory, interior lwalls spaced from each other to provide a central radiant heating cell therebetween and spaced from said side walls to provide a side radiant heating cell between each of said interior walls and the adjacent side wall, a substantially vertical bank of tubular fluid conduits disposed substantially midway between said interior walls in the central cell, a substantially vertical bank of tubular fluid conduits disposed in each of the side cells adjacent one of said re-. fractory walls thereof, independent firing means for eachof said cells, means for directing flames and hot combustiongases from the firing means for said side cells upwardly therethrough over .the surface of that refractory wall thereof opposite said tube bank disposed therein, means for directing flames and hot combustion gases from the firing means for said central cell upwardly cover the refractory surfaces of said central walls facing said tube bank in the central c'ell, a convection heating zone above and in alignment with said central cell, heating tubes disposed in said convection zone, and means for passing combustion gases from said side cells and central cell through the convection heating zone.

2. A heater for fluids comprising, in combination, refractory side walls, a pair of substantially vertical refractory interior walls spaced from each other to provide a central radiant heating cell vtherebetween and spaced from said side walls to provide a side radiant heating cell between each of said interior walls and the adjacent side l wall, a substantially vertical bank of tubular fluid conduits disposed in said central cell substantially midway between the interior-walls, a substantially vertical bank ofl tubular fluid con duits disposed adjacent the side wall in each of said side cells, burner means disposed adjacent one end and on opposite sides of each of the central walls for directing ames and hot combustion gases thereover, a convection heating zone in vertical alignment with said central cell vand heating tubes disposed therein, and means for passing combustion gases from said side cells and central celll through the convection heating zone.

3. A heater for fluids comprising, in combination, a pair of substantially vertical refractory side walls and a pair of substantiallyv vertical `refractory end walls defining the lower portion Y of the heater, refractory sloping walls extending .therebetween and spaced from the first named side walls to provide a side radiant heating zone between each of said interior walls and the adjacent side wall, a substantially vertical bank of tubular uid conduits disposed in said central cell substantially midway between the interior walls, a bank of tubular fluid conduits disposed in each of said side cells adjacent the first-named refractory wall thereof,- a bank of tu-bular fluid conduits disposed adjacent and substantially parallel to each of said sloping walls, a bank of tubular fluid conduits disposed within said fluid heating zone, burners disposed adjacent the base and on opposite sides of each of the interior walls for directing flames and hotcornbustion gases upwardly over. the opposite surfaces thereofthroughl said cells, said fluid heating zone being in direct communication with' each of said cells through the space defined between said A'sloping walls.

4. A heater for fluids comprising a first pair of spaced, substantially vertical refractory walls. a'second pair vofsubstantially vertical refractory walls spaced from each other and disposed between and spaced from the first-named walls to form an intermediate heating cell and an additionalheating cell on each side oi' the intermedlate cell, a bant: si heating tubes in said intermediate cell substantially midway between said secondv pair of walls, heating tubes in each of said additional cells adjacent one of said first pair of walls, and iburner means disposed adjacent an end and on opposite sides of each of the walls of said second pair for directing hot combustion products over both sides of each of the last-named walls.

5. In a furnace having lrefractory side walls, the combination of a pair of substantially vertical refractory interior walls spaced from each other to form a central heating zone therebetween and spaced from the side walls to form a side heating cell between ,each of the interior walls and the adjacent side wall, a bank o1" heating tubes in said central cell substantially 45 midway between said interior walls, heating tubes in each of said side cells adjacent one of said side walls, and burner means disposed adjacent an end and on opposite sides ofeach of said interior walls for directing hot combustion products over 50 both sides of each of the interior walls.

MARION W. BARNES.

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