US2737159A

US2737159A - Baffle and tube arrangement in catalytic reforming heater

Info

Publication number: US2737159A
Application number: US381574A
Authority: US
Inventors: Lawrence J Mccarthy
Original assignee: Chemical Construction Corp
Current assignee: Chemical Construction Corp
Priority date: 1953-09-22
Filing date: 1953-09-22
Publication date: 1956-03-06
Anticipated expiration: 1973-03-06

Description

March 6, 1956 1.. J. MCCARTHY BAFFLE AND TUBE ARRANGEMENT IN CATALYTIC REFORMING HEATER 2 Sheets-Sheet 1 Filed Sept. 22, 1953 a H M r m MW m T \I- UN, H H. .IwHHnWJHv m g lllllll O H v. a a H n a A I p M .3 1 wln. b 1 i: w .r L e h Q 3 INVENTOR.

HTTUF/ IFY' March 6, 1956 J. MCCARTHY BAFFLE AND TUBE ARRANGEMENT IN CATALYTIC REFORMING HEATER 2 Sheets-Sheet 2 Filed Sept. 22, 1955 ATTORNEY United States Patent '0 RAFFLE AND TUBE ARRANGEMENT IN CATALYTIC REFORMING HEATER Lawrence J. McCarthy, Englewood, N. J., assignor to Chemical Construction Corporation, New York, N. Y., a corporation of Delaware Application September 22, 1953, Serial No. 381,574

Claims. (Cl. 122-333) This invention relates to improvements in fluid heating apparatus of the type disclosed in my prior application Serial Number 22,732, filed October 25, 1948, now U. S. Fatent No. 2,660,519 dated November 24, 1953, and my copending application Serial Number 225,793, filed May ll, 1951. More particularly, the present invention relates to an improved construction and arrangement of battles for use in combination with such heating apparatus for directing and controlling the flow'of combustion gases through the radiant and gas collecting chamhers of the furnace to the flue or outlet to thestack.

In my prior applications, referred to above, the upper portion of the furnace or heater is provided with a partitic-n which divides the furnace into a lower radiant heating chamber and an upper gas-collecting chamber. The partition has an opening in the center from which radiate a plurality of elongated openings extending to the sides of the furnace through which vertical heating tubes pass, In a preferred form of heater the gas-collecting chamber is substantially cruciform in shape and is formed by the provision of vertical walls adjacent the edges of the elongated openings in the partition which extend upwardly to the top of the chamber. The flue or outlet to the stack is located in the side wall of the heater adjacent the peripheral end of one of the arms of the cruciform-shaped chamber. To provide for equalization of draft through the elongated openings the crosssectional area of each opening is progressively reduced by extended portions of the partition, in the form of nose tile, which protrude into the openings. Thus, the crosssectional area of each opening is progressively reduced from the side walls of the heater towards the center opening except for the opening adjacent the flue or stack outlet which increases progressively from the side walls of the heater towards the center.

While the use of nose tile in the manner described provides an effective means for equalizing the draft in the diiferent compartments of the furnace, their use under some conditions has been found to be expensive. This is particularly true with increase in size of the furnace. nornical distribution of combustion gases into the gascollecting chamber is secured by substantially completely closing the central opening of the partition. This is for the reason that the presence of such opening ,in the partition was found to increase both the cost and'the difiiculty of obtaining equalization of the draft by means of nose tile projections at this point.

it has also been found that removable metal bafile plates may be used instead of the more expensive nose tile and that the combination of such baffles in the arm of the gas-collecting chamber leading to the stack, coupled with closing of the central opening to the gas-collecting chamber, referred to above, will provide substantial equalization of draft and distribution of the heat of the combustion gases in the furnace.

It is, accordingly, an objectofthis invention to provide an improved andinexpensive hafliearrangernent and It has been found that satisfactory and more eco- ,5 ice construction which may be used in connection with large heaters of thetype' described as Well as smaller ones and which will effectively control the w of combustion gases so as to obtain a high efficiency and substantial equalization of draft and distribution of heat throughout the furnace.

Another object of the invention is the provision of a furnace structure and bafiie means arranged so as to enableplacement and replacement of baffle members of difierent characteristics in different locations between the radiant heating sections of the furnace and the gas-collecting chambers to more readily control the distribution of combustion gases in the different parts of the furnace, thereby obtaining uniform temperatures throughout the furnace and enabling eflicient furnace operation under difierent conditions.

These objects and others, as will become apparent hereinafter, are accomplishedby the provision of a relatively narrow ledge or shelf of substantially uniform width extending from opposite side walls of the gascollecting chamber into the openings at the level of the partition, and the provision of specially designed bafiie plates, preferably made of chrome-nickel steel, adapted to rest on the ledge and bridge certain portions of the openings to'contr'ol the passage of combustion gases into thegas-collecting chamber. The shelf or ledge may be simply a continuation of the partition structure itself. The baffie's, which are made in sections, are provided with matching cut-out portions to enable them to fit closely around the tubes in some relations and thus substantially entirely prevent theipassage of combustiongas while inv other relations they are designed to provide merely restricted openings for limited and accelerated passage of gas around the tubes into the gas-collecting chambers.

For a further and more detailed description of the invention reference is made to the accompanying drawings whereina Figure 1 is a side view of the heater partly in vertica section taken alongline 11 of Figure 2.

Figure 2 ista horizontal-sectional view taken along line 2-2 of Figure 1 and Figure 3 .is an expanded detail in perspective of a bafile arrangement such, as shown in Figures 1 and 2.

Referringto the drawings, Figure 1 shows a furnace assembly in which afoundation 1 formed of a suitable structure of I beams supports cylindrical load bearingwalls 2 which enclose a radiant heating .sectionfi, a gas-collecting section indicated generally by the numeral 4, and a space 5.. In space 5 are located'the suspension means for the heating tubes 6 and inlet and outletmanifolds (not shown) for delivering fluid to and from the heating tubes. The heating or catalytic tubes 6 are hung vertically, preferably in banks, in cruciform arrangement as shown in Figure'2, and extended downwardlythrough both the gas collectingchamber 4 and the radiant heating chamber 3, dividing both chambers into four heating cells each. The tubes are free at their lower ends to expand into the wells7, in the floor of the furnace.

Transversebeams -9 mounted at the top of the load bearing-walls '2 and supported by them extend across the central portion of the furnace. Preferably two transverse beams are used and attached to them at one end and to :the load bearing walls 2 at the other are support angles.8 which together *with the beams frame "the top of thefurnace. On this structure cover plate'tla rests. Suspendedtrom beams 9 varetension members 10 which extend-downwardly intothe central portion of the fur nace. An upper set of transverse beams 11 and alower set 12 are attached at their inner ends to the suspension members loand at their outer ends to the load bearing walls 2.

The heating tubes in the furnace are adapted to be suspended or hung from beams 11 by any suitable method or by the manner disclosed in my prior application Serial Number 225,793, filed May 11, 1951, reference to which is hereby made for a detailed showing of one such arrangement.

Beams 11 and 12 are further braced by I beams 20 which also provide support for the side walls and top 16 of the gas-collecting chamber. Tension members 10, I beams 20, and the transverse beams 11 and 12 cooperate with the load bearing walls 2 to outline the general contour of the gas-collecting chamber which in turn takes the cruciform shape of the tube bank arrangement as shown in Figure 2.

As there shown, the gas collecting section of the heater consists of a central portion from which radiate the four gas-collecting

sections

21, 22, 23 and 24. Section 24 as indicated is adapted to be connected to a stack outlet 2411 or to a preheater for final discharge of the combustion gases from the furnace. Since in the embodiment of the invention illustrated all the combustion gases from the furnace must exit through section 24, this section may be made wider than

sections

21, 22 and 23 so as to have a greater cross-sectional area to accommodate the greater volume of gas.

The walls 13 and the ceiling 14 of the radiant heating section 3 and the walls 15 and top 16 of the gas-collecting chamber 4 are composed of suitable refractory material which protects the load bearing wall 2 and the suspension means including

members

8, 9, 10, 11, 12 and from the hot products of combustion. To cool the suspension means, ventilating ports 17 are provided in the space 5 to permit circulation of air therein. Rows of gas burners 19 are located in the fioor of each of the heating cells as indicated in dotted lines in Fig. 2 of the drawings. Bustle pipe 18 surrounds the furnace at the bottom and supplies preheated air to these burners by means of a manifold under each cell. The location and structure of the manifold and burner are shown in Fig. 6 of my U. S. Patent No. 2,660,519 referred to above.

In order to provide for substantially uniform draft conditions and heating of the tubes in the furnace, the roof or ceiling 14 of the radiant heating chamber is extended a short distance into the cruciform-shaped entrance to the gas-collection section to provide a narrow ledge or shelf running along each side of the entrance. This is for the purpose of supporting a plurality of baffle plates as illustrated in Figure 2. One form and arrangement of baffle plates found to be particularly advantageous is shown in greater detail in expanded relation in Figure 3. Referring to Figures 2 and 3, the entrance from the radiant heating section 3 to the central portion of the gascollecting section is adapted to be closed by bafiie plates 26 and 27. These are supported by resting on ledges 28 of

bafiie plates

29, 30, 31 and 32, which plates are in I turn supported on shelf 25 in each of the arms or

sections

21, 22, 23 and 24 of the gas-collection section. The baflies are provided with semi-circular, matching, cutout portions as shown for fitting closely around heating tubes.

Baffle plates

32, 33, 34, and 35 are adapted to rest on ledge 25 in exit section 24. These baffles which are not interfitting but may merely abut one another, are provided with enlarged, matching cut-out portions 36 for fitting around pipes 6. As shown, these latter baffles restrict or limit the passage of combustion gas from the radiant section into section 24, but do not block it off entirely. Thus, the distribution of hot combustion gases passing from the radiant heating section into the gas-collecting section is adjusted or controlled by the baffles to provide for substantial equalization of temperature conditions and uniform heating of the tubes throughout the gas-collecting chamber as well as in the radiant heating chamber.

Use of the baffles constructed and arranged as shown, in combination with heaters of the type described, provides an effective and inexpensive construction for obtaining uniform heating of the tubes in both the radiant and connection heating sections of the furnace.

Removal and replacement of the bafiles may be through inspection or cleanout doors 37 in the side walls of the gas-collecting section and through explosion doors (not shown) in the walls 2 of the radiant heating section.

I claim:

1. In a fluid heating furnace having a combination a lower radiant heating chamber formed by vertical side walls and a floor having fuel burners therein, an upper convection chamber having a top and side walls and being smaller in cross-sectional area than said lower chamber and surmounted thereon, a stack outlet in a lateral peripheral portion of said upper chamber, a horizontal partition extending inwardly over the major area of said lower chamber from the side walls thereof and constituting a ceiling therefor, a central opening in said partition, a plurality of elongated openings in said partition extending from said central opening toward the side walls of said lower chamber, one such elongated opening being adjacent said stack outlet, and a number of vertical tubes extending through said openings from the floor of said lower chamber to the top of said upper chamber, the improvement which comprises a bafile surrounding the tubes passing through said central opening and fitting closely around said tubes to prevent the longitudinal passage of said gases through said opening, and a plurality of bafiies having matching cut-out portions across said elongated opening adjacent the stack outlet, the cut-out portions of said baflies being of such size as to permit vertical flow along the tubes adjacent thereto of quantities of gases predetermined to maintain uniform temperatures in said upper convection chamber.

2. A fluid heating furnace comprising in combination a lower radiant heating chamber formed by a floor and substantially vertical side walls surmounted by an upper convection heating chamber having a top and side walls and being smaller in cross-sectional area than said lower chamber, a horizontal partition constituting a ceiling for said lower chamber, said partition extending inwardly from the side walls of said lower chamber to form elongated openings for establishing communication between the lower chamber and the upper chamber and having extended portions on their inner edges forming a narrow shelf, a number of vertical tubes extending from the floor of the lower chamber through said openings in the partition to the top of the upper chamber, fuel burners in the floor of said lower chamber adjacent to said tubes, a stack outlet in the side wall of said upper chamber adjacent the end of one of said elongated openings and bafile means in said opening adjacent the stack outlet, said baffie means resting on said extended portions of the partition and bridging opposite sides of said elongated opening for reducing the cross-sectional area of flow of combustion gas from the radiant heating chamber through the open ing into the upper convection heating chamber.

3. A fluid heating furnace comprising in combination a radiant heating chamber and a gas-collecting chamber, said heating chamber being formed by a floor and cylindrical side wall and having a horizontal partition constituting a ceiling, said partition having a common opening in the center thereof and a plurality of elongated openings each connected to the common opening and radiating therefrom toward the cylindrical side wall, said gas-collecting chamber being positioned above the radiant heating chamber and having a top and side walls, said side walls extending upwardly from the partition adjacent the elongated openings to the top of said gas-collecting chamber whereby the latter is in the form of a corresponding plurality of radiating sections, a plurality of tubes extending from the floor of the radiant heating chamber through the elongated openings into the gas-collecting chamber, fuel burners in the floor of the radiant heating chamber for heating the tubes, means extending inwardly of said side walls of the gas-collecting chamber at said openings for supporting baffle members, a stack outlet in a side wall of the gas-collecting chamber adjacent to the end of one of said openings, baflles in said gas-collecting chamber on said bafile supporting means for reducing the flow of combustion gas from said radiant heating chamber through the opening adjacent to the stack outlet; and baifies in said common central opening supported by said bafile supporting means for substantially completely closing said opening.

4. A fluid heater comprising in combination a radiant heating chamber and a gas-collecting chamber, said radiant heating chamber being formed by a floor and cylindrical side wall and having a horizontal partition constituting a ceiling, said partition having a common opening in the center thereof and a plurality of elongated openings, each connected to the common opening and radiating therefrom toward the side wall, said gas-collecting chamber being positioned above the heating chamber and having top, side and end walls, said side walls of the gas-collecting chamber following the general contour of said openings, but being spaced from the edges of said openings and extended upwardly from the partition to the top of the gas-collecting chamber, whereby the latter is in the form of a corresponding plurality of radiating sections, a. plurality of tubes extending from the floor of the radiant heating chamber through said elongated openings into the gas-collecting chamber, fuel burners in the floor of the radiant heating chamber adjacent the tube for heating the tubes, one of said radiating gas-collecting sections leading to a stack outlet in its end Wall, and bafiles resting on said partition and bridging said central opening and said elongated opening in the gas-collecting section leading to the stack outlet for substantially completely closing said central opening and reducing the area of said elongated opening between the central opening and the stack outlet so as to provide substantially uniform distribution of draft throughout the heater.

5. The subject matter of claim 4 wherein said gascollecting section leading to the stack outlet is of greater cross-sectional area. than the remaining gas-collection sections.

References Cited in the file of this patent UNITED STATES PATENTS 2,105,500 Parsons Jan. 18, 1938 2,211,903 McCarthy Aug. 20, 1940 2,514,279 Gliber July 4, 1950 2,672,849 Fruit Mar. 23, 1954