Патент USA US2126724код для вставки
Aug. 16, 1938. ' 2,126,724 A. J. BOYNTON ' FURNACE AND THE OPERATION THEREOF Filed Aug.‘ ‘1. 1936 2 Sheets-Sheet 1 . . E H 3 m F Z 5l 4 9 5r 5 5I I5 15 4IIIIIIIIIIIIII _ IIIIIIIIIII ‘ 4 v ' Jrf/wr J50 1, A. J. BOYNTON 2,126,124 ' FURNACE AND THE OPERATION THEREOF Filed -Aug;._ 1, 1936 v 2Sheets-Shégt 2 - “VIII/1111” Patented Aug-716,119.38 I I ’ 2,126,724 UNITED STATES»2.126.124PATENT OFFICEX ' - ‘FURNACE AND THE OPERATION manor‘ Arthur J. Boynton, Chicago,'Ill., assignor to H. A. Brassert‘ & Company, Chicago, Ill.,. a corpora’ tlon of Illinois '7 Application August 1, 1936, Serial-No. 93,804 _ 13 ‘Claims. The present invention relates to improvements in furnaces and the operation thereof. More particularly the present invention relates to industrial furnaces operating on gaseous fuels containing hydrocarbons. Among such fuels may be mentioned coke oven gas, natural gas, and mixtures of either of these gases with blast fur nace gas. The invention is equally applicable to _10 gurnaces using othergases containing hydrocar ons. . - It has long been‘recognized that heat transfer from the products of combustion in a furnace or (Cl. 263-15) ‘ thereby‘impartluminosity to the flame. Accord ing to prior constructions and prior methods, re generation under these conditions involves cer tain expensive, and undesirable constructional features and imposes limitations on the opera-f tion. For example", the port through which gas passes to an industrial furnace is ordinarily small in cross sectional area in comparison with the air port. At the outgoing end of the furnace, therefore, the exit ‘gases tend. to pass throughv 10 the air port .to the air regenerator and to heat up this regenerator to a higher temperature than ' _ the likeis greatly promoted by luminosity of the desired, while the heating of the gas regenerator 15 ?ame. Luminoslty'results in absorption of heat ' is less than is required for the desired cracking as a result of radiation. In the absence of lu minosity, heat is transferred by conduction, and to accomplish a predetermined result a temper ature is required within the furnace much higher operation. In connection with the gases ordi 15 narily used, the cracking of hydrocarbon gases requires a temperature in excess of 2000 deg. F., and such a temperature is not usually obtainable than where luminosity exists. ' The result of lack ' from the amount of gas issuing through the rela of luminosity is decreased e?iciencyin furnace operation. , . , . Luminosity of a?ame is understood to result from the presence within the fuel stream of 25 minute particles of solid carbon. These particles become heated to incandescence and give to the ?ame its luminous appearance, at the same time radiating heat. ’ > ' tively small gas ports. It has been suggested, Ni where the practice of regenerating the gas to cracking temperature is followed, to provide the furnace with removable gas ports to permit the \ necessary increased ?ow of outgoing gases into the gas regenerator. In addition to the incon venience and expense of a removable port and the necessity of-maintaining a minimum tem-. Fuel containing hydrocarbons may be made to ~ perature in the gas regenerator, there are inci 30 burn with a luminous ?ame by the decompositionv dental disadvantages connected with the practice of some or all of the contained hydrocarbons _ of heating a mixture of coke oven gas and blast prior to combustion. Such decomposition, often called cracking, results in the formation within. furnace gas in a regenerator. Among these dis advantages is the loss of gas by reversal, since a the gas of solid carbon particles-capable of radia~ , regenerator ?ow of gas goes to the chimney, at ytion and of producing a luminous ?ame. The each reversal. The loss just mentioned may be 35 present invention relates to novel means for pro partly overcome by shutting off the more valu ducing cracking in the operation of an industrial able coke oven gas before reversal, but this neces furnace and the luminosity attendant thereto. sity is an undesirable feature. ‘ ' The present invention will be described in con Among objectionable characteristic of this 40 nection with furnaces such as are employed in practice is a certain danger of explosion during various gases, among which may be gas resulting from liquid fuels such as tar and oil for the crea of high ‘calori?c power. Furthermore, it is nec-v essary‘ to maintain a velocity above a certain the manufacture of steel. Such furnaces employ 35 reversal whichv attends the use of a gas mixture tion of the necessary heating and melting eifect. ’minimum within the gas regenerator, if cracking is taking place therein, in order that the particles 4 It is common practice to preheat such gases. in .regenerators. Another example of the type of gas which is usedis a mixture of coke oven gas and blast furnace gas. Such gases are common ly available at steel works and are frequently 50 wasted except in connection with the manufac ture of steel. The purpose of regeneration of the fuel gas is, in part, to recover the heat from the outgoing waste gases'by raising the temperature of the ingoing fuel. A second and very import ant ob‘ject is, however, to crack the hydrocarbons, .55 chie?y methane, in the gaseous .mixture, and of solid carbon may be swept along with the gas 45 stream and not deposited in the checkerwork of the regenerator. According to the prior sugges tions referred ‘to, the regenerator must be de signed for the double purpose of heating and of _ carrying over into the furnace all of the solid 50 particles of carbon. In short, the objection to the prior suggestions in connection with the cracking of the gas by regeneration are of such consequence that they have resulted in the aban donment of gas regeneration in certain localities, 55 2 2,126,724 Figure 7 is a view similar to Figures 2 and 4 the operators preferring to use cold gas, for the reason that the added simplicity, together with the reduction of cost of repairs and reduction of but showing another modi?cation. eral H indicates as a whole an open hearth fur the loss of gas, more than offsets ‘the nominal 3 thermal bene?t ’ of regeneration. ' Referring first to Figures 1, 2 and 3, the num nace, this furnace having been chosen for pur . Where coke oven gas unmixed with blast fur nace gas is used in furnaces of the type being discussed, regeneration of the gas is ‘usually not practiced, but liquid fuel such as oil or tar is 10 employed as a second fuel, the reason for the use of this liquid fuel being, in considerable measure, to furnish luminosity to the ?ame. The advisability of gas regeneration varies with . poses of illustration as being typical of a regenera- . tive reversible furnace. The numeral I2 indicates a gas regenerator and the numeral l3 indicates an air regenerator cooperatively associated with the furnace II in the manner well understood by 7 those skilled in the art. The numeral i4 indicates an uptake from the gas regenerator I2 communi cating through the port IS with the hearth of the the gas, and, inversely, with the volume of air furnace. The numeral it indicates a pair of up oven gas requires about ?ve volumes; producer from the top of the air regenerator iii to the cracking chamber ita, preferably located on the outside of the furnace. Said'cracking chamber 20 i8a is located between the elbow is communi cating with the pipe [8 and the elbow‘ 20 com municating with the gas port l5. Also communi cating with the elbow i9 is the pipe 2| ‘for con necessary to burn a unit volume of gas. Natural . takes from the air regenerator l3 leading to the gas requires somewhat more than ten times its air port i1, through which communication is had own volume of air for complete combustion; coke to the hearth of the furnace. A pipe i8 leads gas or blast furnace gas requires a much smaller 20 ratio of air to gas, the requirement of blast fur nace gas being somewhat less than the volume of the gas itself. It is ‘well understood, therefore, that the relative advantage of regeneration of gas for the sake of increased temperature is a minimum with natural gas and a maximum with ducting fuel gas, such as coke oven gas or other hydrocarbon gas, to the cracking chamber l8a. blast furnace gas. An object of the present invention is to provide As so connected, said pipe 2| will increase the an improved construction for industrial furnaces > ?ow of air from the air regenerator I: by aspira or the like whereby the cracking of hydrocarbon tion. The pipe I! communicating from the air regen 30 gases for use in such furnaces may be ac complished eillciently. _ erator I3 is provided with the regulating valve'22, ‘ . A further object is to provide apparatus of the kind just referred. to having means for cracking hydrocarbon gas by preliminary combustion of a portion of the gas to raise the temperature of the entire mass of fuel gas and products of com bustion to a cracking temperature. A further object is to provide improvedPap paratus of the kind referred to in which hydro carbon gas may be used in mixture with blast furnace gas and in which the blast furnace gas may be regenerated, to the end that it will be introduced hot into the gas port of the furnace. A further object is to provide a construction of 45 the kind immediately above referred to in which gas ports of ordinary construction may be em ployed- ‘ . A further object is to provide an improved method of operating an industrial furnace where which is adapted to shut’ o? completely com munication between the cracking chamber Ilia ' and the air regenerator [3. For the control of said valve 22, a thermocouple is provided, in dicated by the numeral 23, which thermocouple communicates with the interior of the elbow 20. Said thermocouple 23» is connected to the con troller 24, which in turn is connected to the op erating cylinder 25 for operating said valve 22. 40 In operation, the thermostat 23 will control tem peratures at the'entrance of the cracking cham ber Ila at the minimum at which satisfactory cracking takes place, and the gases entering the port I! by way of said cracking chamber I8a will 45 be‘cracked by partial combustion in said crack ing chamber, to a sufficient extent to provide a luminous ?ame. At the ‘same time, excessive combustion of the gas delivered through the pipe by the desired luminosity of ?ame may be ac 2| is avoided. . Though a thermostatic control for complished emciently and'at relatively low cost. the valve 22 has been shown, it will be under stood that any other control means may be used if preferred. ,By reason of the construction referred ,to, a saving in original and maintenance costs is pro 55 A further object is to provide a furnace con struction and an improved method of furnace operation well adapted to meet the needs of com mercial service. Further objects will appear as.the description proceeds. . - Referring to the drawings Figure 1.is a top plan view, more or less dia grammatic in its nature, illustrating‘a portion of an industrial furnace embodgng the principles of the present invention; I g ‘ , Figure 2 is a sectional view takemalong the plane ‘indicated by the arrows 2-'—2 of Figure 1; _ 65 Figure 3 is an end‘ view taken in the direction of the arrow I of Figure 1; Figure 4 is a view similar in many respects to Figure 2 but omitting the gas regenerator of Figure 2; ' Figure 5 is a sectional view on an enlarged scale illustrating a gas port which may be used in the practice of the present invention; ' _ ' Figure 6 is a view taken. along the plane indicated by the arrows 6-6 of Figure 5; and vided, together with good thermal performance due to regeneration of the blast furnace gas in the regenerator l2. It will; be understood that wherever in this specification or in the claims the term "coke oven gas” is used, it will apply with equal correctness to natural gas or any gas containing hydrocarbons capable of being cracked through heat. The term “hydrocarbon gas” is ‘ intended to be generic to the gases referred to - in this paragraph. 65 Figure 4 illustrates‘ a construction in which the gas regenerator is omitted, a single fuel gas being employed, which gas contains hydrocarbons. Where such a fuel as natural gas or coke oven gas is to' be used, it is'not necessary or desirable to 70 regenerate the gas, since regeneration of the air will pre-heat a very large proportion of the mix ture of air and gas which unite in the furnace. As indicatedabove, however, it is extremely,v de'-" sirable to obtain luminosity in the ?ame. - It is a ' * it 2,120,724. 3 .' also desirable to give a shape to the mixture of) as a result of combustion of the outer layer of combustible gas issuing from the port and to de the gas body. The port 36 is’provided with the termine its velocity. . ' _ i ' valve 32, which may be controlled by a cylinder In Figure 4 the furnace il includes the air re generator l3. Said air regenerator i3 is con 25 responsive to conditions at any preferred point, ‘ as for example in the port i5. nected through the‘pipe 26 to the cracking cham - ' Though a preferred embodiment of the present invention has been described in detail, many ber 26a. I The pipe 21 leads from the cracking chamber 26a to the gas port i5. The numeral i6 modifications will occur to‘those skilled in the ‘ ‘indicates a pair‘ of air uptakes leading to the air ' art. It is intended to cover all such modi?cations that fall within the scope of the appended claims. port i1. Said air port i'i servesto conduct the products of combustion from the furnace to the regenerator l3 when the furnace is reversed. Gas containing hydrocarbons is conducted to the’ ' cracking chamber 26a through the pipe 2|. If 15 preferred, the gas containing hydrocarbons may be introduced through the pipe 2ia into the pipe 26, whereby to produce aspiration of'air by the gas issuing from the pipe 2la. The thermocouple 20 23 is connected in the pipe 21. Said thermo couple controls the regulator 24, which in turn controls the operating cylinder 25. Said oper ating cylinder 25 controls the position of the valve 28 located in the pipe 26 leading to the cracking chamber 26a. Said valve 28 is adapted to close 25 completely communication between the cracking chamber 26 and the air regenerator l3. It will be understood, of course, that any other control vmeans for the valve 28 may be utilized if pre 30 ferred, instead of the thermostatic control illus trated. . ' J The mode of operation of the structure shown 10: What is claimed‘ is' _ 1. The method of operating a reversing 'regen~ erative furnace fired ‘with a fuel containing hydro- ‘ carbons which, consists in admitting a regulated quantity of regenerated air into contact with said 15 fuel prior to its introduction to the furnace, rais ing the temperature of the resulting mixture by partial combustion to crack part of the hydrocar- , bons contained in said fuel and thereafter intro ducing the resulting mixture to the furnace, ad 20 mitting regenerated air to ‘said furnace in con tact with said gaseous'mixture, and, when the fur- . nace is reversed, stopping the flow of products of combustion along the path of. said incoming gas eous mixture._ ‘ ' ' - ‘ 2. The method of operating a reversingregener ative furnace using a gaseous fuel which contains ~25 hydrocarbons and a gaseous fuel which does not contain hydrocarbons which consists in regener ating the fuel. which does not contain hydrocar 30 icons and admitting it to the’ furnace, admitting in Figure 4 is to permit a regulated amount of a regulated quantity of air to the gaseous fuel air to rise in the cracking chamber 26a. and to which contains hydrocarbons, bringing said last unite with the gas from the pipev 2| or the pipe mentioned fuel to a cracking temperature and 35 2 I a,- the combustion within said cracking chamber admitting itlto contact with said gaseous fuel raising the temperature of ‘the gas to the cracking which does not contain hydrocarbons, and burn- \ 35‘ point. On reversal of the furnace, the valve 28 ing saidtwo fuels in said furnace. may be either open or closed, since there is but ‘a 3. The method of operating a reversing regener single regenerator at each end of the‘furnace and ‘ ative furnace using a gaseous fuel which contains , 40 the use of the pipe 26 and the ‘cracking chamber ‘hydrocarbons and a gaseous‘fuel which does not 40 26a as a downtake is optional. However, imporr contain hydrocarbons which consists in regener- . tant results are accomplished by closing the valve ating the fuel which does not contain hydro- ‘ 28 when products of combustion are going into carbons and admitting it to the furnace, admite the regenerator 2. The volume of the fuel gas 45 entering the furnace is small and the area of the port i5 may be very small and still afford suffi cient area for passage of gas into the furnace. The volume of air in relation to that of gas is so large that there is an advantage in bringing the 50 gas into closercommunication with the air than ting 'a regulated‘ quantity of regenerated air to the gaseous fuel which contains hydrocarbons, 45. bringing said last mentioned‘ fuel to a cracking temperature and admitting it to contact with said gaseous fuel which does not contain hydro carbons, burning said two fuels in said furnace, _and,'when said furnace is reversed, stopping the 50 flow of products of combustion along the path of is possible in a single port. If the valve 28 be held closed during reversal, there will be no pas i said regenerated air. sage of gases, solid matter, or slag vapors into the v4. The method of operating a reversingregen port i5; This fact permits a port construction in erative furnace which consists in admitting inde* 55 which multiple exits for the gas passing to the pendently regulated quantities of air in two paths, furnace are possible. Such'a construction is illus ' admitting hydrocarbon gas into contact with the trated in Figures 5 arid 6, in which the gas port I! air in one of said pathsand cracking a portion of has disposed therein the multitubular insert 29, > by means of which it is possible to in?uence both 60 speed of entry of gas into'the furnace and the conformation of the surface along which mixture of air and gas takes place for combustion pur poses. ' v . Referring now to Figure 7, the air regenerator i2 has two uptakes I6 leading to the air port I'l similar to the construction shown in Figures 1 and 2, and has a central uptake 30 leading to the gas port I 5. Gas containing hydrocarbons is introduced through the pipe 3i into the gas 70 port l5. said gas by partial combustion thereof, allowing said paths to meet for combustion in the furnace, and on reversal of the furnace delivering products 60 of combustion for regenerating purposes through only that path .to which gas had riot been admit - In the construction illustrated in Figure '7, the ‘air which has passed up through the central up take 30 flows through the port i5 in a stream parallel to and surrounding the gas delivered by the pipe 3i. By this means cracking will occur ted. ' . , 5. In combination, a reversing » regenerative furnace having an air port and a gas'port, an air regenerator connected to-said air port for receiving products of combustion from1 said fur nace when said furnace is reversed, a cracking chamber having an outlet for delivering gas to said gas port, means for delivering hydrocarbon 70 gas to said cracking chamber, means connecting ‘the outlet end of said air regenerator with said cracking chamber whereby regenerative air may be mixed with said hydrocarbon gas in said cracking chamber to partially crack said gas by 75 2,128,724 cracking chamber, means for admitting hydro carbon gas to said cracking chamber, means for cracking chamber for automatically regulating admitting air from the outlet end of said air the ainount of regenerated air delivered from. regenerator to said cracking chamber whereby said air regenerator to said cracking chamber. a portion of the hydrocarbons in said gas may 6.,In combination, a reversing regenerative be cracked, means for delivering gas from said combustion in said cracking chamber, and means responsive to temperature conditions at said furnace having an air port and a gas port, an airL regeneratorconnected to said air port for receiving products of combustion from said fur ll) nace when said furnace is reversed, a cracking chamber having an outlet for delivering gas to said gas port, means for delivering hydrocarbon gas to said cracking chamber, means connecting the outlet end of said air regenerator with said ‘cracking chamber whereby regenerative air may cracking chamber and said air regenerator, said gas port including a multiple-aperture means for causing the ?ow of gas through said gas port in a plurality of streams. 10. In combination, a reversing regenerative furnace adapted to burn hydrocarbon gas and a gas which does not contain hydrocarbons, said be mixed with said hydrocarbon gas in said furnace having a. gas port, an air port, an air cracking chamber to partially crack said gas by combustion in said cracking chamber, and means responsive to conditions at said cracking cham ber for automatically regulating the amount of regenerated air delivered from said air regen regenerator connectedwith said air port and a erator to said cracking chamber. » 7. In combination, a reversing regenerative furnace having an air port and a gas port, an 25 air regenerator connected with said air port and a gas regenerator connected with said gas port, a cracking chamber, means for delivering hydro carbon gas;v to said cracking chamber, means connecting said air regenerator with said crack 30 ing chamber whereby a supply of regenerated air may be mixed with hydrocarbon gas in said cracking chamber to crack a portion of the hy g cracking chamber to said gas port, and a valve adapted to shut off communication between said drocarbons in said gas, means for delivering the , gas from said cracking chamber to said gas port, ' and means responsive to conditions in said crack gas regenerator connected with said gas port, means for delivering hydrocarbon gas, a crack— ing chamber for receiving said hydrocarbon gas, and means connecting said cracking chamber with said gas port, means connecting said air regenerator with said cracking chamber whereby regenerated air may be mixed with said hydro carbon gas in said cracking chamber to crack 25 a portion of the hydrocarbons in said cracking chamber by partial combustion, and a shut-off’ valve in said connecting means between said air regenerator and said cracking chamber. 11. In combination, a reversing regenerative furnace having an air port and a gas port, an air regenerator connected to said air port, said air regenerator also having a connection with said gas port, means for delivering hydrocarbon gas to said gas port,-and a shut-off valve for 35 ing chamber for regulating the amount of air delivered from said air regenerator to' said closing communication between said gas port and said air regenerator upon reversal of said fur cracking chamber. nace. _- \ 8. In combination, a reversing regenerative 12. In combination, a reversing regenerative furnace having an air port and a gas port, an furnace having an air port and a gas port, an air regenerator connected with said air port and ‘air regenerator connected to said air port, said a gas regenerator connected with said gas port, . a cracking chamber, means for delivering hydro carbon gas to said cracking chamber, means 45 connecting said air regenerator with said crack ing chamber whereby a supply of regenerated air may be mixed with hydrocarbon gas in said cracking chamber to crack a portion of the hydrocarbons in said gas, means for delivering‘ the gas from said cracking chamber to said gas port,'a'nd means responsive to conditions in said cracking chamber for regulating the amount of air delivered from said air regenerator to said cracking chamber, said last mentioned means being adapted to shut 06 communication from 5.5 said furnace through said cracking chamber to said air regenerator when said furnace is re versed. . 9. In combination, a reversing regenerative furnace having an air port and, a gas port, an air regenerator connected to said air port; a air regenerator also having a connection with said gas port, means for delivering hydrocarbon gas to said gas port, and a shut-off valve for closing communication between said gas port and said air regenerator 'upon reversal of said fur nace, said gas port having a multiple-aperture nozzle for causing gas to ?ow into said furnace in a plurality of streams. 13. In combination, a reversing regenerative 50 furnace having an air port and a gas port, an air regenerator connected to said air port, said air regenerator also having a connection with said gas port, said gas port including a passage way located within said furnace and adapted to , function as a cracking chamber, conduit means for delivering hydrocarbon gas to said gas port, and a shut oil’ valve for closing communication between said gas port and said air regenerator upon_reversal of said furnace. “ ARTHUR J. BOYNTON.