US1933571A

US1933571A - Furnace and method of furnace operation

Info

Publication number: US1933571A
Application number: US489070A
Authority: US
Inventors: Trinks Willibald
Original assignee: Libbey Owens Ford Glass Co
Current assignee: Libbey Owens Ford Glass Co
Priority date: 1930-10-16
Filing date: 1930-10-16
Publication date: 1933-11-07
Anticipated expiration: 1950-11-07

Description

Nov. 7, 1933. w. TRINKS FURNACE AND METHOD OF FURNACE OPERATION Filed Oct. 16, 1950 3 Sheets-Sheet l MbQEW Q wmxwmmzmwww I H I W N l NVENTOR (1J1 lllba/d Tr/n/(s ATTORNEY Nov. 7, 1933. w. TRINKS 1,933,571

FURNACE AND METHOD OF FURNACE OPERATION Filed Oct. 16, 1930 3 Sheets-Sheet 2 INVENTOR ATTORNEY Nov. 7, 1933. w. TRINKS FURNACE AND METHOD OF FURNACE OPERATION 3 Sheets-Sheet 3 Filed Oct. 16 1930 INVENTOR (,d/H/balc/ Trm/Cs ATTO RN EY Patented Nov. 7, 1933 UNITED STATES PATENT OFFICE FURNACE AND DIETHOD F FURNACE OPERATION Application October 16, 1o

This invention relates to reversible regenerative furnaces and to a method of furnace operation.

While particularly applicable for use in the 5 making of glass, thefurnace and method of furnace operation providedby the present invention is not restricted to such use. On the contrary, this invention can be used equally Well in the heating or making of steel or in the performance of other heating operations. Consequently, while the invention will be herein de= scribed and illustrated as applied particularly to a glass melting furnace, yet it will be appreciated that this is only illustrative of one way in which it might be used.

In the making of glass, it is generally expo-- dient to employ a highly luminous and radiant flame. Such highly luminous flames are secured with comparative ease by either producer gas or natural gas. However, it is very difiicult to secure flame luminosity with by-product coke oven gas which is now being employed in an increasing number of glass melting furnaces. Heretofore, the use of by-product coke oven gas has always been attended with several disadvantages. By-product gas is often of comparatively low specific gravity and has very few heavy hydrocarbons. It consists of hydrogen and in some cases even contain 62% hydrogen, the rest consisting of light hydrocarbons which are mostly methane. On account of the high hydrogen content, the gas burns with an extremely hot atmosphere and produces scarcely any visible flame. The flame, if it may be called such, is almost transparent and cannot readily be seen by the furnace operator. Further, difflculty with coke oven gas lies in the fact that, due to its low specific gravity, it passes through the furnace with low velocity and tends to rise 0 to the roof, overheating the furnace and burning the roof while, at the same time, it fails to operate on the charge. Thus, the extremely thin but hot flame transmits heat but little by radiation and principally by convection. This causes hot spots where it touches the glass and the roof and leaves other places comparatively cool. The clear gases are still extremely hot upon leaving the furnace, that is to say, when entering the exhaust ports and regenerators, 3 which condition is of course undesirable. Attempts have been made to preheat the coke oven gas but they have always been unsuccessful because the hydrocarbons in the coke oven gas are cracked in the regenerators and form a carbonaceous crust on the regenerator walls clog- 1930. Serial No. 489,079 (Cl. 263-15) ging them up after a comparatively short time.

The present invention aims to overcome these objectionable features and likewise aims to render possible the practical and eflicient use of regenerated coke oven gas in a regenerative glass 0 melting furnace. Briefly stated, this is accomplished by mixing the coke oven gas with the products of combustion and then sending this mixture through the regenerator where it is preheated to cause the breaking up. or cracking 5 of the hydrocarbons of the coke oven gas to such an extent that, when subsequently mixed with the incoming air, a highly luminous flame is obtained. By mixing coke oven gas with the products of combustion, it is possible to obtain suf- 7 ficient velocity in the regenerator to prevent carbon deposits and encrustation of the checker bricks and checker chamber walls. Although some carbon may be deposited on the checker chambers, yet the small amount thus deposited is burned off by the puff of air which passes through the checkers upon reversal of the furnace.

An important object of the invention, therefore, is to provide a furnace construction particularly well adapted for the melting and production of glass and to a method of furnace operation whereby a relatively highly luminous radiant flame can be obtained with the use of coke oven gas. 5

A further object of the invention is the provi-' sion of a novel furnace construction including a system of conduits, fiues and pasages so arranged as to receive the products of combustion and the coke oven gas, efi'ect the intermingling thereof, and the delivery of the mixture to the furnace, means being provided for effecting the reversal of the furnace at desired intervals.

Other objects and advantages of the invention will become more apparent during the course of the following description when taken in connection with the accompanying drawings.

In the drawings forming a part of this appli= cation and wherein like numerals are employed to designate like parts throughout the same,

Fig. 1 is a fragmentary plan view, largely broken away. of a furnace constructed in accordance with the present invention,

Fig. 2 is a section taken substantially on line 2-2 of Fig. l,

Fig. 3 is a section taken substantially on line 3-3 of Fig. 1, and

Fig. 4 is a section taken substantially on line 4-4 of Fig. 1.

Referring now more particularly to the accompanying drawings, the melting end of a glass tank furnace is shown at 6, the glass batch being introduced thereinto at one end through a so- .called dog-house '7 and melted to produce a mass of molten glass 8. The molten glass produced is then caused to flow through the furnace toward the point of emergence where it may be worked into any desired kind of glassware.

Arranged along opposite sides of the melting end 6 of the furnace are the regenerative heating means 9 and 10, each including, as best shown in Fig. 2, a regenerator chamber divided by a vertical wall into gas and air chambers. The

numerals

11 and 12 designate the regenerators or checker chambers of the regenerative heating means 9 and respectively in which the air is preheated, while 13 and 14 represent the checker I chambers in which the mixture of coke oven gas and products of combustion is preheated. Arranged within the air and gas chambers at each side of the furnace are brick checker works 15 and 16 respectively, so constructed that the air and gas can flow in and around the same in a manner well knownin the art. The checker works 15 and 16 are spaced from the bottoms of their respective checker chambers to form therebeneath tunnels 1'7 and 18 respectively. Leading upwardly from the air and gas chambers are the uptakes or

passageways

19 and 20 respectively which merge at the end of the arch 21 in a port 22 at the side of the furnace.

Leading from the

checker chambers

11 and 12 of the regenerative heating means 9 and 10 respectively are conduits 23 and 24 respectively which communicate with one another at their outer ends and also with a flue 25 leading to a stack 26. The communication between the

conduits

23 and 24 and flue 25 is controlled by dampers 2'7 and 28 respectively which are adapted to be either wide open or dead shut.

The

conduits

23 and 24 open near their outer ends into chambers 29 and 30 respectively. (Fig. 3) which are located in back of but closely adjacent the

dampers

27 and 28. The chambers 29 and 30 are provided with

air intake openings

31 and 32, with the amount of air entering said openings being controlled by the butterfly valves 33 and 34, only one of which is adapted to be open, at one time. Each of the

intake openings

31 and 32 may be covered by a screen 35 to prevent the entrance of impurities and foreign matter into the chambers and conduits.

Leading from the checker chambers 13 and 14 of the regenerative heating means 9 and 10 respectively are the ducts 36 'and 3'7 respectively, said ducts extending substantially parallel with

conduits

23 and 24 and also communicating with the flue 25 running to stack 26. The flow from these ducts to the stack is controlled by slide valves 38 and 39 respectively.

By-product coke oven gas or a similar gas rich in hydrogen and poor in hydrocarbons is adapted to be delivered from any suitable source into the pipe 40 which branches into two passages 41 and 42, which communicate at their outer ends with the ducts 36 and 37 respectively, the flow of gas into passages 41 and 42 from pipe 40 being controlled by slide valves 43 and 44 respectively, adapted to be either wide open or dead shut. On the way to the furnace through passages 41 and 42, the flow of gas is also regulated by butterfly valves or similar regulating valves 45 and 46. For the purpose of correct mixing, that is to say, for mixing in correct proportions, the gas preferably flows through measuring flanges 4'7 and 48 before entering ducts 36 and 3'7, said measuring flanges producing a pressure drop, which latter is an indication of the quantity of gas flowing.

The products of combustion passing from the regenerator gas chambers 13 and 14 through ducts 36 and 37 can enter the stack 26 through flue 25 or they can enter a cooler 49 through flue 50. This cooler 49 is provided with a plurality of water pipes 51 which cool the products of combustion flowing therethrough practically to atmospheric temperature. In this cooling process, the moisture contained in the products of combustion from the combustion of hydrogen is almost entirely condensed and the condensate flows to the lower part of the cooler and is discharged through a water leg 52 which is preferably long enough to prevent the inrush of air through the bottom and which ends in a siphon or water seal 53. 1

The'producls of combustion in proper amounts are drawninto cooler 49 by means of a fan 54 driven from a variable speed motor 55. The cooled products of combustion are then discharged from the cooler 49 into a pipe 56 which is divided into two branches 5'7 and 58 which are arranged inwardly of passages 41 and 42, the branch pipe 57 communicating with duct 36 and branch pipe 58 communicating with duct 37. The flow from the branch pipes 57 and 58 into the ducts 36 and 37 is controlled'by valves 59 and .60 respeclively which are adapted to be either wide open or dead shut. On the way to the mixing chambers, the products of combustion passing through pipes 57 and 58 also pass through regulating valves 61 and 62 and also through measuring flanges 63 and 64. These measuring flanges will give indication of the rate of flow of the products of combustion for the purpose of allowing a correct volume proportioning between producis of combustion and by-product coke oven 'In the operation of the present invention and for the purpose of illustration, let us assume that the regenerative heating means 10 is in operation so that the flame will enter the furnace from this side, pass across the same, and exhaust through the regenerative heating means 9. The course taken by the air through the system is indicated by the arrows 64 in full lines, the course taken by the products of combustion being shown by the dot and dash arrows 65, and the course of the gaseous fuel by the arrows 66 in dotted lines. When thefurnace is being operated in this manner, the damper 27 and valves 38, 44 and are open while damper 28 and valves 39, 43 and 59 are closed. The air intake valve 34 is also open, whileair intake valve 33 is closed. Thus, the air entering through intake valve 34 into conduit 24 is adapted to flow therethrough to the regenerator chamber 12 where it rises, is prchea'ed. and moves to the furnace ports 22. Products of combustion coming down through regenerator chamber 11 pass through conduit 23 and stack flue 25 to stack 26. Although a part of these products of combustion may pass through flue 50 to the cooler, this is immaterial in the operation of the furnace. Products of combustion coming down through regenerator chamber 13 gas entering duct 37 are mixed as they enter the lating valve 62 and measuring flanges 64 into duct 3'7. By-product coke oven gas or a similar gas rich in hydrogen and poor in hydrocarbons is admit ed through pipe 40, passes through the wide open vah'e 44 in passage 42 and also through regulating valve 46 and measuring flanges 48 into duct 37 closely adjacent the point of entrance of the products of combustion thereinto from pipe The products of combustion and coke oven said duct and this mixture then passes through duct 37 into regenerator chamber 14 where it passes upwardly through the checker work to the furnace ports. As the products of combustion pass into the duct 37, the coke oven gas, being also introduced thereinto, will be carried along by the products of combustion and caused to be thoroughly intermingled or mixed therewith. As this mixture passes upwardly through the preheated checker work 16 in regenerator chamber 14, it will absorb heat therefrom, and this preheating of the mixture will cause a breaking up or cracking of the hydrocarbons of the coke oven gas. The preheated air mixing with the mixture of coke oven gas and the ports 22 of the furnace a highly luminous flame.

When it is desired to reverse the operation of is adapted to produce the furnace, the valves 27, 34, 38, 44 and are closed while

valves

28, 33, 39, 43 and 59 are opened. The air will then enter the conduit 23 through air intake valve 33 and pass therethrough to the regenerator chamber 11. Products of combustion coming down through regenerator chamber 12, will pass through conduit 24 and stack flue 25 to stack 26. Products of combustion coming down through regenerator chamber 14 will flow through duct 37 and be drawn by the fan 54 through flue 50 into cooler 49 and be delivered by the fan into pipe 57 through which it flows into duct 36. The by-product coke oven gas. entering through pipe 40 will pass through the passage 41 also into duct 36 and upon entering the said duct will mix and intermingle with the products of combustion and this mixture will then pass through duct 36 to regenerator chamber 13.

In operation, the fan 54 produces a vacuum which is more than suificient to furnish products of combustion for any proportion of mixture of coke oven gas and products of combustion. Valves 61 and 62 are relied upon to prevent an excessively large flow of products of combustion into the ducts 36 and 37 on the ingoing side of the furnace. It is evident that with every variation in the height of stack damper 67, there will be a slight tendency to vary the flow of products of combustion through pipes 57 and 58. If, however, the valves 61 and 62 are pretty well closed, such variation will be extremely small. Besides, the indication of the rate of how as given by the measuring flanges 63 and 64 will allow re-establishing' the proportionality if such proportionality should have been disturbed. Furthermore it is possible, by well known apparatus, to maintain automatically the pro- 'portionality of flow of products of combustion and of gas. Since such equipment is not a part products of combustion at of the present invention and is well known, it has not been shown.

A word need be said here why the products of combustion are cooled on their way to the re-,'

generator. On account of being so rich in hydrogen, coke oven gas burns mainly to nitrogen, water vapor, and a small amount of carbon dioxide. Both the carbon dioxide and the water vapor react with the carbon that is being liberated by the cracking in the regenerator, in the following manner: carbon dioxide reacts with carbon to form carbon monoxide, and water vapor reacts with carbon to form carbon monoxide and hydrogen. On account of the small amount of carbon dioxide which is present in the products of combustion of coke oven gas, the carbon dioxide-carbon reaction affects only a small part of the carbon. -.On the other hand, the water vapor reaction would cause the carbon which has been liberated by cracking to appear in the gases as carbon monoxide accompanied by hydrogen. Neither of these gases can produce a luminous flame, and it is therefore necessary to drop out most of the water vapor in the form of liquid moisture and to remove it through water leg 52.

Products of combustion coming from 'a glass furnace or even from a steel furnace always carry impurities and it is therefore to' be expected that cooler 49 will in due time be clogged up by deposits formed on the tubes. It will therefore be necessary to either provide cooler 49 in duplicate, allowing one to be used while the other is being cleaned, or else to provide automatic cleaning apparatus which scrapes the tubes while they are in use. Both methods are old and are therefore not shown in the drawings, neither are they claimed as part of this invention.

It is to be understood that the form of the invention herewith shown and described is to be taken as the preferred embodiment of the same, and that various changes in the shape, size and arrangement of parts may be resorted to without departing from the spirit of the invention or the scope of the subjoinedclaims.

I claim:

1. The method of furnace operation, comprising mixing gaseous fuel with products of combustion, cracking the gaseous fuel, and then feeding this mixture to the furnace.

2. The method of furnace operation, compris- .ing mixing coke oven gas with products of combustion, cracking the coke oven gas, and then feeding this mixture to the furnace.

3. The method of furnace operation, comprising taking products of combustion, cooling saidproducts of combustion to practically atmospheric temperature, mixing the cooled products of combustion with coke oven gas, and in preheating this mixture to crack the hydrocarbons of the coke oven gas.

4. The combination with a furnace including regenerative heating means, of means for receiv-- ing the products of combustion therefrom, means for mixing a gaseous fuel'with the products of combustion, and-means for passing this mixture through the regenerative heating means of the furnace to cause a cracking of the gaseous fuel.

5. The combination with a furnace including regenerative heating means, of means for receiving the products of combustion therefrom, means for mixing coke oven gas with the products of combustion, and means for passing this mixture through the regenerative heating means of the furnace to cause a cracking of the coke oven gas.

6. The combination with a furnace including regenerative heating means, of means for receiving the products of combustion therefrom, means for mixing coke oven gas with the products of combustion, means for cooling the products of combustion before being mixed with the coke oven gas, and means for passing the mixture of coke oven gas and products of combustion through the regenerative heating means of the furnace to cause the cracking of the coke oven gas. I

7. The method of furnace operation comprising taking products of combustion, cooling said products of combustion, mixing the cooled products of combustion with a gaseous fuel, cracking the gaseous fuel, and then feeding this mixture to the furnace.

8. The combination with a furnace, of means for receiving the products of combustion therefrom, means for mixing a gaseous fuel with the products of combustion, means for cracking the gaseous fuel, and means for feeding this mixture to the furnace.

9. The combination with a furnace, of means for receiving the products of combustion therefrom, means for mixing a gaseous fuel with the products of combustion, means for cooling the products of combustion before being mixed with the gaseous fuel, means for then cracking the gaseous fuel, and means for feeding this mixture to the furnace.

10. The combination with a furnace including regenerative heating means, of means for receiving the products of combustion therefrom, means for mixing gaseous fuel with the products of combustion, means for cooling the products of combustion before being mixed with the gaseous fuel, and means for passing the mixture of gaseous fuel and products of combustion through the regenerative heating means off the furnace to cause the cracking of the gaseous fuel.

WILLIBALD TRINKS.