US2554818A

US2554818A - Simultaneously firing a coke-oven battery with rich and lean fuel gases

Info

Publication number: US2554818A
Application number: US45636A
Authority: US
Inventors: Davis George Allen
Original assignee: Allied Chemical and Dye Corp
Current assignee: Allied Corp
Priority date: 1948-08-23
Filing date: 1948-08-23
Publication date: 1951-05-29
Anticipated expiration: 1968-05-29

Description

May 29, 1951 G. A. DAvls sTMuLTANEoUsLY FIRTNG A com ovEN BATTERY WITH RICH AND LEAN FUEL GASES Filed Aug. 23, 1948 UMO KCUNK NEDWWMKQ Q @MW @uw Y mw n Ta.U m m o wm. n im A d MDAOI W4@ 24mg Patented May 29, 1951 UNITED STATES PATENT OFFICE SIMULTANEOUSLY 'FIRING A COKE-OVEN BATTERY W'IT'H RECH AND LEAN FUEL GASES Application August 23, 1948, Serial No. 45,636 l l Claims.

This invention relates to the simultaneous .firing lof a coke oven battery with lean gas, such as blast furnace gas or producer gas, :and a rich gas, such as coke oven gas, the latter gas supplying not more than 25% of the heat required lto coke the charge.

Coke oven batteries are commonly designed to be fired by burning rich gas, such as coke oven gas fed directly to the heatinglues, or alternatively by burning lean gas, such as blast furnace gas, which is rst preheated by flow through the gas regenerators and the preheated lean gas then burned in the flues. In such batteries, known as combination oven batteries, the distribution main for the coke oven gas is designed to handle the relatively large volume of coke oven gas which must be burned When the battery is red with lcoke oven gas alone to supply the heat necessary to coke the charge. In the operation of such batteries it is sometimes desirable to fire the battery by supplying simultaneously blast furnace or other lean gas to the inflow gas regenerators and coke oven or other rich gas to the ues. For example, it may be desirable to burn a small amount of coke oven gas fed directly to the lues to insure satisfactory heating of the base of the charge in each coking chamber. When iiring With blast furnace gas alone, the base of the charge in each coking chamber may be undercoked due to the fact that an appreciable time interval elapses after the gas enters the flues and begins to burn for the maximum temperatures to develop. In some cases there may be an over-abundance of `coke oven gas, so that it is desirable to burn some of this coke oven gas to supply the heat necessary to coke the charge. In other cases the burning of the blast furnace gas of the type and in the volume available may be inadequate to supply the necessary heat to coke the charge at the desired rate. To provide the necessary heat for this purpose, coke oven gas may be fed directly to the flues and burned therein. When it is attempted to distribute a relatively small amount of coke oven gas through the coke oven gas distribution system, as distinguished from the normal flow employed when the charge is coked by burning coke oven gas alone, it is found that the pressure in the coke oven gas distribution system is so low that small variations inthe p-ressure Within the individual ilues caused by variations in draft to which the flue system is subjected, materially affects the distribution of the coke oven gas to the individual flues with consequent poor distribution of the coke oven gas to these flues.

It is an object of this invention to emciently and economically fire a combination coke oven battery with lean gas supplied directly to the inflow gas regenerators and rich gas supplied directly to the flues.

Another object of this invention is to provide a process for firing a coke oven battery in which rich gas is supplied in amount adequate to provide only a small proportion of the heat required to coke the charge, i. e., not exceeding 25% of this heat, to the rich gas distribution system of a capacity to supply al1 the coke oven or other rich gas required for heating the charge and at the same time obtain eflicient distribution of this rich gas throughout the heating iiues.

Still anotherobject is to provide an improved arrangement of rich and lean gas feed and -distribution lines and control mechanism therefore designed to supply any desired amount Vof coke oven gas to the coke oven gas distribution system, and notwithstanding the supply to the system of an amount .of coke oven gas ,far below that for which the system is designed when the battery is operated so that it vis fired by coke oven gas alone, uniform distribution of this smaller amount of coke oven gas throughout the hues is effected,

Other objects and advantages of this invention will be apparent from the following detailed description thereof.

In accordance with this invention, rich gas is supplied at a desired rate of flow tothe rich gas distribution system of a combination regenerative coke oven battery, the rate of flow being controlled to maintain it constant notwithstanding Variations in the rich gas supply, for example, Variations in the volume of rich gas Within the rich gas holder, lean gas is supplied to the lean gas distribution system to maintain a substantially constant pressure of lean gas within this system, a small amount of lean gas is Withdrawn from the main stream owing to the lean gas distribution system, this small amount mixed with the stream of rich gas fed at a controlled rate, and the pressure of the resultant mixture is regulated responsive to variations in pressure in the rich gas distribution system to supply to this system a mixture of lean and rich gas at a A substantially `constant desired pressure, desirably in excess of 5 mm. kof Water gauge, preferably at least l0 mm. of Water gauge, such that variations in draft within the ues do not appreciably alect the distribution of the mixed gas to the nues. Thus, the battery is fired by lean gas fed directly to the gas inflow regenerators Where the lean tions in draft to which the flues are subjected. l

When firing 'the `cattery with lean gas, it is important to supply at least 75% of the heat required to coke the charge by burning such lean gas, because, if a smaller amount of lean gas is fed through the inow gas regenerators, inefficient operation takes piace from the standpoint of preheating the lean gas and recovering the heat content of the outgoing products of combustion.

In the accompanying drawing, forming a part of this specification, the single figure illustrates a preferred arrangement of gas lines and controls therefore connecting the blast furnace gas holder nwith the blast furnace gas manifold and the coke oven gas holder with the coke oven gas manifold. The description which follows will be confined to the present illustrated embodiment of the invention. It will be understood, however, the scope of this invention is not confined to the embodiment herein described, but that other lean gas may be supplied to the lean gas distribution system instead of blast furnace gas, for example,

producer gas and other rich gas, such as water gas, natural gas, refinery gas, or other gas having a heating value greater than 150 B. t. u. per

standard cubic foot, may be supplied to the rich gas distribution system.

In the drawing IG indicates a blast furnace gas holder connected by a line Il' with the blast furnace gas manifold I2, which communicates with the gas inflow regenerators of a coke oven battery I 3. This battery may be any well known type of combination regenerative battery. As conventional the gas in its flow through these regenerators is preheated and the preheated gas fed to the flues where it is burned; air for supporting combustion is supplied to the flues by the air inflow regenerators.

Gas line Ii is provided with a usual shut-01T valve I4, flow meter I for indicating the rate of. flow of the gas therethrough and controlling Valve IE operated by a pressure controller I1 of any well known type, which is responsive to the pressure in the blast furnace gas manifold I2 and functions to position valve I5 to control the ow of blast furnace gas into manifold I2 such that a substantially constant pressure of gas is maintained within this manifold. A pressure recorder I8 of any conventional type may be associated with the pressure controller I 1 to provide a record of the pressure conditions within manifold I2.

A coke oven gas holder I9 has a line 2G leading therefrom. Valves 2I and 22 are disposed in line 2E) and a by-pass line 23 leads from line 2i) at a point intermediate valves 2I and 22, as shown in the drawing. Line 2i? leads into a heater 24, which may be heated by steam circulated on the outside of the pipes through which the coke oven gas hows for heating the coke oven gas to a temperature such that no condensation will occur in the subsequent flow of the gas to the flues.

A line provided with a valve 25, leads from heater 24 and is of a capacity to handle the flow of the entire amount of coke oven gas required to coke the charge.

An auxiliary line 21 of smaller capacity, say about 1A; of that of line 25 leads from line 25 and is provided with

valves

28 and 29 and a flow control valve 30 operated by a flow controller 3| of any conventional type, preferably the well known meter type which meters the gas and also can be adjusted to eiect operation of the controlling valve 30 to give any desired rate of ow of gas.

Associated with flow controller 3I is a pair of

orifices

32, 33, disposed in the auxiliary line 21 and the main gas line 25 respectively. Flow controller 3I has leading therefrom a pair of lines 34, line 34 is provided with two branch lines 36, 31 and line 35 with two branches 38 and 39. Branches 36, 38 communicate with auxiliary line 21 on opposite sides of the orice plate 32. Branches 31, 39 on the other hand communicate with main line 25 on opposite sides of the orifice plate 33 therein. Three-way valve 40 is positioned to place either branch 36 or 31 into communication with the line 34 leading to the flow controller 3|. In other words, in one position valve 40 shuts off the connection between branch 31 and line 34 and places the latter line in communication with branch 3B leading to one side of orifice plate 32 in line 21. In like manner three-way valve 4I may be positioned to place either branch 38 or 39 in communication with line 35 leading to the flow controller 3|.

A side stream line 42 provided with a valve 43 connects the blast furnace gas line II with line Line 42 communicates with line 25 at a point beyond the flow control valve 36 in the direction of flow of coke oven gas through line 25. A mixed gas line 44 leads from the point of jointure between line 42 and the gas line 25 to a coke oven gas manifold 45. Regulating valve 46 is disposed in mixed gas line 44 and is operated by a pressure controller 4,1 of any well known type responsive to the pressure within the coke oven gas manlfold Valve 43 is disposed in the mixed gas iine just before the point in this line where it communicates with the by-pass line 23. A pressure recorder 49 of any conventional type may be associated with the pressure controller 41 to provide a record of the pressure conditions within manifold 45. Valve 5G is positioned in the oy-pass line 23 and valve 5| in line 25. The function of bypass line 23 is to permit flow of coke oven gas through this line when it is desired, for any reason, to interrupt now through the main line 25, for example, for the purpose of cleaning and repairing any of the equipment associated with the line 25. When this by-pass line is used, valves 22 and 4t are closed and valve 5i! open. When by-pass line 23 is not in use, as customary, valve is closed and

valves

22 and 48 open. Bypass line 23 can, of course, be omitted, if desired.

In operation when the regenerative coke oven battery is fired with coke oven gas exclusively, valve i3 s closed, the blast furnace gas reversing valves (not shown) controlling flow of blast furnace gas to the gas inflow regenerators are all closed, being declutchecl from the reversing cables, and

valves

28 and 29 in auxiliary line 21 are closed. ValvnA i4 is maintained open so that the entire blast furnace gas system is under holder pressure, thus eliminating explosion hazards due to initration of air into the system. Valves 40 and 4i are positioned to place the opposite sides of orifice plate 33 in communication with flow controller 3i which operates only as a meter to show the volume of coke oven gas fed. The coke oven gas flows from the coke oven gas holder I9 through line 2HE, coke oven gas heater 24, line 25,

'valve 5I being open, line 4 4 into the coke oven gas ,manifold 45, valve 46 being operated bypr-essure :control 14.7i to maintain a substantially constant pressure of coke oven gas within manifold Y45. From this manifold the coke oven gas is distributed to the flu-es and burned; air for combustion is supplied from the air inflow regeneratcrs.

When it is desired to fire the coke oven battery with both lean gas and 'coke oven gas, the lean gas flows through line VIl into lblast furnace vgas Vmanifold :|2; the pressure controller l?! maintains a substantially constant pressure of blast furnace gas in manifold l2. At vleast 75% of the heat required to coke the charge is* supplied by the lblast furnace gas fed from manifold.` l2 -to the gas inflow regenerators from which the preheated ,blast furnace gas'ilows into the flues.

Coke "oven gas is .supplied simultaneously to line 20 from which Ait lhows into line 25; the remainder of the heat required to coke the charge, i. e., not vmore than 25% is supplied by the coke oven gas. Valve'! in line 25 is `closed and valves 4-0 and 4l positioned so that the flow controller 3l is in communication with the opposite sides of the orifice 32 in auxiliary line 2. Flow controller 3i is adjusted to give the desired rate of flow of coke oven `gas through lines 25 and 2l, this rate of flow being maintained substantially constant by the flow controller 315. 4That is to say, if Variations in the rate of supply of coke oven gas takes place due, for example,v to yariations in the volume of coke oven gas in holder I9, flow controller 3l -operates to `position valve 3Q to compensate for such variations -and maintain `a substantially constant vrate of flow through line .21 into line 44. The rate of-flowof coke oven gas for which controller 3l is set by the operator will he chosen Yto supply the heat., inaddition to that supplied by burningv the blast furnace gas, to efficiently coke the charge. This Will vary for each battery and will depend on many factors such as vthe amount of .blast furnace gas 'available, 'whether .the amount yresults-in satisfactory coking, including proper coking of the'base of the charge, the amount of coke oven gas available, 4

etc. For any given battery the optimum amount is readily determinable; in all cases when firing with both blast furnace andlean gas, the amount of coke oven gas employed should not exceed the amount which when burned supplies 25% of the i heat required to coke the charge.

A small amount of blast furnace gas flows from main line Il through the by-pass line 42, valve 43 being open for this purpose, and mixes with the coke oven gas flowing through line 44. The

pressure of the resultant gas mixture is controlled by pressure controller 4l which actuates Valve 46 so that the mixed gas comprising predominantly coke oven gas is supplied to the coke oven gas manifold 45 at a substantially constant pressure such as to eect uniform distribution of the gas to the burners in the flues notwithstanding variations in draft to which the ilues may be subjected. The amount of blast furnace gas thus supplied through bypass line 42 will vary in accordance with variations in pressure in the manifold 45.4 The amount of blast furnace gas thus supplied results in the supply of a mixture of coke oven gas and blast furnace gas at a substantially constant pressure to the manifold 45 which pressure may be as low as 5 mm. of water gauge, preferably about l0 mm. of water gauge and is adequate to cause satisfactory distribution of the gas from manifold 45 to the flues notwithstanding variations in draft to which the ilues are subjected. `The 'coke oven blast furnaceggas mixture 'is burned in the'flues along withtheA preheated blast furnace gas fed thereinto vfromthe inflow .gas regenerators. Air to .support combustion is applied to the ilues from `the air 'inflow regenerators. j'-` When the battery is fired with blast furnace gas exclusively, a small Aamount of blast furnace gas flows through valve 43 into the rich Agas ,manifold 45, valve 43 being opened for this vpur-- pose. The pressure of this gas within manifold '45 is maintained substantially constant at from 5 to 10 mm. water gauge by the pressure icontroller '41. Thus manifold 45 is constantly maintained under gas pressure eliminating explosion hazards due to infiltration of air thereinto.

It will be noted this invention provides ka combination coke oven battery which is efciently and leconomically fired by blast furnace gasor other lean gas supplied directly to the gas inflow regenerators and coke oven lor other riol1'gas supplied `directly to the flues, `in which .eillcient distribution of the coke oven gas to theflueais effected notwithstanding variations in Vdraft to which the flues are subjected and the fact that a relatively small amount of coke oven or other rich gas is supplied to the rich ,gas distribution system. Since certain changes in carrying-out'itheiabove process and in the coke oven battery set forth, which embody the invention, may be made Without 'departmg from its scope, it is intended 'that all kmatter contained in the above descriptionor 4shown in the 'accompanying drawing 1shall 'be interpreted `as illustrative and ynot -in a 'limi-ting sense.

What vis claimed is.: f 1, The process of ring a combination regen'- erative 'flued vcolte oven battery, which comprises flowing a stream of lea-n gas to the 'lean gas V'distribution system. thence through the regenerators where the lean gas is preheated and then into the nues; kcont-rolling the flow of a `stream of rich gas to the rich `gas distribution system communicating with the .ues of said coke Aoven battery so .as to .supply said rich gasto said rich gas distribution system at a predetermined rate to provide `not more than 25% of the heat required to coke the charge; withdrawing a portion of the lean gas stream flowing to the lean :gas distribution system and .mixing the portion thus withdrawn with the stream of rich gas; flowing the resultant mixture through a pressure regulating Zone; flowing the mixture from said regulating zone to the rich gas distributing system; controlling the flow of the mixture flowing through said regulating zone in accordance with a predeterminedpressure in said rich gas distri# bution system to supply said mixture at a sub stantially constant pressure substantially the same as said predetermined pressure in said rich gas distribution system and burning the lean gas and the mixture of rich and lean gases in the flues to supply the heat necessary to coke the charge.

2. The process of firing a combination regenerative ilued coke oven battery, which comprises flowing a stream of blast furnace gas to the blast furnace gas distribution system, thence throughy the regenerators where the blast furnace gas is preheated and then into the ilues; controlling the flow of a stream of coke oven gas to the cokel oven gas distribution system communicating with the flues of said coke oven battery so as to supply I said coke oven gas to said coke oven gas distribution system at a predetermined rate to provide not more than 25% of the heat required to coke the charge; withdrawing a portion of the blast furnace gas stream owing to the blast furnace gas distribution system and mixing the portion thus withdrawn with the stream of coke oven gasyflowing the resultant mixture through a pressure regulating zone; flowing the mixture from said regulating zone to the coke oven gas distribution system; controlling the flow of the mixture flowing through said regulating zone in laccordance With a predetermined pressure in said coke oven gas distribution system to supply said mixture at a substantially .constant pressure substantially the same as said predetermined pressure in said coke oven gas distribution system and burning the blast furnace gas and the mixture vof 'coke oven and blast furnace gases in the flues'to lsupply the heat necessary to coke the charge.

13. In a gas distribution system for ring a vcombination regenerative coke oven battery, in

combination, a lean gas line, a lean gas mani- A'fold` into which said lean gas line leads and communicating with the regenerators, a rich gas `line, a flow controller, a valve in said rich gas line operated by said flow controller for controlling the rate of llow of the rich gas therethrough, -a side stream line connecting said lean gas line with the rich gas line at a point in said rich gasline beyond said valve in the direction of `flow :of rich gas through said rich gas line, a mixed gas line through which flows the mixture of rich gas from said rich gas line and lean gas from said side stream line, a valve in said mixed gas line, a rich gas manifold into which said mixed gas line leads, and a pressure controller responsive to the pressure in said rich gas manifold for operating said valve in the mixed gas line to' contrcl'the flow of the mixture of rich gas and lean gas into the rich gas manifold so that the mixed gas is supplied to the rich gas manifold at a substantially constant pressure.

4. In a gas distribution system for ring a combination coke oven battery, in combination, a blast furnace gas holder, a blast furnace gas manifold, a blast furnace gas line connecting said holder with said manifold, a valve in said blast furnace gas line, a pressure controller responsive to the pressure in said blast furnace gas manifoldv for operating said valve to regulate the flow of blast furnace gas from said holder to said blast furnace gas manifold to maintain a substantially constant pressure of gas in said manifold, a coke oven gas holder, a coke oven gas manifold, a coke oven gas line leading from said coke oven gas holder, a valve in said coke oven gas line, a flow controller for operating said valve to cause the coke oven gas to flow through said coke oven gas line at a predetermined substantially constant rate of flow, a side stream line connecting said blast furnace gas line`with said coke oven gas line at a point in the flow through said coke oven gas line beyond the valve therein in the direction of flow therethrough, a mixed gas line leading from said point of jointure between said coke oven gas line and said side stream line to said coke oven gas manifold, a valve in said mixed gas line, and apressure controller responsive to the pressure in the coke oven gas manifold for operating said valve in the said mixed gas line to control the flow of the mixture of coke oven gas and blast furnace gas into the coke oven gas manifold so lthat the mixed gas is supplied to the Acoke oven gas manifold at a substantially vcon'- stant pressure.

GEORGE ALLEN DAVIS.

REFERENCES CITED UNITED STATES PATENTS y Date Number Name 1,398,055 Van Ackeren Nov. 22, 1921 1,597,365 Keigley Aug. 24, 1926 1,907,202 Ryan May 2, 1933 1,918,926 Otto July 18, 1933 1,921,145 Albright Aug. 8, 1933 1,968,367 Becker July 31, 1934 52,342,214 Otto Feb. 22, `1944 l. 2,342,426 Ransome Feb. 22, 1944 FOREIGN PATENTS Number Country Date 24,809 Australia of 1930 OTHER REFERENCES The Wilputte Coke Oven, published by the Wilputte Coke Oven Corp., 1944, pages 3 to 29. Copy in Div. 25'.