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Aug. 16, 1938.
'
2,126,724
A. J. BOYNTON '
FURNACE AND THE OPERATION THEREOF
Filed Aug.‘ ‘1. 1936
2 Sheets-Sheet 1
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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.
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