Changing oil tubes in a carbon black reactor

A steam line is connected to the oil lines supplying feed to a carbon black reactor and valves are provided in each of the steam and oil lines so that either or both steam and oil can be fed to the oil tube emitting feed into the reactor. To change an oil nozzle without interrupting production, oil flow to a single nozzle is cut off and steam flow is provided while the nozzle is removed from the reactor. Steam flow is again provided as the replacement nozzle is inserted into the reactor and when it is in place, steam is cut off and oil flow resumed.

BACKGROUND OF THE INVENTION 
In one aspect, the invention relates to carbon black production. In another 
aspect, the invention relates to an apparatus for producing carbon black. 
In yet another aspect, the invention relates to changing out feed tubes in 
a furnace. 
In the production of carbon black from a carbonaceous make oil, it is 
frequently desirable to change the nozzle through which the make oil is 
emitted into the reaction flow passage of the reactor. This is because the 
properties of the carbon black being produced can be varied by changing 
the nozzles. For example, in certain types of carbon black reactors, 
changing from a nozzle which emits a 20.degree. cone-shaped spray of 
feedstock to a nozzle which emits a 90.degree. cone spray dramatically 
changes the properties of the black produced. Also, nozzles sometimes 
become plugged or burn off in the reactor and must be removed for repair 
or replacement. Further, the pressure drop across a set of nozzles can be 
altered by changing out one of them. 
In many plant production systems, it could take operators an hour or more 
to change over the feedstock nozzles. During this time period, if the 
reactor were equipped with multiple nozzles, the carbon black being 
produced would not be on specification and thus could not be easily sold. 
Were the furnace to be shut down to replace the feedstock nozzle, the 
subsequent cooling of downstream processing equipment could make possible 
the formation of acidic condensate which can damage downstream equipment 
such as the filter bags. Also, downstream processes which rely upon the 
heat of the reactor such as the wet pellet dryer would encounter 
operational difficulties. 
In reactors where the oil nozzle is exposed, shutting down the oil flow to 
remove the nozzle allows excessive heating of the nozzle by the reactor 
combustion gases and sometimes the nozzle is thereby damaged. The oil 
nozzle can also be damaged when it is inserted into the reactor without 
flow of oil going through it due to overheating. 
A process to avoid overheating of the oil nozzles during changeout 
operations would be very desirable. A process which provides for changing 
out the oil nozzles without shutting down the reactor would be very 
desirable. A process which provides for rapid changeout of oil nozzles 
with minimal production of altered product would also be very desirable. 
OBJECTS OF THE INVENTION 
It is an object of this invention to provide an apparatus in which the oil 
nozzles can be changed without shutdown of operation. 
It is a further object of this invention to provide an apparatus in which 
nozzle changeout can be carried out with minimal production of 
off-specification product. 
It is yet another object of this invention to provide an apparatus in which 
the nozzles can be changed out with little danger of exposing the nozzle 
to excessively high temperatures. 
It is another object of this invention to provide a process in which the 
above objects are satisfied. 
STATEMENT OF THE INVENTION 
In one aspect, there is provided a first tubular member having first and 
second ends with a nozzle attached to the first end. An oil source and a 
cooling fluid source are operatively associated with the first tubular 
member by a means for simultaneously or alternatively connecting the oil 
source and the cooling fluid source to the second end of the tubular 
member. When the apparatus is deployed in a furnace such as a carbon black 
reactor for the injection of oil, it can be removed for changeout of the 
nozzle by initiating the flow of cooling fluid, terminating the flow of 
oil and pulling the oil tube from the furnace. Where three of more of the 
oil tubes are deployed in a single furnace the cessation of oil flow 
through one of them will not alter product properties to an unacceptable 
extent.

DETAILED DESCRIPTION OF THE INVENTION 
According to the invention, oil injectors 2 are provided for introducing a 
carbonaceous feedstock into a carbon black reactor 4. It is expected that 
equally good results will be obtained when the invention is applied to 
introduce most any combustible fluid into a furnace where temperatures are 
so high that the nozzle can be damaged by cessation of flow of combustible 
fluid through the nozzle. 
The injectors 2 are connected to a source 6 of combustible fluid. For 
carbon black production, the fluid generally comprises a highly aromatic 
high boiling oil such as a coal tar or refinery residuum. A source 8 of a 
cooling fluid, preferably a gas, to avoid the formation of deposits during 
evaporation is also connected to each injector 2. The source 8 most 
preferably comprises steam because it is readily available and cheap, 
although other light gas such as nitrogen or air could be used, although 
air flow could cause problems such as ignition of the combustible deposits 
in the oil tube if any were present. Preferably, a source of continuous 
cooling gas flow, such as air source 10 is also connected to the injector 
assembly 2 to provide a sheath around the oil tube and assist in avoiding 
overheating the nozzle. 
Each of the injectors 2 comprises a first tubular member 12, which can be 
an oil tube, having a first end 14 and a second end 16. A nozzle 18 is 
affixed to the first end 14 of the tubular member 12. Preferably, the 
nozzle 18 is of the monofluid type, although bifluid nozzles could also be 
utilized if desired. In the event that the invention were practiced with a 
bifluid nozzle, the nozzle would additionally be connected to the steam 
source or other atomizing gas by a separate line, not shown. The tubular 
member 12 is connected to the oil source 6 and the steam source 8 by a 
means 20 for the simultaneous or alternative connections of the tubular 
member 12 to the oil source 6 and the steam source 8. 
Preferably, the means 20 comprises a conduit 22 which forms a flow path 
between the oil source 6 and the nozzle 18 and a conduit 24 which forms a 
flow path between the steam or other cooling gas source 8 and the nozzle 
18. The conduit 22 preferably has a valve 26 positioned therein for 
control of the flow of oil therethrough. The conduit 24 preferably is 
provided with a valve 28 positioned therein to control the flow of steam 
therethrough. The valves 26 and 28 are preferably of the manual type. The 
conduits 22 and 24 are connected to the tubular member 12 so as to supply 
fluids to the nozzle 18. 
For rapid nozzle changeout, it is preferred that a flexible conduit 30 be 
positioned between the conduits 22 and 24 and the tubular member 12. In 
one embodiment, the conduits 22 and 24 are connected to the tubular member 
12 through a tee fitting 32. The conduit 22 is connected to the first 
branch of the tee fitting, the conduit 24 is connected to the second 
branch of the tee fitting 32, and the tubular member 12 is connected to 
the third branch of the tee fitting 32, preferably via the flexible hose 
30. 
In a preferred embodiment, a second tubular member 34 is positioned 
coaxially around a first tubular member 12 so that an annulus 36 is formed 
between the tubular member 12 and the tubular member 34. The air source 10 
is connected to the annulus 36 by a suitable conduit means 38. The tubular 
member 34 has a first end 40 positioned adjacent the nozzle 18 generally 
flush with the reactor wall and a second end 42 with a valve 44 mounted 
thereon. The valve 44 contains a gate or plug member which is movable from 
a first position in which the tubular member 34 is opened to receipt of 
the tubular member 12 to a second position in which the tubular member 34 
is closed to receipt of the tubular member 12. During nozzle changeout the 
gate or plug of the valve 44 is moved into the second position to close 
the flow passage and prevent the escape of reactor gases. A packing 46 is 
positioned adjacent the second end 16 of the tubular member to seal off 
the annulus 36 and the inside of the reactor from the outside when the 
valve 44 is in second position. A suitable packing can be formed with a 
gasket and the exterior of the tubular member 12 can be provided with an 
annular flange to engage a drawdown nut, not shown. 
Preferably, the reactor 4 is provided with three or more of the oil tubes 
or injectors 2 so that the cessation of oil flow through one of the 
injectors will not have an intolerably large influence on the properties 
of carbon black being produced, as long as changeout is reasonably fast. 
Preferably, six injectors are used, although four will provide good 
results and are cheaper than six. Four or more oil tubes should be used 
for good results. The reactor 4 is generally formed from a generally 
tubular mass of refractory 48 which defines a flow passage 50 having a 
longitudinal axis 52. The tubes 12 are preferably oriented so that their 
longitudinal axes are perpendicular to the axis 52 of the reaction flow 
passage 50. 
In operation, the oil tubes 12 are easily removed from the reactor when 
fouling or nozzle damage has occurred or where a change in the type of 
nozzle 18 being utilized is desired. To change out the oil tubes the valve 
28 is opened and the valve 26 is closed to initiate the flow of steam into 
the oil tube and terminate the flow of oil. The flow of steam will prevent 
excessive heating of the nozzle 18. The oil tube 12 can be pulled from the 
reactor after the loosening of the packing 46. As the first end of the 
tube 12 clears the plug or gate in the valve 44, the valve 44 is placed in 
the closed position to prevent escape of gases from the reaction flow 
passage 50. Steam flow can be terminated and withdrawal or removal of the 
oil tube from the reactor completed readily. 
Generally the flow of air annularly to the tube 12 is not interrupted 
because the flow of air assists in keeping the nozzle 18 cool and helps to 
prevent escape of reactor content through the valve 44. 
Once the nozzle 18 has cleared the reaction flow passage the flow of steam 
can be terminated or, in any event, terminated prior to changing of the 
nozzle 18 once the oil tube has been removed from the reactor. 
The procedure is simply reversed in order to install the oil tube. 
The invention is illustrated by the following example. 
EXAMPLE 
Four oil feed tubes, which are 2'6" lengths of 3/8" Sch 80 316 stainless 
steel, with appropriate pipe fittings attached to each end, were used to 
feed oil radially to a carbon black reactor. A convenient length of 316 
SS, Sch 80, 3/4" dia. single braid flexible oil hose was attached to a 
first end of each oil tube. Fulljet spray nozzles, 3/8 G 9.5, available 
from Spraying Systems Co., 3201 Randolph St., Bellwood, IL, were attached 
to the second end of three of the oil tubes, and a 1/8 G 5 fulljet spray 
nozzle, also from Spraying Systems Co., was attached to the second end of 
the fourth oil feed tube. 
The 3/8" oil tubes entered the reactor through an assembly comprising in 
seriatim; a 1" dia. Sch 80 pipe nipple PEXSE, 3" long welded to the 
reactor shell; a 1" dia full bore gate valve (VOGT 13111); a second 1" dia 
Sch 80 pipe nipple SEXSE, 3" long; a 1" dia WECO F18 200 pipe union; four 
3/16".times.3/16" asbestos packing rings; a 21/4" long packing gland, and 
a 13/4" long bushing. Thickness of the reactor wall, including shell, 
insulation, and refractory, was 151/4" at the point where the oil tubes 
were located. 
The oil was sprayed into a reaction zone which converged from a 21" dia to 
an 8" dia (throat) over a length of 181/2". Conduits for supplying oil, 
steam and purge air to the reactor were as shown in FIG. 1, except that 
the location of the oil injectors was rotated 45.degree. to provide 
sufficient ground clearance. 
With the reactor hot and operating, steam flow was initiated to one of the 
oil injectors and oil flow was terminated. With steam flow of 75 lb/hr at 
100 psig through the oil tube, the bushing holding the packing gland in 
place was loosened; the gate valve 44 in FIG. 1 was open, the oil tube was 
pulled from the reactor, and the gate valve was closed. After changing out 
the nozzle on the oil tube that was removed from the reactor, the 
procedure was reversed in order to reinstall the oil tube. Time required 
for changing out the spray nozzle was from 3 to 5 minutes. 
Reactor operating conditions and collected product specifications 
maintained while changing out the spray nozzle are shown in the table 
below: 
TABLE 
______________________________________ 
Total Air 248,499 SCFH 
Gas 16,067 SCFH 
Oil 555 GPH 
API.sup.1 -2.3 
BMCI.sup.2 127 
Air Temp 1220.degree. F. 
Oil Temp 259.degree. F. 
Tailpipe Temp 1435.degree. F. 
Oil Noz. Pres 139 psig 
Oil No.sup.2 Types 3 G 9.5 & 1 G 5 
I.sub.2.sup.3 (No) 84.7 
CTAB.sup.4 (m.sup.2 /g) 
90 
DBP.sup.5 (cc/100 g) 
111.1 
24M4.sup.6 (cc/100 g) 
89.7 
Tint.sup.7 (% 1RB#3) 
109.6 
Tint Residual.sup.8 4.0 
Grit.sup.9 (Wt. %) .0040 
Type N330 
______________________________________ 
.sup.1 API at 60.degree. F. 
.sup.2 Bureau of Mines Correlation Index 
.sup.3 ASTM 151076 
.sup.4 ASTM D3765-79 
.sup.5 ASTM D2414-76 
.sup.6 ASTM D3493-76 
.sup.7 ASTM D3265-76 
.sup.8 TR = T[56.0 + 1.057(CTAB) 0.002745(CTAB).sup.20.2596(24M4) 
0.201(N.sub.2 SACTAB) 
where TR = tint residual 
CTAB See footnote.sup.4 above 
N.sub.2 SA Nitrogen surface area per ASTM D3037-76 
24M4 See footnote.sup.6 above 
.sup.9 ASTM D1514-79