Coke quenching practice for one-spot cars

A process for quenching hot coke discharged from an oven of a battery of coke ovens into a one-spot car. The process utilizes a unique arrangement of two sets of narrow angle spray nozzles to quench the coke. In addition to quenching the coke, one set of spray nozzles initially knocks down the peak portion of the coke pile and distributes the coke so that the exposed surface of the coke is substantially level. The quench liquid discharged through the narrow angle spray nozzles contacts about 50% to about 70% of the substantially level, exposed surface of the hot coke. Sufficient openings are provided adjacent the bottom of the one-spot car to drain the quench liquid to prevent the buildup of quench liquid in the quench car.

BACKGROUND OF THE INVENTION 
The present invention relates to an improved process for quenching coke in 
an installation utilizing a one-spot quench car by providing for effective 
distribution of quench liquid. 
The recent introduction of a one-spot quench car has created some serious 
problems for the coke manufacturer in the quality of the coke produced. 
For example, hot coke which is deposited in a one-spot coke quench car 
forms a high conical pile of hot coke with the depth of bed of coke under 
the peak portion reaching as much as about eight feet. Difficulty is 
experienced in getting sufficient quench liquid to all areas of the uneven 
bed of coke and hot spots in the coke are evident when the quenched coke 
is dumped on the wharf. The hot spots require additional manual quenching 
to avoid damage to conveyor equipment. Furthermore, a uniform moisture 
content throughout the bed of coke is desirable but practically impossible 
of attainment when manual quenching is required. 
Many attempts have been made to apply quench liquid to a bed of hot coke in 
a manner that will "put out the fire" sufficiently to avoid hot spots 
while producing a quality coke having a relatively low and substantially 
uniform moisture content. For example, U.S. Pat. No. 3,806,425 to Eckholm 
et al discloses quenching coke with solid streams of quench liquid to 
drive the quench liquid to the bottom of the pile at spaced apart 
locations so that the quench liquid penetrates the depth of the bed prior 
to complete vaporization and percolates through the bed quenching coke as 
it goes. The quench liquid is drained out of the bottom to prevent an 
accumulation thereof to avoid flooding. 
U.S. Pat. No. 1,677,973 to Marquard attempted to control the over and 
under-quenching of coke by applying a deluge of water through relatively 
wide angle sprays in five second periods at a rate of 150-200 gals. per 
second. The water was then allowed to drain and the step repeated for as 
many sequences as necessary to adequately quench the coke. 
After considering these two extremes for controlling quenching of hot coke 
which utilizes a one-spot quench car in which coke is pushed from a coke 
oven into a quench car to form a peak portion, a process was discovered 
which applies the quench liquid in a manner and pattern that levels the 
hot coke and provides for a thorough and uniform quenching of the coke. 
SUMMARY OF THE INVENTION 
It is therefore an object of this invention to provide an improved process 
for quenching coke. 
It is a further object of this invention to provide a process for quenching 
coke in a one-spot quench car. 
It is an additional object of this invention to provide a process for 
quenching coke in a one-spot car to produce quality coke having 
substantially uniform moisture content. 
The present invention accomplishes these objects by providing a plurality 
of sets of narrow angle sprays, wherein each spray nozzle produces a full 
coverage spray pattern without substantial overlapping of the patterns or 
impact zones produced by the spray nozzles. One set of sprays is directed 
at the pile of coke pushed into the one-spot car from the coke oven in a 
pattern that knocks the peak portion of the pile of coke down to form a 
substantially level exposed surface of hot coke in the quench car. The 
continued application of quench liquid by the sets of narrow angle sprays 
on about 50% to about 70% of the substantially level exposed surface area 
of coke results in coverage which effectively quenches the hot coke. 
Openings in the quench car are strategically located to provide sufficient 
drainage of quench liquid from the quench car to prevent buildup of quench 
liquid in the bottom of the car. 
The following terms, as used herein, shall have the meanings hereinafter 
set forth: 
"One-spot quench car": a quench car which remains stationary during the 
time that coke is being pushed from a coke oven into the one-spot quench 
car. 
"Narrow angle spray": the spray produced by a nozzle designed to have an 
included angle of spray of about 15.degree. to about 25.degree.. 
"Oven side": the side of the quench car adjacent the coke side of a coke 
oven battery as shown in "The Making, Shaping and Treating of Steel," 
Ninth Edition, 1971, FIGS. 4-25, p. 135. 
"Wharf side": the side of the quench car from which the quenched coke is 
discharged onto a coke wharf. 
"Full cone spray nozzle": is a nozzle which produces a conically shaped 
spray pattern having a relatively uniform distribution of water throughout 
the entire volume, i.e. a full coverage spray pattern.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to the drawings and particularly to FIGS. 1 and 2, the coke 
quenching practice for one-spot quench cars will be described in detail. 
One-spot quench car 10 is seen located in a quenching station 11. The 
one-spot quench car 10 is moved to the quenching station 11 for quenching 
of the hot coke when the push is complete. Quench car 10 moves along 
tracks 12 which are located on the coke side of a battery of coke ovens 
and running parallel to the coke side bench to a quenching station 11 
where the hot coke is quenched. 
The profile of the coke pile after pushing into the quench car 10 appears 
approximately as line 18 on FIGS. 2 and 5. 
Quench car 10 comprises a high side 13 which is adjacent the wharf side 30 
of the tracks 12 and a low side 14 which is adjacent the oven side 31 of 
the tracks 12. As best seen in FIGS. 2, 5 and 6, sides 13 and 14 of quench 
car 10 are provided with grated drain openings 16 and 17 which extend 
substantially the full length of each side, adjacent the bottom. Gates 15 
are pivotably hung or hinged on side 13. The gates 15 are adapted to be 
held shut during the push cycle and are swung outwardly from the car by 
escaping steam and quench water during quenching. Grated opening 17 
adjacent the lower portion of side 14 of quench car 10 is covered by a 
heavy, e.g. 1/2" solid plate 22 spaced from side 14 and fixed thereto to 
allow continuous draining of quench liquid from quench car 10 at that 
point. The bottom 19 of quench car 10 is sloped at approximately 5.degree. 
towards the oven side of tracks 12 to expedite the drainage of quench 
liquid. Sloped grated plate 20 is located adjacent the inside of side 14 
extending longitudinally of the car and affixed thereto to allow the 
quench liquid to flow freely through the grating 20, opening 21 between 
the solid plate 22 and the grated opening 17. This arrangement prevents 
buildup of very fine particles of coke in the corner of quench car 10 at 
the junction of bottom 19 and side plate 14. Quench car 10 is further 
provided with tilting means (not shown) which allows the car to be tilted 
toward the wharf side 30 to discharge the quenched coke at the conclusion 
of the quench cycle. 
Quench headers 39 and 40 are mounted on wall 25 of quenching station 11 
adjacent the oven side of track 12. Upper head 40 and lower header 39 are 
supplied with quench liquid from conduit 38. Referring particularly to 
FIGS. 3 and 4, quench headers 39 and 40 are seen to comprise a plurality 
of spaced nozzles, the nozzles extending outwardly from the header and as 
seen in FIG. 2 at an angle to direct the flow of quench liquid in a 
desired trajectory. Upper header 40 comprises five nozzles nos. 41, 42, 
43, 44 and 45 and two blanked connections 53 and 54 for the attachment of 
additional nozzles if desired or necessary. Lower header 39 comprises 
seven nozzles, including five nozzles 47-51 inclusive and two nozzles 46 
and 52. Two of the nozzles 42 and 44 on the upper header 40 are set at an 
angle, as shown, to direct the quench liquid to the peak portion of pile 
18 along with nozzles 47, 48, 49, 50 and 51 to knock the peak portion down 
such that the coke subsides and thereby provides a substantially level, 
exposed surface of coke in the quench car. The nozzles have a narrow spray 
angle of approximately 20.degree. and are described as full cone sprays 
producing a full coverage spray pattern. 
The pattern of distribution of quench liquid on the surface of the pile of 
hot coke in the quench car 10 is seen in FIGS. 1 and 2. The nozzles 47, 
48, 49, 50 and 51 on lower header 39 and the two nozzles 42 and 44 on the 
upper header 40 are mounted above the surface of the coke in the quench 
car 10 and are angled so that the spray is directed at the peak portion of 
the coke pile on the oven side of the quench car while the three nozzles 
41, 43 and 45 on the upper header 40 are similarly located above the coke 
pile surface and angled to direct the spray of quench liquid therefrom at 
the hot coke surface at the wharf side of the quench car. Nozzles 46 and 
52 on lower header 39 are directed at the coke in the corners of the car 
on the oven side. 
The close grouping of the five nozzles 47-51 along with nozzles 42 and 44 
directed at the peak portion of the pile of hot coke results in the peak 
portion being knocked down and a substantially level exposed surface 18' 
formed. Continued flow of quench liquid onto the surface of the coke 
provides sufficient quenching of the entire bed of coke with the excess 
quench liquid flowing freely through grating drain openings 16 and 17 to 
prevent buildup of quench liquid in the bottom of the quench car. The 
impacting of the quench liquid on the coke surface, flow of liquid through 
the coke and the percolation of steam back up through the bed of coke all 
tend to cause the coke to flow as a fluid bed to the corners of the quench 
car, resulting in a bed of coke that is substantially uniform in depth. 
The pattern of distribution of quench liquid on the substantially level 
exposed surface of the coke bed avoids overlapping of the areas of contact 
or impact of the nozzle sprays which would cause nonuniform moisture 
content in those small areas of overlap which get double the amount of 
quench liquid. 
SPECIFIC EXAMPLE 
The coke quenching practice of the instant invention was used to quench 
approximately 11.5 tons of hot coke, from a 4 meter oven, contained in a 
deep bed in a one-spot quench car. The hot coke was contained in a 
one-spot quench car having a horizontal surface area of approximately 220 
sq ft (20'.times.11'). During the quench, the deep conical shaped coke 
pile, which was formed by pushing coke into the one-spot quench car, was 
generally levelled to a relatively uniform depth of approximately 4 to 
41/2 feet, which is approximately twice the depth obtained with 
conventional moving quench cars. This levelling is necessary to uniformly 
quench coke in the one-spot car. 
The quenching process utilized two 12-inch diameter spray headers which 
were located on a side wall of the quenching station, one above the other. 
The vertical distance between the two headers was three feet. There were 
seven spray nozzles on the lower header and five spray nozzles on the 
upper header. Spacing between nozzles varied from 15 inches to 45 inches. 
The full cone spray nozzles used to produce a full coverage spray pattern 
had a 20 degree included angle with a discharge opening of 2-5/16" 
diameter. Total water flow rate through the spray system was 5,000 gallons 
per minute with pressures of 71/2 to 81/2 psig at the headers. The water 
or quench liquid from the spray nozzles contacted about 60% of the exposed 
surface area of the coke in the quench car. Thus, the quench liquid was 
applied to the coke in the quench car at a rate of about 37 gpm/sq. ft. of 
surface area contacted by the sprays. At this rate of water application 
the 11.5 tons of coke was quenched in 105 seconds. If water had been 
supplied at a faster rate, the quench time would have been considerably 
reduced (6,800 gpm--75 seconds quench time). After quenching, it required 
only approximately 45 seconds to drain any unevaporated water from the 
coke box. The quench water was recirculated and normally had a temperature 
of .about.68.degree. C. 
It was discovered that a practical range of flow-rates was between 5000 gpm 
and 8000 gpm to provide an efficient quench time/drain time ratio. In the 
above specific example when 8000 gpm was used the quench liquid was 
applied to the coke in the quench car at a rate of about 59 gpm/sq. ft. of 
surface area contacted by the sprays. 
The quench liquid from a first set of spray nozzles, i.e. nozzles 42 and 44 
spaced 7'-6" apart on upper header 40 and nozzles 47-51 spaced 1'-101/2" 
apart on lower header 39, in a first pattern was applied to impact upon 
the peak portion of the coke in the car to cause the peak portion to 
subside and thereby provide a substantially level exposed surface of coke 
in the quench car. As mentioned hereinbefore the fluid nature of the coke 
under the influence of the impacting quench liquid, liquid flow through 
the coke and the percolating steam caused the peak portion of coke to flow 
into the corners of the car and assume a substantially level surface. The 
coke of the peak portion which flows into the corners is substantially 
quenched during movement to the corners. Thus direct application of quench 
liquid from the spray nozzles is not necessary. This accounts for the 
absence of a spray pattern in the corners of the car adjacent patterns 45 
and 41 of FIG. 1. 
Quench liquid from a second set of spray nozzles, i.e. nozzles 41, 43 and 
45 space 5'-0" apart on upper header 40, and nozzles 46 and 52 spaced 
3'-6" outwardly respectively from nozzles 47 and 51 on lower header 39 in 
a second pattern was applied to impact upon areas of the coke surface not 
covered by the first set of spray nozzles so that the sum of the area 
contacted by the first pattern and the area contacted by the second 
pattern equals about 50% to about 70% of the substantially level, exposed 
surface area of coke in the quench car. 
The force of water on the coke surface due to the momentum of the water 
coming from the 20.degree. full cone spray nozzles having 2-5/16" diameter 
openings at the rate of 5000 gpm results in a vertical component per 
nozzle of 47 lbs. and a horizontal component of 32.5 lbs. If the flow rate 
is raised to 8000 gpm the vertical force is 74.3 lbs. and the horizontal 
force acting on the pile of coke is 52.5 lbs. These forces of water on the 
coke surface are for one nozzle. The 20.degree. spray nozzle impacts on an 
area of about 4.8 ft.sup.2 so the force is spread over this 4.8 ft.sup.2 
area of coke. 
It will be clear to those skilled in the art that any pipe or spray could 
produce the same force as the 20.degree. nozzles, given the same flow 
rate, however the area of impact is variable. If the area of impact on the 
coke surface is too small the force would tend to drive the water through 
the coke, forming a hole therein. If the area of impact is too large the 
effect of the force of the water on the impact area of the coke would be 
to quench the surface of the coke but not move it, i.e. knock the peak 
portion of the coke pile down. 
Water was able to drain through grates on both the wharf side and oven side 
of the coke car and during the quench there was no substantial buildup of 
water in the coke car. The floor of the quench car was sloped 5 degrees 
towards the bench side to completely drain all water from the car prior to 
dumping coke on the wharf. The drainage grates through which the 
unevaporated water was allowed to drain from the quench car had an open 
area of about 4500 in.sup.2. Drainage times of from 45-70 seconds were 
attained with no hot coke remaining after quenching. 
In order to prevent excessive indrafting of air through the grates during 
the time when coke was being pushed from the oven into the one-spot quench 
car and while the quench car was under a slight suction from a fan or 
other gas mover which was capturing pushing emissions, all or part of the 
drainage grates at the bottom of this car were covered. While the coke was 
being quenched in the quench station these covers did not restrict the 
free flow of unevaporated quench water or steam from exiting the coke 
quench car. The above was accomplished by using solid metal plates which 
were hinged at the top and covered the grated drain opening on the outside 
of the quench car. These solid doors were made of light gauge steel and 
were held shut while the car was under vacuum during the pushing cycle and 
were pushed outward by escaping steam and quench water during quenching. 
ALTERNATE EMBODIMENT 
Drainage areas as large as 8,000 in..sup.2 (55.5 ft..sup.2) may be used 
with this quench system. A good range for the drainage area is between 
2,500 in..sup.2 (17.4 ft..sup.2) and 8,000 in..sup.2 (55.5 ft..sup.2). 
Using drain grates with such a large drainage area is advantageous for 
quick drainage of unevaporated water from the quench car after the 
application of quench water is stopped as well as for allowing steam 
pressure to be released freely during quenching and thereby preventing 
coke eruptions or degradation of coke into coke breeze during the 
quenching operation. As noted hereinabove, drainage times of 45-70 seconds 
are possible with no hot coke remaining after quenching. In one-spot 
quench systems which require a more water tight quench car, i.e., less 
open area on the drainage grates, in order to achieve effective quenching, 
the drain time after stoppage of quench water can be as high as three 
minutes. This long drain time is necessary to avoid dumping large 
quantities of water on the coke wharf when the coke is discharged from the 
quench car. This lengthens the overall time required for the quenching and 
draining operation which in turn lengthens the overall cycle time, i.e., 
quench time plus drain time, of the one-spot quench car operation to such 
an extent that lost coke production can result. Drainage grates for use 
with the sprays employed in this system are provided on both the wharf 
side and the battery side of the coke quench car. Having drainage grates 
on both sides of the quench car prevents any substantial buildup of water 
in the box during quenching. This buildup is avoided in order to reduce 
the time required for drainage of unevaporated water after application of 
quench water is stopped. Sloping the floor of the box slightly (5 degrees) 
downward toward either side facilitates the drainage of any water still 
lying on the bottom of the box after quenching is completed. 
Rates of quench water flow as supplied to the narrow 20.degree. angle full 
cone spray nozzles employed with this process are 100 gpm/ft.sup.2 of open 
drainage area. Higher rates of quench water flow of 200 gpm/ft.sup.2 of 
open drainage area would be advantageous in lowering the overall cycle 
time spent in the quench station. However, as the rate of quench water is 
increased for a constant drainage area, there reaches a point where the 
water begins to build up in the quench car during the quench. When this 
occurs eruptions of coke from the car take place and the time required for 
drainage will be increased to a greater extent than the decrease in quench 
time which normally follows with the use of higher water flow rates. This 
then increases the overall cycle time devoted to quenching and draining of 
the water from the coke. Drainage areas much greater than 8000 in..sup.2 
are not practical for a one-spot quench car because the quench car is 
under vacuum and any modification which increases the drainage openings 
would alter the suction rates. In addition, inflow of air through the 
openings creates a chimney effect resulting in higher heat causing warpage 
of the quench car parts. Water flow rates above 500 gpm/ft.sup.2 of the 
drainage opening should be avoided because of the inability of the 
drainage openings to carry the water away to prevent buildup of water in 
the bottom of the car. When the water flow rate is over 1000 gpm/ft.sup.2 
of drainage area, large eruptions of coke from the box occur creating a 
housecleaning problem in the quench station as well as degrading the coke 
and causing formation of additional coke breeze, all of which are not 
desirable from the standpoint of an efficient operation. Such high rates 
of water application with minimal drainage of the quench liquid from the 
quench car are employed with quench piping systems which rely more heavily 
on water buildup in the quench car in order to achieve effective 
quenching. 
Effective quenching of hot coke may be accomplished by using full cone 
spray nozzles which produce a full coverage spray pattern with an included 
angle of about 15 to about 25 degrees. Using such a narrow spray angle 
nozzle has two primary advantages over conventional full cone nozzles, 
which produce sprays having included angles of as much as .about.100 
degrees, when quenching coke in the one-spot quench cars: (1) they produce 
a larger impact force which causes the conical pile of coke to level out, 
and (2) they provide for a condition of mininum overlap of spray water 
from adjacent nozzles which reduces the variability in the moisture 
content of the coke and lowers the average moisture content of the coke. 
The narrow spray angles are necessary in quenching coke in the one-spot 
cars because these cars are only approximately 1/2 the length of 
conventional "moving" quench cars. Using conventional wide angle sprays 
with an equivalent flow rate of water for such a short quench car would 
result in over-quenched coke in large areas where the sprays overlap. 
Also, the conventional wide angle sprays are unacceptable for quenching 
the deep beds of coke inherent in the one-spot quench cars mainly because 
of the excessively long quench times which are required with such nozzles. 
When quenching of the hot coke must be accomplished by spraying from the 
side walls of the quench tower (as opposed to conventional overhead 
sprays) such as is required by one-spot quench cars which are enclosed at 
the top and as described in the specific example, these narrow angle 
nozzles have an advantage over open ended pipes in that a better 
trajectory of water is supplied with the nozzles thus allowing for better 
coverage of water on the bed of hot coke. The quench systems which employ 
open ended pipes are generally designed to operate at very low pressures 
so as to avoid any breakup of the water streams. These low pressures 
result in a poor trajectory of water which essentially provides for little 
or no water on the coke farthest away from the spray headers. This results 
in hot spots of incandescent coke in the coke bed after quenching and 
requires additional quenching. Using the narrow angle, about 15 degrees to 
about 25 degrees, spray nozzles, a much larger area of the coke is sprayed 
and there is no hot coke remaining after quenching. The arrangement of 
spray nozzles contacts a major portion of the exposed surface of coke in 
the quench car with quench liquid. Contacting 60% of the coke surface with 
quench liquid results in an effective quench. Another advantage of the 20 
degree nozzles over the open ended pipe system is that levelling of the 
conical shaped hot coke pile is done gently without causing large 
eruptions which result in coke being thrown from the coke receiving box. 
When these coke eruptions occur a "housecleaning" problem is created. When 
using the narrow angle spray nozzles to quench coke, no substantial 
submergence of coke occurs during the quenching cycle, provided of course 
that the quench car has properly designed drainage openings of adequate 
free area to drain off the unevaporated quench water. 
SUMMARY 
The primary aim of this process is to apply a forceful coarse spray of 
water capable of levelling the conical shaped pile of hot coke into a pile 
of uniform depth, with minimal overlap of adjacent sprays, thereby 
providing for uniform quenching. Drainage area should be sufficient so 
that coke is not submerged in quench water, and that the drainage time 
after quenching is not excessive. The quenching is accomplished in a 
relatively short time without causing large eruptions of the coke from the 
quench car. Average moisture content of the quenched coke is acceptable. 
It will be apparent to those skilled in the art that various modifications 
may be made without departing from the spirit of the invention or the 
scope of the appended claims. There are many forms of one-spot quench cars 
to which the invention described herein is applicable as, e.g., sloped 
bottom cars, open cars, covered cars, tiltable cars, etc.