FORM 2
THE PATENT ACT 1970
(39 OF 1970)
&
The Patent Rules, 2003
COMPLETE SPECIFICATION
(See Section 10 and Rule 13)
1 TITLE OF THE INVENTION :
A NOZZLE ADAPTED FOR IMPROVED AMMONIA LIQUOR SPRAY FOR UNIFORM COOLING OF HOT RAW GASES IN A RECOVERY TYPE OF COKE OVEN BATTERY.
2 APPLICANT (S)
Name : STEEL AUTHORITY OF INDIA LIMITED.
Nationality : A Govt, of India Enterprise;
Address: Bhilai Steel Plant, Bhilai-490001, State of Chattisgarh,India.
3 PREAMBLE TO THE DESCRIPTION
COMPLETE
The following specification particularly describes the invention and the manner in which it is to be performed.

FIELD OF THE INVENTION
The present invention relates to a nozzle for improved ammonia liquor spray involving a selectively configured bent tube with selectively holes for optimized cooling of hot raw gases in a recovery type of coke oven battery. More particularly, said spray nozzle consisting of a single 120-deg round bend piece with external thread at one end to fit into the block, and internal thread at other end to fix the bottom plug which is installed within the gooseneck. The nozzle is having selectively disposed holes generating fine jets at different angles, creating a sort of mist when the jet struck the body favouring increased contact of liquor with the hot gases, as well as increased wetting of gooseneckcontinuous flushing of the tar in valve box thus enabling leakage free and jamming free operation of the system and uniform cooling of the hot gases eliminating undesired thermal stresses of the equipments and structures.
BACKGROUND OF THE INVENTION
In the coke making process, coal blend is charged into the slot ovens through the charging holes at the oven top. Inside the oven chamber (which is supported by heating walls at both sides to heat to the coal blend inside the oven chamber), the coal blend is carbonized to metallurgical coke by heating in the absence of air. After a predetermined time, coke is pushed out, cooled, sized & sent to blast furnaces. The coal blend which is charged in the ovens has volatile matter content of around 24% to 25% and the generation of raw coke oven gas is 310 NM3/T of blend charged. This gas mainly comprises of carbon mono-oxide, paraffin's, Aromatic compound, ammonia, hydrogen and viscous tarry materials and oils. The Gas withdrawal system of a Recovery type of Coke Oven Battery consists of Stands Pipes (SP), Goosenecks (GN), Valve Boxes (VB), Gas collecting main (GCM) on each side of the battery, crossover main, foul gas main on pusher side and Ammonia liquor spray in the goosenecks. Each oven at the top is provided with 5 holes. The extreme 2 holes are used for gas withdrawal. The middle 3 holes are provided for charging the coal blend in to the oven and these holesrare sealed after the charging operation is over. Standpipes are M.S. pipes and refractory lined and these are erected on these holes. On the top of the stand pipe bend is provided for making a change of direction of gas. This bend is called gooseneck. At gooseneck, facility is provided for continuous spraying of flushing Ammonia liquor thereby bringing down the temperature of the raw gas from 800°C to around 80-90°C. This helps in reducing the volume & temperature of gas and thus facilitates in its handling. The valve box

is the link between the oven and the hydraulic main and is connected to GCM through a nipple. The function of this VB is to isolate ovens from HM during pushing to avoid gas emission and to connect ovens to GCM during the Coking process so that generated gas flows to GCM. Ammonia liquor which is available in the Bye-product is used for flushing due to its much higher latent heat of vaporization as a result quantity required for flushing is much lower compared to the technical water. As deliberated above, Ammonia liquor that is sprayed in the gooseneck serves some important purposes:
i) To ensure proper cooling of raw gases to reduce the volume.
ii) To keep the inside surface of gooseneck and valve box wet, so that while cooling of gases, the condensing tarry chemicals do not stick to it.
iii) To flush out the tarry products from gas withdrawal system.
The conventional ammonia liquor spray system uses a vortex type of nozzle of 8 mm to 14 mm size for ammonia liquor spray for cooling of gas. There have been problems associated with conventional nozzles with respect to the proper cooling of gas in some or other forms, and leakage of liquor from the system to the structural fabric of the gas off take system. The liquor triggers untimely failure due to corrosion of the metallic parts. Maintaining proper position of baffle plates in vortex type of nozzles is also very difficult.
Unwanted leakage of liquor from the gooseneck window in the conventional cooling system provided for cooling had been a great source of damage to the hydraulic main nipple and pipe. Ammonia liquor being highly corrosive in nature corrodes the metal over long period of battery operation. As a result, holes develop leading to raw gas leakages and burning which further deteriorates the condition and it ultimately curtails the battery life.
Thus the conventional ammonia liquor spray cooling system for hot gases in recovery type coke oven suffered from following deficiencies and limitations:
i) Increased thermal stresses leading to cracks and damages in gas off-take
equipment, and even the hydraulic main nipples over long periods, ii) Increased leakages of gases from the gas off-take system, leading to nonconformance to the pollution norms, iii) Increased jamming of goosenecks, valve boxes and hydraulic main nipples due to increased deposition of tar.

It is thus evident that the total health of oven top equipment relies on the efficient cooling of gas in the gooseneck. If the cooling is proper, the temperatures remain uniform and stable. There will be less thermal variations, minimal thermal stresses generated and thus an enhanced life of equipment.
There has been therefore a persistent need in the related art to developing an improved ammonia liquor spray cooling system for hot raw gases in recovery type coke oven involving a selectively configured nozzle which would favour increased contact of the hot gases with sprayed ammonia liquor so that uniform cooling of the hot gases can be effected to avoid unwanted thermal stresses. Also the proposed system would be able to avoid existing problems of leakage of corrosive liquor from the system and jamming of equipments ensuring longer trouble free operation.
OBJECTS OF THE INVENTION
The basic object of the present invention is thus directed to providing a nozzle adapted forimproved ammonia liquor spray for uniform cooling of hot raw gases in a recovery type of coke oven batteryfor optimized cooling of hot raw gases in a recovery type of coke oven battery.
A further object of the present invention is directed to providing a nozzle adapted forimproved ammonia liquor spray for uniform cooling of hot raw gases in a recovery type of coke oven battery which would ensure increased contact of hot gases with ammonia liquor so the more uniform cooling of gases can be achieved.
A still further object of the present invention directed to providing a nozzle adapted forimproved ammonia liquor spray for uniform cooling of hot raw gases in a recovery type of coke oven battery wherein an optimum discharge pressure at nozzles would be maintained to ensure proper spread of liquor in gooseneck in form of umbrella.
A still further object of the present invention is directed to providing a nozzle adapted for improved ammonia liquor spray for uniform cooling of hot raw gases in a recovery type of coke oven battery wherein sufficient volume of liquor i.e. flow of ammonia liquor would be used for spraying to ensure desired cooling of gases.

Yet another object of the present invention is directed to providing a nozzle adapted for improved ammonia liquor spray for uniform cooling of hot raw gases in a recovery type of coke oven battery wherein proper contact of liquor with hot raw gases ensured for cooling of cross-section of gases passing through the gooseneck.
A still further object of the present invention is directed to providing a nozzle adapted forimproved ammonia liquor spray for uniform cooling of hot raw gases in a recovery type of coke oven battery wherein the inner surface of gooseneck and valve box is kept wet to avoid deposition and further jamming due to sticky tar generated during cooling of gases.
A still further object of the present invention is directed to providing a nozzle adapted forimproved ammonia liquor spray for uniform cooling of hot raw gases in a recovery type of coke oven batterywherein uniform cooling of hot raw gases would ensure avoiding thermal stresses leading to cracks and damages in gas off-take equipment, and even the hydraulic main nipples over long periods.
A still further object of the present invention is directed to providing a nozzle adapted for improved ammonia liquor spray for uniform cooling of hot raw gases in a recovery type of coke oven batterywherein leakages of gases from the gas off-take system is eliminated to maintain conformance to the pollution norms.
A still further object of the present invention is directed to providing a nozzle adapted for improved ammonia liquor spray for uniform cooling of hot raw gases in a recovery type of coke oven batterywherein jamming of goosenecks, valve boxes and hydraulic main nipples due to increased deposition of tar can be avoided by continuous flushing with liquor.
A still further object of the present invention is directed to providing a nozzle adapted forimproved ammonia liquor spray for uniform cooling of hot raw gases in a recovery type of coke oven batterywherein life of gas handling structure and equipment is increased.
A still further object of the present invention is directed to providing a nozzle adapted forimproved ammonia liquor spray for uniform cooling of hot raw gases in a recovery type of coke oven battery whereinconsiderable manual labor for cleaning of gooseneck could be saved.

A still further object of the present invention is directed to providing a nozzle adapted forimproved ammonia liquor spray for uniform cooling of hot raw gases in a recovery type of coke oven battery wherein said nozzle can be fitted as a replacement to old nozzles without additional attachment and modification in the existing set-up as well as in new recovery type of coke oven battery incorporating the ammonia liquor spray cooling system.
SUMMARY OF THE INVENTION
The basic aspect of the present invention is thus directed to a nozzle adapted for improved ammonia liquor spray for uniform cooling of hot raw gases in a recovery type of coke oven battery, comprising
a tubular.bent main nozzle body having external thread at one end to fit into the nozzle block and internal thread at other end to fix the bottom plug;
a plurality of holes selectively disposed on said main nozzle body and said plug such as to favour optimum discharge pressure at nozzle to ensure proper spread of liquor in gooseneck in the form of umbrella.
A further aspect of the present invention is directed to said nozzlewhich comprises
an integrally formed tubular 120-deg round bend main nozzle body with external thread at one end to fit into the nozzle block, and internal thread at other end to fix the bottom plug installed inside gooseneck adapted for dispensing said ammonia liquor inside said gooseneck;
a plurality of holes selectively disposed on said nozzle with bottom plug adapted to generate fine jets at different angles to create a sort of mist when the jet struck the body to thereby favouring increased contact of liquor with the hot gases, as well as increased wetting of gooseneck and flushing the tar continuously to achieve desired uniform cooling of hot gases for jamming and leakage free operation of the system.

A still further aspect of the present invention is directed to said nozzle herein said plurality of holes are of 3mm size drilled holes in said nozzle having locations comprising 3 holes 120-deg apart relatively near the block and 3 holes 120-deg apart after the bend, and one hole at the middle of bottom plug.
Yet another aspect of the present invention is directed to said nozzle adapted to provide avolume flow rate of 1.8 to 2.2 m3/nr preferably 2.0 m3/hr and a pressure of 0.7 to 0.8 kg/cm2 and preferably 0.8 kg/cm2 flow of ammonia liquor which is maintained for proper contact of liquor with hot raw gases to ensure cooling of cross-section of gases passing through the gooseneck.
A further aspect of the present invention is directed to said nozzle wherein said hole at center of bottom plug forms jet that is pointed towards the shaft of valve box, thereby flushing the tar continuously.
i A still further aspect of the present invention is directed to saidnozzle wherein said nozzle enables substantial reduction in temperature variations at the gooseneck body surface1 at different locations of gooseneck thus reducing thermal stresses.
A still further aspect of the present invention is directed to saidnozzle which is leak proof blocking leakage from any of the gooseneck window, as a result of which the gooseneck, valve box and hydraulic main nipple all are maintained dry and problem of corroding of HM nipple, damaging of joints due to liquor and the permanent damage to the refractory of battery is avoided.
The objects and advantages of the present invention are described hereunder in greater details with reference to the following accompanying non limiting illustrative drawings.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1: is the photographic image showing the vortex type of nozzle used in the conventional ammonia liquor spray system for cooling of hot raw gases in coke oven.
Figure 2: is the photographic image of the side view of specially configured nozzle with selectively disposed holes thereon used in the improved ammonia liquor spray system according to the present invention.
Figure 3: is the schematic photographic image of another view of specially configured nozzle with selectively disposed holes thereon and showing the external thread at one end to fit into the block, and internal thread at other end to fix the bottom plug used in the improved ammonia liquor spray system according to the present invention.
Figure 4: is the schematic block diagram of the specially configured nozzle for the improved ammonia liquor spray system according to the present invention showing the position of various components and holes.
Figure 5: is the schematic diagram showing the construction of box cage type tool used for fitting and removal of the modified nozzle inside the goose neck.
Figure 6: is the schematic diagram of the gooseneck showing the location of points for checking uniform distribution of temperature after using the modified and improved nozzle according to the present invention.
Figure 7: is the graphical presentation showing the gooseneck temperature variation against coking period using the conventional nozzle.
Figure 8: is the'graphical presentation showing the gooseneck temperature variation against coking period using the modified nozzle according to the present invention.
Figure 9: is the graphical presentation showing the temperature variation in HM nipple against coking period using the conventional nozzle.

Figure 10: is the graphical presentation showing the temperature variation in HM nipple against coking period using the modified nozzle according to the present invention.
Figure 11: is the graphical presentation of the observed variation in temperature at various locations on gooseneck surface on P/S (pusher side)for conventional as well as modified nozzle.
Figure 12: is the graphical presentation of the observed variation in temperature at various locations on gooseneck surface on C/S(coke side)for conventional as well as modified nozzle.
DETAILED DESCRIPTION OF THE INVETION WITH REFRENCE TO THE ACCOMPANYING DRAWINGS
The present invention is directed to providing an improved ammonia liquor spray system involving a selectively configured nozzle adapted in a recovery type of coke oven battery to ensure uniform cooling adapted to ensure cooling of hot raw gases, uniformity of temperature distribution in gooseneck, reduced cracks and damages of equipment due to thermal stresses and stoppage of leakage from gooseneck window and associated corrosion of nipple and HM pipe.
Reference is first invited to the accompanying Figure 1 which is the photographic image showing the vortex type of nozzle used in the conventional ammonia liquor spray system for cooling of hot raw gases in coke oven.
The conventional ammonia liquor spray system uses vortex type of nozzle of 8 mm to 14 mm size for ammonia liquor spray for cooling of gas. There have been problems associated with conventional nozzles with respect to the proper cooling of gas in some or other forms, and leakage of liquor from the system to the structural fabric of the gas off take system. The liquor triggers untimely failure due to corrosion of the metallic parts. Maintaining proper position of baffle plates in vortex type of nozzles is also very difficult. Due to insufficient contact of ammonia liquor with hot gases and non uniform cooling, the convention system leads to problems and disadvantages like increased thermal stresses leading to cracks and damages in gas off-take equipment, and even the hydraulic main nipples over long periods, increased leakages of gases from the gas off-take system, leading to non-conformance to

the pollution norms, increased jamming of goosenecks, valve boxes and hydraulic main nipples due to increased deposition of tar etc.
It is thus the basic aspect of the present invention to providing an improved ammonia liquor spray system involving a selectively configured nozzle which would ensure increased contact of the hot gases and sprayed ammonia liquor and thereby ensure uniform cooling and avoid uneven temperature distribution of equipments and structures and resultant thermal stresses.
Accompanying Figure 2 is the photographic image of the side view of specially configured nozzle with selectively disposed holes thereon used in the improved ammonia liquor spray system according to the present invention. Accompanying Figure 3 is the schematic photographic image of another view of specially configured nozzle with selectively disposed holes thereon and showing the external thread at one end to fit into the block, and internal thread at other end to fix the bottom plug used in the improved ammonia liquor spray system according to the present invention. Accompanying Figure 4 is the schematic block diagram of the specially configured nozzle for the improved ammonia liquor spray system according to the present invention showing the position of various components and location of drilled holes.
It is clearly apparent from the Figures 2, 3, & 4 that in the improved ammonia liquor spray system according to the present invention, the specially configured nozzle consist of a single tubular 120-deg round bend piece with external thread at one end to fit into the block, and internal thread at other to fix the bottom plug. Seven holes of 3mm size were drilled, 3 holes at relatively 120-deg near the block and 3 holes 120-deg apart after the bend, and one hole at the middle of bottom plug. Finally, the nozzle is fixed to block and the flange assembly.The volume flow rate of 1.8 to 2.2 m3/nr preferably 2.0 m3/hr, and a pressure of 0.7 to 0.8 kg/cm2 and preferably 0.8kg/cm2 flow of ammonia liquor is maintained for proper contact of liquor with hot raw gases to ensure cooling of cross-section of gases passing through the gooseneck.
After fixing this nozzle to the goosenecks of running oven, the spray pattern was observed and thermal scanning was carried out. The small holes generated fine jets at different angles, and a sort of mist was created when the jet struck the body. This increased contact of liquor with the hot gases, as well as increased wetting of gooseneck. The hole at center of

bottom plug formed jet that was pointed towards the shaft of valve box, thereby flushing the tar continuously.
The modified nozzles can be fitted as a replacement to old nozzles without additional attachment and modification in the existing set-up as well as in new recovery type of coke oven battery incorporating the ammonia liquor spray cooling system
A box cage type of modified tool is developed and used to remove or fix the nozzles into the block, thus making it easier to maintain as compared to the conventional nozzles where complete block had to be removed to change or inspect the nozzle. Accompanying Figure 5 is the schematic diagram showing the construction of box cage type tool used for fitting and removal of the modified nozzle inside the goose neck.
Improved cooling of hot raw gases in the gooseneck was studied and observed from thermal scanning study of ovens with modified nozzles against the conventional nozzle spray system over variations in coking periods. The result of such study is presented graphically in the accompanying Figures 7-10.
The temperature distribution in gooseneck was also studied for uniformity and the corresponding location of points of temperature measurement isschematically illustrated in the accompanying Figure 6.
Accompanying Figure 7 is the graphical presentation showing the gooseneck temperature variation against coking period using the conventional nozzle. Accompanying Figure 8 is the graphical presentation showing the gooseneck temperature variation against coking period using the modified nozzle according to the present invention. Accompanying Figure 9 is the graphical presentation showing the temperature variation in HM nipple against coking period using the conventional nozzle. Accompanying Figure 10 is the graphical presentation showing the temperature variation in HM nipple against coking period using the modified nozzle according to the present invention.
It is clearly apparent from the graphs in the above Figure 7-10, that the temperature variation in gooseneck as well as the HM nipple is more uniform in case of modified nozzle according to the present invention as compared to the conventional vortex type nozzle.

It was also observed that there was substantial reduction in temperature variations at the gooseneck body surface at different locations of gooseneck, with modified nozzles as against the conventional system. Thus, the modified nozzle improves the cooling efficiency inside the gooseneck. Accompanying Figure 11 is the graphical presentation of the observed variation in temperature at various locations on gooseneck surface on P/S for conventional as well as modified nozzle. Accompanying Figure 12 is the graphical presentation of the observed variation in temperature at various locations on gooseneck surface on C/S for conventional as well as modified nozzle.
It is further observed that by implementing the improved ammonia liquor spray system according to the present invention, there was no leakage of ammonia liquor from any of the gooseneck window, as a result of which the gooseneck, valve box and hydraulic main nipple all remained dry. The most prominent problem of liquor leaking out of gooseneck window and corroding of HM nipple, damaging of joints due to liquor and the permanent damage to the refractory of battery was almost nullified by incorporation of the modified nozzles in the claimed system.
Moreover, the shiny metallic surface appearing inside of gooseneck when inspected after a number of days of operation of the improved system justifies the fact that the gooseneck is wetted so well that there is almost zero deposition of tar in the gooseneck. By incorporation of modified nozzles it is required to inspect the gooseneck only rather than to clean it. A considerable manual labor of cleaning the gooseneck is thus saved.
It is thus possible by way of the present invention to providing an improved ammonia liquor spray system involving selectively configured spray nozzle adapted to ensure optimized cooling of hot raw gases, uniformity of temperature distribution in gooseneck, reduced cracks and damages of equipment due to thermal stresses and stoppage of leakage from gooseneck window and associated corrosion of nipple and HM pipe. The system also favour substantial saving in costs by avoiding replacement of valve boxes, welding of HM nipples, and by reducing labor costs engaged in routine cleaning activities. The system according to the present invention ensure increased life of gas handling structure and equipment, favouring long operating life free of interruptions due to ammonia liquor leakage and jamming by tar deposits within the equipments and thus enhancing productivity in recovery type coke oven battery.

We Claim:
1. A nozzle adapted for improved ammonia liquor spray for uniform cooling of hot raw
gases in a recovery type of coke oven battery, comprising
a tubular bent main nozzle body having external thread at one end to fit into the nozzle block and internal thread at other to fix the bottom plug;
a plurality of holes selectively disposed on said main nozzle body and said plug such as to favour optimum discharge pressure at nozzle to ensure proper spread of liquor in gooseneck in the form of umbrella.
2. A nozzle as claimed in claim 1 comprising
an integrally formed tubular 120-deg round bend main nozzle body with external thread at one end to fit into the nozzle block, and internal thread at other to fix the bottom plug installed inside gooseneck adapted for dispensing said ammonia liquor inside said gooseneck;
a plurality of holes selectively disposed on said nozzle with bottom plug adapted to generate fine jets at different angles to create a sort of mist when the jet struck the body to thereby favouring increased contact of liquor with the hot gases, as well as increased wetting of gooseneck and flushing the tar continuously to achieve desired uniform cooling of hot gases for jamming and leakage free operation of the system.
3. A nozzle as claimed in anyone of claims 1 or 2 wherein said plurality of holes are of 3mm size drilled holes in said nozzle having locations comprising 3 holes 120-deg apart relatively near the block and 3 holes 120-deg apart after the bend, and one hole at the middle of bottom plug.
4. A nozzle as claimed in anyone of claims 1 to 4 adapted to provide volume flow rate of 1.8 to 2.2 m3/nr preferably 2.0 m3/hr, and a pressure of 0.7 to 0.8 kg/cm2 and preferably 0.8 kg/cm2 flow of ammonia liquor which is maintained for proper contact of liquor with hot raw gases to ensure cooling of cross-section of gases passing through the gooseneck.

5. A nozzle as claimed in anyone of claims 1 to 4 wherein said hole at center of bottom plug forms jet that is pointed towards the shaft of valve box, thereby flushing the tar continuously.
6. A nozzle as claimed in anyone of claims 1 to 5 wherein said nozzle enable substantial reduction in temperature variations at the gooseneck body surface at different locations of gooseneck thus reducing thermal stresses.
7. A nozzle as claimed in anyone of claims 1 to 6 which is leak proof blocking leakage from any of the gooseneck window, as a result of which the gooseneck, valve box and hydraulic main nipple all are maintained dry and problem of corroding of HM nipple, damaging of joints due to liquor and the permanent damage to the refractory of battery is avoided.