Description: FORM 2

THE PATENTS ACT 1970
(39 OF 1970)
and
THE PATENTS RULES, 2003

COMPLETE SPECIFICATION
(See section 10 and rule 13)

TITLE OF THE INVENTION

“A 6.25m TALL STAMP CHARGE COKE OVEN BATTERY”

APPLICANTS

MECON LIMITED
(ISO 9001 Company)
(A GOVT. OF INDIA ENTERPRISE)
Of VIVEKANAND PATH, DORANDA,
RANCHI – 834 002, JHARKHAND, INDIA.

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 in general to Coke Oven Batteries for producing high quality coke to be fed into the Blast Furnace to maximize its effect on blast furnace operations and improve the hot metal quality, and in particular to an improved 6.25m tall Stamp Charge Coke Oven Battery of 43.67 m3 cake volume to make the coke-making cost efficient, user friendly as well as environment friendly. The battery produces high quality coke used for higher metal reduction and optimum permeability for the flow of gaseous and molten products in the blast furnace. The battery is designed to utilize Coal stamping method with many innovative features to produce coke for Blast Furnace to be used in the process of steel making.

BACKGROUND AND PRIOR ART

Coke is produced by high temperature carbonization of pulverized coking coal (-3 mm size). In this process, coal is heated in absence of air up to a temperature of 10000C - 11000C to form lumpy coke. Coke is the most important material that is fed into the blast furnace in terms of its effect on blast furnace operation and hot metal quality. The coke making process generates several by-products which may be solid, liquid, gaseous or plastic in nature. Many of these by-products are toxic and dangerous for the environment. They have to be handled with great care and control. A high quality coke should be able to support a smooth descent of the blast furnace burden with as little degradation as possible while providing the lowest amount of impurities, highest thermal energy, highest metal reduction and optimum permeability for the flow of gaseous and molten products.

Coke is produced in batteries, each of which has a plurality of slot type ovens for carbonization of coal. Coal (coming from the coal preparation plant and stored in coal tower) is charged to each oven sequentially and heated in the absence of air for a specific period of time (known as coking period) to drive out the volatile matters present within coal. When the gas evolution and subsequent coal carbonization is complete, coke is pushed out of the oven, quenched and cooled suitably through wet/dry method and finally sent to the blast furnace via coke handling plant. Evolved gases from the ovens are taken to by-product plant for recovery of various valuable chemicals like tar, ammonia, naphthalene, benzene, sulphur, toluene, xylene etc. The cleaned coke oven gas still has a high calorific value and is partially supplied back to the coke oven as a heating fuel.

Hence coke oven battery can be operated without any external source of fuel. Surplus coke oven gas is utilized in other units of the plant. However, provision is also generally kept for utilising blast furnace gas (BFG)/ Mixed gas (MG) as alternate fuel.

The cost of coal is about 70% of the cost of coke production and any decrease in cost of coke production without compromising the coke quality directly impacts the cost of hot metal production. It is evident that the availability of coking coal reserves in India is limited. As coking coals are becoming more expensive, with high volatility in price and depleting reserves, coke producers are looking for using the cheaper coals in the blend. Hence, various techniques to use low grade of coking coal and also small percentage of non-coking coal has been in exploration since a long time. Development of Stamp Charge Battery is one of the novel methods for the purpose.

There are primarily two methods for production of coke on the basis of charged coal in the slotted ovens:

1) Top Charge Coke Oven Battery, and
2) Stamp Charge Coke Oven Battery.

In the top charged system, the coke chambers are filled with the coal blend through gravity. Coal in the bunkers located on the charging car is poured into the coking chamber through charging holes located in the roof of the battery.

In Stamp Charge Coke Oven Battery, the coal cake is formed in the steel box of the stamping-charging-pushing car via a set of stampers and introduced into the coking chamber through a door opening on the pusher side of the battery.

Components of stamp charging system:

1. Coal Handling and Preparation:

 Coal storage: Raw coal is stored in silos
 Coal blending: Various types of coal are blended to achieve the desired properties of the coke.
 Coal crushing and Screening: The coal is crushed and screened to the required size.

2. Stamping station:

 Stamping Machine: This machine compacts the coal into a dense cake by applying mechanical pressure. The coal is usually moistened to facilitate compaction.
 Stamping Box: The compacted coal cake is formed in a mold like stamping box that matches the dimensions of the oven chamber.

3. Charging system:

 Charging Plates: The compacted coal cake is introduced into the oven chamber through the door opening by sliding it directly from the stamping box through Charging Plates.

4. Coke Oven Battery:

Coke Oven battery is mainly constructed with Silica, Fireclay & Insulation refractories.

 Oven Chambers: The battery consists of multiple narrow, tall oven chambers designed for carbonizing the coal cakes.
 Heating flues: Locate between the oven chambers, these flues provide the necessary heat for carbonization.
 Regenerators: These are placed below the Inclined Flue and help save energy by using the heat from hot waste gases to pre-heat the air and gas before they are burned. This makes the heating process more efficient and reduces fuel consumption.

5. Carbonization Process:

 Carbonization: The coal cake is heated to around 1000-11000C in the absence of the air, causing it to decompose and form coke.
 Coke pushing: After carbonization, the coke is pushed out of the oven using a Stamping-Charging Pushing/pusher machine.

6. Coke handling and Quenching:

 Coke Bucket: In case of Coke Dry Quenching (CDQ) coke is transferred to Coke Buckets.
 Coke Dry Quenching (CDQ): From Coke Bucket the hot coke is transferred into the CDQ Chamber for Cooling the coke by circulating Nitrogen gas.
 Quenching car: The coke is transferred to a quenching car, which moves it to the quenching tower for wet quenching.
 Quenching tower: The hot coke is cooled by spraying it with water and is spread over the Coke Wharf sloped benches for evaporation of excess moisture.
Finally, the cooled coke is transported to the user using conveyor belts from CDQ/Coke wharf.

7. By-product recovery:

 Gas collectors: During carbonization, volatile by products as foul Coke Oven Gas laden with tar and ammonia are collected in the common pipe duct and routed to the By-product facility for further treatment.

In Stamp Charge Battery, low coking coal can be blended by 5～25% more than that of Top Charge Coke Oven to produce
coke of same quality thus reducing coking cost and subsequently the cost of hot metal production. In Stamp Charge Coke Oven Battery, coke is produced by high temperature carbonization of coal cake having consistent Bulk Density (BD) of 1.1 with moisture content of 10-11%. In the process of carbonization, coal is heated in absence of air and up to an average temperature of 1100 0C to form lumpy coke. For that purpose, the heating flue temperature is to be kept at 1250 0C to 1350 0C.

Stamp Charging gives flexibility in coal selection and enhanced coke quality with improved efficiency. With the increased focus of the industry over sustainable development, the redesigning of the conventional designs is the need of the hour to optimize resource utilization and minimize carbon footprint of the industry.

The main goal in the industrial process of preparation of stamped coal charges is to obtain the appropriate density of the charge, ensuring its trouble-free loading into the coking chamber. This guarantees the proper productivity of the chamber and obtaining coke of uniform, assumed quality. The necessary condition for the use of the stamp charge method is the appropriate compactness and mechanical strength of the charge, preventing it from falling apart while filling the chamber. Damage to the coal cake during filling causes considerable operational and environmental difficulties and reduces the productivity of the coking chamber. The weight of damaged coal cake usually ranges from several dozen kilograms to several tons. The stamped coal cake should withstand the loads resulting from its own weight; therefore, its maximum height is closely related to its mechanical strength. This is particularly important in the case of batteries with large-capacity chambers, due to the greater height of the compacted charge and thus its greater weight. All existing Stamp Charge Coke Oven Batteries having various operational constraints in terms of productivity and maintenance. For example, (1) Uneven distribution of loading forces over brickwork and thereby reducing the life of brickwork. (2) Maximizes the chances of cross-leakage and in turn makes the battery inefficient. (3) Non flexibility of choosing the different Fuel gas simultaneously for operation. 4) wastage of fresh water that is used to gas sealing of Ascension pipe lid 5) High heat transfer at the bottom of the oven chamber resulting localized spots 6) Low heat transfer at the top of the oven chamber resulting in under carbonization of coal 7) Generation of NOx pollutants in waste gas.

Thus, there is a great need in the industry for a stamp charge coke oven battery that can produce coke in a more environment friendly, efficient and economical way. The present invention seeks to overcome not only the above, but also other drawbacks of the prior art. This will become clear from the description of the invention that follows.
OBJECTS OF THE INVENTION

The primary objective of the invention is to provide a stamp charge coke oven battery which is more cost effective, efficient and environment-friendly. Stamp Charging provides flexibility in coal selection and enhanced coke quality with improved efficiency and increases the average battery life.

Another object of the invention is to provide a 6.25m tall stamp charge coke oven battery of hot oven dimensions 17220X6250X500 with wet cake volume of 43.67 m3.

Another object of the invention is to provide an Ascension Pipe (AP) lid water sealing using a water tank arrangement having natural circulation that enables substantial water conservation.

Another object of the invention is to provide a coke oven battery in which the brickwork of heating walls is designed in such a manner that a direct path for gas leakage from heating walls to ovens through the brick joints is eliminated during the operation of battery.

Yet another object of the invention is to provide an anchorage system of robust design for better distribution of loading forces over brickwork and thereby enhancing the life of brickwork.

Another object of the invention is to provide modified Stretcher Brick Shapes of heating walls with twin holes to facilitate air injection at multiple levels for proper burning and heat distribution which eliminates hot spot formation and reduces NOx formation in the waste gas.

Another object of the invention is to provide a coke oven battery with robust regenerator design along with regenerator sliding joints which also prevents ingress of cold air inside regenerators and arrests any leakage of Mixed gas / waste gas.

How the foregoing objects are achieved will be clear from the following description. In this context it is clarified that the description provided is non-limiting and is only by way of explanation.

SUMMARY OF THE INVENTION

The present invention is equipped with many new novelties which are described in the document.

a) 6.25m Height Stamp Charge Battery with Wet Coal Cake Volume of 43.67 m3:

It is a 6.25m tall Stamp Charge Coke Oven Battery of oven dimensions (hot) 17220 X 6250 X 500 with wet coal cake volume of 43.67 m3.

b) Robust Design of Anchorage System:

Anchorage system of robust design is having higher section modulus Buckstays with twin spring loading arrangement along with surface contact of Flash Plate to brickwork instead of linear contact. This design feature has been considered for better distribution of loading forces over brickwork and thereby enhancing the life of brickwork.

c) New design for Brick arrangement of Heating Walls:

Brick arrangement in the heating walls has been designed in such a way that a direct path for gas leakage from heating walls to ovens through the brick joints is eliminated thus minimizes the chances of cross-leakage and in turn makes the battery more efficient.

d) Double Flue Arrangement for Multi Stage Heating:

The Stretcher Brick Shapes of heating walls have been modified and provided with twin holes to facilitate air injection at multiple levels for proper burning and heat distribution which eliminates hot spot formation and reduces NOx formation in the waste gas.

e) Design to eliminate Cross leakage in Regenerator Zone:

The regenerator bricks are designed in such a way to increase robustness thus minimizing the chances of cross leakages.

f) Automatic Operation of Gas Bleeders of Gas Collecting Mains (GCM) :
Designed arrangement for Automatic Operation of Gas Bleeders of Gas Collecting Mains (GCM) without using any Electro Mechanical or Hydraulic Equipment. This design feature has been considered for safe operation along with ease of maintenance point of view.

g) Ascension Pipe (AP) Lid Water Sealing by a Water Tank Arrangement:
The new design of the Ascension Pipe (AP) lid water sealing using a water tank arrangement having natural circulation that enables substantial water conservation of up to 97% compared to the conventional design of water sealing of AP Lid. It includes a re-engineered water sealing and distribution mechanism that retains the required water levels while minimizing the overflow.

h) Stainless Steel Sheet to prevent Leakages of Gases and to Reduce Heat Loss:
S.S. sheet is used in the oven roofing to prevent leakage of gases. S.S. sheet is also used at regenerator face wall to prevent ingress of cold air from atmosphere through face wall and also to prevent leakage of Mixed fuel gas and other waste gases.

i) Arrangement of Both Side Waste Gas Tunnel:
Waste Gas at both side is being provided for flexibility in operation and maintaining heating regime of P/s & C/s Ovens.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The nature and scope of the present invention will be better understood from the accompanying drawings, which are by way of illustration of a preferred embodiment and not by way of any sort of limitation. In the accompanying drawings:-

Figure 1 is the Anchorage system with twin spring loading arrangement.

Figure 2 shows the Flash plate with higher contact surface area.

Figure 3 shows Overflow seal in Automatic Hydraulic Seal.

Figure 4 shows Improved AP Lid and Water Tank arrangement.

Figure 5 shows Brickwork arrangement to minimize cross leakage.

Figure 6 shows Multi Stage Heating.

Figure 7 shows Flash Plate (Single Body Design).

Figure 8 shows Regenerator tongue groove arrangement.

DETAILED DESCRIPTION OF THE INVENTION

Having described the main features of the invention above, a more detailed and non-limiting description of a preferred embodiment will be given in the following paragraphs with reference to the accompanying drawings.

In all the figures, like reference numerals represent like features. Further, the shape, size and number of the devices shown are by way of example only and it is within the scope of the present invention to change their shape, size and number without departing from the basic principle of the invention.

Further, when in the following it is referred to “top”, “bottom”, “upward”, “downward”, “above” or “below”, “right hand side”, “left hand side” and similar terms, this is strictly referring to an orientation with reference to the apparatus, where the base of the apparatus is horizontal and is at the bottom portion of the figures. The number of components shown is exemplary and not restrictive and it is within the scope of the invention to vary the shape and size of the apparatus as well as the number of its components, without departing from the principle of the present invention.

All through the specification including the claims, the technical terms and abbreviations are to be interpreted in the broadest sense of the respective terms, and include all similar items in the field known by other terms, as may be clear to persons skilled in art. Restriction or limitation if any referred to in the specification, is solely by way of example and understanding the present invention.

At the outset we present below the crux of the main invention:

“It is a 6.25m tall Stamp Charge Coke Oven Battery of oven dimensions (hot) 17220 X 6250 X 500 with wet cake volume of 43.67 m3. The anchorage system is having higher section modulus Buckstays with twin spring loading arrangement along with surface contact of Flash Plate to brickwork instead of linear contact. This design feature has been considered for better distribution of loading forces over brickwork and thereby enhancing the life of brickwork. Brick arrangement in the heating walls has been designed in such a way that a direct path for gas leakage from heating walls to ovens through the brick joints is eliminated thus minimizes the chances of cross-leakage and in turn makes the battery more efficient. The Stretcher Brick Shapes of heating walls have been modified and provided with ports at different levels to facilitate air injection at multiple levels for proper burning and heat distribution which eliminates hot spot formation and reduces NOx formation in the waste gas. The regenerator bricks are designed in such a way to increase robustness thus minimizing the chances of cross leakages. Designed arrangement for Automatic Operation of Gas Bleeders of Gas Collecting Mains (GCM) without using any Electro Mechanical or Hydraulic Equipment and external energy source for actuation. This design feature has been considered for safe operation along with ease of maintenance point of view. The new design of the Ascension Pipe (AP) lid water sealing using a water tank arrangement having natural circulation that enables substantial water conservation of up to 97% compared to the conventional design of water sealing of AP Lid. It includes a re-engineered water sealing and distribution mechanism that retains the required water levels while minimizing the overflow. S.S. sheet is used in the oven roofing to prevent leakage of gases. S.S. sheet is also used at regenerator face wall to prevent ingress of cold air from atmosphere through face wall and also to prevent leakage of Mixed fuel gas and other waste gases. Waste Gas Tunnels at both side is being provided for flexibility in operation and maintaining heating regime of P/s & C/s Ovens.”
i. Oven characteristics / Dimensions

Description Features
Oven Dimensions (L x H x Avg. W (W P/S / W C/S) 17220 x 6250 x 500 (480/520) mm
Cake Size 16250/ 16100 x 6000 x 450 mm
Pusher side width of oven 480 mm
Coke side width of oven 520 mm
Oven taper 40 mm
Number of heating flue 34 Nos.
Gap of Cake on P/S from each side of Oven wall 15 mm
Gap of Cake on C/S from each side of Oven wall 35 mm
Oven Pitch 1500 mm
Cake Volume (Wet) 43.67 m3
Bulk Density (Wet) 1.1 t / m3

ii. Operational characteristics

Description Features
Wet Coal Charge per Oven 48.04 t
Gross Coke per Oven 33.59 t
Coking Time 23 hr
Heating mode envisaged CO / Mixed Gas

We now refer to the accompanying drawings.

A) ANCHORAGE SYSTEM

In the prior art, Buckstays are loaded with springs at two levels (at bottom and at top level) only. These were not effective in checking the torsional rotation of oven during pushing operation resulting in opening/cracking of mortar joints of refractory brickwork resulting in cross leakage between oven chamber and heating flues.

In the existing Stamp Charge Battery due to higher pushing force and due to linear contact of flash plate with the brick work, the chances of damaging of end bricks & brick joints are more due to loading of anchorage. The flash plates are also in multiple parts and with linear contact with refractory brickwork in the existing design.

Due to higher Swelling pressure ( approx.. 0.9 Kg/cm2) during coking period and more severe Pushing Wall pressure ( approx.. 0.2 Kg/cm2) in Stamp Charge Coke Oven Batteries, there are higher tensile stresses in the brickwork of Heating walls. To take care of these higher tensile stresses, there is requirement of Anchorage System which can impart more compression and also having more robust arrangement to avoid the deformation and damaging of brick works.

In view of the above, the following inventions are adopted in the present invented Stamp Charge Coke Oven Battery.

1) Buckstays are having higher web thickness with Twin Spring Loading Arrangement.

In the existing art, the Buckstays are having lower web thickness with single spring loading at the various levels from top to bottom.

In the present invention, the web thickness of the Buckstay is increased to withstand the higher loading on Flash Plates through twin springs at various levels and the higher pushing forces and swelling forces during pushing and coking operations. With arrangement of two springs, the compression forces are distributed uniformly on the flash plate (2) and anchoring of brick work is happened more effectively.

It gives better stability to the Anchorage system (Refer Fig.-1)

2) Contact area between Flash Plates and Brickwork is increased.

In the existing art, there is linear contact between flash plate & brick work. The generated compression forces due to loading of springs on Anchorage system is not effectively transmits to the brickwork area in the linear contact arrangement. To improve this and ensuring the robustness of the anchorage system, the linear contact of flash plate and brickwork in other designs has been modified to surface contact (3) as shown in fig-2. This optimizes the distribution of loading forces over the brickwork which further supplements the protection of brick joint failure. It also minimizes the detrimental impacts of hard pushing (hard pushing incidences may be higher in stamp charge batteries as compared to the top charged batteries as low quality coking coal will be used in stamp charge batteries in higher proportion) incidents during the battery operation. This improves the longevity of the battery with battery operating at higher efficiency for a longer duration of the battery life.

3) Flash Plates are designed in a single part in comparison to design adopted by other designers

In the existing art, the Flash plates of Stamp Charge Coke Oven Battery are in multiple parts or with linear contact with brickwork. Due to the multi part flash plate arrangement, the loading points in the flash plates from anchorage system is increased. The increase in loading points results in increase of number of springs and increase in installation cost and operational & maintenance frequency. Also, in the case of linear contact flash plate arrangement higher anchorage load may be detrimental for brickwork.

In the present invention, the Flash plate (3) is in a single piece with higher thickness to take higher compression load. With this arrangement, points of loading between Buckstays (1) and Flash Plates (2) are reduced. Due to this, less no. of springs are required keeping same load condition which results in lower cost and requires reduced number of spring loading points to be regulated aiding in better regulation of loads. (Refer fig-7)

B) IMPROVED REFRACTORY DESIGN TO MINIMIZE CROSS LEAKAGE IN HEATING WALLS

In the existing art, many of the brick joints are situated in the middle of the flues in the upper part. Over a long period of time, the brick joints may become weaker and leakage of gas from heating walls to ovens occur. This cross leakage may lead to transfer of coal and raw Coke Oven gas between oven and heating wall leading to improper coking, localized burning and air pollution.

In the present invention, the bricks of the heating wall are designed with joints arranged in a way that minimizes the chances of cross-leakage. The brick joints (4) are embedded in the bricks with no joint exposed directly to the flues in heating walls. This ensures that cross leakage from the heating wall is nearly eliminated. To effectively minimize cross-leakage in a coke oven heating wall, the brick arrangement is designed with care. The aim is to prevent the cross-leakage in between oven chamber and heating flues through the joints between the bricks, which could compromise both efficiency and environmental pollution. (Refer Fig-5)

The detailed breakdown of the design strategy for achieving this are given below:

1) Brick Joint Arrangement (4)

• No Exposed Joints: The most important principle in minimizing cross-leakage is ensuring that no joint is exposed directly to the heating wall. This means the joints between the bricks should be embedded in such a way that they are shielded from direct connection with the flue chambers in heating wall.
o This has been achieved by carefully designing the orientation of the bricks and ensuring that the joints are aligned in a manner that prevents cross leakage between oven part and heating wall.

2) Overlapping Brick Joints

o Offsetting Joints: The arrangement of bricks follows a staggered or overlapping pattern. By offsetting the joints from one layer of bricks to the next, prevention of a direct path for Raw Coke Oven gas to travel through the joints to heating wall is eliminated, which helps in sealing the structure better.
o The offset pattern reduces the likelihood of cross-leakage by ensuring that any potential gaps in one joint do not align with gaps in the layer above or below.

3) Robust Interlocking, Axial & Transverse Tongue & Groove, in Headers & Stretchers

o In prior art, there were limited tongue & Groove arrangements in the headers and stretchers section of heating walls. In the present invention, these bricks are provided with axial and circumferential tongue & Groove arrangement for robust load bearing arrangement.

C) DOUBLE FLUE ARRANGEMENT FOR STAGE HEATING

In the prior art, the burning of fuel gases occurs at bottom of the heating wall at port openings of air and fuel gas. The products of gases are withdrawn by twin flue arrangement and the waste gas transfers the heat to the ovens through Silica refractories travelling through the twin flues. This type of heat transfer arrangement has the following drawbacks:

1) High Heat transfer at the bottom of the oven chamber near burning zone resulting localized hot spots.
2) Low Heat Transfer at the top of the oven chamber resulting in under carbonization of coal in the top zone (green coke).
3) Generation of higher NOx pollutants in waste gas.

Although, above drawbacks are counter balanced in the case of top charged coal bulk density (BD) distribution, as it varies from bottom to top i.e., BD is higher at bottom and lower at the top. In the case of Stamp Charged Coal cake, BD is almost homogenous along the cake height, and hence even heat distribution in the oven is essentially required.

To overcome the above deficiency, in the present invention, the air for burning is fed at multi levels in the heating wall. It facilitates the uniform burning for the fuel gas along the height of heating wall. (Refer to Fig. 6)

The stage heating system in our Stamp Charge Coke Oven Technology offers several advantages that improve both efficiency and the overall quality of coke production. Here are some of the key benefits:

1. Uniform Heat Distribution: In a stage heating system, the heat is generated by burning of fuel gas at different heights in flues and transferred to heating wall from flues progressively in different stages, which allows for more uniform temperature distribution across the Coke Oven.

2. Increased Efficiency: By optimizing the heat flow and temperature profile throughout the heating process, stage heating systems can improve the overall thermal efficiency of the coke oven. This means effective utilization of energy required to achieve the desired coke quality, thereby reducing fuel consumption and operational costs.

3. Enhanced Coke Quality: The gradual and controlled heating process ensures uniform carbonization of coal cake and prevents over carbonization at the base and under carbonization (green coke) at the top. Hence, it results in enhanced coke quality with improved coke strength, suitable for blast furnace performance.

4. Reduced Environmental Impact: With more efficient heat usage and better control over the heating process, a stage heating system can lead to lower emissions and minimum energy wastage. This is an important advantage as the coke industry faces increasing pressure to meet environmental regulations and reduce its carbon footprint and NOx emissions.

5. Enhanced refractory Life and Battery Longevity: Smooth temperature gradient reduces spalling of Silica Refractories. Precise control on heating prevents localized hot spots. Thus, it prevents Refractory degradation resulting in enhanced Refractory life and thus battery longevity.

6. Better Control over Carbonization Process: The stage heating system offers more precise control over the temperature at each stage of the carbonization process, which can lead to more predictable and stable coke production. This also helps in achieving desired coke properties more consistently.
Overall, the multi stage heating system (6) plays a crucial role in enhancing the efficiency, quality and sustainability of coke production, making it a valuable advancement in modern coke oven technology.

D) IMPROVED REFRACTORY DESIGN TO MINIMIZE CROSS LEAKAGE IN REGENERATOR ZONE

o Regenerator is one of the most critical zones in a coke oven battery due to its specific role in recovering heat from waste gases and preheating combustion air and Mixed gas before they enter the combustion chamber. This process significantly enhances the thermal efficiency of the coke oven battery. However, the regenerator zone is also prone to cross leakage, which can adversely affect the battery's efficiency, coke quality, and refractory life.

o Three (03) numbers of parallel tongue-and-groove brick arrangements are provided between each course in the regenerator zone. This ensures a robust and stable regenerator structure and also improves gas-tightness. Further, the presence of sliding joints between the regenerator zone and bus flue zone helps to accommodate differential thermal expansion and thus minimizes the risk of cross leakage in Regenerator area during operation. (Refer to fig.8).

E) AUTOMATIC HYDRAULIC SEAL FOR BLEEDERS

The raw coke oven gas generated from ovens during coking period is collected in Gas Collecting Mains. For safe operation of Gas collecting Mains and to release the amount of pressure beyond the set value, the Gas Bleeders are provided which releases the excess gas and decrease the pressure in Gas collecting Mains to desired value.

In the existing art, the automatic operation of Gas Bleeders is actuated by either electrical, mechanical or any other suitable means.

In the present invention, the set value of gas pressure in the Gas Collecting Mains is maintained by creating an Automatic Hydraulic Seal in the Gas bleeders. For creating the hydraulic seal, the Flushing Liquor is used which is used in the Gas Collecting Mains for cooling the hot generated raw Coke Oven Gas. If the Coke Oven Gas pressure, increases from the set/operational value, the gas pressure breaks the hydraulic seal and gas is released from the Gas Collecting Mains. Thus, reducing the gas pressure in the gas collecting mains for safe operation. For the actuation of bleeders, no any electrical/ mechanical/hydraulic equipment is being used.

Fig. 3 shows the Automatic Hydraulic Seal for bleeders. Hydraulic seal is maintained by continuous flow of flushing liquor through a funnel (1’). Liquor gets collected in the bottom shell (2’) and overflows through outlet piping (3’) designed such that hydraulic seal of a certain height is maintained using weirs (5’) in the outflow path. The excess overflowing liquor after passing through overflow piping enters into the Gas Collecting Mains. To prevent the foul gas from Gas Collecting Mains to enter into the overflow system and leak through the chamber in overflow unit for placing weir, a U-type hydraulic seal of a predetermined height (4) is provided in the overflow path outside the Gas Collecting Mains. This makes it fail-proof from any kind of manufacturing defect or erection faults.

F) ASCENSION PIPE LID DESIGN FOR WATER CONSERVATION

In the existing art, the gas sealing of Ascension Pipe (A.P.) lid is done by flowing fresh water in a special arrangement in which water overflows around the contact surface of Ascension Pipe and Ascension lid. Continuous water is flowed through pipes in the AP Lid and the overflowing water is collected in a separate pipe. In this arrangement, a lot of fresh water is being used which afterwards is directed to drains.

To save the fresh water consumption, a novel arrangement has been done in our present invention. As shown in Fig. 4, the improved AP lid water sealing design comprises the following:
• A high-water retention chamber (water tank) designed to maintain a constant water level and caters the even level of AP lids in installation.
• A provision that avoids water ingress to oven even when maintaining high level of water sealing.
• The system maintains a stable water level in an open system architecture that strategically controls water movement and ensures uniform pressure distribution.
• Reduces the water consumption by maintaining a slightly lower water level in individual AP Lid that prevents the overflow of water by optimizing the water level of water tank.
The new AP lid design ensures that once the optimal water level is set in individual AP lids, it remains constant without the need for frequent refilling, regardless of operational pressure variation.
This design provides the following advantages:
• Reduces water consumption by up to 97% as instead of overflow of water from each AP lid in conventional design. Overflow is maintained only in water tanks, eliminating the need of overflow of water from each AP Lid.
• Environmentally sustainable and compliant with future regulatory standards.
• Reduction in energy usage associated with water pumping and waste water treatment.

G) USE OF STAINLESS STEEL (SS) SHEET

In the existing Stamp Charge Coke Oven Batteries, a significant amount of leakages of gas occurs from the oven top. Also due to suction generated in Regenerator zone, chances of cold air ingress increase in this zone over a significant period of time when the mortar joints in the area becomes weaker. To eliminate this problem, Stainless-Steel sheets are being used in different ways in the construction of Stamp Charge Coke Oven Battery in the present invention.
The use of Stainless Steel (SS) Sheet is defined below:

1) SS Sheet in Oven Roof Zone:

o Location: Stainless Sheet is placed between the insulation layers of brick works.

o Function:

 It prevents the leakage of raw coke oven gas (CO gas) from the oven through refractory oven roof into the surrounding environment, improving safety and reducing pollution. This function also contributes to energy conservation.
 The sliding joint arrangement between the silica and fireclay bricks ensures flexibility, allowing for differential thermal expansion without damaging the structure.

2) SS Sheet in Regenerator Face Wall:

o Location: Between mica and fireclay brickwork at the regenerator face wall.

o Function:
 Prevents the ingress of cold air into the regenerators, helping to maintain optimal temperatures for the regeneration process.
 This also serves to seal off any potential leakage of Mixed gas or other waste gases from regenerator, reducing harmful environmental impact and improving energy efficiency.
 The provision of SS Sheet here can be viewed as both a pollution control and energy-saving measure.

3) Material and Specification:

o The SS Sheet is of a predetermined thickness (~0.2 mm) and conforms to the standard IS 316L/AISI316, which indicates it is a high-quality, corrosion-resistant stainless-steel material. This ensures the sheet can withstand the harsh conditions in the Coke Oven and regenerator areas, where high temperatures and chemical exposures are common.

4) Pollution Control and Energy Efficiency:

o The overall design, with SS Sheet placed strategically between different brick layers, prevents gas leakage which ultimately helps in controlling pollution.

Key Benefits:

o Pollution Control: Prevents the leakage of harmful gases like raw coke oven gas and Mixed gas (if used as fuel), contributing to a cleaner environment.

In essence, these provisions, including the use of SS Sheet, are critical for the efficient and safe operation of a coke oven battery with environmental benefits.

H) Arrangement of Both Side Waste Gas Tunnel

Arrangement of both side waste gas tunnel imparts flexibility of maintaining temperature regime in the individual Coke side & Pusher side ovens as per operational requirement. In the present invention, there are 34 No. of flues. The 18 flues are connected to Pusher side waste gas tunnel and other 16 flues are connected to Coke side waste gas tunnel. This arrangement also helps in maintaining required waste gas draft in the Battery which is crucial in the case of using Mixed gas as fuel which is the preferred fuel in the Indian context for Coke Oven Battery operation.

The present invention has been described with reference to some drawings and a preferred embodiment purely for the sake of understanding and not by way of any limitation and the present invention includes all legitimate developments within the scope of what has been described herein before and claimed in the appended claims.
, Claims:We claim:

1. A 6.25m tall Stamp Charge Coke Oven Battery of 43.67 m3 cake volume provided with 34 nos. of flue and consisting of anchorage system over the flash plate, with Gas Collecting Main, ascension pipe (AP) lid water sealing using water tank arrangement, heating walls provided with twin holes to eliminate hot spot formation, S.S. sheet at oven roof and at regenerator face wall to prevent leakage, arrangement of both side waste gas tunnel for maintaining heating regime at Pusher and Coke side.

2. A 6.25m tall Stamp Charge Coke Oven Battery as claimed in claim 1 wherein sliding joint is provided between the silica and fireclay bricks in the Regenerator & oven roofing zone to ensure flexibility and thermal expansion.

3. A 6.25m tall Stamp Charge Coke Oven Battery as claimed in claim 1 wherein S.S. sheet is provided between mica and fireclay brickwork at the regenerator face wall to prevent ingress of cold air inside regenerators and seal off any potential leakage of waste gas.

4. A 6.25m tall Stamp Charge Coke Oven Battery as claimed in claim 1 wherein S.S. sheet is placed strategically between different brick layers in Oven roof zone to prevent gas leakage and reduce heat transfer.

5. A 6.25m tall Stamp Charge Coke Oven Battery as claimed in claim 1 wherein said stainless-steel sheet is 0.2 mm thick and conforms to IS 316L/AISI316.

6. A 6.25m tall Stamp Charge Coke Oven Battery as claimed in claim 1 wherein stage heating system is adopted to facilitate uniform burning for the fuel gas along the height of heating wall.

7. A 6.25m tall Stamp Charge Coke Oven Battery as claimed in claim 1 wherein 18 flues at pusher side and 16 flues at coke side are connected to waste gas tunnel that maintain efficient heating regime at both sides as per operational requirement.

8. A 6.25m tall Stamp Charge Coke Oven Battery as claimed in claim 1 wherein individual AP lid with optimal water level prevents water ingress to oven without need for continuous feeding.

9. A 6.25m tall Stamp Charge Coke Oven Battery as claimed in claim 1 wherein ‘U’ type Automatic Hydraulic Seal maintain pressure in the ‘U’ type gas collecting main by releasing the gas by breaking the seal when the gas pressure increases more than the predetermined value.

10. A 6.25m tall Stamp Charge Coke Oven Battery as claimed in claim 1 wherein the regenerator zone provided with special three (03) numbers of parallel tongue-and-groove brick arrangement to ensure proper locking of regenerator structure.

11. A 6.25m tall Stamp Charge Coke Oven Battery as claimed in claim 1 wherein the offset pattern of brick joints of heating wall reduces cross leakage.

Dated this 27th Day of June 2025.

(MONAJ SAHA)
To IN/PA - 1884
The Controller of Patents for S.S.DATTA &ASSOCIATES
The Patent Office, Kolkata Applicants' Agent