TITLE:
A process for the production of metallurgical coke and a device for the same.
FIELD OF THE INVENTION:
The present invention relates to a process for the production of metallurgical coke anda device for the same.
BACKGROUND OF THE INVENTION:
The coke making industry has seen some technological development over the last decade in conventional coke oven batteries. The non-recovery or heat recovery coke making technology has also make existence. At the same time, efforts have been made for reducing the emissions from batteries and coke production cost. A further increase in energy efficiency and lower the coke price for conventional coke batteries is expected.
In heat recovery or non-recovery stamp charge coke making technology making desired coke quality, the efficient thermal efficiency with optimal coke cost is a challenge for iron and steel industry. The factors for controlling the coke quality are the selection of coals, crushing fines, moisture content in the charged coal/coal blend, adopted coke charging methodologies, coking rate and thermal efficiency.

To find a possible solution for the selection of coals or designing of the coal blend with optimal cost in real time operation of heat recovery coke plant. This invention describes a method for operation of the non-recovery mini pilot oven which represents the all operating condition of the commercial coke plant. This is the small prototype non-recovery coke oven battery with a unique solution for selection of coals or designing of coal blend for the first time in coke making history. The proposed process or invention process is very cheap found to be the best solution techno-economically of designing of coal blend for coke making. This invention does not only help for reducing the coke cost but also optimize the coking rate or heating rate and thermal energy, and it also improves the coke quality.
OBJECTS OF THE INVENTION:
An object of the present invention is to propose a process for the production of metallurgical coke and a device for the same.
Another object of the present invention is to propose a mechanism of providing efficient thermal energy for faster coke rate.
Still another object of the present invention is to propose a process which reduces the coking time with a device coke quality.

Further, object of the present invention is to propose a coke making process at high temperature by carbonization of difficult length of coal blend in stamp charge condition.
Still further object of the present invention is to propose a device of the battery of ovens which can be used for coking, non-coking coals in environment-friendly condition.
BRIEF DESCRIPTION OF THE INVENTION:
According to this invention there is provided adevice for the production of metallurgical coke comprising a battery of ovens having a coking chamber with a temperature in the range of 950°C±50°C in oven crown and 900°C±50°C in the sole flue, a flue thermal is provided with charging stack when dry coke making air is admitted to the coking chamber in a controlled amount to burn the gaseous products distilled from coal to generate heat for complete carbonization and during coking process the produced hydrocarbon is combusted within the said oven which operates under negative pressure eliminating leakage from door and ports.
In accordance to this invention there is also provided a process for the production of metallurgical coke in a device, charging coal into an oven chamber to obtain devolatilized coal, subjecting the devolatilized coal to the step of carbonization, quenching the carbonized hot coke mass with water.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING:
FIG. 1showsa general layout of the non-recovery heat recovery ovens for producing
metallurgical coke
Fig. 2 shows the top view of ovens and position of downcomer pockets
Fig 3 shows the Schematic diagram for positions of down-comer pockets in conjugated
oven wall at oven sole
Fig 4 shows the schematic diagram of movement of flue gases in oven sole and flue
tunnel
Fig 5 shows the schematic diagram of the movement of heat and damper position in
flue tunnel
Fig 6 shows the schematic diagram of upper and lower door of the ovens
Fig 7 shows the schematic diagram of oven chimney
Fig 8 shows the typical temperature profile of oven crown and sole flue temperature during carbonization
Fig 9 shows thetypical temperature profile of oven sole flue temperature during carbonization
DETAILED DESCRIPTION OF THE INVENTION:
The present invention relates to developing a process for producing the desired quality of coke especially coke CSR in non-recovery / heat recovery stamp charge coke plant. More particularly it relates to a method for improving metallurgical coke strength by increasing the thermal efficiency of the non-recovery / heat recovery coke making process at high temperature by carbonization of different type of coal blend in stamp

charge condition adaptable to smooth operation of blast furnace and producing cheaper cost of hot metal.
In the non-recovery / heat recovery coke making process, air is admitted to the coking chamber in a controlled amount to burn therein the gaseous products distilled from coal to generate heat for complete carbonization or coking process. During coking process, the produced hydrocarbon is combusted within the oven because it operated under negative pressure. Therefore, it eliminates leakage from doors and ports; a problem that prevails in the by-product ovens. The operating costs of the proposed non-recovery mini pilot oven are very less, and they can run with cheaper coal or comparatively high volatile low-ranked coal since there is no significant impact of wall pressure during coal carbonization.
The principal object of the present invention is to provide a device of the battery of ovens which can be used for coking, non-coking and weakly caking coals for production of metallurgical coke in environment-friendly condition.
The pilot coke oven battery of the existent innovation is convenient (small quantity of coal charge) and first times build. The charging capacity of the invented method is ~100 kg in top charge condition, and ~130kg in stamp charge condition have been provided for the production of metallurgical coke.

Another object of the present invention is to provide energy efficient oven for faster coking.
Moreover, they were very less capital investment and generated enormous profit for designing the right coal blend based on the desired quality of coke for blast furnaces requirement. A significant new concept was introduced in the present invention and accordingly the construction of oven was done which made the oven much energy efficient and cost-effective.
According to the present invention, a process for the production of metallurgical coke using the device as described above which comprises charging of coal into an oven chamber to a temperature in the range of 950°C±50°C in oven crown and 900°C±50X in the sole flue. At this temperature coal or coal blend allowing the charged coal to be devolatilized and carbonized for a period in the range of 9 to 10 hrs for top charged condition and 12 to 13 hrs for stamp charge condition respectively. After carbonization, the hot coke mass quenched by water quenching method.
The coal blend used in the study was characterized by physical, chemical and petrographic analysis at Coal and Coke Testing Laboratory at Tata Steel Limited, Jamshedpur. The typical analysis of coal blend is shown in Table 1.

The trial was taken in 430 mm wide oven of non-recovery coke oven battery at HMC, Tata Steel Limited. This battery consists of series of ovens (03 numbers of ovens in each battery) including heating chambers. In stamp charge condition, the coal cake is charged from ram side of the battery while in top charge process the coal or coal blend charged from top of the oven.
In the ovens of this battery, the coal is charged in the form of coal cake (bulk density of charged coal cake is ~750 kg/cm3 and 1050 kg/cm3 for top charge and stamp charge respectively). The all other operating parameters like coal charge, coal granulometry, oven crown temperature, oven sole temperature and coking time were maintained identical for both top charge and stamp charge during the present invention.
Experimental results of coal blend samples like inherent moisture, ash, VM, maximum fluidity, softening temperature, resolidification temperature, maximum contraction, maximum expansion, Ro (avg.) and FSI are shown in Table 1. Results show that the all typical properties of charged coal blend are in good range.
Table 1: Typical properties of charged coal blend


Table 2 shows the operating parameters of the oven which were maintained during carbonization of coal blend. The carbonization tests were done for both top charges (BD: 750 kg/cm3) and stamp charge condition (1050 kg/cm3). Result depicts that the bulk density, moisture content and coking time in stamp charge condition is higher as compared to top charge condition. The other reaming parameters like charging temperature, oven crown temperature, sole flue temperature, and chimney temperature are almost constant for all tests.
Table 2: Operating Parameters of Coke Oven

Table 3 depicts the typical properties of test coke samples. Results show that the coke strength after reaction (CSR) is higher for stamp charge coke as compared to top charge coke which is obvious. The other properties like coke ash, coke volatile matter are more or less same.


Figure 8 and 9 present the typical temperature profile of oven crown and sole flue temperature during carbonization respectively. Results show that both oven crown and sole flue temperature profile is a quite good condition because charging of very little coal/coal blend inside the oven. Therefore, maintaining the thermal gradient is very important.
The developed process is very flexible to make or produce desired quality of coke in a better manner without bypassing of any non-recovery or heat recovery stamp charge process. This process is a unique and is first in kind idea.
The overall process flow sheet of non-recovery type ovens for the manufacture of metallurgical coke has been mentioned in Figure 1. The process equipment's used are oven, oven sole flue, oven flue tunnel, metallic tunnel for connecting the flue tunnel and chimney and chimney stack. In figure 1 of the drawings accompanying this specification schematic diagram of an oven for the production of metallurgical coke has been shown. It is a rectangular shape, arch-roofed (1) provided with charging hole at the rooftop of the oven (2) for charging coal and charging the coal cake from the ram side of the oven, a common flue tunnel (3) for burning of the uncombusted hydrocarbons. The partially combusted hydrocarbon burnt into the oven crown (4) and passes through downcomer pockets (5) and reached to oven sole flue (6) because the oven is operated at negative pressure. The oven crown and sole flue temperature were recorded with the help of

thermocouples which are fixed at oven roof (7) and oven sole (8). The oven crown and sole flue temperature controlled with the help of primary air. There is also an arrangement of tertiary air (9) for cooling the overheated raft. It is also used for oven sole temperature. The flue tunnel is connecting with chimney with the help of metallic tunnel (10). The hot exhaust of all three ovens exit in flue tunnel and after that goes to a common chimney stack (11) for releasing the hot exhaust of the ovens. The height of metallic chimney is fifteen meter which is suitable for creating the natural draft for smooth operation of the oven during coking.
Figure 2 of the drawing accompanying the specification schematic diagram of the top view of the oven and position of the downcomer pockets of the mini coke oven battery which is used for the production of metallurgical coke. The ovens besides having a chimney which is helpful for releasing the hot exhaust for each oven and therefore this arrangement is environment-friendly.
Figure 3 depicts the specification schematic diagram of the position of the downcomer pocket in the conjugated wall at the oven sole. The location of the pockets was decided with the help of heat and mass transfer study.
Figure 4 and 5 shows the schematic diagram of the movements of the heat in sole flues and flue tunnel of all three ovens. This unique arrangement of the heat movement will

help for efficient utilization of heat in oven sole flue. It has been described that the each of the oven soles has been provided with the double damper (1), the unique movement of the hot gas arrangement by circulating the hot flue (2), a single common chimney. The purpose of the double damper in each oven was to make the system more energy efficient which directly helps for producing the desired quality of metallurgical coke. While all the reported non-recovery type pilot coke ovens were not very energy efficient due to improper heat balance. Site supporting wall or cold zone (3, 4) are provided to prevent the heat loss from the sides of the oven. Two thermal distributors (5) are provided for each oven to guide the hot flue gas and distribute the heat uniformly throughout the oven, and hence efficient utilization of heat is done. The hot exhaust or hot flue finally leaves from the oven sole to the oven flue tunnel (6). The movement of hot exhaust or hot flue or heat (7) is moving towards chimney for final exit from the oven battery. There is also an arrangement of controlling the oven battery pressure, flue tunnel and chimney temperature, and one damper also provided at the end of flue tunnel (8). Also, there is a provision for expansion of refractory (9).

Figure 6 shows the schematic diagram of upper and lower door of the oven. The upper door (1) of the oven is fixed in oven refractory while the lower door (3) is operated during operation especially charging and pushing. The upper door of the oven having a circle pocket (2) which will help for providing the primary air to the oven for partial combustion of hydrocarbon inside the oven crown. The arrangement of the lower door was made with the help of solid iron rod bar (4) and two hinges (5). With the help of lid (6) of the circle pocket, the introduction of air can easily control. This is simple arrangement and easy to operate and maintenance.

WE CLAIM:
1. A device for the production of metallurgical coke comprising a batteryof ovens having a coking chamber with a temperature in the range of 950°C±50°C in oven crown and 900°C±50°C in the sole flue, a flue thermal is provided with charging stack when dry coke making air is admitted to the coking chamber in a controlled amount to burn the gaseous products distilled from coal to generate heat for complete carbonization and during coking process the produced hydrocarbon is combusted within the said oven which operates under negative pressure eliminating leakage from door and ports.
2. The device as claimed in claim 1, wherein carbonization of difficult type of coal blend stamp charge condition is adaptable to smooth operation of blast furnace.
3. A process for the production of metallurgical coke in a device as claimed in claim 1 comprising;
charging coal into an oven chamber to obtain devolatilized coal, subjecting the devolatilized coal to the step of carbonization, quenching the carbonized hot coke mass with water.
4. The process as claimed in claim 1, wherein the said coal is charged is to an oven at a
temperature in the range of 950°C±50°C in oven crown and 900°C±50°C in the sole
flue.

5. The process as claimed in claim 1, wherein said coal in carbonized for a period of 9 to 10 hours at top charged condition and 12 to 13 hours at stamp charge condition respectively.