FIELD OF INVENTION
The present application relates to a combination brick having two layers of refractories. In 5 particular, the present application pertains to a lining brick for a coke wharf comprising combination brick having one layer of silicon carbide (SiC) refractory and a second layer of fireclay refractory.
BACKGROUND OF INVENTION
10 Generally coal is converted into coke by heating coal blend charge in the coke ovens in the absence of air at a temperature of 1000°C to 1250°C for a period of about 16 to 48 hours. The volatile matter of coal liberated during carbonization is collected in gas collecting mains in the form of raw coke oven gas passing through stand pipes and direct contact cooling with ammonia liquor spray. The gas cooled from 800°C to 80°C is drawn to coal chemical plant
15 by exhauster. The residual coke is pushed out of the oven by pusher car through a guide into coke bucket. The red-hot coke is taken to coke dry cooling plant for cooling.
After the coking process, the coke is pressed out from the chamber onto the coke quenching car. To prevent it from burning down, it is quenched with water. After which the coke slides
20 onto the coke wharf at temperatures of ~120-150°C. Sometimes there are hot spots of unquenched coke inside the pile, which reach ~650-750°C. These burning spots are not treated and usually extinguished before the coke gets transported further on a rubber conveyor belt. During windy weather conditions this initial burning spots can spread to local fire on the coke wharf, destroying the coke and causing high thermal stress on the coke
25 wharf.
In such cases manual water quenching is conducted. After cooling down the coke is removed by a plough onto a conveyor belt for further transportation. The surface temperature on the coke wharf quickly drops to environmental temperature after exposure to ambient conditions. Hence, thermal shock of the wharf flooring takes place and strains the flooring out of ceramic 30 plates. The tiles crack and start chipping off and then break into pieces. Besides thermal stress, high wear loss is caused by the abrasive coke.
Another component which stresses the applied material in the coke wharf is chemical attack of corrosive elements in the surrounding environment. After quenching the coke, quenching
2

cars still contain a significant amount of quenching water which is spread onto the coke wharf. This water contains corrosive components from the coke, e.g. Ca2+, Cl-, SO42-, NO3-.
Currently the refractories used in the coke wharf include 45% alumina superduty fireclay bricks with apparent porosity: 14-15% and CCS: 400 – 550 kgf/cm2. The usual life for this 5 product is not more than 3 to 3.5 years. Refractory materials have improved continuously. However, there has not been any disruptive change in the last decade or so.
Predominantly used refractory bricks include monolithic, alumina, Magnesia-Chrome and Magnesia-Carbon bricks. However, these materials are having their own issues towards cost effectiveness. Hence fireclay bricks are widely used in lining of many coke wharfs.
10 Fireclay bricks have limited abrasion resistance, due to which localized erosion occurs in the coke wharf, thereby leading to wearing off the conventional brick linings on the coke wharf quite often. This happens as frequently as 3 years, leading to replacing the lining on the coke wharf, causing huge loss in terms of both time and money.
Therefore, in view of the technological landscape which is rapidly evolving around us, there 15 is a need to develop advanced refractory brick linings comprising combination bricks, with excellent abrasion resistance and long durability, which in turn increment energy efficiency, productivity with an effective cost management production and reasonable manufacturing costs.
OBJECT OF THE INVENTION
20 An object of the present invention is to provide a lining brick for a coke wharf comprising combination brick having two layers, one layer of silicon carbide (SiC) refractory and a second layer of fireclay refractory, for improving abrasion resistance of coke wharf brick lining.
25 Another object of the present invention is to provide a coke wharf comprising a plurality of lining bricks in accordance with the present disclosure, to enhance the longevity of the lining on the coke wharf.
Yet another object of the present invention is to a process for manufacturing coke in the coke 30 wharf of a coke oven, said coke wharf comprising a plurality of lining bricks in accordance with the present disclosure.

BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
Figure 1 provides a schematic diagram of the lining brick according to one of the
embodiments of the present application.
Figure 2 provides a schematic CAD representation of Silicon Carbide-Fireclay Combination
Brick according to one of the embodiments of the present application.
SUMMARY OF THE INVENTION
In one aspect, the present application provides a lining brick for a coke wharf comprising combination brick having two layers, one layer of silicon carbide (SiC) refractory and a second layer of fireclay refractory. The thickness ratio of SiC refractory to fireclay refractory in the lining brick is 1:3.
The present application also provides a coke wharf comprising a plurality of lining bricks in accordance with the present disclosure.
The present application further provides a process to manufacture coke in the coke wharf of a coke oven, said coke wharf comprising a plurality of lining bricks in accordance with the present disclosure.
The above summary is not intended to describe each embodiment or every implementation of the finding disclosed here. The Figures, Detailed description and Examples that follow more particularly exemplify these embodiments.
DETAILED DESCRIPTION OF THE INVENTION
For the purposes of the following detailed description, it is to be understood that the invention may assume various alternative variations and step sequences, except where expressly specified to the contrary. Moreover, other than in any operating examples, or where otherwise indicated, all numbers expressing, for example, quantities of ingredients used in the specification are to be understood as being modified in all instances by the term "about". It is noted that, unless otherwise stated, all percentages given in this specification and appended claims refer to percentages by weight of the total composition.

Thus, before describing the present invention in detail, it is to be understood that this invention is not limited to particularly exemplified systems or method parameters that may of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments of the invention only, and is not intended to limit the scope of the invention in any manner.
The use of examples anywhere in this specification including examples of any terms discussed herein is illustrative only, and in no way limits the scope and meaning of the invention or of any exemplified term. Likewise, the invention is not limited to various embodiments given in this specification.
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In the case of conflict, the present document, including definitions will control.
It must be noted that, as used in this specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the content clearly dictates otherwise. Thus, for example, reference to a “polymer” may include two or more such polymers.
The terms “preferred” and “preferably” refer to embodiments of the invention that may afford certain benefits, under certain circumstances. However, other embodiments may also be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, and is not intended to exclude other embodiments from the scope of the invention.
As used herein, the terms “comprising” “including,” “having,” “containing,” “involving,” and the like are to be understood to be open-ended, i.e., to mean including but not limited to.
In one aspect, the present application provides a lining brick for a coke wharf comprising combination brick having two layers, one layer of silicon carbide (SiC) refractory and a second layer of fireclay refractory. The thickness ratio of SiC refractory to fireclay refractory in the lining brick is 1:3.

Selection of refractory brick lining materials is quite critical for safe, stable, energy efficient and cost effective steel production. The refractory materials in accordance with the present disclosure retain heat at high operating temperatures ~ 1500 °C.
In accordance with an embodiment the thickness of SiC refractory is in the range of 20 to 40 mm. In a specific embodiment the thickness of SiC refractory is 25 mm.
In accordance with an embodiment the thickness of fireclay refractory is in the range of 35 to 55 mm. In a specific embodiment the thickness of fireclay refractory is 50 mm.
In accordance with an embodiment each of the SiC – Fireclay combination bricks have a length of 230 mm, width of 114 mm, and thickness of 75 mm.
The lining brick of the present invention comprises a combination brick: in a high percentage of SiC refractory content of at least 33.3 percent, by volume, based on the total volume percentage of the brick. In accordance with an embodiment the SiC refractory is present in the range of 25 to 50 volume percentage. In a specific embodiment SiC refractory is present in 33.3 volume %.
SiC refractory is best suited for the combination brick in the present application because of the properties such as excellent abrasion resistance, thermal shock resistance, strength and thermal elasticity. The combination of SiC with fireclay is perfect because both the refractory materials have almost similar pattern reversible thermal expansion coefficient which is in the range of 4.5 to 6.0 X 10-6 in/in oC.
SiC refractory has excellent thermal elasticity, thereby increasing strength with increase in temperature. Also, above 800°C SiC gets oxidised and forms a protective layer on the refractory, thereby enhancing the life of the refractory.
The lining brick in accordance with the present disclosure comprises a combination brick: in a lower percentage of SiC in the SiC refractory with a content of at least 85 percent, by weight, based on the total weight percentage of the SiC refractory. In accordance with an embodiment the SiC present in the SiC refractory is in the range of 70 to 90 weight

The lining brick in accordance with the present disclosure comprises a combination brick: in a lower percentage of alumina in the fireclay refractory with a content of at least 35 percent, by weight, based on the total weight percentage of the fireclay refractory. In accordance with 5 an embodiment the alumina present in the fireclay refractory is in the range of 35 to 55 weight percentage. In a specific embodiment alumina in fireclay refractory is present in 45 weight %.
In accordance with an embodiment the fireclay refractory is present in the range of 50 to 75 10 volume percentage. In a specific embodiment fireclay refractory is present in 66.7 volume %.
Fireclay refractory has high mechanical resilience, insoluble in water, super-heated steam, and most inorganic acids and alkalies. It has a high resistance in oxidizing and reducing atmosphere. Typically fireclay contains mullite, which can attribute to thermal shock 15 resistance and volume stability. The fireclay refractory in accordance with the present disclosure comprises alumina with little traces of impurities. In an embodiment molochite is used in the fireclay refractory as a combination in the lining brick for coke wharf operating up to 1250˚C.
20 The lining brick in accordance with the present disclosure is substantially free of carbon. In an embodiment the SiC refractory, comprises SiC and mullite phases.
In a further embodiment the fireclay refractory comprises mullite phase. Mullite phase is associated with low thermal expansivity, high thermal conductivity, good thermal shock 25 resistance, high high-temperature strength, thereby resisting high temperature for long term without softening.
Generally it is essential for a refractory material to withstand the action of abrasive or corrosive solids, liquids or gases at high temperatures. The various combinations of operating 30 conditions, in which refractories are used, make it necessary to manufacture a range of refractory materials with different properties.

present disclosure can withstand high temperatures, load and abrasive forces.
5 In accordance with an embodiment the lining brick can also withstand sudden changes of temperatures and heavy load at service conditions.
In accordance with an embodiment the cold crushing strength of SiC refractory in the range of 800 to 1500 kg/cm2. In a specific embodiment the cold crushing strength of SiC refractory 10 is 1300 kg/cm2.
In accordance with an embodiment the cold crushing strength of fireclay refractory in the range of 300 to 700 kg/cm2. In a specific embodiment the cold crushing strength of fireclay refractory is 450 kg/cm2.
15
The cold crushing strength determines the resistance of the refractory to crushing, which plays a vital role during transport, i.e., during loading of the coke onto the coke wharf. It only has an indirect relevance to the combination brick refractory performance, and is therefore used as one of the major indicators of abrasion resistance of the combination brick. Other
20 indicating properties include bulk density, porosity, Abrasion Resistance (ASTM C-704), the refractory particles and its resistance to the flow of high-velocity particles across its surface. The need for good abrasion resistance of refractory materials is most evident in various refractory applications where localised impact happens at moderately elevated temperatures. A direct correlation between abrasion resistance and cold crushing strength has been
25 established. Thus, the cold crushing strengths can provide a direct indication about, the predictability of a refractory material regarding its resistance to abrasion.
In accordance with an embodiment the apparent porosity of SiC refractory is in the range of 7 to 18%, at least in the range of 10 to 18%. In a specific embodiment, the apparent porosity of 30 SiC refractory is 15%. In accordance with an embodiment the apparent porosity of fireclay refractory is in the range of 10 to 18%, at least in the range of 14 to 18%. In a specific embodiment, the apparent porosity of alumina refractory is 16%.

In accordance with an embodiment the bulk density of SiC refractory is in the range of 2.45g/cc to 2.55 g/cc. In a specific embodiment, the bulk density of SiC refractory is 2.5 g/cc. In accordance with an embodiment the bulk density of alumina refractory is in the range of 2.2 g/cc to 2.45 g/cc. In a specific embodiment, the bulk density of alumina refractory is 2.3 g/cc.
The bulk density of the SiC and fireclay refractory combination brick increases the bricks volume stability, heat capacity, strength and most importantly increases the abrasion resistance.
In accordance with an embodiment abrasion resistance (as per ASTM C704/C704M) of SiC refractory in the range of 4.0 to 5.0cc. In a specific embodiment the abrasion resistance of SiC refractory is 4.5 cc.
In accordance with an embodiment abrasion resistance (as per ASTM C704/C704M) of alumina refractory in the range of 8.0 to 10.0cc. In a specific embodiment the abrasion resistance of SiC refractory is 8.8 cc.
In another aspect the present application also provides a coke wharf comprising a plurality of lining bricks in accordance with the present disclosure.
The lining brick for the coke wharf comprises a combination brick having two layers, one layer of silicon carbide SiC refractory and a second layer of fireclay refractory. The thickness ratio of SiC refractory to fireclay refractory in the lining brick is 1:3.
In accordance with an embodiment the fireclay refractory sides the surface of the of the coke wharf, such that the coke is loaded on the surface of the SiC refractory. The fireclay refractory layer supports the SiC refractory layer to enhance the life of coke wharf. The SiC refractory supports the temperature, rapid change in surface temperatures and abrasion forces exerted by the coke movement on coke wharf surface.
In yet another aspect the present application also provides a process to is to manufacture coke in the coke wharf of a coke oven. The coke is manufactured in conventionally known methods, wherein the coke wharf is in accordance with the present disclosure comprising a

plurality of lining bricks in accordance with the present disclosure, to enhance the longevity of the lining on the coke wharf.
In an embodiment the fireclay refractory sides the surface of the of the coke wharf, such that 5 the coke is loaded on the surface of the SiC refractory.
This lining brick for a coke wharf comprising the combination brick in accordance with the present disclosure provides an economic solution for improving abrasion resistance of the Coke Wharf Brick lining.
0 The following examples are provided to better illustrate the claimed invention and are not to be interpreted in any way as limiting the scope of the invention. All specific materials, and processes described below, fall within the scope of the invention. These specific compositions, materials, and processes are not intended to limit the invention, but merely to
5 illustrate specific embodiments falling within the scope of the invention. One skilled in the art may develop equivalent materials, and processes without the exercise of inventive capacity and without departing from the scope of the invention. It is the intention of the inventors that such variations are included within the scope of the invention.

INFERENCE:
It is evident from the data contained in Table 1, that the SiC-Fireclay combination brick according to the present application (Inventive example 1) exhibits excellent abrasion resistance and enhanced longevity of the disclosed lining brick. The comparative examples in 1-2 using fireclay refractory and high alumina refractory alone have not achieved a longer life and abrasion resistance which is a critical attribute required for an excellent lining brick combination.

We Claim:
1. A lining brick for a coke wharf comprising combination brick having two layers, one layer
of silicon carbide (SiC) refractory and a second layer of fireclay refractory,
wherein the thickness ratio of SiC refractory to fireclay refractory in the lining brick is 1:3.
2. The lining brick as claimed in claim 1, wherein the thickness of SiC refractory is in the range of 20 to 40 mm.
3. The lining brick as claimed in claim 1, wherein the thickness of fireclay refractory is in the range of 35 to 55 mm.
4. The lining brick as claimed in claim 1 having a length of 230 mm, width of 114 mm, and thickness of 75 mm.
5. The lining brick as claimed in claim 1, wherein SiC refractory is present in the range of 25 to 50 volume percentage.
6. The lining brick as claimed in claim 1, wherein the fireclay refractory is present in the range of 50 to 75 volume percentage.
7. The lining brick as claimed in claim 6, wherein alumina in fireclay refractory is present in the range of 35 to 55 weight percentage.
8. The lining brick as claimed in claim 6, wherein SiC in SiC refractory is present in the range of 70 to 90 weight percentage
9. The lining brick as claimed in claim 1, wherein apparent porosity of SiC refractory is in the range of 7 to 18%.
10. The lining brick as claimed in claim 1, wherein apparent porosity of fireclay refractory is
in the range of 10 to 18%.

11. The lining brick as claimed in claim 1, wherein cold crushing strength of SiC refractory in the range of 800 to 1500 kg/cm2.
12. The lining brick as claimed in claim 1, wherein cold crushing strength of fireclay refractory in the range of 300 to 700 kg/cm2.
13. The lining brick as claimed in claim 1, wherein abrasion resistance (as per ASTM C704/C704M) of SiC refractory in the range of 4.0 to 5.0cc.
14. The lining brick as claimed in claim 1, wherein abrasion resistance (as per ASTM C704/C704M) of fireclay refractory in the range of 8.0 to 10.0cc.
15. A coke wharf comprising a plurality of lining bricks as claimed in claim 1.
16. The coke wharf as claimed in claim 15, wherein the fireclay refractory sides the surface of the of the coke wharf, such that the coke is loaded on the surface of the SiC refractory.