, Description:TECHNICAL FIELD
[0001] The present disclosure relates to the utilization of non-coking coal for metallurgical coke making with the addition of industrial by-product based polymeric additive. More particularly, the present disclosure relates to a process to utilize non-coking coal for producing a metallurgical coke.
BACKGROUND
[0002] Background description includes information that may be useful in understanding the present subject matter. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed subject matter, or that any publication specifically or implicitly referenced is prior art.
[0003] Metallurgical coke serves significant purposes in a blast furnace to produce pig iron. It is used as a fuel, as well as a reducing agent and is accountable for the permeability of the charge. Because of the various roles of coke in a blast furnace, stringent physical and chemical properties of the coke is required to ensure smooth operation and high productivity in modern blast furnaces.
[0004] Because of the high price of prime coking coal and the limited reserve of prime coking coal worldwide, one of the most significant subjects for steel industry today is the maximum utilization of non-coking coal in a blend to produce high-strength coke. Hence, a technology without reducing the quality and with increasing the blending ratio of the non-coking or slightly caking coals is desired. Nowadays, considerable research is going on to develop alternate carbonaceous additive material, which can improve the coke quality of non-coking coal. Various literature review reveals that the fluidity of coal matrix is equivalent to the H present in the coal matrix. Also, the evolution of hydrogen plays an important role to stabilize the metaplast in the fluidic regime.
[0005] Indian steel plants have also tried pure as well as modified phenol-formaldehyde based resin as an additive to enhance the coke properties of non-coking coal. Successful trials were conducted in heat recovery oven of steel plants.
[0006] Further, as the reserve of prime coking coal is inadequate in India, various methods to enhance the coking potential of weakly coking or non-coking coals have been studied as alternatives to importing more expensive, better quality coals. Utilization of additives is one of the options to get better quality of coke. These additives can be organic or inorganic in nature and have been used in both solid and liquid form as binders in coal briquettes or as direct additions to the coal blend.
[0007] The use of blends of coals of different origin and quality is the regular exercise in coke making industry. Furthermore, other types of carbonaceous materials as additives. [See; (i) G. Collin, B. Bujnowska. Co-carbonization of pitches with coal mixtures for the production of metallurgical cokes. Carbon 32 (1994) 547-552; (ii) C. Barriocanal, R. Alvarez, C. S. Canga, M. A. Diez. On the possibility of using coking plant waste materials as additives for coke production. Energy & Fuels 12 (1998) 981-989; (iii) S. Nomura, K. Kato, T. Nakagawa, I. Komaki.].
[0008] The effect of plastic addition on coal caking properties during carbonization. Fuel 82 (2003) [1775-1782] are also included in the preparation of industrial coal blends for coke production. Different types of additives such as anthracite and bituminous materials like coal tar, coal-tar pitch [(iv) M. J. Gonzalez-Cimas, J. W. Patrick, A. Walker. Influence of pitch additions on coal carbonization: coke strength and structural properties. Fuel 66 (1987) 1019–1023; and (v) S. Nomura, T. Arima. Influence of binder (coal tar and pitch) addition on coal caking property and coke strength. Fuel Processing Technology 159 (2017) 369–375.] can be introduced in the coke oven.
[0009] Addition of binders like coal tar pitch to the coal blend, prior to stamping is expected to reduce the consumption of thermal energy and would impart the requisite strength and stability at lower moisture levels. Coal-tar pitch has been recognized as a suitable active plasticizing agent during the co-carbonization processes. The proper chemical composition, mainly of an aromatic nature [M. Zander. Pitch: the science of future material. Fuel 66 (1987) 1457-1608.], and good coking properties are all the advantages of coal-tar pitch as a blend component. Moreover, pitch addition improves the strength characteristics of the resultant coke made from coals having poor rheological properties.
[0010] Furthermore, materials derived from petroleum processing have also been used as additives in coke production. Nomura et al. [(v) S. Nomura, T. Arima. Influence of binder (coal tar and pitch) addition on coal caking property and coke strength. Fuel Processing Technology 159 (2017) 369–375.] has reported the interaction between semi-soft coking coal and petroleum-derived binder enhanced caking property and coke strength. However, these additives usually contain high sulfur content, emit a high amount of pollutants or result in a certain reduction of the coke quality.
[0011] Considering the importance of the thermoplastic properties of a coal for the development of coke structure, the effect of addition of soluble or deposit prepared from degradative solvent extraction of biomass (waste sawdust) on coal markedly enhanced the coke quality through increasing coke strength after reaction (CSR) and reducing CRI [(vii) H. B. Vuthaluru. Thermal behavior of coal/biomass blends during co-pyrolysis. Fuel Processing Technology 85 (2003) 141–155; (viii) M. G. Montiano, E. Diaz-Faes, C. Barriocanal, R. Alvarez. Influence of biomass on metallurgical coke quality. Fuel 116 (2014) 175–182.]. The soluble and deposit has significantly higher carbon content, lower oxygen groups (such as –OH groups) and extremely lower ash content, and hence it acts as a good additive for coke-making.
[0012] Another organic additive utilized in coke making is a different type of plastics [(ix) M. Ibrahim, E. Hopkins, M. S. Seehra. Thermal and catalytic degradation of commingled plastics. Fuel Processing Technology 49 (1996) 65-73.]. Literature review shows that the addition of 2 wt % of plastic waste causes a decrease in the maximum fluidity of the coal during thermal heating between 400 and 500 °C. The extent of the reduction of coal fluidity is influenced by the thermal behavior of the plastic waste itself, the composition of the pyrolysis products and consequently the hydrogen donor and acceptor abilities of the polymer [(x) M. A. Diez, C. Barriocanal, R. Alvarez. Plastic wastes as modifiers of the thermos plasticity of coal. Energy & Fuels 19 (2005) 2304-2316]. The polyolefin such as High Density Polyethylene (HDPE), Low Density Polyethylene (LDPE), polypropylene, which show a higher temperature of maximum volatile release, reduce coal fluidity to a lesser extent than the other polymers like polystyrene, polyethylene terephthalate because of the presence of aromatic rings in the polymer chain and a loss of volatile matter in the coal at pre-plastic stage.
[0013] Furthermore, in past, few patents are granted on the synthesis of resin-based binder, e.g., CN104531023 (preparation of epoxy resin binder), KR101547492 (polyamide resin binder), WO2015107811 (cellulose derived resin binder), etc. These binders are mostly manufactured for refractory uses (JP5727241), for ferrite sintered compounds (JP2012101279), for metal powder injection molding (JP2003286503). There is no patent found on the application of resin-based binder for improvement of coking potential of non-coking coal. Recently, Tata Steel’s patent application is published on different derivatives of phenol-formaldehyde resin which is used to induce the coking potential to non-coking coal (IN201731039496).
[0014] Phenol based resol type resin was used as a binder in coke making and the effects of the binder on coke strength studied by Nag et al. [(xi) D. Nag, R. Singh, S. Shome, P. K. Banerjee, V. K. Saxena. Use of organic binder in coke making. Ironmaking and Steelmaking 42 (2015) 112-116]. The results have indicated that the addition of binder improves the coke hot strength (CSR) and coke cold strength (M40). The thermal degradation of phenolic resin affects the carbonization process due to the presence of integral chemistry of resin such as cross-linking methylene bridges, partial cyclization, and aromatization of the macromolecular network.
OBJECTS OF THE DISCLOSURE
[0015] Some of the objects of the present disclosure, which at least one embodiment herein satisfy, are listed hereinbelow.
[0016] A general object of the present disclosure is to synthesis cross-linked polymeric compound derived from steel industry by-product based precursor (coal tar) material for utilizing non-coking coal in a coal blend.
[0017] Another object of the present disclosure is to use non-coking coal in a coal blend without deterioration of coke properties
[0018] Another object of the present disclosure is to provide maximum utilization of non-coking coal in a coal blend to produce metallurgical coke with the addition of modified coal tar-based polymeric additive.
[0019] These and other objects and advantages of the present invention will be apparent to those skilled in the art after a consideration of the following detailed description taken in conjunction with the accompanying drawings in which a preferred form of the present invention is illustrated.

SUMMARY
[0020] This summary is provided to introduce concepts related to a process to utilize non-coking coal for producing a metallurgical coke. The concepts are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
[0021] The present disclosure relates a process to utilize non-coking coal for producing a metallurgical coke. The process includes synthesizing a cross-linked polymeric additive from a low moisture and low quinoline-insoluble (Q.I) based coal tar and formaldehyde based precursor; and mixing the cross-linked polymeric additive with a coal blend in a specific dosage of 1-2 % (by wt).
[0022] In an aspect, the cross-linked polymeric additive includes solid content 61.5-63.5 %, fixed carbon 29.0 to 31.0 % and moisture 0.5-0.6 % (by wt.).
[0023] In an aspect, the cross-linked polymeric additive comprises C-C-O group of phenolic moieties, aromatic C=C groups and cross-linking moiety (aliphatic and aromatic -CH group).
[0024] In an aspect, the synthesizing cross-linked polymeric additive comprising steps of: dissolving the low moisture and low Q.I based coal tar in N, N-dimethyl formamide (DMF) solvent with heating at 80-90 °C for 2-3 hrs; adding a 2.5 – 3.5% (by wt.) conc. sulfuric acid into the homogeneous solution of coal tar and the DMF solvent to create a reaction mixture, the DMF solvent being configured to stable the material in the liquid phase; mixing 10-15% (by wt.%) of formaldehyde into the reaction mixture at the temperature of 80-90 °C for 2-3 hours; adding a specified amount of cross-linker hexamine 1.25 to 1.75% (by wt.) into the reaction mixture while maintaining the temperature at 80-90 °C for 2-3 hours, so as to convert the reaction mixture into a cross-linked polymeric additive; distilling out water formed during the conversion of the cross-linked polymeric additive; and cooling the cross-linked polymeric additive to room temperature.
[0025] In an aspect, the cross-linked polymeric additive comprises 75-80 % (by wt.%) coal tar.
[0026] In an aspect, the coal blend is prepared from different types of coal including semi-soft coal, hard coking coal, and non-coking coal.
[0027] In an aspect, the coal blend comprises non coking coal 10-15%, hard coking coal is 35-45%, and semi soft is 50-55% (by wt).
[0028] In an aspect, the cross-linked polymeric additive enables to accommodate 10-15 % non-coking coal in the coal blend.
[0029] In an aspect, the coal tar is a low moisture coal tar having moisture 1-2% (by wt.).
[0030] In an aspect, the coal tar has the low QI of 1-2.5 %.
[0031] The present disclosure further relates to a cross-linked polymeric additive to be used in a coal blend, comprising solid content 61.5-63.5 %, fixed carbon 29.0 to 31.0%, moisture 0.5-0.6% (by wt.), specific gravity 1.16 – 1.20 (at 25 °C) and viscosity 1800-2000 cP (at 25 °C ).
[0032] In an aspect, the cross-linked polymeric additive comprises C-C-O group of phenolic moieties, aromatic C=C groups and cross-linking moiety (aliphatic and aromatic -CH group).
[0033] In an aspect, the cross-linked polymeric additive has model structure

[0034] In an aspect, the cross-linked polymeric additive comprises 75-80 % (by wt.) coal tar.
[0035] Various objects, features, aspects, and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.
[0036] It is to be understood that the aspects and embodiments of the disclosure described above may be used in any combination with each other. Several of the aspects and embodiments may be combined to form a further embodiment of the disclosure.
[0037] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0038] The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate exemplary embodiments and, together with the description, serve to explain the disclosed principles. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of system and/or methods in accordance with embodiments of the present subject matter are now described, by way of example only, and with reference to the accompanying figures, in which:
[0039] FIG. 1 illustrates a process to utilize non-coking coal for producing a metallurgical coke, in accordance with an embodiment of the present disclosure;
[0040] FIG. 2 illustrates a schematic representation of the synthesis of cross-linked polymeric additive, in accordance with an embodiment of the present disclosure; and
[0041] FIG. 3 illustrates Fourier-transform infrared spectroscopy (FITR) spectra for cross-linked polymeric additive, in accordance with an embodiment of the present disclosure.
DETAILED DESCRIPTION
[0042] In the present document, the word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment or implementation of the present subject matter described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.
[0043] While the disclosure is susceptible to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the drawings and will be described in detail below. It should be understood, however that it is not intended to limit the disclosure to the forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternatives falling within the scope of the disclosure.
[0044] The terms “comprises”, “comprising”, “includes” or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a setup, device or method that includes a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such setup or device or method. In other words, one or more elements in a system or apparatus proceeded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or method.
[0045] In the following detailed description of the embodiments of the disclosure, reference is made to the accompanying drawings that form a part hereof, and in which are shown by way of illustration specific embodiments in which the disclosure may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, and it is to be understood that other embodiments may be utilized and that changes may be made without departing from the scope of the present disclosure. The following description is, therefore, not to be taken in a limiting sense.
[0046] Hereinafter, a description of an embodiment related to a process to utilize non-coking coal for producing a metallurgical coke. The present disclosure synthesized a new kind of low-cost modified coal tar-based cross-linked polymeric additive which can open new window in coke making process for replacing prime hard coking coals by inferior weakly coking / non-coking coals. Here, modified coal tar-based additive is designed through cross-linking polymerization technique using formaldehyde treatment on coal tar. Herein, coal tar is basically selected as a precursor for additive synthesis due to its low-price, sustainable availability at bulk scale in steel industry, and owing to its interesting physical and chemical properties like easy flowability, lower viscosity, and existence of abundant aromatic components like phenol and its derivative, and polyaromatic hydrocarbon. This coal tar-based cross-linked polymer during addition at lower percentage (1-2 %) in a coal blend can accommodate higher percentage (10-15 %) of non-coking coal in the blend without deterioration of coke properties. Furthermore, in an aspect, 7 kg carbonization study of non-coking coal enriched coal blend reflects that this cross-linked polymeric additive shows considerable improvement of coke strength after reaction (CSR).
[0047] FIG. 1 illustrates a process 100 to utilize non-coking coal for producing a metallurgical coke, according to an embodiment of the present disclosure. The order in which the process 100 is described is not intended to be construed as a limitation, and any number of the described process blocks can be combined in any appropriate order to carry out the process 100 or an alternative process. Additionally, individual blocks may be deleted from the process 100 without departing from the scope of the subject matter described herein.
[0048] At block 102, the process 100 includes synthesizing a cross-linked polymeric additive from a low moisture and low quinolone-insoluble (Q.I) based coal tar and formaldehyde based precursor. In an aspect, in a synthetic procedure, the coal tar dissolved in N, N- dimethyl formamide (DMF) solvent in the desired ratio and heated at 80-90 °C for 2-3 hours. Then, the required amount, say 2.5-3.5 % (by wt.) of conc. sulfuric acid added to the homogeneous solution of coal tar and the DMF solvent to create a reaction mixture, where the DMF solvent is being configured to stable the material in the liquid phase. Then, desired amount, say 10-15% (by wt.%), of formaldehyde is mixed into the reaction mixture and temperature is maintained at 80-90 °C for 2-3 hours. Thereafter, specific amount, 1.25 to 1.75% (by wt.), of cross-linker hexamine is added into the reaction mixture and again heated at 80-90 °C for 2-3 hours. Finally, the entire mass was converted to a polymer and the extra water formed during reaction is distilled out. Finally, the cross-linked polymeric additive is cooled to room temperature. The synthesized cross-linked polymeric additive is marked as CTFP and schematic representation is reflected in FIG. 2. Herein, crosslinking polymerization is taken place through phenolic component of coal tar with formaldehyde molecule. Simultaneously, H-bonding interaction between hexamine and phenolic moiety of coal tar provides the desired stability to the product and forms a well cross-linked network structure.
[0049] Physical properties of synthesized coal tar-based cross-linked polymeric additive are mentioned as follows:
• Appearance: Black viscous liquid
• Solubility: Insoluble in water; soluble in DMF
• Specific gravity (at 25 °C): 1.18
• Viscosity (at 25 °C): 2000 cp
• pH: 4.5
• Solid Content: 62.47 %
• Fixed Carbon: 29.54 %
• Ash Content: 0.0 %
• Moisture Content: 0.6 %
[0050] Furthermore, Fourier-transform infrared spectroscopy (FTIR) spectrum (FIG. 3) of the polymer CTFP shows the symmetric and asymmetric stretching vibrations for C-C-O group of phenolic moieties at 1080 cm-1 and 1190 cm-1, respectively. The peaks at 1385 cm-1 are associated with the C–H bending vibration. The emerging peaks at 1435 cm-1 are attributed to -CH2 deformation vibration indicating the presence of cross-linking moiety. The peak for aromatic C=C stretching vibration is observed at 1645 cm-1. The peak at 2925 cm-1 is due to the presence of cross-linking/aliphatic -CH stretching vibration. The peak associated at 3052 cm-1 is responsible for Aromatic -CH stretching mode. The peaks at 3405 cm-1 are associated with the O–H stretching vibration of phenolic moiety present in the polymer structure.
[0051] Returning to FIG. 1, at block 104, the process 100 includes mixing the cross-linked polymeric additive with a coal blend in a specific dosage of 1-2 % (by wt). In an example, the coal blend comprises non coking coal 10-15%, hard coking coal is 35-45%, and semi soft is 50-55% (by wt). In an aspect, the cross-linked polymeric additive comprises solid content 61.5-63.5 %, fixed carbon 29.0 to 31.0% and moisture 0.5-0.6% (by wt.). In another aspect, the cross-linked polymeric additive comprises C-C-O group of phenolic moieties, aromatic C=C groups and cross-linking moiety (aliphatic and aromatic -CH group).
[0052] In an aspect, the cross-linked polymeric additive has model structure

[0053] In an aspect, the cross-linked polymeric additive comprises 75-80 % (by wt.) coal tar.
[0054] Thereafter, the coals are characterized in terms of ash, volatile matter (VM), crucible swelling number (CSN) and fluidity.
[0055] The details of the tests are as follows:
Ash Analysis:
[0056] Ash is determined by following ASTM standard D 3174-11. 1 gm of 250 mm size sample is taken to a weighed capsule. Then the sample is placed in a cold muffle furnace and heated gradually at such a rate that the temperature is reached from 450 °C to 500 °C by 1 hour. At the end of 2 hours, it will reach 950 °C. After cooling, the weight of the sample is measured and ash is calculated by weight difference.
VM Analysis:
[0057] Ash is determined by following ASTM standard D 3175-11. In this test 1 gm of 250 mm size sample is taken in a covered platinum crucible and heated in a furnace of 950 °C for 7 minutes. The VM is calculated by weight difference.
Crucible swelling number (CSN):
[0058] Crucible swelling number test is done by following ASTM D720-91 (2010). In which, 1 gm of a sample (-0.212 mm size) is taken in a translucent squat shaped silica crucible and the sample is leveled by tapping the crucible 12 times. The crucible is covered with a lid and heated under standard conditions, either by a special type of gas burner or muffle furnace. After the test, the shape of the coke button is compared with a standard chart and accordingly, the crucible swelling number (0 to 9) is assigned to the coal sample.
Table 1: Properties of different coal samples
Coal Ash VM CSN
Coal A 19.74 18.33 7
Coal B 22.07 15.49 5.5
Coal C 19.50 7.33 5
Coal D 23.72 10.80 8
Coal E 9.51 27.17 7
Coal F 9.68 15.08 1.5

[0059] Different coals have been used for blend preparation. Coal A is captive hard coking coal. Coal B is captive semi-soft coal. Coal C is imported semi-soft coal. Coal D and Coal E are imported hard coking coal. Coal F is non-coking coal.
Carbonization study
[0060] A series of carbonization tests were carried to study the influence of the polymeric additive on coke properties. A number of carbonization tests were conducted in the 7-kg carbonite oven, under stamp charging conditions. Water was added to the coal blend to obtain the desired value of moisture content. The coal cake was made inside a cardboard box keeping the bulk density 1150 kg/m3. Tests were done with different blends. Initially, a test carried out with base blend (blend no 1). Then, the hard-coking coal from the base blend is replaced by non-coking coal. Optimized quantity of polymeric additive is mixed to maintain the coke quality. Before charging the coal cake into the oven, it was ensured that the empty oven temperature is 900±5°C. After 5 hours. of carbonization time, the hot coke was pushed out and quenched with water. The coke samples were tested for coke strength after reaction (CSR) and CRI (coke reactivity indices).
[0061] In an exemplary plant, steel coke strength after the reaction is studied using the NSC method. In which, 200 gm coke of 19-21 mm size is heated in a reaction tube (78 mm diameter X 210 mm length) at 1100 °C for two hours and CO2 is passed a 5 L/minute. The percentage loss in weight of coke during the above reaction is reported as the coke reactivity test (CRI). This reacted coke is further tested by rotating in an I drum (127 mm diameter X 725 mm length) for 30 min at a speed of 20 rpm. The coke is then screened on 10 mm sieve and the % of + 10 mm fraction is reported as the coke strength after reaction (CSR).
Carbonization result
Table 2: The blend composition and coking properties
Blend 1 2 3 4 5 6 7 8 9 10
Component, %
Coal A 15 15 15 15 15 15 15 15 15 15
Coal B 35 35 35 35 35 35 35 35 35 35
Coal C 20 20 20 20 20 20 19 18 20 20
Coal D 15 10 10 10 10 10 10 10 10 10
Coal E 15 10 10 10 8 8 8 8 5 5
Coal F 0 10 9.5 9 12 11 11 11 15 14
CTFP 0 0 0.5 1 0 1 2 3 0 1
CSR 50.6 41.1 42.9 46.7 42.1 46.6 48.7 43.8 29.3 53.1

[0062] Herein, blend 1 is the base blend of the coke plant. In blend 2, 10% of non-coking coal is added in place of imported hard coking coal i.e. Coal D (5%) and Coal E (5%). The result shows that the CSR value has been dropped from 50.6 to 41.1. In blend 3, 0.5 % of CTFP additive is added and improvement of CSR value of 42.9 from 41.1 is observed. In blend 4, after the addition of 1% of polymer CSR value is increased to 46.7 from 42.9. In blend 5, 12% of non-coking coal is added in place of imported hard coking coal i.e. Coal D (5%) and Coal E (7%) but the CSR value is dropped to 42.1 from 50.6. In blend 6 to 8, for addition of 1% to 3% of CTFP additive, CSR value is increased to 46.6, 48.7 and 43.8 respectively. In case of blend 9, 15% non-coking coal is added in place of imported hard coking coal i.e. Coal D (5%) and Coal E (10%) and CSR value are dropped to 29.3. However, in blend 10, after addition of 1% polymer, CSR value is increased to 53.1. This indicates that 1 % addition of the CTFP additive has potential to replace around 15 % of prime hard coking coal by non-coking coal.

Mechanism of coal tar-based cross-linked polymeric additive
[0063] It has been well established that the most significant range of temperature during coke-making is 350–550 °C, when the coal exists in the form of a plastic phase that finally resolidifies to give semi-coke. The behavior of coal blends in the plastic zone depends on the amount and the quality of bitumens existing in the parent coals and can be modified by incorporating additives into the blend. The relevant characteristics of additives are aromaticity, alkyl substitution, heteroatoms, and reactive functional group concentration and chemical compatibility with coal. [See, I. Mochida, K. Itoh, Y. Korai, T. Shimohara. Carbonization of Canadian weathered coal into anisotropic coke. Fuel 65 (1986) 429-432].
[0064] Herein, p-p stacking interaction between the delocalized aromatic structure of coal and well crosslinked polymeric moiety of CTFP additive plays a crucial role in coal cake formation. In addition, CTFP additive has an oxygen functional group, which form hydrogen bonds with coal structure, resulting inhibition of volatilization of small aromatic clusters of non-coking coal. Also, this polymeric additive has higher viscosity and its boiling point is comparatively high, and more fraction of poly-aromatic hydrocarbons present in modified coal tar-based product, which is helpful for carbonization process. As a result, the additive-enhanced the coal plastic property. The transferable hydrogens released from the polymeric additive during plastic phase plays the crucial for polycondensation reaction of coal structure at 350–550 °C temperature and is helpful for semi coke structure formation. In addition, methylene cross-linking moiety present in polymeric structure provides desired free radical binding site and it accelerates re-aromatization process of coal structure at plastic phase via free radical mechanism pathway, resulting structural ordering of semi-coke. In summary, the presence of well-crosslinked polymeric structural chemistry of CTFP, existence of higher percentage PAH moiety of coal tar and availability of H-bonding site in additives plays the crucial role during carbonization of non-coking coal.
TECHNICAL ADVANTAGES
[0065] The present disclosure provides organic polymeric additive synthesized on a single pot system and which is easily scalable.
[0066] The present disclosure provides polymeric additive which is cost-effective, i.e., the reaction takes low temperature and reaction time.
[0067] The present disclosure provides a mechanism by which sustainable steel industry by-product based precursor material, i.e., coal tar, is used to develop the polymeric additive.
[0068] The present disclosure provides a synthesized product in which homogeneous and organic solvent DMF is used to stable the material in the liquid phase.
[0069] Further, the existence of well-crosslinked polymeric network, higher percentage of PAH moiety and availability of H-bonding site are the basis for synthesis of polymeric additives and these properties plays a crucial role during carbonization of non-coking coal.
[0070] The polymeric additives proposed herein are used to improve the coking potential of inferior coals.
Equivalents:
[0071] The specification has described a process to utilize non-coking coal for producing a metallurgical coke. The illustrated steps are set out to explain the exemplary embodiments shown, and it should be anticipated that ongoing technological development will change the manner in which particular functions are performed. These examples are presented herein for purposes of illustration, and not limitation. Further, the boundaries of the functional building blocks have been arbitrarily defined herein for the convenience of the description. Alternative boundaries can be defined so long as the specified functions and relationships thereof are appropriately performed. Alternatives (including equivalents, extensions, variations, deviations, etc., of those described herein) will be apparent to persons skilled in the relevant art(s) based on the teachings contained herein. Such alternatives fall within the scope and spirit of the disclosed embodiments. Also, the words "comprising," "having," "containing," and "including," and other similar forms are intended to be equivalent in meaning and be open-ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items. It must also be noted that as used herein and in the appended claims, the singular forms “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise.
[0072] Finally, the language used in the specification has been principally selected for readability and instructional purposes, and it may not have been selected to delineate or circumscribe the inventive subject matter. It is therefore intended that the scope of the invention be limited not by this detailed description, but rather by any claims that issue on an application based here on. Accordingly, the embodiments of the present invention are intended to be illustrative, but not limiting, of the scope of the invention, which is set forth in the following claims.

Claims:1. A process for utilizing non-coking coal in a coal blend for producing a metallurgical coke, the process comprising steps of:
synthesizing a cross-linked polymeric additive from a low QI based coal tar and formaldehyde based precursor; and
mixing the cross-linked polymeric additive with a coal blend in a specific dosage of 1-2 % (by wt).
2. The process as claimed in claim 1, wherein the cross-linked polymeric additive comprises solid content 61.5-63.5 %, fixed carbon 29.0 to 31.0 % and moisture 0.5-0.6 % (by wt.).
3. The process as claimed in claim 1, wherein the cross-linked polymeric additive comprises C-C-O group of phenolic moieties, aromatic C=C groups and cross-linking moiety (aliphatic and aromatic -CH group).
4. The process as claimed in claim 1, wherein the synthesizing the cross-linked polymeric additive comprising steps of:
dissolving low QI based coal tar in N, N-dimethyl formamide (DMF) solvent with heating at 80-90 °C for 2-3 hrs;
adding a 2.5–3.5 % (by wt.) conc. sulfuric acid into the homogeneous solution of coal tar and the DMF solvent to create a reaction mixture, the DMF solvent being configured to stable the material in the liquid phase;
mixing 10-15% (by wt.%) of formaldehyde into the reaction mixture at the temperature of 80-90 °C for 2-3 hours;
adding a specified amount of cross-linker hexamine 1.25 to 1.75% (by wt.) into the reaction mixture while maintaining the temperature at 80-90 °C for 2-3 hours, so as to convert the reaction mixture into a cross-linked polymeric additive;
distilling out water formed during the conversion of the cross-linked polymeric additive; and
cooling the cross-linked polymeric additive to room temperature.
5. The process as claimed in claim 4, wherein the cross-linked polymeric additive comprises 75-80 % (by wt.) coal tar.
6. The process as claimed in claim 1, wherein the coal blend is prepared from different types of coal including semi-soft coal, hard coking coal, and non-coking coal.
7. The process as claimed in claim 6, wherein the coal blend comprises non coking coal 10-15 %, hard coking coal is 35-45 %, and semi soft is 50-55 % (by wt).
8. The process as claimed in claim 1, wherein the cross-linked polymeric additive enables to accommodate 10-15 % non-coking coal in the coal blend.
9. The process as claimed in claim 1, wherein the coal tar is a low moisture coal tar having moisture 1-2% (by wt.).
10. The process as claimed in claim 1, wherein the coal tar has the low QI of 1-2.5 %.
11. A cross-linked polymeric additive to be used in a coal blend, comprising:
solid content 61.5-63.5 %, fixed carbon 29.0 to 31.0 %, moisture 0.5-0.6 % (by wt.), specific gravity 1.16 – 1.20 (at 25 °C) and viscosity 1800-2000 cP (at 25 °C).
12. The cross-linked polymeric additive as claimed in claim 9, wherein the cross-linked polymeric additive comprises C-C-O group of phenolic moieties, aromatic C=C groups and cross-linking moiety (aliphatic and aromatic -CH group).
13. The cross-linked polymeric additive as claimed in claim 9, wherein the cross-linked polymeric additive has model structure

14. The cross-linked polymeric additive as claimed in claim 9, wherein the cross-linked polymeric additive comprises 75-80 % (by wt.) coal tar.