Claims:1. An organic polymer: comprising
Chemical structure

2. The organic polymer as claimed in claim 1, wherein its appearance is black viscous solution.

3. The organic polymer as claimed in claim 1, wherein Viscosity is 50-70 cps.
4. The organic polymer as claimed in claim 1, wherein Viscosity by B-6 cup: 110-130 secs.

5. The organic polymer as claimed in claim 1, wherein pH is 7.0 ± 1.0

6. The organic polymer as claimed in claim 1, wherein Specific Gravity is 1.1-1.2.

7. The organic polymer as claimed in claim 1, wherein it is partly soluble in hot water.

8. A method for making an organic polymer, the method comprising:
mixing water to lignin, followed by formaldehyde and forming a mixture;
heating the mixture gradually to 85-90 Deg C and leaving idle for 45-55 mins;
adding base and idling till it reaches at predetermined temperature of 75-80 Deg C; and
distilling out for removal of excess water and formaldehyde to obtain the organic polymer.

9. The method as claimed in claim 8, wherein Lignin and formaldehyde ratio is 1.2-1.5.

10. The method as claimed in claim 8, wherein the base is sodium hydroxide.

11. The method as claimed in claim 8, wherein the base is 8-10% of the volume of the mixture.
12. A blend for using a non-coking coal (NCC) for metallurgical coke making comprising:
a one or more non-coking coal (NCC) 10-15 wt% with a one or more coking coal (CC) (85-90 wt%) in predetermined ratio; and
an organic polymer with chemical structure
13. The blend as claimed in claim 12, wherein the organic polymer is 0.5-0.7 wt% of the blend.

14. The blend as claimed in claim 12, wherein Coking coal comprises Hard coking coal (HCC) and Mid Coking Coal (MCC) 30-35 wt% and 55 wt% respectively.
15. The blend as claimed in claim 14, wherein HCC have CSN >6 and MCC have CSN 4-6

16. The blend as claimed in claim 12, wherein Non-Coking Coal have CSN <3.

17. The blend as claimed in claim 12, wherein CSN of the blend is 6-7.5.

18. The blend as claimed in claim 12, wherein the CSR of the coke made from the blend is 50.8-54.8.

19. The blend as claimed in claim 12, wherein the CRI of the coke made from the blend is 30.1-31.6.

20. The blend as claimed in claim 12, wherein the fluidity of the blend is 220-243 ddpm.

21. The blend as claimed in claim 12, wherein the organic polymer is added by replacing the coking coal.

Dated this 14th day of July 2020
Signature:
Name: Durgesh Mukharya
To: Of K&S Partners, Bangalore
The Controller of Patents Agent for the Applicant
The Patent Office, at Kolkata IN/PA No. 1541
, Description:TECHNICAL FIELD
The present invention relates to coke making. More particularly it relates to improvement of coking potential of non-coking coal in blend.
BACKGROUND
Coke serves very important purposes in a blast furnace process; it is a fuel, reducing agent and is responsible for the permeability of the charge. Because of the numerous functions of coke in blast furnace, stringent quality parameters of its physical and chemical properties are required to ensure smooth operation of high productivity in modern blast furnaces. As the price of prime coking coal is high and the worldwide reserve of prime coking coal is low, research is going on to develop some alternate carbonaceous material, which can improve the coke quality.
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 fluidic regime. Based on this criterion, the main objective of this project is to develop an organic compound (polymers, macrocycles and small organic molecules) and utilize the organic compound to improve the coking potential of non-coking coal and hence accommodate the non-coking coal in the blend. The high strength of the coke is formed when coals form a soft semi-liquid mass during the heating, which then resolidificates and sticks the particles together. Mechanical strength of the coke is highly affected by the fluidity of plastic state at higher temp. 350-550oC. But the blending of biomass with coal decrease fluidity. Because the raw biomasses decompose in low temperatures and release major part of the volatiles before the plastic stage. So, biomass acts as an inert material that binds the plasticized components of the coal. This results in a considerable decrease in the fluidity of the blend.
As the reserve of prime coking coal is limited in India, many methods for improving the coking potential of poor coking or non-coking coals have been examined as alternatives to importing more expensive, better quality coals. Use of different additives is one of the options in order 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.
The use of blends of coals of different origin and quality is the normal practice in the coke making industry. In addition, other types of carbonaceous materials (additives) [1-3] are also included in the formulation of industrial blends for coke production. Different types of additives can be introduced in the coke oven e.g. non-coking coals such as anthracite and bituminous materials like coal-tar or coal-tar pitch [4-6]. Furthermore, materials from petroleum processing have also been used as additives in coke production. 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. Moreover, pitch addition improves the strength characteristics of the resultant coke made from coals having poor rheological properties [7-8].
Another way of using organic binder is the production of formed coke. Formed coke is, in fact, a reconstituted fuel based on briquetting of coal, char or lignite, whereby the particulate matter is compacted with a suitable binder under pressure. The raw or ‘green’ briquettes so obtained are subjected to oxythermal treatment (curing) and then carbonised with the purpose of reducing the volatiles. The commonly used base materials for production of briquetted coke/formed coke include coal/lignites of different properties, char from low temperature carbonization of coal, coke breeze, or even mixtures of these, and the most common bituminous binders used for making formed coke for industrial purposes are residual products from processing coal tar and petroleum [9].
Phenolic resin is a well-known binder for production of formed coke and has also been used in coke making. Condensation of a phenol and aldehyde provides materials, curable to thermoset phenolic resins [10-13]. Base catalyzed condensation, employing at least about a stoichiometric of aldehyde provides, condensates known as resoles, whereas acid catalyst and deficiency of aldehyde, provides novalacs. The characteristic of both liquid and solid resoles is their heat curability to fully cross-linked and infusible products without the need for an added cross-linking agent. From this stand point, resoles are more descriptively referred to as one-step phenolic resin in contrast to novalacs or two-step resins which do require the addition of a cross-linking agent for the curing process. Curing of resoles to higher molecular weight cross-linked thermoset resins proceeds with generation of heat and is accelerated by acid materials.
In the presence of strongly acidic accelerators of the exothermic reaction and a source of blowing action, liquid resoles cure rapidly to cellular phenolic resins. From the stand point of the commercial application, the most significant resoles are, those derived from phenol itself and formaldehyde [14-15].
Another organic binder used in coke making is different form of plastics [16]. Literature revealed that addition of 2 wt. % plastic waste causes a decrease in the maximum fluidity of the coal developed during thermal heating between 400 to 500 0C. The extent of the reduction being influenced by the initial value of coal fluidity, 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 [17]. The polyolefin, high density polyethylene, low density polyethylene and polypropylene, which show a higher temperature of maximum volatile release, reduce coal fluidity to a lesser extent than the other polymers, polystyrene, polyethylene terephthalate, which are characterized by the presence of aromatic rings in the polymer chain and a loss of volatile matter in the coal pre-plastic stage and in the earlier stages of fluidity development.
About 10 wt. % of plastic wastes polystyrene and polyethylene terephthalate, that have an aromatic group in their structure inhibits the fluidity development of a low-fluid coal, while the high-fluid coal still retains a certain degree of fluidity, except for the blend with poly ethylene terephalate (PET) [18].
Another kind of organic binder is coking plant waste [19]. Every year coking plants produce a considerable quantity of coal-tar sludge from the tar decanter and a carbonaceous pitch-like residue from the distillation column of benzol in the byproducts plants. Sometimes, these waste materials are disposed of in large on-site waste pits. Modifications in coke oven operational conditions, including oven-heating practice, oven-charging procedure, and coal preparation techniques, have minimized the generation of tar decanter sludge, but the problem still remains [20-22]. Methods for the elimination of wastes such us burial, incineration, and bio-decomposition are commonly used, but in the case of coal-tar sludge they are ineffective.
However, the utilization of such materials as plasticizing additives to coking blends, by direct addition or as a binder in briquette manufacture, could be an effective procedure for solving the disposal problem. This alternative use has the advantage that waste materials are utilized in situ in the coking plants. The utilization of caking or plasticizing additives either from coal or petroleum precursors to coal blends for producing metallurgical cokes has been widely investigated by various researchers.
On the basis of the results obtained, a classification of the ability to modify the co-carbonization system of the additives studied can be established as binder coal-tar pitch > impregnating coal-tar pitch > pitch-like residues > residues from the tar decanter > crude coal-tar. Although the wastes studied are not as effective as binder coal-tar pitches, their use as additives for industrial coke making has beneficial effects on the environment and on coke structure and properties [19]. It is well known that pitch, solvent refined coal and coking coal produces various kinds of mesophase at the early stage of carbonization. Stabilisation of the plastic phase present during coal carbonisation has been reported to be connected with its hydrogen transfer and donor abilities.
There are number of patents available on the synthesis of organic binder: CN104531023 (preparation of epoxy resin binder), KR101547492 (polyamide resin binder), WO2015107811 (cellulose derived resin binder) etc. Binders are mostly manufactured for refractory uses (JP5727241), for ferrite sintered compounds (JP2012101279), for metal powder injection molding (JP2003286503).
There does not seem to be any art available on the application of binder for improvement of coking potential. Tata Steel has a patent on different derivatives of phenol-formaldehyde resin which is used to induce the coking potential to non-coking coal (IN201731039496). Tata Steel continuously working on the special compound to improve its properties and to reduce the cost of the organic compound. Recently a patent has been filed for a modified phenolic resin polymer, which enable to use more no-coking coal in the blend (Patent Application No. 201731039496…)
References:
1. A. Grint, H. Marsh, Carbonization and liquid-crystal (mesophase) development-Cocarbonization of a high-volatile caking coal with several petroleum pitches, Fuel, 60 (1981), 513-521.
2. G. Collin, B. Bujnowska, Co-carbonization of pitches with coal mixtures for the production of metallurgical cokes, Carbon, 32 (1994), 547-552.
3. R. Alvarez, M. A. Diez, C. Barriocanal, C. S. Canga, C. S., and J. L. Verduras, Use of waste lubricant oil from steel rolling mills in the coking process, ISSJ International, 38 (1998), 23-27.
4. 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.
5. S. Nomura, K. Kato, T. Nakagawa, I. Komaki, The effect of plastic addition on coal caking properties during carbonization, Fuel, 82 (2003), 1775-1782.
6. M. A. Diez, C. Barriocanal, R. Alvarez, Plastic wastes as modifiers of the thermoplasticity of coal, Energy & Fuels, 19 (2005), 2304-2316.
7. A. B. Grigorova, O. I Zelenskii, Organic Clinkering Additives in Coking Batch: A Review, Coke and Chemistry, 56 (2013), 248–252.
8. R. Barranco, J. Patrick, C. Snape, A. Thompson, Impact of low-cost filler material on coke quality, Fuel, 86 (2007), 2179–2185.
9. Formed coke process, Research and development: Japan Coal Energy Center; and Japan Iron and Steel Federation, 1986.
10. A. Benka, M. Talub, A. Cobana, Phenolic resin binder for the production of metallurgical quality briquettes from coke breeze: Part I, Fuel Processing Technology, 89 (2008), 28-37.
11. Andrew, T.H. and Lees, P., 1999, UK Patent, (GB 2330150).
12. Sameshima, K., Mort, K., and Inoue,T., 2002, US Patent, (US 2002/0016441).
13. Qureshi, S.P. and Chan, C., 1999, US Patent (US 5864003).
14. A. Benka, M. Talub, A. Cobana, Phenolic resin binder for the production of metallurgical quality briquettes from coke breeze: Part II the effect of the type of the basic catalyst used in the resol production on the tensile strength of the formed coke, Fuel Processing Technology, 89 (2008), 38-46.
15. A. Benka, M. Talub, A. Cobana, Phenolic resin binder for the production of metallurgical quality briquettes from coke breeze: Part III the effect of the type of acidic hardeners on the quality of the formed coke and the possibility to avoid the curing stage to produce metallurgical briquettes with enough strength, Fuel Processing Technology, 90 (2009), 971-979.
16. M. Ibrahim, E. Hopkins, M.S. Seehra, Thermal and catalytic degradation of commingled plastics. Fuel Processing Technology, 49 (1996), 65-73.
17. M.A. Diez, C. Barriocanal, R. Alvarez, Plastic wastes as modifiers of the thermoplasticity of coal, Energy Fuels, 19 (2005), 2304-2316.
18. S. Nomura, K. Kato, 2006, The effect of plastic size on coke quality and coking pressure in the co-carbonization of coal/plastic in coke oven, Fuel, 85 (2006), 47- 56.
19. 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 (1988), 981-989.
20. H. Marsh, R.C Neavel, Carbonization and liquid crystal (mesophase) development: A common stage in mechanisms of coal liquefication and of coal blends for coke making, Fuel, 59 (1980), 511-513
21. Y. S. Nagoruyi, V.M. Gulyaev, L.I. Glushchenko, Use of tar containing waste product from by-product coke production in coking charge, Coke and Chemistry, 1 (1993),15-17.
22. N. I. Panchenko, V. M. Gulyaev, L.I. Glushchenko, T.G. Morgui, Coke Chem. 1993, 21-24.
Object of the invention:
An object of the invention is to utilize non-coking in blend for coke making.
Another object of the invention is to develop the blend which gives coke properties post coke making comparable with industrial standards of coke.
Disclosure of the Invention
The present invention provides an organic polymer: comprising chemical structure of

In an embodiment, the appearance of the organic polymer is black viscous solution, with Viscosity of 50-70 cps., Viscosity by B-6 cup: 110-130 secs, pH of 7.0 ± 1.0, and Specific Gravity of 1.1-1.2.
The organic polymer is partly soluble in hot water.
In another embodiment, the invention provides an organic polymer comprising:
mixing water to lignin, followed by formaldehyde and forming a mixture;
heating the mixture gradually to 85-90 Deg C and leaving idle for 45-55 mins;
adding base and idling till it reaches at predetermined temperature of 75-80 Deg C; and
distilling out for removal of excess water and formaldehyde to obtain the organic polymer.
In a preferred embodiment, Lignin and formaldehyde ratio is 1.2-1.5.
The base can be sodium hydroxide.
In an embodiment, the base added is 8-10% of the volume of the mixture.
In another embodiment the invention provides a blend for using a non-coking coal (NCC) for metallurgical coke making comprising:
a one or more non-coking coal (NCC) 10-15 wt% with a one or more coking coal (CC) (85-90 wt%) in predetermined ratio; and
an organic polymer with chemical structure
In an embodiment, the organic polymer is 0.5-0.7 wt% of the blend.
In another embodiment, coking coal comprises Hard coking coal (HCC) and Mid Coking Coal (MCC) 30-35 wt% and 55 wt% respectively.
In another embodiment, HCC have CSN >6 and MCC have CSN 4-6
In yet another embodiment, wherein Non-Coking Coal have CSN <3.
In another embodiment, CSN of the blend is 6-7.5.
In another embodiment, the CSR of the coke made from the blend is 50.8-54.8.
In another embodiment, the CRI of the coke made from the blend is 30.1-31.6.
In another embodiment, fluidity of the blend is 220-243 ddpm.
In another embodiment, the organic polymer is added by replacing the coking coal

Brief Description of the Drawings:
In order that the disclosure may be readily understood and put into practical effect, reference will now be made to exemplary embodiments as illustrated with reference to the accompanying figures. The figures together with a detailed description below, are incorporated in and form part of the specification, and serve to further illustrate the embodiments and explain various principles and advantages, in accordance with the present disclosure where:
Fig. 1 illustrates an organic polymer in accordance with an embodiment of the invention.
Fig. 2 illustrates characterization of the organic polymer of the Fig. 1.
Fig. 3 depicts a method for making the organic polymer of Fig. 1.
Description of Preferred Embodiment
The foregoing has broadly outlined the features and technical advantages of the present disclosure in order that the detailed description of the disclosure that follows may be better understood. Additional features and advantages of the disclosure will be described hereinafter which form the subject of the description of the disclosure. It should also be realized by those skilled in the art that such equivalent products and methods do not depart from the scope of the disclosure. The novel features which are believed to be characteristic of the disclosure, as to method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present disclosure. Further, 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.

Thus, before describing the present invention in detail, it is to be understood that this invention is not limited to particularly exemplified products and process parameters or methods 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.

While the disclosure is susceptible to various modifications and alternative forms, specific embodiment thereof has been shown by way of example(s) and will be described in detail below. It should be understood, however, that it is not intended to limit the disclosure to particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternative, falling within the spirit and the scope of the disclosure. Thus, 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 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 "solvent" may include two or more such solvents.

The terms "preferred" and "preferable" 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", "containing", "involving," and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Further, the terms “comprises”, “comprising”, or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a method that comprises a list of acts does not include only those acts but may include other acts not expressly listed or inherent to such method. In other words, one or more acts in a method proceeded by “comprises… a” does not, without more constraints, preclude the existence of other acts or additional acts.

With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. Various singular/plural permutations may be expressly set forth herein for sake of clarity.

Any discussion of documents, methods, acts, materials, devices, articles and the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.

A detailed description for the purpose of illustrating representative embodiments of the present invention is given below, but these embodiments should not be construed as limiting the present invention.
Shown in FIG. 1, is a lignin formaldehyde based compound (an organic polymer). Following are the properties of the organic polymer
Appearance: black viscous solution
Viscosity: 50-70 cps.
Viscosity by B-6 cup: 110-130 secs.
pH: 7.0 ± 1.0
Specific Gravity is 1.1-1.2.
The organic polymer is partly soluble in hot water.
Shown in FIG. 2 is the FTIR spectrum of the organic polymer with single bond C-O stretching vibrations of -CH2OH group 1125 cm-1. The peaks at 1343 cm-1 is associated with the C–H bending vibration. The emerging peaks at 1445 cm-1 are attributed to -CH2 deformation vibration. An aromatic C=C stretching peak is observed at around 1600 cm-1. The peak at 2925 cm-1 is due to the aliphatic -CH modes. The peaks at 3330 cm-1 is associated with the O–H stretching vibration.
Shown in FIG. 3 is a method (300) for making the organic polymer comprising of following steps:
At Step (304) mixing of water to lignin, followed by formaldehyde to form a mixture is done.
At Step (308) the mixture is heated gradually to 85-90 Deg C and leave it idle for 45-55 mins.
At Step (312) base is added to the mixture and keep it idle till it reaches at predetermined temperature of 75-80 Deg C.
At Step (316) distilling is carried out to remove excess water and formaldehyde to obtain the organic polymer.
The Lignin to formaldehyde ratio as mentioned in Step (304) is 1.2-1.5.
In accordance with an embodiment of the invention the base added at Step (312) is sodium hydroxide. Again, in an embodiment the base is 8-10% of the volume of the mixture.
The synthesis of preparing the organic polymer is shown below:

A blend is now defined using a non-coking coal in metallurgical coke making. The blend comprises of a one or more non-coking coal (NC) and a one or more coking coal (CC) in predetermined ratio with the organic polymer of chemical structure in FIG. 1. The non-coking coal is 10-15 wt% of the blend. The coking coal is 85-90 wt% of the blend.
The coking coal in an embodiment comprises mixture of hard coking coal (HCC) and Mid Coking Coal (MCC).
The HCC have Crucible Swelling Number CSN > 6 and MCC have CSN of 4-6.
The Non-Coking Coal have CSN <3.
The coking coal in an embodiment comprises is 30-35 wt% of hard coking coal (HCC) and the MCC being 55 wt% of the blend.
The blend in an embodiment uses the organic polymer 0.5 to 0.7 wt. % of the blend.
The organic polymer enables the generation of transferable hydrogen (H2) in the specific temperature range during carbonization process. The presence of transferrable hydrogen is essential for making coking coal. In the case of non-coking coal, the transferrable hydrogen is largely consumed during the heating up to start of fluidic temperature, while with a strongly coking coal, this transferrable hydrogen could not be taken up to the same extent. Therefore, in the following heating period from start of fluid¬ zone, enough transferrable hydrogen remains, and it can play a role to stabilize cleaved fragment of coal.
So, the organic polymer can generate hydrogen at the above-mentioned specific temperature range when mixed with blend. Which in turn impart the fluidity to the coal matrix. This give an opportunity to incorporate non-coking coal in the blend.
The Crucible Swelling Number (CSN) of the blend with organic polymer is 6-7.5 and coke strength after reaction (CSR) of the coke with the blend is 50.8-54.8.
The blend with the polymer have fluidity of 200-243 ddpm.
The blend enables the polymer to be added by replacing the HCC coking coal.
Similarly, the Coke reactivity index (CRI) for coke made from the blend is 30.1 to 31.6.
The organic polymer is added by replacing the coking coal.
Experimental Analysis
For the Analysis, different coals have been used for blend preparation. Two types of hard coking coal (HCC), two types of medium coking coal (MCC) and one type of non-coking coal (NCC) used for blending. 5 blends (B1, B2, B3, B4 and B5) are prepared with composition as detailed in Table 1. Based on the properties of different coal a series of blend designed in which polymer percentage has been varied from 0.3 to 1 % and it is optimised around 0.5-0.7 %.
Above 1 %, of the polymer causes gas pressure issue. These blends have been subjected to crucible swelling number (CSN), coke reactivity index (CRI), coke strength after reaction (CSR) test and fluidity
Details of the tests are as follows in Table 1 shown below:
Table 1
Blend B1 B2 B3 B4 B5
Component, % HCC-40, MCC-55, NCCC-5 HCC-35, MCC-55, NCC-10 HCC-35, MCC-55, NCC-10, Polymer-0.7 HCC-30, MCC-55, NCC-15, Polymer- 0.7 HCC-30, MCC-55, NCC-15, Polymer- 0.5
CSR 53.4 48.2 54.8 53.1 50.8
CRI 29.8 33.6 30.1 30.6 31.6
CSN 6.5 5.5 7.5 7 6
Fluidity(ddpm) 257 186 242 243 220
The characterization of individual components is detailed below in Table 2
Table 2
Coal Ash, % db VM, % db Crucible Swelling number Fluidity
HCC 9-16 20-24 7-8 300
MCC 10-18 21-24 4-5.5 70
NCC 9-10 15-17 1-3 0
Carbonization study
A series of carbonization tests were designed in the 7 kg carbolite oven. A number of carbonization tests were conducted in the 7-kg test oven, under stamp charging conditions. The series of carbonization tests were carried to study the influence of the with and without polymer in the coke properties. Water was added to the coal blends to obtain the desired value of moisture content. The coal cake was made inside a cardboard box keeping the bulk density 1150 kg/m3.
Initially test was carried out with base blend (blend 1). Then, the hard-coking coal from the base blend is replaced by further adding non-coking coal. Optimized quantity of polymer has been added 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 h 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). In which 200 g coke of 19-21 mm size is heated in a reaction tube (78 mm diameter X 210 mm length) at 11000C for two hours during which CO2 is passed a 5 l/min. 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 a I drum (127 mm diameter X725 mm length) for 30 min at a speed of 20 rpm. The coke is then screened on a 10-mm sieve and the % of + 10 mm fraction is reported as the coke strength after reaction (CSR).
Carbonization results:
From the Table 1 it is evident that with the addition of the polymer the rheological properties that is fluidity and crucible swelling number has been improved. After characterization carbonization study has been conducted.
Coke strength after reaction (CSR): Blend 1 is like the base blend of coke plant containing around 40 % HCC, 55% MCC and 5% NCC. The CSR (Coke strength after reaction) is coming around 53. Then in Blend 2, 5% HCC is replaced by additional 5% NCC. The CSR comes down to 48. This is expected as we are replacing a good coal (HCC) with a poor coal. In blend 3, blend 2 is repeated with the addition of 0.7 wt.% polymer. The result is encouraging. It gives 54.8 CSR which is similar to base blend. Inspite of having 5% more NCC in blend the CSR is maintained. This is due to the addition of polymer. In blend 4, another 5% of HCC replaced by NCC, so total % of NCC blend is 15%. It is found that with addition of 0.7% polymer the CSR is maintained around 53.1, in acceptable range. Similarly, in blend 5, HCC is kept at 30 wt%, MCC is kept at 55 wt% and NCC is kept at 15 wt% with organic polymer of 0.5 wt%. polymer the CSR is maintained around 50.8, in acceptable range.
Above results indicate that addition of polymer in 0.5-0.7% has potential to improve the coking potential of non-coking coal and to replace around 10% of hard coking coal by poor coal.
Coke reactivity index (CRI): The CRI evaluated for blend 1 is 29.8, blend 2 is 33.6, blend 3 is 30.1, blend 4 is 30.6 and blend 5 is 31.6. This is evident that due to addition of the organic polymer there can be replacement of hard coking coal with non-coking coal and the CRI of coke obtained for blends 3 -5 are industrially acceptable.
Fluidity- In fluidity measurement, fine coal (not pulverised) is heated slowly and as it melts and passes through its plastic range, its fluidity is noted. Results are expressed as maximum fluidity in dial divisions per minute (ddpm). Characteristic temperatures recorded are initial softening temperature, maximum fluidity temperature and resolidification temperature. The plastic range, which is the temperature range during which the coal is in its plastic state, is also important. All coking and caking tests are sensitive to oxidation but the fluidity test is by far the most sensitive. The instrument used for fluidity determination is known as Geiseler Plastometer. Plastometer measures the plastic properties of coal by using of a constantly applied torque on a stirrer, placed on a crucible into which the coal is charged. The ASTM standard (D2639-Plastometer) can be followed for this test. 5 gm sample of blend -0.425 mm particle size is packed around a stirrer in a cylindrical steel crucible (21.5mm ID x 35 mm length). As the blend is heated under prescribed conditions of 30 deg. C, it begins to soften, and the torque weight causes the stirrer to rotate in the sample. As the coal begins to soften and attained fluid state at higher temperature, the stirrer rotates more rapidly up to a maximum. As the temperature continues to raise, the fluidity of coal starts to fall because of resolidification of blend and subsequently the stirrer moves slowly until the blend is resolidified into coke and the stirrer stops. The speed of rotation of the stirrer in terms of dial divisions per minute (ddpm) and the corresponding temperatures is recorded every minute. The temperature at 1 ddpm is taken as initial softening temperature. The temperature at the maximum ddpm is taken as maximum fluid temperature. The solidification temperature is the temperature at which the stirrer movement stops. Maximum fluidity corresponds to the maximum ddpm is to be reported.
The Fluidity in (ddpm) for blends 1-5 evaluated is 257, 186, 149, 243 and 220 respectively. It can established that due to addition of the organic polymer fluidity obtained for the coke blends 3 -5 are industrially acceptable and therefore HCC can be replaced by the Non coking coal.
Crucible swelling number (CSN): Crucible swelling number test has been done by following ASTM D720-91 (2010). In which 1 gm of sample of B1-B5 (-0.212 mm size) is taken in a translucent squat shaped silica crucible and the sample is levelled 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 coke button is compared with a standard chart and accordingly, the crucible swelling number (0 to 9) is assigned to the blend sample.
The CSN evaluated for blend 1 is 6.5, blend 2 is 5.5, blend 3 is 7.5, blend 4 is 7 and blend 5 is 6. This is evident that due to addition of the organic polymer there can be replacement of coking coal with non-coking coal and the CSN properties of coke obtained are industrially acceptable.
While considerable emphasis has been placed herein on the particular features of this disclosure, it will be appreciated that various modifications can be made, and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other modifications in the nature of the disclosure or the preferred embodiments will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.