Description:FORM 2
THE PATENT ACT 1970
(39 OF 1970)
&
The Patent Rules, 2003
COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

1 TITLE OF THE INVENTION :
A METHOD OF PRODUCING COAL FINES BRIQUETTES HAVING HOT STRENGTH SUITABLE FOR PRODUCER GAS PLANT.


2 APPLICANT (S)

Name : JSW STEEL LIMITED.

Nationality : An Indian Company incorporated under the Companies Act, 1956.

Address : JSW CENTRE,
BANDRA KURLA COMPLEX,
BANDRA(EAST),
MUMBAI-400051,
MAHARASHTRA,INDIA.



3 PREAMBLE TO THE DESCRIPTION

COMPLETE

The following specification particularly describes the invention and the manner in which it is to be performed.

FIELD OF THE INVENTION
The present invention relates to coal fine briquettes having hot strength and a method of briquetting of fuel fine of coal, coke, charcoal and other carbonaceous materials in presence of binding agent and other necessary additives, wherein the binding agent of poly acrylic amide, starch, cement, bentonite as the case may be or will be admixed in addition as a further additive. The disclosure specifically relates to methods for binding coal fine particulate solids by pressure briquetting at a normal temperature, and by use of sodium poly acrylic based binder and bentonite. Application of this briquette is to make producer gas through gasification process. Present invention also relates to a method of producing coal briquettes with having hot strength using high fluidity coal in to the mix.
BACKGROUND OF THE INVENTION
In coal mining, processing and handling, about 20% of the total coal mined is in the form of fines consisting of particles smaller than 0.5 mm. These fines have substantial coal content and so are important to make use of them. For the most part, these fines are not directly usable, thereby these solid particulate material (i.e. coal fine, coal dust, even coke breeze from coking plants and coke ovens) have presented storage, handling, and processing challenges. Coal preparation processes also generates fines in the form of aqueous slurries.
These disadvantageously formed coal fines or coal dust during the production process of coal in coal mines and subsequent processing steps at a metallurgical plant represent a significant and unproductive expense for the industry due to the stringent requirements stipulated for the operation of metallurgy industry and in particular Iron and steel making but these Coal fines embodies a considerable source of energy which can be tapped by concocting a method for utilizing the Coal fines for Metallurgical processes. Accordingly, when such Coal fines can be agglomerated into briquette products (coalbriquette) having both the strength durable to handling during storage and transportation and waterproof against rainfall in the outdoor at a reduced cost, the coal productivity is improved. This leads to an effective use of natural resources and also to a great advantage in various points.
Prior attempts at utilization of Coal fines for producing Coal briquettes are known but these efforts for developing Coal briquettes from Coal fines have been largely unsuccessful because they do not withstand either the stringent standards of metallurgical industry or the resulting product can be mechanically unstable, disintegrating or degrading back into small, fine particles during storage and handling .
Other attempts at producing solid forms from the particulate solids may use costly binder materials, such as petroleum pitch, plastic or polymers, and may use costly and complex processing techniques thus the development have not emerged as a cost-effective solution. Water-based materials will reduce the heating value of fuel based solids and produce a formed material which is unstable during outside storage and transport and may disintegrate causing fugitive dust emissions or ground water contamination. Further, previous attempts have utilized binders, including petroleum-based materials, which become tacky and difficult to transport at ambient and elevated temperatures, and may cause contamination and run-off problems when stored outside.
Some of the unsuccessful attempts have been slated hereunder for lucid understanding of present invention and while the present invention is described herein with reference to illustrative embodiments for particular applications, it should be understood that the invention is not limited thereto. Those having ordinary skill in the art and access to the teachings provided herein will recognize additional modifications, applications, and embodiments within the scope thereof and additional fields in which the present invention would be of significant utility.
Thus, the present invention has been described herein with reference to a particular embodiment for a particular application. Those having ordinary skill in the art and access to the present teachings will recognize additional modifications, applications and embodiments within the scope thereof.
US Patent No. 5,916,826 discloses a biomass binder where the binder is obtained by the liquefaction of biomass at a temperature between 4500F and 7000F and a pressure between 200 pounds per square inch (psi) and 3000 pounds per square inch (psi). The binder then is sprayed on coal particles before being mixed at a temperature of 3000F to 4000F.
US Patent Application Publication No. 2009/0235577 teaches a binder derived from biomass and plastic polymers. This process requires careful selection of the polymer source and a temperature between 257°F and 482°F during mixing in order to fluidize the polymers. The high temperatures needed to prepare the binders in the above references add cost and complexity to the manufacture of the briquettes. Use of briquettes containing polymers may require Steel plant or Power plant operators to apply for new permits, since the characteristics of the emissions may become more harmful. Thus, it would be highly desirable to have briquettes that can be manufactured from coal particles and binders at lower temperatures. Furthermore, the briquettes should be able to be burned by Metallurgical furnaces without producing additional new harmful emissions.
PCT publication WO 02/50219 suggests a method for producing a coalbriquette from fine coal, which is applicable to a smelting reduction iron making process. This publication provides a coalbriquette which is produced from fine coal by mixing molasses as a binder and quicklime as a hardener. Since the smelting reduction process is different from a blast furnace process for iron production, there are differences between properties required for the coalbriquette. In the blast furnace process, since the temperature in the upper part of a blast furnace is as low as 200-300 °C, thermal dynamic decrepitation is not specially considered. At this time, the coalbriquette and sintered ore are sequentially charged into the blast furnace, and then slowly descend to the lower part of the blast furnace. Accordingly, the coal briquette for the blast furnace process is required to have high compressive strength. On the contrary, in the smelting reduction process, since the temperature in the upper part of a smelting furnace is as high as about 1000°C, the volatile components of the coalbriquette are volatilized and decrepitated as soon as the coalbriquette is charged into the smelting furnace. Accordingly, thermal decrepitation and thermal dynamic decrepitation, as well as falling strength are important factors required for the coalbriquette for the smelting reduction process. Although prior art coal briquettes satisfy various properties required for the smelting reduction process, e.g., falling strength of 70% or higher, and thermal decrepitation of 70% or higher, they use only fine coal as their raw material.
Various by-products are outputted from ironworks. To recycle the by-products in iron making processes provides economic advantages. The by-products are largely classified into the following four categories: dust, sludge, slag and waste refractory materials. Among them, since the dust and the sludge contain a large amount of Fe or Fe compounds, carbon (C), Ca compounds and Mg compounds, they are recycled as raw materials in ironworks and cement industries. The Fe compounds mainly include iron oxides. However, a large amount of the dust and sludge tends to be buried through their solidification or incinerated without recycling. Accordingly, treatment and recycling of the by-products are gradually becoming important environmental issues. The dust and the sludge are outputted from every process in ironworks. The dust and the sludge contain carbon usable as a heat source and a reducing agent, Fe compounds usable as an iron source, and Ca compounds and Mg compounds usable as additives, etc. Most of dust and sludge particles have a particle size of 1mm or less. The moisture content in the dust and the sludge is largely depended on various processes or properties of the dust and the sludge. Since the dust and the sludge contain a large amount of valuable components, a part of them are recycled. In view of components contained in the sludge and the dust, and properties and secondary pollution thereof, etc., there is a need for a novel method capable of recycling the dust and the sludge in a pig iron making process. Due to its relatively high moisture content and an additional drying step, the sludge is seldom recycled. Accordingly, the recycling of the sludge is very important.
U.S. Pat. No. 3,898,076 (Ranke, 1975) teaches the use of paraffin wax and a vinyl copolymer as a binder to agglomerate briquettes. Solid organic biomass is used as a briquette filler and fly ash coke as a binder in fuel briquettes formed according to U.S. Pat. No. 4,589,887 (Aunsholt, 1986). U.S. Pat. No. 4,597,790 (Matsui et al., 1986) describes agglomerates formed from iron ore fines or iron sand as a filler with cement or granulated blast furnace slag as a binder, U.S. Pat. No. 5,221,290 (Dell, 1993) describes charcoal briquettes bound with an organic binder and a water-swell able steatite clay. U.S. Pat. No. 5,264,007 (Lask, 1993) teaches the agglomeration of caking coke and finely-divided limestone as briquette filler, using pitch and coal as a binder. U.S. Pat. No. 5,431,702 (Schulz, 1995) describes a method for making fuel briquettes using dewatered sewage sludge, and cellulosic waste such as paper as briquette filler mixed with a conventional binder.
But for all the aforementioned Patents, temperature for curing is high which increase the heat requirement, generally in excess of 100.degree. C., as it is must to confer fuel briquettes with adequate strength. The heat curing process provides conventional briquettes with strength and moisture resistance but also adds to the expense of briquette formation. It is desirable to formulate a binder composition which does not require high heat curing for briquette formation, but which still provides adequate strength and meet other requirements posed by metallurgical furnace.
Thus, a heretofore-unaddressed need exists in the industry to address the aforementioned deficiencies and inadequacies.
It is contemplated, however, that the Coal briquette material according to the present invention may show characteristics different from the hereinafter-described, which are provided as an illustration only. People ordinarily working in concerned realm would readily appreciate that the present may perform differently under different furnace conditions and the performance of the present invention may be changed with change in composition of constituents of Coal briquette. Indeed, the present invention is applicable to any Metallurgical furnace capable of producing iron from iron ore therein. As used in this disclosure and the claims, the term “briquette," as used herein, refers to an agglomerate produced by compressing particles under externally applied pressure and may use elevated temperature. There are numerous methods to compress coal particles into briquettes, including but not limited to extruding, ring-rolling, roll pressing, and die pressing.
Additional features and advantages will be set forth in the description which follows, and in part will be apparent to one of ordinary skill in the art from the description, or may be learned by the practice of the teachings herein. Features and advantages of embodiments described herein may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. Features of the embodiments described herein will become more fully apparent from the following description and appended claims.
OBJECT OF THE INVENTION
A major object of the present invention is to make possible the processing of major Coal fine produced during mining and metallurgical processes of coal without encountering troublesome bridging, channeling, agglomeration, or cementing of the moving bed of producer gas generation plant.
Another object is to provide a process to form Coal fines preferably into briquettes, and may be in the form of extrusions, or pellets of adequate structural integrity to withstand the compressive forces and abrasions experienced in a metallurgical furnace of the indicated geometry and size without being crushed or reduced to fines that would tend to obstruct the free and rapid upward movement of gas.
Another object of the present invention is to provide a process with which Coal fines and dusts of any composition can be processed into an appropriate shape and size with the addition of coke fines, additives and binders in a way that it is cost-effective and allows easy handling so that these briquettes can be charged into producer gas plant application.

SUMMARY OF THE INVENTION
The basic aspect of the present invention is directed to a Binder composition for coal briquette formation including with hot strength suitable for producer gas plants comprising selectively:
Name of binder Range of usage, % Preferable %
Poly acrylic amide 0.2-1.0 0.5
Alkaliactivated Bentonite 1-5 3
Corn starch 1-5 3
Ordinary Portland Cement 1-5 2
High carbon Flyash 1-10 5
Coal tar pitch residue 1-5 3

A further aspect of the present invention directed to said binder composition comprising
Inorganic binders including:

LOI, % SiO2,
% Al2O3,
% CaO,
% Fe2O3,
% K2O, % Na2O,
% P2O5,
% SO3,
% MgO,
% MnO,
% TiO2, % Zn,%
Alkaliactivated bentonite 10.28 42.18 23.85 1.83 16.56 0.20 2.26 0.45 0.14 0.90 0.11 1.21 0.021
High carbon Flyash 10.02 41.17 27.27 9.0 7.85 0.83 0.70 0.67 0.34 0.33 0.08 1.50 0.014
Cement 7.51 15.42 4.64 64.83 5.32 0.47 0.44 0.15 0.80 0.33 0.07 0.01 0.01

Organic binder Corn Starch:
Colour White
Moisture,% 5
Grain size Below 150 microns 90%
Shelf life 12 months
Solubility Water soluble
Swellability 20%

Poly acryl amide:
Color White
Moisture,% 2
Grain size Below 150 microns 100%
Shelf life 12 months
Solubility Water soluble
Base material Poly acryl amide

Coal Tar Residue powder:
Moisture, % 1.0
Volatile Matter (%) 29.91
Fixed Carbon (%) 68.78
Ash (%) 1.31
Carbon (%) 91.2
Sulfur (%) 0.55
Hydrogen (%) 3.24
Nitrogen (%) 0.71

A still further aspect of the present invention directed to said binder composition adapted to generate coal briquettes having thermal decrepitation index in the range of 85% to 95% preferably 90% .

A further aspect of the present invention directed to Coal dust briquettes involving the binder as stated above comprising :

high fluidity coal fines 10-30% preferably 20% in the blend which is having fluidity ranges from 10000-30000 ddpm;
metallurgical coke fines 5-20% preferably 10% of below 6mm in size which contains carbon content of more than 80% to enrich the carbon content of the briquette;
said organic and inorganic bindercompostion including poly acrylic amide based binders, starch and bentonite;
coal tar pitch residue 10-30% preferably 20%;
high carbon flyash with alkali content (Na2O+K2O) in ash of 0.5-2.0% preferably 1.0%;
cement of 5-8% preferably 3%as hardening agent for hot strength, along with water 5-12% preferably 8% to increase the wettability and distribution of binder and hardener with the coal fines.

A further aspect of the present invention directed to said Coal dust briquettes wherein said combination of organic and inorganic binders comprising
Name of binder Range of usage, % Preferable %
Poly acrylic amide 0.2-1.0 0.5
Bentonite 1-5 3
Corn starch 1-5 3
Ordinary Portland Cement 1-5 2
High carbon Flyash 1-10 5
Coal tar pitch residue 1-5 3

A still further aspect of the present invention directed to said Coal dust briquettes wherein properties of the coking coal and metallurgical coke used to improve the hot strength of coal briquettes comprising
Coal type High volatile bituminous coking coal Metallurgical coke fines
Volatile matter, % 34.0 5.0
Ash, % 10.0 13.0
Fixed Carbon, % 56.0 82.0
CSN/FSI 7.5 0
Fluidity, ddpm 30000 0

A still further aspect of the present invention directed to said Coal dust briquettes having oval shape with size of length 35mm, width 45mm, thickness of 25mm.

A still further aspect of the present invention directed to said Coal dust briquettes, having properties comprising
cold compression strength (CCS) of 70-110 kg/cm2 preferably 100 kg/cm2;
porosity of 15-35% preferably 20%;
shatter index of 85-95% preferably 90%;
Thermal decrepitation index (TDI) which is a measure of hot strength of 85-95% preferably 90%; and
gross calorific value of more than 3000 kcal/kg, suitable for producer gas plant application.

A still further aspect of the present invention directed to a method of producing coal dust briquettes with hot strength suitable for producer gas plant application as stated above comprising
(i) providing input ingredients in a mixer including coal fines of less than 6mm size comprising
a)high fluidity coal fines 10-30% preferably 20%;
b)metallurgical coke fines 5-20% preferably 10% of below 6mm in size which contains carbon content of more than 80%;
c)combination of organic and inorganic binders including poly acrylic amide based binders, starch and bentonite;
d)coal tar pitch residue 10-30% preferably 20% which is a byproduct of coal tar pitch;
e)high carbon flyash with alkali content (Na2O+K2O) in ash of 0.5-2.0% preferably 1% which acts as binder at high temperature;
f)cement as hardening agent for hot strength 5-8% preferably 3%; and
g)water 5 to 12preferably 8% to increase the wettability and distribution of binder and hardener with the coal fines.
(ii) subjecting said ingredients to mixing;
(iii) feeding said mixed ingredients via a feeding conveyor to roller press ;
(iv) forming briquettes from feed mix in briquetting press with roll gap of 1.0-3.0 mm preferably 1.5mm to obtain green briquettes of oval shape with size of length 35mm, width 45mm, thickness of 25mm having cold crushing strength and hot properties suitable for handling and charging to producer gas plant.

A further aspect of the present invention directed to said method wherein said mixing step comprising parameters including paddle mixer with single shaft contains blades over the shat with speed of 100 -200 rotations per minute (rpm) preferably 150 rpm.

A still further aspect of the present invention directed to said method wherein said step of briquetting in roller press comprising parameters including pillow shapes rolls made of stainless steel with length of 35mm, width 45mm, and thickness of 25mm along with 6 rows of pockets per roll.

A still further aspect of the present invention directed to said method wherein curing of green briquettes comprising natural curing of briquettes from 48-96 hrs preferably 72hrs to remove the moisture present in briquettes below 4%.

Yet another aspect of the present invention directed to a method of producing producer gas using the coal dust briquettes with hot strength as described above, comprising
feeding coal briquettes along with lump coal(above 6mm) through a charging bin at top into a vertical shaft furnace of producer gas plant;
injecting steam mixing with hot air from the bottom of said furnace;
producing the producer gas through gasification process inside the vertical shaft furnace wherein coal briquettes along with lump coal gets gasified at higher temperature of 1000 o C through three zones comprising Combustion zone, reduction zone and distillation zone and discharged through outlet at top;
collecting the ash residue left after gasification process from the bottom of the furnace.

The above stated and other aspects and advantages of the present invention are described hereunder in greater details with reference to the following accompanying illustrative drawings and example.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Fig 1: show the coal fines briquetting process flow sheet.
Fig 2: show the Process flow of using coal briquettes in producer gas plant.
Fig 3: show the shape of coal briquettes produced.
Fig 4: show the Cross section of the coal briquette.

DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO ACCOMPANYING DRAWINGS AND EXAMPLES
Accordingly, there is a need for developing methods capable of agglomerating fine coal into a coalbriquette in an appropriate manner in order to use in metallurgical furnaces.
The present invention has been achieved in consideration of the above-mentioned situation, and the object of providing inexpensive coal briquette having strength as a raw material to be charged in producer gas plant furnace and weather resistance had been accomplished by the present invention.
Thermal decrepitation index (TDI) of coal briquettes
This method covers the technique and the measurement of thermal decrepitation of briquettes under rapidheating conditions. The test relates to the decrepitation occurring due to the pyrolytic process of coalbriquettes only. The test results, together with chemical and physical properties, point out the applicability ofbriquettes for the producer gas plant application. In this method coal briquettes of 1kg after drying is taken and heated at 1050oC in inert atmosphere for 60 minutes and then cooled in nitrogen gas to avoid the carbon loss due to burning. After cooling the weight % of +20mm retained is called thermal decrepitation index of coal briquettes. This index is the measure of high temperature strength of the briquette at high temperature of above 1000oC to resemble the condition inside the producer gas plant.
Coal used in produced gas plant is used as a major fuel source. The present inventions describes the method of producing coal briquettes from fines generated from the lump coal of producer gas plant by using suitable binders, hardeners so that these briquettes can be used back to the PGP plant to recycle the coal fines generated within the system. Coal used in this invention is dried for achieving the moisture below 5% before doing the briquetting.
Reaction equations between Coal, steam at high temperatures (850 -1050 oC) in the PGP plant are mentioned below.
C (Coal)+O2(Steam)?CO2+97 Kilo calories (Energy)…(1)
CO2(Gas)+C (coal)?2CO-38 Kilo calories (Energy)…(2)
According to the invention there is provided a binder composition for use in Coal briquette formation contains combination of organic and inorganic binders of poly acrylic amide based binders, starch, cement, high carbon flyash and bentonite with the following combination.
Table 1: Binder details
Name of binder Range of usage, % Preferable %
Poly acrylic amide 0.2-1.0 0.5
Alkali activated Bentonite 1-5 3
Corn starch 1-5 3
Ordinary Portland Cement 1-5 2
High carbon Flyash 1-10 5
Coal tar pitch residue 1-5 3

All the binders mentioned in table 1 are not used in a single experiment, but used selectively as a combination of 1-2 binders for different coals dust samples as per the test results shown in following table no. 11.

Table 2: Particle size analysis of the coals used
Indian non coking coal fines Indonesian non coking coal fines South African
Non coking coal fines Russian high fluidity coking coal fines
Size Passing %
+20 mm 0.0 0.0 0.0 0
+16 mm 0.2 0.1 0.0 0
+12.5 mm 5.1 0.3 0.2 0
+10 mm 11.3 0.4 0.5 0
+8 mm 0.8 0.1 0.1 0
+6 mm 11.2 2.8 1.8 5.0
+3 mm 16.5 22.7 17.3 7.0
+2 mm 4.3 7.3 6.8 10.0
+1 mm 14.2 24.7 28.2 24.0
+0.5 mm 11.5 14.0 28.4 32.0
-0.5 mm 25.0 27.6 16.8
22.0
High fluidity Coking coal used to improve the high temperature properties of coal briquettes along with cold strength properties.
Table 3: Properties of the coking coal used to improve the hot strength of coal briquettes
Coal type High volatile bituminous coking coal Metallurgical coke fines
Volatile matter, % 34.0 5.0
Ash, % 10.0 13.0
Fixed Carbon, % 56.0 82.0
CSN/FSI 7.5 0
Fluidity, ddpm 30000 0
(Where CSN/FSI & ddpm stands for Crucible Swelling Number/Free Swelling Index & dial divisions per minute, respectively)

Table 4: Proximate analysis of coal fines
SAMPLE ID Moisture (%) VM
(%) Ash (%) FC (%) C (%) S (%) Gross calorific valuve -GCV
( K.cal /kg)
Indonesian coal fines 12.93 41.67 13.61 44.72 55.4 0.320 5585
Indian coal fines 8.90 23.17 41.00 35.83 46.7 0.881 2612
South African coal fines 7.31 22.68 37.47 39.85 49.7 0.875 3408

Characteristics of binders:
Table 5: Inorganic Binder details
LOI, % SiO2,
% Al2O3,
% CaO,
% Fe2O3,
% K2O, % Na2O,
% P2O5,
% SO3,
% MgO,
% MnO,
% TiO2, % Zn,%
Alkali activated bentonite 10.28 42.18 23.85 1.83 16.56 0.20 2.26 0.45 0.14 0.90 0.11 1.21 0.021
High carbon Flyash 10.02 41.17 27.27 9.0 7.85 0.83 0.70 0.67 0.34 0.33 0.08 1.50 0.014
Cement 7.51 15.42 4.64 64.83 5.32 0.47 0.44 0.15 0.80 0.33 0.07 0.01 0.01
Corn starch:
Table 6: organic Binder details (corn starch)
Colour White
Moisture,% 5
Grain size Below 150 microns 90%
Shelf life 12 months
Solubility Waer soluble
Swellability 20%
Poly acryl amide:
Table 7: organic Binder details (Polymer type)
Colour White
Moisture,% 2
Grain size Below 150 microns 100%
Shelf life 12 months
Solubility Water soluble
Base material Poly acryl amide
Coal tar residue addition:
Table 8: Analysis of Coal tar residue

Moisture, % 1.0
Volatile Matter (%) 29.91
Fixed Carbon (%) 68.78
Ash (%) 1.31
Carbon (%) 91.2
Sulfur (%) 0.55
Hydrogen (%) 3.24
Nitrogen (%) 0.71

Table 9: Size analysis of Coal tar pitch residue
Size (mm) Percentage (%) Cumulative Percentage (%)
+10mm 20.66 20.66
+8mm 8.80 29.46
+6.3mm 12.66 42.12
+4mm 13.75 55.87
+2mm 9.35 65.22
+1mm 12.7 77.92
+0.5mm 9.75 87.67
-0.5mm 12.33 100

Table 10: Chemical analysis and CV of coal briquettes
SAMPLE ID Moisture
(%) VM (%) Ash (%) FC (%) C (%) S
(%) GCV
( kilo calorie/kg)
Briquette 1 4.1 23.79 37.47 38.52 49.4 0.843 3361
Briquette 2 4.0 26.14 41.00 32.06 43.5 0.780 2922
Briquette 3 5.93 38.67 11.95 30.43 50.0 0.231 3644
Briquette 4 3.3 25.19 32.95 18.53 33.8 0.538 2589
Briquette 5 2.8 22.81 32.90 20.35 33.1 0.579 2594

Table 11: Properties of the coal briquettes produced with various combination of additives

Sl
No Coal Screen Size Binder
name 72 hrs natural curing Thermal
Decrepitation
Index (TDI),
%(+10mm)
Moisture of briquette,% CCS,
kg/cm2
1 South African -87% <6mm Starch :5%+ water 8% 3.5 76 90.4
2 South African -90% <3mm Starch: 5%+water 5% 4.0 48 75.0
3 South African -88% <3mm Alkali activated bentonite: 2.5%+ Starch :2.5%+ water 7% 4.1 81 85.0
4 South African -92% <3mm Flyash:3%+ water 5% 3.5 25 55.0
5 South African -87% <3mm Corn starch-5%+water 8% 4.8 110 95.0
6 South African -93.5% <3mm Polyacrylamide-0.5%+water 6% 5.3 40 61.0
7 Indonesian -89% <3mm Corn starch-5%+water 6% 5.8 52 77.0
8 Indonesian -83% <3mm Corn starch: 3%+
Bentonite 2%+ water 12% 6.4 48 73.0
9 Indonesian -87% <3mm Sodium silicate: 8%+
Hydrated lime-2%+water 3% 4.2 10 15.0
10 Indonesian -89% <3mm Cement: 2.0%, Flyash:5.0%+water 4% 3.8 28 41.0
11 Indian coal -85% <6mm Coal tar pitch residue powder-5%+
Corn starch-3%+ water 7% 4.0 78 81.9
12 Indonesian coal 75%+
Mill scale 15% <6mm Corn starch: 5%+water 5% 5.8 64 84.0
13 Indian coal 71%+
Millscale 20% <6mm Corn starch-4%+water 5% 4.0 93 80.5
14 Indian coal 73%+
Millscale 20% <6mm Polyacrylamide 1.0%+water 6% 3.6 63 84.0
15 Indian coal 70%+
Millscale 20% <6mm Corn starch: 2.0%, Bentonite 3%+ water 5% 3.8 68 77.0
16 Indian coal 71%+
Millscale 20% <6mm Corn starch4%+water 5% 4.2 75 80.0
17 Indian coal 72%+high fluidity coking coal10% + coal tar residue 5% <6mm Alkali activated bentonite: 2.5%+ Starch 2.5%+water 8% 2.8 105 90.0
18 South African coal -62%+coking coal20% + coal tar residue 5% <6mm Alkali activated bentonite: 2.5%+ corn starch :2.5%+water 8% 3.0 98 95.0
19 Indonesian coal fines -75%+coking coal10% + coal tar residue 5% <6mm Alkali activated bentonite: 2.5%+ Starch :2.5%+water 5% 2.5 102 89.0
20 Indonesian coal fines -62%+coking coal10% +metallurgical coke fines10% +coal tar residue5% <6mm Corn starch 3%+ Ordinary Portland cement3% +water 7% 1.5 85 90.0

Figure 1 describes the method of producing coal fines briquettes [109] using coal fines of below 6mm size [101] for better granulometry and compaction to make the briquettes of oval shape with size of length 35mm, width 45mm, thickness of 25mm. Intense mixer [105] is used for mixing the coal fines, binder [102], hardener [103] along with water [104] to increase the wettability and distribution of binder and hardener with the coal fines. Mixed material will be discharged into the feeder [106] followed by briquetting using pillow shaped roller press [107] using hydraulic pressure using variable frequency drive [108]. The details of part numbers shown in Fig 1 are as follows:
Number Description
101 Coal fines (below 6mm size)
102 binder
103 Hardener
104 water
105 Intense mixer
106 Feeder
107 Briquetting press
108 Variable frequency drive
109 Produced coal briquettes

Figure 2 describes the method of using produced coal briquettes [109] for producing the producer gas [115] through gasification process inside the vertical shaft furnace. Steam mixing with hot air [114] will be injected from the bottom of the furnace. Coal briquettes along with lump coal [117] gets gasified at higher temperature of 1000 o C by forming three zone which are Combustion zone [111], reduction zone [112] and distillation zone [113] . The residue left after gasification process will be collected from the bottom of the furnace.The details of part numbers shown in Fig 2 are as follows:
Number Description
110 Coal briquettes charging bin
111 Combustion zone
112 Reduction zone
113 Distillation zone
114 Air +steam
115 Producer gas
116 Ash residue
117 Lump coal (above 6mm)

Figure 3 describes the coal briquette produced using coal fines sample of below 6mm particle size using binders and hardeners and additives described in the invention.

Figure 4 describes the cross section of the briquette where fully packed with carbonaceous materials mentioned in the present invention including coking coal, coke fines, coal tar pitch residue, binders & hardeners.
, Claims:We Claim:

1. Binder composition for coal briquette formation including with hot strength suitable for producer gas plants comprising selectively:

Name of binder Range of usage, % Preferable %
Poly acrylic amide 0.2-1.0 0.5
Alkaliactivated Bentonite 1-5 3
Corn starch 1-5 3
Ordinary Portland Cement 1-5 2
High carbon Flyash 1-10 5
Coal tar pitch residue 1-5 3

2. The binder composition as claimed in claim 1 comprising

Inorganic binders including:

LOI, % SiO2,
% Al2O3,
% CaO,
% Fe2O3,
% K2O, % Na2O,
% P2O5,
% SO3,
% MgO,
% MnO,
% TiO2, % Zn,%
Alkaliactivated bentonite 10.28 42.18 23.85 1.83 16.56 0.20 2.26 0.45 0.14 0.90 0.11 1.21 0.021
High carbon Flyash 10.02 41.17 27.27 9.0 7.85 0.83 0.70 0.67 0.34 0.33 0.08 1.50 0.014
Cement 7.51 15.42 4.64 64.83 5.32 0.47 0.44 0.15 0.80 0.33 0.07 0.01 0.01

Organic binder Corn Starch :
Colour White
Moisture,% 5
Grain size Below 150 microns 90%
Shelf life 12 months
Solubility Waer soluble
Swellability 20%

Poly acrylamide:
Colour White
Moisture,% 2
Grain size Below 150 microns 100%
Shelf life 12 months
Solubility Water soluble
Base material Poly acryl amide

Coal Tar Residue:
Moisture, % 1.0
Volatile Matter (%) 29.91
Fixed Carbon (%) 68.78
Ash (%) 1.31
Carbon (%) 91.2
Sulfur (%) 0.55
Hydrogen (%) 3.24
Nitrogen (%) 0.71

3.The binder composition as claimed in anyone of claims 1 or 2 adapted to generate coal briquettes having thermal decrepitation index in the range of 85% to 95% preferably 90%.

4.Coal dust briquettes involving the binder as claimed in anyone of claims 1 to 3 comprising :

high fluidity coal fines 10-30% preferably 20% in the blend which is having fluidity ranges from 10000-30000 ddpm;
metallurgical coke fines 5-20% preferably 10% of below 6mm in size which contains carbon content of more than 80% to enrich the carbon content of the briquette;
said organic and inorganic bindercompostion including poly acrylic amide based binders, starch and bentonite;
coal tar pitch residue 10-30% preferably 20%;
high carbon flyash with alkali content (Na2O+k2o) in ash of 0.5-2.0% preferably 1%;
cement of 5-8% preferably 3%,as hardening agent for hot strength along with water 5 to 12% preferably 8% to increase the wettability and distribution of binder and hardener with the coal fines.

5. The Coal dust briquettes as claimed in claim 4 wherein said combination of organic and inorganic binders comprising

Name of binder Range of usage, % Preferable %
Poly acrylic amide 0.2-1.0 0.5
Alkali activated Bentonite 1-5 3
Corn starch 1-5 3
Ordinary Portland Cement 1-5 2
High carbon Flyash 1-10 5
Coal tar pitch residue 1-5 3

6. Coal dust briquettes as claimed in claim 4 or 5 wherein properties of the coking coal and metallurgical coke used to improve the hot strength of coal briquettes comprising
Coal type High volatile bituminous coking coal Metallurgical coke fines
Volatile matter, % 34.0 5.0
Ash, % 10.0 13.0
Fixed Carbon, % 56.0 82.0
CSN/FSI 7.5 0
Fluidity, ddpm 30000 0

7. Coal dust briquettes as claimed in anyone of claims 4 to 6 having oval shape with size of length 35mm, width 45mm, thickness of 25mm.

8. Coal dust briquettes as claimed in anyone of claims 4 to 7, having properties comprising
cold compression strength (CCS) of 80-150 kg/cm2 preferably 100 kg/cm2;
porosity of 15-35% preferably 20%;
shatter index of 85-95% preferably 90%;
Thermal decrepitation index (TDI) which is a measure of hot strength of 85-95% preferably 90%; and
gross calorific value of more than 3000 kcal/kg, suitable for producer gas plant application.

9. A method of producing coal dust briquettes with hot strength suitable for producer gas plant application as claimed in anyone of claims 4 to 8 comprising
(i) providing input ingredients in a mixer including coal fines of less than 6mm size comprising
a)high fluidity coal fines 10-30% preferably 20%;
b)metallurgical coke fines 5-20% preferably 10% of below 6mm in size which contains carbon content of more than 80%;
c)combination of organic and inorganic binders including poly acrylic amide based binders, starch and bentonite;
d)coal tar pitch residue 10-30% preferably 20% which is a byproduct of coal tar pitch;
e)high carbon flyash with alkali content (Na2O+k2o) in ash of 0.5-2.0% preferably 1% which acts as binder at high temperature;
f)cement as hardening agent for hot strength 5-8% preferably 3%; and
g)water 5 to12%preferably 8%; to increase the wettability and distribution of binder and hardener with the coal fines;
(ii) Subjecting said ingredients to mixing;
(iii) feeding said mixed ingredients via a feeding conveyor to roller press ;
(iv) forming briquettes from feed mix in briquetting press with roll gap of 1.0-3.0 mm preferably 1.5mm to obtain green briquettes of oval shape with size of length 35mm, width 45mm, thickness of 25mm having cold crushing strength and hot properties suitable for handling and charging to producer gas plant.
The method as claimed in claim 9 wherein said mixing step comprising parameters including paddle mixer with single shaft contains blades over the shat with speed of 100 -200 rotations per minute (rpm) preferably 150 rpm
The method as claimed in anyone of claims 9 or 10 wherein said step of briquetting in roller press comprising parameters including pillow shaped rolls made of stainless steel with length of 35mm, width 45mm, and thickness of 25mm along with 6 rows of pockets per roll.

10. The method as claimed in any one of claims 9 to 11 wherein curing of green briquettes comprising natural curing of briquettes from 48-96 hrs preferably 72hrs to remove the moisture present in briquettes below 4%.

11. A method of producing producer gas using the coal dust briquettes with hot strength as claimed in anyone of claims 4 to 8, comprising
feeding coal briquettes along with lump coal(above 6mm) through a charging bin at top into a vertical shaft furnace of producer gas plant;
injecting steam mixing with hot air from the bottom of said furnace;
producing the producer gas through gasification process inside the vertical shaft furnace wherein coal briquettes along with lump coal gets gasified at higher temperature of 1000 o C through three zones comprising Combustion zone, reduction zone and distillation zone and discharged through outlet at top;
collecting the ash residue left after gasification process from the bottom of the furnace.

Dated this the 29th day of September, 2023
Anjan Sen
Of Anjan Sen & Associates
(Applicant’s Agent)
IN/PA-199