FIELD OF INVENTION
[001] The present subject matter described herein, relates to a method of gasification of high ash
Indian coal in a high Pressure Oxy-Blown Bubbling Fluidized Bed Gasifier.
BACKGROUND AND PRIOR ART OF THE INVENTION
[002] Gasification is a process of converting carbonaceous fuels into combustible gases also called synthesis gas (syngas) through partial oxidation of the fuel. Syngas composition majorly consists of CO, CO2, CH4, H2 and N2 with minor constituents of H2S, NH3, COS and HCN. There are three broad types of gasifiers which have to be selected based on fuel characteristics and end application requirement namely Moving or Fixed Bed Gasifier, Fluidized bed Gasifier and Entrained type Gasifier. Fluidized bed Gasifier is the most suitable type for gasification of high ash Indian coals.
[003] In fluidized bed gasifier, bed of coal particles are transformed into fluid like state with fluidizing medium also called as gasifying agent. There are different types of fluidization regimes depending on particle size of coal, fluidizing medium properties and operating velocity. Bubbling fluidization bed is one type of fluidization where bottom section of the reactor contains dense bed of solids which are uniformly mixed termed as reactor zone and upper section contains lean bed of solids distributed over height of the section termed as freeboard zone. There are two types of gasification process based on mode of oxygen supply to gasifier. They are Air blown and Oxy-Blown Gasification processes. If oxygen is supplied through air it is called as air blown gasification and if oxygen is supplied as pure oxygen it is called as Oxy-blown gasification. In addition to oxygen in fluidization medium, CO2 and steam are admitted to moderate gasification temperature and maintain fluidization velocity. In case of air blown gasification, nitrogen in air will take care of controlling gasification temperature and fluidization velocity. In case of oxy-blown gasification combination of steam and CO2 is used to moderate gasification temperature and fluidization velocity. Air blown gasification process is more suitable for coal to power generation applications like Integrated Gasification Combined Cycle (IGCC) and Oxy-blown gasification is more suitable for coal to chemical applications like Methanol, Hydrogen and Ammonia etc. Maintaining proper

composition of fluidizing medium for specific coal type is very crucial to maintain appropriate operating temperature for generation of desired syngas flow and composition with optimal gasifier performance.
[004] For commercial gasification applications, operating pressure of the gasifier impacts the throughput of the plant. Higher the operating pressure higher the coal throughput which is desired to maximum for commercial plant. Choosing optimal gasifier dimensions with right combination of fluidizing mixture and operating pressure by maximizing coal throughput to meet commercial requirements is important.
[005] Reference may also be made to the following prior arts:
[006] With reference to CN103224813B relates to a pressurized fluidized bed technology for coal gasification and a system thereof, The technological steps include: pressurizing and conveying pulverized coal into a pressurized fluidized bed gasifier, letting the pulverized coal and a gasification agent directly undergo a contact reaction so as to form a dense phase section at the upper part in the gasifier and a dilute phase section at the lower part, decomposing organic matters contained in the reaction generated raw gas by an organic matter decomposer first, then subjecting the raw gas to cyclone dust removal and sending the raw gas into an exhaust heat boiler to cool to 300-350DEG C, then conducting further dust removal by a high temperature filter, bringing the de-dusted raw gas into a washing tower and performing washing to obtain the raw gas with a dust content of less than or equal to 1mg/Nm3, and delivering the raw gas to a downstream apparatus. Invention claims the diameter of gasifier cylindrical shell is 6 to 10 times of gas pipeline diameter. Coal throughput and clarity on fluidizing medium combinations is not specified.
[007] Another prior art WO2020256783A1 relates to a large-scale fluidized bed bio gasifier provided for gasifying bio solids. The bio gasifier includes a reactor vessel with a pipe distributor and at least two fuel feed inlets for feeding bio solids into the reactor vessel at a desired fuel feed rate more than 40 tons per day with an average of about 100 tons per day during steady state operation of the bio gasifier. A fluidized bed in the base of the reactor vessel has a cross-sectional area that is proportional to at least the targeted fuel feed rate such that the superficial velocity of gas is in the range of 0.1 m/s (0.33 ft/s) to 3 m/s (9.84 ft/s). In operation, bio solids are heated to a temperature range between 900°F (482.2°C) and 1600°F (871.1°C). This invention claims the fluidized bed has a diameter of at least 108 inches and the freeboard section has a diameter of at

least 137 inches. A gas distributor that is a pipe distributor comprising: a main air inlet, a center trunk line having lateral air branches; and an array of nozzles located on each of the lateral air branches indicates air-blown gasification envisaged in the invention to gasify bio solids.
[008] Another prior art US5937652A relates to provide an improved method for solid fuel (coal or biomass) utilization by using carbon dioxide for gasification of the fuel. Carbon dioxide extracted from a boiler flue gas stream is recycled for the gasification of the solid fuel. This invention claims the combination of a carbon dioxide coal gasifier and a steam power plant where a steam boiler is fueled with a synthesis gas and char produced by gasification of coal in absence of oxygen using carbon dioxide separated from the boiler flue gas, the combination which comprises; p1 a. a coal fluidized bed gasifier where sufficient carbon dioxide and steam are injected to provide proper fluidization velocity and residence time for the coal to dry, de-volatize, and for carbon in the coal to react with carbon dioxide and steam to produce synthesis gas and solid char products. Maintaining operating temperature in gasifier with CO2 and steam without insulation losses from boiler to Gasification Island is difficult.
[009] CN209957720U relates to a fluidized bed reactor for gasifying high ash, low activity faulty coal includes: the reactor comprises a reactor main body, wherein a gas distribution plate is arranged in the reactor main body and divides the reactor main body into a dense-phase area and a gas chamber; wherein, the gas distribution plate is also provided with a gasification agent jet pipe and a slag discharge pipe; one position of the dense-phase zone is provided with a pulverized coal inlet.
[0010] Another prior art US20100040510A1 relates to systems and methods for converting biomass into syngas using a pressurized multi-stage progressively expanding fluidized bed gasifier to eliminate or reduce the formation of methane, volatiles such as BTX, and tars. The gasifier may include a reactive stage that may receive a biomass feed through a feed line and oxygen through an oxygen feed line. The gasifier may also include a fluidized bed section that may be configured to receive the reaction products from the first stage, mix them and perform fluidized bed activity. A gasifier may also have a disengagement section that may be configured to separate fluidized media and particulate matter from syngas product. A gasification system may also include oxy-blown catalytic auto thermal reactor and a cryogenic air separation unit. This invention claims

fluidized bed gasifier with multi stages with expanding diameter suitable for biomass gasification with oxy-blown gasification process.
[0011] None of the above prior arts can fulfil the requirements of the invention for which it is designed. Hence, the present invention has been introduced.
OBJECTS OF THE INVENTION
[0012] It is therefore the object of the invention to overcome the aforementioned and other drawbacks in prior art.
[0013] The principal objective of the present invention is to provide for a method of gasification of high ash Indian coals using mixture of oxygen, carbon dioxide and steam as fluidizing medium suitable for commercial applications in a high Pressure Oxy-Blown Bubbling Fluidized Bed Gasifier.
[0014] Another objective of the present invention is to provide for an oxy-blown gasification process with fluidizing medium having combination of CO2 and steam at high pressure.
[0015] Another objective of the present invention is to provide for a syngas composition range for different combination of fluidizing medium.
[0016] These and other objects and advantages of the present subject matter would be apparent to a person skilled in the art after consideration of the following detailed description taken into consideration with accompanying drawings in which preferred embodiments of the present subject matter are illustrated.
SUMMARY OF THE INVENTION
[0017] One or more drawbacks of the conventional technology based on existing apparatus and processes are overcome, and additional advantages are provided through a novel method of gasification of high ash Indian coal in a high Pressure Oxy-Blown Bubbling Fluidized Bed Gasifier.

[0018] Additional features and advantages are realized through the technicalities of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered to be a part of the claimed disclosure.
[0019] In accordance with an embodiment of the present subject matter, a method of gasification of high ash Indian Coal in a high pressure oxy-blown fluidized bed coal gasifier comprising the steps of crushing of coal, sieving of crushed coal, transporting the crushed and sieved coal from coal feeding system comprising of locks, hoppers and feeders to fluidized bed coal gasifier above distributor and feeding of fluidizing medium into the fluidized bed coal gasifier (5,6) through a transport line below the distributor (3), wherein coal feed particle diameter is in the range 0.5mm to 6mm, wherein the operating pressure is in the range of 25-30 bar, wherein operating velocity is in the range of 0.6m/s to 0.8m/s, wherein operating temperature is in the range of 950-1000 oC and wherein coal flow rate is maintained in the range of 2000-2650 TPD.
[0020] In another embodiment of the present subject matter, the fluidizing mixture includes CO2 blown mixture and steam blown mixture.
[0021] In another embodiment of the present subject matter, the high pressure oxy-blown fluidized bed coal gasifier is maintained at 3.65m.
[0022] In another embodiment of the present subject matter, the surface temperature of the fluidized bed coal gasifier is maintained below 50 oC.
[0023] In another embodiment of the present subject matter, the CO2 blown mixture the CO2/Coal mass ratio is in the range of 1.5 to 1.6, Steam/Coal mass ratio is in the range of 0.25 to 0.35 and Oxygen/Coal mass ratio is in the range of 0.55 to 0.65.
[0024] In another embodiment of the present subject matter, the steam blown mixture the Steam/Coal mass ratio is in the range of 0.9 to 1.0 and Oxygen/Coal mass ratio is in the range of 0.6 to 0.7.
[0025] In another embodiment of the present subject matter, the ash content of the coal in the range of 30% to 45%.

[0026] 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.
[0027] 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 ACCOMPANYING DRAWINGS
[0028] It is to be noted, however, that the appended drawings illustrate only typical embodiments of the present subject matter, and are therefore not to be considered for limiting of its scope, for the invention may admit to other equally effective embodiments. The detailed description is described with reference to the accompanying figures. In the figures, 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 or methods or structure in accordance with embodiments of the present subject matter are now described, by way of example, and with reference to the accompanying figures, in which:
[0029] Figure 1 illustrates a schematic view of a high-pressure oxy-blown fluidized bed gasifier in accordance with an embodiment of the present disclosure;
DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS
[0030] The detailed description of various exemplary embodiments of the disclosure is described herein with reference to the accompanying drawings. It should be noted that the embodiments are described herein in such details as to clearly communicate the disclosure. However, the amount of details provided herein are not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the present disclosure as defined by the appended claims.

[0031] It is also to be understood that various arrangements may be devised that, although not explicitly described or shown herein, embody the principles of the present disclosure. Moreover, all statements herein reciting principles, aspects, and embodiments of the present disclosure, as well as specific examples, are intended to encompass equivalents thereof.
[0032] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a",” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes” and/or “including,” when used herein, specify the presence of stated features, integers, steps, operations, elements and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and/or groups thereof.
[0033] It should also be noted that in some alternative implementations, the functions/acts noted may occur out of the order noted in the figures. For example, two figures shown in succession may, in fact, be executed concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved.
[0034] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example embodiments belong. It will be further understood that terms, e.g., those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
[0035] The present disclosure discloses a novel method of gasification of high ash Indian Coal in a high pressure oxy-blown fluidized bed coal gasifier comprising the steps of crushing of coal, sieving of crushed coal, transporting the crushed and sieved coal from coal feeding system comprising of locks, hoppers and feeders to fluidized bed coal gasifier above distributor and feeding of fluidizing medium into the fluidized bed coal gasifier (5,6) through a transport line below the distributor (3), wherein coal feed particle diameter is in the range 0.5mm to 6mm, wherein the operating pressure is in the range of 25-30 bar, wherein operating velocity is in the range of 0.6m/s to 0.8m/s, wherein operating temperature is in the range of 950-1000 oC and wherein coal flow rate is maintained in the range of 2000-2650 TPD.

TECHNICAL ADVANTAGES:
[0036] Present invention consists of operating gasifier in oxy-blown mode with 2 variants of fluidizing mixture which caters to wide variety of coal to chemical applications. Syngas composition generated from gasifier is flexible to meet downstream requirements. Capacity of the plant caters to commercial scale gasifier to generate chemicals like methanol and ammonium nitrate. Any further additional capacity requirement can be met with multiples of the capacity proposed in present invention.
[0037] These and other advantages of the present subject matter would be described in greater detail with reference to the following figures. It should be noted that the description merely illustrates the principles of the present subject matter. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described herein, embody the principles of the present subject matter and are included within its scope.
[0038] With reference to Figure 1, the present disclosure discloses a method of gasification of high ash Indian coal in a high Pressure Oxy-Blown Bubbling Fluidized Bed Gasifier.
[0039] Coal (101) after crushing & sieving is transported through conveying system into coal feeding system comprising of locks, hoppers and feeders. Coal is admitted through coal transport line into fluidized bed coal gasifier at a location which is above distributor (103). Fluidizing medium consisting of a mixture of oxygen, CO2 & steam (102) is admitted through fluidizing medium transport line at a location which is below distributor (103) into fluidized bed coal gasifier (105, 106). Coal and fluidizing medium admitted into gasifier undergoes gasification process for a provided operating conditions such as temperature, pressure, coal flow rate, oxygen, CO2 & steam flow rates, bottom ash flow rates and bed inventory & residence time.
[0040] Synthesis gas (Syngas) consisting mainly of CO, CO2, CH4, H2, H2O and N2 is generated through coal gasification process along with the ash & unburnt carbon formation. Syngas and fine ash particles are removed from the top of the gasifier exit line (107) and sent to cyclone (108) for removing fly ash particles.
[0041] Unburnt and fly ash particles (109) are recycled back into gasifier to improve carbon conversion through non-mechanical valve. Syngas from cyclone top is sent to gas clean up system consisting of series of heat exchangers to reduce syngas temperatures, particulates separators to

remove fine ash particles in the syngas and absorbers to remove contaminants such as NH3, H2S & alkalis from syngas to ensure the syngas composition & condition meets the end use application requirement. Coarser ash particles and unburnt carbon are removed from ash discharge line (104) into ash discharge system consisting of extractors and locks & receivers.
[0042] Constant desired operating temperature is maintained by regulating oxygen to coal flow rate ratio and constant bed inventory is maintained by regulating bottom ash flow rate. Bubbling fluidized bed condition is maintained by admitting sufficient fluidizing medium flow rate into fluidized bed coal gasifier. The present invention proposes a device and method for high pressure fluidized bed gasification of high ash Indian coals using mixture of oxygen, carbon dioxide and steam as fluidizing medium suitable for commercial applications.
[0043] The average coal feed particle diameter of 1.2 mm with range from 0.5 mm to 6 mm is fed into gasifier. Coal particle reduces size after entering into gasifier based on pilot plant experimental experience, average bed particle diameter of 0.6 mm was observed.
[0044] Operating pressure of 30 bar was chosen based on coal feeding and ash extraction systems availability. In oxy-blown gasification process, CO2 and steam are added with oxygen to regulate operating temperature and to maintain sufficient operating velocity.
[0045] Various pilot plants experiments were conducted to study the effect CO2 and steam composition along with oxygen on gasifier performance. Two combinations of fluidizing mixture are possible. They are CO2 blown and steam blown gasification.
[0046] In CO2 blown gasification, CO2 is the major constituent in fluidizing medium and in steam blown gasification steam is the major constituent. Operating velocity in the range of 0.6 m/s to 0.8 m/s is finalized based on average bed particle diameter, operating pressure and fluidizing medium.
[0047] Gasifier inner diameter of 3.65 m was finalized based on manufacturing capability and also considering refractory & insulation layer thickness to maintain gasifier surface temperature less than 50 oC. Coal throughput of 2650 TPD was estimated for selected gasifier diameter based on gasifier modelling and simulation for a specific fluidizing medium mixture combination which was optimized based on experimental data.

[0048] As the gasification process progress, volumetric flow rate of gaseous medium at the bottom of gasifier increases due to addition of moisture, volatiles and carbon from coal which leads to increase of operating velocity. When operating velocity exceeds the design velocity range, elutriation of bed particle takes place. In order to reduce the particle elutriation, gasifier diameter is increased to 4.3 m diameter at the top of reactor zone.
[0049] Gasifier section is enlarged from 3.65 m diameter at bottom to 4.3 m at top. Gasifier section above reactor zone is called as freeboard zone where sufficient height has to be provided to reduce the solid particles entrainment out of the gasifier. Diameter of 4.3 m is maintained throughout the freeboard section and height of 19.5 m is required to minimise the particles entrainment.
[0050] In CO2 blown gasification process, fluidizing mixture consists of CO2, Oxygen and steam. For maintaining operating temperature in the range of 950 to 1000 oC, CO2/Coal mass ratio of 1.6, Steam/Coal mass ratio of 0.25 and Oxygen/Coal mass ratio of 0.55 have to be maintained at operating pressure of 30 bar. Syngas composition generated through CO2 blown gasification have CO in the range of 25-30 %, CO2 in the range of 40-50%, CH4 in the range of 0.7-0.9 %, H2 in the range of 8.5-10.5 % and H20 in the range of 15-20 %. In this mode, CO2 in syngas is captured in the downstream process and recycled back to Gasification Island to mix with fluidizing medium. The net CO2 in kg per kg of Coal generated in this process is 0.32.
[0051] In steam blown gasification process, fluidizing mixture consists of Oxygen and steam. For maintaining operating temperature in the range of 950 to 1000 oC, Steam/Coal mass ratio of 0.9 and Oxygen/Coal mass ratio of 0.6 have to be maintained at operating pressure of 30 bar. Syngas composition generated through steam blown gasification have CO in the range of 17.5-21.5 %, CO2 in the range of 13.5-16.5%, CH4 in the range of 0.55-0.65 %, H2 in the range of 15.5-19.5 % and H20 in the range of 42-52 %. The net CO2 in kg per kg of Coal generated in this process is 0.65.
[0052] High pressure oxy-blown fluidized bed gasifier proposed in this invention is capable to process 2650 TPD of high ash Indian coal having ash content in the range of 30 to 45 %. CO2 blown and steam blown gasification process is selected depending on end requirement of syngas.
[0053] Working of invention

[0053] The method of gasification of high ash Indian Coal in a high pressure oxy-blown fluidized bed coal gasifier (105, 106) comprising the steps of crushing of coal; sieving of crushed coal; transporting the crushed and sieved coal from coal feeding system (101) comprising of locks, hoppers and feeders to fluidized bed coal gasifier (105, 106) above distributor (103); and feeding of fluidizing mixture (102) into the fluidized bed coal gasifier (105,106) through a transport line below the distributor (103), wherein coal feed particle diameter is in the range 0.5mm to 6mm, wherein the operating pressure is in the range of 25-30 bar, wherein operating velocity is in the range of 0.6m/s to 0.8m/s, wherein operating temperature is in the range of 950-1000 oC, wherein coal flow rate is maintained in the range of 2000-2650 TPD. The fluidizing mixture (102) includes CO2 blown mixture and steam blown mixture. The inner diameter of the high pressure oxy-blown fluidized bed coal gasifier (105) is maintained at 3.65m. The surface temperature of the fluidized bed coal gasifier (105, 106) is maintained below 50 oC. The CO2 blown mixture (102) the CO2/Coal mass ratio is 1.6, Steam/Coal mass ratio is 0.25 and Oxygen/Coal mass ratio is 0.55 and the steam blown mixture (102) the Steam/Coal mass ratio is 0.9 and Oxygen/Coal mass ratio is 0.6. The ash content of the coal is in the range of 30% to 45%.

TEST RESULT
Process parameters CO2 blown Steam blown
Coal flow rate Kg/hr 110000 110000
CO2 flow rate Kg/hr 175500 0.0
Oxygen flow rate@ 98% purity Kg/hr 60500 65000
Steam flow rate Kg/hr 30000 100000
Operating Temperature Deg C 950 950
Residence time Minutes 22 25
Operating Pressure bar 30 30
Gasifier diameter m 3.65 3.65
Performance parameters

Dry gas composition
CO Vol % 33.18 36.93
CO2 Vol % 53.88 27.94
CH4 Vol % 0.95 1.16
H2 Vol % 11.58 33.02
N2 Vol % 0.28 0.81
H2S Vol % 0.06 0.06
Raw Gas Composition
H2O Vol % 17.4 46.92
CO Vol % 27.40 19.60
CO2 Vol % 44.50 14.83
CH4 Vol % 0.79 0.62
H2 Vol % 9.57 17.53
N2 Vol % 0.23 0.43
H2S Vol % 0.05 0.03
NH3 Vol% 0.04 0.03
COS Vol% 0.02 0.01
carbon conversion % 95.17 95.2
Syn gas yield (total syn gas/coal flow rate) kg/kg 3.02 2.10
cold gas efficiency (wet syn gas LCV basis) % 62.56 61.14

operating velocity m/s 0.67 0.68
Steam/Coal kg/kg 0.27 0.91
Oxygen/Coal kg/kg 0.55 0.59
CO2/Coal kg/kg 1.6 0.0
[0039] Reference Numerals Reference Numeral Description
101 Coal feeding system
102 Fluidizing medium
103 Distributor
104 Bottom Ash
105 Reactor zone section
106 Freeboard section
107 Gasifier exit line
108 Cyclone
109 unburnt carbon and fly ash
110 Syngas,
[0054] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present.

For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.”
[0055] It will be further appreciated that functions or structures of a plurality of components or steps may be combined into a single component or step, or the functions or structures of one-step or component may be split among plural steps or components. The present invention contemplates all of these combinations. Unless stated otherwise, dimensions and geometries of the various structures depicted herein are not intended to be restrictive of the invention, and other dimensions or geometries are possible. In addition, while a feature of the present invention may have been described in the context of only one of the illustrated embodiments, such feature may be combined with one or more other features of other embodiments, for any given application. It will also be appreciated from the above that the fabrication of the unique structures herein and the operation thereof also constitute methods in accordance with the present invention. The present invention also encompasses intermediate and end products resulting from the practice of the methods herein. The use of “comprising” or “including” also contemplates embodiments that “consist essentially of” or “consist of” the recited feature.

[0056] Although embodiments for the present subject matter have been described in language specific to structural features, it is to be understood that the present subject matter is not necessarily limited to the specific features described. Rather, the specific features and methods are disclosed as embodiments for the present subject matter. Numerous modifications and adaptations of the system/component of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations, which fall within the scope of the present subject matter.

We Claim:
1. A method of gasification of high ash Indian Coal in a high pressure oxy-blown fluidized
bed coal gasifier (105, 106) comprising the steps of:
crushing of coal;
sieving of crushed coal;
transporting the crushed and sieved coal from coal feeding system (101) comprising of locks, hoppers and feeders to fluidized bed coal gasifier (105, 106) above distributor (103); and
feeding of fluidizing mixture (102) into the fluidized bed coal gasifier (105,106) through a transport line below the distributor (103),
wherein coal feed particle diameter is in the range 0.5mm to 6mm,
wherein the operating pressure is in the range of 25-30 bar,
wherein operating velocity is in the range of 0.6m/s to 0.8m/s,
wherein operating temperature is in the range of 950-1000 oC,
wherein coal flow rate is maintained in the range of 2000-2650 TPD.
2. The method as claimed in claim 1, wherein the fluidizing mixture (102) includes CO2
blown mixture and steam blown mixture.
3. The method as claimed in claim 1, wherein the inner diameter of the high pressure oxy-
blown fluidized bed coal gasifier (105) is 3.65m.
4. The method as claimed in claims 1 to 3, wherein the surface temperature of the fluidized bed coal gasifier (105, 106) is maintained below 50 oC.
5. The method as claimed in claims 1 to 4, wherein in CO2 blown mixture (102) the CO2/Coal mass ratio is 1.5-1.6, Steam/Coal mass ratio is 0.25-0.35 and Oxygen/Coal mass ratio is 0.55-0.65.
6. The method as claimed in claims 1 to 5, wherein in steam blown mixture (102) the Steam/Coal mass ratio is 0.9-1.0 and Oxygen/Coal mass ratio is 0.6-0.7.

7. The method as claimed in claims 1 to 6, wherein ash content of the coal is in the range of
30% to 45%.