FORM-2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE
Specification
(See Section 10 and Rule 13)
AN INCINERATION METHOD AND APPARATUS FOR NON-FOULING TREATMENT OF SPENT WASH
THERMAX LIMITED
an Indian Company,
ofChinchwad, Pune411 019,
Maharashtra, India
Inventor:
l.BAPAT DILIP WAMAN
2. KULKARNI SAMIR VASUDEO
3. AUTADE PRASAD KISAN
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE NATURE OF THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED

This application is a patent of addition for Indian Patent Application No. 550/MUM/2006 issued on April 07, 2006, the entire contents of which, is specifically incorporated herein by reference.
FIELD OF THE DISCLOSURE
This disclosure relates to the field of waste management. BACKGROUND
Industrial waste like spent washes, needs to be treated before being dispersed into the environment in order to avoid environmental pollution.
Spent wash has a high level of BOD/COD and colour which needs to be brought down by treatment before being discharged to acceptable pollution norms. The spent wash, however, has good calorific value and can be treated by incineration to generate biogas with complete combustion of organics and obtaining steam, typically super heated steam which could be used for other processes in an industrial unit.
When used in fluid bed combustion, as disclosed in 550/MUM/2006, spent wash which has low percentage of ash typically between 5 -20% and alkaline components in the form of sodium, potassium and other salts ranging typically between 5-50%, pose problems like bed agglomeration, fouling of heat transfer surfaces and slagging on combustor walls.
Several attempts have been made to treat spent wash.

US5339774 discloses a fluidized bed steam generation system which assists in passage of solid particulate material from a cyclone separator into the furnace, through a loopseal, assisted by recycled flue gases. The recycled flue gases are passed through the heat recovery section having heat exchange tubes with water circulating therewithin, an air heater and a baghouse. The use of the recycled flue gases decreases the oxygen content which can cause oxidizing or burning of the solid particulate material which results in overheating or agglomeration of the loopseal.
US4414001 discloses a method for thermally decomposing and gasifying either liquid or solid combustible material in a single reactor filled with working medium in a high active fluidization. The reactor is divided into two sections, that is, thermal decomposition and gasification section and combustion and heating section. Thermal decomposing and gasification are performed by way of supplying the combustible raw material into the downwardly travelling working medium and at the same time supplying steam thereinto for generating and maintaining the high active fluidization of the working medium. The produced combustible gas as well as combustion gas is produced in the thermal decomposition and gasification section are removed through gas outlet ports located at the upper end portion of the reactor. Burning and heating are performed by way of supplying air or steam mixture gas of oxygen and steam into the upwardly travelling working medium in the combustion and heating section.
US4013516 teaches an apparatus and a process for the thermal decomposition of organic material by removing water by dehydration. The resultant dehydrated organic waste material is pyrolized within a

temperature range of approximately 700° F. to 1800° F which causes lower molecular weight organic compounds to be distilled off as organic vapors and gases while leaving a residue of char and ash.
US5370067 teaches a method of incinerating solid combustible materials wherein solid combustible materials are dried and burned on a mechanical grate furnace in a reducing atmosphere so as to reduce formation of NOx. The combustion gases, thus produced, are burned in the presence of secondary air in a circulating fluidized bed furnace. A filter is provided to remove fly ash from the flue gases prior to being passed through a boiler wherein the flue gases are cooled. The flue gases are then cleaned in a cleansing area before being evacuated by a stack.
US4555249 discloses a reactor having a design S-shaped gasifying unit wherein solid particles are fed and mixed with a hot recycle reagent. In the gasifying zone, a fluidizing gaseous stream such as carbon dioxide or steam is injected to enhance the flow of the solid particles. A gas fractionating unit and a relatively high pressure solid fuel gasifying unit containing a reagent powder having a significant weight difference in reduced form as compared with the weight of the powder in oxidized form is circulated through the S-shaped gasifying unit during oxidation-reduction chemical processing.
US4511437 discloses a process for continuous rectification of a liquid mixture which is fed into a plurality of distillation columns having successively reduced operating pressures and temperatures from an initial one to a final one. The top vapor distillate from the higher-pressure columns supplies driving heat to the sumps of the next successively lower-pressure

columns. Steam at a temperature of 130° C to 160° C is fed into the sump of the column operated at the highest pressure. Direct steam is generated by indirect heat exchange of water with the top vapor withdrawn from the columns, and the resulting direct steam is fed to the sumps of the next-lower-pressure columns.
US5302246 discloses a method of managing liquid steams in a pulp mill wherein effluents are concentrated and incinerated to produce a residue. A part of the residue is distilled to produce gaseous hydrogen chloride and the remaining residue is passed to the recovery loop. Sulfur containing gases from the non-condensable gas system is combusted to produce gaseous sulfur dioxide, which is then converted to sulfuric acid, to distill the residue. Alternatively, the liquid effluents is concentrated in evaporators and directly passed to a recovery boiler.
DRAWBACKS OF THE PRIOR ART:
The prior art is plagued with several drawbacks such as fouling of heat transfer surfaces of a combustion system, agglomeration of the fluidized bed of the combustion system and slagging on surfaces of the walls of the combustion system by deposition of solid particulate matters present in the flue gas generated by incineration of the spent wash or organic material.
Hence, there was felt a need for a method and a system for overcoming the drawbacks of the prior art.

OBJECTS
Some of the objects of the system of the present disclosure, which at least one embodiment herein satisfies, are as follows:
An object of this disclosure is to completely incinerate spent wash while preventing agglomeration on the fluidized bed of a combustion system.
Another object of the disclosure is to provide a method to prevent fouling of heat transfer surfaces of the combustion system.
Still another object of the present disclosure is to prevent slagging of the walls of the combustion system.
An added object of the disclosure is to provide a method to eliminate slagging on the incinerator walls.
Yet another object of the disclosure is to provide a method to minimize
shutdown of a steam generator on account of fouling.
Another object of the disclosure is to minimize coal blending for steam
generation.
Yet another object of this disclosure is to provide a method to recover the heat generated from incineration of spent wash by generating steam energy.
Further an object of the disclosure is to provide a method to dispose off waste while reducing pollution problem.

Still another object of this disclosure is to provide a method which is provides flexibility in operation and economical in use.
Other objects and advantages of the present disclosure will be more apparent from the following description when read in conjunction with the accompanying figures, which are not intended to limit the scope of the present disclosure.
SUMMARY
The present disclosure enables complete combustion of the spent wash by injecting secondary air and tertiary air. Further, temperature of the flue gas generated by incineration of the spent wash is maintained within predetermined temperature ranges in each of the chambers of the incineration apparatus in accordance with the present disclosure. This prevents agglomeration of the fluidized bed.
The present disclosure further includes a vibrating means for continuously vibrating to tubes, acting as heat transfer surface and associated with each of the chambers. The continuous vibration enables dislodging of particulate matter of the flue gas deposited on the tubes. This prevents slagging of particulate matters on the walls of the incineration apparatus and fouling of the heat transfer surface.
In accordance with the present disclosure there is provided a process for treating spent wash comprising the steps of:
• injecting primary air into a fluidized bed in a first chamber;

• spraying spent wash on the fluidized bed;
• incinerating the spent wash on the fluidized bed in the first chamber at a temperature of 900°C to 1050°C, thereby generating flue gas and subliming the alkaline earth salts;
• injecting secondary air and tertiary air into a second chamber for complete combustion of the spent wash;
• reducing the temperature of the flue gas to a range of 700 °C to 800 °C by transferring radiant heat of the flue gas in the second chamber;
• reducing the temperature of the flue gas to a range of 600°C to 700 °C by transferring radiant heat of the flue gas in a third chamber; and
• reducing the temperature of the flue gas to a range of 150°C to 350°C by transferring heat from the flue gas by convection in a fourth chamber;
• providing vibration to the second chamber, the third chamber and the fourth chamber for dislodging of flue gas deposited therewithin; and
• expelling the flue gas to the atmosphere after cleaning by filtration.
The step of injecting primary air may be preceded by the step of heating the
primary air to a temperature in the range of 100°C to 150°C.
The step of injecting secondary air and tertiary air includes swirling the secondary air and the tertiary air to cause turbulence.

In accordance with an embodiment of the present disclosure, the process for treating spent wash, further includes the steps of:
extracting radiant heat from the flue gas in the second chamber and the third chamber and the convection heat from the flue gas in the fourth chamber by a non-thermic fluid; and
collecting steam generated from the non-thermic fluid for use in a downstream process.
Additionally, steam may be passed through the fourth chamber to extract further heat from the flue gas and convert the steam to superheated steam.
Further, the primary air may be heated by the steam generated by extraction of heat by the non-thermic fluid from the flue gas in the second chamber, the third chamber and the fourth chamber.
In accordance with the present disclosure there may be provided an incineration apparatus for treating spent wash and generating steam by transferring heat from the flue gas to a non-thermic fluid.
In accordance with another aspect of the present disclosure, there is provided an incineration apparatus comprising:
a first chamber having a fluidized bed at an operative bottom zone thereof;
an inlet port for spraying spent wash on the fluidized bed within the first chamber;
a primary air inlet for supplying primary air to the fluidized bed for combustion of the spent wash to release flue gas;

a second chamber adapted to receive flue gas from the first chamber, the second chamber adapted to receive secondary air and tertiary air via a secondary air inlet and a tertiary air inlet respectively;
a third chamber fluidly communicating with the second chamber via a passage provided therebetween;
a fourth chamber in fluid communication with the third chamber;
first radiation tubes surrounding the second chamber for cooling the flue gas flowing through the second chamber;
second radiation tubes surrounding the third chamber for cooling the flue gas flowing through the third chamber;
first convection tubes fitted within the fourth chamber for cooling the flue gases flowing through the fourth chamber between the first convection tubes;
a non-thermic fluid containing means for supplying non-thermic fluid to the first radiation tubes, the second radiation tubes and the first convection tubes; and
a vibrating means adapted to periodically vibrate the first radiation tubes, the second radiation tubes and the first convection tubes.
Additionally, at least one hopper may cooperate with the first chamber, the third chamber and the fourth chamber. The hopper may receive particulates selected from the group consisting of un-burnt carbon, fly ash and ash.
Additionally, at least one pair of second convection tubes may be adapted to receive non-thermic fluid from the non-thermic fluid containing means and

converting the non-thermic fluid flowing therethrough into superheated steam to be supplied to a downstream process. The at least one pair of second convection tube may be periodically vibrated by the vibrating means
The vibrating means may be rotating motorized hammers.
The second chamber and the third chamber may define a hollow structure configured from closely spaced radiation tubes located within an insulated housing.
The apparatus may be adapted to maintain temperature of the flue gas exiting the first chamber, the second chamber, the third chamber and the fourth chamber to be in the range of 900°C to 1050 °C, 700°C to 800°C, 600°C to 700°C and 150°C to 350°C respectively.
Additionally, an air filter may be adapted to extract ash from the flue gas exiting the fourth chamber.
The secondary air inlet and the tertiary air inlet may be positioned to inject air substantially angularly to the outer surface of the second chamber, the primary air inlet.
Additionally, a forced draft fan and at least one damper may supply controlled flow of air via the air inlets.
In accordance with another embodiment of the present disclosure, an air pre-heater is surrounded by conduits communicating steam from the non-thermic fluid containing means. The air preheater may heat the primary air to a predetermined temperature.
The number of the secondary air inlet to the number of the tertiary air inlet may be in the ratio of 3:1.

The flow rates of the air through the primary air inlet, the secondary air inlet and the tertiary air inlet may be in the range of 50% to 70%, 20% to 40% and 5% to 15% respectively. The primary air may be injected at a velocity in the range of 1.5m/sec to 3 m/sec.
The inlet port may spray the spent wash from a height in the range of 2 meters to 8 meters above the fluidized bed and at a mass flow rate in the range of 500 Kg/hr/m2 to 1000 Kg/hr/m2.
The passage may be defined by an opening formed on a common wall separating the second chamber and the third chamber.
The passage may be defined by a duct fluidly communicating the second chamber spaced apart from the third chamber. The duct may be positioned at a predetermined included angle with respect to the second chamber.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
The incineration apparatus for treatment of spent wash by heat recover therefrom for steam generation of the present disclosure will now be described with the help of the accompanying drawings, in which:
Figure 1 illustrates a flow diagram for flow of flue gas in accordance with
the present disclosure;
Figure 2 illustrated a flow diagram for the flow of a non-thermic fluid in
accordance with the present disclosure;
Figure 3 schematically illustrates the incineration apparatus in accordance
with one embodiment of the present disclosure;
Figure 4 schematically illustrates the incineration apparatus in accordance
with another embodiment of the present disclosure; and

Figure 5 schematically illustrates the air and flue gas cycle in the incineration apparatus in accordance with the present disclosure; and Figure 6 schematically illustrates the non-thermic fluid cycle in the incineration apparatus in accordance with the present disclosure; and Figure 7 schematically illustrates fluidized bed of the incineration apparatus shown in Figure 3 and Figure 4; and
Figure 8 schematically illustrates the vibrating means in accordance with the present disclosure.
DETAILED DESCRIPTION
Co-pending patent application number 550/MUM/2006, incorporated herewith by way of reference, being the main patent application with respect to the present application for patent of addition, provides a method for incinerating spent wash in a fluidized bed apparatus and an assembly of chambers in which the temperature of the hot flue gas generated in the fluidized bed chamber is lowered in a sequential manner in the plurality of chambers with the help of circulating non-thermic fluid and at the end of the process obtaining superheated steam as a useful product and relatively cool flue gas which satisfies pollution norms. The method and apparatus disclosed in said co-pending application number 550/MUM/2006, does not entirely address the problem of fouling/ agglomeration / slag elimination due to the tendency of the salts to stick to the surface of the apparatus, contacting the flue gas, when passing through in the liquid phase.
The incineration apparatus for treatment of spent wash by heat recover therefrom for steam generation of the present disclosure will now be

described with reference to the embodiments which do not limit the scope and ambit of the disclosure.
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
In accordance with one aspect of the present disclosure there is provided a process for treating spent wash, illustrated in Figure 1, while preventing agglomeration of particulates in the fluidized bed. The process involves the following steps:
In a first step (101), primary air is injected into a fluidized bed. The primary air is heated prior to being injected into the fluidized bed.
In a second step (102), spent wash containing alkaline earth salts is sprayed on the fluidized bed. The spent wash is incinerated in a first chamber, to release flue gas at a controlled temperature in the range of 900°C to 1050°C. The alkaline earth salts, such as potassium, sodium and calcium, are sublimed at the temperature in the range of 900°C to 1050°C.

In a third step (103), secondary air and tertiary air are injected to mix with the flue gas for complete combustion of the spent wash. The secondary air and tertiary air are injected in a swirling turbulent manner.
In a fourth step (104), temperature of the flue gas in the second chamber is reduced to a range of 700 °C to 800 °C by heat transfer from the flue gas in the second chamber by radiation.
In a fifth step (105), the radiant heat of the flue gas is further extracted in a third chamber thereby reducing the temperature of the flue gas to lie in the range of600°C to 700 °C.
In a sixth step (106), the heat in the flue gas is transferred by convection in a fourth chamber resulting in reduction in the temperature of the flue gas to a range of l50°C to 350°C.
In a seventh step (107), the flue gas is cleansed by filtering the flue gas before being expelled into the environment.
In accordance with another aspect of the present disclosure there is provided a process for producing heated non thermic fluid, illustrated in Figure 2, from a non-thermic fluid circulated by a natural thermo-siphon cycle. The process involves the following steps:
In a first step (201), the non-thermic fluid is introduced through tubes surrounding the second chamber. The non-thermic fluid absorbs heat by radiation between the tubes and the hot flue gas generated by incineration of the spent wash in the fluidized bed.

In a second step (202), the non-thermic fluid is introduced through tubes surrounding the third chamber. The non-thermic fluid absorbs heat by radiation between the tubes and the hot flue gas generated by incineration of the spent wash in the flujdized bed.
In a third step (203), the non-thermic fluid is introduced through tubes fitted within a fourth chamber, wherein heat is transferred by convection from the hot flue gas to the non-thermic fluid flowing through the tubes fitted within the fourth chamber.
In a fourth step (104), non-thermic fluid is converted into superheated steam by absorbing heat from the flue gas flowing through the fourth chamber. The superheated steam so generated is supplied to a downstream process.
In accordance with another aspect of the present disclosure there is provided an incineration apparatus for treatment of spent wash by heat recovery therefrom for steam generation and is schematically illustrated in Figure 3 and Figure 4. The incineration apparatus includes a first chamber (12), a second chamber (14), a third chamber (16) and a fourth chamber (18). Figure 5 schematically illustrates the air and flue gas cycle in the incineration apparatus in accordance with the present disclosure. Figure 6 schematically illustrates the non-thermic fluid cycle in the incineration apparatus in accordance with the present disclosure.
The first chamber (12) includes a feed nozzle (23), illustrated in Figure 3 and Figure 4, for spraying spent wash onto a fluidized bed (11) for combustion within the first chamber (12). Figure 7 illustrates a detailed

view of the first chamber (12) with the fluidized bed (11). The ratio of cross
sectional area of fluidized bed (11) to the first chamber (12) is typically in
the range of 1:1 to 1:2. The spent wash is sprayed at a mass flow rate in the
range of 500 to 1000 Kg/hr/m2, from a height in the range of 2 meters to 8
meters above the fluidized bed (11). Optionally, at least one of coal, peat,
lignite, charcoal, anthracite, wood, sawdust and cellulose waste is added to
the spent wash. The fluidized bed (11), illustrated in details in Figure 4,
consists of a layer of inert materials (23), such as, sand having size in the
range of 1 to 2 mm. The layer of inert materials (23) is fluidized with the
help of heated primary air flowing through a primary air inlet (13a) at a
velocity maintained in the range of 4 to 6 times the minimum fluidization
velocity of the inert materials (21). The velocity of the heated primary air is
maintained in the range of 1.5m/sec to 3 m/sec. The concentrated spent wash
is incinerated on the fluidization bed (11) within the first chamber (12). The
primary air provides the requisite oxygen for incineration of the spent wash.
The spent wash on incineration, results in formation of bottom ash and flue
gas, containing fly ash and unburnt carbon. The flue gas released on
combustion within the first chamber (12) is at a temperature typically in the
range of 900 °C to 1050 °C. At this temperature, the alkaline salts, such as,
potassium, sodium and the like, on account of low melting point, sublime
into gaseous state without passing through the liquid phase. This prevents
agglomeration of the salts either on the fluidized bed (11) or on the walls of
the chambers, as the salts in the gaseous state flows along with the flue gas
through the second chamber (14), the third chamber (16) and the fourth
chamber (18), wherein the sublimed alkaline salts are progressively cooled
to a temperature at which the salts have substantially reduced tendency to
stick to contacting surface and thus, is easily extracted from the flue gas.

The second chamber (14) and the third chamber (16) are configured to form a hollow structure by closely spaced radiation tubes located within an insulated housing. The closely spaced radiation tubes in the second chamber (14) and the third chamber (16) are indicated in Figure 3 and Figure 4 as first radiation tubes (15a) and second radiation tubes (15b) respectively. The second chamber (14) and the third chamber (16) are in fluid communication. In one embodiment of the incineration apparatus, the second chamber (14) and the third chamber (16) are separated by a common wall (19), illustrated in Figure 3, wherein a passage (17a) is formed by an opening defined at the operative top end of the common wall (19) for communicating the flue gas from the second chamber (14) to the third chamber (16). In another embodiment of the incineration apparatus, illustrated in Figure 4, the second chamber (14) and the third chamber (16) are spaced apart and fluidly communicated via a passage (17b) formed by a duct connected between the second chamber (14) and the third chamber (16) for communicating the flue gas therebetween.
The flue gas generated by incineration within the first chamber (12) at a temperature, typically, in the range of 900 °C to 1050 °C, flows into the second chamber (14). The second chamber (14) includes a secondary air inlet (13b) and a tertiary air inlet (13c) for supplying secondary air and tertiary air respectively at a predetermined angle to the outer circumference of the second chamber (14) thereby resulting in swirl formation causing turbulence within the second chamber (14). The secondary air and tertiary air enables complete combustion of the flue has while partially cooling the flue gas passing through the second chamber (14). The number of the

secondary air inlet (13b) to the tertiary air inlet (13c) is typically in the ratio of 3:1. The flow rates of the air injected through the primary air inlet (13a), the secondary air inlet (13b) and the tertiary air inlet (13c) are typically in the range of 50% to 70%, 20% to 40% and 5% to 15% respectively.
The first radiation tubes (15a) surrounding the second chamber (14) fluidly communicates with a non-thermic fluid containing means (22), containing the non-thermic fluid, via headers. The non-thermic fluid circulating within the first radiation tubes (15a) extracts radiant heat from the flue gas flowing through the second chamber (14). This reduces the temperature of the flue gas exiting the second chamber (14), typically within a range of 700 °C to 800 °C.
The flue gas exiting the second chamber (14) flows into the third chamber (16) via the passage (17a) or (17b), defined between the second chamber (14) and the third chamber (16), The flow path of the flue gas from the second chamber (14) to the third chamber (16) via the passage (17a) or (17b), is typically inverted-U shaped. The inverted-U shaped flow path of the flue gas causes a change in direction of flow of the flue gas. The change in direction of the flue gas combined with reduction in temperature thereof, assists removal of fly ash from the flue gas.
The second radiation tubes (15b), surrounding the third chamber (18), fluidly communicate with the non-thermic fluid containing means (22), containing the non-thermic fluid, via headers. The flue gas on flowing into the third chamber (16) dissipates radiant heat to the non-thermic fluid in the second radiation tubes (15b) and is cooled to a temperature typically in the

range of 600 °C to 700 °C. The non-thermic fluid on absorbing heat from the flue gas, is heated and is circulated back into the non-thermic fluid containing means (22) by natural thermo siphon cycle. The flue gas exiting the third chamber (16) at a temperature typically in the range of 600 °C to 700 °C, flows into the fourth chamber (18). The flow of the flue gas from the third chamber (16) to the fourth chamber (18) is typically L-shaped.
The change in direction of the flue gas from the third chamber (16) to the fourth chamber (18) combined with the reduction of temperature, assists removal of fly ash from the flue gas in the third chamber (16). The fourth chamber (18) includes first convection tubes (15c) and second convection tubes (24) fitted therewithin. The first convection tubes (15c) and second convection tubes (24) fluidly communicate with the non-thermic fluid containing means (22) via respective headers. The first convection tubes (15c) are typically made of boiler quality carbon steel while the second convection tubes (24) are, typically, made of alloy steel. The second convection tubes (24) communicate pressurized non-thermic fluid, typically at a pressure in the range of 30 bars to 40 bars, from the non-thermic fluid containing means (22) to a downstream process (25). The pressurized non-thermic fluid entering the fourth chamber (18), extracts heat by convention from the flue gas at 600 °C to 700 °C, and is converted into superheated steam to be supplied to the downstream process (25). Similarly, the flue gas flows over the first convection tubes (15c) through which non-thermic fluid from the non-thermic fluid containing means (22) is circulated. The non-thermic fluid flowing through the first convection tube (15c) extracts heat by convection from the flue gas passing through the third chamber (16) and flows into the non-thermic fluid containing means (22). The flue gas flowing

over the first convection tubes (15c) and the second convection tubes (24) result in maximum extraction of heat from the flue gas on account of increased surface of contact. The flue gas on transferring heat by convention to the non-thermic fluid, within the first convection tubes (15c) and the second convection tubes (24), is reduced to a temperature in the range of 150 °C to 350 °C which is within permissible temperature limit for being dispersed into the atmosphere.
The sequentially reduction in temperature of the flue gas within the second chamber (14), the third chamber (16) and the fourth chamber (IS) results in cooling of the fly ash, un-burnt carbon and ash from the flue gas. The fly ash and the sublimed salts settle within the second chamber (14), the third chamber (16) and the fourth chamber (18) and are collected in associated hoppers (28). The flue gas exiting the fourth chamber (18) at a temperature in the range of 150 °C to 450 °C enters a bag filter (26) which enables further removal of the remaining fly ash, un-burnt carbon and ash from the flue gas. This reduces the quantity of the fly ash, un-burnt carbon and ash in the flue gas within a permissible limit before, being dispersed into the atmosphere through a chimney (30).
The fly ash and salts in the flue gas contacting the surface of the first radiation tubes (15a), the second radiation tubes (15b), the second convection tubes (24) and the first convection tubes (15c), tend to be deposited thereon. In order to prevent agglomeration of the deposited fly ash and salts, the first radiation tubes (15a), the second radiation tubes (15b), the second convection tubes (24) and the first convection tubes (15c) are periodically vibrated by a vibrating means (31), shown in Figure 8. The vibrating means includes a hammer (34), associated with each of the header. The hammer (34) is operated by a motor (32) through a gear box (33). The

frequency of the periodic vibration is controlled by the gear box (33). The hammers (34) periodically strikes the headers associated with each of the first radiation tube (15a), the second radiation tube (15b), the first convection tube (15c) and the second convection tube (24) so as to transmit a periodic vibration thereto. The periodic vibration transmitted to the first radiation tubes (15a), the second radiation tubes (15b), the first convection tubes (15c) and the second convection tubes (24) causes loosening of the fly ash and salts deposited thereon and hence prevents agglomeration.
A controlled flow of air is supplied to the primary air inlet (13a), the secondary air inlet (13b) and the tertiary air inlet (13c) via a forced draft fan and at least one damper. The primary air is communicated to the primary air inlet (13a) through tubes within the air pre-heater (20). Steam from the non-thermic fluid containing means (22) flows into the air pre-heater (20) and heat is transferred from the steam to the primary air which is heated to a predetermined temperature in the range of 100°C to 150°C. The steam on transferring heat to the primary air is converted into condensate which is pumped into the non-thermic fluid containing means (22) as make-up non-thermic fluid (Muw).
The fly ash, un-burnt carbon and ash collected within the first chamber (12) the second chamber (14), the third chamber (16), the fourth chamber (18) and the bag filter (26) are discharged through the hoppers (28).
Thus, the incineration apparatus for combustion of spent wash for generation of superheated steam in accordance with the present disclosure prevents agglomeration of fluidized bed, slagging on walls and tubes associated with the second chamber (14), the third chamber (16) and the convection tubes

within the fourth chamber (16), thereby preventing fouling of the incineration apparatus while ensuring efficient removal of ash from the flue gas.
TECHNICAL ADVANCEMENTS
The technical advancements offered by the present disclosure include the realization of:
• complete incineration of spent wash while preventing agglomeration of fluidized bed in the incinerator chamber;
• preventing slagging on incinerator walls;
• preventing fouling of heat transfer surfaces;
• minimizing coal blending for steam generation;
• utilization of the spent wash for generating steam energy;
• elimination of slagging on incinerator walls;
• minimizing shutdown of a steam generator on account of fouling;
• disposing waste while reducing pollution problem; and
• economical apparatus and method for disposing waste.
Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
The use of the expression "at least" or "at least one" suggests the use of one or more elements or ingredients or quantities, as the use may be in the

embodiment of the disclosure to achieve one or more of the desired objects or results.
The numerical values given of various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher or lower than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the disclosure unless there is a statement in the specification to the contrary.
Wherever a range of values is specified, a value up to 10% below and above the lowest and highest numerical value respectively, of the specified range, is included in the scope of the disclosure.
The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises," "comprising," "including," and "having," are inclusive and therefore 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. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.

Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as "first," "second," and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.
Spatially relative terms, such as "inner," "outer," "beneath", "below", "lower", "above", "upper" and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the example term "below" can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific

embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

We claim:
1. A process for treating spent wash comprising the steps of:
• injecting primary air into a fluidized bed in a first chamber;
• spraying spent wash on the fluidized bed;
• incinerating the spent wash on the fluidized bed in the first chamber at a temperature of 900°C to 1050°C, thereby generating flue gas;
• injecting secondary air and tertiary air into a second chamber for complete combustion of the spent wash;
• reducing the temperature of the flue gas to a range of 700 °C to 800 °C by transferring radiant heat of the flue gas in the second chamber;
• reducing the temperature of the flue gas to a range of 600°C to 700 °C by transferring radiant heat of the flue gas in a third chamber; and
• reducing the temperature of the flue gas to a range of 150°C to 350°C by transferring heat from the flue gas by convection in a fourth chamber;
• providing vibration to the second chamber, the third chamber and the fourth chamber for dislodging particulate matters deposited therewithin; and
• expelling the flue gas to the atmosphere after cleaning by filtration.

2. The process as claimed in claim 1, wherein the step of injecting primary air is preceded by the step of heating the primary air to a temperature in the range of 100°C to 150°C.
3. The process as claimed in claim 1, wherein the step of injecting secondary air and tertiary air includes swirling the secondary air and the tertiary air to cause turbulence.
4. The process for treating spent wash as claimed in claim 1, further
includes the steps of:
extracting radiant heat from the flue gas in the second chamber and the third chamber and the convection heat from the flue gas in the fourth chamber by a non-thermic fluid; and
collecting steam generated from the non-thermic fluid for use in a downstream process.
5. The process for treating spent wash as claimed in claim 1, further includes passing steam through the fourth chamber to extract further heat from the flue gas and convert the steam to superheated steam.
6. The process for treating spent wash as claimed in claim 1, further includes the step of heating the primary air by the steam generated by extraction of heat by the non-thermic fluid from the flue gas in the second chamber, the third chamber and the fourth chamber.
7. An incineration apparatus for treating spent wash by incineration to generate flue gas and generating steam by transferring heat from the flue gas to a non-thermic fluid, as claimed in claim 1.
8. An incineration apparatus comprising:

a first chamber having a fluidized bed at an operative bottom zone thereof;
an inlet port for spraying spent wash on said fluidized bed within said first chamber;
a primary air inlet for supplying primary air to said fluidized bed for combustion of the spent wash to release flue gas;
a second chamber adapted to receive flue gas from said first chamber, said second chamber adapted to receive secondary air and tertiary air via a secondary air inlet and a tertiary air inlet respectively;
a third chamber fluidly communicating with said second chamber via a passage provided therebetween;
a fourth chamber in fluid communication with said third chamber;
first radiation tubes surrounding said second chamber for cooling the flue gas flowing through said second chamber;
second radiation tubes surrounding said third chamber for cooling the flue gas flowing through said third chamber;
first convection tubes fitted within said fourth chamber for cooling the flue gases flowing through said fourth chamber between said first convection tubes;
a non-thermic fluid containing means for supplying non-thermic fluid to said first radiation tubes, said second radiation tubes and said first convection tubes; and

a vibrating means adapted to periodically vibrate said first radiation tubes, said second radiation tubes and said first convection tubes.
9. The apparatus as claimed in claim 8, further comprising at least one hopper cooperating with said first chamber, said third chamber and said fourth chamber, said hopper being adapted to receive particulates selected from the group consisting of un-burnt carbon, fly ash and ash.
10. The apparatus as claimed in claim 8, wherein the apparatus further includes at least one pair of second convection tubes adapted to receive non-thermic fluid from said non-thermic fluid containing means and converting the non-thermic fluid flowing therethrough into superheated steam to be supplied to a downstream process, said at least one pair of second convection tube being adapted to be periodically vibrated by said vibrating means.
11. The apparatus as claimed in claim 8, wherein said vibrating means are rotating motorized hammers.
12. The apparatus as claimed in claim 8, wherein said second chamber and said third chamber defines a hollow structure configured from closely spaced radiation tubes located within an insulated housing.
13. The apparatus as claimed in claim 8, wherein the apparatus is adapted to maintain temperature of the flue gas exiting said first chamber, said second chamber, said third chamber and said fourth chamber to be in the range of 900°C to 1050 °C, 700°C to 800°C, 600°C to 700°C and 150°C to 350°C respectively.

14. The apparatus as claimed in claim 8, further comprising an air filter adapted to extract ash from the flue gas exiting said fourth chamber.
15. The apparatus as claimed in claim 8, wherein said secondary air inlet and said tertiary air inlet are positioned to inject air substantially angularly to the outer surface of said second chamber, said primary air inlet.
16. The apparatus as claimed in claim 8, further includes a forced draft fan and at least one damper to supply controlled flow of air via said air inlets.
17. The apparatus as claimed in claim 8, further comprising an air pre-heater surrounded by conduits communicating steam from said non-thermic fluid containing means, said air preheater adapted to heat said primary air to a predetermined temperature.
18. The apparatus as claimed in claim 8, wherein the number of said secondary air inlet to the number of said tertiary air inlet is in the ratio of 3:1.
19. The apparatus as claimed in claim 8, wherein the flow rates of the air through said primary air inlet, said secondary air inlet and said tertiary air inlet are in the range of 50% to 70%, 20% to 40% and 5% to 15% respectively, said primary air being injected at a velocity in the range of 1.5m/sec to 3 m/sec.
20. The apparatus as claimed in claim 8, wherein said inlet port is adapted to
spray the spent wash from a height in the range of 2 meters to 8 meters
above said fluidized bed and at a mass flow rate in the range of 500
Kg/hr/m2 to 1000 Kg/hr/m2.

21. The apparatus as claimed in claim 8, wherein said passage is defined by an opening formed on a common wall separating said second chamber and said third chamber.
22. The apparatus as claimed in claim 8, wherein said passage is defined by a duct fluidly communicating said second chamber spaced apart from said third chamber, said duct being positioned at a predetermined included angle with respect to said second chamber.