WO2021181426A1

WO2021181426A1 - An apparatus and method for conversion of biomass and or refuse derived fuel into charcoal

Info

Publication number: WO2021181426A1
Application number: PCT/IN2021/050253
Authority: WO
Inventors: S.K Sivakumar
Original assignee: Sivakumar S K
Priority date: 2020-03-13
Filing date: 2021-03-13
Publication date: 2021-09-16

Abstract

Embodiments of the present disclosure provide apparatuses (or systems) and method for generating charcoal. The system (100) includes a torrefaction reactor (102) including a rotating drum (202) and a furnace (204). The rotating drum (202) is adapted to receive the in-feed raw material. The furnace (204) includes a plurality of burners (214) configured to heat the in-feed raw material for generating volatiles (216). The volatiles (216) are transmitted to a settling tank (104). The volatiles (216) enable tar (230) to settle in the settling tank (104). An ignition chamber (108) is configured to generate hot flue gas (224) by burning the volatiles (216) and transmit the hot flue gas (224) to the torrefaction reactor (102) to torrefy the in-feed raw material to generate torrefied mass. A cooling tower (116) configured to circulate a fluid to the torrefaction reactor (102) for indirectly cooling the torrefied mass.

Description

AN APPARATUS AND METHOD FOR CONVERSION OF BIOMASS AND OR REFUSE DERIVED FUEL INTO CHARCOAL

TECHNICAL FIELD

[0001] The present disclosure relates to a torrefaction apparatus or systems and, more particularly relates, to apparatus/sy stems and methods for converting a refuse derived fuel (RDF) and/or a lignocellulosic biomass into a carbonaceous fuel, such as charcoal.

BACKGROUND

[0002] In recent times, generation of solid waste (or municipal solid waste (MSW)) and biomass has increased has increased tremendously due to industrialized society and human consumption. The most common solid waste and biomass are agricultural residue, biomass, and refuse derived fuel (RDF) etc. Thus, disposal of the solid waste is the major responsibility to avoid various health hazards. Conventional disposal techniques for disposing the solid waste include dumping the solid waste into large pits in an empty area (land filling), burning the solid waste (thermal decomposition), decomposing using chemicals and the like. However, the conventional disposal techniques for disposing the solid waste have limitations, such as the land becoming useless for a long period of time due to compromise in the soil fertility, degeneration of ground water, release of pollutants, harmful byproducts from chemical reaction, respiratory health diseases, and the like. Further, the disposal of solid waste has become an increasingly difficult task in view of the increasing population in urban and suburban areas and the increasing number of industries generating solid waste.

[0003] Over time, due to technological advancement, torrefaction reactors are devised for converting the solid waste (RDF, biomass, or agriculture residue) into useful fuel (e.g., charcoal). The useful fuel generated from the aforementioned solid waste may have a low calorific value due to lack of control over parameters associated with the conversion of the solid waste to the charcoal. Thus, manual intervention is required for maintaining the parameters at an optimum value for generating charcoal. This makes the process cumbersome, laborious, time consuming and increases the operational cost for generating the charcoal. In addition, the charcoal generated from such techniques tends may be deformed during the process, as the charcoal may subject to blockages or vault formations during its movement in the reactors. Further, as the generated solid waste is increasing, the bulk production of charcoal from the solid waste may not be feasible due to manual control of the parameters and due to the permeability of the raw materials (solid waste) or the charcoal in bulk is irregular.

[0004] Therefore, there is a need for techniques to overcome one or more limitations stated above in addition to providing other technical advantages.

SUMMARY

[0005] Various embodiments of the present disclosure provide systems and methods for producing carbonaceous fuel.

[0006] In an embodiment, a system for torrefaction of an in-feed raw material including at least one of a refuse derived fuel (RDF) and a lignocellulosic biomass is disclosed. The system includes a torrefaction reactor. The torrefaction reactor includes a rotating drum. The rotating drum is configured to rotate about an axis of rotation and adapted to receive the in-feed raw material. The torrefaction reactor includes a first door and a second door configured to be operated between an open position and a closed position. The first door and the second door include a high temperature sealing for creating an air tight environment when the first door and the second door are operated in the closed position upon receiving the in-feed raw material. The torrefaction reactor includes a furnace including a plurality of burners. The plurality of burners is configured to indirectly heat the in-feed raw material within the rotating drum for generating volatiles. The system includes a settling tank coupled to the torrefaction reactor via a central rotating tube positioned at a central portion of the torrefaction reactor. The settling tank includes one or more baffle plates arranged therein. The settling tank is configured to receive the volatiles via the central rotating tube. The volatiles enable tar to settle at a bottom portion of the settling tank as the volatiles traverse within the settling tank. Further the system includes an ignition chamber operatively coupled to the torrefaction reactor. The ignition chamber is configured to generate hot flue gas by burning the volatiles received from the settling tank. The system further includes a heat exchanger operatively coupled to the torrefaction reactor. The heat exchanger is configured to generate hot air from waste flue gas received from the furnace. The hot flue gas and the hot air from the ignition chamber, and the heat exchanger, respectively are transmitted to the furnace for torrefying the in-feed raw material. The system includes a cooling tower fluidically coupled to the torrefaction reactor. The cooling tower is configured to circulate a fluid from the cooling tower into the torrefaction reactor for indirectly cooling the torrefied mass within the torrefaction reactor.

[0007] In another embodiment, a method for torrefaction of in-feed raw material including at least one of a refuse derived fuel (RDF) and a lignocellulosic biomass is disclosed. The method includes receiving the in-feed raw material within a rotating drum of a torrefaction reactor. The method includes operating a plurality of burners associated with a furnace of the torrefaction reactor for indirectly heating the in-feed raw material within the rotating drum to generate volatiles. The method further includes routing the volatiles via central rotating tube positioned at a central portion of the torrefaction reactor to a settling tank. The volatiles passing through the settling tank enable tar to settle at a bottom portion of the settling tank. The method includes routing the volatiles from the settling tank to an ignition chamber for burning the volatiles to generate hot flue gas. Further, the method includes generating hot air by an heat exchanger by receiving air from an outer atmosphere and waste flue gas from the torrefaction reactor under influence of a third blower. The method includes transmitting the hot flue gas, and the hot air into a space between the rotating drum and the furnace for torrefying the in-feed raw material to obtain the torrefied mass. The method includes circulating a fluid from a cooling tower to the torrefaction reactor for indirectly cooling the torrefied mass within the torrefaction reactor.

BRIEF DESCRIPTION OF THE FIGURES

[0008] The following detailed description of illustrative embodiments is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present disclosure, exemplary constructions of the disclosure are shown in the drawings. However, the present disclosure is not limited to a specific device or a tool and instrumentalities disclosed herein. Moreover, those in the art will understand that the drawings are not to scale. Wherever possible, like elements have been indicated by identical numbers:

[0009] FIG. 1 illustrates a simplified block diagram of an apparatus (or system) for torrefying in-feed raw material to generate torrefied mass, in accordance with one embodiment of the present disclosure;

[0010] FIG. 2 illustrates a schematic representation of the system of FIG. 1, depicting a torrefaction reactor for torrefying the in-feed raw material, in accordance with an example embodiment of the present disclosure;

[0011] FIGS. 3A and 3B illustrate a schematic representation of the system of FIG. 1, depicting transmission of a fluid from a cooling tower for indirectly cooling the torrefied mass, in accordance with an example embodiment of the present disclosure;

[0012] FIG. 4 illustrates a block diagram representation of a segregating apparatus along with a shredder for pre-processing the in-feed raw material, in accordance with an example embodiment of the present disclosure; and

[0013] FIG. 5 illustrates a flow diagram of a method for torrefying the in-feed raw material to obtain the torrefied mass, in accordance with an embodiment of the present disclosure.

[0014] The drawings referred to in this description are not to be understood as being drawn to scale except if specifically noted, and such drawings are only exemplary in nature.

DETAILED DESCRIPTION

[0015] In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. It will be apparent, however, to one skilled in the art that the present disclosure can be practiced without these specific details. 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.

[0016] Reference in this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. The appearances of the phrase “in an embodiment” in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Moreover, various features are described which may be exhibited by some embodiments and not by others. Similarly, various requirements are described which may be requirements for some embodiments but not for other embodiments.

[0017] Moreover, although the following description contains many specifics for the purposes of illustration, anyone skilled in the art will appreciate that many variations and/or alterations to said details are within the scope of the present disclosure. Similarly, although many of the features of the present disclosure are described in terms of each other, or in conjunction with each other, one skilled in the art will appreciate that many of these features can be provided independently of other features. Accordingly, this description of the present disclosure is set forth without any loss of generality to, and without imposing limitations upon, the present disclosure.

OVERVIEW

[0018] Various embodiments of the present disclosure provide apparatuses (or systems) and methods for converting a refuse derived fuel (RDF) and/or lignocellulosic biomass into charcoal. In an embodiment, the system includes a torrefaction reactor including a rotating drum disposed within a furnace. The rotating drum is configured to receive the in-feed raw material (e.g., RDF and/or lignocellulosic biomass). The furnace includes a plurality of burners that is configured to heat the in-feed raw material within the rotating drum for generating volatiles. In one example scenario, the in-feed raw material may be subjected to pre-processing based on the type of the in-feed raw material (e.g., loose form, bales form or briquettes). The system further includes a settling tank coupled to the torrefaction reactor. The settling tank includes one or more baffle plates arranged therein. Further, the settling tank is configured to receive the volatiles via central rotating tube of the torrefaction reactor. The volatiles enable tar to settle at a bottom portion of the settling tank, as the volatiles traverse within the settling tank. Further, the system includes an ignition chamber operatively coupled to the torrefaction reactor. The ignition chamber is configured to generate hot flue gas by burning the volatiles received from the settling tank. The hot flue gas is transmitted to the torrefaction reactor to torrefy the in- feed raw material. Further, the system includes a heat exchanger configured to generate hot air by receiving air from an outer atmosphere and waste flue gas from the furnace under the influence of a second blower. The hot air is then transmitted to the torrefaction reactor. The hot air and the hot flue gas transmitted to the torrefaction reactor are configured to indirectly heat the in-feed raw material to generate torrefied mass. The system further includes a control unit. The control unit is configured to monitor a temperature of the rotating drum, upon receiving the hot flue gas and the hot air for torrefying the in-feed raw material. Further, the plurality of burners are deactivated when the temperature of the hot flue gas is determined to be sufficient for torrefying the in-feed raw material. Further, the system includes a cooling tower fluidically coupled to the torrefaction reactor. The cooling tower is configured to circulate a fluid from the cooling tower into the torrefaction reactor via one or more inlets of the torrefaction reactor for indirectly cooling the torrefied mass within the torrefaction reactor. Upon indirectly cooling the torrefied mass, the torrefied mass is discharged from the torrefaction reactor.

[0019] Various embodiments of apparatuses (or systems) and methods for producing carbonaceous fuel, such as charcoal are described with reference to FIG. 1 to FIG. 5.

[0020] FIG. 1 illustrates a simplified block diagram of a system or apparatus (100) for torrefying an in-feed raw material to generate torrefied mass, in accordance with one embodiment of the present disclosure. The system (100) includes a torrefaction reactor (102). The in-feed raw material is subjected to torrefaction process in the torrefaction reactor (102). The in-feed raw material may include, but are not limited to, refuse derived fuel (RDF), lignocellulosic biomass, and the like. The lignocellulosic biomass is a carbonaceous material from plants, or agricultural residues derived from, but not limited to, paddy straws, wheat straws, cotton stalk, maize straws, sugar cane thrash and all other residue materials generated after harvesting the agricultural crops, horticulture, food processing (like com cobs). The RDF corresponds to the combustible fraction of municipal solid waste (MSW) such as, but not limited to, plastics, textiles, wood, rubber, paper, and other carbonaceous waste. The aforementioned in- feed raw material are subjected to torrefaction process in the torrefaction reactor (102). In one implementation, the in-feed raw material is feed into the torrefaction reactor (102) in forms of bales and/or briquettes. In another implementation, the in-feed raw material can be feed into the torrefaction reactor (102) in a loose form (i.e. loose garbage or unsorted MSW). Feeding the loose form in-feed raw material involves segregation of the in-feed raw material which will be explained further in detail.

[0021] In the torrefaction process, the in-feed raw material within the torrefaction reactor (102) are heated up for generating volatiles (interchangeably referred to as 'tor gas'). The volatiles from the torrefaction reactor (102) is allowed to pass into a settling tank (104). The volatiles are then drawn out under influence of a first blower (106) coupled between the settling tank (104) and an ignition chamber (108). The first blower (106) then transmits the tor gas to the ignition chamber (108). The ignition chamber (108) is configured to generate hot flue gas ( e.g thermal fluid) by burning the tor gas received from the torrefaction reactor (102) through the settling tank (104) and transmit the hot flue gas to the torrefaction reactor (102). Further, the system (100) includes a heat exchanger (110) that is configured to generate hot air. The hot flue gas and the hot air transmitted to the torrefaction reactor (102) are configured to torrefy the in- feed raw material for generating the torrefied mass.

[0022] Upon completion of the torrefaction process, the hot flue gas and the hot air from the torrefaction reactor (102) is transmitted to the heat exchanger (110). More specifically, the hot flue gas and the hot air are drawn out from the torrefaction reactor (102) under influence of a third blower (120) coupled between the heat exchanger (110) and a chimney (112). Further, the hot flue gas and the hot air from the heat exchanger (110) can be discharged through the chimney (112) under the influence of the third blower (120). Further, the system (100) includes a cooling tower (116) fluidically coupled to the torrefaction reactor (102). The cooling tower (116) is configured to circulate a fluid to the torrefaction reactor (102) for indirectly cooling the torrefied mass. Upon indirectly cooling the torrefied mass, the fluid may be routed back to the cooling tower (116). Thereafter, the torrefied mass is discharged from the torrefaction reactor (102).

[0023] The system (100) further includes a control unit (118) communicably coupled to the torrefaction reactor (102), the ignition chamber (108), and the heat exchanger (110). The control unit (118) is configured to control one or more operational parameters associated with the system (100) to optimize the torrefaction process for obtaining the torrefied mass with a high calorific value. The control of one or more operational parameters by the control unit (118) are explained with reference to FIGS. 2, 3A and 3B.

[0024] FIG. 2 illustrates a schematic representation of the system (100), depicting the torrefaction reactor (102) for torrefying the in-feed raw material, in accordance with an example embodiment of the present disclosure. As shown in FIG. 2, the torrefaction reactor (102) includes a rotating drum (202) and a furnace (204). The rotating drum (202) is encompassed and/or disposed within the furnace (204). The rotating drum (202) is configured to receive the in- feed raw material (either in the loose form, the bales form or the briquettes). The torrefaction reactor (102) may be divided into two zones, such as a hot zone and a cold zone. The hot zone is indirectly heated by circulating hot flue gas and assists the torrefaction of the in-feed raw material and then the torrefied mass is indirectly cooled in the cold zone by using fluid form the cooling tower (116) which will be explained further in detail. The torrefaction reactor (102) may include spikes (202b) on an inner wall (202a) of the torrefaction reactor (102). The spikes (202b) are configured to de-bale the in-feed raw material when the in-feed raw material is feed into the rotating drum (202) in the bales form.

[0025] The rotating drum (202) with the in-feed raw material is configured to rotate about an axis of rotation ‘Rl’ within the furnace (204). As explained above, the loose form in- feed raw material is subjected to pre-processing, prior to feeding the loose form in-feed materials into the torrefaction reactor (102). The pre-processing is explained later with reference to FIG. 4.

[0026] The rotating drum (202) receives the in-feed raw material via an inlet (206) of the rotating drum (202). As explained above, the rotating drum (202) is configured to rotate in the axis of rotation ‘Rl’ within the furnace (204) during the torrefaction process. More specifically, the rotating drum (202) is coupled to a gear mechanism (208a) ( e.g a gear rack slide) and a pinion (208b). Further, the gear mechanism (208a) and the pinion (208b) are coupled to an actuator (210) (depicted as a drive motor ‘M’) via a control switch (212). The actuator (210) is configured to drive and/or operate the gear mechanism (208) for rotating the rotating drum (202) about the axis of rotation ‘Rl’. In other words, the actuator (210) drivingly engages with the gear mechanism (208) for rotating the rotating drum (202) about the axis of rotation ‘Rl’. Further, the rotation of the rotating drum (202) can be controlled by the control switch (212) by adjusting the speed of a rotor associated with the actuator (210). In an embodiment, the rotation of the rotating drum (202) may be controlled by the control unit (118). Further, the torrefaction reactor (102) includes a pair of support rings (234). Moreover, one support ring of the pair of support rings (234) includes a roller (236). The pair of support rings (234) is configured to support the torrefaction reactor (102). Additionally, the torrefaction reactor (102) includes a first door (240a) and a second door (240b) configured to be operated between an open position and a closed position. The first door (240a) and the second door (240b) include a high temperature sealing for creating an air tight environment when the first door (240a) and the second door (240b) are operated in the closed position upon receiving the in-feed raw material, thus creating positive pressure in the rotating drum (202). Further, the first door (240a), and the second door (240b) may include swinging arms attached to a column on a side of the first door (240a), and the second door (240b) for operating the first door (240a), and the second door (240b) between the open and closed position.

[0027] Further, the furnace (204) includes a plurality of burners (214). The plurality of burners (214) is configured to indirectly heat the in-feed raw material present within the rotating drum (202). To that effect, volatiles or tor gas (referenced as arrows (216)) are generated within the rotating drum (202) by indirectly heating the in-feed raw material. Some non-limiting examples of the burners (214) may be, but are not limited to, a fluidized bed direct hot air generator, fluidized bed indirect hot air generator, a low-oxygen burner or any other conventional heat sources, such as a waste-wood or other burner which is configured to supply heat indirectly to the torrefaction reactor (102). In an embodiment, the single fluidized bed direct hot air generator, fluidized bed indirect hot air generator or any other form of thermal energy (hot air or flue gas) can be passed through a single port and made to encircle around the rotating drum (202) by providing baffles in the furnace (204). As explained above, the positive pressure created within the rotating drum (202) during the torrefaction of the in-feed raw material enables the oxygen to be expelled out from the rotating drum (202) to the outer atmosphere and further restricts the entry of oxygen within the rotating drum (202). It should be noted that the torrefaction is carried out in an oxygen free environment.

[0028] The volatiles (216) from the torrefaction reactor (102) are circulated to the settling tank (104) via a central rotating tube (218) positioned at a central portion (228c) of the torrefaction reactor (102). The central rotating tube (218) includes a bearing less static stuffed box sealing piping arrangement configured to encircle the central rotating tube (218). Further, the central rotating tube (218) may include a SS bellow arrangement (made of stainless steel). The bellow arrangement provides flexibility to the central rotating tube (218) to adjust to the movement of the rotating drum (202), thereby neutralizing the ovality or rotational movement of the rotating drum (202). Further, the central rotating tube (218) may include a base spring plate at the rotating drum (202). The base spring plate is configured to support the central rotating tube (218) to adjust the ovality of the rotating drum (202) as explained above. In an embodiment, the central rotating tube (218) may be configured on both feeding side and discharging side when the volatiles (216) generated is higher than an optimum value.

[0029] The settling tank (104) is configured with one or more baffle plates (222). Tar (230) in the volatiles (216) settles down at a bottom portion (220a) of the settling tank (104), as the volatiles (216) traverse through the settling tank (104). In other words, the volatiles (216) passing through the settling tank (104) from the bottom portion (220a) to a top portion (220b) of the settling tank (104), settles the tar (230) at the bottom portion (220a). More specifically, the volatiles (216) traverses from the bottom portion (220a) to the top portion (220b) and are drawn out of the settling tank (104) by a suction force created by the first blower (106). Further, due to suction force from the first blower (106) and diversion of the volatiles (216) within the settling tank (104) due to the baffle plates (222), the settling of the tar (230) in the settling tank (104) can be optimized. In one implementation, the settled tar (230) is further used in a post-torrefaction process which will be explained further in detail. In another implementation, the settled tar (230) can be periodically collected from the settling tank (104) and used in road laying.

[0030] Thereafter, the volatiles (216) are routed to the ignition chamber (108) by the first blower (106). The ignition chamber (108) is configured to produce fire based on receipt of the volatiles (216). The combustion in the ignition chamber (108) produces hot flue gas (referenced by arrows (224)). Thereafter, the hot flue gas (224) is routed to the furnace (204) via one or more inlet ports (226) (exemplary depicted to be ‘4 inlet ports’) configured at a top portion (228a) of the torrefaction reactor (102). [0031] Further, the heat exchanger (110) coupled to the second blower (114), is configured to generate hot air (referenced by arrows (238)), upon receiving a waste flue gas from the torrefaction reactor (102). The hot air (238) is transmitted to the furnace (204) via an inlet coupled between the heat exchanger (110) and the furnace (204). The inlet between the heat exchanger (110) and the furnace (204) may be of similar configuration to that of the inlet ports (226) (i.e. four ports). The hot flue gas (224) and the hot air (238) are configured to indirectly heat and/or torrefy the in-feed raw material within the rotating drum (202). Further, an inlet temperature of the hot flue gas (224) and the hot air (238) may be adjusted based on a temperature threshold limit. In particular, the heat exchanger (110) receives an optimum amount of cool air drawn from the outer atmosphere by the second blower (114) for adjusting the inlet temperature of the hot flue gas (224). Similarly, the ignition chamber (108) may bum the volatiles (216) to generate the hot flue gas (224) corresponding to the temperature threshold limit. The temperature threshold limit corresponds to a temperature of the hot flue gas (224) and the hot (238) that is sufficient for torrefying the in-feed raw material. Further, regulating the temperature of the hot flue gas (224) depends on a time of residence of the air within the heat exchanger (110). Furthermore, the one or more operations associated with the generation of the hot flue gas (224), and the hot air (238), operating the heat exchanger (110), and the ignition chamber (108), volume of cool air, and speed of the second blower (114) are controlled by the control unit (118).

[0032] The hot flue gas (224) and the hot air (238) may be routed into a space between the furnace (204) and the reactor (202). In some embodiments, the hot flue gas (224) generated from the volatiles (216) may be of about 95% efficiency. In other words, the volatiles (216) are processed by performing one or more steps as explained above and 95% of the volatiles (216) are recirculated to the rotating drum (202) as the hot flue gas (224). The percentage value associated with the recirculation of the volatiles (216) to the rotating drum (202) in the form of the hot flue gas (224) may vary based on feasibility and requirement.

[0033] The hot flue gas (224) and the hot air (238) received at the torrefaction reactor (102) are configured to torrefy the in-feed particles to obtain the torrefied mass. Further, a time of residence of the hot flue gas (224) and the hot air (238) within the torrefaction reactor (102) can be controlled by a control unit, such as the control unit (118). As such, the control unit (118) inherently controls a processing time associated with the torrefaction of the in-feed raw material within the rotating drum (202). In addition, upon receiving the hot flue gas (224) and the hot air (238) that are heated to the temperature threshold limit (or sufficient to heat the furnace (204) to the temperature threshold limit), the burners (214) are deactivated and/or turned off. In this scenario, the hot flue gas (224) and the hot air (238) may be diverted from the ignition chamber (108) and the heat exchanger (110) to the chimney (112) through valves in the torrefaction reactor (102) after a sufficient heating time. The sufficient temperature for torrefying the in -feed raw material may be of about 250 degrees Celsius to 300 degrees Celsius. In some embodiments, the volatiles may be expelled out of the rotating drum (202), so as to maintain the oxygen free environment within the rotating drum (202) as explained above. Thus, it should be understood that, in the torrefaction process, the in-feed raw material is heated to a temperature of about 250 to 350 degrees Celsius in the atmosphere with low oxygen concentrations, so as to eliminate moisture along with a fraction of volatiles from the torrefied mass.

[0034] Further, the hot flue gas (224), and the hot air (238) are passed to the heat exchanger (110) upon completion of the torrefaction process. The hot flue gas (224), and the hot air (238) from the heat exchanger (110) may be exhausted through the chimney (112) under influence of the third blower (120). In an embodiment, the hot flue gas (224) may be subjected to filtration to filter harmful pollutants present in the hot flue gas (224), prior to routing the hot flue gas (224) to the chimney (112), thereby mitigating air pollution and various health hazards caused by the harmful pollutants. Upon obtaining the torrefied mass, the rotating drum (202) is supplied with a fluid from the cooling tower, such as the cooling tower (116) for indirectly cooling the hot torrefied mass. The fluid circulated from the cooling tower (116) may be, but are not limited to, liquid coolant ( e.g water), and cool air. Circulating the fluid (i.e. the liquid coolant or the cool air) from the cooling tower (116) for indirectly cooling the torrefied mass is explained in detail with reference to FIGS. 3A and 3B.

[0035] FIGS. 3A, and 3B illustrate a schematic representation of the system (100) depicting transmission of the fluid from the cooling tower (116) for indirectly cooling the torrefied mass, in accordance with an example embodiment of the present disclosure.

[0036] Referring now to FIG. 3A, the system (100) includes a cooling tower, such as the cooling tower (116). The cooling tower (116) is fluidically coupled to the torrefaction reactor (102) via a pump (302). In this configuration, the cooling tower (116) is configured to transmit a liquid coolant (referenced by arrows (304)) ( e.g water) to the torrefaction reactor (102). The liquid coolant (304) from the cooling tower (116) is pumped by the pump (302) and transmitted to the rotating drum (202) via one or more inlets (306) configured at the top portion (228a) of the torrefaction reactor (102) for indirectly cooling of the torrefied mass. Upon completion of the cooling, the liquid coolant (304) is recirculated back to the cooling tower (116) via a recirculation pump (308). More specifically, the liquid coolant (304) is collected in a collector tank (310) that is positioned proximate to a bottom portion (228b) of the torrefaction reactor (102). The liquid coolant (304) may be circulated to the collector tank (310) via on or more outlets (not shown in FIGS.) of the torrefaction reactor (102). The recirculation pump (308) is configured to pump the liquid coolant collected in the collector tank (310) and transmit the liquid coolant to the cooling tower (116).

[0037] Referring now to FIG. 3B, the cooling tower (116) may be coupled to a heat exchanger, such as the heat exchanger (110). In this scenario, cool air (referenced by arrows (312)) is circulated to the torrefaction reactor (102) for indirectly cooling the torrefied mass. More specifically, the cool air is circulated to the torrefaction reactor (102) via one or more pipes (314) configured at the top portion (228a) and the bottom portion (228b) of the torrefaction reactor (102). In some embodiments, the cool air may be produced by a dessert cooler, chilling plant and the like. Further, the cool air may be exhausted through the chimney (112) passing through the heat exchanger (110), upon indirectly cooling the torrefied mass. In an embodiment, the torrefied mass may be allowed to cool naturally without the aid of liquid coolant or the cool air.

[0038] It should be noted that the torrefying the in-feed raw material by the hot flue gas (224) and indirectly cooling the torrefied mass is carried out within the torrefaction reactor (102). The torrefied mass is then discharged from the torrefaction reactor (102). Then fresh in- feed raw material is feed into the rotating drum (202) and further the process as described above is repeated. The torrefaction reactor (102) may be positioned over a fulcrum (232) (as shown in FIG. 2). This enables the torrefaction reactor (102) to be selectively adjusted (or tilted) to a feeding side and a discharge side while feeding the in-feed raw material and discharging the torrefied mass, respectively. The generation of hot flue gas (224) for indirectly heating the in- feed material, and indirectly cooling the torrefied mass by using the fluid from the cooling tower (116) corresponds to one torrefaction cycle. Further, upon completion of one torrefaction cycle, the system (100) may be turned off by the control unit (118) for discharging the torrefied mass from the torrefaction reactor (102), and to receive a fresh in-feed raw material. It is evident that, generating the torrefied mass by the process as explained above conforms to a batch process or intermittent generation of the torrefied mass, as the system (100) needs to be turned off after each torrefaction cycle. Furthermore, upon discharging the torrefied mass from the torrefaction reactor (102), the torrefied mass may be post-processed for generating pellets. More specifically, the torrefied mass may be subjected to pulverizing to reduce the size of the torrefied mass. Upon pulverizing the torrefied mass may be mixed with binding agents such as, tar (i.e. the tar (230)) for producing pellets.

[0039] Referring now to FIG. 4, a segregating apparatus (400) and a shredder (410) are used for pre-processing the loose garbage, prior to feeding the in-feed raw material to the torrefaction reactor (102). The segregating apparatus (400) includes an integrated bag opener and stone crusher (402), an integrated ballistic and air separator (404), a magnetic separator (406), and an eddy current separator (408). The loose form in-feed raw material are feed into the integrated bag opener and stone crusher (402). The integrated bag opener and stone crusher (402) is configured to crush solid mineral components (such as, stones) present in the loose form in- feed raw material. Then, the loose form in-feed raw material is transmitted to the integrated ballistic and air density separator (404) by using conveyors (not shown in FIGS.).

[0040] The integrated ballistic and magnetic separator (404) includes one or more conveyors, mesh screens of various dimensions. The loose form in-feed raw material are separated based on type of waste materials. Particularly, the ballistic separator separates flat materials and rolling materials present in the loose form in-feed raw material based on the gradability and ballistic movement, respectively. In addition, the size of the loose form in-feed raw material is reduced by passing the loose form in-feed raw material through the mesh screens of various dimensions. More specifically, the integrated ballistic and air density separator (404) is configured to segregate the loose form in-feed raw material to heavy fraction (404a), medium fraction (404c) ( e.g less than 40mm) and light fraction (404b) (40mm size). The medium fraction (404c) is feed into the rotating drum (202). Thereafter, the in-feed materials is transmitted to the air density separator (406). Some non-exhaustive examples of the light fraction (404b) are plastics, tyre, rubber, wood, card board, textile, food waste, paper, sludge biomass and the like. Some non-exhaustive examples of the heavy fraction (404a) are stones, glass, non- ferrous materials and the like. The light fraction (404b) is transmitted to a shredder (410) which will be explained further in detail.

[0041] The heavy fraction (404a) is conveyed to the magnetic separator (406). The magnetic separator (406) is configured to segregate ferrous materials from the heavy fraction (404a). More specifically, the magnetic separator is configured to exert magnetic field which enables the ferrous materials to be separated from the heavy fraction (404a).

[0042] Further, the heavy fraction (404a) is transmitted to the eddy current separator (408). The eddy current separator (408) is configured to remove non-ferrous materials such as, but not limited to, aluminum, copper and the like. In particular, the eddy current separator (408) generates eddy current on the conducting material which receives the heavy fraction (404a). The eddy current exerts an opposing force on the non-ferrous materials, thus enabling the non-ferrous materials to be lifted and thrown out from the heavy fraction (404a). Thereafter, the heavy fraction (404a) is transmitted to the shredder (410). Particularly, at least one combustible material ( e.g coconut shells, pet cans and/or bottles, plastics etc.) present in the heavy fraction (404a) is manually picked by an operator and feed it to the shredder (410). The shredder (410) is configured to convert the light fraction (404b) and the at least one combustible material the heavy fraction (404a) into small fragments (of size less than 25mm). The small fragments of the in-feed material are then feed to the rotating drum (202).

[0043] In an embodiment, the in-feed raw material received from the shredder (410) may be transmitted to a briquettes machine (not shown in FIGS.) for generating briquettes of the loose form in-feed raw material or generating bales. In another embodiment, the loose form in- feed raw material may be subjected to squeezing by a hydraulic squeezer to eliminate moisture content present in the loose form in-feed raw material.

[0044] FIG. 5 illustrates a flow diagram of a method (500) for torrefying the in-feed raw material to obtain the torrefied mass, in accordance with an embodiment of the present disclosure. The method (500) starts at step (502).

[0045] At step (502), the method (500) includes receiving the in-feed raw material within the rotating drum (202) of the torrefaction reactor (102). Further, based on the type of in- feed raw material, the in-feed raw material may be pre-processed as explained with reference to FIG. 4.

[0046] At step (504), the method (500) includes operating the plurality of burners (214) associated with the furnace (204) of the torrefaction reactor (102) for indirectly heating the in-feed raw material within the rotating drum (202) to generate the volatiles (216).

[0047] At step (506), the method (500) includes routing the volatiles (216) via central rotating tube (218) positioned at the central portion (228c) of the torrefaction reactor (102) to a settling tank (104), the volatiles (216) passing through the settling tank (104) enable the tar (230) to settle at the bottom portion (220a) of the settling tank (104).

[0048] At step (508), routing the volatiles (216) from the settling tank (104) to the ignition chamber (108) for indirectly heating the volatiles (216) to generate the hot flue gas (224).

[0049] At step (510), the method (500) includes generating the hot air (238) by the heat exchanger (110) by receiving air from the outer atmosphere and the waste flue gas from the torrefaction reactor (102) under influence of the third blower (120).

[0050] At step (512), the method (500) includes transmitting the hot flue gas (224), and the hot air (238) into the space between the rotating drum (202) and the furnace (204) for torrefying the in-feed raw material to obtain the torrefied mass. At step (514), the method (500) includes circulating the fluid from the cooling tower (116) to the torrefaction reactor (102) for indirectly cooling the torrefied mass within the torrefaction reactor (102).

[0051] Various embodiments of the present disclosure offer multiple advantages. For instance, the present disclosure provides a complete automated solution for utilizing the refuse derived fuel (RDF) and the lignocellulosic biomass that doesn’t involve mass burning, land filling or any environmental impacting aspects. The present disclosure provides a unique apparatus and conversion method which can completely convert the biomass and refuse derived fuel (RDF) into carbon enriched fuel such as charcoal. The uniqueness of the invention is that it provides a closed loop and clean system with built in automated controls which is a commercially viable option.

[0052] Various embodiments of the disclosure, as discussed above, may be practiced with steps and/or operations in a different order, and/or with hardware elements in configurations, which are different than those which, are disclosed. Therefore, although the disclosure has been described based upon these exemplary embodiments, it is noted that certain modifications, variations, and alternative constructions may be apparent and well within the spirit and scope of the disclosure.

[0053] Although various exemplary embodiments of the disclosure are described herein in a language specific to structural features and/or methodological acts, the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as exemplary forms of implementing the claims.

Claims

CLAIMS I/We claim:

1. A system (100) for torrefaction of an in-feed raw material comprising at least one of a refuse derived fuel (RDF) and a lignocellulosic biomass, the system (100) comprising: a torrefaction reactor (102), comprising: a rotating drum (202) configured to rotate about an axis of rotation (Rl) and adapted to receive the in-feed raw material, a first door (240a) and a second door (240b) configured to be operated between an open position and a closed position, the first door (240a) and the second door (240b) comprising a high temperature sealing for creating an air tight environment when the first door (240a) and the second door (240b) are operated in the closed position upon receiving the in-feed raw material, and a furnace (204) comprising a plurality of burners (214) configured to indirectly heat the in-feed raw material within the rotating drum (202) for generating volatiles (216); a settling tank (104) coupled to the torrefaction reactor (102) via a central rotating tube (218) positioned at a central portion (228c) of the torrefaction reactor (102), the settling tank (104) comprising one or more baffle plates (222) arranged therein, the settling tank (104) configured to receive the volatiles (216) via the central rotating tube (218), the volatiles (216) enable tar (230) to settle at a bottom portion (220a) of the settling tank (104) as the volatiles (216) traverse within the settling tank (104); an ignition chamber (108) operatively coupled to the torrefaction reactor (102), the ignition chamber (108) configured to generate hot flue gas (224) by burning the volatiles (216) received from the settling tank (104); a heat exchanger (110) operatively coupled to the torrefaction reactor (102), the heat exchanger (110) configured to generate hot air (238) from waste flue gas received from the furnace (204), wherein the hot flue gas (224) and the hot air (238) from the ignition chamber (108), and the heat exchanger (110), respectively are transmitted to the furnace (204) for torrefying the in-feed raw material; and a cooling tower (116) fluidically coupled to the torrefaction reactor (102), the cooling tower (116) configured to circulate a fluid from the cooling tower (116) into the torrefaction reactor (102) for indirectly cooling the torrefied mass within the torrefaction reactor (102).

2. The system (100) as claimed in claim 1, further comprising a control unit (118) configured to perform at least one of: monitor a temperature of the rotating drum (202), upon receiving the hot flue gas (224) and the hot air (238) for torrefying the in-feed raw material; deactivate the plurality of burners (214) associated with the furnace (204) when the temperature of the hot flue gas (224) and the hot air (238) are determined to be sufficient for torrefying the in-feed raw material to generate the torrefied mass; and divert the hot air (238), and the hot flue gas (224) from the ignition chamber (108) and the heat exchanger (110) to a chimney (112) through valves in the torrefaction reactor (102) after a sufficient heating time.

3. The system (100) as claimed in claim 2, wherein the sufficient temperature for torrefying the in-feed raw material is of about 250 degrees Celsius to 300 degrees Celsius.

4. The system (100) as claimed in claim 1, wherein the torrefaction reactor (102) comprises spikes (202b) on an inner wall (202a) of the torrefaction reactor (102), wherein the spikes (202b) are configured to de-bale the in-feed raw material when the in-feed raw material is feed into the rotating drum (202) in a bales form.

5. The system (100) as claimed in claim 1, further comprising: a first blower (106) coupled between the settling tank (104) and the ignition chamber (108), the first blower (106) configured to create a suction force to draw out the volatiles (216) from the torrefaction reactor (102) and the settling tank (104) and transmit to the ignition chamber (108).

6. The system (100) as claimed in claim 1, further comprising: a second blower (114) coupled to the heat exchanger (110), the second blower (114) configured to provide the suction force to draw air from an outer atmosphere, and waste flue gas from the furnace (204), and transmit to the heat exchanger (110) for generating the hot air (238).

7. The system (100) as claimed in claim 1, further comprising: a third blower (114) coupled between the heat exchanger (110) and a chimney (112), the third blower (114) configured to provide the suction force to draw out the hot flue gas (224), and the hot air (238) from the torrefaction reactor (102) for discharging the hot flue gas (224), and the hot air (238) through the chimney (112) passing through the heat exchanger (110).

8. The system (100) as claimed in claim 1, wherein each of the first door (240a), and the second door (240b) comprises swinging arms attached to a column on a side of the first door (240a), and the second door (240b) for operating the first door (240a), and the second door (240b) between the open and closed position.

9. The system (100) as claimed in claim 8, wherein the rotating drum (202) is configured to operate at a positive pressure for generating the torrefied mass when the first door (240a), and the second door (240b) are operated in the closed position, the positive pressure created within the rotating drum (202) expel oxygen from the rotating drum (202) to an outer atmosphere.

10. The system (100) as claimed in claim 1, wherein the central rotating tube (218) comprises: a bearing less static stuffed box sealing piping arrangement configured to encircle the central rotating tube (218); an SS below arrangement configured to provide flexibility to the central rotating tube (218) to enable the central rotating tube (218) to adjust to the movement of the rotating drum (202), thereby neutralizing ovality created by the rotating drum (202); and a base spring plate system supporting the central rotating tube (218) and configured to adjust the ovality of the rotating drum (202).

11. The system (100) as claimed in claim 1, wherein the central rotating tube (218) is configured on both feeding side and discharging side, when the volatiles (216) generated is higher than an optimum value.

12. The system (100) as claimed in claim 1, wherein the fluid for indirectly cooling the torrefied mass comprises one of a liquid coolant (304) and a cool air (312) from a chilling plant or a dessert cooler.

13. The system (100) as claimed in claim 12, further comprising: a pump (302) fluidically coupled to the cooling tower (116), the pump (302) configured to circulate the liquid coolant (304) to the rotating drum (202) via one or more inlets (306) of the torrefaction reactor (102) for indirectly cooling the torrefied mass; and a collector tank (310) fluidically coupled to the cooling tower (116) via a recirculation pump (308), the collector tank (310) configured to receive the liquid coolant (304) from the torrefaction reactor (102) upon indirectly cooling the torrefied mass, wherein the liquid coolant (304) is recirculated to the cooling tower (116) by the recirculation pump (308).

14. The system (100) as claimed in claim 12, wherein the cooling tower (116) fluidically coupled to the heat exchanger (110) is configured to circulate the cool air (312) to the torrefaction reactor (102) via one or more pipes (314) of the torrefaction reactor (102) for indirectly cooling the torrefied mass.

15. The system (100) as claimed in claim 12, wherein the torrefied mass generated upon indirectly heating the in-feed raw material is allowed to cool naturally.

16. The system (100) as claimed in claim 1, wherein the in-feed raw material is subjected to the torrefaction reactor (102) in a loose form.

17. The system (100) as claimed in claim 16, further comprising: a segregating apparatus (400), comprising: an integrated bag opener and a stone breaker (402) configured to crush solid mineral materials present in the loose form in-feed raw material, an integrated ballistic and air density separator (404) for segregating the loose form in- feed raw material to heavy fraction (404a), medium fraction (404c) and light fraction (404b), wherein the medium fraction (404c) is fed to the torrefaction rector (102), a magnetic separator (406) configured to separate ferrous materials present in the heavy fraction (404a), and an eddy current separator (408) configured to segregate non-ferrous materials present in the heavy fraction (404a); and a shredder (410) configured to convert at least one combustible material from the heavy fraction (404a), and the light fraction (404b) into simpler fragments for feeding to the torrefaction reactor (102).

18. The system (100) as claimed in claim 1, further comprising: a gear mechanism (208a) and a pinion (208b) operatively coupled to the rotating drum (202) via a control switch (212) coupled to an actuator (210), the gear mechanism (208a) and the pinion (208b) are collectively operated by the control switch (212) and the actuator (210) to rotate the rotating drum (202) in the axis of rotation (Rl) during a torrefaction process.

19. The system (100) as claimed in claim 1, wherein the torrefaction reactor (102) is positioned over a fulcrum (232), thereby enabling the torrefaction reactor (102) to selectively adjust between a feeding side and a discharge side for receiving the in -feed raw material and discharging the torrefied mass out of the system (100) respectively.

20. A method (500) for torrefaction of in-feed raw material comprising at least one of a refuse derived fuel (RDF) and a lignocellulosic biomass, the method (500) comprising: receiving the in-feed raw material within a rotating drum (202) of a torrefaction reactor

(102); operating a plurality of burners (214) associated with a furnace (204) of the torrefaction reactor (102) for indirectly heating the in-feed raw material within the rotating drum (202) to generate volatiles (216); routing the volatiles (216) via central rotating tube (218) positioned at a central portion (228c) of the torrefaction reactor (102) to a settling tank (104), the volatiles (216) passing through the settling tank (104) enable tar (230) to settle at a bottom portion (220a) of the settling tank (104); routing the volatiles (216) from the settling tank (104) to an ignition chamber (108) for burning the volatiles (216) to generate hot flue gas (224); generating hot air (238) by an heat exchanger (110) by receiving air from an outer atmosphere and waste flue gas from the torrefaction reactor (102) under influence of a third blower (120); transmitting the hot flue gas (224), and the hot air (238) into a space between the rotating drum (202) and the furnace (204) for torrefying the in-feed raw material to obtain the torrefied mass; and circulating a fluid from a cooling tower (116) to the torrefaction reactor (102) for indirectly cooling the torrefied mass within the torrefaction reactor (102).

21. The method (500) as claimed in claim 20, further comprising: monitoring a temperature of the rotating drum (202), upon receiving the hot flue gas (224) and the hot air (238) for torrefying the in-feed raw material; deactivating the plurality of burners (214) associated with the furnace (204) when the temperature of the hot flue gas (224) and the hot air (238) are determined to be sufficient for torrefying the in-feed raw material to generate the torrefied mass; and diverting the hot air (238), and the hot flue gas (224) from the ignition chamber (108) and the heat exchanger (110) to a chimney (112) through valves in the torrefaction reactor (102) after a sufficient heating time.

22. The method (500) as claimed in claim 21, wherein the sufficient temperature for torrefying the in-feed raw material is of about 250 degrees Celsius to 300 degrees Celsius.

23. The method (500) as claimed in claim 20, further comprising: providing a suction force by a first blower (106) coupled between the settling tank (104) and the ignition chamber (108) to draw out the volatiles (216) from the torrefaction reactor (102) and the settling tank (104) and transmit to the ignition chamber (108).

24. The method (500) as claimed in claim 20, further comprising: providing a suction force by a second blower (114) coupled to the heat exchanger (110) to draw air from an outer atmosphere, and waste flue gas from the furnace (204) and transmit to the heat exchanger (110) for generating the hot air (238).

25. The method (500) as claimed in claim 20, further comprising: providing a suction force by a third blower (120) coupled between the heat exchanger (110) and a chimney (112) to draw out the hot flue gas (224), and the hot air (238) from the torrefaction reactor (102) for discharging the hot flue gas (224), and the hot air (238) through the chimney (112) passing through the heat exchanger (110).

26. The method (500) as claimed in claim 20, wherein the fluid for indirectly cooling the torrefied mass comprises one of a liquid coolant (304) and a cool air (312) from a chilling plant or a dessert cooler.

27. The method (500) as claimed in claim 26, further comprising: operating a pump (302) fluidically coupled to the cooling tower (116) to circulate the liquid coolant (304) to the rotating drum (202) via the one or more inlets (306) for indirectly cooling the torrefied mass; receiving by a collector tank (310), the liquid coolant (304) from the torrefaction reactor (102) upon indirectly cooling the torrefied mass; and circulating the liquid coolant (304) to the cooling tower (116) by a recirculation pump (308) coupled between the cooling tower (116) and the collector tank (310).

28. The method (500) as claimed in claim 26, wherein the cooling tower (116) is fluidically coupled to the heat exchanger (110) to circulate the cool air (312) to the torrefaction reactor (102) from one or more pipes (314) of the torrefaction reactor (102) for indirectly cooling the torrefied mass.

29. The method (500) as claimed in claim 20, wherein the in-feed raw material is subjected into the torrefaction reactor (102) in a loose form.

30. The method (500) as claimed in claim 29, further comprising: routing the loose form in-feed raw material through an integrated bag opener and a stone breaker (402) of a segregating apparatus (400) for crushing solid mineral materials present in the loose form in-feed raw material; transmitting the loose form in-feed raw material on an integrated ballistic and air density separator (404) for segregating the in-feed raw material to heavy fraction (404a), light fraction (404b) and medium fraction (404c), wherein the medium fraction (404c) is feed into the rotating drum (202); transmitting the heavy fraction (404a) to an magnetic separator (406) of the segregating apparatus (400) to segregate ferrous materials from the heavy fraction (404a); transmitting the heavy fraction (404a) to an eddy current separator (408) of the segregating apparatus (400) to segregate non-ferrous materials from the heavy fraction (404a); transmitting at least one combustible material present in the heavy fraction (404a), and the light fraction (404b) to a shredder (410) for converting the at least one combustible material and the light fraction (404b) into simpler fragments; and feeding the small fragments of the loose form in-feed raw material to the torrefaction reactor (102) for torrefaction.