Description:FIELD
The present disclosure relates to industrial processing technologies.
DEFINITIONS
As used in the present disclosure, the following terms are generally intended to have the meaning as set forth below, except to the extent that the context in which they are used, indicates otherwise.
Bagacillo: The term “Bagacillo” refers to fine fraction of bagasse obtained by screening, generally used as a filter aid in filtration.
Clarification: The term “clarification” refers to a process for the separation of suspended solids by sedimentation from liquid such as juice. The freshly pressed juice contains suspended solids and colloidal particles that are deliberately precipitated, and this precipitation is called clarification.
Clarifier: The term “clarifier” refers to equipment that is used to perform the clarification process.
Feed juice: The term “feed juice” refers to juice obtained from sugar cane or sugar beet, fruits or vegetables.
Flash tank: The term ‘flash tank’ refers to a tank that is placed upstream to the lamella clarifier equipment, that enables gases in the juice to be removed and ensures that the juice runs at a constant temperature to the lamella clarifier equipment.
Flashing process: The term “flashing process” or “flash evaporation” refers to a process in which a liquid undergoes a sudden reduction in pressure, causing a portion of the liquid to vaporize or "flash" into steam or vapour.
Flocculant: The term “flocculant” refers to a substance that promotes the coagulation of suspended and colloidal particles in a liquid.
Lamella Clarifier: The term “Lamella clarifier” refers to a compact, inclined plate-type clarifier, which is conventionally used for the clarification of water, wastewater and liquid having suspended and colloidal particles. The principle of lamella clarifier is based on settling under gravity, providing a number of inclined plates to form a higher settling area in compact equipment. The clarifier consists of a series of inclined overlapping plates, which are arranged to form a separate sedimentation chamber or the cells between each pair of adjacent plates.
Mud Boot: The term “mud boot” refers to the bottom part of a clarifier that receives the semi-solid mud or the precipitate from the clarifier under the action of gravity.
Scraper: The term “scraper” refers to a part that scraps the semi-solid mud or precipitate that sticks to the inner wall of the conical portion of the clarifier and mud boot of the clarifier.
Surface loading rate: The term “surface loading rate” refers to a parameter to measure the capacity of any clarifier, unit of which is meter/hour, and can be obtained by dividing the liquid flow rate (meter3/hour) by the cross-sectional area (meter2).
Entrapped gases: The term “entrapped gases” refers to occluded air and other gases, including both dissolved and undissolved gas bubbles, that are held within or dispersed throughout the feed juice.
Side wall: The term “side wall” refers to the boundary surface, functioning as a partition to guide the flow of the fluid.
Equipment: The term “equipment” refers to tools, devices, or systems used to perform specific functions, including an apparatus or machinery designed for particular operations.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
Juices are extracted liquid portions from the pulp of a fruit, whole fruit, sugar cane, sugar beet or vegetables, and other base product depending on the type of feed stock used.
Typically, sugar cane juice received from the mills or diffusers, commonly termed as raw juice, mixed juice or draft juice, is turbid in appearance and quality is inconsistent. This juice besides containing suspended impurities of sources such as fine bagacillo, also contains a number of impurities either in a dissolved state or in colloidal condition. The impurities are in a dispersed and suspended state and also include soil and fine particles of bagasse extracted during shredding. Due to this colloidal state, the raw juice has relatively higher turbidity and colour value, which is undesirable.
The undesirable impurities need to be removed from raw juice so that clear juice suitable for the sucrose crystallization process can be obtained. The crystallization process of the clear juice yields white sugar. The colloidal particulates in juices are separated from the liquids by a process of clarification. In the case of sugarcane juice, it must be clarified to eliminate suspended impurities, colloids and to remove a maximum amount of non-sugar material to produce good quality sugar.
There are two types of reagents that can be used for the juice clarification process. First reagent can be used in substantial amounts such as lime, phosphates, sulphur and the like are the main clarificants. Second reagents can be additives, flocculants and the like that are employed for assisting/promoting, coagulation and settling operations. Further, in the process of clarification, the treatment of juice by heat and clarifying agents results in the formation of a precipitate which when separated in the clarifier, yields transparent juice. The clarification of sugarcane juice occurs by coagulation, flocculation and precipitation of the colloids and pigmented substances, which are eliminated in this process.
The clarification process is commonly performed by using continuous clarifiers such as DorrTM, GraverTM and RapiDorrTM clarifiers, which are multi-tray, high-retention-time (HRT) clarifiers and has a residence time of about 2.5 to 3 hours. A multi-tray clarifier is a large cylindrical tank and is generally divided into 4 to 5-tiered compartments to increase the area of settling. The other types of clarifiers having retention of about 40 minutes used for the clarification of juice are short retention time clarifiers and low turbulence clarifiers. However, these clarifiers require a large footprint area, longer retention time, and high cost to build. Therefore, low retention time is desired, particularly for the sugarcane juice as sugar loss due to inversion is directly proportional to the retention time.
Therefore, there is a need for clarifier equipment and a process for the clarification of the feed juice that mitigates the aforementioned drawbacks or at least provides an alternative solution.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows.
An object of the present disclosure is to ameliorate one or more problems of the background or to at least provide a useful alternative.
Another object of the present disclosure is to provide equipment for the clarification of feed juice, with a relatively low retention time.
Still another object of the present disclosure is to provide a process for the clarification of feed juice, which also has a relatively low retention time.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY
The present disclosure relates to equipment for the clarification of feed juice. The equipment comprises a flash tank for receiving unclarified feed juice and removing entrapped gases from the unclarified feed juice by flashing to obtain a flashed unclarified feed juice first stream and a vessel for receiving the first stream of flashed unclarified feed juice and separating the received first stream into a second stream of clarified juice and a third stream containing semi-solid mud slurry. The vessel comprises i) an operative bottom section of the vessel having a conical unit for receiving the first stream of flashed unclarified feed rich in solid particles through an operative top section of the vessel and is configured to allow solid particles in the first stream to settle as semi-solid mud slurry at the base of the bottom section and is further configured to allow the first stream with reduced solid particles to rise up at the top of the conical unit; ii)the operative top section of the vessel having at least one lamella unit configured to receive the first stream with reduced solid particles from the top of the conical unit and clarify the first stream to obtain the second stream of clarified juice from a clear juice outlet; and iii) a mud boot arranged below the conical unit to receive and discharge the semi-solid mud slurry as a third stream. The equipment is characterized by further comprising a scraper having scraping elements at extremities. The scraper having a shaft drive is mounted on a support attached to an operative top side of the vessel and configured to extend to the mud boot. The scraper is configured to be rotatably driven about an operative vertical axis of the vessel to remove deposits of semi-solid mud slurry from the inner surfaces of the conical unit and the mud boot by a scraping action.
In accordance with the present disclosure, the mud boot is configured to have an operative top portion having cylindrical geometry of a diameter to height ratio in the range of 1:1 to 1.5:1. The mud boot is further configured to have an operative bottom portion in the shape of a frustum of a cone making an angle with a vertical axis in the range of 40 degrees to 50 degrees.
In accordance with the present disclosure, the mud boot is configured with a mud boot outlet nozzle at an operative bottom side of the mud boot. The mud boot outlet nozzle is configured to withdraw the third stream of semi-solid mud slurry through the operative bottom side of the mud boot.
In accordance with the present disclosure, the lamella unit is configured to have a plurality of inclined plates arranged in two adjacent sets and at least one channel formed by side walls of two adjacent sets. The plurality of inclined plates are configured at an inclination to a vertical axis of the vessel, the inclination being in the range of 25 degrees to 35 degrees.
In accordance with the present disclosure, the plurality of inclined plates are arranged in parallel and interspaced with a distance in the range of 25 mm to 75 mm. The inclined plates have a thickness in the range of 2 mm to 10 mm.
In accordance with the present disclosure, the lamella unit is fluidly connected with the mud boot and the clear juice outlet. The lamella unit is further configured to receive the flashed unclarified feed juice through at least one channel and separate the flashed unclarified feed juice in a clarified form as the second stream is transported to the clear juice outlet while the remaining portion including semi-solid mud slurry is transported to the mud boot.
In accordance with the present disclosure, the scraper includes at least one scraper arm in the conical unit and at least one mud boot scraper arm. At least one scraper arm and at least one mud boot scraper arm are attached to the shaft drive. At least one scraper arm is configured to remove the semi-solid mud slurry from the inner surface of the conical unit. The mud boot scraper arm is configured to remove the semi-solid mud slurry from the inner surface of the mud boot.
In accordance with the present disclosure, the shaft drive is supported on the operative bottom portion of the mud boot through a shaft support.
In accordance with the present disclosure, the conical unit is configured at the operative bottom section of the vessel and has a shape of a frustum of a cone having an angle with a vertical axis in the range of 25 degrees to 35 degrees.
In accordance with the present disclosure, the lamella unit and the conical unit have different operative height dimensions. The ratio of the height of the lamella unit to the height of the conical unit is in the range of 1:2 to 1:2.5.
In accordance with the present disclosure, the vessel receives the first stream of flashed unclarified feed juice through a feed inlet pipe. The feed inlet pipe has a first end and a second end, wherein the first end is fluidly connected to an operative bottom portion of the flash tank and the second end is fluidly connected to the operative top section of the vessel. The feed inlet pipe is configured to receive the flashed unclarified feed juice from the flash tank.
In accordance with the present disclosure, the feed inlet pipe includes a flocculant adding point from an automatic flocculant dosing system. The flocculant adding point is configured to feed a flocculant to the flashed unclarified feed juice in the feed inlet pipe.
In accordance with the present disclosure, the feed inlet pipe is in fluid communication with a distributor. The distributor is configured to distribute the flashed unclarified feed juice from the feed inlet pipe to at least one channel formed by two adjacent sets of the plurality of inclined plates of the lamella unit.
In accordance with the present disclosure, the conical unit at the operative bottom section of the vessel is configured to have at least six mud sampling ports to monitor the mud level at different points within the vessel.
In accordance with the present disclosure, the vessel is attached with a plurality of sensors. The plurality of sensors are selected from the group consisting of a pH sensor, a temperature sensor, a turbidity sensor and a colour sensor.
The present disclosure further relates to a process for the clarification of a feed juice, the process comprises receiving an unclarified feed juice having a predetermined temperature in a flash tank to obtain a flashed unclarified feed juice first stream. Adding a predetermined amount of flocculant to the flashed unclarified feed juice received from the flash tank to obtain a feed mixture having the flashed unclarified feed juice. Distributing the feed mixture to an operative bottom section of the vessel at a first predetermined flow rate through at least one channel of the lamella unit by maintaining a predetermined surface loading rate to obtain semi-solid mud slurry at an operative bottom section at a predetermined rate of mud settling and a juice with reduced semi-solid mud at the top surface of a conical unit. Allowing separation of the juice with reduced semi-solid mud slurry at the top surface of the conical unit through the transportation from two sets of a plurality of inclined plates of the lamella unit to obtain clarified juice at the outlet in a predetermined time period and settling further the semi-solid mud slurry at the operative bottom section. Scraping the semi-solid mud slurry from the operative bottom section of the vessel having a conical unit and a mud boot of the vessel by using a scraper rotating at a predetermined speed. Discharging the semi-solid mud slurry scraped from the operative bottom section at a second predetermined flow rate through a mud boot outlet nozzle as a third stream.. And collecting the clarified juice as a second stream from a clear juice outlet of the vessel.
In accordance with the present disclosure, the predetermined temperature of unclarified feed juice is in the range of 102 C to 106 C.
In accordance with the present disclosure, the first predetermined flow rate of the feed mixture to the vessel is in the range of 150 tons per hour to 250 tons per hour.
In accordance with the present disclosure, the predetermined amount of the flocculant is in the range of 2 ppm on cane to 6 ppm on cane.
In accordance with the present disclosure, the predetermined surface loading rate is in the range of 20 meters per hour to 30 meters per hour.
In accordance with the present disclosure, the predetermined time period of obtaining clarified juice is in the range of 5 minutes to 10 minutes.
In accordance with the present disclosure, the rotating speed of the scraper is in the range of 2 to 5 rotations per hour.
In accordance with the present disclosure, the second predetermined flow rate of discharging the semi-solid mud is in the range of 9 metric tons per hour to 15 metric tons per hour.
In accordance with the present disclosure, the mud settling rate inside the vessel is in the range of 250 mm per minute to 350 mm per minute.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
The present disclosure will now be described with the help of the accompanying drawing, in which:
Fig. 1 illustrates a schematic drawing of equipment (1000) in accordance with the present disclosure;
Fig. 2 illustrates an arrangement of the inclined plates (lamella plates) in a lamella unit (400) of the equipment in accordance with the present disclosure;
Fig. 3 illustrates a line diagram of a mud boot (600) of the equipment in accordance with the present disclosure;
Fig. 4 illustrates a line diagram of a scraping arrangement in the vessel of the equipment in accordance with the present disclosure;
Fig. 5a, 5b, 5c, 5d, 5e and 5f illustrates various views of the equipment in accordance with the present disclosure, wherein Fig. 5a illustrates a front view, Fig. 5b illustrates a side view, Fig. 5c illustrates a back view, Fig. 5d illustrates a front isometric view, Fig. 5e illustrates a top view, and Fig. 5f illustrates a back isometric view in accordance with the present disclosure;
Fig. 6 illustrates a line diagram of feed juice, clarified juice (clear juice) and mud in the lamella clarifier vessel in accordance with the present disclosure;
Fig. 7 illustrates a conventional lamella clarifier (50) as demonstrated in comparative example 4 of the present disclosure;
Fig. 8a, 8b and 8c illustrate images of the collected juice samples, wherein Fig. 8a illustrates the juice sample collected from an inlet of the equipment, Fig. 8b illustrates the juice sample collected after the addition of a flocculant, and Fig. 8c illustrates the juice sample collected from an outlet of the equipment of the present disclosure;
Fig. 9a illustrates the graphs comparing the transmittance at 560 nm of clear (clarified) juice obtained by using the Louisiana Low Turbulence (LLT) clarifier and the equipment of the present disclosure; and
Fig. 9b illustrates the graphs comparing the turbidity at 900 nm of clear (clarified) juice obtained by using the Louisiana Low Turbulence (LLT) clarifier and the equipment of the present disclosure.
LIST OF REFERENCE NUMERALS
Reference numerals Description
1000 Equipment in accordance with the present disclosure
100 Flash tank
102 Inlet to Flash tank
104 Overflow
106 Steam outlet
200 Vessel
202 Support for shaft drive
204 Clear juice outlet
400 Lamella Unit
401 Channel
402 Plurality of inclined plates
402’ and 402” Two adjacent sets of plurality of inclined plates
404 Holding plate
406 Guide plate
500 Conical Unit
502 Mud Sampling ports
600 Mud boot
602 An operative top portion of the mud boot having a cylindrical geometry
604 An operative bottom portion of a mud boot having a shape of frustum of a cone
606 Mud boot outlet nozzle
700 Scraper
702 Shaft drive (2HP Motor with 2 staged reduction gearbox)
704 Scraper arm in conical unit
706 Mud boot scraper arm
708 Shaft support
800 Feed inlet
802 Distributor
804 Flocculant addition point from automatic flocculant dosing system
900 Plurality of sensor (not shown in Figure)
050 Lamella clarifier in accordance with comparative example 4
002 Juice inlet
004 Flash tank
006 Overflow
008 Flocculant inlet
010 Feed inlet to a vessel or flashed juice outlet from the flash tank
012 Flash tank level control valve
014 Feed juice inlet to juice distributor
016 Clear juice outlet
018 Juice distributor
020 Mud cone
022 Mud sample port
024 Sludge outlet
026 Manhole
028 Manifold
030 Water flush line
032 Line to visualize the consistency of the mud (not shown in the figure)
034 Support
036 Lamella unit
038 Vessel
DETAILED DESCRIPTION
The present disclosure relates to equipment and a process for the clarification of feed juice.
Embodiments, of the present disclosure, will now be described with reference to the accompanying drawing.
Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, known processes or well-known equipment or structures, and well known techniques are not described in detail.
The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms "a,” "an," and "the" may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms "comprises," "comprising," “including,” and “having,” are open ended transitional phrases and therefore specify the presence of stated features, integers, steps, operations, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The particular order of steps disclosed in the method and process of the present disclosure are not to be construed as necessarily requiring their performance as described or illustrated. It is also to be understood that additional or alternative steps may be employed.
The terms first, second, third, etc., should not be construed to limit the scope of the present disclosure as the aforementioned terms may be only used to distinguish one element, component, region, layer or section from another component, region, layer or section. Terms such as first, second, third etc., when used herein do not imply a specific sequence or order unless clearly suggested by the present disclosure.
As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed elements.
Juices are the extracted liquid portions from the pulp of the fruit, whole fruit, sugarcane, sugar beet or vegetables, depending on the type of the source used.
Typically, sugar cane juice received from the mills or diffusers, commonly termed as raw juice, mixed juice or draft juice, is turbid in appearance and quality is inconsistent. This juice besides containing suspended impurities of sources such as fine bagacillo, also contains a number of impurities either in dissolved state or in colloidal condition. The impurities are in a dispersed and suspended state and also include soil and fine particles of bagasse extracted during milling/diffusion. Due to this colloidal state, the raw juice has relatively higher turbidity and colour value, which is undesirable.
The undesirable impurities need to be removed from raw juice so that clear juice suitable for the sucrose crystallization process can be produced. The crystallization process of the clear juice yields white sugar. The colloidal particulates in juices are separated from the liquids by a process of clarification. In the case of sugarcane juice, it must be clarified to eliminate suspended impurities, colloids and to remove a maximum amount of non-sugar material to produce good quality sugar.
There are two types of reagents that can be used for the juice clarification process. First reagent can be used in substantial amounts such as lime, phosphates, sulphur and the like are the main clarificants. Second reagents can be additives, flocculant and the like that are employed for assisting/promoting, coagulation and settling operations. Further, in the process of clarification, the treatment of juice by heat and clarifying agents results in the formation of a precipitate which when separated in the clarifier, yields transparent juice. The clarification of sugarcane juice occurs by coagulation, flocculation and precipitation of the colloids and pigmented substances, which are eliminated later by decanting and filtration.
The clarification process is commonly performed by using continuous clarifiers such as DorrTM, GraverTM and RapiDorrTMclarifiers, which are multi-tray, high-retention-time (HRT) clarifiers and has residence time of about 2.5 to 3 hours. A multi-tray clarifier is a large cylindrical tank and is generally divided into 4 to 5 tiered compartments to increase the area of settling. The other types of clarifiers having retention of about 40 minutes used for the clarification of juice are short retention time clarifiers and low turbulence clarifiers. However, these clarifiers require a large footprint area, longer retention time, and high cost to build. Therefore, low retention time is desired, particularly for the sugarcane juice as sugar loss due to inversion is directly proportional to the retention time.
In an aspect, the present disclosure provides equipment (1000) for the clarification of feed juice.
Referring to Fig. 1 to Fig. 6, particularly in Fig. 1, the equipment (1000) comprises a flash tank (100) and a vessel (200). The flash tank (100) and the vessel (200) are configured to be supported on a structure fixed on a ground surface. The flash tank (100) is configured to receive unclarified feed juice having a predetermined temperature and remove entrapped gases from the unclarified feed juice by flashing to obtain the first stream of flashed unclarified feed juice. The vessel (200) is configured to receive the first stream of flashed unclarified feed juice and separate the received first stream into a second stream of clarified juice and a third stream containing semi-solid mud slurry. The vessel comprises an operative bottom section, an operative top section and a mud boot (600). The operative bottom section of the vessel (200) has a conical unit (500) for receiving the first stream of flashed unclarified feed which is rich in solid particles through an operative top section of the vessel and configured to allow solid particles in the first stream to settle as semi-solid mud slurry at the base of the bottom section. The operative bottom section of the vessel (200) is further configured to allow the first stream with reduced solid particles to rise up at the top of the conical unit (500). The operative top section of the vessel (200) has at least one lamella unit (400) configured to receive the first stream with reduced solid particles from the top of the conical unit (500) and clarify the first stream to obtain the second stream of clarified juice from a clear juice outlet (204). The mud boot (600) is arranged operatively below the conical unit (500) to receive and discharge the third stream of semi-solid mud slurry.
In accordance with the present disclosure, the predetermined temperature is in the range of 102 C to 106 C. In an exemplary embodiment, the predetermined temperature is 105 C.
The flash tank (100) includes an inlet (102) for feed juice which is unclarified feed juice preferably perpendicular to the flash tank (100). The flash tank (100) further includes a steam outlet (106) to remove the steam and an overflow (104). The flash tank (100) is configured to supply the flashed unclarified feed juice to the vessel (200), the flow of the flashed unclarified feed juice is controlled by using a control valve.
The mud boot (600) is configured to be attached to an operative bottom side of the vessel (200) and further configured to receive a semi-solid mud separated from the flashed unclarified feed juice in the vessel (200) under the action of gravity.
The vessel (200) comprises a scraper (700). The scraper (700) has scraping elements at the extremities.The scraper (700) has a shaft drive (702) and is mounted on a support (202) attached to an operative top side of the vessel (200) and is configured to extend to the mud boot (600). The scraper (700) is configured to be rotatably driven about an operative vertical axis of the vessel (200). The scraper (700) is further configured to remove deposits of semi-solid mud from the inner surfaces of the operative bottom section of the vessel (200) including the conical unit (500) and the mud boot (600) by a scraping action.
The clear juice outlet (204) is configured on the operative top side of the vessel (200) to transport the separated clarified juice from the flashed unclarified feed juice to another vessel.
The lamella unit (400) is configured on the operative top section of the vessel (200). The lamella unit (400) includes the plurality of inclined plates (402) attached to its inner surface, and the lamella unit (400) configured is fluidly connected with the mud boot (600) and the clear juice outlet (204). The lamella unit (400) further includes at least one channel (401) formed by side walls of two adjacent sets (402’, 402”) of the plurality of inclined plates (402) to receive the flashed unclarified feed juice and transfer it to the operative bottom section of the vessel including a conical unit (500) and a mud boot (600). The lamella unit (400) is further configured to receive and separate the flashed unclarified feed juice, to the clarified form of the feed juice being transported to the clear juice outlet (204) while the remaining portion including semi-solid mud being transported to the operative bottom section of the vessel preferably to the mud boot (600).
In accordance with an embodiment of the present disclosure, the at least one channel (401) is formed by the two adjacent sets (402’, 402”) of a plurality of inclined plates (402). The channel (401) creates space within the cubical portions of the operative top section of the vessel and outside the two adjacent sets (402’, 402”), through which the feed juice flows to the operative bottom section of the vessel.
The equipment (1000) includes the flash tank (100) and the vessel (200) configured to be supported on a structure fixed on a ground surface. The support for the structure has at least four vertical columns and cross beams. The cross beams strengthen the structure.
The equipment (1000) further includes a plurality of inclined plates (402) attached to the inner surfaces of the lamella unit (400) at the operative top section of the vessel (200). The inclined plates (402) are configured to extend in an operative vertical direction (V) of the vessel. The inclined plates (402) are configured to receive the flashed unclarified feed juice from the top of conical unit (500) and separate the juice in the clarified form to transport it to the outlet (204) as a second stream of clarified juice. The inclined plates (402) facilitate the settling of solid particles from the flashed unclarified feed juice, thereby allowing the solid particles to slide down to the operative bottom section of the vessel (200) and form semi-solid mud (precipitate).
In accordance with an embodiment of the present disclosure, the inclined plates (402) are arranged in the vessel with the help of holding plates (404) and guide plate (406) as shown in Fig. 2.
In accordance with an embodiment of the present disclosure, the lamella unit (400) at the operative top section of the vessel (200) has a cubical-type geometry and is further attached to the plurality of inclined plates arranged in two adjacent sets (402’, 402”). The plurality of inclined plates (402) is configured at an inclination to a vertical axis of the vessel (200). The inclination of the inclined plates with respect to the vertical axis is the range of 25 degrees to 35 degrees. In an exemplary embodiment, the inclination of the inclined plates with respect to the vertical axis is 30 degrees.
In accordance with an embodiment of the present disclosure, the equipment (1000) includes the inclined plates (402) in the range of 100 plates to 120 plates. In an exemplary embodiment, the lamella unit (400) has a total of 104 inclined plates arranged in two sets of 52 each.
In accordance with the present disclosure, the plurality of inclined plates (402) are arranged in parallel and interspaced from each other at a distance in the range of 25 mm to 75 mm. In an exemplary embodiment, the inclined plates are spaced apart from each other at a distance of 50 mm.
In accordance with the present disclosure, the inclined plates (402) have a thickness in the range of 2 mm to 10 mm. In the exemplary embodiment, the inclined plates (402) have a thickness of 6 mm.
In an exemplary embodiment, each of the inclined plate has a dimension of 1524 mm width, 1524 mm height and 6 mm thick. The inclined plates are positioned vertically such that the plates receive the unclarified feed juice to be separated.
The inclined plates are cold rolled, heat treated, pickle and skin passed (2B surface finish). The surface smoothness of the inclined plates may vary depending on the type of inclined plates used.
In accordance with the present disclosure, the conical unit (500) configured at the operative bottom section of the vessel (200) has the shape of a frustum of a cone having an angle with a vertical axis in the range of 25 degrees to 35 degrees. In an exemplary embodiment, the conical unit (500) at the operative bottom section of the vessel (200) has the shape of a frustum of a cone having an angle with a vertical axis of 30 degrees.
The lamella unit (400), and the conical unit (500) have different operative height dimensions, the ratio of the height of the lamella unit (400) to the height of the conical unit (500) being in the range of 1:2 to 1:2.5. In an exemplary embodiment, the ratio of the height of the lamella unit (400) to the height of the conical unit (500) is in the range of 1:2.2.
The equipment (1000) comprises a mud boot (600), a scraper (700) and a clarified juice outlet (204).
Fig. 3 illustrates a line diagram of a mud boot of the equipment in accordance with the present disclosure. The mud boot (600) is configured to have an operative top portion having a cylindrical geometry (602) of a diameter-to-height ratio in the range of 1:1 to 1.5:1. In an exemplary embodiment, the mud boot (600) has a cylindrical geometry having a diameter to height ratio of 1.18:1.
In accordance with the present disclosure, the mud boot (600) is further configured to have an operative bottom portion having the shape of a frustum of a cone (604) having an angle with a vertical axis in the range of 40 degrees to 50 degrees. In an exemplary embodiment, the operative bottom portion of the mud boot has the shape of the frustum of a cone (604) having an angle with a vertical axis of 45 degrees.
In accordance with the present disclosure, the mud boot (600) is configured with a mud boot outlet nozzle (606) at an operative bottom side of the mud boot (600). The mud boot outlet nozzle (606) is configured to withdraw the third stream of semi-solid mud slurry from the operative bottom side of the mud boot (600).
In accordance with the present disclosure, the mud from the mud boot outlet nozzle still contains juice which can be recovered. A vacuum filtration unit is used to separate solid particles from the mud by using a vacuum to draw the liquid through a filter medium while leaving solid particles behind.
Fig. 4 illustrates a line diagram of a scraping arrangement in the vessel of the equipment (1000) in accordance with the present disclosure. In an embodiment, the scraper (700) is attached to at least one scraper arm (704) and at least one mud boot scraper arm (706). The at least one scraper arm (704) and the at least one mud boot scraper arm (706) are being attached to the shaft drive (702). The at least one scraper arm (704) is configured to remove the semi-solid mud slurry on the inner surface of the conical unit (500). The mud boot scraper arm (706) is configured to remove the semi-solid mud from the inner surface of the mud boot (600). The shaft drive (702) is supported on the operative bottom portion of the mud boot (600) through shaft support (708).
In an embodiment, the vessel (200) receives the first stream of flashed unclarified feed juice through a feed inlet pipe (800). The feed inlet pipe (800) has a first end and a second end. The first end is fluidly connected to an operative bottom portion of the flash tank (100). The second end is fluidly connected to the operative top section of the vessel (200). The feed inlet pipe (800) is configured to receive the flashed unclarified feed juice from the flash tank (100) and supply it to the channel (401) of the plurality of inclined plates (402) in the lamella unit (400).
In an embodiment, the feed inlet pipe (800) includes a flocculant adding point (804) from an automatic flocculant dosing system. The flocculant adding point (804) is configured to add a flocculant to the flashed unclarified feed juice in the feed inlet pipe (800). In an exemplary embodiment, the additive is a food-grade flocculant.
Flocculant, in powder or emulsion form, is very high molecular weight polymer. To ensure the efficiency of the clarification process, the preparation of the dilute polymer solution is critical.
The automatic flocculant preparation and the dosing system contain baffles that allow the circulation of the polymer preparation through a series of compartments. This ensures the optimum reaction time in each compartment and, a continuous concentration level, thereby avoiding any preferential route between the preparation compartment and the final dosing solution compartment.
This system is automated by the control panel connected to the ultrasonic level detector located above the dosing solution compartment. As soon as the solution in the dosing compartment reaches “low level”, the detector activates the opening of the water feed electro valve and the start-up of the flocculant feeder. The water meter controls the flow continuously. As soon as the “high level” is reached, the process cycle stops, although the mixers continue to operate. The advantages are: the automatic dosing unit avoids the need for manual operations which prevents dosing errors, operation stops, and homogeneity in flocculant concentration and prevents dosing errors. High-efficiency mixers in the automatic dosing unit facilitate a low flow mixing for a homogeneous flocculant polymerization without mechanical deterioration. The intelligent automatic dosing unit that is regulated by an ultrasonic level switch is a liable and robust unit.
In an embodiment, the feed inlet pipe (800) is in fluid communication with a distributor (802), and the distributor (802) is configured to distribute the flashed unclarified feed juice from the feed inlet pipe (800) to the channel (401) of two sets (402’, 402”) of plurality of inclined plates (402) through the operative top section of the vessel (200).
In an embodiment, pathways are provided for two streams of flashed unclarified feed juice through a distributor to enter the lamella unit to transfer it to the operative bottom section of the vessel including the conical unit (500) and the mud boot (600). Juice gets clarified during travelling from the top surface of the conical unit (500) to an operative top side of the lamella unit through the gap between inclined plates. The mud gets settled to the bottom by gravity, further, the inclined plates also allow the remaining solid particles to slide down to the operative bottom section of the vessel (200).
In an embodiment, the conical unit (500) at the operative bottom section of the vessel (200) is configured to have at least six mud sampling ports (502) to monitor the mud level at different points within the vessel (200).
In an embodiment, the vessel (200) is attached to a plurality of sensors (900). The plurality of sensors (900) are selected from the group consisting of a pH sensor, a temperature sensor, a turbidity sensor, and a colour sensor.
In an exemplary embodiment, the temperature sensor is attached to the portion of the equipment from where the clarified juice and mud are leaving the equipment.
In an embodiment, the conical unit (500) is provided with view glasses (6 counts) to monitor the mud formation inside the vessel (200).
In an embodiment of the present disclosure, when there is uneven discharge of mud in the bottom section of the vessel (200) of the lamella clarifier, which leads to the building up of mud, there is a rotating scraper mounted in the conical portion of the vessel. The rotating scraper is mounted on the conical portion to prevent the chance of building up mud in the conical portion of the clarifier.
Referring to Fig. 1 of the present disclosure, the equipment of the present disclosure has a flash tank (100) positioned adjacent to a vessel (200) to supply a flashed unclarified feed juice to the equipment (1000) and a control valve to regulate the flow of the flashed unclarified feed juice to the lamella unit.
Fig. 5 illustrates a front view, a side view, a back view, a front isometric view, a top view, and a back isometric view of the equipment of the present disclosure.
Fig. 6 illustrates a flow of feed juice from the flash tank (100) to the lamella unit (400), a flow of clarified juice (clear juice) from the lamella unit (400) to the clear juice outlet (204), and a flow of direction of mud. The juice is treated with lime and sulphur dioxide and heated to 105 C before it enters to flash tank, in accordance with the present disclosure.
Referring to Fig. 7, a comparative lamella clarifier apparatus (050) is shown, having a flash tank (004) and lamella clarifier vessel (038). The flash tank includes a juice inlet (002) for feed juice preferably perpendicular to the flash tank (004). The feed juice is treated with lime and sulphur dioxide and heated to 105 C before it enters to flash tank. A feed inlet pipe (010) to the lamella clarifier vessel to facilitate the flow of the feed juice to the lamella unit from the flash tank. There is a provision of an overflow (006) to allow overflowing of feed juice in case the juice overflows. There is a provision for a flocculant inlet (008) and a control valve (012) after the juice outlet from the flash tank. The flashed juice enters the vessel (038) from the feed juice inlet (014) and is distributed by using a juice distributor (018). The lamella clarifier apparatus is supported on a structure (034). The lamella clarifier apparatus has vessel (038) having with a mud cone (020) at the bottom, and a lamella unit (036) with a juice outlet (016) at the top portion. The mud cone (020) is equipped with a plurality of sample ports (022) (for example, 6 count) to collect the mud sample to check mud consistency in the mud cone at different heights, and a sludge outlet (024) at the bottom. The mud cone (020) has a water flush line (030) and a manhole (026) as a provision to clean the mud cone (020).
The equipment (1000) of the present disclosure is efficient in comparison with conventional clarifier apparatuses.
In another aspect, the present disclosure provides a process for the clarification of a feed juice.
The process comprises the following steps:
An unclarified feed juice having a predetermined temperature is received in a flash tank (100) for flashing to obtain a flashed unclarified juice. The flash tank (100) is configured to perform flashing process.
The feed juice is treated with lime and sulphur dioxide and heated to a temperature in the range of 102 C to 106 C before it enters to flash tank. The hot, pressurized juice is then exposed to atmospheric pressure in the flash tank which is a closed vessel with adequate venting where it “flashes”, releasing all air bubbles adhering to the juice. This vessel also assures a more uniform temperature to the lamella unit (400).
In an embodiment, the predetermined temperature is in the range of 102 C to 106 C. In an exemplary embodiment, the predetermined temperature is 105 C.
A predetermined amount of flocculant is added to the flashed unclarified feed juice received from the flash tank (100) to obtain a feed mixture having the flashed unclarified feed juice.
In an embodiment, the predetermined amount of flocculant is in the range of 2 ppm to 6 ppm on cane. In an exemplary embodiment, the amount of flocculant is 4.5 ppm on cane.
The feed mixture is distributed to an operative bottom section of vessel (200) at a first predetermined flow rate through the channel (401) formed by two adjacent sets (402’, 402”) of a plurality of inclined plates (402) of the lamella unit (400) by maintaining a predetermined surface loading rate to obtain semi-solid mud slurry at the operative bottom section of the vessel at a predetermined rate of mud settling and a juice with reduced semi-solid mud slurry at the top surface of a conical unit (500).
The juice with reduced semi-solid mud slurry at the top surface of the conical unit (500) is allowed to separate through its transportation from two sets (402’, 402”) of a plurality of inclined plates of the lamella unit (400) to obtain clarified juice at the outlet (204) in a predetermined time period. The second stream of clarified juice is collected from a clear juice outlet (204) of the vessel (200).
In an embodiment, the predetermined time period is in the range of 5 minutes to 10 minutes. In an exemplary embodiment, the predetermined time period is 7 minutes.
In an embodiment, the first predetermined flow rate of the feed mixture to the vessel is in the range of 150 tons per hour to 250 tons per hour. In an exemplary embodiment, the flow rate of the feed mixture to the vessel is 210 tons per hour.
In an embodiment, the predetermined surface loading rate is in the range of 20 meters per hour to 30 meters per hour. In an exemplary embodiment, the surface loading rate of the equipment is 24 meters per hour.
In an embodiment, a mud settling rate inside the vessel is in the range of 250 mm per minute to 350 mm per minute. In an exemplary embodiment, the mud settling rate inside the vessel is 290 mm per minute.
In an embodiment, the flow rate of the flocculant solution to the vessel is in the range of 1 ton per hour to 3 tons per hour. In an exemplary embodiment, the flow rate of the flocculant to the vessel is 1.75 tons per hour.
The semi-solid mud slurry separated from the feed mixture is scraped from the operative bottom section of vessel (200) having the conical unit (500) and the mud boot (600) of the vessel (200) by using a scraper (700) rotating at a predetermined speed.
In an embodiment, the rotating speed of the scraper is in the range of 2 to 5 rotations per hour. In an exemplary embodiment, the rotating speed of the scraper is 3.7 rotations per hour.
The semi-solid mud slurry scraped from the operative bottom section of the vessel (200) is continuously discharged at a second predetermined flow rate through a mud-boot outlet nozzle (606) as a third stream.
In an embodiment, the second predetermined flow rate of discharging the semi-solid mud through the mud boot outlet nozzle (606) is in the range of 9 metric tons per hour to 15 metric tons per hour. In an exemplary embodiment, the flow rate of discharging the semi-solid mud through the mud boot outlet nozzle is 12.6 metric tons per hour.
In an embodiment, the discharge of mud from the mud boot outlet nozzle is controlled by facilitating a flow meter.
In an embodiment, the equipment (1000) is attached to an automatic dosing unit for feeding a high molecular weight food grade flocculant.
If the sugar plant is stopped for any reason for more than 8 hours, it is required to liquidate the clarifier to avoid the spoiling of the juice. The time required for liquidation process is proportional to the holding volume of the clarifier. Liquidation process is much easier and quicker with the equipment of the present disclosure as the holding volume of the equipment is much lesser than other type of clarifiers.
The foregoing description of the embodiments has been provided for purposes of illustration and not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment, but, are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.
The present disclosure is further illustrated herein below with the help of the following experiments. The experiments used herein are intended merely to facilitate an understanding of the 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 experiments should not be construed as limiting the scope of embodiments herein. These experiments can be scaled up to industrial/commercial scale and the results obtained can be extrapolated to industrial/commercial scale.
EXPERIMENTAL DETAILS
Example 1: Clarification of a feed juice by using the equipment of the present disclosure
In this example, an operative top portion of mud boot of the equipment was of cylindrical shape with the dimensions of 825 mm diameter and 700 mm height. The mud boot was provided with an extension of the scraper arms from the conical unit (bottom section of the vessel) to the mud boot. Two more mud sample points were provided in the conical unit above the sample points of the conventional Lamella clarifier. The flocculant (additive) dosing was automated with respect to inlet feed juice flow using a ratio control. The lamella unit had 104 inclined plates which were arranged in two sets parallel to each other, and the bottom section of the vessel had the shape of a frustum of a cone. The height ratio of the lamella unit and the conical unit was 1.84 meters: 4 meters.
Preparation of the feed juice:
The sugarcane was prepared and then juice was extracted by means of milling or diffusion. In milling, the juice was extracted by pressing the cane whereas in the diffuser juice was extracted on systematic counter-current washing of the cane by means of hot water. In practice, this was achieved by forming a bed of cane on a conveyor. Hot water was evenly sprayed at the discharge end of the conveyor and percolated through the bed of bagasse and the perforated slots of the conveyor. The hot water dissolves the sugar in the bagasse and the thin juice thus formed was collected in a hopper. This juice was moved forward one stage by pumping and the process was repeated until the juice reached the maximum concentration at the feed end of the diffuser.
The juice leaving the diffuser was treated with lime and SO2 gas and heated in three stages to a temperature of 105°C before the juice enters the flash tank in the form of unclarified feed juice.
The unclarified feed juice at 105 C was added to the flash tank of the equipment of the present disclosure at a flow rate of 210 tons per hour (or 200 m3/h) to obtain flashed unclarified juice. Afterwards, a flocculant was mixed at a rate of 4.5 to 5 ppm on cane to the obtained flashed unclarified juice. The flashed unclarified juice added with flocculant was allowed to be distributed over the channel (banks) formed by two sets of inclined plates (52 on each side) by maintaining a surface loading rate of 24 meters per hour to obtain a clarified juice in 7 minutes. Here, a high molecular weight poly acryl amide-based flocculant was used at a rate of 4.5 to 5 ppm on cane. The flocculant which is in powder form was diluted in warm water to form 0.05% flocculant solution.
To summarize, the flashed unclarified juice or feed juice entered the lamella unit through the distributor to distribute the flashed unclarified juice to the channel formed by of two adjacent sets of inclined plates. A flocculant was added before the feed entered the lamella unit using a flocculant adding point.
Further, a semi-solid mud separated from the flashed unclarified juice was scraped from the bottom portion of the vessel and the mud boot by using the scraper rotating at a speed of 3.7 revolutions per hour.
The semi-solid mud slurry was scraped from the vessel and the mud boot was continuously discharged from the mud boot outlet nozzle at 10 metric tons per hour, and the discharged semi-solid mud slurry was routed to the vacuum filter. The clarified juice was collected from an outlet at the top of the vessel and was routed to a clear juice tank.
Using the lamella clarifier of the present disclosure, the process of clarification was carried out for continuously at least for two seasons with occasional intermittent cleaning.
With the installation of scraper arms (704 and 706) in the mud cone and boot, mud thickness was improved from the top sampling points to the bottom sampling points. Outlet mud was always thicker than mud from the bottom sampling points, which was as desired. The vacuum filter worked well with the mud from the equipment. Mud settling rate in the equipment of the present disclosure was of 285±15 mm/min. The quality of the clarified juice was good with turbidity values of around 2 at 900 nm, and the percentage transmittance was always above 50 at 560 nm, which was desired.
Continuous operation of the equipment of the present disclosure over two cane seasons
The equipment of the present disclosure was allowed to run continuously for two cane seasons of about three to four months. Table 1 illustrates the average of the measured parameters for two seasons, wherein the measured parameters were colour at 420 nm, turbidity at 420 nm, phosphate level, pH and sulphite content of the draft juice (juice from diffuser) and the clarified (clear) juice.
Table 1: Average of the parameters such as colour, turbidity, phosphate level, pH and sulphite content of the draft juice (juice from diffuser) and the clarified (clear) juice measured for two cane seasons.
Seasons Draft Juice (Juice from diffuser) Clear juice % reduction P2O5 (ppm) pH Sulphites (ppm)
Colour at 420 nm Turbidity
at 420 nm Colour at 420 nm Turbidity at 420 nm Colour Turbidity Draft juice Clear juice Draft juice Clear juice Draft juice Clear juice
1st season 16547 36132 11369 1652 31.29 95.43 266 46 5.34 7.01 34 293
2nd season 19619 34026 12313 1423 37.24 95.82 253 37 5.34 7.01 35 323
It was observed that there was around 95% reduction in turbidity, and a 30% to 38% reduction in colour, as the desired values were minimum 90% turbidity reduction at 420 nm and a minimum 30% colour reduction at 420 nm. This study revealed better properties of the clear (clarified) juice.
Table 2 illustrates the average of the measured parameters for two cane seasons, wherein the measured parameters were transmittance at 560 nm, turbidity at 900 nm and pH of the clarified (clear) juice.
Table 2 Average of the parameters such as transmittance, turbidity and pH of the clarified juice measured for two cane seasons.
Transmittance
at 560 nm Turbidity
at 900 nm pH
1st season 53.4 2.0 6.99
2nd season 50.5 2.0 6.99
Desired values Min. 45 – 50% Max. 5.0 ~7
The transmittance, turbidity and pH of the clarified juice were better than desired. The desired value of clarified juice transmittance at 560 nm was a minimum of 45 - 50%, the acceptable clarified juice turbidity at 900 nm was a maximum of 5 and the pH of the clarified juice should be close to 7.00.
Table 3 illustrates the average of the measured parameters for two cane seasons, wherein the measured parameters were Brix, Purity and reducing sugar percentage of the draft juice and the clarified (clear) juice.
Table 3 Average of parameters such as Brix, purity and percentage reducing sugar measured over two cane seasons
Draft juice
(Juice from diffuser) Clarified juice Change in RS% 100 Brix
Brix Purity RS% 100 Brix Brix Purity RS% 100 Brix
1st season 12.23 80.29 5.52 12.77 80.76 4.96 -0.56
2nd season 12.85 81.51 4.72 13.41 81.96 4.36 -0.37
*RS- reducing sugar
Fig. 8 illustrates images of the collected juice samples, wherein Fig. 8a illustrates the juice sample collected from the inlet (800) of the equipment, Fig. 8b illustrates the juice sample collected after the addition of a flocculant, and Fig. 8c illustrates the juice sample collected from the outlet (204) of the equipment of the present disclosure.
Comparative Example 1: Clarification of feed juice by using the equipment of the present disclosure and Louisiana Low Turbulence Clarifier (LLT)
Parallel to the equipment of the present disclosure, another clarifier i.e. a Louisiana Low Turbulence Clarifier (LLT) was run, by using the same feed juice as disclosed in Example 1.
Table 4 illustrates the operating parameters of the equipment of the present disclosure and LLT Clarifier. Table 5 illustrates a comparison of the colour and turbidity of the clarified juices when obtained using the equipment of the present disclosure and LLT clarifier. Table 6 illustrates the results of Brix, purity and reducing sugars of the clarified juices, when obtained by using the equipment of the present disclosure and LLT clarifier.
Table 4 represents of operating parameters of the equipment of the present disclosure and the Louisiana Low Turbulence (LLT) Clarifier
Configuration Draft juice Temperature °C Flocculant
ppm
on Brix Clarified juice Mud
Flow
m3/h Brix Flash
Tank Clear
juice Mud pH Brix Trans%
at 560 nm Turbidity
at 900 nm Solids
%
Equipment of the present disclosure 190.4* 12.20* 105.4* 99.3* 99.1* 31.2* 6.99* 12.74* 53.4* 2.0* 3.42*
7.6# 0.62# 0.5# 0.3# 0.5# 2.0# 0.07# 0.77# 4.2# 0.5# 0.55#
LLT
Clarifier 174.2* 12.29* 105.3* 97.7* 94.4* 28.9* 6.98* 12.81* 51.0* 2.7* 8.65*
15.6# 0.61# 0.5# 0.3# 1.8# 1.1# 0.04# 0.74# 3.2# 0.9# 3.27#
*Average, # Standard deviation
Table 5 represents the comparison of colour and turbidity of the clarified juice when obtained using the equipment of the present disclosure and the LLT Clarifier
Configuration Draft juice Clarified juice %Reduction
Colour
at420 nm Turbidity
at 420 nm Colour
at420 nm Turbidity
at 420 nm Colour Turbidity
Equipment of the present disclosure 16547* 36132* 11369* 1652* 29.23* 95.31*
3487# 7187# 1159# 523# 11.57# 1.70#
LLT
Clarifier 17933* 38920* 11623* 1763* 32.24* 95.30*
5314# 7594# 1284# 536# 11.45# 1.65#
*Average, #P-value
It is concluded from Table 5 that there was a decrease in the colour and turbidity between the draft juice and clarified juice.
Table 6 represents the comparison of the Brix, purity and reducing sugars in the draft juice and the clarified juices, obtained by using the equipment of the present disclosure and the LLT Clarifier
Configuration Draft juice Clarified juice Change
Brix Purity RS%
Brix Brix Purity RS%
Brix Purity RS%
Brix
Equipment of the present disclosure 12.20* 80.29* 5.52* 12.74* 80.76* 4.96* 0.47* -0.56*
0.62# 1.87# 0.60# 0.77# 1.84# 0.47# 0.14# 0.30#
LLT
Clarifier 12.29* 79.68* 5.49* 12.81* 80.03* 5.03* 0.36* -0.45*
0.61# 1.46# 0.73# 0.74# 1.45# 0.66# 0.12# 0.30#
RS - reducing sugar, *Average, #Standard deviation
It is concluded from Table 6 that there is a purity raise in the clarified juice due to the removal of non-sugars and there is a reduction in RS% which are desirable.
Fig. 9a illustrates the percentage transmittance of the clarified juice at 560 nm and Fig. 9b illustrates the turbidity of the clarified juice at 900 nm clarified in the equipment of the present disclosure and LLT clarifier. It is observed that the percentage of transmittance of the clarified juice obtained by using the equipment of the present disclosure was higher than that obtained by using LLT clarifier, as measured at 560 nm for various samples collected at different times. Further, it is observed that the turbidity of the clarified juice obtained by using the equipment of the present disclosure was lower than that obtained by using LLT clarifier, as measured at 900 nm for various samples collected at different times. The equipment of the present disclosure gave a clarified (clear) juice with a higher transmittance, lower turbidity and colour on average, which were desirable. Further, there were no significant differences between any of the operating or performance variables. In nearly all cases, the probability p was < 0.001.
Further, there was little difference in the reducing sugar level from the draft juice to the clarified juice obtained using the equipment of the present application and LTT clarifier, which was desirable. An increase in RS% indicates sucrose loss.
The temperature of the juice in the equipment of the present disclosure was always 99°C+ which was higher than that from the LLT clarifier, which was about 98°C. The temperature of the mud from the equipment was 99°C+, which was higher than that of the LLT clarifier which was from 94 to 97°C indicating that there was a reduction in heat loss upon the use of the equipment of the present disclosure.
Comparative Example 2: Clarification of feed juice in various known clarifiers to measure the retention time
The process of clarification of feed juice was performed by using different continuous clarifiers such as high retention time clarifiers (DorrTM, GraverTM and RapiDorrTM), short retention time clarifiers, low turbulence clarifier, and the equipment of the present disclosure. The results of the juice retention time in various types of clarifiers are as shown in Table 7.
Table 7 represents the comparison and variation in the feed juice retention time in various types of clarifiers.
Sr. No. Type of Juice Clarifier Juice retention time
1 High retention time Clarifiers
(DorrTM, GraverTM and RapiDorrTM) 150 to 180 min
2 Short retention time Clarifiers 45 min
3 Low Turbulence Clarifier 37 min
4 Equipment of the present disclosure 7 min
Continuous clarifiers such as the DorrTM, GraverTM and RapiDorrTM clarifiers are multi-tray, high-retention-time (HRT) clarifiers. A multi-tray clarifier is a large cylindrical tank and is generally divided into 4 to 5-tiered compartments to increase the area of settling. The mud settling distance was about 1 to 1.5m. The residence time of juice in this type of clarifier was about 150 to 180 min. At a Sugar Plant a Graver type clarifier was replaced with a Low Turbulence Clarifier which reduces the juice residence time from 150 min to 37 min.
The equipment of the present disclosure reduced the settling distance for the falling particles to a maximum of 79 mm compared to 1 to 1.5 meters in the conventional clarifiers. The residence time of juice in the equipment of the present disclosure was 7 min which was less than 20% of that of LLT Clarifier. The low residence time reduced the sucrose inversion loss as well as the heat loss across the clarifier.
The equipment of the present disclosure required a very small footprint and the cost to build was very low compared to the conventional clarifier.
In sugar manufacturing, minimizing processing time was important as sucrose loss was directly proportional to the processing time. The equipment of the present disclosure with juice retention time of 7 min was being used for feed juice clarification at full plant scale. The performance of the equipment of the present disclosure, when operated at full plant scale, for juice was better than that of the existing clarifiers.
Comparative Example 3: Clarification of feed juice in various known clarifiers to measure the surface loading rate.
The capacity of any clarifier depends on the surface loading rate (meter/hour), which can be obtained by dividing the liquid flow rate (meter3/hour) by the cross-sectional area (meter2). The average surface loading rate of an SRI (Sugar Research Institute, Australia) trayless clarifier was 4.1 meter/hour, and in RapiDorr clarifiers with four compartments, the surface loading rate was 1.3 meter/hour at full rated capacity. However, a “new generation” clarifier was known to have a surface loading rate of 8.2 meter/hour. Further, for the LLT clarifier, the maximum surface loaded rate known was 7.8 meter/hour. The new generation clarifier is a modified version of SRI using CFD (computational fluid dynamics).
The equipment of the present disclosure was designed for the clarification of feed juice, when operated at a flow rate of 210 tons per hour with a juice retention time of 7 minutes, the surface loading rate obtained was 24 meter/hour based on the lamella bank area. The lamella bank area is the cross-sectional area of the cubical portions of the equipment that contain lamellas.
Comparative Example 4: Clarification of the feed juice in an unmodified lamella clarifier (unmodified equipment) and LLT
In this example, a lamella clarifier having at least one lamella unit at the top portion, wherein inclined plates were arranged in two sets, and a mud cone at the operative bottom portion of the vessel. The lamella clarifier of this example was without mud boot and scraper. The lamella clarifier of comparative example 4 is illustrated in Fig. 7.
The lamella clarifier without mud boot and scraper was operated along with a LLT clarifier. Arrangements were made to feed the juice to one or both clarifiers after the flash tank. A flow control was arranged at the lamella clarifier juice inlet in such a way that a set quantity of juice was allowed into the lamella clarifier without mud boot and the rest of the juice went into the existing LLT clarifier. View glasses and sampling points were arranged in the conical unit (bottom conical portion of the vessel) of the lamella clarifier to monitor the mud level. Mud withdrawal from the clarifier was controlled with a flow meter and variable frequency drive pump.
Preparation of the feed juice: In the sugar industry, sugarcane was prepared and then juice was extracted by means of milling or diffusion. In milling, juice was extracted by pressing the cane, whereas in diffuser, the juice was extracted on systematic counter current washing of the cane by means of hot water. In practice, this was achieved by forming a bed of shredded cane on a conveyor. Hot water was evenly sprayed at the discharge end of the conveyor and percolated through the bed of bagasse and the perforated slots of the conveyor. The hot water dissolved the sugar in the bagasse and the thin juice thus formed was collected in a hopper. This juice was moved forward one stage by pumping and the process was repeated until the juice reached maximum concentration at the feed end of the diffuser.
The juice leaving the diffuser was treated with lime and SO2 gas and heated in three stages to a temperature of 105°C before the juice entered the flash tank. The flashed juice or feed juice entered the lamella unit of the lamella clarifier from where it was distributed to the banks of two sets of inclined plates. A flocculant was added before the feed chamber using an inline distributor. The clarified juice from the top of the lamella clarifier vessel was routed to a clear juice tank.
After routine checks with water, the lamella clarifier was taken into service. The feeding rate of the feed juice was gradually increased in stages to 150 meter3/hour. The flocculant dosing rate was set at 5 ppm on cane. Mud withdrawal from the lamella juice clarifier was set to control a mud flow rate of 4% on juice flow. As the clear (clarified) juice quality was good, the entire juice was diverted to the lamella clarifier and the LLT clarifier was stopped.
(5 ppm on cane means for 100 MT of cane flocculant used was 100*5/1000000 = 0.0005 MT = 0.5 Kg)
(32 ppm on brix means for 100 MT cane @15 brix%, flocculant used was 100*0.15*32/1000000 = 0.00048 MT = 0.48 Kg.)
The quality of clear juice from the lamella clarifier was found to be satisfactory. However, the mud from the two sampling points at the bottom of the lamella clarifier was always thin compared to that from the top two sampling points. Thin mud increased the juice recirculation and affected the performance of the vacuum filter. After 3 days of operation, the carryover of mud particles in clear juice was noticed. The lamella clarifier was stopped and liquidated. Mud accumulation was found in the mud cone up to 500 mm below the inclined plates. Mud was also settled on the top side of the perforated plate of the juice outlet. The clarifier was then washed with a pressure jet pump.
The perforated plates were placed on the top side of the unmodified equipment. The perforated plates had equally distributed perforations to withdraw the clear juice from the entire cross section of the clarifier so as to ensure that there are no dead pockets and no short circuits in the clarifier.
Modification 1:
Due to the regular need for mud withdrawal, the following modifications were carried out in the lamella clarifier (equipment):
o Mud outlet nozzle and mud pumps suction line size was increased from 4 inches to 6 inches (i.e., 10.16 cm to 15.24 cm).
o The mud flow meter was changed. An electronic flow meter was replaced with a micro-processed based flow meter which was highly efficient.
o Centrifugal pumps were replaced with positive displacement screw pumps for mud withdrawal. The advantages of a screw pump over a centrifugal pump were low internal velocity, very low pulsation, constant flow rate and the like. In a screw pump, as the screw rotates the fluid passed steadily and there would not be any mud particle breakage.
o Variable frequency drives (VFDs) were arranged to ensure uniform and continuous withdrawal of mud from the clarifier. A variable frequency drive (VFD) is a type of motor controller that drives an electric motor by varying the frequency and voltage of its power supply. VFD was used for required and steady mud flow.
o Inline temperature indicators with a recording arrangement were made for both clear juice and mud.
After these modifications, the equipment (lamella clarifier) was put into use. The equipment was operated continuously at a juice inlet flow rate of 100 meter3/hour and a mud flow of 4.0 meter3/hour. However, the problem of thin mud continued and mud in the lower sampling points was thinner than that from upper sampling points, which was not desired. After 2 days of operation, carryover of mud particles in clear juice started. This was due to uneven mud discharge in the equipment mud layer causing loose mud to be withdrawn and building up of mud on the cone up to the square to round transition height and starting carryover of mud particles into the clear juice.
Modification 2:
To overcome this problem in the mud layer, a rotating scraper was added in the conical portion of the vessel to operate at 3.7 revolutions per hour. This arrangement of the scraper was possible because the lamellas (inclined plates) were arranged as two sets. After installing the scraper, the clarifier was put into use at a juice feed rate of 100 meter3/hour. Mud samples were analyzed for percentage solid content and recorded. The quality of clear (clarified) juice from the equipment was good and similar to that from the LLT clarifier. There was an improvement in the percentage mud solids content but still mud withdrawn was thinner than the mud from the bottom sampling points, which was undesired.
Performance of the equipment was observed at different juice feed rates for some hours and finally, the entire juice was diverted to the equipment. The equipment was operated continuously until the plant stopped for cleaning on the 5th day.
It was observed that the equipment of the present disclosure provided the desired outcome when the equipment was designed and operated using the parameters of Example 1.
TECHNICAL ADVANCEMENTS
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of, equipment for the clarification of a feed juice:
• can be easily scaled up, requires a small footprint area, increased productivity, consistent product quality, high process flexibility, reduced capital, and operating cost;
• has a simple and compact design, with a low capital cost;
• requires low residence time for the clarification of the feed juice, which reduces the inversion loss as well as the heat loss across the equipment; ultimately resulting in a more efficient clarification process; and
• the operating volume of the equipment is lower, which makes the liquidation process much easier and quicker.
and
a process for the clarification of the feed juice that:
• is simple and efficient; and
• requires less retention time for the juice.
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.
The foregoing description of the specific embodiments 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.
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.
Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
The numerical values mentioned for the various physical parameters, dimensions or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the disclosure, unless there is a statement in the specification specific to the contrary.
While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation. 
, Claims:WE CLAIM:
1. An equipment (1000) for the clarification of feed juice, said equipment comprising:
(a) a flash tank (100) for receiving unclarified feed juice and removing entrapped gases from said unclarified feed juice by flashing to obtain a flashed unclarified feed juice first stream;
(b) a vessel (200) for receiving the first stream of flashed unclarified feed juice and separating the received first stream into a second stream of clarified juice and a third stream containing semi-solid mud slurry; said vessel (200) comprising:
i. an operative bottom section of said vessel (200) having a conical unit (500) for receiving said first stream of flashed unclarified feed rich in solid particles through an operative top section of said vessel (200) and configured to allow solid particles in said first stream to settle as semi-solid mud slurry at the base of said bottom section and further configured to allow said first stream with reduced solid particles to rise up at the top of said conical unit (500);
ii. said operative top section of said vessel (200) having at least one lamella unit (400) configured to receive said first stream with reduced solid particles from the top of said conical unit (500) and clarify said first stream to obtain said second stream of clarified juice from a clear juice outlet (204); and
iii. a mud boot (600) arranged below said conical unit (500) to receive and discharge said semi-solid mud slurry as a third stream;
characterized in that said equipment (1000) further comprises,
a scraper (700) having scraping elements at extremities, said scraper (700) having a shaft drive (702) mounted on a support (202) attached to an operative top side of said vessel (200) and configured to extend to said mud boot (600), said scraper (700) configured to be rotatably driven about an operative vertical axis of said vessel (200) to remove deposits of semi-solid mud slurry from the inner surfaces of said conical unit (500) and said mud boot (600) by a scraping action.
2. The equipment as claimed in claim 1, wherein said mud boot (600) is configured to have an operative top portion having cylindrical geometry (602) of a diameter to height ratio in the range of 1:1 to 1.5:1; and said mud boot (600) is further configured to have an operative bottom portion being in the shape of a frustum of a cone (604) making an angle with a vertical axis in the range of 40 degrees to 50 degrees.
3. The equipment as claimed in claim 1, wherein said mud boot (600) is configured with a mud boot outlet nozzle (606) at an operative bottom side of said mud boot (600), said mud boot outlet nozzle (606) being configured to withdraw the third stream containing semi-solid mud slurry through said operative bottom side of said mud boot (600).
4. The equipment as claimed in claim 1, wherein said lamella unit (400) is configured to have plurality of inclined plates (402) arranged in two adjacent sets (402’, 402”) and at least one channel (401) formed by side walls of two adjacent sets (402’, 402”); said plurality of inclined plates (402) configured at an inclination to a vertical axis of said vessel (200), the inclination being in the range of 25 degrees to 35 degrees.
5. The equipment as claimed in claim 4, wherein said plurality of inclined plates (402) are arranged in parallel, and interspaced with a distance in the range of 25 mm to 75 mm; and said inclined plates having a thickness in the range of 2 mm to 10 mm.
6. The equipment as claimed in claim 1, wherein said lamella unit (400) fluidly connected with said mud boot (600) and the clear juice outlet (204), said lamella unit (400) is further configured to receive the flashed unclarified feed juice through at least one channel (401) and separate the flashed unclarified feed juice in a clarified form as the second stream being transported to said clear juice outlet (204) while the remaining portion including semi-solid mud slurry is transported to the mud boot (600).
7. The equipment as claimed in claim 1, wherein said scraper (700) includes at least one scraper arm (704) in said conical unit (500) and at least one mud boot scraper arm (706), wherein
• said at least one scraper arm (704) and said at least one mud boot scraper arm (706) being attached to said shaft drive (702);
• said at least one scraper arm (704) configured to remove said semi-solid mud slurry from the inner surface of said conical unit (500); and
• said mud boot scraper arm (706) is configured to remove said semi-solid mud slurry from the inner surface of said mud boot (600).
8. The equipment as claimed in claim 1, wherein said shaft drive (702) is supported on said operative bottom portion of said mud boot (600) through a shaft support (708).
9. The equipment as claimed in claim 1, wherein said conical unit (500) is configured at said operative bottom section of said vessel (200) has a shape of a frustum of a cone having an angle with a vertical axis in the range of 25 degrees to 35 degrees.
10. The equipment as claimed in claim 1, wherein said lamella unit (400) and said conical unit (500) have different operative height dimensions, the ratio of the height of said lamella unit (400) to the height of said conical unit (500) being in the range of 1:2 to 1:2.5.
11. The equipment as claimed in claim 1, wherein said vessel (200) receives said first stream of flashed unclarified feed juice through a feed inlet pipe (800), said feed inlet pipe (800) has a first end and a second end, wherein
• said first end is fluidly connected to an operative bottom portion of said flash tank (100), and
• said second end is fluidly connected to said operative top section of said vessel (200);
said feed inlet pipe (800) is configured to receive said flashed unclarified feed juice from said flash tank (100).
12. The equipment as claimed in claim 11, wherein said feed inlet pipe (800) includes a flocculant adding point (804) from an automatic flocculant dosing system, said flocculant adding point (804) configured to feed a flocculant to said flashed unclarified feed juice in said feed inlet pipe (800).
13. The equipment as claimed in claim 12, wherein said feed inlet pipe (800) is in fluid communication with a distributor (802) and said distributor (802) is configured to distribute said flashed unclarified feed juice from said feed inlet pipe (800) to at least one channel (401) formed by two adjacent sets (402’, 402”) of plurality of inclined plates (402) of the lamella unit (400).
14. The equipment as claimed in claim 1, wherein said conical unit (500) at said operative bottom section of said vessel (200) is configured to have at least six mud sampling ports (502) to monitor the mud level at different points within the vessel (200).
15. The equipment as claimed in claim 1, wherein said vessel (200) attached with a plurality of sensors (900), said plurality of sensors (900) are selected from the group consisting of a pH sensor, a temperature sensor, a turbidity sensor, and a colour sensor.
16. A process for the clarification of a feed juice, said process comprising the following steps:
• receiving an unclarified feed juice having a predetermined temperature in a flash tank (100) for flashing to obtain a flashed unclarified feed juice first stream;
• adding a predetermined amount of flocculant to said flashed unclarified feed juice received from the flash tank (100) to obtain a feed mixture having said flashed unclarified feed juice;
• distributing said feed mixture to an operative bottom section of vessel (200) at a first predetermined flow rate through at least one channel (401) of lamella unit (400) by maintaining a predetermined surface loading rate to obtain semi-solid mud slurry at said operative bottom section at a predetermined rate of mud settling and a juice with reduced semi-solid mud at the top surface of a conical unit (500);
• allowing separation of said juice with reduced semi-solid mud slurry at the top surface of said conical unit (500) through the transportation from two sets (402’, 402”) of a plurality of inclined plates of said lamella unit (400) to obtain clarified juice at the outlet (204) in a predetermined time period and settling further said semi-solid mud slurry at said operative bottom section;
• scraping said semi-solid mud slurry from said operative bottom section of vessel (200) having said conical unit (500) and a mud boot (600) of the vessel (200) by using a scraper (700) rotating at a predetermined speed;
• discharging said semi-solid mud slurry scraped from said operative bottom section at a second predetermined flow rate through a mud boot outlet nozzle (606) as a third stream; and
• collecting said clarified juice as a second stream from a clear juice outlet (204) of said vessel (200).
17. The process as claimed in claim 16, wherein said predetermined temperature of unclarified feed juice is in the range of 102 C to 106 C.
18. The process as claimed in claim 16, wherein said first predetermined flow rate of said feed mixture to the vessel is in the range of 150 tons per hour to 250 tons per hour.
19. The process as claimed in claim 16, wherein said predetermined amount of said flocculant is in the range of 2 ppm on cane to 6 ppm on cane.
20. The process as claimed in claim 16, wherein said predetermined surface loading rate is in the range of 20 meters per hour to 30 meters per hour.
21. The process as claimed in claim 16, wherein said predetermined time period of obtaining clarified juice is in the range of 5 minutes to 10 minutes.
22. The process as claimed in claim 16, wherein said rotating speed of said scraper is in the range of 2 to 5 rotations per hour.
23. The process as claimed in claim 16, wherein said second predetermined flow rate of discharging the semi-solid mud slurry is in the range of 9 metric tons per hour to 15 metric tons per hour.
24. The process as claimed in claim 16, wherein said predetermined mud settling rate inside said vessel is in the range of 250 mm per minute to 350 mm per minute.

Dated this 22nd Day of November, 2024

_______________________________
MOHAN RAJKUMAR DEWAN, IN/PA – 25
OF R. K. DEWAN & CO.
AUTHORIZED AGENT OF APPLICANT

TO,
THE CONTROLLER OF PATENTS
THE PATENT OFFICE, AT CHENNAI