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 to, indicates otherwise.
Brix: The term "brix" refers to a measurement of the sugar concentration in a liquid solution, expressed as the percentage by weight of sugar. For example, a solution with 20° brix contains 20 grams of sugar per 100 grams of solution.
Clarifier: The term “clarifier” refers to equipment that is used to perform the clarification process.
Flocculant: The term “flocculant” refers to a substance which promotes the coagulation of particles in a liquid.
Flotation Clarification: The term “flotation clarification” refers to a process in which very fine suspended matter is agglomerated and floated to the surface by fine air bubbles. The flotation clarification has been used in water treatment and in the mineral processing industry for the separation of suspended solids.
Lamella Clarifier: The term “lamella clarifier” refers to a compact, inclined plate type of clarifier, which is conventionally used for clarification of water, wastewater and liquid having suspended and colloidal particles. The lamella clarifier provides a number of inclined plates to give a large projected surface area. The lamella clarifier consists of a series of inclined overlapping plates, which are arranged to form a separate chamber or the cells between each pair of adjacent plates.
Pretreated syrup: The term “pretreated syrup” refers to sugarcane syrup that has been heated and treated with lime saccharate and phosphoric acid. During this process, air is dissolved into the syrup, and a flocculant is added.
Raw syrup: The term “raw syrup” refers to a concentrated sugar solution that is made by boiling clarified sugarcane juice in multiple effect evaporators to remove water.
Scraper: The term “scraper” refers to a part that is used to scrap the semi-solid mud or precipitate or scum which floats on the top surface of the clarifier.
Surface loading rate: The term “surface loading rate” refers to a parameter used to measure the capacity and efficiency of a clarifier unit. It is expressed in meters per hour (m/hr) and can be calculated by dividing the liquid flow rate (m3/hr) by the cross-sectional area (m2).
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.
Sugarcane, is also known as “Saccharum officinarum”. Sugarcane is a species of tall, perennial grass that is used for sugar production. Sugarcane is grown in tropical and sub-tropical regions of the world. The plants are 2 to 6 meters tall with stout, jointed, fibrous stalks that are rich in sucrose which accumulates in the stalk internodes. Sugarcane accounts for 79% of sugar produced globally. The average annual production of sugarcane in India is 35 crore tons.
Sugar syrup is a highly viscous and denser liquid that is obtained by the evaporative process of the sugarcane clarified juice. However, some suspended material may remain in the clarified juice during periods of upset and mud carryover. Further, there is a huge increase in turbidity by about 80% across the evaporators. Turbidity of the syrup hinders the downstream sugar-making operations such as crystallization, centrifugation and the like. Higher turbidity of the syrup also affects the final product (sugar) quality.
Conventionally, a circular syrup clarifier is used, in which the sugarcane syrup is heated to 80oC and then treated with lime saccharate and phosphoric acid. Air is dissolved in the syrup by using a Dissolved Air Flotation unit before feeding to the clarifier. The residence time of syrup for this conventional clarifier is high, which is around 20 minutes. Further, the conventional clarifiers require a large footprint area, and a high cost to build. There is always a need for a clarifier that provides reduced residence time and is efficient.
Therefore, there is felt a need for equipment and a process for clarification of the syrup 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 a process for the clarification of syrup with a relatively low retention time.
Still another object of the present disclosure is to provide equipment for the clarification of syrup with high surface loading rates.
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 a process for the clarification of syrup, the process comprises introducing a pretreated syrup containing a flocculant at a predetermined temperature and a predetermined flow rate to a vessel through an inlet of equipment operating at a predetermined surface loading rate, in which the inlet is located at an operative middle section of the vessel. The pretreated syrup is allowed to flow over a plurality of inclined plates in a downward direction within the vessel to separate the pretreated syrup into a clarified syrup and a floating scum. The floating scum is scraped from an operative top section of the vessel by using a plurality of scrapers moving at a predetermined speed. The scraped scum is continuously removed from the vessel through a scum outlet while maintaining a predetermined thickness of a scum layer at the operative top section and discharging the clarified syrup from a clarified syrup outlet. The clarified syrup outlet is connected to an operative bottom section in a predetermined time period.
In accordance with the present disclosure, the predetermined temperature is in the range of 75 oC to 85 oC.
In accordance with the present disclosure, the predetermined flow rate is in the range of 30 tons per hour to 60 tons per hour.
In accordance with the present disclosure, the predetermined speed of the scraper is in the range of 0.5 meter/minute to 1 meter/minute.
In accordance with the present disclosure, the predetermined thickness of the scum layer is in the range of 75 mm to 125 mm.
In accordance with the present disclosure, the predetermined time period is in the range of 5 minutes to 15 minutes.
In accordance with the present disclosure, the predetermined surface loading rate is in the range of 5 meters per hour to 15 meters per hour.
The present disclosure further relates to equipment for the clarification of syrup, the equipment comprises a vessel and a plurality of scrapers. The vessel includes an inlet at an operative middle section of the vessel configured to receive a pretreated syrup; a plurality of inclined plates attached within the vessel at the operative middle section configured to distribute the pretreated syrup over the inclined plates and further configured to separate the pretreated syrup into a clarified syrup and a floating scum; and a clarified syrup outlet at an operative bottom section configured to withdraw the clarified syrup. The plurality of scrapers are mounted on an operative top of the vessel. The scrapers are configured to be driven by a motor and move along a horizontal axis to scrap the floating scum from a top operative section of the vessel and discharge the scum through a scum outlet.
In accordance with the present disclosure, the equipment further comprises a perforated base configured to partition the vessel into the operative middle section and the operative bottom section.
In accordance with the present disclosure, the plurality of inclined plates are arranged in parallel and interspaced at a distance in the range of 25 mm to 75 mm from each other.
In accordance with the present disclosure, the plurality of inclined plates has a thickness in the range of 2 mm to 10 mm, a height in the range of 1000 mm to 1500 mm, and a width in the range of 1200 mm to 1700 mm.
In accordance with the present disclosure, the plurality of inclined plates has a count in the range of 30 plates to 80 plates.
In accordance with the present disclosure, the plurality of inclined plates are provided with a plurality of guide plates to hold the inclined plates at an angle in the range of 25 degrees to 35 degrees with respect to a vertical axis of the vessel.
In accordance with the present disclosure, the clarified syrup outlet is fluidly connected to a box, the box containing a telescopic valve, wherein the height of the telescopic valve is adjustable to maintain the required scum thickness in the vessel.
In accordance with the present disclosure, the vessel is configured with a plurality of sensors, the plurality of sensors selected from the group consisting of pH sensor, temperature sensor, turbidity sensor and color sensor.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
The present disclosure will now be described with the help of the accompanying drawing, in which:
Fig. 1(a)illustrates a 3D view of equipment (1000) in accordance with the present disclosure;
Fig. 1(b) illustrates a 3D right side view of the equipment (1000) in accordance with the present disclosure;
Fig. 1(c) illustrates a 3D elevation view of the equipment (1000) in accordance with the present disclosure;
Fig. 1(d) illustrates a 3D left side view of the equipment (1000) in accordance with the present disclosure;
Fig. 1(e) illustrates a 3D top view of the equipment (1000) in accordance with the present disclosure;
Fig.2 illustrates an actual image of the equipment (1000) in accordance with the present disclosure;
Fig.3 illustrates a line diagram of flow of syrup, clear syrup and scum in the equipment (1000) in accordance with the present disclosure;
Fig.4 illustrates an arrangement of a plurality of inclined plates in the equipment (1000) in accordance with the present disclosure;
Fig.5 illustrates a clear syrup from a clarified syrup outlet of the equipment (1000) in accordance with the present disclosure;
Fig.6 illustrates a scum discharging from a scum outlet of the equipment (1000) in accordance with the present disclosure; and
Fig.7 illustrates the graphs comparing the turbidity at 900 nm of clear syrup samples collected at different times obtained by using a conventional clarifier and the equipment (lamella clarifier) of the present disclosure.
LIST OF REFERENCE NUMERALS
Reference numerals Description
1000 Equipment in accordance with the present disclosure
100 Vessel
105 Structure for support (not shown in the figure)
110 Inlet for pretreated syrup
120 Plurality of inclined plates
123 Plurality of guide plates
125 Perforated base
130 Operative top section of the vessel
140 Plurality of scrapers
150 Motor (scraper drive)
160 Operative top
170 Operative bottom section of the vessel
180 Clarified syrup outlet
190 Scum outlet
200 Plurality of sensors (not shown in figure)
210 Manhole
220 Inclined wall
230 A box containing clarified syrup outlet telescopic valve
240 Plurality of sight glass
250 Dissolved air flotation unit (DAF) (not shown in the figure)
DETAILED DESCRIPTION
The present disclosure relates to industrial processing technologies.
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 apparatus 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.
Sugar syrup is a highly viscous and denser liquid that is obtained by the evaporative process of the sugarcane clarified juice. However, some suspended material may remain there in the clarified juice during periods of upset and mud carryover. Further, there is a huge increase in turbidity by about 80% across the evaporators. Turbidity of the syrup hinders the downstream sugar-making operations such as crystallization, centrifugation and the like. Higher turbidity of the syrup also affects the final product (sugar) quality.
Conventionally, a circular syrup clarifier is used, in which the sugarcane syrup is heated to 80 oC and then treated with lime saccharate and phosphoric acid. Air is dissolved in the syrup using a Dissolved Air Flotation system before feeding to the clarifier. The residence time of syrup for this conventional clarifier is high, which is around 20 minutes.
However, conventional clarifiers require a large footprint area and a high cost to build. There is always a need of a clarifier that has reduced residence time and is efficient.
In an aspect, the present disclosure provides equipment (1000) for the clarification of syrup.
Referring to Fig. 1 to Fig. 4, the equipment (1000) for the clarification of the syrup is described.
The equipment comprises a vessel (100) and a plurality of scrapers (140). The vessel (100) includes an inlet (110), a plurality of inclined plates (120) and a clarified syrup outlet (180). The inlet (110) is located at an operative middle section of the vessel (100). The inlet (110) is configured to receive a pretreated syrup. The plurality of inclined plates (120) are attached within the vessel (100) at the operative middle section. The plurality of inclined plates (120) are configured to distribute the pretreated syrup over the inclined plates (120) and further configured to separate the pretreated syrup into a clarified syrup and a floating scum. The clarified syrup outlet (180) is located at an operative bottom section (170). The clarified syrup outlet (180) is configured to withdraw the clarified syrup. The plurality of scrapers (140) are mounted on an operative top (160) of the vessel (100). The scrapers (140) are configured to be driven by a motor (150) rotating around a horizontal axis. The motor (150) moves and rotates a conveyor over the operative top (160). The scrapers (140) move along with the conveyor along a horizontal axis to scrap the floating scum from an operative top section (130) of the vessel and discharge the scum through a scum outlet (190).
In accordance with the embodiments of the present disclosure, the equipment further comprises a perforated base (125) configured to partition the vessel (100) into the operative middle section and the operative bottom section (170). The purpose of the perforated base is to ensure uniform withdrawal of the clear syrup from the entire cross-section area of the clarifier.
In accordance with the embodiments of the present disclosure, the vessel (100) has at least one inclined wall (220), and the vessel (100) is further configured to attach the plurality of inclined plates (120) arranged at an inclination to a vertical axis of the vessel (100), the inclination being in the range of 25 degrees to 35 degrees. In an exemplary embodiment, the inclination of the plates is 30 degrees with respect to the vertical axis of the vessel.
In accordance with the embodiments of the present disclosure, the plurality of inclined plates (120) are arranged in parallel and interspaced at a distance in the range of 25 mm to 75 mm from each other. In an exemplary embodiment, the plurality of inclined plates (120) are arranged in parallel and interspaced at a distance of 59 mm from each other.
In accordance with the embodiments of the present disclosure, the plurality of inclined plates (120) have a thickness in the range of 2 mm to 10 mm, a height in the range of 1000 mm to 1500 mm, and a width in the range of 1200 mm to 1700 mm. In an exemplary embodiment, the plurality of inclined plates (120) has a thickness of 3 mm, a height of 1219 mm, and a width of 1524 mm. The dimensions of the plates are variable as per the requirement.
In accordance with the embodiments of the present disclosure, the plurality of inclined plates (120) have a count in the range of 30 plates to 80 plates. In an exemplary embodiment, the vessel (100) has 55 inclined plates.
In accordance with the embodiments of the present disclosure, the inlet (110) is in fluid communication with the top portion of the inclined plates (120) to introduce pretreated syrup.
In accordance with an embodiment of the present disclosure, the plurality of inclined plates (120) are cold rolled, heat treated, pickle and skin passed (2B surface finish), which affects the surface smoothness of the plates.
In accordance with the embodiments of the present disclosure, the plurality of inclined plates (120) are provided with a plurality of guide plates (123) to hold the inclined plates at an angle in the range of 25 degrees to 35 degrees with respect to a vertical axis, as shown in Fig. 4.
In accordance with the embodiments of the present disclosure, the plurality of scrapers (140) mounted on an operative top (160) of the vessel (100), are configured to transport the floating scum to the scum outlet (190). The scum is discharged from the scum outlet (190).
In accordance with the embodiments of the present disclosure, the scum is discharged from the scum outlet (190)and is transferred to a diffuser for further recovery of sugar from it.
In accordance with the embodiments of the present disclosure, the operative top section (130) of the vessel (100) has a rectangular profile.
In accordance with the embodiments of the present disclosure, the equipment (1000) performs a clarification process of syrup.
In accordance with the embodiments of the present disclosure, the equipment (1000) is attached to an automatic dosing unit for feeding a fluid selected from the group of an aqueous acid, an aqueous base, and a flocculant.
In accordance with the present disclosure, the flocculants are very high molecular weight polymers, available in powder and emulsion form. To ensure the efficiency of the clarification process, the preparation of the dilute polymer solution is critical. The automatic dosing system prepares flocculant solutions. The automatic dosing system contains baffles that allow the circulation of the polymer preparation through a series of compartments. This ensures an optimum reaction time in each compartment and maintains a continuous concentration level, thereby avoiding any extra route between a preparation compartment and a dosing solution compartment.
The automatic dosing unit is automated by a control panel connected to an 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 automatic dosing unit has numerous advantages such as the automatic dosing unit avoids the need for manual operations and monitors homogeneity in flocculant concentration which prevents dosing errors, and operation stops. The high-efficiency mixers of the automatic dosing unit facilitate a low flow mixing for a homogeneous flocculant polymerization without mechanical deterioration. The automatic dosing unit is an intelligent system that is regulated by an ultrasonic level switch, making the system reliable and robust.
In accordance with the embodiments of the present disclosure, the clarified syrup outlet (180) is fluidly connected to a box (230), the box (230) containing a telescopic valve, wherein the height of the telescopic valve is adjustable to maintain the required scum thickness in the vessel(100).
In accordance with an embodiment of the present disclosure, the height of the clarified syrup outlet (180) is adjustable with respect to the operative bottom section (170) of the vessel (100), based on scum thickness on the operative top section (130) of the vessel (100).
In accordance with the embodiments of the present disclosure, the vessel (100) is configured with a plurality of sensors (200), the plurality of sensors (200) selected from the group of pH sensor, temperature sensor, turbidity sensor and color sensor.
In accordance with the embodiments of the present disclosure, the vessel (100) is attached to three temperature sensors. The first temperature sensor is placed at an inlet (110). The second temperature sensor is placed at the clarified syrup outlet (180). The third temperature sensor is placed at the scum outlet (190).
In accordance with the embodiments of the present disclosure, the vessel (100) has plurality of sight glasses (240) on the wall surface to monitor the scum formation.
In accordance with the embodiments of the present disclosure, the equipment (1000) consists of a heat exchanger to maintain the temperature of the pretreated syrup at around 80 oC.
In the clarification process of the present disclosure, the very fine suspended matter is agglomerated and floated on the surface by fine air bubbles and the clarified syrup is drawn towards the bottom.
During clarification, scum separation from the liquid works on the principle of difference in density. In the settling clarifier, mud settles to the bottom as it is denser than the liquid, conversely, in the flotation type clarifier mud or scum floats to the top as it is lighter than the liquid. The equipment of the present disclosure works on the principle of flotation type clarifier.
In accordance with the embodiments of the present disclosure, the vessel (100) is attached with a dissolved air flotation unit (DAF) (250) to dissolve air into the pretreated syrup. In an embodiment, the air is dissolved in the pretreated syrup at a pressure in the range of 450 kPa to 500 kPa.
In sugar manufacturing, minimizing the processing time is important as sucrose loss is directly proportional to the processing time.
The equipment of the present disclosure is operable at full plant scale the clarification of the syrup. The performance of the equipment of the present disclosure is better compared to a conventional clarifier. The equipment of the present disclosure has a simple and compact design and has a low capital cost.
The low residence time reduces the inversion loss as well as the heat loss across the clarifiers, ultimately resulting in a more efficient clarification. The lower operating volume of the equipment of the present disclosure makes the liquidation process much easier and quicker.
When the sugar plant stops for more than 8 hours for any reason, it is necessary to liquidate the clarifier to prevent the syrup from spoiling. The time required for the 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.
Operating volume of the equipment is lower, which makes the liquidation process much easier and quicker.
The equipment is designed, manufactured and installed for the clarification of syrup by flotation process. The design follows the arrangement with the treated syrup entering to inclined plates from the top, and the clarified syrup being withdrawn from the bottom of the inclined plates. Clear syrup flows out through a telescopic valve, the height of which can be adjusted to achieve the required scum (semi-solid mud) layer thickness. The scum is removed from the top surface using a horizontally moving scraper. The suspended solids from the syrup are separated deliberately by floatation technique and this process is called syrup clarification.
In another aspect, the present disclosure provides a process for the clarification of syrup.
Referring to Fig.3, the process is described in detail.
A pretreated syrup containing a flocculant is introduced at a predetermined temperature and a predetermined flow rate to a vessel (100) through an inlet (110) of equipment (1000)operating at a predetermined surface loading rate; wherein the inlet (110) is located at an operative middle section.
In accordance with the embodiments of the present disclosure, the predetermined temperature is in the range of 75oC to 85oC. In an exemplary embodiment, the predetermined temperature is 80oC.
In accordance with the embodiments of the present disclosure, the predetermined flow rate is in the range of 30 tons per hour to 60 tons per hour. In an exemplary embodiment, the predetermined flow rate is 55 tons per hour.
In accordance with the embodiments of the present disclosure, the predetermined surface loading rate is in the range of 5 meters per hour to 15 meters per hour. In an exemplary embodiment, the predetermined surface loading rate is 10.38 meters per hour.
The pretreated syrup is allowed to flow over a plurality of inclined plates (120) in a downward direction within the vessel (100) to separate the pretreated syrup into a clarified syrup and a floating scum.
The floating scum is scraped from an operative top section (130) of the vessel (100) by using a plurality of scrapers (140) moving at a predetermined speed.
In accordance with the embodiments of the present disclosure, the predetermined speed of the scraper (140) is in the range of 0.5 meters/minute to 1 meter/minute. In an exemplary embodiment, the predetermined speed of the scraper is 0.85 meters/minute.
In accordance with an embodiment of the present disclosure, the plurality of scrapers (140) moves in a horizontal direction over the top of the vessel and creates a rotational movement.
The scraped scum is continuously removed from the vessel (100) through a scum outlet (190) while maintaining a predetermined thickness of the scum layer at the operative top section (130).
In accordance with the embodiments of the present disclosure, the thickness of the scum is in the range of 75 mm to 125 mm. In an exemplary embodiment, the predetermined thickness of the scum is 100 mm.
The clarified syrup is discharged from a clarified syrup outlet (180) connected to an operative bottom section (170) in a predetermined time period.
In accordance with the embodiments of the present disclosure, the predetermined time period is in the range of 5 minutes to 15 minutes. In an exemplary embodiment, the predetermined time period is 9 minutes.
In accordance with the embodiments of the present disclosure, air is dissolved in the pretreated syrup in a pressure vessel at a pressure in the range of 450 kPa to 500 kPa. In an exemplary embodiment, air is dissolved in the pretreated syrup in a pressure vessel at a pressure of 475 kPa.
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.
EXPERIMENTAL DETAILS:
Example 1: A process for clarification of a pretreated syrup by using the equipment of the present disclosure
Syrup is a highly viscous and denser liquid that is obtained by the evaporative process of the sugarcane clarified juice.
A pretreated syrup mixed with a flocculant (polyacrylamide)was introduced to a vessel (100) at a flow rate of 55 tons/hour while maintaining the temperature at 80 C. The pretreated syrup with the flocculant was distributed over a plurality of inclined plates (120) to obtain a clarified syrup in 9 minutes. A floating scum separated from the pretreated syrup was scraped from an operative top section (130) of the vessel (100) by using a plurality of scrapers (140) moving at a speed of 0.85 meter/minute. The floating scum separated from the pretreated syrup was removed from the vessel (100) continuously from a scum outlet (190) while maintaining a thickness of scum layer of 90 mm to 100 mm at an operative top section (130). The clarified syrup was discharged from an outlet (180) from the vessel (100). The surface loading rate of the equipment was 10.38 meter per hour.
The flocculant used was a high molecular weight poly acryl amide which enhanced the coagulation process. It was in solid form and used in the clarification process after diluting in warm water to a concentration of 0.05% w/v.
The equipment consisted of 55 inclined plates (120) of 1524 mm wide x 1219 mm height x 3 mm thick at an inclination of 30° with the vertical axis of the vessel (100) and the plurality of inclined plates (120) were arranged in parallel and interspaced at a distanceof59 mm.
The syrup retention time in the equipment of the present disclosure was 9 minutes.
In sugar manufacturing, minimizing the processing time (retention time) is important as sucrose loss is directly proportional to the processing time. By using the equipment and the process for the clarification of syrup of the present disclosure, a minimum processing time of 9 minutes was achieved.
Further, the equipment of the present disclosure was run for two cane seasons in accordance with the process of the present disclosure.
The pH, turbidity, transmittance and conductivity ash% were measured for raw syrup and clear syrup. The raw syrup used was the syrup obtained from the evaporator. The results are shown in Table 1.
Table 1Average of the parameters such as pH, turbidity, transmittance and conductivity ash% of the raw syrup and clarified syrup measured for two cane seasons
Season pH Turbidity at 900 nm Transmittance at 560 nm Conductivity
ash %
Raw syrup Clear syrup Raw syrup Clear syrup Percent reduction Raw syrup Clear syrup Raw syrup Clear syrup
Season I 6.52 6.35 329.27 140.54 57.32 5.3 7.8 2.06 1.96
Season II 6.42 6.32 364.3 149.0 59.11 5.1 7.2 2.06 1.97
*Season I was from 13.12.2021 to 04.02.2022, and season II was from 24.12.2022 to 23.02.2023
It can be observed from Table 1 that there was more than a 50% reduction in the turbidity of the syrup when measured at 900 nm. The transmittance of the syrup was improved and the ash conductivity percentage was reduced. The acidic pH of the syrup was deliberately maintained, as an increase in pH will negatively affect the sugar quality. It is further reduced to 4.8 to 5.0 pH by sulphitation before sending it to the crystallization process.
Fig.5 shows an image of the clarified syrup and Fig.6 shows an image of the scum flow to the outlet (190).
The equipment of the present disclosure can run continuously for the entire cane season in a year, with occasional maintenance.
The pretreated syrup was obtained after treating the raw syrup with lime saccharate and phosphoric acid. During this process, air is dissolved into the syrup, and a flocculant is added. Automation of the dosing of lime saccharate, phosphoric acid, flocculant and chemicals was done for the equipment. For syrup clarification, the main clarifying reagents used were lime/lime saccharate and phosphate. In the process of clarification, the treatment of syrup by heat and clarifying agents resulted in the formation of a precipitate which when separated in the clarifier, yielded transparent syrup. In the flotation clarification process, very fine suspended matters were agglomerated and floated to the surface by fine air bubbles.
To enhance the flotation, Dissolved Air Flotation (DAF) was used where bubbles were produced by aerating the syrup under pressure (450 to 500 kPa) and on releasing pressure on the supersaturated solution, the flotation process was considerably enhanced with the use of flocculants leading to mechanical entrapment of air bubbles in floc particles and greatly assisting the separation.
Comparative example 1:
The equipment of the present disclosure was compared with an existing circular in-house design syrup clarifier (a conventional clarifier). A test program was run operating the conventional clarifier and the equipment of the present disclosure, and their performance was compared. Turbidity, colour, temperature and pH were measured for raw/unclarified syrup and clarified syrup.
The Dissolved Air Flotation (DAF) system, syrup reaction tank, treated syrup tank, flocculant and phosphoric acid dosing systems already existing in the plant were used for both the conventional clarifier and the equipment of the present disclosure. Two isolation valves were arranged after the DAF to run any one of the conventional clarifier and equipment. A flocculant dosing connection was given just before the static mixer of the equipment inlet syrup line.
All the operating parameters i.e., syrup flow rate, temperature, chemical dosing, air quantity and pressure of the DAF were maintained at the same levels for the conventional clarifier and the equipment of the present disclosure. Table 2 provides the operating parameters for the equipment of the present disclosure and the conventional clarifier.
Table 2 Operating data of the syrup clarifiers
Configuration Raw syrup Temperature °C Flocculant ppm on
Brix Acid ppm on
Brix DAF
Pressure kg/cm2 Air L/min
Flow rate tons/hour Brix(°Bx) Syrup in Syrup out
Equipment of the present disclosure 39.3±8.7 52.58±3.63 78.4±1.1 77.2±0.8 11.0±4.7 199±56 4.1±0.2 20±0
Conventional clarifier 38.8±6.6 53.00±1.97 79.4±1.3 77.5±2.4 10.0±2.9 205±57 4.2±0.3 20±3
Table 3 provides the performance data of the conventional clarifier and the equipment of the present disclosure by using the above operating parameters. The data is represented in the form of average values ± standard deviation.
Table 3Performance data of the syrup clarifiers
Configuration pH Turbidity at 900 nm
Raw syrup Clear syrup Raw syrup Clear syrup % reduction
Equipment of the present disclosure 6.5±0.1 6.3±0.1 341±92 150±38 54.6±10.6
Conventional clarifier 6.5±0.1 6.3±0.1 336±144 128±33 57.8±14.2
It can be observed from Table 3 that the pH and the turbidity of the clear syrup obtained by using the equipment and the process of the present disclosure were compared to that of the conventional clarifier. A comparative graph for the turbidity at 900 nm is shown in Fig.7. Further, it was observed that there were no significant differences between the operating and performance values of the equipment of the present disclosure and the conventional clarifier, despite the equipment of the present disclosure having a much lower residence time. Furthermore, the floc carryover was negligible even at a higher syrup Brix compared to the conventional clarifier, wherein the floc carryover was significant. Higher brix generally increased the turbidity of the syrup. Higher turbidity reduces the floating efficiency of the flocs and then the heavier flocs move to clear syrup which was not desirable.
The flocculant consumption rate was in the range of 11 ppm to 15 ppm on syrup solids for the conventional clarifier as well as the equipment of the present disclosure. Also, phosphoric acid consumption was about 200 ppm on syrup solids, for both the conventional clarifier as well as the equipment of the present disclosure.12 ppm of flocculant on syrup solids/Brix means for 50 MT of syrup @55 brix%, the flocculant used was 50x0.55x12/1000000 = 0.00033 MT = 0.33 Kg.
Inlet and outlet syrup were analysed for temperature, colour, turbidity, and pH. The quality of the clear syrup was good with turbidity values of around 150 at 900 nm. The colour reduction and the turbidity reductions of the equipment of the present disclosure were similar to the conventional syrup clarifier. The average temperature drop across the system was 1.2°C with the equipment, whereas it was 1.9°C with the conventional syrup clarifier.
The equipment of the present disclosure was in continuous operation for at least 3 months.
Comparison of retention time (processing time)
For all values, the probability p was < 0.001, and there were no significant differences between the operating and performance values of the equipment of the present disclosure and the conventional clarifier, despite the equipment of the present disclosure having a much lower residence time. Fig. 5 shows the variations in turbidity during the trial.
In sugar manufacturing, minimizing processing time is important as sucrose loss is directly proportional to the processing time. Syrup retention time in different clarifiers is tabulated in Table 4.
Table 4 Syrup retention time in different clarifiers
Sr. No. Type of Syrup Clarifier Syrup retention time
1 Conventional syrup clarifier 20 min
2 Equipment of the present disclosure 9 min
It can be observed from Table 4 that the equipment of the present disclosure demonstrated a retention time of 9 minutes and the conventional syrup clarifier demonstrated a retention time of 20 minutes, at a syrup flow rate of 55 m3/hour.
TECHNICAL ADVANCEMENTS
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of, the process for the clarification of the syrup that:
• is simple and efficient, and
• requires less retention/processing time;
and,
the equipment for the clarification of a syrup that:
• 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 syrup, which reduces the inversion loss as well as the heat loss across the equipment, ultimately resulting in a more efficient clarification process; and
• requires lower operating volume, which makes the liquidation process much easier and quicker.
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. A process for clarification of the syrup, said process comprising the following steps:
(i) introducing a pretreated syrup containing a flocculant at a predetermined temperature and a predetermined flow rate to a vessel (100) through an inlet (110) of equipment (1000) operating at a predetermined surface loading rate; wherein said inlet (110) is located at an operative middle section of said vessel (100);
(ii) allowing said pretreated syrup to flow over a plurality of inclined plates (120) in a downward direction within said vessel (100) to separate said pretreated syrup into a clarified syrup and a floating scum;
(iii) scraping said floating scum from an operative top section (130) of said vessel (100) by using a plurality of scrapers (140) moving at a predetermined speed;
(iv) continuously removing the scraped scum from said vessel (100) through a scum outlet (190) while maintaining a predetermined thickness of a scum layer at said operative top section (130); and
(v) discharging said clarified syrup from a clarified syrup outlet (180) connected to an operative bottom section (170) in a predetermined time period.
2. The process as claimed in claim 1, wherein said predetermined temperature is in the range of 75 oC to 85 oC.
3. The process as claimed in claim 1, wherein said predetermined flow rate is in the range of 30 tons per hour to 60 tons per hour.
4. The process as claimed in claim 1, wherein said predetermined speed of said scraper (140) is in the range of 0.5 meter/minute to 1 meter/minute.
5. The process as claimed in claim 1, wherein said predetermined thickness of said scum layer is in the range of 75 mm to 125 mm.
6. The process as claimed in claim 1, wherein said predetermined time period is in the range of 5 minutes to 15 minutes.
7. The process as claimed in claim 1, wherein said predetermined surface loading rate is in the range of 5 meters per hour to 15 meters per hour.
8. An equipment (1000) for the clarification of syrup, said equipment comprising:
• a vessel (100) including
o an inlet (110) at an operative middle section of said vessel (100) configured to receive a pretreated syrup;
o a plurality of inclined plates (120) attached within said vessel (100) at said operative middle section configured to distribute said pretreated syrup over said inclined plates (120) and further configured to separate said pretreated syrup into a clarified syrup and a floating scum; and
o a clarified syrup outlet (180) at an operative bottom section (170) configured to withdraw said clarified syrup;
and
• a plurality of scrapers (140) mounted on an operative top (160) of said vessel (100), said scrapers (140) configured to be driven by a motor (150) and moving along a horizontal axis to scrap said floating scum from an operative top section (130) of said vessel and discharge said scum through a scum outlet (190).
9. The equipment as claimed in claim 8, further comprising a perforated base (125) configured to partition said vessel (100) into said operative middle section and said operative bottom section (170).
10. The equipment as claimed in claim 8, wherein said plurality of inclined plates (120) are arranged in parallel and interspaced at a distance in the range of 25 mm to 75 mm from each other.
11. The equipment as claimed in claim 8, wherein said plurality of inclined plates (120) have a thickness in the range of 2 mm to 10 mm, a height in the range of 1000 mm to 1500 mm, and a width in the range of 1200 mm to 1700 mm.
12. The equipment as claimed in claim 8, wherein said plurality of inclined plates (120) have a count in the range of 30 plates to 80 plates.
13. The equipment as claimed in claim 8, wherein said plurality of inclined plates (120) are provided with a plurality of guide plates (123) to hold said inclined plates at an angle in the range of 25 degrees to 35 degrees with respect to a vertical axis of said vessel (100).
14. The equipment as claimed in claim 8, wherein said clarified syrup outlet (180) is fluidly connected to a box (230), said box (230) containing a telescopic valve, wherein the height of the telescopic valve is adjustable to maintain the required scum thickness in said vessel(100).
15. The equipment as claimed in claim 8, wherein said vessel (100) is configured with a plurality of sensors (200), said plurality of sensors (200) selected from the group consisting of pH sensor, temperature sensor, turbidity sensor, and color sensor.

Dated this 22nd Day of November, 2024

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