Sugarcane clear juice decalcification resin regeneration liquid treatment method and sugarcane clear juice decalcification method

Abstract

The invention provides a treatment method of a sugarcane clear juice decalcification resin regeneration liquid and a sugarcane clear juice decalcification method. The sugarcane clear juice decalcification resin regeneration liquid is treated by a sodium carbonate chemical method to obtain a clear liquid, and the clear liquid is prepared into a regeneration agent of sugarcane clear juice decalcification resin. According to the sugarcane clear juice decalcification method, a continuous multi-column ion exchange resin column is adopted to remove calcium ions in the sugarcane clear juice, a regenerating agent of decalcification resin is a sodium chloride clear liquid obtained by a sodium carbonate chemical method from a regenerating liquid, the problem of environment-friendly treatment of the regenerating liquid is solved, residual sodium chloride in the regenerating liquid can be fully utilized, and the recycling rate of the sodium chloride clear liquid is increased. The input amount of the regenerant is reduced. Sodium chloride clear liquid obtained after excessive reaction of sodium carbonate and calcium chloride in regeneration liquid does not affect regeneration work of the calcium saturated resin column, the adsorption effect is good after resin regeneration, and the resin treatment capacity is kept stable. And a sodium carbonate chemical treatment process is adopted, so that resource recycling of the regenerated liquid can be realized, sewage discharge during actual mass production is reduced, and the industrial production cost is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sugar manufacturing, in particular to a method for treating regeneration liquid of a decalcification resin for cane juice and a method for decalcifying cane juice. BACKGROUND

[0002] In the cane sugar refining process, the reaction of lime milk added in the sulfite clarification process with phosphoric acid and SO2 to form Ca3(PO4)2 and CaSO3 cannot be completely reacted, and the clear juice contains a large amount of calcium ions, resulting in a calcium ion content of 0.37%-0.56% (calcium oxide content in clear juice solid solution), i.e. 400-600 mg / L (calcium ion content in clear juice). In the subsequent evaporation and sugar boiling processes, as water evaporates, part of the calcium ions will crystallize and precipitate, forming scale on the heating pipe wall and reducing heat transfer efficiency; a part of the calcium ions suspended in the syrup will deposit in the white sugar crystal grains during crystallization, increasing the turbidity and ash content of white sugar, which not only increases the production energy consumption but also affects the product quality, which has been a major bottleneck for cost reduction and efficiency improvement in sulfite sugar mills.

[0003] Currently, ion exchange resin method is one of the commonly used methods for decalcification of cane sugar. This method utilizes the selective adsorption of ion exchange resin on calcium ions to remove calcium ions in cane sugar solution, thereby achieving the purpose of decalcification. However, as the decalcification process proceeds, the ion exchange resin will gradually become saturated and lose its decalcification ability, at which point the resin needs to be regenerated to restore its adsorption performance. The existing cane sugar decalcification resin regeneration process has many problems. The main chemical method for resin regeneration—sodium chloride or alkaline sodium chloride solution regeneration method, although simple to operate, consumes a large amount of chemical reagents, and has problems such as difficult treatment of regeneration liquid or incomplete regeneration of resin, which undoubtedly increases the production cost of cane sugar. These regenerants generate a large amount of wastewater during use, and the wastewater contains high concentrations of salts and chemicals, which will cause serious environmental pollution if directly discharged. In addition, the regeneration effect of some regeneration processes is not ideal, and the exchange capacity of the regenerated resin is recovered to a low degree, which cannot meet the demand for efficient decalcification, affecting the continuity and stability of cane sugar production.

[0004] Among the domestic published patents related to decalcification technology, Chinese patent CN202111235828.1 discloses a beet sugar decalcification system, and the regenerant for the softening of the dilute juice is NaOH; Chinese patent CN202410070515.2 discloses a sugar cane decalcification method and system, and the regenerant for the decolorizing resin is a mixed salt-alkali solution with a NaCl content of 9% and a NaOH content of 0.25%, and the regenerant for the decalcification ion exchange resin is a liquid obtained by neutralizing the regeneration solution of the decolorizing ion exchange resin with acid, which is mainly applied to the raw sugar refining process; Chinese patent CN00130871.8 discloses a regeneration solution for ion exchange resin used in sugar liquid decolorization and a regeneration method thereof, which mainly uses CO2 saturation or phosphoric acid to precipitate calcium ions to form calcium carbonate or calcium phosphate, and the filtered solution can be reused, which is mainly applied to sugar cane decolorization; Chinese patent 201010571078.0 discloses a regeneration method for sugar-making decolorization and decalcification resin and a recycling method for the regeneration solution, the regenerant for the decolorization resin is an alkaline salt water, i.e. a mixed salt-alkali solution containing 120 g / L NaCl and 5 g / L NaOH, the regenerant for the decalcification resin is the regeneration solution containing pigments after decolorization, and the regeneration solution for the decalcification resin is concentrated and dried to obtain a salt-containing calcium-rich pigment product, which is still in the laboratory stage. Chinese patent CN202011016180.4 discloses a resin regeneration solution resource utilization system and process, which uses nanofiltration and reverse osmosis technology to resourcefully treat the waste liquid.

[0005] It can be seen that the current domestic patent technologies using ion exchange resin for desalination and decolorization of sugar juice and syrup are mainly applied to the raw sugar refining process or the beet sugar production process, and are based on the low concentration of calcium ions in the raw materials.

[0006] However, the composition of the raw material in the sugar cane clarification process is relatively complex, the composition of the sugar cane juice is different from that of the beet juice, and the content of residual calcium ions in the raw material during the production process is much higher than that in the raw sugar or beet juice, which increases the difficulty of decalcification technology for sugar cane juice.

[0007] After decolorization and decalcification using ion exchange resin, a large amount of regeneration solution is generated during the resin regeneration process, which cannot be treated. There are few patents reported on the application of ion exchange resin for decolorization and decalcification in the sugar cane production process, the treatment and recycling of resin regeneration solution, and the main problem is the environmental pollution caused by the regeneration solution. SUMMARY

[0008] The present application mainly solves the environmental pollution problem caused by the regeneration solution after decalcification of sugar cane juice, provides a new regeneration solution treatment process, basically does not produce waste liquid, and the exchange capacity of the regenerated resin is high, which can meet the demand for efficient decalcification.

[0009] To solve the above technical problems, the present application provides a technical solution as follows: A sugarcane juice decalcification resin regeneration liquid treatment method, the clear liquid obtained by treating the sugarcane juice decalcification resin regeneration liquid by a sodium carbonate chemical method is configured as a regeneration agent for the sugarcane juice decalcification resin. The sugarcane juice decalcification resin regeneration liquid refers to a regeneration waste liquid formed by adding the regeneration agent after the decalcification resin is saturated.

[0010] The sodium carbonate chemical treatment method comprises the following steps: S1. Adding excess sodium carbonate to the sugarcane juice decalcification resin regeneration liquid to fully react to obtain a mixed solution of sodium chloride and calcium carbonate; S2. Filtering the mixed solution of sodium chloride and calcium carbonate to obtain calcium carbonate precipitate and clear liquid.

[0011] The method for configuring the regeneration agent for the sugarcane juice decalcification resin is as follows: part of the clear liquid is used as a solid sodium chloride solvent to prepare a saturated sodium chloride solution; and the remaining clear liquid is mixed with the saturated sodium chloride solution to prepare an 8%-10% sodium chloride regeneration agent.

[0012] When the sodium carbonate chemical treatment is performed, the amount of added sodium carbonate is N times the amount of substance of calcium ions in the regeneration liquid, N = 1.5-3.5, the reaction time is 10-40 minutes, and the reaction temperature is 30℃-60℃.

[0013] The pH value of the regeneration agent solution is adjusted to 6.5-9.5.

[0014] The present application also provides a sugarcane juice decalcification method, which uses a continuous multi-column ion exchange resin column to remove calcium ions in the sugarcane juice, and the sugarcane juice decalcification resin regeneration liquid is treated by the aforementioned treatment method.

[0015] The method for removing calcium ions in the clear juice by the continuous multi-column ion exchange resin column comprises the following procedures: Production procedure: the sugarcane juice is subjected to ion exchange through the resin layers of multiple ion exchange resin columns arranged in parallel to obtain a decalcified clear juice solution; Backwashing procedure: the impurities in the ion exchange resin column that are no longer effective in the production procedure are washed out with sugarcane juice; here, the sugarcane juice refers to non-decalcified sugarcane juice; Water topping procedure: the residual sugarcane juice in the ion exchange resin column after the backwashing is completed is washed out with steam condensed water with a temperature of 70-98℃; Regeneration procedure: the multiple ion exchange resin columns arranged in series after the water topping procedure is completed are regenerated with a regeneration agent; Elution procedure: the multiple ion exchange resin columns arranged in series after the regeneration procedure is completed are cleaned with steam condensed water with a temperature of 30-65℃.

[0016] The effluent solution of the elution process is added to the regenerant pipeline to mix with the regenerant and enter the ion exchange resin column in the regeneration process.

[0017] The amount of regenerant for the ion exchange column in the regeneration process per cycle is controlled to be 1.0-2.0 BV.

[0018] The amount of low-temperature steam condensate in the elution process per cycle is controlled to be 0.5-1.0 BV.

[0019] The single-column volume of the ion exchange resin column is 1-15 m 3 .

[0020] The resin in the ion exchange resin column is Na-type cation exchange resin.

[0021] The feeding mode of the production process is top feeding and bottom discharging; the feeding mode of the backwashing process is bottom feeding and top discharging; the feeding mode of the water top sugar process is top water feeding and bottom discharging; the feeding mode of the regeneration process is top regenerant feeding and bottom discharging; and the feeding mode of the elution process is top water feeding and bottom discharging.

[0022] The regeneration process adopts 2-5 ion exchange resin columns arranged in series. The top feeding port of the first ion exchange resin column in the regeneration process is fed with the regenerant, the bottom discharging port is connected to the top feeding port of the second ion exchange column, the bottom discharging port of the second ion exchange resin column is connected to the top feeding port of the third ion exchange resin column, and so on, and the bottom discharging port of the last ion exchange resin column is discharged, which can reduce the number of ion exchange resin columns and the amount of regenerant.

[0023] The elution process adopts 2-5 ion exchange resin columns arranged in series. The top feeding port of the first ion exchange resin column in the elution process is fed with water, the bottom discharging port is connected to the top feeding port of the second ion exchange resin column, the bottom discharging port of the second ion exchange resin column is connected to the top feeding port of the third ion exchange resin column, and so on, and the bottom discharging port of the last ion exchange resin column is discharged, which saves the amount of elution water.

[0024] The above scheme of the application at least has the following beneficial effects: The regenerant of the decalcification resin is selected from the sodium chloride clear solution obtained by the sodium carbonate chemical method, which solves the environmental protection treatment problem of the regeneration liquid, and can fully utilize the residual sodium chloride in the regeneration liquid to reduce the input amount of the regenerant.

[0025] The sodium carbonate chemical treatment process can realize the recycling of the regeneration liquid, reduce the discharge of sewage in actual mass production, and reduce the industrial production cost. The solid sodium chloride is dissolved by using the sodium chloride dilute solution obtained by the regeneration liquid reaction filtration, which avoids the use of external water and reduces the total amount of the regeneration liquid, thereby realizing the recycling of the regeneration liquid.

[0026] Through repeated research, it is found that the regenerated agent reused after a specific process treatment (including excess reaction and pH adjustment) does not affect the regeneration efficiency of the resin. The adsorption capacity of the resin after regeneration is recovered well, and the treatment capacity is stable, which proves the long-term feasibility of the recycling process and breaks the technical prejudice that the reuse of the regenerated liquid may cause performance degradation.

[0027] The sugarcane juice decalcification method has good decalcification effect, and the calcium ion content is reduced from 400-600ppm before decalcification to below 0-60ppm after decalcification, the treatment capacity is 45-50BV, and the decalcification rate is as high as 90% or above.

[0028] The sugarcane juice decalcification method of the application obtains the decalcified juice solution, i.e. the softened juice solution, which enters the subsequent evaporator and other processes, greatly reducing the scaling phenomenon of the evaporation tank, crystallization tank and other equipment, eliminating the need for daily tank shutdown and descaling of the evaporation tank, crystallization tank and other equipment, saving labor cost for descaling, and realizing energy-saving, green and low-carbon production. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is a decalcification resin regeneration liquid treatment process schematic diagram of the application.

[0030] Figure 2 is a sugarcane juice decalcification method flowchart of the application.

[0031] Figure 3 is a sugarcane juice decalcification method flowchart of the application. DETAILED DESCRIPTION

[0032] Exemplary embodiments of the present disclosure will be described in greater detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that the present disclosure can be more thoroughly understood and the scope of the present disclosure can be accurately conveyed to those skilled in the art.

[0033] A sugarcane juice decalcification resin regeneration liquid treatment method, the sugarcane juice decalcification resin regeneration liquid is configured as a regeneration agent of the sugarcane juice decalcification resin after being treated by a sodium carbonate chemical method to obtain a clear liquid.

[0034] The specific treatment method is as shown in Figure 1 includes the following steps: S1. The sugarcane juice decalcification resin regeneration liquid is stored in a regeneration liquid tank, and then enters a chemical reaction process. Sodium carbonate in a sodium carbonate storage tank is added to the chemical reaction process through a spiral conveying groove. After the sugarcane juice decalcification resin regeneration liquid and excess sodium carbonate are fully reacted, a sodium chloride and calcium carbonate mixed liquid is obtained. S2. The mixture of sodium chloride and calcium carbonate is filtered to obtain calcium carbonate precipitate and clear filtrate-sodium chloride filtrate, part of the sodium chloride filtrate is sent to a salt dissolving tank, solid sodium chloride is added to the salt dissolving tank to prepare a saturated sodium chloride solution, and the other part of the sodium chloride filtrate is sent to a filtrate storage tank and is used subsequently with the saturated sodium chloride solution to prepare a regenerant for resin regeneration, the regenerant being 8%-10% sodium chloride, and the pH value being 6.5-9.5.

[0035] A method for removing calcium ions from sugarcane juice by using a continuous multi-column ion exchange resin column, and a clear filtrate obtained by treating a regeneration solution of the sugarcane juice decalcification resin by a sodium carbonate chemical method is used to prepare a regeneration agent for the sugarcane juice decalcification resin.

[0036] A specific method for removing calcium ions from sugarcane juice is shown in Figure 2 and includes the following steps: Production process: the clear juice in the feed tank is filtered again and then enters the production area, the production area is composed of multiple ion exchange resin columns arranged in parallel, the clear juice is subjected to ion exchange through the resin layer to obtain decalcified clear juice solution; the volume of a single column of the ion exchange resin column is 1-15m 3 ; the resin in the ion exchange resin column is Na-type cation exchange resin. The feeding mode of the production process is top feeding and bottom discharging.

[0037] Backwashing process: the ion exchange resin column saturated with adsorption in the production process is switched to the backwashing area, the backwashing area is composed of one ion exchange resin column, and the impurities in the ion exchange resin column are washed out by using the feed clear juice-uncalcified clear juice. The feeding mode of the backwashing process is bottom feeding and top discharging. The backwashing liquid discharged from the backwashing process enters the feed tank. The applicant finds that the uncalcified sugarcane juice has less impurities compared with the failed ion exchange resin column, and the fine impurities accumulated on the upper part of the resin layer in the column can be washed out through backwashing, and the resin is loosened. Since the backwashing liquid cannot enter the post-decalcification process, if water or decalcified clear juice is used, it will cause a large amount of resource waste. Therefore, the use of uncalcified sugarcane juice to backwash the failed resin column in production can achieve the backwashing effect and reduce the production cost.

[0038] Water topping sugar process: the ion exchange resin column after backwashing is switched to the water topping sugar area, the water topping sugar area is composed of 2-5 ion exchange resin columns arranged in series, and the residual clear juice in the ion exchange resin column is washed out by using high-temperature steam condensate water at 70-98℃. The feeding mode of the water topping sugar process is top water feeding and bottom discharging.

[0039] Steam condensate water is steam condensate water in the evaporation and concentration process of a sugar factory, and steam condensate water at different temperatures can be obtained according to different efficiency numbers. The conductivity of such water is very low, and the pH value is weakly alkaline, which is more suitable for replacing desalinated water. The use of high-temperature steam condensate water can reduce the production steam consumption.

[0040] Regeneration process: the ion exchange resin column completed water topping sugar is switched to regeneration area, the regeneration area is composed of 2-5 ion exchange resin columns in series, and the ion exchange resin column after completing the water topping sugar process is regenerated with a regeneration agent. The preparation method of the regeneration agent is: first, obtain sodium chloride clear liquid through the process shown in Figure 1 , then add hydrochloric acid to it, adjust the pH value to 6.5-9.5, and finally obtain the regeneration agent.

[0041] The regeneration agent is fed into the first ion exchange resin column of the regeneration process through the inlet, and the outlet is connected to the upper inlet of the second ion exchange column. The lower outlet of the second ion exchange resin column is connected to the upper inlet of the third ion exchange resin column, and so on. The regeneration liquid discharged from the lower outlet of the last ion exchange resin column is used for the aforementioned treatment.

[0042] Elution process: the ion exchange resin column after regeneration is switched to the elution area, the elution area is composed of 2-5 ion exchange resin columns in series, and the ion exchange resin column after completing the regeneration process is cleaned with 30-65°C low-temperature steam condensate water. The water is fed into the first ion exchange resin column of the elution process through the inlet, and the outlet is connected to the upper inlet of the second ion exchange resin column. The lower outlet of the second ion exchange resin column is connected to the upper inlet of the third ion exchange resin column, and so on. The discharge solution discharged from the lower outlet of the last ion exchange resin column is added to the regeneration agent pipeline and mixed with the regeneration agent to enter the ion exchange resin column in the regeneration process.

[0043] The ion exchange resin column after elution is switched back to the production area. Example 1

[0044] The clear juice decalcification method and regeneration liquid treatment process are explained in combination with the clear juice decalcification method and regeneration liquid treatment process flow diagram as follows. As shown in Figure 3 : The clear juice decalcification process includes multiple Na-type cation exchange resin columns, and the volume of a single column is 1-15 m 3 . The multiple ion exchange resin columns are divided into production area 101, backwashing area 102, water topping sugar area 103, regeneration area 104 and elution area 105, which perform production process, backwashing process, water topping sugar process, regeneration process and elution process respectively. Production area 101: including multiple (≥2) ion exchange resin columns arranged in parallel, the clear juice raw material is ion exchanged by passing through the resin layer of multiple ion exchange resin columns arranged in parallel, and the decalcified clear juice solution (softened clear juice) is obtained after the clear juice raw material is decalcified. The upper opening of the ion exchange resin column is communicated with the clear juice feeding pipe 6, the automatic filter 5, the clear juice pump one 2 and the clear juice pump two 3. Two pumps are used in turn. The clear juice pump one 2 and the clear juice pump two 3 are communicated with the automatic filter 5 through the clear juice pipeline 4. The clear juice pump transports the material in the feeding tank 1 to the ion exchange resin column. The lower opening of the ion exchange resin column is connected and communicated with the clear juice discharge pipe 7 and the softened clear juice tank 8. The clear juice bypass pipeline 11 is arranged between the softened clear juice tank 8 and the clear juice pipeline from the sedimentation tank, which facilitates the switching of materials when the clear juice decalcification process is stopped. The material in the softened clear juice tank 8 is transported by the softened clear juice pump 9 to the evaporation section through the pipeline 10. The production area 101 of the embodiment is provided with 6 ion exchange resin columns (the N5-N10 ion exchange resin columns), but 6 is not a fixed number. The number of ion exchange resin columns can be increased or decreased according to the production capacity in actual industrial production.

[0045] Backwashing area 102: including the invalid ion exchange resin column switched from the production area. In the embodiment, the backwashing area 102 is provided with 1 ion exchange resin column (the N4 ion exchange resin column). The lower opening of the ion exchange resin column is connected and communicated with the clear juice pipeline after the automatic filter 5, the backwashing feeding pump 21 and the backwashing feeding pipeline 22. The lower opening of the ion exchange resin is also connected and communicated with the compressed air backwashing pipeline 12 through the backwashing feeding pipeline 22. Valves are arranged on the pipelines. If necessary, compressed air can be used to loosen the resin in the ion exchange resin column, reduce the backwashing material and improve the backwashing efficiency. The upper opening of the ion exchange resin column is connected and communicated with the backwashing discharge pipeline 23. The backwashing discharge returns to the front end of the main process for re-filtering. Automatic on-off valves are arranged on the corresponding pipelines to sequentially perform the blowing and backwashing work.

[0046] The backwashing process is to wash out the impurities in the ion exchange column with the clear juice before decalcification. The backwashing liquid is re-filtered in the main process and then subjected to decalcification treatment. In the traditional process, pure water is used for backwashing. In this case, the clear juice before decalcification is used for backwashing. The amount of backwashing liquid does not affect the hammer degree of the material. The amount mainly depends on the cleanliness of the incoming clear juice. The backwashing liquid is filtered before returning to the front end of the main process and then continues to be used in the production system. This method can reduce the use of water outside the process and avoid increasing energy consumption.

[0047] Water topped sugar area 103: including 2-5 ion exchange resin columns switched from the backwashing area. In the embodiment, the water topped sugar area 103 is provided with 3 ion exchange resin columns in series for topping sugar (the N1-N3 ion exchange resin columns). However, 3 is not a fixed number. The number of ion exchange resin columns can be increased or decreased according to the production capacity in actual industrial production.

[0048] The water-topped sugar process uses 70-98℃ high-temperature condensed water to wash the clarified juice in the ion exchange column to 0 saturation. The upper end of the first ion exchange resin column is connected to the high-temperature condensed water pipe 31. Water enters from the upper end of the ion exchange resin column and material exits from the lower end in the water-topped sugar process. This water-inlet washing method can clean the material more quickly. Moreover, by using multiple columns in series to top the sugar, the water consumption is 0.5-1.0 BV, which can wash the sugar to 0 saturation. The water consumption is greatly reduced compared to the traditional single-column water consumption of 1-1.5 BV. The lower end of the last ion exchange resin column is connected to the feed tank 1 through the sugar water recovery pipe 32.

[0049] Regeneration Zone 104: This zone includes 2-5 ion exchange resin columns switched from the water-sugar zone. The resin in the ion exchange resin columns is regenerated using sodium chloride solution obtained after the regeneration solution has undergone a sodium carbonate chemical process. In this embodiment, Regeneration Zone 104 is equipped with 3 ion exchange columns connected in series (N14-N16 ion exchange resin columns). The upper end of the first ion exchange resin column is connected to the regenerant feed pipe 41. The lower end of the first ion exchange resin column is connected in series to the upper end of the second ion exchange resin column via a pipe. The lower end of the second ion exchange resin column is connected in series to the upper end of the third ion exchange resin column via a pipe. The lower end of the third ion exchange resin column is the discharge point. The lower end of the third ion exchange resin column is connected to the regeneration solution tank 46 via pipe 45. At this time, the material in the regeneration solution tank 46 is a solution rich in calcium chloride. This solution is transported to the regeneration solution reaction process via the regeneration solution to reaction tank pipe 47. The amount of regenerant used in the ion exchange columns is 1.0-2.0 BV. However, the number of 3 columns is not fixed; in actual industrial production, the number of ion exchange resin columns can be increased or decreased depending on the production volume.

[0050] When the last ion exchange column in the regeneration zone is switched from the water-top sugar zone, it contains a small amount of water. When the regenerant enters the column, the initial wash solution discharged has a sugar content of 0 and a very low chloride ion content. Depending on the amount of regenerant to be recycled, about 0.2-0.8 BV of the initial wash solution is connected to the recovery water tank 43 through the regenerant discharge pipe 42 from the bottom of the last ion exchange column. At this time, the chloride ion content of the wash solution in the recovery water tank 43 is controlled at 0-1000 mg / L, the calcium salt content is 0-100 ppm, and the COD content is 0-4000 mg / L. The amount of water recovered is about 0.2-0.8 BV, which can be transported to the external cooling tower for recycling through the recovery water pump 44.

[0051] Rinsing zone 105: Includes 2-5 ion exchange resin columns switched from the regeneration zone. The ion exchange columns are rinsed with 30-65℃ low-temperature condensate water. When the rinsing water volume is 0.5-1.0 BV, a rinsing solution with 0% saturation, 0% calcium salt content, and conductivity <1000 μS / cm can be obtained. In this embodiment, rinsing zone 105 is equipped with 3 ion exchange resin columns connected in series (N11-N13 ion exchange resin columns). The upper end of the first ion exchange resin column is connected to the low-temperature condensate water pipe 82 and the low-temperature condensate water pump 81, and its lower end is connected in series through a pipe to the upper end of the second ion exchange resin column. The lower end of the second ion exchange resin column is connected in series through a pipe to the upper end of the third ion exchange resin column, and the lower end of the third ion exchange resin column is the discharge outlet. The lower end of the third ion exchange resin column is connected in series via a pipe to the regenerant feed pipe 41, which is connected to the upper end of the first ion exchange resin column in the regeneration zone 104. Since the third column in the rinsing zone is switched from the regeneration zone, there is still some unused regenerant inside. Therefore, the outlet pipe of the rinsing zone is connected to the inlet pipe of the regeneration zone, and the rinsing solution is used in the regeneration zone. Thus, the rinsing zones are connected in series to save rinsing water, and the rinsing zone and regeneration zone are connected in series for regeneration, allowing for full utilization of the rinsing solution and saving regenerant usage. A mixer is installed on the regenerant feed pipe 41. The number of resin columns in the rinsing zone (3) is not fixed; in actual industrial production, the number of ion exchange resin columns can be increased or decreased according to the production volume.

[0052] The process of clearing juice and decalcifying is continuous. When the ion exchange resin column in the production area becomes saturated, it is switched out and enters the backwashing area. After being cleaned, it is switched to the water-sugar-topping area, regeneration area, and rinsing area. Through sequential switching, the number of ion exchange resin columns in each working area is kept constant, so that clearing juice and decalcifying can be carried out continuously.

[0053] The chemical treatment process for regenerated liquid using sodium carbonate includes a chemical reaction zone 106, a filtration zone 107, and a regenerator preparation zone 108, which respectively perform the sodium carbonate chemical reaction process, the filtration process, and the regenerator preparation process, wherein: Chemical reaction zone 106: This includes a pipeline 47 connecting the regenerated liquid from regenerated liquid tank 46 to reaction tanks 54 and 55, both equipped with stirrers. One tank is used as a backup. The regenerated liquid is fed from the top and discharged from the bottom. Sodium carbonate is conveyed to sodium carbonate storage tank 52 via elevator 51. Sodium carbonate is discharged from the bottom of sodium carbonate storage tank 52, and the discharge pipeline is connected to a spiral conveyor trough 53. The outlet pipeline of the spiral conveyor trough 53 is connected to the top of both reaction tanks 54 and 55. Sodium carbonate storage tank 52 is equipped with a weighing sensor, which can accurately control the amount of sodium carbonate added. Sodium carbonate is added from the spiral conveyor trough 53 to either reaction tank 54 or reaction tank 55. The purpose of the stirrers in the reaction tanks is to ensure that the sodium carbonate reacts quickly and fully with the calcium ions in the regenerated liquid. The reaction time is generally controlled between 10-40 minutes, resulting in a turbid substance with calcium carbonate precipitate. The lower inlet of reaction tank 54 (first reaction tank) or reaction tank 55 (second reaction tank) is connected to mud pump 56 (first reaction tank) or mud pump 57 (second reaction tank) and reaction liquid conveying pipeline 58, respectively, to transport the material to the filtration process. One mud pump is in operation and one is on standby. The amount of sodium carbonate added is N times the amount of calcium ions in the regenerated liquid, where N = 1.5-3.5. The reaction temperature is controlled at 30-60℃, and the stirring reaction time is 10-40 minutes. The calcium ion reaction rate can reach over 95%.

[0054] In this embodiment, the sodium carbonate elevator is not essential equipment and can be configured according to the production site. The upper openings of reaction tank 1 (54) and reaction tank 2 (55) equipped with agitators are respectively provided with circulation pipes connected to the outlet of the mud pump to prevent blockage of the inlet pipes when the reaction tanks are not in use. The upper opening of reaction tank 2 (55) is provided with a reaction liquid circulation pipe 59 connected to the outlet of the plate and frame filter press to receive the reaction liquid for return use in case of filtration abnormalities.

[0055] Filtration zone 107 includes the reaction liquid conveying pipeline 58 and plate and frame filter presses 61 and 62. One plate and frame filter press is in operation while the other is on standby. The outlet filtrate pipeline 63 of the plate and frame filter press is connected to the upper opening of the filtrate tank 64. The lower opening of the filtrate tank is connected to the filtrate pump 65 and to the filtrate filters 66 and 67, respectively, and to the filtrate desalination tank pipeline 68. The two filters are used in parallel. The feed inlets of both plate and frame filter presses 61 and 62 are connected to compressed air pipelines and low-temperature condensate pipelines 82. The outlets of both plate and frame filter presses are equipped with drain pipes for emergency drainage in case of production abnormalities.

[0056] The regenerant preparation area 108 includes a filtrate to regeneration pipeline 69 and a salt dissolving tank 71. Solid sodium chloride is dissolved in the salt dissolving tank 71 using the filtrate from the filtrate to salt dissolving tank pipeline 68 as a solvent. The resulting saturated solution is connected to a brine pump 72 and a brine pipeline 73 via the lower outlet pipeline of the salt dissolving tank. The saturated brine is then connected to the filtrate to regeneration pipeline 69 via the brine pipeline 73. After being adjusted by an online metering instrument to prepare an 8%-10% sodium chloride regenerant, it is finally connected to the regenerant inlet pipeline 41. The regenerant pH control system is connected to the hydrochloric acid pump 75, a hydrochloric acid pipeline 76, and the regenerant inlet pipeline 41 via the lower outlet of the hydrochloric acid storage tank 74. The hydrochloric acid and regenerant are mixed via a pipeline mixer 77, and the resin in the regeneration area is regenerated after being controlled by an online pH meter. The pH value of the regenerant solution is 6.5-9.5. The salt dissolving tank is equipped with a compressed air pipeline for pneumatic stirring of the brine.

[0057] The chemical reaction treatment of the regenerated liquid is carried out in continuous production. The regenerated liquid is circulated sequentially from the chemical reaction zone, the filtration zone, and the regenerator preparation zone to ensure the normal operation of the juice clearing and decalcification process. Example 2

[0058] Chemical treatment process test of regenerated liquid sodium carbonate Sodium chloride is the most traditional regenerator for Na-type cation exchange resins. It works by providing sodium ions (Na+). + To replace calcium (Ca) in the resin 2+ ) and magnesium (Mg 2+ The sodium carbonate ion is reacted with calcium ions in the solution to restore the exchange capacity of the resin; the sodium carbonate chemical method for removing calcium salts from the solution is a classic chemical precipitation method, in which sodium carbonate reacts with calcium ions in the solution to form calcium carbonate precipitate, which is then removed.

[0059] (1) Using the decalcification process of Example 1, the regenerant initially used on the exhausted resin was a 10% sodium chloride solution. The regenerant obtained from resin regeneration contained a large amount of calcium chloride and some unused sodium chloride. After adding excess sodium carbonate to react with it, the reaction temperature was controlled at 30~40℃. After filtration, a sodium chloride solution with low calcium ion content was obtained as the regenerant. The comparative data are as follows:

[0060] N refers to the multiple of the amount of sodium carbonate added to the amount of calcium ions in the regenerated solution. N = 1.2 means that the amount of sodium carbonate added is 1.2 times the amount of calcium ions in the regenerated solution.

[0061] The results show that the more sodium carbonate is added to the regenerated solution, the lower the calcium ion content in the filtrate after the reaction. When N=1.5-4.0, the calcium ion reaction rate in the regenerated solution can reach over 95%. Regardless of the calcium ion content in the regenerated solution, after adding an appropriate amount of sodium carbonate, the calcium ion concentration in the filtrate can be ≤200mg / L, and the calcium ion reaction rate can reach over 95%. Considering cost savings, N=1.5-3.5 can be selected.

[0062] (2) Using the decalcification process of the juice in Example 1, the regenerated liquid obtained by regenerating the calcium-saturated resin column was obtained. When N=3.5, the reaction temperature was controlled at 30~40℃. The calcium ion content of the filtrate was obtained at different reaction times as follows:

[0063] The results show that the reaction time between sodium carbonate and calcium ions is within 10-40 minutes. Regardless of the concentration of calcium ions in the regenerated solution, the reaction rate can reach over 99% when sufficient sodium carbonate is added.

[0064] (3) Using the decalcification process of Example 1, the regenerated liquid obtained by regenerating the calcium-saturated resin column, when N=3.5 and the stirring reaction time is within 10-40 minutes, under different temperature conditions, the calcium ion content index of the filtrate is as follows:

[0065] The results show that at N=3.5, the higher the temperature, the higher the calcium ion concentration in the filtrate after the reaction. When the temperature is controlled between 30℃ and 60℃, the calcium ion reaction rate can reach over 99%. In large-scale production, the appropriate value can be determined based on the material temperature.

[0066] The above experiments show that: N=1.5-3.5, reaction time 10-40 minutes, reaction temperature controlled at 30℃-60℃, calcium ion reaction rate of regenerated liquid reaches more than 95%, and calcium ion content of the obtained filtrate can be controlled below 200mg / L.

[0067] Considering the excess CO3 remaining when treating the regenerated liquid using the sodium carbonate method 2- Residue in the regenerator will react with Ca on the resin. 2+ CaCO3 precipitate forms and remains in the resin column, unable to be discharged, thus affecting subsequent production. Based on the CO3 content in the sodium chloride regenerator... 2- The residual amount was eliminated by adding HCl, and the pH control parameters of the regenerated solution were as follows:

[0068] The results show that residual carbonate ions in the sodium chloride regenerator solution prepared by the sodium carbonate method can be removed by adding acid. When the pH of the regenerator is controlled below 9.5, the carbonate removal rate can reach over 90%, and when the pH is controlled below 8.0, the residual carbonate ions in the sodium chloride regenerator solution are essentially reduced to 0 mg / L. The presence of trace amounts of carbonate ions in the regenerator has little impact on subsequent resin regeneration and recycling. Therefore, the pH of the regenerator solution can be selected between 6.5 and 9.5. Example 3

[0069] The application of the regenerated solution in the recycling and regeneration of resin after treatment with sodium carbonate.

[0070] The regenerated liquid obtained in Example 2 was treated with sodium carbonate (N=3.5), with a reaction time of 10-40 minutes and a reaction temperature of 30-60°C. The resulting sodium chloride solution, after filtration, was then prepared into a sodium chloride solution with a viscosity of approximately 10% using saturated sodium chloride solution as a regenerating agent. The pH of the regenerated liquid was controlled at 6.5-9.5. This process was used to regenerate and recycle the exhausted resin. After 20 cycles, the average decalcification rate of the resin reached over 90%, and the average material throughput in the production area reached 47.5 BV. The statistical data are as follows:

[0071] The calcium ion concentration in the feed slurry is 440-560 mg / L, the temperature is 80-90℃, the feed flow rate is 10 BV / h, and the regeneration flow rate is 1 BV / h. Example 4

[0072] The difference between this embodiment and embodiment 3 is that a comparative experiment was conducted on calcium-saturated resin columns using a mixture of salt-alkali solution and sodium hydroxide decalcification solution as regenerators.

[0073] (1) The decalcification process of the clarifier in Example 1 was adopted. All regenerators of the exhausted resin were regenerated using a saline-alkali solution. The saline-alkali solution was prepared by mixing 1% sodium hydroxide and 9% sodium chloride to form a 10% saline-alkali solution, which was used as the regenerator to regenerate the calcium-saturated resin column. The pH value of the regenerator was 9-11, and the regenerated solution was not reused. The feed flow rate was 10 BV / h, and the regeneration flow rate was 1 BV / h. The material throughput in the production area and the decalcification rate after resin regeneration are as follows:

[0074] The results showed that when using salt-alkali solution for regeneration, the resin decalcification rate decreased significantly in the fourth cycle of production, and the material throughput decreased from 53 BV to 5 BV. This indicates that the resin recovery ability is very poor when using salt-alkali solution for regeneration, and it cannot maintain normal production.

[0075] (2) The decalcification process of the juice in Example 1 was adopted. The regenerator was a mixture of sodium hydroxide and decalcified juice, i.e., 32% NaOH + decalcified juice, prepared into a regenerator with a concentration of 4%-7% to regenerate the resin. The regenerated liquid was returned to the front end of the production process to be mixed with the sugarcane juice and then clarified. The pH value of the regenerator was 14. The feed flow rate was 10 BV / h, and the regeneration flow rate was 1 BV / h. The material processing volume in the production area and the decalcification rate after resin regeneration are as follows:

[0076] The results showed that after 3-4 cycles of operation, precipitates appeared in the resin column during the regeneration process, indicating incomplete resin regeneration. This resulted in a decrease in resin throughput from 45 BV to 24 BV after the third cycle, making it impossible to maintain normal regeneration cycle operation, and the output calcium salt content was also too high. This indicates that when using a mixture of sodium hydroxide and decalcified slurry as a regenerant, the resin's recovery ability is poor, making it unable to maintain normal production.

[0077] Comparative experiments in Examples 2, 3, and 4 revealed that when using a saline-alkali solution as a regenerator, the regenerated solution could not be recycled, and the resin's adsorption capacity decreased after regeneration, resulting in poor decalcification. When using a mixture of sodium hydroxide and decalcified juice as a regenerator, precipitates were generated during the regeneration process, leading to incomplete regeneration, decreased resin adsorption capacity, and poor decalcification. This essentially confirms that the saline-alkali solution and NaOH solution regeneration processes are unsuitable for sugarcane juice with high calcium salt content (400-600 mg / L). However, using NaCl solution as a regenerator effectively solves the problem of incomplete resin regeneration under high calcium salt content in sugarcane juice. Furthermore, the regenerator obtained by treating the regenerated solution using the sodium carbonate method can be recycled, effectively addressing the environmental pollution problem of the regenerated solution.

[0078] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for treating sugarcane juice decalcification resin regeneration solution, characterized in that, The clarified liquid obtained by treating sugarcane juice decalcification resin regeneration solution with sodium carbonate chemical method is used as a regenerator for sugarcane juice decalcification resin. The chemical treatment method for sodium carbonate includes the following steps: S1. Sugarcane juice decalcification resin regeneration solution is reacted with excess sodium carbonate to obtain a mixture of sodium chloride and calcium carbonate; S2. Filtering a mixture of sodium chloride and calcium carbonate yields calcium carbonate precipitate and a clear liquid.

2. The method for treating sugarcane juice decalcification resin regeneration solution according to claim 1, characterized in that, The method for preparing the regenerator for sugarcane juice decalcification resin is as follows: part of the clear liquid is used as a solid sodium chloride solvent to prepare a saturated sodium chloride solution; the remaining clear liquid is mixed with the saturated sodium chloride solution to prepare an 8%-10% sodium chloride regenerator.

3. The method for treating sugarcane juice decalcification resin regeneration solution according to claim 1, characterized in that, When using the sodium carbonate chemical treatment method, the amount of sodium carbonate added is N times the amount of calcium ions in the regeneration solution, where N = 1.5-3.

5. The reaction time is 10-40 minutes, and the reaction temperature is 30℃-60℃.

4. The method for treating sugarcane juice decalcification resin regeneration solution according to claim 2, characterized in that, The pH of the regenerator solution is adjusted to 6.5-9.

5.

5. A method for decalcifying sugarcane juice, characterized in that, A continuous multi-column ion exchange resin column is used to remove calcium ions from sugarcane juice, and the sugarcane juice decalcification resin regeneration solution is treated by the method described in any one of claims 1-4.

6. The method for decalcifying sugarcane juice according to claim 5, characterized in that, The method for removing calcium ions from clarified juice using a continuous multi-column ion exchange resin column includes the following steps: Production process: Sugarcane juice is decalcified by passing through the resin layer of multiple parallel ion exchange resin columns to obtain a decalcified juice solution. Backwashing process: Sugarcane juice is used to wash out impurities in the ion exchange resin column that have failed in the production process; Sugar removal process: Use condensed water at a temperature of 70-98℃ to wash out the residual sugarcane juice in the ion exchange resin column after backwashing. Regeneration process: The multiple ion exchange resin columns connected in series after the sugar-topping process are regenerated using a regenerating agent; Rinsing process: The multiple ion exchange resin columns connected in series after the regeneration process are cleaned with condensed water at a temperature of 30-65℃.

7. The method for decalcifying sugarcane juice according to claim 6, characterized in that, The effluent solution from the rinsing process is added to the regenerant pipeline and mixed with the regenerant before entering the ion exchange resin column in the regeneration process.

8. The method for decalcifying sugarcane juice according to claim 6, characterized in that, The amount of regenerant used in each cycle of the regeneration process is controlled at 1.0-2.0 BV.

9. The method for decalcifying sugarcane juice according to claim 5, characterized in that, The volume of a single ion exchange resin column is 1-15 m³. 3 .

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