BE1026862A1 - Process for sugar production line - Google Patents

Abstract

The present invention relates to a method and system involved in sugar production. The invention comprises carrying out, after a pre-liming (20) creating a settling, a purge (22), and an intermediate liming (30) at a temperature of about 68 ° C. Intermediate liming (30) is followed by massive liming (40) without there being any carbonation between them. In addition, the invention proposes to carry out an extraction phase by diffusion (10) at a temperature close to 72 ° C. before the purification phase (100).

Description

Process for sugar production line

Technical area

The present invention relates to a process involved in a production line for producing sugar.

Prior art

A known process for a sugar production line comprises an extraction phase by diffusion and then a purification phase which comprises pre-liming, liming, carbonation and filtration.

[0003] This process does not always make it possible to eliminate all the impurities which are present in the extraction juice following the diffusion. This problem is all the more pronounced nowadays as the beet harvesting campaigns are getting longer and under higher outdoor temperatures, to the point that the storage of beets in silos sometimes reaches more than 300 degree days. This increases the amount of invert and pectin, the amount of bacteria in beets, and the amount of destroyed cells in beets.

Summary of the invention

[0004] One of the aims of the invention is to increase the efficiency of the sugar production line.

[0005] To this end, the invention provides a process for a sugar production line, the process comprising a phase of purifying a liquid, which comprises, in this order:

(a) a first liming, in a first liming equipment, at a first temperature, so as to cause a settling of the liquid, (b) a first purge separating an upper part of the liquid and a lower part of the liquid,

BE2018 / 5885 (c) a transfer to a second liming equipment of the upper part of the liquid, (d) a second liming, in the second liming equipment, at a second temperature, which is preferably substantially equal to the first temperature , (e) a transfer to a third liming equipment, (f) a third liming, in the third liming equipment, at a third temperature, (g) a first carbonation, and (h) a first filtration, in which the second temperature is at least 10 ° C lower than the third temperature.

[0006] The second liming, which can be called intermediate liming, makes it possible to treat more impurities, which increases the yield of the process. It allows the pectin to clot. It allows the formation of colloids. It allows the process to be more flexible with respect to variations in the temperature of the extraction juice. It also helps thin out the liquid.

[0007] The settling allows the impurities to descend to the bottom of the first liming equipment. Impurities, which are in particular in the form of colloids, are thus particularly present in the lower part of the liquid. Following the first purge, the upper part of the liquid, which is therefore less loaded with impurities, is transferred to the second liming equipment.

[0008] The process is preferably part of the chain for producing sugar from sugar beet.

[0009] Preferably, the second temperature is at least 15 ° C lower than the third temperature. Preferably, the third temperature allows carbonation.

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Liming, that is to say the addition of lime (CaO), for example in the form of lime milk (Ca (OH) 2), makes it possible to precipitate the impurities. Carbonation precipitates excess lime with the help of carbon dioxide.

[0011] According to one embodiment of the invention, the method comprises a transfer of the lower part of the liquid to a fifth liming equipment, a fifth liming in the fifth liming equipment, a second purge separating an upper part of the liquid present in the fifth liming equipment and a lower part of the liquid fifth liming equipment, and a transfer to the third liming equipment of the upper part of the liquid present in the fifth liming equipment. [0012] The fifth liming and the second purge remove the colloids and recover the sugar.

[0013] According to one embodiment of the invention, the second temperature is below 68 ° C and / or between 60 ° C and 67 ° C. The second temperature is preferably between 63 ° C and 67 ° C, more preferably between 64 ° C and 66 ° C.

[0014] According to one embodiment of the invention, the third temperature is between 84 ° C and 88 ° C. The third temperature is preferably close to 85 ° C.

[0015] According to one embodiment of the invention, the method further comprises a dosage of hypochlorite between the first liming and the second liming or between the second liming and the third liming.

[0016] According to one embodiment of the invention, the method further comprises, before the purification phase, an extraction phase by diffusion which comprises heating pieces of beets or beet chips in a liquid of extraction at a temperature between 70 ° C and 74 ° C.

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[0017] Preferably, the extraction liquid is an aqueous solution or water. Preferably, the extraction liquid is free from formaldehyde. The pieces of beets can be called cossettes.

[0018] The diffusion extraction phase extracts the sugar from the beet cells by osmosis. The result of the diffusion is a sweet liquid with impurities, which can be called "green juice" or "extraction juice". Using a temperature within the specified range instead of around 68 ° C avoids the use of formaldehyde in the extraction liquid, thus avoiding the presence of formaldehyde in the green juice. This also makes the extraction juice particularly weaker in infectious agents, that is to say more aseptic. However, this can have the consequence of increasing the amount of impurities in the extraction juice.

[0019] According to one embodiment of the invention, the transfer between the second liming equipment and the third liming equipment comprises passage through a heat exchanger.

[0020] The heat exchanger increases the temperature of the liquid during this transfer.

According to one embodiment of the invention, the CaO concentration of the liquid at the outlet of the first liming equipment is equal or substantially equal to the CaO concentration of the liquid at the entrance of the second liming equipment before the 'addition of lime corresponding to the second liming. In other words, there is no carbonation between the first liming and the second liming.

According to one embodiment of the invention, the CaO concentration of the liquid at the outlet of the second liming equipment is equal or substantially equal to the CaO concentration of the liquid at the entrance of the third liming equipment before the 'addition of lime corresponding to the third liming. In other words, there is no carbonation between the second liming and the third liming.

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[0023] According to one embodiment of the invention, the liquid reaches a concentration of 0.350 to 0.400 g CaO / 100 mL during the second liming.

[0024] According to one embodiment of the invention, the liquid is mixed during the second liming, said mixture preferably having a speed of between 1 and 3 revolutions per minute.

[0025] According to one embodiment of the invention, the second liming has a duration of between 10 to 30 minutes, preferably between 15 and 20 minutes.

[0026] According to one embodiment of the invention, the purification phase comprises, after the first filtration, a fourth liming, a second carbonation, and a second filtration.

The third and fourth liming can be described as "massive liming".

The liquid from the second filtration can be called "light juice". [0029] According to one embodiment of the invention, the method further comprises, after the purification phase, evaporation and crystallization.

[0030] The invention further provides a system suitable for use in a sugar production line, comprising a liquid purification system which comprises:

• a first liming equipment to perform a first liming and making it possible to reach a first temperature, • a first purge means making it possible to separate an upper part and a lower part of the liquid present in the first liming equipment, • a second equipment liming to perform a second liming and making it possible to reach a second temperature, which is preferably substantially equal to the first temperature, • a means of transferring the upper part of the liquid to the second liming equipment,

BE2018 / 5885 • a third liming equipment to perform a third liming and making it possible to reach a third temperature, • a liquid transfer means between the second liming equipment and the third liming equipment, • a first carbonation equipment for perform a first carbonation, and • a first filtration equipment to perform a first filtration, in which the second temperature is at least 10 ° C lower than the third temperature.

The first purging means can form part, at least partially, of the first liming equipment. It can be mounted on the first liming equipment or coupled with it.

According to one embodiment of the invention, the system comprises a fifth liming equipment, a means for transferring the lower part of the liquid obtained by the first purging means to the fifth liming equipment, a second means of purge for separating an upper part of the liquid and a lower part of the liquid present in the fifth liming equipment, and a means for transferring to the third liming equipment the upper part of the liquid present in the fifth liming equipment.

According to one embodiment of the invention, the system comprises, upstream of the purification system, extraction equipment by diffusion designed to heat pieces of beets or cossettes in an extraction liquid to a temperature between 70 ° C and 74 ° C.

[0034] According to one embodiment of the invention, the purification system further comprises, downstream of the first filtration equipment, a fourth liming equipment to carry out a fourth liming, a second carbonation equipment to carry out a second

BE2018 / 5885 carbonation, and a second filtration equipment to perform a second filtration.

[0035] The advantages mentioned for the method apply mutatis mutandis to the system according to the invention.

Brief description of the figures

Other characteristics and advantages of the invention will become apparent on reading the following detailed description for the understanding of which reference is made to the appended figures among which:

- Figure 1 shows schematically a method according to an embodiment of the invention, intended for use in a sugar production line, and - Figure 2 schematizes a system for a sugar production line according to an embodiment of the 'invention.

Methods of carrying out the invention

The present invention is described with particular embodiments and references to figures, but the invention is not limited by them. The drawings or figures described are only schematic and are not limiting.

In the context of this document, the terms "first" and "second" etc. are used only to differentiate the different elements and do not imply order between these elements. Furthermore, the presence of a fifth element does not necessarily imply the presence of the first, second, third and fourth elements.

In the figures, identical or similar elements may bear the same references.

[0040] Figure 1 schematically shows a method according to one embodiment of the invention, for use in a sugar production line. FIG. 2 schematically shows a system for a sugar production line according to one embodiment of the invention.

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The method comprises different stages of treatment of a liquid, the nature of which changes as the stages progress. In the context of this document, it is understood that the “liquid” has a composition which can be modified by the steps of the process.

In one embodiment of the invention, the method comprises an extraction phase by diffusion 10 followed by a purification phase 100. The extraction phase by diffusion 10 comprises heating beet pieces or cossettes in an extraction liquid, preferably at a temperature between 70 ° C and 74 ° C. The diffusion extraction phase 1 preferably takes place in diffusion extraction equipment 11.

[0043] The purification phase 100 takes place in a purification system 101.

[0044] The purification phase comprises a first liming 20. This takes place at a first temperature and in a first liming equipment 21.

The first liming 20 may be called pre-liming 20. It preferably comprises a gradual alkalinization, for example by gradual addition of lime. The first liming equipment 21 is for example an alkalinization column. The first liming equipment 21 can comprise several compartments, for example five compartments, corresponding to increasing alkalinities. In one embodiment of the invention, the first liming 20 allows a concentration of 280 g CaO / 100 mL to be increased. The first liming 20 preferably lasts between 10 and 30 minutes, more preferably between 15 and 25 minutes, even more preferably between 19 and 21 minutes.

The first liming 20 generates a settling of the liquid present in the first liming equipment 21. The settling creates a differentiation of the composition of the liquid as a function of the height.

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The first liming 20 is followed, preferably directly, by a first purge 22 which separates the liquid present in the first liming equipment 21 into an upper part 25 and a lower part 26. The first purge 22 is carried out by a first means of purging.

[0048] Following the first purge 22, the upper part 25 of the liquid is transferred to a second liming equipment 31. This transfer can include the addition of hypochlorous acid to the liquid. Preferably, the CaO concentration of the liquid is unchanged during this transfer, so that the CaO concentration of the liquid leaving the first liming equipment 21 is equal or substantially equal to the CaO concentration of the liquid entering the second liming equipment. 31.

The liquid present in the second liming equipment 31 is subjected to a second liming 30 there, at a second temperature. The second temperature is preferably equal to the first temperature.

The second liming 30 comprises an addition of lime, for example to obtain, at the end of this step, a concentration of 400 g CaO / 100 mL. Preferably, the second temperature is lower than 68 ° C and / or between 60 ° C and 67 ° C. The second liming 30 preferably has a duration of between 10 to 30 minutes, more preferably between 15 and 20 minutes.

Preferably, the second liming equipment 31 has a capacity which represents approximately 50% of the draw-off volume of the diffusion extraction equipment 11. Preferably, the second liming equipment comprises a mixing system which allows mixing of the liquid during the second liming 30. This mixing is preferably carried out at a speed between 1 and 3 revolutions per minute.

The second liming 30 is followed, preferably directly, by a transfer of liquid between the second liming equipment and the

BE2018 / 5885 third liming equipment 41. This transfer can include passage of the liquid through a heat exchanger.

In one embodiment of the invention, the CaO concentration of the liquid is unchanged during this transfer, so that the CaO concentration of the liquid at the outlet of the second liming equipment 31 is equal or substantially equal to the CaO concentration of the liquid at the inlet of the third liming equipment 41.

In one embodiment of the invention, the lower portion 26 of liquid obtained by the first purge 22 is transferred to a fifth liming equipment 131 to undergo a fifth liming 130 there. The fifth liming equipment 131 may by example have a capacity of about 10% of the withdrawal capacity of the diffusion extraction equipment 11.

The fifth liming 130 is followed, preferably directly, by a second purge 132 which separates the liquid present in the fifth liming equipment 131 into an upper part 135 and a lower part. The second purge 132 is carried out by a second purge means. The upper part 135 of the liquid present in the fifth liming equipment 131 is then transferred to the third liming equipment 41.

[0056] Preferably, this transfer brings the upper part 135 of the liquid present in the fifth liming equipment upstream of the heat exchanger.

The liquid entering the third liming equipment 41 then comes partly from the second purging means and partly from the second liming equipment 31.

The liquid present in the third liming equipment 41 is subjected to a third liming 40 there, at a third temperature. The third liming includes an addition of lime, for example to obtain, at the end of

BE2018 / 5885 this step, a concentration of 0.900 g CaO / mL. The third liming can be qualified as "massive liming".

[0059] The third temperature is at least 10 ° C higher than the second temperature. The third temperature is preferably at least 20 ° C higher than the second temperature. Preferably, the third temperature is between 84 ° C and 88 ° C.

The third liming 40 is followed, preferably directly, by a transfer of liquid to a first carbonation equipment 51 where the liquid undergoes a first carbonation 50. The first carbonation 50 allows for example to obtain a pH of 11 and a concentration of 0.080 g CaO / 100 mL.

The first carbonation 50 is followed, preferably directly, by a transfer of liquid to a first filtration equipment 61 where the liquid undergoes a first filtration 60.

The first filtration 60 is followed, preferably directly, by a transfer of liquid to a fourth liming equipment 71 for a fourth liming 70. The fourth liming 70 comprises an addition of lime, for example to obtain, at the end of this step, a concentration of 0.150 g CaO / 100 mL.

The fourth liming 70 is followed, preferably directly, by a transfer of liquid to a second carbonation equipment 81 for a second carbonation 80. The second carbonation 80 allows for example to obtain a pH of 9.3 and a concentration of 0.020 g CaO / 100mL.

The second carbonation 80 is followed, preferably directly, by a transfer of liquid to a second filtration equipment 91 for a second filtration 90.

[0065] Preferably, the purification phase 100 comprises steps 20 to 90. The purification phase 100 is preferably followed by evaporation

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110 in 111 evaporation equipment and 120 crystallization in 121 crystallization equipment.

[0066] In other words, the invention relates to a method and a system involved in sugar production. The invention preferably comprises carrying out, after a pre-liming 20 creating a settling, a purge 22, and an intermediate liming 30 at a temperature of about 68 ° C. Intermediate liming 30 is followed by massive liming 40 without there being any carbonation between them. In addition, the invention proposes to perform an extraction phase by diffusion 10 at a temperature between 70 ° C and 74 ° C before the purification phase 100.

The present invention has been described in relation to specific embodiments, which have a purely illustrative value and should not be considered as limiting. In general, the present invention is not limited to the examples illustrated and / or described above. The use of the verbs "to understand", "to include", "to include", or any other variant, as well as their conjugations, can in no way exclude the presence of elements other than those mentioned. The use of the indefinite article "un", "une", or of the definite article "the", "the" or "Γ", to introduce an element does not exclude the presence of a plurality of these elements. Reference numbers in the claims do not limit their scope.

Claims (15)

Claims 1. A process for a sugar production line, the process comprising a purification phase (100) of a liquid, which comprises, in this order: (a) a first liming (20), in a first liming equipment (21), at a first temperature, so as to generate a settling of the liquid, (b) a first purge (22) separating an upper part (25) of the liquid and a lower part (26) of the liquid, (c) a transfer to a second liming equipment (31) of the upper part (25) of the liquid, (d) a second liming (30), in the second equipment liming (31), at a second temperature, which is preferably substantially equal to the first temperature, (e) a transfer to a third liming equipment (41), (f) a third liming (40), in the third liming equipment (41), at a third temperature, (g) a first carbonation (50), and (h) a first filtration (60), in which the second temperature is at least 10 ° C lower than the third temperature. 2. Method according to claim 1, comprising: • a transfer from the lower part (26) of the liquid to a fifth liming equipment (131), • a fifth liming (130) in the fifth liming equipment (131), BE2018 / 5885 • a second purge (132) separating an upper part (135) and a lower part of the liquid from the liquid present in the fifth liming equipment (131), • and a transfer to the third liming equipment (41) of the upper part (135) of the liquid present in the fifth liming equipment (131). 3. A method according to any preceding claim, wherein the second temperature is below 68 ° C and / or between 60 ° C and 67 ° C. 4. A method according to any preceding claim, wherein the third temperature is between 84 ° C and 88 ° C. 5. Method according to any one of the preceding claims, further comprising an assay of hypochlorite between the first liming (20) and the second liming (30) or between the second liming (30) and the third liming (40). A method according to any one of the preceding claims, further comprising, before the purification phase (100), a diffusion extraction phase (10) which comprises heating pieces of beets in an extraction liquid. at a temperature between 70 ° C and 74 ° C. 7. A method according to any preceding claim, wherein the transfer between the second liming equipment (31) and the third liming equipment (41) comprises passage through a heat exchanger. BE2018 / 5885 8. Method according to any one of the preceding claims, wherein the CaO concentration of the liquid at the outlet of the first liming equipment (21) is equal or substantially equal to the CaO concentration of the liquid at the entrance of the second equipment. liming (31). 9. A method according to any preceding claim, wherein the CaO concentration of the liquid at the outlet of the second liming equipment (31) is equal or substantially equal to the CaO concentration of the liquid at the entrance of the third equipment. liming (41). 10. A method according to any preceding claim, wherein the liquid reaches a concentration of 0.350 to 0.400 g CaO / 100 mL during the second liming (30). 11. Method according to any one of the preceding claims, in which mixing of the liquid is carried out during the second liming (30), said mixture preferably having a speed of between 1 and 3 revolutions per minute. 12. Method according to any one of the preceding claims, in which the second liming (30) has a duration of between 10 to 30 minutes, preferably between 15 and 20 minutes. 13. Method according to any one of the preceding claims, wherein the purification phase (100) comprises, after the first filtration (60), a fourth liming (70), a second carbonation (80), and a second filtration. (90). BE2018 / 5885 14. A method according to any preceding claim, further comprising, after the purification phase (100), evaporation (110) and crystallization (120). 15. A system for a sugar production line, comprising a purification system (101) of a liquid which comprises: • a first liming equipment (21) for carrying out a first liming (20) and making it possible to reach a first temperature, • a first purge means making it possible to separate an upper part (25) and a lower part (26) of the liquid present in the first liming equipment (21), • a second liming equipment (31) for carrying out a second liming (30) and making it possible to reach a second temperature, which is preferably substantially equal to the first temperature, • a means for transferring the upper part (25) of the liquid to the second liming equipment (31), • a third liming equipment (41) to carry out a third liming (40) and allowing a third temperature to be reached, • a liquid transfer means between the second liming equipment (31) and the third liming equipment (41), • a first carbonation equipment (51) for carrying out a first carbonation (50), and • a first equipment t filtration (61) to achieve a first filtration (60), in which the second temperature is at least 10 ° C lower than the third temperature.