Classifications

• • C—CHEMISTRY; METALLURGY
  • C13—SUGAR INDUSTRY
  • C13B—PRODUCTION OF SUCROSE; APPARATUS SPECIALLY ADAPTED THEREFOR
  • C13B30/00—Crystallisation; Crystallising apparatus; Separating crystals from mother liquors ; Evaporating or boiling sugar juice
  • C13B30/02—Crystallisation; Crystallising apparatus
  • C13B30/022—Continuous processes, apparatus therefor
• • C—CHEMISTRY; METALLURGY
  • C13—SUGAR INDUSTRY
  • C13B—PRODUCTION OF SUCROSE; APPARATUS SPECIALLY ADAPTED THEREFOR
  • C13B30/00—Crystallisation; Crystallising apparatus; Separating crystals from mother liquors ; Evaporating or boiling sugar juice
  • C13B30/02—Crystallisation; Crystallising apparatus
  • C13B30/026—Discontinuous processes or apparatus therefor

Definitions

• the present invention relates to a process and a device for continuously kneading a cooked mass obtained in particular during the manufacture of sugar, it being understood that by “sugar” is meant “sucrose”.
• Sugar extraction processes generally use two types of factories: actual manufacturing factories (sugar refineries) and post-processing factories (refineries) in which the sugars are refined, filtered, crystallized and shaped.
• the sugar factories have equipment adapted to the raw material used which is beet or cane.
• the sugar factories have specific equipment while the refineries process raw sugars whether they are cane or beet.
• the diffusers are devices in which water is circulated against the current.
• the juices obtained contain approximately 11 to 12% of impurities related to dry matter.
• a lime treatment followed by carbonation and separation by filtration or decantation allows satisfactory purification of organic non-sugars.
• the present invention relates more particularly to the steps per ⁇ putting to crystallize sugar and applies to all sugary juices whatever the raw material used.
• crystallization in candy and in refinery (cane or beet) is to extract in crystallized form, with as high a yield as possible, the sugar dissolved in the syrup and to thus separate soluble impurities which accompany it.
• the speed of crystallization depends mainly on the following linked parameters: supersaturation, viscosity, temperature, internal agitation, purity and pH.
• French patent n ° 1528738 describes a crystallization process for candy syrup according to which concentrated sweet juices are introduced into a cooking boiler where a fraction of the sugar is crystallized. The cooked mass obtained is kneaded for a certain time at an elevated temperature and then sieved in a centrifugal wringer where the crystals are separated from the sewer. The mother sewer is then mixed with crystals and then undergoes a second kneading in order to cause the crystallization of the sugar contained in said sewer.
• French patent n ° 2064277 describes a process for obtaining crystals continuously according to which a sugar syrup, in the presence of crystalline seeds, previously added, is concentrated under vacuum in a crystallizer having several successive compartments. This process requires a relatively high temperature, which on the one hand, increases the energy expenditure, and on the other hand, decreases the crystallization yield.
• the crystallization process according to the invention makes it possible to obtain, at the end of the kneading of the baked mass, a much greater quantity of crystallized sugar than during the implementation of the processes known to date.
• the process aims to lower the temperature of the cooked mass as much as possible to increase crystallization.
• It consists in subjecting a sugar syrup to continuous or discontinuous cooking in order to obtain a cooked mass, to subject the cooked mass to one or more stages of continuous mixing under vacuum, then to separate the crystals from the mother water.
• the crystallization jet considered, in particular by turbination and is characterized in that at least part of the mother liquor is recycled during the steps of the kneading under vacuum.
• the invention also relates to a device for kneading a baked mass, consisting of one or more kneaders arranged in series comprising means for input and output of the baked mass, at least one vacuum outlet characterized in that that the mixer (s) include a means for entering the mother liquor obtained during the spinning of the crystallized cooked mass.
• the so-called “poor sewer” part is recycled during the steps of kneading under vacuum.
• the so-called “rich sewer” part is reinjected for example at the cooked level.
• the recycled part of the mother liquor is heated and demulsified before said recycling.
• the viscosity of the cooked mass increases, the lowering of temperature is made possible by the self-evaporation under vacuum, in continuous mode, of the water contained in the cooked mass and by the recycling of all or part of the mother water, which causes violent and permanent agitation.
• the continuous mixing under vacuum comprises several successive stages. In the case of two stages, the first is conducted under a vacuum between 82.6 MPa and 88.0 MPa, the second under a vacuum between 88.0 MPa and 96.0 MPa.
• the terracotta must have an initial temperature of around 80 ° C and, after continuous mixing under vacuum, have its temperature lowered to between 40 ° C and 50 ° C.
• the crystallized terracotta is then wrung (turbination): the crystals are separated from the mother liquor and the poor sewer of the crystallization jet under consideration is recycled, for the most part, at the level of the continuous mixer (s) under vacuum . Poor recycled sewers maintain sufficient fluidity so that the cooked mass does not freeze and the mobility of the crystals allows their movement.
• the means for entering the lean sewer consist of one or more pipes located in the lower part of the cylinder.
• these tubes arrive tangentially to the cylinder.
• their number is between two and ten.
• Figure 1 shows a flow-sheet of a variant of the process according to which, after continuous cooking, the continuous mixing under vacuum is carried out in an apparatus consisting of a single mixer.
• Figure 2 presents a flow-sheet of a preferred variant of the process according to which, after continuous cooking, the continuous mixing under vacuum is carried out in an apparatus made up of two distinct mixers.
• Figure 3 shows the device for implementing the method illustrated in Figure 1.
• WIPO Figure 4 shows the device for implementing the method illustrated in Figure 2.
• FIG. 5 is a cross-sectional view in broken section with a parallel plane of a vacuum mixer illustrated in FIG. 4.
• Figure 6 is a side view along A. A of the same mixer.
• a fraction 1 a, 21 a of sugar syrup 1, 21 is directed towards a vertical device 2, 22 to make the cooked potato. It has a volume of 300 h. l. and comprises a bundle, with tubes supported by two frusto-conical plates, sloping towards the central well equipped with a stirring propeller.
• the cooking feet 3, 23 of the vertical device 2, 22 supply the magma mixer 4, 24.
• the magma mixer is a completely closed horizontal cylindrical capacity, equipped with an agitator consisting of a propeller supported by a longitudinal shaft rotating at 1 rpm and equipped with a double jacket with circulation of hot water at 80 ° C. allowing to thermostate the whole: this magma mixer has only a buffer storage role.
• the continuous cooking appliance 6, 26 is composed of a horizontal cylindrical steel tank, inside which the heating is provided by a bundle of longitudinal stainless steel tubes, arranged in layers.
• the lower part of the tank is provided with a double envelope in which the vapors circulate which are not condensed in the bundle.
• a certain flow of steam is injected into the lower part of the cooking apparatus to ensure agitation of the cooked mass.
• the apparatus is divided into compartments by transverse partitions and a longitudinal partition at the base of which an orifice allows the progression of the cooked mass.
• the first compartment is powered
• CMPI by the magma, the following by the baked mass from the previous compartment.
• Each compartment is also provided with a syrup supply 1 b, 21 b which sprinkles the walls emerging from the cooked mass by rotating tubes.
• the massecuite reaching the last compartment is extracted at its base by a variable speed pump.
• the circulation and the flow of fluids in the device are controlled by chains of vacuum regulation, vapor pressures, agitation, density and level of cooked mass.
• Average aperture of the crystals 0.5 to 0.6 mm
• the terracotta 7, 27 is directed to a continuous vacuum mixing device 8, 28.
• this device consists of a mixer 8 comprising a hermetic horizontal shell 9, heat-insulated, provided with a longitudinal shaft 10 supporting a propeller 1 1 and separated into two compartments 12 , 13, by a watertight wall 14, which is equipped in the lower part with an orifice 15 allowing the transfer of the baked mass from an inlet compartment to the outlet compartment, each compartment being provided with a tube 35 allowing a connection with a vacuum source.
• the inlet compartment and the outlet compartment are respectively provided with inlet manifolds 1 16a and 1 6b of output of the massecuite, these tubes being of small cross section and located in the lower part of each compartment,
• the first compartment is subjected to a vacuum of 82.2 MPa, the second to a vacuum of 89.4 MPa.
• variable speed positive displacement pump - which can be the pump for extracting the continuous cooked 6 - and d an umometric volumetric pump with variable speed of extraction.
• the baking mass is fluidized with the lean sewer 18 obtained during the spinning of the crystallized baking mass (centrifugation step 40 allowing the crystallized sugar to be isolated 41 ).
• This poor sewer arrives at the bottom of each of the compartments 12, 13 by three tangential pipes 19 whose flow rates are regulated.
• the crystallized baked mass 27 leaving the first continuous vacuum mixer 28 is directed to the second mixer 29.
• Each mixer 28, 29 consists of a horizontal cylinder 30 provided with an internal movement of low power, scraping the walls and thus preventing sugar concretions, it also comprises inlet pipes 31a and outlet 31b of the terracotta, of small section and located in its lower part.
• the level of cooked mass is maintained substantially in the diametral plane, so as to present the maximum surface area for evaporation.
• the part known as "poor sewers" 39 resulting from the cooked mass after spinning 40, previously reheated 42 and demulsified 43, is injected 211 a, 211 b, into the mixers 28, 29 at four points by horizontal inlets 32 distributed according to the lower generator 33.
• the so-called "rich sewer” part 44 is recycled with the fraction 21 b.
• Each mixer 28, 29 constitutes a stage placed under a determined vacuum, which corresponds to the desired cooked-up temperature. The progression of the vacuum per stage makes it possible to lower the lower temperature limit while avoiding the spontaneous formation of "false grains".
• the assembly is continuously supplied by a volumetric pump 34 at variable speed from the outlet of a continuous batch or of a mixer for casting a batch batch.
• Each stage is connected 35 to a deep vacuum unit 37, the vacuum being regulated by means of an automatic valve 36. After a 90 minute residence time, the cooled cooked mass is extracted continuously through a volumetric pump 38 speed will ⁇ riable.
• the speeds of the terracotta pumps are controlled by level regulators.
• the voids are regulated by automatic valves on posted instructions.
• the sewer introduction flow rate on each stage is adjusted proportionally to the mass flow rate and corrected on the last stage as a function of the output Brix.
• the process according to the invention makes it possible to save approximately 60% of the steam consumption.
• the essential difference between the continuous vacuum mixer and the other types of crystallizer is that the cooling is not done by exchange with a fluid but by auto-evaporation.
• the continuity of the operation promotes the regularity of the finished product obtained by maintaining the value of all the parameters of the regulatory chains.
• the magnification coefficient of the crystals is between 1.30 and 1.80.
• the crystallization process according to the invention can be qualified as “crystallization process cold ": it eliminates any phenomenon of recoloration of the cooked mass, thereby reducing the amount of water required during the clearing step, an operation which is always accompanied by a redissolution of the sugar crystals.
• the process and the crystallization apparatus of such a sugar rop 'according to the invention allow to push the extraction to a level never achieved, regardless of the technique used.
• they add to the kneading all the advantages of a continuous * work , namely: regularity of operation - therefore better quality of the product obtained -, reduction of the dimensions of the material, simplification of the control and automation chains , very significant improvement in the workshop's operating account.

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• Chemical & Material Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• Biochemistry (AREA)
• Organic Chemistry (AREA)
• Saccharide Compounds (AREA)
• Confectionery (AREA)
• Food-Manufacturing Devices (AREA)

Applications Claiming Priority (2)

Publications (2)

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ID=9278352

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Cited By (1)

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Family Cites Families (5)

• 1982
  • 1982-10-18 FR FR8217408A patent/FR2534595B1/fr not_active Expired
• 1983
  • 1983-09-26 ES ES525934A patent/ES525934A0/es active Granted
  • 1983-09-30 IE IE2326/83A patent/IE56053B1/en not_active IP Right Cessation
  • 1983-09-30 DE DE8383902997T patent/DE3365320D1/de not_active Expired
  • 1983-09-30 JP JP83503081A patent/JPS60500041A/ja active Pending
  • 1983-09-30 WO PCT/FR1983/000196 patent/WO1984001584A1/fr active IP Right Grant
  • 1983-09-30 DE DE198383902997T patent/DE121522T1/de active Pending
  • 1983-09-30 EP EP83902997A patent/EP0121522B1/de not_active Expired
  • 1983-10-06 CA CA000438516A patent/CA1205803A/fr not_active Expired
  • 1983-10-17 PT PT77514A patent/PT77514B/pt not_active IP Right Cessation
  • 1983-10-17 IT IT68071/83A patent/IT1160223B/it active
• 1984
  • 1984-02-22 DK DK86984A patent/DK86984A/da not_active Application Discontinuation

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