MXPA97006618A - Method for recovering an organic compound apparatus of solution - Google Patents

Abstract

The present invention relates to a method for recovering a crystallizable organic compound from a solution containing said compound, the crystallization compound comprising nucleating from a solution having a viscosity of at least about 100,000 CP and a supersaturation. less than about 4 with respect to the compound to be recovered, under conditions that include a continuous intermixing to and from the higher cutting zones and a slow cooling rate of about 10-100 effective hours to promote nucleation without a substantial growth of the crystal and recovering a crystalline mass

Description

I BEGIN TO RECOVER AN ORGANIC COMPOSITION FROM SOLUTIONS The present invention relates to a method by which a crystallizable organic compound can be recovered from solutions containing said compound. In particular, the invention relates to a method by which water-soluble organic compounds can be crystallized from aqueous supersaturated solutions having a very high viscosity and then recovered from the solutions. The two main steps of crystallization are the formation of crystal sowing (nucleation) and the growth of the crystal. In most industrial processes, crystallization is mainly based on crystal growth. The cutting-edge technology with respect to crystallization is represented by, for example, Athlouthi, M. and Reiser, P. (ed.), Sucrose, Properties and Applications, Blackie Academic & Professional, Suffolk, Great Britain, 1995, page 49 ff. This description explains the mechanism of crystallization with respect to both the nucleation and the growth of the crystal. With respect to the industrial crystallization of sucrose, this publication establishes, for example, that one must avoid the concentration of the solution to the nucleation zone, that is, the zone in which the spontaneous formation of nuclei occurs easily (page 58). ); one must avoid the creation of an uncontrolled number of seeds (page 59); crystals can not be increased to a percentage of mother liquor beyond a certain value (pages 59-60); and crystallization should be performed in the metastable zone not too close to the nucleation zone and the saturation curve (pages 60-61, and pages 63-64). The metastable zone is the area where the spontaneous crystal formation will occur only if the crystals are present. It is emphasized that in this area no new crystals are formed in the absence of seeds. In addition, in accordance with this publication (see, for example, pages 57 and 58), the impurities decrease the growth rate of the crystal and may even block growth completely. With an increase in supersaturation and a decrease in the temperature of the solution, the viscosity of the solution also increases, thereby retarding and eventually completely blocking the diffusion of the molecules through the liquid layer around the crystals or crystal cores towards the surface of the crystal, and therefore prior art processes based on crystal growth are no longer possible. In accordance with the prior art, high viscosity has also been referred to as a clear impediment to the separation of the crystals from the mother liquor. With regard to the crystallization of sucrose, these problems have also been discussed in the previous publication Mathlouthi,. and Reiser, O. (ed.), Sucrose, Properties and Applications. The methods for recovering sucrose employed in the sugar industry typically comprise three successive steps of crystallization. In the last step, which is known as crystallization 'C, the sucrose content of the syrup of the starting material is about 73-75 percent in the dry substance; this method of crystallization is slow and difficult, and yet the purity of the sucrose (percent sucrose in the dry substance) of the runoff, i.e., molasses, obtained therefrom is still typically as high as about 58 percent . There are different methods by means of which it is sought to improve the sucrose production, that is, to reduce the purity of the sucrose of the molasses. Such methods include the Quentin and Steffen methods and the molasses fractionation methods of the type described in Finnish Patent 77 845 (Suomen Sokeri Oy, Heikkila, Elaja, Millner, Virtanen, corresponds to published international application WO 81/02420). Such fractionation methods enable a fraction enriched with betaine from which the betaine that will be obtained from the molasses can be recovered.

In conventional methods, it has only been possible to crystallize the xylose, if the purity of the xylose has been at least about 70 weight percent in the dry substance. In this regard, it has been necessary to first purify the obtained xylose-containing solution, for example, as a result of the hydrolysis of plant-derived material to a required degree of purity by different methods of ultrafiltration, ion exchange, discoloration, exclusion of ions or chromatographic separation or combinations thereof; In addition, auxiliary solvents that reduce the solubility of xylose to crystallize xylose have been used. The above methods of separation, purification and crystallization of xylose have been described, for example, in the Patents of the United States of America Numbers 4 631 129 (Heikkilá, H., Suomen, Sokeri Oy), 4 075 406 (Melaja, A. J. and Hámáláinen, L., Suomen Sokeri Oy), 5 084 104 (Heikkilá, H. and Hyóky, G.; Cultor, Ltd) and 4 168 988 (Riehm, T. and Hoefenk, G., Institut voor Bewaring in Verwerking van Landbouwprodukten) and the publications referred to therein. When the xylose is prepared by hydrolyzing the xylan, an alternative to the above methods is to purify the xylan before hydrolyzing it to xylose to obtain a xylose solution of sufficient purity. This procedure is also very complex and difficult to handle, as will be apparent from Browning, BL, Methods of wood chemistry, II Interscience Publishers, New York, 1967, and Fry, SC, The growing plañí cell wall: chemical and meiabolic analysis, Longman Scientific & Technical, England, 1988. According to German Offenlegungsschrift 1 643 940 (Eickenmeyer, R. and Scholler, H.), crystalline xylose is recovered from a pentosan hydrolyzate - and natural substances containing cellulose by crystallization from a syrup containing at least 70 percent xylose. The syrup is introduced into a crystallizer at 60-70 ° C, and a glass mass containing 15-33 percent xylose in the amount of xylose delivered to the crystallizer is taken from the crystallizer at 48-52 ° C. f, e separate the crystals from this crystal mass by centrifugation, and the mother liquor, the amount of which is 300-100 percent of the fresh syrup supplied to the system, is combined with the hydrosylate of the starting material. The resulting mixture of the mother liquor and the hydrosylate is treated in a cation exchanger and anion exchanger, and after a subsequent decolorization treatment, the mixture is evaporated in order to obtain a syrup to be supplied to the crystallizer. In addition to the difficult to handle purification treatments, the method thus comprises a very extensive recycling. According to this publication, the small amount of xylose obtained in a crystallization (the small yield as compared to the xylose supplied to the crystallizer) is due to the fact that when the temperature drops below about 48 ° C, the Crystallization will be very small due to the fact that the viscosity of the solution increases substantially when the temperature drops. U.S. Patent No. 3,981,739 (Dmitrovsky et al., Amstar Corporation) refers to a method of continuous crystallization of sugars (sucrose, dextrose, fructose, lactose, carbohydrates). The method involves the controlled growth of crystals in a two-step evaporative crystallization starting with the small-sized seed crystals. The crystals in the first stage are substantially larger than the seed crystals, and the crystals of increased size are produced in the second stage. U.S. Patent Number 4199373 (Dwivedi et al., Chimicassa GmbH) refers to a process for making free-flowing mixtures of fructose and glucose avoiding the disadvantages of previous processes (such as the need for sophisticated machinery and control ^ careful, high energy costs and low performance). The process is a method of solidification; it does not include the separation of the crystals and the mother liquor. A highly concentrated solution is sown and allowed to stand (thus allowing crystallization to take place) at a specific temperature and relative humidity, it is recovered, dried and milled. Too low a concentration results in a doughy mass, too high a concentration results in a glassy mixture. It is essential that the surrounding air has a relative humidity below 50 percent and a temperature between 50-90 ° F (10-32 ° C). Other total solidification processes are described, for example, in U.S. Patent Nos. 4,297,146 (Mise et al., - CPC International Inc.), 4595418 (Yoshino; Sanwa Kosan Kabushiki Kaisha) and 4,640,717 ( Shukla et al; Tate &Lyle Public Limited Company). The Patent of the United States of North America Number 4 634 472 (Niekamp et al., A.E. Staley Manufacturing Company) provides a process for making an enriched fructose syrup. In this process the appropriate temperature of a feeding syrup (75-89 percent) is established for the crystallization of glucose. It is well known in the art that the simple crystallization of glucose, even at low purity, is frequently a problem, as for example in the case of honey (typical solid concentration of 81-85 percent, approximately 40 percent of glucose and approximately 30 percent fructose in dry sol. It is also known (Harold E. Horn, "Dextrose: An Alternative to Sucrose in Panned Confections", The Manufac- turing Confederation for 1977) that the crystallization of glucose is increasingly inhibited at viscosities of 10,000-100,000 cP. (10-100 Pas). Calculated from Example 1 of U.S. Patent Number 4 634 472, the crystallization viscosity is only about 2000 cP, which represents a solution of very low viscosity. Water can not be used as a diluent in the process according to U.S. Patent No. 4 634472 (column 5, lines 20-25), since the crystals would dissolve. U.S. Patent No. 4,816,079 (Ahrens et al., Fried Krupp GmbH) refers to a process for the continuous crystallization of dextrose monohydrate. The process is, in principle, a traditional cooling crystallization method based on crystal growth. Part of the feed syrup undergoes a cutting process for a period of 0.01-2 seconds to initiate nucleation to produce the seed crystals for the process. In accordance with the foregoing, there is a need for an economical and efficient process to achieve a high recovery of the crystalline product from a solution containing the same, especially a source, having lower levels of crystallizable product than those which are directly processable under comparable conditions to achieve the same performance. It is therefore a principal objective of the invention to achieve an improvement in the total production of the crystallizable organic compounds recovered from solutions containing them. It is an additional objective to economically use in said processes impure material streams in the crystallizable organic compounds contained therein. It is also an objective to employ the runoff or recycle stream of industrial processes containing crystallizable organic compounds as a source for efficient recovery of such compounds with good performance. It has now been found that crystallizable organic compounds forming solutions having a high viscosity can be recovered from said solutions by crystallization when the supersaturation value is substantially realized by means of nucleation, ie in such a way that the growth of the crystal is not significant in the process. In this way, the compounds can still be crystallized from comparatively impure solutions from which they could not be crystallized beforehand. In the context of the present description and claims, a high viscosity denotes a viscosity in which the growth of the crystal is substantially delayed. Specifically, in the present invention, a solution is considered to have a high viscosity if its viscosity is in the range of about 105 cP to about 106 cP (100-1000Pas). The invention thus provides a method for recovering a crystallizable organic compound from solutions containing said compound, characterized in that the compound is substantially crystallized by nucleation from a solution having a high viscosity and a high supersaturation with respect to to the compound that is going to recover, and in which the crystals formed are recovered. The crystallization of the invention is preferably carried out beyond the metastable zone, ie, using the terminology of Mathlouthi, M. and de Reiser, P. (ed.), Sucrose, Properties and Application for example, in the nucleation zone which according to said publication, should be avoided in the crystallization of sucrose, for example. In the method of the invention, nucleation is improved by effective agitation, thereby enabling nucleation to occur spontaneously. The agitation is carried out as vigorously as the high viscosity allows to achieve an efficient continuous intermixing of the portions of the crystallization mass towards and from the higher cutting zones in which nucleation is favored in order to maximize the crystallization through of the mass. In this way, the solidification of the crystallization mass is prevented, and the nuclei can develop the shape of the crystal and grow until the growth of the crystal is blocked, whereby the highest yields are realized. To induce nucleation, the seed crystals can also be added to the supersaturated solution. The size of the final crystal is typically limited to about 10-120 microns. The improvement in the recovery of the crystallizable compound achieved by the present invention is based fundamentally on a nucleation mechanism in highly viscous solutions under continuous intermixing whereby the production of total crystallization is maximized. After nucleation has been initiated, the high viscosity of the mother liquor of the suspension (i.e., the crystallization mass) obtained substantially prevents crystal growth and discharge from the supersaturation state; however, nucleation continues due to effective agitation. During the first period of the nucleation process of the present invention, the suspension is cooled until reaching and maintaining a high supersaturation of the mother liquor. After this, the temperature of the crystallization mass and the concentration of the total solids are practically constant. The supersaturation of the mother liquor remains high during the entire crystallization phase, that is, the system remains substantially constant over the metastable range. In the present description and claims, the supersaturation of the solution denotes its apparent supersaturation with respect to the organic compound to be recovered, that is, the dimensionless proportion of the measured content and the solubility of said compound, which is calculated by the equation: s = content of the compound in the solution shows solubility of the compound at the temperature of the sample solution where s is supersaturation, and the unit of measure for the content and solubility of the compound is gram of pure compound / 100 grams of solvent. Also the terms "supersaturated" and "supersaturation" refer individually to the saturation of the solution with respect to the compound to be recovered. The purity of the substance denotes its percentage in the dry substance. The high supersaturation denotes a supersaturation in which the nucleation process is dominant and crystal growth is inhibited. Typically, in the present invention a solution is considered to have a high supersaturation when s is between 1.4 and 4. In the prior art it is known that a relatively high supersaturation is needed for nucleation, and that this is maintained in the most efficient manner. efficient at a low viscosity by the application of vigorous mixing. If nucleation is preferred as such, then the obvious operating conditions. they would be a relatively low viscosity and vigorous mixing. Contrary to this, high viscosities are used in the present invention, by means of which a higher recovery of the crystallizable compound can be obtained. In accordance with the prior art, also the problems involved in the separation of the small crystal product from a mother liquor at a high viscosity of the crystallization mass have hampered the industrial application of crystallization based mainly on nucleation. The vigorous nucleation (spontaneous crystal formation) is typically considered as a failure in traditional crystallization processes. In accordance with a further aspect of the invention, however, the small crystal product produced in the nucleation of the crystallization mass can be separated when the viscosity of the crystallization mass is lowered immediately before the recovery of the crystals or in connection with the crystallization. with the recovery of the crystals. The viscosity can be reduced, for example, by heating the mass of the crystal and / or diluting it either with a diluted starting material solution or with the solvent contained therein. The addition of another solvent in which the crystals do not dissolve substantially is also possible; for example in the recovery of sucrose, glycerol can be used as said solvent. A special embodiment of the invention is the recovery by filtration of a small crystal fraction obtained by nucleation. In the crystallization processes typical of the prior art, considerable quantities of the product are lost in the final mother liquors. The present invention leads to remarkable additions in the recovery of the desired product from the mother liquor. The recovered material can be further refined by traditional crystallization processes. The typical improvement achieved by the present invention in the total production is 5-30 percent or even more compared to the processes of the prior art, and total yields of up to 80 percent can be obtained from aqueous solutions where The traditional crystallization np is effective. The method of the invention is particularly suitable for the recovery of carbohydrates, which are preferably easily crystallizable such as aldoses and alditols, for example sugars and sugar alcohols, and hydroxy and amino acids and betaine of aqueous solutions thereof. The term "aqueous solution" as used herein denotes a medium wherein the crystallizable compound is initially dissolved, thereby providing a single, homogeneous continuous phase containing a sufficient concentration of the crystallizable compounds such that when the solution is concentrated its supersaturation state, nucleation occurs easily. It is understood that the aqueous solution may comprise other substances miscible therewith either as impurities in the feed or as adjuvants to facilitate further processing. Since the method can recover these compounds even from substantially impure solutions, it is suitable for use in the recovery of organic compounds from aqueous solutions derived from biomass. Said solutions include molasses and vinasse, biomass hydrolysates or parts thereof or concentrates obtained therefrom, such as cooking liquors from the pulp industry. Such aqueous solutions also include the run-off (mother liquors from which the crystals have been separated) obtained in the industrial crystallization processes of the present day in which the purity of the compound to be recovered in the raw material solution it is comparatively high and the impurities are discharged in the runoff. On the other hand, this method is suitable for the recovery of products prepared by means of fermentation, such as gluconates, glutamates and lactic acid, from fermentation solutions thereof. The method of the invention is suitable for the recovery of, for example, the following compounds: xylose, mannose, xylitol, mannitol, lactose, lactitol, sucrose, glucose, fructose, maltose, maltitol, isomaltose, isomaltulose, lactulose, aD-glucopyranosyl (l 6) mannitol, α-D-glucopyranosyl (1 6) sorbitol, β-cyclodextrin, itaconic acid, citric acid, betaine, inositol, 1,4-anhydroglucitol. The method of the invention is particularly advantageous in cases where the crystallizable substance has been recovered from solutions by crystallization by known methods to the extent technically feasible or economically feasible. In other words, the method is particularly advantageous in the recovery of a crystallizable substance from solutions having a low purity of the substance. The solution from which the organic compound is recovered by the method of the invention is first brought to a sufficient supersaturation state to produce the nucleation. Typically, this is achieved by concentration and / or cooling. A preferred method of concentration is evaporation under subatmospheric pressure. The solution can be concentrated, for example, at a dry substance content of 75-98 percent by weight, - the preferred dry substance content depends on the solution to be treated and may be 82-95 weight percent, for example, the degree of supersaturation is maximized under the conditions obtainable within the viable viscosity limit. To produce crystals from a supersaturated solution, cooling is most often used, affecting the quality and predisposition to crystallization of the solution to be treated in time and cooling rate. In the nucleation step, the cooling speed of the supersaturated solution and the application of the working energy to the mixing process are linked in practice to prevent solidification of the crystallization mass and to limit the growth of the crystal to provide crystals generally in the range of no more than 10-100 microns, for example, while promoting additional nucleation of the crystallization mass. In general, a too high local cutting speed without effective intermixing can lead to solidification of the crystallization mass and should be avoided. At a given viscosity and feed power, the crystal size distribution is controlled by the cooling rate. The highest purity sources can be cooled more quickly, while sources with higher impurities or natural inhibitors may require a slower range. Prior to the initiation of cooling, finely milled seed crystals of the compound to be recovered are preferably added to the solution; the crystallization can, however, also be initiated by spontaneous seeding. The term "complete sowing" employed hereinafter in connection with sowing is commonly known in the art (see "Beet-Sugar Technology", 3rd Edition, edited by RA McGinnis (1982) pages 371-481) and calculate from the size of the seed crystals, the size of the crystal in the final finished product, and the production, as long as the number of crystals does not change. The solution that was brought to the state of supersaturation required by the nucleation, and the suspension formed by such a solution and the crystals contained therein, will also be called the crystallization mass in the following. The method of the invention is particularly advantageous and is representatively described in the recovery of xylose from solutions having a relatively low content of xylose in the dry substance, ie, approximately 30-50 weight percent in the dissolved dry substance. In that case, the separation processes involved in the processes of the prior art can be considerably diminished or totally eliminated, and the use of auxiliary solvents can also be eliminated, thus making the method essentially cheaper than the methods of separation. the prior art, and the xylose can be recovered in the form of a crystalline product from xylose solutions which are difficult to purify, for example, by chromatographic separation which, therefore, does not produce the purities of xylose that they are required in the crystallization methods of the prior art. In particular, the object of the invention is said method for the recovery of xylose from biomass hydrolysis products, which may also be fractions of xylose-containing by-product obtained in the wood processing industry, such as liquor. of sulfite cooking or a part thereof or a concentrate obtained therefrom, for example a concentrate produced chromatographically from the sulfite cooking liquor or a hydrolyzate pre-portion of the cooking liquor or a subsequent hydrolyzate or a filtration of ultrafiltration thereof. In the case that the solution to be treated is an aqueous solution of xylose (xylose purity of about 30-50 percent), in accordance with a preferred embodiment of the invention, the amount of seed crystals that are removed to use, it is high, at least 10 times compared to the full planting. In this way the supersaturation during crystallization is 1.4-3.0, preferably 1.5-2.5. The size of the crystal (length of the crystals) obtained is typically 10-100 micrometers. . A preferred way of carrying out crystallization according to the invention on xylose is to cool the crystallization mass of the seed at a relatively high rate, in a time of about 10-50 hours or less, to the supersaturation value required by a nucleation At present the temperature of the crystallization mass is typically 20-50 ° C, depending on the content of the dry substance of the crystallization mass, and the viscosity of the crystallization mass is in the range of 100-600 Pas. The suspension is stirred until a sufficient degree of crystallization has been reached (production, decrease in the purity of mother liquor xylose). For example, a crystallization vessel equipped with mixing paddles of 1.3-1.7 meters in length (from the shaft to the top) is typically used with raised cutting zones at a rotation speed initially of 3-6 revolutions per minute, and in the period of high viscosity of 0.5-3 revolutions per minute. The cutting speed is controlled in relation to the intermixing efficiency to avoid solidification of the crystallization mass while maintaining nucleation. Typically, the energy applied to the mixer is between approximately 100 W / cubic meters and approximately 800 W / cubic meters. Said range provides an effective mixing by means of which the nucleated material is transported to the interior of the crystallization mass. The period of precipitation of 1-4 days or until less, can reduce (convert to crystalline product) the level of xylose in the mother liquor to approximately 20 percent or less. After the same, the supersaturation of the crystallization mass decreases by increasing the temperature and / or diluting the crystallization mass with water or a solution containing xylose without a significant crystal solution until the viscosity of the crystallization mass has decreased to a sufficient degree for efficient separation of crystallized matter. A typical viscosity of the crystallization mass is 5-100 Pas after the decrease in viscosity. The crystals can be separated by filtration, decantation, centrifugation, etc., preferably by filtration. The mother liquor (ie, runoff) separated in this way, has been reduced to a very low content of xylose (as low as 16 percent in the dry substance). The xylose purity of the crystal fraction obtained is typically 60-90 percent on the dry substance, depending on the purity of the xylose in the crystallization mass and the execution of the process, and said fraction can be easily purified, if it is necessary, by means of normal crystallization techniques, for example. The purity of the fraction of the crystal obtained by the method of the invention can be improved by displacing a quantity of the mother liquor with a solvent or with air. It has not been possible to crystallize xylose from solutions having a purity of less than about 70 percent by the methods of the prior art without subjecting the solutions to difficult-to-handle purification treatments. The novel method developed can now achieve crystallization with xylose purities as low as about 30 percent on the dry substance. According to another preferred embodiment of the invention, sucrose can be crystallized from aqueous solutions thereof, such as from molasses obtained in the sugar industry. In this case, a small amount of glycerol (or some other organic solvent that may be present in the final molasses) can be added to the raw molasses before feeding it in the crystallization process. The solution thus obtained is evaporated under reduced pressure to a dry substance (DS) content of about 90-95 grams / 100 grams, and the crystallization mass obtained at about 80-90 ° C is transferred into a crystalizer. The crystallization mass is seeded with ground sucrose (average crystal size of 5 to 10 microns) at 70-90 ° C. The seed crystals are used in an amount that is up to 100 times compared to the case where the crystallization is based mainly on the growth of crystals. The amount of seed crystal is not very essential, since many new crystals are formed by nucleation during effective mixing. The crystallization is carried out in a crystallizer for approximately 10 days. The crystallization mass is cooled to about 50 ° C in 2-3 days and stirred at that temperature for about 7 days before the filtration preparations. The viscosity of the crystallization mass is less than 800 Pas at its highest point, and this decreases as crystallization proceeds. Prior to filtration, the viscosity of the crystallization mass is lowered by increasing the temperature by 5-15 ° C and / or optionally adding glycerol and / or water in an amount of up to about 10 weight percent. The crystal size obtained is typically about 10-50 microns.

The crystal fraction is preferably recovered by pressure filtration. The effective production of sucrose obtained after filtration in the experiments carried out so far has been about 30 percent of the sucrose contained in the starting molasses having a purity of sucrose of 40-60 percent based on the content of dry substance (DS). Production can be improved by further optimizing process conditions. The filtration to recover the crystalline product can be conveniently carried out with a pressure filter, for example, the Larox filter with 10-20 plates, using a fiber cloth of moderate porosity, separating at 2-16 bar and 0.5 to 1.0. hours of pressure time. The special embodiments of the method of the invention will be illustrated in more detail by means of the following examples, which are not intended as limiting the scope of the invention. . In some of the examples, the concentration of the crystallizable compound was increased by the addition of the pure compound to demonstrate the viability of the invention at different purities. The contents of the dry substance were determined by the Karl Fisher titration method (DS) or by the refractometric method (RDs).

Carbohydrates were analyzed by liquid chromatography (HPLC) using columns in which the ion exchange resin was in the Na + and Pb forms, or with PEDLC (ie, HPLC using an electrochemical pulse detector). The color was determined by the method of the International Commission for Uniform Methods of Sugar Analysis adapted [cf. Sugar Analysis; Official Methods and Attempts Recommended by the International Commission for Uniform Methods of Sugar Analysis (ICUMSA, for its acronym in English), ed. Schneider, F., ICUMSA, Peterborough, England, 1979, pages 125-128] at pH 5 (example of crystallization of xylose) and pH 7 (other examples) and by means of measuring from the filtered solution ( 0.45 micrometers) at 420 nanometers.

EXAMPLE 1 Crystallization of xylose 150 l of a xylose fraction obtained from a magnesium-based sulfite cooking liquor of beechwood was evaporated at sub-atmospheric pressure by chromatographic separation (substantially in accordance with the first step of the described process in U.S. Patent Number 4 631 129), which contained approximately 105 kilograms of dry substance and had a xylose purity of 39.9 percent, at about 60 ° C at a volume of about 80 liters. This xylose fraction was seeded at 58 ° C with 25 grams of milled xylose at a supersaturation value of 2.24, and the crystallization mass was transferred into a 100 liter crystallizer. The crystallization mass was subjected to linear cooling from 58 ° C to about 20 ° C with simultaneous stirring (viscosity 190 Pas measured with a Brookfield viscometer, type RVDV-I +) for approximately 25 hours, during which the supersaturation initially decreased to 1.66 in 3.7 hours, increasing after that to 1.93 (sowing time 20.9 hours, temperature 30.7 ° C) and then again decreasing gradually (at 20 ° C the supersaturation was about 1.70). The crystallization mass was further stirred at about 20 ° C. A pressure filter, Larox PF 0.1 H2, was used to separate the crystal fraction from the crystallization mass. The samples (at 20-200 grams) were taken from the crystallization mass at different times to separate the mother liquor, and stirring of the rest of the crystallization mass was continued. Before filtering the crystallization mass, its temperature was increased to approximately 30 ° C to decrease the viscosity. • 74.3 Hours after sowing, the viscosity of the sample of the crystallization mass was 66 Pas at approximately 30 ° C. The sample of the crystallization mass was filtered with the aforementioned Larox pressure filter, initially using a filtering pressure of 13 bar for 15 minutes, and after that a filtering pressure of 14.5 bar for five minutes. The glass cake obtained had a thickness of approximately 2.5 centimeters. The production of dry substance to the crystallization mass before filtration was 20.2 percent and the production of xylose was 50.4 percent. In Table 1 below, the results of the analyzes are shown, where the terms and abbreviations have the following meanings: Start = sample of the crystallization mass before cooling begins pH 5% = pH determined from the sample diluted with 5% water of RDs Cond. = conductivity determined from the sample diluted to 5% of RDs Cen. = ash content calculated from the conductivity by using the sucrose coefficient for sulfate ash Fil. = crystallization mass supplied to filter. The tests carried out showed that the production and the purity of the xylose were influenced by the agitation time of the crystallization mass in the nucleation zone (in this case, in a temperature range of approximately 20-30 ° C). The purity of the xylose from the fraction of filtered glass was 83.8 percent in the best case (time since sowing of 76.2 hours; the viscosity of the crystallization mass was 66 Pas at 29.8 ° C; filtration at 14.5 bar for five minutes), the purity of the filtrate xylose, that is, the runoff, was 18.1 percent at its lowest level (time since sowing 220 hours, the viscosity of the crystallization mass it was 59 Pas at 29.2 ° C, the filtration at 13-14 bar for fifteen minutes). The production of xylose in the crystals of the crystallization mass was 63.2 percent at its highest level (time since sowing of 49.3 hours).

Example 2 Crystallization of xylose Where not stated otherwise, the procedure was similar to that of Example 1. The solution containing xylose to be treated (20.5 kilograms) was obtained by combining a fraction of xylose obtained from a liquor of firing magnesium base sulfite of beech wood by chromatographic separation and an aqueous solution of a glass cake obtained from previous nucleation crystallization tests. The solution had a dry substance (DS) content of 62.7 percent and a purity of xylose of 53.0 percent. The solution was evaporated to a dry substance (DS) content of 89.7 percent. 13.4 kilograms of the crystallization mass obtained was transferred into a 10 liter crystallizer. Seed at 65 ° C with 5 grams of milled xylose (glass size 50 microns) at a supersaturation of 1.96, and linear cooling from 65 ° C to approximately 20 ° C for approximately 17 hours. During this time, the supersaturation decreased to 1.71, and remained in the range of 1.70-1.76 when the crystallization mass was stirred in the nucleation zone (at a temperature of 20-22 ° C). After 21.5 hours of the seeding (viscosity of 183 Pas at 22 ° C), the crystallization mass was heated to 32 ° C and filtered with a pressure filter (15 minutes, filtration pressure of 13.5 bar). The production of dry substance in crystals of the crystallization mass before filtration was 38.1 percent and the production of xylose, 72.1 percent. Table 2 below shows the results of the analyzes, in which the terms and abbreviations have the same meaning as in Example 1.

EXAMPLE 3 Betaine Crystallization The solution to be treated was a runoff obtained by the crystallization of betaine from the betaine fraction of the molar chromatographic separation (see Finnish Patent 77 845 mentioned above, international application WO 81/02420 ). The dry substance (DS) content of this solution was 63.4 grams / 100 grams, and the results of its analysis are shown in Table 3 below. 12.3 kilograms of this solution were evaporated under subatmospheric pressure in a rotary evaporator at a temperature in excess of 80 ° C at a dry substance content (DS) of 90.2 grams / 100 grams (Table 3 shows the results of the analysis). The linear cooling program of the concentrated solution obtained in this way was started in a 6-liter crystallizer from 95 ° C, the supersaturation of the solution being then 1.74. During complete crystallization, the crystallization mass was vigorously stirred. After 6.2 hours, the temperature was 76.5 ° C, the supersaturation was 3.18 and no crystallization took place. At that point, 0.6 grams of ground betaine monohydrate was added, and nucleation was initiated. The samples (at 20-200 grams) of the crystallization mass were taken at different times to separate the mother liquor, and the agitation of the crystallization mass was continued. Cooling was continued linearly at 30 ° C (time from sowing with betaine monohydrate of 31.1 hours), then the supersaturation of 2.43. The crystallization mass was stirred at this temperature for 3.8 hours, after which the temperature was raised to 35 ° C for 0.8 hours (then the viscosity was 113 Pas) and further to 37 ° C for 0.9 hours. At this point, the viscosity was 84 Pas, and the crystal fraction of the crystallization mass was separated with the Larox pressure filter of Example 1 using a filtration pressure of 14-15 bar for 30 minutes. A dry glass cake having a thickness of 8 millimeters was obtained. Table 3 below shows the results of the analysis in which the terms and abbreviations have the same meaning as in the previous examples, except that the color has been measured at a pH 7. On the other hand, the term "Solution "used in the first column refers to the solution of raw material before evaporation. The production of betaine to the crystal fraction was 37.7 percent of the betaine contained in the original solution, and the inositol production in the crystal fraction was 55.5 percent of the inositol contained in the solution.

The tests carried out showed that the production and purity of betaine and inositol were influenced by the agitation time of the crystallization mass in the nucleation zone. The purity of the betaine and inositol combined from the fraction of the filtered glass was 87.1 percent in the best case (the time since sowing was 37 hours). The purity of the betaine from the filtrate, ie the runoff, separated from the glass mass was 33. 3 percent at its lowest level and the purity of inositol was 7.0 (time since sowing 31 hours).

EXAMPLE 4 Crystallization of Betaine The solution to be treated was that of Example 3. 13.6 kilograms of this solution were evaporated under sub-atmospheric pressure on a rotary evaporator at a temperature slightly less than 80 ° C at a dry substance (DS) content of 97.6. grams / 100 grams. In this situation, planting was spontaneous, with the oversaturation of 3.69. Seven kilograms of the crystallization mass was transferred into a 6-liter crystallizer at 95 ° C, and 150 milliliters of water was added thereto at about 90 ° C. The crystallization mass prepared in this manner was cooled in a linear manner by vigorous stirring for 10 hours from 95 ° C to 70 ° C. The crystallization mass was stirred at this temperature for about nine hours (overnight), after which it was cooled for about nine hours at a constant temperature of 36 ° C, at which it was stirred for about 62 hours. The viscosity of the crystallization mass was 15.6 Pas at 70 ° C, 55 Pas at 45 ° C, and after stirring for 90 hours (from sowing) 347 Pas at 36 ° C. After the above stirring time, the temperature of the crystallization mass was first raised to 48 ° C (viscosity of 75 Pas), and after that the crystal fraction of the mass of crystallization was separated at 45 ° C (viscosity of 116 Pas, supersaturation of 17.87) with the Larox pressure filter of Example 1 using a filtration pressure of 14.5 bar for 20 minutes. A sufficiently dry glass cake having a thickness of 8 millimeters was obtained. The results of the analysis are shown in Table 4 below, in which the terms and abbreviations correspond to those of Example 3. The production of betaine to the crystal fraction was 47.0 percent of the betaine contained in the original solution, and the inositol production was 60.5 percent of the inositol contained in the solution. The purity of the combined betaine and inositol from the fraction of the filtered crystal was 77.3 percent at best, and the purity of the betaine from the runoff was 30.9 percent at its lowest point and the purity of the inositol it was 6.5 percent at its lowest point.

Example 5 Crystallization of xylitol The solution to be treated was a runoff obtained from the crystallization of xylitol. This was evaporated with a rotary evaporator at a pressure of 40 millibars at 70 ° C, up to a dry substance content (the RDs were determined by xylitol reading tables) of 93.8 grams / 100 grams. 12.3 kilograms of the obtained crystallization mass were transferred into a 10-liter crystallizer at a temperature of 50 ° C (s = 1.5), seeded with 10 grams of milled xylitol, and cooled to 25 ° C at 10 ° C. hours. Approximately three hours after the temperature of 25 ° C was reached, the crystallization mass had a viscosity of 61.5 Pas (s = 3.9). The crystallization mass was stirred at this temperature for a total of 8 hours, after which the temperature was further reduced (cooling water temperature 15 ° C). After about three hours, the crystallization mass had a temperature of 16 ° C (s = 4.9). The crystallization mass was stirred at this bath temperature for 18 hours, after which the viscosity was 250 Pas (s = 3.0) when the crystallization mass had a temperature of 18 ° C. Then the temperature of the crystallization mass was raised to 25 ° C in about three hours (then the viscosity was 81.5 Pas (s = 2.1)) and was further elevated to 28 ° C in about two hours. At that point, the crystallization mass had a viscosity of 59.5 Pas (s = 2.0), and the crystal fraction was separated from the crystallization mass with the Larox pressure filter of the previous examples, using a filtration pressure of 12 bar during 15 minutes. The compression was removed before an appropriate glass cake had formed. In Table 5, the results of the analysis are shown below, wherein the terms and abbreviations have the same meanings as in Example 3. The xylitol produced within the crystal fraction was 67 percent of the xylitol contained in the initial solution.

Example 6 Crystallization of sucrose The solution to be treated was obtained from molasses from a beet sugar factory. The solution was evaporated in a rotary evaporator to a dry substance content (the RDs were determined by the sucrose reading tables) of 90.3 grams / 100 grams. They were transferred into a 10 liter crystallizer, 14.5 kilograms of the crystallization mass obtained at a temperature of 62 ° C and plated with 10 grams of ground sucrose, and cooled with simultaneous vigorous stirring at 40 ° C in 40 ° C. hours. Approximately 25 hours after the temperature of 40 ° C was reached, the crystallization mass had a viscosity of 550. The temperature of the crystallization mass was raised to 53 ° C in about five hours, then the viscosity was 111 Pas. , and the crystal fraction was separated with a Larox pressure filter, using a filtration pressure of 12 bar for 15 minutes. The compression was removed before a sufficiently dry crystal fraction had formed. In Table 6, subsequently, the results of the analysis are shown, where the terms and abbreviations have the same meanings as in Example 3.

Example 7 Crystallization of xylitol The starting material was a runoff obtained from previous crystallizations of xylitol. This was filtered through a vacuum laboratory filter. The purity of the xylitol based on dry substance (RDs) in the obtained solution was increased to approximately 46 percent, by the addition of pure crystalline xylitol. The solution was evaporated with a vacuum laboratory evaporator, at a bath temperature of 60-70 ° C, for 6 hours to a dry substance content (RDs) of 94.1 grams / 100 grams. They were transferred to a 10 liter crystallizer, 13.58 kilograms (a volume of 10 liters) of the crystallization mass thus obtained, at a bath temperature of 50 ° C, and stirred for twenty minutes. At that time, the crystallization mass had a temperature of 51 ° C, and the supersaturation was 1.7. The crystallization mass was then seeded with 10 grams of milled xylitol, and subjected to linear cooling from 50 ° C to 23 ° C (cooling water temperature) in a lapse of 15 hours. At the end of this cooling period, the crystallization mass had a temperature of 24 ° C, a viscosity of 110 Pas, and a supersaturation of 3.2. The crystallization mass was further stirred at this temperature for about 2 hours, after which its temperature was lowered to 20 ° C for about 3 hours (then the viscosity was 200 Pas, supersaturation 3.5) and additionally 16 ° C for about 3 hours. Then the crystallization mass had a viscosity of 345 Pas. Agitation of the crystallization mass was continued at about this temperature (cooling water at a constant temperature of 15 ° C) for 42 hours. A sample taken after 17 hours of stirring at this temperature had a viscosity of 400 Pas and a supersaturation of 4.0. At the end of this period of agitation, the viscosity of the crystallization mass was 407 Pas. Then the temperature of the crystallization mass was raised to 20 ° C in half an hour (then the viscosity was 256 Pas) and further to 23 ° C in three hours. At that point, the crystallization mass had a viscosity of 198 Pas. At this point a sample of the crystallization mass was taken, and a runoff sample was separated therefrom by a laboratory centrifuge. The crystallization mass was then removed from the crystallizer, water was added in an amount of 5 weight percent of the crystallization mass, to decrease the viscosity, and the glass fraction was separated with the Larox pressure filter of the previous examples , using a filtration pressure of 15 bar for 30 minutes. In Table 7, subsequently, the results of the analysis are shown, where the terms and abbreviations have the same meanings as in Example 5.

The xylitol produced in the crystal cake during the Larox filtration was 57 percent of the xylitol contained in the initial solution.

Example 8 Crystallization of xylitol The same starting material as in Example 7 was used. The purity of the xylitol in the filtered solution was increased to about 47 percent by the addition of pure crystalline xylitol. The solution was evaporated with a rotary evaporator at a bath temperature of 70 ° C to a dry substance content (RDs) of 94.4 grams / 100 grams. They were transferred to a 10 liter crystallizer, 13.52 kilograms of the crystallization mass thus obtained. As in Example 7, the crystallization mass was effectively stirred throughout the process. The crystallization mass was seeded at a temperature of 56 ° C (s = 1.4) with 10 grams of ground xylitol, and subjected to linear cooling. In about 26 hours, the crystallization mass had reached a temperature of 20.5 ° C. The crystallization mass was stirred at this temperature for 42 hours, after which the supersaturation was 3.6. The viscosity of the crystallization mass at the end of this stirring period was 280 Pas.

Then, the temperature of the crystallization mass was raised to 25 ° C in about two hours (then the viscosity was 176 Pas; s = 3.1), and stirring was continued at this temperature for one hour. At this point a sample of the crystallization mass was taken, and a runoff sample was separated therefrom, by means of a laboratory centrifuge. Then part of the crystallization mass was removed from the crystallizer, and water was added thereto in an amount of 5 weight percent, to decrease the viscosity, which was 28 Pas after the addition of water. The crystal fraction of this part was separated with the Larox pressure filter of the previous examples, using a filtration pressure of 16 bar for 1 hour 15 minutes. Ethanol was added to the remainder of the crystallization mass in the crystallizer, in an amount of 5 weight percent of the crystallization mass, which was stirred at 25 ° C for about half an hour. The crystallization mass was then removed from the crystallizer and filtered in the same manner as described above for the first part of the crystallization mass. In Table 8, below, the results of the analysis are shown, whose terms and abbreviations have the same meanings as in Example 5. Filtration I refers to the Larox filtration with an addition of water, and Filtration II refers to the filtration. Larox with an addition of ethanol. The xylitol produced in the crystal cake from the primp > The filtration (with the addition of water) was 68 percent, and from the second filtration (with the addition of ethanol) 74 percent of the xylitol contained in the initial solution.

EXAMPLE 9 Crystallization of sucrose The raw material to be treated was molasses obtained from a sugar beet factory. The molasses was filtered and the filtrate was evaporated under reduced pressure to a dry substance content of Bx 93.0. They were transferred into a 100 liter crystallizer, 100 liters of the obtained crystallization mass, seeded with 100 grams of ground sucrose at 78.5 ° C, and cooled with simultaneous effective stirring at 50 ° C in about 60 hours. The viscosity of the crystallization mass was then 800 Pas, and stirring was continued, keeping the temperature substantially unchanged. Approximately 170 hours after the temperature of 50 ° C was reached, the crystallization mass had a viscosity of about 670 Pas. After 172 hours at about 50 ° C, the temperature of the crystallization mass was raised to about 60 ° C in about five hours, and after about 24 hours at this temperature, the crystallization mass had a viscosity of 241 Pas. The viscosity was further decreased by the addition of water (2 weight percent), and the crystal fraction was separated with a Larox pressure filter, using a filtration pressure of 16 bar for 60 minutes. The temperature of the food rose rapidly (filtration) Larox at 69 ° C just before filtration. In Table 9, below, the results of the analysis are shown, where the terms and abbreviations have the same meanings as in the previous examples, unless indicated otherwise.

EXAMPLE 10 Crystallization of sucrose The raw material to be treated was the same molasses as in Example 9, and this was initially treated as described in Example 9, except that some fraction of glycerol was added to the filtered solution. before evaporation. A glycerol fraction obtained from a chromatographic fractionation of vinasse was used for addition to the glycerol, and the amount of glycerol contained was 10 percent of the dry substance contained in the filtered solution. A 100 liter crystallizer was charged with the crystallization mass thus obtained (Bx 92.0), and the crystallization mass was seeded with 100 grams of ground sucrose at 76 ° C. The crystallization mass was cooled with simultaneous effective stirring to about 50 ° C in about 60 hours. Then the viscosity of the crystallization mass was about 210 Pas, and stirring was continued at this temperature for 11 hours. Then, the temperature was lowered to 46.5 ° C, whereby the viscosity was first increased to about 280 Pas and gradually decreased to about 220 Pas in 145 hours at this temperature. Then the temperature was gradually raised to 53 ° C (viscosity of 120 Pas), and after about 30 hours at this temperature, the glass fraction was separated with a Larox pressure filter, using a filtration pressure of 16.2 bar for 65 hours. minutes Table 10, below, shows the results of the analysis, where the terms and abbreviations have the same meanings as in the previous examples. The production of sucrose to the crystal cake during the Larox filtration was 35 percent from the sucrose of the original feed syrup.

EXAMPLE 11 Crystallization of sucrose The raw material to be treated was molasses obtained from a sugar cane factory. The molasses was evaporated under reduced pressure to a dry substance content of DS 88.1 (determined by the Karl-Fisher method). They were transferred to a 10 liter crystallizer, 12. 3 kilograms of the obtained crystallization mass were seeded with 10 grams of ground sucrose at approximately 75 ° C, and cooled with simultaneous effective stirring at 50 ° C in about 60 hours. The viscosity of the crystallization mass then was 860 Pas, and stirring was continued, keeping the temperature substantially unchanged. Eleven days after the temperature of 50 ° C, the crystallization mass had a viscosity of about 800 Pas, the first runoff sample was separated from the crystallization mass with a laboratory centrifuge, and 50 milliliters of water were mixed into the mass to reduce the viscosity. Four days after the addition of water, the crystallization mass had a viscosity of about 510 Pas and a temperature of 50 ° C, the second runoff sample was separated from the crystallization mass with a laboratory centrifuge, and 200 milliliters of water were mixed into the mass to reduce the viscosity. Four days after the addition of 200 milliliters of water, the viscosity was further decreased by raising the temperature of the crystallization mass to about 60 ° C in about 5 hours. After about one hour at this temperature, the crystallization mass had a viscosity of about 75 Pas, and a crystal fraction was separated with a Larox pressure filter, using a filtration pressure of 16 bar, for 60 minutes. The filtration speed was slow. The filter cloth was Tamfelt 71-2209-L1 with a pore size of approximately 17 microns. In Table 11, below, the results of the analysis are shown, where the terms and abbreviations have the same meanings as in the previous examples, unless indicated otherwise.

Example 12 Crystallization of sucrose The raw material to be treated was the same molasses as in Example 11, except that some sucrose was added before evaporation to raise the purity of the feed syrup to about 58 percent / DS. The syrup was evaporated under reduced pressure to a dry substance content of DS 89.7.

They were transferred to a 6 liter crystallizer, 8.4 kilograms of the obtained crystallization mass, seeded with 8 grams of ground sucrose at about 75 ° C, and cooled with simultaneous effective stirring at 50 ° C in about 60 hours. The viscosity of the crystallization mass was then about 900 Pas, and 60 milliliters of water were mixed into the mass to reduce the viscosity, and the stirring was continued, keeping the temperature substantially unchanged. Eight days after the temperature of 50 ° C was reached, the crystallization mass had a viscosity of about 720 Pas, the first runoff sample was separated from the crystallization mass with a laboratory centrifuge, and 50 milliliters of water inside the dough. Four days after the addition of water, the crystallization mass had a viscosity of about 610 Pas and a temperature of 50 ° C, and 1 kilogram of a 63 percent glycerol / water solution was mixed into the mass to reduce the viscosity. Five days after the addition of glycerol, viscosity of the crystallization mass was 17 Pas and the temperature was 50 ° C. After one day of mixing at this temperature, a crystal fraction was separated with a Larox pressure filter, using a filtration pressure of 16 bar, for 60 minutes. The filter cloth was the same as in Example 11. In Table 12, below, the results of the analysis are shown, where terms and abbreviations have the same meanings as in the previous examples, unless otherwise indicated. another way. The sucrose produced on the glass cake during the Larox filtration was about 45 percent from the sucrose in the feed syrup. The productions of the dry substance (expressed in percent weight / weight) given in the previous examples were calculated using the following formula: Production Production of compound;? S; X crystallizable dry substance Qristai where Qmasa is the purity of the mass of crystallization and Qrista? It is the purity of the crystal cake. In Table 13, below, the productions obtained in Examples 1-12 are summarized, as well as the purity of the feed, in each case, that is, the concentration of the compound to be recovered in the feed on the basis of of dry substance. In Table 13, total productions are calculated (ie, true) filtration from the purities of the crystallization mass, the filtration runoff, and the crystal cake, using the following formula: Production Qniasa'Qexcursion ^ total crystal of the = x x 100% f iltration wherein Qmasa and QCristal are as defined above, and Q is the purity of the filtration runoff. For example, the production of xylose in Example 1 is calculated, using the data in Table 1, as follows: Production 40.1-22.4 74.5 = x x 100% xylose 74.5-22.4 40.1 = 63.1% Effective filtration yields are calculated with a 100 percent crystal cake purity. This tells how much pure compound can be refined from the low purity crystal cake.

Table 1 Analysis of the crystallization of xylose Home Filtr. Glass Runner Cake Dry substance content (DS), g / 100 g 89.2 88.0 93.3 79.2 pH (solution 30-50%) 2.5 2.6 2.6 2.6 pH 5% 2.9 2.9 3.0 3.0 Cond. (from the solution that has 5% dry substances), mS / cm 2.22 2.20 1.16 2.64 Ash,% 3.99 3.96 2.08 4.39 Color, ICUMSA 000 15000 6800 19600 Carbohydrate content,% on the dry substance (DS) glucose 2.7 2.6 1.8 3.2 15 xylose 40.1 40.5 74.5 22.4 galact. + ramn. 3.7 3.8 1.8 4.6 arabinous 0 0 0 0 mañosa 3.6 0.7 0.3 4.5 Table 2 Analysis of the crystallization of xylose Home Filtr. Spice cake: im cristal Dry substance content (DS), g / 100 g 89.7 89.9 94.8 83. .7 pH 5% 3.1 3.1 3.2 3. .0 Cond. (from the solution that has 5% dry substances), mS / cm 2.22 2.22 1.23 3, .02 Ash,% 4.00 4.00 2.22 5. .44 Color, ICUMSA 13000 13400 700 20000 Carbohydrate content,% in dry substance (DS) glucose 2.2 2.3 1.2 3.1 xylose 52.5 52.8 78.0 29.2 galact. + ramn. 3.2 3.2 1.5 4.3 arabinosa 0 0 0 0 Handy 2.6 2.6 1.23 3.8 Table 3 Analysis of Betaine Crystallization Solution Home Filtr. Crystal Escurrim Cake 5 Dry substance content (DS), g / 100 g 63.4 90.2 91.9"91.1 89.8 pH (solution 30-50%) 9.9 10.0 10.0 10.0 10.0 pH 5% 9.8 9.8 9.8 9.6 9.7 Cond. (from the solution that has 5% dry substances), mS / cm 2.50 2.49 2.49 1.00 3.00 Ash,% 4 50 4.48 4.48 1.81 5.40 Color, ICUMSA 127500 139400 132500 42400 165000 Carbohydrate content, '15 in the dry substance (DS) raffinose 0.1 0.0 0.0 0.0 0.0 sucrose 1.8 1.8 1.8 0.7 2.2 other disaccharides 0.5 0.7 0.7 0.0 0.4 glucose 5.4 5.5 5.6 1.7 6.6 fructose 7.9 7.9 8.3 2.7 9.7 inositol 11.1 11.2 11.2 21.6 7.0 glycerol 8.1 8.3 8.8 3.5 9.7 betaine 46.8 47.4 47.3 65.5 40.5 Table 4 Analysis of the crystallization of betaine 5 Home Filtr. Glass Runner Cake Dry substance content (DS), g / 100 g 97.6 95.5 96.9 93.6 pH 5 9.9 9.9 9.7 9.9 10 Cond. (from the solution that has 5% dry substances), mS / cm 2.50 2.54 1.32 3.34 Ash,% 4.50 4.57 2.38 6.01 Color, ICUMSA 130000 135000 30900 183000 Carbohydrate content,% in the dry substance (DS) raffinose 0.0 0.0 0.0 0.0 sucrose 1.6 1.7 0.7 2.3 other disaccharides 0.4 0.0 0.0 0.6 glucose 5.8 6.2 2.3 8.2 fructose 7.6 9.3 3.6 11.6 inositol 10.4 11.6 17.1 6.5 glycerol 7.0 7.7 3.3 9.7 betaine 43.6 48.9 60.2 35.1 Table 5 Analysis of the crystallization of xylitol 5 Home Filtr. Crystal Runner Cake - Dry substance content (RDs), g / 100 g 93.8 92.9 92.5 17.22 > Carbohydrate content,% in the dry substance (RDs) monosaccharides 4.4 4.5 3.5 5.8 glycerol 4.0 4.1 3.4 4.8 mannitol 12.0 12.0 10.7 14.3 ramnitol 0.9 0.9 0.9 1.1 15 xylitol 38.0 38.1 44.12 29.7 sorbitol 8.5 7.6 7.8 9.8 others (substance not detected) 32.2 32.9 29.6 34.5 'The runoff sample was separated from the crystallization mass supplied to the filter, with a laboratory centrifuge (4500 rpm). 2) The sample was diluted with water, and the initial content of dried substance was not determined.

Table 6 Analysis of sucrose crystallization Home Filtr. Runoff Runoff2) Dry substance content 10 (RDs), g / 100 g 90.3 91.0 81.9 Carbohydrate content,% in the dry substance (RDs) raffinose 2.2 2.2 2.3 2.3 sucrose 60.0 57.8 55.1 54.0 15 betaine '5.6. 5.9 6.2 6.4 2) The runoff sample was separated by filtration, from the crystallization mass, with a laboratory centrifuge (4500 rpm).

Table 7 Analysis of the crystallization of xylitol 5 Final Filtr. Run-off cake ^ Crystal run-off Dry substance content (RDs), g / 100 g 93.9 89.4 94.3 77.7 10 Carbohydrate content,% in the dry substance IRDs) glycerol 5 5..11 4 4..22 2 2 .. 33 5 5..33 6.3 mannitol 1 100..88 1 100..22 5 5..55 1 144..44 16.8 15 ramnitol 0 0..99 0 0..99 0 0..44 1 1 .. 33 1.4 xylitol 4455..44 4466..33 7711..88 3300..44 23.1 sorbitol 77..Q0. 77..88 44..66 1100..22 11.6 others (monosaccharides and substance not detected) 30.8 30.6 15.1 38.4 42.2 20 Final = mass of crystallization at the end of crystallization 'Runoff of the pressure filter Larox 25' The sample of separate runoff from the crystallization mass with a laboratory centrifuge (4500 rpm).

Table 8 Analysis of the crystallization of xylitol Inic. Filtr. Runner Cake1) Runoff >; crystal Carbohydrate content,% in the dry substance (RDs) Filtration I Dry substance content (RDs), g / 100 g 94.0 89.9 94.2 82.4 10 glycerol 2.1 3.7 3.0 3.4 2.3 mannitol 8.7 9.4 4.3 13.4 15.1 ramnitol - 0.7 0.5 1.1 0.7 0.9 xylitol 49.5 46.7 75.2 28.4 22.9 sorbitol 5.2 7.4 10.1 10.4 10.6 15 others (monosaccharides and substance not detected) 33.8 12.3 6.3 43.7 48.2 Filtration II Dry substance content (RDs), g / 100 g 94.0 89.0 94.7 79.5 20 glycerol 2.1 3.3 - - mannitol 9.7 9.1 4.1 12.6 ramnitol 0.7 0.5 0.0 0.8 xylitol 49.5 45.2 74.5 24.9 sorbitol 5.2 7.2 3.5 9.5 25 others (monosaccharides and substance not detected) 32.8 34.7 17.9 52.2 * 'The run-off sample from the Larox 30 2> filter pressure filter. The runoff sample separated from the crystallization mass with a laboratory centrifuge (4500 rpm).

Table 9 Analysis of sucrose crystallization Startup Syrup Filtr. Run-off cake 'crystal feed Dry substance content Brix 77.0 92.7 90.8 93.6 Carbohydrate content,% in dry substance (RDs) raffinose 2.5 2.6 3.5 1.8 3.7 sucrose 60.9 61.5 61.0 70.8 52.9 betaine 5.2 5.3 5.4 3.2 5.8 20 The runoff sample was separated from the crystallization mass with a laboratory centrifuge (4500 rpm).

Table 10 Analysis of the crystallization of sucrose 5 Final Filtr. Runner cake1) Runoff) glass Dry substance content Brix 92.0 92.2 95.2 90.0 Carbohydrate content, 10% in the dry substance (RDs) raffinose 2.6 2.6 1.1 3.2 3.1 sucrose 54.8 52.2 80.5 46.7 44.1 glucose 2.8 2.8 1.9 3.2 - 3.2 15 fructose 0.6 0.5 0.9 0.5 0.6 inositol 0.4 0.3 0.1 0.3 0.4 glycerol "8.3 8.2 2.9 9.8 9.5 betaine 5.1 5.0 1.8 6.1 5.8 20 1) The runoff of the Larox 25 pressure filter 2) The runoff sample separated from the crystallization mass with a laboratory centrifuge (4500 rpm).

Table 11 Analysis of sucrose crystallization Home read Runoff) 2nd. Runoff1) Runoff) Dry substance content (DS), g / 100 g 88.1 39.63) 45.73) 25.73) Carbohydrate content,% on the dry substance (DS) raffinose 1.2 1.4 1.3 1.4 15 sucrose 43.0 36.0 38.8 41.4 glucose 3.6 2.2 2.2. 2.1 fruitful ^ The runoff sample separated from the crystallization mass with a laboratory centrifuge (4500 rpm). 2) The runoff of the Larox pressure filter 25) The dry substance is measured after the dilution of the sample.

Table 12 Analysis of sucrose crystallization Home Filtr. Drip Cake1) read. Runoff2) glass Dry substance content (DS), g / 100 g 89.7 86.3 45.5 3) 34.5 3) 47.9 3) 10 Carbohydrate content,% on the dry substance (DS) raffinose 1. .0 1. .1 0, .6 1.1 1.4 15 sucrose 57. .3 50. .2 66. .3 41.8 37.5 glucose 2. .7 1. .5 1. .0 1.9 2.3 fructose 6. .3 5, .3 3. .2 0.3 7.1 glycerol 0 11. .7 7. .2 13.4 0 20!) The run-off of the Larox pressure filter) The run-off sample separated from the crystallization mass with a laboratory centrifuge (4500 rpm) 25 3) The dry substance is measured after the dilution of the sample.

Table 13 Example Feed purity Total production Effective filtration filtration production 1 40% xylose 63-76% 57-67% 10 2 52.5% xylose 71% 63% 3 11.2% inositol 55% 40% 47.3% betaine 38% 24 % 4 10.4% inositol 60.5% 40% 43.6% betaine 47% 30% 5 38% xylitol 67% 31% 6 60% sucrose - 18% 15 7 45.4% xylitol 57% 47% 8 49.5% xylitol 68% 60% 9 61 % sucrose 52% 28% 10 55% sucrose 35% 28% 11 43% sucrose - 25% 20 12 57.3% sucrose 45% 29%

Claims (33)

1. A method for recovering a crystallizable organic compound from solutions containing the compound, characterized in that the compound is substantially crystallized by nucleation from a solution having high viscosity and high supersaturation with respect to the compound to be recovered, and the crystals formed are recovered.

2. A method as claimed in claim 1, characterized in that the solution is brought to a supersaturated state by evaporation, and a high viscosity is achieved by cooling.

3. A method as claimed in claim 2, characterized in that the cooling is performed for 10-100 hours.

4. A method as claimed in claim 3, characterized in that the cooling is performed in the temperature range of 95-20 ° C.

5. A method as claimed in any of claims 1-4, characterized in that nucleation is effected in a supersaturated solution having high viscosity, by effective agitation.

6. A method as claimed in any of claims 1-5, characterized in that to start the nucleation, the seed crystals of the compound to be recovered are added to the supersaturated solution, during evaporation or cooling.

7. A method as claimed in claim 6, characterized in that seeding crystals are used in an amount at least ten times higher in relation to the complete seeding.

8. A method as claimed in any of claims 1-7, characterized in that the viscosity of the suspension containing the supersaturated solution and the crystals of the compound to be recovered is reduced immediately before the recovery of the crietals.

9. A method as claimed in claim 8, characterized in that the viscosity is reduced by heating and / or dilution of the euspension.

10. A method as claimed in claim 8, characterized in that the viscoeity is reduced by diluting the suspension with a solvent, without significant dissolution of the crystals.

11. A method as claimed in claim 8, characterized in that the viscosity is reduced by means of mixing steam within the suspension.

12. A method as claimed in any of claims 1-11, characterized in that the crietals are recovered by filtration.

13. A method as claimed in claim 12, characterized in that the crystals are recovered by pressure filtration.

A method as claimed in any of claims 1-13, characterized in that the solution to be treated is an aqueous solution of the organic compound to be recovered.

15. A method as claimed in any of claims 1-14, characterized in that the organic compound q ^ e to be recovered is a sugar, a sugar alcohol or another polyol, or a sugar alcohol anhydride.

16. A method as claimed in any of claims 1-14, characterized in that the organic compound to be recovered is a carbohydrate, hydroxy acid or a salt of the miem, or an amino acid or salt thereof.

A method as claimed in claim 14 or claim 15, characterized in that the organic compound to be recovered has been selected from xylose, mannose, xylitol, mannitol, lactose, lactitol, sucrose, glucose, fructose , maltose, maltitol, isomaltose, isomaltuloea, lactuloea, aD-glycopyranosyl (1? 6) eorbitol, β-cyclodextrin, itaconic acid, citric acid, inositol, lactic acid, 1,4-anhydroglucitol, gluconates and glutamates.

18. A method as claimed in claim 17, characterized in that the organic compound to be recovered is xylose.

19. A method as claimed in claim 18, characterized in that the supersaturation of the solution with respect to the xylose, during crystallization, it is in the range of 1.4-4.0.

20. A method as claimed in claim 18 or claim 19, characterized in that the viscosity of the solution supersaturated during nucleation is in the range of from about 100 to about 1000 Pas.

21. A method as claimed in claim 20, characterized in that the viscosity of the suspension is reduced before recovery of the crystals, so that it is in the range of 5-100 Pas.

22 A method as claimed in claim 17, characterized in that the organic compound to be recovered is xylitol.

23. A method as claimed in claim 17, characterized in that the organic compound to be recovered is sucrose.

24. A method as claimed in any of claims 1-14, characterized in that the organic compound that is to be recovered is betaine.

25. A method as claimed in claim 18, 22, 23 or 24, characterized in that the supersaturation of the solution with respect to the substance to be recovered during crystallization is in excess of 1.3.

26. A method as claimed in claim 25, characterized in that the viscosity of the solution supersaturated during nucleation is in excess of 100 Pas.

27. A method as claimed in claim 26, characterized in that the viecosidad is reduced so that it has a value below 100 Pas, before the recovery of the crystals.

28. A method as claimed in any of claims 25-27, characterized in that the cooling time is less than 100 hours.

29. A method as claimed in any of claims 25-28, characterized in that the time of the start of separation of the crystal is less than 300 hours.

30. A method as claimed in any of claims 1-29, characterized in that the solution containing an organic compound is an aqueous solution derived from biomass, or a fermentation solution.

31. A method as claimed in claim 30, characterized in that the aqueous solution derived from biomass has been selected from molasses, vinasse, biomass hydrolyzate and parts thereof, and concentrates obtained therefrom.

32. A method as claimed in any of claims 1-31, characterized in that the separate runoff in the recovery of the crystals is used to prepare a new supersaturated solution for crystallization, based predominantly on nucleation.

33. A method as claimed in any of claims 1-32, characterized in that the obtained crietals are recrystallized, by repeating said method, or in a manner known per se.