WO2015047097A1

WO2015047097A1 - Sugar recovery from sugar beets

Info

Publication number: WO2015047097A1
Application number: PCT/NL2014/050668
Authority: WO
Inventors: Ronald Peter Wilhelmus Kesselmans; Paulus Johannes Petrus De Lange
Original assignee: Bouwcoach Engineering B.V.
Priority date: 2013-09-30
Filing date: 2014-09-30
Publication date: 2015-04-02

Abstract

The invention is directed to a process for recovering sugar from sugar beets and/or for conserving sugar beets or fragments thereof. The process comprises the steps of preparing a mixture comprising sugar beet fragments and alcohol; and storing said mixture.

Description

Title: Sugar recovery from sugar beets

The invention is directed to a process for recovering sugar from sugar beets, a process for conserving sugar beets and a mixture that can be obtained by these processes.

The sugar beet (Beta Vulgaris Altissima) is an important source of sugar for many countries. Sugar beets typically comprise more than 15 wt.% sugar, of which over 90 wt.% is sucrose. Such high amounts of sugar are required for an efficient production of sugar from the beets. Sugar beets having a sugar content less than 15% are typically found unsuitable for efficient sugar production. Furthermore, sugar beets contain high amounts of water. Sugar beets may contain more than 65 wt.% water (typically even more than 75 wt.%) up to about 85 wt.%. Sugar beets are typically sowed in spring and harvested in autumns, typically from September onwards.

Sugar beets have the disadvantage that they are ill conserved after harvesting them. In particular, the sugar content of sugar beets decreases after harvesting. This is mainly due to biological mechanism like rotting, which may depend on temperature.

As a result of the decreasing sugar content after harvesting, the current commercial production of sugar from sugar beets is based on processing the sugar beets shortly after harvesting them in a period of only several months each year. The harvest and processing of the sugar beet is referred to as "the campaign", reflecting the organization required to deliver the crop at a steady rate to processing factories that run 24 hours a day for the duration of the harvest and processing.

Although it is a known technique to conserve sugar beets by drying (typically after fragmenting the sugar beets), such conservation is not sufficient to store the sugar beets for longer periods of time without loosing its sugar content. For example, US 2,943,004 describes a process wherein sugar source material is first dehydrated to 10% moisture or less and subsequently, but is subsequently immediately extracted with alcohol at temperatures above 75 °C.

Accordingly, the main problem of the production process of sugar from sugar beets remains that it can be conducted only during a relatively small period of the year ("the campaign"), viz. in a period up to only several months after the harvest of the sugar beets. As a result, the processing installations of the existing industry are in production only for a relative small period of the year, which makes the process capitally intensive.

A further disadvantage of the known production process is that it is energetically intensive. In the current process, the sugar beet is generally treated as a whole. The sugar beets are first cut after which sugar is extracted from the resulting fragments or pulp. However, this has the disadvantage that the process uses relatively a lot of energy, because the sugar needs to be soaked off the sugar beet pulp. In order to accomplish this, sugar is typically extracted at relatively high temperature (about 70 degrees Celsius) from the pulp. Further, water originating from the sugar beets (and any additional water that may be added during the process) needs to be evaporated at the end of the process consumes energy.

A further disadvantage of the current process is that certain undesirable byproducts are formed. In particular, the production of the byproduct molasses is economically unfavorable.

A further disadvantage of the current process is that additives need to be added during the production process to safeguard the sugar quality, for example calcium oxide (quicklime) and/or carbonic acid

(dissolved CO2). However, these additives do not add value to the end product. In fact, addition of such additives can lead to environmental issues resulting in the need for additional measures to solve these issues.

Accordingly, it is an object of the present invention to solve at least one of the above problems of the existing production process of sugar from sugar beets. In particular, it is an object of the invention to provide a production process with which sugar can be produced from sugar beets throughout the entire year. A further object is to provide a production process that has a relatively low energy consumption, while at the same time having a high yield. Finally, an object of the invention is to increase the shelf life of sugar beet and sugar beet material.

The inventors found that at least one of the objects above was met by providing a method comprising the steps of preparing a mixture comprising sugar beet fragments and alcohol and storing said mixture.

The method of the invention may be used for recovering sugar from sugar beets and/or for conserving sugar beets. The inventors

surprisingly found that during storage of the mixture of sugar beet fragments and alcohol, the sugar content of the mixture is not reduced. Apparently, the sugar reducing processes normally encountered in sugar beet (fragments) can be essentially avoided by storing the fragments in alcohol, even when only a relatively little amount is used. The sugar content in the mixture remained high even when storing the mixture for a

significant amount of time.

The inventors further found that an additional advantage of the process of the invention is that during storage sugar and water are efficiently extracted from the sugar beet fragments. The storage step (which may also referred to herein as the extraction step) thus results in a mixture of sugar beet fragments and a sugar containing liquid. This mixture may also be referred to herein as the product mixture. Surprisingly, no elevated temperatures or additives were found to be required for an efficient extraction.

Thus, the invention provides a method for simultaneously conserving sugar beets and extracting sugar from sugar beets.

During storage/extraction there is a partial exchange between alcohol and the water and sugar from the sugar beet fragments. At least part of the alcohol is taken up by the sugar beet fragments, while water and sugar are extracted from the sugar beet fragments. This results in a mixture of sugar beet fragments and a sugar containing liquid. The sugar beet fragments are depleted in sugar and water and comprise the alcohol. The sugar beet fragments obtained after storage/extraction may therefore also be referred to as the 'dehydrated', 'depleted' or simply as the 'treated' sugar beet fragments.

In order to isolate the sugar from the product mixture, the sugar containing liquid may be first separated from the treated sugar beet fragments. The sugar can then be obtained from the sugar containing hquid using different processing steps, e.g. by evaporation or crystallization.

Thus, the process of the invention makes it possible to recover sugar from sugar beet fragments long after the sugar beets have been harvested. When kept in alcohol, the sugar content of the mixture will not significantly decrease or at least much slower than in untreated sugar beets. Thus, using the process of the invention, it is no longer necessary to produce sugar from sugar beets in the above-described "campaigns". Accordingly, the production installations for obtaining sugar from sugar beets can be in production throughout the whole year. The process of the invention even provides for a modular production process, wherein the sugar beet

fragments can be stored on different locations than where they are to be further processed (decentralized).

It is further surprising that by storing sugar beet fragments in alcohol not only is the sugar being conserved, but the sugar also migrates out of the sugar beet fragments. This has the obvious advantage to no difficult and/or energy consuming process steps need to be conducted to extract the sugar from the sugar beats. Without wishing to be bound by any theory, it is expected that migration occurs via an osmoses mechanism from the sugar beet fragments into the alcoholic solution. Furthermore, the yield of the process of the invention is surprisingly high and therefore commercial viable. On top of that the sugar is produced without the need for any additives and can be conducted at relatively low energy consumption. No elevated temperatures are required for the process. In fact, temperature does not even seem to have a large affect on the yield of the sugar obtained.

The invention thus relates to both extend the shelf life of the sugar beet (i.e. to conserve the sugar content in the sugar beet after harvesting) and to extract sugar from the sugar beets using alcohol. To achieve these objects, it is necessary to fragment (e.g. cut, mill, or crush) the sugar beets into smaller fragments and subsequently mix them with an alcohol. The amount of alcohol to supply to both protect and extract as described above may depend on several factors, such as the water/alcohol ratio of the total mixture, the size of the sugar beet fragments and whether the mixture is mixed during storage. Surprisingly the temperature seems to only have a minor effect on this process and on the yield. Also, it was noticed that the sugar beets could colour during the process, but that such colouring did not seem to have any effect on the yield or quality of the obtained sugar.

After the storage period, the duration of which is dependent on the market demand in combination with the sugar content in the liquid, the liquid is physically separated from the sugar beet fragments. Subsequently, the alcohol is evaporated from the mixture. The alcohol can be reused in the process. The sugar may be isolated by crystallization or as a syrup. This may be done using techniques known in the art, such as crystallization or evaporation. Prior to isolation, the mixture may be decolourized. The scale of these processes is flexible.

The process of the invention will be described in more detail below.

The sugar beets may first be washed in order to remove e.g. soil.

Thereafter, the sugar beets may be fragmented. The fragments thus obtained are herein referred to as sugar beet fragments, which are solid pieces of sugar beet, which pieces hold (amongst others) water and sugar. Fragmentation provides for the alcohol being able to conserve the sugar beet and to make it possible for the sugar containing aqueous substance in the sugar beets to migrate out of the beet. Fragmenting may be conducted by techniques known in the art. For example, the sugar beet fragments may be obtained by slicing, pressing, shredding, cutting or milling (e.g. via rotating mills) the sugar beets. Use may be made of e.g. drums, knife mills, high shear mills, pulp mills or cutting machines.

Further, some sugar beet juice may be released during fragmentation. Such juice is no longer held by the fragments as a result of the fragmentation. The amount in which such juice is released depends on the fragmentation technique used. Since the juice will also contain sugar, the juice is typically not separated from the fragments. Accordingly, juice formed in the fragmentation step is typically mixed with the alcohol and sugar beet fragments when preparing the mixture in the next step. With respect to preparing the mixture with alcohol (especially with respect to amounts and ratios), the juice may be considered as part of the sugar beet fragments.

The size and shape of the sugar beet fragments may vary. The shape of the fragments can be cubes, slices, strips or pulp. The size of the fragments may be determined by its thickness or height (with the length and width of the fragment being larger than the thickness). On the one hand, small sugar beet fragments provide for a large contact surface of the fragments with alcohol, which promotes extraction and/or migration.

Therefore, the thickness of the sugar beet fragments is preferably 5 cm or less, preferably 2 cm or less, more preferably 1 cm or less, even more preferably 0.5 cm or less, e.g. 0.1-0.5 cm. On the other hand, small sugar beet fragments are more difficult to separate from the liquid after storage. Accordingly, it may not be necessary nor desirable to fragment the beets to a fine pulp (which may also be very energy consuming). Accordingly, the skilled person will be able to choose a suitable size and shape taking into account the desired extraction speed of the fragments, energy consumption associated with fragmentation and the separation of the fragments and the fluid.

The sugar beet fragments typically have about the same composition as the sugar beets they are derived from (as defined above for the sugar beet). Normally, the fragments have a water content of least 50 wt.%, typically 65-85 wt.%. Further, they may comprise 10-25 wt.% sugar, preferably at least 15 wt.% sugar (e.g. 15-20 wt.% sucrose). Although an even higher sugar content may be desirable in view of the extraction step, the sugar content is in practice limited to the maximum amount of sugar that can be observed in sugar beets, which is about 25 wt.%. The solid components of the sugar beet fragments mainly (>75wt.%) consist of cellulose, hemicellulose, lignin, and pectin.

Subsequently, a mixture of the sugar beet fragments and alcohol is prepared. This mixture can be prepared by mixing the sugar beet fragments and alcohol, e.g. by adding an alcohol to the sugar beet

fragments. It is not required to dry the fragments before preparing the mixture. The amount of alcohol in the mixture can vary from 1 to 100%, calculated based on the total weight of water in the mixture (i.e. including the water present in the sugar beet fragments). Preferably, alcohol is added to the sugar beet fragments in an amount of 2.5-50 wt.%, more preferably 5- 20 wt.%, based on the total amount of water in the final mixture.

The alcohol may be added as part of an alcoholic liquid, which is an alcohol containing liquid that may further comprise one or more other components, for example water. The alcoholic liquid is preferably a mixture of water and alcohol. Preferably, the alcoholic liquid comprises at least 50 wt.% alcohol, more preferably at least 65 wt.% alcohol. The amount of alcohol that is added to the sugar beet fragments by adding the alcoholic liquid may be 0.1- 100 wt.%, preferably 1-75 wt. %, more preferably 2.5-50 wt.%, most preferably 5-20 wt.% of the total weight of water present in alcohol containing liquid and in the sugar beet fragments (which water typically makes up the total weight of water present in the mixture).

The alcohol used may be methanol, ethanol, propanol or isopropanol. More preferably, methanol or ethanol is used and most preferably ethanol. The alcohol may be added to the sugar beet fragments as a mixture of water and alcohol.

In view of energy conservation, the sugar beets, fragments thereof and the alcohol are typically not heated during preparation of the mixture. Accordingly, the mixture is typically prepared at a temperature below 70 °C, preferably below 50 °C, even more preferably below 30 °C.

The mixture of the sugar beet fragments and alcohol may be prepared such that the weight ratio between the total amount of water and the total amount of alcohol present in the mixture (water: alcohol) will be at least 1:10, preferably at least 1:5, more preferably at least 1: 1, even more preferably at least 1:0.2, or even at least 1:0.1. Furthermore, the mixture may be prepared such that the weight ratio between the total amount of water and the total amount of alcohol present in the mixture may be at most 1000: 1, preferably at most 100: 1, more preferably at most 40: 1, or even at most 20: 1. Accordingly, the water/alcohol ratio in the mixture is generally between 1: 10 and 1000: 1 and in a preferred embodiment between 1: 1 and 40: 1. In view of the typical amounts of water present in sugar beets, this means that the final mixture will have a preferred alcohol content of about 2-45 wt.% (more preferably 3-30 wt.%), based on the total weight of the mixture.

Further, the mixture of the sugar beet fragments and alcohol may be prepared such that the weight ratio between the amount of sugar beet fragments and the amount of alcohol in the mixture (beet:alcohol) may be between 1: 1 and 50: 1, preferably between 6: 1 and 30: 1.

In a preferred embodiment, the mixture of the sugar beet fragments and alcohol is prepared such that the amount of alcohol in the mixture is 0.1- 100 wt.%, preferably 1-75 wt.%, more preferably 2.5-50 wt.%, most preferably 5-20 wt.% of the total weight of water in the mixture.

After the mixture of sugar beet fragments and alcohol has been prepared, the mixture is stored.

The mixture of the sugar beet fragments and alcohol may be stored during a time period ranging from 1 day to 2 years. In view of the sugar extraction that occurs during storage, the storage time may also be referred to as the extraction time. Preferably the storage time is 1 week to 1.5 years. As mentioned above, it is no longer necessary to recover sugar from the sugar beets shortly after harvesting. Accordingly, the storage time may be at least one week, at least 50 days, at least 100 days or at least 6 months. Storage can be conducted using technologies known in the art. The mixture is typically stored in a container, e.g. in a barrels, basin, or pipes. Storage may be conducted at large scale. For example, the mixture may comprise at least 1000 kg of sugar beet fragments. Furthermore, the mixture may be stored in the dark, e.g. in a sealed container. As also described below, the mixture may be mixed, e.g. stirred, turned, or by separating the alcoholic liquid from the container and spraying it onto the mixture, etc. The temperature of mixture during storage is not particularly critical. In view of energy conservation, the mixture is typically not heated or cooled. Accordingly, the mixture is typically stored at a temperature below 70 °C, preferably below 50 °C, even more preferably below 30 °C.

The mixture may be mixed during storage. By mixing the fragments and the alcohol, most surfaces of the sugar beet fragments are regularly brought into contact with the alcohol, which may promote the yield of sugar extraction. Mixing is especially desirable when relatively low amounts of alcohol are used. Mixing can be conducted by techniques known in the art, for example by (slowly) rotating the mixture or (slow) stirring. The mixture may also be mixed by pumping liquid from the mixture from the bottom part of the storage container and contacting it with the top part of the mixture.

As also described above, by storing the mixture of alcohol and sugar beet fragments sufficiently long, the sugar is extracted from the fragments. Thus, the storage step results in a mixture comprising a sugar containing liquid (which may further contain water and alcohol) and treated sugar beet fragments (which are dehydrated and depleted in sugar).

The water content in the sugar beet fragments is typically reduced to less than 25 wt.% after storage. The total weight of the dehydrated sugar beet fragments may be less than 25% of their original weight, for example 5-15 %. The sugar containing liquid typically contains more than 25 wt.% water (e.g. 15-98 wt% water), less than 75 wt.% of alcohol (e.g. 85 - 2 wt.% of water), and at least 0.1 wt.% sugar (e.g. 0.1 - 15 wt.% of water). More in particular, the sugar containing liquid may contain more than 50 wt.% water (e.g. 51-98 gew.%), less than 50 wt.% alcohol (e.g. 1-48 wt.%) and at least 0.1 wt.% sugar (e.g. 1-20 wt.%).

The sugar containing liquid can be further processed to recover the sugar. Accordingly, the process of the invention may further comprise the step of isolating the sugar from the mixture obtained after storage. The step of isolating the sugar from the sugar containing liquid may be conducted in various ways.

Typically, the sugar containing liquid is first separated from the treated sugar beet fragments. Any suitable separation technique may be used, for example decanting and filtration. Furthermore, filter presses, centrifugation, flotation, sedimentation, cyclones, etc. may be used and also technologies and installations like pressing with the use of drums, spiral filter presses, and other industrial known presses.

The treated sugar beet fragments may be treated a second time with alcohol or even multiple times (e.g. up to 10 treatments). In this case, the steps of preparing the mixture (adding alcohol) and storing the mixture as described above are conducted one or more additional times using the treated sugar beet fragments remaining after the last storage step. Such multiple treatment of the sugar beet fragments may be conducted batchwise or in a continuous set-up. Of course, whether a second or further treatment is viable depends on the remaining sugar content in the fragments and whether it is economically feasible to perform a second extraction.

Furthermore, the amount of alcohol and water that is added to the fragments may need to be adapted for the second and further extraction steps, in particular in such a way that there is sufficient liquid to separate from the sugar beet fragments. As the amount of water will decrease with each step (the fragments are dehydrated), this will generally result in an alcohol/water ratio that is relatively high compared with the first extraction step. In order to compensate for this, additional water may be added when preparing the second or further mixture.

The extraction step (or even the entire process of the invention) can be conducted batch wise, semi-continuous or continuous.

The sugar containing liquid obtained after storage mainly consists of dissolved sugar, water and alcohol. The sugar may be isolated from the sugar containing liquid, for example by evaporation or crystallization. Such isolation processes are known in the art and the skilled person will know how to recover sugar from sugar containing liquids. The sugar containing liquid is typically subjected to a concentration step, wherein the alcohol and optionally also part of the water present in the liquid are evaporated (either together or in separate steps). Such a concentration step may be conducted at high temperatures (e.g. above 75 °C or above 95 °C) and/or reduced pressure.

Alcohol may be removed from the sugar containing liquid by evaporation (typically by distillation). Distillation techniques known in the art may be used, e.g. under normal or reduced pressure, for example using column distillation. The recovered alcohol can be reused in the process, e.g. as conservation and extraction liquid.

If the sugar is intended to be isolated as a syrup, liquid (water and, if still present, alcohol) can be evaporated from the sugar containing liquid to the required levels of the syrup. Optionally, the mixture may be discolored (e.g. using a carbon filter) before evaporation.

If the sugar is intended to be isolated as crystalline sugar, sugar is obtained from the sugar containing liquid by crystallization. In this case, alcohol is typically first removed from the sugar containing liquid. Sugar can be crystallized from aqueous sugar solutions using known technologies and even in existing sugar production installations based on process steps like concentrating the sugar with heat, a crystallization step, and cooling. After separation of the sugar crystals from the so-called mother liquor, the obtained sugar may be subjected to centrifugation, sieving, decanting and/or drying. The sugar can then be sold in the required shape. The remaining mother liquor may be recycled in the crystallization process. The very low level of impurities of the mother liquor compared to the existing and known production process makes this possible. In case of the recycling of the mother liquor it is obvious that a purge to prevent increased levels of impurities is required in the process for the crystallization of sugar. The purge and/or the mother liquor can be used for example for the production of ethanol or together with the low sugar containing remaining sugar beet fragments at the end of the process be used as described below.

The depleted sugar beet fragments obtained in the process can be used in different applications. Preferably, the alcohol present in the sugar beet fragments obtained in the separation step is recovered and may be reused by feeding it to the sugar beet fragments. Because of the low concentration of water in the depleted sugar beet fragments, they may be used as an energy source (e.g. fuel), optionally after further drying. If the remaining sugar content in the fragments is high enough the fragments can be used for the production of ethanol {e.g. by fermentation and/or digestion), potentially in combination with enzymes that are able to convert cell walls into ethanol. Another application for the sugar beet fragments could be as source for methane which can be used for the production of electricity using known technologies like anaerobic digestion. Also possible is the use of these fragments as a energy source for the production of hydrogen. Other applications for the sugar beet fragments with low sugar content can be as fertilizer, cattle feed, etc.

In another aspect, the invention is directed to a mixture comprising sugar beet fragments and a sugar containing liquid. Such a mixture can be obtained by the process of the invention, i.e. the product mixture obtained after storage.

The mixture of the invention may comprise at least 80 wt.%, preferably at least 90 wt.% of sugar containing liquid. Further, the mixture may comprise at least 1 wt.%, typically at least 2 wt.% solid biomass. The biomass originates from beet root and is present in the mixture in solid form (typically as part of the sugar beet fragments). The biomass generally comprises cellulose, hemicellulose, hgnin, and pectin. These four compounds may form the majority (over 75 wt.%) of the solid biomass present in the mixture.

The sugar containing liquid comprises or essentially consists of water, alcohol and sugar. The liquid typically comprises at least 0.1 wt.% sugar, preferably at least 5 wt.%, more preferably at least 10 wt.% sugar. The sugar may in particular be sucrose.

The liquid further comprises water and alcohol. The sugar containing liquid typically comprises at least 15 wt.% water, 0.1 to 85 wt.% alcohol and 1-20 wt.% sugar. Preferably, the liquid comprises at least 50 wt.% water, 0.1 to 49 wt.% alcohol and 1-20 wt.% sugar, more preferably 60- 92 wt.% water, 5-20 wt.% sugar, and 3-35 wt.% alcohol. The sugar beet fragments in the product mixture of the invention are dehydrated. Accordingly, the fragments may comprise less than 50 wt.% preferably less than 25 wt.%, more preferably less than 10 wt.% water.

The mixture comprises substantially no quicklime and/or (dissolved) carbon dioxide.

In another aspect, the invention is directed to a storage container, for example a silo, comprising at least 1000 kg of the mixture of the invention (as described above).

The invention will be illustrated by the following experimental examples.

Example 1:

164 g sugar beets containing 18% sugar (29,5 gram) were cut into cubes of 1 x 1 cm. Subsequently 55 gram ethanol (100%) was added. The mixture was shaken and stored in the dark at room temperature (20 degrees Celsius). After 160 days the liquid was separated from the beet fragments by decantation.

A. The solution was evaporated under reduced pressure. The weight of the light yellow syrup was measured (7.1 gram) and the sugar content was measured using a refractometer. The sugar content was 91%. The total amount of recovered sugar was 6.5 gram.

B. To the remaining sugar beet fragments 55 gram ethanol (100%) was added. The mixture was shaken and stored in the dark at room temperature (20 degree Celsius). After 30 days the liquid was separated from the beet fragments by decantation. The solution was evaporated under reduced pressure. The weight of the light yellow syrup was measured (11.9 gram) and the sugar content was measured using a refractometer. The sugar content was 86%. The total amount of recovered sugar of the second (B batch) was 10.2 gram. C. To the remaining sugar beet fragments of the second extraction (B) 55 gram ethanol (100%) was added. The mixture was shaken and stored in the dark at room temperature (20 degree Celsius). After 25 days the liquid was separated from the beet fragments by decantation. The solution was evaporated under reduced pressure. The weight of the light yellow syrup was measured (6.5 gram) and the sugar content was measured using a refractometer. The sugar content was 92%. The total amount of recovered sugar of the third (C batch) was 6.0 gram.

In total 22.7 gram of sugar was extracted and concentrated leading to a recovery yield of 22.7/29.5 x 100% = 77%

Example 2:

134 g sugar beets containing 18% sugar (24.2 gram) were shredded for 30 seconds in a Moulinette. Subsequently 5 gram ethanol (100%) was added. The mixture was shaken and stored into the dark at 4 degree Celsius. After 190 days the liquid was separated from the beet fragments by decantation.

A. The solution was evaporated under reduced pressure. The weight of the light yellow syrup was measured (17.9 gram) and the sugar content was measured using a refractometer. The sugar content was 85%. The total amount of recovered sugar was 15.2 gram.

B. To the remaining sugar beet fragments 5 gram ethanol (100%) was added. The mixture was shaken and stored into the dark at 4 degree Celsius. After 25 days the liquid was separated from the beet fragments by decantation. The solution was evaporated under reduced pressure. The weight of the light yellow syrup was measured (3.6 gram) and the sugar content was measured using a refractometer. The sugar content was 80%. The total amount of recovered sugar of the second (B batch) was 2.6 gram. In total 18.1 gram of sugar was extracted and concentrated leading to a recovery yield of 18.1/24.2 x 100% = 75%

Example 3:

142 g sugar beets containing 18% sugar (25,5 gram) were shredded for 30 seconds in a Moulinette. Subsequently 10.2 gram ethanol (100%) was added. The mixture was shaken and stored into the dark at room temperature (20 degree Celsius). After 190 days the liquid was separated from the beet fragments by decantation.

A. The solution was evaporated under reduced pressure. The weight of the light yellow syrup was measured (19.2 gram) and the sugar content was measured using a refractometer. The sugar content was 85%. The total amount of recovered sugar was 16.3 gram.

B. To the remaining sugar beet fragments 10.2 gram ethanol (100%) was added. The mixture was shaken and stored into the dark at room temperature (20 degree Celsius). After 25 days the liquid was separated from the beet fragments by decantation. The solution was evaporated under reduced pressure. The weight of the light yellow syrup was measured (5.0 gram) and the sugar content was measured using a refractometer. The sugar content was 84%. The total amount of recovered sugar of the second (B batch) was 4.2 gram.

C. To the remaining sugar beet fragments of the second extraction (B) 10.2 gram ethanol (100%) was added. The mixture was shaken and stored into the dark at room temperature (20 degree Celsius). After 82 days the liquid was separated from the beet fragments by

decantation. The solution was evaporated under reduced pressure. The weight of the light yellow syrup was measured (3.2 gram) and the sugar content was measured using a refractometer. The sugar content was 78%. The total amount of recovered sugar of the third (C batch) was 2.5 gram. In total 23.0 gram of sugar was extracted and concentrated leading to a recovery yield of 23.0/25.5 x 100% = 94%.

Example 4:

10 times 100 g of Sugar beets (19.7 % sugar) were shredded for 30 seconds in a Moulinette blender to pulp. The crushed sugar beet material was collected in a container and 150 g 96% ethanol was added. The experiment started on November 15th 2013. The mixture was stored in the dark at room temperature (20 degree Celsius) and shaken once a week. The results are shown in Table 1, which shows the extraction yield over time.

On regular periods shown in the table in column B in days (Column C is cumulative in days), the ethanolic liquid was decanted from the sugar beet fragments using a paper filter. The weight of the filtrate was measured in grams (Column D) and the same amount of 96% ethanol was added to the sugar beet fragments in the above mentioned container. The container was stored again at room temperature (20 degree Celsius) and was again shaken once a week.

The filtrate was evaporated under reduced pressure resulting in light yellow syrup. The mass of this syrup was determined (column E) and the sugar content measured using a refractometer. The degrees of Brix were recalculated to 100% sugar and shown in column F. The total isolated sugar for each step was measured and shown in column G and the total isolated sugar of the steps combined is shown in column H. The total yield of the sugar obtained in the combined steps was calculated based on the total sugar present in the initial mixture (197.2 grams) and is shown in column I. After 283 days, 79.4% of the available sugar was successfully isolated. The results of this Example are further shown in the graph in Figure 1.

Example 5:

160 g sugar beets containing 19% sugar (38 gram) were shredded for 30 seconds in a Moulinette. Subsequently 30 gram ethanol (96%) was added. The mixture was shaken and stored into the dark at room

temperature (20 degree Celsius). The mixture was shaken weekly. After 160 days the mixture was pressed in a manual fruit press. The liquid was collected.

Subsequently the liquid was evaporated under reduced pressure. The weight of the light yellow syrup was measured (26.0 gram) and the sugar content was measured using a refractometer. The sugar content was 86%. The total amount of recovered sugar was 22.6 gram leading to a yield of 57%.

Example 6:

160 g sugar beets containing 19% sugar (38 gram) were sliced into chips with a thickness between 0.01 and 0.2 cm. Subsequently 30 gram ethanol (96%) was added. The mixture was shaken and stored into the dark at room temperature (20 degree Celsius). After 160 days the mixture was presses in a manual fruit press. The liquid was collected.

Subsequently the liquid was evaporated under reduced pressure. The weight of the light yellow syrup was measured (36.9 gram) and the sugar content was measured using a refractometer. The sugar content was 86%. The total amount of recovered sugar was 31.7 gram leading to a yield of 81%.

Claims

1. A process for recovering sugar from sugar beets comprising the steps of

- preparing a mixture comprising sugar beet fragments and alcohol; and

- extracting sugar from the sugar beet fragments by storing the mixture for at least one week to obtain a mixture comprising a sugar containing liquid and treated sugar beet fragments; and

2. A process for simultaneously preserving sugar beets and extracting sugar from sugar beets, comprising the steps of

- fragmenting sugar beets into fragments; and

- preparing a mixture of the sugar beet fragments and alcohol;

- storing said mixture for at least one week.

3. A process according to claim 1 or 2, further comprising the step of separating the sugar containing liquid from the treated sugar beet fragments.

4. A process according to any of the previous claims, further comprising the step of isolating sugar from the sugar containing liquid.

5. A process according to claim 4, wherein sugar isolation includes the step of evaporating alcohol and optionally water from the sugar containing liquid.

6. A process according to any of the previous claims, wherein the mixture is prepared by fragmenting sugar beets and subsequently mixing the resulting sugar beet fragments with alcohol, wherein the sugar beet fragments have a water content of at least 50 wt.%.

7. A process according to any of the previous claims, wherein the sugar beet fragments have a water content of 65-85 wt.%.

8. A process according to any of the previous claims, wherein the preparation and storage steps are conducted at a temperature of less than 70 ° C, preferably less than 50 ° C, more preferably less than 30 ° C.

9. A process according to any one of the previous claims, wherein the weight ratio between the total amount of water and the total amount of alcohol present in the mixture is between 1: 10 and 1000: 1, preferably between 1:5 and 100: 1, more preferably between 1: 1 and 40: 1, even more preferably between 10: 1 and 40: 1.

10. A process according to any one of the previous claims, wherein the amount of alcohol in the mixture is 0.1-100 wt.%, preferably 1-75 wt.%, more preferably 2.5-50 wt.%, most preferably 5 -20 wt.% of alcohol, based on the total weight of water in the mixture.

11. A process according to any one of the previous claims, wherein the sugar beet fragments in the mixture are stored for at least 50 days or for at least 100 days.

12. A process according to any one of the previous claims, wherein the alcohol is methanol or ethanol.

13. A process according to any one of the previous claims, wherein the mixture comprises at least 1000 kg of sugar beets.

14. A process according to any one of the previous claims, wherein the sugar beet fragments are obtained by cutting or milling sugar beets.

15. A process according to any one of the previous claims, wherein the sugar beet fragments have a thickness of 5 cm or less, preferably 2 cm or less, more preferably 1 cm or less, even more preferably 0.5 cm or less.

16. A process according to any one of claims 3-14, wherein the sugar beet fragments obtained in the separation step are mixed with alcohol and the mixture thus obtained is stored for at least one week.

17. A process according to any one of claims 3-15, wherein the alcohol present in the sugar beet fragments obtained in the separation step is recovered and reused by feeding it to the sugar beet fragments.

18. A process according to any one of claims 1 and 3-15, wherein the sugar beet fragments obtained in the separation step are used as fuel.

19. A process according to any one of the previous claims, wherein the mixture comprises substantially no calcium oxide and/or carbon dioxide.

20. A process according to any one of the previous claims, wherein the process is a batch process, a semi-continuous or a continuous process.

21. Mixture comprising sugar beet fragments and a sugar containing liquid comprising water, alcohol and sugar.

22. A mixture according to claim 21 comprising sugar beet fragments and a sugar containing liquid, which liquid comprises at least 15 wt.% water, 0.1 to 85 wt.% alcohol and 1-20 wt.% sugar.

23. A mixture according to claim 21 or 22, wherein the sugar containing liquid comprises 60-92 wt.% water, 5-20 wt.% sugar, and 3-35 wt.% alcohol.

24. Mixture according to any one of claims 21-23, wherein the sugar- containing liquid comprises at least 0.1 wt.%, preferably at least 5 wt.%, more preferably at least 10 wt.% sucrose.

25. Mixture according to any one of claims 21-24, wherein the mixture comprises at least 2 wt.% solid biomass originating from sugar beets.

26. Mixture according to any one of claims 21-25, wherein the sugar beet fragments contain less than 50 wt.% preferably less than 25 wt.%, more preferably less than 10 wt.% water.

27. Mixture according to any one of claims 21-26, wherein the mixture comprises substantially no lime and / or carbon dioxide.

28. Mixture according to any one of claims 21-27, obtainable by the process according to any one of claims 1-20.

29. Storage container, for example a silo, comprising at least 1000 kg of the mixture according to any one of claims 21-28.