JPH06122892A - Production of crude wax - Google Patents

Abstract

PURPOSE:To efficiently produce crude wax using a solid residue separated from squeezed juice of cane as a raw material. CONSTITUTION:This producing method is characterized by consisting of the following steps (I) to (III). (I) An extraction step for mixing a solid residue with a hydrophobic organic solvent for extraction and extracting a wax content with the solvent, (II) a separating step for adding water to the mixture obtained in the previous step (II), stirring the mixture, allowing the mixture to stand and separating the mixture into a solvent layer in which wax content is dissolved and a water layer containing a solid content and (III) a solvent recovering process for collecting the solvent layer and separating and recovering the crude wax and the solvent.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a crude wax from sugar cane.

[0002]

2. Description of the Related Art The sugar content in sugar cane is mainly the cane.
It is contained in the sap inside. Therefore, when sugar is produced from sugar cane, the sap is squeezed out by pressing the sugarcane stalk, and the juice is boiled to obtain crude sugar. Various squeezing machines, such as a sugar mill, are used for squeezing the sugarcane stem. Since the obtained juice contains a wax component, a resin component, etc., a coagulant, a filter aid, etc. are added to this if necessary, and the wax component and the resin component are filtered. Crude sugar is produced from this filtrate, and a wax component and a resin component are produced from the filtration residue (filter cake, generally called “kachacha”). The filtration residue contains crushed stalks, vascular bundles, stalk pulp, precipitants, mud, etc.
It is an apparently solid substance containing 0 to 80% by weight.

The stem of sugar cane contains a wax component in addition to the sugar component, and this wax component remains in the filter cake as described above. Conventionally, filter cakes have only been used for compost and the like, and effective utilization thereof has been desired. As a method of producing wax from the filter cake, for example, a method of extracting using a water-soluble solvent can be considered. According to this method, extraction is easy even if a large amount of water is present in the filter cake,
It is difficult to separate the solvent from the extraction residue, the solvent and water, and the wastewater treatment.

As another extraction method, since the solvent extraction is impeded by the coexistence of water, the filter cake is previously dried to reduce the water content to a certain value or less, and then the ordinary extraction such as soybean oil extraction is carried out. Similarly to the above, a method of extracting the wax component using an organic solvent can be considered. In this method, an ordinary extraction method can be adopted, but the utility cost becomes excessive because a large amount of water in the filter cake needs to be evaporated and dried. In addition, in order to increase the extraction efficiency, a pretreatment step is required in order to make the shapes of the dried filter cake uniform, and further, the extraction solvent is likely to remain in the filter cake, so that there are drawbacks such as a decrease in extraction efficiency. is there.

In addition, if water is further added to the filter cake so that the water content is 85% by weight or more (usually 90% by weight or more), the filter cake becomes fluid and should be treated as a fluid in appearance. Therefore, a method in which a large amount of water is added in advance for extraction can be considered. According to this method, since it can be performed in the same manner as the liquid-liquid extraction, the operation is easy, and for example, OJ Swen
An extraction tower can be utilized that is an improvement on the rotating disk type extraction tower described in Son et al., U.S. Pat. No. 2,499,008. However, this method has several drawbacks, for example, the volume of the extraction column becomes excessive due to the addition of so much water that it becomes fluid. In order to improve the contact efficiency between the extraction solvent and the fluid filter cake, contact between the solid content in the filter cake and the solvent becomes a problem, and therefore vigorous stirring is required. Further, if the volume fraction of the solvent is not a certain value or more, uniform stirring cannot be performed, and the amount of the solvent used becomes excessive. That is, the volume of the extraction equipment becomes large. Furthermore, when vigorous stirring is performed, the amount of solvent attached to the liquid filter cake increases, and there is a risk that the extraction efficiency will rather decrease. In addition, in the case of vigorous stirring, there are many problems such as the generation of emulsion and the miniaturization of solid content, which makes it difficult to carry out the filtration operation which is a subsequent step.

[0006]

In view of the above circumstances, it is an object of the present invention to provide a method for efficiently producing a crude wax using a solid residue separated from sugar cane juice as a raw material. .

[0007]

That is, the first aspect of the present invention is to provide a method for producing a crude wax, which comprises the following steps (I) to (III): (I) Extraction step: a step of mixing the solid residue separated from the sugar cane juice and a hydrophobic organic solvent for extraction, and extracting the wax component contained in the solid residue with the organic solvent, (II) separation step: extraction Water is added to the mixture of the solid residue and the organic solvent that has undergone the step, the mixture is left standing after stirring, and the step of separating the solvent layer in which the wax component is dissolved and the aqueous layer containing the solid component, and (III) the solvent Collection step: a step of collecting a solvent layer in which a wax component is dissolved and separating and collecting the crude wax and the solvent from the solvent layer. The second aspect of the present invention is to provide the following steps (Ia) to (II
The invention provides a method for producing a crude wax, which is characterized by comprising I). (Ia) Deaeration step: a step of substantially deaerating air contained in the solid residue by stirring the solid residue separated from the sugar cane juice while heating, (I) Extraction step: deaeration A step of mixing the vaporized solid residue with a hydrophobic organic solvent for extraction and extracting the wax component contained in the solid residue with the organic solvent, (II) separation step: the solid residue and the organic solvent that have undergone the extraction step Water is added to the mixture of, and the mixture is stirred and then allowed to stand to separate into a solvent layer in which a wax content is dissolved and an aqueous layer containing a solid content, and (III) a solvent recovery step: the wax content is dissolved A step of separating the solvent layer and separating and collecting the crude wax and the solvent from the solvent layer.

The present invention will be described in detail below. When producing sugar from sugar cane, first, the stem of sugar cane is squeezed by squeezing it with various squeezing machines, for example, roll squeezing such as a sugar mill. Sugar cane may be pulverized in advance. The juice obtained contains sugar,
It is an opaque liquid because it contains wax and resin.
Wax components and resin components are removed from this squeezed juice to separate a liquid containing sugar, which is appropriately boiled to be crystallized to obtain crude sugar. In order to remove wax and the like from the above juice, if necessary, a flocculant or a filter aid such as slaked lime is added in an amount of 2 to 10% by weight (usually about 5% by weight) to cause aggregation.
The solid component is filtered off by an appropriate method such as a filter press. A large amount of wax and resin is contained in the squeeze remaining as a residue on the filter press, that is, the filter cake (Kachasha). Wax and the like can be removed by ultrafiltration or centrifugation in addition to the filter press.

In the present invention, the solid residue separated from the squeezed juice of sugar cane is not limited to filter press after the above squeezed juice is optionally added with a coagulant or the like, and an appropriate method such as ultrafiltration or centrifugation is used. Refers to the residue obtained by separation by. As mentioned above, the solid residue usually contains, in addition to wax and resin, crushed stalk hull, vascular bundle, stalk pulp and coagulant, filter aid, precipitant, mud, etc. Further, it is an apparently solid substance which usually contains 70 to 80% by weight of water.

In the deaeration step of the present invention, the solid residue separated from the sugar cane juice is heated by an appropriate method, for example, a method of blowing steam, and at the same time stirred, the air contained in the solid residue is heated. To substantially degas.
In addition, this process is arbitrarily performed as a preferable embodiment. That is, as will be described later, the degassing step increases safety against fire, improves extraction efficiency, and preheats, but it is not always necessary depending on the type of solid residue used, water content, etc. No need.

The stirring in the deaeration step can be performed by a cylindrical or groove type stirring / heating transfer machine of screw, ribbon or paddle type. In order to break up the solid residue, which is partially in the form of lumps, into fine pieces, the agitator as described above, which is capable of simultaneously applying shearing force, is preferable. This form is also effective in terms of degassing effect. Further, in order to carry out continuous operation, it is preferable to use an agitator having a transfer function.

In the degassing step, by substantially degassing the air contained in the solid residue, it is possible to prevent the air from being mixed into the subsequent step using the organic solvent, and thus to the fire. The safety is increased, and the problem that the extraction solvent hardly penetrates into the solid residue due to the presence of air is solved, and the extraction efficiency is improved. The determination of whether or not the removal of air has been achieved is appropriately made by the specific gravity of the solid residue or visually.

In the degassing step, heating is performed at the same time as stirring, and the solid residue of the raw material is preheated to a temperature required in the next extraction step. This heating is also effective for removing air. The heating temperature can be appropriately determined according to the extraction temperature, and is usually in the range of 70 to 120 ° C.

If the handling property (transportability) is insufficient due to the large amount of solids in the solid residue, a suitable amount of the solid residue may be added before the degassing process or the extraction process described below. Water can also be added to enhance transportability. But,
If a large amount of water is added in advance for slurrying,
As described above, a large amount of water will coexist during the solvent extraction, the amount of the extraction solvent used will increase, the extractor volume will increase, and the wax extraction efficiency will also decrease, which is preferable. Absent. For this reason, the amount of water should be kept to the minimum necessary even when water is added to improve the transportability when supplying the solid residue to the extraction process. Specifically, the amount of water in the solid residue is 80% by weight or less.

In the extraction step, the solid residue separated from the squeezed sugar cane itself is treated, or after the solid residue is treated in the degassing step, the hydrophobic organic solvent is mixed and stirred to remove the wax content from the solid residue. Extract. As the extraction solvent, a hydrophobic organic solvent is used in order to dissolve the wax content in the solid residue. A hydrophilic organic solvent such as alcohol or ketone is not preferable because it is not easy to separate it from the water contained in a large amount in the solid residue. The hydrophobic organic solvent used for extraction is not particularly limited as long as it is a hydrocarbon solvent, but from the viewpoint of environmental pollution, safety, etc., for example, paraffins or naphthenes, etc., non-aromatic in the range of C _{5 to} C _9. Group hydrocarbon solvents, preferably C _{5 to} C ₉ liquid saturated hydrocarbons, such as paraffinic hydrocarbons, especially C
Isoparaffins ₆ -C _9, like normal paraffin or mixtures of these C ₅ -C _8.

The amount of the above-mentioned organic solvent blended is 0.
It is from 05 to 10 times by volume, preferably from 0.1 to 1.5 times by volume. When the amount of the solvent is less than 0.05 volume times of the solid residue, the extraction becomes insufficient, while when it exceeds 10 volume times, the efficiency of the solvent recovery in the latter stage is deteriorated, which is not preferable. The extraction temperature varies depending on the solvent, but is not particularly limited as long as it is not higher than the boiling point of the solvent under operating pressure,
For example, a temperature range of 70 to 150 ° C. is used.

As a concrete extraction method, the solid residue and the above hydrophobic organic solvent are kneaded and extracted. As the stirrer used here, similarly to the stirrer used in the degassing step, a cylindrical or groove type, for example, screw, ribbon or paddle type stirring and heating transfer machine can be used. Similar to the degassing step, a stirring method capable of simultaneously applying a shearing force is preferable in order to break up the solid residue partially having a lump into pieces. Further, in order to perform continuous operation, it is preferable that the agitator has a transfer function.

The extraction time is 1 to 60 minutes, preferably 5 to
It takes about 30 minutes. The pressure may be normal pressure, but can be appropriately increased by self pressure or by injecting an inert gas. When applying pressure, the extraction time can be shortened. The pressure applied is usually 5 kg / cm ² or less, though it depends on the pressure resistance of the equipment. In addition, as the solvent to be used or a part thereof, it is possible to use the solvent recovered from the later solvent recovery step.

In the next separation step, water is added to the mixture of the solid residue obtained in the extraction step and the solvent, the mixture is stirred, and then allowed to stand to separate the solvent layer. In this process,
It is important to add water so that the solid content / water weight ratio is below a specific value. That is, in the mixture from the extraction step, the solid residue and the solvent are usually apparently uniformly mixed, and the hydrophobic organic solvent layer is not always clearly separated. Therefore, as it is, it is difficult to separate the solvent layer in which the wax component is dissolved. However, when water is added such that the solid content / water weight ratio is a certain value or less, for example, 1/7 or less, preferably 1/9 or less, the solvent layer in which the wax content is dissolved becomes the upper layer, and solids such as plant fibers are solidified. The water layer containing the components becomes the lower layer and is clearly separated, and the solvent layer is easily separated. The lower limit of the solid content / water weight ratio is not particularly limited, but if it is too small, a large amount of water will be added,
It is uneconomical because the volume of the extractor and the separator must be increased. From this point of view, the lower limit is 1
It is about / 100. As described above, since the solid residue has a solid content / water weight ratio of about 1/3, for example, if twice the amount of water contained in the solid residue is further added,
The weight ratio of water is 1/9, and the separation is excellent. Water is added so that the weight ratio is satisfied, stirring is carried out if necessary, and the mixture is allowed to stand to separate the solvent layer in which the wax component is dissolved and the aqueous layer containing the solid component. The stationary time for separation is appropriately selected, but is usually about 5 to 60 minutes.

After the stationary separation, in the solvent recovery step,
The solvent layer in which the wax component is dissolved is recovered, and the crude wax and the solvent are separated from the solvent layer and recovered. For this purpose, an appropriate conventional method can be adopted. For example, the solvent layer can be heated and concentrated to evaporate the solvent to recover it, and the crude wax can be recovered as a residue. In addition, a method such as cryogenic separation or precipitation separation by adding a polar solvent can be adopted. Usually, the separation of crude wax by heat concentration is the simplest. Separation in this process
The recovered crude wax can be used as a wax material for various purposes as it is or after further purification by an appropriate ordinary method. On the other hand, the recovered solvent can be appropriately circulated and reused as an extraction solvent in the extraction step.

Since the aqueous layer containing the solid content separated in the separation step is a mixture of the solid content such as plant fibers in sugar cane and water, it can be used as it is as a compost, for example. However, it is preferable to add a water recovery step to the above series of steps to recover the aqueous layer and further separate the solid content and water. In the step, an appropriate method can be adopted for separating solid content. For example,
A centrifugal settler such as a decanter and a filter such as an Oliver filter can be used. The water recovered from the process can be appropriately circulated and reused as the water to be added in the separation process. The water remaining in the solid content is
The amount of the recovered solid content is adjusted to an appropriate amount depending on the intended use.
Usually, water is separated so as to be 80% by weight or less in consideration of transportation and the like. Incidentally, since the solvent separation is usually almost completely performed in the solvent recovery step,
It is not necessary to further remove the solvent in the water recovery process,
If necessary, a solvent separation step such as steam stripping can be added before the step.

[0022]

EXAMPLES The present invention will be described in more detail below with reference to examples. <Examples 1 to 4> The sap is squeezed from the sugar cane stem by roll pressing using a sugar mill, and about 5% by weight of slaked lime is added to the squeezed juice as a slaked lime liquid to coagulate wax components and the like, and then the same agglomeration. The product was filtered by a filter press to obtain a filter cake (Kachatha) as a residue. A predetermined amount of the obtained filter cake (containing 25% by weight of solid content) was put into an autoclave equipped with anchor type stirring blades, steam was blown into the autoclave at a rotation speed of 200 to 400 rpm while stirring and heated to 80 to 100 ° C. . By the above operation, the air occluded in the filter cake was removed and the filter cake was preheated. After degassing was finished, the normal paraffin isoparaffinic solvents or C ₇ of C ₆ -C ₉ added as an organic solvent for the wax extracted was heated to a predetermined extraction temperature. The stirring was performed for a predetermined time, and the wax component was extracted from the filter cake. Next, the entire mixture was transferred to a separator, a predetermined amount of warm water was added, the mixture was stirred for several minutes, and allowed to stand. By leaving it for a predetermined time,
The mixture was separated into an aqueous layer containing fibers and the like in the lower layer and an upper solvent layer in which the wax component was dissolved. The solvent layer was extracted from the separator, placed in a rotary evaporator heated to 80 ° C. in a water bath, and the solvent was evaporated under reduced pressure to recover the wax. The operating conditions and results are shown in Table 1.

<Comparative Examples 1 and 2> To the filter cake separated from the squeezed sugar cane juice in Example 1, the amount of water shown in Table 1 was added in advance to form a slurry. Then, this was put into an extractor, and the solvent described in Table 1 was added to perform extraction. After the extraction, the wax was transferred to a separator and statically separated, and the solvent was removed from the solvent layer obtained by the separation by distillation to recover the wax. The extractor, the separator, and the like appropriately used have a volume corresponding to the amount of the solvent used. The operating conditions and results are shown in Table 1.

Comparative Example 3 In Example 1, water 190
The operation was performed in exactly the same manner except that g was not added. Therefore, the water added in this example is only the condensed water of the steam initially blown in the degassing step. The operating conditions and results are shown in Table 1.

[0025]

[Table 1]

In Comparative Examples 1 and 2, water was added to the filter cake in advance to make it slurry to give fluidity, and as a result, the solid contents were 7% by weight and 11% by weight, respectively. . The separation of the solvent layer and the aqueous layer was relatively easy, but in the case of Comparative Example 2, the fluidity was poor and the wax recovery rate was low. In Comparative Example 3, water was not added after degassing the filter cake, but the separation of the solvent layer after extraction was poor and the wax recovery rate was low. Examples 1 and 2 differ in the amount of water added in the extraction. In Example 2 in which the amount of water was increased, the solvent layer and the water layer were completely separated, and the volume of the solvent layer after separation was larger than the volume of the added solvent because the wax content was dissolved. There is. Example 3 is an experiment in which the amount of solvent is reduced as compared with Example 2, and Example 4 is an experiment in which the type of solvent is changed, and all show good results.

[0027]

The effects of the method of the present invention are as follows. (1) The solid residue separated from the sugar cane juice can be used as a raw material as it is. (2) Both extraction efficiency and separation efficiency were improved by making extraction and separation into independent steps. (3) In the extraction step, the contact efficiency between the solid residue and the extraction solvent is good, and extraction under pressure is possible, so the extraction time can be shortened. (4) Due to the synergistic effect of the above (2) and (3), the amount of extraction solvent used can be reduced. (5) Since the solvent layer and the water layer are efficiently separated in the separation step, the standing time for separation can be shortened. (6) Due to the synergistic effect of the above (3) to (5), the volume of the stationary separation tank can be reduced.

Claims (2)

[Claims] 1. A method for producing a crude wax, which comprises the following steps (I) to (III). (I) Extraction step: a step of mixing the solid residue separated from the sugar cane juice and a hydrophobic organic solvent for extraction, and extracting the wax component contained in the solid residue with the organic solvent, (II) separation Process: a process of adding water to the mixture of the solid residue and the organic solvent that has undergone the extraction process, stirring and standing still, and separating into a solvent layer in which the wax component is dissolved and an aqueous layer containing the solid component, and ( III) Solvent recovery step: a step of separating the solvent layer in which the wax component is dissolved and separating and recovering the crude wax and the solvent from the solvent layer. 2. A method for producing a crude wax, which comprises the following steps (Ia) to (III). (Ia) Deaeration step: a step of substantially deaerating air contained in the solid residue by stirring the solid residue separated from the sugar cane juice while heating, (I) Extraction step: deaeration A step of mixing the vaporized solid residue with a hydrophobic organic solvent for extraction and extracting the wax component contained in the solid residue with the organic solvent, (II) separation step: the solid residue and the organic solvent that have undergone the extraction step Water is added to the mixture of, and the mixture is stirred and then allowed to stand to separate into a solvent layer in which a wax content is dissolved and an aqueous layer containing a solid content, and (III) a solvent recovery step: the wax content is dissolved A step of separating the solvent layer and separating and collecting the crude wax and the solvent from the solvent layer.