CH707151A2 - The process of industrial transformation of green rye. - Google Patents

Abstract

The present invention relates to an industrial process for processing green rye to extract cellulose fibers that can be used in particular in the preparation of paper pulp, the manufacture of nonwoven products, the production of plant supports for above-ground crops or the like. Green rye is first subjected to wet silage preliminary treatment and the solid material called "cake" is separated from a suspension called "juice" from a mass of ensiled material. In particular, a suspension is produced by adding to said cake an aqueous solution of a base and mixing said suspension to neutralize the acids and give it a basic pH. The aqueous solution of a base is dosed in such a way that the basic pH of the suspension produced is between 7 and 12 and preferably between 8 and 9. The base is chosen from the following compounds: sodium hydroxide (NaOH), calcium oxide (CaO), potassium hydroxide (KOH), calcium carbonate Ca (OH) 2.

Description

Technical area

The present invention relates to a process for the industrial processing of green rye to extract cellulose fibers used in particular in the preparation of paper pulp, the manufacture of nonwoven products, the production of plant supports for crops above ground, the production of panels of thermally insulating material or the like.

Prior art

[0002] Paper making techniques based on various fibers derived from vegetable substances are known. One of the problems is the supply of raw materials and the cost of these raw materials. It is the same for other applications such as the manufacture of nonwoven textiles. Plant supports for growing above ground in horticulture were long made of rock wool and more and more frequently, we use the coconut fiber. The problem of supply is that of transporting these materials and the carbon tax related to this long-distance transport for European users, for example.

[0003] There is a definite interest in the recovery of considered plant materials which are little used. Green rye is an intercrop crop that is primarily used for the protection of agricultural land. In the European Union and in other countries, planting this type of crop is now mandated and subsidized. Since the use of green rye for livestock feed is limited because of the high content of cellulose, this product provides an opportunity for industrial applications.

Presentation of the invention

The present invention provides a process of industrial processing of green rye which allows to obtain quality products, at extremely competitive prices, this transformation consisting in extracting on the one hand fibers whose industrial applications are multiple and on the other hand, the nutritive components that can also be used in the composition of many industrial products.

This object is achieved by the process according to the invention as defined in the preamble and characterized in that, during a preparatory phase, a preliminary treatment of green rye is carried out by silage in a humid medium and in a confined atmosphere, in which an separation of the solid material called "cake" and a suspension called "juice" is carried out during an intermediate phase from a mass of ensiled material and that, during a final phase, the cellulose fibers are extracted separately by treatment of the cake and extraction of the dry matter by treatment of the juice.

To effect the separation of said cake of said juice, during said intermediate phase from said mass of ensiled material, is preferably used a screw press.

To extract the cellulose fibers by treatment of the cake during said final phase, a caustic treatment is advantageously carried out to neutralize the acids and impart to said cake a basic pH, by adding thereto, an aqueous solution of a base and the cake is stirred during the treatment to produce a fluid suspension.

Said aqueous solution of said base is advantageously dosed in such a way that the basic pH of said suspension is between 7 and 12, and preferably greater than 11.

The temperature of said solution is between 30 ° C and 90 ° C and preferably greater than 50 ° C.

Said base is preferably chosen from the following compounds: sodium hydroxide (NaOH), calcium oxide (CaO), potassium hydroxide (KOH), calcium carbonate Ca (OH) 2 sodium hydroxide (NaOH), sulphite of sodium (Na2S), sodium bicarbonate (Na2CO3), sodium sulfate (Na2SO4), calcium oxide (CaO), potassium hydroxide (KOH), calcium carbonate Ca (OH) 2 or mixtures thereof.

According to an advantageous embodiment, the aqueous solution of sodium hydroxide (NaOH) contains between 0.5 and 5% NaOH and preferably between 1.0% and 2.5 NaOH.

According to another advantageous embodiment, the aqueous solution of calcium oxide (CaO) contains between 0.5 and 5% of CaO and preferably between 1.5% and 4% of CaO.

To extract the cellulose fibers by processing the cake, it performs mechanical grinding and mixing operations.

To enhance the said juice, it is preferably carried out a treatment for separating the dry matter from the liquid.

In this context, one can treat said dry matter to separate on the one hand acids and organic salts and on the other hand the essential amino acids.

Best ways to achieve the invention

[0016] Green rye is a plant that is sown after the harvest of certain crops such as barley, wheat or other cereals in order to cover the topsoil and to prevent soil erosion and transmission. substances, including nitrates and pesticides, in groundwater. It has a rapid growth under conditions of unfavorable growth during the months of February to April and ensures a high rate of ground cover.

In the context of the present invention, the green rye is cut before the start of flowering. At this stage, the mass of green rye is already well developed, and its transformation consequently has a high yield. On the other hand, the plant is still little lignified, and therefore consumes little basis for releasing cellulose. The land is then used for seeding the main crop of the season, which is often corn.

The present invention proposes to recover the green rye at the time of cutting and put in silage for a longer or shorter period. Silage allows both the preservation of the raw material and its softening by preparing it for separation of the dry matter to provide plant fibers used for the manufacture of paper and juice for the manufacture of products derivatives for use in animal nutrition or the manufacture of food compounds.

At the silage silo outlet, the wet mass of green rye is put in a screw press to separate the compact mass called juice cake consisting of a large amount of organic acids. The two parts, namely the cake and the juice are subjected to different treatments. To extract the cellulose fibers by treatment of the cake, mechanical grinding and mixing operations are carried out.

To enhance the said juice, it is preferably carried out a treatment for separating the dry matter from the liquid to preserve the organic acids and reduce the volume of base necessary for the caustification of the cake.

The treatment of the cake comprises a phase of neutralization of residual acids and caustification after passing through the screw press. For this purpose, sodium hydroxide (NaOH), sodium sulphite (Na 2 S), sodium bicarbonate (Na 2 CO 3), sodium sulphate (Na 2 SO 4), calcium (CaO), potassium hydroxide (KOH), calcium carbonate Ca (OH) 2, or a mixture of these compounds or similar agents in aqueous solution. This caustification phase is carried out by soaking the cake in the basic solution. The basic pH of said aqueous solution is advantageously between 7 and 12 and preferably greater than 11.

The causticization phase of the cake is followed by a rinsing phase with water preferably combined with a fiber separation phase which is continuously carried out by sieving in a separator. Several passages of the solution through the separator may take place to collect the fibers for use in papermaking.

This way of operating to recover the fibers optimally ensures the singularization of cellulose fibers as well as the sterilization and elimination of persistent odors in the basic material, and the conservation of elasticity and elasticity. toughness for excellent bonding potential of said fibers. To limit the volume of basic solution used in the caustification process, it is extracted from the soaked cake by pressing the suspension and then supplemented by the addition of a base, in order to maintain the desired pH level, then reused.

To remove dissolved substances by the caustic treatment, it is necessary to separate a certain volume of solution in circulation. This volume of liquid effluents can be spread on agricultural land and can be used to recover its mineral content, particularly potassium (K) and calcium (Ca), which are key elements. for plant growth. The use of potassium hydroxide or potassium hydroxide (KOH), calcium oxide (CaO) or calcium hydroxide Ca (OH) 2, or the like for the preparation of the caustic solution is preferred over the use of sodium hydroxide, or soda (NaOH), because they can be used for plant nutrition. Despite the fact that a caustification of agricultural land is a necessary and standard treatment in agriculture, a neutralization of the caustic solution used may be necessary. Preferably, this neutralization is carried out with a portion of juice extracted from the initial material used in the process of the invention during the first phase of the process, this initial material comprising large quantities of organic acids.

The course of the operating phases is advantageously as follows: An assay of the material to be treated, in this case green rye or similar previously ensiled which is fed to a hammer mill and then to a screw press which separates the juice of the solid matter. The solid material is treated as mentioned above in a tank with a basic solution and the mixture is stored in a suspension tank. By pumping, the solution is transferred to a sieving unit for a first separation of the liquid and fibers which are rinsed and completely separated from the residual liquid by means of a screw press.

Given the fact that the initial material contains a large portion of organic acid rich juice and their salts, its preferred use is the acidification of animal feed. Especially in the breeding of pigs, organic acids are often used and appreciated for their effect of hygienization and improvement of the digestibility of food, which results in a significant increase in the daily weight gain of animals.

To maximize the recovery rate of the soluble components of the original material, to facilitate a maximum conversion of sugar into organic acids and to achieve a high level of acids relative to salts, the silage is carried out with a percentage of relatively high water, at least 65% and preferably above 70%. In order to obtain an optimal quality of the juice, in particular its lactic acid and acetic acid content, and more particularly the proportion of L-lactic acid relative to D-lactic acid. It is also possible to use specific bacteria for starting the silage. As soon as the desired juice quality is reached, this juice can be used directly as a starter crop.

The juice can also be treated separately for the production of different products for animal feed, the cosmetics industry or dietary products.

By way of examples, two tests were carried out with a mass of green rye resulting from a preliminary silage phase of several months.

Example 1: (a) A mass of 234 kg of green rye, which had been ensiled the previous year, with a solids content of 25.3%, was put in a screw press. (b) This operation yielded 1271 brown juice and 91 kg cake. Analysis of the juice recorded a residual amount of dry matter of 94 g / l, with a total amount of organic acids of 38 g / l and amino acids of 42 g / l. The dry matter content of the cake is 38.5%. (c) For the treatment of the cake, 33 I of a 2% solution of sodium hydroxide (NaOH) was prepared in a tank. The solution was prepared with 33 l of hot water at 60 ° C and 660 g NaOH. A mass of 20 kg of the cake was macerated in this solution for 15 minutes. (d) The next step was to dilute the solution containing the cake with hot water in a tank equipped with a mixer, and connected to a mechanical sieving and fiber separation unit. The suspension was treated in continuous circulation for 8 minutes, so that it made at least two passes through the sieving-separating mechanical aggregate. The fiber separation was done and they went into a paper production process. The SR (Schoppe-Riegler) value of the obtained paper was 49 and the measured tensile strength of the paper was 65 Nm / g.

Example 2: (e) Ensiled green rye was passed through the screw press as before (see (a)). (f) For the treatment of the cake, 33 l of a solution of 3% calcium oxide (CaO) was prepared in a tank, with 33 l of hot water at a temperature of 60 ° C and 1000 g ( CaO). A mass of 20 kg of the cake was soaked in this solution for 15 minutes. (g) The solution containing the cake was diluted with hot water, and subjected to stirring and then sieving and separating the fibers by a mechanical aggregate. Additional treatment of these wet fibers with CaO gave "hardly flammable" fibers according to the official flammability standard. (h) An additive has been added to the fibers, with the objective of improving the hygrophilicity and wettability of the fibers. Soaking the fibers in an additive solution gave very good results.

The present invention is not limited to the embodiments described, but may undergo various modifications and obvious variations for the skilled person. For example, it is obvious that the addition of the base will be limited to the volume required for the replacement of the base consumed during the treatment and therefore significantly less than the mass used in the examples mentioned.

Claims (11)

1. Process for the industrial processing of green rye for extracting cellulose fibers that can be used especially in the preparation of paper pulp, the manufacture of nonwoven products, the production of plant supports for aboveground crops, the production of material panels thermally insulating or the like, characterized in that, during a preparatory phase, a preliminary treatment of green rye is carried out by silage in a humid environment and in a confined atmosphere, in that, during an intermediate phase, from a mass of ensiled material, the separation of the solid material called "cake", and a suspension called "juice" and that it proceeds separately, during a phase final, the extraction of cellulose fibers by treatment of the cake. 2. Method according to claim 1, characterized in that, for effecting the separation of said cake and saidJus, during said intermediate phase from said mass of ensiled material, using a screw press. 3. Method according to claim 1, characterized in that, in order to extract the cellulose fibers by treatment of the cake during said final phase, a suspension is produced by adding to said cake an aqueous solution of a base and a reaction is carried out. stirring said suspension to neutralize the acids and give it a basic pH. 4. Method according to claim 3, characterized in that said aqueous solution of a base is dosed in such a way that the basic pH of said suspension is between 7 and 12 and preferably greater than 11. 5. Method according to claim 3, characterized in that said base is chosen from the following compounds: sodium hydroxide (NaOH), calcium oxide (CaO), potassium hydroxide (KOH), calcium carbonate Ca (OH) 2 hydroxide of sodium (NaOH), sodium sulfite (Na2S), sodium bicarbonate (Na2CO3), sodium sulfate (Na2SO4), calcium oxide (CaO), potassium hydroxide (KOH), calcium carbonate Ca (OH) 2 or mixtures of these compounds. 6. Process according to claim 3, characterized in that the aqueous solution of sodium hydroxide (NaOH) contains between 0.5 and 5% of (NaOH) and preferably between 1.0% and 2.5% of (NaOH). 7. Method according to claim 3, characterized in that the aqueous solution of calcium oxide (CaO) contains between 0.5 and 5% of (CaO) and preferably between 1.5% and 4% of (CaO) . 8. Process according to claim 1, characterized in that, to extract the cellulose fibers by treatment of the cake during said final phase, said cake is rinsed with hot water. 9. Method according to claim 8, characterized in that the hot water has a temperature substantially between 60 to 90 ° C. 10. Process according to claim 1, characterized in that a treatment of said juice is carried out in order to separate the dry matter from the liquid. 11. The method of claim 10, characterized in that said dry matter is treated to separate on the one hand the acids and organic salts and on the other hand the essential amino acids.