OA19091A

OA19091A - Method and unit for harvesting and processing water hyacinths.

Info

Publication number: OA19091A
Application number: OA1201800543
Authority: OA
Inventors: Rebeka Bahadorani; Pierre Bono
Original assignee: In-Between Sa
Priority date: 2016-07-07
Filing date: 2017-06-08
Publication date: 2020-01-20

Abstract

Method for harvesting and processing water hyacinths, characterized in that the following steps are performed: a) the water hyacinths growing in an aquatic medium are cut; b) the water hyacinths are collected on board a quayside barge (1); c) the collected water hyacinths are transferred onto draining racks (2) near the quayside; d) the drained hyacinths are washed with clean water; e) the washed water hyacinths are drained on vibrating belts (7) in order to remove some of the excess water; f) the water hyacinths are dried on a dryer (8) at a température of between 50 and 100°C for 5 to 17h; g) the water hyacinths and their seeds are steamsterilised at a température of between 80 and 100°C in order to stérilisé them; h) the sterilised water hyacinths and seeds are ground in order to make profitable use thereof.

Description

PROCESS AND UNIT FOR HARVESTING AND PROCESSÏNG WATER HYACINTHS

The présent invention falls within the field of the methods for haivesting and processïng water hyacinths.

The water hyacinth or Eichhornia crassipes is a freshwater aquatic plant, of the aquatic macrophyte type. This plant species is very invasive. It raises a problem -------bseause'^yf—its—rapîd—gr^vitr^nd—ferfog—ite—êeeomposition. Indccd, its rapid and widespread growth has an impact on the freshwater ecosystem. The spread of the water 10 hyacinth in its environment can namely smother the native species by forming, at the level of the lower strata, monospecific dense carpets, depriving them of vital light.

In addition., during its décomposition, the water hyacinth releases, in its aquatic medium, nutrients that can lead to eutrophication or anoxia of the environment, which represents a danger for aquatic biodiversity that can lead to the death of raany species 15 cohabiting with the water hyacinths.

In ..addition, the. water hyacinth seeds are long-J asti ng, the time of dormancy of the seeds is twenty years. These seeds tolerate dryness and germinale as soon as they are immersed in the aquatic medium. Thus, even m case of harvest, during storage, there is a risk of contamination, i.e., seed germination, in particular when the storage 20 environment is wet. Thus, it is necessary to be able to avoid fois risk of germination of water hyacinth seeds during storage in order to allow their profitable use in the industrial environment.

Therefore, in order to avoid the aforementioned phenomena, it is necessary to fmd an easy and quick solution for harvesting. processïng and profitably using the 25 water hyacinth in the industry.

The présent invention aims to cope with the drawbacks of the state of the art, by providing. a. method for. harvesting and .processïng water ..hyacinths, in which the following steps are performed :

a) the water hyacinths growing in an aquatic medium are eut ;

b) the water hyacinths are collected aboard a barge at berth ;

c) the collected water hyacinths are transferred onto draining means, such as draining racks, near the quayside ;

d) the drained hyacinths are washed with clean water ;

e) the washed hyacinths are drained on vibrating belts in order to partially elîminate the excess water ;

f) the water hyacinths are dried on a dryer at a température between 50 and 100°C for a period between 5h and 17h ;

g) steam sterilization at 80 to l00°C is performed, in order to sterilize the water hyacinths and their seeds ;

h} profitable for use.

In addition, according to further features of the method of the invention :

- the residual water resulting from the draining of step c) is recovered, said residual water is processed by UV sterilization in a purification plant in order to be discharged into the original aquatic medium of the water hyacinths ;

- the clean water of step d) consists of water withdrawn from the original aquatic medium of the water hyacinths, said withdrawn water being pumped by means of a pumping plant and filtered through a filtering grid comprising an opening diameter between 6 and 10 mm so as to make it clean for the washing step ;

- step d) is performed by washing at least twice with clean water the drained hyacinths in washing means, such as a washing container ;

- after the sterilization step g) and prior to the grinding step h), the sterilized water hyacinths are dried by a forced hot-air system ;

- after the grinding step (h), a micronization of the obtained ground materials is performed in order to allow their profitable use in the field of plastics processing or insulation materials ;

- the drying step f) is performed using a vertical hot-air dryer ;

- after the drying step f) and prior to the sterilization step g), the dried water hyacinths are concentrated in concentration means, such as a concentrator ;

- after step d) of washing said drained water hyacinths, the latter are eut into at least three or four lengths.

The présent invention also relates to a unit for harvesting and processing water hyacinths permitting to perform the method of the invention and in this order :

- a floating barge near the quayside, said barge being equipped with means for cutting the water hyacinthe, means for collecting and storing the eut water hyacinths, and means for transferring said water hyacinths to the quayside, said transfer means being aimed at transferring said water hyacinths onto draining means for draining the collected water hyacinths ;

- means for moving the drained water hyacinths to washing means connected to additional draining means ;

:drying means at the exit of said additional draining means :

- means for concentrating the dried water hyacinths at the exit of said 10 drying means ;

- means for sterilizing the concentrated water hyacinths at the exit of said concentration means ;

- means for grinding the sterilized water hyacinths at the exit of said sterilization means.

Further features and advantages of the invention will become clear from the following detailed description of non-restrictive embodiments of the invention, when referring to the attached figures, in which :

- figure 1 schematically shows a view of the unit for harvesting and processing water hyacinths ;

- figure 2 schematically shows a view of the vertical hot-air dryer of the unit for harvesting and processing water hyacinths.

The présent invention relates to a method for harvesting and processing water hyacinths.

The harvesting of water hyacinths occurs by means of a floating barge 1 25 equipped with means for cutting, means for collecting and storing 110 eut water hyacinths.

Thus, the implémentation of the method of the invention occurs by successively performing the following steps :

a) the water hyacinths growing in an aquatic medium are eut ;

b) the water hyacinths are collected aboard a barge 1 at berth.

Once they hâve been harvested, the method of the invention permits to transfer the collected water hyacinths onto draining means 2, namely draining racks 2, near the quaysïde.

The transfer of the harvested water hyacinths is performed using transfer means

3. According to a particular embodiment, when the ground allows the installation of rails, the transfer means 3 may consist in particular of rotating telescopic carnages capable of transferring the hyacinths from the boat to the draining racks 2 on the quayside.

Advantageously, the draining racks 2 are positioned near the quayside bordering the aquatic medium.

According to a particular embodiment, the draining racks 2 consist of stainless métal grids which are raised relative to the ground.

The stainless nature is essential to prevent prématuré wear of the draining racks 2 by the excess water and to avoid corrosion and dégradation due to rust.

Draining the harvested water hyacinths permits a first coarse removal of excess water in order to facilitate the processing of the hyacinths.

According to a particular embodiment of the invention, the excess water, i.e., the residual water from the draining, is recovered. Then, said residual water is processed by UV sterilization in a purification plant 4, for its discharge afterwards into the original aquatic medium of the water hyacinths.

After this first coarse draining on the draining racks 2, the drained water hyacinths are washed with clean water. According to a particular embodiment, the clean washing water consists of water withdrawn from the original aquatic medium of the water hyacinths. Said withdrawn water is pumped by means of a pumping plant 5 and filtered on fine gratings with a séparation diameter between 6 and 10 mm. Then, said water is sieved on fine gratings with perforations between 4 and 6 mm in order to make it clean for the washing step.

Advantageously, the washing is performed using washing means 6, in particular in a washing container 6, with clean water.

Advantageously, the washing operation is repeated several times.

Advantageously, the same quantity of material is washed at least twice. Nevertheless, depending on the pollution and the composition of the aquatic medium where the hyacinths were withdrawn, i.e., depending on the dirt of said aquatic iiving medium of the water hyacinths, additional washing cycles will be necessary. These washing cycles can reach up to ten successive washing cycles.

The washing step permits to remove the impurities bound to and still présent in the slack of drained water hyacinths and to purify them coarsely,

After washing, the washed water hyacinths are dried on a vibrating belt 7 in order to partially remove the excess wash water and to obtain the least hydrated possible material.

According to a particular embodiment of the invention, the vibrating belts 7 are 10 in the form of vibrating draining racks inclined at about 5° and the filtering grid of which has openings with a decreasing diameter ranging from 2 to 0.2 mm.

Advantageously, the material, i.e., the washed water hyacinth, is drained on a sériés of vibrating conveyor belts 7 of stainless métal mesh, as shown in figure 1.

According to a particular embodiment, the water residues, after passing on the 15 vibrating conveyor belts 7, are recovered for being UV sterilized and released into the aquatic medium.

According to the invention, the water hyacinths are dried using drying means 8, in particular on a dryer 8. Drying occurs at a température between 50 and 110°C for a period between 5h and 16h.

²⁰ According to a spécifie embodiment, said drying of the water hyacinths is performed at a température between 50 and 70°C for a period between 14h and 16h.

According to another preferred embodiment, said drying of the water hyacinths is performed at a température between 90 and 110°C for a period between 5h and 7h.

In ail cases, the drying must be performed at a température lower than 110°C, in 25 order to avoid damaging the fibers of the hyacinths.

According to a particular embodiment, said dryer 8 consists of a solar-powered vertical hot-air dryer 8, in particular for saving energy necessary for its operation, or powered by any other power supply system.

According to this particular embodiment and as illustrated in figure 2, this 30 vertical hot-air dryer 8 includes :

- in the upper portion an inlet 81, such as a conduit, permittîng the incorporation of the wet washed material to be dried ;

- over its full height, a sériés of meshed stainless steel conveyor belts 82 that vibrate and permit the graduai transport, from top to bottom, of the material to be dried, the grids permitting the passage of air ;

- in the lower portion, an outlet 83, such as a conduit, permitting the 5 évacuation of the dried material, i.e., the dried water hyacinths, to the outside of the vertical hot-air dryer 8.

It should be noted that the conveyor belts 82 are vibrating and thus avoid a static drying of the material. Indeed, a static drying is slower and less efficient than a dynamic drying by vibration.

In said vertical hot-air dryer 8, the presence in the lower portion of an air-inlet system 84a and in the upper portion of an air-outlet opening 84b will permit to gradually dry the material. The air circulation inside the dryer will thus facilitate the drying. In this dryer 8, the hot-air circulation, which is possible over the entire height, namely through the grids, will permit a graduai drying of the material. The hot air circulating through the dryer 8 has a température between 50 and 110°C.

At the exit 83 of the dryer 8, the dried material is recovered and the dried water hyacinths are concentrated using concentration means 9, in particular in a concentrator

9. The use of the concentrator 9 permits to improve the line of action and flow ofthe matter.

After passing through the dryer 8, the concentrated material is sterilized with steam at a température between 80 and 100°C, in order to sterilize the dried water hyacinths and their seeds. The sterilization is performed using steam sterilization means

10, in particular in a steam sterilizer 10.

This sterilization method and the température range used permit to avoid a 25 germination of the water hyacinth seeds and their prolifération. The sterilization permits to prevent said possible germination, namely when the grinding step is performed.

According to the method of the invention, in order to finalize the processing of the dried water hyacinths, the sterilized water hyacinths and their seeds are ground, in 30 order to be able to be profitably used later and at industrial level.

The grinding step is performed using grinding means 11, namely such as a grinder 11, permitting to obtain ground material having a grain size between 1 and 3 cm. This size of the ground material is necessary for ease of use in the industry, namely in the field of plastics processing and the insulation materials.

According to a particular embodiment, in order to optimize the grinding and to obtain the driest possible material, with a dry matter hydration rate of less than 20% 5 RH or Relative Humidity, it is possible to perform, after the sterilization step g) and prior to the grinding step h), a drying by ventilation of the sterilized material, i.e., the sterilized water hyacinth, by a forced hot-air system. This drying by ventilation is .performed in a forced air dryer 12.

The forced hot-air system permits to further dehydrate the sterilized hyacinth, namely by bringing it into contact with hot air at a température between 50 and 70°C.

According to another spécifie embodiment of the invention, after the grinding step h) is performed a micronization of the obtained ground materials, in order to permit their profitable use in the field of plastics processing and the insulation materials.

¹⁵ The micronization is performed in a micronizer 13 permitting to obtain a grain size ofthe ground materials of less than 1 mm.

This type of ground materials with very small grain size is easy to be profitable used.

According to another embodiment of the invention, the ground water hyacinth materials can be sieved using a sieve 14 for their grain shape to be easy to be used. The refusai of the sieve 14 can be used as fuel for supplying a steam boiler, thus permitting the operation of the steam sterilizer 10.

The present invention also relates to a unit for harvesting and processing the water hyacinths illustrated in figure 1, comprising in this order :

²⁵ - ^a floating barge (1) near the quayside, said barge (1) being equipped with means for cutting the water hyacinths, means for collecting and storing (110) the eut water hyacinths, and means for transferring (3) said water hyacinths to the quayside, said transfer means (3) being aimed at transferring said water hyacinths onto the draining means (2) aimed at draining the collected water hyacinths ;

³⁰ - means for moving the drained water hyacinths to washing means (6) connected to additional draining means ;

- drying means (8) at the exit of said additional draining means ;

i j

i

- means (9) for concentrating the dried water hyacinths at the exit of said drying means (8) ;

- means for sterilizing (10) the concentrated water hyacinths at the exit of said concentrating means (9) ;

- means for grinding (11) the sterilized water hyacinths at the exit of said sterilization means (10).

According to a particular embodiment, the unit for harvesting and processing the. water hyacinths may in addition include, at the exit ofthe steam sterilizer 10 a dryer 12 for further eliminating the remaining water.

¹⁰ - According to another particular embodiment of the invention, at the exit of the grinder 11, the ground materials of the dehydrated water hyacinths are micronized in a micronizer 13, then, optionally, the micronized ground materials are sieved using a sieve 14. Thus, this spécifie processing permits to facilitate their profitable industrial use, the obtained micronized and/or sieved hyacinth powder being stable, inert, without risk of germination and easily transportable.

Thus, the unit for harvesting and processing the water hyacinths pennits both to harvest and process the water hyacinths by transforming them into ground materials profitably used in the industry. Said obtained ground materials hâve such a low hydration rate, almost zéro, that the risk of germination during storage has been 20 eliminated. Thus, the ground materials are durable and inert, they can be used in the industry, for example in the field of plastics processing or the manufacture of insulation panels.

The method for harvesting and processing the water hyacinths and its harvesting unit represent a solution easy to be implemented for eliminating the pollution of the 25 aquatic médiums and for eliminating the water hyacinths. The method and the harvesting unit of the invention also permit a rapid and efficient processing of the harvested water hyacinths in order to be able to be profitably used at industrial level.

Claims

1, wherein after the drying step f) and prior to the sterilization step g), the dried water hyacinths are concentrated in concentrating means (9), such as a concentrator.

9. The method for harvesting and processing water hyacinths according to claim 1, wherein after the step d) of washing said drained water hyacinths, the latter are eut into at least three or four lengths.

²⁵ 10. A unit for harvesting and processing water hyacinth, wherein it comprises :

- a floating barge (1) near the quayside, said barge (1) being equipped with means for cutting the water hyacinths, means for collecting and storing (110) the eut water hyacinths, and means for transferring (3) said water hyacinths to the quayside ;

³⁰ - draining means (2) aimed at draining the collected water hyacinths, said transfer means (3) being aimed ai transferring said water hyacinths to said draining means (2) ;

- washing means (6) ;

- means for moving the drained water hyacinths to said washing means (6) ;

- additional draining means ;

- drying means (8) at the exit of said additional draining means ;

1. A method for harvesting and processing water hyacinths, wherein the following steps are performed:

5 a) the water hyacinths growing in an aquatic medium are eut ;

b) the water hyacinths are collected aboard a barge (1) at berth ;

c) the collected water hyacinths are transferred onto draining means (2), such as draining racks (2), near the quayside ;

d) the drained hyacinths are washed with clean water ;

10 e) the washed hyacinths are drained on vibrating belts (7) in order to partially eliminate the excess water ;

f) the water hyacinths are dried on a dryer (8) at a température between 50 and 100°C for a period between 5h and 17h ;

g) steam sterilization at 80 to 100°C is performed, in order to sterilize the

15 water hyacinths and their seeds ;

h) the sterilized water hyacinths and their seeds are ground in order to make them profitable for use.

2. The method for harvesting and processing water hyacinths according to

20 the preceding claim, wherein the residual water from the draining of step c) is recovered, said residual water is processed by UV sterilization within a purification plant (4) in order to discharge it into the original aquatic medium of the water hyacinths,

25

3. The method for harvesting and processing water hyacinths according to claim 1, wherein the clean water of step d) consists of water withdrawn from the original aquatic medium of the water hyacinths, said withdrawn water being pumped by means of a pumping plant (5) and filtered through a filtering grid comprising an opening diameter between 6 and 10 mm so as to make it clean for the washing step.

4. The method for harvesting and processing water hyacinths according to claim 1, wherein step d) is performed by washing the drained hyacinths at least twice with clean water in washing means (6), such as a washing container (6).

5 5. The method for harvesting and processing water hyacinths according to claim 1, wherein after the sterilization step g) and prior to the grinding step h), the sterilized water hyacinths are dried by a forced hot-air system.

6. The method for harvesting and processing water hyacinths according to

10 claim 1, wherein after the grinding step h) is performed a micronization of the obtained ground material in order to permit their profitable use in the field of plastics processing or insulation materials.

7. The method for harvesting and processing water hyacinths according to 15 claim 1, wherein the drying step f) is performed using a vertical hot-air dryer (8).

8. The method for harvesting and processing hyacinths according to claim

5 - means (9) for concentrating the dried water hyacinths at the exit of said drying means (8) ;

- means for sterilizing (10) the concentrated water hyacinth at the exit of said concentrating means (9) ;

- means for grinding (11) the sterilized water hyacinths at the exit of said 10 sterilization means (10).